From 2db84a8ee7cd3873e11eb0c13abc09869caa0042 Mon Sep 17 00:00:00 2001 From: Antonio Vazquez Date: Thu, 22 Sep 2022 11:52:48 +0200 Subject: Fix all merge conflicts There was a lot of conflicts and to solve, I refresh manually the source folders. --- source/blender/CMakeLists.txt | 4 +- source/blender/blendthumb/CMakeLists.txt | 2 +- .../blender/blendthumb/src/blendthumb_extract.cc | 8 +- source/blender/blenfont/BLF_api.h | 8 +- source/blender/blenfont/CMakeLists.txt | 1 - source/blender/blenfont/intern/blf.c | 28 +- source/blender/blenfont/intern/blf_font.c | 516 +- source/blender/blenfont/intern/blf_font_default.c | 71 +- source/blender/blenfont/intern/blf_glyph.c | 222 +- source/blender/blenfont/intern/blf_internal.h | 29 +- .../blender/blenfont/intern/blf_internal_types.h | 157 +- source/blender/blenfont/intern/blf_thumbs.c | 29 +- source/blender/blenkernel/BKE_DerivedMesh.h | 13 - source/blender/blenkernel/BKE_appdir.h | 31 +- source/blender/blenkernel/BKE_attribute.hh | 169 +- source/blender/blenkernel/BKE_attribute_math.hh | 225 +- source/blender/blenkernel/BKE_blender_version.h | 4 +- source/blender/blenkernel/BKE_bpath.h | 3 + source/blender/blenkernel/BKE_cachefile.h | 10 +- source/blender/blenkernel/BKE_cdderivedmesh.h | 4 - source/blender/blenkernel/BKE_cloth.h | 2 +- source/blender/blenkernel/BKE_collection.h | 13 +- source/blender/blenkernel/BKE_collision.h | 1 + source/blender/blenkernel/BKE_compute_contexts.hh | 46 + source/blender/blenkernel/BKE_crazyspace.hh | 53 + source/blender/blenkernel/BKE_cryptomatte.h | 2 + source/blender/blenkernel/BKE_cryptomatte.hh | 26 +- source/blender/blenkernel/BKE_curves.h | 2 +- source/blender/blenkernel/BKE_curves.hh | 131 +- source/blender/blenkernel/BKE_curves_utils.hh | 355 +- source/blender/blenkernel/BKE_customdata.h | 60 +- source/blender/blenkernel/BKE_deform.h | 80 +- source/blender/blenkernel/BKE_displist.h | 6 - source/blender/blenkernel/BKE_effect.h | 1 + source/blender/blenkernel/BKE_fcurve.h | 26 +- source/blender/blenkernel/BKE_fcurve_driver.h | 1 - source/blender/blenkernel/BKE_geometry_fields.hh | 176 +- source/blender/blenkernel/BKE_geometry_set.h | 3 +- source/blender/blenkernel/BKE_geometry_set.hh | 102 +- source/blender/blenkernel/BKE_global.h | 2 +- source/blender/blenkernel/BKE_gpencil_geom.h | 22 +- source/blender/blenkernel/BKE_icons.h | 4 +- source/blender/blenkernel/BKE_idprop.h | 8 +- source/blender/blenkernel/BKE_idprop.hh | 9 +- source/blender/blenkernel/BKE_idtype.h | 8 +- source/blender/blenkernel/BKE_image.h | 38 +- source/blender/blenkernel/BKE_image_format.h | 2 +- source/blender/blenkernel/BKE_image_save.h | 4 +- source/blender/blenkernel/BKE_key.h | 10 +- source/blender/blenkernel/BKE_lattice.h | 1 - source/blender/blenkernel/BKE_layer.h | 151 +- source/blender/blenkernel/BKE_lib_id.h | 83 +- source/blender/blenkernel/BKE_lib_override.h | 15 + .../blenkernel/BKE_lib_principle_properties.h | 85 - source/blender/blenkernel/BKE_lib_query.h | 1 - source/blender/blenkernel/BKE_lib_remap.h | 8 +- source/blender/blenkernel/BKE_main.h | 20 +- source/blender/blenkernel/BKE_main_namemap.h | 66 + source/blender/blenkernel/BKE_mball.h | 24 +- source/blender/blenkernel/BKE_mball_tessellate.h | 8 +- source/blender/blenkernel/BKE_mesh.h | 237 +- source/blender/blenkernel/BKE_mesh_fair.h | 14 +- .../blender/blenkernel/BKE_mesh_legacy_convert.h | 29 + source/blender/blenkernel/BKE_mesh_mapping.h | 64 +- source/blender/blenkernel/BKE_mesh_remap.h | 16 +- source/blender/blenkernel/BKE_mesh_remesh_voxel.h | 4 +- source/blender/blenkernel/BKE_mesh_sample.hh | 46 +- source/blender/blenkernel/BKE_modifier.h | 23 +- source/blender/blenkernel/BKE_nla.h | 2 +- source/blender/blenkernel/BKE_node.h | 77 +- source/blender/blenkernel/BKE_node_runtime.hh | 486 +- source/blender/blenkernel/BKE_node_tree_update.h | 1 + source/blender/blenkernel/BKE_object.h | 31 +- source/blender/blenkernel/BKE_outliner_treehash.h | 46 - source/blender/blenkernel/BKE_outliner_treehash.hh | 76 + source/blender/blenkernel/BKE_paint.h | 259 +- source/blender/blenkernel/BKE_particle.h | 2 +- source/blender/blenkernel/BKE_pbvh.h | 183 +- source/blender/blenkernel/BKE_pbvh_pixels.hh | 10 +- source/blender/blenkernel/BKE_pointcache.h | 2 +- source/blender/blenkernel/BKE_pointcloud.h | 8 +- source/blender/blenkernel/BKE_scene.h | 6 +- source/blender/blenkernel/BKE_screen.h | 12 +- source/blender/blenkernel/BKE_shrinkwrap.h | 4 +- source/blender/blenkernel/BKE_sound.h | 2 +- source/blender/blenkernel/BKE_spline.hh | 688 --- source/blender/blenkernel/BKE_subdiv_ccg.h | 1 + source/blender/blenkernel/BKE_subdiv_eval.h | 2 +- source/blender/blenkernel/BKE_subdiv_mesh.h | 8 +- source/blender/blenkernel/BKE_volume.h | 9 + source/blender/blenkernel/BKE_writeffmpeg.h | 2 +- source/blender/blenkernel/CMakeLists.txt | 44 +- source/blender/blenkernel/intern/DerivedMesh.cc | 223 +- source/blender/blenkernel/intern/action.c | 7 +- source/blender/blenkernel/intern/action_mirror.c | 2 +- source/blender/blenkernel/intern/anim_data.c | 13 +- source/blender/blenkernel/intern/anim_sys.c | 11 +- source/blender/blenkernel/intern/appdir.c | 54 +- source/blender/blenkernel/intern/armature.c | 12 +- source/blender/blenkernel/intern/armature_deform.c | 54 +- source/blender/blenkernel/intern/armature_update.c | 2 +- source/blender/blenkernel/intern/asset_catalog.cc | 2 +- source/blender/blenkernel/intern/attribute.cc | 241 +- .../blender/blenkernel/intern/attribute_access.cc | 451 +- .../blenkernel/intern/attribute_access_intern.hh | 55 +- source/blender/blenkernel/intern/attribute_math.cc | 69 +- .../blender/blenkernel/intern/blender_copybuffer.c | 2 +- source/blender/blenkernel/intern/blendfile.c | 6 +- .../blenkernel/intern/blendfile_link_append.c | 22 +- source/blender/blenkernel/intern/boids.c | 2 +- source/blender/blenkernel/intern/brush.cc | 24 +- source/blender/blenkernel/intern/bvhutils.cc | 64 +- source/blender/blenkernel/intern/cachefile.c | 8 +- source/blender/blenkernel/intern/camera.c | 95 +- source/blender/blenkernel/intern/cdderivedmesh.c | 40 - source/blender/blenkernel/intern/cloth.c | 23 +- source/blender/blenkernel/intern/collection.c | 98 +- source/blender/blenkernel/intern/collision.c | 3 +- source/blender/blenkernel/intern/colorband.c | 2 +- .../blender/blenkernel/intern/compute_contexts.cc | 38 + source/blender/blenkernel/intern/constraint.c | 118 +- source/blender/blenkernel/intern/context.c | 4 +- source/blender/blenkernel/intern/crazyspace.c | 584 --- source/blender/blenkernel/intern/crazyspace.cc | 655 +++ source/blender/blenkernel/intern/cryptomatte.cc | 79 +- .../blender/blenkernel/intern/cryptomatte_test.cc | 2 +- source/blender/blenkernel/intern/curve.cc | 8 +- .../blender/blenkernel/intern/curve_catmull_rom.cc | 26 +- source/blender/blenkernel/intern/curve_eval.cc | 587 --- .../blenkernel/intern/curve_legacy_convert.cc | 14 +- source/blender/blenkernel/intern/curve_nurbs.cc | 40 +- source/blender/blenkernel/intern/curve_poly.cc | 17 +- .../blenkernel/intern/curve_to_mesh_convert.cc | 10 +- source/blender/blenkernel/intern/curves.cc | 111 +- .../blender/blenkernel/intern/curves_geometry.cc | 340 +- source/blender/blenkernel/intern/curves_utils.cc | 27 + source/blender/blenkernel/intern/customdata.cc | 785 +-- source/blender/blenkernel/intern/data_transfer.c | 143 +- source/blender/blenkernel/intern/deform.c | 195 +- source/blender/blenkernel/intern/displist.cc | 164 +- source/blender/blenkernel/intern/dynamicpaint.c | 65 +- .../blender/blenkernel/intern/editmesh_tangent.c | 434 -- .../blender/blenkernel/intern/editmesh_tangent.cc | 331 ++ source/blender/blenkernel/intern/effect.c | 6 +- source/blender/blenkernel/intern/fcurve.c | 80 +- source/blender/blenkernel/intern/fcurve_driver.c | 1 + source/blender/blenkernel/intern/fcurve_test.cc | 1 - source/blender/blenkernel/intern/fluid.c | 192 +- source/blender/blenkernel/intern/fmodifier.c | 30 +- .../blenkernel/intern/geometry_component_curve.cc | 1463 ------ .../blenkernel/intern/geometry_component_curves.cc | 100 +- .../intern/geometry_component_edit_data.cc | 58 + .../intern/geometry_component_instances.cc | 3 +- .../blenkernel/intern/geometry_component_mesh.cc | 291 +- .../intern/geometry_component_pointcloud.cc | 24 +- .../blender/blenkernel/intern/geometry_fields.cc | 365 ++ source/blender/blenkernel/intern/geometry_set.cc | 115 +- .../blenkernel/intern/geometry_set_instances.cc | 4 +- source/blender/blenkernel/intern/gpencil.c | 6 +- source/blender/blenkernel/intern/gpencil_curve.c | 11 +- source/blender/blenkernel/intern/gpencil_geom.cc | 177 +- .../blender/blenkernel/intern/gpencil_modifier.c | 7 +- source/blender/blenkernel/intern/icons_rasterize.c | 2 +- source/blender/blenkernel/intern/idprop.c | 10 +- source/blender/blenkernel/intern/idprop_create.cc | 12 +- source/blender/blenkernel/intern/idtype.c | 39 +- source/blender/blenkernel/intern/image.cc | 378 +- source/blender/blenkernel/intern/image_gpu.cc | 20 +- .../blenkernel/intern/image_partial_update.cc | 2 +- source/blender/blenkernel/intern/image_save.cc | 35 +- source/blender/blenkernel/intern/image_test.cc | 19 +- source/blender/blenkernel/intern/ipo.c | 6 +- source/blender/blenkernel/intern/key.c | 185 +- source/blender/blenkernel/intern/lattice.c | 17 +- source/blender/blenkernel/intern/lattice_deform.c | 6 +- source/blender/blenkernel/intern/layer.c | 211 +- source/blender/blenkernel/intern/layer_utils.c | 127 +- source/blender/blenkernel/intern/lib_id.c | 368 +- source/blender/blenkernel/intern/lib_id_delete.c | 9 +- .../blender/blenkernel/intern/lib_id_remapper.cc | 1 + .../blenkernel/intern/lib_id_remapper_test.cc | 1 + source/blender/blenkernel/intern/lib_id_test.cc | 386 +- source/blender/blenkernel/intern/lib_override.cc | 583 ++- .../blenkernel/intern/lib_principle_properties.c | 106 - source/blender/blenkernel/intern/lib_query.c | 14 +- source/blender/blenkernel/intern/lib_remap.c | 7 +- source/blender/blenkernel/intern/library.c | 26 +- source/blender/blenkernel/intern/light.c | 3 +- source/blender/blenkernel/intern/lightprobe.c | 2 +- source/blender/blenkernel/intern/linestyle.c | 7 +- source/blender/blenkernel/intern/main.c | 5 + source/blender/blenkernel/intern/main_namemap.cc | 500 ++ source/blender/blenkernel/intern/mask.c | 4 +- source/blender/blenkernel/intern/material.c | 23 +- source/blender/blenkernel/intern/mball.c | 754 --- source/blender/blenkernel/intern/mball.cc | 715 +++ .../blender/blenkernel/intern/mball_tessellate.c | 87 +- source/blender/blenkernel/intern/mesh.cc | 482 +- .../blenkernel/intern/mesh_boolean_convert.cc | 114 +- .../blender/blenkernel/intern/mesh_calc_edges.cc | 14 +- source/blender/blenkernel/intern/mesh_convert.cc | 612 +-- source/blender/blenkernel/intern/mesh_debug.cc | 9 +- source/blender/blenkernel/intern/mesh_evaluate.cc | 226 +- source/blender/blenkernel/intern/mesh_fair.cc | 85 +- source/blender/blenkernel/intern/mesh_iterators.c | 33 +- .../blenkernel/intern/mesh_legacy_convert.cc | 306 +- source/blender/blenkernel/intern/mesh_mapping.c | 1158 ----- source/blender/blenkernel/intern/mesh_mapping.cc | 1167 +++++ source/blender/blenkernel/intern/mesh_merge.c | 96 +- .../blenkernel/intern/mesh_merge_customdata.cc | 15 +- source/blender/blenkernel/intern/mesh_mirror.c | 40 +- source/blender/blenkernel/intern/mesh_normals.cc | 160 +- source/blender/blenkernel/intern/mesh_remap.c | 95 +- .../blender/blenkernel/intern/mesh_remesh_voxel.cc | 104 +- source/blender/blenkernel/intern/mesh_runtime.cc | 54 +- source/blender/blenkernel/intern/mesh_sample.cc | 152 +- source/blender/blenkernel/intern/mesh_tangent.c | 741 --- source/blender/blenkernel/intern/mesh_tangent.cc | 605 +++ source/blender/blenkernel/intern/mesh_tessellate.c | 342 -- .../blender/blenkernel/intern/mesh_tessellate.cc | 343 ++ source/blender/blenkernel/intern/mesh_validate.cc | 188 +- source/blender/blenkernel/intern/mesh_wrapper.cc | 30 +- source/blender/blenkernel/intern/modifier.c | 53 +- source/blender/blenkernel/intern/movieclip.c | 2 +- source/blender/blenkernel/intern/multires.c | 25 +- .../blender/blenkernel/intern/multires_reshape.c | 3 +- .../blender/blenkernel/intern/multires_reshape.h | 8 + .../intern/multires_reshape_apply_base.c | 31 +- .../blenkernel/intern/multires_reshape_smooth.c | 21 +- .../blenkernel/intern/multires_reshape_subdivide.c | 23 +- .../blenkernel/intern/multires_reshape_util.c | 23 +- .../blenkernel/intern/multires_reshape_vertcos.c | 3 +- .../blenkernel/intern/multires_unsubdivide.c | 51 +- source/blender/blenkernel/intern/nla.c | 7 +- source/blender/blenkernel/intern/node.cc | 277 +- source/blender/blenkernel/intern/node_runtime.cc | 432 ++ .../blender/blenkernel/intern/node_tree_update.cc | 553 +-- source/blender/blenkernel/intern/object.cc | 191 +- source/blender/blenkernel/intern/object_deform.c | 16 +- source/blender/blenkernel/intern/object_dupli.cc | 46 +- source/blender/blenkernel/intern/object_update.c | 59 +- source/blender/blenkernel/intern/ocean.c | 7 +- .../blender/blenkernel/intern/outliner_treehash.c | 238 - .../blender/blenkernel/intern/outliner_treehash.cc | 209 + source/blender/blenkernel/intern/packedFile.c | 36 +- source/blender/blenkernel/intern/paint.c | 2348 --------- source/blender/blenkernel/intern/paint.cc | 2887 +++++++++++ source/blender/blenkernel/intern/particle.c | 69 +- source/blender/blenkernel/intern/particle_child.c | 9 +- .../blenkernel/intern/particle_distribute.c | 40 +- source/blender/blenkernel/intern/particle_system.c | 12 +- source/blender/blenkernel/intern/pbvh.c | 286 +- source/blender/blenkernel/intern/pbvh.cc | 26 +- source/blender/blenkernel/intern/pbvh_bmesh.c | 80 +- source/blender/blenkernel/intern/pbvh_intern.h | 16 +- source/blender/blenkernel/intern/pbvh_pixels.cc | 4 +- source/blender/blenkernel/intern/pointcache.c | 90 +- source/blender/blenkernel/intern/pointcloud.cc | 119 +- source/blender/blenkernel/intern/report.c | 16 +- source/blender/blenkernel/intern/rigidbody.c | 41 +- source/blender/blenkernel/intern/scene.cc | 86 +- source/blender/blenkernel/intern/screen.c | 44 +- source/blender/blenkernel/intern/shader_fx.c | 3 +- source/blender/blenkernel/intern/shrinkwrap.c | 27 +- source/blender/blenkernel/intern/simulation.cc | 6 +- source/blender/blenkernel/intern/softbody.c | 38 +- source/blender/blenkernel/intern/sound.c | 6 +- source/blender/blenkernel/intern/speaker.c | 2 +- source/blender/blenkernel/intern/spline_base.cc | 526 -- source/blender/blenkernel/intern/spline_bezier.cc | 646 --- source/blender/blenkernel/intern/spline_nurbs.cc | 395 -- source/blender/blenkernel/intern/spline_poly.cc | 97 - source/blender/blenkernel/intern/studiolight.c | 22 +- source/blender/blenkernel/intern/subdiv_ccg.c | 5 + source/blender/blenkernel/intern/subdiv_ccg_mask.c | 7 +- .../blenkernel/intern/subdiv_ccg_material.c | 14 +- .../blenkernel/intern/subdiv_converter_mesh.c | 42 +- .../intern/subdiv_displacement_multires.c | 7 +- source/blender/blenkernel/intern/subdiv_eval.c | 16 +- source/blender/blenkernel/intern/subdiv_foreach.c | 85 +- source/blender/blenkernel/intern/subdiv_mesh.c | 1201 ----- source/blender/blenkernel/intern/subdiv_mesh.cc | 1230 +++++ source/blender/blenkernel/intern/subdiv_modifier.c | 5 - source/blender/blenkernel/intern/subsurf_ccg.c | 21 +- source/blender/blenkernel/intern/text.c | 2 +- source/blender/blenkernel/intern/texture.c | 3 +- source/blender/blenkernel/intern/tracking_detect.c | 4 +- .../blender/blenkernel/intern/tracking_stabilize.c | 2 +- .../blender/blenkernel/intern/type_conversions.cc | 61 +- source/blender/blenkernel/intern/unit.c | 40 +- source/blender/blenkernel/intern/vfont.c | 23 +- source/blender/blenkernel/intern/volume.cc | 52 +- source/blender/blenkernel/intern/volume_to_mesh.cc | 6 +- source/blender/blenkernel/intern/workspace.c | 596 --- source/blender/blenkernel/intern/workspace.cc | 610 +++ source/blender/blenkernel/intern/world.c | 3 +- source/blender/blenkernel/intern/writeffmpeg.c | 2 +- source/blender/blenkernel/nla_private.h | 13 +- source/blender/blenlib/BLI_any.hh | 4 +- source/blender/blenlib/BLI_array_store.h | 1 - source/blender/blenlib/BLI_array_utils.hh | 110 + source/blender/blenlib/BLI_bit_vector.hh | 529 ++ source/blender/blenlib/BLI_bitmap.h | 13 +- source/blender/blenlib/BLI_compute_context.hh | 173 + source/blender/blenlib/BLI_cpp_type.hh | 2 +- source/blender/blenlib/BLI_fileops.h | 1 + source/blender/blenlib/BLI_float3x3.hh | 16 + source/blender/blenlib/BLI_float4x4.hh | 2 +- source/blender/blenlib/BLI_function_ref.hh | 1 - source/blender/blenlib/BLI_generic_span.hh | 57 + .../blender/blenlib/BLI_generic_virtual_array.hh | 1 + source/blender/blenlib/BLI_index_range.hh | 46 +- source/blender/blenlib/BLI_kdopbvh.h | 23 + source/blender/blenlib/BLI_lazy_threading.hh | 83 + source/blender/blenlib/BLI_length_parameterize.hh | 49 +- source/blender/blenlib/BLI_listbase.h | 23 +- source/blender/blenlib/BLI_listbase_wrapper.hh | 4 +- source/blender/blenlib/BLI_map.hh | 4 +- source/blender/blenlib/BLI_math_color.h | 4 +- source/blender/blenlib/BLI_math_geom.h | 4 +- source/blender/blenlib/BLI_math_matrix.h | 272 +- source/blender/blenlib/BLI_math_rotation.h | 101 +- source/blender/blenlib/BLI_math_rotation.hh | 9 + source/blender/blenlib/BLI_math_vector.h | 88 +- source/blender/blenlib/BLI_memory_utils.hh | 43 +- source/blender/blenlib/BLI_multi_value_map.hh | 13 + source/blender/blenlib/BLI_path_util.h | 32 +- source/blender/blenlib/BLI_pool.hh | 84 + source/blender/blenlib/BLI_probing_strategies.hh | 6 +- source/blender/blenlib/BLI_scanfill.h | 2 +- source/blender/blenlib/BLI_serialize.hh | 2 - source/blender/blenlib/BLI_set.hh | 4 +- source/blender/blenlib/BLI_string_utf8.h | 16 +- source/blender/blenlib/BLI_task.hh | 20 + source/blender/blenlib/BLI_utildefines.h | 2 +- source/blender/blenlib/BLI_vector_adaptor.hh | 88 - source/blender/blenlib/BLI_vector_set.hh | 2 +- source/blender/blenlib/BLI_virtual_array.hh | 88 +- source/blender/blenlib/CMakeLists.txt | 26 +- source/blender/blenlib/intern/BLI_index_range.cc | 30 + source/blender/blenlib/intern/BLI_kdopbvh.c | 2 +- source/blender/blenlib/intern/BLI_memarena.c | 3 +- source/blender/blenlib/intern/BLI_memblock.c | 1 - source/blender/blenlib/intern/array_utils.cc | 31 + source/blender/blenlib/intern/bitmap.c | 20 + source/blender/blenlib/intern/boxpack_2d.c | 1 - source/blender/blenlib/intern/compute_context.cc | 48 + source/blender/blenlib/intern/cpp_type.cc | 1 + source/blender/blenlib/intern/filereader_zstd.c | 5 +- .../blenlib/intern/generic_virtual_array.cc | 4 +- source/blender/blenlib/intern/index_mask.cc | 5 +- source/blender/blenlib/intern/lazy_threading.cc | 30 + source/blender/blenlib/intern/math_geom.c | 6 +- source/blender/blenlib/intern/math_matrix.c | 174 +- source/blender/blenlib/intern/math_rotation.c | 150 +- source/blender/blenlib/intern/math_rotation.cc | 13 + source/blender/blenlib/intern/mesh_boolean.cc | 34 +- source/blender/blenlib/intern/mesh_intersect.cc | 2 +- source/blender/blenlib/intern/noise.c | 8 +- source/blender/blenlib/intern/noise.cc | 69 +- source/blender/blenlib/intern/path_util.c | 105 +- source/blender/blenlib/intern/rct.c | 4 +- source/blender/blenlib/intern/scanfill.c | 2 +- source/blender/blenlib/intern/smallhash.c | 3 +- source/blender/blenlib/intern/storage.c | 2 +- source/blender/blenlib/intern/string_cursor_utf8.c | 2 +- source/blender/blenlib/intern/string_search.cc | 4 +- source/blender/blenlib/intern/string_utf8.c | 56 +- source/blender/blenlib/intern/system.c | 14 +- source/blender/blenlib/intern/task_pool.cc | 8 +- source/blender/blenlib/intern/task_range.cc | 3 + source/blender/blenlib/intern/winstuff.c | 33 +- .../blender/blenlib/tests/BLI_array_store_test.cc | 10 +- .../blender/blenlib/tests/BLI_bit_vector_test.cc | 186 + source/blender/blenlib/tests/BLI_bitmap_test.cc | 46 + source/blender/blenlib/tests/BLI_float3x3_test.cc | 16 + .../blender/blenlib/tests/BLI_index_range_test.cc | 63 + .../blenlib/tests/BLI_length_parameterize_test.cc | 20 +- .../blenlib/tests/BLI_math_rotation_test.cc | 103 + source/blender/blenlib/tests/BLI_path_util_test.cc | 7 + source/blender/blenlib/tests/BLI_pool_test.cc | 51 + source/blender/blenlib/tests/BLI_set_test.cc | 10 +- .../blenlib/tests/BLI_string_search_test.cc | 2 +- source/blender/blenlib/tests/BLI_vector_test.cc | 2 +- .../blenlib/tests/performance/CMakeLists.txt | 4 + source/blender/blenloader/BLO_blend_validate.h | 8 + source/blender/blenloader/BLO_read_write.h | 5 +- source/blender/blenloader/BLO_readfile.h | 8 +- source/blender/blenloader/BLO_undofile.h | 8 + source/blender/blenloader/CMakeLists.txt | 27 +- source/blender/blenloader/intern/blend_validate.c | 200 - source/blender/blenloader/intern/blend_validate.cc | 202 + source/blender/blenloader/intern/readblenentry.c | 453 -- source/blender/blenloader/intern/readblenentry.cc | 458 ++ source/blender/blenloader/intern/readfile.c | 5152 ------------------- source/blender/blenloader/intern/readfile.cc | 5211 ++++++++++++++++++++ source/blender/blenloader/intern/readfile.h | 10 + .../blender/blenloader/intern/readfile_tempload.c | 59 - .../blender/blenloader/intern/readfile_tempload.cc | 60 + source/blender/blenloader/intern/undofile.c | 344 -- source/blender/blenloader/intern/undofile.cc | 349 ++ source/blender/blenloader/intern/versioning_250.c | 19 +- source/blender/blenloader/intern/versioning_280.c | 15 +- source/blender/blenloader/intern/versioning_290.c | 26 +- source/blender/blenloader/intern/versioning_300.c | 3288 ------------ source/blender/blenloader/intern/versioning_300.cc | 3441 +++++++++++++ source/blender/blenloader/intern/versioning_400.cc | 52 + .../blender/blenloader/intern/versioning_common.cc | 2 + .../blender/blenloader/intern/versioning_cycles.c | 3 - .../blenloader/intern/versioning_defaults.c | 32 +- .../blender/blenloader/intern/versioning_legacy.c | 8 +- .../blender/blenloader/intern/versioning_userdef.c | 5 +- source/blender/blenloader/intern/writefile.c | 1608 ------ source/blender/blenloader/intern/writefile.cc | 1618 ++++++ .../tests/blendfile_loading_base_test.cc | 10 +- source/blender/blentranslation/BLT_translation.h | 2 +- .../blender/blentranslation/msgfmt/CMakeLists.txt | 21 +- source/blender/bmesh/CMakeLists.txt | 4 +- source/blender/bmesh/bmesh.h | 2 +- source/blender/bmesh/intern/bmesh_construct.c | 46 +- source/blender/bmesh/intern/bmesh_core.c | 2 +- source/blender/bmesh/intern/bmesh_delete.c | 7 +- source/blender/bmesh/intern/bmesh_interp.c | 4 +- source/blender/bmesh/intern/bmesh_log.c | 32 +- source/blender/bmesh/intern/bmesh_log.h | 115 +- source/blender/bmesh/intern/bmesh_marking.c | 4 +- source/blender/bmesh/intern/bmesh_mesh.c | 1354 ----- source/blender/bmesh/intern/bmesh_mesh.cc | 1367 +++++ source/blender/bmesh/intern/bmesh_mesh.h | 2 +- source/blender/bmesh/intern/bmesh_mesh_convert.cc | 346 +- source/blender/bmesh/intern/bmesh_mesh_convert.h | 2 +- .../blender/bmesh/intern/bmesh_mesh_tessellate.c | 2 +- source/blender/bmesh/intern/bmesh_query.h | 1 - source/blender/bmesh/intern/bmesh_query_uv.c | 187 - source/blender/bmesh/intern/bmesh_query_uv.cc | 191 + source/blender/bmesh/intern/bmesh_structure.c | 3 +- source/blender/bmesh/operators/bmo_connect.c | 2 +- .../bmesh/operators/bmo_connect_nonplanar.c | 4 +- source/blender/bmesh/operators/bmo_connect_pair.c | 24 +- source/blender/bmesh/operators/bmo_create.c | 1 - .../blender/bmesh/operators/bmo_join_triangles.c | 4 +- source/blender/bmesh/operators/bmo_poke.c | 15 +- source/blender/bmesh/operators/bmo_primitive.c | 32 +- source/blender/bmesh/operators/bmo_removedoubles.c | 4 +- source/blender/bmesh/operators/bmo_subdivide.c | 4 +- .../bmesh/operators/bmo_subdivide_edgering.c | 28 +- source/blender/bmesh/operators/bmo_utils.c | 4 +- source/blender/bmesh/tools/bmesh_bevel.c | 146 +- source/blender/bmesh/tools/bmesh_path_region_uv.c | 9 +- source/blender/bmesh/tools/bmesh_path_region_uv.h | 6 +- source/blender/bmesh/tools/bmesh_path_uv.c | 207 +- source/blender/bmesh/tools/bmesh_path_uv.h | 10 +- source/blender/compositor/CMakeLists.txt | 1328 ++--- source/blender/compositor/COM_compositor.h | 2 +- source/blender/compositor/intern/COM_Node.h | 4 +- .../blender/compositor/nodes/COM_AlphaOverNode.cc | 4 +- .../compositor/nodes/COM_AntiAliasingNode.cc | 4 +- source/blender/compositor/nodes/COM_BlurNode.cc | 4 +- .../blender/compositor/nodes/COM_BokehBlurNode.cc | 2 +- .../blender/compositor/nodes/COM_BokehImageNode.cc | 2 +- source/blender/compositor/nodes/COM_BoxMaskNode.cc | 2 +- .../blender/compositor/nodes/COM_BrightnessNode.cc | 2 +- .../compositor/nodes/COM_ChannelMatteNode.cc | 4 +- .../compositor/nodes/COM_ChromaMatteNode.cc | 2 +- .../compositor/nodes/COM_ColorBalanceNode.cc | 2 +- .../compositor/nodes/COM_ColorCorrectionNode.cc | 2 +- .../blender/compositor/nodes/COM_ColorCurveNode.cc | 4 +- .../blender/compositor/nodes/COM_ColorMatteNode.cc | 2 +- .../blender/compositor/nodes/COM_ColorRampNode.cc | 2 +- .../blender/compositor/nodes/COM_ColorSpillNode.cc | 2 +- .../compositor/nodes/COM_CombineColorNode.cc | 2 +- .../compositor/nodes/COM_CombineColorNodeLegacy.cc | 2 +- .../blender/compositor/nodes/COM_CompositorNode.cc | 2 +- .../compositor/nodes/COM_ConvertAlphaNode.cc | 2 +- .../compositor/nodes/COM_ConvertColorSpaceNode.cc | 4 +- source/blender/compositor/nodes/COM_CropNode.cc | 2 +- .../compositor/nodes/COM_CryptomatteNode.cc | 5 +- source/blender/compositor/nodes/COM_DefocusNode.cc | 4 +- source/blender/compositor/nodes/COM_DenoiseNode.cc | 4 +- .../blender/compositor/nodes/COM_DespeckleNode.cc | 2 +- .../compositor/nodes/COM_DifferenceMatteNode.cc | 2 +- .../compositor/nodes/COM_DilateErodeNode.cc | 9 +- .../compositor/nodes/COM_DirectionalBlurNode.cc | 2 +- .../compositor/nodes/COM_DistanceMatteNode.cc | 4 +- .../compositor/nodes/COM_DoubleEdgeMaskNode.cc | 2 +- source/blender/compositor/nodes/COM_FilterNode.cc | 16 +- source/blender/compositor/nodes/COM_GlareNode.cc | 4 +- .../nodes/COM_HueSaturationValueCorrectNode.cc | 2 +- source/blender/compositor/nodes/COM_IDMaskNode.cc | 2 +- source/blender/compositor/nodes/COM_ImageNode.cc | 2 +- source/blender/compositor/nodes/COM_InpaintNode.cc | 2 +- source/blender/compositor/nodes/COM_InvertNode.cc | 2 +- source/blender/compositor/nodes/COM_KeyingNode.cc | 4 +- .../compositor/nodes/COM_KeyingScreenNode.cc | 2 +- .../compositor/nodes/COM_LensDistortionNode.cc | 2 +- .../compositor/nodes/COM_LuminanceMatteNode.cc | 2 +- source/blender/compositor/nodes/COM_MapUVNode.cc | 2 +- .../blender/compositor/nodes/COM_MapValueNode.cc | 2 +- source/blender/compositor/nodes/COM_MaskNode.cc | 4 +- source/blender/compositor/nodes/COM_MixNode.cc | 2 +- .../blender/compositor/nodes/COM_MovieClipNode.cc | 2 +- .../compositor/nodes/COM_MovieDistortionNode.cc | 2 +- .../blender/compositor/nodes/COM_OutputFileNode.cc | 10 +- .../compositor/nodes/COM_PlaneTrackDeformNode.cc | 2 +- source/blender/compositor/nodes/COM_ScaleNode.cc | 15 +- .../compositor/nodes/COM_SeparateColorNode.cc | 4 +- .../nodes/COM_SeparateColorNodeLegacy.cc | 2 +- .../compositor/nodes/COM_SplitViewerNode.cc | 2 +- .../compositor/nodes/COM_Stabilize2dNode.cc | 2 +- .../blender/compositor/nodes/COM_SunBeamsNode.cc | 2 +- .../blender/compositor/nodes/COM_SwitchViewNode.cc | 2 +- source/blender/compositor/nodes/COM_TextureNode.cc | 2 +- source/blender/compositor/nodes/COM_TimeNode.cc | 2 +- source/blender/compositor/nodes/COM_TonemapNode.cc | 2 +- .../compositor/nodes/COM_TrackPositionNode.cc | 2 +- .../blender/compositor/nodes/COM_TranslateNode.cc | 4 +- .../blender/compositor/nodes/COM_VectorBlurNode.cc | 4 +- .../compositor/nodes/COM_VectorCurveNode.cc | 2 +- source/blender/compositor/nodes/COM_ViewerNode.cc | 2 +- .../operations/COM_BokehImageOperation.h | 4 +- .../compositor/operations/COM_BoxMaskOperation.h | 4 +- .../operations/COM_BrightnessOperation.cc | 4 +- .../operations/COM_CompositorOperation.cc | 9 +- .../operations/COM_CurveBaseOperation.cc | 2 +- .../compositor/operations/COM_CurveBaseOperation.h | 2 +- .../compositor/operations/COM_DenoiseOperation.cc | 4 +- .../compositor/operations/COM_DenoiseOperation.h | 6 +- .../operations/COM_DirectionalBlurOperation.h | 4 +- .../operations/COM_DistanceRGBMatteOperation.h | 4 +- .../operations/COM_DoubleEdgeMaskOperation.cc | 4 +- .../compositor/operations/COM_GlareBaseOperation.h | 8 +- .../operations/COM_GlareFogGlowOperation.cc | 2 +- .../operations/COM_GlareFogGlowOperation.h | 2 +- .../operations/COM_GlareGhostOperation.cc | 2 +- .../operations/COM_GlareGhostOperation.h | 2 +- .../operations/COM_GlareSimpleStarOperation.cc | 2 +- .../operations/COM_GlareSimpleStarOperation.h | 2 +- .../operations/COM_GlareStreaksOperation.cc | 2 +- .../operations/COM_GlareStreaksOperation.h | 2 +- .../operations/COM_GlareThresholdOperation.h | 4 +- .../compositor/operations/COM_MapValueOperation.cc | 4 +- .../compositor/operations/COM_MapValueOperation.h | 4 +- .../operations/COM_MovieClipOperation.cc | 2 +- .../operations/COM_OutputFileMultiViewOperation.cc | 4 +- .../operations/COM_OutputFileMultiViewOperation.h | 4 +- .../operations/COM_OutputFileOperation.cc | 2 +- .../operations/COM_OutputFileOperation.h | 2 +- .../compositor/operations/COM_RenderLayersProg.cc | 4 +- .../compositor/operations/COM_SMAAOperation.cc | 2 +- .../compositor/operations/COM_ScaleOperation.cc | 2 +- .../compositor/operations/COM_TextureOperation.cc | 5 +- .../compositor/operations/COM_TonemapOperation.cc | 4 +- .../compositor/operations/COM_TonemapOperation.h | 8 +- .../operations/COM_VectorBlurOperation.cc | 7 +- .../operations/COM_VectorBlurOperation.h | 4 +- .../compositor/operations/COM_ViewerOperation.cc | 6 +- .../compositor/realtime_compositor/CMakeLists.txt | 66 + .../realtime_compositor/COM_compile_state.hh | 170 + .../compositor/realtime_compositor/COM_context.hh | 72 + .../COM_conversion_operation.hh | 158 + .../compositor/realtime_compositor/COM_domain.hh | 166 + .../realtime_compositor/COM_evaluator.hh | 170 + .../realtime_compositor/COM_input_descriptor.hh | 34 + .../COM_input_single_value_operation.hh | 46 + .../realtime_compositor/COM_node_operation.hh | 56 + .../realtime_compositor/COM_operation.hh | 175 + .../COM_realize_on_domain_operation.hh | 49 + .../COM_reduce_to_single_value_operation.hh | 31 + .../compositor/realtime_compositor/COM_result.hh | 234 + .../realtime_compositor/COM_scheduler.hh | 21 + .../realtime_compositor/COM_shader_node.hh | 87 + .../realtime_compositor/COM_shader_operation.hh | 242 + .../realtime_compositor/COM_simple_operation.hh | 64 + .../COM_static_shader_manager.hh | 33 + .../realtime_compositor/COM_texture_pool.hh | 86 + .../realtime_compositor/COM_utilities.hh | 71 + .../realtime_compositor/intern/compile_state.cc | 168 + .../realtime_compositor/intern/context.cc | 36 + .../intern/conversion_operation.cc | 239 + .../realtime_compositor/intern/domain.cc | 38 + .../realtime_compositor/intern/evaluator.cc | 170 + .../intern/input_single_value_operation.cc | 59 + .../realtime_compositor/intern/node_operation.cc | 67 + .../realtime_compositor/intern/operation.cc | 206 + .../intern/realize_on_domain_operation.cc | 130 + .../intern/reduce_to_single_value_operation.cc | 67 + .../realtime_compositor/intern/result.cc | 257 + .../realtime_compositor/intern/scheduler.cc | 314 ++ .../realtime_compositor/intern/shader_node.cc | 157 + .../realtime_compositor/intern/shader_operation.cc | 526 ++ .../realtime_compositor/intern/simple_operation.cc | 55 + .../intern/static_shader_manager.cc | 24 + .../realtime_compositor/intern/texture_pool.cc | 88 + .../realtime_compositor/intern/utilities.cc | 134 + source/blender/datatoc/datatoc_icon.py | 4 +- source/blender/depsgraph/CMakeLists.txt | 5 +- source/blender/depsgraph/DEG_depsgraph.h | 6 +- source/blender/depsgraph/DEG_depsgraph_build.h | 6 +- .../depsgraph/intern/builder/deg_builder.cc | 129 +- .../blender/depsgraph/intern/builder/deg_builder.h | 18 +- .../depsgraph/intern/builder/deg_builder_cache.cc | 17 +- .../depsgraph/intern/builder/deg_builder_cache.h | 24 +- .../depsgraph/intern/builder/deg_builder_cycle.h | 6 +- .../depsgraph/intern/builder/deg_builder_key.cc | 96 + .../depsgraph/intern/builder/deg_builder_key.h | 201 + .../depsgraph/intern/builder/deg_builder_map.h | 6 +- .../depsgraph/intern/builder/deg_builder_nodes.cc | 176 +- .../depsgraph/intern/builder/deg_builder_nodes.h | 37 +- .../intern/builder/deg_builder_nodes_view_layer.cc | 25 +- .../intern/builder/deg_builder_pchanmap.h | 6 +- .../intern/builder/deg_builder_relations.cc | 193 +- .../intern/builder/deg_builder_relations.h | 75 +- .../intern/builder/deg_builder_relations_drivers.h | 6 +- .../intern/builder/deg_builder_relations_impl.h | 6 +- .../intern/builder/deg_builder_relations_keys.cc | 179 - .../builder/deg_builder_relations_view_layer.cc | 3 +- .../intern/builder/deg_builder_remove_noop.h | 6 +- .../depsgraph/intern/builder/deg_builder_rna.cc | 12 +- .../depsgraph/intern/builder/deg_builder_rna.h | 6 +- .../intern/builder/deg_builder_transitive.h | 6 +- .../blender/depsgraph/intern/builder/pipeline.cc | 2 +- source/blender/depsgraph/intern/builder/pipeline.h | 6 +- .../intern/builder/pipeline_all_objects.cc | 4 +- .../intern/builder/pipeline_all_objects.h | 6 +- .../depsgraph/intern/builder/pipeline_compositor.h | 6 +- .../depsgraph/intern/builder/pipeline_from_ids.cc | 4 +- .../depsgraph/intern/builder/pipeline_from_ids.h | 6 +- .../depsgraph/intern/builder/pipeline_render.h | 6 +- .../depsgraph/intern/builder/pipeline_view_layer.h | 6 +- source/blender/depsgraph/intern/debug/deg_debug.h | 6 +- .../intern/debug/deg_debug_relations_graphviz.cc | 1 + .../depsgraph/intern/debug/deg_time_average.h | 6 +- source/blender/depsgraph/intern/depsgraph.cc | 8 +- source/blender/depsgraph/intern/depsgraph.h | 18 +- source/blender/depsgraph/intern/depsgraph_build.cc | 10 +- .../blender/depsgraph/intern/depsgraph_physics.cc | 2 +- .../blender/depsgraph/intern/depsgraph_physics.h | 6 +- source/blender/depsgraph/intern/depsgraph_query.cc | 3 +- .../depsgraph/intern/depsgraph_query_iter.cc | 15 +- .../blender/depsgraph/intern/depsgraph_registry.h | 6 +- .../blender/depsgraph/intern/depsgraph_relation.h | 8 +- source/blender/depsgraph/intern/depsgraph_tag.cc | 97 +- source/blender/depsgraph/intern/depsgraph_tag.h | 10 +- source/blender/depsgraph/intern/depsgraph_type.h | 6 +- source/blender/depsgraph/intern/depsgraph_update.h | 6 +- source/blender/depsgraph/intern/eval/deg_eval.cc | 154 +- source/blender/depsgraph/intern/eval/deg_eval.h | 6 +- .../intern/eval/deg_eval_copy_on_write.cc | 9 +- .../depsgraph/intern/eval/deg_eval_copy_on_write.h | 6 +- .../depsgraph/intern/eval/deg_eval_flush.cc | 16 +- .../blender/depsgraph/intern/eval/deg_eval_flush.h | 6 +- .../intern/eval/deg_eval_runtime_backup.cc | 2 + .../intern/eval/deg_eval_runtime_backup.h | 6 +- .../eval/deg_eval_runtime_backup_animation.h | 6 +- .../intern/eval/deg_eval_runtime_backup_gpencil.h | 6 +- .../intern/eval/deg_eval_runtime_backup_modifier.h | 6 +- .../eval/deg_eval_runtime_backup_movieclip.h | 6 +- .../intern/eval/deg_eval_runtime_backup_object.h | 6 +- .../intern/eval/deg_eval_runtime_backup_pose.h | 6 +- .../intern/eval/deg_eval_runtime_backup_scene.h | 6 +- .../intern/eval/deg_eval_runtime_backup_sequence.h | 6 +- .../eval/deg_eval_runtime_backup_sequencer.h | 6 +- .../intern/eval/deg_eval_runtime_backup_sound.h | 6 +- .../intern/eval/deg_eval_runtime_backup_volume.h | 6 +- .../blender/depsgraph/intern/eval/deg_eval_stats.h | 6 +- .../depsgraph/intern/eval/deg_eval_visibility.cc | 232 + .../depsgraph/intern/eval/deg_eval_visibility.h | 29 + source/blender/depsgraph/intern/node/deg_node.cc | 4 + source/blender/depsgraph/intern/node/deg_node.h | 10 +- .../depsgraph/intern/node/deg_node_component.cc | 23 +- .../depsgraph/intern/node/deg_node_component.h | 55 +- .../depsgraph/intern/node/deg_node_factory.h | 7 +- .../depsgraph/intern/node/deg_node_factory_impl.h | 15 +- .../blender/depsgraph/intern/node/deg_node_id.cc | 9 +- source/blender/depsgraph/intern/node/deg_node_id.h | 23 +- .../depsgraph/intern/node/deg_node_operation.cc | 24 +- .../depsgraph/intern/node/deg_node_operation.h | 25 +- .../blender/depsgraph/intern/node/deg_node_time.h | 6 +- source/blender/draw/CMakeLists.txt | 167 +- .../draw/engines/compositor/compositor_engine.cc | 203 + .../draw/engines/compositor/compositor_engine.h | 13 + .../blender/draw/engines/eevee/eevee_cryptomatte.c | 15 +- source/blender/draw/engines/eevee/eevee_engine.c | 4 +- .../blender/draw/engines/eevee/eevee_lightcache.c | 2 +- .../blender/draw/engines/eevee/eevee_materials.c | 2 +- source/blender/draw/engines/eevee/eevee_private.h | 4 +- source/blender/draw/engines/eevee/eevee_render.c | 2 +- source/blender/draw/engines/eevee/eevee_sampling.c | 5 +- source/blender/draw/engines/eevee/eevee_shaders.c | 14 +- .../draw/engines/eevee/eevee_shadows_cascade.c | 2 +- source/blender/draw/engines/eevee/eevee_volumes.c | 11 +- .../engines/eevee/shaders/closure_type_lib.glsl | 4 +- .../engines/eevee/shaders/cryptomatte_lib.glsl | 19 + .../engines/eevee/shaders/cryptomatte_vert.glsl | 1 + .../eevee/shaders/effect_dof_resolve_frag.glsl | 2 +- .../eevee/shaders/effect_dof_scatter_frag.glsl | 2 +- .../shaders/lightprobe_filter_diffuse_frag.glsl | 2 +- .../draw/engines/eevee/shaders/prepass_frag.glsl | 14 + .../draw/engines/eevee/shaders/raytrace_lib.glsl | 3 +- .../draw/engines/eevee/shaders/shadow_vert.glsl | 4 + .../draw/engines/eevee/shaders/surface_frag.glsl | 6 +- .../draw/engines/eevee/shaders/surface_lib.glsl | 8 +- .../draw/engines/eevee/shaders/surface_vert.glsl | 4 + .../engines/eevee/shaders/volumetric_frag.glsl | 4 + .../engines/eevee/shaders/volumetric_vert.glsl | 5 + .../draw/engines/eevee_next/eevee_camera.cc | 18 +- .../draw/engines/eevee_next/eevee_camera.hh | 23 +- .../draw/engines/eevee_next/eevee_cryptomatte.cc | 132 + .../draw/engines/eevee_next/eevee_cryptomatte.hh | 68 + .../draw/engines/eevee_next/eevee_defines.hh | 80 +- .../engines/eevee_next/eevee_depth_of_field.cc | 761 +++ .../engines/eevee_next/eevee_depth_of_field.hh | 200 + .../draw/engines/eevee_next/eevee_engine.cc | 22 +- .../blender/draw/engines/eevee_next/eevee_film.cc | 362 +- .../blender/draw/engines/eevee_next/eevee_film.hh | 148 +- .../draw/engines/eevee_next/eevee_hizbuffer.cc | 99 + .../draw/engines/eevee_next/eevee_hizbuffer.hh | 88 + .../draw/engines/eevee_next/eevee_instance.cc | 190 +- .../draw/engines/eevee_next/eevee_instance.hh | 27 +- .../blender/draw/engines/eevee_next/eevee_light.cc | 488 ++ .../blender/draw/engines/eevee_next/eevee_light.hh | 169 + .../draw/engines/eevee_next/eevee_material.cc | 93 +- .../draw/engines/eevee_next/eevee_material.hh | 15 +- .../draw/engines/eevee_next/eevee_motion_blur.cc | 256 + .../draw/engines/eevee_next/eevee_motion_blur.hh | 130 + .../draw/engines/eevee_next/eevee_pipeline.cc | 304 +- .../draw/engines/eevee_next/eevee_pipeline.hh | 84 +- .../draw/engines/eevee_next/eevee_renderbuffers.cc | 84 +- .../draw/engines/eevee_next/eevee_renderbuffers.hh | 8 +- .../draw/engines/eevee_next/eevee_sampling.cc | 38 +- .../draw/engines/eevee_next/eevee_sampling.hh | 37 +- .../draw/engines/eevee_next/eevee_shader.cc | 94 +- .../draw/engines/eevee_next/eevee_shader.hh | 35 +- .../draw/engines/eevee_next/eevee_shader_shared.hh | 425 +- .../blender/draw/engines/eevee_next/eevee_sync.cc | 87 +- .../blender/draw/engines/eevee_next/eevee_sync.hh | 12 +- .../draw/engines/eevee_next/eevee_velocity.cc | 124 +- .../draw/engines/eevee_next/eevee_velocity.hh | 86 +- .../blender/draw/engines/eevee_next/eevee_view.cc | 69 +- .../blender/draw/engines/eevee_next/eevee_view.hh | 11 +- .../blender/draw/engines/eevee_next/eevee_world.cc | 4 +- .../eevee_next/shaders/eevee_attributes_lib.glsl | 42 +- .../eevee_next/shaders/eevee_camera_lib.glsl | 20 +- .../eevee_next/shaders/eevee_colorspace_lib.glsl | 37 + .../eevee_next/shaders/eevee_cryptomatte_lib.glsl | 70 + .../eevee_depth_of_field_accumulator_lib.glsl | 680 +++ .../eevee_depth_of_field_bokeh_lut_comp.glsl | 55 + .../eevee_depth_of_field_downsample_comp.glsl | 32 + .../shaders/eevee_depth_of_field_filter_comp.glsl | 163 + .../shaders/eevee_depth_of_field_gather_comp.glsl | 99 + .../eevee_depth_of_field_hole_fill_comp.glsl | 70 + .../shaders/eevee_depth_of_field_lib.glsl | 327 ++ .../shaders/eevee_depth_of_field_reduce_comp.glsl | 247 + .../shaders/eevee_depth_of_field_resolve_comp.glsl | 178 + .../shaders/eevee_depth_of_field_scatter_frag.glsl | 62 + .../shaders/eevee_depth_of_field_scatter_vert.glsl | 45 + .../shaders/eevee_depth_of_field_setup_comp.glsl | 46 + .../eevee_depth_of_field_stabilize_comp.glsl | 367 ++ .../eevee_depth_of_field_tiles_dilate_comp.glsl | 97 + .../eevee_depth_of_field_tiles_flatten_comp.glsl | 78 + .../shaders/eevee_film_cryptomatte_post_comp.glsl | 77 + .../eevee_next/shaders/eevee_film_frag.glsl | 14 +- .../engines/eevee_next/shaders/eevee_film_lib.glsl | 480 +- .../eevee_next/shaders/eevee_hiz_debug_frag.glsl | 24 + .../eevee_next/shaders/eevee_hiz_update_comp.glsl | 121 + .../shaders/eevee_light_culling_debug_frag.glsl | 54 + .../shaders/eevee_light_culling_select_comp.glsl | 62 + .../shaders/eevee_light_culling_sort_comp.glsl | 57 + .../shaders/eevee_light_culling_tile_comp.glsl | 188 + .../shaders/eevee_light_culling_zbin_comp.glsl | 56 + .../eevee_next/shaders/eevee_light_eval_lib.glsl | 129 + .../eevee_next/shaders/eevee_light_iter_lib.glsl | 72 + .../eevee_next/shaders/eevee_light_lib.glsl | 209 + .../engines/eevee_next/shaders/eevee_ltc_lib.glsl | 299 ++ .../shaders/eevee_motion_blur_dilate_comp.glsl | 115 + .../shaders/eevee_motion_blur_flatten_comp.glsl | 103 + .../shaders/eevee_motion_blur_gather_comp.glsl | 221 + .../eevee_next/shaders/eevee_motion_blur_lib.glsl | 48 + .../eevee_next/shaders/eevee_nodetree_lib.glsl | 86 +- .../eevee_next/shaders/eevee_sampling_lib.glsl | 104 + .../eevee_next/shaders/eevee_surf_depth_frag.glsl | 27 +- .../shaders/eevee_surf_forward_frag.glsl | 74 +- .../engines/eevee_next/shaders/eevee_surf_lib.glsl | 6 +- .../eevee_next/shaders/eevee_surf_world_frag.glsl | 10 +- .../eevee_next/shaders/eevee_velocity_lib.glsl | 107 +- .../shaders/eevee_velocity_resolve_comp.glsl | 58 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.../draw/engines/overlay/overlay_background.c | 114 - .../draw/engines/overlay/overlay_background.cc | 114 + .../draw/engines/overlay/overlay_edit_curve.c | 121 - .../draw/engines/overlay/overlay_edit_curve.cc | 121 + .../draw/engines/overlay/overlay_edit_curves.cc | 2 +- .../draw/engines/overlay/overlay_edit_mesh.c | 381 -- .../draw/engines/overlay/overlay_edit_mesh.cc | 382 ++ .../draw/engines/overlay/overlay_edit_text.c | 203 - .../draw/engines/overlay/overlay_edit_text.cc | 219 + .../blender/draw/engines/overlay/overlay_edit_uv.c | 590 --- .../draw/engines/overlay/overlay_edit_uv.cc | 596 +++ .../blender/draw/engines/overlay/overlay_engine.c | 748 --- .../blender/draw/engines/overlay/overlay_engine.cc | 751 +++ .../blender/draw/engines/overlay/overlay_engine.h | 8 + .../blender/draw/engines/overlay/overlay_extra.c | 1615 ------ .../blender/draw/engines/overlay/overlay_extra.cc | 1623 ++++++ .../blender/draw/engines/overlay/overlay_facing.c | 73 - .../blender/draw/engines/overlay/overlay_facing.cc | 73 + source/blender/draw/engines/overlay/overlay_fade.c | 83 - .../blender/draw/engines/overlay/overlay_fade.cc | 83 + .../blender/draw/engines/overlay/overlay_gpencil.c | 471 -- .../draw/engines/overlay/overlay_gpencil.cc | 474 ++ source/blender/draw/engines/overlay/overlay_grid.c | 306 -- .../blender/draw/engines/overlay/overlay_grid.cc | 312 ++ .../blender/draw/engines/overlay/overlay_image.c | 498 -- .../blender/draw/engines/overlay/overlay_image.cc | 500 ++ .../blender/draw/engines/overlay/overlay_lattice.c | 68 - .../draw/engines/overlay/overlay_lattice.cc | 68 + .../draw/engines/overlay/overlay_metaball.c | 132 - .../draw/engines/overlay/overlay_metaball.cc | 133 + .../draw/engines/overlay/overlay_mode_transfer.c | 144 - .../draw/engines/overlay/overlay_mode_transfer.cc | 144 + .../draw/engines/overlay/overlay_motion_path.c | 220 - .../draw/engines/overlay/overlay_motion_path.cc | 220 + .../blender/draw/engines/overlay/overlay_outline.c | 379 -- .../draw/engines/overlay/overlay_outline.cc | 378 ++ .../blender/draw/engines/overlay/overlay_paint.c | 274 - .../blender/draw/engines/overlay/overlay_paint.cc | 275 ++ .../draw/engines/overlay/overlay_particle.c | 207 - .../draw/engines/overlay/overlay_particle.cc | 207 + .../blender/draw/engines/overlay/overlay_private.h | 774 --- .../draw/engines/overlay/overlay_private.hh | 776 +++ .../blender/draw/engines/overlay/overlay_sculpt.c | 77 - .../blender/draw/engines/overlay/overlay_sculpt.cc | 77 + .../draw/engines/overlay/overlay_sculpt_curves.cc | 2 +- .../blender/draw/engines/overlay/overlay_shader.c | 1082 ---- .../blender/draw/engines/overlay/overlay_shader.cc | 1082 ++++ .../draw/engines/overlay/overlay_shader_shared.h | 3 + .../blender/draw/engines/overlay/overlay_volume.c | 53 - .../blender/draw/engines/overlay/overlay_volume.cc | 53 + .../draw/engines/overlay/overlay_wireframe.c | 360 -- .../draw/engines/overlay/overlay_wireframe.cc | 362 ++ .../shaders/infos/overlay_edit_mode_info.hh | 1 - .../overlay/shaders/overlay_antialiasing_frag.glsl | 2 +- .../overlay_armature_envelope_outline_vert.glsl | 2 +- .../shaders/overlay_edit_uv_stretching_vert.glsl | 6 +- .../engines/overlay/shaders/overlay_grid_frag.glsl | 99 +- source/blender/draw/engines/select/select_engine.c | 2 +- .../draw/engines/workbench/workbench_engine.c | 2 +- source/blender/draw/intern/DRW_gpu_wrapper.hh | 294 +- source/blender/draw/intern/DRW_render.h | 93 +- source/blender/draw/intern/draw_attributes.cc | 3 +- source/blender/draw/intern/draw_cache.c | 168 +- source/blender/draw/intern/draw_cache.h | 9 - source/blender/draw/intern/draw_cache_extract.hh | 2 - .../blender/draw/intern/draw_cache_extract_mesh.cc | 2 - .../intern/draw_cache_extract_mesh_render_data.cc | 138 +- source/blender/draw/intern/draw_cache_impl.h | 38 - .../blender/draw/intern/draw_cache_impl_curves.cc | 31 +- .../blender/draw/intern/draw_cache_impl_displist.c | 354 -- .../blender/draw/intern/draw_cache_impl_lattice.c | 6 - source/blender/draw/intern/draw_cache_impl_mesh.cc | 499 +- .../blender/draw/intern/draw_cache_impl_metaball.c | 294 -- .../draw/intern/draw_cache_impl_particles.c | 76 +- .../draw/intern/draw_cache_impl_pointcloud.c | 275 -- .../draw/intern/draw_cache_impl_pointcloud.cc | 282 ++ .../draw/intern/draw_cache_impl_subdivision.cc | 140 +- .../blender/draw/intern/draw_color_management.cc | 2 +- source/blender/draw/intern/draw_command.cc | 600 +++ source/blender/draw/intern/draw_command.hh | 534 ++ source/blender/draw/intern/draw_command_shared.hh | 87 + source/blender/draw/intern/draw_common.c | 10 +- .../draw/intern/draw_common_shader_shared.h | 2 +- source/blender/draw/intern/draw_curves.cc | 236 +- source/blender/draw/intern/draw_debug.c | 196 - source/blender/draw/intern/draw_debug.cc | 739 +++ source/blender/draw/intern/draw_debug.h | 19 +- source/blender/draw/intern/draw_debug.hh | 198 + source/blender/draw/intern/draw_defines.h | 27 + source/blender/draw/intern/draw_hair.cc | 243 +- source/blender/draw/intern/draw_hair_private.h | 6 +- source/blender/draw/intern/draw_handle.hh | 59 + source/blender/draw/intern/draw_instance_data.c | 24 +- source/blender/draw/intern/draw_instance_data.h | 2 +- source/blender/draw/intern/draw_manager.c | 101 +- source/blender/draw/intern/draw_manager.cc | 214 + source/blender/draw/intern/draw_manager.h | 51 +- source/blender/draw/intern/draw_manager.hh | 237 + source/blender/draw/intern/draw_manager_data.c | 117 +- source/blender/draw/intern/draw_manager_exec.c | 31 +- source/blender/draw/intern/draw_pass.hh | 1005 ++++ source/blender/draw/intern/draw_resource.cc | 109 + source/blender/draw/intern/draw_resource.hh | 206 + source/blender/draw/intern/draw_shader.cc | 54 +- source/blender/draw/intern/draw_shader.h | 6 + source/blender/draw/intern/draw_shader_shared.h | 249 +- source/blender/draw/intern/draw_state.h | 225 + source/blender/draw/intern/draw_subdivision.h | 1 + source/blender/draw/intern/draw_texture_pool.cc | 13 + source/blender/draw/intern/draw_texture_pool.h | 17 + source/blender/draw/intern/draw_view.c | 4 +- source/blender/draw/intern/draw_view.cc | 334 ++ source/blender/draw/intern/draw_view.hh | 94 + source/blender/draw/intern/draw_view_data.cc | 56 + source/blender/draw/intern/draw_view_data.h | 1 + source/blender/draw/intern/draw_volume.cc | 4 + .../draw/intern/mesh_extractors/extract_mesh.hh | 84 +- .../mesh_extractors/extract_mesh_ibo_edituv.cc | 105 +- .../mesh_extractors/extract_mesh_ibo_fdots.cc | 6 +- .../mesh_extractors/extract_mesh_ibo_lines.cc | 61 +- .../extract_mesh_ibo_lines_adjacency.cc | 19 +- .../extract_mesh_ibo_lines_paint_mask.cc | 12 +- .../mesh_extractors/extract_mesh_ibo_points.cc | 10 +- .../mesh_extractors/extract_mesh_ibo_tris.cc | 8 +- .../mesh_extractors/extract_mesh_vbo_attributes.cc | 39 +- .../mesh_extractors/extract_mesh_vbo_edge_fac.cc | 6 +- .../extract_mesh_vbo_edituv_stretch_angle.cc | 2 +- .../extract_mesh_vbo_edituv_stretch_area.cc | 25 +- .../mesh_extractors/extract_mesh_vbo_fdots_nor.cc | 12 +- .../mesh_extractors/extract_mesh_vbo_lnor.cc | 16 +- .../extract_mesh_vbo_mesh_analysis.cc | 19 +- .../mesh_extractors/extract_mesh_vbo_pos_nor.cc | 17 +- .../extract_mesh_vbo_sculpt_data.cc | 8 +- .../mesh_extractors/extract_mesh_vbo_vcol.cc | 387 -- .../mesh_extractors/extract_mesh_vbo_weights.cc | 8 +- .../draw/intern/shaders/common_aabb_lib.glsl | 59 + .../draw/intern/shaders/common_attribute_lib.glsl | 1 + .../draw/intern/shaders/common_debug_draw_lib.glsl | 215 + .../intern/shaders/common_debug_print_lib.glsl | 388 ++ .../intern/shaders/common_debug_shape_lib.glsl | 57 + .../draw/intern/shaders/common_intersect_lib.glsl | 466 ++ .../draw/intern/shaders/common_math_geom_lib.glsl | 144 +- .../draw/intern/shaders/common_math_lib.glsl | 14 +- .../draw/intern/shaders/common_shape_lib.glsl | 202 + .../draw/intern/shaders/common_view_lib.glsl | 17 +- .../intern/shaders/draw_command_generate_comp.glsl | 84 + .../shaders/draw_debug_draw_display_frag.glsl | 9 + .../shaders/draw_debug_draw_display_vert.glsl | 15 + .../blender/draw/intern/shaders/draw_debug_info.hh | 56 + .../shaders/draw_debug_print_display_frag.glsl | 133 + .../shaders/draw_debug_print_display_vert.glsl | 29 + .../draw/intern/shaders/draw_object_infos_info.hh | 20 + .../shaders/draw_resource_finalize_comp.glsl | 64 + .../blender/draw/intern/shaders/draw_view_info.hh | 81 +- .../draw/intern/shaders/draw_visibility_comp.glsl | 46 + source/blender/draw/tests/draw_pass_test.cc | 441 ++ source/blender/draw/tests/shaders_test.cc | 2 +- source/blender/editors/animation/CMakeLists.txt | 1 - .../editors/animation/anim_channels_defines.c | 15 +- .../blender/editors/animation/anim_channels_edit.c | 26 +- source/blender/editors/animation/anim_deps.c | 3 +- source/blender/editors/animation/anim_draw.c | 9 +- source/blender/editors/animation/anim_filter.c | 54 +- source/blender/editors/animation/anim_ipo_utils.c | 1 + source/blender/editors/animation/anim_markers.c | 135 +- source/blender/editors/animation/drivers.c | 3 +- source/blender/editors/animation/fmodifier_ui.c | 2 +- source/blender/editors/animation/keyframes_draw.c | 2 +- source/blender/editors/animation/keyframes_edit.c | 13 +- .../blender/editors/animation/keyframes_general.c | 84 +- .../blender/editors/animation/keyframes_keylist.cc | 7 +- source/blender/editors/animation/keyframing.c | 20 +- source/blender/editors/animation/keyingsets.c | 5 +- source/blender/editors/animation/time_scrub_ui.c | 6 +- source/blender/editors/armature/CMakeLists.txt | 1 - source/blender/editors/armature/armature_add.c | 11 +- source/blender/editors/armature/armature_edit.c | 27 +- source/blender/editors/armature/armature_naming.c | 18 +- .../blender/editors/armature/armature_relations.c | 5 +- source/blender/editors/armature/armature_select.c | 55 +- .../blender/editors/armature/armature_skinning.c | 8 +- .../blender/editors/armature/editarmature_undo.c | 7 +- source/blender/editors/armature/meshlaplacian.c | 30 +- source/blender/editors/armature/pose_edit.c | 16 +- source/blender/editors/armature/pose_lib.c | 8 +- source/blender/editors/armature/pose_select.c | 43 +- source/blender/editors/armature/pose_slide.c | 16 +- source/blender/editors/armature/pose_transform.c | 9 +- source/blender/editors/armature/pose_utils.c | 5 +- source/blender/editors/asset/ED_asset_handle.h | 13 + source/blender/editors/asset/ED_asset_list.h | 2 +- .../blender/editors/asset/intern/asset_handle.cc | 30 + .../blender/editors/asset/intern/asset_indexer.cc | 16 +- .../asset/intern/asset_library_reference_enum.cc | 6 +- source/blender/editors/asset/intern/asset_list.cc | 7 +- source/blender/editors/asset/intern/asset_ops.cc | 3 +- source/blender/editors/curve/CMakeLists.txt | 1 - source/blender/editors/curve/editcurve.c | 498 +- source/blender/editors/curve/editcurve_add.c | 6 +- source/blender/editors/curve/editcurve_paint.c | 2 +- source/blender/editors/curve/editcurve_pen.c | 4 +- source/blender/editors/curve/editcurve_query.c | 2 +- source/blender/editors/curve/editcurve_select.c | 98 +- source/blender/editors/curve/editcurve_undo.c | 7 +- source/blender/editors/curve/editfont.c | 83 +- source/blender/editors/curve/editfont_undo.c | 5 +- source/blender/editors/curves/CMakeLists.txt | 1 + source/blender/editors/curves/intern/curves_add.cc | 15 +- source/blender/editors/curves/intern/curves_ops.cc | 171 +- source/blender/editors/geometry/CMakeLists.txt | 1 + .../editors/geometry/geometry_attributes.cc | 18 +- .../blender/editors/gizmo_library/CMakeLists.txt | 1 - .../gizmo_library/gizmo_types/button2d_gizmo.c | 2 +- .../gizmo_library/gizmo_types/cage2d_gizmo.c | 6 +- source/blender/editors/gpencil/CMakeLists.txt | 2 +- source/blender/editors/gpencil/annotate_paint.c | 12 +- source/blender/editors/gpencil/gpencil_add_blank.c | 6 +- .../blender/editors/gpencil/gpencil_add_lineart.c | 6 +- .../blender/editors/gpencil/gpencil_add_monkey.c | 18 +- .../blender/editors/gpencil/gpencil_add_stroke.c | 18 +- source/blender/editors/gpencil/gpencil_armature.c | 13 +- .../editors/gpencil/gpencil_bake_animation.cc | 2 +- source/blender/editors/gpencil/gpencil_convert.c | 3 +- source/blender/editors/gpencil/gpencil_data.c | 7 +- source/blender/editors/gpencil/gpencil_edit.c | 565 ++- source/blender/editors/gpencil/gpencil_fill.c | 390 +- source/blender/editors/gpencil/gpencil_intern.h | 2 + .../blender/editors/gpencil/gpencil_interpolate.c | 13 +- source/blender/editors/gpencil/gpencil_mesh.cc | 4 +- source/blender/editors/gpencil/gpencil_ops.c | 2 + .../editors/gpencil/gpencil_ops_versioning.c | 2 +- source/blender/editors/gpencil/gpencil_paint.c | 103 +- source/blender/editors/gpencil/gpencil_primitive.c | 8 +- .../blender/editors/gpencil/gpencil_sculpt_paint.c | 14 +- source/blender/editors/gpencil/gpencil_select.c | 2 +- source/blender/editors/gpencil/gpencil_trace_ops.c | 31 +- source/blender/editors/gpencil/gpencil_utils.c | 19 +- .../blender/editors/gpencil/gpencil_vertex_ops.c | 2 +- source/blender/editors/include/ED_anim_api.h | 21 +- source/blender/editors/include/ED_armature.h | 9 +- source/blender/editors/include/ED_curves.h | 6 +- source/blender/editors/include/ED_curves_sculpt.h | 25 + source/blender/editors/include/ED_fileselect.h | 8 + source/blender/editors/include/ED_gpencil.h | 8 +- source/blender/editors/include/ED_image.h | 5 +- source/blender/editors/include/ED_keyframes_edit.h | 5 +- source/blender/editors/include/ED_mesh.h | 45 +- source/blender/editors/include/ED_object.h | 16 +- source/blender/editors/include/ED_paint.h | 7 +- source/blender/editors/include/ED_screen.h | 6 +- source/blender/editors/include/ED_screen_types.h | 2 +- source/blender/editors/include/ED_sculpt.h | 11 +- source/blender/editors/include/ED_space_api.h | 2 +- source/blender/editors/include/ED_transform.h | 3 +- .../include/ED_transform_snap_object_context.h | 6 +- source/blender/editors/include/ED_types.h | 27 - source/blender/editors/include/ED_undo.h | 8 +- source/blender/editors/include/ED_uvedit.h | 45 +- source/blender/editors/include/ED_view3d.h | 36 +- source/blender/editors/include/UI_abstract_view.hh | 217 +- source/blender/editors/include/UI_grid_view.hh | 35 +- source/blender/editors/include/UI_interface.h | 85 +- source/blender/editors/include/UI_interface.hh | 13 +- source/blender/editors/include/UI_resources.h | 2 + source/blender/editors/include/UI_tree_view.hh | 151 +- source/blender/editors/include/UI_view2d.h | 14 +- source/blender/editors/interface/CMakeLists.txt | 42 +- source/blender/editors/interface/abstract_view.cc | 102 - .../interface/eyedroppers/eyedropper_color.c | 554 +++ .../interface/eyedroppers/eyedropper_colorband.c | 367 ++ .../interface/eyedroppers/eyedropper_datablock.c | 378 ++ .../interface/eyedroppers/eyedropper_depth.c | 381 ++ .../interface/eyedroppers/eyedropper_driver.c | 221 + .../eyedroppers/eyedropper_gpencil_color.c | 373 ++ .../interface/eyedroppers/eyedropper_intern.h | 57 + .../interface/eyedroppers/interface_eyedropper.c | 161 + source/blender/editors/interface/grid_view.cc | 496 -- source/blender/editors/interface/interface.cc | 102 +- source/blender/editors/interface/interface_anim.c | 348 -- source/blender/editors/interface/interface_anim.cc | 355 ++ .../editors/interface/interface_context_menu.c | 18 +- source/blender/editors/interface/interface_drag.cc | 10 +- source/blender/editors/interface/interface_draw.c | 50 +- .../editors/interface/interface_dropboxes.cc | 32 +- .../editors/interface/interface_eyedropper.c | 161 - .../editors/interface/interface_eyedropper_color.c | 554 --- .../interface/interface_eyedropper_colorband.c | 367 -- .../interface/interface_eyedropper_datablock.c | 378 -- .../editors/interface/interface_eyedropper_depth.c | 381 -- .../interface/interface_eyedropper_driver.c | 220 - .../interface/interface_eyedropper_gpencil_color.c | 373 -- .../interface/interface_eyedropper_intern.h | 57 - .../blender/editors/interface/interface_handlers.c | 152 +- source/blender/editors/interface/interface_icons.c | 10 +- .../editors/interface/interface_icons_event.c | 100 +- .../blender/editors/interface/interface_intern.h | 35 +- .../blender/editors/interface/interface_layout.c | 9 +- source/blender/editors/interface/interface_ops.c | 2259 --------- source/blender/editors/interface/interface_ops.cc | 2572 ++++++++++ source/blender/editors/interface/interface_panel.c | 2602 ---------- .../blender/editors/interface/interface_panel.cc | 2581 ++++++++++ .../blender/editors/interface/interface_query.cc | 32 +- .../interface/interface_region_color_picker.cc | 4 +- .../editors/interface/interface_region_menu_pie.cc | 5 +- .../interface/interface_region_menu_popup.cc | 4 +- .../editors/interface/interface_region_popover.cc | 4 +- .../editors/interface/interface_region_popup.cc | 4 +- .../editors/interface/interface_region_search.cc | 26 +- .../editors/interface/interface_region_tooltip.c | 1558 ------ .../editors/interface/interface_region_tooltip.cc | 1476 ++++++ .../blender/editors/interface/interface_regions.cc | 4 +- .../editors/interface/interface_regions_intern.h | 25 - .../editors/interface/interface_regions_intern.hh | 18 + .../interface/interface_template_asset_view.cc | 4 +- .../interface_template_attribute_search.cc | 6 +- .../editors/interface/interface_template_list.cc | 22 +- .../interface/interface_template_search_menu.cc | 1 + .../interface/interface_template_search_operator.c | 129 - .../interface_template_search_operator.cc | 131 + .../editors/interface/interface_templates.c | 209 +- source/blender/editors/interface/interface_undo.c | 112 - source/blender/editors/interface/interface_undo.cc | 113 + .../blender/editors/interface/interface_utils.cc | 2 +- source/blender/editors/interface/interface_view.cc | 191 - .../blender/editors/interface/interface_widgets.c | 96 +- source/blender/editors/interface/resources.c | 6 + source/blender/editors/interface/tree_view.cc | 838 ---- source/blender/editors/interface/view2d.cc | 91 +- source/blender/editors/interface/view2d_draw.cc | 2 +- source/blender/editors/interface/view2d_ops.cc | 6 +- .../editors/interface/views/abstract_view.cc | 109 + .../editors/interface/views/abstract_view_item.cc | 373 ++ .../blender/editors/interface/views/grid_view.cc | 463 ++ .../editors/interface/views/interface_view.cc | 196 + .../blender/editors/interface/views/tree_view.cc | 555 +++ source/blender/editors/io/CMakeLists.txt | 6 +- source/blender/editors/io/io_alembic.c | 40 +- source/blender/editors/io/io_collada.c | 32 +- source/blender/editors/io/io_gpencil_export.c | 32 +- source/blender/editors/io/io_gpencil_import.c | 45 +- source/blender/editors/io/io_obj.c | 176 +- source/blender/editors/io/io_stl_ops.c | 4 +- source/blender/editors/io/io_usd.c | 48 +- .../blender/editors/lattice/editlattice_select.c | 24 +- source/blender/editors/lattice/editlattice_tools.c | 6 +- source/blender/editors/lattice/editlattice_undo.c | 9 +- source/blender/editors/mask/CMakeLists.txt | 1 - source/blender/editors/mask/mask_draw.c | 10 +- source/blender/editors/mask/mask_query.c | 3 +- source/blender/editors/mask/mask_shapekey.c | 4 +- source/blender/editors/mesh/CMakeLists.txt | 1 - source/blender/editors/mesh/editface.cc | 287 +- source/blender/editors/mesh/editmesh_bevel.c | 4 +- source/blender/editors/mesh/editmesh_bisect.c | 5 +- source/blender/editors/mesh/editmesh_extrude.c | 24 +- .../blender/editors/mesh/editmesh_extrude_screw.c | 9 +- .../blender/editors/mesh/editmesh_extrude_spin.c | 3 +- source/blender/editors/mesh/editmesh_inset.c | 2 +- source/blender/editors/mesh/editmesh_intersect.c | 9 +- source/blender/editors/mesh/editmesh_knife.c | 23 +- .../blender/editors/mesh/editmesh_knife_project.c | 2 +- source/blender/editors/mesh/editmesh_loopcut.c | 4 +- .../blender/editors/mesh/editmesh_mask_extract.c | 8 +- source/blender/editors/mesh/editmesh_path.c | 16 +- source/blender/editors/mesh/editmesh_polybuild.c | 40 +- source/blender/editors/mesh/editmesh_rip.c | 3 +- source/blender/editors/mesh/editmesh_rip_edge.c | 3 +- source/blender/editors/mesh/editmesh_select.c | 80 +- .../blender/editors/mesh/editmesh_select_similar.c | 12 +- source/blender/editors/mesh/editmesh_tools.c | 194 +- source/blender/editors/mesh/editmesh_undo.c | 16 +- source/blender/editors/mesh/editmesh_utils.c | 704 ++- source/blender/editors/mesh/mesh_data.cc | 547 +- source/blender/editors/mesh/mesh_intern.h | 14 +- source/blender/editors/mesh/mesh_mirror.c | 13 +- source/blender/editors/mesh/mesh_ops.c | 8 +- source/blender/editors/mesh/meshtools.cc | 139 +- source/blender/editors/metaball/editmball_undo.c | 7 +- source/blender/editors/metaball/mball_edit.c | 27 +- source/blender/editors/object/CMakeLists.txt | 4 +- source/blender/editors/object/object_add.cc | 133 +- source/blender/editors/object/object_bake.c | 5 +- source/blender/editors/object/object_bake_api.c | 133 +- source/blender/editors/object/object_collection.c | 4 +- source/blender/editors/object/object_constraint.c | 17 +- .../blender/editors/object/object_data_transfer.c | 8 +- .../blender/editors/object/object_data_transform.c | 2 +- source/blender/editors/object/object_edit.c | 73 +- source/blender/editors/object/object_facemap_ops.c | 2 +- .../editors/object/object_gpencil_modifier.c | 3 +- source/blender/editors/object/object_hook.c | 18 +- source/blender/editors/object/object_intern.h | 8 +- source/blender/editors/object/object_modes.c | 10 +- source/blender/editors/object/object_modifier.cc | 88 +- source/blender/editors/object/object_ops.c | 5 +- source/blender/editors/object/object_random.c | 4 +- source/blender/editors/object/object_relations.c | 200 +- source/blender/editors/object/object_remesh.cc | 53 +- source/blender/editors/object/object_select.c | 72 +- source/blender/editors/object/object_shader_fx.c | 9 +- source/blender/editors/object/object_shapekey.c | 46 +- source/blender/editors/object/object_transform.cc | 7 +- source/blender/editors/object/object_utils.c | 9 +- source/blender/editors/object/object_vgroup.c | 4564 ----------------- source/blender/editors/object/object_vgroup.cc | 4614 +++++++++++++++++ source/blender/editors/physics/CMakeLists.txt | 1 - source/blender/editors/physics/dynamicpaint_ops.c | 3 +- source/blender/editors/physics/particle_edit.c | 31 +- .../blender/editors/physics/particle_edit_undo.c | 7 +- source/blender/editors/physics/particle_object.c | 12 +- source/blender/editors/physics/physics_fluid.c | 1 + .../blender/editors/physics/rigidbody_constraint.c | 9 +- source/blender/editors/render/CMakeLists.txt | 1 - source/blender/editors/render/render_internal.cc | 8 +- source/blender/editors/render/render_opengl.cc | 58 +- source/blender/editors/render/render_preview.cc | 78 +- source/blender/editors/render/render_shading.cc | 26 +- source/blender/editors/render/render_update.cc | 26 +- source/blender/editors/render/render_view.cc | 12 +- source/blender/editors/scene/scene_edit.c | 2 +- source/blender/editors/screen/CMakeLists.txt | 1 - source/blender/editors/screen/area.c | 43 +- source/blender/editors/screen/glutil.c | 7 +- source/blender/editors/screen/screen_context.c | 175 +- source/blender/editors/screen/screen_draw.c | 6 +- source/blender/editors/screen/screen_edit.c | 17 +- source/blender/editors/screen/screen_geometry.c | 2 +- source/blender/editors/screen/screen_intern.h | 2 +- source/blender/editors/screen/screen_ops.c | 27 +- source/blender/editors/screen/screen_user_menu.c | 10 +- source/blender/editors/screen/screendump.c | 3 +- source/blender/editors/screen/workspace_edit.c | 23 +- source/blender/editors/sculpt_paint/CMakeLists.txt | 5 +- .../editors/sculpt_paint/curves_sculpt_add.cc | 277 +- .../editors/sculpt_paint/curves_sculpt_brush.cc | 93 +- .../editors/sculpt_paint/curves_sculpt_comb.cc | 107 +- .../editors/sculpt_paint/curves_sculpt_delete.cc | 39 +- .../editors/sculpt_paint/curves_sculpt_density.cc | 422 +- .../sculpt_paint/curves_sculpt_grow_shrink.cc | 102 +- .../editors/sculpt_paint/curves_sculpt_intern.hh | 35 +- .../editors/sculpt_paint/curves_sculpt_ops.cc | 91 +- .../editors/sculpt_paint/curves_sculpt_pinch.cc | 46 +- .../editors/sculpt_paint/curves_sculpt_puff.cc | 54 +- .../sculpt_paint/curves_sculpt_selection.cc | 54 +- .../sculpt_paint/curves_sculpt_selection_paint.cc | 25 +- .../editors/sculpt_paint/curves_sculpt_slide.cc | 485 +- .../editors/sculpt_paint/curves_sculpt_smooth.cc | 106 +- .../sculpt_paint/curves_sculpt_snake_hook.cc | 48 +- source/blender/editors/sculpt_paint/paint_cursor.c | 27 +- source/blender/editors/sculpt_paint/paint_hide.c | 22 +- source/blender/editors/sculpt_paint/paint_image.cc | 23 +- .../blender/editors/sculpt_paint/paint_image_2d.c | 2 +- .../editors/sculpt_paint/paint_image_ops_paint.cc | 6 +- .../editors/sculpt_paint/paint_image_proj.c | 45 +- source/blender/editors/sculpt_paint/paint_intern.h | 9 +- source/blender/editors/sculpt_paint/paint_mask.c | 69 +- source/blender/editors/sculpt_paint/paint_ops.c | 30 +- source/blender/editors/sculpt_paint/paint_stroke.c | 54 +- source/blender/editors/sculpt_paint/paint_utils.c | 86 +- .../blender/editors/sculpt_paint/paint_vertex.cc | 143 +- .../editors/sculpt_paint/paint_vertex_color_ops.cc | 24 +- .../editors/sculpt_paint/paint_vertex_weight_ops.c | 69 +- .../sculpt_paint/paint_vertex_weight_utils.c | 2 +- source/blender/editors/sculpt_paint/sculpt.c | 706 +-- .../editors/sculpt_paint/sculpt_automasking.cc | 95 +- .../blender/editors/sculpt_paint/sculpt_boundary.c | 321 +- .../editors/sculpt_paint/sculpt_brush_types.c | 146 +- source/blender/editors/sculpt_paint/sculpt_cloth.c | 73 +- .../blender/editors/sculpt_paint/sculpt_detail.c | 12 +- .../blender/editors/sculpt_paint/sculpt_dyntopo.c | 60 +- .../blender/editors/sculpt_paint/sculpt_expand.c | 377 +- .../blender/editors/sculpt_paint/sculpt_face_set.c | 1448 ------ .../editors/sculpt_paint/sculpt_face_set.cc | 1463 ++++++ .../editors/sculpt_paint/sculpt_filter_color.c | 21 +- .../editors/sculpt_paint/sculpt_filter_mask.c | 29 +- .../editors/sculpt_paint/sculpt_filter_mesh.c | 42 +- .../blender/editors/sculpt_paint/sculpt_geodesic.c | 80 +- .../blender/editors/sculpt_paint/sculpt_intern.h | 169 +- .../editors/sculpt_paint/sculpt_mask_expand.c | 58 +- .../editors/sculpt_paint/sculpt_mask_init.c | 4 +- .../sculpt_paint/sculpt_multiplane_scrape.c | 6 +- source/blender/editors/sculpt_paint/sculpt_ops.c | 299 +- .../editors/sculpt_paint/sculpt_paint_color.c | 73 +- .../editors/sculpt_paint/sculpt_paint_image.cc | 12 +- source/blender/editors/sculpt_paint/sculpt_pose.c | 108 +- .../blender/editors/sculpt_paint/sculpt_smooth.c | 87 +- .../editors/sculpt_paint/sculpt_transform.c | 18 +- source/blender/editors/sculpt_paint/sculpt_undo.c | 212 +- source/blender/editors/sculpt_paint/sculpt_uv.c | 438 +- source/blender/editors/sound/sound_ops.c | 15 +- source/blender/editors/space_action/CMakeLists.txt | 1 - source/blender/editors/space_action/action_data.c | 5 +- source/blender/editors/space_action/action_draw.c | 4 +- source/blender/editors/space_action/action_edit.c | 18 +- .../blender/editors/space_action/action_select.c | 11 +- source/blender/editors/space_action/space_action.c | 16 +- source/blender/editors/space_api/spacetypes.c | 1 + .../blender/editors/space_buttons/CMakeLists.txt | 3 +- .../editors/space_buttons/buttons_context.c | 19 +- .../blender/editors/space_buttons/buttons_intern.h | 2 +- source/blender/editors/space_buttons/buttons_ops.c | 6 + .../editors/space_buttons/buttons_texture.c | 3 +- .../blender/editors/space_buttons/space_buttons.c | 11 +- source/blender/editors/space_clip/CMakeLists.txt | 1 - source/blender/editors/space_clip/clip_buttons.c | 2 +- .../editors/space_clip/clip_dopesheet_draw.c | 4 +- source/blender/editors/space_clip/clip_draw.c | 26 +- .../blender/editors/space_clip/clip_graph_draw.c | 2 +- source/blender/editors/space_clip/clip_utils.c | 2 +- source/blender/editors/space_clip/space_clip.c | 16 +- source/blender/editors/space_clip/tracking_ops.c | 1 + .../editors/space_clip/tracking_ops_orient.c | 7 +- .../blender/editors/space_console/CMakeLists.txt | 1 - .../blender/editors/space_console/console_draw.c | 2 +- .../blender/editors/space_console/console_intern.h | 2 +- source/blender/editors/space_console/console_ops.c | 14 +- .../blender/editors/space_console/space_console.c | 11 +- source/blender/editors/space_file/CMakeLists.txt | 4 +- .../editors/space_file/asset_catalog_tree_view.cc | 58 +- source/blender/editors/space_file/file_draw.c | 14 +- source/blender/editors/space_file/file_intern.h | 23 +- source/blender/editors/space_file/file_ops.c | 176 +- source/blender/editors/space_file/filelist.c | 4121 ---------------- source/blender/editors/space_file/filelist.cc | 3956 +++++++++++++++ source/blender/editors/space_file/filelist.h | 11 - source/blender/editors/space_file/filesel.c | 30 +- .../blender/editors/space_file/folder_history.cc | 191 + source/blender/editors/space_file/fsmenu.c | 21 +- source/blender/editors/space_file/fsmenu.h | 7 +- source/blender/editors/space_file/space_file.c | 8 +- source/blender/editors/space_graph/CMakeLists.txt | 1 - source/blender/editors/space_graph/graph_buttons.c | 11 +- source/blender/editors/space_graph/graph_draw.c | 16 +- source/blender/editors/space_graph/graph_edit.c | 20 +- source/blender/editors/space_graph/graph_select.c | 9 +- source/blender/editors/space_graph/space_graph.c | 11 +- source/blender/editors/space_image/CMakeLists.txt | 3 +- source/blender/editors/space_image/image_buttons.c | 10 +- source/blender/editors/space_image/image_draw.c | 37 +- source/blender/editors/space_image/image_edit.c | 14 +- source/blender/editors/space_image/image_ops.c | 58 +- source/blender/editors/space_image/image_undo.c | 1093 ---- source/blender/editors/space_image/image_undo.cc | 1137 +++++ source/blender/editors/space_image/space_image.c | 24 +- source/blender/editors/space_info/CMakeLists.txt | 1 - source/blender/editors/space_info/info_stats.cc | 83 +- source/blender/editors/space_info/space_info.c | 6 +- source/blender/editors/space_info/textview.c | 4 +- source/blender/editors/space_nla/CMakeLists.txt | 1 - source/blender/editors/space_nla/nla_buttons.c | 11 +- source/blender/editors/space_nla/nla_channels.c | 6 +- source/blender/editors/space_nla/nla_draw.c | 42 +- source/blender/editors/space_nla/nla_edit.c | 66 +- source/blender/editors/space_nla/nla_ops.c | 24 + source/blender/editors/space_nla/nla_select.c | 2 +- source/blender/editors/space_nla/space_nla.c | 14 +- source/blender/editors/space_node/CMakeLists.txt | 6 +- .../blender/editors/space_node/add_node_search.cc | 312 ++ source/blender/editors/space_node/drawnode.cc | 582 ++- .../blender/editors/space_node/link_drag_search.cc | 177 +- source/blender/editors/space_node/node_add.cc | 348 +- .../editors/space_node/node_context_path.cc | 31 +- source/blender/editors/space_node/node_draw.cc | 586 +-- source/blender/editors/space_node/node_edit.cc | 235 +- .../space_node/node_geometry_attribute_search.cc | 65 +- source/blender/editors/space_node/node_gizmo.cc | 45 +- source/blender/editors/space_node/node_group.cc | 43 +- source/blender/editors/space_node/node_intern.hh | 53 +- source/blender/editors/space_node/node_ops.cc | 5 +- .../editors/space_node/node_relationships.cc | 533 +- source/blender/editors/space_node/node_select.cc | 248 +- .../blender/editors/space_node/node_templates.cc | 67 +- source/blender/editors/space_node/node_view.cc | 22 +- source/blender/editors/space_node/space_node.cc | 16 +- .../blender/editors/space_outliner/CMakeLists.txt | 3 +- .../editors/space_outliner/outliner_collections.cc | 158 +- .../editors/space_outliner/outliner_context.cc | 4 +- .../editors/space_outliner/outliner_dragdrop.cc | 77 +- .../editors/space_outliner/outliner_draw.cc | 189 +- .../editors/space_outliner/outliner_edit.cc | 164 +- .../editors/space_outliner/outliner_intern.hh | 115 +- .../blender/editors/space_outliner/outliner_ops.cc | 5 + .../editors/space_outliner/outliner_query.cc | 4 +- .../editors/space_outliner/outliner_select.cc | 177 +- .../editors/space_outliner/outliner_sync.cc | 42 +- .../editors/space_outliner/outliner_tools.cc | 1403 ++++-- .../editors/space_outliner/outliner_tree.cc | 152 +- .../editors/space_outliner/outliner_utils.cc | 39 +- .../editors/space_outliner/space_outliner.cc | 37 +- .../blender/editors/space_outliner/tree/common.cc | 6 +- .../blender/editors/space_outliner/tree/common.hh | 4 + .../editors/space_outliner/tree/tree_display.cc | 5 + .../editors/space_outliner/tree/tree_display.hh | 16 +- .../space_outliner/tree/tree_display_data.cc | 5 + .../tree_display_override_library_hierarchies.cc | 89 +- .../space_outliner/tree/tree_display_view_layer.cc | 5 +- .../editors/space_outliner/tree/tree_element.cc | 43 +- .../editors/space_outliner/tree/tree_element.hh | 24 +- .../space_outliner/tree/tree_element_anim_data.hh | 2 - .../space_outliner/tree/tree_element_driver.hh | 2 - .../space_outliner/tree/tree_element_label.cc | 36 + .../space_outliner/tree/tree_element_label.hh | 36 + .../space_outliner/tree/tree_element_overrides.cc | 393 +- .../space_outliner/tree/tree_element_overrides.hh | 40 +- .../space_outliner/tree/tree_element_rna.cc | 15 +- .../editors/space_outliner/tree/tree_iterator.hh | 4 +- source/blender/editors/space_script/CMakeLists.txt | 1 - source/blender/editors/space_script/script_edit.c | 2 +- source/blender/editors/space_script/space_script.c | 2 +- .../blender/editors/space_sequencer/CMakeLists.txt | 1 - .../editors/space_sequencer/sequencer_drag_drop.c | 295 +- .../editors/space_sequencer/sequencer_draw.c | 547 +- .../editors/space_sequencer/sequencer_edit.c | 28 +- .../editors/space_sequencer/sequencer_scopes.c | 2 +- .../editors/space_sequencer/sequencer_view.c | 12 +- .../editors/space_sequencer/space_sequencer.c | 12 +- .../editors/space_spreadsheet/CMakeLists.txt | 1 - .../editors/space_spreadsheet/space_spreadsheet.cc | 8 +- .../spreadsheet_data_source_geometry.cc | 233 +- .../spreadsheet_data_source_geometry.hh | 4 - .../space_spreadsheet/spreadsheet_dataset_draw.cc | 2 +- .../editors/space_spreadsheet/spreadsheet_draw.cc | 2 +- .../space_spreadsheet/spreadsheet_layout.cc | 4 +- .../space_spreadsheet/spreadsheet_row_filter.cc | 9 +- .../blender/editors/space_statusbar/CMakeLists.txt | 1 - .../editors/space_statusbar/space_statusbar.c | 4 +- source/blender/editors/space_text/CMakeLists.txt | 1 - source/blender/editors/space_text/space_text.c | 7 +- .../blender/editors/space_text/text_autocomplete.c | 2 +- source/blender/editors/space_text/text_draw.c | 24 +- source/blender/editors/space_text/text_format_py.c | 2 +- source/blender/editors/space_text/text_ops.c | 19 +- source/blender/editors/space_topbar/CMakeLists.txt | 1 - source/blender/editors/space_topbar/space_topbar.c | 6 +- .../editors/space_userpref/space_userpref.c | 2 +- source/blender/editors/space_view3d/CMakeLists.txt | 5 +- source/blender/editors/space_view3d/drawobject.c | 25 +- source/blender/editors/space_view3d/space_view3d.c | 40 +- .../blender/editors/space_view3d/view3d_buttons.c | 32 +- .../editors/space_view3d/view3d_cursor_snap.c | 151 +- source/blender/editors/space_view3d/view3d_draw.c | 29 +- source/blender/editors/space_view3d/view3d_edit.c | 6 +- .../editors/space_view3d/view3d_gizmo_armature.c | 14 +- .../editors/space_view3d/view3d_gizmo_camera.c | 20 +- .../editors/space_view3d/view3d_gizmo_empty.c | 8 +- .../editors/space_view3d/view3d_gizmo_forcefield.c | 8 +- .../editors/space_view3d/view3d_gizmo_light.c | 24 +- .../space_view3d/view3d_gizmo_preselect_type.c | 17 +- .../editors/space_view3d/view3d_gizmo_ruler.c | 8 +- .../blender/editors/space_view3d/view3d_header.c | 9 +- .../blender/editors/space_view3d/view3d_intern.h | 10 +- .../editors/space_view3d/view3d_iterators.c | 27 +- .../blender/editors/space_view3d/view3d_navigate.c | 112 +- .../blender/editors/space_view3d/view3d_navigate.h | 24 + .../editors/space_view3d/view3d_navigate_dolly.c | 3 +- .../editors/space_view3d/view3d_navigate_fly.c | 8 +- .../editors/space_view3d/view3d_navigate_move.c | 3 +- .../editors/space_view3d/view3d_navigate_ndof.c | 7 +- .../editors/space_view3d/view3d_navigate_roll.c | 13 +- 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source/blender/gpu/GPU_storage_buffer.h | 7 + source/blender/gpu/GPU_texture.h | 8 +- source/blender/gpu/GPU_vertex_buffer.h | 16 +- source/blender/gpu/intern/gpu_backend.hh | 1 + source/blender/gpu/intern/gpu_batch.cc | 50 + source/blender/gpu/intern/gpu_batch_private.hh | 5 + source/blender/gpu/intern/gpu_buffers.c | 106 +- source/blender/gpu/intern/gpu_capabilities.cc | 25 + .../blender/gpu/intern/gpu_capabilities_private.hh | 1 + source/blender/gpu/intern/gpu_codegen.cc | 96 +- source/blender/gpu/intern/gpu_context.cc | 53 +- source/blender/gpu/intern/gpu_context_private.hh | 28 +- source/blender/gpu/intern/gpu_framebuffer.cc | 5 + .../blender/gpu/intern/gpu_framebuffer_private.hh | 4 +- source/blender/gpu/intern/gpu_immediate.cc | 3 - source/blender/gpu/intern/gpu_immediate_private.hh | 6 +- source/blender/gpu/intern/gpu_immediate_util.c | 6 +- source/blender/gpu/intern/gpu_index_buffer.cc | 105 +- .../blender/gpu/intern/gpu_index_buffer_private.hh | 21 +- 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+- source/blender/gpu/intern/gpu_texture_private.hh | 8 +- .../gpu/intern/gpu_uniform_buffer_private.hh | 2 +- source/blender/gpu/intern/gpu_vertex_buffer.cc | 22 +- .../gpu/intern/gpu_vertex_buffer_private.hh | 12 +- source/blender/gpu/intern/gpu_vertex_format.cc | 119 +- .../blender/gpu/intern/gpu_vertex_format_private.h | 1 + .../gpu/metal/kernels/compute_texture_read.msl | 2 +- .../gpu/metal/kernels/compute_texture_update.msl | 16 - .../metal/kernels/depth_2d_update_float_frag.glsl | 5 - .../gpu/metal/kernels/depth_2d_update_info.hh | 35 + .../metal/kernels/depth_2d_update_int24_frag.glsl | 4 - .../metal/kernels/depth_2d_update_int32_frag.glsl | 5 - .../gpu/metal/kernels/depth_2d_update_vert.glsl | 6 - .../kernels/gpu_shader_fullscreen_blit_frag.glsl | 5 - .../kernels/gpu_shader_fullscreen_blit_info.hh | 23 + .../kernels/gpu_shader_fullscreen_blit_vert.glsl | 8 - source/blender/gpu/metal/mtl_backend.hh | 6 +- source/blender/gpu/metal/mtl_backend.mm | 25 +- source/blender/gpu/metal/mtl_capabilities.hh | 2 + source/blender/gpu/metal/mtl_command_buffer.mm | 16 +- source/blender/gpu/metal/mtl_common.hh | 2 + source/blender/gpu/metal/mtl_context.hh | 53 +- source/blender/gpu/metal/mtl_context.mm | 209 +- source/blender/gpu/metal/mtl_framebuffer.hh | 36 +- source/blender/gpu/metal/mtl_framebuffer.mm | 20 +- source/blender/gpu/metal/mtl_index_buffer.hh | 80 + source/blender/gpu/metal/mtl_index_buffer.mm | 517 ++ source/blender/gpu/metal/mtl_memory.hh | 24 +- source/blender/gpu/metal/mtl_memory.mm | 61 +- source/blender/gpu/metal/mtl_primitive.hh | 100 + .../blender/gpu/metal/mtl_pso_descriptor_state.hh | 250 + source/blender/gpu/metal/mtl_query.hh | 41 + source/blender/gpu/metal/mtl_query.mm | 122 + source/blender/gpu/metal/mtl_shader.hh | 1165 +++++ source/blender/gpu/metal/mtl_shader.mm | 1266 +++++ source/blender/gpu/metal/mtl_shader_generator.hh | 727 +++ source/blender/gpu/metal/mtl_shader_generator.mm | 2980 +++++++++++ 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source/blender/modifiers/intern/MOD_ocean.c | 147 +- .../modifiers/intern/MOD_particleinstance.c | 32 +- .../blender/modifiers/intern/MOD_particlesystem.cc | 9 +- source/blender/modifiers/intern/MOD_remesh.c | 27 +- source/blender/modifiers/intern/MOD_screw.c | 123 +- source/blender/modifiers/intern/MOD_shapekey.c | 13 +- source/blender/modifiers/intern/MOD_shrinkwrap.c | 19 +- source/blender/modifiers/intern/MOD_simpledeform.c | 17 +- source/blender/modifiers/intern/MOD_skin.c | 37 +- source/blender/modifiers/intern/MOD_smooth.c | 18 +- source/blender/modifiers/intern/MOD_softbody.c | 4 +- source/blender/modifiers/intern/MOD_solidify.c | 6 +- .../modifiers/intern/MOD_solidify_extrude.c | 223 +- .../modifiers/intern/MOD_solidify_nonmanifold.c | 218 +- source/blender/modifiers/intern/MOD_subsurf.c | 6 +- source/blender/modifiers/intern/MOD_surface.c | 8 +- .../blender/modifiers/intern/MOD_surfacedeform.c | 42 +- source/blender/modifiers/intern/MOD_triangulate.c | 4 +- source/blender/modifiers/intern/MOD_util.c | 21 +- source/blender/modifiers/intern/MOD_util.h | 3 +- source/blender/modifiers/intern/MOD_uvproject.c | 31 +- source/blender/modifiers/intern/MOD_uvwarp.c | 29 +- .../modifiers/intern/MOD_volume_displace.cc | 4 +- .../blender/modifiers/intern/MOD_volume_to_mesh.cc | 8 +- source/blender/modifiers/intern/MOD_warp.c | 16 +- source/blender/modifiers/intern/MOD_wave.c | 43 +- .../blender/modifiers/intern/MOD_weighted_normal.c | 96 +- source/blender/modifiers/intern/MOD_weightvgedit.c | 26 +- source/blender/modifiers/intern/MOD_weightvgmix.c | 22 +- .../modifiers/intern/MOD_weightvgproximity.c | 16 +- source/blender/modifiers/intern/MOD_weld.cc | 6 +- source/blender/modifiers/intern/MOD_wireframe.c | 6 +- source/blender/nodes/CMakeLists.txt | 22 +- source/blender/nodes/NOD_composite.h | 2 +- source/blender/nodes/NOD_derived_node_tree.hh | 172 +- source/blender/nodes/NOD_geometry.h | 17 +- source/blender/nodes/NOD_geometry_exec.hh | 213 +- 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.../geometry/nodes/node_geo_duplicate_elements.cc | 279 +- .../nodes/node_geo_edge_paths_to_curves.cc | 110 + .../nodes/node_geo_edge_paths_to_selection.cc | 134 + .../nodes/geometry/nodes/node_geo_edge_split.cc | 23 +- .../nodes/geometry/nodes/node_geo_extrude_mesh.cc | 204 +- .../geometry/nodes/node_geo_field_at_index.cc | 47 +- .../geometry/nodes/node_geo_field_on_domain.cc | 146 - .../nodes/geometry/nodes/node_geo_flip_faces.cc | 25 +- .../nodes/node_geo_geometry_to_instance.cc | 2 +- .../geometry/nodes/node_geo_input_curve_handles.cc | 20 +- .../nodes/node_geo_input_instance_rotation.cc | 22 +- .../nodes/node_geo_input_instance_scale.cc | 22 +- .../nodes/node_geo_input_mesh_edge_angle.cc | 78 +- .../nodes/node_geo_input_mesh_edge_neighbors.cc | 28 +- .../nodes/node_geo_input_mesh_edge_vertices.cc | 64 +- .../nodes/node_geo_input_mesh_face_area.cc | 32 +- .../nodes/node_geo_input_mesh_face_is_planar.cc | 48 +- .../nodes/node_geo_input_mesh_face_neighbors.cc | 66 +- .../geometry/nodes/node_geo_input_mesh_island.cc | 53 +- .../nodes/node_geo_input_mesh_vertex_neighbors.cc | 58 +- .../nodes/node_geo_input_named_attribute.cc | 2 +- .../nodes/node_geo_input_shortest_edge_paths.cc | 236 + .../geometry/nodes/node_geo_input_spline_length.cc | 23 +- .../nodes/geometry/nodes/node_geo_input_tangent.cc | 25 +- .../geometry/nodes/node_geo_instance_on_points.cc | 7 +- .../geometry/nodes/node_geo_instances_to_points.cc | 42 +- .../geometry/nodes/node_geo_interpolate_domain.cc | 167 + .../nodes/geometry/nodes/node_geo_join_geometry.cc | 3 +- .../geometry/nodes/node_geo_material_selection.cc | 38 +- .../geometry/nodes/node_geo_merge_by_distance.cc | 40 +- .../nodes/node_geo_mesh_face_set_boundaries.cc | 89 + .../nodes/node_geo_mesh_primitive_circle.cc | 8 +- .../geometry/nodes/node_geo_mesh_primitive_cone.cc | 24 +- .../geometry/nodes/node_geo_mesh_primitive_grid.cc | 10 +- .../geometry/nodes/node_geo_mesh_primitive_line.cc | 5 +- .../nodes/node_geo_mesh_primitive_uv_sphere.cc | 154 +- .../nodes/geometry/nodes/node_geo_mesh_to_curve.cc | 19 +- .../geometry/nodes/node_geo_mesh_to_points.cc | 52 +- .../geometry/nodes/node_geo_mesh_to_volume.cc | 5 +- .../nodes/geometry/nodes/node_geo_object_info.cc | 2 +- .../nodes/geometry/nodes/node_geo_points.cc | 9 +- .../geometry/nodes/node_geo_points_to_vertices.cc | 46 +- .../geometry/nodes/node_geo_points_to_volume.cc | 9 +- .../nodes/geometry/nodes/node_geo_raycast.cc | 8 +- .../geometry/nodes/node_geo_remove_attribute.cc | 2 +- .../geometry/nodes/node_geo_rotate_instances.cc | 6 +- .../geometry/nodes/node_geo_scale_elements.cc | 158 +- .../geometry/nodes/node_geo_scale_instances.cc | 5 +- .../geometry/nodes/node_geo_set_curve_handles.cc | 37 +- .../geometry/nodes/node_geo_set_curve_radius.cc | 23 +- .../geometry/nodes/node_geo_set_curve_tilt.cc | 24 +- .../nodes/geometry/nodes/node_geo_set_id.cc | 2 +- .../nodes/geometry/nodes/node_geo_set_material.cc | 13 +- .../geometry/nodes/node_geo_set_material_index.cc | 20 +- .../geometry/nodes/node_geo_set_point_radius.cc | 20 +- .../nodes/geometry/nodes/node_geo_set_position.cc | 9 +- .../geometry/nodes/node_geo_set_shade_smooth.cc | 29 +- .../geometry/nodes/node_geo_set_spline_cyclic.cc | 24 +- .../nodes/node_geo_set_spline_resolution.cc | 28 +- .../nodes/node_geo_store_named_attribute.cc | 75 +- .../nodes/geometry/nodes/node_geo_string_join.cc | 5 +- .../geometry/nodes/node_geo_subdivision_surface.cc | 22 +- .../geometry/nodes/node_geo_transfer_attribute.cc | 60 +- .../nodes/geometry/nodes/node_geo_transform.cc | 129 +- .../geometry/nodes/node_geo_translate_instances.cc | 5 +- .../nodes/geometry/nodes/node_geo_triangulate.cc | 9 +- .../geometry/nodes/node_geo_uv_pack_islands.cc | 44 +- .../nodes/geometry/nodes/node_geo_uv_unwrap.cc | 49 +- .../nodes/geometry/nodes/node_geo_volume_cube.cc | 21 +- .../geometry/nodes/node_geo_volume_to_mesh.cc | 15 +- source/blender/nodes/intern/derived_node_tree.cc | 139 +- .../nodes/intern/geometry_nodes_eval_log.cc | 508 -- .../nodes/intern/geometry_nodes_lazy_function.cc | 1423 ++++++ source/blender/nodes/intern/geometry_nodes_log.cc | 610 +++ source/blender/nodes/intern/node_common.cc | 28 +- source/blender/nodes/intern/node_geometry_exec.cc | 88 +- source/blender/nodes/intern/node_multi_function.cc | 26 +- source/blender/nodes/intern/node_tree_ref.cc | 678 --- source/blender/nodes/intern/node_util.c | 2 +- source/blender/nodes/shader/CMakeLists.txt | 27 +- source/blender/nodes/shader/node_shader_tree.cc | 31 +- source/blender/nodes/shader/node_shader_util.hh | 2 + .../nodes/shader/nodes/node_shader_attribute.cc | 16 +- .../nodes/node_shader_bsdf_hair_principled.cc | 3 +- .../shader/nodes/node_shader_bsdf_principled.cc | 21 + .../nodes/shader/nodes/node_shader_color_ramp.cc | 2 +- .../nodes/shader/nodes/node_shader_curves.cc | 6 +- .../nodes/shader/nodes/node_shader_geometry.cc | 5 +- .../nodes/shader/nodes/node_shader_hair_info.cc | 4 +- .../blender/nodes/shader/nodes/node_shader_math.cc | 7 +- .../blender/nodes/shader/nodes/node_shader_mix.cc | 443 ++ .../nodes/shader/nodes/node_shader_mix_rgb.cc | 33 +- .../blender/nodes/shader/nodes/node_shader_rgb.cc | 7 +- .../nodes/shader/nodes/node_shader_sepcomb_hsv.cc | 2 + .../nodes/shader/nodes/node_shader_sepcomb_rgb.cc | 2 + .../nodes/shader/nodes/node_shader_tex_brick.cc | 2 +- .../nodes/shader/nodes/node_shader_tex_coord.cc | 8 +- .../shader/nodes/node_shader_tex_environment.cc | 6 +- .../nodes/shader/nodes/node_shader_tex_gradient.cc | 2 +- .../nodes/shader/nodes/node_shader_tex_magic.cc | 2 +- .../nodes/shader/nodes/node_shader_tex_musgrave.cc | 2 +- .../nodes/shader/nodes/node_shader_tex_sky.cc | 52 +- .../nodes/shader/nodes/node_shader_tex_wave.cc | 2 +- .../shader/nodes/node_shader_tex_white_noise.cc | 2 +- .../nodes/shader/nodes/node_shader_value.cc | 7 +- .../nodes/shader/nodes/node_shader_vector_math.cc | 2 +- .../shader/nodes/node_shader_vector_rotate.cc | 2 +- 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100644 source/blender/render/intern/initrender.c create mode 100644 source/blender/render/intern/initrender.cc delete mode 100644 source/blender/render/intern/pipeline.c create mode 100644 source/blender/render/intern/pipeline.cc delete mode 100644 source/blender/render/intern/render_result.c create mode 100644 source/blender/render/intern/render_result.cc delete mode 100644 source/blender/windowmanager/intern/wm_dragdrop.c create mode 100644 source/blender/windowmanager/intern/wm_dragdrop.cc delete mode 100644 source/creator/blender.map delete mode 100644 source/creator/osx_locals.map create mode 100644 source/creator/symbols_apple.map create mode 100644 source/creator/symbols_unix.map (limited to 'source') diff --git a/source/blender/CMakeLists.txt b/source/blender/CMakeLists.txt index 8ba6e7318bb..28c15d9224c 100644 --- a/source/blender/CMakeLists.txt +++ b/source/blender/CMakeLists.txt @@ -151,14 +151,12 @@ add_subdirectory(io) add_subdirectory(functions) add_subdirectory(makesdna) add_subdirectory(makesrna) +add_subdirectory(compositor) if(WITH_BLENDER_THUMBNAILER) add_subdirectory(blendthumb) endif() -if(WITH_COMPOSITOR) - add_subdirectory(compositor) -endif() if(WITH_IMAGE_OPENEXR) add_subdirectory(imbuf/intern/openexr) diff --git a/source/blender/blendthumb/CMakeLists.txt b/source/blender/blendthumb/CMakeLists.txt index 330cefa247a..6160d225d45 100644 --- a/source/blender/blendthumb/CMakeLists.txt +++ b/source/blender/blendthumb/CMakeLists.txt @@ -1,7 +1,7 @@ # SPDX-License-Identifier: GPL-2.0-or-later # Copyright 2006 Blender Foundation. All rights reserved. -#----------------------------------------------------------------------------- +# ----------------------------------------------------------------------------- # Shared Thumbnail Extraction Logic include_directories( diff --git a/source/blender/blendthumb/src/blendthumb_extract.cc b/source/blender/blendthumb/src/blendthumb_extract.cc index de1f50dfdce..fff1242f2ce 100644 --- a/source/blender/blendthumb/src/blendthumb_extract.cc +++ b/source/blender/blendthumb/src/blendthumb_extract.cc @@ -121,6 +121,9 @@ static eThumbStatus blendthumb_extract_from_file_impl(FileReader *file, while (file_read(file, bhead_data, bhead_size)) { /* Parse type and size from `BHead`. */ const int32_t block_size = bytes_to_native_i32(&bhead_data[4], endian_switch); + if (UNLIKELY(block_size < 0)) { + return BT_INVALID_THUMB; + } /* We're looking for the thumbnail, so skip any other block. */ switch (*((int32_t *)bhead_data)) { @@ -133,8 +136,9 @@ static eThumbStatus blendthumb_extract_from_file_impl(FileReader *file, thumb->height = bytes_to_native_i32(&shape[4], endian_switch); /* Verify that image dimensions and data size make sense. */ - size_t data_size = block_size - 8; - const size_t expected_size = thumb->width * thumb->height * 4; + size_t data_size = block_size - sizeof(shape); + const uint64_t expected_size = static_cast(thumb->width) * + static_cast(thumb->height) * 4; if (thumb->width < 0 || thumb->height < 0 || data_size != expected_size) { return BT_INVALID_THUMB; } diff --git a/source/blender/blenfont/BLF_api.h b/source/blender/blenfont/BLF_api.h index 83ca9158efc..d3226a8f609 100644 --- a/source/blender/blenfont/BLF_api.h +++ b/source/blender/blenfont/BLF_api.h @@ -18,10 +18,10 @@ extern "C" { #define BLF_DATAFILES_FONTS_DIR "fonts" /* File name of the default variable-width font. */ -#define BLF_DEFAULT_PROPORTIONAL_FONT "droidsans.ttf" +#define BLF_DEFAULT_PROPORTIONAL_FONT "DejaVuSans.woff2" /* File name of the default fixed-pitch font. */ -#define BLF_DEFAULT_MONOSPACED_FONT "bmonofont-i18n.ttf" +#define BLF_DEFAULT_MONOSPACED_FONT "DejaVuSansMono.woff2" /* enable this only if needed (unused circa 2016) */ #define BLF_BLUR_ENABLE 0 @@ -351,6 +351,10 @@ enum { BLF_DEFAULT = 1 << 14, /** Must only be used as last font in the stack. */ BLF_LAST_RESORT = 1 << 15, + /** Failure to load this font. Don't try again. */ + BLF_BAD_FONT = 1 << 16, + /** This font is managed by the FreeType cache subsystem. */ + BLF_CACHED = 1 << 17, }; #define BLF_DRAW_STR_DUMMY_MAX 1024 diff --git a/source/blender/blenfont/CMakeLists.txt b/source/blender/blenfont/CMakeLists.txt index a2b84290e67..986a261dc4b 100644 --- a/source/blender/blenfont/CMakeLists.txt +++ b/source/blender/blenfont/CMakeLists.txt @@ -10,7 +10,6 @@ set(INC ../imbuf ../makesdna ../makesrna - ../../../intern/glew-mx ../../../intern/guardedalloc ) diff --git a/source/blender/blenfont/intern/blf.c b/source/blender/blenfont/intern/blf.c index a1fcc17ca3f..9d9cc51ebcc 100644 --- a/source/blender/blenfont/intern/blf.c +++ b/source/blender/blenfont/intern/blf.c @@ -22,6 +22,7 @@ #include "MEM_guardedalloc.h" #include "BLI_math.h" +#include "BLI_string.h" #include "BLI_threads.h" #include "BLF_api.h" @@ -98,7 +99,7 @@ bool blf_font_id_is_valid(int fontid) static int blf_search(const char *name) { for (int i = 0; i < BLF_MAX_FONT; i++) { - FontBLF *font = global_font[i]; + const FontBLF *font = global_font[i]; if (font && (STREQ(font->name, name))) { return i; } @@ -122,7 +123,7 @@ bool BLF_has_glyph(int fontid, unsigned int unicode) { FontBLF *font = blf_get(fontid); if (font) { - return FT_Get_Char_Index(font->face, unicode) != FT_Err_Ok; + return blf_get_char_index(font, unicode) != FT_Err_Ok; } return false; } @@ -483,7 +484,7 @@ void BLF_batch_draw_end(void) g_batch.enabled = false; } -static void blf_draw_gl__start(FontBLF *font) +static void blf_draw_gl__start(const FontBLF *font) { /* * The pixmap alignment hack is handle @@ -511,7 +512,7 @@ static void blf_draw_gl__start(FontBLF *font) } } -static void blf_draw_gl__end(FontBLF *font) +static void blf_draw_gl__end(const FontBLF *font) { if ((font->flags & (BLF_ROTATION | BLF_MATRIX | BLF_ASPECT)) != 0) { GPU_matrix_pop(); @@ -885,12 +886,21 @@ void BLF_draw_buffer(int fontid, const char *str, const size_t str_len) char *BLF_display_name_from_file(const char *filepath) { - FontBLF *font = blf_font_new("font_name", filepath); - if (!font) { - return NULL; + /* While listing font directories this function can be called simultaneously from a greater + * number of threads than we want the FreeType cache to keep open at a time. Therefore open + * with own FT_Library object and use FreeType calls directly to avoid any contention. */ + char *name = NULL; + FT_Library ft_library; + if (FT_Init_FreeType(&ft_library) == FT_Err_Ok) { + FT_Face face; + if (FT_New_Face(ft_library, filepath, 0, &face) == FT_Err_Ok) { + if (face->family_name) { + name = BLI_sprintfN("%s %s", face->family_name, face->style_name); + } + FT_Done_Face(face); + } + FT_Done_FreeType(ft_library); } - char *name = blf_display_name(font); - blf_font_free(font); return name; } diff --git a/source/blender/blenfont/intern/blf_font.c b/source/blender/blenfont/intern/blf_font.c index 038e73cc928..eaea88be9ae 100644 --- a/source/blender/blenfont/intern/blf_font.c +++ b/source/blender/blenfont/intern/blf_font.c @@ -17,9 +17,11 @@ #include #include FT_FREETYPE_H +#include FT_CACHE_H /* FreeType Cache. */ #include FT_GLYPH_H -#include FT_TRUETYPE_TABLES_H /* For TT_OS2 */ #include FT_MULTIPLE_MASTERS_H /* Variable font support. */ +#include FT_TRUETYPE_IDS_H /* Code-point coverage constants. */ +#include FT_TRUETYPE_TABLES_H /* For TT_OS2 */ #include "MEM_guardedalloc.h" @@ -28,6 +30,7 @@ #include "BLI_listbase.h" #include "BLI_math.h" #include "BLI_math_color_blend.h" +#include "BLI_path_util.h" #include "BLI_rect.h" #include "BLI_string.h" #include "BLI_string_utf8.h" @@ -52,9 +55,12 @@ BatchBLF g_batch; /* freetype2 handle ONLY for this file! */ -static FT_Library ft_lib; -static SpinLock ft_lib_mutex; -static SpinLock blf_glyph_cache_mutex; +static FT_Library ft_lib = NULL; +static FTC_Manager ftc_manager = NULL; +static FTC_CMapCache ftc_charmap_cache = NULL; + +/* Lock for FreeType library, used around face creation and deletion. */ +static ThreadMutex ft_lib_mutex; /* May be set to #UI_widgetbase_draw_cache_flush. */ static void (*blf_draw_cache_flush)(void) = NULL; @@ -62,20 +68,93 @@ static void (*blf_draw_cache_flush)(void) = NULL; static ft_pix blf_font_height_max_ft_pix(struct FontBLF *font); static ft_pix blf_font_width_max_ft_pix(struct FontBLF *font); +/* -------------------------------------------------------------------- */ + +/** \name FreeType Caching + * \{ */ + +/** + * Called when a face is removed by the cache. FreeType will call #FT_Done_Face. + */ +static void blf_face_finalizer(void *object) +{ + FT_Face face = object; + FontBLF *font = (FontBLF *)face->generic.data; + font->face = NULL; +} + +/** + * Called in response to #FTC_Manager_LookupFace. Now add a face to our font. + * + * \note Unused arguments are kept to match #FTC_Face_Requester function signature. + */ +static FT_Error blf_cache_face_requester(FTC_FaceID faceID, + FT_Library lib, + FT_Pointer UNUSED(reqData), + FT_Face *face) +{ + FontBLF *font = (FontBLF *)faceID; + int err = FT_Err_Cannot_Open_Resource; + + BLI_mutex_lock(&ft_lib_mutex); + if (font->filepath) { + err = FT_New_Face(lib, font->filepath, 0, face); + } + else if (font->mem) { + err = FT_New_Memory_Face(lib, font->mem, (FT_Long)font->mem_size, 0, face); + } + BLI_mutex_unlock(&ft_lib_mutex); + + if (err == FT_Err_Ok) { + font->face = *face; + font->face->generic.data = font; + font->face->generic.finalizer = blf_face_finalizer; + } + else { + /* Clear this on error to avoid exception in FTC_Manager_LookupFace. */ + *face = NULL; + } + + return err; +} + +/** + * Called when the FreeType cache is removing a font size. + */ +static void blf_size_finalizer(void *object) +{ + FT_Size size = object; + FontBLF *font = (FontBLF *)size->generic.data; + font->ft_size = NULL; +} + /* -------------------------------------------------------------------- */ /** \name FreeType Utilities (Internal) * \{ */ -/* Convert a FreeType 26.6 value representing an unscaled design size to factional pixels. */ +uint blf_get_char_index(FontBLF *font, uint charcode) +{ + if (font->flags & BLF_CACHED) { + /* Use char-map cache for much faster lookup. */ + return FTC_CMapCache_Lookup(ftc_charmap_cache, font, -1, charcode); + } + /* Fonts that are not cached need to use the regular lookup function. */ + return blf_ensure_face(font) ? FT_Get_Char_Index(font->face, charcode) : 0; +} + +/* Convert a FreeType 26.6 value representing an unscaled design size to fractional pixels. */ static ft_pix blf_unscaled_F26Dot6_to_pixels(FontBLF *font, FT_Pos value) { + /* Make sure we have a valid font->ft_size. */ + blf_ensure_size(font); + /* Scale value by font size using integer-optimized multiplication. */ - FT_Long scaled = FT_MulFix(value, font->face->size->metrics.x_scale); + FT_Long scaled = FT_MulFix(value, font->ft_size->metrics.x_scale); /* Copied from FreeType's FT_Get_Kerning (with FT_KERNING_DEFAULT), scaling down */ - /* kerning distances at small ppem values so that they don't become too big. */ - if (font->face->size->metrics.x_ppem < 25) { - scaled = FT_MulDiv(scaled, font->face->size->metrics.x_ppem, 25); + /* kerning distances at small PPEM values so that they don't become too big. */ + if (font->ft_size->metrics.x_ppem < 25) { + scaled = FT_MulDiv(scaled, font->ft_size->metrics.x_ppem, 25); } return (ft_pix)scaled; @@ -144,7 +223,7 @@ void blf_batch_draw_begin(FontBLF *font) g_batch.ofs[1] = font->pos[1]; } else { - /* Offset is baked in modelview mat. */ + /* Offset is baked in model-view matrix. */ zero_v2_int(g_batch.ofs); } @@ -152,16 +231,16 @@ void blf_batch_draw_begin(FontBLF *font) float gpumat[4][4]; GPU_matrix_model_view_get(gpumat); - bool mat_changed = (memcmp(gpumat, g_batch.mat, sizeof(g_batch.mat)) != 0); + bool mat_changed = equals_m4m4(gpumat, g_batch.mat) == false; if (mat_changed) { - /* Modelviewmat is no longer the same. - * Flush cache but with the previous mat. */ + /* Model view matrix is no longer the same. + * Flush cache but with the previous matrix. */ GPU_matrix_push(); GPU_matrix_set(g_batch.mat); } - /* flush cache if config is not the same. */ + /* Flush cache if configuration is not the same. */ if (mat_changed || font_changed || shader_changed) { blf_batch_draw(); g_batch.simple_shader = simple_shader; @@ -174,7 +253,7 @@ void blf_batch_draw_begin(FontBLF *font) if (mat_changed) { GPU_matrix_pop(); - /* Save for next memcmp. */ + /* Save for next `memcmp`. */ memcpy(g_batch.mat, gpumat, sizeof(g_batch.mat)); } } @@ -200,7 +279,7 @@ static GPUTexture *blf_batch_cache_texture_load(void) int offset_x = bitmap_len_landed % tex_width; int offset_y = bitmap_len_landed / tex_width; - /* TODO(germano): Update more than one row in a single call. */ + /* TODO(@germano): Update more than one row in a single call. */ while (remain) { int remain_row = tex_width - offset_x; int width = remain > remain_row ? remain_row : remain; @@ -294,22 +373,22 @@ BLI_INLINE ft_pix blf_kerning(FontBLF *font, const GlyphBLF *g_prev, const Glyph /* Small adjust if there is hinting. */ adjustment += g->lsb_delta - ((g_prev) ? g_prev->rsb_delta : 0); - if (FT_HAS_KERNING(font->face) && g_prev) { + if (FT_HAS_KERNING(font) && g_prev) { FT_Vector delta = {KERNING_ENTRY_UNSET}; /* Get unscaled kerning value from our cache if ASCII. */ - if ((g_prev->c < KERNING_CACHE_TABLE_SIZE) && (g->c < GLYPH_ASCII_TABLE_SIZE)) { + if ((g_prev->c < KERNING_CACHE_TABLE_SIZE) && (g->c < KERNING_CACHE_TABLE_SIZE)) { delta.x = font->kerning_cache->ascii_table[g->c][g_prev->c]; } /* If not ASCII or not found in cache, ask FreeType for kerning. */ - if (UNLIKELY(delta.x == KERNING_ENTRY_UNSET)) { + if (UNLIKELY(font->face && delta.x == KERNING_ENTRY_UNSET)) { /* Note that this function sets delta values to zero on any error. */ FT_Get_Kerning(font->face, g_prev->idx, g->idx, FT_KERNING_UNSCALED, &delta); } /* If ASCII we save this value to our cache for quicker access next time. */ - if ((g_prev->c < KERNING_CACHE_TABLE_SIZE) && (g->c < GLYPH_ASCII_TABLE_SIZE)) { + if ((g_prev->c < KERNING_CACHE_TABLE_SIZE) && (g->c < KERNING_CACHE_TABLE_SIZE)) { font->kerning_cache->ascii_table[g->c][g_prev->c] = (int)delta.x; } @@ -333,7 +412,7 @@ static void blf_font_draw_ex(FontBLF *font, const char *str, const size_t str_len, struct ResultBLF *r_info, - ft_pix pen_y) + const ft_pix pen_y) { GlyphBLF *g, *g_prev = NULL; ft_pix pen_x = 0; @@ -434,7 +513,7 @@ static void blf_font_draw_buffer_ex(FontBLF *font, /* buffer specific vars */ FontBufInfoBLF *buf_info = &font->buf_info; const float *b_col_float = buf_info->col_float; - const unsigned char *b_col_char = buf_info->col_char; + const uchar *b_col_char = buf_info->col_char; int chx, chy; int y, x; @@ -523,7 +602,7 @@ static void blf_font_draw_buffer_ex(FontBLF *font, const size_t buf_ofs = (((size_t)(chx + x) + ((size_t)(pen_y_px + y) * (size_t)buf_info->dims[0])) * (size_t)buf_info->ch); - unsigned char *cbuf = buf_info->cbuf + buf_ofs; + uchar *cbuf = buf_info->cbuf + buf_ofs; uchar font_pixel[4]; font_pixel[0] = b_col_char[0]; @@ -836,7 +915,7 @@ static void blf_font_boundbox_foreach_glyph_ex(FontBLF *font, size_t i = 0, i_curr; rcti gbox_px; - if (str_len == 0) { + if (str_len == 0 || str[0] == 0) { /* early output. */ return; } @@ -923,8 +1002,7 @@ static void blf_font_wrap_apply(FontBLF *font, int lines = 0; ft_pix pen_x_next = 0; - /* Space between lines needs to be aligned to the pixel grid (T97310). */ - ft_pix line_height = FT_PIX_FLOOR(blf_font_height_max_ft_pix(font)); + ft_pix line_height = blf_font_height_max_ft_pix(font); GlyphCacheBLF *gc = blf_glyph_cache_acquire(font); @@ -1081,14 +1159,14 @@ int blf_font_count_missing_chars(FontBLF *font, *r_tot_chars = 0; while (i < str_len) { - unsigned int c; + uint c; if ((c = str[i]) < GLYPH_ASCII_TABLE_SIZE) { i++; } else { c = BLI_str_utf8_as_unicode_step(str, str_len, &i); - if (FT_Get_Char_Index((font)->face, c) == 0) { + if (blf_get_char_index(font, c) == 0) { missing++; } } @@ -1105,18 +1183,9 @@ int blf_font_count_missing_chars(FontBLF *font, static ft_pix blf_font_height_max_ft_pix(FontBLF *font) { - ft_pix height_max; - FT_Face face = font->face; - if (FT_IS_SCALABLE(face)) { - height_max = ft_pix_from_int((int)(face->ascender - face->descender) * - (int)face->size->metrics.y_ppem) / - (ft_pix)face->units_per_EM; - } - else { - height_max = (ft_pix)face->size->metrics.height; - } - /* can happen with size 1 fonts */ - return MAX2(height_max, ft_pix_from_int(1)); + blf_ensure_size(font); + /* Metrics.height is rounded to pixel. Force minimum of one pixel. */ + return MAX2((ft_pix)font->ft_size->metrics.height, ft_pix_from_int(1)); } int blf_font_height_max(FontBLF *font) @@ -1126,18 +1195,9 @@ int blf_font_height_max(FontBLF *font) static ft_pix blf_font_width_max_ft_pix(FontBLF *font) { - ft_pix width_max; - const FT_Face face = font->face; - if (FT_IS_SCALABLE(face)) { - width_max = ft_pix_from_int((int)(face->bbox.xMax - face->bbox.xMin) * - (int)face->size->metrics.x_ppem) / - (ft_pix)face->units_per_EM; - } - else { - width_max = (ft_pix)face->size->metrics.max_advance; - } - /* can happen with size 1 fonts */ - return MAX2(width_max, ft_pix_from_int(1)); + blf_ensure_size(font); + /* Metrics.max_advance is rounded to pixel. Force minimum of one pixel. */ + return MAX2((ft_pix)font->ft_size->metrics.max_advance, ft_pix_from_int(1)); } int blf_font_width_max(FontBLF *font) @@ -1147,17 +1207,19 @@ int blf_font_width_max(FontBLF *font) int blf_font_descender(FontBLF *font) { - return ft_pix_to_int((ft_pix)font->face->size->metrics.descender); + blf_ensure_size(font); + return ft_pix_to_int((ft_pix)font->ft_size->metrics.descender); } int blf_font_ascender(FontBLF *font) { - return ft_pix_to_int((ft_pix)font->face->size->metrics.ascender); + blf_ensure_size(font); + return ft_pix_to_int((ft_pix)font->ft_size->metrics.ascender); } char *blf_display_name(FontBLF *font) { - if (!font->face->family_name) { + if (!blf_ensure_face(font) || !font->face->family_name) { return NULL; } return BLI_sprintfN("%s %s", font->face->family_name, font->face->style_name); @@ -1172,16 +1234,34 @@ char *blf_display_name(FontBLF *font) int blf_font_init(void) { memset(&g_batch, 0, sizeof(g_batch)); - BLI_spin_init(&ft_lib_mutex); - BLI_spin_init(&blf_glyph_cache_mutex); - return FT_Init_FreeType(&ft_lib); + BLI_mutex_init(&ft_lib_mutex); + int err = FT_Init_FreeType(&ft_lib); + if (err == FT_Err_Ok) { + /* Create a FreeType cache manager. */ + err = FTC_Manager_New(ft_lib, + BLF_CACHE_MAX_FACES, + BLF_CACHE_MAX_SIZES, + BLF_CACHE_BYTES, + blf_cache_face_requester, + NULL, + &ftc_manager); + if (err == FT_Err_Ok) { + /* Create a charmap cache to speed up glyph index lookups. */ + err = FTC_CMapCache_New(ftc_manager, &ftc_charmap_cache); + } + } + return err; } void blf_font_exit(void) { - FT_Done_FreeType(ft_lib); - BLI_spin_end(&ft_lib_mutex); - BLI_spin_end(&blf_glyph_cache_mutex); + BLI_mutex_end(&ft_lib_mutex); + if (ftc_manager) { + FTC_Manager_Done(ftc_manager); + } + if (ft_lib) { + FT_Done_FreeType(ft_lib); + } blf_batch_draw_exit(); } @@ -1238,20 +1318,38 @@ static void blf_font_fill(FontBLF *font) font->buf_info.col_init[1] = 0; font->buf_info.col_init[2] = 0; font->buf_info.col_init[3] = 0; - - font->ft_lib = ft_lib; - font->ft_lib_mutex = &ft_lib_mutex; - font->glyph_cache_mutex = &blf_glyph_cache_mutex; } -FontBLF *blf_font_new(const char *name, const char *filepath) +/** + * Create an FT_Face for this font if not already existing. + */ +bool blf_ensure_face(FontBLF *font) { - FontBLF *font; + if (font->face) { + return true; + } + + if (font->flags & BLF_BAD_FONT) { + return false; + } + FT_Error err; - char *mfile; - font = (FontBLF *)MEM_callocN(sizeof(FontBLF), "blf_font_new"); - err = FT_New_Face(ft_lib, filepath, 0, &font->face); + if (font->flags & BLF_CACHED) { + err = FTC_Manager_LookupFace(ftc_manager, font, &font->face); + } + else { + BLI_mutex_lock(&ft_lib_mutex); + if (font->filepath) { + err = FT_New_Face(font->ft_lib, font->filepath, 0, &font->face); + } + if (font->mem) { + err = FT_New_Memory_Face(font->ft_lib, font->mem, (FT_Long)font->mem_size, 0, &font->face); + } + font->face->generic.data = font; + BLI_mutex_unlock(&ft_lib_mutex); + } + if (err) { if (ELEM(err, FT_Err_Unknown_File_Format, FT_Err_Unimplemented_Feature)) { printf("Format of this font file is not supported\n"); @@ -1259,8 +1357,13 @@ FontBLF *blf_font_new(const char *name, const char *filepath) else { printf("Error encountered while opening font file\n"); } - MEM_freeN(font); - return NULL; + font->flags |= BLF_BAD_FONT; + return false; + } + + if (font->face && !(font->face->face_flags & FT_FACE_FLAG_SCALABLE)) { + printf("Font is not scalable\n"); + return false; } err = FT_Select_Charmap(font->face, FT_ENCODING_UNICODE); @@ -1272,48 +1375,49 @@ FontBLF *blf_font_new(const char *name, const char *filepath) } if (err) { printf("Can't set a character map!\n"); - FT_Done_Face(font->face); - MEM_freeN(font); - return NULL; + font->flags |= BLF_BAD_FONT; + return false; } - mfile = blf_dir_metrics_search(filepath); - if (mfile) { - err = FT_Attach_File(font->face, mfile); - if (err) { - fprintf(stderr, "FT_Attach_File failed to load '%s' with error %d\n", filepath, (int)err); + if (font->filepath) { + char *mfile = blf_dir_metrics_search(font->filepath); + if (mfile) { + err = FT_Attach_File(font->face, mfile); + if (err) { + fprintf(stderr, + "FT_Attach_File failed to load '%s' with error %d\n", + font->filepath, + (int)err); + } + MEM_freeN(mfile); } - MEM_freeN(mfile); } - if (FT_HAS_MULTIPLE_MASTERS(font->face)) { - FT_Get_MM_Var(font->face, &(font->variations)); + if (!(font->flags & BLF_CACHED)) { + /* Not cached so point at the face's size for convenience. */ + font->ft_size = font->face->size; } - font->name = BLI_strdup(name); - font->filepath = BLI_strdup(filepath); - blf_font_fill(font); + font->face_flags = font->face->face_flags; + + if (FT_HAS_MULTIPLE_MASTERS(font)) { + FT_Get_MM_Var(font->face, &(font->variations)); + } /* Save TrueType table with bits to quickly test most unicode block coverage. */ TT_OS2 *os2_table = (TT_OS2 *)FT_Get_Sfnt_Table(font->face, FT_SFNT_OS2); if (os2_table) { - font->UnicodeRanges[0] = (uint)os2_table->ulUnicodeRange1; - font->UnicodeRanges[1] = (uint)os2_table->ulUnicodeRange2; - font->UnicodeRanges[2] = (uint)os2_table->ulUnicodeRange3; - font->UnicodeRanges[3] = (uint)os2_table->ulUnicodeRange4; - } - - /* Detect "Last resort" fonts. They have everything. Usually except last 5 bits. */ - if (font->UnicodeRanges[0] == 0xffffffffU && font->UnicodeRanges[1] == 0xffffffffU && - font->UnicodeRanges[2] == 0xffffffffU && font->UnicodeRanges[3] >= 0x7FFFFFFU) { - font->flags |= BLF_LAST_RESORT; + font->unicode_ranges[0] = (uint)os2_table->ulUnicodeRange1; + font->unicode_ranges[1] = (uint)os2_table->ulUnicodeRange2; + font->unicode_ranges[2] = (uint)os2_table->ulUnicodeRange3; + font->unicode_ranges[3] = (uint)os2_table->ulUnicodeRange4; } - if (FT_IS_FIXED_WIDTH(font->face)) { + if (FT_IS_FIXED_WIDTH(font)) { font->flags |= BLF_MONOSPACED; } - if (FT_HAS_KERNING(font->face)) { + if (FT_HAS_KERNING(font) && !font->kerning_cache) { /* Create kerning cache table and fill with value indicating "unset". */ font->kerning_cache = MEM_mallocN(sizeof(KerningCacheBLF), __func__); for (uint i = 0; i < KERNING_CACHE_TABLE_SIZE; i++) { @@ -1323,49 +1427,138 @@ FontBLF *blf_font_new(const char *name, const char *filepath) } } - return font; + return true; } -void blf_font_attach_from_mem(FontBLF *font, const unsigned char *mem, int mem_size) +struct FaceDetails { + char name[50]; + uint coverage1; + uint coverage2; + uint coverage3; + uint coverage4; +}; + +/* Details about the fallback fonts we ship, so that we can load only when needed. */ +static const struct FaceDetails static_face_details[] = { + {"lastresort.woff2", UINT32_MAX, UINT32_MAX, UINT32_MAX, UINT32_MAX}, + {"Noto Sans CJK Regular.woff2", 0x30000083L, 0x2BDF3C10L, 0x16L, 0}, + {"NotoEmoji-VariableFont_wght.woff2", 0x80000003L, 0x241E4ACL, 0x14000000L, 0x4000000L}, + {"NotoSansArabic-VariableFont_wdth,wght.woff2", + TT_UCR_ARABIC, + (uint)TT_UCR_ARABIC_PRESENTATION_FORMS_A, + TT_UCR_ARABIC_PRESENTATION_FORMS_B, + 0}, + {"NotoSansArmenian-VariableFont_wdth,wght.woff2", TT_UCR_ARMENIAN, 0, 0, 0}, + {"NotoSansBengali-VariableFont_wdth,wght.woff2", TT_UCR_BENGALI, 0, 0, 0}, + {"NotoSansDevanagari-Regular.woff2", TT_UCR_DEVANAGARI, 0, 0, 0}, + {"NotoSansEthiopic-Regular.woff2", 0, 0, TT_UCR_ETHIOPIC, 0}, + {"NotoSansGeorgian-VariableFont_wdth,wght.woff2", TT_UCR_GEORGIAN, 0, 0, 0}, + {"NotoSansGujarati-Regular.woff2", TT_UCR_GUJARATI, 0, 0, 0}, + {"NotoSansGurmukhi-VariableFont_wdth,wght.woff2", TT_UCR_GURMUKHI, 0, 0, 0}, + {"NotoSansHebrew-Regular.woff2", TT_UCR_HEBREW, 0, 0, 0}, + {"NotoSansJavanese-Regular.woff2", 0x80000003L, 0x2000L, 0, 0}, + {"NotoSansKannada-VariableFont_wdth,wght.woff2", TT_UCR_KANNADA, 0, 0, 0}, + {"NotoSansMalayalam-VariableFont_wdth,wght.woff2", TT_UCR_MALAYALAM, 0, 0, 0}, + {"NotoSansMath-Regular.woff2", 0, TT_UCR_MATHEMATICAL_OPERATORS, 0, 0}, + {"NotoSansMyanmar-Regular.woff2", 0, 0, TT_UCR_MYANMAR, 0}, + {"NotoSansSymbols-VariableFont_wght.woff2", 0x3L, 0x200E4B4L, 0, 0}, + {"NotoSansSymbols2-Regular.woff2", 0x80000003L, 0x200E3E4L, 0x40020L, 0x580A048L}, + {"NotoSansTamil-VariableFont_wdth,wght.woff2", TT_UCR_TAMIL, 0, 0, 0}, + {"NotoSansTelugu-VariableFont_wdth,wght.woff2", TT_UCR_TELUGU, 0, 0, 0}, + {"NotoSansThai-VariableFont_wdth,wght.woff2", TT_UCR_THAI, 0, 0, 0}, +}; + +/** + * Create a new font from filename OR memory pointer. + * For normal operation pass NULL as FT_Library object. Pass a custom FT_Library if you + * want to use the font without its lifetime being managed by the FreeType cache subsystem. + */ +FontBLF *blf_font_new_ex(const char *name, + const char *filepath, + const uchar *mem, + const size_t mem_size, + void *ft_library) { - FT_Open_Args open; + FontBLF *font = (FontBLF *)MEM_callocN(sizeof(FontBLF), "blf_font_new"); - open.flags = FT_OPEN_MEMORY; - open.memory_base = (const FT_Byte *)mem; - open.memory_size = mem_size; - FT_Attach_Stream(font->face, &open); -} + font->name = BLI_strdup(name); + font->filepath = filepath ? BLI_strdup(filepath) : NULL; + if (mem) { + font->mem = (void *)mem; + font->mem_size = mem_size; + } + blf_font_fill(font); -FontBLF *blf_font_new_from_mem(const char *name, const unsigned char *mem, int mem_size) -{ - FontBLF *font; - FT_Error err; + if (ft_library && ((FT_Library)ft_library != ft_lib)) { + font->ft_lib = (FT_Library)ft_library; + } + else { + font->ft_lib = ft_lib; + font->flags |= BLF_CACHED; + } - font = (FontBLF *)MEM_callocN(sizeof(FontBLF), "blf_font_new_from_mem"); - err = FT_New_Memory_Face(ft_lib, mem, mem_size, 0, &font->face); - if (err) { - MEM_freeN(font); - return NULL; + font->ft_lib = ft_library ? (FT_Library)ft_library : ft_lib; + + BLI_mutex_init(&font->glyph_cache_mutex); + + /* If we have static details about this font file, we don't have to load the Face yet. */ + bool face_needed = true; + + if (font->filepath) { + const struct FaceDetails *static_details = NULL; + char filename[256]; + for (int i = 0; i < (int)ARRAY_SIZE(static_face_details); i++) { + BLI_split_file_part(font->filepath, filename, sizeof(filename)); + if (STREQ(static_face_details[i].name, filename)) { + static_details = &static_face_details[i]; + font->unicode_ranges[0] = static_details->coverage1; + font->unicode_ranges[1] = static_details->coverage2; + font->unicode_ranges[2] = static_details->coverage3; + font->unicode_ranges[3] = static_details->coverage4; + face_needed = false; + break; + } + } } - err = FT_Select_Charmap(font->face, ft_encoding_unicode); - if (err) { - printf("Can't set the unicode character map!\n"); - FT_Done_Face(font->face); - MEM_freeN(font); - return NULL; + if (face_needed) { + if (!blf_ensure_face(font)) { + blf_font_free(font); + return NULL; + } } - if (FT_HAS_MULTIPLE_MASTERS(font->face)) { - FT_Get_MM_Var(font->face, &(font->variations)); + /* Detect "Last resort" fonts. They have everything. Usually except last 5 bits. */ + if (font->unicode_ranges[0] == 0xffffffffU && font->unicode_ranges[1] == 0xffffffffU && + font->unicode_ranges[2] == 0xffffffffU && font->unicode_ranges[3] >= 0x7FFFFFFU) { + font->flags |= BLF_LAST_RESORT; } - font->name = BLI_strdup(name); - font->filepath = NULL; - blf_font_fill(font); return font; } +FontBLF *blf_font_new(const char *name, const char *filepath) +{ + return blf_font_new_ex(name, filepath, NULL, 0, NULL); +} + +FontBLF *blf_font_new_from_mem(const char *name, const uchar *mem, const size_t mem_size) +{ + return blf_font_new_ex(name, NULL, mem, mem_size, NULL); +} + +void blf_font_attach_from_mem(FontBLF *font, const uchar *mem, const size_t mem_size) +{ + FT_Open_Args open; + + open.flags = FT_OPEN_MEMORY; + open.memory_base = (const FT_Byte *)mem; + open.memory_size = (FT_Long)mem_size; + if (blf_ensure_face(font)) { + FT_Attach_Stream(font->face, &open); + } +} + void blf_font_free(FontBLF *font) { blf_glyph_cache_clear(font); @@ -1375,16 +1568,29 @@ void blf_font_free(FontBLF *font) } if (font->variations) { - FT_Done_MM_Var(ft_lib, font->variations); + FT_Done_MM_Var(font->ft_lib, font->variations); } - FT_Done_Face(font->face); + if (font->face) { + BLI_mutex_lock(&ft_lib_mutex); + if (font->flags & BLF_CACHED) { + FTC_Manager_RemoveFaceID(ftc_manager, font); + } + else { + FT_Done_Face(font->face); + } + BLI_mutex_unlock(&ft_lib_mutex); + font->face = NULL; + } if (font->filepath) { MEM_freeN(font->filepath); } if (font->name) { MEM_freeN(font->name); } + + BLI_mutex_end(&font->glyph_cache_mutex); + MEM_freeN(font); } @@ -1394,24 +1600,64 @@ void blf_font_free(FontBLF *font) /** \name Font Configure * \{ */ -bool blf_font_size(FontBLF *font, float size, unsigned int dpi) +void blf_ensure_size(FontBLF *font) +{ + if (font->ft_size || !(font->flags & BLF_CACHED)) { + return; + } + + FTC_ScalerRec scaler = {0}; + scaler.face_id = font; + scaler.width = 0; + scaler.height = round_fl_to_uint(font->size * 64.0f); + scaler.pixel = 0; + scaler.x_res = font->dpi; + scaler.y_res = font->dpi; + if (FTC_Manager_LookupSize(ftc_manager, &scaler, &font->ft_size) == FT_Err_Ok) { + font->ft_size->generic.data = (void *)font; + font->ft_size->generic.finalizer = blf_size_finalizer; + return; + } + + BLI_assert_unreachable(); +} + +bool blf_font_size(FontBLF *font, float size, uint dpi) { + if (!blf_ensure_face(font)) { + return false; + } + /* FreeType uses fixed-point integers in 64ths. */ - FT_F26Dot6 ft_size = lroundf(size * 64.0f); + FT_UInt ft_size = round_fl_to_uint(size * 64.0f); /* Adjust our new size to be on even 64ths. */ size = (float)ft_size / 64.0f; if (font->size != size || font->dpi != dpi) { - if (FT_Set_Char_Size(font->face, 0, ft_size, dpi, dpi) == FT_Err_Ok) { - font->size = size; - font->dpi = dpi; + if (font->flags & BLF_CACHED) { + FTC_ScalerRec scaler = {0}; + scaler.face_id = font; + scaler.width = 0; + scaler.height = ft_size; + scaler.pixel = 0; + scaler.x_res = dpi; + scaler.y_res = dpi; + if (FTC_Manager_LookupSize(ftc_manager, &scaler, &font->ft_size) != FT_Err_Ok) { + return false; + } + font->ft_size->generic.data = (void *)font; + font->ft_size->generic.finalizer = blf_size_finalizer; } else { - printf("The current font does not support the size, %f and DPI, %u\n", size, dpi); - return false; + if (FT_Set_Char_Size(font->face, 0, ft_size, dpi, dpi) != FT_Err_Ok) { + return false; + } + font->ft_size = font->face->size; } } + font->size = size; + font->dpi = dpi; return true; } diff --git a/source/blender/blenfont/intern/blf_font_default.c b/source/blender/blenfont/intern/blf_font_default.c index 1bde25b5776..d35692f6eae 100644 --- a/source/blender/blenfont/intern/blf_font_default.c +++ b/source/blender/blenfont/intern/blf_font_default.c @@ -16,6 +16,10 @@ #include "BKE_appdir.h" +#ifdef WIN32 +# include "BLI_winstuff.h" +#endif + static int blf_load_font_default(const char *filename, const bool unique) { const char *dir = BKE_appdir_folder_id(BLENDER_DATAFILES, BLF_DATAFILES_FONTS_DIR); @@ -47,34 +51,51 @@ int BLF_load_mono_default(const bool unique) return font_id; } +static void blf_load_datafiles_dir(void) +{ + const char *datafiles_fonts_dir = BLF_DATAFILES_FONTS_DIR SEP_STR; + const char *path = BKE_appdir_folder_id(BLENDER_DATAFILES, datafiles_fonts_dir); + if (UNLIKELY(!path)) { + fprintf(stderr, "Font data directory \"%s\" could not be detected!\n", datafiles_fonts_dir); + return; + } + if (UNLIKELY(!BLI_exists(path))) { + fprintf(stderr, "Font data directory \"%s\" does not exist!\n", path); + return; + } + + struct direntry *file_list; + uint file_list_num = BLI_filelist_dir_contents(path, &file_list); + for (int i = 0; i < file_list_num; i++) { + if (S_ISDIR(file_list[i].s.st_mode)) { + continue; + } + + const char *filepath = file_list[i].path; + if (!BLI_path_extension_check_n( + filepath, ".ttf", ".ttc", ".otf", ".otc", ".woff", ".woff2", NULL)) { + continue; + } + if (BLF_is_loaded(filepath)) { + continue; + } + + /* Attempt to load the font. */ + int font_id = BLF_load(filepath); + if (font_id == -1) { + fprintf(stderr, "Unable to load font: %s\n", filepath); + continue; + } + + BLF_enable(font_id, BLF_DEFAULT); + } + BLI_filelist_free(file_list, file_list_num); +} + void BLF_load_font_stack() { /* Load these if not already, might have been replaced by user custom. */ BLF_load_default(false); BLF_load_mono_default(false); - - const char *path = BKE_appdir_folder_id(BLENDER_DATAFILES, BLF_DATAFILES_FONTS_DIR SEP_STR); - if (path && BLI_exists(path)) { - struct direntry *dir; - uint num_files = BLI_filelist_dir_contents(path, &dir); - for (int f = 0; f < num_files; f++) { - if (!FILENAME_IS_CURRPAR(dir[f].relname) && !BLI_is_dir(dir[f].path)) { - if (!BLF_is_loaded(dir[f].path)) { - int font_id = BLF_load(dir[f].path); - if (font_id == -1) { - fprintf(stderr, "Unable to load font: %s\n", dir[f].path); - } - else { - BLF_enable(font_id, BLF_DEFAULT); - /* TODO: FontBLF will later load FT_Face on demand. When this is in - * place we can drop this face now since we have all needed data. */ - } - } - } - } - BLI_filelist_free(dir, num_files); - } - else { - fprintf(stderr, "Fonts not found at %s\n", path); - } + blf_load_datafiles_dir(); } diff --git a/source/blender/blenfont/intern/blf_glyph.c b/source/blender/blenfont/intern/blf_glyph.c index 215f79e6795..c08d52307b7 100644 --- a/source/blender/blenfont/intern/blf_glyph.c +++ b/source/blender/blenfont/intern/blf_glyph.c @@ -23,9 +23,6 @@ #include "MEM_guardedalloc.h" -#include "DNA_userdef_types.h" -#include "DNA_vec_types.h" - #include "BLI_listbase.h" #include "BLI_rect.h" #include "BLI_threads.h" @@ -33,7 +30,6 @@ #include "BLF_api.h" #include "GPU_capabilities.h" -#include "GPU_immediate.h" #include "blf_internal.h" #include "blf_internal_types.h" @@ -42,6 +38,13 @@ #include "BLI_strict_flags.h" #include "BLI_string_utf8.h" +/** + * Convert glyph coverage amounts to lightness values. Uses a LUT that perceptually improves + * anti-aliasing and results in text that looks a bit fuller and slightly brighter. This should + * be reconsidered in some - or all - cases when we transform the entire UI. + */ +#define BLF_GAMMA_CORRECT_GLYPHS + /* -------------------------------------------------------------------- */ /** \name Internal Utilities * \{ */ @@ -60,7 +63,7 @@ static FT_Fixed to_16dot16(double val) /** \name Glyph Cache * \{ */ -static GlyphCacheBLF *blf_glyph_cache_find(FontBLF *font, float size, unsigned int dpi) +static GlyphCacheBLF *blf_glyph_cache_find(const FontBLF *font, const float size, uint dpi) { GlyphCacheBLF *gc = (GlyphCacheBLF *)font->cache.first; while (gc) { @@ -93,17 +96,19 @@ static GlyphCacheBLF *blf_glyph_cache_new(FontBLF *font) memset(gc->glyph_ascii_table, 0, sizeof(gc->glyph_ascii_table)); memset(gc->bucket, 0, sizeof(gc->bucket)); + blf_ensure_size(font); + /* Determine ideal fixed-width size for monospaced output. */ - FT_UInt gindex = FT_Get_Char_Index(font->face, U'0'); - if (gindex) { + FT_UInt gindex = blf_get_char_index(font, U'0'); + if (gindex && font->face) { FT_Fixed advance = 0; FT_Get_Advance(font->face, gindex, FT_LOAD_NO_HINTING, &advance); /* Use CSS 'ch unit' width, advance of zero character. */ gc->fixed_width = (int)(advance >> 16); } else { - /* Font does not contain "0" so use CSS fallback of 1/2 of em. */ - gc->fixed_width = (int)((font->face->size->metrics.height / 2) >> 6); + /* Font does not have a face or does not contain "0" so use CSS fallback of 1/2 of em. */ + gc->fixed_width = (int)((font->ft_size->metrics.height / 2) >> 6); } if (gc->fixed_width < 1) { gc->fixed_width = 1; @@ -115,7 +120,7 @@ static GlyphCacheBLF *blf_glyph_cache_new(FontBLF *font) GlyphCacheBLF *blf_glyph_cache_acquire(FontBLF *font) { - BLI_spin_lock(font->glyph_cache_mutex); + BLI_mutex_lock(&font->glyph_cache_mutex); GlyphCacheBLF *gc = blf_glyph_cache_find(font, font->size, font->dpi); @@ -128,7 +133,7 @@ GlyphCacheBLF *blf_glyph_cache_acquire(FontBLF *font) void blf_glyph_cache_release(FontBLF *font) { - BLI_spin_unlock(font->glyph_cache_mutex); + BLI_mutex_unlock(&font->glyph_cache_mutex); } static void blf_glyph_cache_free(GlyphCacheBLF *gc) @@ -152,13 +157,13 @@ void blf_glyph_cache_clear(FontBLF *font) { GlyphCacheBLF *gc; - BLI_spin_lock(font->glyph_cache_mutex); + BLI_mutex_lock(&font->glyph_cache_mutex); while ((gc = BLI_pophead(&font->cache))) { blf_glyph_cache_free(gc); } - BLI_spin_unlock(font->glyph_cache_mutex); + BLI_mutex_unlock(&font->glyph_cache_mutex); } /** @@ -166,7 +171,7 @@ void blf_glyph_cache_clear(FontBLF *font) * * \return NULL if not found. */ -static GlyphBLF *blf_glyph_cache_find_glyph(GlyphCacheBLF *gc, uint charcode) +static GlyphBLF *blf_glyph_cache_find_glyph(const GlyphCacheBLF *gc, uint charcode) { if (charcode < GLYPH_ASCII_TABLE_SIZE) { return gc->glyph_ascii_table[charcode]; @@ -182,6 +187,43 @@ static GlyphBLF *blf_glyph_cache_find_glyph(GlyphCacheBLF *gc, uint charcode) return NULL; } +#ifdef BLF_GAMMA_CORRECT_GLYPHS + +/** + * Gamma correction of glyph coverage values with widely-recommended gamma of 1.43. + * "The reasons are historical. Because so many programmers have neglected gamma blending for so + * long, people who have created fonts have tried to work around the problem of fonts looking too + * thin by just making the fonts thicker! Obviously it doesn't help the jaggedness, but it does + * make them look the proper weight, as originally intended. The obvious problem with this is + * that if we want to gamma blend correctly many older fonts will look wrong. So we compromise, + * and use a lower gamma value, so we get a bit better anti-aliasing, but the fonts don't look too + * heavy." + * https://www.puredevsoftware.com/blog/2019/01/22/sub-pixel-gamma-correct-font-rendering/ + */ +static uchar blf_glyph_gamma(uchar c) +{ + /* The following is `(char)(powf(c / 256.0f, 1.0f / 1.43f) * 256.0f)`. */ + static const uchar gamma[256] = { + 0, 5, 9, 11, 14, 16, 19, 21, 23, 25, 26, 28, 30, 32, 34, 35, 37, 38, + 40, 41, 43, 44, 46, 47, 49, 50, 52, 53, 54, 56, 57, 58, 60, 61, 62, 64, + 65, 66, 67, 69, 70, 71, 72, 73, 75, 76, 77, 78, 79, 80, 82, 83, 84, 85, + 86, 87, 88, 89, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, + 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, + 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 133, 134, 135, 136, 137, 138, 139, + 140, 141, 142, 143, 143, 144, 145, 146, 147, 148, 149, 150, 151, 151, 152, 153, 154, 155, + 156, 157, 157, 158, 159, 160, 161, 162, 163, 163, 164, 165, 166, 167, 168, 168, 169, 170, + 171, 172, 173, 173, 174, 175, 176, 177, 178, 178, 179, 180, 181, 182, 182, 183, 184, 185, + 186, 186, 187, 188, 189, 190, 190, 191, 192, 193, 194, 194, 195, 196, 197, 198, 198, 199, + 200, 201, 201, 202, 203, 204, 205, 205, 206, 207, 208, 208, 209, 210, 211, 211, 212, 213, + 214, 214, 215, 216, 217, 217, 218, 219, 220, 220, 221, 222, 223, 223, 224, 225, 226, 226, + 227, 228, 229, 229, 230, 231, 231, 232, 233, 234, 234, 235, 236, 237, 237, 238, 239, 239, + 240, 241, 242, 242, 243, 244, 244, 245, 246, 247, 247, 248, 249, 249, 250, 251, 251, 252, + 253, 254, 254, 255}; + return gamma[c]; +} + +#endif /* BLF_GAMMA_CORRECT_GLYPHS */ + /** * Add a rendered glyph to a cache. */ @@ -217,11 +259,19 @@ static GlyphBLF *blf_glyph_cache_add_glyph( glyph->bitmap.buffer[i] = glyph->bitmap.buffer[i] ? 255 : 0; } } + else { +#ifdef BLF_GAMMA_CORRECT_GLYPHS + /* Convert coverage amounts to perceptually-improved lightness values. */ + for (int i = 0; i < buffer_size; i++) { + glyph->bitmap.buffer[i] = blf_glyph_gamma(glyph->bitmap.buffer[i]); + } +#endif /* BLF_GAMMA_CORRECT_GLYPHS */ + } g->bitmap = MEM_mallocN((size_t)buffer_size, "glyph bitmap"); memcpy(g->bitmap, glyph->bitmap.buffer, (size_t)buffer_size); } - unsigned int key = blf_hash(g->c); + const uint key = blf_hash(g->c); BLI_addhead(&(gc->bucket[key]), g); if (charcode < GLYPH_ASCII_TABLE_SIZE) { gc->glyph_ascii_table[charcode] = g; @@ -230,18 +280,24 @@ static GlyphBLF *blf_glyph_cache_add_glyph( return g; } -/* This table can be used to find a coverage bit based on a charcode. later we can get default - * language and script from codepoint. */ +/** \} */ -typedef struct eUnicodeBlock { - unsigned int first; - unsigned int last; +/* -------------------------------------------------------------------- */ +/** \name Glyph Unicode Block Lookup + * + * This table can be used to find a coverage bit based on a charcode. + * Later we can get default language and script from `codepoint`. + */ + +struct UnicodeBlock { + uint first; + uint last; int coverage_bit; /* 0-122. -1 is N/A. */ /* Later we add primary script and language for Harfbuzz, data from * https://en.wikipedia.org/wiki/Unicode_block */ -} eUnicodeBlock; +}; -static eUnicodeBlock unicode_blocks[] = { +static const struct UnicodeBlock unicode_blocks[] = { /* Must be in ascending order by start of range. */ {0x0, 0x7F, 0}, /* Basic Latin. */ {0x80, 0xFF, 1}, /* Latin-1 Supplement. */ @@ -500,8 +556,10 @@ static eUnicodeBlock unicode_blocks[] = { {0xE0100, 0xE01EF, 91}, /* Variation Selectors. */ {0xF0000, 0x10FFFD, 90}}; /* Private Use Supplementary. */ -/* Find a unicode block that a charcode belongs to. */ -static eUnicodeBlock *blf_charcode_to_unicode_block(uint charcode) +/** + * Find a unicode block that a `charcode` belongs to. + */ +static const struct UnicodeBlock *blf_charcode_to_unicode_block(const uint charcode) { if (charcode < 0x80) { /* Shortcut to Basic Latin. */ @@ -512,14 +570,13 @@ static eUnicodeBlock *blf_charcode_to_unicode_block(uint charcode) int min = 0; int max = ARRAY_SIZE(unicode_blocks) - 1; - int mid; if (charcode < unicode_blocks[0].first || charcode > unicode_blocks[max].last) { return NULL; } while (max >= min) { - mid = (min + max) / 2; + const int mid = (min + max) / 2; if (charcode > unicode_blocks[mid].last) { min = mid + 1; } @@ -537,26 +594,26 @@ static eUnicodeBlock *blf_charcode_to_unicode_block(uint charcode) static int blf_charcode_to_coverage_bit(uint charcode) { int coverage_bit = -1; - eUnicodeBlock *block = blf_charcode_to_unicode_block(charcode); + const struct UnicodeBlock *block = blf_charcode_to_unicode_block(charcode); if (block) { coverage_bit = block->coverage_bit; } if (coverage_bit < 0 && charcode > 0xFFFF) { /* No coverage bit, but OpenType specs v.1.3+ says bit 57 implies that there - * are codepoints supported beyond the BMP, so only check fonts with this set. */ + * are code-points supported beyond the BMP, so only check fonts with this set. */ coverage_bit = 57; } return coverage_bit; } -static bool blf_font_has_coverage_bit(FontBLF *font, int coverage_bit) +static bool blf_font_has_coverage_bit(const FontBLF *font, int coverage_bit) { if (coverage_bit < 0) { return false; } - return (font->UnicodeRanges[(uint)coverage_bit >> 5] & (1u << ((uint)coverage_bit % 32))); + return (font->unicode_ranges[(uint)coverage_bit >> 5] & (1u << ((uint)coverage_bit % 32))); } /** @@ -565,11 +622,16 @@ static bool blf_font_has_coverage_bit(FontBLF *font, int coverage_bit) */ static FT_UInt blf_glyph_index_from_charcode(FontBLF **font, const uint charcode) { - FT_UInt glyph_index = FT_Get_Char_Index((*font)->face, charcode); + FT_UInt glyph_index = blf_get_char_index(*font, charcode); if (glyph_index) { return glyph_index; } + /* Only fonts managed by the cache can fallback. */ + if (!((*font)->flags & BLF_CACHED)) { + return 0; + } + /* Not found in main font, so look in the others. */ FontBLF *last_resort = NULL; int coverage_bit = blf_charcode_to_coverage_bit(charcode); @@ -584,7 +646,7 @@ static FT_UInt blf_glyph_index_from_charcode(FontBLF **font, const uint charcode continue; } if (coverage_bit < 0 || blf_font_has_coverage_bit(f, coverage_bit)) { - glyph_index = FT_Get_Char_Index(f->face, charcode); + glyph_index = blf_get_char_index(f, charcode); if (glyph_index) { *font = f; return glyph_index; @@ -592,9 +654,13 @@ static FT_UInt blf_glyph_index_from_charcode(FontBLF **font, const uint charcode } } +#ifdef DEBUG + printf("Unicode character U+%04X not found in loaded fonts. \n", charcode); +#endif + /* Not found in the stack, return from Last Resort if there is one. */ if (last_resort) { - glyph_index = FT_Get_Char_Index(last_resort->face, charcode); + glyph_index = blf_get_char_index(last_resort, charcode); if (glyph_index) { *font = last_resort; return glyph_index; @@ -604,6 +670,12 @@ static FT_UInt blf_glyph_index_from_charcode(FontBLF **font, const uint charcode return 0; } +/** \} */ + +/* -------------------------------------------------------------------- */ +/** \name Glyph Load + * \{ */ + /** * Load a glyph into the glyph slot of a font's face object. */ @@ -638,19 +710,19 @@ static FT_GlyphSlot blf_glyph_load(FontBLF *font, FT_UInt glyph_index) return NULL; } +/** \} */ + +/* -------------------------------------------------------------------- */ +/** \name Glyph Render + * \{ */ + /** * Convert a glyph from outlines to a bitmap that we can display. */ static bool blf_glyph_render_bitmap(FontBLF *font, FT_GlyphSlot glyph) { - int render_mode; - - if (font->flags & BLF_MONOCHROME) { - render_mode = FT_RENDER_MODE_MONO; - } - else { - render_mode = FT_RENDER_MODE_NORMAL; - } + const int render_mode = (font->flags & BLF_MONOCHROME) ? FT_RENDER_MODE_MONO : + FT_RENDER_MODE_NORMAL; /* Render the glyph curves to a bitmap. */ FT_Error err = FT_Render_Glyph(glyph, render_mode); @@ -689,17 +761,19 @@ static bool blf_glyph_render_bitmap(FontBLF *font, FT_GlyphSlot glyph) * * \param variations: Variation descriptors from `FT_Get_MM_Var`. * \param tag: Axis tag (4-character string as uint), like 'wght' - * \param axis_index: returns index of axis in variations array. + * \param r_axis_index: returns index of axis in variations array. */ -static FT_Var_Axis *blf_var_axis_by_tag(FT_MM_Var *variations, uint tag, int *axis_index) +static const FT_Var_Axis *blf_var_axis_by_tag(const FT_MM_Var *variations, + const uint tag, + int *r_axis_index) { - *axis_index = -1; + *r_axis_index = -1; if (!variations) { return NULL; } for (int i = 0; i < (int)variations->num_axis; i++) { if (variations->axis[i].tag == tag) { - *axis_index = i; + *r_axis_index = i; return &(variations->axis)[i]; break; } @@ -713,7 +787,7 @@ static FT_Var_Axis *blf_var_axis_by_tag(FT_MM_Var *variations, uint tag, int *ax * \param axis: Pointer to a design space axis structure. * \param factor: -1 to 1 with 0 meaning "default" */ -static FT_Fixed blf_factor_to_coordinate(FT_Var_Axis *axis, float factor) +static FT_Fixed blf_factor_to_coordinate(const FT_Var_Axis *axis, const float factor) { FT_Fixed value = axis->def; if (factor > 0) { @@ -734,13 +808,13 @@ static FT_Fixed blf_factor_to_coordinate(FT_Var_Axis *axis, float factor) * \param tag: Axis tag (4-character string as uint), like 'wght' * \param factor: -1 to 1 with 0 meaning "default" */ -static bool blf_glyph_set_variation_normalized(FontBLF *font, +static bool blf_glyph_set_variation_normalized(const FontBLF *font, FT_Fixed coords[], - uint tag, - float factor) + const uint tag, + const float factor) { int axis_index; - FT_Var_Axis *axis = blf_var_axis_by_tag(font->variations, tag, &axis_index); + const FT_Var_Axis *axis = blf_var_axis_by_tag(font->variations, tag, &axis_index); if (axis && (axis_index < BLF_VARIATIONS_MAX)) { coords[axis_index] = blf_factor_to_coordinate(axis, factor); return true; @@ -758,7 +832,7 @@ static bool blf_glyph_set_variation_normalized(FontBLF *font, static bool blf_glyph_set_variation_float(FontBLF *font, FT_Fixed coords[], uint tag, float value) { int axis_index; - FT_Var_Axis *axis = blf_var_axis_by_tag(font->variations, tag, &axis_index); + const FT_Var_Axis *axis = blf_var_axis_by_tag(font->variations, tag, &axis_index); if (axis && (axis_index < BLF_VARIATIONS_MAX)) { FT_Fixed int_value = to_16dot16(value); CLAMP(int_value, axis->minimum, axis->maximum); @@ -783,8 +857,8 @@ static bool blf_glyph_transform_weight(FT_GlyphSlot glyph, float factor, bool mo { if (glyph->format == FT_GLYPH_FORMAT_OUTLINE) { /* Fake bold if the font does not have this variable axis. */ - const FT_Pos average_width = FT_MulFix(glyph->face->units_per_EM, - glyph->face->size->metrics.x_scale); + const FontBLF *font = (FontBLF *)glyph->face->generic.data; + const FT_Pos average_width = font->ft_size->metrics.height; FT_Pos change = (FT_Pos)((float)average_width * factor * 0.1f); FT_Outline_EmboldenXY(&glyph->outline, change, change / 2); if (monospaced) { @@ -843,7 +917,8 @@ static bool blf_glyph_transform_width(FT_GlyphSlot glyph, float factor) static bool blf_glyph_transform_spacing(FT_GlyphSlot glyph, float factor) { if (glyph->advance.x > 0) { - const long int size = glyph->face->size->metrics.height; + const FontBLF *font = (FontBLF *)glyph->face->generic.data; + const long int size = font->ft_size->metrics.height; glyph->advance.x += (FT_Pos)(factor * (float)size / 6.0f); return true; } @@ -892,15 +967,11 @@ static FT_GlyphSlot blf_glyph_render(FontBLF *settings_font, int fixed_width) { if (glyph_font != settings_font) { - FT_Set_Char_Size(glyph_font->face, - 0, - ((FT_F26Dot6)(settings_font->size)) * 64, - settings_font->dpi, - settings_font->dpi); - glyph_font->size = settings_font->size; - glyph_font->dpi = settings_font->dpi; + blf_font_size(glyph_font, settings_font->size, settings_font->dpi); } + blf_ensure_size(glyph_font); + /* We need to keep track if changes are still needed. */ bool weight_done = false; bool slant_done = false; @@ -929,16 +1000,16 @@ static FT_GlyphSlot blf_glyph_render(FontBLF *settings_font, FT_Get_Var_Design_Coordinates(glyph_font->face, BLF_VARIATIONS_MAX, &coords[0]); /* Update design coordinates with new values. */ weight_done = blf_glyph_set_variation_normalized( - glyph_font, coords, blf_variation_axis_weight, weight); + glyph_font, coords, BLF_VARIATION_AXIS_WEIGHT, weight); slant_done = blf_glyph_set_variation_normalized( - glyph_font, coords, blf_variation_axis_slant, slant); + glyph_font, coords, BLF_VARIATION_AXIS_SLANT, slant); width_done = blf_glyph_set_variation_normalized( - glyph_font, coords, blf_variation_axis_width, width); + glyph_font, coords, BLF_VARIATION_AXIS_WIDTH, width); spacing_done = blf_glyph_set_variation_normalized( - glyph_font, coords, blf_variation_axis_spacing, spacing); + glyph_font, coords, BLF_VARIATION_AXIS_SPACING, spacing); /* Optical size, if available, is set to current font size. */ blf_glyph_set_variation_float( - glyph_font, coords, blf_variation_axis_optsize, settings_font->size); + glyph_font, coords, BLF_VARIATION_AXIS_OPTSIZE, settings_font->size); /* Save updated design coordinates. */ FT_Set_Var_Design_Coordinates(glyph_font->face, BLF_VARIATIONS_MAX, &coords[0]); } @@ -955,7 +1026,7 @@ static FT_GlyphSlot blf_glyph_render(FontBLF *settings_font, /* Fallback glyph transforms, but only if required and not yet done. */ if (weight != 0.0f && !weight_done) { - blf_glyph_transform_weight(glyph, weight, glyph->face->face_flags & FT_FACE_FLAG_FIXED_WIDTH); + blf_glyph_transform_weight(glyph, weight, FT_IS_FIXED_WIDTH(glyph_font)); } if (slant != 0.0f && !slant_done) { blf_glyph_transform_slant(glyph, slant); @@ -973,7 +1044,7 @@ static FT_GlyphSlot blf_glyph_render(FontBLF *settings_font, return NULL; } -GlyphBLF *blf_glyph_ensure(FontBLF *font, GlyphCacheBLF *gc, uint charcode) +GlyphBLF *blf_glyph_ensure(FontBLF *font, GlyphCacheBLF *gc, const uint charcode) { GlyphBLF *g = blf_glyph_cache_find_glyph(gc, charcode); if (g) { @@ -984,11 +1055,9 @@ GlyphBLF *blf_glyph_ensure(FontBLF *font, GlyphCacheBLF *gc, uint charcode) FontBLF *font_with_glyph = font; FT_UInt glyph_index = blf_glyph_index_from_charcode(&font_with_glyph, charcode); - /* Glyphs are dynamically created as needed by font rendering. this means that - * to make font rendering thread safe we have to do locking here. note that this - * must be a lock for the whole library and not just per font, because the font - * renderer uses a shared buffer internally. */ - BLI_spin_lock(font_with_glyph->ft_lib_mutex); + if (!blf_ensure_face(font_with_glyph)) { + return NULL; + } FT_GlyphSlot glyph = blf_glyph_render( font, font_with_glyph, glyph_index, charcode, gc->fixed_width); @@ -998,7 +1067,6 @@ GlyphBLF *blf_glyph_ensure(FontBLF *font, GlyphCacheBLF *gc, uint charcode) g = blf_glyph_cache_add_glyph(font, gc, glyph, charcode, glyph_index); } - BLI_spin_unlock(font_with_glyph->ft_lib_mutex); return g; } @@ -1047,7 +1115,7 @@ static void blf_glyph_calc_rect_shadow( /** \name Glyph Drawing * \{ */ -static void blf_texture_draw(const unsigned char color[4], +static void blf_texture_draw(const uchar color[4], const int glyph_size[2], const int offset, const int x1, @@ -1073,7 +1141,7 @@ static void blf_texture_draw(const unsigned char color[4], } } -static void blf_texture5_draw(const unsigned char color_in[4], +static void blf_texture5_draw(const uchar color_in[4], const int glyph_size[2], const int offset, const int x1, @@ -1089,7 +1157,7 @@ static void blf_texture5_draw(const unsigned char color_in[4], blf_texture_draw(color_in, glyph_size_flag, offset, x1, y1, x2, y2); } -static void blf_texture3_draw(const unsigned char color_in[4], +static void blf_texture3_draw(const uchar color_in[4], const int glyph_size[2], const int offset, const int x1, diff --git a/source/blender/blenfont/intern/blf_internal.h b/source/blender/blenfont/intern/blf_internal.h index 84037ff4bd0..39d3af22562 100644 --- a/source/blender/blenfont/intern/blf_internal.h +++ b/source/blender/blenfont/intern/blf_internal.h @@ -14,9 +14,16 @@ struct ResultBLF; struct rctf; struct rcti; -/* Max number of fonts in memory. Take care that every font has a glyph cache per size/dpi, +/* Max number of FontBLFs in memory. Take care that every font has a glyph cache per size/dpi, * so we don't need load the same font with different size, just load one and call BLF_size. */ -#define BLF_MAX_FONT 32 +#define BLF_MAX_FONT 64 + +/* Maximum number of opened FT_Face objects managed by cache. 0 is default of 2. */ +#define BLF_CACHE_MAX_FACES 4 +/* Maximum number of opened FT_Size objects managed by cache. 0 is default of 4 */ +#define BLF_CACHE_MAX_SIZES 8 +/* Maximum number of bytes to use for cached data nodes. 0 is default of 200,000. */ +#define BLF_CACHE_BYTES 400000 extern struct FontBLF *global_font[BLF_MAX_FONT]; @@ -39,12 +46,26 @@ void blf_font_exit(void); bool blf_font_id_is_valid(int fontid); +/** + * Return glyph id from char-code. + */ +uint blf_get_char_index(struct FontBLF *font, uint charcode); + +bool blf_ensure_face(struct FontBLF *font); +void blf_ensure_size(struct FontBLF *font); + void blf_draw_buffer__start(struct FontBLF *font); void blf_draw_buffer__end(void); +struct FontBLF *blf_font_new_ex(const char *name, + const char *filepath, + const unsigned char *mem, + size_t mem_size, + void *ft_library); + struct FontBLF *blf_font_new(const char *name, const char *filepath); -struct FontBLF *blf_font_new_from_mem(const char *name, const unsigned char *mem, int mem_size); -void blf_font_attach_from_mem(struct FontBLF *font, const unsigned char *mem, int mem_size); +struct FontBLF *blf_font_new_from_mem(const char *name, const unsigned char *mem, size_t mem_size); +void blf_font_attach_from_mem(struct FontBLF *font, const unsigned char *mem, size_t mem_size); /** * Change font's output size. Returns true if successful in changing the size. diff --git a/source/blender/blenfont/intern/blf_internal_types.h b/source/blender/blenfont/intern/blf_internal_types.h index 5b55f4af0b8..d64bd9c5452 100644 --- a/source/blender/blenfont/intern/blf_internal_types.h +++ b/source/blender/blenfont/intern/blf_internal_types.h @@ -12,16 +12,17 @@ #include FT_MULTIPLE_MASTERS_H /* Variable font support. */ -#define BLF_VARIATIONS_MAX 16 /* Maximum variation axes per font. */ +/** Maximum variation axes per font. */ +#define BLF_VARIATIONS_MAX 16 #define MAKE_DVAR_TAG(a, b, c, d) \ (((uint32_t)a << 24u) | ((uint32_t)b << 16u) | ((uint32_t)c << 8u) | ((uint32_t)d)) -#define blf_variation_axis_weight MAKE_DVAR_TAG('w', 'g', 'h', 't') /* 'wght' weight axis. */ -#define blf_variation_axis_slant MAKE_DVAR_TAG('s', 'l', 'n', 't') /* 'slnt' slant axis. */ -#define blf_variation_axis_width MAKE_DVAR_TAG('w', 'd', 't', 'h') /* 'wdth' width axis. */ -#define blf_variation_axis_spacing MAKE_DVAR_TAG('s', 'p', 'a', 'c') /* 'spac' spacing axis. */ -#define blf_variation_axis_optsize MAKE_DVAR_TAG('o', 'p', 's', 'z') /* 'opsz' optical size. */ +#define BLF_VARIATION_AXIS_WEIGHT MAKE_DVAR_TAG('w', 'g', 'h', 't') /* 'wght' weight axis. */ +#define BLF_VARIATION_AXIS_SLANT MAKE_DVAR_TAG('s', 'l', 'n', 't') /* 'slnt' slant axis. */ +#define BLF_VARIATION_AXIS_WIDTH MAKE_DVAR_TAG('w', 'd', 't', 'h') /* 'wdth' width axis. */ +#define BLF_VARIATION_AXIS_SPACING MAKE_DVAR_TAG('s', 'p', 'a', 'c') /* 'spac' spacing axis. */ +#define BLF_VARIATION_AXIS_OPTSIZE MAKE_DVAR_TAG('o', 'p', 's', 'z') /* 'opsz' optical size. */ /* -------------------------------------------------------------------- */ /** \name Sub-Pixel Offset & Utilities @@ -38,10 +39,12 @@ typedef int32_t ft_pix; /* Macros copied from `include/freetype/internal/ftobjs.h`. */ -/* FIXME(@campbellbarton): Follow rounding from Blender 3.1x and older. +/** + * FIXME(@campbellbarton): Follow rounding from Blender 3.1x and older. * This is what users will expect and changing this creates wider spaced text. * Use this macro to communicate that rounding should be used, using floor is to avoid - * user visible changes, which can be reviewed and handled separately. */ + * user visible changes, which can be reviewed and handled separately. + */ #define USE_LEGACY_SPACING #define FT_PIX_FLOOR(x) ((x) & ~63) @@ -85,7 +88,7 @@ BLI_INLINE ft_pix ft_pix_from_float(float v) BLI_INLINE ft_pix ft_pix_round_advance(ft_pix v, ft_pix step) { - /* See #USE_LEGACY_SPACING, rounding logic could change here. */ + /** See #USE_LEGACY_SPACING, rounding logic could change here. */ return FT_PIX_DEFAULT_ROUNDING(v) + FT_PIX_DEFAULT_ROUNDING(step); } @@ -97,24 +100,27 @@ BLI_INLINE ft_pix ft_pix_round_advance(ft_pix v, ft_pix step) #define BLF_BATCH_DRAW_LEN_MAX 2048 /* in glyph */ -/* Number of characters in GlyphCacheBLF.glyph_ascii_table. */ +/** Number of characters in #GlyphCacheBLF.glyph_ascii_table. */ #define GLYPH_ASCII_TABLE_SIZE 128 -/* Number of characters in KerningCacheBLF.table. */ +/** Number of characters in #KerningCacheBLF.table. */ #define KERNING_CACHE_TABLE_SIZE 128 -/* A value in the kerning cache that indicates it is not yet set. */ +/** A value in the kerning cache that indicates it is not yet set. */ #define KERNING_ENTRY_UNSET INT_MAX typedef struct BatchBLF { - struct FontBLF *font; /* can only batch glyph from the same font */ + /** Can only batch glyph from the same font. */ + struct FontBLF *font; struct GPUBatch *batch; struct GPUVertBuf *verts; struct GPUVertBufRaw pos_step, col_step, offset_step, glyph_size_step; unsigned int pos_loc, col_loc, offset_loc, glyph_size_loc; unsigned int glyph_len; - int ofs[2]; /* copy of font->pos */ - float mat[4][4]; /* previous call modelmatrix. */ + /** Copy of `font->pos`. */ + int ofs[2]; + /* Previous call `modelmatrix`. */ + float mat[4][4]; bool enabled, active, simple_shader; struct GlyphCacheBLF *glyph_cache; } BatchBLF; @@ -133,11 +139,12 @@ typedef struct GlyphCacheBLF { struct GlyphCacheBLF *next; struct GlyphCacheBLF *prev; - /* font size. */ + /** Font size. */ float size; - /* and DPI. */ + /** DPI. */ unsigned int dpi; + float char_weight; float char_slant; float char_width; @@ -146,16 +153,16 @@ typedef struct GlyphCacheBLF { bool bold; bool italic; - /* Column width when printing monospaced. */ + /** Column width when printing monospaced. */ int fixed_width; - /* and the glyphs. */ + /** The glyphs. */ ListBase bucket[257]; - /* fast ascii lookup */ + /** Fast ascii lookup */ struct GlyphBLF *glyph_ascii_table[GLYPH_ASCII_TABLE_SIZE]; - /* texture array, to draw the glyphs. */ + /** Texture array, to draw the glyphs. */ GPUTexture *texture; char *bitmap_result; int bitmap_len; @@ -168,13 +175,13 @@ typedef struct GlyphBLF { struct GlyphBLF *next; struct GlyphBLF *prev; - /* and the character, as UTF-32 */ + /** The character, as UTF-32. */ unsigned int c; - /* freetype2 index, to speed-up the search. */ + /** Freetype2 index, to speed-up the search. */ FT_UInt idx; - /* glyph box. */ + /** Glyph bounding-box. */ ft_pix box_xmin; ft_pix box_xmax; ft_pix box_ymin; @@ -182,19 +189,20 @@ typedef struct GlyphBLF { ft_pix advance_x; - /* The difference in bearings when hinting is active, zero otherwise. */ + /** The difference in bearings when hinting is active, zero otherwise. */ ft_pix lsb_delta; ft_pix rsb_delta; - /* position inside the texture where this glyph is store. */ + /** Position inside the texture where this glyph is store. */ int offset; - /* Bitmap data, from freetype. Take care that this + /** + * Bitmap data, from freetype. Take care that this * can be NULL. */ unsigned char *bitmap; - /* Glyph width and height. */ + /** Glyph width and height. */ int dims[2]; int pitch; @@ -209,52 +217,57 @@ typedef struct GlyphBLF { } GlyphBLF; typedef struct FontBufInfoBLF { - /* for draw to buffer, always set this to NULL after finish! */ + /** For draw to buffer, always set this to NULL after finish! */ float *fbuf; - /* the same but unsigned char */ + /** The same but unsigned char. */ unsigned char *cbuf; /** Buffer size, keep signed so comparisons with negative values work. */ int dims[2]; - /* number of channels. */ + /** Number of channels. */ int ch; - /* display device used for color management */ + /** Display device used for color management. */ struct ColorManagedDisplay *display; - /* and the color, the alphas is get from the glyph! - * color is sRGB space */ + /** The color, the alphas is get from the glyph! (color is sRGB space). */ float col_init[4]; - /* cached conversion from 'col_init' */ + /** Cached conversion from 'col_init'. */ unsigned char col_char[4]; float col_float[4]; } FontBufInfoBLF; typedef struct FontBLF { - /* font name. */ + /** Font name. */ char *name; - /* # of times this font was loaded */ - unsigned int reference_count; - - /** File-path or NULL. */ + /** Full path to font file or NULL if from memory. */ char *filepath; - /* Copied from the SFNT OS/2 table. Bit flags for unicode blocks and ranges + /** Pointer to in-memory font, or NULL if from file. */ + void *mem; + size_t mem_size; + + /** + * Copied from the SFNT OS/2 table. Bit flags for unicode blocks and ranges * considered "functional". Cached here because face might not always exist. - * See: https://docs.microsoft.com/en-us/typography/opentype/spec/os2#ur */ - uint UnicodeRanges[4]; + * See: https://docs.microsoft.com/en-us/typography/opentype/spec/os2#ur + */ + uint unicode_ranges[4]; + + /** Number of times this font was loaded. */ + unsigned int reference_count; - /* aspect ratio or scale. */ + /** Aspect ratio or scale. */ float aspect[3]; - /* initial position for draw the text. */ + /** Initial position for draw the text. */ int pos[3]; - /* angle in radians. */ + /** Angle in radians. */ float angle; #if 0 /* BLF_BLUR_ENABLE */ @@ -262,49 +275,50 @@ typedef struct FontBLF { int blur; #endif - /* shadow level. */ + /** Shadow level. */ int shadow; - /* and shadow offset. */ + /** And shadow offset. */ int shadow_x; int shadow_y; - /* shadow color. */ + /** Shadow color. */ unsigned char shadow_color[4]; - /* main text color. */ + /** Main text color. */ unsigned char color[4]; - /* Multiplied this matrix with the current one before - * draw the text! see blf_draw__start. + /** + * Multiplied this matrix with the current one before draw the text! + * see #blf_draw_gl__start. */ float m[16]; - /* clipping rectangle. */ + /** Clipping rectangle. */ rcti clip_rec; - /* the width to wrap the text, see BLF_WORD_WRAP */ + /** The width to wrap the text, see #BLF_WORD_WRAP. */ int wrap_width; - /* Font DPI (default 72). */ + /** Font DPI (default 72). */ unsigned int dpi; - /* font size. */ + /** Font size. */ float size; - /* Axes data for Adobe MM, TrueType GX, or OpenType variation fonts. */ + /** Axes data for Adobe MM, TrueType GX, or OpenType variation fonts. */ FT_MM_Var *variations; - /* Character variation; 0=default, -1=min, +1=max. */ + /** Character variation; 0=default, -1=min, +1=max. */ float char_weight; float char_slant; float char_width; float char_spacing; - /* max texture size. */ + /** Max texture size. */ int tex_size_max; - /* font options. */ + /** Font options. */ int flags; /** @@ -313,29 +327,32 @@ typedef struct FontBLF { */ ListBase cache; - /* Cache of unscaled kerning values. Will be NULL if font does not have kerning. */ + /** Cache of unscaled kerning values. Will be NULL if font does not have kerning. */ KerningCacheBLF *kerning_cache; - /* freetype2 lib handle. */ + /** Freetype2 lib handle. */ FT_Library ft_lib; - /* Mutex lock for library */ - SpinLock *ft_lib_mutex; - - /* freetype2 face. */ + /** Freetype2 face. */ FT_Face face; - /* data for buffer usage (drawing into a texture buffer) */ + /** Point to face->size or to cache's size. */ + FT_Size ft_size; + + /** Copy of the font->face->face_flags, in case we don't have a face loaded. */ + FT_Long face_flags; + + /** Data for buffer usage (drawing into a texture buffer) */ FontBufInfoBLF buf_info; - /* Mutex lock for glyph cache. */ - SpinLock *glyph_cache_mutex; + /** Mutex lock for glyph cache. */ + ThreadMutex glyph_cache_mutex; } FontBLF; typedef struct DirBLF { struct DirBLF *next; struct DirBLF *prev; - /* full path where search fonts. */ + /** Full path where search fonts. */ char *path; } DirBLF; diff --git a/source/blender/blenfont/intern/blf_thumbs.c b/source/blender/blenfont/intern/blf_thumbs.c index 9460e9413d1..1670674ebba 100644 --- a/source/blender/blenfont/intern/blf_thumbs.c +++ b/source/blender/blenfont/intern/blf_thumbs.c @@ -32,26 +32,34 @@ void BLF_thumb_preview(const char *filepath, const char **draw_str, const char **i18n_draw_str, - const unsigned char draw_str_lines, + const uchar draw_str_lines, const float font_color[4], const int font_size, - unsigned char *buf, - int w, - int h, - int channels) + uchar *buf, + const int w, + const int h, + const int channels) { - const unsigned int dpi = 72; + const uint dpi = 72; const int font_size_min = 6; int font_size_curr; /* shrink 1/th each line */ int font_shrink = 4; - FontBLF *font; + /* While viewing thumbnails in font directories this function can be called simultaneously from a + * greater number of threads than we want the FreeType cache to keep open at a time. Therefore + * pass own FT_Library to font creation so that it is not managed by the FreeType cache system. + */ - /* Create a new blender font obj and fill it with default values */ - font = blf_font_new("thumb_font", filepath); + FT_Library ft_library = NULL; + if (FT_Init_FreeType(&ft_library) != FT_Err_Ok) { + return; + } + + FontBLF *font = blf_font_new_ex("thumb_font", filepath, NULL, 0, ft_library); if (!font) { printf("Info: Can't load font '%s', no preview possible\n", filepath); + FT_Done_FreeType(ft_library); return; } @@ -86,7 +94,7 @@ void BLF_thumb_preview(const char *filepath, font->pos[1] -= (int)((float)blf_font_ascender(font) * 1.1f); - /* We fallback to default english strings in case not enough chars are available in current + /* We fallback to default English strings in case not enough chars are available in current * font for given translated string (useful in non-Latin i18n context, like Chinese, * since many fonts will then show nothing but ugly 'missing char' in their preview). * Does not handle all cases, but much better than nothing. @@ -102,4 +110,5 @@ void BLF_thumb_preview(const char *filepath, blf_draw_buffer__end(); blf_font_free(font); + FT_Done_FreeType(ft_library); } diff --git a/source/blender/blenkernel/BKE_DerivedMesh.h b/source/blender/blenkernel/BKE_DerivedMesh.h index 4274ca97fd1..da1e45ababd 100644 --- a/source/blender/blenkernel/BKE_DerivedMesh.h +++ b/source/blender/blenkernel/BKE_DerivedMesh.h @@ -141,14 +141,6 @@ struct DerivedMesh { void (*copyLoopArray)(DerivedMesh *dm, struct MLoop *r_loop); void (*copyPolyArray)(DerivedMesh *dm, struct MPoly *r_poly); - /** Return a copy of all verts/edges/faces from the derived mesh - * it is the caller's responsibility to free the returned pointer - */ - struct MVert *(*dupVertArray)(DerivedMesh *dm); - struct MEdge *(*dupEdgeArray)(DerivedMesh *dm); - struct MLoop *(*dupLoopArray)(DerivedMesh *dm); - struct MPoly *(*dupPolyArray)(DerivedMesh *dm); - /** Return a pointer to the entire array of vert/edge/face custom data * from the derived mesh (this gives a pointer to the actual data, not * a copy) @@ -253,11 +245,6 @@ void DM_copy_vert_data(struct DerivedMesh *source, int dest_index, int count); -/** - * Sets up mpolys for a DM based on face iterators in source. - */ -void DM_DupPolys(DerivedMesh *source, DerivedMesh *target); - /** * Ensure the array is large enough. * diff --git a/source/blender/blenkernel/BKE_appdir.h b/source/blender/blenkernel/BKE_appdir.h index dcacc2ca7b3..0f00ab9c321 100644 --- a/source/blender/blenkernel/BKE_appdir.h +++ b/source/blender/blenkernel/BKE_appdir.h @@ -56,7 +56,7 @@ const char *BKE_appdir_folder_home(void); * * \returns True if the path is valid and points to an existing directory. */ -bool BKE_appdir_folder_documents(char *dir); +bool BKE_appdir_folder_documents(char *dir) ATTR_NONNULL(1) ATTR_WARN_UNUSED_RESULT; /** * Get the user's cache directory, i.e. * - Linux: `$HOME/.cache/blender/` @@ -66,7 +66,7 @@ bool BKE_appdir_folder_documents(char *dir); * \returns True if the path is valid. It doesn't create or checks format * if the `blender` folder exists. It does check if the parent of the path exists. */ -bool BKE_appdir_folder_caches(char *r_path, size_t path_len); +bool BKE_appdir_folder_caches(char *r_path, size_t path_len) ATTR_NONNULL(1); /** * Get a folder out of the \a folder_id presets for paths. * @@ -75,15 +75,17 @@ bool BKE_appdir_folder_caches(char *r_path, size_t path_len); * \return The path if found, NULL string if not. */ bool BKE_appdir_folder_id_ex(int folder_id, const char *subfolder, char *path, size_t path_len); -const char *BKE_appdir_folder_id(int folder_id, const char *subfolder); +const char *BKE_appdir_folder_id(int folder_id, const char *subfolder) ATTR_WARN_UNUSED_RESULT; /** * Returns the path to a folder in the user area, creating it if it doesn't exist. */ -const char *BKE_appdir_folder_id_create(int folder_id, const char *subfolder); +const char *BKE_appdir_folder_id_create(int folder_id, + const char *subfolder) ATTR_WARN_UNUSED_RESULT; /** * Returns the path to a folder in the user area without checking that it actually exists first. */ -const char *BKE_appdir_folder_id_user_notest(int folder_id, const char *subfolder); +const char *BKE_appdir_folder_id_user_notest(int folder_id, + const char *subfolder) ATTR_WARN_UNUSED_RESULT; /** * Returns the path of the top-level version-specific local, user or system directory. * If check_is_dir, then the result will be NULL if the directory doesn't exist. @@ -99,23 +101,24 @@ bool BKE_appdir_app_is_portable_install(void); * Return true if templates exist */ bool BKE_appdir_app_template_any(void); -bool BKE_appdir_app_template_id_search(const char *app_template, char *path, size_t path_len); -bool BKE_appdir_app_template_has_userpref(const char *app_template); -void BKE_appdir_app_templates(struct ListBase *templates); +bool BKE_appdir_app_template_id_search(const char *app_template, char *path, size_t path_len) + ATTR_NONNULL(1); +bool BKE_appdir_app_template_has_userpref(const char *app_template) ATTR_NONNULL(1); +void BKE_appdir_app_templates(struct ListBase *templates) ATTR_NONNULL(1); /** * Initialize path to program executable. */ -void BKE_appdir_program_path_init(const char *argv0); +void BKE_appdir_program_path_init(const char *argv0) ATTR_NONNULL(1); /** * Path to executable */ -const char *BKE_appdir_program_path(void); +const char *BKE_appdir_program_path(void) ATTR_WARN_UNUSED_RESULT ATTR_RETURNS_NONNULL; /** * Path to directory of executable */ -const char *BKE_appdir_program_dir(void); +const char *BKE_appdir_program_dir(void) ATTR_WARN_UNUSED_RESULT ATTR_RETURNS_NONNULL; /** * Gets a good default directory for fonts. @@ -128,7 +131,7 @@ bool BKE_appdir_font_folder_default(char *dir); bool BKE_appdir_program_python_search(char *fullpath, size_t fullpath_len, int version_major, - int version_minor); + int version_minor) ATTR_NONNULL(1); /** * Initialize path to temporary directory. @@ -138,11 +141,11 @@ void BKE_tempdir_init(const char *userdir); /** * Path to persistent temporary directory (with trailing slash) */ -const char *BKE_tempdir_base(void); +const char *BKE_tempdir_base(void) ATTR_WARN_UNUSED_RESULT ATTR_RETURNS_NONNULL; /** * Path to temporary directory (with trailing slash) */ -const char *BKE_tempdir_session(void); +const char *BKE_tempdir_session(void) ATTR_WARN_UNUSED_RESULT ATTR_RETURNS_NONNULL; /** * Delete content of this instance's temp dir. */ diff --git a/source/blender/blenkernel/BKE_attribute.hh b/source/blender/blenkernel/BKE_attribute.hh index b92d0d4326b..7b13b8a2b09 100644 --- a/source/blender/blenkernel/BKE_attribute.hh +++ b/source/blender/blenkernel/BKE_attribute.hh @@ -2,6 +2,8 @@ #pragma once +#include + #include "BLI_color.hh" #include "BLI_function_ref.hh" #include "BLI_generic_span.hh" @@ -14,6 +16,10 @@ struct Mesh; struct PointCloud; +namespace blender::fn { +class MultiFunction; +class GField; +} // namespace blender::fn namespace blender::bke { @@ -71,8 +77,13 @@ struct AttributeKind { */ struct AttributeInit { enum class Type { - Default, + /** #AttributeInitConstruct. */ + Construct, + /** #AttributeInitDefaultValue. */ + DefaultValue, + /** #AttributeInitVArray. */ VArray, + /** #AttributeInitMoveArray. */ MoveArray, }; Type type; @@ -82,11 +93,20 @@ struct AttributeInit { }; /** - * Create an attribute using the default value for the data type. - * The default values may depend on the attribute provider implementation. + * Default construct new attribute values. Does nothing for trivial types. This should be used + * if all attribute element values will be set by the caller after creating the attribute. + */ +struct AttributeInitConstruct : public AttributeInit { + AttributeInitConstruct() : AttributeInit(Type::Construct) + { + } +}; + +/** + * Create an attribute using the default value for the data type (almost always "zero"). */ -struct AttributeInitDefault : public AttributeInit { - AttributeInitDefault() : AttributeInit(Type::Default) +struct AttributeInitDefaultValue : public AttributeInit { + AttributeInitDefaultValue() : AttributeInit(Type::DefaultValue) { } }; @@ -94,14 +114,11 @@ struct AttributeInitDefault : public AttributeInit { /** * Create an attribute by copying data from an existing virtual array. The virtual array * must have the same type as the newly created attribute. - * - * Note that this can be used to fill the new attribute with the default */ struct AttributeInitVArray : public AttributeInit { - blender::GVArray varray; + GVArray varray; - AttributeInitVArray(blender::GVArray varray) - : AttributeInit(Type::VArray), varray(std::move(varray)) + AttributeInitVArray(GVArray varray) : AttributeInit(Type::VArray), varray(std::move(varray)) { } }; @@ -117,10 +134,10 @@ struct AttributeInitVArray : public AttributeInit { * The array must be allocated with MEM_*, since `attribute_try_create` will free the array if it * can't be used directly, and that is generally how Blender expects custom data to be allocated. */ -struct AttributeInitMove : public AttributeInit { +struct AttributeInitMoveArray : public AttributeInit { void *data = nullptr; - AttributeInitMove(void *data) : AttributeInit(Type::MoveArray), data(data) + AttributeInitMoveArray(void *data) : AttributeInit(Type::MoveArray), data(data) { } }; @@ -150,7 +167,28 @@ template struct AttributeReader { }; /** - * Result when looking up an attribute from some geometry with read an write access. After writing + * A utility to make sure attribute values are valid, for attributes like "material_index" which + * can only be positive, or attributes that represent enum options. This is usually only necessary + * when writing attributes from an untrusted/arbitrary user input. + */ +struct AttributeValidator { + /** + * Single input, single output function that corrects attribute values if necessary. + */ + const fn::MultiFunction *function; + + operator bool() const + { + return this->function != nullptr; + } + /** + * Return a field that creates corrected attribute values. + */ + fn::GField validate_field_if_necessary(const fn::GField &field) const; +}; + +/** + * Result when looking up an attribute from some geometry with read and write access. After writing * to the attribute, the #finish method has to be called. This may invalidate caches based on this * attribute. */ @@ -226,7 +264,9 @@ template struct SpanAttributeWriter { */ void finish() { - this->span.save(); + if (this->span.varray()) { + this->span.save(); + } if (this->tag_modified_fn) { this->tag_modified_fn(); } @@ -301,7 +341,9 @@ struct GSpanAttributeWriter { void finish() { - this->span.save(); + if (this->span.varray()) { + this->span.save(); + } if (this->tag_modified_fn) { this->tag_modified_fn(); } @@ -330,7 +372,7 @@ struct AttributeAccessorFunctions { eAttrDomain to_domain); bool (*for_all)(const void *owner, FunctionRef fn); - + AttributeValidator (*lookup_validator)(const void *owner, const AttributeIDRef &attribute_id); GAttributeWriter (*lookup_for_write)(void *owner, const AttributeIDRef &attribute_id); bool (*remove)(void *owner, const AttributeIDRef &attribute_id); bool (*add)(void *owner, @@ -351,8 +393,9 @@ class AttributeAccessor { /** * The data that actually owns the attributes, for example, a pointer to a #Mesh or #PointCloud * Most commonly this is a pointer to a #Mesh or #PointCloud. - * Under some circumstances this can be null. In that case most methods can't be used. Just e.g. - * the #domain_size method works and returns 0 for every domain. + * Under some circumstances this can be null. In that case most methods can't be used. Allowed + * methods are #domain_size, #for_all and #is_builtin. We could potentially make these methods + * accessible without #AttributeAccessor and then #owner_ could always be non-null. * * \note This class cannot modify the owner's attributes, but the pointer is still non-const, so * this class can be a base class for the mutable version. @@ -483,6 +526,14 @@ class AttributeAccessor { return VArray::ForSingle(default_value, this->domain_size(domain)); } + /** + * Same as the generic version above, but should be used when the type is known at compile time. + */ + AttributeValidator lookup_validator(const AttributeIDRef &attribute_id) const + { + return fn_->lookup_validator(owner_, attribute_id); + } + /** * Interpolate data from one domain to another. */ @@ -509,7 +560,10 @@ class AttributeAccessor { */ bool for_all(const AttributeForeachCallback fn) const { - return fn_->for_all(owner_, fn); + if (owner_ != nullptr) { + return fn_->for_all(owner_, fn); + } + return true; } /** @@ -533,10 +587,12 @@ class MutableAttributeAccessor : public AttributeAccessor { * Get a writable attribute or none if it does not exist. * Make sure to call #finish after changes are done. */ - GAttributeWriter lookup_for_write(const AttributeIDRef &attribute_id) - { - return fn_->lookup_for_write(owner_, attribute_id); - } + GAttributeWriter lookup_for_write(const AttributeIDRef &attribute_id); + + /** + * Same as above, but returns a type that makes it easier to work with the attribute as a span. + */ + GSpanAttributeWriter lookup_for_write_span(const AttributeIDRef &attribute_id); /** * Get a writable attribute or non if it does not exist. @@ -554,6 +610,19 @@ class MutableAttributeAccessor : public AttributeAccessor { return attribute.typed(); } + /** + * Same as above, but returns a type that makes it easier to work with the attribute as a span. + */ + template + SpanAttributeWriter lookup_for_write_span(const AttributeIDRef &attribute_id) + { + AttributeWriter attribute = this->lookup_for_write(attribute_id); + if (attribute) { + return SpanAttributeWriter{std::move(attribute), true}; + } + return {}; + } + /** * Create a new attribute. * \return True, when a new attribute has been created. False, when it's not possible to create @@ -576,7 +645,7 @@ class MutableAttributeAccessor : public AttributeAccessor { const AttributeIDRef &attribute_id, const eAttrDomain domain, const eCustomDataType data_type, - const AttributeInit &initializer = AttributeInitDefault()); + const AttributeInit &initializer = AttributeInitDefaultValue()); /** * Same as above, but returns a type that makes it easier to work with the attribute as a span. @@ -587,7 +656,7 @@ class MutableAttributeAccessor : public AttributeAccessor { const AttributeIDRef &attribute_id, const eAttrDomain domain, const eCustomDataType data_type, - const AttributeInit &initializer = AttributeInitDefault()); + const AttributeInit &initializer = AttributeInitDefaultValue()); /** * Same as above, but should be used when the type is known at compile time. @@ -596,7 +665,7 @@ class MutableAttributeAccessor : public AttributeAccessor { AttributeWriter lookup_or_add_for_write( const AttributeIDRef &attribute_id, const eAttrDomain domain, - const AttributeInit &initializer = AttributeInitDefault()) + const AttributeInit &initializer = AttributeInitDefaultValue()) { const CPPType &cpp_type = CPPType::get(); const eCustomDataType data_type = cpp_type_to_custom_data_type(cpp_type); @@ -610,7 +679,7 @@ class MutableAttributeAccessor : public AttributeAccessor { SpanAttributeWriter lookup_or_add_for_write_span( const AttributeIDRef &attribute_id, const eAttrDomain domain, - const AttributeInit &initializer = AttributeInitDefault()) + const AttributeInit &initializer = AttributeInitDefaultValue()) { AttributeWriter attribute = this->lookup_or_add_for_write( attribute_id, domain, initializer); @@ -627,6 +696,8 @@ class MutableAttributeAccessor : public AttributeAccessor { * The "only" in the name indicates that the caller should not read existing values from the * span. If the attribute is not stored as span internally, the existing values won't be copied * over to the span. + * + * For trivial types, the values in a newly created attribute will not be initialized. */ GSpanAttributeWriter lookup_or_add_for_write_only_span(const AttributeIDRef &attribute_id, const eAttrDomain domain, @@ -639,7 +710,9 @@ class MutableAttributeAccessor : public AttributeAccessor { SpanAttributeWriter lookup_or_add_for_write_only_span(const AttributeIDRef &attribute_id, const eAttrDomain domain) { - AttributeWriter attribute = this->lookup_or_add_for_write(attribute_id, domain); + AttributeWriter attribute = this->lookup_or_add_for_write( + attribute_id, domain, AttributeInitConstruct()); + if (attribute) { return SpanAttributeWriter{std::move(attribute), false}; } @@ -662,6 +735,35 @@ class MutableAttributeAccessor : public AttributeAccessor { void remove_anonymous(); }; +struct AttributeTransferData { + /* Expect that if an attribute exists, it is stored as a contiguous array internally anyway. */ + GVArraySpan src; + AttributeMetaData meta_data; + bke::GSpanAttributeWriter dst; +}; +/** + * Retrieve attribute arrays and writers for attributes that should be transferred between + * data-blocks of the same type. + */ +Vector retrieve_attributes_for_transfer( + const bke::AttributeAccessor src_attributes, + bke::MutableAttributeAccessor dst_attributes, + eAttrDomainMask domain_mask, + const Set &skip = {}); + +/** + * Copy attributes for the domain based on the elementwise mask. + * + * \param mask_indices: Indexed elements to copy from the source data-block. + * \param domain: Attribute domain to transfer. + * \param skip: Named attributes to ignore/skip. + */ +void copy_attribute_domain(AttributeAccessor src_attributes, + MutableAttributeAccessor dst_attributes, + IndexMask selection, + eAttrDomain domain, + const Set &skip = {}); + bool allow_procedural_attribute_access(StringRef attribute_name); extern const char *no_procedural_access_message; @@ -722,20 +824,9 @@ class CustomDataAttributes { bool create_by_move(const AttributeIDRef &attribute_id, eCustomDataType data_type, void *buffer); bool remove(const AttributeIDRef &attribute_id); - /** - * Change the order of the attributes to match the order of IDs in the argument. - */ - void reorder(Span new_order); - bool foreach_attribute(const AttributeForeachCallback callback, eAttrDomain domain) const; }; -AttributeAccessor mesh_attributes(const Mesh &mesh); -MutableAttributeAccessor mesh_attributes_for_write(Mesh &mesh); - -AttributeAccessor pointcloud_attributes(const PointCloud &pointcloud); -MutableAttributeAccessor pointcloud_attributes_for_write(PointCloud &pointcloud); - /* -------------------------------------------------------------------- */ /** \name #AttributeIDRef Inline Methods * \{ */ diff --git a/source/blender/blenkernel/BKE_attribute_math.hh b/source/blender/blenkernel/BKE_attribute_math.hh index 01c2ef988f2..abd8b33b260 100644 --- a/source/blender/blenkernel/BKE_attribute_math.hh +++ b/source/blender/blenkernel/BKE_attribute_math.hh @@ -45,6 +45,58 @@ inline void convert_to_static_type(const eCustomDataType data_type, const Func & convert_to_static_type(cpp_type, func); } +/* -------------------------------------------------------------------- */ +/** \name Mix two values of the same type. + * + * This is just basic linear interpolation. + * \{ */ + +template T mix2(float factor, const T &a, const T &b); + +template<> inline bool mix2(const float factor, const bool &a, const bool &b) +{ + return ((1.0f - factor) * a + factor * b) >= 0.5f; +} + +template<> inline int8_t mix2(const float factor, const int8_t &a, const int8_t &b) +{ + return static_cast(std::round((1.0f - factor) * a + factor * b)); +} + +template<> inline int mix2(const float factor, const int &a, const int &b) +{ + return static_cast(std::round((1.0f - factor) * a + factor * b)); +} + +template<> inline float mix2(const float factor, const float &a, const float &b) +{ + return (1.0f - factor) * a + factor * b; +} + +template<> inline float2 mix2(const float factor, const float2 &a, const float2 &b) +{ + return math::interpolate(a, b, factor); +} + +template<> inline float3 mix2(const float factor, const float3 &a, const float3 &b) +{ + return math::interpolate(a, b, factor); +} + +template<> +inline ColorGeometry4f mix2(const float factor, const ColorGeometry4f &a, const ColorGeometry4f &b) +{ + return math::interpolate(a, b, factor); +} + +template<> +inline ColorGeometry4b mix2(const float factor, const ColorGeometry4b &a, const ColorGeometry4b &b) +{ + return math::interpolate(a, b, factor); +} + +/** \} */ + /* -------------------------------------------------------------------- */ /** \name Mix three values of the same type. * @@ -117,53 +169,85 @@ inline ColorGeometry4b mix3(const float3 &weights, /** \} */ /* -------------------------------------------------------------------- */ -/** \name Mix two values of the same type. +/** \name Mix four values of the same type. * - * This is just basic linear interpolation. * \{ */ -template T mix2(float factor, const T &a, const T &b); +template +T mix4(const float4 &weights, const T &v0, const T &v1, const T &v2, const T &v3); -template<> inline bool mix2(const float factor, const bool &a, const bool &b) +template<> +inline int8_t mix4( + const float4 &weights, const int8_t &v0, const int8_t &v1, const int8_t &v2, const int8_t &v3) { - return ((1.0f - factor) * a + factor * b) >= 0.5f; + return static_cast( + std::round(weights.x * v0 + weights.y * v1 + weights.z * v2 + weights.w * v3)); } -template<> inline int8_t mix2(const float factor, const int8_t &a, const int8_t &b) +template<> +inline bool mix4( + const float4 &weights, const bool &v0, const bool &v1, const bool &v2, const bool &v3) { - return static_cast(std::round((1.0f - factor) * a + factor * b)); + return (weights.x * v0 + weights.y * v1 + weights.z * v2 + weights.w * v3) >= 0.5f; } -template<> inline int mix2(const float factor, const int &a, const int &b) +template<> +inline int mix4(const float4 &weights, const int &v0, const int &v1, const int &v2, const int &v3) { - return static_cast(std::round((1.0f - factor) * a + factor * b)); + return static_cast( + std::round(weights.x * v0 + weights.y * v1 + weights.z * v2 + weights.w * v3)); } -template<> inline float mix2(const float factor, const float &a, const float &b) +template<> +inline float mix4( + const float4 &weights, const float &v0, const float &v1, const float &v2, const float &v3) { - return (1.0f - factor) * a + factor * b; + return weights.x * v0 + weights.y * v1 + weights.z * v2 + weights.w * v3; } -template<> inline float2 mix2(const float factor, const float2 &a, const float2 &b) +template<> +inline float2 mix4( + const float4 &weights, const float2 &v0, const float2 &v1, const float2 &v2, const float2 &v3) { - return math::interpolate(a, b, factor); + return weights.x * v0 + weights.y * v1 + weights.z * v2 + weights.w * v3; } -template<> inline float3 mix2(const float factor, const float3 &a, const float3 &b) +template<> +inline float3 mix4( + const float4 &weights, const float3 &v0, const float3 &v1, const float3 &v2, const float3 &v3) { - return math::interpolate(a, b, factor); + return weights.x * v0 + weights.y * v1 + weights.z * v2 + weights.w * v3; } template<> -inline ColorGeometry4f mix2(const float factor, const ColorGeometry4f &a, const ColorGeometry4f &b) +inline ColorGeometry4f mix4(const float4 &weights, + const ColorGeometry4f &v0, + const ColorGeometry4f &v1, + const ColorGeometry4f &v2, + const ColorGeometry4f &v3) { - return math::interpolate(a, b, factor); + ColorGeometry4f result; + interp_v4_v4v4v4v4(result, v0, v1, v2, v3, weights); + return result; } template<> -inline ColorGeometry4b mix2(const float factor, const ColorGeometry4b &a, const ColorGeometry4b &b) +inline ColorGeometry4b mix4(const float4 &weights, + const ColorGeometry4b &v0, + const ColorGeometry4b &v1, + const ColorGeometry4b &v2, + const ColorGeometry4b &v3) { - return math::interpolate(a, b, factor); + const float4 v0_f{&v0.r}; + const float4 v1_f{&v1.r}; + const float4 v2_f{&v2.r}; + const float4 v3_f{&v3.r}; + float4 mixed; + interp_v4_v4v4v4v4(mixed, v0_f, v1_f, v2_f, v3_f, weights); + return ColorGeometry4b{static_cast(mixed[0]), + static_cast(mixed[1]), + static_cast(mixed[2]), + static_cast(mixed[3])}; } /** \} */ @@ -188,10 +272,28 @@ template class SimpleMixer { * \param default_value: Output value for an element that has not been affected by a #mix_in. */ SimpleMixer(MutableSpan buffer, T default_value = {}) + : SimpleMixer(buffer, buffer.index_range(), default_value) + { + } + + /** + * \param mask: Only initialize these indices. Other indices in the buffer will be invalid. + */ + SimpleMixer(MutableSpan buffer, const IndexMask mask, T default_value = {}) : buffer_(buffer), default_value_(default_value), total_weights_(buffer.size(), 0.0f) { BLI_STATIC_ASSERT(std::is_trivial_v, ""); - memset(buffer_.data(), 0, sizeof(T) * buffer_.size()); + mask.foreach_index([&](const int64_t i) { buffer_[i] = default_value_; }); + } + + /** + * Set a #value into the element with the given #index. + */ + void set(const int64_t index, const T &value, const float weight = 1.0f) + { + BLI_assert(weight >= 0.0f); + buffer_[index] = value * weight; + total_weights_[index] = weight; } /** @@ -209,7 +311,12 @@ template class SimpleMixer { */ void finalize() { - for (const int64_t i : buffer_.index_range()) { + this->finalize(IndexMask(buffer_.size())); + } + + void finalize(const IndexMask mask) + { + mask.foreach_index([&](const int64_t i) { const float weight = total_weights_[i]; if (weight > 0.0f) { buffer_[i] *= 1.0f / weight; @@ -217,7 +324,7 @@ template class SimpleMixer { else { buffer_[i] = default_value_; } - } + }); } }; @@ -237,9 +344,25 @@ class BooleanPropagationMixer { /** * \param buffer: Span where the interpolated values should be stored. */ - BooleanPropagationMixer(MutableSpan buffer) : buffer_(buffer) + BooleanPropagationMixer(MutableSpan buffer) + : BooleanPropagationMixer(buffer, buffer.index_range()) { - buffer_.fill(false); + } + + /** + * \param mask: Only initialize these indices. Other indices in the buffer will be invalid. + */ + BooleanPropagationMixer(MutableSpan buffer, const IndexMask mask) : buffer_(buffer) + { + mask.foreach_index([&](const int64_t i) { buffer_[i] = false; }); + } + + /** + * Set a #value into the element with the given #index. + */ + void set(const int64_t index, const bool value, [[maybe_unused]] const float weight = 1.0f) + { + buffer_[index] = value; } /** @@ -256,6 +379,10 @@ class BooleanPropagationMixer { void finalize() { } + + void finalize(const IndexMask /*mask*/) + { + } }; /** @@ -277,8 +404,27 @@ class SimpleMixerWithAccumulationType { public: SimpleMixerWithAccumulationType(MutableSpan buffer, T default_value = {}) + : SimpleMixerWithAccumulationType(buffer, buffer.index_range(), default_value) + { + } + + /** + * \param mask: Only initialize these indices. Other indices in the buffer will be invalid. + */ + SimpleMixerWithAccumulationType(MutableSpan buffer, + const IndexMask mask, + T default_value = {}) : buffer_(buffer), default_value_(default_value), accumulation_buffer_(buffer.size()) { + mask.foreach_index([&](const int64_t index) { buffer_[index] = default_value_; }); + } + + void set(const int64_t index, const T &value, const float weight = 1.0f) + { + const AccumulationT converted_value = static_cast(value); + Item &item = accumulation_buffer_[index]; + item.value = converted_value * weight; + item.weight = weight; } void mix_in(const int64_t index, const T &value, const float weight = 1.0f) @@ -291,7 +437,12 @@ class SimpleMixerWithAccumulationType { void finalize() { - for (const int64_t i : buffer_.index_range()) { + this->finalize(buffer_.index_range()); + } + + void finalize(const IndexMask mask) + { + mask.foreach_index([&](const int64_t i) { const Item &item = accumulation_buffer_[i]; if (item.weight > 0.0f) { const float weight_inv = 1.0f / item.weight; @@ -301,7 +452,7 @@ class SimpleMixerWithAccumulationType { else { buffer_[i] = default_value_; } - } + }); } }; @@ -314,8 +465,16 @@ class ColorGeometry4fMixer { public: ColorGeometry4fMixer(MutableSpan buffer, ColorGeometry4f default_color = ColorGeometry4f(0.0f, 0.0f, 0.0f, 1.0f)); + /** + * \param mask: Only initialize these indices. Other indices in the buffer will be invalid. + */ + ColorGeometry4fMixer(MutableSpan buffer, + IndexMask mask, + ColorGeometry4f default_color = ColorGeometry4f(0.0f, 0.0f, 0.0f, 1.0f)); + void set(int64_t index, const ColorGeometry4f &color, float weight = 1.0f); void mix_in(int64_t index, const ColorGeometry4f &color, float weight = 1.0f); void finalize(); + void finalize(IndexMask mask); }; class ColorGeometry4bMixer { @@ -328,8 +487,16 @@ class ColorGeometry4bMixer { public: ColorGeometry4bMixer(MutableSpan buffer, ColorGeometry4b default_color = ColorGeometry4b(0, 0, 0, 255)); + /** + * \param mask: Only initialize these indices. Other indices in the buffer will be invalid. + */ + ColorGeometry4bMixer(MutableSpan buffer, + IndexMask mask, + ColorGeometry4b default_color = ColorGeometry4b(0, 0, 0, 255)); + void set(int64_t index, const ColorGeometry4b &color, float weight = 1.0f); void mix_in(int64_t index, const ColorGeometry4b &color, float weight = 1.0f); void finalize(); + void finalize(IndexMask mask); }; template struct DefaultMixerStruct { @@ -381,12 +548,12 @@ template<> struct DefaultMixerStruct { using type = SimpleMixerWithAccumulationType; }; -template struct DefaultPropatationMixerStruct { +template struct DefaultPropagationMixerStruct { /* Use void by default. This can be checked for in `if constexpr` statements. */ using type = typename DefaultMixerStruct::type; }; -template<> struct DefaultPropatationMixerStruct { +template<> struct DefaultPropagationMixerStruct { using type = BooleanPropagationMixer; }; @@ -396,7 +563,7 @@ template<> struct DefaultPropatationMixerStruct { * (the default mixing for booleans). */ template -using DefaultPropatationMixer = typename DefaultPropatationMixerStruct::type; +using DefaultPropagationMixer = typename DefaultPropagationMixerStruct::type; /* Utility to get a good default mixer for a given type. This is `void` when there is no default * mixer for the given type. */ diff --git a/source/blender/blenkernel/BKE_blender_version.h b/source/blender/blenkernel/BKE_blender_version.h index efe44ec657b..ee9c7a964d9 100644 --- a/source/blender/blenkernel/BKE_blender_version.h +++ b/source/blender/blenkernel/BKE_blender_version.h @@ -17,7 +17,7 @@ extern "C" { */ /* Blender major and minor version. */ -#define BLENDER_VERSION 303 +#define BLENDER_VERSION 304 /* Blender patch version for bugfix releases. */ #define BLENDER_VERSION_PATCH 0 /** Blender release cycle stage: alpha/beta/rc/release. */ @@ -25,7 +25,7 @@ extern "C" { /* Blender file format version. */ #define BLENDER_FILE_VERSION BLENDER_VERSION -#define BLENDER_FILE_SUBVERSION 5 +#define BLENDER_FILE_SUBVERSION 0 /* Minimum Blender version that supports reading file written with the current * version. Older Blender versions will test this and show a warning if the file diff --git a/source/blender/blenkernel/BKE_bpath.h b/source/blender/blenkernel/BKE_bpath.h index ea6049e87da..bc60b6f050e 100644 --- a/source/blender/blenkernel/BKE_bpath.h +++ b/source/blender/blenkernel/BKE_bpath.h @@ -12,6 +12,8 @@ #pragma once +#include "BLI_utildefines.h" + #ifdef __cplusplus extern "C" { #endif @@ -57,6 +59,7 @@ typedef enum eBPathForeachFlag { * \note Only used by Image IDType currently. */ BKE_BPATH_FOREACH_PATH_RELOAD_EDITED = (1 << 9), } eBPathForeachFlag; +ENUM_OPERATORS(eBPathForeachFlag, BKE_BPATH_FOREACH_PATH_RELOAD_EDITED) struct BPathForeachPathData; diff --git a/source/blender/blenkernel/BKE_cachefile.h b/source/blender/blenkernel/BKE_cachefile.h index fd559abf7f2..43ad340103a 100644 --- a/source/blender/blenkernel/BKE_cachefile.h +++ b/source/blender/blenkernel/BKE_cachefile.h @@ -33,7 +33,7 @@ void BKE_cachefile_eval(struct Main *bmain, bool BKE_cachefile_filepath_get(const struct Main *bmain, const struct Depsgraph *depsgrah, const struct CacheFile *cache_file, - char r_filename[1024]); + char r_filepath[1024]); double BKE_cachefile_time_offset(const struct CacheFile *cache_file, double time, double fps); @@ -53,10 +53,12 @@ void BKE_cachefile_reader_free(struct CacheFile *cache_file, struct CacheReader bool BKE_cache_file_uses_render_procedural(const struct CacheFile *cache_file, struct Scene *scene); -/* Add a layer to the cache_file. Return NULL if the filename is already that of an existing layer - * or if the number of layers exceeds the maximum allowed layer count. */ +/** + * Add a layer to the cache_file. Return NULL if the `filepath` is already that of an existing + * layer or if the number of layers exceeds the maximum allowed layer count. + */ struct CacheFileLayer *BKE_cachefile_add_layer(struct CacheFile *cache_file, - const char filename[1024]); + const char filepath[1024]); struct CacheFileLayer *BKE_cachefile_get_active_layer(struct CacheFile *cache_file); diff --git a/source/blender/blenkernel/BKE_cdderivedmesh.h b/source/blender/blenkernel/BKE_cdderivedmesh.h index 3c929857c14..2d1aca7c3c8 100644 --- a/source/blender/blenkernel/BKE_cdderivedmesh.h +++ b/source/blender/blenkernel/BKE_cdderivedmesh.h @@ -25,10 +25,6 @@ struct Mesh; * data to not overwrite the original. */ struct DerivedMesh *CDDM_from_mesh(struct Mesh *mesh); -/* Copies the given DerivedMesh with verts, faces & edges stored as - * custom element data. */ -struct DerivedMesh *CDDM_copy(struct DerivedMesh *source); - #ifdef __cplusplus } #endif diff --git a/source/blender/blenkernel/BKE_cloth.h b/source/blender/blenkernel/BKE_cloth.h index 6af38b14ea4..f5ffd1190b1 100644 --- a/source/blender/blenkernel/BKE_cloth.h +++ b/source/blender/blenkernel/BKE_cloth.h @@ -79,7 +79,7 @@ typedef struct Cloth { int last_frame; float initial_mesh_volume; /* Initial volume of the mesh. Used for pressure */ float average_acceleration[3]; /* Moving average of overall acceleration. */ - struct MEdge *edges; /* Used for hair collisions. */ + const struct MEdge *edges; /* Used for hair collisions. */ struct EdgeSet *sew_edge_graph; /* Sewing edges represented using a GHash */ } Cloth; diff --git a/source/blender/blenkernel/BKE_collection.h b/source/blender/blenkernel/BKE_collection.h index feb3dc7de80..dd7866d83e5 100644 --- a/source/blender/blenkernel/BKE_collection.h +++ b/source/blender/blenkernel/BKE_collection.h @@ -26,6 +26,7 @@ struct BlendExpander; struct BlendLibReader; struct BlendWriter; struct Collection; +struct ID; struct Library; struct Main; struct Object; @@ -94,7 +95,7 @@ struct Collection *BKE_collection_duplicate(struct Main *bmain, /* Master Collection for Scene */ #define BKE_SCENE_COLLECTION_NAME "Scene Collection" -struct Collection *BKE_collection_master_add(void); +struct Collection *BKE_collection_master_add(struct Scene *scene); /* Collection Objects */ @@ -215,7 +216,8 @@ struct ListBase BKE_collection_object_cache_get(struct Collection *collection); ListBase BKE_collection_object_cache_instanced_get(struct Collection *collection); void BKE_collection_object_cache_free(struct Collection *collection); -struct Base *BKE_collection_or_layer_objects(const struct ViewLayer *view_layer, +struct Base *BKE_collection_or_layer_objects(const struct Scene *scene, + struct ViewLayer *view_layer, struct Collection *collection); /* Editing. */ @@ -238,7 +240,8 @@ const char *BKE_collection_ui_name_get(struct Collection *collection); * Select all the objects in this Collection (and its nested collections) for this ViewLayer. * Return true if any object was selected. */ -bool BKE_collection_objects_select(struct ViewLayer *view_layer, +bool BKE_collection_objects_select(const struct Scene *scene, + struct ViewLayer *view_layer, struct Collection *collection, bool deselect); @@ -296,7 +299,9 @@ void BKE_main_collections_parent_relations_rebuild(struct Main *bmain); /* .blend file I/O */ void BKE_collection_blend_write_nolib(struct BlendWriter *writer, struct Collection *collection); -void BKE_collection_blend_read_data(struct BlendDataReader *reader, struct Collection *collection); +void BKE_collection_blend_read_data(struct BlendDataReader *reader, + struct Collection *collection, + struct ID *owner_id); void BKE_collection_blend_read_lib(struct BlendLibReader *reader, struct Collection *collection); void BKE_collection_blend_read_expand(struct BlendExpander *expander, struct Collection *collection); diff --git a/source/blender/blenkernel/BKE_collision.h b/source/blender/blenkernel/BKE_collision.h index b93babaaefa..291d76df4c8 100644 --- a/source/blender/blenkernel/BKE_collision.h +++ b/source/blender/blenkernel/BKE_collision.h @@ -17,6 +17,7 @@ struct Depsgraph; struct MVert; struct MVertTri; struct Object; +struct Scene; //////////////////////////////////////// // used for collisions in collision.c diff --git a/source/blender/blenkernel/BKE_compute_contexts.hh b/source/blender/blenkernel/BKE_compute_contexts.hh new file mode 100644 index 00000000000..a8f0022f49b --- /dev/null +++ b/source/blender/blenkernel/BKE_compute_contexts.hh @@ -0,0 +1,46 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +#pragma once + +/** + * This file implements some specific compute contexts for concepts in Blender. + */ + +#include "BLI_compute_context.hh" + +namespace blender::bke { + +class ModifierComputeContext : public ComputeContext { + private: + static constexpr const char *s_static_type = "MODIFIER"; + + /** + * Use modifier name instead of something like `session_uuid` for now because: + * - It's more obvious that the name matches between the original and evaluated object. + * - We might want that the context hash is consistent between sessions in the future. + */ + std::string modifier_name_; + + public: + ModifierComputeContext(const ComputeContext *parent, std::string modifier_name); + + private: + void print_current_in_line(std::ostream &stream) const override; +}; + +class NodeGroupComputeContext : public ComputeContext { + private: + static constexpr const char *s_static_type = "NODE_GROUP"; + + std::string node_name_; + + public: + NodeGroupComputeContext(const ComputeContext *parent, std::string node_name); + + StringRefNull node_name() const; + + private: + void print_current_in_line(std::ostream &stream) const override; +}; + +} // namespace blender::bke diff --git a/source/blender/blenkernel/BKE_crazyspace.hh b/source/blender/blenkernel/BKE_crazyspace.hh new file mode 100644 index 00000000000..adebf0b7884 --- /dev/null +++ b/source/blender/blenkernel/BKE_crazyspace.hh @@ -0,0 +1,53 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +/** \file + * \ingroup bke + */ + +#pragma once + +#include "BLI_float3x3.hh" +#include "BLI_math_vec_types.hh" +#include "BLI_span.hh" + +struct Depsgraph; +struct Object; + +namespace blender::bke::crazyspace { + +/** + * Contains information about how points have been deformed during evaluation. + * This allows mapping edits on evaluated data back to original data in some cases. + */ +struct GeometryDeformation { + /** + * Positions of the deformed points. This may also point to the original position if no + * deformation data is available. + */ + Span positions; + /** + * Matrices that transform point translations on original data into corresponding translations in + * evaluated data. This may be empty if not available. + */ + Span deform_mats; + + float3 translation_from_deformed_to_original(const int position_i, + const float3 &translation) const + { + if (this->deform_mats.is_empty()) { + return translation; + } + const float3x3 &deform_mat = this->deform_mats[position_i]; + return deform_mat.inverted() * translation; + } +}; + +/** + * During evaluation of the object, deformation data may have been generated for this object. This + * function either retrieves the deformation data from the evaluated object, or falls back to + * returning the original data. + */ +GeometryDeformation get_evaluated_curves_deformation(const Depsgraph &depsgraph, + const Object &ob_orig); + +} // namespace blender::bke::crazyspace diff --git a/source/blender/blenkernel/BKE_cryptomatte.h b/source/blender/blenkernel/BKE_cryptomatte.h index 56049ecf405..b2024f09278 100644 --- a/source/blender/blenkernel/BKE_cryptomatte.h +++ b/source/blender/blenkernel/BKE_cryptomatte.h @@ -25,6 +25,8 @@ struct CryptomatteSession *BKE_cryptomatte_init(void); struct CryptomatteSession *BKE_cryptomatte_init_from_render_result( const struct RenderResult *render_result); struct CryptomatteSession *BKE_cryptomatte_init_from_scene(const struct Scene *scene); +struct CryptomatteSession *BKE_cryptomatte_init_from_view_layer( + const struct ViewLayer *view_layer); void BKE_cryptomatte_free(struct CryptomatteSession *session); void BKE_cryptomatte_add_layer(struct CryptomatteSession *session, const char *layer_name); diff --git a/source/blender/blenkernel/BKE_cryptomatte.hh b/source/blender/blenkernel/BKE_cryptomatte.hh index cd3f8dc9f58..dd08f7b5c4f 100644 --- a/source/blender/blenkernel/BKE_cryptomatte.hh +++ b/source/blender/blenkernel/BKE_cryptomatte.hh @@ -12,6 +12,7 @@ #include "BKE_cryptomatte.h" +#include "BLI_hash_mm3.h" #include "BLI_map.hh" #include "BLI_string_ref.hh" @@ -54,10 +55,14 @@ struct CryptomatteHash { uint32_t hash; CryptomatteHash(uint32_t hash); - CryptomatteHash(const char *name, int name_len); - static CryptomatteHash from_hex_encoded(blender::StringRef hex_encoded); + CryptomatteHash(const char *name, int name_len) + { + hash = BLI_hash_mm3((const unsigned char *)name, name_len, 0); + } + static CryptomatteHash from_hex_encoded(blender::StringRef hex_encoded); std::string hex_encoded() const; + /** * Convert a cryptomatte hash to a float. * @@ -70,7 +75,20 @@ struct CryptomatteHash { * * Note that this conversion assumes to be running on a L-endian system. */ - float float_encoded() const; + float float_encoded() const + { + uint32_t mantissa = hash & ((1 << 23) - 1); + uint32_t exponent = (hash >> 23) & ((1 << 8) - 1); + exponent = MAX2(exponent, (uint32_t)1); + exponent = MIN2(exponent, (uint32_t)254); + exponent = exponent << 23; + uint32_t sign = (hash >> 31); + sign = sign << 31; + uint32_t float_bits = sign | exponent | mantissa; + float f; + memcpy(&f, &float_bits, sizeof(uint32_t)); + return f; + } }; struct CryptomatteLayer { @@ -107,6 +125,8 @@ struct CryptomatteStampDataCallbackData { const blender::Vector &BKE_cryptomatte_layer_names_get( const CryptomatteSession &session); +CryptomatteLayer *BKE_cryptomatte_layer_get(CryptomatteSession &session, + const StringRef layer_name); struct CryptomatteSessionDeleter { void operator()(CryptomatteSession *session) diff --git a/source/blender/blenkernel/BKE_curves.h b/source/blender/blenkernel/BKE_curves.h index c3302c6d2aa..71a0562e1df 100644 --- a/source/blender/blenkernel/BKE_curves.h +++ b/source/blender/blenkernel/BKE_curves.h @@ -25,7 +25,7 @@ void *BKE_curves_add(struct Main *bmain, const char *name); struct BoundBox *BKE_curves_boundbox_get(struct Object *ob); -bool BKE_curves_customdata_required(const struct Curves *curves, const char *name); +bool BKE_curves_attribute_required(const struct Curves *curves, const char *name); /* Depsgraph */ diff --git a/source/blender/blenkernel/BKE_curves.hh b/source/blender/blenkernel/BKE_curves.hh index fb97e52f6da..0d67152dec8 100644 --- a/source/blender/blenkernel/BKE_curves.hh +++ b/source/blender/blenkernel/BKE_curves.hh @@ -11,6 +11,7 @@ #include +#include "BLI_float3x3.hh" #include "BLI_float4x4.hh" #include "BLI_generic_virtual_array.hh" #include "BLI_index_mask.hh" @@ -21,6 +22,7 @@ #include "BLI_virtual_array.hh" #include "BKE_attribute.hh" +#include "BKE_attribute_math.hh" namespace blender::bke { @@ -96,7 +98,7 @@ class CurvesGeometryRuntime { mutable Span evaluated_positions_span; /** - * Cache of lengths along each evaluated curve for for each evaluated point. If a curve is + * Cache of lengths along each evaluated curve for each evaluated point. If a curve is * cyclic, it needs one more length value to correspond to the last segment, so in order to * make slicing this array for a curve fast, an extra float is stored for every curve. */ @@ -149,11 +151,22 @@ class CurvesGeometry : public ::CurvesGeometry { * Accessors. */ + /** + * The total number of control points in all curves. + */ int points_num() const; + /** + * The number of curves in the data-block. + */ int curves_num() const; IndexRange points_range() const; IndexRange curves_range() const; + /** + * Number of control points in the indexed curve. + */ + int points_num_for_curve(const int index) const; + /** * The index of the first point in every curve. The size of this span is one larger than the * number of curves. Consider using #points_for_curve rather than using the offsets directly. @@ -205,7 +218,7 @@ class CurvesGeometry : public ::CurvesGeometry { /** * How many evaluated points to create for each segment when evaluating Bezier, - * Catmull Rom, and NURBS curves. On the curve domain. + * Catmull Rom, and NURBS curves. On the curve domain. Values must be one or greater. */ VArray resolution() const; /** Mutable access to curve resolution. Call #tag_topology_changed after changes. */ @@ -337,12 +350,14 @@ class CurvesGeometry : public ::CurvesGeometry { /** Calculates the data described by #evaluated_lengths_for_curve if necessary. */ void ensure_evaluated_lengths() const; + void ensure_can_interpolate_to_evaluated() const; + /** * Evaluate a generic data to the standard evaluated points of a specific curve, * defined by the resolution attribute or other factors, depending on the curve type. * * \warning This function expects offsets to the evaluated points for each curve to be - * calculated. That can be ensured with #ensure_evaluated_offsets. + * calculated. That can be ensured with #ensure_can_interpolate_to_evaluated. */ void interpolate_to_evaluated(int curve_index, GSpan src, GMutableSpan dst) const; /** @@ -385,8 +400,6 @@ class CurvesGeometry : public ::CurvesGeometry { void calculate_bezier_auto_handles(); - void update_customdata_pointers(); - void remove_points(IndexMask points_to_delete); void remove_curves(IndexMask curves_to_delete); @@ -416,6 +429,38 @@ class CurvesGeometry : public ::CurvesGeometry { } }; +/** + * Used to propagate deformation data through modifier evaluation so that sculpt tools can work on + * evaluated data. + */ +class CurvesEditHints { + public: + /** + * Original data that the edit hints below are meant to be used for. + */ + const Curves &curves_id_orig; + /** + * Evaluated positions for the points in #curves_orig. If this is empty, the positions from the + * evaluated #Curves should be used if possible. + */ + std::optional> positions; + /** + * Matrices which transform point movement vectors from original data to corresponding movements + * of evaluated data. + */ + std::optional> deform_mats; + + CurvesEditHints(const Curves &curves_id_orig) : curves_id_orig(curves_id_orig) + { + } + + /** + * The edit hints have to correspond to the original curves, i.e. the number of deformed points + * is the same as the number of original points. + */ + bool is_valid() const; +}; + namespace curves { /* -------------------------------------------------------------------- */ @@ -492,6 +537,16 @@ bool segment_is_vector(Span handle_types_left, Span handle_types_right, int segment_index); +/** + * True if the Bezier curve contains polygonal segments of HandleType::BEZIER_HANDLE_VECTOR. + * + * \param num_curve_points: Number of points in the curve. + * \param evaluated_size: Number of evaluated points in the curve. + * \param cyclic: If curve is cyclic. + * \param resolution: Curve resolution. + */ +bool has_vector_handles(int num_curve_points, int64_t evaluated_size, bool cyclic, int resolution); + /** * Return true if the curve's last cyclic segment has a vector type. * This only makes a difference in the shape of cyclic curves. @@ -520,7 +575,7 @@ void calculate_evaluated_offsets(Span handle_types_left, int resolution, MutableSpan evaluated_offsets); -/** See #insert. */ +/** Knot insertion result, see #insert. */ struct Insertion { float3 handle_prev; float3 left_handle; @@ -530,8 +585,12 @@ struct Insertion { }; /** - * Compute the Bezier segment insertion for the given parameter on the segment, returning - * the position and handles of the new point and the updated existing handle positions. + * Compute the insertion of a control point and handles in a Bezier segment without changing its + * shape. + * \param parameter: Factor in from 0 to 1 defining the insertion point within the segment. + * \return Inserted point parameters including position, and both new and updated handles for + * neighboring control points. + * * 
  *           handle_prev         handle_next
  *                x-----------------x
@@ -650,6 +709,29 @@ void interpolate_to_evaluated(const GSpan src,
                               const Span evaluated_offsets,
                               GMutableSpan dst);
 
+void calculate_basis(const float parameter, float4 &r_weights);
+
+/**
+ * Interpolate the control point values for the given parameter on the piecewise segment.
+ * \param a: Value associated with the first control point influencing the segment.
+ * \param d: Value associated with the fourth control point.
+ * \param parameter: Parameter in range [0, 1] to compute the interpolation for.
+ */
+template
+T interpolate(const T &a, const T &b, const T &c, const T &d, const float parameter)
+{
+  BLI_assert(0.0f <= parameter && parameter <= 1.0f);
+  float4 n;
+  calculate_basis(parameter, n);
+  if constexpr (is_same_any_v) {
+    /* Save multiplications by adjusting weights after mix. */
+    return 0.5f * attribute_math::mix4(n, a, b, c, d);
+  }
+  else {
+    return attribute_math::mix4(n * 0.5f, a, b, c, d);
+  }
+}
+
 }  // namespace catmull_rom
 
 /** \} */
@@ -735,6 +817,12 @@ Curves *curves_new_nomain(CurvesGeometry curves);
  */
 Curves *curves_new_nomain_single(int points_num, CurveType type);
 
+/**
+ * Copy data from #src to #dst, except the geometry data in #CurvesGeometry. Typically used to
+ * copy high-level parameters when a geometry-altering operation creates a new curves data-block.
+ */
+void curves_copy_parameters(const Curves &src, Curves &dst);
+
 std::array calculate_type_counts(const VArray &types);
 
 /* -------------------------------------------------------------------- */
@@ -758,6 +846,16 @@ inline IndexRange CurvesGeometry::curves_range() const
   return IndexRange(this->curves_num());
 }
 
+inline int CurvesGeometry::points_num_for_curve(const int index) const
+{
+  BLI_assert(this->curve_num > 0);
+  BLI_assert(this->curve_num > index);
+  BLI_assert(this->curve_offsets != nullptr);
+  const int offset = this->curve_offsets[index];
+  const int offset_next = this->curve_offsets[index + 1];
+  return offset_next - offset;
+}
+
 inline bool CurvesGeometry::is_single_type(const CurveType type) const
 {
   return this->curve_type_counts()[type] == this->curves_num();
@@ -784,6 +882,7 @@ inline IndexRange CurvesGeometry::points_for_curve(const int index) const
 {
   /* Offsets are not allocated when there are no curves. */
   BLI_assert(this->curve_num > 0);
+  BLI_assert(this->curve_num > index);
   BLI_assert(this->curve_offsets != nullptr);
   const int offset = this->curve_offsets[index];
   const int offset_next = this->curve_offsets[index + 1];
@@ -856,11 +955,13 @@ inline float CurvesGeometry::evaluated_length_total_for_curve(const int curve_in
 
 /** \} */
 
+namespace curves {
+
 /* -------------------------------------------------------------------- */
 /** \name Bezier Inline Methods
  * \{ */
 
-namespace curves::bezier {
+namespace bezier {
 
 inline bool point_is_sharp(const Span handle_types_left,
                            const Span handle_types_right,
@@ -880,14 +981,24 @@ inline bool segment_is_vector(const int8_t left, const int8_t right)
   return segment_is_vector(HandleType(left), HandleType(right));
 }
 
+inline bool has_vector_handles(const int num_curve_points,
+                               const int64_t evaluated_size,
+                               const bool cyclic,
+                               const int resolution)
+{
+  return evaluated_size - !cyclic != (int64_t)segments_num(num_curve_points, cyclic) * resolution;
+}
+
 inline float3 calculate_vector_handle(const float3 &point, const float3 &next_point)
 {
   return math::interpolate(point, next_point, 1.0f / 3.0f);
 }
 
+}  // namespace bezier
+
 /** \} */
 
-}  // namespace curves::bezier
+}  // namespace curves
 
 struct CurvesSurfaceTransforms {
   float4x4 curves_to_world;
diff --git a/source/blender/blenkernel/BKE_curves_utils.hh b/source/blender/blenkernel/BKE_curves_utils.hh
index f223e173ea9..f9155023db7 100644
--- a/source/blender/blenkernel/BKE_curves_utils.hh
+++ b/source/blender/blenkernel/BKE_curves_utils.hh
@@ -11,9 +11,301 @@
 
 #include "BLI_function_ref.hh"
 #include "BLI_generic_pointer.hh"
+#include "BLI_index_range.hh"
 
 namespace blender::bke::curves {
 
+/* -------------------------------------------------------------------- */
+/** \name Utility Structs
+ * \{ */
+
+/**
+ * Reference to a piecewise segment on a spline curve.
+ */
+struct CurveSegment {
+  /**
+   * Index of the previous control/evaluated point on the curve. First point on the segment.
+   */
+  int index;
+  /**
+   * Index of the next control/evaluated point on the curve. Last point on the curve segment.
+   * Should be 0 for looped segments.
+   */
+  int next_index;
+};
+
+/**
+ * Reference to a point on a piecewise curve (spline).
+ *
+ * Tracks indices of the neighboring control/evaluated point pair associated with the segment
+ * in which the point resides. Referenced point within the segment is defined by a
+ * normalized parameter in the range [0, 1].
+ */
+struct CurvePoint : public CurveSegment {
+  /**
+   * Normalized parameter in the range [0, 1] defining the point on the piecewise segment.
+   * Note that the curve point representation is not unique at segment endpoints.
+   */
+  float parameter;
+
+  /**
+   * True if the parameter is an integer and references a control/evaluated point.
+   */
+  inline bool is_controlpoint() const;
+
+  /*
+   * Compare if the points are equal.
+   */
+  inline bool operator==(const CurvePoint &other) const;
+  inline bool operator!=(const CurvePoint &other) const;
+
+  /**
+   * Compare if 'this' point comes before 'other'. Loop segment for cyclical curves counts
+   * as the first (least) segment.
+   */
+  inline bool operator<(const CurvePoint &other) const;
+};
+
+/**
+ * Cyclical index range. Iterates the interval [start, end).
+ */
+class IndexRangeCyclic {
+  /* Index to the start and end of the iterated range.
+   */
+  int64_t start_ = 0;
+  int64_t end_ = 0;
+  /* Index for the start and end of the entire iterable range which contains the iterated range
+   * (e.g. the point range for an individual spline/curve within the entire Curves point domain).
+   */
+  int64_t range_start_ = 0;
+  int64_t range_end_ = 0;
+  /* Number of times the range end is passed when the range is iterated.
+   */
+  int64_t cycles_ = 0;
+
+  constexpr IndexRangeCyclic(int64_t begin,
+                             int64_t end,
+                             int64_t iterable_range_start,
+                             int64_t iterable_range_end,
+                             int64_t cycles)
+      : start_(begin),
+        end_(end),
+        range_start_(iterable_range_start),
+        range_end_(iterable_range_end),
+        cycles_(cycles)
+  {
+  }
+
+ public:
+  constexpr IndexRangeCyclic() = default;
+  ~IndexRangeCyclic() = default;
+
+  constexpr IndexRangeCyclic(int64_t start, int64_t end, IndexRange iterable_range, int64_t cycles)
+      : start_(start),
+        end_(end),
+        range_start_(iterable_range.first()),
+        range_end_(iterable_range.one_after_last()),
+        cycles_(cycles)
+  {
+  }
+
+  /**
+   * Create an iterator over the cyclical interval [start_index, end_index).
+   */
+  constexpr IndexRangeCyclic(int64_t start, int64_t end, IndexRange iterable_range)
+      : start_(start),
+        end_(end == iterable_range.one_after_last() ? iterable_range.first() : end),
+        range_start_(iterable_range.first()),
+        range_end_(iterable_range.one_after_last()),
+        cycles_(end < start)
+  {
+  }
+
+  /**
+   * Increment the range by adding the given number of indices to the beginning of the range.
+   */
+  constexpr IndexRangeCyclic push_forward(int n)
+  {
+    BLI_assert(n >= 0);
+    int64_t nstart = start_ - n;
+    int64_t cycles = cycles_;
+    if (nstart < range_start_) {
+
+      cycles += (int64_t)(n / (range_end_ - range_start_)) + (end_ < nstart) - (end_ < start_);
+    }
+    return {nstart, end_, range_start_, range_end_, cycles};
+  }
+  /**
+   * Increment the range by adding the given number of indices to the end of the range.
+   */
+  constexpr IndexRangeCyclic push_backward(int n)
+  {
+    BLI_assert(n >= 0);
+    int64_t new_end = end_ + n;
+    int64_t cycles = cycles_;
+    if (range_end_ <= new_end) {
+      cycles += (int64_t)(n / (range_end_ - range_start_)) + (new_end < start_) - (end_ < start_);
+    }
+    return {start_, new_end, range_start_, range_end_, cycles};
+  }
+
+  /**
+   * Get the index range for the curve buffer.
+   */
+  constexpr IndexRange curve_range() const
+  {
+    return IndexRange(range_start_, total_size());
+  }
+
+  /**
+   * Range between the first element up to the end of the range.
+   */
+  constexpr IndexRange range_before_loop() const
+  {
+    return IndexRange(start_, size_before_loop());
+  }
+
+  /**
+   * Range between the first element in the iterable range up to the last element in the range.
+   */
+  constexpr IndexRange range_after_loop() const
+  {
+    return IndexRange(range_start_, size_after_loop());
+  }
+
+  /**
+   * Size of the entire iterable range.
+   */
+  constexpr int64_t total_size() const
+  {
+    return range_end_ - range_start_;
+  }
+
+  /**
+   * Number of elements between the first element in the range up to the last element in the curve.
+   */
+  constexpr int64_t size_before_loop() const
+  {
+    return range_end_ - start_;
+  }
+
+  /**
+   * Number of elements between the first element in the iterable range up to the last element in
+   * the range.
+   */
+  constexpr int64_t size_after_loop() const
+  {
+    return end_ - range_start_;
+  }
+
+  /**
+   * Get number of elements iterated by the cyclical index range.
+   */
+  constexpr int64_t size() const
+  {
+    if (cycles_ > 0) {
+      return size_before_loop() + end_ + (cycles_ - 1) * (range_end_ - range_start_);
+    }
+    else {
+      return end_ - start_;
+    }
+  }
+
+  /**
+   * Return the number of times the iterator will cycle before ending.
+   */
+  constexpr int64_t cycles() const
+  {
+    return cycles_;
+  }
+
+  constexpr int64_t first() const
+  {
+    return start_;
+  }
+
+  constexpr int64_t one_after_last() const
+  {
+    return end_;
+  }
+
+  struct CyclicIterator; /* Forward declaration */
+
+  constexpr CyclicIterator begin() const
+  {
+    return CyclicIterator(range_start_, range_end_, start_, 0);
+  }
+
+  constexpr CyclicIterator end() const
+  {
+    return CyclicIterator(range_start_, range_end_, end_, cycles_);
+  }
+
+  struct CyclicIterator {
+    int64_t index_, begin_, end_, cycles_;
+
+    constexpr CyclicIterator(int64_t range_begin, int64_t range_end, int64_t index, int64_t cycles)
+        : index_(index), begin_(range_begin), end_(range_end), cycles_(cycles)
+    {
+      BLI_assert(range_begin <= index && index <= range_end);
+    }
+
+    constexpr CyclicIterator(const CyclicIterator ©)
+        : index_(copy.index_), begin_(copy.begin_), end_(copy.end_), cycles_(copy.cycles_)
+    {
+    }
+    ~CyclicIterator() = default;
+
+    constexpr CyclicIterator &operator=(const CyclicIterator ©)
+    {
+      if (this == ©) {
+        return *this;
+      }
+      index_ = copy.index_;
+      begin_ = copy.begin_;
+      end_ = copy.end_;
+      cycles_ = copy.cycles_;
+      return *this;
+    }
+    constexpr CyclicIterator &operator++()
+    {
+      index_++;
+      if (index_ == end_) {
+        index_ = begin_;
+        cycles_++;
+      }
+      return *this;
+    }
+
+    void increment(int64_t n)
+    {
+      for (int i = 0; i < n; i++) {
+        ++*this;
+      }
+    }
+
+    constexpr const int64_t &operator*() const
+    {
+      return index_;
+    }
+
+    constexpr bool operator==(const CyclicIterator &other) const
+    {
+      return index_ == other.index_ && cycles_ == other.cycles_;
+    }
+    constexpr bool operator!=(const CyclicIterator &other) const
+    {
+      return !this->operator==(other);
+    }
+  };
+};
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Utility Functions
+ * \{ */
+
 /**
  * Copy the provided point attribute values between all curves in the #curve_ranges index
  * ranges, assuming that all curves have the same number of control points in #src_curves
@@ -34,8 +326,8 @@ void copy_point_data(const CurvesGeometry &src_curves,
 template
 void copy_point_data(const CurvesGeometry &src_curves,
                      const CurvesGeometry &dst_curves,
-                     const IndexMask src_curve_selection,
-                     const Span src,
+                     IndexMask src_curve_selection,
+                     Span src,
                      MutableSpan dst)
 {
   copy_point_data(src_curves, dst_curves, src_curve_selection, GSpan(src), GMutableSpan(dst));
@@ -48,13 +340,34 @@ void fill_points(const CurvesGeometry &curves,
 
 template
 void fill_points(const CurvesGeometry &curves,
-                 const IndexMask curve_selection,
+                 IndexMask curve_selection,
                  const T &value,
                  MutableSpan dst)
 {
   fill_points(curves, curve_selection, &value, dst);
 }
 
+void fill_points(const CurvesGeometry &curves,
+                 Span curve_ranges,
+                 GPointer value,
+                 GMutableSpan dst);
+
+template
+void fill_points(const CurvesGeometry &curves,
+                 Span curve_ranges,
+                 const T &value,
+                 MutableSpan dst)
+{
+  fill_points(curves, curve_ranges, &value, dst);
+}
+
+/**
+ * Copy only the information on the point domain, but not the offsets or any point attributes,
+ * meant for operations that change the number of points but not the number of curves.
+ * \warning The returned curves have invalid offsets!
+ */
+bke::CurvesGeometry copy_only_curve_domain(const bke::CurvesGeometry &src_curves);
+
 /**
  * Copy the size of every curve in #curve_ranges to the corresponding index in #counts.
  */
@@ -81,4 +394,40 @@ void foreach_curve_by_type(const VArray &types,
                            FunctionRef bezier_fn,
                            FunctionRef nurbs_fn);
 
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name #CurvePoint Inline Methods
+ * \{ */
+
+inline bool CurvePoint::is_controlpoint() const
+{
+  return parameter == 0.0 || parameter == 1.0;
+}
+
+inline bool CurvePoint::operator==(const CurvePoint &other) const
+{
+  return (parameter == other.parameter && index == other.index) ||
+         (parameter == 1.0 && other.parameter == 0.0 && next_index == other.index) ||
+         (parameter == 0.0 && other.parameter == 1.0 && index == other.next_index);
+}
+inline bool CurvePoint::operator!=(const CurvePoint &other) const
+{
+  return !this->operator==(other);
+}
+
+inline bool CurvePoint::operator<(const CurvePoint &other) const
+{
+  if (index == other.index) {
+    return parameter < other.parameter;
+  }
+  else {
+    /* Use next index for cyclic comparison due to loop segment < first segment. */
+    return next_index < other.next_index &&
+           !(next_index == other.index && parameter == 1.0 && other.parameter == 0.0);
+  }
+}
+
+/** \} */
+
 }  // namespace blender::bke::curves
diff --git a/source/blender/blenkernel/BKE_customdata.h b/source/blender/blenkernel/BKE_customdata.h
index 010fbb27172..064eb9ca1ed 100644
--- a/source/blender/blenkernel/BKE_customdata.h
+++ b/source/blender/blenkernel/BKE_customdata.h
@@ -11,7 +11,9 @@
 #include "BLI_sys_types.h"
 #include "BLI_utildefines.h"
 #ifdef __cplusplus
+#  include "BLI_set.hh"
 #  include "BLI_span.hh"
+#  include "BLI_string_ref.hh"
 #  include "BLI_vector.hh"
 #endif
 
@@ -53,14 +55,17 @@ extern const CustomData_MeshMasks CD_MASK_EVERYTHING;
 typedef enum eCDAllocType {
   /** Use the data pointer. */
   CD_ASSIGN = 0,
-  /** Allocate blank memory. */
-  CD_CALLOC = 1,
-  /** Allocate and set to default. */
-  CD_DEFAULT = 2,
+  /** Allocate and set to default, which is usually just zeroed memory. */
+  CD_SET_DEFAULT = 2,
   /** Use data pointers, set layer flag NOFREE. */
   CD_REFERENCE = 3,
   /** Do a full copy of all layers, only allowed if source has same number of elements. */
   CD_DUPLICATE = 4,
+  /**
+   * Default construct new layer values. Does nothing for trivial types. This should be used
+   * if all layer values will be set by the caller after creating the layer.
+   */
+  CD_CONSTRUCT = 5,
 } eCDAllocType;
 
 #define CD_TYPE_AS_MASK(_type) (eCustomDataMask)((eCustomDataMask)1 << (eCustomDataMask)(_type))
@@ -132,7 +137,7 @@ void CustomData_data_add(int type, void *data1, const void *data2);
 
 /**
  * Initializes a CustomData object with the same layer setup as source.
- * mask is a bitfield where `(mask & (1 << (layer type)))` indicates
+ * mask is a bit-field where `(mask & (1 << (layer type)))` indicates
  * if a layer should be copied or not. alloctype must be one of the above.
  */
 void CustomData_copy(const struct CustomData *source,
@@ -141,6 +146,15 @@ void CustomData_copy(const struct CustomData *source,
                      eCDAllocType alloctype,
                      int totelem);
 
+/**
+ * Like #CustomData_copy but skips copying layers that are stored as flags on #BMesh.
+ */
+void CustomData_copy_mesh_to_bmesh(const struct CustomData *source,
+                                   struct CustomData *dest,
+                                   eCustomDataMask mask,
+                                   eCDAllocType alloctype,
+                                   int totelem);
+
 /* BMESH_TODO, not really a public function but readfile.c needs it */
 void CustomData_update_typemap(struct CustomData *data);
 
@@ -155,13 +169,20 @@ bool CustomData_merge(const struct CustomData *source,
                       int totelem);
 
 /**
- * Reallocate custom data to a new element count.
- * Only affects on data layers which are owned by the CustomData itself,
- * referenced data is kept unchanged,
- *
- * \note Take care of referenced layers by yourself!
+ * Like #CustomData_copy but skips copying layers that are stored as flags on #BMesh.
+ */
+bool CustomData_merge_mesh_to_bmesh(const struct CustomData *source,
+                                    struct CustomData *dest,
+                                    eCustomDataMask mask,
+                                    eCDAllocType alloctype,
+                                    int totelem);
+
+/**
+ * Reallocate custom data to a new element count. If the new size is larger, the new values use
+ * the #CD_CONSTRUCT behavior, so trivial types must be initialized by the caller. After being
+ * resized, the #CustomData does not contain any referenced layers.
  */
-void CustomData_realloc(struct CustomData *data, int totelem);
+void CustomData_realloc(struct CustomData *data, int old_size, int new_size);
 
 /**
  * BMesh version of CustomData_merge; merges the layouts of source and `dest`,
@@ -397,7 +418,7 @@ void *CustomData_bmesh_get_n(const struct CustomData *data, void *block, int typ
  */
 void *CustomData_bmesh_get_layer_n(const struct CustomData *data, void *block, int n);
 
-bool CustomData_set_layer_name(const struct CustomData *data, int type, int n, const char *name);
+bool CustomData_set_layer_name(struct CustomData *data, int type, int n, const char *name);
 const char *CustomData_get_layer_name(const struct CustomData *data, int type, int n);
 
 /**
@@ -408,6 +429,7 @@ void *CustomData_get_layer(const struct CustomData *data, int type);
 void *CustomData_get_layer_n(const struct CustomData *data, int type, int n);
 void *CustomData_get_layer_named(const struct CustomData *data, int type, const char *name);
 int CustomData_get_offset(const struct CustomData *data, int type);
+int CustomData_get_offset_named(const CustomData *data, int type, const char *name);
 int CustomData_get_n_offset(const struct CustomData *data, int type, int n);
 
 int CustomData_get_layer_index(const struct CustomData *data, int type);
@@ -429,6 +451,12 @@ int CustomData_get_stencil_layer(const struct CustomData *data, int type);
  */
 const char *CustomData_get_active_layer_name(const struct CustomData *data, int type);
 
+/**
+ * Returns name of the default layer of the given type or NULL
+ * if no such active layer is defined.
+ */
+const char *CustomData_get_render_layer_name(const struct CustomData *data, int type);
+
 /**
  * Copies the data from source to the data element at index in the first layer of type
  * no effect if there is no layer of type.
@@ -610,7 +638,6 @@ enum {
   CD_FAKE_CREASE = CD_FAKE | CD_CREASE, /* *sigh*. */
 
   /* Multiple types of mesh elements... */
-  CD_FAKE_BWEIGHT = CD_FAKE | CD_BWEIGHT, /* *sigh*. */
   CD_FAKE_UV = CD_FAKE |
                CD_MLOOPUV, /* UV flag, because we handle both loop's UVs and poly's textures. */
 
@@ -666,7 +693,7 @@ typedef struct CustomDataTransferLayerMap {
   size_t data_size;
   /** Offset of actual data we transfer (in element contained in data_src/dst). */
   size_t data_offset;
-  /** For bitflag transfer, flag(s) to affect in transferred data. */
+  /** For bit-flag transfer, flag(s) to affect in transferred data. */
   uint64_t data_flag;
 
   /** Opaque pointer, to be used by specific interp callback (e.g. transformspace for normals). */
@@ -696,7 +723,8 @@ void CustomData_data_transfer(const struct MeshPairRemap *me_remap,
  * the struct.
  */
 void CustomData_blend_write_prepare(CustomData &data,
-                                    blender::Vector &layers_to_write);
+                                    blender::Vector &layers_to_write,
+                                    const blender::Set &skip_names = {});
 
 /**
  * \param layers_to_write: Layers created by #CustomData_blend_write_prepare.
@@ -712,6 +740,8 @@ void CustomData_blend_write(BlendWriter *writer,
 
 void CustomData_blend_read(struct BlendDataReader *reader, struct CustomData *data, int count);
 
+size_t CustomData_get_elem_size(struct CustomDataLayer *layer);
+
 #ifndef NDEBUG
 struct DynStr;
 /** Use to inspect mesh data when debugging. */
diff --git a/source/blender/blenkernel/BKE_deform.h b/source/blender/blenkernel/BKE_deform.h
index a21d9141ac0..4023d6829d4 100644
--- a/source/blender/blenkernel/BKE_deform.h
+++ b/source/blender/blenkernel/BKE_deform.h
@@ -50,16 +50,34 @@ void BKE_defgroup_copy_list(struct ListBase *outbase, const struct ListBase *inb
 struct bDeformGroup *BKE_defgroup_duplicate(const struct bDeformGroup *ingroup);
 struct bDeformGroup *BKE_object_defgroup_find_name(const struct Object *ob, const char *name);
 /**
- * \note caller must free.
+ * Returns flip map for the vertex-groups of `ob`.
+ *
+ * \param use_default: How to handle cases where no symmetrical group is found.
+ * - false: sets these indices to -1, indicating the group should be ignored.
+ * - true: sets the index to its location in the array (making the group point to it's self).
+ *   Enable this for symmetrical actions which apply weight operations on symmetrical vertices
+ *   where the symmetrical group will be used (if found), otherwise the same group is used.
+ *
+ * \return An index array `r_flip_map_num` length,
+ * (aligned with the list result from `BKE_id_defgroup_list_get(ob)`).
+ * referencing the index of the symmetrical vertex-group of a fall-back value (see `use_default`).
+ * The caller is responsible for freeing the array.
+ */
+int *BKE_object_defgroup_flip_map(const struct Object *ob, bool use_default, int *r_flip_map_num);
+
+/**
+ * A version of #BKE_object_defgroup_flip_map that ignores locked groups.
  */
-int *BKE_object_defgroup_flip_map(const struct Object *ob, int *flip_map_len, bool use_default);
+int *BKE_object_defgroup_flip_map_unlocked(const struct Object *ob,
+                                           bool use_default,
+                                           int *r_flip_map_num);
 /**
- * \note caller must free.
+ * A version of #BKE_object_defgroup_flip_map that only takes a single group into account.
  */
 int *BKE_object_defgroup_flip_map_single(const struct Object *ob,
-                                         int *flip_map_len,
                                          bool use_default,
-                                         int defgroup);
+                                         int defgroup,
+                                         int *r_flip_map_num);
 int BKE_object_defgroup_flip_index(const struct Object *ob, int index, bool use_default);
 int BKE_object_defgroup_name_index(const struct Object *ob, const char *name);
 void BKE_object_defgroup_unique_name(struct bDeformGroup *dg, struct Object *ob);
@@ -112,7 +130,7 @@ float BKE_defvert_array_find_weight_safe(const struct MDeformVert *dvert, int in
  * \return The total weight in all groups marked in the selection mask.
  */
 float BKE_defvert_total_selected_weight(const struct MDeformVert *dv,
-                                        int defbase_tot,
+                                        int defbase_num,
                                         const bool *defbase_sel);
 
 /**
@@ -124,9 +142,9 @@ float BKE_defvert_total_selected_weight(const struct MDeformVert *dv,
  * commutative with the collective weight function.
  */
 float BKE_defvert_multipaint_collective_weight(const struct MDeformVert *dv,
-                                               int defbase_tot,
+                                               int defbase_num,
                                                const bool *defbase_sel,
-                                               int defbase_tot_sel,
+                                               int defbase_sel_num,
                                                bool is_normalized);
 
 /* This much unlocked weight is considered equivalent to none. */
@@ -147,7 +165,7 @@ float BKE_defvert_calc_lock_relative_weight(float weight,
  */
 float BKE_defvert_lock_relative_weight(float weight,
                                        const struct MDeformVert *dv,
-                                       int defbase_tot,
+                                       int defbase_num,
                                        const bool *defbase_locked,
                                        const bool *defbase_unlocked);
 
@@ -160,7 +178,7 @@ void BKE_defvert_copy(struct MDeformVert *dvert_dst, const struct MDeformVert *d
 void BKE_defvert_copy_subset(struct MDeformVert *dvert_dst,
                              const struct MDeformVert *dvert_src,
                              const bool *vgroup_subset,
-                             int vgroup_tot);
+                             int vgroup_num);
 /**
  * Overwrite weights filtered by vgroup_subset and with mirroring specified by the flip map
  * - do nothing if neither are set.
@@ -169,9 +187,9 @@ void BKE_defvert_copy_subset(struct MDeformVert *dvert_dst,
 void BKE_defvert_mirror_subset(struct MDeformVert *dvert_dst,
                                const struct MDeformVert *dvert_src,
                                const bool *vgroup_subset,
-                               int vgroup_tot,
+                               int vgroup_num,
                                const int *flip_map,
-                               int flip_map_len);
+                               int flip_map_num);
 /**
  * Copy an index from one #MDeformVert to another.
  * - do nothing if neither are set.
@@ -194,43 +212,43 @@ void BKE_defvert_sync(struct MDeformVert *dvert_dst,
 void BKE_defvert_sync_mapped(struct MDeformVert *dvert_dst,
                              const struct MDeformVert *dvert_src,
                              const int *flip_map,
-                             int flip_map_len,
+                             int flip_map_num,
                              bool use_ensure);
 /**
  * be sure all flip_map values are valid
  */
 void BKE_defvert_remap(struct MDeformVert *dvert, const int *map, int map_len);
-void BKE_defvert_flip(struct MDeformVert *dvert, const int *flip_map, int flip_map_len);
-void BKE_defvert_flip_merged(struct MDeformVert *dvert, const int *flip_map, int flip_map_len);
+void BKE_defvert_flip(struct MDeformVert *dvert, const int *flip_map, int flip_map_num);
+void BKE_defvert_flip_merged(struct MDeformVert *dvert, const int *flip_map, int flip_map_num);
 void BKE_defvert_normalize(struct MDeformVert *dvert);
 /**
  * Same as #BKE_defvert_normalize but takes a bool array.
  */
 void BKE_defvert_normalize_subset(struct MDeformVert *dvert,
                                   const bool *vgroup_subset,
-                                  int vgroup_tot);
+                                  int vgroup_num);
 /**
  * Same as BKE_defvert_normalize() if the locked vgroup is not a member of the subset
  */
 void BKE_defvert_normalize_lock_single(struct MDeformVert *dvert,
                                        const bool *vgroup_subset,
-                                       int vgroup_tot,
+                                       int vgroup_num,
                                        uint def_nr_lock);
 /**
  * Same as BKE_defvert_normalize() if no locked vgroup is a member of the subset
  */
 void BKE_defvert_normalize_lock_map(struct MDeformVert *dvert,
                                     const bool *vgroup_subset,
-                                    int vgroup_tot,
+                                    int vgroup_num,
                                     const bool *lock_flags,
-                                    int defbase_tot);
+                                    int defbase_num);
 
 /* Utilities to 'extract' a given vgroup into a simple float array,
  * for verts, but also edges/polys/loops. */
 
 void BKE_defvert_extract_vgroup_to_vertweights(const struct MDeformVert *dvert,
                                                int defgroup,
-                                               int num_verts,
+                                               int verts_num,
                                                bool invert_vgroup,
                                                float *r_weights);
 /**
@@ -239,25 +257,25 @@ void BKE_defvert_extract_vgroup_to_vertweights(const struct MDeformVert *dvert,
  */
 void BKE_defvert_extract_vgroup_to_edgeweights(const struct MDeformVert *dvert,
                                                int defgroup,
-                                               int num_verts,
-                                               struct MEdge *edges,
-                                               int num_edges,
+                                               int verts_num,
+                                               const struct MEdge *edges,
+                                               int edges_num,
                                                bool invert_vgroup,
                                                float *r_weights);
 void BKE_defvert_extract_vgroup_to_loopweights(const struct MDeformVert *dvert,
                                                int defgroup,
-                                               int num_verts,
-                                               struct MLoop *loops,
-                                               int num_loops,
+                                               int verts_num,
+                                               const struct MLoop *loops,
+                                               int loops_num,
                                                bool invert_vgroup,
                                                float *r_weights);
 void BKE_defvert_extract_vgroup_to_polyweights(const struct MDeformVert *dvert,
                                                int defgroup,
-                                               int num_verts,
-                                               struct MLoop *loops,
-                                               int num_loops,
-                                               struct MPoly *polys,
-                                               int num_polys,
+                                               int verts_num,
+                                               const struct MLoop *loops,
+                                               int loops_num,
+                                               const struct MPoly *polys,
+                                               int polys_num,
                                                bool invert_vgroup,
                                                float *r_weights);
 
diff --git a/source/blender/blenkernel/BKE_displist.h b/source/blender/blenkernel/BKE_displist.h
index 7a21e85e310..6551e732300 100644
--- a/source/blender/blenkernel/BKE_displist.h
+++ b/source/blender/blenkernel/BKE_displist.h
@@ -24,8 +24,6 @@ enum {
   DL_SURF = 2,
   /** Triangles. */
   DL_INDEX3 = 4,
-  /** Quads, with support for triangles (when values of the 3rd and 4th indices match). */
-  DL_INDEX4 = 5,
   // DL_VERTCOL = 6, /* UNUSED */
   /** Isolated points. */
   DL_VERTS = 7,
@@ -61,17 +59,13 @@ typedef struct DispList {
   int totindex; /* indexed array drawing surfaces */
 } DispList;
 
-void BKE_displist_copy(struct ListBase *lbn, const struct ListBase *lb);
 DispList *BKE_displist_find(struct ListBase *lb, int type);
-void BKE_displist_normals_add(struct ListBase *lb);
-void BKE_displist_count(const struct ListBase *lb, int *totvert, int *totface, int *tottri);
 void BKE_displist_free(struct ListBase *lb);
 
 void BKE_displist_make_curveTypes(struct Depsgraph *depsgraph,
                                   const struct Scene *scene,
                                   struct Object *ob,
                                   bool for_render);
-void BKE_displist_make_mball(struct Depsgraph *depsgraph, struct Scene *scene, struct Object *ob);
 
 void BKE_curve_calc_modifiers_pre(struct Depsgraph *depsgraph,
                                   const struct Scene *scene,
diff --git a/source/blender/blenkernel/BKE_effect.h b/source/blender/blenkernel/BKE_effect.h
index 113f9ac3b4c..3226455a183 100644
--- a/source/blender/blenkernel/BKE_effect.h
+++ b/source/blender/blenkernel/BKE_effect.h
@@ -103,6 +103,7 @@ void BKE_partdeflect_free(struct PartDeflect *pd);
  * lookup of effectors during evaluation.
  */
 struct ListBase *BKE_effector_relations_create(struct Depsgraph *depsgraph,
+                                               const struct Scene *scene,
                                                struct ViewLayer *view_layer,
                                                struct Collection *collection);
 void BKE_effector_relations_free(struct ListBase *lb);
diff --git a/source/blender/blenkernel/BKE_fcurve.h b/source/blender/blenkernel/BKE_fcurve.h
index 10d9ce3364d..c11e6353bc0 100644
--- a/source/blender/blenkernel/BKE_fcurve.h
+++ b/source/blender/blenkernel/BKE_fcurve.h
@@ -106,7 +106,7 @@ typedef enum eFMI_Action_Types {
 
 /* Flags for the requirements of a FModifier Type */
 typedef enum eFMI_Requirement_Flags {
-  /* modifier requires original data-points (kindof beats the purpose of a modifier stack?) */
+  /* modifier requires original data-points (kind of beats the purpose of a modifier stack?) */
   FMI_REQUIRES_ORIGINAL_DATA = (1 << 0),
   /* modifier doesn't require on any preceding data (i.e. it will generate a curve).
    * Use in conjunction with FMI_TYPE_GENRATE_CURVE
@@ -463,23 +463,39 @@ bool BKE_fcurve_bezt_subdivide_handles(struct BezTriple *bezt,
                                        struct BezTriple *next,
                                        float *r_pdelta);
 
+/**
+ * Delete a keyframe from an F-curve at a specific index.
+ */
+void BKE_fcurve_delete_key(struct FCurve *fcu, int index);
+
+/**
+ * Delete selected keyframes from an F-curve.
+ */
+bool BKE_fcurve_delete_keys_selected(struct FCurve *fcu);
+
+/**
+ * Delete all keyframes from an F-curve.
+ */
+void BKE_fcurve_delete_keys_all(struct FCurve *fcu);
+
 /* -------- Curve Sanity -------- */
 
 /**
  * This function recalculates the handles of an F-Curve. Acts based on selection with `SELECT`
- * flag. To use a different flag, use #calchandles_fcurve_ex().
+ * flag. To use a different flag, use #BKE_fcurve_handles_recalc_ex().
  *
  * If the BezTriples have been rearranged, sort them first before using this.
  */
-void calchandles_fcurve(struct FCurve *fcu);
+void BKE_fcurve_handles_recalc(struct FCurve *fcu);
 /**
- * Variant of #calchandles_fcurve() that allows calculating based on a different select flag.
+ * Variant of #BKE_fcurve_handles_recalc() that allows calculating based on a different select
+ * flag.
  *
  * \param handle_sel_flag: The flag (bezt.f1/2/3) value to use to determine selection.
  * Usually `SELECT`, but may want to use a different one at times
  * (if caller does not operate on selection).
  */
-void calchandles_fcurve_ex(struct FCurve *fcu, eBezTriple_Flag handle_sel_flag);
+void BKE_fcurve_handles_recalc_ex(struct FCurve *fcu, eBezTriple_Flag handle_sel_flag);
 /**
  * Update handles, making sure the handle-types are valid (e.g. correctly deduced from an "Auto"
  * type), and recalculating their position vectors.
diff --git a/source/blender/blenkernel/BKE_fcurve_driver.h b/source/blender/blenkernel/BKE_fcurve_driver.h
index b6b1bdab109..a1b97222019 100644
--- a/source/blender/blenkernel/BKE_fcurve_driver.h
+++ b/source/blender/blenkernel/BKE_fcurve_driver.h
@@ -85,7 +85,6 @@ void driver_free_variable_ex(struct ChannelDriver *driver, struct DriverVar *dva
 void driver_change_variable_type(struct DriverVar *dvar, int type);
 /**
  * Validate driver variable name (after being renamed).
- *
  */
 void driver_variable_name_validate(struct DriverVar *dvar);
 /**
diff --git a/source/blender/blenkernel/BKE_geometry_fields.hh b/source/blender/blenkernel/BKE_geometry_fields.hh
index 7c504826044..62aac5a4120 100644
--- a/source/blender/blenkernel/BKE_geometry_fields.hh
+++ b/source/blender/blenkernel/BKE_geometry_fields.hh
@@ -8,47 +8,186 @@
  * Common field utilities and field definitions for geometry components.
  */
 
+#include "BKE_attribute.h"
 #include "BKE_geometry_set.hh"
 
 #include "FN_field.hh"
 
+struct Mesh;
+struct PointCloud;
+
 namespace blender::bke {
 
-class GeometryComponentFieldContext : public fn::FieldContext {
+class CurvesGeometry;
+class GeometryFieldInput;
+
+class MeshFieldContext : public fn::FieldContext {
+ private:
+  const Mesh &mesh_;
+  const eAttrDomain domain_;
+
+ public:
+  MeshFieldContext(const Mesh &mesh, const eAttrDomain domain);
+  const Mesh &mesh() const
+  {
+    return mesh_;
+  }
+
+  eAttrDomain domain() const
+  {
+    return domain_;
+  }
+};
+
+class CurvesFieldContext : public fn::FieldContext {
+ private:
+  const CurvesGeometry &curves_;
+  const eAttrDomain domain_;
+
+ public:
+  CurvesFieldContext(const CurvesGeometry &curves, const eAttrDomain domain);
+
+  const CurvesGeometry &curves() const
+  {
+    return curves_;
+  }
+
+  eAttrDomain domain() const
+  {
+    return domain_;
+  }
+};
+
+class PointCloudFieldContext : public fn::FieldContext {
+ private:
+  const PointCloud &pointcloud_;
+
+ public:
+  PointCloudFieldContext(const PointCloud &pointcloud) : pointcloud_(pointcloud)
+  {
+  }
+
+  const PointCloud &pointcloud() const
+  {
+    return pointcloud_;
+  }
+};
+
+class InstancesFieldContext : public fn::FieldContext {
+ private:
+  const InstancesComponent &instances_;
+
+ public:
+  InstancesFieldContext(const InstancesComponent &instances) : instances_(instances)
+  {
+  }
+
+  const InstancesComponent &instances() const
+  {
+    return instances_;
+  }
+};
+
+/**
+ * A field context that can represent meshes, curves, point clouds, or instances,
+ * used for field inputs that can work for multiple geometry types.
+ */
+class GeometryFieldContext : public fn::FieldContext {
  private:
-  const GeometryComponent &component_;
+  /**
+   * Store the geometry as a void pointer instead of a #GeometryComponent to allow referencing data
+   * that doesn't correspond directly to a geometry component type, in this case #CurvesGeometry
+   * instead of #Curves.
+   */
+  const void *geometry_;
+  const GeometryComponentType type_;
   const eAttrDomain domain_;
 
+  friend GeometryFieldInput;
+
  public:
-  GeometryComponentFieldContext(const GeometryComponent &component, const eAttrDomain domain)
-      : component_(component), domain_(domain)
+  GeometryFieldContext(const GeometryComponent &component, eAttrDomain domain);
+  GeometryFieldContext(const void *geometry, GeometryComponentType type, eAttrDomain domain);
+
+  const void *geometry() const
   {
+    return geometry_;
   }
 
-  const GeometryComponent &geometry_component() const
+  GeometryComponentType type() const
   {
-    return component_;
+    return type_;
   }
 
   eAttrDomain domain() const
   {
     return domain_;
   }
+
+  std::optional attributes() const;
+  const Mesh *mesh() const;
+  const CurvesGeometry *curves() const;
+  const PointCloud *pointcloud() const;
+  const InstancesComponent *instances() const;
+
+ private:
+  GeometryFieldContext(const Mesh &mesh, eAttrDomain domain);
+  GeometryFieldContext(const CurvesGeometry &curves, eAttrDomain domain);
+  GeometryFieldContext(const PointCloud &points);
+  GeometryFieldContext(const InstancesComponent &instances);
 };
 
 class GeometryFieldInput : public fn::FieldInput {
  public:
   using fn::FieldInput::FieldInput;
+  GVArray get_varray_for_context(const fn::FieldContext &context,
+                                 IndexMask mask,
+                                 ResourceScope &scope) const override;
+  virtual GVArray get_varray_for_context(const GeometryFieldContext &context,
+                                         IndexMask mask) const = 0;
+};
 
+class MeshFieldInput : public fn::FieldInput {
+ public:
+  using fn::FieldInput::FieldInput;
   GVArray get_varray_for_context(const fn::FieldContext &context,
                                  IndexMask mask,
                                  ResourceScope &scope) const override;
+  virtual GVArray get_varray_for_context(const Mesh &mesh,
+                                         eAttrDomain domain,
+                                         IndexMask mask) const = 0;
+};
 
-  virtual GVArray get_varray_for_context(const GeometryComponent &component,
+class CurvesFieldInput : public fn::FieldInput {
+ public:
+  using fn::FieldInput::FieldInput;
+  GVArray get_varray_for_context(const fn::FieldContext &context,
+                                 IndexMask mask,
+                                 ResourceScope &scope) const override;
+  virtual GVArray get_varray_for_context(const CurvesGeometry &curves,
                                          eAttrDomain domain,
                                          IndexMask mask) const = 0;
 };
 
+class PointCloudFieldInput : public fn::FieldInput {
+ public:
+  using fn::FieldInput::FieldInput;
+  GVArray get_varray_for_context(const fn::FieldContext &context,
+                                 IndexMask mask,
+                                 ResourceScope &scope) const override;
+  virtual GVArray get_varray_for_context(const PointCloud &pointcloud, IndexMask mask) const = 0;
+};
+
+class InstancesFieldInput : public fn::FieldInput {
+ public:
+  using fn::FieldInput::FieldInput;
+  GVArray get_varray_for_context(const fn::FieldContext &context,
+                                 IndexMask mask,
+                                 ResourceScope &scope) const override;
+  virtual GVArray get_varray_for_context(const InstancesComponent &instances,
+                                         IndexMask mask) const = 0;
+};
+
 class AttributeFieldInput : public GeometryFieldInput {
  private:
   std::string name_;
@@ -72,8 +211,7 @@ class AttributeFieldInput : public GeometryFieldInput {
     return name_;
   }
 
-  GVArray get_varray_for_context(const GeometryComponent &component,
-                                 eAttrDomain domain,
+  GVArray get_varray_for_context(const GeometryFieldContext &context,
                                  IndexMask mask) const override;
 
   std::string socket_inspection_name() const override;
@@ -89,8 +227,7 @@ class IDAttributeFieldInput : public GeometryFieldInput {
     category_ = Category::Generated;
   }
 
-  GVArray get_varray_for_context(const GeometryComponent &component,
-                                 eAttrDomain domain,
+  GVArray get_varray_for_context(const GeometryFieldContext &context,
                                  IndexMask mask) const override;
 
   std::string socket_inspection_name() const override;
@@ -99,12 +236,9 @@ class IDAttributeFieldInput : public GeometryFieldInput {
   bool is_equal_to(const fn::FieldNode &other) const override;
 };
 
-VArray curve_normals_varray(const CurveComponent &component, const eAttrDomain domain);
+VArray curve_normals_varray(const CurvesGeometry &curves, const eAttrDomain domain);
 
-VArray mesh_normals_varray(const MeshComponent &mesh_component,
-                                   const Mesh &mesh,
-                                   const IndexMask mask,
-                                   eAttrDomain domain);
+VArray mesh_normals_varray(const Mesh &mesh, const IndexMask mask, eAttrDomain domain);
 
 class NormalFieldInput : public GeometryFieldInput {
  public:
@@ -113,8 +247,7 @@ class NormalFieldInput : public GeometryFieldInput {
     category_ = Category::Generated;
   }
 
-  GVArray get_varray_for_context(const GeometryComponent &component,
-                                 const eAttrDomain domain,
+  GVArray get_varray_for_context(const GeometryFieldContext &context,
                                  IndexMask mask) const override;
 
   std::string socket_inspection_name() const override;
@@ -152,8 +285,7 @@ class AnonymousAttributeFieldInput : public GeometryFieldInput {
     return fn::Field{field_input};
   }
 
-  GVArray get_varray_for_context(const GeometryComponent &component,
-                                 eAttrDomain domain,
+  GVArray get_varray_for_context(const GeometryFieldContext &context,
                                  IndexMask mask) const override;
 
   std::string socket_inspection_name() const override;
@@ -162,10 +294,10 @@ class AnonymousAttributeFieldInput : public GeometryFieldInput {
   bool is_equal_to(const fn::FieldNode &other) const override;
 };
 
-class CurveLengthFieldInput final : public GeometryFieldInput {
+class CurveLengthFieldInput final : public CurvesFieldInput {
  public:
   CurveLengthFieldInput();
-  GVArray get_varray_for_context(const GeometryComponent &component,
+  GVArray get_varray_for_context(const CurvesGeometry &curves,
                                  eAttrDomain domain,
                                  IndexMask mask) const final;
   uint64_t hash() const override;
diff --git a/source/blender/blenkernel/BKE_geometry_set.h b/source/blender/blenkernel/BKE_geometry_set.h
index a28e9e6bdf6..97e69f3fe1f 100644
--- a/source/blender/blenkernel/BKE_geometry_set.h
+++ b/source/blender/blenkernel/BKE_geometry_set.h
@@ -23,9 +23,10 @@ typedef enum GeometryComponentType {
   GEO_COMPONENT_TYPE_INSTANCES = 2,
   GEO_COMPONENT_TYPE_VOLUME = 3,
   GEO_COMPONENT_TYPE_CURVE = 4,
+  GEO_COMPONENT_TYPE_EDIT = 5,
 } GeometryComponentType;
 
-#define GEO_COMPONENT_TYPE_ENUM_SIZE 5
+#define GEO_COMPONENT_TYPE_ENUM_SIZE 6
 
 void BKE_geometry_set_free(struct GeometrySet *geometry_set);
 
diff --git a/source/blender/blenkernel/BKE_geometry_set.hh b/source/blender/blenkernel/BKE_geometry_set.hh
index 4108e2f7e2e..2ef9556afc7 100644
--- a/source/blender/blenkernel/BKE_geometry_set.hh
+++ b/source/blender/blenkernel/BKE_geometry_set.hh
@@ -26,7 +26,6 @@
 struct Curves;
 struct Collection;
 struct Curve;
-struct CurveEval;
 struct Mesh;
 struct Object;
 struct PointCloud;
@@ -43,7 +42,8 @@ enum class GeometryOwnershipType {
 
 namespace blender::bke {
 class ComponentAttributeProviders;
-}
+class CurvesEditHints;
+}  // namespace blender::bke
 
 class GeometryComponent;
 
@@ -168,6 +168,12 @@ struct GeometrySet {
    * Remove all geometry components with types that are not in the provided list.
    */
   void keep_only(const blender::Span component_types);
+  /**
+   * Keeps the provided geometry types, but also instances and edit data.
+   * Instances must not be removed while using #modify_geometry_sets.
+   */
+  void keep_only_during_modify(const blender::Span component_types);
+  void remove_geometry_during_modify();
 
   void add(const GeometryComponent &component);
 
@@ -287,6 +293,10 @@ struct GeometrySet {
    * Returns a read-only curves data-block or null.
    */
   const Curves *get_curves_for_read() const;
+  /**
+   * Returns read-only curve edit hints or null.
+   */
+  const blender::bke::CurvesEditHints *get_curve_edit_hints_for_read() const;
 
   /**
    * Returns a mutable mesh or null. No ownership is transferred.
@@ -304,6 +314,10 @@ struct GeometrySet {
    * Returns a mutable curves data-block or null. No ownership is transferred.
    */
   Curves *get_curves_for_write();
+  /**
+   * Returns mutable curve edit hints or null.
+   */
+  blender::bke::CurvesEditHints *get_curve_edit_hints_for_write();
 
   /* Utility methods for replacement. */
   /**
@@ -450,47 +464,8 @@ class PointCloudComponent : public GeometryComponent {
 };
 
 /**
- * Legacy runtime-only curves type.
- * These curves are stored differently than other geometry components, because the data structure
- * used here does not correspond exactly to the #Curve DNA data structure. A #CurveEval is stored
- * here instead, though the component does give access to a #Curve for interfacing with render
- * engines and other areas of Blender that expect to use a data-block with an #ID.
- */
-class CurveComponentLegacy : public GeometryComponent {
- private:
-  CurveEval *curve_ = nullptr;
-  GeometryOwnershipType ownership_ = GeometryOwnershipType::Owned;
-
- public:
-  CurveComponentLegacy();
-  ~CurveComponentLegacy();
-  GeometryComponent *copy() const override;
-
-  void clear();
-  bool has_curve() const;
-  /**
-   * Clear the component and replace it with the new curve.
-   */
-  void replace(CurveEval *curve, GeometryOwnershipType ownership = GeometryOwnershipType::Owned);
-  CurveEval *release();
-
-  const CurveEval *get_for_read() const;
-  CurveEval *get_for_write();
-
-  bool is_empty() const final;
-
-  bool owns_direct_data() const override;
-  void ensure_owns_direct_data() override;
-
-  std::optional attributes() const final;
-  std::optional attributes_for_write() final;
-
-  static constexpr inline GeometryComponentType static_type = GEO_COMPONENT_TYPE_CURVE;
-};
-
-/**
- * A geometry component that stores a group of curves, corresponding the #Curves data-block type
- * and the #CurvesGeometry type. Attributes are are stored on the control point domain and the
+ * A geometry component that stores a group of curves, corresponding the #Curves data-block
+ * and the #CurvesGeometry type. Attributes are stored on the control point domain and the
  * curve domain.
  */
 class CurveComponent : public GeometryComponent {
@@ -499,10 +474,9 @@ class CurveComponent : public GeometryComponent {
   GeometryOwnershipType ownership_ = GeometryOwnershipType::Owned;
 
   /**
-   * Curve data necessary to hold the draw cache for rendering, consistent over multiple redraws.
-   * This is necessary because Blender assumes that objects evaluate to an object data type, and
-   * we use #CurveEval rather than #Curve here. It also allows us to mostly reuse the same
-   * batch cache implementation.
+   * Because rendering #Curves isn't fully working yet, we must provide a #Curve for the render
+   * engine and depsgraph object iterator in some cases. This allows using the old curve rendering
+   * even when the new curve data structure is used.
    */
   mutable Curve *curve_for_render_ = nullptr;
   mutable std::mutex curve_for_render_mutex_;
@@ -825,3 +799,37 @@ class VolumeComponent : public GeometryComponent {
 
   static constexpr inline GeometryComponentType static_type = GEO_COMPONENT_TYPE_VOLUME;
 };
+
+/**
+ * When the original data is in some edit mode, we want to propagate some additional information
+ * through object evaluation. This information can be used by edit modes to support working on
+ * evaluated data.
+ *
+ * This component is added at the beginning of modifier evaluation.
+ */
+class GeometryComponentEditData final : public GeometryComponent {
+ public:
+  /**
+   * Information about how original curves are manipulated during evaluation. This data is used so
+   * that curve sculpt tools can work on evaluated data. It is not stored in #CurveComponent
+   * because the data remains valid even when there is no actual curves geometry anymore, for
+   * example, when the curves have been converted to a mesh.
+   */
+  std::unique_ptr curves_edit_hints_;
+
+  GeometryComponentEditData();
+
+  GeometryComponent *copy() const final;
+  bool owns_direct_data() const final;
+  void ensure_owns_direct_data() final;
+
+  /**
+   * The first node that does topology changing operations on curves should store the curve point
+   * positions it retrieved as input. Without this, information about the deformed positions is
+   * lost, which would make curves sculpt mode fall back to using original curve positions instead
+   * of deformed ones.
+   */
+  static void remember_deformed_curve_positions_if_necessary(GeometrySet &geometry);
+
+  static constexpr inline GeometryComponentType static_type = GEO_COMPONENT_TYPE_EDIT;
+};
diff --git a/source/blender/blenkernel/BKE_global.h b/source/blender/blenkernel/BKE_global.h
index 96b6f7a53b0..e28c87cd7d6 100644
--- a/source/blender/blenkernel/BKE_global.h
+++ b/source/blender/blenkernel/BKE_global.h
@@ -80,7 +80,7 @@ typedef struct Global {
    *   *     -1: Disable faster motion paths computation (since 08/2018).
    *   * 1 - 30: EEVEE debug/stats values (01/2018).
    *   *     31: Enable the Select Debug Engine. Only available with #WITH_DRAW_DEBUG (08/2021).
-   *   *    101: Enable UI debug drawing of fullscreen area's corner widget (10/2014).
+   *   *    101: Enable UI debug drawing of full-screen area's corner widget (10/2014).
    *   *    102: Enable extra items in string search UI (05/2022).
    *   *    666: Use quicker batch delete for outliners' delete hierarchy (01/2019).
    *   *    777: Enable UI node panel's sockets polling (11/2011).
diff --git a/source/blender/blenkernel/BKE_gpencil_geom.h b/source/blender/blenkernel/BKE_gpencil_geom.h
index ad3b1971ca9..b9219814c08 100644
--- a/source/blender/blenkernel/BKE_gpencil_geom.h
+++ b/source/blender/blenkernel/BKE_gpencil_geom.h
@@ -401,12 +401,19 @@ void BKE_gpencil_stroke_set_random_color(struct bGPDstroke *gps);
 
 /**
  * Join two strokes using the shortest distance (reorder stroke if necessary).
+ * \param auto_flip: Flip the stroke if the join between two strokes is not end->start points.
  */
 void BKE_gpencil_stroke_join(struct bGPDstroke *gps_a,
                              struct bGPDstroke *gps_b,
                              bool leave_gaps,
                              bool fit_thickness,
-                             bool smooth);
+                             bool smooth,
+                             bool auto_flip);
+/**
+ * Set stroke start point in the selected index. Only works for Cyclic strokes.
+ * \param start_idx: Index of the point to be the start point.
+ */
+void BKE_gpencil_stroke_start_set(struct bGPDstroke *gps, int start_idx);
 /**
  * Copy the stroke of the frame to all frames selected (except current).
  */
@@ -466,8 +473,8 @@ void BKE_gpencil_stroke_uniform_subdivide(struct bGPdata *gpd,
  * This allows for manipulations in 2D but also easy conversion back to 3D.
  * \note also takes care of parent space transform.
  */
-void BKE_gpencil_stroke_to_view_space(struct RegionView3D *rv3d,
-                                      struct bGPDstroke *gps,
+void BKE_gpencil_stroke_to_view_space(struct bGPDstroke *gps,
+                                      float viewmat[4][4],
                                       const float diff_mat[4][4]);
 /**
  * Stroke from view space
@@ -475,20 +482,21 @@ void BKE_gpencil_stroke_to_view_space(struct RegionView3D *rv3d,
  * Inverse of #BKE_gpencil_stroke_to_view_space
  * \note also takes care of parent space transform.
  */
-void BKE_gpencil_stroke_from_view_space(struct RegionView3D *rv3d,
-                                        struct bGPDstroke *gps,
+void BKE_gpencil_stroke_from_view_space(struct bGPDstroke *gps,
+                                        float viewinv[4][4],
                                         const float diff_mat[4][4]);
 /**
  * Calculates the perimeter of a stroke projected from the view and returns it as a new stroke.
  * \param subdivisions: Number of subdivisions for the start and end caps.
  * \return: bGPDstroke pointer to stroke perimeter.
  */
-struct bGPDstroke *BKE_gpencil_stroke_perimeter_from_view(struct RegionView3D *rv3d,
+struct bGPDstroke *BKE_gpencil_stroke_perimeter_from_view(float viewmat[4][4],
                                                           struct bGPdata *gpd,
                                                           const struct bGPDlayer *gpl,
                                                           struct bGPDstroke *gps,
                                                           int subdivisions,
-                                                          const float diff_mat[4][4]);
+                                                          const float diff_mat[4][4],
+                                                          const float thickness_chg);
 /**
  * Get average pressure.
  */
diff --git a/source/blender/blenkernel/BKE_icons.h b/source/blender/blenkernel/BKE_icons.h
index 8d9351806c4..10d17c7f4c8 100644
--- a/source/blender/blenkernel/BKE_icons.h
+++ b/source/blender/blenkernel/BKE_icons.h
@@ -20,6 +20,8 @@ extern "C" {
 
 #include "BLI_compiler_attrs.h"
 
+#include "DNA_ID_enums.h"
+
 typedef void (*DrawInfoFreeFP)(void *drawinfo);
 
 enum {
@@ -77,8 +79,6 @@ struct PreviewImage;
 struct StudioLight;
 struct bGPDlayer;
 
-enum eIconSizes;
-
 void BKE_icons_init(int first_dyn_id);
 
 /**
diff --git a/source/blender/blenkernel/BKE_idprop.h b/source/blender/blenkernel/BKE_idprop.h
index 3f7d9498e39..9ac4b4e4619 100644
--- a/source/blender/blenkernel/BKE_idprop.h
+++ b/source/blender/blenkernel/BKE_idprop.h
@@ -7,6 +7,7 @@
  */
 
 #include "BLI_compiler_attrs.h"
+#include "BLI_sys_types.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -19,6 +20,7 @@ struct BlendWriter;
 struct ID;
 struct IDProperty;
 struct IDPropertyUIData;
+struct Library;
 
 typedef union IDPropertyTemplate {
   int i;
@@ -96,7 +98,7 @@ void IDP_AssignID(struct IDProperty *prop, struct ID *id, int flag);
  * Sync values from one group to another when values name and types match,
  * copy the values, else ignore.
  *
- * \note Use for syncing proxies.
+ * \note Was used for syncing proxies.
  */
 void IDP_SyncGroupValues(struct IDProperty *dest, const struct IDProperty *src) ATTR_NONNULL();
 void IDP_SyncGroupTypes(struct IDProperty *dest, const struct IDProperty *src, bool do_arraylen)
@@ -318,7 +320,7 @@ void IDP_BlendReadData_impl(struct BlendDataReader *reader,
                             struct IDProperty **prop,
                             const char *caller_func_id);
 #define IDP_BlendDataRead(reader, prop) IDP_BlendReadData_impl(reader, prop, __func__)
-void IDP_BlendReadLib(struct BlendLibReader *reader, struct IDProperty *prop);
+void IDP_BlendReadLib(struct BlendLibReader *reader, struct Library *lib, struct IDProperty *prop);
 void IDP_BlendReadExpand(struct BlendExpander *expander, struct IDProperty *prop);
 
 typedef enum eIDPropertyUIDataType {
@@ -326,7 +328,7 @@ typedef enum eIDPropertyUIDataType {
   IDP_UI_DATA_TYPE_UNSUPPORTED = -1,
   /** IDP_INT or IDP_ARRAY with subtype IDP_INT. */
   IDP_UI_DATA_TYPE_INT = 0,
-  /** IDP_FLOAT and IDP_DOUBLE or IDP_ARRAY properties with a float or double subtypes. */
+  /** IDP_FLOAT and IDP_DOUBLE or IDP_ARRAY properties with a float or double sub-types. */
   IDP_UI_DATA_TYPE_FLOAT = 1,
   /** IDP_STRING properties. */
   IDP_UI_DATA_TYPE_STRING = 2,
diff --git a/source/blender/blenkernel/BKE_idprop.hh b/source/blender/blenkernel/BKE_idprop.hh
index 1e741cc252f..e8ac4119970 100644
--- a/source/blender/blenkernel/BKE_idprop.hh
+++ b/source/blender/blenkernel/BKE_idprop.hh
@@ -45,8 +45,11 @@ std::unique_ptr create(StringRefNull prop_name, d
 std::unique_ptr create(StringRefNull prop_name,
                                                       const StringRefNull value);
 
+/** \brief Allocate a new IDProperty of type IDP_ID, set its name and value. */
+std::unique_ptr create(StringRefNull prop_name, ID *id);
+
 /**
- * \brief Allocate a new IDProperty of type IDP_ARRAY and subtype IDP_INT.
+ * \brief Allocate a new IDProperty of type IDP_ARRAY and sub-type IDP_INT.
  *
  * \param values: The values will be copied into the IDProperty.
  */
@@ -54,14 +57,14 @@ std::unique_ptr create(StringRefNull prop_name,
                                                       Span values);
 
 /**
- * \brief Allocate a new IDProperty of type IDP_ARRAY and subtype IDP_FLOAT.
+ * \brief Allocate a new IDProperty of type IDP_ARRAY and sub-type IDP_FLOAT.
  *
  * \param values: The values will be copied into the IDProperty.
  */
 std::unique_ptr create(StringRefNull prop_name, Span values);
 
 /**
- * \brief Allocate a new IDProperty of type IDP_ARRAY and subtype IDP_DOUBLE.
+ * \brief Allocate a new IDProperty of type IDP_ARRAY and sub-type IDP_DOUBLE.
  *
  * \param values: The values will be copied into the IDProperty.
  */
diff --git a/source/blender/blenkernel/BKE_idtype.h b/source/blender/blenkernel/BKE_idtype.h
index 30f7ed45859..256ddec5505 100644
--- a/source/blender/blenkernel/BKE_idtype.h
+++ b/source/blender/blenkernel/BKE_idtype.h
@@ -85,7 +85,7 @@ typedef void (*IDTypeForeachCacheFunction)(struct ID *id,
 
 typedef void (*IDTypeForeachPathFunction)(struct ID *id, struct BPathForeachPathData *bpath_data);
 
-typedef struct ID *(*IDTypeEmbeddedOwnerGetFunction)(struct Main *bmain, struct ID *id);
+typedef struct ID **(*IDTypeEmbeddedOwnerPointerGetFunction)(struct ID *id);
 
 typedef void (*IDTypeBlendWriteFunction)(struct BlendWriter *writer,
                                          struct ID *id,
@@ -109,7 +109,7 @@ typedef struct IDTypeInfo {
    */
   short id_code;
   /**
-   * Bitflag matching id_code, used for filtering (e.g. in file browser), see DNA_ID.h's
+   * Bit-flag matching id_code, used for filtering (e.g. in file browser), see DNA_ID.h's
    * FILTER_ID_XX enums.
    */
   uint64_t id_filter;
@@ -180,9 +180,9 @@ typedef struct IDTypeInfo {
   IDTypeForeachPathFunction foreach_path;
 
   /**
-   * For embedded IDs, return their owner ID.
+   * For embedded IDs, return the address of the pointer to their owner ID.
    */
-  IDTypeEmbeddedOwnerGetFunction owner_get;
+  IDTypeEmbeddedOwnerPointerGetFunction owner_pointer_get;
 
   /* ********** Callbacks for reading and writing .blend files. ********** */
 
diff --git a/source/blender/blenkernel/BKE_image.h b/source/blender/blenkernel/BKE_image.h
index 6ec1285af0c..eb43ce823ac 100644
--- a/source/blender/blenkernel/BKE_image.h
+++ b/source/blender/blenkernel/BKE_image.h
@@ -6,6 +6,7 @@
  * \ingroup bke
  */
 
+#include "BLI_compiler_attrs.h"
 #include "BLI_utildefines.h"
 
 #include "BLI_rect.h"
@@ -97,7 +98,7 @@ int BKE_imbuf_write(struct ImBuf *ibuf, const char *name, const struct ImageForm
  */
 int BKE_imbuf_write_as(struct ImBuf *ibuf,
                        const char *name,
-                       struct ImageFormatData *imf,
+                       const struct ImageFormatData *imf,
                        bool save_copy);
 
 /**
@@ -236,11 +237,13 @@ void BKE_image_ensure_viewer_views(const struct RenderData *rd,
  */
 void BKE_image_user_frame_calc(struct Image *ima, struct ImageUser *iuser, int cfra);
 int BKE_image_user_frame_get(const struct ImageUser *iuser, int cfra, bool *r_is_in_range);
-void BKE_image_user_file_path(struct ImageUser *iuser, struct Image *ima, char *path);
-void BKE_image_user_file_path_ex(struct ImageUser *iuser,
-                                 struct Image *ima,
+void BKE_image_user_file_path(const struct ImageUser *iuser, const struct Image *ima, char *path);
+void BKE_image_user_file_path_ex(const struct Main *bmain,
+                                 const struct ImageUser *iuser,
+                                 const struct Image *ima,
                                  char *path,
-                                 bool resolve_udim);
+                                 const bool resolve_udim,
+                                 const bool resolve_multiview);
 void BKE_image_editors_update_frame(const struct Main *bmain, int cfra);
 
 /**
@@ -258,15 +261,15 @@ struct RenderPass *BKE_image_multilayer_index(struct RenderResult *rr, struct Im
 /**
  * Sets index offset for multi-view files.
  */
-void BKE_image_multiview_index(struct Image *ima, struct ImageUser *iuser);
+void BKE_image_multiview_index(const struct Image *ima, struct ImageUser *iuser);
 
 /**
  * For multi-layer images as well as for render-viewer
  * and because rendered results use fake layer/passes, don't correct for wrong indices here.
  */
-bool BKE_image_is_multilayer(struct Image *ima);
-bool BKE_image_is_multiview(struct Image *ima);
-bool BKE_image_is_stereo(struct Image *ima);
+bool BKE_image_is_multilayer(const struct Image *ima);
+bool BKE_image_is_multiview(const struct Image *ima);
+bool BKE_image_is_stereo(const struct Image *ima);
 struct RenderResult *BKE_image_acquire_renderresult(struct Scene *scene, struct Image *ima);
 void BKE_image_release_renderresult(struct Scene *scene, struct Image *ima);
 
@@ -363,14 +366,7 @@ bool BKE_image_remove_tile(struct Image *ima, struct ImageTile *tile);
 void BKE_image_reassign_tile(struct Image *ima, struct ImageTile *tile, int new_tile_number);
 void BKE_image_sort_tiles(struct Image *ima);
 
-bool BKE_image_fill_tile(struct Image *ima,
-                         struct ImageTile *tile,
-                         int width,
-                         int height,
-                         const float color[4],
-                         int gen_type,
-                         int planes,
-                         bool is_float);
+bool BKE_image_fill_tile(struct Image *ima, struct ImageTile *tile);
 
 typedef enum {
   UDIM_TILE_FORMAT_NONE = 0,
@@ -422,9 +418,13 @@ int BKE_image_get_tile_from_pos(struct Image *ima,
 void BKE_image_get_tile_uv(const struct Image *ima, const int tile_number, float r_uv[2]);
 
 /**
- * Return the tile_number for the closest UDIM tile.
+ * Return the tile_number for the closest UDIM tile to `co`.
  */
-int BKE_image_find_nearest_tile(const struct Image *image, const float co[2]);
+int BKE_image_find_nearest_tile_with_offset(const struct Image *image,
+                                            const float co[2],
+                                            float r_uv_offset[2]) ATTR_NONNULL(2, 3);
+int BKE_image_find_nearest_tile(const struct Image *image, const float co[2])
+    ATTR_NONNULL(2) ATTR_WARN_UNUSED_RESULT;
 
 void BKE_image_get_size(struct Image *image, struct ImageUser *iuser, int *r_width, int *r_height);
 void BKE_image_get_size_fl(struct Image *image, struct ImageUser *iuser, float r_size[2]);
diff --git a/source/blender/blenkernel/BKE_image_format.h b/source/blender/blenkernel/BKE_image_format.h
index 6a03d1d8df5..8f71e1f4648 100644
--- a/source/blender/blenkernel/BKE_image_format.h
+++ b/source/blender/blenkernel/BKE_image_format.h
@@ -69,7 +69,7 @@ char BKE_imtype_valid_depths(char imtype);
  * String is from command line `--render-format` argument,
  * keep in sync with `creator_args.c` help info.
  */
-char BKE_imtype_from_arg(const char *arg);
+char BKE_imtype_from_arg(const char *imtype_arg);
 
 /* Conversion between ImBuf settings. */
 
diff --git a/source/blender/blenkernel/BKE_image_save.h b/source/blender/blenkernel/BKE_image_save.h
index 673a7dffb82..e17136174eb 100644
--- a/source/blender/blenkernel/BKE_image_save.h
+++ b/source/blender/blenkernel/BKE_image_save.h
@@ -48,14 +48,14 @@ bool BKE_image_save_options_init(ImageSaveOptions *opts,
                                  struct ImageUser *iuser,
                                  const bool guess_path,
                                  const bool save_as_render);
-void BKE_image_save_options_update(struct ImageSaveOptions *opts, struct Image *ima);
+void BKE_image_save_options_update(struct ImageSaveOptions *opts, const struct Image *ima);
 void BKE_image_save_options_free(struct ImageSaveOptions *opts);
 
 bool BKE_image_save(struct ReportList *reports,
                     struct Main *bmain,
                     struct Image *ima,
                     struct ImageUser *iuser,
-                    struct ImageSaveOptions *opts);
+                    const struct ImageSaveOptions *opts);
 
 /* Render saving. */
 
diff --git a/source/blender/blenkernel/BKE_key.h b/source/blender/blenkernel/BKE_key.h
index 676ac6fe37b..0fe351c0aa4 100644
--- a/source/blender/blenkernel/BKE_key.h
+++ b/source/blender/blenkernel/BKE_key.h
@@ -22,7 +22,7 @@ extern "C" {
 #endif
 
 /**
- * Free (or release) any data used by this shapekey (does not free the key itself).
+ * Free (or release) any data used by this shape-key (does not free the key itself).
  */
 void BKE_key_free_data(struct Key *key);
 void BKE_key_free_nolib(struct Key *key);
@@ -46,8 +46,11 @@ void key_curve_normal_weights(float t, float data[4], int type);
 
 /**
  * Returns key coordinates (+ tilt) when key applied, NULL otherwise.
+ *
+ * \param obdata: if given, also update that geometry with the result of the shape keys evaluation.
  */
-float *BKE_key_evaluate_object_ex(struct Object *ob, int *r_totelem, float *arr, size_t arr_size);
+float *BKE_key_evaluate_object_ex(
+    struct Object *ob, int *r_totelem, float *arr, size_t arr_size, struct ID *obdata);
 float *BKE_key_evaluate_object(struct Object *ob, int *r_totelem);
 
 /**
@@ -92,6 +95,9 @@ struct KeyBlock *BKE_keyblock_from_key(struct Key *key, int index);
  * Get the appropriate #KeyBlock given a name to search for.
  */
 struct KeyBlock *BKE_keyblock_find_name(struct Key *key, const char name[]);
+
+struct KeyBlock *BKE_keyblock_find_uid(struct Key *key, int uid);
+
 /**
  * \brief copy shape-key attributes, but not key data or name/UID.
  */
diff --git a/source/blender/blenkernel/BKE_lattice.h b/source/blender/blenkernel/BKE_lattice.h
index 9fa59c9e81b..aa4b1c69d24 100644
--- a/source/blender/blenkernel/BKE_lattice.h
+++ b/source/blender/blenkernel/BKE_lattice.h
@@ -27,7 +27,6 @@ void BKE_lattice_resize(struct Lattice *lt, int u, int v, int w, struct Object *
 struct Lattice *BKE_lattice_add(struct Main *bmain, const char *name);
 void calc_lat_fudu(int flag, int res, float *r_fu, float *r_du);
 
-bool object_deform_mball(struct Object *ob, struct ListBase *dispbase);
 void outside_lattice(struct Lattice *lt);
 
 float (*BKE_lattice_vert_coords_alloc(const struct Lattice *lt, int *r_vert_len))[3];
diff --git a/source/blender/blenkernel/BKE_layer.h b/source/blender/blenkernel/BKE_layer.h
index 3e4f2fe154e..8cfc9ef8be9 100644
--- a/source/blender/blenkernel/BKE_layer.h
+++ b/source/blender/blenkernel/BKE_layer.h
@@ -10,6 +10,7 @@
 
 #include "DNA_layer_types.h"
 #include "DNA_listBase.h"
+#include "DNA_object_enums.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -77,7 +78,9 @@ void BKE_view_layer_free_ex(struct ViewLayer *view_layer, bool do_id_user);
 /**
  * Tag all the selected objects of a render-layer.
  */
-void BKE_view_layer_selected_objects_tag(struct ViewLayer *view_layer, int tag);
+void BKE_view_layer_selected_objects_tag(const struct Scene *scene,
+                                         struct ViewLayer *view_layer,
+                                         int tag);
 
 /**
  * Fallback for when a Scene has no camera to use.
@@ -86,14 +89,14 @@ void BKE_view_layer_selected_objects_tag(struct ViewLayer *view_layer, int tag);
  * If rendering you pass the scene active layer, when viewing in the viewport
  * you want to get #ViewLayer from context.
  */
-struct Object *BKE_view_layer_camera_find(struct ViewLayer *view_layer);
+struct Object *BKE_view_layer_camera_find(const struct Scene *scene, struct ViewLayer *view_layer);
 /**
  * Find the #ViewLayer a #LayerCollection belongs to.
  */
 struct ViewLayer *BKE_view_layer_find_from_collection(const struct Scene *scene,
                                                       struct LayerCollection *lc);
 struct Base *BKE_view_layer_base_find(struct ViewLayer *view_layer, struct Object *ob);
-void BKE_view_layer_base_deselect_all(struct ViewLayer *view_layer);
+void BKE_view_layer_base_deselect_all(const struct Scene *scene, struct ViewLayer *view_layer);
 
 void BKE_view_layer_base_select_and_set_active(struct ViewLayer *view_layer, struct Base *selbase);
 
@@ -160,7 +163,9 @@ void BKE_scene_collection_sync(const struct Scene *scene);
  * and on file loaded in case linked data changed or went missing.
  */
 void BKE_layer_collection_sync(const struct Scene *scene, struct ViewLayer *view_layer);
-void BKE_layer_collection_local_sync(struct ViewLayer *view_layer, const struct View3D *v3d);
+void BKE_layer_collection_local_sync(const struct Scene *scene,
+                                     struct ViewLayer *view_layer,
+                                     const struct View3D *v3d);
 /**
  * Sync the local collection for all the 3D Viewports.
  */
@@ -191,10 +196,12 @@ bool BKE_scene_has_object(struct Scene *scene, struct Object *ob);
  * It also select the objects that are in nested collections.
  * \note Recursive.
  */
-bool BKE_layer_collection_objects_select(struct ViewLayer *view_layer,
+bool BKE_layer_collection_objects_select(const struct Scene *scene,
+                                         struct ViewLayer *view_layer,
                                          struct LayerCollection *lc,
                                          bool deselect);
-bool BKE_layer_collection_has_selected_objects(struct ViewLayer *view_layer,
+bool BKE_layer_collection_has_selected_objects(const struct Scene *scene,
+                                               struct ViewLayer *view_layer,
                                                struct LayerCollection *lc);
 bool BKE_layer_collection_has_layer_collection(struct LayerCollection *lc_parent,
                                                struct LayerCollection *lc_child);
@@ -225,7 +232,8 @@ void BKE_layer_collection_isolate_global(struct Scene *scene,
  *
  * Same as #BKE_layer_collection_isolate_local but for a viewport
  */
-void BKE_layer_collection_isolate_local(struct ViewLayer *view_layer,
+void BKE_layer_collection_isolate_local(const struct Scene *scene,
+                                        struct ViewLayer *view_layer,
                                         const struct View3D *v3d,
                                         struct LayerCollection *lc,
                                         bool extend);
@@ -234,7 +242,8 @@ void BKE_layer_collection_isolate_local(struct ViewLayer *view_layer,
  * Don't change the collection children enable/disable state,
  * but it may change it for the collection itself.
  */
-void BKE_layer_collection_set_visible(struct ViewLayer *view_layer,
+void BKE_layer_collection_set_visible(const struct Scene *scene,
+                                      struct ViewLayer *view_layer,
                                       struct LayerCollection *lc,
                                       bool visible,
                                       bool hierarchy);
@@ -244,8 +253,8 @@ void BKE_layer_collection_set_flag(struct LayerCollection *lc, int flag, bool va
 
 /**
  * Applies object's restrict flags on top of flags coming from the collection
- * and stores those in `base->flag`. #BASE_VISIBLE_DEPSGRAPH ignores viewport flags visibility
- * (i.e., restriction and local collection).
+ * and stores those in `base->flag`. #BASE_ENABLED_AND_MAYBE_VISIBLE_IN_VIEWPORT ignores viewport
+ * flags visibility (i.e., restriction and local collection).
  */
 void BKE_base_eval_flags(struct Base *base);
 
@@ -255,7 +264,9 @@ void BKE_layer_eval_view_layer_indexed(struct Depsgraph *depsgraph,
 
 /* .blend file I/O */
 
-void BKE_view_layer_blend_write(struct BlendWriter *writer, struct ViewLayer *view_layer);
+void BKE_view_layer_blend_write(struct BlendWriter *writer,
+                                const struct Scene *scene,
+                                struct ViewLayer *view_layer);
 void BKE_view_layer_blend_read_data(struct BlendDataReader *reader, struct ViewLayer *view_layer);
 void BKE_view_layer_blend_read_lib(struct BlendLibReader *reader,
                                    struct Library *lib,
@@ -351,15 +362,17 @@ void BKE_view_layer_visible_bases_iterator_end(BLI_Iterator *iter);
   } \
   ((void)0)
 
-#define FOREACH_BASE_IN_MODE_BEGIN(_view_layer, _v3d, _object_type, _object_mode, _instance) \
+#define FOREACH_BASE_IN_MODE_BEGIN( \
+    _scene, _view_layer, _v3d, _object_type, _object_mode, _instance) \
   { \
-    struct ObjectsInModeIteratorData data_ = { \
-        .object_mode = _object_mode, \
-        .object_type = _object_type, \
-        .view_layer = _view_layer, \
-        .v3d = _v3d, \
-        .base_active = _view_layer->basact, \
-    }; \
+    struct ObjectsInModeIteratorData data_; \
+    memset(&data_, 0, sizeof(data_)); \
+    data_.object_mode = _object_mode; \
+    data_.object_type = _object_type; \
+    data_.view_layer = _view_layer; \
+    data_.v3d = _v3d; \
+    BKE_view_layer_synced_ensure(_scene, _view_layer); \
+    data_.base_active = BKE_view_layer_active_base_get(_view_layer); \
     ITER_BEGIN (BKE_view_layer_bases_in_mode_iterator_begin, \
                 BKE_view_layer_bases_in_mode_iterator_next, \
                 BKE_view_layer_bases_in_mode_iterator_end, \
@@ -372,21 +385,22 @@ void BKE_view_layer_visible_bases_iterator_end(BLI_Iterator *iter);
   } \
   ((void)0)
 
-#define FOREACH_BASE_IN_EDIT_MODE_BEGIN(_view_layer, _v3d, _instance) \
-  FOREACH_BASE_IN_MODE_BEGIN (_view_layer, _v3d, -1, OB_MODE_EDIT, _instance)
+#define FOREACH_BASE_IN_EDIT_MODE_BEGIN(_scene, _view_layer, _v3d, _instance) \
+  FOREACH_BASE_IN_MODE_BEGIN (_scene, _view_layer, _v3d, -1, OB_MODE_EDIT, _instance)
 
 #define FOREACH_BASE_IN_EDIT_MODE_END FOREACH_BASE_IN_MODE_END
 
-#define FOREACH_OBJECT_IN_MODE_BEGIN(_view_layer, _v3d, _object_type, _object_mode, _instance) \
-  FOREACH_BASE_IN_MODE_BEGIN (_view_layer, _v3d, _object_type, _object_mode, _base) { \
+#define FOREACH_OBJECT_IN_MODE_BEGIN( \
+    _scene, _view_layer, _v3d, _object_type, _object_mode, _instance) \
+  FOREACH_BASE_IN_MODE_BEGIN (_scene, _view_layer, _v3d, _object_type, _object_mode, _base) { \
     Object *_instance = _base->object;
 
 #define FOREACH_OBJECT_IN_MODE_END \
   } \
   FOREACH_BASE_IN_MODE_END
 
-#define FOREACH_OBJECT_IN_EDIT_MODE_BEGIN(_view_layer, _v3d, _instance) \
-  FOREACH_BASE_IN_EDIT_MODE_BEGIN (_view_layer, _v3d, _base) { \
+#define FOREACH_OBJECT_IN_EDIT_MODE_BEGIN(_scene, _view_layer, _v3d, _instance) \
+  FOREACH_BASE_IN_EDIT_MODE_BEGIN (_scene, _view_layer, _v3d, _base) { \
     Object *_instance = _base->object;
 
 #define FOREACH_OBJECT_IN_EDIT_MODE_END \
@@ -403,11 +417,12 @@ void BKE_view_layer_visible_bases_iterator_end(BLI_Iterator *iter);
 
 #define FOREACH_SELECTED_BASE_END ITER_END
 
-#define FOREACH_VISIBLE_BASE_BEGIN(_view_layer, _v3d, _instance) \
+#define FOREACH_VISIBLE_BASE_BEGIN(_scene, _view_layer, _v3d, _instance) \
   { \
     struct ObjectsVisibleIteratorData data_ = {NULL}; \
     data_.view_layer = _view_layer; \
     data_.v3d = _v3d; \
+    BKE_view_layer_synced_ensure(_scene, _view_layer); \
     ITER_BEGIN (BKE_view_layer_visible_bases_iterator_begin, \
                 BKE_view_layer_visible_bases_iterator_next, \
                 BKE_view_layer_visible_bases_iterator_end, \
@@ -420,11 +435,13 @@ void BKE_view_layer_visible_bases_iterator_end(BLI_Iterator *iter);
   } \
   ((void)0)
 
-#define FOREACH_OBJECT_BEGIN(view_layer, _instance) \
+#define FOREACH_OBJECT_BEGIN(scene, view_layer, _instance) \
   { \
     Object *_instance; \
     Base *_base; \
-    for (_base = (Base *)(view_layer)->object_bases.first; _base; _base = _base->next) { \
+    BKE_view_layer_synced_ensure(scene, view_layer); \
+    for (_base = (Base *)BKE_view_layer_object_bases_get(view_layer)->first; _base; \
+         _base = _base->next) { \
       _instance = _base->object;
 
 #define FOREACH_OBJECT_END \
@@ -493,7 +510,8 @@ struct Object **BKE_view_layer_array_selected_objects_params(
  * Returns NULL with it finds multiple other selected objects
  * as behavior in this case would be random from the user perspective.
  */
-struct Object *BKE_view_layer_non_active_selected_object(struct ViewLayer *view_layer,
+struct Object *BKE_view_layer_non_active_selected_object(const struct Scene *scene,
+                                                         struct ViewLayer *view_layer,
                                                          const struct View3D *v3d);
 
 #define BKE_view_layer_array_selected_objects(view_layer, v3d, r_len, ...) \
@@ -509,57 +527,63 @@ struct ObjectsInModeParams {
 };
 
 struct Base **BKE_view_layer_array_from_bases_in_mode_params(
+    const struct Scene *scene,
     struct ViewLayer *view_layer,
     const struct View3D *v3d,
     uint *r_len,
     const struct ObjectsInModeParams *params);
 
 struct Object **BKE_view_layer_array_from_objects_in_mode_params(
+    const struct Scene *scene,
     struct ViewLayer *view_layer,
     const struct View3D *v3d,
     uint *len,
     const struct ObjectsInModeParams *params);
 
-#define BKE_view_layer_array_from_objects_in_mode(view_layer, v3d, r_len, ...) \
-  BKE_view_layer_array_from_objects_in_mode_params( \
-      view_layer, v3d, r_len, &(const struct ObjectsInModeParams)__VA_ARGS__)
-
-#define BKE_view_layer_array_from_bases_in_mode(view_layer, v3d, r_len, ...) \
-  BKE_view_layer_array_from_bases_in_mode_params( \
-      view_layer, v3d, r_len, &(const struct ObjectsInModeParams)__VA_ARGS__)
-
 bool BKE_view_layer_filter_edit_mesh_has_uvs(const struct Object *ob, void *user_data);
 bool BKE_view_layer_filter_edit_mesh_has_edges(const struct Object *ob, void *user_data);
 
-/* Utility macros that wrap common args (add more as needed). */
-
-#define BKE_view_layer_array_from_objects_in_edit_mode(view_layer, v3d, r_len) \
-  BKE_view_layer_array_from_objects_in_mode(view_layer, v3d, r_len, {.object_mode = OB_MODE_EDIT})
-
-#define BKE_view_layer_array_from_bases_in_edit_mode(view_layer, v3d, r_len) \
-  BKE_view_layer_array_from_bases_in_mode(view_layer, v3d, r_len, {.object_mode = OB_MODE_EDIT})
+/* Utility functions that wrap common arguments (add more as needed). */
+
+struct Object **BKE_view_layer_array_from_objects_in_edit_mode(const struct Scene *scene,
+                                                               struct ViewLayer *view_layer,
+                                                               const struct View3D *v3d,
+                                                               uint *r_len);
+struct Base **BKE_view_layer_array_from_bases_in_edit_mode(const struct Scene *scene,
+                                                           struct ViewLayer *view_layer,
+                                                           const struct View3D *v3d,
+                                                           uint *r_len);
+struct Object **BKE_view_layer_array_from_objects_in_edit_mode_unique_data(
+    const struct Scene *scene,
+    struct ViewLayer *view_layer,
+    const struct View3D *v3d,
+    uint *r_len);
 
-#define BKE_view_layer_array_from_objects_in_edit_mode_unique_data(view_layer, v3d, r_len) \
-  BKE_view_layer_array_from_objects_in_mode( \
-      view_layer, v3d, r_len, {.object_mode = OB_MODE_EDIT, .no_dup_data = true})
+struct Base **BKE_view_layer_array_from_bases_in_edit_mode_unique_data(
+    const struct Scene *scene,
+    struct ViewLayer *view_layer,
+    const struct View3D *v3d,
+    uint *r_len);
+struct Object **BKE_view_layer_array_from_objects_in_edit_mode_unique_data_with_uvs(
+    const struct Scene *scene,
+    struct ViewLayer *view_layer,
+    const struct View3D *v3d,
+    uint *r_len);
+struct Object **BKE_view_layer_array_from_objects_in_mode_unique_data(const struct Scene *scene,
+                                                                      struct ViewLayer *view_layer,
+                                                                      const struct View3D *v3d,
+                                                                      uint *r_len,
+                                                                      eObjectMode mode);
+struct Object *BKE_view_layer_active_object_get(const struct ViewLayer *view_layer);
+struct Object *BKE_view_layer_edit_object_get(const struct ViewLayer *view_layer);
 
-#define BKE_view_layer_array_from_bases_in_edit_mode_unique_data(view_layer, v3d, r_len) \
-  BKE_view_layer_array_from_bases_in_mode( \
-      view_layer, v3d, r_len, {.object_mode = OB_MODE_EDIT, .no_dup_data = true})
+struct ListBase *BKE_view_layer_object_bases_get(struct ViewLayer *view_layer);
+struct Base *BKE_view_layer_active_base_get(struct ViewLayer *view_layer);
 
-#define BKE_view_layer_array_from_objects_in_edit_mode_unique_data_with_uvs( \
-    view_layer, v3d, r_len) \
-  BKE_view_layer_array_from_objects_in_mode( \
-      view_layer, \
-      v3d, \
-      r_len, \
-      {.object_mode = OB_MODE_EDIT, \
-       .no_dup_data = true, \
-       .filter_fn = BKE_view_layer_filter_edit_mesh_has_uvs})
+struct LayerCollection *BKE_view_layer_active_collection_get(struct ViewLayer *view_layer);
 
-#define BKE_view_layer_array_from_objects_in_mode_unique_data(view_layer, v3d, r_len, mode) \
-  BKE_view_layer_array_from_objects_in_mode( \
-      view_layer, v3d, r_len, {.object_mode = mode, .no_dup_data = true})
+void BKE_view_layer_need_resync_tag(struct ViewLayer *view_layer);
+void BKE_view_layer_synced_ensure(const struct Scene *scene, struct ViewLayer *view_layer);
 
 struct ViewLayerAOV *BKE_view_layer_add_aov(struct ViewLayer *view_layer);
 void BKE_view_layer_remove_aov(struct ViewLayer *view_layer, struct ViewLayerAOV *aov);
@@ -590,7 +614,8 @@ void BKE_view_layer_set_active_lightgroup(struct ViewLayer *view_layer,
                                           struct ViewLayerLightgroup *lightgroup);
 struct ViewLayer *BKE_view_layer_find_with_lightgroup(
     struct Scene *scene, struct ViewLayerLightgroup *view_layer_lightgroup);
-void BKE_view_layer_rename_lightgroup(ViewLayer *view_layer,
+void BKE_view_layer_rename_lightgroup(struct Scene *scene,
+                                      ViewLayer *view_layer,
                                       ViewLayerLightgroup *lightgroup,
                                       const char *name);
 
diff --git a/source/blender/blenkernel/BKE_lib_id.h b/source/blender/blenkernel/BKE_lib_id.h
index beac608a138..aa3bdb502f8 100644
--- a/source/blender/blenkernel/BKE_lib_id.h
+++ b/source/blender/blenkernel/BKE_lib_id.h
@@ -77,19 +77,19 @@ void BKE_libblock_runtime_reset_remapping_status(struct ID *id) ATTR_NONNULL(1);
 /* *** ID's session_uuid management. *** */
 
 /**
- * When an ID's uuid is of that value, it is unset/invalid (e.g. for runtime IDs, etc.).
+ * When an ID's UUID is of that value, it is unset/invalid (e.g. for runtime IDs, etc.).
  */
 #define MAIN_ID_SESSION_UUID_UNSET 0
 
 /**
- * Generate a session-wise uuid for the given \a id.
+ * Generate a session-wise UUID for the given \a id.
  *
  * \note "session-wise" here means while editing a given .blend file. Once a new .blend file is
- * loaded or created, undo history is cleared/reset, and so is the uuid counter.
+ * loaded or created, undo history is cleared/reset, and so is the UUID counter.
  */
 void BKE_lib_libblock_session_uuid_ensure(struct ID *id);
 /**
- * Re-generate a new session-wise uuid for the given \a id.
+ * Re-generate a new session-wise UUID for the given \a id.
  *
  * \warning This has a few very specific use-cases, no other usage is expected currently:
  *   - To handle UI-related data-blocks that are kept across new file reading, when we do keep
@@ -117,14 +117,14 @@ void *BKE_id_new_nomain(short type, const char *name);
  */
 enum {
   /* *** Generic options (should be handled by all ID types copying, ID creation, etc.). *** */
-  /** Create datablock outside of any main database -
+  /** Create data-block outside of any main database -
    * similar to 'localize' functions of materials etc. */
   LIB_ID_CREATE_NO_MAIN = 1 << 0,
-  /** Do not affect user refcount of datablocks used by new one
-   * (which also gets zero usercount then).
+  /** Do not affect user refcount of data-blocks used by new one
+   * (which also gets zero user-count then).
    * Implies LIB_ID_CREATE_NO_MAIN. */
   LIB_ID_CREATE_NO_USER_REFCOUNT = 1 << 1,
-  /** Assume given 'newid' already points to allocated memory for whole datablock
+  /** Assume given 'newid' already points to allocated memory for whole data-block
    * (ID + data) - USE WITH CAUTION!
    * Implies LIB_ID_CREATE_NO_MAIN. */
   LIB_ID_CREATE_NO_ALLOCATE = 1 << 2,
@@ -150,7 +150,7 @@ enum {
   LIB_ID_COPY_NO_PREVIEW = 1 << 17,
   /** Copy runtime data caches. */
   LIB_ID_COPY_CACHES = 1 << 18,
-  /** Don't copy id->adt, used by ID data-block localization routines. */
+  /** Don't copy `id->adt`, used by ID data-block localization routines. */
   LIB_ID_COPY_NO_ANIMDATA = 1 << 19,
   /** Mesh: Reference CD data layers instead of doing real copy - USE WITH CAUTION! */
   LIB_ID_COPY_CD_REFERENCE = 1 << 20,
@@ -239,12 +239,12 @@ enum {
   /** Do not try to remove freed ID from given Main (passed Main may be NULL). */
   LIB_ID_FREE_NO_MAIN = 1 << 0,
   /**
-   * Do not affect user refcount of datablocks used by freed one.
+   * Do not affect user refcount of data-blocks used by freed one.
    * Implies LIB_ID_FREE_NO_MAIN.
    */
   LIB_ID_FREE_NO_USER_REFCOUNT = 1 << 1,
   /**
-   * Assume freed ID datablock memory is managed elsewhere, do not free it
+   * Assume freed ID data-block memory is managed elsewhere, do not free it
    * (still calls relevant ID type's freeing function though) - USE WITH CAUTION!
    * Implies LIB_ID_FREE_NO_MAIN.
    */
@@ -254,6 +254,8 @@ enum {
   LIB_ID_FREE_NO_DEG_TAG = 1 << 8,
   /** Do not attempt to remove freed ID from UI data/notifiers/... */
   LIB_ID_FREE_NO_UI_USER = 1 << 9,
+  /** Do not remove freed ID's name from a potential runtime name-map. */
+  LIB_ID_FREE_NO_NAMEMAP_REMOVE = 1 << 10,
 };
 
 void BKE_libblock_free_datablock(struct ID *id, int flag) ATTR_NONNULL();
@@ -281,7 +283,7 @@ void BKE_libblock_free_data_py(struct ID *id);
  * \param idv: Pointer to ID to be freed.
  * \param flag: Set of \a LIB_ID_FREE_... flags controlling/overriding usual freeing process,
  * 0 to get default safe behavior.
- * \param use_flag_from_idtag: Still use freeing info flags from given #ID datablock,
+ * \param use_flag_from_idtag: Still use freeing info flags from given #ID data-block,
  * even if some overriding ones are passed in \a flag parameter.
  */
 void BKE_id_free_ex(struct Main *bmain, void *idv, int flag, bool use_flag_from_idtag);
@@ -298,7 +300,7 @@ void BKE_id_free(struct Main *bmain, void *idv);
 
 /**
  * Not really a freeing function by itself,
- * it decrements usercount of given id, and only frees it if it reaches 0.
+ * it decrements user-count of given id, and only frees it if it reaches 0.
  */
 void BKE_id_free_us(struct Main *bmain, void *idv) ATTR_NONNULL();
 
@@ -314,12 +316,12 @@ void BKE_id_delete(struct Main *bmain, void *idv) ATTR_NONNULL();
  *
  * \warning Considered experimental for now, seems to be working OK but this is
  * risky code in a complicated area.
- * \return Number of deleted datablocks.
+ * \return Number of deleted data-blocks.
  */
 size_t BKE_id_multi_tagged_delete(struct Main *bmain) ATTR_NONNULL();
 
 /**
- * Add a 'NO_MAIN' data-block to given main (also sets usercounts of its IDs if needed).
+ * Add a 'NO_MAIN' data-block to given main (also sets user-counts of its IDs if needed).
  */
 void BKE_libblock_management_main_add(struct Main *bmain, void *idv);
 /** Remove a data-block from given main (set it to 'NO_MAIN' status). */
@@ -398,12 +400,9 @@ bool id_single_user(struct bContext *C,
                     struct ID *id,
                     struct PointerRNA *ptr,
                     struct PropertyRNA *prop);
+
+/** Test whether given `id` can be copied or not. */
 bool BKE_id_copy_is_allowed(const struct ID *id);
-/**
- * Invokes the appropriate copy method for the block and returns the result in
- * #ID.newid, unless test. Returns true if the block can be copied.
- */
-struct ID *BKE_id_copy(struct Main *bmain, const struct ID *id);
 /**
  * Generic entry point for copying a data-block (new API).
  *
@@ -428,14 +427,39 @@ struct ID *BKE_id_copy(struct Main *bmain, const struct ID *id);
  */
 struct ID *BKE_id_copy_ex(struct Main *bmain, const struct ID *id, struct ID **r_newid, int flag);
 /**
- * Invokes the appropriate copy method for the block and returns the result in
- * newid, unless test. Returns true if the block can be copied.
+ * Invoke the appropriate copy method for the block and return the new id as result.
+ *
+ * See #BKE_id_copy_ex for details.
+ */
+struct ID *BKE_id_copy(struct Main *bmain, const struct ID *id);
+
+/**
+ * Invoke the appropriate copy method for the block and return the new id as result.
+ *
+ * Unlike #BKE_id_copy, it does set the #ID.newid pointer of the given `id` to the copied one.
+ *
+ * It is designed as a basic common helper for the higher-level 'duplicate' operations (aka 'deep
+ * copy' of data-blocks and some of their dependency ones), see e.g. #BKE_object_duplicate.
+ *
+ * Currently, it only handles the given ID, and their shape keys and actions if any, according to
+ * the given `duplicate_flags`.
+ *
+ * \param duplicate_flags: is of type #eDupli_ID_Flags, see #UserDef.dupflag. Currently only
+ * `USER_DUP_LINKED_ID` and `USER_DUP_ACT` have an effect here.
+ * \param copy_flags: flags passed to #BKE_id_copy_ex.
  */
 struct ID *BKE_id_copy_for_duplicate(struct Main *bmain,
                                      struct ID *id,
                                      uint duplicate_flags,
                                      int copy_flags);
 
+/**
+ * Special version of #BKE_id_copy which is safe from using evaluated id as source with a copy
+ * result appearing in the main database.
+ * Takes care of the referenced data-blocks consistency.
+ */
+struct ID *BKE_id_copy_for_use_in_bmain(struct Main *bmain, const struct ID *id);
+
 /**
  * Does a mere memory swap over the whole IDs data (including type-specific memory).
  * \note Most internal ID data itself is not swapped (only IDProperties are).
@@ -478,10 +502,12 @@ void BKE_lib_id_expand_local(struct Main *bmain, struct ID *id, int flags);
  *
  * \return true if a new name had to be created.
  */
-bool BKE_id_new_name_validate(struct ListBase *lb,
+bool BKE_id_new_name_validate(struct Main *bmain,
+                              struct ListBase *lb,
                               struct ID *id,
                               const char *name,
-                              bool do_linked_data) ATTR_NONNULL(1, 2);
+                              bool do_linked_data) ATTR_NONNULL(1, 2, 3);
+
 /**
  * Pull an ID out of a library (make it local). Only call this for IDs that
  * don't have other library users.
@@ -526,7 +552,7 @@ void BKE_main_lib_objects_recalc_all(struct Main *bmain);
 /**
  * Only for repairing files via versioning, avoid for general use.
  */
-void BKE_main_id_repair_duplicate_names_listbase(struct ListBase *lb);
+void BKE_main_id_repair_duplicate_names_listbase(struct Main *bmain, struct ListBase *lb);
 
 #define MAX_ID_FULL_NAME (64 + 64 + 3 + 1)         /* 64 is MAX_ID_NAME - 2 */
 #define MAX_ID_FULL_NAME_UI (MAX_ID_FULL_NAME + 3) /* Adds 'keycode' two letters at beginning. */
@@ -594,6 +620,13 @@ bool BKE_id_is_in_global_main(struct ID *id);
 
 bool BKE_id_can_be_asset(const struct ID *id);
 
+/**
+ * Return the owner ID of the given `id`, if any.
+ *
+ * \note This will only return non-NULL for embedded IDs (master collections etc.), and shape-keys.
+ */
+struct ID *BKE_id_owner_get(struct ID *id);
+
 /** Check if that ID can be considered as editable from a high-level (editor) perspective.
  *
  * NOTE: This used to be done with a check on whether ID was linked or not, but now with system
diff --git a/source/blender/blenkernel/BKE_lib_override.h b/source/blender/blenkernel/BKE_lib_override.h
index b2162e651fd..8542c02fab5 100644
--- a/source/blender/blenkernel/BKE_lib_override.h
+++ b/source/blender/blenkernel/BKE_lib_override.h
@@ -59,6 +59,21 @@ void BKE_lib_override_library_clear(struct IDOverrideLibrary *override, bool do_
  */
 void BKE_lib_override_library_free(struct IDOverrideLibrary **override, bool do_id_user);
 
+/**
+ * Return the actual #IDOverrideLibrary data 'controlling' the given `id`, and the actual ID owning
+ * it.
+ *
+ * \note This is especially useful when `id` is a non-real override (e.g. embedded ID like a master
+ * collection or root node tree, or a shape key).
+ *
+ * \param owner_id_hint: If not NULL, a potential owner for the given override-embedded `id`.
+ * \param r_owner_id: If given, will be set with the actual ID owning the return liboverride data.
+ */
+IDOverrideLibrary *BKE_lib_override_library_get(struct Main *bmain,
+                                                struct ID *id,
+                                                struct ID *owner_id_hint,
+                                                struct ID **r_owner_id);
+
 /**
  * Check if given ID has some override rules that actually indicate the user edited it.
  */
diff --git a/source/blender/blenkernel/BKE_lib_principle_properties.h b/source/blender/blenkernel/BKE_lib_principle_properties.h
deleted file mode 100644
index 42177204efb..00000000000
--- a/source/blender/blenkernel/BKE_lib_principle_properties.h
+++ /dev/null
@@ -1,85 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later
- * Copyright 2022 Blender Foundation. All rights reserved. */
-
-#pragma once
-
-/** \file
- * \ingroup bke
- *
- * API to manage principle properties in data-blocks.
- *
- * Principle properties are properties that are defined as the ones most user will need to
- * edit when using this data-block.
- *
- * They current main usage in is library overrides.
- *
- * \note `BKE_lib_` files are for operations over data-blocks themselves, although they might
- * alter Main as well (when creating/renaming/deleting an ID e.g.).
- *
- * \section Function Names
- *
- *  - `BKE_lib_principleprop_` should be used for function affecting a single ID.
- *  - `BKE_lib_principleprop_main_` should be used for function affecting the whole collection
- *    of IDs in a given Main data-base.
- */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-struct ID;
-struct IDPrincipleProperties;
-struct IDPrincipleProperty;
-struct PointerRNA;
-struct PropertyRNA;
-struct ReportList;
-
-/**
- * Initialize empty list of principle properties for \a id.
- */
-struct IDPrincipleProperties *BKE_lib_principleprop_init(struct ID *id);
-#if 0
-/**
- * Shallow or deep copy of a whole principle properties from \a src_id to \a dst_id.
- */
-void BKE_lib_principleprop_copy(struct ID *dst_id, const struct ID *src_id, bool do_full_copy);
-#endif
-/**
- * Clear any principle properties data from given \a override.
- */
-void BKE_lib_principleprop_clear(struct IDPrincipleProperties *principle_props, bool do_id_user);
-/**
- * Free given \a principle_props.
- */
-void BKE_lib_principleprop_free(struct IDPrincipleProperties **principle_props, bool do_id_user);
-
-/**
- * Find principle property from given RNA path, if it exists.
- */
-struct IDPrincipleProperty *BKE_lib_principleprop_find(
-    struct IDPrincipleProperties *principle_props, const char *rna_path);
-/**
- * Find principle property from given RNA path, or create it if it does not exist.
- */
-struct IDPrincipleProperty *BKE_lib_principleprop_get(
-    struct IDPrincipleProperties *principle_props, const char *rna_path, bool *r_created);
-/**
- * Remove and free given \a principle_prop from given ID \a principle_props.
- */
-void BKE_lib_principleprop_delete(struct IDPrincipleProperties *principle_props,
-                                  struct IDPrincipleProperty *principle_prop);
-/**
- * Get the RNA-property matching the \a principle_prop principle property. Used for UI to query
- * additional data about the principle property (e.g. UI name).
- *
- * \param idpoin: RNA Pointer of the ID.
- * \param principle_prop: The principle property to find the matching RNA property for.
- */
-bool BKE_lib_principleprop_rna_property_find(struct PointerRNA *idpoin,
-                                             const struct IDPrincipleProperty *principle_prop,
-                                             struct PointerRNA *r_principle_poin,
-                                             struct PropertyRNA **r_principle_prop);
-
-#ifdef __cplusplus
-}
-#endif
diff --git a/source/blender/blenkernel/BKE_lib_query.h b/source/blender/blenkernel/BKE_lib_query.h
index 48cffcf8d2c..a70d128cd95 100644
--- a/source/blender/blenkernel/BKE_lib_query.h
+++ b/source/blender/blenkernel/BKE_lib_query.h
@@ -36,7 +36,6 @@ enum {
 
   /**
    * Indicates whether this is direct (i.e. by local data) or indirect (i.e. by linked data) usage.
-   * \note Object proxies are half-local, half-linked...
    */
   IDWALK_CB_INDIRECT_USAGE = (1 << 2),
 
diff --git a/source/blender/blenkernel/BKE_lib_remap.h b/source/blender/blenkernel/BKE_lib_remap.h
index 37b626fb4da..a17ef8c7c5d 100644
--- a/source/blender/blenkernel/BKE_lib_remap.h
+++ b/source/blender/blenkernel/BKE_lib_remap.h
@@ -180,12 +180,12 @@ typedef enum IDRemapperApplyResult {
 
 typedef enum IDRemapperApplyOptions {
   /**
-   * Update the user count of the old and new ID datablock.
+   * Update the user count of the old and new ID data-block.
    *
    * For remapping the old ID users will be decremented and the new ID users will be
    * incremented. When un-assigning the old ID users will be decremented.
    *
-   * NOTE: Currently unused by main remapping code, since usercount is handled by
+   * NOTE: Currently unused by main remapping code, since user-count is handled by
    * `foreach_libblock_remap_callback_apply` there, depending on whether the remapped pointer does
    * use it or not. Need for rare cases in UI handling though (see e.g. `image_id_remap` in
    * `space_image.c`).
@@ -193,14 +193,14 @@ typedef enum IDRemapperApplyOptions {
   ID_REMAP_APPLY_UPDATE_REFCOUNT = (1 << 0),
 
   /**
-   * Make sure that the new ID datablock will have a 'real' user.
+   * Make sure that the new ID data-block will have a 'real' user.
    *
    * NOTE: See Note for #ID_REMAP_APPLY_UPDATE_REFCOUNT above.
    */
   ID_REMAP_APPLY_ENSURE_REAL = (1 << 1),
 
   /**
-   * Unassign in stead of remap when the new ID datablock would become id_self.
+   * Unassign in stead of remap when the new ID data-block would become id_self.
    *
    * To use this option 'BKE_id_remapper_apply_ex' must be used with a not-null id_self parameter.
    */
diff --git a/source/blender/blenkernel/BKE_main.h b/source/blender/blenkernel/BKE_main.h
index 2c444f42c46..0048ad4dde5 100644
--- a/source/blender/blenkernel/BKE_main.h
+++ b/source/blender/blenkernel/BKE_main.h
@@ -36,6 +36,7 @@ struct IDNameLib_Map;
 struct ImBuf;
 struct Library;
 struct MainLock;
+struct UniqueName_Map;
 
 /* Blender thumbnail, as written on file (width, height, and data as char RGBA). */
 /* We pack pixel data after that struct. */
@@ -112,28 +113,30 @@ typedef struct Main {
   char filepath[1024];               /* 1024 = FILE_MAX */
   short versionfile, subversionfile; /* see BLENDER_FILE_VERSION, BLENDER_FILE_SUBVERSION */
   short minversionfile, minsubversionfile;
-  uint64_t build_commit_timestamp; /* commit's timestamp from buildinfo */
-  char build_hash[16];             /* hash from buildinfo */
+  /** Commit timestamp from `buildinfo`. */
+  uint64_t build_commit_timestamp;
+  /** Commit Hash from `buildinfo`. */
+  char build_hash[16];
   /** Indicate the #Main.filepath (file) is the recovered one. */
-  char recovered;
+  bool recovered;
   /** All current ID's exist in the last memfile undo step. */
-  char is_memfile_undo_written;
+  bool is_memfile_undo_written;
   /**
    * An ID needs its data to be flushed back.
    * use "needs_flush_to_id" in edit data to flag data which needs updating.
    */
-  char is_memfile_undo_flush_needed;
+  bool is_memfile_undo_flush_needed;
   /**
    * Indicates that next memfile undo step should not allow reusing old bmain when re-read, but
    * instead do a complete full re-read/update from stored memfile.
    */
-  char use_memfile_full_barrier;
+  bool use_memfile_full_barrier;
 
   /**
    * When linking, disallow creation of new data-blocks.
    * Make sure we don't do this by accident, see T76738.
    */
-  char is_locked_for_linking;
+  bool is_locked_for_linking;
 
   BlendThumbnail *blen_thumb;
 
@@ -193,6 +196,9 @@ typedef struct Main {
   /* IDMap of IDs. Currently used when reading (expanding) libraries. */
   struct IDNameLib_Map *id_map;
 
+  /* Used for efficient calculations of unique names. */
+  struct UniqueName_Map *name_map;
+
   struct MainLock *lock;
 } Main;
 
diff --git a/source/blender/blenkernel/BKE_main_namemap.h b/source/blender/blenkernel/BKE_main_namemap.h
new file mode 100644
index 00000000000..d6f184b4b30
--- /dev/null
+++ b/source/blender/blenkernel/BKE_main_namemap.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#pragma once
+
+/** \file
+ * \ingroup bke
+ *
+ * API to ensure name uniqueness.
+ *
+ * Main database contains the UniqueName_Map which is a cache that tracks names, base
+ * names and their suffixes currently in use. So that whenever a new name has to be
+ * assigned or validated, it can quickly ensure uniqueness and adjust the name in case
+ * of collisions.
+ *
+ * \section Function Names
+ *
+ * - `BKE_main_namemap_` Should be used for functions in this file.
+ */
+
+#include "BLI_compiler_attrs.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct ID;
+struct Main;
+struct UniqueName_Map;
+
+struct UniqueName_Map *BKE_main_namemap_create(void) ATTR_WARN_UNUSED_RESULT;
+void BKE_main_namemap_destroy(struct UniqueName_Map **r_name_map) ATTR_NONNULL();
+
+/**
+ * Ensures the given name is unique within the given ID type.
+ *
+ * In case of name collisions, the name will be adjusted to be unique.
+ *
+ * \return true if the name had to be adjusted for uniqueness.
+ */
+bool BKE_main_namemap_get_name(struct Main *bmain, struct ID *id, char *name) ATTR_NONNULL();
+
+/**
+ * Remove a given name from usage.
+ *
+ * Call this whenever deleting or renaming an object.
+ */
+void BKE_main_namemap_remove_name(struct Main *bmain, struct ID *id, const char *name)
+    ATTR_NONNULL();
+
+/**
+ * Check that all ID names in given `bmain` are unique (per ID type and library), and that existing
+ * name maps are consistent with existing relevant IDs.
+ *
+ * This is typically called within an assert, or in tests.
+ */
+bool BKE_main_namemap_validate(struct Main *bmain) ATTR_NONNULL();
+
+/** Same as #BKE_main_namemap_validate, but also fixes any issue by re-generating all name maps,
+ * and ensuring again all ID names are unique.
+ *
+ * This is typically only used in `do_versions` code to fix broken files.
+ */
+bool BKE_main_namemap_validate_and_fix(struct Main *bmain) ATTR_NONNULL();
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/source/blender/blenkernel/BKE_mball.h b/source/blender/blenkernel/BKE_mball.h
index a23d010b51f..5ffaa13d9d2 100644
--- a/source/blender/blenkernel/BKE_mball.h
+++ b/source/blender/blenkernel/BKE_mball.h
@@ -54,19 +54,10 @@ bool BKE_mball_is_basis(const struct Object *ob);
  */
 struct Object *BKE_mball_basis_find(struct Scene *scene, struct Object *ob);
 
-/**
- * Compute bounding box of all meta-elements / meta-ball.
- *
- * Bounding box is computed from polygonized surface. \a ob is
- * basic meta-balls (with name `Meta` for example). All other meta-ball objects
- * (with names `Meta.001`, `Meta.002`, etc) are included in this bounding-box.
- */
-void BKE_mball_texspace_calc(struct Object *ob);
 /**
  * Return or compute bounding-box for given meta-ball object.
  */
 struct BoundBox *BKE_mball_boundbox_get(struct Object *ob);
-float *BKE_mball_make_orco(struct Object *ob, struct ListBase *dispbase);
 
 /**
  * Copy some properties from a meta-ball obdata to all other meta-ball obdata belonging to the same
@@ -97,7 +88,7 @@ void BKE_mball_translate(struct MetaBall *mb, const float offset[3]);
  */
 struct MetaElem *BKE_mball_element_add(struct MetaBall *mb, int type);
 
-/* *** select funcs *** */
+/* *** Select functions *** */
 
 int BKE_mball_select_count(const struct MetaBall *mb);
 int BKE_mball_select_count_multi(struct Base **bases, int bases_len);
@@ -110,18 +101,7 @@ bool BKE_mball_select_swap_multi_ex(struct Base **bases, int bases_len);
 
 /* **** Depsgraph evaluation **** */
 
-struct Depsgraph;
-
-/* Draw Cache */
-
-enum {
-  BKE_MBALL_BATCH_DIRTY_ALL = 0,
-};
-void BKE_mball_batch_cache_dirty_tag(struct MetaBall *mb, int mode);
-void BKE_mball_batch_cache_free(struct MetaBall *mb);
-
-extern void (*BKE_mball_batch_cache_dirty_tag_cb)(struct MetaBall *mb, int mode);
-extern void (*BKE_mball_batch_cache_free_cb)(struct MetaBall *mb);
+void BKE_mball_data_update(struct Depsgraph *depsgraph, struct Scene *scene, struct Object *ob);
 
 #ifdef __cplusplus
 }
diff --git a/source/blender/blenkernel/BKE_mball_tessellate.h b/source/blender/blenkernel/BKE_mball_tessellate.h
index 2dc16dc64d6..0840c51bb4d 100644
--- a/source/blender/blenkernel/BKE_mball_tessellate.h
+++ b/source/blender/blenkernel/BKE_mball_tessellate.h
@@ -12,11 +12,11 @@ extern "C" {
 struct Depsgraph;
 struct Object;
 struct Scene;
+struct Mesh;
 
-void BKE_mball_polygonize(struct Depsgraph *depsgraph,
-                          struct Scene *scene,
-                          struct Object *ob,
-                          struct ListBase *dispbase);
+struct Mesh *BKE_mball_polygonize(struct Depsgraph *depsgraph,
+                                  struct Scene *scene,
+                                  struct Object *ob);
 
 void BKE_mball_cubeTable_free(void);
 
diff --git a/source/blender/blenkernel/BKE_mesh.h b/source/blender/blenkernel/BKE_mesh.h
index 366083fee7f..ef57c9a2e0e 100644
--- a/source/blender/blenkernel/BKE_mesh.h
+++ b/source/blender/blenkernel/BKE_mesh.h
@@ -6,10 +6,16 @@
  * \ingroup bke
  */
 
-#include "BKE_mesh_types.h"
 #include "BLI_compiler_attrs.h"
+#include "BLI_compiler_compat.h"
 #include "BLI_utildefines.h"
 
+#include "DNA_mesh_types.h"
+#include "DNA_meshdata_types.h"
+
+#include "BKE_customdata.h"
+#include "BKE_mesh_types.h"
+
 struct BLI_Stack;
 struct BMesh;
 struct BMeshCreateParams;
@@ -85,9 +91,17 @@ struct Mesh *BKE_mesh_from_bmesh_for_eval_nomain(struct BMesh *bm,
  * Add original index (#CD_ORIGINDEX) layers if they don't already exist. This is meant to be used
  * when creating an evaluated mesh from an original edit mode mesh, to allow mapping from the
  * evaluated vertices to the originals.
+ *
+ * The mesh is expected to of a `ME_WRAPPER_TYPE_MDATA` wrapper type. This is asserted.
  */
 void BKE_mesh_ensure_default_orig_index_customdata(struct Mesh *mesh);
 
+/**
+ * Same as #BKE_mesh_ensure_default_orig_index_customdata but does not perform any checks: they
+ * must be done by the caller.
+ */
+void BKE_mesh_ensure_default_orig_index_customdata_no_check(struct Mesh *mesh);
+
 /**
  * Find the index of the loop in 'poly' which references vertex,
  * returns -1 if not found
@@ -137,7 +151,6 @@ void BKE_mesh_copy_parameters_for_eval(struct Mesh *me_dst, const struct Mesh *m
  * when a new mesh is based on an existing mesh.
  */
 void BKE_mesh_copy_parameters(struct Mesh *me_dst, const struct Mesh *me_src);
-void BKE_mesh_update_customdata_pointers(struct Mesh *me, bool do_ensure_tess_cd);
 void BKE_mesh_ensure_skin_customdata(struct Mesh *me);
 
 struct Mesh *BKE_mesh_new_nomain(
@@ -185,7 +198,6 @@ void BKE_mesh_orco_ensure(struct Object *ob, struct Mesh *mesh);
 
 struct Mesh *BKE_mesh_from_object(struct Object *ob);
 void BKE_mesh_assign_object(struct Main *bmain, struct Object *ob, struct Mesh *me);
-void BKE_mesh_from_metaball(struct ListBase *lb, struct Mesh *me);
 void BKE_mesh_to_curve_nurblist(const struct Mesh *me,
                                 struct ListBase *nurblist,
                                 int edge_users_test);
@@ -280,13 +292,10 @@ struct Mesh *BKE_mesh_create_derived_for_modifier(struct Depsgraph *depsgraph,
                                                   bool build_shapekey_layers);
 
 /**
- * Copies a nomain-Mesh into an existing Mesh.
+ * Move data from a mesh outside of the main data-base into a mesh in the data-base.
+ * Takes ownership of the source mesh.
  */
-void BKE_mesh_nomain_to_mesh(struct Mesh *mesh_src,
-                             struct Mesh *mesh_dst,
-                             struct Object *ob,
-                             const struct CustomData_MeshMasks *mask,
-                             bool take_ownership);
+void BKE_mesh_nomain_to_mesh(struct Mesh *mesh_src, struct Mesh *mesh_dst, struct Object *ob);
 void BKE_mesh_nomain_to_meshkey(struct Mesh *mesh_src, struct Mesh *mesh_dst, struct KeyBlock *kb);
 
 /* vertex level transformations & checks (no derived mesh) */
@@ -322,7 +331,7 @@ void BKE_mesh_vert_coords_apply_with_mat4(struct Mesh *mesh,
                                           const float mat[4][4]);
 void BKE_mesh_vert_coords_apply(struct Mesh *mesh, const float (*vert_coords)[3]);
 
-/* *** mesh_tessellate.c *** */
+/* *** mesh_tessellate.cc *** */
 
 /**
  * Calculate tessellation into #MLoopTri which exist only for this purpose.
@@ -507,9 +516,9 @@ void BKE_edges_sharp_from_angle_set(const struct MVert *mverts,
                                     int numVerts,
                                     struct MEdge *medges,
                                     int numEdges,
-                                    struct MLoop *mloops,
+                                    const struct MLoop *mloops,
                                     int numLoops,
-                                    struct MPoly *mpolys,
+                                    const struct MPoly *mpolys,
                                     const float (*polynors)[3],
                                     int numPolys,
                                     float split_angle);
@@ -627,12 +636,12 @@ void BKE_lnor_space_custom_normal_to_data(MLoopNorSpace *lnor_space,
 void BKE_mesh_normals_loop_split(const struct MVert *mverts,
                                  const float (*vert_normals)[3],
                                  int numVerts,
-                                 struct MEdge *medges,
+                                 const struct MEdge *medges,
                                  int numEdges,
-                                 struct MLoop *mloops,
+                                 const struct MLoop *mloops,
                                  float (*r_loopnors)[3],
                                  int numLoops,
-                                 struct MPoly *mpolys,
+                                 const struct MPoly *mpolys,
                                  const float (*polynors)[3],
                                  int numPolys,
                                  bool use_split_normals,
@@ -646,25 +655,25 @@ void BKE_mesh_normals_loop_custom_set(const struct MVert *mverts,
                                       int numVerts,
                                       struct MEdge *medges,
                                       int numEdges,
-                                      struct MLoop *mloops,
+                                      const struct MLoop *mloops,
                                       float (*r_custom_loopnors)[3],
                                       int numLoops,
-                                      struct MPoly *mpolys,
+                                      const struct MPoly *mpolys,
                                       const float (*polynors)[3],
                                       int numPolys,
                                       short (*r_clnors_data)[2]);
-void BKE_mesh_normals_loop_custom_from_vertices_set(const struct MVert *mverts,
-                                                    const float (*vert_normals)[3],
-                                                    float (*r_custom_vertnors)[3],
-                                                    int numVerts,
-                                                    struct MEdge *medges,
-                                                    int numEdges,
-                                                    struct MLoop *mloops,
-                                                    int numLoops,
-                                                    struct MPoly *mpolys,
-                                                    const float (*polynors)[3],
-                                                    int numPolys,
-                                                    short (*r_clnors_data)[2]);
+void BKE_mesh_normals_loop_custom_from_verts_set(const struct MVert *mverts,
+                                                 const float (*vert_normals)[3],
+                                                 float (*r_custom_vertnors)[3],
+                                                 int numVerts,
+                                                 struct MEdge *medges,
+                                                 int numEdges,
+                                                 const struct MLoop *mloops,
+                                                 int numLoops,
+                                                 const struct MPoly *mpolys,
+                                                 const float (*polynors)[3],
+                                                 int numPolys,
+                                                 short (*r_clnors_data)[2]);
 
 /**
  * Computes average per-vertex normals from given custom loop normals.
@@ -705,12 +714,12 @@ void BKE_mesh_calc_normals_split_ex(struct Mesh *mesh,
 void BKE_mesh_set_custom_normals(struct Mesh *mesh, float (*r_custom_loopnors)[3]);
 /**
  * Higher level functions hiding most of the code needed around call to
- * #BKE_mesh_normals_loop_custom_from_vertices_set().
+ * #BKE_mesh_normals_loop_custom_from_verts_set().
  *
  * \param r_custom_vertnors: is not const, since code will replace zero_v3 normals there
  * with automatically computed vectors.
  */
-void BKE_mesh_set_custom_normals_from_vertices(struct Mesh *mesh, float (*r_custom_vertnors)[3]);
+void BKE_mesh_set_custom_normals_from_verts(struct Mesh *mesh, float (*r_custom_vertnors)[3]);
 
 /* *** mesh_evaluate.cc *** */
 
@@ -786,22 +795,24 @@ void BKE_mesh_mdisp_flip(struct MDisps *md, bool use_loop_mdisp_flip);
  * \param mloop: the full loops array.
  * \param ldata: the loops custom data.
  */
-void BKE_mesh_polygon_flip_ex(struct MPoly *mpoly,
+void BKE_mesh_polygon_flip_ex(const struct MPoly *mpoly,
                               struct MLoop *mloop,
                               struct CustomData *ldata,
                               float (*lnors)[3],
                               struct MDisps *mdisp,
                               bool use_loop_mdisp_flip);
-void BKE_mesh_polygon_flip(struct MPoly *mpoly, struct MLoop *mloop, struct CustomData *ldata);
+void BKE_mesh_polygon_flip(const struct MPoly *mpoly,
+                           struct MLoop *mloop,
+                           struct CustomData *ldata);
 /**
  * Flip (invert winding of) all polygons (used to inverse their normals).
  *
  * \note Invalidates tessellation, caller must handle that.
  */
-void BKE_mesh_polygons_flip(struct MPoly *mpoly,
-                            struct MLoop *mloop,
-                            struct CustomData *ldata,
-                            int totpoly);
+void BKE_mesh_polys_flip(const struct MPoly *mpoly,
+                         struct MLoop *mloop,
+                         struct CustomData *ldata,
+                         int totpoly);
 
 /* Merge verts. */
 /* Enum for merge_mode of #BKE_mesh_merge_verts.
@@ -845,7 +856,7 @@ struct Mesh *BKE_mesh_merge_verts(struct Mesh *mesh,
                                   int merge_mode);
 
 /**
- * Account for custom-data such as UV's becoming detached because of of imprecision
+ * Account for custom-data such as UV's becoming detached because of imprecision
  * in custom-data interpolation.
  * Without running this operation subdivision surface can cause UV's to be disconnected,
  * see: T81065.
@@ -857,19 +868,7 @@ void BKE_mesh_merge_customdata_for_apply_modifier(struct Mesh *me);
 /**
  * Update the hide flag for edges and faces from the corresponding flag in verts.
  */
-void BKE_mesh_flush_hidden_from_verts_ex(const struct MVert *mvert,
-                                         const struct MLoop *mloop,
-                                         struct MEdge *medge,
-                                         int totedge,
-                                         struct MPoly *mpoly,
-                                         int totpoly);
 void BKE_mesh_flush_hidden_from_verts(struct Mesh *me);
-void BKE_mesh_flush_hidden_from_polys_ex(struct MVert *mvert,
-                                         const struct MLoop *mloop,
-                                         struct MEdge *medge,
-                                         int totedge,
-                                         const struct MPoly *mpoly,
-                                         int totpoly);
 void BKE_mesh_flush_hidden_from_polys(struct Mesh *me);
 /**
  * simple poly -> vert/edge selection.
@@ -986,7 +985,7 @@ void BKE_mesh_strip_loose_edges(struct Mesh *me);
 
 /**
  * If the mesh is from a very old blender version,
- * convert mface->edcode to edge drawflags
+ * convert #MFace.edcode to edge #ME_EDGEDRAW.
  */
 void BKE_mesh_calc_edges_legacy(struct Mesh *me, bool use_old);
 void BKE_mesh_calc_edges_loose(struct Mesh *mesh);
@@ -1002,8 +1001,8 @@ void BKE_mesh_calc_edges(struct Mesh *mesh, bool keep_existing_edges, bool selec
 void BKE_mesh_calc_edges_tessface(struct Mesh *mesh);
 
 /* In DerivedMesh.cc */
-void BKE_mesh_wrapper_deferred_finalize(struct Mesh *me_eval,
-                                        const struct CustomData_MeshMasks *cd_mask_finalize);
+void BKE_mesh_wrapper_deferred_finalize_mdata(struct Mesh *me_eval,
+                                              const struct CustomData_MeshMasks *cd_mask_finalize);
 
 /* **** Depsgraph evaluation **** */
 
@@ -1024,6 +1023,138 @@ char *BKE_mesh_debug_info(const struct Mesh *me)
 void BKE_mesh_debug_print(const struct Mesh *me) ATTR_NONNULL(1);
 #endif
 
+/* -------------------------------------------------------------------- */
+/** \name Inline Mesh Data Access
+ * \{ */
+
+/**
+ * \return The material index for each polygon. May be null.
+ * \note In C++ code, prefer using the attribute API (#MutableAttributeAccessor)/
+ */
+BLI_INLINE const int *BKE_mesh_material_indices(const Mesh *mesh)
+{
+  return (const int *)CustomData_get_layer_named(&mesh->pdata, CD_PROP_INT32, "material_index");
+}
+
+/**
+ * \return The material index for each polygon. Create the layer if it doesn't exist.
+ * \note In C++ code, prefer using the attribute API (#MutableAttributeAccessor)/
+ */
+BLI_INLINE int *BKE_mesh_material_indices_for_write(Mesh *mesh)
+{
+  int *indices = (int *)CustomData_duplicate_referenced_layer_named(
+      &mesh->pdata, CD_PROP_INT32, "material_index", mesh->totpoly);
+  if (indices) {
+    return indices;
+  }
+  return (int *)CustomData_add_layer_named(
+      &mesh->pdata, CD_PROP_INT32, CD_SET_DEFAULT, NULL, mesh->totpoly, "material_index");
+}
+
+BLI_INLINE const MVert *BKE_mesh_verts(const Mesh *mesh)
+{
+  return (const MVert *)CustomData_get_layer(&mesh->vdata, CD_MVERT);
+}
+BLI_INLINE MVert *BKE_mesh_verts_for_write(Mesh *mesh)
+{
+  return (MVert *)CustomData_duplicate_referenced_layer(&mesh->vdata, CD_MVERT, mesh->totvert);
+}
+
+BLI_INLINE const MEdge *BKE_mesh_edges(const Mesh *mesh)
+{
+  return (const MEdge *)CustomData_get_layer(&mesh->edata, CD_MEDGE);
+}
+BLI_INLINE MEdge *BKE_mesh_edges_for_write(Mesh *mesh)
+{
+  return (MEdge *)CustomData_duplicate_referenced_layer(&mesh->edata, CD_MEDGE, mesh->totedge);
+}
+
+BLI_INLINE const MPoly *BKE_mesh_polys(const Mesh *mesh)
+{
+  return (const MPoly *)CustomData_get_layer(&mesh->pdata, CD_MPOLY);
+}
+BLI_INLINE MPoly *BKE_mesh_polys_for_write(Mesh *mesh)
+{
+  return (MPoly *)CustomData_duplicate_referenced_layer(&mesh->pdata, CD_MPOLY, mesh->totpoly);
+}
+
+BLI_INLINE const MLoop *BKE_mesh_loops(const Mesh *mesh)
+{
+  return (const MLoop *)CustomData_get_layer(&mesh->ldata, CD_MLOOP);
+}
+BLI_INLINE MLoop *BKE_mesh_loops_for_write(Mesh *mesh)
+{
+  return (MLoop *)CustomData_duplicate_referenced_layer(&mesh->ldata, CD_MLOOP, mesh->totloop);
+}
+
+BLI_INLINE const MDeformVert *BKE_mesh_deform_verts(const Mesh *mesh)
+{
+  return (const MDeformVert *)CustomData_get_layer(&mesh->vdata, CD_MDEFORMVERT);
+}
+BLI_INLINE MDeformVert *BKE_mesh_deform_verts_for_write(Mesh *mesh)
+{
+  MDeformVert *dvert = (MDeformVert *)CustomData_duplicate_referenced_layer(
+      &mesh->vdata, CD_MDEFORMVERT, mesh->totvert);
+  if (dvert) {
+    return dvert;
+  }
+  return (MDeformVert *)CustomData_add_layer(
+      &mesh->vdata, CD_MDEFORMVERT, CD_SET_DEFAULT, NULL, mesh->totvert);
+}
+
 #ifdef __cplusplus
 }
 #endif
+
+#ifdef __cplusplus
+
+#  include "BLI_span.hh"
+
+inline blender::Span Mesh::verts() const
+{
+  return {BKE_mesh_verts(this), this->totvert};
+}
+inline blender::MutableSpan Mesh::verts_for_write()
+{
+  return {BKE_mesh_verts_for_write(this), this->totvert};
+}
+
+inline blender::Span Mesh::edges() const
+{
+  return {BKE_mesh_edges(this), this->totedge};
+}
+inline blender::MutableSpan Mesh::edges_for_write()
+{
+  return {BKE_mesh_edges_for_write(this), this->totedge};
+}
+
+inline blender::Span Mesh::polys() const
+{
+  return {BKE_mesh_polys(this), this->totpoly};
+}
+inline blender::MutableSpan Mesh::polys_for_write()
+{
+  return {BKE_mesh_polys_for_write(this), this->totpoly};
+}
+
+inline blender::Span Mesh::loops() const
+{
+  return {BKE_mesh_loops(this), this->totloop};
+}
+inline blender::MutableSpan Mesh::loops_for_write()
+{
+  return {BKE_mesh_loops_for_write(this), this->totloop};
+}
+
+inline blender::Span Mesh::deform_verts() const
+{
+  return {BKE_mesh_deform_verts(this), this->totvert};
+}
+inline blender::MutableSpan Mesh::deform_verts_for_write()
+{
+  return {BKE_mesh_deform_verts_for_write(this), this->totvert};
+}
+
+#endif
+
+/** \} */
diff --git a/source/blender/blenkernel/BKE_mesh_fair.h b/source/blender/blenkernel/BKE_mesh_fair.h
index 0dc44ecb247..9d94c692858 100644
--- a/source/blender/blenkernel/BKE_mesh_fair.h
+++ b/source/blender/blenkernel/BKE_mesh_fair.h
@@ -25,16 +25,16 @@ typedef enum eMeshFairingDepth {
 
 /* affect_vertices is used to define the fairing area. Indexed by vertex index, set to true when
  * the vertex should be modified by fairing. */
-void BKE_bmesh_prefair_and_fair_vertices(struct BMesh *bm,
-                                         bool *affect_vertices,
-                                         eMeshFairingDepth depth);
+void BKE_bmesh_prefair_and_fair_verts(struct BMesh *bm,
+                                      bool *affect_verts,
+                                      eMeshFairingDepth depth);
 
 /* This function can optionally use the MVert coordinates of deform_mverts to read and write the
  * fairing result. When NULL, the function will use mesh->mverts directly. */
-void BKE_mesh_prefair_and_fair_vertices(struct Mesh *mesh,
-                                        struct MVert *deform_mverts,
-                                        bool *affect_vertices,
-                                        eMeshFairingDepth depth);
+void BKE_mesh_prefair_and_fair_verts(struct Mesh *mesh,
+                                     struct MVert *deform_mverts,
+                                     bool *affect_verts,
+                                     eMeshFairingDepth depth);
 
 #ifdef __cplusplus
 }
diff --git a/source/blender/blenkernel/BKE_mesh_legacy_convert.h b/source/blender/blenkernel/BKE_mesh_legacy_convert.h
index 909fd0e0dea..e67aec0b9ce 100644
--- a/source/blender/blenkernel/BKE_mesh_legacy_convert.h
+++ b/source/blender/blenkernel/BKE_mesh_legacy_convert.h
@@ -17,6 +17,35 @@ struct CustomData;
 struct Mesh;
 struct MFace;
 
+/**
+ * Copy bevel weights from separate layers into vertices and edges.
+ */
+void BKE_mesh_legacy_bevel_weight_from_layers(struct Mesh *mesh);
+/**
+ * Copy bevel weights from vertices and edges to separate layers.
+ */
+void BKE_mesh_legacy_bevel_weight_to_layers(struct Mesh *mesh);
+
+/**
+ * Convert the hidden element attributes to the old flag format for writing.
+ */
+void BKE_mesh_legacy_convert_hide_layers_to_flags(struct Mesh *mesh);
+/**
+ * Convert the old hide flags (#ME_HIDE) to the hidden element attribute for reading.
+ * Only add the attributes when there are any elements in each domain hidden.
+ */
+void BKE_mesh_legacy_convert_flags_to_hide_layers(struct Mesh *mesh);
+
+/**
+ * Move material indices from a generic attribute to #MPoly.
+ */
+void BKE_mesh_legacy_convert_material_indices_to_mpoly(struct Mesh *mesh);
+/**
+ * Move material indices from the #MPoly struct to a generic attributes.
+ * Only add the attribute when the indices are not all zero.
+ */
+void BKE_mesh_legacy_convert_mpoly_to_material_indices(struct Mesh *mesh);
+
 /**
  * Recreate #MFace Tessellation.
  *
diff --git a/source/blender/blenkernel/BKE_mesh_mapping.h b/source/blender/blenkernel/BKE_mesh_mapping.h
index 163acf062e0..cf9763d50a4 100644
--- a/source/blender/blenkernel/BKE_mesh_mapping.h
+++ b/source/blender/blenkernel/BKE_mesh_mapping.h
@@ -17,11 +17,10 @@ struct MLoopUV;
 struct MPoly;
 struct MVert;
 
-/* map from uv vertex to face (for select linked, stitch, uv suburf) */
-
 /* UvVertMap */
 #define STD_UV_CONNECT_LIMIT 0.0001f
 
+/* Map from uv vertex to face. Used by select linked, uv subdivision-surface and obj exporter. */
 typedef struct UvVertMap {
   struct UvMapVert **vert;
   struct UvMapVert *buf;
@@ -52,24 +51,38 @@ typedef struct UvElement {
   unsigned int island;
 } UvElement;
 
-/* UvElementMap is a container for UvElements of a mesh. It stores some UvElements belonging to the
- * same uv island in sequence and the number of uvs per island so it is possible to access all uvs
- * belonging to an island directly by iterating through the buffer.
+/** UvElementMap is a container for UvElements of a BMesh.
+ *
+ * It simplifies access to UV information and ensures the
+ * different UV selection modes are respected.
+ *
+ * If islands are calculated, it also stores UvElements
+ * belonging to the same uv island in sequence and
+ * the number of uvs per island.
  */
 typedef struct UvElementMap {
-  /* address UvElements by their vertex */
-  struct UvElement **vert;
-  /* UvElement Store */
-  struct UvElement *buf;
-  /* Total number of UVs in the layer. Useful to know */
-  int totalUVs;
-  /* Number of Islands in the mesh */
-  int totalIslands;
-  /* Stores the starting index in buf where each island begins */
-  int *islandIndices;
-} UvElementMap;
+  /** UvElement Storage. */
+  struct UvElement *storage;
+  /** Total number of UVs. */
+  int total_uvs;
+  /** Total number of unique UVs. */
+  int total_unique_uvs;
 
-#define INVALID_ISLAND ((unsigned int)-1)
+  /** If Non-NULL, address UvElements by `BM_elem_index_get(BMVert*)`. */
+  struct UvElement **vertex;
+
+  /** If Non-NULL, pointer to local head of each unique UV. */
+  struct UvElement **head_table;
+
+  /** Number of islands, or zero if not calculated. */
+  int total_islands;
+  /** Array of starting index in #storage where each island begins. */
+  int *island_indices;
+  /** Array of number of UVs in each island. */
+  int *island_total_uvs;
+  /** Array of number of unique UVs in each island. */
+  int *island_total_unique_uvs;
+} UvElementMap;
 
 /* Connectivity data */
 typedef struct MeshElemMap {
@@ -79,6 +92,7 @@ typedef struct MeshElemMap {
 
 /* mapping */
 UvVertMap *BKE_mesh_uv_vert_map_create(const struct MPoly *mpoly,
+                                       const bool *hide_poly,
                                        const struct MLoop *mloop,
                                        const struct MLoopUV *mloopuv,
                                        unsigned int totpoly,
@@ -234,13 +248,13 @@ void BKE_mesh_loop_islands_add(MeshIslandStore *island_store,
                                int num_innercut_items,
                                int *innercut_item_indices);
 
-typedef bool (*MeshRemapIslandsCalc)(struct MVert *verts,
+typedef bool (*MeshRemapIslandsCalc)(const struct MVert *verts,
                                      int totvert,
-                                     struct MEdge *edges,
+                                     const struct MEdge *edges,
                                      int totedge,
-                                     struct MPoly *polys,
+                                     const struct MPoly *polys,
                                      int totpoly,
-                                     struct MLoop *loops,
+                                     const struct MLoop *loops,
                                      int totloop,
                                      struct MeshIslandStore *r_island_store);
 
@@ -251,13 +265,13 @@ typedef bool (*MeshRemapIslandsCalc)(struct MVert *verts,
  * Calculate 'generic' UV islands, i.e. based only on actual geometry data (edge seams),
  * not some UV layers coordinates.
  */
-bool BKE_mesh_calc_islands_loop_poly_edgeseam(struct MVert *verts,
+bool BKE_mesh_calc_islands_loop_poly_edgeseam(const struct MVert *verts,
                                               int totvert,
-                                              struct MEdge *edges,
+                                              const struct MEdge *edges,
                                               int totedge,
-                                              struct MPoly *polys,
+                                              const struct MPoly *polys,
                                               int totpoly,
-                                              struct MLoop *loops,
+                                              const struct MLoop *loops,
                                               int totloop,
                                               MeshIslandStore *r_island_store);
 
diff --git a/source/blender/blenkernel/BKE_mesh_remap.h b/source/blender/blenkernel/BKE_mesh_remap.h
index ee0179c7a77..efbf542c831 100644
--- a/source/blender/blenkernel/BKE_mesh_remap.h
+++ b/source/blender/blenkernel/BKE_mesh_remap.h
@@ -199,13 +199,13 @@ void BKE_mesh_remap_calc_loops_from_mesh(int mode,
                                          float max_dist,
                                          float ray_radius,
                                          struct Mesh *mesh_dst,
-                                         struct MVert *verts_dst,
+                                         const struct MVert *verts_dst,
                                          int numverts_dst,
-                                         struct MEdge *edges_dst,
+                                         const struct MEdge *edges_dst,
                                          int numedges_dst,
-                                         struct MLoop *loops_dst,
+                                         const struct MLoop *loops_dst,
                                          int numloops_dst,
-                                         struct MPoly *polys_dst,
+                                         const struct MPoly *polys_dst,
                                          int numpolys_dst,
                                          struct CustomData *ldata_dst,
                                          bool use_split_nors_dst,
@@ -220,10 +220,10 @@ void BKE_mesh_remap_calc_polys_from_mesh(int mode,
                                          const struct SpaceTransform *space_transform,
                                          float max_dist,
                                          float ray_radius,
-                                         struct Mesh *mesh_dst,
-                                         struct MVert *verts_dst,
-                                         struct MLoop *loops_dst,
-                                         struct MPoly *polys_dst,
+                                         const struct Mesh *mesh_dst,
+                                         const struct MVert *verts_dst,
+                                         const struct MLoop *loops_dst,
+                                         const struct MPoly *polys_dst,
                                          int numpolys_dst,
                                          struct Mesh *me_src,
                                          struct MeshPairRemap *r_map);
diff --git a/source/blender/blenkernel/BKE_mesh_remesh_voxel.h b/source/blender/blenkernel/BKE_mesh_remesh_voxel.h
index dff17bd6575..d9f5a75ca61 100644
--- a/source/blender/blenkernel/BKE_mesh_remesh_voxel.h
+++ b/source/blender/blenkernel/BKE_mesh_remesh_voxel.h
@@ -28,9 +28,9 @@ struct Mesh *BKE_mesh_remesh_quadriflow(const struct Mesh *mesh,
                                         void *update_cb_data);
 
 /* Data reprojection functions */
-void BKE_mesh_remesh_reproject_paint_mask(struct Mesh *target, struct Mesh *source);
+void BKE_mesh_remesh_reproject_paint_mask(struct Mesh *target, const struct Mesh *source);
 void BKE_remesh_reproject_vertex_paint(struct Mesh *target, const struct Mesh *source);
-void BKE_remesh_reproject_sculpt_face_sets(struct Mesh *target, struct Mesh *source);
+void BKE_remesh_reproject_sculpt_face_sets(struct Mesh *target, const struct Mesh *source);
 
 #ifdef __cplusplus
 }
diff --git a/source/blender/blenkernel/BKE_mesh_sample.hh b/source/blender/blenkernel/BKE_mesh_sample.hh
index 356709d8942..94dc52d5ec9 100644
--- a/source/blender/blenkernel/BKE_mesh_sample.hh
+++ b/source/blender/blenkernel/BKE_mesh_sample.hh
@@ -13,7 +13,6 @@
 #include "DNA_meshdata_types.h"
 
 #include "BKE_attribute.h"
-#include "BKE_attribute.hh"
 
 struct Mesh;
 struct BVHTreeFromMesh;
@@ -27,22 +26,22 @@ namespace blender::bke::mesh_surface_sample {
 void sample_point_attribute(const Mesh &mesh,
                             Span looptri_indices,
                             Span bary_coords,
-                            const GVArray &data_in,
-                            const IndexMask mask,
-                            GMutableSpan data_out);
+                            const GVArray &src,
+                            IndexMask mask,
+                            GMutableSpan dst);
 
 void sample_corner_attribute(const Mesh &mesh,
                              Span looptri_indices,
                              Span bary_coords,
-                             const GVArray &data_in,
-                             const IndexMask mask,
-                             GMutableSpan data_out);
+                             const GVArray &src,
+                             IndexMask mask,
+                             GMutableSpan dst);
 
 void sample_face_attribute(const Mesh &mesh,
                            Span looptri_indices,
-                           const GVArray &data_in,
-                           const IndexMask mask,
-                           GMutableSpan data_out);
+                           const GVArray &src,
+                           IndexMask mask,
+                           GMutableSpan dst);
 
 enum class eAttributeMapMode {
   INTERPOLATED,
@@ -57,7 +56,6 @@ enum class eAttributeMapMode {
  * these are computed lazily when needed and re-used.
  */
 class MeshAttributeInterpolator {
- private:
   const Mesh *mesh_;
   const IndexMask mask_;
   const Span positions_;
@@ -68,18 +66,14 @@ class MeshAttributeInterpolator {
 
  public:
   MeshAttributeInterpolator(const Mesh *mesh,
-                            const IndexMask mask,
-                            const Span positions,
-                            const Span looptri_indices);
+                            IndexMask mask,
+                            Span positions,
+                            Span looptri_indices);
 
   void sample_data(const GVArray &src,
                    eAttrDomain domain,
                    eAttributeMapMode mode,
-                   const GMutableSpan dst);
-
-  void sample_attribute(const GAttributeReader &src_attribute,
-                        GSpanAttributeWriter &dst_attribute,
-                        eAttributeMapMode mode);
+                   GMutableSpan dst);
 
  protected:
   Span ensure_barycentric_coords();
@@ -133,8 +127,20 @@ int sample_surface_points_projected(
     Vector &r_looptri_indices,
     Vector &r_positions);
 
-float3 compute_bary_coord_in_triangle(const Mesh &mesh,
+float3 compute_bary_coord_in_triangle(Span verts,
+                                      Span loops,
                                       const MLoopTri &looptri,
                                       const float3 &position);
 
+template
+inline T sample_corner_attrribute_with_bary_coords(const float3 &bary_weights,
+                                                   const MLoopTri &looptri,
+                                                   const Span corner_attribute)
+{
+  return attribute_math::mix3(bary_weights,
+                              corner_attribute[looptri.tri[0]],
+                              corner_attribute[looptri.tri[1]],
+                              corner_attribute[looptri.tri[2]]);
+}
+
 }  // namespace blender::bke::mesh_surface_sample
diff --git a/source/blender/blenkernel/BKE_modifier.h b/source/blender/blenkernel/BKE_modifier.h
index 866b0353d07..f46672a5033 100644
--- a/source/blender/blenkernel/BKE_modifier.h
+++ b/source/blender/blenkernel/BKE_modifier.h
@@ -265,9 +265,7 @@ typedef struct ModifierTypeInfo {
    *
    * This function is optional.
    */
-  void (*requiredDataMask)(struct Object *ob,
-                           struct ModifierData *md,
-                           struct CustomData_MeshMasks *r_cddata_masks);
+  void (*requiredDataMask)(struct ModifierData *md, struct CustomData_MeshMasks *r_cddata_masks);
 
   /**
    * Free internal modifier data variables, this function should
@@ -446,10 +444,22 @@ bool BKE_modifier_is_enabled(const struct Scene *scene,
  */
 bool BKE_modifier_is_nonlocal_in_liboverride(const struct Object *ob,
                                              const struct ModifierData *md);
+
+/* Set modifier execution error.
+ * The message will be shown in the interface and will be logged as an error to the console. */
 void BKE_modifier_set_error(const struct Object *ob,
                             struct ModifierData *md,
                             const char *format,
                             ...) ATTR_PRINTF_FORMAT(3, 4);
+
+/* Set modifier execution warning, which does not prevent the modifier from being applied but which
+ * might need an attention. The message will only be shown in the interface, but will not appear in
+ * the logs. */
+void BKE_modifier_set_warning(const struct Object *ob,
+                              struct ModifierData *md,
+                              const char *format,
+                              ...) ATTR_PRINTF_FORMAT(3, 4);
+
 bool BKE_modifier_is_preview(struct ModifierData *md);
 
 void BKE_modifiers_foreach_ID_link(struct Object *ob, IDWalkFunc walk, void *userData);
@@ -509,7 +519,6 @@ typedef struct CDMaskLink {
  * final_datamask is required at the end of the stack.
  */
 struct CDMaskLink *BKE_modifier_calc_data_masks(const struct Scene *scene,
-                                                struct Object *ob,
                                                 struct ModifierData *md,
                                                 struct CustomData_MeshMasks *final_datamask,
                                                 int required_mode,
@@ -586,12 +595,8 @@ void BKE_modifier_deform_vertsEM(ModifierData *md,
  * e.g. second operand for boolean modifier.
  * Note that modifiers in stack always get fully evaluated COW ID pointers,
  * never original ones. Makes things simpler.
- *
- * \param get_cage_mesh: Return evaluated mesh with only deforming modifiers applied
- * (i.e. mesh topology remains the same as original one, a.k.a. 'cage' mesh).
  */
-struct Mesh *BKE_modifier_get_evaluated_mesh_from_evaluated_object(struct Object *ob_eval,
-                                                                   bool get_cage_mesh);
+struct Mesh *BKE_modifier_get_evaluated_mesh_from_evaluated_object(struct Object *ob_eval);
 
 void BKE_modifier_check_uuids_unique_and_report(const struct Object *object);
 
diff --git a/source/blender/blenkernel/BKE_nla.h b/source/blender/blenkernel/BKE_nla.h
index 2613f4286f0..9d3000759ab 100644
--- a/source/blender/blenkernel/BKE_nla.h
+++ b/source/blender/blenkernel/BKE_nla.h
@@ -7,7 +7,7 @@
  * \ingroup bke
  */
 
-/* temp constant defined for these funcs only... */
+/** Temp constant defined for these functions only. */
 #define NLASTRIP_MIN_LEN_THRESH 0.1f
 
 #ifdef __cplusplus
diff --git a/source/blender/blenkernel/BKE_node.h b/source/blender/blenkernel/BKE_node.h
index b7962ade312..f504d5d1384 100644
--- a/source/blender/blenkernel/BKE_node.h
+++ b/source/blender/blenkernel/BKE_node.h
@@ -101,6 +101,7 @@ typedef struct bNodeSocketTemplate {
 namespace blender {
 class CPPType;
 namespace nodes {
+class DNode;
 class NodeMultiFunctionBuilder;
 class GeoNodeExecParams;
 class NodeDeclarationBuilder;
@@ -109,6 +110,11 @@ class GatherLinkSearchOpParams;
 namespace fn {
 class MFDataType;
 }  // namespace fn
+namespace realtime_compositor {
+class Context;
+class NodeOperation;
+class ShaderNode;
+}  // namespace realtime_compositor
 }  // namespace blender
 
 using CPPTypeHandle = blender::CPPType;
@@ -123,7 +129,14 @@ using SocketGetGeometryNodesCPPValueFunction = void (*)(const struct bNodeSocket
 using NodeGatherSocketLinkOperationsFunction =
     void (*)(blender::nodes::GatherLinkSearchOpParams ¶ms);
 
+using NodeGetCompositorOperationFunction = blender::realtime_compositor::NodeOperation
+    *(*)(blender::realtime_compositor::Context &context, blender::nodes::DNode node);
+using NodeGetCompositorShaderNodeFunction =
+    blender::realtime_compositor::ShaderNode *(*)(blender::nodes::DNode node);
+
 #else
+typedef void *NodeGetCompositorOperationFunction;
+typedef void *NodeGetCompositorShaderNodeFunction;
 typedef void *NodeMultiFunctionBuildFunction;
 typedef void *NodeGeometryExecFunction;
 typedef void *NodeDeclareFunction;
@@ -309,11 +322,23 @@ typedef struct bNodeType {
   /* gpu */
   NodeGPUExecFunction gpu_fn;
 
+  /* Get an instance of this node's compositor operation. Freeing the instance is the
+   * responsibility of the caller. */
+  NodeGetCompositorOperationFunction get_compositor_operation;
+
+  /* Get an instance of this node's compositor shader node. Freeing the instance is the
+   * responsibility of the caller. */
+  NodeGetCompositorShaderNodeFunction get_compositor_shader_node;
+
   /* Build a multi-function for this node. */
   NodeMultiFunctionBuildFunction build_multi_function;
 
   /* Execute a geometry node. */
   NodeGeometryExecFunction geometry_node_execute;
+  /**
+   * If true, the geometry nodes evaluator can call the execute function multiple times to improve
+   * performance by specifying required data in one call and using it for calculations in another.
+   */
   bool geometry_node_execute_supports_laziness;
 
   /* Declares which sockets the node has. */
@@ -370,6 +395,9 @@ typedef struct bNodeTreeType {
   int type;        /* type identifier */
   char idname[64]; /* identifier name */
 
+  /* The ID name of group nodes for this type. */
+  char group_idname[64];
+
   char ui_name[64];
   char ui_description[256];
   int ui_icon;
@@ -444,7 +472,12 @@ void ntreeSetTypes(const struct bContext *C, struct bNodeTree *ntree);
 
 struct bNodeTree *ntreeAddTree(struct Main *bmain, const char *name, const char *idname);
 
-/* copy/free funcs, need to manage ID users */
+struct bNodeTree *ntreeAddTreeEmbedded(struct Main *bmain,
+                                       struct ID *owner_id,
+                                       const char *name,
+                                       const char *idname);
+
+/* Copy/free functions, need to manage ID users. */
 
 /**
  * Free (or release) any data used by this node-tree.
@@ -512,7 +545,9 @@ void ntreeBlendWrite(struct BlendWriter *writer, struct bNodeTree *ntree);
 /**
  * \note `ntree` itself has been read!
  */
-void ntreeBlendReadData(struct BlendDataReader *reader, struct bNodeTree *ntree);
+void ntreeBlendReadData(struct BlendDataReader *reader,
+                        struct ID *owner_id,
+                        struct bNodeTree *ntree);
 void ntreeBlendReadLib(struct BlendLibReader *reader, struct bNodeTree *ntree);
 void ntreeBlendReadExpand(struct BlendExpander *expander, struct bNodeTree *ntree);
 
@@ -679,7 +714,10 @@ struct bNodeLink *nodeAddLink(struct bNodeTree *ntree,
                               struct bNodeSocket *tosock);
 void nodeRemLink(struct bNodeTree *ntree, struct bNodeLink *link);
 void nodeRemSocketLinks(struct bNodeTree *ntree, struct bNodeSocket *sock);
-void nodeMuteLinkToggle(struct bNodeTree *ntree, struct bNodeLink *link);
+/**
+ * Set the mute status of a single link.
+ */
+void nodeLinkSetMute(struct bNodeTree *ntree, struct bNodeLink *link, const bool muted);
 bool nodeLinkIsHidden(const struct bNodeLink *link);
 bool nodeLinkIsSelected(const struct bNodeLink *link);
 void nodeInternalRelink(struct bNodeTree *ntree, struct bNode *node);
@@ -922,8 +960,8 @@ void nodeLabel(const struct bNodeTree *ntree, const struct bNode *node, char *la
  */
 const char *nodeSocketLabel(const struct bNodeSocket *sock);
 
-bool nodeGroupPoll(struct bNodeTree *nodetree,
-                   struct bNodeTree *grouptree,
+bool nodeGroupPoll(const struct bNodeTree *nodetree,
+                   const struct bNodeTree *grouptree,
                    const char **r_disabled_hint);
 
 /**
@@ -1074,7 +1112,7 @@ void BKE_nodetree_remove_layer_n(struct bNodeTree *ntree, struct Scene *scene, i
 //#define SH_NODE_MATERIAL  100
 #define SH_NODE_RGB 101
 #define SH_NODE_VALUE 102
-#define SH_NODE_MIX_RGB 103
+#define SH_NODE_MIX_RGB_LEGACY 103
 #define SH_NODE_VALTORGB 104
 #define SH_NODE_RGBTOBW 105
 #define SH_NODE_SHADERTORGB 106
@@ -1177,6 +1215,7 @@ void BKE_nodetree_remove_layer_n(struct bNodeTree *ntree, struct Scene *scene, i
 #define SH_NODE_POINT_INFO 710
 #define SH_NODE_COMBINE_COLOR 711
 #define SH_NODE_SEPARATE_COLOR 712
+#define SH_NODE_MIX 713
 
 /** \} */
 
@@ -1298,25 +1337,6 @@ void BKE_nodetree_remove_layer_n(struct bNodeTree *ntree, struct Scene *scene, i
 #define CMP_CHAN_RGB 1
 #define CMP_CHAN_A 2
 
-/* filter types */
-#define CMP_FILT_SOFT 0
-#define CMP_FILT_SHARP_BOX 1
-#define CMP_FILT_LAPLACE 2
-#define CMP_FILT_SOBEL 3
-#define CMP_FILT_PREWITT 4
-#define CMP_FILT_KIRSCH 5
-#define CMP_FILT_SHADOW 6
-#define CMP_FILT_SHARP_DIAMOND 7
-
-/* scale node type, in custom1 */
-#define CMP_SCALE_RELATIVE 0
-#define CMP_SCALE_ABSOLUTE 1
-#define CMP_SCALE_SCENEPERCENT 2
-#define CMP_SCALE_RENDERPERCENT 3
-/* custom2 */
-#define CMP_SCALE_RENDERSIZE_FRAME_ASPECT (1 << 0)
-#define CMP_SCALE_RENDERSIZE_FRAME_CROP (1 << 1)
-
 /* track position node, in custom1 */
 #define CMP_TRACKPOS_ABSOLUTE 0
 #define CMP_TRACKPOS_RELATIVE_START 1
@@ -1497,11 +1517,16 @@ struct TexResult;
 #define GEO_NODE_INPUT_INSTANCE_SCALE 1160
 #define GEO_NODE_VOLUME_CUBE 1161
 #define GEO_NODE_POINTS 1162
-#define GEO_NODE_FIELD_ON_DOMAIN 1163
+#define GEO_NODE_INTERPOLATE_DOMAIN 1163
 #define GEO_NODE_MESH_TO_VOLUME 1164
 #define GEO_NODE_UV_UNWRAP 1165
 #define GEO_NODE_UV_PACK_ISLANDS 1166
 #define GEO_NODE_DEFORM_CURVES_ON_SURFACE 1167
+#define GEO_NODE_INPUT_SHORTEST_EDGE_PATHS 1168
+#define GEO_NODE_EDGE_PATHS_TO_CURVES 1169
+#define GEO_NODE_EDGE_PATHS_TO_SELECTION 1170
+#define GEO_NODE_MESH_FACE_SET_BOUNDARIES 1171
+#define GEO_NODE_DISTRIBUTE_POINTS_IN_VOLUME 1172
 
 /** \} */
 
diff --git a/source/blender/blenkernel/BKE_node_runtime.hh b/source/blender/blenkernel/BKE_node_runtime.hh
index f5fb53f962b..65c801a087b 100644
--- a/source/blender/blenkernel/BKE_node_runtime.hh
+++ b/source/blender/blenkernel/BKE_node_runtime.hh
@@ -3,13 +3,25 @@
 #pragma once
 
 #include 
+#include 
 
-#include "BLI_sys_types.h"
+#include "BLI_multi_value_map.hh"
 #include "BLI_utility_mixins.hh"
+#include "BLI_vector.hh"
+
+#include "DNA_node_types.h"
+
+#include "BKE_node.h"
+
+struct bNode;
+struct bNodeSocket;
+struct bNodeTree;
+struct bNodeType;
 
 namespace blender::nodes {
 struct FieldInferencingInterface;
 class NodeDeclaration;
+struct GeometryNodesLazyFunctionGraphInfo;
 }  // namespace blender::nodes
 
 namespace blender::bke {
@@ -36,6 +48,42 @@ class bNodeTreeRuntime : NonCopyable, NonMovable {
 
   /** Information about how inputs and outputs of the node group interact with fields. */
   std::unique_ptr field_inferencing_interface;
+
+  /**
+   * For geometry nodes, a lazy function graph with some additional info is cached. This is used to
+   * evaluate the node group. Caching it here allows us to reuse the preprocessed node tree in case
+   * its used multiple times.
+   */
+  std::mutex geometry_nodes_lazy_function_graph_info_mutex;
+  std::unique_ptr
+      geometry_nodes_lazy_function_graph_info;
+
+  /**
+   * Protects access to all topology cache variables below. This is necessary so that the cache can
+   * be updated on a const #bNodeTree.
+   */
+  std::mutex topology_cache_mutex;
+  bool topology_cache_is_dirty = true;
+  bool topology_cache_exists = false;
+  /**
+   * Under some circumstances, it can be useful to use the cached data while editing the
+   * #bNodeTree. By default, this is protected against using an assert.
+   */
+  mutable std::atomic allow_use_dirty_topology_cache = 0;
+
+  /** Only valid when #topology_cache_is_dirty is false. */
+  Vector nodes;
+  Vector links;
+  Vector sockets;
+  Vector input_sockets;
+  Vector output_sockets;
+  MultiValueMap nodes_by_type;
+  Vector toposort_left_to_right;
+  Vector toposort_right_to_left;
+  Vector group_nodes;
+  bool has_available_link_cycle = false;
+  bool has_undefined_nodes_or_sockets = false;
+  bNode *group_output_node = nullptr;
 };
 
 /**
@@ -47,12 +95,24 @@ class bNodeSocketRuntime : NonCopyable, NonMovable {
  public:
   /**
    * References a socket declaration that is owned by `node->declaration`. This is only runtime
-   * data. It has to be updated when the node declaration changes.
+   * data. It has to be updated when the node declaration changes. Access can be allowed by using
+   * #AllowUsingOutdatedInfo.
    */
   const SocketDeclarationHandle *declaration = nullptr;
 
   /** #eNodeTreeChangedFlag. */
   uint32_t changed_flag = 0;
+
+  /** Only valid when #topology_cache_is_dirty is false. */
+  Vector directly_linked_links;
+  Vector directly_linked_sockets;
+  Vector logically_linked_sockets;
+  Vector logically_linked_skipped_sockets;
+  bNode *owner_node = nullptr;
+  bNodeSocket *internal_link_input = nullptr;
+  int index_in_node = -1;
+  int index_in_all_sockets = -1;
+  int index_in_inout_sockets = -1;
 };
 
 /**
@@ -84,6 +144,428 @@ class bNodeRuntime : NonCopyable, NonMovable {
 
   /** #eNodeTreeChangedFlag. */
   uint32_t changed_flag = 0;
+
+  /** Only valid if #topology_cache_is_dirty is false. */
+  Vector inputs;
+  Vector outputs;
+  Vector internal_links;
+  Map inputs_by_identifier;
+  Map outputs_by_identifier;
+  int index_in_tree = -1;
+  bool has_available_linked_inputs = false;
+  bool has_available_linked_outputs = false;
+  bNodeTree *owner_tree = nullptr;
+};
+
+namespace node_tree_runtime {
+
+/**
+ * Is executed when the node tree changed in the depsgraph.
+ */
+void preprocess_geometry_node_tree_for_evaluation(bNodeTree &tree_cow);
+
+class AllowUsingOutdatedInfo : NonCopyable, NonMovable {
+ private:
+  const bNodeTree &tree_;
+
+ public:
+  AllowUsingOutdatedInfo(const bNodeTree &tree) : tree_(tree)
+  {
+    tree_.runtime->allow_use_dirty_topology_cache.fetch_add(1);
+  }
+
+  ~AllowUsingOutdatedInfo()
+  {
+    tree_.runtime->allow_use_dirty_topology_cache.fetch_sub(1);
+  }
 };
 
+inline bool topology_cache_is_available(const bNodeTree &tree)
+{
+  if (!tree.runtime->topology_cache_exists) {
+    return false;
+  }
+  if (tree.runtime->allow_use_dirty_topology_cache.load() > 0) {
+    return true;
+  }
+  if (tree.runtime->topology_cache_is_dirty) {
+    return false;
+  }
+  return true;
+}
+
+inline bool topology_cache_is_available(const bNode &node)
+{
+  const bNodeTree *ntree = node.runtime->owner_tree;
+  if (ntree == nullptr) {
+    return false;
+  }
+  return topology_cache_is_available(*ntree);
+}
+
+inline bool topology_cache_is_available(const bNodeSocket &socket)
+{
+  const bNode *node = socket.runtime->owner_node;
+  if (node == nullptr) {
+    return false;
+  }
+  return topology_cache_is_available(*node);
+}
+
+}  // namespace node_tree_runtime
+
 }  // namespace blender::bke
+
+/* -------------------------------------------------------------------- */
+/** \name #bNodeTree Inline Methods
+ * \{ */
+
+inline blender::Span bNodeTree::nodes_by_type(const blender::StringRefNull type_idname)
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->nodes_by_type.lookup(nodeTypeFind(type_idname.c_str()));
+}
+
+inline blender::Span bNodeTree::nodes_by_type(
+    const blender::StringRefNull type_idname) const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->nodes_by_type.lookup(nodeTypeFind(type_idname.c_str()));
+}
+
+inline blender::Span bNodeTree::toposort_left_to_right() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->toposort_left_to_right;
+}
+
+inline blender::Span bNodeTree::toposort_right_to_left() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->toposort_right_to_left;
+}
+
+inline blender::Span bNodeTree::all_nodes() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->nodes;
+}
+
+inline blender::Span bNodeTree::all_nodes()
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->nodes;
+}
+
+inline blender::Span bNodeTree::group_nodes() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->group_nodes;
+}
+
+inline blender::Span bNodeTree::group_nodes()
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->group_nodes;
+}
+
+inline bool bNodeTree::has_available_link_cycle() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->has_available_link_cycle;
+}
+
+inline bool bNodeTree::has_undefined_nodes_or_sockets() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->has_undefined_nodes_or_sockets;
+}
+
+inline const bNode *bNodeTree::group_output_node() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->group_output_node;
+}
+
+inline blender::Span bNodeTree::all_input_sockets() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->input_sockets;
+}
+
+inline blender::Span bNodeTree::all_input_sockets()
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->input_sockets;
+}
+
+inline blender::Span bNodeTree::all_output_sockets() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->output_sockets;
+}
+
+inline blender::Span bNodeTree::all_output_sockets()
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->output_sockets;
+}
+
+inline blender::Span bNodeTree::all_sockets() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->sockets;
+}
+
+inline blender::Span bNodeTree::all_sockets()
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->sockets;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name #bNode Inline Methods
+ * \{ */
+
+inline blender::Span bNode::input_sockets()
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->inputs;
+}
+
+inline blender::Span bNode::output_sockets()
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->outputs;
+}
+
+inline blender::Span bNode::input_sockets() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->inputs;
+}
+
+inline blender::Span bNode::output_sockets() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->outputs;
+}
+
+inline bNodeSocket &bNode::input_socket(int index)
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return *this->runtime->inputs[index];
+}
+
+inline bNodeSocket &bNode::output_socket(int index)
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return *this->runtime->outputs[index];
+}
+
+inline const bNodeSocket &bNode::input_socket(int index) const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return *this->runtime->inputs[index];
+}
+
+inline const bNodeSocket &bNode::output_socket(int index) const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return *this->runtime->outputs[index];
+}
+
+inline const bNodeSocket &bNode::input_by_identifier(blender::StringRef identifier) const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return *this->runtime->inputs_by_identifier.lookup_as(identifier);
+}
+
+inline const bNodeSocket &bNode::output_by_identifier(blender::StringRef identifier) const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return *this->runtime->outputs_by_identifier.lookup_as(identifier);
+}
+
+inline const bNodeTree &bNode::owner_tree() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return *this->runtime->owner_tree;
+}
+
+inline blender::StringRefNull bNode::label_or_name() const
+{
+  if (this->label[0] == '\0') {
+    return this->name;
+  }
+  return this->label;
+}
+
+inline bool bNode::is_muted() const
+{
+  return this->flag & NODE_MUTED;
+}
+
+inline bool bNode::is_reroute() const
+{
+  return this->type == NODE_REROUTE;
+}
+
+inline bool bNode::is_frame() const
+{
+  return this->type == NODE_FRAME;
+}
+
+inline bool bNode::is_group() const
+{
+  return ELEM(this->type, NODE_GROUP, NODE_CUSTOM_GROUP);
+}
+
+inline bool bNode::is_group_input() const
+{
+  return this->type == NODE_GROUP_INPUT;
+}
+
+inline bool bNode::is_group_output() const
+{
+  return this->type == NODE_GROUP_OUTPUT;
+}
+
+inline blender::Span bNode::internal_links_span() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->internal_links;
+}
+
+inline const blender::nodes::NodeDeclaration *bNode::declaration() const
+{
+  return this->runtime->declaration;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name #bNodeLink Inline Methods
+ * \{ */
+
+inline bool bNodeLink::is_muted() const
+{
+  return this->flag & NODE_LINK_MUTED;
+}
+
+inline bool bNodeLink::is_available() const
+{
+  return this->fromsock->is_available() && this->tosock->is_available();
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name #bNodeSocket Inline Methods
+ * \{ */
+
+inline int bNodeSocket::index() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->index_in_node;
+}
+
+inline int bNodeSocket::index_in_tree() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->index_in_all_sockets;
+}
+
+inline bool bNodeSocket::is_available() const
+{
+  return (this->flag & SOCK_UNAVAIL) == 0;
+}
+
+inline bNode &bNodeSocket::owner_node()
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return *this->runtime->owner_node;
+}
+
+inline const bNodeTree &bNodeSocket::owner_tree() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return *this->runtime->owner_node->runtime->owner_tree;
+}
+
+inline blender::Span bNodeSocket::logically_linked_sockets() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->logically_linked_sockets;
+}
+
+inline blender::Span bNodeSocket::directly_linked_links() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->directly_linked_links;
+}
+
+inline blender::Span bNodeSocket::directly_linked_links()
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->directly_linked_links;
+}
+
+inline blender::Span bNodeSocket::directly_linked_sockets() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->directly_linked_sockets;
+}
+
+inline blender::Span bNodeSocket::directly_linked_sockets()
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return this->runtime->directly_linked_sockets;
+}
+
+inline bool bNodeSocket::is_directly_linked() const
+{
+  return !this->directly_linked_links().is_empty();
+}
+
+inline bool bNodeSocket::is_logically_linked() const
+{
+  return !this->logically_linked_sockets().is_empty();
+}
+
+inline const bNodeSocket *bNodeSocket::internal_link_input() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  BLI_assert(this->in_out == SOCK_OUT);
+  return this->runtime->internal_link_input;
+}
+
+template const T *bNodeSocket::default_value_typed() const
+{
+  return static_cast(this->default_value);
+}
+
+inline bool bNodeSocket::is_input() const
+{
+  return this->in_out == SOCK_IN;
+}
+
+inline bool bNodeSocket::is_output() const
+{
+  return this->in_out == SOCK_OUT;
+}
+
+inline bool bNodeSocket::is_multi_input() const
+{
+  return this->flag & SOCK_MULTI_INPUT;
+}
+
+inline const bNode &bNodeSocket::owner_node() const
+{
+  BLI_assert(blender::bke::node_tree_runtime::topology_cache_is_available(*this));
+  return *this->runtime->owner_node;
+}
+
+/** \} */
diff --git a/source/blender/blenkernel/BKE_node_tree_update.h b/source/blender/blenkernel/BKE_node_tree_update.h
index 5e377728bb7..801ba22b3e9 100644
--- a/source/blender/blenkernel/BKE_node_tree_update.h
+++ b/source/blender/blenkernel/BKE_node_tree_update.h
@@ -33,6 +33,7 @@ void BKE_ntree_update_tag_all(struct bNodeTree *ntree);
 void BKE_ntree_update_tag_node_property(struct bNodeTree *ntree, struct bNode *node);
 void BKE_ntree_update_tag_node_new(struct bNodeTree *ntree, struct bNode *node);
 void BKE_ntree_update_tag_node_removed(struct bNodeTree *ntree);
+void BKE_ntree_update_tag_node_reordered(struct bNodeTree *ntree);
 void BKE_ntree_update_tag_node_mute(struct bNodeTree *ntree, struct bNode *node);
 void BKE_ntree_update_tag_node_internal_link(struct bNodeTree *ntree, struct bNode *node);
 
diff --git a/source/blender/blenkernel/BKE_object.h b/source/blender/blenkernel/BKE_object.h
index f0eb16a819d..60dfc0af25f 100644
--- a/source/blender/blenkernel/BKE_object.h
+++ b/source/blender/blenkernel/BKE_object.h
@@ -175,9 +175,10 @@ struct Object *BKE_object_add_only_object(struct Main *bmain,
  * \note Creates minimum required data, but without vertices etc.
  */
 struct Object *BKE_object_add(struct Main *bmain,
+                              struct Scene *scene,
                               struct ViewLayer *view_layer,
                               int type,
-                              const char *name) ATTR_NONNULL(1, 2) ATTR_RETURNS_NONNULL;
+                              const char *name) ATTR_NONNULL(1, 2, 3) ATTR_RETURNS_NONNULL;
 /**
  * Add a new object, using another one as a reference
  *
@@ -200,6 +201,7 @@ struct Object *BKE_object_add_from(struct Main *bmain,
  * assigning it to the object.
  */
 struct Object *BKE_object_add_for_data(struct Main *bmain,
+                                       const struct Scene *scene,
                                        struct ViewLayer *view_layer,
                                        int type,
                                        const char *name,
@@ -283,31 +285,38 @@ void BKE_object_matrix_local_get(struct Object *ob, float r_mat[4][4]);
 bool BKE_object_pose_context_check(const struct Object *ob);
 struct Object *BKE_object_pose_armature_get(struct Object *ob);
 struct Object *BKE_object_pose_armature_get_visible(struct Object *ob,
+                                                    const struct Scene *scene,
                                                     struct ViewLayer *view_layer,
                                                     struct View3D *v3d);
 
 /**
  * Access pose array with special check to get pose object when in weight paint mode.
  */
-struct Object **BKE_object_pose_array_get_ex(struct ViewLayer *view_layer,
+struct Object **BKE_object_pose_array_get_ex(const struct Scene *scene,
+                                             struct ViewLayer *view_layer,
                                              struct View3D *v3d,
                                              unsigned int *r_objects_len,
                                              bool unique);
-struct Object **BKE_object_pose_array_get_unique(struct ViewLayer *view_layer,
+struct Object **BKE_object_pose_array_get_unique(const struct Scene *scene,
+                                                 struct ViewLayer *view_layer,
                                                  struct View3D *v3d,
                                                  unsigned int *r_objects_len);
-struct Object **BKE_object_pose_array_get(struct ViewLayer *view_layer,
+struct Object **BKE_object_pose_array_get(const struct Scene *scene,
+                                          struct ViewLayer *view_layer,
                                           struct View3D *v3d,
                                           unsigned int *r_objects_len);
 
-struct Base **BKE_object_pose_base_array_get_ex(struct ViewLayer *view_layer,
+struct Base **BKE_object_pose_base_array_get_ex(const struct Scene *scene,
+                                                struct ViewLayer *view_layer,
                                                 struct View3D *v3d,
                                                 unsigned int *r_bases_len,
                                                 bool unique);
-struct Base **BKE_object_pose_base_array_get_unique(struct ViewLayer *view_layer,
+struct Base **BKE_object_pose_base_array_get_unique(const struct Scene *scene,
+                                                    struct ViewLayer *view_layer,
                                                     struct View3D *v3d,
                                                     unsigned int *r_bases_len);
-struct Base **BKE_object_pose_base_array_get(struct ViewLayer *view_layer,
+struct Base **BKE_object_pose_base_array_get(const struct Scene *scene,
+                                             struct ViewLayer *view_layer,
                                              struct View3D *v3d,
                                              unsigned int *r_bases_len);
 
@@ -474,8 +483,8 @@ void BKE_object_handle_data_update(struct Depsgraph *depsgraph,
  */
 void BKE_object_handle_update(struct Depsgraph *depsgraph, struct Scene *scene, struct Object *ob);
 /**
- * The main object update call, for object matrix, constraints, keys and #DispList (modifiers)
- * requires flags to be set!
+ * The main object update call, for object matrix, constraints, keys and modifiers.
+ * Requires flags to be set!
  *
  * Ideally we shouldn't have to pass the rigid body world,
  * but need bigger restructuring to avoid id.
@@ -586,7 +595,6 @@ void BKE_object_runtime_reset_on_copy(struct Object *object, int flag);
 void BKE_object_runtime_free_data(struct Object *object);
 
 void BKE_object_batch_cache_dirty_tag(struct Object *ob);
-void BKE_object_data_batch_cache_dirty_tag(struct ID *object_data);
 
 /* this function returns a superset of the scenes selection based on relationships */
 
@@ -613,7 +621,8 @@ typedef enum eObjectSet {
  * If #OB_SET_VISIBLE or#OB_SET_SELECTED are collected,
  * then also add related objects according to the given \a includeFilter.
  */
-struct LinkNode *BKE_object_relational_superset(struct ViewLayer *view_layer,
+struct LinkNode *BKE_object_relational_superset(const struct Scene *scene,
+                                                struct ViewLayer *view_layer,
                                                 eObjectSet objectSet,
                                                 eObRelationTypes includeFilter);
 /**
diff --git a/source/blender/blenkernel/BKE_outliner_treehash.h b/source/blender/blenkernel/BKE_outliner_treehash.h
deleted file mode 100644
index 6f4d126fcbf..00000000000
--- a/source/blender/blenkernel/BKE_outliner_treehash.h
+++ /dev/null
@@ -1,46 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-#pragma once
-
-/** \file
- * \ingroup bke
- */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-struct BLI_mempool;
-struct ID;
-struct TreeStoreElem;
-
-/* create and fill hashtable with treestore elements */
-void *BKE_outliner_treehash_create_from_treestore(struct BLI_mempool *treestore);
-
-/* full rebuild for already allocated hashtable */
-void *BKE_outliner_treehash_rebuild_from_treestore(void *treehash, struct BLI_mempool *treestore);
-
-/* clear element usage flags */
-void BKE_outliner_treehash_clear_used(void *treehash);
-
-/* Add/remove hashtable elements */
-void BKE_outliner_treehash_add_element(void *treehash, struct TreeStoreElem *elem);
-void BKE_outliner_treehash_remove_element(void *treehash, struct TreeStoreElem *elem);
-
-/* find first unused element with specific type, nr and id */
-struct TreeStoreElem *BKE_outliner_treehash_lookup_unused(void *treehash,
-                                                          short type,
-                                                          short nr,
-                                                          struct ID *id);
-
-/* find user or unused element with specific type, nr and id */
-struct TreeStoreElem *BKE_outliner_treehash_lookup_any(void *treehash,
-                                                       short type,
-                                                       short nr,
-                                                       struct ID *id);
-
-/* free treehash structure */
-void BKE_outliner_treehash_free(void *treehash);
-
-#ifdef __cplusplus
-}
-#endif
diff --git a/source/blender/blenkernel/BKE_outliner_treehash.hh b/source/blender/blenkernel/BKE_outliner_treehash.hh
new file mode 100644
index 00000000000..7f1dad5fd68
--- /dev/null
+++ b/source/blender/blenkernel/BKE_outliner_treehash.hh
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#pragma once
+
+/** \file
+ * \ingroup bke
+ *
+ * Hash table of tree-store elements (#TreeStoreElem) for fast lookups via a (id, type, index)
+ * tuple as key.
+ *
+ * The Outliner may have to perform many lookups for rebuilding complex trees, so this should be
+ * treated as performance sensitive.
+ */
+
+#include 
+
+#include "BLI_map.hh"
+
+struct BLI_mempool;
+struct ID;
+struct TreeStoreElem;
+
+namespace blender::bke::outliner::treehash {
+
+/* -------------------------------------------------------------------- */
+
+class TreeStoreElemKey {
+ public:
+  ID *id = nullptr;
+  short type = 0;
+  short nr = 0;
+
+  explicit TreeStoreElemKey(const TreeStoreElem &elem);
+  TreeStoreElemKey(ID *id, short type, short nr);
+
+  uint64_t hash() const;
+  friend bool operator==(const TreeStoreElemKey &a, const TreeStoreElemKey &b);
+};
+
+/* -------------------------------------------------------------------- */
+
+class TreeHash {
+  Map> elem_groups_;
+
+ public:
+  ~TreeHash();
+
+  /** Create and fill hash-table with treestore elements */
+  static std::unique_ptr create_from_treestore(BLI_mempool &treestore);
+
+  /** Full rebuild for already allocated hash-table. */
+  void rebuild_from_treestore(BLI_mempool &treestore);
+
+  /** Clear element usage flags. */
+  void clear_used();
+
+  /** Add hash-table element. */
+  void add_element(TreeStoreElem &elem);
+  /** Remove hash-table element. */
+  void remove_element(TreeStoreElem &elem);
+
+  /** Find first unused element with specific type, nr and id. */
+  TreeStoreElem *lookup_unused(short type, short nr, ID *id) const;
+
+  /** Find user or unused element with specific type, nr and id. */
+  TreeStoreElem *lookup_any(short type, short nr, ID *id) const;
+
+ private:
+  TreeHash() = default;
+
+  TseGroup *lookup_group(const TreeStoreElemKey &key) const;
+  TseGroup *lookup_group(const TreeStoreElem &elem) const;
+  TseGroup *lookup_group(short type, short nr, ID *id) const;
+  void fill_treehash(BLI_mempool &treestore);
+};
+
+}  // namespace blender::bke::outliner::treehash
diff --git a/source/blender/blenkernel/BKE_paint.h b/source/blender/blenkernel/BKE_paint.h
index ffe80ff47b6..ed0969a6306 100644
--- a/source/blender/blenkernel/BKE_paint.h
+++ b/source/blender/blenkernel/BKE_paint.h
@@ -8,11 +8,14 @@
  */
 
 #include "BLI_bitmap.h"
+#include "BLI_compiler_compat.h"
 #include "BLI_utildefines.h"
+
 #include "DNA_brush_enums.h"
 #include "DNA_object_enums.h"
 
 #include "BKE_attribute.h"
+#include "BKE_pbvh.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -59,10 +62,10 @@ struct bContext;
 struct bToolRef;
 struct tPaletteColorHSV;
 
-extern const char PAINT_CURSOR_SCULPT[3];
-extern const char PAINT_CURSOR_VERTEX_PAINT[3];
-extern const char PAINT_CURSOR_WEIGHT_PAINT[3];
-extern const char PAINT_CURSOR_TEXTURE_PAINT[3];
+extern const uchar PAINT_CURSOR_SCULPT[3];
+extern const uchar PAINT_CURSOR_VERTEX_PAINT[3];
+extern const uchar PAINT_CURSOR_WEIGHT_PAINT[3];
+extern const uchar PAINT_CURSOR_TEXTURE_PAINT[3];
 
 typedef enum ePaintMode {
   PAINT_MODE_SCULPT = 0,
@@ -97,6 +100,7 @@ typedef enum ePaintOverlayControlFlags {
   PAINT_OVERLAY_OVERRIDE_PRIMARY = (1 << 5),
   PAINT_OVERLAY_OVERRIDE_SECONDARY = (1 << 6),
 } ePaintOverlayControlFlags;
+ENUM_OPERATORS(ePaintOverlayControlFlags, PAINT_OVERLAY_OVERRIDE_SECONDARY);
 
 #define PAINT_OVERRIDE_MASK \
   (PAINT_OVERLAY_OVERRIDE_SECONDARY | PAINT_OVERLAY_OVERRIDE_PRIMARY | \
@@ -156,7 +160,7 @@ struct PaintCurve *BKE_paint_curve_add(struct Main *bmain, const char *name);
  * Call when entering each respective paint mode.
  */
 bool BKE_paint_ensure(struct ToolSettings *ts, struct Paint **r_paint);
-void BKE_paint_init(struct Main *bmain, struct Scene *sce, ePaintMode mode, const char col[3]);
+void BKE_paint_init(struct Main *bmain, struct Scene *sce, ePaintMode mode, const uchar col[3]);
 void BKE_paint_free(struct Paint *p);
 /**
  * Called when copying scene settings, so even if 'src' and 'tar' are the same still do a
@@ -200,15 +204,18 @@ bool BKE_paint_select_vert_test(struct Object *ob);
  * (when we don't care if its face or vert)
  */
 bool BKE_paint_select_elem_test(struct Object *ob);
+/**
+ * Checks if face/vertex hiding is always applied in the current mode.
+ * Returns true in vertex/weight paint.
+ */
+bool BKE_paint_always_hide_test(struct Object *ob);
 
 /* Partial visibility. */
 
 /**
  * Returns non-zero if any of the face's vertices are hidden, zero otherwise.
  */
-bool paint_is_face_hidden(const struct MLoopTri *lt,
-                          const struct MVert *mvert,
-                          const struct MLoop *mloop);
+bool paint_is_face_hidden(const struct MLoopTri *lt, const bool *hide_poly);
 /**
  * Returns non-zero if any of the corners of the grid
  * face whose inner corner is at (x, y) are hidden, zero otherwise.
@@ -392,10 +399,10 @@ typedef struct SculptVertexInfo {
 
 typedef struct SculptBoundaryEditInfo {
   /* Vertex index from where the topology propagation reached this vertex. */
-  int original_vertex;
+  int original_vertex_i;
 
   /* How many steps were needed to reach this vertex from the boundary. */
-  int num_propagation_steps;
+  int propagation_steps_num;
 
   /* Strength that is used to deform this vertex. */
   float strength_factor;
@@ -403,15 +410,15 @@ typedef struct SculptBoundaryEditInfo {
 
 /* Edge for drawing the boundary preview in the cursor. */
 typedef struct SculptBoundaryPreviewEdge {
-  int v1;
-  int v2;
+  PBVHVertRef v1;
+  PBVHVertRef v2;
 } SculptBoundaryPreviewEdge;
 
 typedef struct SculptBoundary {
   /* Vertex indices of the active boundary. */
-  int *vertices;
-  int vertices_capacity;
-  int num_vertices;
+  PBVHVertRef *verts;
+  int verts_capacity;
+  int verts_num;
 
   /* Distance from a vertex in the boundary to initial vertex indexed by vertex index, taking into
    * account the length of all edges between them. Any vertex that is not in the boundary will have
@@ -421,18 +428,19 @@ typedef struct SculptBoundary {
   /* Data for drawing the preview. */
   SculptBoundaryPreviewEdge *edges;
   int edges_capacity;
-  int num_edges;
+  int edges_num;
 
   /* True if the boundary loops into itself. */
   bool forms_loop;
 
   /* Initial vertex in the boundary which is closest to the current sculpt active vertex. */
-  int initial_vertex;
+  PBVHVertRef initial_vertex;
+  int initial_vertex_i;
 
   /* Vertex that at max_propagation_steps from the boundary and closest to the original active
    * vertex that was used to initialize the boundary. This is used as a reference to check how much
    * the deformation will go into the mesh and to calculate the strength of the brushes. */
-  int pivot_vertex;
+  PBVHVertRef pivot_vertex;
 
   /* Stores the initial positions of the pivot and boundary initial vertex as they may be deformed
    * during the brush action. This allows to use them as a reference positions and vectors for some
@@ -478,6 +486,74 @@ typedef struct SculptFakeNeighbors {
 
 /* Session data (mode-specific) */
 
+/* Custom Temporary Attributes */
+
+typedef struct SculptAttributeParams {
+  /* Allocate a flat array outside the CustomData system.  Cannot be combined with permanent. */
+  int simple_array : 1;
+
+  /* Do not mark CustomData layer as temporary.  Cannot be combined with simple_array.  Doesn't
+   * work with PBVH_GRIDS.
+   */
+  int permanent : 1;   /* Cannot be combined with simple_array. */
+  int stroke_only : 1; /* Release layer at end of struct */
+} SculptAttributeParams;
+
+typedef struct SculptAttribute {
+  /* Domain, data type and name */
+  eAttrDomain domain;
+  eCustomDataType proptype;
+  char name[MAX_CUSTOMDATA_LAYER_NAME];
+
+  /* Source layer on mesh/bmesh, if any. */
+  struct CustomDataLayer *layer;
+
+  /* Data stored as flat array. */
+  void *data;
+  int elem_size, elem_num;
+  bool data_for_bmesh; /* Temporary data store as array outside of bmesh. */
+
+  /* Data stored per BMesh element. */
+  int bmesh_cd_offset;
+
+  /* Sculpt usage */
+  SculptAttributeParams params;
+
+  /* Used to keep track of which preallocated SculptAttribute instances
+   * inside of SculptSession.temp_attribute are used.
+   */
+  bool used;
+} SculptAttribute;
+
+#define SCULPT_MAX_ATTRIBUTES 64
+
+/* Get a standard attribute name.  Key must match up with a member
+ * of SculptAttributePointers.
+ */
+
+#define SCULPT_ATTRIBUTE_NAME(key) \
+  (offsetof(SculptAttributePointers, key) >= 0 ? /* Spellcheck name. */ \
+       (".sculpt_" #key)                         /* Make name. */ \
+       : \
+       "You misspelled the layer name key")
+
+/* Convenience pointers for standard sculpt attributes. */
+
+typedef struct SculptAttributePointers {
+  /* Persistent base. */
+  SculptAttribute *persistent_co;
+  SculptAttribute *persistent_no;
+  SculptAttribute *persistent_disp;
+
+  /* Precomputed auto-mask factor indexed by vertex, owned by the auto-masking system and
+   * initialized in #SCULPT_automasking_cache_init when needed. */
+  SculptAttribute *automasking_factor;
+
+  /* BMesh */
+  SculptAttribute *dyntopo_node_id_vertex;
+  SculptAttribute *dyntopo_node_id_face;
+} SculptAttributePointers;
+
 typedef struct SculptSession {
   /* Mesh data (not copied) can come either directly from a Mesh, or from a MultiresDM */
   struct { /* Special handling for multires meshes */
@@ -491,8 +567,8 @@ typedef struct SculptSession {
 
   /* These are always assigned to base mesh data when using PBVH_FACES and PBVH_GRIDS. */
   struct MVert *mvert;
-  struct MPoly *mpoly;
-  struct MLoop *mloop;
+  const struct MPoly *mpoly;
+  const struct MLoop *mloop;
 
   /* These contain the vertex and poly counts of the final mesh. */
   int totvert, totpoly;
@@ -522,18 +598,20 @@ typedef struct SculptSession {
   /* Mesh Face Sets */
   /* Total number of polys of the base mesh. */
   int totfaces;
-  /* Face sets store its visibility in the sign of the integer, using the absolute value as the
-   * Face Set ID. Positive IDs are visible, negative IDs are hidden.
-   * The 0 ID is not used by the tools or the visibility system, it is just used when creating new
+
+  /* The 0 ID is not used by the tools or the visibility system, it is just used when creating new
    * geometry (the trim tool, for example) to detect which geometry was just added, so it can be
    * assigned a valid Face Set after creation. Tools are not intended to run with Face Sets IDs set
    * to 0. */
   int *face_sets;
+  /**
+   * A reference to the ".hide_poly" attribute, to store whether (base) polygons are hidden.
+   * May be null.
+   */
+  bool *hide_poly;
 
   /* BMesh for dynamic topology sculpting */
   struct BMesh *bm;
-  int cd_vert_node_offset;
-  int cd_face_node_offset;
   bool bm_smooth_shading;
   /* Undo/redo log for dynamic topology sculpting */
   struct BMLog *bm_log;
@@ -560,12 +638,13 @@ typedef struct SculptSession {
   struct ExpandCache *expand_cache;
 
   /* Cursor data and active vertex for tools */
-  int active_vertex_index;
+  PBVHVertRef active_vertex;
 
   int active_face_index;
   int active_grid_index;
 
-  /* When active, the cursor draws with faded colors, indicating that there is an action enabled.
+  /* When active, the cursor draws with faded colors, indicating that there is an action
+   * enabled.
    */
   bool draw_faded_cursor;
   float cursor_radius;
@@ -574,8 +653,10 @@ typedef struct SculptSession {
   float cursor_sampled_normal[3];
   float cursor_view_normal[3];
 
-  /* For Sculpt trimming gesture tools, initial ray-cast data from the position of the mouse when
-   * the gesture starts (intersection with the surface and if they ray hit the surface or not). */
+  /* For Sculpt trimming gesture tools, initial ray-cast data from the position of the mouse
+   * when
+   * the gesture starts (intersection with the surface and if they ray hit the surface or not).
+   */
   float gesture_initial_location[3];
   float gesture_initial_normal[3];
   bool gesture_initial_hit;
@@ -586,8 +667,8 @@ typedef struct SculptSession {
   struct Scene *scene;
 
   /* Dynamic mesh preview */
-  int *preview_vert_index_list;
-  int preview_vert_index_count;
+  PBVHVertRef *preview_vert_list;
+  int preview_vert_count;
 
   /* Pose Brush Preview */
   float pose_origin[3];
@@ -596,10 +677,6 @@ typedef struct SculptSession {
   /* Boundary Brush Preview */
   SculptBoundary *boundary_preview;
 
-  /* Mesh State Persistence */
-  /* This is freed with the PBVH, so it is always in sync with the mesh. */
-  SculptPersistentBase *persistent_base;
-
   SculptVertexInfo vertex_info;
   SculptFakeNeighbors fake_neighbors;
 
@@ -645,6 +722,14 @@ typedef struct SculptSession {
    */
   char needs_flush_to_id;
 
+  /* This is a fixed-size array so we can pass pointers to its elements
+   * to client code. This is important to keep bmesh offsets up to date.
+   */
+  struct SculptAttribute temp_attributes[SCULPT_MAX_ATTRIBUTES];
+
+  /* Convenience #SculptAttribute pointers. */
+  SculptAttributePointers attrs;
+
   /**
    * Some tools follows the shading chosen by the last used tool canvas.
    * When not set the viewport shading color would be used.
@@ -665,6 +750,75 @@ void BKE_sculptsession_free_deformMats(struct SculptSession *ss);
 void BKE_sculptsession_free_vwpaint_data(struct SculptSession *ss);
 void BKE_sculptsession_bm_to_me(struct Object *ob, bool reorder);
 void BKE_sculptsession_bm_to_me_for_render(struct Object *object);
+int BKE_sculptsession_vertex_count(const SculptSession *ss);
+
+/* Ensure an attribute layer exists. */
+SculptAttribute *BKE_sculpt_attribute_ensure(struct Object *ob,
+                                             eAttrDomain domain,
+                                             eCustomDataType proptype,
+                                             const char *name,
+                                             const SculptAttributeParams *params);
+
+/* Returns nullptr if attribute does not exist. */
+SculptAttribute *BKE_sculpt_attribute_get(struct Object *ob,
+                                          eAttrDomain domain,
+                                          eCustomDataType proptype,
+                                          const char *name);
+
+bool BKE_sculpt_attribute_exists(struct Object *ob,
+                                 eAttrDomain domain,
+                                 eCustomDataType proptype,
+                                 const char *name);
+
+bool BKE_sculpt_attribute_destroy(struct Object *ob, SculptAttribute *attr);
+
+/* Destroy all attributes and pseudo-attributes created by sculpt mode. */
+void BKE_sculpt_attribute_destroy_temporary_all(struct Object *ob);
+
+/* Destroy attributes that were marked as stroke only in SculptAttributeParams. */
+void BKE_sculpt_attributes_destroy_temporary_stroke(struct Object *ob);
+
+BLI_INLINE void *BKE_sculpt_vertex_attr_get(const PBVHVertRef vertex, const SculptAttribute *attr)
+{
+  if (attr->data) {
+    char *p = (char *)attr->data;
+    int idx = (int)vertex.i;
+
+    if (attr->data_for_bmesh) {
+      BMElem *v = (BMElem *)vertex.i;
+      idx = v->head.index;
+    }
+
+    return p + attr->elem_size * (int)idx;
+  }
+  else {
+    BMElem *v = (BMElem *)vertex.i;
+    return BM_ELEM_CD_GET_VOID_P(v, attr->bmesh_cd_offset);
+  }
+
+  return NULL;
+}
+
+BLI_INLINE void *BKE_sculpt_face_attr_get(const PBVHFaceRef vertex, const SculptAttribute *attr)
+{
+  if (attr->data) {
+    char *p = (char *)attr->data;
+    int idx = (int)vertex.i;
+
+    if (attr->data_for_bmesh) {
+      BMElem *v = (BMElem *)vertex.i;
+      idx = v->head.index;
+    }
+
+    return p + attr->elem_size * (int)idx;
+  }
+  else {
+    BMElem *v = (BMElem *)vertex.i;
+    return BM_ELEM_CD_GET_VOID_P(v, attr->bmesh_cd_offset);
+  }
+
+  return NULL;
+}
 
 /**
  * Create new color layer on object if it doesn't have one and if experimental feature set has
@@ -680,7 +834,7 @@ void BKE_sculpt_update_object_for_edit(struct Depsgraph *depsgraph,
                                        bool need_pmap,
                                        bool need_mask,
                                        bool is_paint_tool);
-void BKE_sculpt_update_object_before_eval(const struct Scene *scene, struct Object *ob_eval);
+void BKE_sculpt_update_object_before_eval(struct Object *ob_eval);
 void BKE_sculpt_update_object_after_eval(struct Depsgraph *depsgraph, struct Object *ob_eval);
 
 /**
@@ -689,6 +843,13 @@ void BKE_sculpt_update_object_after_eval(struct Depsgraph *depsgraph, struct Obj
  */
 struct MultiresModifierData *BKE_sculpt_multires_active(const struct Scene *scene,
                                                         struct Object *ob);
+int *BKE_sculpt_face_sets_ensure(struct Mesh *mesh);
+/**
+ * Create the attribute used to store face visibility and retrieve its data.
+ * Note that changes to the face visibility have to be propagated to other domains
+ * (see #SCULPT_visibility_sync_all_from_faces).
+ */
+bool *BKE_sculpt_hide_poly_ensure(struct Mesh *mesh);
 int BKE_sculpt_mask_layers_ensure(struct Object *ob, struct MultiresModifierData *mmd);
 void BKE_sculpt_toolsettings_data_ensure(struct Scene *scene);
 
@@ -696,32 +857,8 @@ struct PBVH *BKE_sculpt_object_pbvh_ensure(struct Depsgraph *depsgraph, struct O
 
 void BKE_sculpt_bvh_update_from_ccg(struct PBVH *pbvh, struct SubdivCCG *subdiv_ccg);
 
-/**
- * This ensure that all elements in the mesh (both vertices and grids) have their visibility
- * updated according to the face sets.
- */
-void BKE_sculpt_sync_face_set_visibility(struct Mesh *mesh, struct SubdivCCG *subdiv_ccg);
-
-/**
- * Individual function to sync the Face Set visibility to mesh and grids.
- */
-void BKE_sculpt_sync_face_sets_visibility_to_base_mesh(struct Mesh *mesh);
-void BKE_sculpt_sync_face_sets_visibility_to_grids(struct Mesh *mesh,
-                                                   struct SubdivCCG *subdiv_ccg);
-
-/**
- * Ensures that a Face Set data-layers exists. If it does not, it creates one respecting the
- * visibility stored in the vertices of the mesh. If it does, it copies the visibility from the
- * mesh to the Face Sets. */
-void BKE_sculpt_face_sets_ensure_from_base_mesh_visibility(struct Mesh *mesh);
-
-/**
- * Ensures we do have expected mesh data in original mesh for the sculpt mode.
- *
- * \note IDs are expected to be original ones here, and calling code should ensure it updates its
- * depsgraph properly after calling this function if it needs up-to-date evaluated data.
- */
 void BKE_sculpt_ensure_orig_mesh_data(struct Scene *scene, struct Object *object);
+void BKE_sculpt_sync_face_visibility_to_grids(struct Mesh *mesh, struct SubdivCCG *subdiv_ccg);
 
 /**
  * Test if PBVH can be used directly for drawing, which is faster than
diff --git a/source/blender/blenkernel/BKE_particle.h b/source/blender/blenkernel/BKE_particle.h
index 5f8b2fafdd3..a797aef73f6 100644
--- a/source/blender/blenkernel/BKE_particle.h
+++ b/source/blender/blenkernel/BKE_particle.h
@@ -579,7 +579,7 @@ void psys_get_texture(struct ParticleSimulationData *sim,
  * Interpolate a location on a face based on face coordinates.
  */
 void psys_interpolate_face(struct Mesh *mesh,
-                           struct MVert *mvert,
+                           const struct MVert *mvert,
                            const float (*vert_normals)[3],
                            struct MFace *mface,
                            struct MTFace *tface,
diff --git a/source/blender/blenkernel/BKE_pbvh.h b/source/blender/blenkernel/BKE_pbvh.h
index f517ff3a949..ff2140732cc 100644
--- a/source/blender/blenkernel/BKE_pbvh.h
+++ b/source/blender/blenkernel/BKE_pbvh.h
@@ -8,8 +8,11 @@
  */
 
 #include "BLI_bitmap.h"
+#include "BLI_compiler_compat.h"
 #include "BLI_ghash.h"
 
+#include "bmesh.h"
+
 /* For embedding CCGKey in iterator. */
 #include "BKE_attribute.h"
 #include "BKE_ccg.h"
@@ -43,6 +46,41 @@ struct MeshElemMap;
 typedef struct PBVH PBVH;
 typedef struct PBVHNode PBVHNode;
 
+typedef enum {
+  PBVH_FACES,
+  PBVH_GRIDS,
+  PBVH_BMESH,
+} PBVHType;
+
+/* Public members of PBVH, used for inlined functions. */
+struct PBVHPublic {
+  PBVHType type;
+  BMesh *bm;
+};
+
+/*
+ * These structs represent logical verts/edges/faces.
+ * for PBVH_GRIDS and PBVH_FACES they store integer
+ * offsets, PBVH_BMESH stores pointers.
+ *
+ * The idea is to enforce stronger type checking by encapsulating
+ * intptr_t's in structs.
+ */
+
+typedef struct PBVHVertRef {
+  intptr_t i;
+} PBVHVertRef;
+
+typedef struct PBVHEdgeRef {
+  intptr_t i;
+} PBVHEdgeRef;
+
+typedef struct PBVHFaceRef {
+  intptr_t i;
+} PBVHFaceRef;
+
+#define PBVH_REF_NONE -1LL
+
 typedef struct {
   float (*co)[3];
 } PBVHProxyNode;
@@ -87,9 +125,97 @@ typedef struct PBVHFrustumPlanes {
   int num_planes;
 } PBVHFrustumPlanes;
 
+BLI_INLINE PBVHType BKE_pbvh_type(const PBVH *pbvh)
+{
+  return ((const struct PBVHPublic *)pbvh)->type;
+}
+
+BLI_INLINE BMesh *BKE_pbvh_get_bmesh(PBVH *pbvh)
+{
+  return ((struct PBVHPublic *)pbvh)->bm;
+}
+
 void BKE_pbvh_set_frustum_planes(PBVH *pbvh, PBVHFrustumPlanes *planes);
 void BKE_pbvh_get_frustum_planes(PBVH *pbvh, PBVHFrustumPlanes *planes);
 
+BLI_INLINE PBVHVertRef BKE_pbvh_make_vref(intptr_t i)
+{
+  PBVHVertRef ret = {i};
+  return ret;
+}
+
+BLI_INLINE PBVHEdgeRef BKE_pbvh_make_eref(intptr_t i)
+{
+  PBVHEdgeRef ret = {i};
+  return ret;
+}
+
+BLI_INLINE PBVHFaceRef BKE_pbvh_make_fref(intptr_t i)
+{
+  PBVHFaceRef ret = {i};
+  return ret;
+}
+
+BLI_INLINE int BKE_pbvh_vertex_to_index(PBVH *pbvh, PBVHVertRef v)
+{
+  return (BKE_pbvh_type(pbvh) == PBVH_BMESH && v.i != PBVH_REF_NONE ?
+              BM_elem_index_get((BMVert *)(v.i)) :
+              (v.i));
+}
+
+BLI_INLINE PBVHVertRef BKE_pbvh_index_to_vertex(PBVH *pbvh, int index)
+{
+  switch (BKE_pbvh_type(pbvh)) {
+    case PBVH_FACES:
+    case PBVH_GRIDS:
+      return BKE_pbvh_make_vref(index);
+    case PBVH_BMESH:
+      return BKE_pbvh_make_vref((intptr_t)BKE_pbvh_get_bmesh(pbvh)->vtable[index]);
+  }
+
+  return BKE_pbvh_make_vref(PBVH_REF_NONE);
+}
+
+BLI_INLINE int BKE_pbvh_edge_to_index(PBVH *pbvh, PBVHEdgeRef e)
+{
+  return (BKE_pbvh_type(pbvh) == PBVH_BMESH && e.i != PBVH_REF_NONE ?
+              BM_elem_index_get((BMEdge *)(e.i)) :
+              (e.i));
+}
+
+BLI_INLINE PBVHEdgeRef BKE_pbvh_index_to_edge(PBVH *pbvh, int index)
+{
+  switch (BKE_pbvh_type(pbvh)) {
+    case PBVH_FACES:
+    case PBVH_GRIDS:
+      return BKE_pbvh_make_eref(index);
+    case PBVH_BMESH:
+      return BKE_pbvh_make_eref((intptr_t)BKE_pbvh_get_bmesh(pbvh)->etable[index]);
+  }
+
+  return BKE_pbvh_make_eref(PBVH_REF_NONE);
+}
+
+BLI_INLINE int BKE_pbvh_face_to_index(PBVH *pbvh, PBVHFaceRef f)
+{
+  return (BKE_pbvh_type(pbvh) == PBVH_BMESH && f.i != PBVH_REF_NONE ?
+              BM_elem_index_get((BMFace *)(f.i)) :
+              (f.i));
+}
+
+BLI_INLINE PBVHFaceRef BKE_pbvh_index_to_face(PBVH *pbvh, int index)
+{
+  switch (BKE_pbvh_type(pbvh)) {
+    case PBVH_FACES:
+    case PBVH_GRIDS:
+      return BKE_pbvh_make_fref(index);
+    case PBVH_BMESH:
+      return BKE_pbvh_make_fref((intptr_t)BKE_pbvh_get_bmesh(pbvh)->ftable[index]);
+  }
+
+  return BKE_pbvh_make_fref(PBVH_REF_NONE);
+}
+
 /* Callbacks */
 
 /**
@@ -104,7 +230,7 @@ typedef void (*BKE_pbvh_SearchNearestCallback)(PBVHNode *node, void *data, float
 
 /* Building */
 
-PBVH *BKE_pbvh_new(void);
+PBVH *BKE_pbvh_new(PBVHType type);
 /**
  * Do a full rebuild with on Mesh data structure.
  *
@@ -142,6 +268,8 @@ void BKE_pbvh_build_bmesh(PBVH *pbvh,
                           int cd_vert_node_offset,
                           int cd_face_node_offset);
 
+void BKE_pbvh_update_bmesh_offsets(PBVH *pbvh, int cd_vert_node_offset, int cd_face_node_offset);
+
 void BKE_pbvh_build_pixels(PBVH *pbvh,
                            struct Mesh *mesh,
                            struct Image *image,
@@ -181,7 +309,7 @@ bool BKE_pbvh_node_raycast(PBVH *pbvh,
                            const float ray_normal[3],
                            struct IsectRayPrecalc *isect_precalc,
                            float *depth,
-                           int *active_vertex_index,
+                           PBVHVertRef *active_vertex,
                            int *active_face_grid_index,
                            float *face_normal);
 
@@ -224,19 +352,16 @@ void BKE_pbvh_draw_cb(PBVH *pbvh,
                       void *user_data,
                       bool full_render);
 
-void BKE_pbvh_draw_debug_cb(
-    PBVH *pbvh,
-    void (*draw_fn)(void *user_data, const float bmin[3], const float bmax[3], PBVHNodeFlags flag),
-    void *user_data);
+void BKE_pbvh_draw_debug_cb(PBVH *pbvh,
+                            void (*draw_fn)(PBVHNode *node,
+                                            void *user_data,
+                                            const float bmin[3],
+                                            const float bmax[3],
+                                            PBVHNodeFlags flag),
+                            void *user_data);
 
 /* PBVH Access */
-typedef enum {
-  PBVH_FACES,
-  PBVH_GRIDS,
-  PBVH_BMESH,
-} PBVHType;
 
-PBVHType BKE_pbvh_type(const PBVH *pbvh);
 bool BKE_pbvh_has_faces(const PBVH *pbvh);
 
 /**
@@ -257,8 +382,6 @@ int BKE_pbvh_count_grid_quads(BLI_bitmap **grid_hidden,
                               int totgrid,
                               int gridsize);
 
-void BKE_pbvh_sync_face_sets_to_grids(PBVH *pbvh);
-
 /**
  * Multi-res level, only valid for type == #PBVH_GRIDS.
  */
@@ -266,13 +389,12 @@ const struct CCGKey *BKE_pbvh_get_grid_key(const PBVH *pbvh);
 
 struct CCGElem **BKE_pbvh_get_grids(const PBVH *pbvh);
 BLI_bitmap **BKE_pbvh_get_grid_visibility(const PBVH *pbvh);
-int BKE_pbvh_get_grid_num_vertices(const PBVH *pbvh);
+int BKE_pbvh_get_grid_num_verts(const PBVH *pbvh);
 int BKE_pbvh_get_grid_num_faces(const PBVH *pbvh);
 
 /**
  * Only valid for type == #PBVH_BMESH.
  */
-struct BMesh *BKE_pbvh_get_bmesh(PBVH *pbvh);
 void BKE_pbvh_bmesh_detail_size_set(PBVH *pbvh, float detail_size);
 
 typedef enum {
@@ -308,7 +430,7 @@ void BKE_pbvh_node_fully_unmasked_set(PBVHNode *node, int fully_masked);
 bool BKE_pbvh_node_fully_unmasked_get(PBVHNode *node);
 
 void BKE_pbvh_mark_rebuild_pixels(PBVH *pbvh);
-void BKE_pbvh_vert_mark_update(PBVH *pbvh, int index);
+void BKE_pbvh_vert_tag_update_normal(PBVH *pbvh, PBVHVertRef vertex);
 
 void BKE_pbvh_node_get_grids(PBVH *pbvh,
                              PBVHNode *node,
@@ -369,6 +491,12 @@ void BKE_pbvh_grids_update(PBVH *pbvh,
 void BKE_pbvh_subdiv_cgg_set(PBVH *pbvh, struct SubdivCCG *subdiv_ccg);
 void BKE_pbvh_face_sets_set(PBVH *pbvh, int *face_sets);
 
+/**
+ * If an operation causes the hide status stored in the mesh to change, this must be called
+ * to update the references to those attributes, since they are only added when necessary.
+ */
+void BKE_pbvh_update_hide_attributes_from_mesh(PBVH *pbvh);
+
 void BKE_pbvh_face_sets_color_set(PBVH *pbvh, int seed, int color_default);
 
 void BKE_pbvh_respect_hide_set(PBVH *pbvh, bool respect_hide);
@@ -399,6 +527,7 @@ typedef struct PBVHVertexIter {
   int gy;
   int i;
   int index;
+  PBVHVertRef vertex;
   bool respect_hide;
 
   /* grid */
@@ -413,6 +542,7 @@ typedef struct PBVHVertexIter {
   /* mesh */
   struct MVert *mverts;
   float (*vert_normals)[3];
+  const bool *hide_vert;
   int totvert;
   const int *vert_indices;
   float *vmask;
@@ -443,7 +573,7 @@ void pbvh_vertex_iter_init(PBVH *pbvh, PBVHNode *node, PBVHVertexIter *vi, int m
     if (vi.grids) { \
       vi.width = vi.gridsize; \
       vi.height = vi.gridsize; \
-      vi.index = vi.grid_indices[vi.g] * vi.key.grid_area - 1; \
+      vi.index = vi.vertex.i = vi.grid_indices[vi.g] * vi.key.grid_area - 1; \
       vi.grid = vi.grids[vi.grid_indices[vi.g]]; \
       if (mode == PBVH_ITER_UNIQUE) { \
         vi.gh = vi.grid_hidden[vi.grid_indices[vi.g]]; \
@@ -462,6 +592,7 @@ void pbvh_vertex_iter_init(PBVH *pbvh, PBVHNode *node, PBVHVertexIter *vi, int m
           vi.mask = vi.key.has_mask ? CCG_elem_mask(&vi.key, vi.grid) : NULL; \
           vi.grid = CCG_elem_next(&vi.key, vi.grid); \
           vi.index++; \
+          vi.vertex.i++; \
           vi.visible = true; \
           if (vi.gh) { \
             if (BLI_BITMAP_TEST(vi.gh, vi.gy * vi.gridsize + vi.gx)) { \
@@ -472,7 +603,7 @@ void pbvh_vertex_iter_init(PBVH *pbvh, PBVHNode *node, PBVHVertexIter *vi, int m
         else if (vi.mverts) { \
           vi.mvert = &vi.mverts[vi.vert_indices[vi.gx]]; \
           if (vi.respect_hide) { \
-            vi.visible = !(vi.mvert->flag & ME_HIDE); \
+            vi.visible = !(vi.hide_vert && vi.hide_vert[vi.vert_indices[vi.gx]]); \
             if (mode == PBVH_ITER_UNIQUE && !vi.visible) { \
               continue; \
             } \
@@ -482,7 +613,7 @@ void pbvh_vertex_iter_init(PBVH *pbvh, PBVHNode *node, PBVHVertexIter *vi, int m
           } \
           vi.co = vi.mvert->co; \
           vi.no = vi.vert_normals[vi.vert_indices[vi.gx]]; \
-          vi.index = vi.vert_indices[vi.i]; \
+          vi.index = vi.vertex.i = vi.vert_indices[vi.i]; \
           if (vi.vmask) { \
             vi.mask = &vi.vmask[vi.index]; \
           } \
@@ -502,6 +633,7 @@ void pbvh_vertex_iter_init(PBVH *pbvh, PBVHNode *node, PBVHVertexIter *vi, int m
           } \
           vi.co = vi.bm_vert->co; \
           vi.fno = vi.bm_vert->no; \
+          vi.vertex = BKE_pbvh_make_vref((intptr_t)vi.bm_vert); \
           vi.index = BM_elem_index_get(vi.bm_vert); \
           vi.mask = (float *)BM_ELEM_CD_GET_VOID_P(vi.bm_vert, vi.cd_vert_mask_offset); \
         }
@@ -526,7 +658,7 @@ void BKE_pbvh_node_get_bm_orco_data(PBVHNode *node,
  * however this is important to avoid having to recalculate bound-box & sync the buffers to the
  * GPU (which is far more expensive!) See: T47232.
  */
-bool BKE_pbvh_node_vert_update_check_any(PBVH *pbvh, PBVHNode *node);
+bool BKE_pbvh_node_has_vert_with_normal_update_tag(PBVH *pbvh, PBVHNode *node);
 
 // void BKE_pbvh_node_BB_reset(PBVHNode *node);
 // void BKE_pbvh_node_BB_expand(PBVHNode *node, float co[3]);
@@ -545,6 +677,10 @@ void BKE_pbvh_parallel_range_settings(struct TaskParallelSettings *settings,
 
 struct MVert *BKE_pbvh_get_verts(const PBVH *pbvh);
 const float (*BKE_pbvh_get_vert_normals(const PBVH *pbvh))[3];
+const bool *BKE_pbvh_get_vert_hide(const PBVH *pbvh);
+bool *BKE_pbvh_get_vert_hide_for_write(PBVH *pbvh);
+
+const bool *BKE_pbvh_get_poly_hide(const PBVH *pbvh);
 
 PBVHColorBufferNode *BKE_pbvh_node_color_buffer_get(PBVHNode *node);
 void BKE_pbvh_node_color_buffer_free(PBVH *pbvh);
@@ -581,11 +717,12 @@ void BKE_pbvh_node_num_loops(PBVH *pbvh, PBVHNode *node, int *r_totloop);
 void BKE_pbvh_update_active_vcol(PBVH *pbvh, const struct Mesh *mesh);
 void BKE_pbvh_pmap_set(PBVH *pbvh, const struct MeshElemMap *pmap);
 
-void BKE_pbvh_vertex_color_set(PBVH *pbvh, int vertex, const float color[4]);
-void BKE_pbvh_vertex_color_get(const PBVH *pbvh, int vertex, float r_color[4]);
+void BKE_pbvh_vertex_color_set(PBVH *pbvh, PBVHVertRef vertex, const float color[4]);
+void BKE_pbvh_vertex_color_get(const PBVH *pbvh, PBVHVertRef vertex, float r_color[4]);
 
 void BKE_pbvh_ensure_node_loops(PBVH *pbvh);
 bool BKE_pbvh_draw_cache_invalid(const PBVH *pbvh);
+int BKE_pbvh_debug_draw_gen_get(PBVHNode *node);
 
 #ifdef __cplusplus
 }
diff --git a/source/blender/blenkernel/BKE_pbvh_pixels.hh b/source/blender/blenkernel/BKE_pbvh_pixels.hh
index e73950e6299..ad8eca2b36f 100644
--- a/source/blender/blenkernel/BKE_pbvh_pixels.hh
+++ b/source/blender/blenkernel/BKE_pbvh_pixels.hh
@@ -186,8 +186,14 @@ struct NodeData {
   {
     UDIMTilePixels *tile = find_tile_data(image_tile);
     if (tile && tile->flags.dirty) {
-      BKE_image_partial_update_mark_region(
-          &image, image_tile.image_tile, &image_buffer, &tile->dirty_region);
+      if (image_buffer.planes == 8) {
+        image_buffer.planes = 32;
+        BKE_image_partial_update_mark_full_update(&image);
+      }
+      else {
+        BKE_image_partial_update_mark_region(
+            &image, image_tile.image_tile, &image_buffer, &tile->dirty_region);
+      }
       tile->clear_dirty();
     }
   }
diff --git a/source/blender/blenkernel/BKE_pointcache.h b/source/blender/blenkernel/BKE_pointcache.h
index 48402123365..efb8c2a9bb1 100644
--- a/source/blender/blenkernel/BKE_pointcache.h
+++ b/source/blender/blenkernel/BKE_pointcache.h
@@ -285,7 +285,7 @@ void BKE_ptcache_ids_from_object(struct ListBase *lb,
                                  struct Scene *scene,
                                  int duplis);
 
-/****************** Query funcs ****************************/
+/****************** Query functions ****************************/
 
 /**
  * Check whether object has a point cache.
diff --git a/source/blender/blenkernel/BKE_pointcloud.h b/source/blender/blenkernel/BKE_pointcloud.h
index 6dbba11a56d..d6367ac5a61 100644
--- a/source/blender/blenkernel/BKE_pointcloud.h
+++ b/source/blender/blenkernel/BKE_pointcloud.h
@@ -25,17 +25,17 @@ extern const char *POINTCLOUD_ATTR_RADIUS;
 void *BKE_pointcloud_add(struct Main *bmain, const char *name);
 void *BKE_pointcloud_add_default(struct Main *bmain, const char *name);
 struct PointCloud *BKE_pointcloud_new_nomain(int totpoint);
+void BKE_pointcloud_nomain_to_pointcloud(struct PointCloud *pointcloud_src,
+                                         struct PointCloud *pointcloud_dst,
+                                         bool take_ownership);
 
 struct BoundBox *BKE_pointcloud_boundbox_get(struct Object *ob);
 bool BKE_pointcloud_minmax(const struct PointCloud *pointcloud, float r_min[3], float r_max[3]);
 
-void BKE_pointcloud_update_customdata_pointers(struct PointCloud *pointcloud);
-bool BKE_pointcloud_customdata_required(const struct PointCloud *pointcloud, const char *name);
+bool BKE_pointcloud_attribute_required(const struct PointCloud *pointcloud, const char *name);
 
 /* Dependency Graph */
 
-struct PointCloud *BKE_pointcloud_new_for_eval(const struct PointCloud *pointcloud_src,
-                                               int totpoint);
 struct PointCloud *BKE_pointcloud_copy_for_eval(struct PointCloud *pointcloud_src, bool reference);
 
 void BKE_pointcloud_data_update(struct Depsgraph *depsgraph,
diff --git a/source/blender/blenkernel/BKE_scene.h b/source/blender/blenkernel/BKE_scene.h
index a6402a1e8a1..c6ccd4493fe 100644
--- a/source/blender/blenkernel/BKE_scene.h
+++ b/source/blender/blenkernel/BKE_scene.h
@@ -97,7 +97,7 @@ int BKE_scene_base_iter_next(struct Depsgraph *depsgraph,
                              struct Base **base,
                              struct Object **ob);
 
-void BKE_scene_base_flag_to_objects(struct ViewLayer *view_layer);
+void BKE_scene_base_flag_to_objects(const struct Scene *scene, struct ViewLayer *view_layer);
 /**
  * Synchronize object base flags
  *
@@ -251,6 +251,10 @@ bool BKE_scene_check_rigidbody_active(const struct Scene *scene);
 int BKE_scene_num_threads(const struct Scene *scene);
 int BKE_render_num_threads(const struct RenderData *r);
 
+void BKE_render_resolution(const struct RenderData *r,
+                           const bool use_crop,
+                           int *r_width,
+                           int *r_height);
 int BKE_render_preview_pixel_size(const struct RenderData *r);
 
 /**********************************/
diff --git a/source/blender/blenkernel/BKE_screen.h b/source/blender/blenkernel/BKE_screen.h
index 3922bfb6c0d..62b04785983 100644
--- a/source/blender/blenkernel/BKE_screen.h
+++ b/source/blender/blenkernel/BKE_screen.h
@@ -55,7 +55,7 @@ struct wmWindowManager;
 typedef struct wmSpaceTypeListenerParams {
   struct wmWindow *window;
   struct ScrArea *area;
-  struct wmNotifier *notifier;
+  const struct wmNotifier *notifier;
   const struct Scene *scene;
 } wmSpaceTypeListenerParams;
 
@@ -113,7 +113,7 @@ typedef struct SpaceType {
 
   /* read and write... */
 
-  /* default keymaps to add */
+  /** Default key-maps to add. */
   int keymapflag;
 
 } SpaceType;
@@ -124,7 +124,7 @@ typedef struct wmRegionListenerParams {
   struct wmWindow *window;
   struct ScrArea *area; /* Can be NULL when the region is not part of an area. */
   struct ARegion *region;
-  struct wmNotifier *notifier;
+  const struct wmNotifier *notifier;
   const struct Scene *scene;
 } wmRegionListenerParams;
 
@@ -291,7 +291,7 @@ enum {
 
 /* Draw an item in the uiList */
 typedef void (*uiListDrawItemFunc)(struct uiList *ui_list,
-                                   struct bContext *C,
+                                   const struct bContext *C,
                                    struct uiLayout *layout,
                                    struct PointerRNA *dataptr,
                                    struct PointerRNA *itemptr,
@@ -303,12 +303,12 @@ typedef void (*uiListDrawItemFunc)(struct uiList *ui_list,
 
 /* Draw the filtering part of an uiList */
 typedef void (*uiListDrawFilterFunc)(struct uiList *ui_list,
-                                     struct bContext *C,
+                                     const struct bContext *C,
                                      struct uiLayout *layout);
 
 /* Filter items of an uiList */
 typedef void (*uiListFilterItemsFunc)(struct uiList *ui_list,
-                                      struct bContext *C,
+                                      const struct bContext *C,
                                       struct PointerRNA *,
                                       const char *propname);
 
diff --git a/source/blender/blenkernel/BKE_shrinkwrap.h b/source/blender/blenkernel/BKE_shrinkwrap.h
index 3e06bd84805..b4f87e6fc73 100644
--- a/source/blender/blenkernel/BKE_shrinkwrap.h
+++ b/source/blender/blenkernel/BKE_shrinkwrap.h
@@ -30,6 +30,7 @@ struct BVHTree;
 struct MDeformVert;
 struct Mesh;
 struct ModifierEvalContext;
+struct MPoly;
 struct Object;
 struct ShrinkwrapGpencilModifierData;
 struct ShrinkwrapModifierData;
@@ -72,6 +73,7 @@ typedef struct ShrinkwrapTreeData {
   BVHTree *bvh;
   BVHTreeFromMesh treeData;
 
+  const struct MPoly *polys;
   const float (*pnors)[3];
   const float (*clnors)[3];
   ShrinkwrapBoundaryData *boundary;
@@ -104,7 +106,7 @@ void shrinkwrapModifier_deform(struct ShrinkwrapModifierData *smd,
                                struct Scene *scene,
                                struct Object *ob,
                                struct Mesh *mesh,
-                               struct MDeformVert *dvert,
+                               const struct MDeformVert *dvert,
                                int defgrp_index,
                                float (*vertexCos)[3],
                                int numVerts);
diff --git a/source/blender/blenkernel/BKE_sound.h b/source/blender/blenkernel/BKE_sound.h
index 9965b6f1351..11c37a74a54 100644
--- a/source/blender/blenkernel/BKE_sound.h
+++ b/source/blender/blenkernel/BKE_sound.h
@@ -134,7 +134,7 @@ void *BKE_sound_add_scene_sound_defaults(struct Scene *scene, struct Sequence *s
 
 void BKE_sound_remove_scene_sound(struct Scene *scene, void *handle);
 
-void BKE_sound_mute_scene_sound(void *handle, char mute);
+void BKE_sound_mute_scene_sound(void *handle, bool mute);
 
 void BKE_sound_move_scene_sound(const struct Scene *scene,
                                 void *handle,
diff --git a/source/blender/blenkernel/BKE_spline.hh b/source/blender/blenkernel/BKE_spline.hh
deleted file mode 100644
index 767018ae0bb..00000000000
--- a/source/blender/blenkernel/BKE_spline.hh
+++ /dev/null
@@ -1,688 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-
-#pragma once
-
-/** \file
- * \ingroup bke
- */
-
-#include 
-
-#include "DNA_curves_types.h"
-
-#include "BLI_float4x4.hh"
-#include "BLI_generic_virtual_array.hh"
-#include "BLI_math_vec_types.hh"
-#include "BLI_vector.hh"
-
-#include "BKE_attribute.hh"
-#include "BKE_attribute_math.hh"
-
-struct Curve;
-struct Curves;
-struct ListBase;
-
-class Spline;
-using SplinePtr = std::unique_ptr;
-
-/**
- * A spline is an abstraction of a single branch-less curve section, its evaluation methods,
- * and data. The spline data itself is just control points and a set of attributes by the set
- * of "evaluated" data is often used instead. Conceptually, the derived vs. original data is
- * an essential distinction. Derived data is usually calculated lazily and cached on the spline.
- *
- * Any derived class of Spline has to manage two things:
- *  1. Interpolating arbitrary attribute data from the control points to evaluated points.
- *  2. Evaluating the positions based on the stored control point data.
- *
- * Beyond that, everything is the base class's responsibility, with minor exceptions. Further
- * evaluation happens in a layer on top of the evaluated points generated by the derived types.
- *
- * There are a few methods to evaluate a spline:
- *  1. #evaluated_positions and #interpolate_to_evaluated give data for the initial
- *     evaluated points, depending on the resolution.
- *  2. #lookup_evaluated_factor and #lookup_evaluated_factor are meant for one-off lookups
- *     along the length of a curve.
- *  3. #sample_uniform_index_factors returns an array that stores uniform-length samples
- *     along the spline which can be used to interpolate data from method 1.
- *
- * Commonly used evaluated data is stored in caches on the spline itself so that operations on
- * splines don't need to worry about taking ownership of evaluated data when they don't need to.
- */
-class Spline {
- public:
-  NormalMode normal_mode = NORMAL_MODE_MINIMUM_TWIST;
-
-  blender::bke::CustomDataAttributes attributes;
-
- protected:
-  CurveType type_;
-  bool is_cyclic_ = false;
-
-  /** Direction of the spline at each evaluated point. */
-  mutable blender::Vector evaluated_tangents_cache_;
-  mutable std::mutex tangent_cache_mutex_;
-  mutable bool tangent_cache_dirty_ = true;
-
-  /** Normal direction vectors for each evaluated point. */
-  mutable blender::Vector evaluated_normals_cache_;
-  mutable std::mutex normal_cache_mutex_;
-  mutable bool normal_cache_dirty_ = true;
-
-  /** Accumulated lengths along the evaluated points. */
-  mutable blender::Vector evaluated_lengths_cache_;
-  mutable std::mutex length_cache_mutex_;
-  mutable bool length_cache_dirty_ = true;
-
- public:
-  virtual ~Spline() = default;
-  Spline(const CurveType type) : type_(type)
-  {
-  }
-  Spline(Spline &other) : attributes(other.attributes), type_(other.type_)
-  {
-    copy_base_settings(other, *this);
-  }
-
-  /**
-   * Return a new spline with the same data, settings, and attributes.
-   */
-  SplinePtr copy() const;
-  /**
-   * Return a new spline with the same type and settings like "cyclic", but without any data.
-   */
-  SplinePtr copy_only_settings() const;
-  /**
-   * The same as #copy, but skips copying dynamic attributes to the new spline.
-   */
-  SplinePtr copy_without_attributes() const;
-  static void copy_base_settings(const Spline &src, Spline &dst);
-
-  CurveType type() const;
-
-  /** Return the number of control points. */
-  virtual int size() const = 0;
-  int segments_num() const;
-  bool is_cyclic() const;
-  void set_cyclic(bool value);
-
-  virtual void resize(int size) = 0;
-  virtual blender::MutableSpan positions() = 0;
-  virtual blender::Span positions() const = 0;
-  virtual blender::MutableSpan radii() = 0;
-  virtual blender::Span radii() const = 0;
-  virtual blender::MutableSpan tilts() = 0;
-  virtual blender::Span tilts() const = 0;
-
-  virtual void translate(const blender::float3 &translation);
-  virtual void transform(const blender::float4x4 &matrix);
-
-  /**
-   * Change the direction of the spline (switch the start and end) without changing its shape.
-   */
-  void reverse();
-
-  /**
-   * Mark all caches for re-computation. This must be called after any operation that would
-   * change the generated positions, tangents, normals, mapping, etc. of the evaluated points.
-   */
-  virtual void mark_cache_invalid() = 0;
-  virtual int evaluated_points_num() const = 0;
-  int evaluated_edges_num() const;
-
-  float length() const;
-
-  virtual blender::Span evaluated_positions() const = 0;
-
-  /**
-   * Return non-owning access to the cache of accumulated lengths along the spline. Each item is
-   * the length of the subsequent segment, i.e. the first value is the length of the first segment
-   * rather than 0. This calculation is rather trivial, and only depends on the evaluated
-   * positions. However, the results are used often, and it is necessarily single threaded, so it
-   * is cached.
-   */
-  blender::Span evaluated_lengths() const;
-  /**
-   * Return non-owning access to the direction of the curve at each evaluated point.
-   */
-  blender::Span evaluated_tangents() const;
-  /**
-   * Return non-owning access to the direction vectors perpendicular to the tangents at every
-   * evaluated point. The method used to generate the normal vectors depends on Spline.normal_mode.
-   */
-  blender::Span evaluated_normals() const;
-
-  void bounds_min_max(blender::float3 &min, blender::float3 &max, bool use_evaluated) const;
-
-  struct LookupResult {
-    /**
-     * The index of the evaluated point before the result location. In other words, the index of
-     * the edge that the result lies on. If the sampled factor/length is the very end of the
-     * spline, this will be the second to last index, if it's the very beginning, this will be 0.
-     */
-    int evaluated_index;
-    /**
-     * The index of the evaluated point after the result location, accounting for wrapping when
-     * the spline is cyclic. If the sampled factor/length is the very end of the spline, this will
-     * be the last index (#evaluated_points_num - 1).
-     */
-    int next_evaluated_index;
-    /**
-     * The portion of the way from the evaluated point at #evaluated_index to the next point.
-     * If the sampled factor/length is the very end of the spline, this will be the 1.0f
-     */
-    float factor;
-  };
-  /**
-   * Find the position on the evaluated spline at the given portion of the total length.
-   * The return value is the indices of the two neighboring points at that location and the
-   * factor between them, which can be used to look up any attribute on the evaluated points.
-   * \note This does not support extrapolation.
-   */
-  LookupResult lookup_evaluated_factor(float factor) const;
-  /**
-   * The same as #lookup_evaluated_factor, but looks up a length directly instead of
-   * a portion of the total.
-   */
-  LookupResult lookup_evaluated_length(float length) const;
-
-  /**
-   * Return an array of evenly spaced samples along the length of the spline. The samples are
-   * indices and factors to the next index encoded in floats. The logic for converting from the
-   * float values to interpolation data is in #lookup_data_from_index_factor.
-   */
-  blender::Array sample_uniform_index_factors(int samples_num) const;
-  LookupResult lookup_data_from_index_factor(float index_factor) const;
-
-  /**
-   * Sample any input data with a value for each evaluated point (already interpolated to evaluated
-   * points) to arbitrary parameters in between the evaluated points. The interpolation is quite
-   * simple, but this handles the cyclic and end point special cases.
-   */
-  void sample_with_index_factors(const blender::GVArray &src,
-                                 blender::Span index_factors,
-                                 blender::GMutableSpan dst) const;
-  template
-  void sample_with_index_factors(const blender::VArray &src,
-                                 blender::Span index_factors,
-                                 blender::MutableSpan dst) const
-  {
-    this->sample_with_index_factors(
-        blender::GVArray(src), index_factors, blender::GMutableSpan(dst));
-  }
-  template
-  void sample_with_index_factors(blender::Span src,
-                                 blender::Span index_factors,
-                                 blender::MutableSpan dst) const
-  {
-    this->sample_with_index_factors(blender::VArray::ForSpan(src), index_factors, dst);
-  }
-
-  /**
-   * Interpolate a virtual array of data with the size of the number of control points to the
-   * evaluated points. For poly splines, the lifetime of the returned virtual array must not
-   * exceed the lifetime of the input data.
-   */
-  virtual blender::GVArray interpolate_to_evaluated(const blender::GVArray &src) const = 0;
-  blender::GVArray interpolate_to_evaluated(blender::GSpan data) const;
-  template blender::VArray interpolate_to_evaluated(blender::Span data) const
-  {
-    return this->interpolate_to_evaluated(blender::GSpan(data)).typed();
-  }
-
- protected:
-  virtual void correct_end_tangents() const = 0;
-  virtual void copy_settings(Spline &dst) const = 0;
-  virtual void copy_data(Spline &dst) const = 0;
-  virtual void reverse_impl() = 0;
-};
-
-/**
- * A Bezier spline is made up of a many curve segments, possibly achieving continuity of curvature
- * by constraining the alignment of curve handles. Evaluation stores the positions and a map of
- * factors and indices in a list of floats, which is then used to interpolate any other data.
- */
-class BezierSpline final : public Spline {
-  blender::Vector positions_;
-  blender::Vector radii_;
-  blender::Vector tilts_;
-  int resolution_;
-
-  blender::Vector handle_types_left_;
-  blender::Vector handle_types_right_;
-
-  /* These are mutable to allow lazy recalculation of #Auto and #Vector handle positions. */
-  mutable blender::Vector handle_positions_left_;
-  mutable blender::Vector handle_positions_right_;
-
-  mutable std::mutex auto_handle_mutex_;
-  mutable bool auto_handles_dirty_ = true;
-
-  /** Start index in evaluated points array for every control point. */
-  mutable blender::Vector offset_cache_;
-  mutable std::mutex offset_cache_mutex_;
-  mutable bool offset_cache_dirty_ = true;
-
-  /** Cache of evaluated positions. */
-  mutable blender::Vector evaluated_position_cache_;
-  mutable std::mutex position_cache_mutex_;
-  mutable bool position_cache_dirty_ = true;
-
-  /** Cache of "index factors" based calculated from the evaluated positions. */
-  mutable blender::Vector evaluated_mapping_cache_;
-  mutable std::mutex mapping_cache_mutex_;
-  mutable bool mapping_cache_dirty_ = true;
-
- public:
-  BezierSpline() : Spline(CURVE_TYPE_BEZIER)
-  {
-  }
-  BezierSpline(const BezierSpline &other)
-      : Spline((Spline &)other),
-        positions_(other.positions_),
-        radii_(other.radii_),
-        tilts_(other.tilts_),
-        resolution_(other.resolution_),
-        handle_types_left_(other.handle_types_left_),
-        handle_types_right_(other.handle_types_right_),
-        handle_positions_left_(other.handle_positions_left_),
-        handle_positions_right_(other.handle_positions_right_)
-  {
-  }
-
-  int size() const final;
-  int resolution() const;
-  void set_resolution(int value);
-
-  void resize(int size) final;
-  blender::MutableSpan positions() final;
-  blender::Span positions() const final;
-  blender::MutableSpan radii() final;
-  blender::Span radii() const final;
-  blender::MutableSpan tilts() final;
-  blender::Span tilts() const final;
-  blender::Span handle_types_left() const;
-  blender::MutableSpan handle_types_left();
-  blender::Span handle_positions_left() const;
-  /**
-   * Get writable access to the handle position.
-   *
-   * \param write_only: pass true for an uninitialized spline, this prevents accessing
-   * uninitialized memory while auto-generating handles.
-   */
-  blender::MutableSpan handle_positions_left(bool write_only = false);
-  blender::Span handle_types_right() const;
-  blender::MutableSpan handle_types_right();
-  blender::Span handle_positions_right() const;
-  /**
-   * Get writable access to the handle position.
-   *
-   * \param write_only: pass true for an uninitialized spline, this prevents accessing
-   * uninitialized memory while auto-generating handles.
-   */
-  blender::MutableSpan handle_positions_right(bool write_only = false);
-  /**
-   * Recalculate all #Auto and #Vector handles with positions automatically
-   * derived from the neighboring control points.
-   */
-  void ensure_auto_handles() const;
-
-  void translate(const blender::float3 &translation) override;
-  void transform(const blender::float4x4 &matrix) override;
-
-  /**
-   * Set positions for the right handle of the control point, ensuring that
-   * aligned handles stay aligned. Has no effect for auto and vector type handles.
-   */
-  void set_handle_position_right(int index, const blender::float3 &value);
-  /**
-   * Set positions for the left handle of the control point, ensuring that
-   * aligned handles stay aligned. Has no effect for auto and vector type handles.
-   */
-  void set_handle_position_left(int index, const blender::float3 &value);
-
-  bool point_is_sharp(int index) const;
-
-  void mark_cache_invalid() final;
-  int evaluated_points_num() const final;
-
-  /**
-   * Returns access to a cache of offsets into the evaluated point array for each control point.
-   * While most control point edges generate the number of edges specified by the resolution,
-   * vector segments only generate one edge.
-   *
-   * \note The length of the result is one greater than the number of points, so that the last item
-   * is the total number of evaluated points. This is useful to avoid recalculating the size of the
-   * last segment everywhere.
-   */
-  blender::Span control_point_offsets() const;
-  /**
-   * Returns non-owning access to an array of values containing the information necessary to
-   * interpolate values from the original control points to evaluated points. The control point
-   * index is the integer part of each value, and the factor used for interpolating to the next
-   * control point is the remaining factional part.
-   */
-  blender::Span evaluated_mappings() const;
-  blender::Span evaluated_positions() const final;
-  struct InterpolationData {
-    int control_point_index;
-    int next_control_point_index;
-    /**
-     * Linear interpolation weight between the two indices, from 0 to 1.
-     * Higher means closer to next control point.
-     */
-    float factor;
-  };
-  /**
-   * Convert the data encoded in #evaulated_mappings into its parts-- the information necessary
-   * to interpolate data from control points to evaluated points between them. The next control
-   * point index result will not overflow the size of the control point vectors.
-   */
-  InterpolationData interpolation_data_from_index_factor(float index_factor) const;
-
-  virtual blender::GVArray interpolate_to_evaluated(const blender::GVArray &src) const override;
-
-  void evaluate_segment(int index,
-                        int next_index,
-                        blender::MutableSpan positions) const;
-  /**
-   * \warning This functional assumes that the spline has more than one point.
-   */
-  bool segment_is_vector(int start_index) const;
-
-  /** See comment and diagram for #calculate_segment_insertion. */
-  struct InsertResult {
-    blender::float3 handle_prev;
-    blender::float3 left_handle;
-    blender::float3 position;
-    blender::float3 right_handle;
-    blender::float3 handle_next;
-  };
-  /**
-   * De Casteljau Bezier subdivision.
-   * \param index: The index of the segment's start control point.
-   * \param next_index: The index of the control point at the end of the segment. Could be 0,
-   * if the spline is cyclic.
-   * \param parameter: The factor along the segment, between 0 and 1. Note that this is used
-   * directly by the calculation, it doesn't correspond to a portion of the evaluated length.
-   *
-   * 
-   *           handle_prev         handle_next
-   *                x----------------x
-   *               /                  \
-   *              /      x---O---x     \
-   *             /        result        \
-   *            /                        \
-   *           O                          O
-   *       point_prev                  point_next
-   * 

-   */
-  InsertResult calculate_segment_insertion(int index, int next_index, float parameter);
-
- private:
-  /**
-   * If the spline is not cyclic, the direction for the first and last points is just the
-   * direction formed by the corresponding handles and control points. In the unlikely situation
-   * that the handles define a zero direction, fallback to using the direction defined by the
-   * first and last evaluated segments already calculated in #Spline::evaluated_tangents().
-   */
-  void correct_end_tangents() const final;
-  void copy_settings(Spline &dst) const final;
-  void copy_data(Spline &dst) const final;
-
- protected:
-  void reverse_impl() override;
-};
-
-/**
- * Data for Non-Uniform Rational B-Splines. The mapping from control points to evaluated points is
- * influenced by a vector of knots, weights for each point, and the order of the spline. Every
- * mapping of data to evaluated points is handled the same way, but the positions are cached in
- * the spline.
- */
-class NURBSpline final : public Spline {
- public:
-  /** Method used to recalculate the knots vector when points are added or removed. */
-  KnotsMode knots_mode;
-
-  struct BasisCache {
-    /**
-     * For each evaluated point, the weight for all control points that influences it.
-     * The vector's size is the evaluated point count multiplied by the spline's order.
-     */
-    blender::Vector weights;
-    /**
-     * An offset for the start of #weights: the first control point index with a non-zero weight.
-     */
-    blender::Vector start_indices;
-  };
-
- private:
-  blender::Vector positions_;
-  blender::Vector radii_;
-  blender::Vector tilts_;
-  blender::Vector weights_;
-  int resolution_;
-  /**
-   * Defines the number of nearby control points that influence a given evaluated point. Higher
-   * orders give smoother results. The number of control points must be greater than or equal to
-   * this value.
-   */
-  uint8_t order_;
-
-  /**
-   * Determines where and how the control points affect the evaluated points. The length should
-   * always be the value returned by #knots_num(), and each value should be greater than or equal
-   * to the previous. Only invalidated when a point is added or removed.
-   */
-  mutable blender::Vector knots_;
-  mutable std::mutex knots_mutex_;
-  mutable bool knots_dirty_ = true;
-
-  /** Cache of control point influences on each evaluated point. */
-  mutable BasisCache basis_cache_;
-  mutable std::mutex basis_cache_mutex_;
-  mutable bool basis_cache_dirty_ = true;
-
-  /**
-   * Cache of position data calculated from the basis cache. Though it is interpolated
-   * in the same way as any other attribute, it is stored to save unnecessary recalculation.
-   */
-  mutable blender::Vector evaluated_position_cache_;
-  mutable std::mutex position_cache_mutex_;
-  mutable bool position_cache_dirty_ = true;
-
- public:
-  NURBSpline() : Spline(CURVE_TYPE_NURBS)
-  {
-  }
-  NURBSpline(const NURBSpline &other)
-      : Spline((Spline &)other),
-        knots_mode(other.knots_mode),
-        positions_(other.positions_),
-        radii_(other.radii_),
-        tilts_(other.tilts_),
-        weights_(other.weights_),
-        resolution_(other.resolution_),
-        order_(other.order_)
-  {
-  }
-
-  int size() const final;
-  int resolution() const;
-  void set_resolution(int value);
-  uint8_t order() const;
-  void set_order(uint8_t value);
-
-  bool check_valid_num_and_order() const;
-  int knots_num() const;
-
-  void resize(int size) final;
-  blender::MutableSpan positions() final;
-  blender::Span positions() const final;
-  blender::MutableSpan radii() final;
-  blender::Span radii() const final;
-  blender::MutableSpan tilts() final;
-  blender::Span tilts() const final;
-  blender::Span knots() const;
-
-  blender::MutableSpan weights();
-  blender::Span weights() const;
-
-  void mark_cache_invalid() final;
-  int evaluated_points_num() const final;
-
-  blender::Span evaluated_positions() const final;
-
-  blender::GVArray interpolate_to_evaluated(const blender::GVArray &src) const final;
-
- protected:
-  void correct_end_tangents() const final;
-  void copy_settings(Spline &dst) const final;
-  void copy_data(Spline &dst) const final;
-  void reverse_impl() override;
-
-  void calculate_knots() const;
-  const BasisCache &calculate_basis_cache() const;
-};
-
-/**
- * A Poly spline is like a Bezier spline with a resolution of one. The main reason to distinguish
- * the two is for reduced complexity and increased performance, since interpolating data to control
- * points does not change it.
- *
- * Poly spline code is very simple, since it doesn't do anything that the base #Spline doesn't
- * handle. Mostly it just worries about storing the data used by the base class.
- */
-class PolySpline final : public Spline {
-  blender::Vector positions_;
-  blender::Vector radii_;
-  blender::Vector tilts_;
-
- public:
-  PolySpline() : Spline(CURVE_TYPE_POLY)
-  {
-  }
-  PolySpline(const PolySpline &other)
-      : Spline((Spline &)other),
-        positions_(other.positions_),
-        radii_(other.radii_),
-        tilts_(other.tilts_)
-  {
-  }
-
-  int size() const final;
-
-  void resize(int size) final;
-  blender::MutableSpan positions() final;
-  blender::Span positions() const final;
-  blender::MutableSpan radii() final;
-  blender::Span radii() const final;
-  blender::MutableSpan tilts() final;
-  blender::Span tilts() const final;
-
-  void mark_cache_invalid() final;
-  int evaluated_points_num() const final;
-
-  blender::Span evaluated_positions() const final;
-
-  /**
-   * Poly spline interpolation from control points to evaluated points is a special case, since
-   * the result data is the same as the input data. This function returns a #GVArray that points to
-   * the original data. Therefore the lifetime of the returned virtual array must not be longer
-   * than the source data.
-   */
-  blender::GVArray interpolate_to_evaluated(const blender::GVArray &src) const final;
-
- protected:
-  void correct_end_tangents() const final;
-  void copy_settings(Spline &dst) const final;
-  void copy_data(Spline &dst) const final;
-  void reverse_impl() override;
-};
-
-/**
- * A collection of #Spline objects with the same attribute types and names. Most data and
- * functionality is in splines, but this contains some helpers for working with them as a group.
- *
- * \note A #CurveEval corresponds to the #Curve object data. The name is different for clarity,
- * since more of the data is stored in the splines, but also just to be different than the name in
- * DNA.
- */
-struct CurveEval {
- private:
-  blender::Vector splines_;
-
- public:
-  blender::bke::CustomDataAttributes attributes;
-
-  CurveEval() = default;
-  CurveEval(const CurveEval &other) : attributes(other.attributes)
-  {
-    for (const SplinePtr &spline : other.splines()) {
-      this->add_spline(spline->copy());
-    }
-  }
-
-  blender::Span splines() const;
-  blender::MutableSpan splines();
-  /**
-   * \return True if the curve contains a spline with the given type.
-   *
-   * \note If you are looping over all of the splines in the same scope anyway,
-   * it's better to avoid calling this function, in case there are many splines.
-   */
-  bool has_spline_with_type(const CurveType type) const;
-
-  void resize(int size);
-  /**
-   * \warning Call #reallocate on the spline's attributes after adding all splines.
-   */
-  void add_spline(SplinePtr spline);
-  void add_splines(blender::MutableSpan splines);
-  void remove_splines(blender::IndexMask mask);
-
-  void translate(const blender::float3 &translation);
-  void transform(const blender::float4x4 &matrix);
-  bool bounds_min_max(blender::float3 &min, blender::float3 &max, bool use_evaluated) const;
-
-  blender::bke::MutableAttributeAccessor attributes_for_write();
-
-  /**
-   * Return the start indices for each of the curve spline's control points, if they were part
-   * of a flattened array. This can be used to facilitate parallelism by avoiding the need to
-   * accumulate an offset while doing more complex calculations.
-   *
-   * \note The result is one longer than the spline count; the last element is the total size.
-   */
-  blender::Array control_point_offsets() const;
-  /**
-   * Exactly like #control_point_offsets, but uses the number of evaluated points instead.
-   */
-  blender::Array evaluated_point_offsets() const;
-  /**
-   * Return the accumulated length at the start of every spline in the curve.
-   * \note The result is one longer than the spline count; the last element is the total length.
-   */
-  blender::Array accumulated_spline_lengths() const;
-
-  float total_length() const;
-  int total_control_point_num() const;
-
-  void mark_cache_invalid();
-
-  /**
-   * Check the invariants that curve control point attributes should always uphold, necessary
-   * because attributes are stored on splines rather than in a flat array on the curve:
-   *  - The same set of attributes exists on every spline.
-   *  - Attributes with the same name have the same type on every spline.
-   *  - Attributes are in the same order on every spline.
-   */
-  void assert_valid_point_attributes() const;
-};
-
-std::unique_ptr curve_eval_from_dna_curve(const Curve &curve,
-                                                     const ListBase &nurbs_list);
-std::unique_ptr curve_eval_from_dna_curve(const Curve &dna_curve);
-std::unique_ptr curves_to_curve_eval(const Curves &curves);
-Curves *curve_eval_to_curves(const CurveEval &curve_eval);
diff --git a/source/blender/blenkernel/BKE_subdiv_ccg.h b/source/blender/blenkernel/BKE_subdiv_ccg.h
index b30b707759c..ced7ff2aa71 100644
--- a/source/blender/blenkernel/BKE_subdiv_ccg.h
+++ b/source/blender/blenkernel/BKE_subdiv_ccg.h
@@ -325,6 +325,7 @@ const int *BKE_subdiv_ccg_start_face_grid_index_ensure(SubdivCCG *subdiv_ccg);
 const int *BKE_subdiv_ccg_start_face_grid_index_get(const SubdivCCG *subdiv_ccg);
 
 void BKE_subdiv_ccg_grid_hidden_ensure(SubdivCCG *subdiv_ccg, int grid_index);
+void BKE_subdiv_ccg_grid_hidden_free(SubdivCCG *subdiv_ccg, int grid_index);
 
 #ifdef __cplusplus
 }
diff --git a/source/blender/blenkernel/BKE_subdiv_eval.h b/source/blender/blenkernel/BKE_subdiv_eval.h
index cb0f2ac7e32..e4a7f813a8b 100644
--- a/source/blender/blenkernel/BKE_subdiv_eval.h
+++ b/source/blender/blenkernel/BKE_subdiv_eval.h
@@ -20,7 +20,7 @@ struct Subdiv;
 
 typedef enum eSubdivEvaluatorType {
   SUBDIV_EVALUATOR_TYPE_CPU,
-  SUBDIV_EVALUATOR_TYPE_GLSL_COMPUTE,
+  SUBDIV_EVALUATOR_TYPE_GPU,
 } eSubdivEvaluatorType;
 
 /* Returns true if evaluator is ready for use. */
diff --git a/source/blender/blenkernel/BKE_subdiv_mesh.h b/source/blender/blenkernel/BKE_subdiv_mesh.h
index b24db517143..49c45efafe0 100644
--- a/source/blender/blenkernel/BKE_subdiv_mesh.h
+++ b/source/blender/blenkernel/BKE_subdiv_mesh.h
@@ -14,7 +14,9 @@ extern "C" {
 #endif
 
 struct Mesh;
+struct MeshElemMap;
 struct MEdge;
+struct MVert;
 struct Subdiv;
 
 typedef struct SubdivToMeshSettings {
@@ -37,8 +39,10 @@ struct Mesh *BKE_subdiv_to_mesh(struct Subdiv *subdiv,
 /* Interpolate a position along the `coarse_edge` at the relative `u` coordinate. If `is_simple` is
  * false, this will perform a B-Spline interpolation using the edge neighbors, otherwise a linear
  * interpolation will be done base on the edge vertices. */
-void BKE_subdiv_mesh_interpolate_position_on_edge(const struct Mesh *coarse_mesh,
-                                                  const struct MEdge *coarse_edge,
+void BKE_subdiv_mesh_interpolate_position_on_edge(const struct MVert *coarse_verts,
+                                                  const struct MEdge *coarse_edges,
+                                                  const struct MeshElemMap *vert_to_edge_map,
+                                                  int coarse_edge_index,
                                                   bool is_simple,
                                                   float u,
                                                   float pos_r[3]);
diff --git a/source/blender/blenkernel/BKE_volume.h b/source/blender/blenkernel/BKE_volume.h
index bc578ef8b28..8549cd14b3c 100644
--- a/source/blender/blenkernel/BKE_volume.h
+++ b/source/blender/blenkernel/BKE_volume.h
@@ -114,6 +114,7 @@ int BKE_volume_grid_channels(const struct VolumeGrid *grid);
  * Transformation from index space to object space.
  */
 void BKE_volume_grid_transform_matrix(const struct VolumeGrid *grid, float mat[4][4]);
+void BKE_volume_grid_transform_matrix_set(struct VolumeGrid *volume_grid, const float mat[4][4]);
 
 /* Volume Editing
  *
@@ -133,6 +134,11 @@ struct VolumeGrid *BKE_volume_grid_add(struct Volume *volume,
                                        VolumeGridType type);
 void BKE_volume_grid_remove(struct Volume *volume, struct VolumeGrid *grid);
 
+/**
+ * OpenVDB crashes when the determinant of the transform matrix becomes too small.
+ */
+bool BKE_volume_grid_determinant_valid(double determinant);
+
 /* Simplify */
 int BKE_volume_simplify_level(const struct Depsgraph *depsgraph);
 float BKE_volume_simplify_factor(const struct Depsgraph *depsgraph);
@@ -186,6 +192,9 @@ openvdb::GridBase::Ptr BKE_volume_grid_openvdb_for_write(const struct Volume *vo
                                                          struct VolumeGrid *grid,
                                                          bool clear);
 
+void BKE_volume_grid_clear_tree(Volume &volume, VolumeGrid &volume_grid);
+void BKE_volume_grid_clear_tree(openvdb::GridBase &grid);
+
 VolumeGridType BKE_volume_grid_type_openvdb(const openvdb::GridBase &grid);
 
 template
diff --git a/source/blender/blenkernel/BKE_writeffmpeg.h b/source/blender/blenkernel/BKE_writeffmpeg.h
index 3f92d6fa117..736f7548bb4 100644
--- a/source/blender/blenkernel/BKE_writeffmpeg.h
+++ b/source/blender/blenkernel/BKE_writeffmpeg.h
@@ -68,7 +68,7 @@ void BKE_ffmpeg_filepath_get(char *string,
                              const char *suffix);
 
 void BKE_ffmpeg_preset_set(struct RenderData *rd, int preset);
-void BKE_ffmpeg_image_type_verify(struct RenderData *rd, struct ImageFormatData *imf);
+void BKE_ffmpeg_image_type_verify(struct RenderData *rd, const struct ImageFormatData *imf);
 bool BKE_ffmpeg_alpha_channel_is_supported(const struct RenderData *rd);
 
 void *BKE_ffmpeg_context_create(void);
diff --git a/source/blender/blenkernel/CMakeLists.txt b/source/blender/blenkernel/CMakeLists.txt
index 14e3856f93d..88df849ae61 100644
--- a/source/blender/blenkernel/CMakeLists.txt
+++ b/source/blender/blenkernel/CMakeLists.txt
@@ -25,7 +25,6 @@ set(INC
   ../simulation
   ../../../intern/eigen
   ../../../intern/ghost
-  ../../../intern/glew-mx
   ../../../intern/guardedalloc
   ../../../intern/iksolver/extern
   ../../../intern/atomic
@@ -99,9 +98,10 @@ set(SRC
   intern/collision.c
   intern/colorband.c
   intern/colortools.c
+  intern/compute_contexts.cc
   intern/constraint.c
   intern/context.c
-  intern/crazyspace.c
+  intern/crazyspace.cc
   intern/cryptomatte.cc
   intern/curve.cc
   intern/curve_bevel.c
@@ -110,7 +110,6 @@ set(SRC
   intern/curve_convert.c
   intern/curve_decimate.c
   intern/curve_deform.c
-  intern/curve_eval.cc
   intern/curve_legacy_convert.cc
   intern/curve_nurbs.cc
   intern/curve_poly.cc
@@ -129,7 +128,7 @@ set(SRC
   intern/editmesh.c
   intern/editmesh_bvh.c
   intern/editmesh_cache.cc
-  intern/editmesh_tangent.c
+  intern/editmesh_tangent.cc
   intern/effect.c
   intern/fcurve.c
   intern/fcurve_cache.c
@@ -137,12 +136,13 @@ set(SRC
   intern/fluid.c
   intern/fmodifier.c
   intern/freestyle.c
-  intern/geometry_component_curve.cc
   intern/geometry_component_curves.cc
+  intern/geometry_component_edit_data.cc
   intern/geometry_component_instances.cc
   intern/geometry_component_mesh.cc
   intern/geometry_component_pointcloud.cc
   intern/geometry_component_volume.cc
+  intern/geometry_fields.cc
   intern/geometry_set.cc
   intern/geometry_set_instances.cc
   intern/gpencil.c
@@ -185,11 +185,12 @@ set(SRC
   intern/linestyle.c
   intern/main.c
   intern/main_idmap.c
+  intern/main_namemap.cc
   intern/mask.c
   intern/mask_evaluate.c
   intern/mask_rasterize.c
   intern/material.c
-  intern/mball.c
+  intern/mball.cc
   intern/mball_tessellate.c
   intern/mesh.cc
   intern/mesh_boolean_convert.cc
@@ -200,7 +201,7 @@ set(SRC
   intern/mesh_fair.cc
   intern/mesh_iterators.c
   intern/mesh_legacy_convert.cc
-  intern/mesh_mapping.c
+  intern/mesh_mapping.cc
   intern/mesh_merge.c
   intern/mesh_merge_customdata.cc
   intern/mesh_mirror.c
@@ -209,8 +210,8 @@ set(SRC
   intern/mesh_remesh_voxel.cc
   intern/mesh_runtime.cc
   intern/mesh_sample.cc
-  intern/mesh_tangent.c
-  intern/mesh_tessellate.c
+  intern/mesh_tangent.cc
+  intern/mesh_tessellate.cc
   intern/mesh_validate.cc
   intern/mesh_wrapper.cc
   intern/modifier.c
@@ -228,6 +229,7 @@ set(SRC
   intern/multires_versioning.c
   intern/nla.c
   intern/node.cc
+  intern/node_runtime.cc
   intern/node_tree_update.cc
   intern/object.cc
   intern/object_deform.c
@@ -236,9 +238,9 @@ set(SRC
   intern/object_update.c
   intern/ocean.c
   intern/ocean_spectrum.c
-  intern/outliner_treehash.c
+  intern/outliner_treehash.cc
   intern/packedFile.c
-  intern/paint.c
+  intern/paint.cc
   intern/paint_canvas.cc
   intern/paint_toolslots.c
   intern/particle.c
@@ -262,10 +264,6 @@ set(SRC
   intern/softbody.c
   intern/sound.c
   intern/speaker.c
-  intern/spline_base.cc
-  intern/spline_bezier.cc
-  intern/spline_nurbs.cc
-  intern/spline_poly.cc
   intern/studiolight.c
   intern/subdiv.c
   intern/subdiv_ccg.c
@@ -278,7 +276,7 @@ set(SRC
   intern/subdiv_displacement_multires.c
   intern/subdiv_eval.c
   intern/subdiv_foreach.c
-  intern/subdiv_mesh.c
+  intern/subdiv_mesh.cc
   intern/subdiv_modifier.c
   intern/subdiv_stats.c
   intern/subdiv_topology.c
@@ -302,7 +300,7 @@ set(SRC
   intern/volume.cc
   intern/volume_render.cc
   intern/volume_to_mesh.cc
-  intern/workspace.c
+  intern/workspace.cc
   intern/world.c
   intern/writeavi.c
 
@@ -349,9 +347,11 @@ set(SRC
   BKE_collision.h
   BKE_colorband.h
   BKE_colortools.h
+  BKE_compute_contexts.hh
   BKE_constraint.h
   BKE_context.h
   BKE_crazyspace.h
+  BKE_crazyspace.hh
   BKE_cryptomatte.h
   BKE_cryptomatte.hh
   BKE_curve.h
@@ -396,6 +396,7 @@ set(SRC
   BKE_image_format.h
   BKE_image_partial_update.hh
   BKE_image_save.h
+  BKE_image_wrappers.hh
   BKE_ipo.h
   BKE_kelvinlet.h
   BKE_key.h
@@ -412,6 +413,7 @@ set(SRC
   BKE_linestyle.h
   BKE_main.h
   BKE_main_idmap.h
+  BKE_main_namemap.h
   BKE_mask.h
   BKE_material.h
   BKE_mball.h
@@ -441,11 +443,12 @@ set(SRC
   BKE_object_deform.h
   BKE_object_facemap.h
   BKE_ocean.h
-  BKE_outliner_treehash.h
+  BKE_outliner_treehash.hh
   BKE_packedFile.h
   BKE_paint.h
   BKE_particle.h
   BKE_pbvh.h
+  BKE_pbvh_pixels.hh
   BKE_pointcache.h
   BKE_pointcloud.h
   BKE_preferences.h
@@ -460,7 +463,6 @@ set(SRC
   BKE_softbody.h
   BKE_sound.h
   BKE_speaker.h
-  BKE_spline.hh
   BKE_studiolight.h
   BKE_subdiv.h
   BKE_subdiv_ccg.h
@@ -652,6 +654,10 @@ if(WITH_PYTHON)
   )
   add_definitions(-DWITH_PYTHON)
 
+  if(WITH_PYTHON_MODULE)
+    add_definitions(-DWITH_PYTHON_MODULE)
+  endif()
+
   if(WITH_PYTHON_SAFETY)
     add_definitions(-DWITH_PYTHON_SAFETY)
   endif()
diff --git a/source/blender/blenkernel/intern/DerivedMesh.cc b/source/blender/blenkernel/intern/DerivedMesh.cc
index c2ea01bcadf..3aeb2a17b3c 100644
--- a/source/blender/blenkernel/intern/DerivedMesh.cc
+++ b/source/blender/blenkernel/intern/DerivedMesh.cc
@@ -68,6 +68,8 @@
 
 using blender::float3;
 using blender::IndexRange;
+using blender::Span;
+using blender::VArray;
 
 /* very slow! enable for testing only! */
 //#define USE_MODIFIER_VALIDATE
@@ -84,6 +86,8 @@ static ThreadRWMutex loops_cache_lock = PTHREAD_RWLOCK_INITIALIZER;
 static void mesh_init_origspace(Mesh *mesh);
 static void editbmesh_calc_modifier_final_normals(Mesh *mesh_final,
                                                   const CustomData_MeshMasks *final_datamask);
+static void editbmesh_calc_modifier_final_normals_or_defer(
+    Mesh *mesh_final, const CustomData_MeshMasks *final_datamask);
 
 /* -------------------------------------------------------------------- */
 
@@ -93,7 +97,7 @@ static MVert *dm_getVertArray(DerivedMesh *dm)
 
   if (!mvert) {
     mvert = (MVert *)CustomData_add_layer(
-        &dm->vertData, CD_MVERT, CD_CALLOC, nullptr, dm->getNumVerts(dm));
+        &dm->vertData, CD_MVERT, CD_SET_DEFAULT, nullptr, dm->getNumVerts(dm));
     CustomData_set_layer_flag(&dm->vertData, CD_MVERT, CD_FLAG_TEMPORARY);
     dm->copyVertArray(dm, mvert);
   }
@@ -107,7 +111,7 @@ static MEdge *dm_getEdgeArray(DerivedMesh *dm)
 
   if (!medge) {
     medge = (MEdge *)CustomData_add_layer(
-        &dm->edgeData, CD_MEDGE, CD_CALLOC, nullptr, dm->getNumEdges(dm));
+        &dm->edgeData, CD_MEDGE, CD_SET_DEFAULT, nullptr, dm->getNumEdges(dm));
     CustomData_set_layer_flag(&dm->edgeData, CD_MEDGE, CD_FLAG_TEMPORARY);
     dm->copyEdgeArray(dm, medge);
   }
@@ -121,7 +125,7 @@ static MLoop *dm_getLoopArray(DerivedMesh *dm)
 
   if (!mloop) {
     mloop = (MLoop *)CustomData_add_layer(
-        &dm->loopData, CD_MLOOP, CD_CALLOC, nullptr, dm->getNumLoops(dm));
+        &dm->loopData, CD_MLOOP, CD_SET_DEFAULT, nullptr, dm->getNumLoops(dm));
     CustomData_set_layer_flag(&dm->loopData, CD_MLOOP, CD_FLAG_TEMPORARY);
     dm->copyLoopArray(dm, mloop);
   }
@@ -135,7 +139,7 @@ static MPoly *dm_getPolyArray(DerivedMesh *dm)
 
   if (!mpoly) {
     mpoly = (MPoly *)CustomData_add_layer(
-        &dm->polyData, CD_MPOLY, CD_CALLOC, nullptr, dm->getNumPolys(dm));
+        &dm->polyData, CD_MPOLY, CD_SET_DEFAULT, nullptr, dm->getNumPolys(dm));
     CustomData_set_layer_flag(&dm->polyData, CD_MPOLY, CD_FLAG_TEMPORARY);
     dm->copyPolyArray(dm, mpoly);
   }
@@ -143,54 +147,6 @@ static MPoly *dm_getPolyArray(DerivedMesh *dm)
   return mpoly;
 }
 
-static MVert *dm_dupVertArray(DerivedMesh *dm)
-{
-  MVert *tmp = (MVert *)MEM_malloc_arrayN(
-      dm->getNumVerts(dm), sizeof(*tmp), "dm_dupVertArray tmp");
-
-  if (tmp) {
-    dm->copyVertArray(dm, tmp);
-  }
-
-  return tmp;
-}
-
-static MEdge *dm_dupEdgeArray(DerivedMesh *dm)
-{
-  MEdge *tmp = (MEdge *)MEM_malloc_arrayN(
-      dm->getNumEdges(dm), sizeof(*tmp), "dm_dupEdgeArray tmp");
-
-  if (tmp) {
-    dm->copyEdgeArray(dm, tmp);
-  }
-
-  return tmp;
-}
-
-static MLoop *dm_dupLoopArray(DerivedMesh *dm)
-{
-  MLoop *tmp = (MLoop *)MEM_malloc_arrayN(
-      dm->getNumLoops(dm), sizeof(*tmp), "dm_dupLoopArray tmp");
-
-  if (tmp) {
-    dm->copyLoopArray(dm, tmp);
-  }
-
-  return tmp;
-}
-
-static MPoly *dm_dupPolyArray(DerivedMesh *dm)
-{
-  MPoly *tmp = (MPoly *)MEM_malloc_arrayN(
-      dm->getNumPolys(dm), sizeof(*tmp), "dm_dupPolyArray tmp");
-
-  if (tmp) {
-    dm->copyPolyArray(dm, tmp);
-  }
-
-  return tmp;
-}
-
 static int dm_getNumLoopTri(DerivedMesh *dm)
 {
   const int numlooptris = poly_to_tri_count(dm->getNumPolys(dm), dm->getNumLoops(dm));
@@ -229,14 +185,10 @@ void DM_init_funcs(DerivedMesh *dm)
   dm->getEdgeArray = dm_getEdgeArray;
   dm->getLoopArray = dm_getLoopArray;
   dm->getPolyArray = dm_getPolyArray;
-  dm->dupVertArray = dm_dupVertArray;
-  dm->dupEdgeArray = dm_dupEdgeArray;
-  dm->dupLoopArray = dm_dupLoopArray;
-  dm->dupPolyArray = dm_dupPolyArray;
 
   dm->getLoopTriArray = dm_getLoopTriArray;
 
-  /* subtypes handle getting actual data */
+  /* Sub-types handle getting actual data. */
   dm->getNumLoopTri = dm_getNumLoopTri;
 
   dm->getVertDataArray = DM_get_vert_data_layer;
@@ -282,11 +234,11 @@ void DM_from_template(DerivedMesh *dm,
                       int numPolys)
 {
   const CustomData_MeshMasks *mask = &CD_MASK_DERIVEDMESH;
-  CustomData_copy(&source->vertData, &dm->vertData, mask->vmask, CD_CALLOC, numVerts);
-  CustomData_copy(&source->edgeData, &dm->edgeData, mask->emask, CD_CALLOC, numEdges);
-  CustomData_copy(&source->faceData, &dm->faceData, mask->fmask, CD_CALLOC, numTessFaces);
-  CustomData_copy(&source->loopData, &dm->loopData, mask->lmask, CD_CALLOC, numLoops);
-  CustomData_copy(&source->polyData, &dm->polyData, mask->pmask, CD_CALLOC, numPolys);
+  CustomData_copy(&source->vertData, &dm->vertData, mask->vmask, CD_SET_DEFAULT, numVerts);
+  CustomData_copy(&source->edgeData, &dm->edgeData, mask->emask, CD_SET_DEFAULT, numEdges);
+  CustomData_copy(&source->faceData, &dm->faceData, mask->fmask, CD_SET_DEFAULT, numTessFaces);
+  CustomData_copy(&source->loopData, &dm->loopData, mask->lmask, CD_SET_DEFAULT, numLoops);
+  CustomData_copy(&source->polyData, &dm->polyData, mask->pmask, CD_SET_DEFAULT, numPolys);
 
   dm->cd_flag = source->cd_flag;
 
@@ -327,36 +279,6 @@ bool DM_release(DerivedMesh *dm)
   return false;
 }
 
-void DM_DupPolys(DerivedMesh *source, DerivedMesh *target)
-{
-  CustomData_free(&target->loopData, source->numLoopData);
-  CustomData_free(&target->polyData, source->numPolyData);
-
-  CustomData_copy(&source->loopData,
-                  &target->loopData,
-                  CD_MASK_DERIVEDMESH.lmask,
-                  CD_DUPLICATE,
-                  source->numLoopData);
-  CustomData_copy(&source->polyData,
-                  &target->polyData,
-                  CD_MASK_DERIVEDMESH.pmask,
-                  CD_DUPLICATE,
-                  source->numPolyData);
-
-  target->numLoopData = source->numLoopData;
-  target->numPolyData = source->numPolyData;
-
-  if (!CustomData_has_layer(&target->polyData, CD_MPOLY)) {
-    MPoly *mpoly;
-    MLoop *mloop;
-
-    mloop = source->dupLoopArray(source);
-    mpoly = source->dupPolyArray(source);
-    CustomData_add_layer(&target->loopData, CD_MLOOP, CD_ASSIGN, mloop, source->numLoopData);
-    CustomData_add_layer(&target->polyData, CD_MPOLY, CD_ASSIGN, mpoly, source->numPolyData);
-  }
-}
-
 void DM_ensure_looptri_data(DerivedMesh *dm)
 {
   const unsigned int totpoly = dm->numPolyData;
@@ -582,8 +504,7 @@ static void add_orco_mesh(Object *ob, BMEditMesh *em, Mesh *mesh, Mesh *mesh_orc
     }
 
     if (!(layerorco = (float(*)[3])CustomData_get_layer(&mesh->vdata, layer))) {
-      CustomData_add_layer(&mesh->vdata, layer, CD_CALLOC, nullptr, mesh->totvert);
-      BKE_mesh_update_customdata_pointers(mesh, false);
+      CustomData_add_layer(&mesh->vdata, layer, CD_SET_DEFAULT, nullptr, mesh->totvert);
 
       layerorco = (float(*)[3])CustomData_get_layer(&mesh->vdata, layer);
     }
@@ -663,8 +584,8 @@ static void mesh_calc_finalize(const Mesh *mesh_input, Mesh *mesh_eval)
   mesh_eval->edit_mesh = mesh_input->edit_mesh;
 }
 
-void BKE_mesh_wrapper_deferred_finalize(Mesh *me_eval,
-                                        const CustomData_MeshMasks *cd_mask_finalize)
+void BKE_mesh_wrapper_deferred_finalize_mdata(Mesh *me_eval,
+                                              const CustomData_MeshMasks *cd_mask_finalize)
 {
   if (me_eval->runtime.wrapper_type_finalize & (1 << ME_WRAPPER_TYPE_BMESH)) {
     editbmesh_calc_modifier_final_normals(me_eval, cd_mask_finalize);
@@ -739,6 +660,7 @@ static void mesh_calc_modifiers(struct Depsgraph *depsgraph,
                                 Mesh **r_final,
                                 GeometrySet **r_geometry_set)
 {
+  using namespace blender::bke;
   /* Input and final mesh. Final mesh is only created the moment the first
    * constructive modifier is executed, or a deform modifier needs normals
    * or certain data layers. */
@@ -809,7 +731,7 @@ static void mesh_calc_modifiers(struct Depsgraph *depsgraph,
    * subdividing them is expensive. */
   CustomData_MeshMasks final_datamask = *dataMask;
   CDMaskLink *datamasks = BKE_modifier_calc_data_masks(
-      scene, ob, md, &final_datamask, required_mode, previewmd, &previewmask);
+      scene, md, &final_datamask, required_mode, previewmd, &previewmask);
   CDMaskLink *md_datamask = datamasks;
   /* XXX Always copying POLYINDEX, else tessellated data are no more valid! */
   CustomData_MeshMasks append_mask = CD_MASK_BAREMESH_ORIGINDEX;
@@ -822,18 +744,13 @@ static void mesh_calc_modifiers(struct Depsgraph *depsgraph,
       mesh_final = BKE_mesh_copy_for_eval(mesh_input, true);
       ASSERT_IS_VALID_MESH(mesh_final);
     }
-    float3 *rest_positions = static_cast(CustomData_add_layer_named(&mesh_final->vdata,
-                                                                              CD_PROP_FLOAT3,
-                                                                              CD_DEFAULT,
-                                                                              nullptr,
-                                                                              mesh_final->totvert,
-                                                                              "rest_position"));
-    blender::threading::parallel_for(
-        IndexRange(mesh_final->totvert), 1024, [&](const IndexRange range) {
-          for (const int i : range) {
-            rest_positions[i] = mesh_final->mvert[i].co;
-          }
-        });
+    MutableAttributeAccessor attributes = mesh_final->attributes_for_write();
+    SpanAttributeWriter rest_positions =
+        attributes.lookup_or_add_for_write_only_span("rest_position", ATTR_DOMAIN_POINT);
+    if (rest_positions) {
+      attributes.lookup("position").materialize(rest_positions.span);
+      rest_positions.finish();
+    }
   }
 
   /* Apply all leading deform modifiers. */
@@ -935,7 +852,7 @@ static void mesh_calc_modifiers(struct Depsgraph *depsgraph,
     /* Add orco mesh as layer if needed by this modifier. */
     if (mesh_final && mesh_orco && mti->requiredDataMask) {
       CustomData_MeshMasks mask = {0};
-      mti->requiredDataMask(ob, md, &mask);
+      mti->requiredDataMask(md, &mask);
       if (mask.vmask & CD_MASK_ORCO) {
         add_orco_mesh(ob, nullptr, mesh_final, mesh_orco, CD_ORCO);
       }
@@ -1005,11 +922,11 @@ static void mesh_calc_modifiers(struct Depsgraph *depsgraph,
             ((nextmask.vmask | nextmask.emask | nextmask.pmask) & CD_MASK_ORIGINDEX)) {
           /* calc */
           CustomData_add_layer(
-              &mesh_final->vdata, CD_ORIGINDEX, CD_CALLOC, nullptr, mesh_final->totvert);
+              &mesh_final->vdata, CD_ORIGINDEX, CD_CONSTRUCT, nullptr, mesh_final->totvert);
           CustomData_add_layer(
-              &mesh_final->edata, CD_ORIGINDEX, CD_CALLOC, nullptr, mesh_final->totedge);
+              &mesh_final->edata, CD_ORIGINDEX, CD_CONSTRUCT, nullptr, mesh_final->totedge);
           CustomData_add_layer(
-              &mesh_final->pdata, CD_ORIGINDEX, CD_CALLOC, nullptr, mesh_final->totpoly);
+              &mesh_final->pdata, CD_ORIGINDEX, CD_CONSTRUCT, nullptr, mesh_final->totpoly);
 
           /* Not worth parallelizing this,
            * gives less than 0.1% overall speedup in best of best cases... */
@@ -1045,8 +962,11 @@ static void mesh_calc_modifiers(struct Depsgraph *depsgraph,
       /* add an origspace layer if needed */
       if ((md_datamask->mask.lmask) & CD_MASK_ORIGSPACE_MLOOP) {
         if (!CustomData_has_layer(&mesh_final->ldata, CD_ORIGSPACE_MLOOP)) {
-          CustomData_add_layer(
-              &mesh_final->ldata, CD_ORIGSPACE_MLOOP, CD_CALLOC, nullptr, mesh_final->totloop);
+          CustomData_add_layer(&mesh_final->ldata,
+                               CD_ORIGSPACE_MLOOP,
+                               CD_SET_DEFAULT,
+                               nullptr,
+                               mesh_final->totloop);
           mesh_init_origspace(mesh_final);
         }
       }
@@ -1083,7 +1003,7 @@ static void mesh_calc_modifiers(struct Depsgraph *depsgraph,
         temp_cddata_masks.pmask = CD_MASK_ORIGINDEX;
 
         if (mti->requiredDataMask != nullptr) {
-          mti->requiredDataMask(ob, md, &temp_cddata_masks);
+          mti->requiredDataMask(md, &temp_cddata_masks);
         }
         CustomData_MeshMasks_update(&temp_cddata_masks, &nextmask);
         mesh_set_only_copy(mesh_orco, &temp_cddata_masks);
@@ -1286,12 +1206,6 @@ bool editbmesh_modifier_is_enabled(const Scene *scene,
 static void editbmesh_calc_modifier_final_normals(Mesh *mesh_final,
                                                   const CustomData_MeshMasks *final_datamask)
 {
-  if (mesh_final->runtime.wrapper_type != ME_WRAPPER_TYPE_MDATA) {
-    /* Generated at draw time. */
-    mesh_final->runtime.wrapper_type_finalize = (1 << mesh_final->runtime.wrapper_type);
-    return;
-  }
-
   const bool calc_loop_normals = ((mesh_final->flag & ME_AUTOSMOOTH) != 0 ||
                                   (final_datamask->lmask & CD_MASK_NORMAL) != 0);
 
@@ -1319,6 +1233,18 @@ static void editbmesh_calc_modifier_final_normals(Mesh *mesh_final,
   }
 }
 
+static void editbmesh_calc_modifier_final_normals_or_defer(
+    Mesh *mesh_final, const CustomData_MeshMasks *final_datamask)
+{
+  if (mesh_final->runtime.wrapper_type != ME_WRAPPER_TYPE_MDATA) {
+    /* Generated at draw time. */
+    mesh_final->runtime.wrapper_type_finalize = (1 << mesh_final->runtime.wrapper_type);
+    return;
+  }
+
+  editbmesh_calc_modifier_final_normals(mesh_final, final_datamask);
+}
+
 static void editbmesh_calc_modifiers(struct Depsgraph *depsgraph,
                                      const Scene *scene,
                                      Object *ob,
@@ -1372,7 +1298,7 @@ static void editbmesh_calc_modifiers(struct Depsgraph *depsgraph,
    * subdividing them is expensive. */
   CustomData_MeshMasks final_datamask = *dataMask;
   CDMaskLink *datamasks = BKE_modifier_calc_data_masks(
-      scene, ob, md, &final_datamask, required_mode, nullptr, nullptr);
+      scene, md, &final_datamask, required_mode, nullptr, nullptr);
   CDMaskLink *md_datamask = datamasks;
   CustomData_MeshMasks append_mask = CD_MASK_BAREMESH;
 
@@ -1402,7 +1328,7 @@ static void editbmesh_calc_modifiers(struct Depsgraph *depsgraph,
     /* Add an orco mesh as layer if needed by this modifier. */
     if (mesh_final && mesh_orco && mti->requiredDataMask) {
       CustomData_MeshMasks mask = {0};
-      mti->requiredDataMask(ob, md, &mask);
+      mti->requiredDataMask(md, &mask);
       if (mask.vmask & CD_MASK_ORCO) {
         add_orco_mesh(ob, em_input, mesh_final, mesh_orco, CD_ORCO);
       }
@@ -1502,8 +1428,11 @@ static void editbmesh_calc_modifiers(struct Depsgraph *depsgraph,
 
       if (mask.lmask & CD_MASK_ORIGSPACE_MLOOP) {
         if (!CustomData_has_layer(&mesh_final->ldata, CD_ORIGSPACE_MLOOP)) {
-          CustomData_add_layer(
-              &mesh_final->ldata, CD_ORIGSPACE_MLOOP, CD_CALLOC, nullptr, mesh_final->totloop);
+          CustomData_add_layer(&mesh_final->ldata,
+                               CD_ORIGSPACE_MLOOP,
+                               CD_SET_DEFAULT,
+                               nullptr,
+                               mesh_final->totloop);
           mesh_init_origspace(mesh_final);
         }
       }
@@ -1562,11 +1491,9 @@ static void editbmesh_calc_modifiers(struct Depsgraph *depsgraph,
    * then we need to build one. */
   if (mesh_final) {
     if (deformed_verts) {
-      Mesh *mesh_tmp = BKE_mesh_copy_for_eval(mesh_final, false);
-      if (mesh_final != mesh_cage) {
-        BKE_id_free(nullptr, mesh_final);
+      if (mesh_final == mesh_cage) {
+        mesh_final = BKE_mesh_copy_for_eval(mesh_final, false);
       }
-      mesh_final = mesh_tmp;
       BKE_mesh_vert_coords_apply(mesh_final, deformed_verts);
     }
   }
@@ -1587,7 +1514,7 @@ static void editbmesh_calc_modifiers(struct Depsgraph *depsgraph,
 
   /* Add orco coordinates to final and deformed mesh if requested. */
   if (final_datamask.vmask & CD_MASK_ORCO) {
-    /* FIXME(Campbell): avoid the need to convert to mesh data just to add an orco layer. */
+    /* FIXME(@campbellbarton): avoid the need to convert to mesh data just to add an orco layer. */
     BKE_mesh_wrapper_ensure_mdata(mesh_final);
 
     add_orco_mesh(ob, em_input, mesh_final, mesh_orco, CD_ORCO);
@@ -1598,9 +1525,9 @@ static void editbmesh_calc_modifiers(struct Depsgraph *depsgraph,
   }
 
   /* Compute normals. */
-  editbmesh_calc_modifier_final_normals(mesh_final, &final_datamask);
+  editbmesh_calc_modifier_final_normals_or_defer(mesh_final, &final_datamask);
   if (mesh_cage && (mesh_cage != mesh_final)) {
-    editbmesh_calc_modifier_final_normals(mesh_cage, &final_datamask);
+    editbmesh_calc_modifier_final_normals_or_defer(mesh_cage, &final_datamask);
   }
 
   /* Return final mesh. */
@@ -1735,6 +1662,7 @@ static void object_get_datamask(const Depsgraph *depsgraph,
                                 CustomData_MeshMasks *r_mask,
                                 bool *r_need_mapping)
 {
+  Scene *scene = DEG_get_evaluated_scene(depsgraph);
   ViewLayer *view_layer = DEG_get_evaluated_view_layer(depsgraph);
 
   DEG_get_customdata_mask_for_object(depsgraph, ob, r_mask);
@@ -1749,8 +1677,11 @@ static void object_get_datamask(const Depsgraph *depsgraph,
     return;
   }
 
-  Object *actob = view_layer->basact ? DEG_get_original_object(view_layer->basact->object) :
-                                       nullptr;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *actob = BKE_view_layer_active_object_get(view_layer);
+  if (actob) {
+    actob = DEG_get_original_object(actob);
+  }
   if (DEG_get_original_object(ob) == actob) {
     bool editing = BKE_paint_select_face_test(actob);
 
@@ -1793,7 +1724,7 @@ void makeDerivedMesh(struct Depsgraph *depsgraph,
 
   BKE_object_free_derived_caches(ob);
   if (DEG_is_active(depsgraph)) {
-    BKE_sculpt_update_object_before_eval(scene, ob);
+    BKE_sculpt_update_object_before_eval(ob);
   }
 
   /* NOTE: Access the `edit_mesh` after freeing the derived caches, so that `ob->data` is restored
@@ -1994,9 +1925,9 @@ void mesh_get_mapped_verts_coords(Mesh *me_eval, float (*r_cos)[3], const int to
     MEM_freeN(userData.vertex_visit);
   }
   else {
-    MVert *mv = me_eval->mvert;
-    for (int i = 0; i < totcos; i++, mv++) {
-      copy_v3_v3(r_cos[i], mv->co);
+    const Span verts = me_eval->verts();
+    for (int i = 0; i < totcos; i++) {
+      copy_v3_v3(r_cos[i], verts[i].co);
     }
   }
 }
@@ -2009,9 +1940,11 @@ static void mesh_init_origspace(Mesh *mesh)
                                                                    CD_ORIGSPACE_MLOOP);
   const int numpoly = mesh->totpoly;
   // const int numloop = mesh->totloop;
-  MVert *mv = mesh->mvert;
-  MLoop *ml = mesh->mloop;
-  MPoly *mp = mesh->mpoly;
+  const Span verts = mesh->verts();
+  const Span polys = mesh->polys();
+  const Span loops = mesh->loops();
+
+  const MPoly *mp = polys.data();
   int i, j, k;
 
   blender::Vector vcos_2d;
@@ -2025,19 +1958,19 @@ static void mesh_init_origspace(Mesh *mesh)
       }
     }
     else {
-      MLoop *l = &ml[mp->loopstart];
+      const MLoop *l = &loops[mp->loopstart];
       float p_nor[3], co[3];
       float mat[3][3];
 
       float min[2] = {FLT_MAX, FLT_MAX}, max[2] = {-FLT_MAX, -FLT_MAX};
       float translate[2], scale[2];
 
-      BKE_mesh_calc_poly_normal(mp, l, mv, p_nor);
+      BKE_mesh_calc_poly_normal(mp, l, verts.data(), p_nor);
       axis_dominant_v3_to_m3(mat, p_nor);
 
       vcos_2d.resize(mp->totloop);
       for (j = 0; j < mp->totloop; j++, l++) {
-        mul_v3_m3v3(co, mat, mv[l->v].co);
+        mul_v3_m3v3(co, mat, verts[l->v].co);
         copy_v2_v2(vcos_2d[j], co);
 
         for (k = 0; k < 2; k++) {
diff --git a/source/blender/blenkernel/intern/action.c b/source/blender/blenkernel/intern/action.c
index fee7582acb3..10aa4ec7906 100644
--- a/source/blender/blenkernel/intern/action.c
+++ b/source/blender/blenkernel/intern/action.c
@@ -53,6 +53,7 @@
 #include "BIK_api.h"
 
 #include "RNA_access.h"
+#include "RNA_path.h"
 #include "RNA_prototypes.h"
 
 #include "BLO_read_write.h"
@@ -112,7 +113,7 @@ static void action_copy_data(Main *UNUSED(bmain), ID *id_dst, const ID *id_src,
 
     BLI_addtail(&action_dst->curves, fcurve_dst);
 
-    /* Fix group links (kindof bad list-in-list search, but this is the most reliable way). */
+    /* Fix group links (kind of bad list-in-list search, but this is the most reliable way). */
     for (group_dst = action_dst->groups.first, group_src = action_src->groups.first;
          group_dst && group_src;
          group_dst = group_dst->next, group_src = group_src->next) {
@@ -314,7 +315,7 @@ IDTypeInfo IDType_ID_AC = {
     .foreach_id = action_foreach_id,
     .foreach_cache = NULL,
     .foreach_path = NULL,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = action_blend_write,
     .blend_read_data = action_blend_read_data,
@@ -1950,7 +1951,7 @@ void BKE_pose_blend_read_lib(BlendLibReader *reader, Object *ob, bPose *pose)
 
     pchan->bone = BKE_armature_find_bone_name(arm, pchan->name);
 
-    IDP_BlendReadLib(reader, pchan->prop);
+    IDP_BlendReadLib(reader, ob->id.lib, pchan->prop);
 
     BLO_read_id_address(reader, ob->id.lib, &pchan->custom);
     if (UNLIKELY(pchan->bone == NULL)) {
diff --git a/source/blender/blenkernel/intern/action_mirror.c b/source/blender/blenkernel/intern/action_mirror.c
index 7ef561c8216..0663538f3bb 100644
--- a/source/blender/blenkernel/intern/action_mirror.c
+++ b/source/blender/blenkernel/intern/action_mirror.c
@@ -363,7 +363,7 @@ static void action_flip_pchan(Object *ob_arm,
 
   /* Recalculate handles. */
   for (int i = 0; i < fcurve_array_len; i++) {
-    calchandles_fcurve_ex(fcurve_array[i], 0);
+    BKE_fcurve_handles_recalc_ex(fcurve_array[i], 0);
   }
 
   MEM_freeN((void *)keyed_frames);
diff --git a/source/blender/blenkernel/intern/anim_data.c b/source/blender/blenkernel/intern/anim_data.c
index 861a89ea9d7..65ce3e3b523 100644
--- a/source/blender/blenkernel/intern/anim_data.c
+++ b/source/blender/blenkernel/intern/anim_data.c
@@ -43,6 +43,7 @@
 #include "BLO_read_write.h"
 
 #include "RNA_access.h"
+#include "RNA_path.h"
 
 #include "CLG_log.h"
 
@@ -135,7 +136,7 @@ bool BKE_animdata_set_action(ReportList *reports, ID *id, bAction *act)
     return false;
   }
 
-  /* Reduce usercount for current action. */
+  /* Reduce user-count for current action. */
   if (adt->action) {
     id_us_min((ID *)adt->action);
   }
@@ -286,11 +287,11 @@ AnimData *BKE_animdata_copy(Main *bmain, AnimData *adt, const int flag)
 
   /* make a copy of action - at worst, user has to delete copies... */
   if (do_action) {
-    /* Recursive copy of 'real' IDs is a bit hairy. Even if do not want to deal with usercount
-     *  when copying ID's data itself, we still need to do so with sub-IDs, since those will not be
-     * handled by later 'update usercounts of used IDs' code as used e.g. at end of
-     * BKE_id_copy_ex().
-     * So in case we do copy the ID and its sub-IDs in bmain, silence the 'no usercount' flag for
+    /* Recursive copy of 'real' IDs is a bit hairy. Even if do not want to deal with user-count
+     * when copying ID's data itself, we still need to do so with sub-IDs, since those will not be
+     * handled by later 'update user-counts of used IDs' code as used e.g. at end of
+     * #BKE_id_copy_ex().
+     * So in case we do copy the ID and its sub-IDs in bmain, silence the 'no user-count' flag for
      * the sub-IDs copying.
      * NOTE: This is a bit weak, as usually when it comes to recursive ID copy. Should work for
      * now, but we may have to revisit this at some point and add a proper extra flag to deal with
diff --git a/source/blender/blenkernel/intern/anim_sys.c b/source/blender/blenkernel/intern/anim_sys.c
index eb4784bebff..85ce647fcab 100644
--- a/source/blender/blenkernel/intern/anim_sys.c
+++ b/source/blender/blenkernel/intern/anim_sys.c
@@ -53,6 +53,7 @@
 #include "DEG_depsgraph_query.h"
 
 #include "RNA_access.h"
+#include "RNA_path.h"
 #include "RNA_prototypes.h"
 
 #include "BLO_read_write.h"
@@ -3623,16 +3624,6 @@ void nlasnapshot_blend_get_inverted_upper_snapshot(NlaEvalData *eval_data,
   }
 }
 
-/** Using \a blended_snapshot and \a upper_snapshot, we can solve for the \a r_lower_snapshot.
- *
- * Only channels that exist within \a blended_snapshot are processed.
- * Only blended values within the \a remap_domain are processed.
- *
- * Writes to \a r_upper_snapshot NlaEvalChannelSnapshot->remap_domain to match remapping success.
- *
- * Assumes caller marked upper values that are in the \a blend_domain. This determines whether the
- * blended value came directly from the lower snapshot or a result of blending.
- **/
 void nlasnapshot_blend_get_inverted_lower_snapshot(NlaEvalData *eval_data,
                                                    NlaEvalSnapshot *blended_snapshot,
                                                    NlaEvalSnapshot *upper_snapshot,
diff --git a/source/blender/blenkernel/intern/appdir.c b/source/blender/blenkernel/intern/appdir.c
index 031d3647878..e3c42c8bb78 100644
--- a/source/blender/blenkernel/intern/appdir.c
+++ b/source/blender/blenkernel/intern/appdir.c
@@ -371,14 +371,16 @@ static bool get_path_local_ex(char *targetpath,
     relfolder[0] = '\0';
   }
 
-  /* Try `{g_app.program_dirname}/2.xx/{folder_name}` the default directory
+  /* Try `{g_app.program_dirname}/3.xx/{folder_name}` the default directory
    * for a portable distribution. See `WITH_INSTALL_PORTABLE` build-option. */
   const char *path_base = g_app.program_dirname;
-#ifdef __APPLE__
+#if defined(__APPLE__) && !defined(WITH_PYTHON_MODULE)
   /* Due new code-sign situation in OSX > 10.9.5
-   * we must move the blender_version dir with contents to Resources. */
-  char osx_resourses[FILE_MAX];
-  BLI_snprintf(osx_resourses, sizeof(osx_resourses), "%s../Resources", g_app.program_dirname);
+   * we must move the blender_version dir with contents to Resources.
+   * Add 4 + 9 for the temporary `/../` path & `Resources`. */
+  char osx_resourses[FILE_MAX + 4 + 9];
+  BLI_path_join(
+      osx_resourses, sizeof(osx_resourses), g_app.program_dirname, "..", "Resources", NULL);
   /* Remove the '/../' added above. */
   BLI_path_normalize(NULL, osx_resourses);
   path_base = osx_resourses;
@@ -734,6 +736,7 @@ const char *BKE_appdir_folder_id_create(const int folder_id, const char *subfold
             BLENDER_USER_CONFIG,
             BLENDER_USER_SCRIPTS,
             BLENDER_USER_AUTOSAVE)) {
+    BLI_assert_unreachable();
     return NULL;
   }
 
@@ -782,6 +785,7 @@ const char *BKE_appdir_folder_id_version(const int folder_id,
  * Access locations of Blender & Python.
  * \{ */
 
+#ifndef WITH_PYTHON_MODULE
 /**
  * Checks if name is a fully qualified filename to an executable.
  * If not it searches `$PATH` for the file. On Windows it also
@@ -796,7 +800,7 @@ const char *BKE_appdir_folder_id_version(const int folder_id,
  */
 static void where_am_i(char *fullname, const size_t maxlen, const char *name)
 {
-#ifdef WITH_BINRELOC
+#  ifdef WITH_BINRELOC
   /* Linux uses `binreloc` since `argv[0]` is not reliable, call `br_init(NULL)` first. */
   {
     const char *path = NULL;
@@ -807,9 +811,9 @@ static void where_am_i(char *fullname, const size_t maxlen, const char *name)
       return;
     }
   }
-#endif
+#  endif
 
-#ifdef _WIN32
+#  ifdef _WIN32
   {
     wchar_t *fullname_16 = MEM_mallocN(maxlen * sizeof(wchar_t), "ProgramPath");
     if (GetModuleFileNameW(0, fullname_16, maxlen)) {
@@ -825,7 +829,7 @@ static void where_am_i(char *fullname, const size_t maxlen, const char *name)
 
     MEM_freeN(fullname_16);
   }
-#endif
+#  endif
 
   /* Unix and non Linux. */
   if (name && name[0]) {
@@ -833,16 +837,16 @@ static void where_am_i(char *fullname, const size_t maxlen, const char *name)
     BLI_strncpy(fullname, name, maxlen);
     if (name[0] == '.') {
       BLI_path_abs_from_cwd(fullname, maxlen);
-#ifdef _WIN32
+#  ifdef _WIN32
       BLI_path_program_extensions_add_win32(fullname, maxlen);
-#endif
+#  endif
     }
     else if (BLI_path_slash_rfind(name)) {
       /* Full path. */
       BLI_strncpy(fullname, name, maxlen);
-#ifdef _WIN32
+#  ifdef _WIN32
       BLI_path_program_extensions_add_win32(fullname, maxlen);
-#endif
+#  endif
     }
     else {
       BLI_path_program_search(fullname, maxlen, name);
@@ -850,23 +854,43 @@ static void where_am_i(char *fullname, const size_t maxlen, const char *name)
     /* Remove "/./" and "/../" so string comparisons can be used on the path. */
     BLI_path_normalize(NULL, fullname);
 
-#if defined(DEBUG)
+#  if defined(DEBUG)
     if (!STREQ(name, fullname)) {
       CLOG_INFO(&LOG, 2, "guessing '%s' == '%s'", name, fullname);
     }
-#endif
+#  endif
   }
 }
+#endif /* WITH_PYTHON_MODULE */
 
 void BKE_appdir_program_path_init(const char *argv0)
 {
+#ifdef WITH_PYTHON_MODULE
+  /* NOTE(@campbellbarton): Always use `argv[0]` as is, when building as a Python module.
+   * Otherwise other methods of detecting the binary that override this argument
+   * which must point to the Python module for data-files to be detected. */
+  STRNCPY(g_app.program_filepath, argv0);
+  BLI_path_abs_from_cwd(g_app.program_filepath, sizeof(g_app.program_filepath));
+  BLI_path_normalize(NULL, g_app.program_filepath);
+
+  if (g_app.program_dirname[0] == '\0') {
+    /* First time initializing, the file binary path isn't valid from a Python module.
+     * Calling again must set the `filepath` and leave the directory as-is. */
+    BLI_split_dir_part(
+        g_app.program_filepath, g_app.program_dirname, sizeof(g_app.program_dirname));
+    g_app.program_filepath[0] = '\0';
+  }
+#else
   where_am_i(g_app.program_filepath, sizeof(g_app.program_filepath), argv0);
   BLI_split_dir_part(g_app.program_filepath, g_app.program_dirname, sizeof(g_app.program_dirname));
+#endif
 }
 
 const char *BKE_appdir_program_path(void)
 {
+#ifndef WITH_PYTHON_MODULE /* Default's to empty when building as a Python module. */
   BLI_assert(g_app.program_filepath[0]);
+#endif
   return g_app.program_filepath;
 }
 
diff --git a/source/blender/blenkernel/intern/armature.c b/source/blender/blenkernel/intern/armature.c
index f29074c827c..9b00d427320 100644
--- a/source/blender/blenkernel/intern/armature.c
+++ b/source/blender/blenkernel/intern/armature.c
@@ -97,7 +97,7 @@ static void armature_copy_data(Main *UNUSED(bmain), ID *id_dst, const ID *id_src
   Bone *bone_src, *bone_dst;
   Bone *bone_dst_act = NULL;
 
-  /* We never handle usercount here for own data. */
+  /* We never handle user-count here for own data. */
   const int flag_subdata = flag | LIB_ID_CREATE_NO_USER_REFCOUNT;
 
   armature_dst->bonehash = NULL;
@@ -261,12 +261,12 @@ static void armature_blend_read_data(BlendDataReader *reader, ID *id)
   BKE_armature_bone_hash_make(arm);
 }
 
-static void lib_link_bones(BlendLibReader *reader, Bone *bone)
+static void lib_link_bones(BlendLibReader *reader, Library *lib, Bone *bone)
 {
-  IDP_BlendReadLib(reader, bone->prop);
+  IDP_BlendReadLib(reader, lib, bone->prop);
 
   LISTBASE_FOREACH (Bone *, curbone, &bone->childbase) {
-    lib_link_bones(reader, curbone);
+    lib_link_bones(reader, lib, curbone);
   }
 }
 
@@ -274,7 +274,7 @@ static void armature_blend_read_lib(BlendLibReader *reader, ID *id)
 {
   bArmature *arm = (bArmature *)id;
   LISTBASE_FOREACH (Bone *, curbone, &arm->bonebase) {
-    lib_link_bones(reader, curbone);
+    lib_link_bones(reader, id->lib, curbone);
   }
 }
 
@@ -313,7 +313,7 @@ IDTypeInfo IDType_ID_AR = {
     .foreach_id = armature_foreach_id,
     .foreach_cache = NULL,
     .foreach_path = NULL,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = armature_blend_write,
     .blend_read_data = armature_blend_read_data,
diff --git a/source/blender/blenkernel/intern/armature_deform.c b/source/blender/blenkernel/intern/armature_deform.c
index 0769049e9a9..84bb1af011a 100644
--- a/source/blender/blenkernel/intern/armature_deform.c
+++ b/source/blender/blenkernel/intern/armature_deform.c
@@ -35,6 +35,7 @@
 #include "BKE_deform.h"
 #include "BKE_editmesh.h"
 #include "BKE_lattice.h"
+#include "BKE_mesh.h"
 
 #include "DEG_depsgraph_build.h"
 
@@ -159,9 +160,9 @@ float distfactor_to_bone(
 }
 
 static float dist_bone_deform(
-    bPoseChannel *pchan, float vec[3], DualQuat *dq, float mat[3][3], const float co[3])
+    const bPoseChannel *pchan, float vec[3], DualQuat *dq, float mat[3][3], const float co[3])
 {
-  Bone *bone = pchan->bone;
+  const Bone *bone = pchan->bone;
   float fac, contrib = 0.0;
 
   if (bone == NULL) {
@@ -188,7 +189,7 @@ static float dist_bone_deform(
   return contrib;
 }
 
-static void pchan_bone_deform(bPoseChannel *pchan,
+static void pchan_bone_deform(const bPoseChannel *pchan,
                               float weight,
                               float vec[3],
                               DualQuat *dq,
@@ -196,7 +197,7 @@ static void pchan_bone_deform(bPoseChannel *pchan,
                               const float co[3],
                               float *contrib)
 {
-  Bone *bone = pchan->bone;
+  const Bone *bone = pchan->bone;
 
   if (!weight) {
     return;
@@ -223,7 +224,6 @@ static void pchan_bone_deform(bPoseChannel *pchan,
 
 typedef struct ArmatureUserdata {
   const Object *ob_arm;
-  const Object *ob_target;
   const Mesh *me_target;
   float (*vert_coords)[3];
   float (*vert_deform_mats)[3][3];
@@ -264,7 +264,7 @@ static void armature_vert_task_with_dvert(const ArmatureUserdata *data,
   const int armature_def_nr = data->armature_def_nr;
 
   DualQuat sumdq, *dq = NULL;
-  bPoseChannel *pchan;
+  const bPoseChannel *pchan;
   float *co, dco[3];
   float sumvec[3], summat[3][3];
   float *vec = NULL, (*smat)[3] = NULL;
@@ -319,7 +319,7 @@ static void armature_vert_task_with_dvert(const ArmatureUserdata *data,
       const uint index = dw->def_nr;
       if (index < data->defbase_len && (pchan = data->pchan_from_defbase[index])) {
         float weight = dw->weight;
-        Bone *bone = pchan->bone;
+        const Bone *bone = pchan->bone;
 
         deformed = 1;
 
@@ -407,8 +407,8 @@ static void armature_vert_task(void *__restrict userdata,
   if (data->use_dverts || data->armature_def_nr != -1) {
     if (data->me_target) {
       BLI_assert(i < data->me_target->totvert);
-      if (data->me_target->dvert != NULL) {
-        dvert = data->me_target->dvert + i;
+      if (data->dverts != NULL) {
+        dvert = data->dverts + i;
       }
       else {
         dvert = NULL;
@@ -434,7 +434,7 @@ static void armature_vert_task_editmesh(void *__restrict userdata,
 {
   const ArmatureUserdata *data = userdata;
   BMVert *v = (BMVert *)iter;
-  MDeformVert *dvert = BM_ELEM_CD_GET_VOID_P(v, data->bmesh.cd_dvert_offset);
+  const MDeformVert *dvert = BM_ELEM_CD_GET_VOID_P(v, data->bmesh.cd_dvert_offset);
   armature_vert_task_with_dvert(data, BM_elem_index_get(v), dvert);
 }
 
@@ -459,15 +459,14 @@ static void armature_deform_coords_impl(const Object *ob_arm,
                                         BMEditMesh *em_target,
                                         bGPDstroke *gps_target)
 {
-  bArmature *arm = ob_arm->data;
+  const bArmature *arm = ob_arm->data;
   bPoseChannel **pchan_from_defbase = NULL;
   const MDeformVert *dverts = NULL;
-  bDeformGroup *dg;
   const bool use_envelope = (deformflag & ARM_DEF_ENVELOPE) != 0;
   const bool use_quaternion = (deformflag & ARM_DEF_QUATERNION) != 0;
   const bool invert_vgroup = (deformflag & ARM_DEF_INVERT_VGROUP) != 0;
-  int defbase_len = 0;   /* safety for vertexgroup index overflow */
-  int i, dverts_len = 0; /* safety for vertexgroup overflow */
+  int defbase_len = 0; /* safety for vertexgroup index overflow */
+  int dverts_len = 0;  /* safety for vertexgroup overflow */
   bool use_dverts = false;
   int armature_def_nr = -1;
   int cd_dvert_offset = -1;
@@ -485,34 +484,38 @@ static void armature_deform_coords_impl(const Object *ob_arm,
   }
 
   if (BKE_object_supports_vertex_groups(ob_target)) {
-    /* get the def_nr for the overall armature vertex group if present */
-    armature_def_nr = BKE_object_defgroup_name_index(ob_target, defgrp_name);
-
-    defbase_len = BKE_object_defgroup_count(ob_target);
-
+    const ID *target_data_id = NULL;
     if (ob_target->type == OB_MESH) {
+      target_data_id = me_target == NULL ? (const ID *)ob_target->data : &me_target->id;
       if (em_target == NULL) {
-        Mesh *me = ob_target->data;
-        dverts = me->dvert;
+        const Mesh *me = (const Mesh *)target_data_id;
+        dverts = BKE_mesh_deform_verts(me);
         if (dverts) {
           dverts_len = me->totvert;
         }
       }
     }
     else if (ob_target->type == OB_LATTICE) {
-      Lattice *lt = ob_target->data;
+      const Lattice *lt = ob_target->data;
+      target_data_id = (const ID *)ob_target->data;
       dverts = lt->dvert;
       if (dverts) {
         dverts_len = lt->pntsu * lt->pntsv * lt->pntsw;
       }
     }
     else if (ob_target->type == OB_GPENCIL) {
+      target_data_id = (const ID *)ob_target->data;
       dverts = gps_target->dvert;
       if (dverts) {
         dverts_len = gps_target->totpoints;
       }
     }
 
+    /* Collect the vertex group names from the evaluated data. */
+    armature_def_nr = BKE_id_defgroup_name_index(target_data_id, defgrp_name);
+    const ListBase *defbase = BKE_id_defgroup_list_get(target_data_id);
+    defbase_len = BLI_listbase_count(defbase);
+
     /* get a vertex-deform-index to posechannel array */
     if (deformflag & ARM_DEF_VGROUP) {
       /* if we have a Mesh, only use dverts if it has them */
@@ -521,7 +524,7 @@ static void armature_deform_coords_impl(const Object *ob_arm,
         use_dverts = (cd_dvert_offset != -1);
       }
       else if (me_target) {
-        use_dverts = (me_target->dvert != NULL);
+        use_dverts = (BKE_mesh_deform_verts(me_target) != NULL);
       }
       else if (dverts) {
         use_dverts = true;
@@ -533,8 +536,8 @@ static void armature_deform_coords_impl(const Object *ob_arm,
          *
          * - Check whether keeping this consistent across frames gives speedup.
          */
-        const ListBase *defbase = BKE_object_defgroup_list(ob_target);
-        for (i = 0, dg = defbase->first; dg; i++, dg = dg->next) {
+        int i;
+        LISTBASE_FOREACH_INDEX (bDeformGroup *, dg, defbase, i) {
           pchan_from_defbase[i] = BKE_pose_channel_find_name(ob_arm->pose, dg->name);
           /* exclude non-deforming bones */
           if (pchan_from_defbase[i]) {
@@ -549,7 +552,6 @@ static void armature_deform_coords_impl(const Object *ob_arm,
 
   ArmatureUserdata data = {
       .ob_arm = ob_arm,
-      .ob_target = ob_target,
       .me_target = me_target,
       .vert_coords = vert_coords,
       .vert_deform_mats = vert_deform_mats,
diff --git a/source/blender/blenkernel/intern/armature_update.c b/source/blender/blenkernel/intern/armature_update.c
index 2db4c086e04..6d7aed239e7 100644
--- a/source/blender/blenkernel/intern/armature_update.c
+++ b/source/blender/blenkernel/intern/armature_update.c
@@ -288,7 +288,7 @@ static int position_tail_on_spline(bSplineIKConstraint *ik_data,
   int max_seg_idx = BKE_anim_path_get_array_size(cache) - 1;
 
   /* Make an initial guess of where our intersection point will be.
-   * If the curve was a straight line, then the faction passed in r_new_curve_pos
+   * If the curve was a straight line, then the fraction passed in r_new_curve_pos
    * would be the correct location.
    * So make it our first initial guess.
    */
diff --git a/source/blender/blenkernel/intern/asset_catalog.cc b/source/blender/blenkernel/intern/asset_catalog.cc
index fccff602d2e..f7b14cc3479 100644
--- a/source/blender/blenkernel/intern/asset_catalog.cc
+++ b/source/blender/blenkernel/intern/asset_catalog.cc
@@ -516,7 +516,7 @@ CatalogFilePath AssetCatalogService::find_suitable_cdf_path_for_writing(
                   sizeof(asset_lib_cdf_path),
                   suitable_root_path,
                   DEFAULT_CATALOG_FILENAME.c_str(),
-                  NULL);
+                  nullptr);
     return asset_lib_cdf_path;
   }
 
diff --git a/source/blender/blenkernel/intern/attribute.cc b/source/blender/blenkernel/intern/attribute.cc
index 030e4941874..bd3e452b7f2 100644
--- a/source/blender/blenkernel/intern/attribute.cc
+++ b/source/blender/blenkernel/intern/attribute.cc
@@ -8,6 +8,7 @@
  */
 
 #include 
+#include 
 
 #include "MEM_guardedalloc.h"
 
@@ -19,12 +20,15 @@
 #include "DNA_pointcloud_types.h"
 
 #include "BLI_index_range.hh"
+#include "BLI_string.h"
 #include "BLI_string_utf8.h"
 #include "BLI_string_utils.h"
 
+#include "BLT_translation.h"
+
 #include "BKE_attribute.h"
 #include "BKE_attribute.hh"
-#include "BKE_curves.h"
+#include "BKE_curves.hh"
 #include "BKE_customdata.h"
 #include "BKE_editmesh.h"
 #include "BKE_pointcloud.h"
@@ -89,6 +93,36 @@ static void get_domains(const ID *id, DomainInfo info[ATTR_DOMAIN_NUM])
   }
 }
 
+namespace blender::bke {
+
+static std::optional get_attribute_accessor_for_write(
+    ID &id)
+{
+  switch (GS(id.name)) {
+    case ID_ME: {
+      Mesh &mesh = reinterpret_cast(id);
+      /* The attribute API isn't implemented for BMesh, so edit mode meshes are not supported. */
+      BLI_assert(mesh.edit_mesh == nullptr);
+      return mesh.attributes_for_write();
+    }
+    case ID_PT: {
+      PointCloud &pointcloud = reinterpret_cast(id);
+      return pointcloud.attributes_for_write();
+    }
+    case ID_CV: {
+      Curves &curves_id = reinterpret_cast(id);
+      CurvesGeometry &curves = CurvesGeometry::wrap(curves_id.geometry);
+      return curves.attributes_for_write();
+    }
+    default: {
+      BLI_assert_unreachable();
+      return {};
+    }
+  }
+}
+
+}  // namespace blender::bke
+
 bool BKE_id_attributes_supported(const ID *id)
 {
   DomainInfo info[ATTR_DOMAIN_NUM];
@@ -115,6 +149,13 @@ bool BKE_id_attribute_rename(ID *id,
     BLI_assert_msg(0, "Required attribute name is not editable");
     return false;
   }
+  if (STREQ(new_name, "")) {
+    BKE_report(reports, RPT_ERROR, "Attribute name can not be empty");
+    return false;
+  }
+  if (STREQ(old_name, new_name)) {
+    return false;
+  }
 
   CustomDataLayer *layer = BKE_id_attribute_search(
       id, old_name, CD_MASK_PROP_ALL, ATTR_DOMAIN_MASK_ALL);
@@ -146,9 +187,9 @@ static bool unique_name_cb(void *arg, const char *name)
       continue;
     }
 
-    CustomData *cdata = info[domain].customdata;
+    const CustomData *cdata = info[domain].customdata;
     for (int i = 0; i < cdata->totlayer; i++) {
-      CustomDataLayer *layer = cdata->layers + i;
+      const CustomDataLayer *layer = cdata->layers + i;
 
       if (STREQ(layer->name, name)) {
         return true;
@@ -163,7 +204,14 @@ bool BKE_id_attribute_calc_unique_name(ID *id, const char *name, char *outname)
 {
   AttrUniqueData data{id};
 
-  BLI_strncpy_utf8(outname, name, MAX_CUSTOMDATA_LAYER_NAME);
+  /* Set default name if none specified.
+   * NOTE: We only call IFACE_() if needed to avoid locale lookup overhead. */
+  if (!name || name[0] == '\0') {
+    BLI_strncpy(outname, IFACE_("Attribute"), MAX_CUSTOMDATA_LAYER_NAME);
+  }
+  else {
+    BLI_strncpy_utf8(outname, name, MAX_CUSTOMDATA_LAYER_NAME);
+  }
 
   return BLI_uniquename_cb(
       unique_name_cb, &data, nullptr, '.', outname, MAX_CUSTOMDATA_LAYER_NAME);
@@ -172,6 +220,7 @@ bool BKE_id_attribute_calc_unique_name(ID *id, const char *name, char *outname)
 CustomDataLayer *BKE_id_attribute_new(
     ID *id, const char *name, const int type, const eAttrDomain domain, ReportList *reports)
 {
+  using namespace blender::bke;
   DomainInfo info[ATTR_DOMAIN_NUM];
   get_domains(id, info);
 
@@ -184,64 +233,65 @@ CustomDataLayer *BKE_id_attribute_new(
   char uniquename[MAX_CUSTOMDATA_LAYER_NAME];
   BKE_id_attribute_calc_unique_name(id, name, uniquename);
 
-  switch (GS(id->name)) {
-    case ID_ME: {
-      Mesh *me = (Mesh *)id;
-      BMEditMesh *em = me->edit_mesh;
-      if (em != nullptr) {
-        BM_data_layer_add_named(em->bm, customdata, type, uniquename);
-      }
-      else {
-        CustomData_add_layer_named(
-            customdata, type, CD_DEFAULT, nullptr, info[domain].length, uniquename);
-      }
-      break;
-    }
-    default: {
-      CustomData_add_layer_named(
-          customdata, type, CD_DEFAULT, nullptr, info[domain].length, uniquename);
-      break;
+  if (GS(id->name) == ID_ME) {
+    Mesh *mesh = reinterpret_cast(id);
+    if (BMEditMesh *em = mesh->edit_mesh) {
+      BM_data_layer_add_named(em->bm, customdata, type, uniquename);
+      const int index = CustomData_get_named_layer_index(customdata, type, uniquename);
+      return (index == -1) ? nullptr : &(customdata->layers[index]);
     }
   }
 
+  std::optional attributes = get_attribute_accessor_for_write(*id);
+  if (!attributes) {
+    return nullptr;
+  }
+
+  attributes->add(uniquename, domain, eCustomDataType(type), AttributeInitDefaultValue());
+
   const int index = CustomData_get_named_layer_index(customdata, type, uniquename);
   return (index == -1) ? nullptr : &(customdata->layers[index]);
 }
 
 CustomDataLayer *BKE_id_attribute_duplicate(ID *id, const char *name, ReportList *reports)
 {
-  const CustomDataLayer *src_layer = BKE_id_attribute_search(
-      id, name, CD_MASK_PROP_ALL, ATTR_DOMAIN_MASK_ALL);
-  if (src_layer == nullptr) {
-    BKE_report(reports, RPT_ERROR, "Attribute is not part of this geometry");
-    return nullptr;
-  }
-
-  const eCustomDataType type = (eCustomDataType)src_layer->type;
-  const eAttrDomain domain = BKE_id_attribute_domain(id, src_layer);
+  using namespace blender::bke;
+  char uniquename[MAX_CUSTOMDATA_LAYER_NAME];
+  BKE_id_attribute_calc_unique_name(id, name, uniquename);
 
-  /* Make a copy of name in case CustomData API reallocates the layers. */
-  const std::string name_copy = name;
+  if (GS(id->name) == ID_ME) {
+    Mesh *mesh = reinterpret_cast(id);
+    if (BMEditMesh *em = mesh->edit_mesh) {
+      BLI_assert_unreachable();
+      UNUSED_VARS(em);
+      return nullptr;
+    }
+  }
 
-  DomainInfo info[ATTR_DOMAIN_NUM];
-  get_domains(id, info);
-  CustomData *customdata = info[domain].customdata;
+  std::optional attributes = get_attribute_accessor_for_write(*id);
+  if (!attributes) {
+    return nullptr;
+  }
 
-  CustomDataLayer *new_layer = BKE_id_attribute_new(id, name_copy.c_str(), type, domain, reports);
-  if (new_layer == nullptr) {
+  GAttributeReader src = attributes->lookup(name);
+  if (!src) {
+    BKE_report(reports, RPT_ERROR, "Attribute is not part of this geometry");
     return nullptr;
   }
 
-  const int from_index = CustomData_get_named_layer_index(customdata, type, name_copy.c_str());
-  const int to_index = CustomData_get_named_layer_index(customdata, type, new_layer->name);
-  CustomData_copy_data_layer(
-      customdata, customdata, from_index, to_index, 0, 0, info[domain].length);
+  const eCustomDataType type = cpp_type_to_custom_data_type(src.varray.type());
+  attributes->add(uniquename, src.domain, type, AttributeInitVArray(src.varray));
 
-  return new_layer;
+  return BKE_id_attribute_search(id, uniquename, CD_MASK_PROP_ALL, ATTR_DOMAIN_MASK_ALL);
 }
 
 bool BKE_id_attribute_remove(ID *id, const char *name, ReportList *reports)
 {
+  using namespace blender::bke;
+  if (!name || name[0] == '\0') {
+    BKE_report(reports, RPT_ERROR, "The attribute name must not be empty");
+    return false;
+  }
   if (BKE_id_attribute_required(id, name)) {
     BKE_report(reports, RPT_ERROR, "Attribute is required and can't be removed");
     return false;
@@ -250,31 +300,26 @@ bool BKE_id_attribute_remove(ID *id, const char *name, ReportList *reports)
   DomainInfo info[ATTR_DOMAIN_NUM];
   get_domains(id, info);
 
-  switch (GS(id->name)) {
-    case ID_ME: {
-      Mesh *mesh = reinterpret_cast(id);
-      if (BMEditMesh *em = mesh->edit_mesh) {
-        for (const int domain : IndexRange(ATTR_DOMAIN_NUM)) {
-          if (CustomData *data = info[domain].customdata) {
-            if (BM_data_layer_free_named(em->bm, data, name)) {
-              return true;
-            }
-          }
-        }
-        return false;
-      }
-      ATTR_FALLTHROUGH;
-    }
-    default:
+  if (GS(id->name) == ID_ME) {
+    Mesh *mesh = reinterpret_cast(id);
+    if (BMEditMesh *em = mesh->edit_mesh) {
       for (const int domain : IndexRange(ATTR_DOMAIN_NUM)) {
         if (CustomData *data = info[domain].customdata) {
-          if (CustomData_free_layer_named(data, name, info[domain].length)) {
+          if (BM_data_layer_free_named(em->bm, data, name)) {
             return true;
           }
         }
       }
       return false;
+    }
+  }
+
+  std::optional attributes = get_attribute_accessor_for_write(*id);
+  if (!attributes) {
+    return false;
   }
+
+  return attributes->remove(name);
 }
 
 CustomDataLayer *BKE_id_attribute_find(const ID *id,
@@ -338,9 +383,12 @@ int BKE_id_attributes_length(const ID *id, eAttrDomainMask domain_mask, eCustomD
   int length = 0;
 
   for (const int domain : IndexRange(ATTR_DOMAIN_NUM)) {
-    CustomData *customdata = info[domain].customdata;
+    const CustomData *customdata = info[domain].customdata;
+    if (customdata == nullptr) {
+      continue;
+    }
 
-    if (customdata && ((1 << (int)domain) & domain_mask)) {
+    if ((1 << (int)domain) & domain_mask) {
       length += CustomData_number_of_layers_typemask(customdata, mask);
     }
   }
@@ -354,9 +402,11 @@ eAttrDomain BKE_id_attribute_domain(const ID *id, const CustomDataLayer *layer)
   get_domains(id, info);
 
   for (const int domain : IndexRange(ATTR_DOMAIN_NUM)) {
-    CustomData *customdata = info[domain].customdata;
-    if (customdata &&
-        ARRAY_HAS_ITEM((CustomDataLayer *)layer, customdata->layers, customdata->totlayer)) {
+    const CustomData *customdata = info[domain].customdata;
+    if (customdata == nullptr) {
+      continue;
+    }
+    if (ARRAY_HAS_ITEM((CustomDataLayer *)layer, customdata->layers, customdata->totlayer)) {
       return static_cast(domain);
     }
   }
@@ -376,6 +426,7 @@ int BKE_id_attribute_data_length(ID *id, CustomDataLayer *layer)
       if (mesh->edit_mesh != nullptr) {
         return 0;
       }
+      break;
     }
     default:
       break;
@@ -385,9 +436,11 @@ int BKE_id_attribute_data_length(ID *id, CustomDataLayer *layer)
   get_domains(id, info);
 
   for (const int domain : IndexRange(ATTR_DOMAIN_NUM)) {
-    CustomData *customdata = info[domain].customdata;
-    if (customdata &&
-        ARRAY_HAS_ITEM((CustomDataLayer *)layer, customdata->layers, customdata->totlayer)) {
+    const CustomData *customdata = info[domain].customdata;
+    if (customdata == nullptr) {
+      continue;
+    }
+    if (ARRAY_HAS_ITEM((CustomDataLayer *)layer, customdata->layers, customdata->totlayer)) {
       return info[domain].length;
     }
   }
@@ -399,12 +452,10 @@ int BKE_id_attribute_data_length(ID *id, CustomDataLayer *layer)
 bool BKE_id_attribute_required(const ID *id, const char *name)
 {
   switch (GS(id->name)) {
-    case ID_PT: {
-      return BKE_pointcloud_customdata_required((const PointCloud *)id, name);
-    }
-    case ID_CV: {
-      return BKE_curves_customdata_required((const Curves *)id, name);
-    }
+    case ID_PT:
+      return BKE_pointcloud_attribute_required((const PointCloud *)id, name);
+    case ID_CV:
+      return BKE_curves_attribute_required((const Curves *)id, name);
     default:
       return false;
   }
@@ -424,15 +475,19 @@ CustomDataLayer *BKE_id_attributes_active_get(ID *id)
 
   for (const int domain : IndexRange(ATTR_DOMAIN_NUM)) {
     CustomData *customdata = info[domain].customdata;
-    if (customdata) {
-      for (int i = 0; i < customdata->totlayer; i++) {
-        CustomDataLayer *layer = &customdata->layers[i];
-        if (CD_MASK_PROP_ALL & CD_TYPE_AS_MASK(layer->type)) {
-          if (index == active_index) {
+    if (customdata == nullptr) {
+      continue;
+    }
+    for (int i = 0; i < customdata->totlayer; i++) {
+      CustomDataLayer *layer = &customdata->layers[i];
+      if (CD_MASK_PROP_ALL & CD_TYPE_AS_MASK(layer->type)) {
+        if (index == active_index) {
+          if (BKE_attribute_allow_procedural_access(layer->name)) {
             return layer;
           }
-          index++;
+          return nullptr;
         }
+        index++;
       }
     }
   }
@@ -448,17 +503,18 @@ void BKE_id_attributes_active_set(ID *id, CustomDataLayer *active_layer)
   int index = 0;
 
   for (const int domain : IndexRange(ATTR_DOMAIN_NUM)) {
-    CustomData *customdata = info[domain].customdata;
-    if (customdata) {
-      for (int i = 0; i < customdata->totlayer; i++) {
-        CustomDataLayer *layer = &customdata->layers[i];
-        if (layer == active_layer) {
-          *BKE_id_attributes_active_index_p(id) = index;
-          return;
-        }
-        if (CD_MASK_PROP_ALL & CD_TYPE_AS_MASK(layer->type)) {
-          index++;
-        }
+    const CustomData *customdata = info[domain].customdata;
+    if (customdata == nullptr) {
+      continue;
+    }
+    for (int i = 0; i < customdata->totlayer; i++) {
+      const CustomDataLayer *layer = &customdata->layers[i];
+      if (layer == active_layer) {
+        *BKE_id_attributes_active_index_p(id) = index;
+        return;
+      }
+      if (CD_MASK_PROP_ALL & CD_TYPE_AS_MASK(layer->type)) {
+        index++;
       }
     }
   }
@@ -490,7 +546,10 @@ CustomData *BKE_id_attributes_iterator_next_domain(ID *id, CustomDataLayer *laye
 
   for (const int domain : IndexRange(ATTR_DOMAIN_NUM)) {
     CustomData *customdata = info[domain].customdata;
-    if (customdata && customdata->layers && customdata->totlayer) {
+    if (customdata == nullptr) {
+      continue;
+    }
+    if (customdata->layers && customdata->totlayer) {
       if (customdata->layers == layers) {
         use_next = true;
       }
diff --git a/source/blender/blenkernel/intern/attribute_access.cc b/source/blender/blenkernel/intern/attribute_access.cc
index ac1ee19927c..df7787986db 100644
--- a/source/blender/blenkernel/intern/attribute_access.cc
+++ b/source/blender/blenkernel/intern/attribute_access.cc
@@ -5,7 +5,6 @@
 #include "BKE_attribute_math.hh"
 #include "BKE_customdata.h"
 #include "BKE_deform.h"
-#include "BKE_geometry_fields.hh"
 #include "BKE_geometry_set.hh"
 #include "BKE_mesh.h"
 #include "BKE_pointcloud.h"
@@ -15,10 +14,13 @@
 #include "DNA_meshdata_types.h"
 #include "DNA_pointcloud_types.h"
 
+#include "BLI_array_utils.hh"
 #include "BLI_color.hh"
 #include "BLI_math_vec_types.hh"
 #include "BLI_span.hh"
 
+#include "FN_field.hh"
+
 #include "BLT_translation.h"
 
 #include "CLG_log.h"
@@ -56,7 +58,8 @@ const char *no_procedural_access_message =
 
 bool allow_procedural_attribute_access(StringRef attribute_name)
 {
-  return !attribute_name.startswith(".selection");
+  return !attribute_name.startswith(".sculpt") && !attribute_name.startswith(".selection") &&
+         !attribute_name.startswith(".hide");
 }
 
 static int attribute_data_type_complexity(const eCustomDataType data_type)
@@ -161,12 +164,19 @@ static bool add_builtin_type_custom_data_layer_from_init(CustomData &custom_data
                                                          const AttributeInit &initializer)
 {
   switch (initializer.type) {
-    case AttributeInit::Type::Default: {
-      void *data = CustomData_add_layer(&custom_data, data_type, CD_DEFAULT, nullptr, domain_num);
+    case AttributeInit::Type::Construct: {
+      void *data = CustomData_add_layer(
+          &custom_data, data_type, CD_CONSTRUCT, nullptr, domain_num);
+      return data != nullptr;
+    }
+    case AttributeInit::Type::DefaultValue: {
+      void *data = CustomData_add_layer(
+          &custom_data, data_type, CD_SET_DEFAULT, nullptr, domain_num);
       return data != nullptr;
     }
     case AttributeInit::Type::VArray: {
-      void *data = CustomData_add_layer(&custom_data, data_type, CD_DEFAULT, nullptr, domain_num);
+      void *data = CustomData_add_layer(
+          &custom_data, data_type, CD_CONSTRUCT, nullptr, domain_num);
       if (data == nullptr) {
         return false;
       }
@@ -175,7 +185,7 @@ static bool add_builtin_type_custom_data_layer_from_init(CustomData &custom_data
       return true;
     }
     case AttributeInit::Type::MoveArray: {
-      void *source_data = static_cast(initializer).data;
+      void *source_data = static_cast(initializer).data;
       void *data = CustomData_add_layer(
           &custom_data, data_type, CD_ASSIGN, source_data, domain_num);
       if (data == nullptr) {
@@ -214,36 +224,38 @@ static bool add_custom_data_layer_from_attribute_init(const AttributeIDRef &attr
                                                       const int domain_num,
                                                       const AttributeInit &initializer)
 {
+  const int old_layer_num = custom_data.totlayer;
   switch (initializer.type) {
-    case AttributeInit::Type::Default: {
-      void *data = add_generic_custom_data_layer(
-          custom_data, data_type, CD_DEFAULT, nullptr, domain_num, attribute_id);
-      return data != nullptr;
+    case AttributeInit::Type::Construct: {
+      add_generic_custom_data_layer(
+          custom_data, data_type, CD_CONSTRUCT, nullptr, domain_num, attribute_id);
+      break;
+    }
+    case AttributeInit::Type::DefaultValue: {
+      add_generic_custom_data_layer(
+          custom_data, data_type, CD_SET_DEFAULT, nullptr, domain_num, attribute_id);
+      break;
     }
     case AttributeInit::Type::VArray: {
       void *data = add_generic_custom_data_layer(
-          custom_data, data_type, CD_DEFAULT, nullptr, domain_num, attribute_id);
-      if (data == nullptr) {
-        return false;
+          custom_data, data_type, CD_CONSTRUCT, nullptr, domain_num, attribute_id);
+      if (data != nullptr) {
+        const GVArray &varray = static_cast(initializer).varray;
+        varray.materialize_to_uninitialized(varray.index_range(), data);
       }
-      const GVArray &varray = static_cast(initializer).varray;
-      varray.materialize_to_uninitialized(varray.index_range(), data);
-      return true;
+      break;
     }
     case AttributeInit::Type::MoveArray: {
-      void *source_data = static_cast(initializer).data;
+      void *source_data = static_cast(initializer).data;
       void *data = add_generic_custom_data_layer(
           custom_data, data_type, CD_ASSIGN, source_data, domain_num, attribute_id);
-      if (data == nullptr) {
+      if (source_data != nullptr && data == nullptr) {
         MEM_freeN(source_data);
-        return false;
       }
-      return true;
+      break;
     }
   }
-
-  BLI_assert_unreachable();
-  return false;
+  return old_layer_num < custom_data.totlayer;
 }
 
 static bool custom_data_layer_matches_attribute_id(const CustomDataLayer &layer,
@@ -258,6 +270,14 @@ static bool custom_data_layer_matches_attribute_id(const CustomDataLayer &layer,
   return layer.name == attribute_id.name();
 }
 
+bool BuiltinCustomDataLayerProvider::layer_exists(const CustomData &custom_data) const
+{
+  if (stored_as_named_attribute_) {
+    return CustomData_get_named_layer_index(&custom_data, stored_type_, name_.c_str()) != -1;
+  }
+  return CustomData_has_layer(&custom_data, stored_type_);
+}
+
 GVArray BuiltinCustomDataLayerProvider::try_get_for_read(const void *owner) const
 {
   const CustomData *custom_data = custom_data_access_.get_const_custom_data(owner);
@@ -265,7 +285,16 @@ GVArray BuiltinCustomDataLayerProvider::try_get_for_read(const void *owner) cons
     return {};
   }
 
-  const void *data;
+  /* When the number of elements is zero, layers might have null data but still exist. */
+  const int element_num = custom_data_access_.get_element_num(owner);
+  if (element_num == 0) {
+    if (this->layer_exists(*custom_data)) {
+      return as_read_attribute_(nullptr, 0);
+    }
+    return {};
+  }
+
+  const void *data = nullptr;
   if (stored_as_named_attribute_) {
     data = CustomData_get_layer_named(custom_data, stored_type_, name_.c_str());
   }
@@ -275,8 +304,6 @@ GVArray BuiltinCustomDataLayerProvider::try_get_for_read(const void *owner) cons
   if (data == nullptr) {
     return {};
   }
-
-  const int element_num = custom_data_access_.get_element_num(owner);
   return as_read_attribute_(data, element_num);
 }
 
@@ -289,40 +316,32 @@ GAttributeWriter BuiltinCustomDataLayerProvider::try_get_for_write(void *owner)
   if (custom_data == nullptr) {
     return {};
   }
-  const int element_num = custom_data_access_.get_element_num(owner);
 
-  void *data;
-  if (stored_as_named_attribute_) {
-    data = CustomData_get_layer_named(custom_data, stored_type_, name_.c_str());
-  }
-  else {
-    data = CustomData_get_layer(custom_data, stored_type_);
+  std::function tag_modified_fn;
+  if (update_on_change_ != nullptr) {
+    tag_modified_fn = [owner, update = update_on_change_]() { update(owner); };
   }
-  if (data == nullptr) {
+
+  /* When the number of elements is zero, layers might have null data but still exist. */
+  const int element_num = custom_data_access_.get_element_num(owner);
+  if (element_num == 0) {
+    if (this->layer_exists(*custom_data)) {
+      return {as_write_attribute_(nullptr, 0), domain_, std::move(tag_modified_fn)};
+    }
     return {};
   }
 
-  void *new_data;
+  void *data = nullptr;
   if (stored_as_named_attribute_) {
-    new_data = CustomData_duplicate_referenced_layer_named(
+    data = CustomData_duplicate_referenced_layer_named(
         custom_data, stored_type_, name_.c_str(), element_num);
   }
   else {
-    new_data = CustomData_duplicate_referenced_layer(custom_data, stored_type_, element_num);
+    data = CustomData_duplicate_referenced_layer(custom_data, stored_type_, element_num);
   }
-
-  if (data != new_data) {
-    if (custom_data_access_.update_custom_data_pointers) {
-      custom_data_access_.update_custom_data_pointers(owner);
-    }
-    data = new_data;
-  }
-
-  std::function tag_modified_fn;
-  if (update_on_write_ != nullptr) {
-    tag_modified_fn = [owner, update = update_on_write_]() { update(owner); };
+  if (data == nullptr) {
+    return {};
   }
-
   return {as_write_attribute_(data, element_num), domain_, std::move(tag_modified_fn)};
 }
 
@@ -336,12 +355,16 @@ bool BuiltinCustomDataLayerProvider::try_delete(void *owner) const
     return {};
   }
 
+  auto update = [&]() {
+    if (update_on_change_ != nullptr) {
+      update_on_change_(owner);
+    }
+  };
+
   const int element_num = custom_data_access_.get_element_num(owner);
   if (stored_as_named_attribute_) {
     if (CustomData_free_layer_named(custom_data, name_.c_str(), element_num)) {
-      if (custom_data_access_.update_custom_data_pointers) {
-        custom_data_access_.update_custom_data_pointers(owner);
-      }
+      update();
       return true;
     }
     return false;
@@ -349,11 +372,10 @@ bool BuiltinCustomDataLayerProvider::try_delete(void *owner) const
 
   const int layer_index = CustomData_get_layer_index(custom_data, stored_type_);
   if (CustomData_free_layer(custom_data, stored_type_, element_num, layer_index)) {
-    if (custom_data_access_.update_custom_data_pointers) {
-      custom_data_access_.update_custom_data_pointers(owner);
-    }
+    update();
     return true;
   }
+
   return false;
 }
 
@@ -369,29 +391,21 @@ bool BuiltinCustomDataLayerProvider::try_create(void *owner,
   }
 
   const int element_num = custom_data_access_.get_element_num(owner);
-  bool success;
   if (stored_as_named_attribute_) {
     if (CustomData_get_layer_named(custom_data, data_type_, name_.c_str())) {
       /* Exists already. */
       return false;
     }
-    success = add_custom_data_layer_from_attribute_init(
+    return add_custom_data_layer_from_attribute_init(
         name_, *custom_data, stored_type_, element_num, initializer);
   }
-  else {
-    if (CustomData_get_layer(custom_data, stored_type_) != nullptr) {
-      /* Exists already. */
-      return false;
-    }
-    success = add_builtin_type_custom_data_layer_from_init(
-        *custom_data, stored_type_, element_num, initializer);
-  }
-  if (success) {
-    if (custom_data_access_.update_custom_data_pointers) {
-      custom_data_access_.update_custom_data_pointers(owner);
-    }
+
+  if (CustomData_get_layer(custom_data, stored_type_) != nullptr) {
+    /* Exists already. */
+    return false;
   }
-  return success;
+  return add_builtin_type_custom_data_layer_from_init(
+      *custom_data, stored_type_, element_num, initializer);
 }
 
 bool BuiltinCustomDataLayerProvider::exists(const void *owner) const
@@ -553,15 +567,9 @@ GAttributeWriter NamedLegacyCustomDataProvider::try_get_for_write(
     if (layer.type == stored_type_) {
       if (custom_data_layer_matches_attribute_id(layer, attribute_id)) {
         const int element_num = custom_data_access_.get_element_num(owner);
-        void *data_old = layer.data;
-        void *data_new = CustomData_duplicate_referenced_layer_named(
+        void *data = CustomData_duplicate_referenced_layer_named(
             custom_data, stored_type_, layer.name, element_num);
-        if (data_old != data_new) {
-          if (custom_data_access_.update_custom_data_pointers) {
-            custom_data_access_.update_custom_data_pointers(owner);
-          }
-        }
-        return {as_write_attribute_(layer.data, element_num), domain_};
+        return {as_write_attribute_(data, element_num), domain_};
       }
     }
   }
@@ -581,9 +589,6 @@ bool NamedLegacyCustomDataProvider::try_delete(void *owner,
       if (custom_data_layer_matches_attribute_id(layer, attribute_id)) {
         const int element_num = custom_data_access_.get_element_num(owner);
         CustomData_free_layer(custom_data, stored_type_, element_num, i);
-        if (custom_data_access_.update_custom_data_pointers) {
-          custom_data_access_.update_custom_data_pointers(owner);
-        }
         return true;
       }
     }
@@ -698,7 +703,7 @@ bool CustomDataAttributes::create(const AttributeIDRef &attribute_id,
                                   const eCustomDataType data_type)
 {
   void *result = add_generic_custom_data_layer(
-      data, data_type, CD_DEFAULT, nullptr, size_, attribute_id);
+      data, data_type, CD_SET_DEFAULT, nullptr, size_, attribute_id);
   return result != nullptr;
 }
 
@@ -725,8 +730,22 @@ bool CustomDataAttributes::remove(const AttributeIDRef &attribute_id)
 
 void CustomDataAttributes::reallocate(const int size)
 {
+  const int old_size = size_;
   size_ = size;
-  CustomData_realloc(&data, size);
+  CustomData_realloc(&data, old_size, size_);
+  if (size_ > old_size) {
+    /* Fill default new values. */
+    const int new_elements_num = size_ - old_size;
+    this->foreach_attribute(
+        [&](const bke::AttributeIDRef &id, const bke::AttributeMetaData /*meta_data*/) {
+          GMutableSpan new_data = this->get_for_write(id)->take_back(new_elements_num);
+          const CPPType &type = new_data.type();
+          type.fill_assign_n(type.default_value(), new_data.data(), new_data.size());
+          return true;
+        },
+        /* Dummy. */
+        ATTR_DOMAIN_POINT);
+  }
 }
 
 void CustomDataAttributes::clear()
@@ -748,28 +767,8 @@ bool CustomDataAttributes::foreach_attribute(const AttributeForeachCallback call
   return true;
 }
 
-void CustomDataAttributes::reorder(Span new_order)
-{
-  BLI_assert(new_order.size() == data.totlayer);
-
-  Map old_order;
-  old_order.reserve(data.totlayer);
-  Array old_layers(Span(data.layers, data.totlayer));
-  for (const int i : old_layers.index_range()) {
-    old_order.add_new(attribute_id_from_custom_data_layer(old_layers[i]), i);
-  }
-
-  MutableSpan layers(data.layers, data.totlayer);
-  for (const int i : layers.index_range()) {
-    const int old_index = old_order.lookup(new_order[i]);
-    layers[i] = old_layers[old_index];
-  }
-
-  CustomData_update_typemap(&data);
-}
-
 /* -------------------------------------------------------------------- */
-/** \name Geometry Component
+/** \name Attribute API
  * \{ */
 
 static blender::GVArray try_adapt_data_type(blender::GVArray varray,
@@ -780,123 +779,6 @@ static blender::GVArray try_adapt_data_type(blender::GVArray varray,
   return conversions.try_convert(std::move(varray), to_type);
 }
 
-GVArray GeometryFieldInput::get_varray_for_context(const fn::FieldContext &context,
-                                                   IndexMask mask,
-                                                   ResourceScope &UNUSED(scope)) const
-{
-  if (const GeometryComponentFieldContext *geometry_context =
-          dynamic_cast(&context)) {
-    const GeometryComponent &component = geometry_context->geometry_component();
-    const eAttrDomain domain = geometry_context->domain();
-    return this->get_varray_for_context(component, domain, mask);
-  }
-  return {};
-}
-
-GVArray AttributeFieldInput::get_varray_for_context(const GeometryComponent &component,
-                                                    const eAttrDomain domain,
-                                                    IndexMask UNUSED(mask)) const
-{
-  const eCustomDataType data_type = cpp_type_to_custom_data_type(*type_);
-  if (auto attributes = component.attributes()) {
-    return attributes->lookup(name_, domain, data_type);
-  }
-  return {};
-}
-
-std::string AttributeFieldInput::socket_inspection_name() const
-{
-  std::stringstream ss;
-  ss << '"' << name_ << '"' << TIP_(" attribute from geometry");
-  return ss.str();
-}
-
-uint64_t AttributeFieldInput::hash() const
-{
-  return get_default_hash_2(name_, type_);
-}
-
-bool AttributeFieldInput::is_equal_to(const fn::FieldNode &other) const
-{
-  if (const AttributeFieldInput *other_typed = dynamic_cast(&other)) {
-    return name_ == other_typed->name_ && type_ == other_typed->type_;
-  }
-  return false;
-}
-
-static StringRef get_random_id_attribute_name(const eAttrDomain domain)
-{
-  switch (domain) {
-    case ATTR_DOMAIN_POINT:
-    case ATTR_DOMAIN_INSTANCE:
-      return "id";
-    default:
-      return "";
-  }
-}
-
-GVArray IDAttributeFieldInput::get_varray_for_context(const GeometryComponent &component,
-                                                      const eAttrDomain domain,
-                                                      IndexMask mask) const
-{
-
-  const StringRef name = get_random_id_attribute_name(domain);
-  if (auto attributes = component.attributes()) {
-    if (GVArray attribute = attributes->lookup(name, domain, CD_PROP_INT32)) {
-      return attribute;
-    }
-  }
-
-  /* Use the index as the fallback if no random ID attribute exists. */
-  return fn::IndexFieldInput::get_index_varray(mask);
-}
-
-std::string IDAttributeFieldInput::socket_inspection_name() const
-{
-  return TIP_("ID / Index");
-}
-
-uint64_t IDAttributeFieldInput::hash() const
-{
-  /* All random ID attribute inputs are the same within the same evaluation context. */
-  return 92386459827;
-}
-
-bool IDAttributeFieldInput::is_equal_to(const fn::FieldNode &other) const
-{
-  /* All random ID attribute inputs are the same within the same evaluation context. */
-  return dynamic_cast(&other) != nullptr;
-}
-
-GVArray AnonymousAttributeFieldInput::get_varray_for_context(const GeometryComponent &component,
-                                                             const eAttrDomain domain,
-                                                             IndexMask UNUSED(mask)) const
-{
-  const eCustomDataType data_type = cpp_type_to_custom_data_type(*type_);
-  return component.attributes()->lookup(anonymous_id_.get(), domain, data_type);
-}
-
-std::string AnonymousAttributeFieldInput::socket_inspection_name() const
-{
-  std::stringstream ss;
-  ss << '"' << debug_name_ << '"' << TIP_(" from ") << producer_name_;
-  return ss.str();
-}
-
-uint64_t AnonymousAttributeFieldInput::hash() const
-{
-  return get_default_hash_2(anonymous_id_.get(), type_);
-}
-
-bool AnonymousAttributeFieldInput::is_equal_to(const fn::FieldNode &other) const
-{
-  if (const AnonymousAttributeFieldInput *other_typed =
-          dynamic_cast(&other)) {
-    return anonymous_id_.get() == other_typed->anonymous_id_.get() && type_ == other_typed->type_;
-  }
-  return false;
-}
-
 GVArray AttributeAccessor::lookup(const AttributeIDRef &attribute_id,
                                   const std::optional domain,
                                   const std::optional data_type) const
@@ -968,6 +850,59 @@ void MutableAttributeAccessor::remove_anonymous()
   }
 }
 
+/**
+ * Debug utility that checks whether the #finish function of an #AttributeWriter has been called.
+ */
+#ifdef DEBUG
+struct FinishCallChecker {
+  std::string name;
+  bool finish_called = false;
+  std::function real_finish_fn;
+
+  ~FinishCallChecker()
+  {
+    if (!this->finish_called) {
+      std::cerr << "Forgot to call `finish()` for '" << this->name << "'.\n";
+    }
+  }
+};
+#endif
+
+GAttributeWriter MutableAttributeAccessor::lookup_for_write(const AttributeIDRef &attribute_id)
+{
+  GAttributeWriter attribute = fn_->lookup_for_write(owner_, attribute_id);
+  /* Check that the #finish method is called in debug builds. */
+#ifdef DEBUG
+  if (attribute) {
+    auto checker = std::make_shared();
+    if (attribute_id.is_named()) {
+      checker->name = attribute_id.name();
+    }
+    else {
+      checker->name = BKE_anonymous_attribute_id_debug_name(&attribute_id.anonymous_id());
+    }
+    checker->real_finish_fn = attribute.tag_modified_fn;
+    attribute.tag_modified_fn = [checker]() {
+      if (checker->real_finish_fn) {
+        checker->real_finish_fn();
+      }
+      checker->finish_called = true;
+    };
+  }
+#endif
+  return attribute;
+}
+
+GSpanAttributeWriter MutableAttributeAccessor::lookup_for_write_span(
+    const AttributeIDRef &attribute_id)
+{
+  GAttributeWriter attribute = this->lookup_for_write(attribute_id);
+  if (attribute) {
+    return GSpanAttributeWriter{std::move(attribute), true};
+  }
+  return {};
+}
+
 GAttributeWriter MutableAttributeAccessor::lookup_or_add_for_write(
     const AttributeIDRef &attribute_id,
     const eAttrDomain domain,
@@ -1004,13 +939,85 @@ GSpanAttributeWriter MutableAttributeAccessor::lookup_or_add_for_write_span(
 GSpanAttributeWriter MutableAttributeAccessor::lookup_or_add_for_write_only_span(
     const AttributeIDRef &attribute_id, const eAttrDomain domain, const eCustomDataType data_type)
 {
-  GAttributeWriter attribute = this->lookup_or_add_for_write(attribute_id, domain, data_type);
+  GAttributeWriter attribute = this->lookup_or_add_for_write(
+      attribute_id, domain, data_type, AttributeInitConstruct());
   if (attribute) {
     return GSpanAttributeWriter{std::move(attribute), false};
   }
   return {};
 }
 
+fn::GField AttributeValidator::validate_field_if_necessary(const fn::GField &field) const
+{
+  if (function) {
+    auto validate_op = fn::FieldOperation::Create(*function, {field});
+    return fn::GField(validate_op);
+  }
+  return field;
+}
+
+Vector retrieve_attributes_for_transfer(
+    const bke::AttributeAccessor src_attributes,
+    bke::MutableAttributeAccessor dst_attributes,
+    const eAttrDomainMask domain_mask,
+    const Set &skip)
+{
+  Vector attributes;
+  src_attributes.for_all(
+      [&](const bke::AttributeIDRef &id, const bke::AttributeMetaData meta_data) {
+        if (!(ATTR_DOMAIN_AS_MASK(meta_data.domain) & domain_mask)) {
+          return true;
+        }
+        if (id.is_named() && skip.contains(id.name())) {
+          return true;
+        }
+        if (!id.should_be_kept()) {
+          return true;
+        }
+
+        GVArray src = src_attributes.lookup(id, meta_data.domain);
+        BLI_assert(src);
+        bke::GSpanAttributeWriter dst = dst_attributes.lookup_or_add_for_write_only_span(
+            id, meta_data.domain, meta_data.data_type);
+        BLI_assert(dst);
+        attributes.append({std::move(src), meta_data, std::move(dst)});
+
+        return true;
+      });
+  return attributes;
+}
+
+void copy_attribute_domain(const AttributeAccessor src_attributes,
+                           MutableAttributeAccessor dst_attributes,
+                           const IndexMask selection,
+                           const eAttrDomain domain,
+                           const Set &skip)
+{
+  src_attributes.for_all(
+      [&](const bke::AttributeIDRef &id, const bke::AttributeMetaData &meta_data) {
+        if (meta_data.domain != domain) {
+          return true;
+        }
+        if (id.is_named() && skip.contains(id.name())) {
+          return true;
+        }
+        if (!id.should_be_kept()) {
+          return true;
+        }
+
+        const GVArray src = src_attributes.lookup(id, meta_data.domain);
+        BLI_assert(src);
+
+        /* Copy attribute. */
+        GSpanAttributeWriter dst = dst_attributes.lookup_or_add_for_write_only_span(
+            id, domain, meta_data.data_type);
+        array_utils::copy(src, selection, dst.span);
+        dst.finish();
+
+        return true;
+      });
+}
+
 }  // namespace blender::bke
 
 /** \} */
diff --git a/source/blender/blenkernel/intern/attribute_access_intern.hh b/source/blender/blenkernel/intern/attribute_access_intern.hh
index 17432fa2726..5fbca283399 100644
--- a/source/blender/blenkernel/intern/attribute_access_intern.hh
+++ b/source/blender/blenkernel/intern/attribute_access_intern.hh
@@ -23,7 +23,6 @@ struct CustomDataAccessInfo {
   CustomDataGetter get_custom_data;
   ConstCustomDataGetter get_const_custom_data;
   GetElementNum get_element_num;
-  UpdateCustomDataPointers update_custom_data_pointers;
 };
 
 /**
@@ -54,6 +53,7 @@ class BuiltinAttributeProvider {
   const CreatableEnum createable_;
   const WritableEnum writable_;
   const DeletableEnum deletable_;
+  const AttributeValidator validator_;
 
  public:
   BuiltinAttributeProvider(std::string name,
@@ -61,13 +61,15 @@ class BuiltinAttributeProvider {
                            const eCustomDataType data_type,
                            const CreatableEnum createable,
                            const WritableEnum writable,
-                           const DeletableEnum deletable)
+                           const DeletableEnum deletable,
+                           AttributeValidator validator = {})
       : name_(std::move(name)),
         domain_(domain),
         data_type_(data_type),
         createable_(createable),
         writable_(writable),
-        deletable_(deletable)
+        deletable_(deletable),
+        validator_(validator)
   {
   }
 
@@ -91,6 +93,11 @@ class BuiltinAttributeProvider {
   {
     return data_type_;
   }
+
+  AttributeValidator validator() const
+  {
+    return validator_;
+  }
 };
 
 /**
@@ -125,10 +132,7 @@ class DynamicAttributesProvider {
  */
 class CustomDataAttributeProvider final : public DynamicAttributesProvider {
  private:
-  static constexpr uint64_t supported_types_mask = CD_MASK_PROP_FLOAT | CD_MASK_PROP_FLOAT2 |
-                                                   CD_MASK_PROP_FLOAT3 | CD_MASK_PROP_INT32 |
-                                                   CD_MASK_PROP_COLOR | CD_MASK_PROP_BOOL |
-                                                   CD_MASK_PROP_INT8 | CD_MASK_PROP_BYTE_COLOR;
+  static constexpr uint64_t supported_types_mask = CD_MASK_PROP_ALL;
   const eAttrDomain domain_;
   const CustomDataAccessInfo custom_data_access_;
 
@@ -226,12 +230,12 @@ class BuiltinCustomDataLayerProvider final : public BuiltinAttributeProvider {
   using AsReadAttribute = GVArray (*)(const void *data, int element_num);
   using AsWriteAttribute = GVMutableArray (*)(void *data, int element_num);
   using UpdateOnRead = void (*)(const void *owner);
-  using UpdateOnWrite = void (*)(void *owner);
+  using UpdateOnChange = void (*)(void *owner);
   const eCustomDataType stored_type_;
   const CustomDataAccessInfo custom_data_access_;
   const AsReadAttribute as_read_attribute_;
   const AsWriteAttribute as_write_attribute_;
-  const UpdateOnWrite update_on_write_;
+  const UpdateOnChange update_on_change_;
   bool stored_as_named_attribute_;
 
  public:
@@ -245,14 +249,20 @@ class BuiltinCustomDataLayerProvider final : public BuiltinAttributeProvider {
                                  const CustomDataAccessInfo custom_data_access,
                                  const AsReadAttribute as_read_attribute,
                                  const AsWriteAttribute as_write_attribute,
-                                 const UpdateOnWrite update_on_write)
-      : BuiltinAttributeProvider(
-            std::move(attribute_name), domain, attribute_type, creatable, writable, deletable),
+                                 const UpdateOnChange update_on_write,
+                                 const AttributeValidator validator = {})
+      : BuiltinAttributeProvider(std::move(attribute_name),
+                                 domain,
+                                 attribute_type,
+                                 creatable,
+                                 writable,
+                                 deletable,
+                                 validator),
         stored_type_(stored_type),
         custom_data_access_(custom_data_access),
         as_read_attribute_(as_read_attribute),
         as_write_attribute_(as_write_attribute),
-        update_on_write_(update_on_write),
+        update_on_change_(update_on_write),
         stored_as_named_attribute_(data_type_ == stored_type_)
   {
   }
@@ -262,6 +272,9 @@ class BuiltinCustomDataLayerProvider final : public BuiltinAttributeProvider {
   bool try_delete(void *owner) const final;
   bool try_create(void *owner, const AttributeInit &initializer) const final;
   bool exists(const void *owner) const final;
+
+ private:
+  bool layer_exists(const CustomData &custom_data) const;
 };
 
 /**
@@ -379,6 +392,21 @@ inline bool for_all(const void *owner,
   return true;
 }
 
+template
+inline AttributeValidator lookup_validator(const void * /*owner*/,
+                                           const blender::bke::AttributeIDRef &attribute_id)
+{
+  if (!attribute_id.is_named()) {
+    return {};
+  }
+  const BuiltinAttributeProvider *provider =
+      providers.builtin_attribute_providers().lookup_default_as(attribute_id.name(), nullptr);
+  if (!provider) {
+    return {};
+  }
+  return provider->validator();
+}
+
 template
 inline bool contains(const void *owner, const blender::bke::AttributeIDRef &attribute_id)
 {
@@ -490,6 +518,7 @@ inline AttributeAccessorFunctions accessor_functions_for_providers()
                                     lookup,
                                     nullptr,
                                     for_all,
+                                    lookup_validator,
                                     lookup_for_write,
                                     remove,
                                     add};
diff --git a/source/blender/blenkernel/intern/attribute_math.cc b/source/blender/blenkernel/intern/attribute_math.cc
index c38df2a2969..d8102b4eeb8 100644
--- a/source/blender/blenkernel/intern/attribute_math.cc
+++ b/source/blender/blenkernel/intern/attribute_math.cc
@@ -4,13 +4,31 @@
 
 namespace blender::attribute_math {
 
-ColorGeometry4fMixer::ColorGeometry4fMixer(MutableSpan output_buffer,
+ColorGeometry4fMixer::ColorGeometry4fMixer(MutableSpan buffer,
                                            ColorGeometry4f default_color)
-    : buffer_(output_buffer),
-      default_color_(default_color),
-      total_weights_(output_buffer.size(), 0.0f)
+    : ColorGeometry4fMixer(buffer, buffer.index_range(), default_color)
+{
+}
+
+ColorGeometry4fMixer::ColorGeometry4fMixer(MutableSpan buffer,
+                                           const IndexMask mask,
+                                           const ColorGeometry4f default_color)
+    : buffer_(buffer), default_color_(default_color), total_weights_(buffer.size(), 0.0f)
 {
-  buffer_.fill(ColorGeometry4f(0.0f, 0.0f, 0.0f, 0.0f));
+  const ColorGeometry4f zero{0.0f, 0.0f, 0.0f, 0.0f};
+  mask.foreach_index([&](const int64_t i) { buffer_[i] = zero; });
+}
+
+void ColorGeometry4fMixer::set(const int64_t index,
+                               const ColorGeometry4f &color,
+                               const float weight)
+{
+  BLI_assert(weight >= 0.0f);
+  buffer_[index].r = color.r * weight;
+  buffer_[index].g = color.g * weight;
+  buffer_[index].b = color.b * weight;
+  buffer_[index].a = color.a * weight;
+  total_weights_[index] = weight;
 }
 
 void ColorGeometry4fMixer::mix_in(const int64_t index,
@@ -28,7 +46,12 @@ void ColorGeometry4fMixer::mix_in(const int64_t index,
 
 void ColorGeometry4fMixer::finalize()
 {
-  for (const int64_t i : buffer_.index_range()) {
+  this->finalize(buffer_.index_range());
+}
+
+void ColorGeometry4fMixer::finalize(const IndexMask mask)
+{
+  mask.foreach_index([&](const int64_t i) {
     const float weight = total_weights_[i];
     ColorGeometry4f &output_color = buffer_[i];
     if (weight > 0.0f) {
@@ -41,16 +64,37 @@ void ColorGeometry4fMixer::finalize()
     else {
       output_color = default_color_;
     }
-  }
+  });
 }
 
 ColorGeometry4bMixer::ColorGeometry4bMixer(MutableSpan buffer,
-                                           ColorGeometry4b default_color)
+                                           const ColorGeometry4b default_color)
+    : ColorGeometry4bMixer(buffer, buffer.index_range(), default_color)
+{
+}
+
+ColorGeometry4bMixer::ColorGeometry4bMixer(MutableSpan buffer,
+                                           const IndexMask mask,
+                                           const ColorGeometry4b default_color)
     : buffer_(buffer),
       default_color_(default_color),
       total_weights_(buffer.size(), 0.0f),
       accumulation_buffer_(buffer.size(), float4(0, 0, 0, 0))
 {
+  const ColorGeometry4b zero{0, 0, 0, 0};
+  mask.foreach_index([&](const int64_t i) { buffer_[i] = zero; });
+}
+
+void ColorGeometry4bMixer::ColorGeometry4bMixer::set(int64_t index,
+                                                     const ColorGeometry4b &color,
+                                                     const float weight)
+{
+  BLI_assert(weight >= 0.0f);
+  accumulation_buffer_[index][0] = color.r * weight;
+  accumulation_buffer_[index][1] = color.g * weight;
+  accumulation_buffer_[index][2] = color.b * weight;
+  accumulation_buffer_[index][3] = color.a * weight;
+  total_weights_[index] = weight;
 }
 
 void ColorGeometry4bMixer::mix_in(int64_t index, const ColorGeometry4b &color, float weight)
@@ -66,7 +110,12 @@ void ColorGeometry4bMixer::mix_in(int64_t index, const ColorGeometry4b &color, f
 
 void ColorGeometry4bMixer::finalize()
 {
-  for (const int64_t i : buffer_.index_range()) {
+  this->finalize(buffer_.index_range());
+}
+
+void ColorGeometry4bMixer::finalize(const IndexMask mask)
+{
+  mask.foreach_index([&](const int64_t i) {
     const float weight = total_weights_[i];
     const float4 &accum_value = accumulation_buffer_[i];
     ColorGeometry4b &output_color = buffer_[i];
@@ -80,7 +129,7 @@ void ColorGeometry4bMixer::finalize()
     else {
       output_color = default_color_;
     }
-  }
+  });
 }
 
 }  // namespace blender::attribute_math
diff --git a/source/blender/blenkernel/intern/blender_copybuffer.c b/source/blender/blenkernel/intern/blender_copybuffer.c
index 4b507beb6b3..82df2714a71 100644
--- a/source/blender/blenkernel/intern/blender_copybuffer.c
+++ b/source/blender/blenkernel/intern/blender_copybuffer.c
@@ -150,7 +150,7 @@ int BKE_copybuffer_paste(bContext *C,
     return 0;
   }
 
-  BKE_view_layer_base_deselect_all(view_layer);
+  BKE_view_layer_base_deselect_all(scene, view_layer);
 
   copybuffer_append(lapp_context, bmain, reports);
 
diff --git a/source/blender/blenkernel/intern/blendfile.c b/source/blender/blenkernel/intern/blendfile.c
index 70c3dc2de39..bf40d07054d 100644
--- a/source/blender/blenkernel/intern/blendfile.c
+++ b/source/blender/blenkernel/intern/blendfile.c
@@ -364,7 +364,7 @@ static void setup_app_data(bContext *C,
     BKE_lib_override_library_main_hierarchy_root_ensure(bmain);
   }
 
-  bmain->recovered = 0;
+  bmain->recovered = false;
 
   /* startup.blend or recovered startup */
   if (is_startup) {
@@ -372,7 +372,7 @@ static void setup_app_data(bContext *C,
   }
   else if (recover) {
     /* In case of autosave or quit.blend, use original filepath instead. */
-    bmain->recovered = 1;
+    bmain->recovered = true;
     STRNCPY(bmain->filepath, bfd->filepath);
   }
 
@@ -453,7 +453,7 @@ static void handle_subversion_warning(Main *main, BlendFileReadReport *reports)
       (main->minversionfile == BLENDER_FILE_VERSION &&
        main->minsubversionfile > BLENDER_FILE_SUBVERSION)) {
     BKE_reportf(reports->reports,
-                RPT_ERROR,
+                RPT_WARNING,
                 "File written by newer Blender binary (%d.%d), expect loss of data!",
                 main->minversionfile,
                 main->minsubversionfile);
diff --git a/source/blender/blenkernel/intern/blendfile_link_append.c b/source/blender/blenkernel/intern/blendfile_link_append.c
index ebf48acde0f..e3b76122ff0 100644
--- a/source/blender/blenkernel/intern/blendfile_link_append.c
+++ b/source/blender/blenkernel/intern/blendfile_link_append.c
@@ -493,6 +493,7 @@ static void loose_data_instantiate_ensure_active_collection(
 static void loose_data_instantiate_object_base_instance_init(Main *bmain,
                                                              Collection *collection,
                                                              Object *ob,
+                                                             const Scene *scene,
                                                              ViewLayer *view_layer,
                                                              const View3D *v3d,
                                                              const int flag,
@@ -506,7 +507,7 @@ static void loose_data_instantiate_object_base_instance_init(Main *bmain,
   }
 
   BKE_collection_object_add(bmain, collection, ob);
-
+  BKE_view_layer_synced_ensure(scene, view_layer);
   Base *base = BKE_view_layer_base_find(view_layer, ob);
 
   if (v3d != NULL) {
@@ -686,8 +687,14 @@ static void loose_data_instantiate_collection_process(
       /* TODO: why is it OK to make this active here but not in other situations?
        * See other callers of #object_base_instance_init */
       const bool set_active = set_selected;
-      loose_data_instantiate_object_base_instance_init(
-          bmain, active_collection, ob, view_layer, v3d, lapp_context->params->flag, set_active);
+      loose_data_instantiate_object_base_instance_init(bmain,
+                                                       active_collection,
+                                                       ob,
+                                                       scene,
+                                                       view_layer,
+                                                       v3d,
+                                                       lapp_context->params->flag,
+                                                       set_active);
 
       /* Assign the collection. */
       ob->instance_collection = collection;
@@ -698,6 +705,7 @@ static void loose_data_instantiate_collection_process(
     else {
       /* Add collection as child of active collection. */
       BKE_collection_child_add(bmain, active_collection, collection);
+      BKE_view_layer_synced_ensure(scene, view_layer);
 
       if ((lapp_context->params->flag & FILE_AUTOSELECT) != 0) {
         LISTBASE_FOREACH (CollectionObject *, coll_ob, &collection->gobject) {
@@ -717,6 +725,7 @@ static void loose_data_instantiate_object_process(LooseDataInstantiateContext *i
 {
   BlendfileLinkAppendContext *lapp_context = instantiate_context->lapp_context;
   Main *bmain = lapp_context->params->bmain;
+  const Scene *scene = lapp_context->params->context.scene;
   ViewLayer *view_layer = lapp_context->params->context.view_layer;
   const View3D *v3d = lapp_context->params->context.v3d;
 
@@ -762,6 +771,7 @@ static void loose_data_instantiate_object_process(LooseDataInstantiateContext *i
     loose_data_instantiate_object_base_instance_init(bmain,
                                                      active_collection,
                                                      ob,
+                                                     scene,
                                                      view_layer,
                                                      v3d,
                                                      lapp_context->params->flag,
@@ -809,6 +819,7 @@ static void loose_data_instantiate_obdata_process(LooseDataInstantiateContext *i
     loose_data_instantiate_object_base_instance_init(bmain,
                                                      active_collection,
                                                      ob,
+                                                     scene,
                                                      view_layer,
                                                      v3d,
                                                      lapp_context->params->flag,
@@ -1232,8 +1243,9 @@ void BKE_blendfile_link(BlendfileLinkAppendContext *lapp_context, ReportList *re
 
     mainl = BLO_library_link_begin(&blo_handle, libname, lapp_context->params);
     lib = mainl->curlib;
-    BLI_assert(lib);
-    UNUSED_VARS_NDEBUG(lib);
+    BLI_assert(lib != NULL);
+    /* In case lib was already existing but not found originally, see T99820. */
+    lib->id.tag &= ~LIB_TAG_MISSING;
 
     if (mainl->versionfile < 250) {
       BKE_reportf(reports,
diff --git a/source/blender/blenkernel/intern/boids.c b/source/blender/blenkernel/intern/boids.c
index a86d6e25ee9..2e07b52c7bf 100644
--- a/source/blender/blenkernel/intern/boids.c
+++ b/source/blender/blenkernel/intern/boids.c
@@ -1567,7 +1567,7 @@ void boid_body(BoidBrainData *bbd, ParticleData *pa)
   cross_v3_v3v3(mat[1], mat[2], mat[0]);
 
   /* apply rotation */
-  mat3_to_quat_is_ok(q, mat);
+  mat3_to_quat_legacy(q, mat);
   copy_qt_qt(pa->state.rot, q);
 }
 
diff --git a/source/blender/blenkernel/intern/brush.cc b/source/blender/blenkernel/intern/brush.cc
index ffa63f9792f..a998fc0a75f 100644
--- a/source/blender/blenkernel/intern/brush.cc
+++ b/source/blender/blenkernel/intern/brush.cc
@@ -186,6 +186,7 @@ static void brush_foreach_id(ID *id, LibraryForeachIDData *data)
   BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, brush->paint_curve, IDWALK_CB_USER);
   if (brush->gpencil_settings) {
     BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, brush->gpencil_settings->material, IDWALK_CB_USER);
+    BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, brush->gpencil_settings->material_alt, IDWALK_CB_USER);
   }
   BKE_LIB_FOREACHID_PROCESS_FUNCTION_CALL(data, BKE_texture_mtex_foreach_id(data, &brush->mtex));
   BKE_LIB_FOREACHID_PROCESS_FUNCTION_CALL(data,
@@ -346,6 +347,7 @@ static void brush_blend_read_lib(BlendLibReader *reader, ID *id)
     else {
       brush->gpencil_settings->material = nullptr;
     }
+    BLO_read_id_address(reader, brush->id.lib, &brush->gpencil_settings->material_alt);
   }
 }
 
@@ -358,6 +360,7 @@ static void brush_blend_read_expand(BlendExpander *expander, ID *id)
   BLO_expand(expander, brush->paint_curve);
   if (brush->gpencil_settings != nullptr) {
     BLO_expand(expander, brush->gpencil_settings->material);
+    BLO_expand(expander, brush->gpencil_settings->material_alt);
   }
 }
 
@@ -410,7 +413,7 @@ IDTypeInfo IDType_ID_BR = {
     /* foreach_id */ brush_foreach_id,
     /* foreach_cache */ nullptr,
     /* foreach_path */ brush_foreach_path,
-    /* owner_get */ nullptr,
+    /* owner_pointer_get */ nullptr,
 
     /* blend_write */ brush_blend_write,
     /* blend_read_data */ brush_blend_read_data,
@@ -444,7 +447,8 @@ static void brush_defaults(Brush *brush)
 
   const Brush *brush_def = DNA_struct_default_get(Brush);
 
-#define FROM_DEFAULT(member) memcpy(&brush->member, &brush_def->member, sizeof(brush->member))
+#define FROM_DEFAULT(member) \
+  memcpy((void *)&brush->member, (void *)&brush_def->member, sizeof(brush->member))
 #define FROM_DEFAULT_PTR(member) memcpy(brush->member, brush_def->member, sizeof(brush->member))
 
   FROM_DEFAULT(blend);
@@ -586,17 +590,17 @@ bool BKE_brush_delete(Main *bmain, Brush *brush)
   return true;
 }
 
-/* grease pencil cumapping->preset */
-typedef enum eGPCurveMappingPreset {
+/** Local grease pencil curve mapping preset. */
+using eGPCurveMappingPreset = enum eGPCurveMappingPreset {
   GPCURVE_PRESET_PENCIL = 0,
   GPCURVE_PRESET_INK = 1,
   GPCURVE_PRESET_INKNOISE = 2,
   GPCURVE_PRESET_MARKER = 3,
   GPCURVE_PRESET_CHISEL_SENSIVITY = 4,
   GPCURVE_PRESET_CHISEL_STRENGTH = 5,
-} eGPCurveMappingPreset;
+};
 
-static void brush_gpencil_curvemap_reset(CurveMap *cuma, int tot, int preset)
+static void brush_gpencil_curvemap_reset(CurveMap *cuma, int tot, eGPCurveMappingPreset preset)
 {
   if (cuma->curve) {
     MEM_freeN(cuma->curve);
@@ -703,6 +707,7 @@ void BKE_gpencil_brush_preset_set(Main *bmain, Brush *brush, const short type)
   /* Set vertex mix factor. */
   brush->gpencil_settings->vertex_mode = GPPAINT_MODE_BOTH;
   brush->gpencil_settings->vertex_factor = 1.0f;
+  brush->gpencil_settings->material_alt = nullptr;
 
   switch (type) {
     case GP_BRUSH_PRESET_AIRBRUSH: {
@@ -977,7 +982,6 @@ void BKE_gpencil_brush_preset_set(Main *bmain, Brush *brush, const short type)
     case GP_BRUSH_PRESET_FILL_AREA: {
       brush->size = 5.0f;
 
-      brush->gpencil_settings->fill_leak = 3;
       brush->gpencil_settings->fill_threshold = 0.1f;
       brush->gpencil_settings->fill_simplylvl = 1;
       brush->gpencil_settings->fill_factor = 1.0f;
@@ -2511,8 +2515,10 @@ struct ImBuf *BKE_brush_gen_radial_control_imbuf(Brush *br, bool secondary, bool
   if (display_gradient || have_texture) {
     for (int i = 0; i < side; i++) {
       for (int j = 0; j < side; j++) {
-        float magn = sqrtf(pow2f(i - half) + pow2f(j - half));
-        im->rect_float[i * side + j] *= BKE_brush_curve_strength_clamped(br, magn, half);
+        const float magn = sqrtf(pow2f(i - half) + pow2f(j - half));
+        const float strength = BKE_brush_curve_strength_clamped(br, magn, half);
+        im->rect_float[i * side + j] = (have_texture) ? im->rect_float[i * side + j] * strength :
+                                                        strength;
       }
     }
   }
diff --git a/source/blender/blenkernel/intern/bvhutils.cc b/source/blender/blenkernel/intern/bvhutils.cc
index 35c2039634a..9bea8a0d6d3 100644
--- a/source/blender/blenkernel/intern/bvhutils.cc
+++ b/source/blender/blenkernel/intern/bvhutils.cc
@@ -15,10 +15,12 @@
 
 #include "BLI_linklist.h"
 #include "BLI_math.h"
+#include "BLI_span.hh"
 #include "BLI_task.h"
 #include "BLI_threads.h"
 #include "BLI_utildefines.h"
 
+#include "BKE_attribute.hh"
 #include "BKE_bvhutils.h"
 #include "BKE_editmesh.h"
 #include "BKE_mesh.h"
@@ -26,6 +28,9 @@
 
 #include "MEM_guardedalloc.h"
 
+using blender::Span;
+using blender::VArray;
+
 /* -------------------------------------------------------------------- */
 /** \name BVHCache
  * \{ */
@@ -1180,9 +1185,13 @@ static BLI_bitmap *loose_edges_map_get(const MEdge *medge,
 }
 
 static BLI_bitmap *looptri_no_hidden_map_get(const MPoly *mpoly,
+                                             const VArray &hide_poly,
                                              const int looptri_len,
                                              int *r_looptri_active_len)
 {
+  if (hide_poly.is_single() && !hide_poly.get_internal_single()) {
+    return nullptr;
+  }
   BLI_bitmap *looptri_mask = BLI_BITMAP_NEW(looptri_len, __func__);
 
   int looptri_no_hidden_len = 0;
@@ -1190,8 +1199,7 @@ static BLI_bitmap *looptri_no_hidden_map_get(const MPoly *mpoly,
   int i_poly = 0;
   while (looptri_iter != looptri_len) {
     int mp_totlooptri = mpoly[i_poly].totloop - 2;
-    const MPoly &mp = mpoly[i_poly];
-    if (mp.flag & ME_HIDE) {
+    if (hide_poly[i_poly]) {
       looptri_iter += mp_totlooptri;
     }
     else {
@@ -1223,14 +1231,17 @@ BVHTree *BKE_bvhtree_from_mesh_get(struct BVHTreeFromMesh *data,
     looptri = BKE_mesh_runtime_looptri_ensure(mesh);
     looptri_len = BKE_mesh_runtime_looptri_len(mesh);
   }
+  const Span verts = mesh->verts();
+  const Span edges = mesh->edges();
+  const Span loops = mesh->loops();
 
   /* Setup BVHTreeFromMesh */
   bvhtree_from_mesh_setup_data(nullptr,
                                bvh_cache_type,
-                               mesh->mvert,
-                               mesh->medge,
-                               mesh->mface,
-                               mesh->mloop,
+                               verts.data(),
+                               edges.data(),
+                               (const MFace *)CustomData_get_layer(&mesh->fdata, CD_MFACE),
+                               loops.data(),
                                looptri,
                                BKE_mesh_vertex_normals_ensure(mesh),
                                data);
@@ -1254,36 +1265,49 @@ BVHTree *BKE_bvhtree_from_mesh_get(struct BVHTreeFromMesh *data,
   switch (bvh_cache_type) {
     case BVHTREE_FROM_LOOSEVERTS:
       mask = loose_verts_map_get(
-          mesh->medge, mesh->totedge, mesh->mvert, mesh->totvert, &mask_bits_act_len);
+          edges.data(), mesh->totedge, verts.data(), mesh->totvert, &mask_bits_act_len);
       ATTR_FALLTHROUGH;
     case BVHTREE_FROM_VERTS:
       data->tree = bvhtree_from_mesh_verts_create_tree(
-          0.0f, tree_type, 6, mesh->mvert, mesh->totvert, mask, mask_bits_act_len);
+          0.0f, tree_type, 6, verts.data(), mesh->totvert, mask, mask_bits_act_len);
       break;
 
     case BVHTREE_FROM_LOOSEEDGES:
-      mask = loose_edges_map_get(mesh->medge, mesh->totedge, &mask_bits_act_len);
+      mask = loose_edges_map_get(edges.data(), mesh->totedge, &mask_bits_act_len);
       ATTR_FALLTHROUGH;
     case BVHTREE_FROM_EDGES:
       data->tree = bvhtree_from_mesh_edges_create_tree(
-          mesh->mvert, mesh->medge, mesh->totedge, mask, mask_bits_act_len, 0.0f, tree_type, 6);
+          verts.data(), edges.data(), mesh->totedge, mask, mask_bits_act_len, 0.0f, tree_type, 6);
       break;
 
     case BVHTREE_FROM_FACES:
       BLI_assert(!(mesh->totface == 0 && mesh->totpoly != 0));
       data->tree = bvhtree_from_mesh_faces_create_tree(
-          0.0f, tree_type, 6, mesh->mvert, mesh->mface, mesh->totface, nullptr, -1);
+          0.0f,
+          tree_type,
+          6,
+          verts.data(),
+          (const MFace *)CustomData_get_layer(&mesh->fdata, CD_MFACE),
+          mesh->totface,
+          nullptr,
+          -1);
       break;
 
-    case BVHTREE_FROM_LOOPTRI_NO_HIDDEN:
-      mask = looptri_no_hidden_map_get(mesh->mpoly, looptri_len, &mask_bits_act_len);
+    case BVHTREE_FROM_LOOPTRI_NO_HIDDEN: {
+      blender::bke::AttributeAccessor attributes = mesh->attributes();
+      mask = looptri_no_hidden_map_get(
+          mesh->polys().data(),
+          attributes.lookup_or_default(".hide_poly", ATTR_DOMAIN_FACE, false),
+          looptri_len,
+          &mask_bits_act_len);
       ATTR_FALLTHROUGH;
+    }
     case BVHTREE_FROM_LOOPTRI:
       data->tree = bvhtree_from_mesh_looptri_create_tree(0.0f,
                                                          tree_type,
                                                          6,
-                                                         mesh->mvert,
-                                                         mesh->mloop,
+                                                         verts.data(),
+                                                         loops.data(),
                                                          looptri,
                                                          looptri_len,
                                                          mask,
@@ -1430,13 +1454,17 @@ BVHTree *BKE_bvhtree_from_pointcloud_get(BVHTreeFromPointCloud *data,
     return nullptr;
   }
 
-  for (int i = 0; i < pointcloud->totpoint; i++) {
-    BLI_bvhtree_insert(tree, i, pointcloud->co[i], 1);
+  blender::bke::AttributeAccessor attributes = pointcloud->attributes();
+  blender::VArraySpan positions = attributes.lookup_or_default(
+      "position", ATTR_DOMAIN_POINT, blender::float3(0));
+
+  for (const int i : positions.index_range()) {
+    BLI_bvhtree_insert(tree, i, positions[i], 1);
   }
   BLI_assert(BLI_bvhtree_get_len(tree) == pointcloud->totpoint);
   bvhtree_balance(tree, false);
 
-  data->coords = pointcloud->co;
+  data->coords = (const float(*)[3])positions.data();
   data->tree = tree;
   data->nearest_callback = nullptr;
 
diff --git a/source/blender/blenkernel/intern/cachefile.c b/source/blender/blenkernel/intern/cachefile.c
index 6b6b7223a0b..5d19db323f8 100644
--- a/source/blender/blenkernel/intern/cachefile.c
+++ b/source/blender/blenkernel/intern/cachefile.c
@@ -146,7 +146,7 @@ IDTypeInfo IDType_ID_CF = {
     .foreach_id = NULL,
     .foreach_cache = NULL,
     .foreach_path = cache_file_foreach_path,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = cache_file_blend_write,
     .blend_read_data = cache_file_blend_read_data,
@@ -429,10 +429,10 @@ bool BKE_cache_file_uses_render_procedural(const CacheFile *cache_file, Scene *s
   return cache_file->use_render_procedural;
 }
 
-CacheFileLayer *BKE_cachefile_add_layer(CacheFile *cache_file, const char filename[1024])
+CacheFileLayer *BKE_cachefile_add_layer(CacheFile *cache_file, const char filepath[1024])
 {
   for (CacheFileLayer *layer = cache_file->layers.first; layer; layer = layer->next) {
-    if (STREQ(layer->filepath, filename)) {
+    if (STREQ(layer->filepath, filepath)) {
       return NULL;
     }
   }
@@ -440,7 +440,7 @@ CacheFileLayer *BKE_cachefile_add_layer(CacheFile *cache_file, const char filena
   const int num_layers = BLI_listbase_count(&cache_file->layers);
 
   CacheFileLayer *layer = MEM_callocN(sizeof(CacheFileLayer), "CacheFileLayer");
-  BLI_strncpy(layer->filepath, filename, sizeof(layer->filepath));
+  BLI_strncpy(layer->filepath, filepath, sizeof(layer->filepath));
 
   BLI_addtail(&cache_file->layers, layer);
 
diff --git a/source/blender/blenkernel/intern/camera.c b/source/blender/blenkernel/intern/camera.c
index fbe03ac365c..c3384239cb6 100644
--- a/source/blender/blenkernel/intern/camera.c
+++ b/source/blender/blenkernel/intern/camera.c
@@ -25,6 +25,7 @@
 #include "BLI_string.h"
 #include "BLI_utildefines.h"
 
+#include "BKE_action.h"
 #include "BKE_anim_data.h"
 #include "BKE_camera.h"
 #include "BKE_idtype.h"
@@ -71,7 +72,7 @@ static void camera_copy_data(Main *UNUSED(bmain), ID *id_dst, const ID *id_src,
   Camera *cam_dst = (Camera *)id_dst;
   const Camera *cam_src = (const Camera *)id_src;
 
-  /* We never handle usercount here for own data. */
+  /* We never handle user-count here for own data. */
   const int flag_subdata = flag | LIB_ID_CREATE_NO_USER_REFCOUNT;
 
   BLI_listbase_clear(&cam_dst->bg_images);
@@ -185,7 +186,7 @@ IDTypeInfo IDType_ID_CA = {
     .foreach_id = camera_foreach_id,
     .foreach_cache = NULL,
     .foreach_path = NULL,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = camera_blend_write,
     .blend_read_data = camera_blend_read_data,
@@ -221,7 +222,16 @@ float BKE_camera_object_dof_distance(const Object *ob)
   if (cam->dof.focus_object) {
     float view_dir[3], dof_dir[3];
     normalize_v3_v3(view_dir, ob->obmat[2]);
-    sub_v3_v3v3(dof_dir, ob->obmat[3], cam->dof.focus_object->obmat[3]);
+    bPoseChannel *pchan = BKE_pose_channel_find_name(cam->dof.focus_object->pose,
+                                                     cam->dof.focus_subtarget);
+    if (pchan) {
+      float posemat[4][4];
+      mul_m4_m4m4(posemat, cam->dof.focus_object->obmat, pchan->pose_mat);
+      sub_v3_v3v3(dof_dir, ob->obmat[3], posemat[3]);
+    }
+    else {
+      sub_v3_v3v3(dof_dir, ob->obmat[3], cam->dof.focus_object->obmat[3]);
+    }
     return fabsf(dot_v3v3(view_dir, dof_dir));
   }
   return cam->dof.focus_distance;
@@ -340,7 +350,7 @@ void BKE_camera_params_from_view3d(CameraParams *params,
     /* orthographic view */
     float sensor_size = BKE_camera_sensor_size(
         params->sensor_fit, params->sensor_x, params->sensor_y);
-    /* Halve, otherwise too extreme low zbuffer quality. */
+    /* Halve, otherwise too extreme low Z-buffer quality. */
     params->clip_end *= 0.5f;
     params->clip_start = -params->clip_end;
 
@@ -391,7 +401,7 @@ void BKE_camera_params_compute_viewplane(
   pixsize *= params->zoom;
 
   /* compute view plane:
-   * fully centered, zbuffer fills in jittered between -.5 and +.5 */
+   * Fully centered, Z-buffer fills in jittered between `-.5` and `+.5`. */
   viewplane.xmin = -0.5f * (float)winx;
   viewplane.ymin = -0.5f * params->ycor * (float)winy;
   viewplane.xmax = 0.5f * (float)winx;
@@ -559,6 +569,11 @@ void BKE_camera_view_frame(const Scene *scene, const Camera *camera, float r_vec
 
 #define CAMERA_VIEWFRAME_NUM_PLANES 4
 
+#define Y_MIN 0
+#define Y_MAX 1
+#define Z_MIN 2
+#define Z_MAX 3
+
 typedef struct CameraViewFrameData {
   float plane_tx[CAMERA_VIEWFRAME_NUM_PLANES][4]; /* 4 planes normalized */
   float dist_vals[CAMERA_VIEWFRAME_NUM_PLANES];   /* distance (signed) */
@@ -622,15 +637,13 @@ static void camera_frame_fit_data_init(const Scene *scene,
   invert_m4(camera_rotmat_transposed_inversed);
 
   /* Extract frustum planes from projection matrix. */
-  planes_from_projmat(
-      params->winmat,
-      /*   left              right                 top              bottom        near  far */
-      data->plane_tx[2],
-      data->plane_tx[0],
-      data->plane_tx[3],
-      data->plane_tx[1],
-      NULL,
-      NULL);
+  planes_from_projmat(params->winmat,
+                      data->plane_tx[Y_MIN],
+                      data->plane_tx[Y_MAX],
+                      data->plane_tx[Z_MIN],
+                      data->plane_tx[Z_MAX],
+                      NULL,
+                      NULL);
 
   /* Rotate planes and get normals from them */
   for (uint i = 0; i < CAMERA_VIEWFRAME_NUM_PLANES; i++) {
@@ -670,21 +683,21 @@ static bool camera_frame_fit_calc_from_data(CameraParams *params,
     const float *cam_axis_y = data->camera_rotmat[1];
     const float *cam_axis_z = data->camera_rotmat[2];
     const float *dists = data->dist_vals;
-    float scale_diff;
+    const float dist_span_y = dists[Y_MIN] + dists[Y_MAX];
+    const float dist_span_z = dists[Z_MIN] + dists[Z_MAX];
+    const float dist_mid_y = (dists[Y_MIN] - dists[Y_MAX]) * 0.5f;
+    const float dist_mid_z = (dists[Z_MIN] - dists[Z_MAX]) * 0.5f;
+    const float scale_diff = (dist_span_z < dist_span_y) ?
+                                 (dist_span_z * (BLI_rctf_size_x(¶ms->viewplane) /
+                                                 BLI_rctf_size_y(¶ms->viewplane))) :
+                                 (dist_span_y * (BLI_rctf_size_y(¶ms->viewplane) /
+                                                 BLI_rctf_size_x(¶ms->viewplane)));
 
-    if ((dists[0] + dists[2]) > (dists[1] + dists[3])) {
-      scale_diff = (dists[1] + dists[3]) *
-                   (BLI_rctf_size_x(¶ms->viewplane) / BLI_rctf_size_y(¶ms->viewplane));
-    }
-    else {
-      scale_diff = (dists[0] + dists[2]) *
-                   (BLI_rctf_size_y(¶ms->viewplane) / BLI_rctf_size_x(¶ms->viewplane));
-    }
     *r_scale = params->ortho_scale - scale_diff;
 
     zero_v3(r_co);
-    madd_v3_v3fl(r_co, cam_axis_x, (dists[2] - dists[0]) * 0.5f + params->shiftx * scale_diff);
-    madd_v3_v3fl(r_co, cam_axis_y, (dists[1] - dists[3]) * 0.5f + params->shifty * scale_diff);
+    madd_v3_v3fl(r_co, cam_axis_x, dist_mid_y + (params->shiftx * scale_diff));
+    madd_v3_v3fl(r_co, cam_axis_y, dist_mid_z + (params->shifty * scale_diff));
     madd_v3_v3fl(r_co, cam_axis_z, -(data->z_range[0] - 1.0f - params->clip_start));
   }
   else {
@@ -700,36 +713,37 @@ static bool camera_frame_fit_calc_from_data(CameraParams *params,
       plane_from_point_normal_v3(plane_tx[i], co, data->plane_tx[i]);
     }
 
-    if ((!isect_plane_plane_v3(plane_tx[0], plane_tx[2], plane_isect_1, plane_isect_1_no)) ||
-        (!isect_plane_plane_v3(plane_tx[1], plane_tx[3], plane_isect_2, plane_isect_2_no))) {
+    if ((!isect_plane_plane_v3(
+            plane_tx[Y_MIN], plane_tx[Y_MAX], plane_isect_1, plane_isect_1_no)) ||
+        (!isect_plane_plane_v3(
+            plane_tx[Z_MIN], plane_tx[Z_MAX], plane_isect_2, plane_isect_2_no))) {
       return false;
     }
 
     add_v3_v3v3(plane_isect_1_other, plane_isect_1, plane_isect_1_no);
     add_v3_v3v3(plane_isect_2_other, plane_isect_2, plane_isect_2_no);
 
-    if (isect_line_line_v3(plane_isect_1,
-                           plane_isect_1_other,
-                           plane_isect_2,
-                           plane_isect_2_other,
-                           plane_isect_pt_1,
-                           plane_isect_pt_2) == 0) {
+    if (!isect_line_line_v3(plane_isect_1,
+                            plane_isect_1_other,
+                            plane_isect_2,
+                            plane_isect_2_other,
+                            plane_isect_pt_1,
+                            plane_isect_pt_2)) {
       return false;
     }
 
     float cam_plane_no[3];
     float plane_isect_delta[3];
-    float plane_isect_delta_len;
 
-    float shift_fac = BKE_camera_sensor_size(
-                          params->sensor_fit, params->sensor_x, params->sensor_y) /
-                      params->lens;
+    const float shift_fac = BKE_camera_sensor_size(
+                                params->sensor_fit, params->sensor_x, params->sensor_y) /
+                            params->lens;
 
     /* we want (0, 0, -1) transformed by camera_rotmat, this is a quicker shortcut. */
     negate_v3_v3(cam_plane_no, data->camera_rotmat[2]);
 
     sub_v3_v3v3(plane_isect_delta, plane_isect_pt_2, plane_isect_pt_1);
-    plane_isect_delta_len = len_v3(plane_isect_delta);
+    const float plane_isect_delta_len = len_v3(plane_isect_delta);
 
     if (dot_v3v3(plane_isect_delta, cam_plane_no) > 0.0f) {
       copy_v3_v3(r_co, plane_isect_pt_1);
@@ -755,6 +769,11 @@ static bool camera_frame_fit_calc_from_data(CameraParams *params,
   return true;
 }
 
+#undef Y_MIN
+#undef Y_MAX
+#undef Z_MIN
+#undef Z_MAX
+
 bool BKE_camera_view_frame_fit_to_scene(Depsgraph *depsgraph,
                                         const Scene *scene,
                                         Object *camera_ob,
diff --git a/source/blender/blenkernel/intern/cdderivedmesh.c b/source/blender/blenkernel/intern/cdderivedmesh.c
index 93286751f92..0261b2d7674 100644
--- a/source/blender/blenkernel/intern/cdderivedmesh.c
+++ b/source/blender/blenkernel/intern/cdderivedmesh.c
@@ -244,43 +244,3 @@ DerivedMesh *CDDM_from_mesh(Mesh *mesh)
 {
   return cdDM_from_mesh_ex(mesh, CD_REFERENCE, &CD_MASK_MESH);
 }
-
-DerivedMesh *CDDM_copy(DerivedMesh *source)
-{
-  CDDerivedMesh *cddm = cdDM_create("CDDM_copy cddm");
-  DerivedMesh *dm = &cddm->dm;
-  int numVerts = source->numVertData;
-  int numEdges = source->numEdgeData;
-  int numTessFaces = 0;
-  int numLoops = source->numLoopData;
-  int numPolys = source->numPolyData;
-
-  /* NOTE: Don't copy tessellation faces if not requested explicitly. */
-
-  /* ensure these are created if they are made on demand */
-  source->getVertDataArray(source, CD_ORIGINDEX);
-  source->getEdgeDataArray(source, CD_ORIGINDEX);
-  source->getPolyDataArray(source, CD_ORIGINDEX);
-
-  /* this initializes dm, and copies all non mvert/medge/mface layers */
-  DM_from_template(dm, source, DM_TYPE_CDDM, numVerts, numEdges, numTessFaces, numLoops, numPolys);
-  dm->deformedOnly = source->deformedOnly;
-  dm->cd_flag = source->cd_flag;
-
-  CustomData_copy_data(&source->vertData, &dm->vertData, 0, 0, numVerts);
-  CustomData_copy_data(&source->edgeData, &dm->edgeData, 0, 0, numEdges);
-
-  /* now add mvert/medge/mface layers */
-  cddm->mvert = source->dupVertArray(source);
-  cddm->medge = source->dupEdgeArray(source);
-
-  CustomData_add_layer(&dm->vertData, CD_MVERT, CD_ASSIGN, cddm->mvert, numVerts);
-  CustomData_add_layer(&dm->edgeData, CD_MEDGE, CD_ASSIGN, cddm->medge, numEdges);
-
-  DM_DupPolys(source, dm);
-
-  cddm->mloop = CustomData_get_layer(&dm->loopData, CD_MLOOP);
-  cddm->mpoly = CustomData_get_layer(&dm->polyData, CD_MPOLY);
-
-  return dm;
-}
diff --git a/source/blender/blenkernel/intern/cloth.c b/source/blender/blenkernel/intern/cloth.c
index 8622174231c..f3bda8b1c99 100644
--- a/source/blender/blenkernel/intern/cloth.c
+++ b/source/blender/blenkernel/intern/cloth.c
@@ -97,7 +97,7 @@ static BVHTree *bvhtree_build_from_cloth(ClothModifierData *clmd, float epsilon)
     }
   }
   else {
-    MEdge *edges = cloth->edges;
+    const MEdge *edges = cloth->edges;
 
     for (int i = 0; i < cloth->primitive_num; i++) {
       float co[2][3];
@@ -177,7 +177,7 @@ void bvhtree_update_from_cloth(ClothModifierData *clmd, bool moving, bool self)
   }
   else {
     if (verts) {
-      MEdge *edges = cloth->edges;
+      const MEdge *edges = cloth->edges;
 
       for (i = 0; i < cloth->primitive_num; i++) {
         float co[2][3];
@@ -258,7 +258,7 @@ static int do_step_cloth(
 
   cloth = clmd->clothObject;
   verts = cloth->verts;
-  mvert = result->mvert;
+  mvert = BKE_mesh_verts_for_write(result);
   vert_mass_changed = verts->mass != clmd->sim_parms->mass;
 
   /* force any pinned verts to their constrained location. */
@@ -713,7 +713,6 @@ static bool cloth_from_object(
     Object *ob, ClothModifierData *clmd, Mesh *mesh, float UNUSED(framenr), int first)
 {
   int i = 0;
-  MVert *mvert = NULL;
   ClothVertex *verts = NULL;
   const float(*shapekey_rest)[3] = NULL;
   const float tnull[3] = {0, 0, 0};
@@ -755,7 +754,7 @@ static bool cloth_from_object(
     shapekey_rest = CustomData_get_layer(&mesh->vdata, CD_CLOTH_ORCO);
   }
 
-  mvert = mesh->mvert;
+  MVert *mvert = BKE_mesh_verts_for_write(mesh);
 
   verts = clmd->clothObject->verts;
 
@@ -824,7 +823,7 @@ static bool cloth_from_object(
 
 static void cloth_from_mesh(ClothModifierData *clmd, const Object *ob, Mesh *mesh)
 {
-  const MLoop *mloop = mesh->mloop;
+  const MLoop *mloop = BKE_mesh_loops(mesh);
   const MLoopTri *looptri = BKE_mesh_runtime_looptri_ensure(mesh);
   const unsigned int mvert_num = mesh->totvert;
   const unsigned int looptri_num = mesh->runtime.looptris.len;
@@ -859,7 +858,7 @@ static void cloth_from_mesh(ClothModifierData *clmd, const Object *ob, Mesh *mes
   }
   BKE_mesh_runtime_verttri_from_looptri(clmd->clothObject->tri, mloop, looptri, looptri_num);
 
-  clmd->clothObject->edges = mesh->medge;
+  clmd->clothObject->edges = BKE_mesh_edges(mesh);
 
   /* Free the springs since they can't be correct if the vertices
    * changed.
@@ -1150,7 +1149,7 @@ static void cloth_update_springs(ClothModifierData *clmd)
 static void cloth_update_verts(Object *ob, ClothModifierData *clmd, Mesh *mesh)
 {
   unsigned int i = 0;
-  MVert *mvert = mesh->mvert;
+  const MVert *mvert = BKE_mesh_verts(mesh);
   ClothVertex *verts = clmd->clothObject->verts;
 
   /* vertex count is already ensured to match */
@@ -1165,7 +1164,7 @@ static Mesh *cloth_make_rest_mesh(ClothModifierData *clmd, Mesh *mesh)
 {
   Mesh *new_mesh = BKE_mesh_copy_for_eval(mesh, false);
   ClothVertex *verts = clmd->clothObject->verts;
-  MVert *mvert = new_mesh->mvert;
+  MVert *mvert = BKE_mesh_verts_for_write(mesh);
 
   /* vertex count is already ensured to match */
   for (unsigned i = 0; i < mesh->totvert; i++, verts++) {
@@ -1459,9 +1458,9 @@ static bool cloth_build_springs(ClothModifierData *clmd, Mesh *mesh)
   unsigned int numedges = (unsigned int)mesh->totedge;
   unsigned int numpolys = (unsigned int)mesh->totpoly;
   float shrink_factor;
-  const MEdge *medge = mesh->medge;
-  const MPoly *mpoly = mesh->mpoly;
-  const MLoop *mloop = mesh->mloop;
+  const MEdge *medge = BKE_mesh_edges(mesh);
+  const MPoly *mpoly = BKE_mesh_polys(mesh);
+  const MLoop *mloop = BKE_mesh_loops(mesh);
   int index2 = 0; /* our second vertex index */
   LinkNodePair *edgelist = NULL;
   EdgeSet *edgeset = NULL;
diff --git a/source/blender/blenkernel/intern/collection.c b/source/blender/blenkernel/intern/collection.c
index b71bcef229a..98b1e3d0039 100644
--- a/source/blender/blenkernel/intern/collection.c
+++ b/source/blender/blenkernel/intern/collection.c
@@ -7,6 +7,8 @@
 /* Allow using deprecated functionality for .blend file I/O. */
 #define DNA_DEPRECATED_ALLOW
 
+#include "CLG_log.h"
+
 #include 
 
 #include "BLI_blenlib.h"
@@ -46,6 +48,8 @@
 
 #include "BLO_read_write.h"
 
+static CLG_LogRef LOG = {"bke.collection"};
+
 /* -------------------------------------------------------------------- */
 /** \name Prototypes
  * \{ */
@@ -143,6 +147,9 @@ static void collection_foreach_id(ID *id, LibraryForeachIDData *data)
 {
   Collection *collection = (Collection *)id;
 
+  BKE_LIB_FOREACHID_PROCESS_ID(
+      data, collection->owner_id, IDWALK_CB_LOOPBACK | IDWALK_CB_NEVER_SELF);
+
   LISTBASE_FOREACH (CollectionObject *, cob, &collection->gobject) {
     BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, cob->ob, IDWALK_CB_USER);
   }
@@ -162,24 +169,20 @@ static void collection_foreach_id(ID *id, LibraryForeachIDData *data)
   }
 }
 
-static ID *collection_owner_get(Main *bmain, ID *id)
+static ID **collection_owner_pointer_get(ID *id)
 {
   if ((id->flag & LIB_EMBEDDED_DATA) == 0) {
-    return id;
+    return NULL;
   }
   BLI_assert((id->tag & LIB_TAG_NO_MAIN) == 0);
 
   Collection *master_collection = (Collection *)id;
   BLI_assert((master_collection->flag & COLLECTION_IS_MASTER) != 0);
+  BLI_assert(master_collection->owner_id != NULL);
+  BLI_assert(GS(master_collection->owner_id->name) == ID_SCE);
+  BLI_assert(((Scene *)master_collection->owner_id)->master_collection == master_collection);
 
-  LISTBASE_FOREACH (Scene *, scene, &bmain->scenes) {
-    if (scene->master_collection == master_collection) {
-      return &scene->id;
-    }
-  }
-
-  BLI_assert_msg(0, "Embedded collection with no owner. Critical Main inconsistency.");
-  return NULL;
+  return &master_collection->owner_id;
 }
 
 void BKE_collection_blend_write_nolib(BlendWriter *writer, Collection *collection)
@@ -228,8 +231,35 @@ void BKE_collection_compat_blend_read_data(BlendDataReader *reader, SceneCollect
 }
 #endif
 
-void BKE_collection_blend_read_data(BlendDataReader *reader, Collection *collection)
-{
+void BKE_collection_blend_read_data(BlendDataReader *reader, Collection *collection, ID *owner_id)
+{
+  /* Special case for this pointer, do not rely on regular `lib_link` process here. Avoids needs
+   * for do_versioning, and ensures coherence of data in any case.
+   *
+   * NOTE: Old versions are very often 'broken' here, just fix it silently in these cases.
+   */
+  if (BLO_read_fileversion_get(reader) > 300) {
+    BLI_assert((collection->id.flag & LIB_EMBEDDED_DATA) != 0 || owner_id == NULL);
+  }
+  BLI_assert(owner_id == NULL || owner_id->lib == collection->id.lib);
+  if (owner_id != NULL && (collection->id.flag & LIB_EMBEDDED_DATA) == 0) {
+    /* This is unfortunate, but currently a lot of existing files (including startup ones) have
+     * missing `LIB_EMBEDDED_DATA` flag.
+     *
+     * NOTE: Using do_version is not a solution here, since this code will be called before any
+     * do_version takes place. Keeping it here also ensures future (or unknown existing) similar
+     * bugs won't go easily unnoticed. */
+    if (BLO_read_fileversion_get(reader) > 300) {
+      CLOG_WARN(&LOG,
+                "Fixing root node tree '%s' owned by '%s' missing EMBEDDED tag, please consider "
+                "re-saving your (startup) file",
+                collection->id.name,
+                owner_id->name);
+    }
+    collection->id.flag |= LIB_EMBEDDED_DATA;
+  }
+  collection->owner_id = owner_id;
+
   BLO_read_list(reader, &collection->gobject);
   BLO_read_list(reader, &collection->children);
 
@@ -260,7 +290,7 @@ void BKE_collection_blend_read_data(BlendDataReader *reader, Collection *collect
 static void collection_blend_read_data(BlendDataReader *reader, ID *id)
 {
   Collection *collection = (Collection *)id;
-  BKE_collection_blend_read_data(reader, collection);
+  BKE_collection_blend_read_data(reader, collection, NULL);
 }
 
 static void lib_link_collection_data(BlendLibReader *reader, Library *lib, Collection *collection)
@@ -370,7 +400,7 @@ IDTypeInfo IDType_ID_GR = {
     .foreach_id = collection_foreach_id,
     .foreach_cache = NULL,
     .foreach_path = NULL,
-    .owner_get = collection_owner_get,
+    .owner_pointer_get = collection_owner_pointer_get,
 
     .blend_write = collection_blend_write,
     .blend_read_data = collection_blend_read_data,
@@ -461,8 +491,8 @@ void BKE_collection_add_from_collection(Main *bmain,
       is_instantiated = true;
     }
     else if (!is_instantiated && collection_find_child(collection, collection_dst)) {
-      /* If given collection_dst is already instantiated in scene, even if its 'model' src one is
-       * not, do not add it to master scene collection. */
+      /* If given collection_dst is already instantiated in scene, even if its 'model'
+       * collection_src one is not, do not add it to master scene collection. */
       is_instantiated = true;
     }
   }
@@ -710,10 +740,11 @@ void BKE_collection_new_name_get(Collection *collection_parent, char *rname)
   char *name;
 
   if (!collection_parent) {
-    name = BLI_strdup("Collection");
+    name = BLI_strdup(DATA_("Collection"));
   }
   else if (collection_parent->flag & COLLECTION_IS_MASTER) {
-    name = BLI_sprintfN("Collection %d", BLI_listbase_count(&collection_parent->children) + 1);
+    name = BLI_sprintfN(DATA_("Collection %d"),
+                        BLI_listbase_count(&collection_parent->children) + 1);
   }
   else {
     const int number = BLI_listbase_count(&collection_parent->children) + 1;
@@ -828,13 +859,15 @@ void BKE_collection_object_cache_free(Collection *collection)
   collection_object_cache_free(collection);
 }
 
-Base *BKE_collection_or_layer_objects(const ViewLayer *view_layer, Collection *collection)
+Base *BKE_collection_or_layer_objects(const Scene *scene,
+                                      ViewLayer *view_layer,
+                                      Collection *collection)
 {
   if (collection) {
     return BKE_collection_object_cache_get(collection).first;
   }
-
-  return FIRSTBASE(view_layer);
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  return BKE_view_layer_object_bases_get(view_layer)->first;
 }
 
 /** \} */
@@ -843,14 +876,18 @@ Base *BKE_collection_or_layer_objects(const ViewLayer *view_layer, Collection *c
 /** \name Scene Master Collection
  * \{ */
 
-Collection *BKE_collection_master_add()
+Collection *BKE_collection_master_add(Scene *scene)
 {
+  BLI_assert(scene != NULL && scene->master_collection == NULL);
+
   /* Not an actual datablock, but owned by scene. */
   Collection *master_collection = BKE_libblock_alloc(
       NULL, ID_GR, BKE_SCENE_COLLECTION_NAME, LIB_ID_CREATE_NO_MAIN);
   master_collection->id.flag |= LIB_EMBEDDED_DATA;
+  master_collection->owner_id = &scene->id;
   master_collection->flag |= COLLECTION_IS_MASTER;
   master_collection->color_tag = COLLECTION_COLOR_NONE;
+
   return master_collection;
 }
 
@@ -1714,7 +1751,10 @@ Collection *BKE_collection_from_index(Scene *scene, const int index)
   return collection_from_index_recursive(master_collection, index, &index_current);
 }
 
-static bool collection_objects_select(ViewLayer *view_layer, Collection *collection, bool deselect)
+static bool collection_objects_select(const Scene *scene,
+                                      ViewLayer *view_layer,
+                                      Collection *collection,
+                                      bool deselect)
 {
   bool changed = false;
 
@@ -1722,6 +1762,7 @@ static bool collection_objects_select(ViewLayer *view_layer, Collection *collect
     return false;
   }
 
+  BKE_view_layer_synced_ensure(scene, view_layer);
   LISTBASE_FOREACH (CollectionObject *, cob, &collection->gobject) {
     Base *base = BKE_view_layer_base_find(view_layer, cob->ob);
 
@@ -1742,7 +1783,7 @@ static bool collection_objects_select(ViewLayer *view_layer, Collection *collect
   }
 
   LISTBASE_FOREACH (CollectionChild *, child, &collection->children) {
-    if (collection_objects_select(view_layer, collection, deselect)) {
+    if (collection_objects_select(scene, view_layer, collection, deselect)) {
       changed = true;
     }
   }
@@ -1750,16 +1791,19 @@ static bool collection_objects_select(ViewLayer *view_layer, Collection *collect
   return changed;
 }
 
-bool BKE_collection_objects_select(ViewLayer *view_layer, Collection *collection, bool deselect)
+bool BKE_collection_objects_select(const Scene *scene,
+                                   ViewLayer *view_layer,
+                                   Collection *collection,
+                                   bool deselect)
 {
   LayerCollection *layer_collection = BKE_layer_collection_first_from_scene_collection(view_layer,
                                                                                        collection);
 
   if (layer_collection != NULL) {
-    return BKE_layer_collection_objects_select(view_layer, layer_collection, deselect);
+    return BKE_layer_collection_objects_select(scene, view_layer, layer_collection, deselect);
   }
 
-  return collection_objects_select(view_layer, collection, deselect);
+  return collection_objects_select(scene, view_layer, collection, deselect);
 }
 
 /** \} */
diff --git a/source/blender/blenkernel/intern/collision.c b/source/blender/blenkernel/intern/collision.c
index ae99f0d17df..0bacd657981 100644
--- a/source/blender/blenkernel/intern/collision.c
+++ b/source/blender/blenkernel/intern/collision.c
@@ -1248,8 +1248,9 @@ ListBase *BKE_collision_relations_create(Depsgraph *depsgraph,
                                          Collection *collection,
                                          unsigned int modifier_type)
 {
+  const Scene *scene = DEG_get_input_scene(depsgraph);
   ViewLayer *view_layer = DEG_get_input_view_layer(depsgraph);
-  Base *base = BKE_collection_or_layer_objects(view_layer, collection);
+  Base *base = BKE_collection_or_layer_objects(scene, view_layer, collection);
   const bool for_render = (DEG_get_mode(depsgraph) == DAG_EVAL_RENDER);
   const int base_flag = (for_render) ? BASE_ENABLED_RENDER : BASE_ENABLED_VIEWPORT;
 
diff --git a/source/blender/blenkernel/intern/colorband.c b/source/blender/blenkernel/intern/colorband.c
index b2f817b7821..5145f1cbbc0 100644
--- a/source/blender/blenkernel/intern/colorband.c
+++ b/source/blender/blenkernel/intern/colorband.c
@@ -144,7 +144,7 @@ static float color_sample_remove_cost(const struct ColorResampleElem *c)
   return area;
 }
 
-/* TODO(campbell): create BLI_math_filter? */
+/* TODO(@campbellbarton): create `BLI_math_filter` ? */
 static float filter_gauss(float x)
 {
   const float gaussfac = 1.6f;
diff --git a/source/blender/blenkernel/intern/compute_contexts.cc b/source/blender/blenkernel/intern/compute_contexts.cc
new file mode 100644
index 00000000000..026706d363e
--- /dev/null
+++ b/source/blender/blenkernel/intern/compute_contexts.cc
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "BKE_compute_contexts.hh"
+
+namespace blender::bke {
+
+ModifierComputeContext::ModifierComputeContext(const ComputeContext *parent,
+                                               std::string modifier_name)
+    : ComputeContext(s_static_type, parent), modifier_name_(std::move(modifier_name))
+{
+  hash_.mix_in(s_static_type, strlen(s_static_type));
+  hash_.mix_in(modifier_name_.data(), modifier_name_.size());
+}
+
+void ModifierComputeContext::print_current_in_line(std::ostream &stream) const
+{
+  stream << "Modifier: " << modifier_name_;
+}
+
+NodeGroupComputeContext::NodeGroupComputeContext(const ComputeContext *parent,
+                                                 std::string node_name)
+    : ComputeContext(s_static_type, parent), node_name_(std::move(node_name))
+{
+  hash_.mix_in(s_static_type, strlen(s_static_type));
+  hash_.mix_in(node_name_.data(), node_name_.size());
+}
+
+StringRefNull NodeGroupComputeContext::node_name() const
+{
+  return node_name_;
+}
+
+void NodeGroupComputeContext::print_current_in_line(std::ostream &stream) const
+{
+  stream << "Node: " << node_name_;
+}
+
+}  // namespace blender::bke
diff --git a/source/blender/blenkernel/intern/constraint.c b/source/blender/blenkernel/intern/constraint.c
index 8400d610a32..cd381e15635 100644
--- a/source/blender/blenkernel/intern/constraint.c
+++ b/source/blender/blenkernel/intern/constraint.c
@@ -528,9 +528,27 @@ static void contarget_get_mesh_mat(Object *ob, const char *substring, float mat[
   float vec[3] = {0.0f, 0.0f, 0.0f};
   float normal[3] = {0.0f, 0.0f, 0.0f};
   float weightsum = 0.0f;
-  if (me_eval) {
+  if (em) {
+    if (CustomData_has_layer(&em->bm->vdata, CD_MDEFORMVERT)) {
+      BMVert *v;
+      BMIter iter;
+
+      BM_ITER_MESH (v, &iter, em->bm, BM_VERTS_OF_MESH) {
+        MDeformVert *dv = CustomData_bmesh_get(&em->bm->vdata, v->head.data, CD_MDEFORMVERT);
+        MDeformWeight *dw = BKE_defvert_find_index(dv, defgroup);
+
+        if (dw && dw->weight > 0.0f) {
+          madd_v3_v3fl(vec, v->co, dw->weight);
+          madd_v3_v3fl(normal, v->no, dw->weight);
+          weightsum += dw->weight;
+        }
+      }
+    }
+  }
+  else if (me_eval) {
     const float(*vert_normals)[3] = BKE_mesh_vertex_normals_ensure(me_eval);
     const MDeformVert *dvert = CustomData_get_layer(&me_eval->vdata, CD_MDEFORMVERT);
+    const MVert *verts = BKE_mesh_verts(me_eval);
     int numVerts = me_eval->totvert;
 
     /* check that dvert is a valid pointers (just in case) */
@@ -539,7 +557,7 @@ static void contarget_get_mesh_mat(Object *ob, const char *substring, float mat[
       /* get the average of all verts with that are in the vertex-group */
       for (int i = 0; i < numVerts; i++) {
         const MDeformVert *dv = &dvert[i];
-        const MVert *mv = &me_eval->mvert[i];
+        const MVert *mv = &verts[i];
         const MDeformWeight *dw = BKE_defvert_find_index(dv, defgroup);
 
         if (dw && dw->weight > 0.0f) {
@@ -550,23 +568,6 @@ static void contarget_get_mesh_mat(Object *ob, const char *substring, float mat[
       }
     }
   }
-  else if (em) {
-    if (CustomData_has_layer(&em->bm->vdata, CD_MDEFORMVERT)) {
-      BMVert *v;
-      BMIter iter;
-
-      BM_ITER_MESH (v, &iter, em->bm, BM_VERTS_OF_MESH) {
-        MDeformVert *dv = CustomData_bmesh_get(&em->bm->vdata, v->head.data, CD_MDEFORMVERT);
-        MDeformWeight *dw = BKE_defvert_find_index(dv, defgroup);
-
-        if (dw && dw->weight > 0.0f) {
-          madd_v3_v3fl(vec, v->co, dw->weight);
-          madd_v3_v3fl(normal, v->no, dw->weight);
-          weightsum += dw->weight;
-        }
-      }
-    }
-  }
   else {
     /* No valid edit or evaluated mesh, just abort. */
     return;
@@ -1111,7 +1112,7 @@ static void childof_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *tar
 static bConstraintTypeInfo CTI_CHILDOF = {
     CONSTRAINT_TYPE_CHILDOF,    /* type */
     sizeof(bChildOfConstraint), /* size */
-    "Child Of",                 /* name */
+    N_("Child Of"),             /* name */
     "bChildOfConstraint",       /* struct name */
     NULL,                       /* free data */
     childof_id_looper,          /* id looper */
@@ -1282,9 +1283,8 @@ static void trackto_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *tar
     cob->matrix[2][1] = 0;
     cob->matrix[2][2] = size[2];
 
-    /* targetmat[2] instead of ownermat[2] is passed to vectomat
-     * for backwards compatibility it seems... (Aligorith)
-     */
+    /* NOTE(@joshualung): `targetmat[2]` instead of `ownermat[2]` is passed to #vectomat
+     * for backwards compatibility it seems. */
     sub_v3_v3v3(vec, cob->matrix[3], ct->matrix[3]);
     vectomat(
         vec, ct->matrix[2], (short)data->reserved1, (short)data->reserved2, data->flags, totmat);
@@ -1296,7 +1296,7 @@ static void trackto_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *tar
 static bConstraintTypeInfo CTI_TRACKTO = {
     CONSTRAINT_TYPE_TRACKTO,    /* type */
     sizeof(bTrackToConstraint), /* size */
-    "Track To",                 /* name */
+    N_("Track To"),             /* name */
     "bTrackToConstraint",       /* struct name */
     NULL,                       /* free data */
     trackto_id_looper,          /* id looper */
@@ -1402,7 +1402,7 @@ static void kinematic_get_tarmat(struct Depsgraph *UNUSED(depsgraph),
 static bConstraintTypeInfo CTI_KINEMATIC = {
     CONSTRAINT_TYPE_KINEMATIC,    /* type */
     sizeof(bKinematicConstraint), /* size */
-    "IK",                         /* name */
+    N_("IK"),                     /* name */
     "bKinematicConstraint",       /* struct name */
     NULL,                         /* free data */
     kinematic_id_looper,          /* id looper */
@@ -1559,7 +1559,7 @@ static void followpath_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *
 
     /* un-apply scaling caused by path */
     if ((data->followflag & FOLLOWPATH_RADIUS) == 0) {
-      /* XXX(campbell): Assume that scale correction means that radius
+      /* XXX(@campbellbarton): Assume that scale correction means that radius
        * will have some scale error in it. */
       float obsize[3];
 
@@ -1580,7 +1580,7 @@ static void followpath_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *
 static bConstraintTypeInfo CTI_FOLLOWPATH = {
     CONSTRAINT_TYPE_FOLLOWPATH,    /* type */
     sizeof(bFollowPathConstraint), /* size */
-    "Follow Path",                 /* name */
+    N_("Follow Path"),             /* name */
     "bFollowPathConstraint",       /* struct name */
     NULL,                          /* free data */
     followpath_id_looper,          /* id looper */
@@ -1633,7 +1633,7 @@ static void loclimit_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *UN
 static bConstraintTypeInfo CTI_LOCLIMIT = {
     CONSTRAINT_TYPE_LOCLIMIT,    /* type */
     sizeof(bLocLimitConstraint), /* size */
-    "Limit Location",            /* name */
+    N_("Limit Location"),        /* name */
     "bLocLimitConstraint",       /* struct name */
     NULL,                        /* free data */
     NULL,                        /* id looper */
@@ -1714,7 +1714,7 @@ static void rotlimit_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *UN
 static bConstraintTypeInfo CTI_ROTLIMIT = {
     CONSTRAINT_TYPE_ROTLIMIT,    /* type */
     sizeof(bRotLimitConstraint), /* size */
-    "Limit Rotation",            /* name */
+    N_("Limit Rotation"),        /* name */
     "bRotLimitConstraint",       /* struct name */
     NULL,                        /* free data */
     NULL,                        /* id looper */
@@ -1781,7 +1781,7 @@ static void sizelimit_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *U
 static bConstraintTypeInfo CTI_SIZELIMIT = {
     CONSTRAINT_TYPE_SIZELIMIT,    /* type */
     sizeof(bSizeLimitConstraint), /* size */
-    "Limit Scale",                /* name */
+    N_("Limit Scale"),            /* name */
     "bSizeLimitConstraint",       /* struct name */
     NULL,                         /* free data */
     NULL,                         /* id looper */
@@ -1878,7 +1878,7 @@ static void loclike_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *tar
 static bConstraintTypeInfo CTI_LOCLIKE = {
     CONSTRAINT_TYPE_LOCLIKE,       /* type */
     sizeof(bLocateLikeConstraint), /* size */
-    "Copy Location",               /* name */
+    N_("Copy Location"),           /* name */
     "bLocateLikeConstraint",       /* struct name */
     NULL,                          /* free data */
     loclike_id_looper,             /* id looper */
@@ -2055,7 +2055,7 @@ static void rotlike_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *tar
 static bConstraintTypeInfo CTI_ROTLIKE = {
     CONSTRAINT_TYPE_ROTLIKE,       /* type */
     sizeof(bRotateLikeConstraint), /* size */
-    "Copy Rotation",               /* name */
+    N_("Copy Rotation"),           /* name */
     "bRotateLikeConstraint",       /* struct name */
     NULL,                          /* free data */
     rotlike_id_looper,             /* id looper */
@@ -2185,7 +2185,7 @@ static void sizelike_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *ta
 static bConstraintTypeInfo CTI_SIZELIKE = {
     CONSTRAINT_TYPE_SIZELIKE,    /* type */
     sizeof(bSizeLikeConstraint), /* size */
-    "Copy Scale",                /* name */
+    N_("Copy Scale"),            /* name */
     "bSizeLikeConstraint",       /* struct name */
     NULL,                        /* free data */
     sizelike_id_looper,          /* id looper */
@@ -2291,7 +2291,7 @@ static void translike_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *t
 static bConstraintTypeInfo CTI_TRANSLIKE = {
     CONSTRAINT_TYPE_TRANSLIKE,     /* type */
     sizeof(bTransLikeConstraint),  /* size */
-    "Copy Transforms",             /* name */
+    N_("Copy Transforms"),         /* name */
     "bTransLikeConstraint",        /* struct name */
     NULL,                          /* free data */
     translike_id_looper,           /* id looper */
@@ -2360,7 +2360,7 @@ static void samevolume_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *
 static bConstraintTypeInfo CTI_SAMEVOL = {
     CONSTRAINT_TYPE_SAMEVOL,       /* type */
     sizeof(bSameVolumeConstraint), /* size */
-    "Maintain Volume",             /* name */
+    N_("Maintain Volume"),         /* name */
     "bSameVolumeConstraint",       /* struct name */
     NULL,                          /* free data */
     NULL,                          /* id looper */
@@ -2492,7 +2492,7 @@ static void pycon_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *targe
 static bConstraintTypeInfo CTI_PYTHON = {
     CONSTRAINT_TYPE_PYTHON,    /* type */
     sizeof(bPythonConstraint), /* size */
-    "Script",                  /* name */
+    N_("Script"),              /* name */
     "bPythonConstraint",       /* struct name */
     pycon_free,                /* free data */
     pycon_id_looper,           /* id looper */
@@ -2739,7 +2739,7 @@ static void armdef_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *targ
 static bConstraintTypeInfo CTI_ARMATURE = {
     CONSTRAINT_TYPE_ARMATURE,    /* type */
     sizeof(bArmatureConstraint), /* size */
-    "Armature",                  /* name */
+    N_("Armature"),              /* name */
     "bArmatureConstraint",       /* struct name */
     armdef_free,                 /* free data */
     armdef_id_looper,            /* id looper */
@@ -2955,7 +2955,7 @@ static void actcon_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *targ
 static bConstraintTypeInfo CTI_ACTION = {
     CONSTRAINT_TYPE_ACTION,    /* type */
     sizeof(bActionConstraint), /* size */
-    "Action",                  /* name */
+    N_("Action"),              /* name */
     "bActionConstraint",       /* struct name */
     NULL,                      /* free data */
     actcon_id_looper,          /* id looper */
@@ -3271,7 +3271,7 @@ static void locktrack_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *t
 static bConstraintTypeInfo CTI_LOCKTRACK = {
     CONSTRAINT_TYPE_LOCKTRACK,    /* type */
     sizeof(bLockTrackConstraint), /* size */
-    "Locked Track",               /* name */
+    N_("Locked Track"),           /* name */
     "bLockTrackConstraint",       /* struct name */
     NULL,                         /* free data */
     locktrack_id_looper,          /* id looper */
@@ -3414,7 +3414,7 @@ static void distlimit_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *t
 static bConstraintTypeInfo CTI_DISTLIMIT = {
     CONSTRAINT_TYPE_DISTLIMIT,    /* type */
     sizeof(bDistLimitConstraint), /* size */
-    "Limit Distance",             /* name */
+    N_("Limit Distance"),         /* name */
     "bDistLimitConstraint",       /* struct name */
     NULL,                         /* free data */
     distlimit_id_looper,          /* id looper */
@@ -3622,7 +3622,7 @@ static void stretchto_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *t
 static bConstraintTypeInfo CTI_STRETCHTO = {
     CONSTRAINT_TYPE_STRETCHTO,    /* type */
     sizeof(bStretchToConstraint), /* size */
-    "Stretch To",                 /* name */
+    N_("Stretch To"),             /* name */
     "bStretchToConstraint",       /* struct name */
     NULL,                         /* free data */
     stretchto_id_looper,          /* id looper */
@@ -3753,7 +3753,7 @@ static void minmax_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *targ
 static bConstraintTypeInfo CTI_MINMAX = {
     CONSTRAINT_TYPE_MINMAX,    /* type */
     sizeof(bMinMaxConstraint), /* size */
-    "Floor",                   /* name */
+    N_("Floor"),               /* name */
     "bMinMaxConstraint",       /* struct name */
     NULL,                      /* free data */
     minmax_id_looper,          /* id looper */
@@ -3939,7 +3939,7 @@ static void clampto_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *tar
 static bConstraintTypeInfo CTI_CLAMPTO = {
     CONSTRAINT_TYPE_CLAMPTO,    /* type */
     sizeof(bClampToConstraint), /* size */
-    "Clamp To",                 /* name */
+    N_("Clamp To"),             /* name */
     "bClampToConstraint",       /* struct name */
     NULL,                       /* free data */
     clampto_id_looper,          /* id looper */
@@ -4148,7 +4148,7 @@ static void transform_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *t
 static bConstraintTypeInfo CTI_TRANSFORM = {
     CONSTRAINT_TYPE_TRANSFORM,    /* type */
     sizeof(bTransformConstraint), /* size */
-    "Transformation",             /* name */
+    N_("Transformation"),         /* name */
     "bTransformConstraint",       /* struct name */
     NULL,                         /* free data */
     transform_id_looper,          /* id looper */
@@ -4379,7 +4379,7 @@ static void shrinkwrap_evaluate(bConstraint *UNUSED(con), bConstraintOb *cob, Li
 static bConstraintTypeInfo CTI_SHRINKWRAP = {
     CONSTRAINT_TYPE_SHRINKWRAP,    /* type */
     sizeof(bShrinkwrapConstraint), /* size */
-    "Shrinkwrap",                  /* name */
+    N_("Shrinkwrap"),              /* name */
     "bShrinkwrapConstraint",       /* struct name */
     NULL,                          /* free data */
     shrinkwrap_id_looper,          /* id looper */
@@ -4544,7 +4544,7 @@ static void damptrack_do_transform(float matrix[4][4], const float tarvec_in[3],
 static bConstraintTypeInfo CTI_DAMPTRACK = {
     CONSTRAINT_TYPE_DAMPTRACK,    /* type */
     sizeof(bDampTrackConstraint), /* size */
-    "Damped Track",               /* name */
+    N_("Damped Track"),           /* name */
     "bDampTrackConstraint",       /* struct name */
     NULL,                         /* free data */
     damptrack_id_looper,          /* id looper */
@@ -4639,7 +4639,7 @@ static void splineik_get_tarmat(struct Depsgraph *UNUSED(depsgraph),
 static bConstraintTypeInfo CTI_SPLINEIK = {
     CONSTRAINT_TYPE_SPLINEIK,    /* type */
     sizeof(bSplineIKConstraint), /* size */
-    "Spline IK",                 /* name */
+    N_("Spline IK"),             /* name */
     "bSplineIKConstraint",       /* struct name */
     splineik_free,               /* free data */
     splineik_id_looper,          /* id looper */
@@ -4763,7 +4763,7 @@ static void pivotcon_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *ta
 static bConstraintTypeInfo CTI_PIVOT = {
     CONSTRAINT_TYPE_PIVOT,    /* type */
     sizeof(bPivotConstraint), /* size */
-    "Pivot",                  /* name */
+    N_("Pivot"),              /* name */
     "bPivotConstraint",       /* struct name */
     NULL,                     /* free data */
     pivotcon_id_looper,       /* id looper */
@@ -5184,7 +5184,7 @@ static void followtrack_evaluate(bConstraint *con, bConstraintOb *cob, ListBase
 static bConstraintTypeInfo CTI_FOLLOWTRACK = {
     CONSTRAINT_TYPE_FOLLOWTRACK,    /* type */
     sizeof(bFollowTrackConstraint), /* size */
-    "Follow Track",                 /* name */
+    N_("Follow Track"),             /* name */
     "bFollowTrackConstraint",       /* struct name */
     NULL,                           /* free data */
     followtrack_id_looper,          /* id looper */
@@ -5242,7 +5242,7 @@ static void camerasolver_evaluate(bConstraint *con, bConstraintOb *cob, ListBase
 static bConstraintTypeInfo CTI_CAMERASOLVER = {
     CONSTRAINT_TYPE_CAMERASOLVER,    /* type */
     sizeof(bCameraSolverConstraint), /* size */
-    "Camera Solver",                 /* name */
+    N_("Camera Solver"),             /* name */
     "bCameraSolverConstraint",       /* struct name */
     NULL,                            /* free data */
     camerasolver_id_looper,          /* id looper */
@@ -5330,7 +5330,7 @@ static void objectsolver_evaluate(bConstraint *con, bConstraintOb *cob, ListBase
 static bConstraintTypeInfo CTI_OBJECTSOLVER = {
     CONSTRAINT_TYPE_OBJECTSOLVER,    /* type */
     sizeof(bObjectSolverConstraint), /* size */
-    "Object Solver",                 /* name */
+    N_("Object Solver"),             /* name */
     "bObjectSolverConstraint",       /* struct name */
     NULL,                            /* free data */
     objectsolver_id_looper,          /* id looper */
@@ -5427,7 +5427,7 @@ static void transformcache_new_data(void *cdata)
 static bConstraintTypeInfo CTI_TRANSFORM_CACHE = {
     CONSTRAINT_TYPE_TRANSFORM_CACHE,   /* type */
     sizeof(bTransformCacheConstraint), /* size */
-    "Transform Cache",                 /* name */
+    N_("Transform Cache"),             /* name */
     "bTransformCacheConstraint",       /* struct name */
     transformcache_free,               /* free data */
     transformcache_id_looper,          /* id looper */
@@ -5844,9 +5844,12 @@ static bConstraint *add_new_constraint(Object *ob,
   return con;
 }
 
-bool BKE_constraint_target_uses_bbone(struct bConstraint *con,
-                                      struct bConstraintTarget *UNUSED(ct))
+bool BKE_constraint_target_uses_bbone(struct bConstraint *con, struct bConstraintTarget *ct)
 {
+  if (ct->flag & CONSTRAINT_TAR_CUSTOM_SPACE) {
+    return false;
+  }
+
   return (con->flag & CONSTRAINT_BBONE_SHAPE) || (con->type == CONSTRAINT_TYPE_ARMATURE);
 }
 
@@ -5928,12 +5931,12 @@ static void constraint_copy_data_ex(bConstraint *dst,
       cti->copy_data(dst, src);
     }
 
-    /* Fix usercounts for all referenced data that need it. */
+    /* Fix user-counts for all referenced data that need it. */
     if ((flag & LIB_ID_CREATE_NO_USER_REFCOUNT) == 0) {
       con_invoke_id_looper(cti, dst, con_fix_copied_refs_cb, NULL);
     }
 
-    /* for proxies we don't want to make extern */
+    /* For proxies we don't want to make external. */
     if (do_extern) {
       /* go over used ID-links for this constraint to ensure that they are valid for proxies */
       con_invoke_id_looper(cti, dst, con_extern_cb, NULL);
@@ -6259,6 +6262,9 @@ void BKE_constraint_target_matrix_get(struct Depsgraph *depsgraph,
       }
     }
 
+    /* Initialize the custom space for use in calculating the matrices. */
+    BKE_constraint_custom_object_space_init(cob, con);
+
     /* get targets - we only need the first one though (and there should only be one) */
     cti->get_constraint_targets(con, &targets);
 
diff --git a/source/blender/blenkernel/intern/context.c b/source/blender/blenkernel/intern/context.c
index 1f1a49ca030..ceb84d213c3 100644
--- a/source/blender/blenkernel/intern/context.c
+++ b/source/blender/blenkernel/intern/context.c
@@ -440,6 +440,7 @@ static int ctx_data_base_collection_get(const bContext *C, const char *member, L
 
   Scene *scene = CTX_data_scene(C);
   ViewLayer *view_layer = CTX_data_view_layer(C);
+  BKE_view_layer_synced_ensure(scene, view_layer);
 
   bool ok = false;
 
@@ -1362,8 +1363,9 @@ struct Base *CTX_data_active_base(const bContext *C)
   if (ob == NULL) {
     return NULL;
   }
-
+  const Scene *scene = CTX_data_scene(C);
   ViewLayer *view_layer = CTX_data_view_layer(C);
+  BKE_view_layer_synced_ensure(scene, view_layer);
   return BKE_view_layer_base_find(view_layer, ob);
 }
 
diff --git a/source/blender/blenkernel/intern/crazyspace.c b/source/blender/blenkernel/intern/crazyspace.c
deleted file mode 100644
index 14e862c2377..00000000000
--- a/source/blender/blenkernel/intern/crazyspace.c
+++ /dev/null
@@ -1,584 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later
- * Copyright 2005 Blender Foundation. All rights reserved. */
-
-/** \file
- * \ingroup bke
- */
-
-#include "MEM_guardedalloc.h"
-
-#include "DNA_mesh_types.h"
-#include "DNA_meshdata_types.h"
-#include "DNA_modifier_types.h"
-#include "DNA_object_types.h"
-#include "DNA_scene_types.h"
-
-#include "BLI_bitmap.h"
-#include "BLI_linklist.h"
-#include "BLI_utildefines.h"
-
-#include "BKE_DerivedMesh.h"
-#include "BKE_crazyspace.h"
-#include "BKE_editmesh.h"
-#include "BKE_lib_id.h"
-#include "BKE_mesh.h"
-#include "BKE_mesh_wrapper.h"
-#include "BKE_modifier.h"
-#include "BKE_multires.h"
-#include "BKE_report.h"
-
-#include "DEG_depsgraph_query.h"
-
-BLI_INLINE void tan_calc_quat_v3(float r_quat[4],
-                                 const float co_1[3],
-                                 const float co_2[3],
-                                 const float co_3[3])
-{
-  float vec_u[3], vec_v[3];
-  float nor[3];
-
-  sub_v3_v3v3(vec_u, co_1, co_2);
-  sub_v3_v3v3(vec_v, co_1, co_3);
-
-  cross_v3_v3v3(nor, vec_u, vec_v);
-
-  if (normalize_v3(nor) > FLT_EPSILON) {
-    const float zero_vec[3] = {0.0f};
-    tri_to_quat_ex(r_quat, zero_vec, vec_u, vec_v, nor);
-  }
-  else {
-    unit_qt(r_quat);
-  }
-}
-
-static void set_crazy_vertex_quat(float r_quat[4],
-                                  const float co_1[3],
-                                  const float co_2[3],
-                                  const float co_3[3],
-                                  const float vd_1[3],
-                                  const float vd_2[3],
-                                  const float vd_3[3])
-{
-  float q1[4], q2[4];
-
-  tan_calc_quat_v3(q1, co_1, co_2, co_3);
-  tan_calc_quat_v3(q2, vd_1, vd_2, vd_3);
-
-  sub_qt_qtqt(r_quat, q2, q1);
-}
-
-static bool modifiers_disable_subsurf_temporary(struct Scene *scene, Object *ob)
-{
-  bool disabled = false;
-  int cageIndex = BKE_modifiers_get_cage_index(scene, ob, NULL, 1);
-
-  ModifierData *md = ob->modifiers.first;
-  for (int i = 0; md && i <= cageIndex; i++, md = md->next) {
-    if (md->type == eModifierType_Subsurf) {
-      md->mode ^= eModifierMode_DisableTemporary;
-      disabled = true;
-    }
-  }
-
-  return disabled;
-}
-
-float (*BKE_crazyspace_get_mapped_editverts(struct Depsgraph *depsgraph, Object *obedit))[3]
-{
-  Scene *scene = DEG_get_input_scene(depsgraph);
-  Scene *scene_eval = DEG_get_evaluated_scene(depsgraph);
-  Object *obedit_eval = DEG_get_evaluated_object(depsgraph, obedit);
-  Mesh *mesh_eval = obedit_eval->data;
-  BMEditMesh *editmesh_eval = mesh_eval->edit_mesh;
-
-  /* disable subsurf temporal, get mapped cos, and enable it */
-  if (modifiers_disable_subsurf_temporary(scene_eval, obedit_eval)) {
-    /* need to make new derivemesh */
-    makeDerivedMesh(depsgraph, scene_eval, obedit_eval, &CD_MASK_BAREMESH);
-  }
-
-  /* now get the cage */
-  Mesh *mesh_eval_cage = editbmesh_get_eval_cage_from_orig(
-      depsgraph, scene, obedit, &CD_MASK_BAREMESH);
-
-  const int nverts = editmesh_eval->bm->totvert;
-  float(*vertexcos)[3] = MEM_mallocN(sizeof(*vertexcos) * nverts, "vertexcos map");
-  mesh_get_mapped_verts_coords(mesh_eval_cage, vertexcos, nverts);
-
-  /* set back the flag, no new cage needs to be built, transform does it */
-  modifiers_disable_subsurf_temporary(scene_eval, obedit_eval);
-
-  return vertexcos;
-}
-
-void BKE_crazyspace_set_quats_editmesh(BMEditMesh *em,
-                                       float (*origcos)[3],
-                                       float (*mappedcos)[3],
-                                       float (*quats)[4],
-                                       const bool use_select)
-{
-  BMFace *f;
-  BMIter iter;
-  int index;
-
-  {
-    BMVert *v;
-    BM_ITER_MESH_INDEX (v, &iter, em->bm, BM_VERTS_OF_MESH, index) {
-      BM_elem_flag_disable(v, BM_ELEM_TAG);
-      BM_elem_index_set(v, index); /* set_inline */
-    }
-    em->bm->elem_index_dirty &= ~BM_VERT;
-  }
-
-  BM_ITER_MESH (f, &iter, em->bm, BM_FACES_OF_MESH) {
-    BMLoop *l_iter, *l_first;
-
-    l_iter = l_first = BM_FACE_FIRST_LOOP(f);
-    do {
-      if (BM_elem_flag_test(l_iter->v, BM_ELEM_HIDDEN) ||
-          BM_elem_flag_test(l_iter->v, BM_ELEM_TAG) ||
-          (use_select && !BM_elem_flag_test(l_iter->v, BM_ELEM_SELECT))) {
-        continue;
-      }
-
-      if (!BM_elem_flag_test(l_iter->v, BM_ELEM_TAG)) {
-        const float *co_prev, *co_curr, *co_next; /* orig */
-        const float *vd_prev, *vd_curr, *vd_next; /* deform */
-
-        const int i_prev = BM_elem_index_get(l_iter->prev->v);
-        const int i_curr = BM_elem_index_get(l_iter->v);
-        const int i_next = BM_elem_index_get(l_iter->next->v);
-
-        /* retrieve mapped coordinates */
-        vd_prev = mappedcos[i_prev];
-        vd_curr = mappedcos[i_curr];
-        vd_next = mappedcos[i_next];
-
-        if (origcos) {
-          co_prev = origcos[i_prev];
-          co_curr = origcos[i_curr];
-          co_next = origcos[i_next];
-        }
-        else {
-          co_prev = l_iter->prev->v->co;
-          co_curr = l_iter->v->co;
-          co_next = l_iter->next->v->co;
-        }
-
-        set_crazy_vertex_quat(quats[i_curr], co_curr, co_next, co_prev, vd_curr, vd_next, vd_prev);
-
-        BM_elem_flag_enable(l_iter->v, BM_ELEM_TAG);
-      }
-    } while ((l_iter = l_iter->next) != l_first);
-  }
-}
-
-void BKE_crazyspace_set_quats_mesh(Mesh *me,
-                                   float (*origcos)[3],
-                                   float (*mappedcos)[3],
-                                   float (*quats)[4])
-{
-  BLI_bitmap *vert_tag = BLI_BITMAP_NEW(me->totvert, __func__);
-
-  /* first store two sets of tangent vectors in vertices, we derive it just from the face-edges */
-  MVert *mvert = me->mvert;
-  MPoly *mp = me->mpoly;
-  MLoop *mloop = me->mloop;
-
-  for (int i = 0; i < me->totpoly; i++, mp++) {
-    MLoop *ml_next = &mloop[mp->loopstart];
-    MLoop *ml_curr = &ml_next[mp->totloop - 1];
-    MLoop *ml_prev = &ml_next[mp->totloop - 2];
-
-    for (int j = 0; j < mp->totloop; j++) {
-      if (!BLI_BITMAP_TEST(vert_tag, ml_curr->v)) {
-        const float *co_prev, *co_curr, *co_next; /* orig */
-        const float *vd_prev, *vd_curr, *vd_next; /* deform */
-
-        /* retrieve mapped coordinates */
-        vd_prev = mappedcos[ml_prev->v];
-        vd_curr = mappedcos[ml_curr->v];
-        vd_next = mappedcos[ml_next->v];
-
-        if (origcos) {
-          co_prev = origcos[ml_prev->v];
-          co_curr = origcos[ml_curr->v];
-          co_next = origcos[ml_next->v];
-        }
-        else {
-          co_prev = mvert[ml_prev->v].co;
-          co_curr = mvert[ml_curr->v].co;
-          co_next = mvert[ml_next->v].co;
-        }
-
-        set_crazy_vertex_quat(
-            quats[ml_curr->v], co_curr, co_next, co_prev, vd_curr, vd_next, vd_prev);
-
-        BLI_BITMAP_ENABLE(vert_tag, ml_curr->v);
-      }
-
-      ml_prev = ml_curr;
-      ml_curr = ml_next;
-      ml_next++;
-    }
-  }
-
-  MEM_freeN(vert_tag);
-}
-
-int BKE_crazyspace_get_first_deform_matrices_editbmesh(struct Depsgraph *depsgraph,
-                                                       Scene *scene,
-                                                       Object *ob,
-                                                       BMEditMesh *em,
-                                                       float (**deformmats)[3][3],
-                                                       float (**deformcos)[3])
-{
-  ModifierData *md;
-  Mesh *me_input = ob->data;
-  Mesh *me = NULL;
-  int i, a, modifiers_left_num = 0, verts_num = 0;
-  int cageIndex = BKE_modifiers_get_cage_index(scene, ob, NULL, 1);
-  float(*defmats)[3][3] = NULL, (*deformedVerts)[3] = NULL;
-  VirtualModifierData virtualModifierData;
-  ModifierEvalContext mectx = {depsgraph, ob, 0};
-
-  BKE_modifiers_clear_errors(ob);
-
-  md = BKE_modifiers_get_virtual_modifierlist(ob, &virtualModifierData);
-
-  /* compute the deformation matrices and coordinates for the first
-   * modifiers with on cage editing that are enabled and support computing
-   * deform matrices */
-  for (i = 0; md && i <= cageIndex; i++, md = md->next) {
-    const ModifierTypeInfo *mti = BKE_modifier_get_info(md->type);
-
-    if (!editbmesh_modifier_is_enabled(scene, ob, md, me != NULL)) {
-      continue;
-    }
-
-    if (mti->type == eModifierTypeType_OnlyDeform && mti->deformMatricesEM) {
-      if (!defmats) {
-        const int required_mode = eModifierMode_Realtime | eModifierMode_Editmode;
-        CustomData_MeshMasks cd_mask_extra = CD_MASK_BAREMESH;
-        CDMaskLink *datamasks = BKE_modifier_calc_data_masks(
-            scene, ob, md, &cd_mask_extra, required_mode, NULL, NULL);
-        cd_mask_extra = datamasks->mask;
-        BLI_linklist_free((LinkNode *)datamasks, NULL);
-
-        me = BKE_mesh_wrapper_from_editmesh_with_coords(em, &cd_mask_extra, NULL, me_input);
-        deformedVerts = editbmesh_vert_coords_alloc(em, &verts_num);
-        defmats = MEM_mallocN(sizeof(*defmats) * verts_num, "defmats");
-
-        for (a = 0; a < verts_num; a++) {
-          unit_m3(defmats[a]);
-        }
-      }
-      mti->deformMatricesEM(md, &mectx, em, me, deformedVerts, defmats, verts_num);
-    }
-    else {
-      break;
-    }
-  }
-
-  for (; md && i <= cageIndex; md = md->next, i++) {
-    if (editbmesh_modifier_is_enabled(scene, ob, md, me != NULL) &&
-        BKE_modifier_is_correctable_deformed(md)) {
-      modifiers_left_num++;
-    }
-  }
-
-  if (me) {
-    BKE_id_free(NULL, me);
-  }
-
-  *deformmats = defmats;
-  *deformcos = deformedVerts;
-
-  return modifiers_left_num;
-}
-
-/**
- * Crazy-space evaluation needs to have an object which has all the fields
- * evaluated, but the mesh data being at undeformed state. This way it can
- * re-apply modifiers and also have proper pointers to key data blocks.
- *
- * Similar to #BKE_object_eval_reset(), but does not modify the actual evaluated object.
- */
-static void crazyspace_init_object_for_eval(struct Depsgraph *depsgraph,
-                                            Object *object,
-                                            Object *object_crazy)
-{
-  Object *object_eval = DEG_get_evaluated_object(depsgraph, object);
-  *object_crazy = *object_eval;
-  if (object_crazy->runtime.data_orig != NULL) {
-    object_crazy->data = object_crazy->runtime.data_orig;
-  }
-}
-
-static void crazyspace_init_verts_and_matrices(const Mesh *mesh,
-                                               float (**deformmats)[3][3],
-                                               float (**deformcos)[3])
-{
-  int verts_num;
-  *deformcos = BKE_mesh_vert_coords_alloc(mesh, &verts_num);
-  *deformmats = MEM_callocN(sizeof(**deformmats) * verts_num, "defmats");
-  for (int a = 0; a < verts_num; a++) {
-    unit_m3((*deformmats)[a]);
-  }
-  BLI_assert(verts_num == mesh->totvert);
-}
-
-static bool crazyspace_modifier_supports_deform_matrices(ModifierData *md)
-{
-  if (ELEM(md->type, eModifierType_Subsurf, eModifierType_Multires)) {
-    return true;
-  }
-  const ModifierTypeInfo *mti = BKE_modifier_get_info(md->type);
-  return (mti->type == eModifierTypeType_OnlyDeform);
-}
-
-static bool crazyspace_modifier_supports_deform(ModifierData *md)
-{
-  const ModifierTypeInfo *mti = BKE_modifier_get_info(md->type);
-  return (mti->type == eModifierTypeType_OnlyDeform);
-}
-
-int BKE_sculpt_get_first_deform_matrices(struct Depsgraph *depsgraph,
-                                         Scene *scene,
-                                         Object *object,
-                                         float (**deformmats)[3][3],
-                                         float (**deformcos)[3])
-{
-  ModifierData *md;
-  Mesh *me_eval = NULL;
-  float(*defmats)[3][3] = NULL, (*deformedVerts)[3] = NULL;
-  int modifiers_left_num = 0;
-  VirtualModifierData virtualModifierData;
-  Object object_eval;
-  crazyspace_init_object_for_eval(depsgraph, object, &object_eval);
-  MultiresModifierData *mmd = get_multires_modifier(scene, &object_eval, 0);
-  const bool is_sculpt_mode = (object->mode & OB_MODE_SCULPT) != 0;
-  const bool has_multires = mmd != NULL && mmd->sculptlvl > 0;
-  const ModifierEvalContext mectx = {depsgraph, &object_eval, 0};
-
-  if (is_sculpt_mode && has_multires) {
-    *deformmats = NULL;
-    *deformcos = NULL;
-    return modifiers_left_num;
-  }
-
-  md = BKE_modifiers_get_virtual_modifierlist(&object_eval, &virtualModifierData);
-
-  for (; md; md = md->next) {
-    if (!BKE_modifier_is_enabled(scene, md, eModifierMode_Realtime)) {
-      continue;
-    }
-
-    if (crazyspace_modifier_supports_deform_matrices(md)) {
-      const ModifierTypeInfo *mti = BKE_modifier_get_info(md->type);
-      if (defmats == NULL) {
-        /* NOTE: Evaluated object is re-set to its original un-deformed state. */
-        Mesh *me = object_eval.data;
-        me_eval = BKE_mesh_copy_for_eval(me, true);
-        crazyspace_init_verts_and_matrices(me_eval, &defmats, &deformedVerts);
-      }
-
-      if (mti->deformMatrices) {
-        mti->deformMatrices(md, &mectx, me_eval, deformedVerts, defmats, me_eval->totvert);
-      }
-      else {
-        /* More complex handling will continue in BKE_crazyspace_build_sculpt.
-         * Exiting the loop on a non-deform modifier causes issues - T71213. */
-        BLI_assert(crazyspace_modifier_supports_deform(md));
-        break;
-      }
-    }
-  }
-
-  for (; md; md = md->next) {
-    if (!BKE_modifier_is_enabled(scene, md, eModifierMode_Realtime)) {
-      continue;
-    }
-
-    if (crazyspace_modifier_supports_deform(md)) {
-      modifiers_left_num++;
-    }
-  }
-
-  if (me_eval != NULL) {
-    BKE_id_free(NULL, me_eval);
-  }
-
-  *deformmats = defmats;
-  *deformcos = deformedVerts;
-
-  return modifiers_left_num;
-}
-
-void BKE_crazyspace_build_sculpt(struct Depsgraph *depsgraph,
-                                 Scene *scene,
-                                 Object *object,
-                                 float (**deformmats)[3][3],
-                                 float (**deformcos)[3])
-{
-  int totleft = BKE_sculpt_get_first_deform_matrices(
-      depsgraph, scene, object, deformmats, deformcos);
-
-  if (totleft) {
-    /* There are deformation modifier which doesn't support deformation matrices calculation.
-     * Need additional crazy-space correction. */
-
-    Mesh *mesh = (Mesh *)object->data;
-    Mesh *mesh_eval = NULL;
-
-    if (*deformcos == NULL) {
-      crazyspace_init_verts_and_matrices(mesh, deformmats, deformcos);
-    }
-
-    float(*deformedVerts)[3] = *deformcos;
-    float(*origVerts)[3] = MEM_dupallocN(deformedVerts);
-    float(*quats)[4];
-    int i, deformed = 0;
-    VirtualModifierData virtualModifierData;
-    Object object_eval;
-    crazyspace_init_object_for_eval(depsgraph, object, &object_eval);
-    ModifierData *md = BKE_modifiers_get_virtual_modifierlist(&object_eval, &virtualModifierData);
-    const ModifierEvalContext mectx = {depsgraph, &object_eval, 0};
-
-    for (; md; md = md->next) {
-      if (!BKE_modifier_is_enabled(scene, md, eModifierMode_Realtime)) {
-        continue;
-      }
-
-      if (crazyspace_modifier_supports_deform(md)) {
-        const ModifierTypeInfo *mti = BKE_modifier_get_info(md->type);
-
-        /* skip leading modifiers which have been already
-         * handled in sculpt_get_first_deform_matrices */
-        if (mti->deformMatrices && !deformed) {
-          continue;
-        }
-
-        if (mesh_eval == NULL) {
-          mesh_eval = BKE_mesh_copy_for_eval(mesh, true);
-        }
-
-        mti->deformVerts(md, &mectx, mesh_eval, deformedVerts, mesh_eval->totvert);
-        deformed = 1;
-      }
-    }
-
-    quats = MEM_mallocN(mesh->totvert * sizeof(*quats), "crazy quats");
-
-    BKE_crazyspace_set_quats_mesh(mesh, origVerts, deformedVerts, quats);
-
-    for (i = 0; i < mesh->totvert; i++) {
-      float qmat[3][3], tmat[3][3];
-
-      quat_to_mat3(qmat, quats[i]);
-      mul_m3_m3m3(tmat, qmat, (*deformmats)[i]);
-      copy_m3_m3((*deformmats)[i], tmat);
-    }
-
-    MEM_freeN(origVerts);
-    MEM_freeN(quats);
-
-    if (mesh_eval != NULL) {
-      BKE_id_free(NULL, mesh_eval);
-    }
-  }
-
-  if (*deformmats == NULL) {
-    int a, verts_num;
-    Mesh *mesh = (Mesh *)object->data;
-
-    *deformcos = BKE_mesh_vert_coords_alloc(mesh, &verts_num);
-    *deformmats = MEM_callocN(sizeof(*(*deformmats)) * verts_num, "defmats");
-
-    for (a = 0; a < verts_num; a++) {
-      unit_m3((*deformmats)[a]);
-    }
-  }
-}
-
-/* -------------------------------------------------------------------- */
-/** \name Crazyspace API
- * \{ */
-
-void BKE_crazyspace_api_eval(Depsgraph *depsgraph,
-                             Scene *scene,
-                             Object *object,
-                             struct ReportList *reports)
-{
-  if (object->runtime.crazyspace_deform_imats != NULL ||
-      object->runtime.crazyspace_deform_cos != NULL) {
-    return;
-  }
-
-  if (object->type != OB_MESH) {
-    BKE_report(reports,
-               RPT_ERROR,
-               "Crazyspace transformation is only available for Mesh type of objects");
-    return;
-  }
-
-  const Mesh *mesh = (const Mesh *)object->data;
-  object->runtime.crazyspace_verts_num = mesh->totvert;
-  BKE_crazyspace_build_sculpt(depsgraph,
-                              scene,
-                              object,
-                              &object->runtime.crazyspace_deform_imats,
-                              &object->runtime.crazyspace_deform_cos);
-}
-
-void BKE_crazyspace_api_displacement_to_deformed(struct Object *object,
-                                                 struct ReportList *reports,
-                                                 int vertex_index,
-                                                 float displacement[3],
-                                                 float r_displacement_deformed[3])
-{
-  if (vertex_index < 0 || vertex_index >= object->runtime.crazyspace_verts_num) {
-    BKE_reportf(reports,
-                RPT_ERROR,
-                "Invalid vertex index %d (expected to be within 0 to %d range)",
-                vertex_index,
-                object->runtime.crazyspace_verts_num);
-    return;
-  }
-
-  mul_v3_m3v3(r_displacement_deformed,
-              object->runtime.crazyspace_deform_imats[vertex_index],
-              displacement);
-}
-
-void BKE_crazyspace_api_displacement_to_original(struct Object *object,
-                                                 struct ReportList *reports,
-                                                 int vertex_index,
-                                                 float displacement_deformed[3],
-                                                 float r_displacement[3])
-{
-  if (vertex_index < 0 || vertex_index >= object->runtime.crazyspace_verts_num) {
-    BKE_reportf(reports,
-                RPT_ERROR,
-                "Invalid vertex index %d (expected to be within 0 to %d range))",
-                vertex_index,
-                object->runtime.crazyspace_verts_num);
-    return;
-  }
-
-  float mat[3][3];
-  if (!invert_m3_m3(mat, object->runtime.crazyspace_deform_imats[vertex_index])) {
-    copy_v3_v3(r_displacement, displacement_deformed);
-    return;
-  }
-
-  mul_v3_m3v3(r_displacement, mat, displacement_deformed);
-}
-
-void BKE_crazyspace_api_eval_clear(Object *object)
-{
-  MEM_SAFE_FREE(object->runtime.crazyspace_deform_imats);
-  MEM_SAFE_FREE(object->runtime.crazyspace_deform_cos);
-}
-
-/** \} */
diff --git a/source/blender/blenkernel/intern/crazyspace.cc b/source/blender/blenkernel/intern/crazyspace.cc
new file mode 100644
index 00000000000..190e2d3bb7e
--- /dev/null
+++ b/source/blender/blenkernel/intern/crazyspace.cc
@@ -0,0 +1,655 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright 2005 Blender Foundation. All rights reserved. */
+
+/** \file
+ * \ingroup bke
+ */
+
+#include "MEM_guardedalloc.h"
+
+#include "DNA_mesh_types.h"
+#include "DNA_meshdata_types.h"
+#include "DNA_modifier_types.h"
+#include "DNA_object_types.h"
+#include "DNA_scene_types.h"
+
+#include "BLI_bitmap.h"
+#include "BLI_linklist.h"
+#include "BLI_utildefines.h"
+
+#include "BKE_DerivedMesh.h"
+#include "BKE_crazyspace.h"
+#include "BKE_crazyspace.hh"
+#include "BKE_curves.hh"
+#include "BKE_editmesh.h"
+#include "BKE_geometry_set.hh"
+#include "BKE_lib_id.h"
+#include "BKE_mesh.h"
+#include "BKE_mesh_wrapper.h"
+#include "BKE_modifier.h"
+#include "BKE_multires.h"
+#include "BKE_report.h"
+
+#include "DEG_depsgraph_query.h"
+
+BLI_INLINE void tan_calc_quat_v3(float r_quat[4],
+                                 const float co_1[3],
+                                 const float co_2[3],
+                                 const float co_3[3])
+{
+  float vec_u[3], vec_v[3];
+  float nor[3];
+
+  sub_v3_v3v3(vec_u, co_1, co_2);
+  sub_v3_v3v3(vec_v, co_1, co_3);
+
+  cross_v3_v3v3(nor, vec_u, vec_v);
+
+  if (normalize_v3(nor) > FLT_EPSILON) {
+    const float zero_vec[3] = {0.0f};
+    tri_to_quat_ex(r_quat, zero_vec, vec_u, vec_v, nor);
+  }
+  else {
+    unit_qt(r_quat);
+  }
+}
+
+static void set_crazy_vertex_quat(float r_quat[4],
+                                  const float co_1[3],
+                                  const float co_2[3],
+                                  const float co_3[3],
+                                  const float vd_1[3],
+                                  const float vd_2[3],
+                                  const float vd_3[3])
+{
+  float q1[4], q2[4];
+
+  tan_calc_quat_v3(q1, co_1, co_2, co_3);
+  tan_calc_quat_v3(q2, vd_1, vd_2, vd_3);
+
+  sub_qt_qtqt(r_quat, q2, q1);
+}
+
+static bool modifiers_disable_subsurf_temporary(struct Scene *scene, Object *ob)
+{
+  bool disabled = false;
+  int cageIndex = BKE_modifiers_get_cage_index(scene, ob, nullptr, true);
+
+  ModifierData *md = static_cast(ob->modifiers.first);
+  for (int i = 0; md && i <= cageIndex; i++, md = md->next) {
+    if (md->type == eModifierType_Subsurf) {
+      md->mode ^= eModifierMode_DisableTemporary;
+      disabled = true;
+    }
+  }
+
+  return disabled;
+}
+
+float (*BKE_crazyspace_get_mapped_editverts(struct Depsgraph *depsgraph, Object *obedit))[3]
+{
+  Scene *scene = DEG_get_input_scene(depsgraph);
+  Scene *scene_eval = DEG_get_evaluated_scene(depsgraph);
+  Object *obedit_eval = DEG_get_evaluated_object(depsgraph, obedit);
+  Mesh *mesh_eval = static_cast(obedit_eval->data);
+  BMEditMesh *editmesh_eval = mesh_eval->edit_mesh;
+
+  /* disable subsurf temporal, get mapped cos, and enable it */
+  if (modifiers_disable_subsurf_temporary(scene_eval, obedit_eval)) {
+    /* Need to make new derived-mesh. */
+    makeDerivedMesh(depsgraph, scene_eval, obedit_eval, &CD_MASK_BAREMESH);
+  }
+
+  /* now get the cage */
+  Mesh *mesh_eval_cage = editbmesh_get_eval_cage_from_orig(
+      depsgraph, scene, obedit, &CD_MASK_BAREMESH);
+
+  const int nverts = editmesh_eval->bm->totvert;
+  float(*vertexcos)[3] = static_cast(
+      MEM_mallocN(sizeof(*vertexcos) * nverts, "vertexcos map"));
+  mesh_get_mapped_verts_coords(mesh_eval_cage, vertexcos, nverts);
+
+  /* set back the flag, no new cage needs to be built, transform does it */
+  modifiers_disable_subsurf_temporary(scene_eval, obedit_eval);
+
+  return vertexcos;
+}
+
+void BKE_crazyspace_set_quats_editmesh(BMEditMesh *em,
+                                       float (*origcos)[3],
+                                       float (*mappedcos)[3],
+                                       float (*quats)[4],
+                                       const bool use_select)
+{
+  BMFace *f;
+  BMIter iter;
+  int index;
+
+  {
+    BMVert *v;
+    BM_ITER_MESH_INDEX (v, &iter, em->bm, BM_VERTS_OF_MESH, index) {
+      BM_elem_flag_disable(v, BM_ELEM_TAG);
+      BM_elem_index_set(v, index); /* set_inline */
+    }
+    em->bm->elem_index_dirty &= ~BM_VERT;
+  }
+
+  BM_ITER_MESH (f, &iter, em->bm, BM_FACES_OF_MESH) {
+    BMLoop *l_iter, *l_first;
+
+    l_iter = l_first = BM_FACE_FIRST_LOOP(f);
+    do {
+      if (BM_elem_flag_test(l_iter->v, BM_ELEM_HIDDEN) ||
+          BM_elem_flag_test(l_iter->v, BM_ELEM_TAG) ||
+          (use_select && !BM_elem_flag_test(l_iter->v, BM_ELEM_SELECT))) {
+        continue;
+      }
+
+      if (!BM_elem_flag_test(l_iter->v, BM_ELEM_TAG)) {
+        const float *co_prev, *co_curr, *co_next; /* orig */
+        const float *vd_prev, *vd_curr, *vd_next; /* deform */
+
+        const int i_prev = BM_elem_index_get(l_iter->prev->v);
+        const int i_curr = BM_elem_index_get(l_iter->v);
+        const int i_next = BM_elem_index_get(l_iter->next->v);
+
+        /* retrieve mapped coordinates */
+        vd_prev = mappedcos[i_prev];
+        vd_curr = mappedcos[i_curr];
+        vd_next = mappedcos[i_next];
+
+        if (origcos) {
+          co_prev = origcos[i_prev];
+          co_curr = origcos[i_curr];
+          co_next = origcos[i_next];
+        }
+        else {
+          co_prev = l_iter->prev->v->co;
+          co_curr = l_iter->v->co;
+          co_next = l_iter->next->v->co;
+        }
+
+        set_crazy_vertex_quat(quats[i_curr], co_curr, co_next, co_prev, vd_curr, vd_next, vd_prev);
+
+        BM_elem_flag_enable(l_iter->v, BM_ELEM_TAG);
+      }
+    } while ((l_iter = l_iter->next) != l_first);
+  }
+}
+
+void BKE_crazyspace_set_quats_mesh(Mesh *me,
+                                   float (*origcos)[3],
+                                   float (*mappedcos)[3],
+                                   float (*quats)[4])
+{
+  using namespace blender;
+  using namespace blender::bke;
+  BLI_bitmap *vert_tag = BLI_BITMAP_NEW(me->totvert, __func__);
+
+  /* first store two sets of tangent vectors in vertices, we derive it just from the face-edges */
+  const Span verts = me->verts();
+  const Span polys = me->polys();
+  const Span loops = me->loops();
+
+  for (int i = 0; i < me->totpoly; i++) {
+    const MPoly *poly = &polys[i];
+    const MLoop *ml_next = &loops[poly->loopstart];
+    const MLoop *ml_curr = &ml_next[poly->totloop - 1];
+    const MLoop *ml_prev = &ml_next[poly->totloop - 2];
+
+    for (int j = 0; j < poly->totloop; j++) {
+      if (!BLI_BITMAP_TEST(vert_tag, ml_curr->v)) {
+        const float *co_prev, *co_curr, *co_next; /* orig */
+        const float *vd_prev, *vd_curr, *vd_next; /* deform */
+
+        /* retrieve mapped coordinates */
+        vd_prev = mappedcos[ml_prev->v];
+        vd_curr = mappedcos[ml_curr->v];
+        vd_next = mappedcos[ml_next->v];
+
+        if (origcos) {
+          co_prev = origcos[ml_prev->v];
+          co_curr = origcos[ml_curr->v];
+          co_next = origcos[ml_next->v];
+        }
+        else {
+          co_prev = verts[ml_prev->v].co;
+          co_curr = verts[ml_curr->v].co;
+          co_next = verts[ml_next->v].co;
+        }
+
+        set_crazy_vertex_quat(
+            quats[ml_curr->v], co_curr, co_next, co_prev, vd_curr, vd_next, vd_prev);
+
+        BLI_BITMAP_ENABLE(vert_tag, ml_curr->v);
+      }
+
+      ml_prev = ml_curr;
+      ml_curr = ml_next;
+      ml_next++;
+    }
+  }
+
+  MEM_freeN(vert_tag);
+}
+
+int BKE_crazyspace_get_first_deform_matrices_editbmesh(struct Depsgraph *depsgraph,
+                                                       Scene *scene,
+                                                       Object *ob,
+                                                       BMEditMesh *em,
+                                                       float (**deformmats)[3][3],
+                                                       float (**deformcos)[3])
+{
+  ModifierData *md;
+  Mesh *me_input = static_cast(ob->data);
+  Mesh *me = nullptr;
+  int i, a, modifiers_left_num = 0, verts_num = 0;
+  int cageIndex = BKE_modifiers_get_cage_index(scene, ob, nullptr, true);
+  float(*defmats)[3][3] = nullptr, (*deformedVerts)[3] = nullptr;
+  VirtualModifierData virtualModifierData;
+  ModifierEvalContext mectx = {depsgraph, ob, ModifierApplyFlag(0)};
+
+  BKE_modifiers_clear_errors(ob);
+
+  md = BKE_modifiers_get_virtual_modifierlist(ob, &virtualModifierData);
+
+  /* compute the deformation matrices and coordinates for the first
+   * modifiers with on cage editing that are enabled and support computing
+   * deform matrices */
+  for (i = 0; md && i <= cageIndex; i++, md = md->next) {
+    const ModifierTypeInfo *mti = BKE_modifier_get_info(static_cast(md->type));
+
+    if (!editbmesh_modifier_is_enabled(scene, ob, md, me != nullptr)) {
+      continue;
+    }
+
+    if (mti->type == eModifierTypeType_OnlyDeform && mti->deformMatricesEM) {
+      if (!defmats) {
+        const int required_mode = eModifierMode_Realtime | eModifierMode_Editmode;
+        CustomData_MeshMasks cd_mask_extra = CD_MASK_BAREMESH;
+        CDMaskLink *datamasks = BKE_modifier_calc_data_masks(
+            scene, md, &cd_mask_extra, required_mode, nullptr, nullptr);
+        cd_mask_extra = datamasks->mask;
+        BLI_linklist_free((LinkNode *)datamasks, nullptr);
+
+        me = BKE_mesh_wrapper_from_editmesh_with_coords(em, &cd_mask_extra, nullptr, me_input);
+        deformedVerts = editbmesh_vert_coords_alloc(em, &verts_num);
+        defmats = static_cast(
+            MEM_mallocN(sizeof(*defmats) * verts_num, "defmats"));
+
+        for (a = 0; a < verts_num; a++) {
+          unit_m3(defmats[a]);
+        }
+      }
+      mti->deformMatricesEM(md, &mectx, em, me, deformedVerts, defmats, verts_num);
+    }
+    else {
+      break;
+    }
+  }
+
+  for (; md && i <= cageIndex; md = md->next, i++) {
+    if (editbmesh_modifier_is_enabled(scene, ob, md, me != nullptr) &&
+        BKE_modifier_is_correctable_deformed(md)) {
+      modifiers_left_num++;
+    }
+  }
+
+  if (me) {
+    BKE_id_free(nullptr, me);
+  }
+
+  *deformmats = defmats;
+  *deformcos = deformedVerts;
+
+  return modifiers_left_num;
+}
+
+/**
+ * Crazy-space evaluation needs to have an object which has all the fields
+ * evaluated, but the mesh data being at undeformed state. This way it can
+ * re-apply modifiers and also have proper pointers to key data blocks.
+ *
+ * Similar to #BKE_object_eval_reset(), but does not modify the actual evaluated object.
+ */
+static void crazyspace_init_object_for_eval(struct Depsgraph *depsgraph,
+                                            Object *object,
+                                            Object *object_crazy)
+{
+  Object *object_eval = DEG_get_evaluated_object(depsgraph, object);
+  *object_crazy = blender::dna::shallow_copy(*object_eval);
+  if (object_crazy->runtime.data_orig != nullptr) {
+    object_crazy->data = object_crazy->runtime.data_orig;
+  }
+}
+
+static void crazyspace_init_verts_and_matrices(const Mesh *mesh,
+                                               float (**deformmats)[3][3],
+                                               float (**deformcos)[3])
+{
+  int verts_num;
+  *deformcos = BKE_mesh_vert_coords_alloc(mesh, &verts_num);
+  *deformmats = static_cast(
+      MEM_callocN(sizeof(**deformmats) * verts_num, "defmats"));
+  for (int a = 0; a < verts_num; a++) {
+    unit_m3((*deformmats)[a]);
+  }
+  BLI_assert(verts_num == mesh->totvert);
+}
+
+static bool crazyspace_modifier_supports_deform_matrices(ModifierData *md)
+{
+  if (ELEM(md->type, eModifierType_Subsurf, eModifierType_Multires)) {
+    return true;
+  }
+  const ModifierTypeInfo *mti = BKE_modifier_get_info(static_cast(md->type));
+  return (mti->type == eModifierTypeType_OnlyDeform);
+}
+
+static bool crazyspace_modifier_supports_deform(ModifierData *md)
+{
+  const ModifierTypeInfo *mti = BKE_modifier_get_info(static_cast(md->type));
+  return (mti->type == eModifierTypeType_OnlyDeform);
+}
+
+int BKE_sculpt_get_first_deform_matrices(struct Depsgraph *depsgraph,
+                                         Scene *scene,
+                                         Object *object,
+                                         float (**deformmats)[3][3],
+                                         float (**deformcos)[3])
+{
+  ModifierData *md;
+  Mesh *me_eval = nullptr;
+  float(*defmats)[3][3] = nullptr, (*deformedVerts)[3] = nullptr;
+  int modifiers_left_num = 0;
+  VirtualModifierData virtualModifierData;
+  Object object_eval;
+  crazyspace_init_object_for_eval(depsgraph, object, &object_eval);
+  MultiresModifierData *mmd = get_multires_modifier(scene, &object_eval, false);
+  const bool is_sculpt_mode = (object->mode & OB_MODE_SCULPT) != 0;
+  const bool has_multires = mmd != nullptr && mmd->sculptlvl > 0;
+  const ModifierEvalContext mectx = {depsgraph, &object_eval, ModifierApplyFlag(0)};
+
+  if (is_sculpt_mode && has_multires) {
+    *deformmats = nullptr;
+    *deformcos = nullptr;
+    return modifiers_left_num;
+  }
+
+  md = BKE_modifiers_get_virtual_modifierlist(&object_eval, &virtualModifierData);
+
+  for (; md; md = md->next) {
+    if (!BKE_modifier_is_enabled(scene, md, eModifierMode_Realtime)) {
+      continue;
+    }
+
+    if (crazyspace_modifier_supports_deform_matrices(md)) {
+      const ModifierTypeInfo *mti = BKE_modifier_get_info(static_cast(md->type));
+      if (defmats == nullptr) {
+        /* NOTE: Evaluated object is re-set to its original un-deformed state. */
+        Mesh *me = static_cast(object_eval.data);
+        me_eval = BKE_mesh_copy_for_eval(me, true);
+        crazyspace_init_verts_and_matrices(me_eval, &defmats, &deformedVerts);
+      }
+
+      if (mti->deformMatrices) {
+        mti->deformMatrices(md, &mectx, me_eval, deformedVerts, defmats, me_eval->totvert);
+      }
+      else {
+        /* More complex handling will continue in BKE_crazyspace_build_sculpt.
+         * Exiting the loop on a non-deform modifier causes issues - T71213. */
+        BLI_assert(crazyspace_modifier_supports_deform(md));
+        break;
+      }
+    }
+  }
+
+  for (; md; md = md->next) {
+    if (!BKE_modifier_is_enabled(scene, md, eModifierMode_Realtime)) {
+      continue;
+    }
+
+    if (crazyspace_modifier_supports_deform(md)) {
+      modifiers_left_num++;
+    }
+  }
+
+  if (me_eval != nullptr) {
+    BKE_id_free(nullptr, me_eval);
+  }
+
+  *deformmats = defmats;
+  *deformcos = deformedVerts;
+
+  return modifiers_left_num;
+}
+
+void BKE_crazyspace_build_sculpt(struct Depsgraph *depsgraph,
+                                 Scene *scene,
+                                 Object *object,
+                                 float (**deformmats)[3][3],
+                                 float (**deformcos)[3])
+{
+  int totleft = BKE_sculpt_get_first_deform_matrices(
+      depsgraph, scene, object, deformmats, deformcos);
+
+  if (totleft) {
+    /* There are deformation modifier which doesn't support deformation matrices calculation.
+     * Need additional crazy-space correction. */
+
+    Mesh *mesh = (Mesh *)object->data;
+    Mesh *mesh_eval = nullptr;
+
+    if (*deformcos == nullptr) {
+      crazyspace_init_verts_and_matrices(mesh, deformmats, deformcos);
+    }
+
+    float(*deformedVerts)[3] = *deformcos;
+    float(*origVerts)[3] = static_cast(MEM_dupallocN(deformedVerts));
+    float(*quats)[4];
+    int i, deformed = 0;
+    VirtualModifierData virtualModifierData;
+    Object object_eval;
+    crazyspace_init_object_for_eval(depsgraph, object, &object_eval);
+    ModifierData *md = BKE_modifiers_get_virtual_modifierlist(&object_eval, &virtualModifierData);
+    const ModifierEvalContext mectx = {depsgraph, &object_eval, ModifierApplyFlag(0)};
+
+    for (; md; md = md->next) {
+      if (!BKE_modifier_is_enabled(scene, md, eModifierMode_Realtime)) {
+        continue;
+      }
+
+      if (crazyspace_modifier_supports_deform(md)) {
+        const ModifierTypeInfo *mti = BKE_modifier_get_info(static_cast(md->type));
+
+        /* skip leading modifiers which have been already
+         * handled in sculpt_get_first_deform_matrices */
+        if (mti->deformMatrices && !deformed) {
+          continue;
+        }
+
+        if (mesh_eval == nullptr) {
+          mesh_eval = BKE_mesh_copy_for_eval(mesh, true);
+        }
+
+        mti->deformVerts(md, &mectx, mesh_eval, deformedVerts, mesh_eval->totvert);
+        deformed = 1;
+      }
+    }
+
+    quats = static_cast(MEM_mallocN(mesh->totvert * sizeof(*quats), "crazy quats"));
+
+    BKE_crazyspace_set_quats_mesh(mesh, origVerts, deformedVerts, quats);
+
+    for (i = 0; i < mesh->totvert; i++) {
+      float qmat[3][3], tmat[3][3];
+
+      quat_to_mat3(qmat, quats[i]);
+      mul_m3_m3m3(tmat, qmat, (*deformmats)[i]);
+      copy_m3_m3((*deformmats)[i], tmat);
+    }
+
+    MEM_freeN(origVerts);
+    MEM_freeN(quats);
+
+    if (mesh_eval != nullptr) {
+      BKE_id_free(nullptr, mesh_eval);
+    }
+  }
+
+  if (*deformmats == nullptr) {
+    int a, verts_num;
+    Mesh *mesh = (Mesh *)object->data;
+
+    *deformcos = BKE_mesh_vert_coords_alloc(mesh, &verts_num);
+    *deformmats = static_cast(
+        MEM_callocN(sizeof(*(*deformmats)) * verts_num, "defmats"));
+
+    for (a = 0; a < verts_num; a++) {
+      unit_m3((*deformmats)[a]);
+    }
+  }
+}
+
+/* -------------------------------------------------------------------- */
+/** \name Crazyspace API
+ * \{ */
+
+void BKE_crazyspace_api_eval(Depsgraph *depsgraph,
+                             Scene *scene,
+                             Object *object,
+                             struct ReportList *reports)
+{
+  if (object->runtime.crazyspace_deform_imats != nullptr ||
+      object->runtime.crazyspace_deform_cos != nullptr) {
+    return;
+  }
+
+  if (object->type != OB_MESH) {
+    BKE_report(reports,
+               RPT_ERROR,
+               "Crazyspace transformation is only available for Mesh type of objects");
+    return;
+  }
+
+  const Mesh *mesh = (const Mesh *)object->data;
+  object->runtime.crazyspace_verts_num = mesh->totvert;
+  BKE_crazyspace_build_sculpt(depsgraph,
+                              scene,
+                              object,
+                              &object->runtime.crazyspace_deform_imats,
+                              &object->runtime.crazyspace_deform_cos);
+}
+
+void BKE_crazyspace_api_displacement_to_deformed(struct Object *object,
+                                                 struct ReportList *reports,
+                                                 int vertex_index,
+                                                 float displacement[3],
+                                                 float r_displacement_deformed[3])
+{
+  if (vertex_index < 0 || vertex_index >= object->runtime.crazyspace_verts_num) {
+    BKE_reportf(reports,
+                RPT_ERROR,
+                "Invalid vertex index %d (expected to be within 0 to %d range)",
+                vertex_index,
+                object->runtime.crazyspace_verts_num);
+    return;
+  }
+
+  mul_v3_m3v3(r_displacement_deformed,
+              object->runtime.crazyspace_deform_imats[vertex_index],
+              displacement);
+}
+
+void BKE_crazyspace_api_displacement_to_original(struct Object *object,
+                                                 struct ReportList *reports,
+                                                 int vertex_index,
+                                                 float displacement_deformed[3],
+                                                 float r_displacement[3])
+{
+  if (vertex_index < 0 || vertex_index >= object->runtime.crazyspace_verts_num) {
+    BKE_reportf(reports,
+                RPT_ERROR,
+                "Invalid vertex index %d (expected to be within 0 to %d range))",
+                vertex_index,
+                object->runtime.crazyspace_verts_num);
+    return;
+  }
+
+  float mat[3][3];
+  if (!invert_m3_m3(mat, object->runtime.crazyspace_deform_imats[vertex_index])) {
+    copy_v3_v3(r_displacement, displacement_deformed);
+    return;
+  }
+
+  mul_v3_m3v3(r_displacement, mat, displacement_deformed);
+}
+
+void BKE_crazyspace_api_eval_clear(Object *object)
+{
+  MEM_SAFE_FREE(object->runtime.crazyspace_deform_imats);
+  MEM_SAFE_FREE(object->runtime.crazyspace_deform_cos);
+}
+
+/** \} */
+
+namespace blender::bke::crazyspace {
+
+GeometryDeformation get_evaluated_curves_deformation(const Depsgraph &depsgraph,
+                                                     const Object &ob_orig)
+{
+  BLI_assert(ob_orig.type == OB_CURVES);
+  const Curves &curves_id_orig = *static_cast(ob_orig.data);
+  const CurvesGeometry &curves_orig = CurvesGeometry::wrap(curves_id_orig.geometry);
+  const int points_num = curves_orig.points_num();
+
+  GeometryDeformation deformation;
+  /* Use the undeformed positions by default. */
+  deformation.positions = curves_orig.positions();
+
+  const Object *ob_eval = DEG_get_evaluated_object(&depsgraph, const_cast(&ob_orig));
+  if (ob_eval == nullptr) {
+    return deformation;
+  }
+  const GeometrySet *geometry_eval = ob_eval->runtime.geometry_set_eval;
+  if (geometry_eval == nullptr) {
+    return deformation;
+  }
+
+  /* If available, use deformation information generated during evaluation. */
+  const GeometryComponentEditData *edit_component_eval =
+      geometry_eval->get_component_for_read();
+  bool uses_extra_positions = false;
+  if (edit_component_eval != nullptr) {
+    const CurvesEditHints *edit_hints = edit_component_eval->curves_edit_hints_.get();
+    if (edit_hints != nullptr && &edit_hints->curves_id_orig == &curves_id_orig) {
+      if (edit_hints->positions.has_value()) {
+        BLI_assert(edit_hints->positions->size() == points_num);
+        deformation.positions = *edit_hints->positions;
+        uses_extra_positions = true;
+      }
+      if (edit_hints->deform_mats.has_value()) {
+        BLI_assert(edit_hints->deform_mats->size() == points_num);
+        deformation.deform_mats = *edit_hints->deform_mats;
+      }
+    }
+  }
+
+  /* Use the positions of the evaluated curves directly, if the number of points matches. */
+  if (!uses_extra_positions) {
+    const CurveComponent *curves_component_eval =
+        geometry_eval->get_component_for_read();
+    if (curves_component_eval != nullptr) {
+      const Curves *curves_id_eval = curves_component_eval->get_for_read();
+      if (curves_id_eval != nullptr) {
+        const CurvesGeometry &curves_eval = CurvesGeometry::wrap(curves_id_eval->geometry);
+        if (curves_eval.points_num() == points_num) {
+          deformation.positions = curves_eval.positions();
+        }
+      }
+    }
+  }
+  return deformation;
+}
+
+}  // namespace blender::bke::crazyspace
diff --git a/source/blender/blenkernel/intern/cryptomatte.cc b/source/blender/blenkernel/intern/cryptomatte.cc
index 102bda0f2b6..72204f6624e 100644
--- a/source/blender/blenkernel/intern/cryptomatte.cc
+++ b/source/blender/blenkernel/intern/cryptomatte.cc
@@ -41,7 +41,9 @@ struct CryptomatteSession {
   CryptomatteSession() = default;
   CryptomatteSession(const Main *bmain);
   CryptomatteSession(StampData *stamp_data);
+  CryptomatteSession(const ViewLayer *view_layer);
   CryptomatteSession(const Scene *scene);
+  void init(const ViewLayer *view_layer);
 
   blender::bke::cryptomatte::CryptomatteLayer &add_layer(std::string layer_name);
   std::optional operator[](float encoded_hash) const;
@@ -54,13 +56,15 @@ struct CryptomatteSession {
 CryptomatteSession::CryptomatteSession(const Main *bmain)
 {
   if (!BLI_listbase_is_empty(&bmain->objects)) {
-    blender::bke::cryptomatte::CryptomatteLayer &objects = add_layer("CryptoObject");
+    blender::bke::cryptomatte::CryptomatteLayer &objects = add_layer(
+        RE_PASSNAME_CRYPTOMATTE_OBJECT);
     LISTBASE_FOREACH (ID *, id, &bmain->objects) {
       objects.add_ID(*id);
     }
   }
   if (!BLI_listbase_is_empty(&bmain->materials)) {
-    blender::bke::cryptomatte::CryptomatteLayer &materials = add_layer("CryptoMaterial");
+    blender::bke::cryptomatte::CryptomatteLayer &materials = add_layer(
+        RE_PASSNAME_CRYPTOMATTE_MATERIAL);
     LISTBASE_FOREACH (ID *, id, &bmain->materials) {
       materials.add_ID(*id);
     }
@@ -83,24 +87,34 @@ CryptomatteSession::CryptomatteSession(StampData *stamp_data)
       false);
 }
 
+CryptomatteSession::CryptomatteSession(const ViewLayer *view_layer)
+{
+  init(view_layer);
+}
+
 CryptomatteSession::CryptomatteSession(const Scene *scene)
 {
-  LISTBASE_FOREACH (ViewLayer *, view_layer, &scene->view_layers) {
-    eViewLayerCryptomatteFlags cryptoflags = static_cast(
-        view_layer->cryptomatte_flag & VIEW_LAYER_CRYPTOMATTE_ALL);
-    if (cryptoflags == 0) {
-      cryptoflags = static_cast(VIEW_LAYER_CRYPTOMATTE_ALL);
-    }
+  LISTBASE_FOREACH (const ViewLayer *, view_layer, &scene->view_layers) {
+    init(view_layer);
+  }
+}
 
-    if (cryptoflags & VIEW_LAYER_CRYPTOMATTE_OBJECT) {
-      add_layer(blender::StringRefNull(view_layer->name) + ".CryptoObject");
-    }
-    if (cryptoflags & VIEW_LAYER_CRYPTOMATTE_ASSET) {
-      add_layer(blender::StringRefNull(view_layer->name) + ".CryptoAsset");
-    }
-    if (cryptoflags & VIEW_LAYER_CRYPTOMATTE_MATERIAL) {
-      add_layer(blender::StringRefNull(view_layer->name) + ".CryptoMaterial");
-    }
+void CryptomatteSession::init(const ViewLayer *view_layer)
+{
+  eViewLayerCryptomatteFlags cryptoflags = static_cast(
+      view_layer->cryptomatte_flag & VIEW_LAYER_CRYPTOMATTE_ALL);
+  if (cryptoflags == 0) {
+    cryptoflags = static_cast(VIEW_LAYER_CRYPTOMATTE_ALL);
+  }
+
+  if (cryptoflags & VIEW_LAYER_CRYPTOMATTE_OBJECT) {
+    add_layer(blender::StringRefNull(view_layer->name) + "." + RE_PASSNAME_CRYPTOMATTE_OBJECT);
+  }
+  if (cryptoflags & VIEW_LAYER_CRYPTOMATTE_ASSET) {
+    add_layer(blender::StringRefNull(view_layer->name) + "." + RE_PASSNAME_CRYPTOMATTE_ASSET);
+  }
+  if (cryptoflags & VIEW_LAYER_CRYPTOMATTE_MATERIAL) {
+    add_layer(blender::StringRefNull(view_layer->name) + "." + RE_PASSNAME_CRYPTOMATTE_MATERIAL);
   }
 }
 
@@ -142,6 +156,12 @@ struct CryptomatteSession *BKE_cryptomatte_init_from_scene(const struct Scene *s
   return session;
 }
 
+struct CryptomatteSession *BKE_cryptomatte_init_from_view_layer(const struct ViewLayer *view_layer)
+{
+  CryptomatteSession *session = new CryptomatteSession(view_layer);
+  return session;
+}
+
 void BKE_cryptomatte_add_layer(struct CryptomatteSession *session, const char *layer_name)
 {
   session->add_layer(layer_name);
@@ -485,11 +505,6 @@ CryptomatteHash::CryptomatteHash(uint32_t hash) : hash(hash)
 {
 }
 
-CryptomatteHash::CryptomatteHash(const char *name, const int name_len)
-{
-  hash = BLI_hash_mm3((const unsigned char *)name, name_len, 0);
-}
-
 CryptomatteHash CryptomatteHash::from_hex_encoded(blender::StringRef hex_encoded)
 {
   CryptomatteHash result(0);
@@ -504,21 +519,6 @@ std::string CryptomatteHash::hex_encoded() const
   return encoded.str();
 }
 
-float CryptomatteHash::float_encoded() const
-{
-  uint32_t mantissa = hash & ((1 << 23) - 1);
-  uint32_t exponent = (hash >> 23) & ((1 << 8) - 1);
-  exponent = MAX2(exponent, (uint32_t)1);
-  exponent = MIN2(exponent, (uint32_t)254);
-  exponent = exponent << 23;
-  uint32_t sign = (hash >> 31);
-  sign = sign << 31;
-  uint32_t float_bits = sign | exponent | mantissa;
-  float f;
-  memcpy(&f, &float_bits, sizeof(uint32_t));
-  return f;
-}
-
 std::unique_ptr CryptomatteLayer::read_from_manifest(
     blender::StringRefNull manifest)
 {
@@ -625,4 +625,9 @@ const blender::Vector &BKE_cryptomatte_layer_names_get(
   return session.layer_names;
 }
 
+CryptomatteLayer *BKE_cryptomatte_layer_get(CryptomatteSession &session, StringRef layer_name)
+{
+  return session.layers.lookup_ptr(layer_name);
+}
+
 }  // namespace blender::bke::cryptomatte
diff --git a/source/blender/blenkernel/intern/cryptomatte_test.cc b/source/blender/blenkernel/intern/cryptomatte_test.cc
index 2f15242b4a4..bb09b276645 100644
--- a/source/blender/blenkernel/intern/cryptomatte_test.cc
+++ b/source/blender/blenkernel/intern/cryptomatte_test.cc
@@ -163,7 +163,7 @@ TEST(cryptomatte, session_from_stamp_data)
  * best as possible. */
 TEST(cryptomatte, parsing_malformed_manifests)
 {
-  /* Manifest from multilayer.exr in the cryptomatte git-repository. */
+  /* Manifest from `multilayer.exr` in the cryptomatte git-repository. */
   test_cryptomatte_manifest(
       R"({"/obj/instance1:instances:0":"0d54c6cc","/obj/instance1:instances:1":"293d9340","/obj/instance1:instances:110":"ccb9e1f2","/obj/instance1:instances:111":"f8dd3a48","/obj/instance1:instances:112":"a99e07a8","/obj/instance1:instances:113":"e75599a4","/obj/instance1:instances:114":"794200f3","/obj/instance1:instances:115":"2a3a1728","/obj/instance1:instances:116":"478544a1","/obj/instance1:instances:117":"b2bd969a","/obj/instance1:instances:10":"3a0c8681","/obj/instance1:instances:11":"01e5970d","/obj/box:polygons:1":"9d416418","/obj/instance1:instances:100":"2dcd2966","/obj/instance1:instances:101":"9331cd82","/obj/instance1:instances:102":"df50fccb","/obj/instance1:instances:103":"97f8590d","/obj/instance1:instances:104":"bbcd220d","/obj/instance1:instances:105":"4ae06139","/obj/instance1:instances:106":"8873d5ea","/obj/instance1:instances:107":"39d8af8d","/obj/instance1:instances:108":"bb11bd4e","/obj/instance1:instances:109":"a32bba35"})",
       R"({"\/obj\/box:polygons:1":"9d416418","\/obj\/instance1:instances:0":"0d54c6cc","\/obj\/instance1:instances:1":"293d9340","\/obj\/instance1:instances:10":"3a0c8681","\/obj\/instance1:instances:100":"2dcd2966","\/obj\/instance1:instances:101":"9331cd82","\/obj\/instance1:instances:102":"df50fccb","\/obj\/instance1:instances:103":"97f8590d","\/obj\/instance1:instances:104":"bbcd220d","\/obj\/instance1:instances:105":"4ae06139","\/obj\/instance1:instances:106":"8873d5ea","\/obj\/instance1:instances:107":"39d8af8d","\/obj\/instance1:instances:108":"bb11bd4e","\/obj\/instance1:instances:109":"a32bba35","\/obj\/instance1:instances:11":"01e5970d","\/obj\/instance1:instances:110":"ccb9e1f2","\/obj\/instance1:instances:111":"f8dd3a48","\/obj\/instance1:instances:112":"a99e07a8","\/obj\/instance1:instances:113":"e75599a4","\/obj\/instance1:instances:114":"794200f3","\/obj\/instance1:instances:115":"2a3a1728","\/obj\/instance1:instances:116":"478544a1","\/obj\/instance1:instances:117":"b2bd969a","\/obj\/instance1:instance)");
diff --git a/source/blender/blenkernel/intern/curve.cc b/source/blender/blenkernel/intern/curve.cc
index 5125e010b81..ca390fae424 100644
--- a/source/blender/blenkernel/intern/curve.cc
+++ b/source/blender/blenkernel/intern/curve.cc
@@ -321,7 +321,7 @@ IDTypeInfo IDType_ID_CU_LEGACY = {
     /* foreach_id */ curve_foreach_id,
     /* foreach_cache */ nullptr,
     /* foreach_path */ nullptr,
-    /* owner_get */ nullptr,
+    /* owner_pointer_get */ nullptr,
 
     /* blend_write */ curve_blend_write,
     /* blend_read_data */ curve_blend_read_data,
@@ -2247,7 +2247,7 @@ static void minimum_twist_between_two_points(BevPoint *current_point, BevPoint *
 
 static void make_bevel_list_3D_minimum_twist(BevList *bl)
 {
-  BevPoint *bevp2, *bevp1, *bevp0; /* standard for all make_bevel_list_3D_* funcs */
+  BevPoint *bevp2, *bevp1, *bevp0; /* Standard for all make_bevel_list_3D_* functions. */
   int nr;
   float q[4];
 
@@ -2358,7 +2358,7 @@ static void make_bevel_list_3D_minimum_twist(BevList *bl)
 
 static void make_bevel_list_3D_tangent(BevList *bl)
 {
-  BevPoint *bevp2, *bevp1, *bevp0; /* standard for all make_bevel_list_3D_* funcs */
+  BevPoint *bevp2, *bevp1, *bevp0; /* Standard for all make_bevel_list_3D_* functions. */
   int nr;
 
   float bevp0_tan[3];
@@ -2470,7 +2470,7 @@ static void make_bevel_list_segment_2D(BevList *bl)
 
 static void make_bevel_list_2D(BevList *bl)
 {
-  /* NOTE(campbell): `bevp->dir` and `bevp->quat` are not needed for beveling but are
+  /* NOTE(@campbellbarton): `bevp->dir` and `bevp->quat` are not needed for beveling but are
    * used when making a path from a 2D curve, therefore they need to be set. */
 
   BevPoint *bevp0, *bevp1, *bevp2;
diff --git a/source/blender/blenkernel/intern/curve_catmull_rom.cc b/source/blender/blenkernel/intern/curve_catmull_rom.cc
index 952d59edcf9..b5f1a7cc450 100644
--- a/source/blender/blenkernel/intern/curve_catmull_rom.cc
+++ b/source/blender/blenkernel/intern/curve_catmull_rom.cc
@@ -17,16 +17,14 @@ int calculate_evaluated_num(const int points_num, const bool cyclic, const int r
 }
 
 /* Adapted from Cycles #catmull_rom_basis_eval function. */
-template
-static T calculate_basis(const T &a, const T &b, const T &c, const T &d, const float parameter)
+void calculate_basis(const float parameter, float4 &r_weights)
 {
   const float t = parameter;
   const float s = 1.0f - parameter;
-  const float n0 = -t * s * s;
-  const float n1 = 2.0f + t * t * (3.0f * t - 5.0f);
-  const float n2 = 2.0f + s * s * (3.0f * s - 5.0f);
-  const float n3 = -s * t * t;
-  return 0.5f * (a * n0 + b * n1 + c * n2 + d * n3);
+  r_weights[0] = -t * s * s;
+  r_weights[1] = 2.0f + t * t * (3.0f * t - 5.0f);
+  r_weights[2] = 2.0f + s * s * (3.0f * s - 5.0f);
+  r_weights[3] = -s * t * t;
 }
 
 template
@@ -35,7 +33,7 @@ static void evaluate_segment(const T &a, const T &b, const T &c, const T &d, Mut
   const float step = 1.0f / dst.size();
   dst.first() = b;
   for (const int i : dst.index_range().drop_front(1)) {
-    dst[i] = calculate_basis(a, b, c, d, i * step);
+    dst[i] = interpolate(a, b, c, d, i * step);
   }
 }
 
@@ -141,11 +139,7 @@ void interpolate_to_evaluated(const GSpan src,
 {
   attribute_math::convert_to_static_type(src.type(), [&](auto dummy) {
     using T = decltype(dummy);
-    /* TODO: Use DefaultMixer or other generic mixing in the basis evaluation function to simplify
-     * supporting more types. */
-    if constexpr (is_same_any_v) {
-      interpolate_to_evaluated(src.typed(), cyclic, resolution, dst.typed());
-    }
+    interpolate_to_evaluated(src.typed(), cyclic, resolution, dst.typed());
   });
 }
 
@@ -156,11 +150,7 @@ void interpolate_to_evaluated(const GSpan src,
 {
   attribute_math::convert_to_static_type(src.type(), [&](auto dummy) {
     using T = decltype(dummy);
-    /* TODO: Use DefaultMixer or other generic mixing in the basis evaluation function to simplify
-     * supporting more types. */
-    if constexpr (is_same_any_v) {
-      interpolate_to_evaluated(src.typed(), cyclic, evaluated_offsets, dst.typed());
-    }
+    interpolate_to_evaluated(src.typed(), cyclic, evaluated_offsets, dst.typed());
   });
 }
 
diff --git a/source/blender/blenkernel/intern/curve_eval.cc b/source/blender/blenkernel/intern/curve_eval.cc
deleted file mode 100644
index 424fa311dc7..00000000000
--- a/source/blender/blenkernel/intern/curve_eval.cc
+++ /dev/null
@@ -1,587 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-
-#include "BLI_array.hh"
-#include "BLI_index_range.hh"
-#include "BLI_listbase.h"
-#include "BLI_map.hh"
-#include "BLI_span.hh"
-#include "BLI_string_ref.hh"
-#include "BLI_task.hh"
-#include "BLI_vector.hh"
-
-#include "DNA_curve_types.h"
-
-#include "BKE_anonymous_attribute.hh"
-#include "BKE_curve.h"
-#include "BKE_curves.hh"
-#include "BKE_geometry_set.hh"
-#include "BKE_spline.hh"
-
-using blender::Array;
-using blender::float3;
-using blender::float4x4;
-using blender::GVArray;
-using blender::GVArraySpan;
-using blender::IndexRange;
-using blender::Map;
-using blender::MutableSpan;
-using blender::Span;
-using blender::StringRefNull;
-using blender::VArray;
-using blender::VArraySpan;
-using blender::Vector;
-using blender::bke::AttributeIDRef;
-using blender::bke::AttributeMetaData;
-
-blender::Span CurveEval::splines() const
-{
-  return splines_;
-}
-
-blender::MutableSpan CurveEval::splines()
-{
-  return splines_;
-}
-
-bool CurveEval::has_spline_with_type(const CurveType type) const
-{
-  for (const SplinePtr &spline : this->splines()) {
-    if (spline->type() == type) {
-      return true;
-    }
-  }
-  return false;
-}
-
-void CurveEval::resize(const int size)
-{
-  splines_.resize(size);
-  attributes.reallocate(size);
-}
-
-void CurveEval::add_spline(SplinePtr spline)
-{
-  splines_.append(std::move(spline));
-}
-
-void CurveEval::add_splines(MutableSpan splines)
-{
-  for (SplinePtr &spline : splines) {
-    this->add_spline(std::move(spline));
-  }
-}
-
-void CurveEval::remove_splines(blender::IndexMask mask)
-{
-  for (int i = mask.size() - 1; i >= 0; i--) {
-    splines_.remove_and_reorder(mask.indices()[i]);
-  }
-}
-
-void CurveEval::translate(const float3 &translation)
-{
-  for (SplinePtr &spline : this->splines()) {
-    spline->translate(translation);
-    spline->mark_cache_invalid();
-  }
-}
-
-void CurveEval::transform(const float4x4 &matrix)
-{
-  for (SplinePtr &spline : this->splines()) {
-    spline->transform(matrix);
-  }
-}
-
-bool CurveEval::bounds_min_max(float3 &min, float3 &max, const bool use_evaluated) const
-{
-  bool have_minmax = false;
-  for (const SplinePtr &spline : this->splines()) {
-    if (spline->size()) {
-      spline->bounds_min_max(min, max, use_evaluated);
-      have_minmax = true;
-    }
-  }
-
-  return have_minmax;
-}
-
-float CurveEval::total_length() const
-{
-  float length = 0.0f;
-  for (const SplinePtr &spline : this->splines()) {
-    length += spline->length();
-  }
-  return length;
-}
-
-int CurveEval::total_control_point_num() const
-{
-  int count = 0;
-  for (const SplinePtr &spline : this->splines()) {
-    count += spline->size();
-  }
-  return count;
-}
-
-blender::Array CurveEval::control_point_offsets() const
-{
-  Array offsets(splines_.size() + 1);
-  int offset = 0;
-  for (const int i : splines_.index_range()) {
-    offsets[i] = offset;
-    offset += splines_[i]->size();
-  }
-  offsets.last() = offset;
-  return offsets;
-}
-
-blender::Array CurveEval::evaluated_point_offsets() const
-{
-  Array offsets(splines_.size() + 1);
-  int offset = 0;
-  for (const int i : splines_.index_range()) {
-    offsets[i] = offset;
-    offset += splines_[i]->evaluated_points_num();
-  }
-  offsets.last() = offset;
-  return offsets;
-}
-
-blender::Array CurveEval::accumulated_spline_lengths() const
-{
-  Array spline_lengths(splines_.size() + 1);
-  float spline_length = 0.0f;
-  for (const int i : splines_.index_range()) {
-    spline_lengths[i] = spline_length;
-    spline_length += splines_[i]->length();
-  }
-  spline_lengths.last() = spline_length;
-  return spline_lengths;
-}
-
-void CurveEval::mark_cache_invalid()
-{
-  for (SplinePtr &spline : splines_) {
-    spline->mark_cache_invalid();
-  }
-}
-
-static HandleType handle_type_from_dna_bezt(const eBezTriple_Handle dna_handle_type)
-{
-  switch (dna_handle_type) {
-    case HD_FREE:
-      return BEZIER_HANDLE_FREE;
-    case HD_AUTO:
-      return BEZIER_HANDLE_AUTO;
-    case HD_VECT:
-      return BEZIER_HANDLE_VECTOR;
-    case HD_ALIGN:
-      return BEZIER_HANDLE_ALIGN;
-    case HD_AUTO_ANIM:
-      return BEZIER_HANDLE_AUTO;
-    case HD_ALIGN_DOUBLESIDE:
-      return BEZIER_HANDLE_ALIGN;
-  }
-  BLI_assert_unreachable();
-  return BEZIER_HANDLE_AUTO;
-}
-
-static NormalMode normal_mode_from_dna_curve(const int twist_mode)
-{
-  switch (twist_mode) {
-    case CU_TWIST_Z_UP:
-    case CU_TWIST_TANGENT:
-      return NORMAL_MODE_Z_UP;
-    case CU_TWIST_MINIMUM:
-      return NORMAL_MODE_MINIMUM_TWIST;
-  }
-  BLI_assert_unreachable();
-  return NORMAL_MODE_MINIMUM_TWIST;
-}
-
-static KnotsMode knots_mode_from_dna_nurb(const short flag)
-{
-  switch (flag & (CU_NURB_ENDPOINT | CU_NURB_BEZIER)) {
-    case CU_NURB_ENDPOINT:
-      return NURBS_KNOT_MODE_ENDPOINT;
-    case CU_NURB_BEZIER:
-      return NURBS_KNOT_MODE_BEZIER;
-    case CU_NURB_ENDPOINT | CU_NURB_BEZIER:
-      return NURBS_KNOT_MODE_ENDPOINT_BEZIER;
-    default:
-      return NURBS_KNOT_MODE_NORMAL;
-  }
-
-  BLI_assert_unreachable();
-  return NURBS_KNOT_MODE_NORMAL;
-}
-
-static SplinePtr spline_from_dna_bezier(const Nurb &nurb)
-{
-  std::unique_ptr spline = std::make_unique();
-  spline->set_resolution(nurb.resolu);
-  spline->set_cyclic(nurb.flagu & CU_NURB_CYCLIC);
-
-  Span src_points{nurb.bezt, nurb.pntsu};
-  spline->resize(src_points.size());
-  MutableSpan positions = spline->positions();
-  MutableSpan handle_positions_left = spline->handle_positions_left(true);
-  MutableSpan handle_positions_right = spline->handle_positions_right(true);
-  MutableSpan handle_types_left = spline->handle_types_left();
-  MutableSpan handle_types_right = spline->handle_types_right();
-  MutableSpan radii = spline->radii();
-  MutableSpan tilts = spline->tilts();
-
-  blender::threading::parallel_for(src_points.index_range(), 2048, [&](IndexRange range) {
-    for (const int i : range) {
-      const BezTriple &bezt = src_points[i];
-      positions[i] = bezt.vec[1];
-      handle_positions_left[i] = bezt.vec[0];
-      handle_types_left[i] = handle_type_from_dna_bezt((eBezTriple_Handle)bezt.h1);
-      handle_positions_right[i] = bezt.vec[2];
-      handle_types_right[i] = handle_type_from_dna_bezt((eBezTriple_Handle)bezt.h2);
-      radii[i] = bezt.radius;
-      tilts[i] = bezt.tilt;
-    }
-  });
-
-  return spline;
-}
-
-static SplinePtr spline_from_dna_nurbs(const Nurb &nurb)
-{
-  std::unique_ptr spline = std::make_unique();
-  spline->set_resolution(nurb.resolu);
-  spline->set_cyclic(nurb.flagu & CU_NURB_CYCLIC);
-  spline->set_order(nurb.orderu);
-  spline->knots_mode = knots_mode_from_dna_nurb(nurb.flagu);
-
-  Span src_points{nurb.bp, nurb.pntsu};
-  spline->resize(src_points.size());
-  MutableSpan positions = spline->positions();
-  MutableSpan weights = spline->weights();
-  MutableSpan radii = spline->radii();
-  MutableSpan tilts = spline->tilts();
-
-  blender::threading::parallel_for(src_points.index_range(), 2048, [&](IndexRange range) {
-    for (const int i : range) {
-      const BPoint &bp = src_points[i];
-      positions[i] = bp.vec;
-      weights[i] = bp.vec[3];
-      radii[i] = bp.radius;
-      tilts[i] = bp.tilt;
-    }
-  });
-
-  return spline;
-}
-
-static SplinePtr spline_from_dna_poly(const Nurb &nurb)
-{
-  std::unique_ptr spline = std::make_unique();
-  spline->set_cyclic(nurb.flagu & CU_NURB_CYCLIC);
-
-  Span src_points{nurb.bp, nurb.pntsu};
-  spline->resize(src_points.size());
-  MutableSpan positions = spline->positions();
-  MutableSpan radii = spline->radii();
-  MutableSpan tilts = spline->tilts();
-
-  blender::threading::parallel_for(src_points.index_range(), 2048, [&](IndexRange range) {
-    for (const int i : range) {
-      const BPoint &bp = src_points[i];
-      positions[i] = bp.vec;
-      radii[i] = bp.radius;
-      tilts[i] = bp.tilt;
-    }
-  });
-
-  return spline;
-}
-
-std::unique_ptr curve_eval_from_dna_curve(const Curve &dna_curve,
-                                                     const ListBase &nurbs_list)
-{
-  Vector nurbs(nurbs_list);
-
-  std::unique_ptr curve = std::make_unique();
-  curve->resize(nurbs.size());
-  MutableSpan splines = curve->splines();
-
-  blender::threading::parallel_for(nurbs.index_range(), 256, [&](IndexRange range) {
-    for (const int i : range) {
-      switch (nurbs[i]->type) {
-        case CU_BEZIER:
-          splines[i] = spline_from_dna_bezier(*nurbs[i]);
-          break;
-        case CU_NURBS:
-          splines[i] = spline_from_dna_nurbs(*nurbs[i]);
-          break;
-        case CU_POLY:
-          splines[i] = spline_from_dna_poly(*nurbs[i]);
-          break;
-        default:
-          BLI_assert_unreachable();
-          break;
-      }
-    }
-  });
-
-  /* Normal mode is stored separately in each spline to facilitate combining
-   * splines from multiple curve objects, where the value may be different. */
-  const NormalMode normal_mode = normal_mode_from_dna_curve(dna_curve.twist_mode);
-  for (SplinePtr &spline : curve->splines()) {
-    spline->normal_mode = normal_mode;
-  }
-
-  return curve;
-}
-
-std::unique_ptr curve_eval_from_dna_curve(const Curve &dna_curve)
-{
-  return curve_eval_from_dna_curve(dna_curve, *BKE_curve_nurbs_get_for_read(&dna_curve));
-}
-
-static void copy_attributes_between_components(
-    const blender::bke::AttributeAccessor &src_attributes,
-    blender::bke::MutableAttributeAccessor &dst_attributes,
-    Span skip)
-{
-  src_attributes.for_all([&](const AttributeIDRef &id, const AttributeMetaData meta_data) {
-    if (id.is_named() && skip.contains(id.name())) {
-      return true;
-    }
-
-    GVArray src_attribute = src_attributes.lookup(id, meta_data.domain, meta_data.data_type);
-    if (!src_attribute) {
-      return true;
-    }
-    GVArraySpan src_attribute_data{src_attribute};
-
-    blender::bke::GAttributeWriter dst_attribute = dst_attributes.lookup_or_add_for_write(
-        id, meta_data.domain, meta_data.data_type);
-    if (!dst_attribute) {
-      return true;
-    }
-    dst_attribute.varray.set_all(src_attribute_data.data());
-    dst_attribute.finish();
-    return true;
-  });
-}
-
-std::unique_ptr curves_to_curve_eval(const Curves &curves_id)
-{
-  CurveComponent src_component;
-  src_component.replace(&const_cast(curves_id), GeometryOwnershipType::ReadOnly);
-  const blender::bke::CurvesGeometry &curves = blender::bke::CurvesGeometry::wrap(
-      curves_id.geometry);
-  const blender::bke::AttributeAccessor src_attributes = curves.attributes();
-
-  VArray resolution = curves.resolution();
-  VArray normal_mode = curves.normal_mode();
-
-  VArraySpan nurbs_weights{
-      src_attributes.lookup_or_default("nurbs_weight", ATTR_DOMAIN_POINT, 0.0f)};
-  VArraySpan nurbs_orders{
-      src_attributes.lookup_or_default("nurbs_order", ATTR_DOMAIN_CURVE, 4)};
-  VArraySpan nurbs_knots_modes{
-      src_attributes.lookup_or_default("knots_mode", ATTR_DOMAIN_CURVE, 0)};
-
-  VArraySpan handle_types_right{
-      src_attributes.lookup_or_default("handle_type_right", ATTR_DOMAIN_POINT, 0)};
-  VArraySpan handle_types_left{
-      src_attributes.lookup_or_default("handle_type_left", ATTR_DOMAIN_POINT, 0)};
-
-  /* Create splines with the correct size and type. */
-  VArray curve_types = curves.curve_types();
-  std::unique_ptr curve_eval = std::make_unique();
-  for (const int curve_index : curve_types.index_range()) {
-    const IndexRange points = curves.points_for_curve(curve_index);
-
-    std::unique_ptr spline;
-    /* #CurveEval does not support catmull rom curves, so convert those to poly splines. */
-    switch (std::max(1, curve_types[curve_index])) {
-      case CURVE_TYPE_POLY: {
-        spline = std::make_unique();
-        spline->resize(points.size());
-        break;
-      }
-      case CURVE_TYPE_BEZIER: {
-        std::unique_ptr bezier_spline = std::make_unique();
-        bezier_spline->resize(points.size());
-        bezier_spline->set_resolution(resolution[curve_index]);
-        bezier_spline->handle_types_left().copy_from(handle_types_left.slice(points));
-        bezier_spline->handle_types_right().copy_from(handle_types_right.slice(points));
-
-        spline = std::move(bezier_spline);
-        break;
-      }
-      case CURVE_TYPE_NURBS: {
-        std::unique_ptr nurb_spline = std::make_unique();
-        nurb_spline->resize(points.size());
-        nurb_spline->set_resolution(resolution[curve_index]);
-        nurb_spline->weights().copy_from(nurbs_weights.slice(points));
-        nurb_spline->set_order(nurbs_orders[curve_index]);
-        nurb_spline->knots_mode = static_cast(nurbs_knots_modes[curve_index]);
-
-        spline = std::move(nurb_spline);
-        break;
-      }
-      case CURVE_TYPE_CATMULL_ROM:
-        /* Not supported yet. */
-        BLI_assert_unreachable();
-        continue;
-    }
-    spline->positions().fill(float3(0));
-    spline->tilts().fill(0.0f);
-    spline->radii().fill(1.0f);
-    spline->normal_mode = static_cast(normal_mode[curve_index]);
-    curve_eval->add_spline(std::move(spline));
-  }
-
-  curve_eval->attributes.reallocate(curve_eval->splines().size());
-
-  CurveComponentLegacy dst_component;
-  dst_component.replace(curve_eval.get(), GeometryOwnershipType::Editable);
-  blender::bke::MutableAttributeAccessor dst_attributes = *dst_component.attributes_for_write();
-
-  copy_attributes_between_components(src_attributes,
-                                     dst_attributes,
-                                     {"curve_type",
-                                      "resolution",
-                                      "normal_mode",
-                                      "nurbs_weight",
-                                      "nurbs_order",
-                                      "knots_mode",
-                                      "handle_type_right",
-                                      "handle_type_left"});
-
-  return curve_eval;
-}
-
-Curves *curve_eval_to_curves(const CurveEval &curve_eval)
-{
-  Curves *curves_id = blender::bke::curves_new_nomain(curve_eval.total_control_point_num(),
-                                                      curve_eval.splines().size());
-  CurveComponent dst_component;
-  dst_component.replace(curves_id, GeometryOwnershipType::Editable);
-  blender::bke::MutableAttributeAccessor dst_attributes = *dst_component.attributes_for_write();
-
-  blender::bke::CurvesGeometry &curves = blender::bke::CurvesGeometry::wrap(curves_id->geometry);
-  curves.offsets_for_write().copy_from(curve_eval.control_point_offsets());
-  MutableSpan curve_types = curves.curve_types_for_write();
-
-  blender::bke::SpanAttributeWriter normal_mode =
-      dst_attributes.lookup_or_add_for_write_only_span("normal_mode", ATTR_DOMAIN_CURVE);
-  blender::bke::SpanAttributeWriter nurbs_weight;
-  blender::bke::SpanAttributeWriter nurbs_order;
-  blender::bke::SpanAttributeWriter nurbs_knots_mode;
-  if (curve_eval.has_spline_with_type(CURVE_TYPE_NURBS)) {
-    nurbs_weight = dst_attributes.lookup_or_add_for_write_only_span("nurbs_weight",
-                                                                           ATTR_DOMAIN_POINT);
-    nurbs_order = dst_attributes.lookup_or_add_for_write_only_span("nurbs_order",
-                                                                        ATTR_DOMAIN_CURVE);
-    nurbs_knots_mode = dst_attributes.lookup_or_add_for_write_only_span("knots_mode",
-                                                                                ATTR_DOMAIN_CURVE);
-  }
-  blender::bke::SpanAttributeWriter handle_type_right;
-  blender::bke::SpanAttributeWriter handle_type_left;
-  if (curve_eval.has_spline_with_type(CURVE_TYPE_BEZIER)) {
-    handle_type_right = dst_attributes.lookup_or_add_for_write_only_span(
-        "handle_type_right", ATTR_DOMAIN_POINT);
-    handle_type_left = dst_attributes.lookup_or_add_for_write_only_span("handle_type_left",
-                                                                                ATTR_DOMAIN_POINT);
-  }
-
-  for (const int curve_index : curve_eval.splines().index_range()) {
-    const Spline &spline = *curve_eval.splines()[curve_index];
-    curve_types[curve_index] = curve_eval.splines()[curve_index]->type();
-    normal_mode.span[curve_index] = curve_eval.splines()[curve_index]->normal_mode;
-    const IndexRange points = curves.points_for_curve(curve_index);
-
-    switch (spline.type()) {
-      case CURVE_TYPE_POLY:
-        break;
-      case CURVE_TYPE_BEZIER: {
-        const BezierSpline &src = static_cast(spline);
-        handle_type_right.span.slice(points).copy_from(src.handle_types_right());
-        handle_type_left.span.slice(points).copy_from(src.handle_types_left());
-        break;
-      }
-      case CURVE_TYPE_NURBS: {
-        const NURBSpline &src = static_cast(spline);
-        nurbs_knots_mode.span[curve_index] = static_cast(src.knots_mode);
-        nurbs_order.span[curve_index] = src.order();
-        nurbs_weight.span.slice(points).copy_from(src.weights());
-        break;
-      }
-      case CURVE_TYPE_CATMULL_ROM: {
-        BLI_assert_unreachable();
-        break;
-      }
-    }
-  }
-
-  curves.update_curve_types();
-
-  normal_mode.finish();
-  nurbs_weight.finish();
-  nurbs_order.finish();
-  nurbs_knots_mode.finish();
-  handle_type_right.finish();
-  handle_type_left.finish();
-
-  CurveComponentLegacy src_component;
-  src_component.replace(&const_cast(curve_eval), GeometryOwnershipType::ReadOnly);
-  const blender::bke::AttributeAccessor src_attributes = *src_component.attributes();
-
-  copy_attributes_between_components(src_attributes, dst_attributes, {});
-
-  return curves_id;
-}
-
-void CurveEval::assert_valid_point_attributes() const
-{
-#ifdef DEBUG
-  if (splines_.size() == 0) {
-    return;
-  }
-  const int layer_len = splines_.first()->attributes.data.totlayer;
-
-  Array ids_in_order(layer_len);
-  Array meta_data_in_order(layer_len);
-
-  {
-    int i = 0;
-    splines_.first()->attributes.foreach_attribute(
-        [&](const AttributeIDRef &attribute_id, const AttributeMetaData &meta_data) {
-          ids_in_order[i] = attribute_id;
-          meta_data_in_order[i] = meta_data;
-          i++;
-          return true;
-        },
-        ATTR_DOMAIN_POINT);
-  }
-
-  for (const SplinePtr &spline : splines_) {
-    /* All splines should have the same number of attributes. */
-    BLI_assert(spline->attributes.data.totlayer == layer_len);
-
-    int i = 0;
-    spline->attributes.foreach_attribute(
-        [&](const AttributeIDRef &attribute_id, const AttributeMetaData &meta_data) {
-          /* Attribute names and IDs should have the same order and exist on all splines. */
-          BLI_assert(attribute_id == ids_in_order[i]);
-
-          /* Attributes with the same ID different splines should all have the same type. */
-          BLI_assert(meta_data == meta_data_in_order[i]);
-
-          i++;
-          return true;
-        },
-        ATTR_DOMAIN_POINT);
-  }
-
-#endif
-}
diff --git a/source/blender/blenkernel/intern/curve_legacy_convert.cc b/source/blender/blenkernel/intern/curve_legacy_convert.cc
index ff5bbc32afe..938dcbd6269 100644
--- a/source/blender/blenkernel/intern/curve_legacy_convert.cc
+++ b/source/blender/blenkernel/intern/curve_legacy_convert.cc
@@ -115,7 +115,7 @@ Curves *curve_legacy_to_curves(const Curve &curve_legacy, const ListBase &nurbs_
   MutableSpan tilts = curves.tilt_for_write();
 
   auto create_poly = [&](IndexMask selection) {
-    threading::parallel_for(selection.index_range(), 246, [&](IndexRange range) {
+    threading::parallel_for(selection.index_range(), 256, [&](IndexRange range) {
       for (const int curve_i : selection.slice(range)) {
         const Nurb &src_curve = *src_curves[curve_i];
         const Span src_points(src_curve.bp, src_curve.pntsu);
@@ -142,7 +142,7 @@ Curves *curve_legacy_to_curves(const Curve &curve_legacy, const ListBase &nurbs_
     MutableSpan handle_types_l = curves.handle_types_left_for_write();
     MutableSpan handle_types_r = curves.handle_types_right_for_write();
 
-    threading::parallel_for(selection.index_range(), 246, [&](IndexRange range) {
+    threading::parallel_for(selection.index_range(), 256, [&](IndexRange range) {
       for (const int curve_i : selection.slice(range)) {
         const Nurb &src_curve = *src_curves[curve_i];
         const Span src_points(src_curve.bezt, src_curve.pntsu);
@@ -165,12 +165,12 @@ Curves *curve_legacy_to_curves(const Curve &curve_legacy, const ListBase &nurbs_
   };
 
   auto create_nurbs = [&](IndexMask selection) {
-    threading::parallel_for(selection.index_range(), 246, [&](IndexRange range) {
-      MutableSpan resolutions = curves.resolution_for_write();
-      MutableSpan nurbs_weights = curves.nurbs_weights_for_write();
-      MutableSpan nurbs_orders = curves.nurbs_orders_for_write();
-      MutableSpan nurbs_knots_modes = curves.nurbs_knots_modes_for_write();
+    MutableSpan resolutions = curves.resolution_for_write();
+    MutableSpan nurbs_weights = curves.nurbs_weights_for_write();
+    MutableSpan nurbs_orders = curves.nurbs_orders_for_write();
+    MutableSpan nurbs_knots_modes = curves.nurbs_knots_modes_for_write();
 
+    threading::parallel_for(selection.index_range(), 256, [&](IndexRange range) {
       for (const int curve_i : selection.slice(range)) {
         const Nurb &src_curve = *src_curves[curve_i];
         const Span src_points(src_curve.bp, src_curve.pntsu);
diff --git a/source/blender/blenkernel/intern/curve_nurbs.cc b/source/blender/blenkernel/intern/curve_nurbs.cc
index 3ab6fb01ea5..62d5682da0f 100644
--- a/source/blender/blenkernel/intern/curve_nurbs.cc
+++ b/source/blender/blenkernel/intern/curve_nurbs.cc
@@ -4,8 +4,9 @@
  * \ingroup bke
  */
 
-#include "BKE_attribute_math.hh"
+#include "BLI_task.hh"
 
+#include "BKE_attribute_math.hh"
 #include "BKE_curves.hh"
 
 namespace blender::bke::curves::nurbs {
@@ -192,16 +193,16 @@ static void interpolate_to_evaluated(const BasisCache &basis_cache,
 {
   attribute_math::DefaultMixer mixer{dst};
 
-  for (const int i : dst.index_range()) {
-    Span point_weights = basis_cache.weights.as_span().slice(i * order, order);
-
-    for (const int j : point_weights.index_range()) {
-      const int point_index = (basis_cache.start_indices[i] + j) % src.size();
-      mixer.mix_in(i, src[point_index], point_weights[j]);
+  threading::parallel_for(dst.index_range(), 128, [&](const IndexRange range) {
+    for (const int i : range) {
+      Span point_weights = basis_cache.weights.as_span().slice(i * order, order);
+      for (const int j : point_weights.index_range()) {
+        const int point_index = (basis_cache.start_indices[i] + j) % src.size();
+        mixer.mix_in(i, src[point_index], point_weights[j]);
+      }
     }
-  }
-
-  mixer.finalize();
+    mixer.finalize(range);
+  });
 }
 
 template
@@ -213,17 +214,18 @@ static void interpolate_to_evaluated_rational(const BasisCache &basis_cache,
 {
   attribute_math::DefaultMixer mixer{dst};
 
-  for (const int i : dst.index_range()) {
-    Span point_weights = basis_cache.weights.as_span().slice(i * order, order);
+  threading::parallel_for(dst.index_range(), 128, [&](const IndexRange range) {
+    for (const int i : range) {
+      Span point_weights = basis_cache.weights.as_span().slice(i * order, order);
 
-    for (const int j : point_weights.index_range()) {
-      const int point_index = (basis_cache.start_indices[i] + j) % src.size();
-      const float weight = point_weights[j] * control_weights[point_index];
-      mixer.mix_in(i, src[point_index], weight);
+      for (const int j : point_weights.index_range()) {
+        const int point_index = (basis_cache.start_indices[i] + j) % src.size();
+        const float weight = point_weights[j] * control_weights[point_index];
+        mixer.mix_in(i, src[point_index], weight);
+      }
     }
-  }
-
-  mixer.finalize();
+    mixer.finalize(range);
+  });
 }
 
 void interpolate_to_evaluated(const BasisCache &basis_cache,
diff --git a/source/blender/blenkernel/intern/curve_poly.cc b/source/blender/blenkernel/intern/curve_poly.cc
index 7ab92068d81..2b2cf9adeee 100644
--- a/source/blender/blenkernel/intern/curve_poly.cc
+++ b/source/blender/blenkernel/intern/curve_poly.cc
@@ -65,8 +65,21 @@ void calculate_tangents(const Span positions,
     tangents.last() = direction_bisect(second_to_last, last, first, used_fallback);
   }
   else {
-    tangents.first() = math::normalize(positions[1] - positions.first());
-    tangents.last() = math::normalize(positions.last() - positions[positions.size() - 2]);
+    const float epsilon = 1e-6f;
+    if (math::almost_equal_relative(positions[0], positions[1], epsilon)) {
+      tangents.first() = {0.0f, 0.0f, 0.0f};
+      used_fallback = true;
+    }
+    else {
+      tangents.first() = math::normalize(positions[1] - positions[0]);
+    }
+    if (math::almost_equal_relative(positions.last(0), positions.last(1), epsilon)) {
+      tangents.last() = {0.0f, 0.0f, 0.0f};
+      used_fallback = true;
+    }
+    else {
+      tangents.last() = math::normalize(positions.last(0) - positions.last(1));
+    }
   }
 
   if (!used_fallback) {
diff --git a/source/blender/blenkernel/intern/curve_to_mesh_convert.cc b/source/blender/blenkernel/intern/curve_to_mesh_convert.cc
index 7f051b683b4..b9fea2a27b8 100644
--- a/source/blender/blenkernel/intern/curve_to_mesh_convert.cc
+++ b/source/blender/blenkernel/intern/curve_to_mesh_convert.cc
@@ -640,10 +640,10 @@ Mesh *curve_to_mesh_sweep(const CurvesGeometry &main,
       offsets.vert.last(), offsets.edge.last(), 0, offsets.loop.last(), offsets.poly.last());
   mesh->flag |= ME_AUTOSMOOTH;
   mesh->smoothresh = DEG2RADF(180.0f);
-  MutableSpan verts(mesh->mvert, mesh->totvert);
-  MutableSpan edges(mesh->medge, mesh->totedge);
-  MutableSpan loops(mesh->mloop, mesh->totloop);
-  MutableSpan polys(mesh->mpoly, mesh->totpoly);
+  MutableSpan verts = mesh->verts_for_write();
+  MutableSpan edges = mesh->edges_for_write();
+  MutableSpan polys = mesh->polys_for_write();
+  MutableSpan loops = mesh->loops_for_write();
 
   foreach_curve_combination(curves_info, offsets, [&](const CombinationInfo &info) {
     fill_mesh_topology(info.vert_range.start(),
@@ -711,7 +711,7 @@ Mesh *curve_to_mesh_sweep(const CurvesGeometry &main,
 
   Set main_attributes_set;
 
-  MutableAttributeAccessor mesh_attributes = bke::mesh_attributes_for_write(*mesh);
+  MutableAttributeAccessor mesh_attributes = mesh->attributes_for_write();
 
   main_attributes.for_all([&](const AttributeIDRef &id, const AttributeMetaData meta_data) {
     if (!should_add_attribute_to_mesh(main_attributes, mesh_attributes, id)) {
diff --git a/source/blender/blenkernel/intern/curves.cc b/source/blender/blenkernel/intern/curves.cc
index 78791b55b4d..d801484de62 100644
--- a/source/blender/blenkernel/intern/curves.cc
+++ b/source/blender/blenkernel/intern/curves.cc
@@ -53,8 +53,6 @@ using blender::Vector;
 
 static const char *ATTR_POSITION = "position";
 
-static void update_custom_data_pointers(Curves &curves);
-
 static void curves_init_data(ID *id)
 {
   Curves *curves = (Curves *)id;
@@ -97,8 +95,6 @@ static void curves_copy_data(Main *UNUSED(bmain), ID *id_dst, const ID *id_src,
 
   dst.runtime->type_counts = src.runtime->type_counts;
 
-  dst.update_customdata_pointers();
-
   curves_dst->batch_cache = nullptr;
 }
 
@@ -170,7 +166,6 @@ static void curves_blend_read_data(BlendDataReader *reader, ID *id)
   /* Geometry */
   CustomData_blend_read(reader, &curves->geometry.point_data, curves->geometry.point_num);
   CustomData_blend_read(reader, &curves->geometry.curve_data, curves->geometry.curve_num);
-  update_custom_data_pointers(*curves);
 
   BLO_read_int32_array(reader, curves->geometry.curve_num + 1, &curves->geometry.curve_offsets);
 
@@ -204,40 +199,35 @@ static void curves_blend_read_expand(BlendExpander *expander, ID *id)
 }
 
 IDTypeInfo IDType_ID_CV = {
-    /*id_code */ ID_CV,
-    /*id_filter */ FILTER_ID_CV,
-    /*main_listbase_index */ INDEX_ID_CV,
-    /*struct_size */ sizeof(Curves),
-    /*name */ "Curves",
-    /*name_plural */ "curves",
-    /*translation_context */ BLT_I18NCONTEXT_ID_CURVES,
-    /*flags */ IDTYPE_FLAGS_APPEND_IS_REUSABLE,
-    /*asset_type_info */ nullptr,
-
-    /*init_data */ curves_init_data,
-    /*copy_data */ curves_copy_data,
-    /*free_data */ curves_free_data,
-    /*make_local */ nullptr,
-    /*foreach_id */ curves_foreach_id,
-    /*foreach_cache */ nullptr,
-    /*foreach_path */ nullptr,
-    /*owner_get */ nullptr,
-
-    /*blend_write */ curves_blend_write,
-    /*blend_read_data */ curves_blend_read_data,
-    /*blend_read_lib */ curves_blend_read_lib,
-    /*blend_read_expand */ curves_blend_read_expand,
-
-    /*blend_read_undo_preserve */ nullptr,
-
-    /*lib_override_apply_post */ nullptr,
+    /* id_code */ ID_CV,
+    /* id_filter */ FILTER_ID_CV,
+    /* main_listbase_index */ INDEX_ID_CV,
+    /* struct_size */ sizeof(Curves),
+    /* name*/ "Curves",
+    /* name_plural */ "hair_curves",
+    /* translation_context */ BLT_I18NCONTEXT_ID_CURVES,
+    /* flags */ IDTYPE_FLAGS_APPEND_IS_REUSABLE,
+    /* asset_type_info */ nullptr,
+
+    /* init_data */ curves_init_data,
+    /* copy_data */ curves_copy_data,
+    /* free_data */ curves_free_data,
+    /* make_local */ nullptr,
+    /* foreach_id */ curves_foreach_id,
+    /* foreach_cache */ nullptr,
+    /* foreach_path */ nullptr,
+    /* owner_pointer_get */ nullptr,
+
+    /* blend_write */ curves_blend_write,
+    /* blend_read_data */ curves_blend_read_data,
+    /* blend_read_lib */ curves_blend_read_lib,
+    /* blend_read_expand */ curves_blend_read_expand,
+
+    /* blend_read_undo_preserve */ nullptr,
+
+    /* lib_override_apply_post */ nullptr,
 };
 
-static void update_custom_data_pointers(Curves &curves)
-{
-  blender::bke::CurvesGeometry::wrap(curves.geometry).update_customdata_pointers();
-}
-
 void *BKE_curves_add(Main *bmain, const char *name)
 {
   Curves *curves = static_cast(BKE_id_new(bmain, ID_CV, name));
@@ -273,7 +263,7 @@ BoundBox *BKE_curves_boundbox_get(Object *ob)
   return ob->runtime.bb;
 }
 
-bool BKE_curves_customdata_required(const Curves *UNUSED(curves), const char *name)
+bool BKE_curves_attribute_required(const Curves *UNUSED(curves), const char *name)
 {
   return STREQ(name, ATTR_POSITION);
 }
@@ -301,6 +291,8 @@ static void curves_evaluate_modifiers(struct Depsgraph *depsgraph,
   ModifierApplyFlag apply_flag = use_render ? MOD_APPLY_RENDER : MOD_APPLY_USECACHE;
   const ModifierEvalContext mectx = {depsgraph, object, apply_flag};
 
+  BKE_modifiers_clear_errors(object);
+
   /* Get effective list of modifiers to execute. Some effects like shape keys
    * are added as virtual modifiers before the user created modifiers. */
   VirtualModifierData virtualModifierData;
@@ -329,6 +321,14 @@ void BKE_curves_data_update(struct Depsgraph *depsgraph, struct Scene *scene, Ob
   Curves *curves = static_cast(object->data);
   GeometrySet geometry_set = GeometrySet::create_with_curves(curves,
                                                              GeometryOwnershipType::ReadOnly);
+  if (object->mode == OB_MODE_SCULPT_CURVES) {
+    /* Try to propagate deformation data through modifier evaluation, so that sculpt mode can work
+     * on evaluated curves. */
+    GeometryComponentEditData &edit_component =
+        geometry_set.get_component_for_write();
+    edit_component.curves_edit_hints_ = std::make_unique(
+        *static_cast(DEG_get_original_object(object)->data));
+  }
   curves_evaluate_modifiers(depsgraph, scene, object, geometry_set);
 
   /* Assign evaluated object. */
@@ -366,6 +366,8 @@ namespace blender::bke {
 
 Curves *curves_new_nomain(const int points_num, const int curves_num)
 {
+  BLI_assert(points_num >= 0);
+  BLI_assert(curves_num >= 0);
   Curves *curves_id = static_cast(BKE_id_new_nomain(ID_CV, nullptr));
   CurvesGeometry &curves = CurvesGeometry::wrap(curves_id->geometry);
   curves.resize(points_num, curves_num);
@@ -388,6 +390,23 @@ Curves *curves_new_nomain(CurvesGeometry curves)
   return curves_id;
 }
 
+void curves_copy_parameters(const Curves &src, Curves &dst)
+{
+  dst.flag = src.flag;
+  dst.attributes_active_index = src.attributes_active_index;
+  MEM_SAFE_FREE(dst.mat);
+  dst.mat = static_cast(MEM_malloc_arrayN(src.totcol, sizeof(Material *), __func__));
+  dst.totcol = src.totcol;
+  MutableSpan(dst.mat, dst.totcol).copy_from(Span(src.mat, src.totcol));
+  dst.symmetry = src.symmetry;
+  dst.selection_domain = src.selection_domain;
+  dst.surface = src.surface;
+  MEM_SAFE_FREE(dst.surface_uv_map);
+  if (src.surface_uv_map != nullptr) {
+    dst.surface_uv_map = BLI_strdup(src.surface_uv_map);
+  }
+}
+
 CurvesSurfaceTransforms::CurvesSurfaceTransforms(const Object &curves_ob, const Object *surface_ob)
 {
   this->curves_to_world = curves_ob.obmat;
@@ -402,4 +421,20 @@ CurvesSurfaceTransforms::CurvesSurfaceTransforms(const Object &curves_ob, const
   }
 }
 
+bool CurvesEditHints::is_valid() const
+{
+  const int point_num = this->curves_id_orig.geometry.point_num;
+  if (this->positions.has_value()) {
+    if (this->positions->size() != point_num) {
+      return false;
+    }
+  }
+  if (this->deform_mats.has_value()) {
+    if (this->deform_mats->size() != point_num) {
+      return false;
+    }
+  }
+  return true;
+}
+
 }  // namespace blender::bke
diff --git a/source/blender/blenkernel/intern/curves_geometry.cc b/source/blender/blenkernel/intern/curves_geometry.cc
index 8d955a46275..06789e34ad4 100644
--- a/source/blender/blenkernel/intern/curves_geometry.cc
+++ b/source/blender/blenkernel/intern/curves_geometry.cc
@@ -13,6 +13,7 @@
 #include "BLI_index_mask_ops.hh"
 #include "BLI_length_parameterize.hh"
 #include "BLI_math_rotation.hh"
+#include "BLI_task.hh"
 
 #include "DNA_curves_types.h"
 
@@ -57,7 +58,7 @@ CurvesGeometry::CurvesGeometry(const int point_num, const int curve_num)
 
   CustomData_add_layer_named(&this->point_data,
                              CD_PROP_FLOAT3,
-                             CD_DEFAULT,
+                             CD_CONSTRUCT,
                              nullptr,
                              this->point_num,
                              ATTR_POSITION.c_str());
@@ -68,8 +69,6 @@ CurvesGeometry::CurvesGeometry(const int point_num, const int curve_num)
 #endif
   this->offsets_for_write().first() = 0;
 
-  this->update_customdata_pointers();
-
   this->runtime = MEM_new(__func__);
   /* Fill the type counts with the default so they're in a valid state. */
   this->runtime->type_counts[CURVE_TYPE_CATMULL_ROM] = curve_num;
@@ -95,8 +94,6 @@ static void copy_curves_geometry(CurvesGeometry &dst, const CurvesGeometry &src)
 
   /* Though type counts are a cache, they must be copied because they are calculated eagerly. */
   dst.runtime->type_counts = src.runtime->type_counts;
-
-  dst.update_customdata_pointers();
 }
 
 CurvesGeometry::CurvesGeometry(const CurvesGeometry &other)
@@ -130,9 +127,6 @@ static void move_curves_geometry(CurvesGeometry &dst, CurvesGeometry &src)
   MEM_SAFE_FREE(src.curve_offsets);
 
   std::swap(dst.runtime, src.runtime);
-
-  src.update_customdata_pointers();
-  dst.update_customdata_pointers();
 }
 
 CurvesGeometry::CurvesGeometry(CurvesGeometry &&other)
@@ -228,7 +222,7 @@ static MutableSpan get_mutable_attribute(CurvesGeometry &curves,
     return {data, num};
   }
   data = (T *)CustomData_add_layer_named(
-      &custom_data, type, CD_CALLOC, nullptr, num, name.c_str());
+      &custom_data, type, CD_SET_DEFAULT, nullptr, num, name.c_str());
   MutableSpan span = {data, num};
   if (num > 0 && span.first() != default_value) {
     span.fill(default_value);
@@ -261,6 +255,12 @@ void CurvesGeometry::fill_curve_types(const IndexMask selection, const CurveType
     this->fill_curve_types(type);
     return;
   }
+  if (std::optional single_type = this->curve_types().get_if_single()) {
+    if (single_type == type) {
+      /* No need for an array if the types are already a single with the correct type. */
+      return;
+    }
+  }
   /* A potential performance optimization is only counting the changed indices. */
   this->curve_types_for_write().fill_indices(selection, type);
   this->update_curve_types();
@@ -306,13 +306,11 @@ void CurvesGeometry::update_curve_types()
 
 Span CurvesGeometry::positions() const
 {
-  return {(const float3 *)this->position, this->point_num};
+  return get_span_attribute(*this, ATTR_DOMAIN_POINT, ATTR_POSITION);
 }
 MutableSpan CurvesGeometry::positions_for_write()
 {
-  this->position = (float(*)[3])CustomData_duplicate_referenced_layer_named(
-      &this->point_data, CD_PROP_FLOAT3, ATTR_POSITION.c_str(), this->point_num);
-  return {(float3 *)this->position, this->point_num};
+  return get_mutable_attribute(*this, ATTR_DOMAIN_POINT, ATTR_POSITION);
 }
 
 Span CurvesGeometry::offsets() const
@@ -724,8 +722,9 @@ Span CurvesGeometry::evaluated_tangents() const
       }
     });
 
-    /* Correct the first and last tangents of Bezier curves so that they align with the inner
-     * handles. This is a separate loop to avoid the cost when Bezier type curves are not used. */
+    /* Correct the first and last tangents of non-cyclic Bezier curves so that they align with the
+     * inner handles. This is a separate loop to avoid the cost when Bezier type curves are not
+     * used. */
     Vector bezier_indices;
     const IndexMask bezier_mask = this->indices_for_curve_type(CURVE_TYPE_BEZIER, bezier_indices);
     if (!bezier_mask.is_empty()) {
@@ -735,14 +734,20 @@ Span CurvesGeometry::evaluated_tangents() const
 
       threading::parallel_for(bezier_mask.index_range(), 1024, [&](IndexRange range) {
         for (const int curve_index : bezier_mask.slice(range)) {
+          if (cyclic[curve_index]) {
+            continue;
+          }
           const IndexRange points = this->points_for_curve(curve_index);
           const IndexRange evaluated_points = this->evaluated_points_for_curve(curve_index);
 
-          if (handles_right[points.first()] != positions[points.first()]) {
+          const float epsilon = 1e-6f;
+          if (!math::almost_equal_relative(
+                  handles_right[points.first()], positions[points.first()], epsilon)) {
             tangents[evaluated_points.first()] = math::normalize(handles_right[points.first()] -
                                                                  positions[points.first()]);
           }
-          if (handles_left[points.last()] != positions[points.last()]) {
+          if (!math::almost_equal_relative(
+                  handles_left[points.last()], positions[points.last()], epsilon)) {
             tangents[evaluated_points.last()] = math::normalize(positions[points.last()] -
                                                                 handles_left[points.last()]);
           }
@@ -943,6 +948,12 @@ void CurvesGeometry::ensure_evaluated_lengths() const
   this->runtime->length_cache_dirty = false;
 }
 
+void CurvesGeometry::ensure_can_interpolate_to_evaluated() const
+{
+  this->ensure_evaluated_offsets();
+  this->ensure_nurbs_basis_cache();
+}
+
 /** \} */
 
 /* -------------------------------------------------------------------- */
@@ -952,16 +963,15 @@ void CurvesGeometry::ensure_evaluated_lengths() const
 void CurvesGeometry::resize(const int points_num, const int curves_num)
 {
   if (points_num != this->point_num) {
-    CustomData_realloc(&this->point_data, points_num);
+    CustomData_realloc(&this->point_data, this->points_num(), points_num);
     this->point_num = points_num;
   }
   if (curves_num != this->curve_num) {
-    CustomData_realloc(&this->curve_data, curves_num);
+    CustomData_realloc(&this->curve_data, this->curves_num(), curves_num);
     this->curve_num = curves_num;
     this->curve_offsets = (int *)MEM_reallocN(this->curve_offsets, sizeof(int) * (curves_num + 1));
   }
   this->tag_topology_changed();
-  this->update_customdata_pointers();
 }
 
 void CurvesGeometry::tag_positions_changed()
@@ -1060,10 +1070,11 @@ void CurvesGeometry::transform(const float4x4 &matrix)
 
 static std::optional> curves_bounds(const CurvesGeometry &curves)
 {
-  Span positions = curves.positions();
-  if (curves.radius) {
-    Span radii{curves.radius, curves.points_num()};
-    return bounds::min_max_with_radii(positions, radii);
+  const Span positions = curves.positions();
+  const VArray radii = curves.attributes().lookup_or_default(
+      ATTR_RADIUS, ATTR_DOMAIN_POINT, 0.0f);
+  if (!(radii.is_single() && radii.get_internal_single() == 0.0f)) {
+    return bounds::min_max_with_radii(positions, radii.get_internal_span());
   }
   return bounds::min_max(positions);
 }
@@ -1079,31 +1090,6 @@ bool CurvesGeometry::bounds_min_max(float3 &min, float3 &max) const
   return true;
 }
 
-void CurvesGeometry::update_customdata_pointers()
-{
-  this->position = (float(*)[3])CustomData_get_layer_named(
-      &this->point_data, CD_PROP_FLOAT3, ATTR_POSITION.c_str());
-  this->radius = (float *)CustomData_get_layer_named(
-      &this->point_data, CD_PROP_FLOAT, ATTR_RADIUS.c_str());
-  this->curve_type = (int8_t *)CustomData_get_layer_named(
-      &this->point_data, CD_PROP_INT8, ATTR_CURVE_TYPE.c_str());
-}
-
-static void *ensure_customdata_layer(CustomData &custom_data,
-                                     const StringRefNull name,
-                                     const eCustomDataType data_type,
-                                     const int tot_elements)
-{
-  for (const int other_layer_i : IndexRange(custom_data.totlayer)) {
-    CustomDataLayer &new_layer = custom_data.layers[other_layer_i];
-    if (name == StringRef(new_layer.name)) {
-      return new_layer.data;
-    }
-  }
-  return CustomData_add_layer_named(
-      &custom_data, data_type, CD_DEFAULT, nullptr, tot_elements, name.c_str());
-}
-
 static void copy_between_buffers(const CPPType &type,
                                  const void *src_buffer,
                                  void *dst_buffer,
@@ -1193,61 +1179,50 @@ static CurvesGeometry copy_with_removed_points(const CurvesGeometry &curves,
   }
 
   CurvesGeometry new_curves{new_point_count, new_curve_count};
+  Vector point_attributes = bke::retrieve_attributes_for_transfer(
+      curves.attributes(), new_curves.attributes_for_write(), ATTR_DOMAIN_MASK_POINT);
+  Vector curve_attributes = bke::retrieve_attributes_for_transfer(
+      curves.attributes(), new_curves.attributes_for_write(), ATTR_DOMAIN_MASK_CURVE);
 
   threading::parallel_invoke(
+      256 < new_point_count * new_curve_count,
       /* Initialize curve offsets. */
       [&]() { new_curves.offsets_for_write().copy_from(new_curve_offsets); },
-      /* Copy over point attributes. */
       [&]() {
-        const CustomData &old_point_data = curves.point_data;
-        CustomData &new_point_data = new_curves.point_data;
-        for (const int layer_i : IndexRange(old_point_data.totlayer)) {
-          const CustomDataLayer &old_layer = old_point_data.layers[layer_i];
-          const eCustomDataType data_type = static_cast(old_layer.type);
-          const CPPType &type = *bke::custom_data_type_to_cpp_type(data_type);
-
-          void *dst_buffer = ensure_customdata_layer(
-              new_point_data, old_layer.name, data_type, new_point_count);
-
-          threading::parallel_for(
-              copy_point_ranges.index_range(), 128, [&](const IndexRange ranges_range) {
-                for (const int range_i : ranges_range) {
-                  const IndexRange src_range = copy_point_ranges[range_i];
-                  copy_between_buffers(type,
-                                       old_layer.data,
-                                       dst_buffer,
-                                       src_range,
-                                       {copy_point_range_dst_offsets[range_i], src_range.size()});
-                }
-              });
+        /* Copy over point attributes. */
+        for (bke::AttributeTransferData &attribute : point_attributes) {
+          threading::parallel_for(copy_point_ranges.index_range(), 128, [&](IndexRange range) {
+            for (const int range_i : range) {
+              const IndexRange src_range = copy_point_ranges[range_i];
+              copy_between_buffers(attribute.src.type(),
+                                   attribute.src.data(),
+                                   attribute.dst.span.data(),
+                                   src_range,
+                                   {copy_point_range_dst_offsets[range_i], src_range.size()});
+            }
+          });
         }
       },
-      /* Copy over curve attributes.
-       * In some cases points are just dissolved, so the the number of
-       * curves will be the same. That could be optimized in the future. */
       [&]() {
-        const CustomData &old_curve_data = curves.curve_data;
-        CustomData &new_curve_data = new_curves.curve_data;
-        for (const int layer_i : IndexRange(old_curve_data.totlayer)) {
-          const CustomDataLayer &old_layer = old_curve_data.layers[layer_i];
-          const eCustomDataType data_type = static_cast(old_layer.type);
-          const CPPType &type = *bke::custom_data_type_to_cpp_type(data_type);
-
-          void *dst_buffer = ensure_customdata_layer(
-              new_curve_data, old_layer.name, data_type, new_curve_count);
-
+        /* Copy over curve attributes.
+         * In some cases points are just dissolved, so the number of
+         * curves will be the same. That could be optimized in the future. */
+        for (bke::AttributeTransferData &attribute : curve_attributes) {
           if (new_curves.curves_num() == curves.curves_num()) {
-            type.copy_construct_n(old_layer.data, dst_buffer, new_curves.curves_num());
+            attribute.dst.span.copy_from(attribute.src);
           }
           else {
-            copy_with_map({type, old_layer.data, curves.curves_num()},
-                          new_curve_orig_indices,
-                          {type, dst_buffer, new_curves.curves_num()});
+            copy_with_map(attribute.src, new_curve_orig_indices, attribute.dst.span);
           }
         }
       });
 
-  new_curves.update_curve_types();
+  for (bke::AttributeTransferData &attribute : point_attributes) {
+    attribute.dst.finish();
+  }
+  for (bke::AttributeTransferData &attribute : curve_attributes) {
+    attribute.dst.finish();
+  }
 
   return new_curves;
 }
@@ -1285,8 +1260,13 @@ static CurvesGeometry copy_with_removed_curves(const CurvesGeometry &curves,
   }
 
   CurvesGeometry new_curves{new_tot_points, new_tot_curves};
+  Vector point_attributes = bke::retrieve_attributes_for_transfer(
+      curves.attributes(), new_curves.attributes_for_write(), ATTR_DOMAIN_MASK_POINT);
+  Vector curve_attributes = bke::retrieve_attributes_for_transfer(
+      curves.attributes(), new_curves.attributes_for_write(), ATTR_DOMAIN_MASK_CURVE);
 
   threading::parallel_invoke(
+      256 < new_tot_points * new_tot_curves,
       /* Initialize curve offsets. */
       [&]() {
         MutableSpan new_offsets = new_curves.offsets_for_write();
@@ -1313,56 +1293,41 @@ static CurvesGeometry copy_with_removed_curves(const CurvesGeometry &curves,
               }
             });
       },
-      /* Copy over point attributes. */
       [&]() {
-        const CustomData &old_point_data = curves.point_data;
-        CustomData &new_point_data = new_curves.point_data;
-        for (const int layer_i : IndexRange(old_point_data.totlayer)) {
-          const CustomDataLayer &old_layer = old_point_data.layers[layer_i];
-          const eCustomDataType data_type = static_cast(old_layer.type);
-          const CPPType &type = *bke::custom_data_type_to_cpp_type(data_type);
-
-          void *dst_buffer = ensure_customdata_layer(
-              new_point_data, old_layer.name, data_type, new_tot_points);
-
-          threading::parallel_for(
-              old_curve_ranges.index_range(), 128, [&](const IndexRange ranges_range) {
-                for (const int range_i : ranges_range) {
-                  copy_between_buffers(type,
-                                       old_layer.data,
-                                       dst_buffer,
-                                       old_point_ranges[range_i],
-                                       new_point_ranges[range_i]);
-                }
-              });
+        /* Copy over point attributes. */
+        for (bke::AttributeTransferData &attribute : point_attributes) {
+          threading::parallel_for(old_curve_ranges.index_range(), 128, [&](IndexRange range) {
+            for (const int range_i : range) {
+              copy_between_buffers(attribute.src.type(),
+                                   attribute.src.data(),
+                                   attribute.dst.span.data(),
+                                   old_point_ranges[range_i],
+                                   new_point_ranges[range_i]);
+            }
+          });
         }
       },
-      /* Copy over curve attributes. */
       [&]() {
-        const CustomData &old_curve_data = curves.curve_data;
-        CustomData &new_curve_data = new_curves.curve_data;
-        for (const int layer_i : IndexRange(old_curve_data.totlayer)) {
-          const CustomDataLayer &old_layer = old_curve_data.layers[layer_i];
-          const eCustomDataType data_type = static_cast(old_layer.type);
-          const CPPType &type = *bke::custom_data_type_to_cpp_type(data_type);
-
-          void *dst_buffer = ensure_customdata_layer(
-              new_curve_data, old_layer.name, data_type, new_tot_curves);
-
-          threading::parallel_for(
-              old_curve_ranges.index_range(), 128, [&](const IndexRange ranges_range) {
-                for (const int range_i : ranges_range) {
-                  copy_between_buffers(type,
-                                       old_layer.data,
-                                       dst_buffer,
-                                       old_curve_ranges[range_i],
-                                       new_curve_ranges[range_i]);
-                }
-              });
+        /* Copy over curve attributes. */
+        for (bke::AttributeTransferData &attribute : curve_attributes) {
+          threading::parallel_for(old_curve_ranges.index_range(), 128, [&](IndexRange range) {
+            for (const int range_i : range) {
+              copy_between_buffers(attribute.src.type(),
+                                   attribute.src.data(),
+                                   attribute.dst.span.data(),
+                                   old_curve_ranges[range_i],
+                                   new_curve_ranges[range_i]);
+            }
+          });
         }
       });
 
-  new_curves.update_curve_types();
+  for (bke::AttributeTransferData &attribute : point_attributes) {
+    attribute.dst.finish();
+  }
+  for (bke::AttributeTransferData &attribute : curve_attributes) {
+    attribute.dst.finish();
+  }
 
   return new_curves;
 }
@@ -1407,73 +1372,57 @@ static void reverse_swap_curve_point_data(const CurvesGeometry &curves,
         std::swap(a[end_index], b[i]);
         std::swap(b[end_index], a[i]);
       }
+      if (points.size() % 2) {
+        const int64_t middle_index = points.size() / 2;
+        std::swap(a[middle_index], b[middle_index]);
+      }
     }
   });
 }
 
-static bool layer_matches_name_and_type(const CustomDataLayer &layer,
-                                        const StringRef name,
-                                        const eCustomDataType type)
-{
-  if (layer.type != type) {
-    return false;
-  }
-  return layer.name == name;
-}
-
 void CurvesGeometry::reverse_curves(const IndexMask curves_to_reverse)
 {
-  CustomData_duplicate_referenced_layers(&this->point_data, this->points_num());
+  Set bezier_handle_names{{ATTR_HANDLE_POSITION_LEFT,
+                                      ATTR_HANDLE_POSITION_RIGHT,
+                                      ATTR_HANDLE_TYPE_LEFT,
+                                      ATTR_HANDLE_TYPE_RIGHT}};
 
-  /* Collect the Bezier handle attributes while iterating through the point custom data layers;
-   * they need special treatment later. */
-  MutableSpan positions_left;
-  MutableSpan positions_right;
-  MutableSpan types_left;
-  MutableSpan types_right;
+  MutableAttributeAccessor attributes = this->attributes_for_write();
 
-  for (const int layer_i : IndexRange(this->point_data.totlayer)) {
-    CustomDataLayer &layer = this->point_data.layers[layer_i];
-
-    if (positions_left.is_empty() &&
-        layer_matches_name_and_type(layer, ATTR_HANDLE_POSITION_LEFT, CD_PROP_FLOAT3)) {
-      positions_left = {static_cast(layer.data), this->points_num()};
-      continue;
-    }
-    if (positions_right.is_empty() &&
-        layer_matches_name_and_type(layer, ATTR_HANDLE_POSITION_RIGHT, CD_PROP_FLOAT3)) {
-      positions_right = {static_cast(layer.data), this->points_num()};
-      continue;
+  attributes.for_all([&](const AttributeIDRef &id, AttributeMetaData meta_data) {
+    if (meta_data.domain != ATTR_DOMAIN_POINT) {
+      return true;
     }
-    if (types_left.is_empty() &&
-        layer_matches_name_and_type(layer, ATTR_HANDLE_TYPE_LEFT, CD_PROP_INT8)) {
-      types_left = {static_cast(layer.data), this->points_num()};
-      continue;
-    }
-    if (types_right.is_empty() &&
-        layer_matches_name_and_type(layer, ATTR_HANDLE_TYPE_RIGHT, CD_PROP_INT8)) {
-      types_right = {static_cast(layer.data), this->points_num()};
-      continue;
+    if (id.is_named() && bezier_handle_names.contains(id.name())) {
+      return true;
     }
 
-    const eCustomDataType data_type = static_cast(layer.type);
-    attribute_math::convert_to_static_type(data_type, [&](auto dummy) {
+    GSpanAttributeWriter attribute = attributes.lookup_for_write_span(id);
+    attribute_math::convert_to_static_type(attribute.span.type(), [&](auto dummy) {
       using T = decltype(dummy);
-      reverse_curve_point_data(
-          *this, curves_to_reverse, {static_cast(layer.data), this->points_num()});
+      reverse_curve_point_data(*this, curves_to_reverse, attribute.span.typed());
     });
-  }
+    attribute.finish();
+    return true;
+  });
 
   /* In order to maintain the shape of Bezier curves, handle attributes must reverse, but also the
    * values for the left and right must swap. Use a utility to swap and reverse at the same time,
    * to avoid loading the attribute twice. Generally we can expect the right layer to exist when
    * the left does, but there's no need to count on it, so check for both attributes. */
 
-  if (!positions_left.is_empty() && !positions_right.is_empty()) {
-    reverse_swap_curve_point_data(*this, curves_to_reverse, positions_left, positions_right);
+  if (attributes.contains(ATTR_HANDLE_POSITION_LEFT) &&
+      attributes.contains(ATTR_HANDLE_POSITION_RIGHT)) {
+    reverse_swap_curve_point_data(*this,
+                                  curves_to_reverse,
+                                  this->handle_positions_left_for_write(),
+                                  this->handle_positions_right_for_write());
   }
-  if (!types_left.is_empty() && !types_right.is_empty()) {
-    reverse_swap_curve_point_data(*this, curves_to_reverse, types_left, types_right);
+  if (attributes.contains(ATTR_HANDLE_TYPE_LEFT) && attributes.contains(ATTR_HANDLE_TYPE_RIGHT)) {
+    reverse_swap_curve_point_data(*this,
+                                  curves_to_reverse,
+                                  this->handle_types_left_for_write(),
+                                  this->handle_types_right_for_write());
   }
 
   this->tag_topology_changed();
@@ -1481,23 +1430,21 @@ void CurvesGeometry::reverse_curves(const IndexMask curves_to_reverse)
 
 void CurvesGeometry::remove_attributes_based_on_types()
 {
-  const int points_num = this->points_num();
-  const int curves_num = this->curves_num();
+  MutableAttributeAccessor attributes = this->attributes_for_write();
   if (!this->has_curve_with_type(CURVE_TYPE_BEZIER)) {
-    CustomData_free_layer_named(&this->point_data, ATTR_HANDLE_TYPE_LEFT.c_str(), points_num);
-    CustomData_free_layer_named(&this->point_data, ATTR_HANDLE_TYPE_RIGHT.c_str(), points_num);
-    CustomData_free_layer_named(&this->point_data, ATTR_HANDLE_POSITION_LEFT.c_str(), points_num);
-    CustomData_free_layer_named(&this->point_data, ATTR_HANDLE_POSITION_RIGHT.c_str(), points_num);
+    attributes.remove(ATTR_HANDLE_TYPE_LEFT);
+    attributes.remove(ATTR_HANDLE_TYPE_RIGHT);
+    attributes.remove(ATTR_HANDLE_POSITION_LEFT);
+    attributes.remove(ATTR_HANDLE_POSITION_RIGHT);
   }
   if (!this->has_curve_with_type(CURVE_TYPE_NURBS)) {
-    CustomData_free_layer_named(&this->point_data, ATTR_NURBS_WEIGHT.c_str(), points_num);
-    CustomData_free_layer_named(&this->curve_data, ATTR_NURBS_ORDER.c_str(), curves_num);
-    CustomData_free_layer_named(&this->curve_data, ATTR_NURBS_KNOTS_MODE.c_str(), curves_num);
+    attributes.remove(ATTR_NURBS_WEIGHT);
+    attributes.remove(ATTR_NURBS_ORDER);
+    attributes.remove(ATTR_NURBS_KNOTS_MODE);
   }
   if (!this->has_curve_with_type({CURVE_TYPE_BEZIER, CURVE_TYPE_CATMULL_ROM, CURVE_TYPE_NURBS})) {
-    CustomData_free_layer_named(&this->curve_data, ATTR_RESOLUTION.c_str(), curves_num);
+    attributes.remove(ATTR_RESOLUTION);
   }
-  this->update_customdata_pointers();
 }
 
 /** \} */
@@ -1519,12 +1466,15 @@ static void adapt_curve_domain_point_to_curve_impl(const CurvesGeometry &curves,
                                                    MutableSpan r_values)
 {
   attribute_math::DefaultMixer mixer(r_values);
-  for (const int i_curve : IndexRange(curves.curves_num())) {
-    for (const int i_point : curves.points_for_curve(i_curve)) {
-      mixer.mix_in(i_curve, old_values[i_point]);
+
+  threading::parallel_for(curves.curves_range(), 128, [&](const IndexRange range) {
+    for (const int i_curve : range) {
+      for (const int i_point : curves.points_for_curve(i_curve)) {
+        mixer.mix_in(i_curve, old_values[i_point]);
+      }
     }
-  }
-  mixer.finalize();
+    mixer.finalize(range);
+  });
 }
 
 /**
diff --git a/source/blender/blenkernel/intern/curves_utils.cc b/source/blender/blenkernel/intern/curves_utils.cc
index f7db60ee588..f5a69a995a3 100644
--- a/source/blender/blenkernel/intern/curves_utils.cc
+++ b/source/blender/blenkernel/intern/curves_utils.cc
@@ -84,6 +84,33 @@ void fill_points(const CurvesGeometry &curves,
   });
 }
 
+void fill_points(const CurvesGeometry &curves,
+                 Span curve_ranges,
+                 GPointer value,
+                 GMutableSpan dst)
+{
+  BLI_assert(*value.type() == dst.type());
+  const CPPType &type = dst.type();
+  threading::parallel_for(curve_ranges.index_range(), 512, [&](IndexRange range) {
+    for (const IndexRange range : curve_ranges.slice(range)) {
+      const IndexRange points = curves.points_for_curves(range);
+      type.fill_assign_n(value.get(), dst.slice(points).data(), points.size());
+    }
+  });
+}
+
+bke::CurvesGeometry copy_only_curve_domain(const bke::CurvesGeometry &src_curves)
+{
+  bke::CurvesGeometry dst_curves(0, src_curves.curves_num());
+  CustomData_copy(&src_curves.curve_data,
+                  &dst_curves.curve_data,
+                  CD_MASK_ALL,
+                  CD_DUPLICATE,
+                  src_curves.curves_num());
+  dst_curves.runtime->type_counts = src_curves.runtime->type_counts;
+  return dst_curves;
+}
+
 IndexMask indices_for_type(const VArray &types,
                            const std::array &type_counts,
                            const CurveType type,
diff --git a/source/blender/blenkernel/intern/customdata.cc b/source/blender/blenkernel/intern/customdata.cc
index 277218033e9..0589e1ef8c7 100644
--- a/source/blender/blenkernel/intern/customdata.cc
+++ b/source/blender/blenkernel/intern/customdata.cc
@@ -26,6 +26,7 @@
 #include "BLI_math_vector.hh"
 #include "BLI_mempool.h"
 #include "BLI_path_util.h"
+#include "BLI_set.hh"
 #include "BLI_span.hh"
 #include "BLI_string.h"
 #include "BLI_string_ref.hh"
@@ -58,6 +59,7 @@
 #include "data_transfer_intern.h"
 
 using blender::IndexRange;
+using blender::Set;
 using blender::Span;
 using blender::StringRef;
 using blender::Vector;
@@ -152,9 +154,15 @@ struct LayerTypeInfo {
   void (*swap)(void *data, const int *corner_indices);
 
   /**
-   * a function to set a layer's data to default values. if null, the
-   * default is assumed to be all zeros */
-  void (*set_default)(void *data, int count);
+   * Set values to the type's default. If undefined, the default is assumed to be zeroes.
+   * Memory pointed to by #data is expected to be uninitialized.
+   */
+  void (*set_default_value)(void *data, int count);
+  /**
+   * Construct and fill a valid value for the type. Necessary for non-trivial types.
+   * Memory pointed to by #data is expected to be uninitialized.
+   */
+  void (*construct)(void *data, int count);
 
   /** A function used by mesh validating code, must ensures passed item has valid data. */
   cd_validate validate;
@@ -165,7 +173,7 @@ struct LayerTypeInfo {
   void (*initminmax)(void *min, void *max);
   void (*add)(void *data1, const void *data2);
   void (*dominmax)(const void *data1, void *min, void *max);
-  void (*copyvalue)(const void *source, void *dest, const int mixmode, const float mixfactor);
+  void (*copyvalue)(const void *source, void *dest, int mixmode, const float mixfactor);
 
   /** a function to read data from a cdf file */
   bool (*read)(CDataFile *cdf, void *data, int count);
@@ -187,7 +195,7 @@ struct LayerTypeInfo {
 /** \name Callbacks for (#MDeformVert, #CD_MDEFORMVERT)
  * \{ */
 
-static void layerCopy_mdeformvert(const void *source, void *dest, int count)
+static void layerCopy_mdeformvert(const void *source, void *dest, const int count)
 {
   int i, size = sizeof(MDeformVert);
 
@@ -209,7 +217,7 @@ static void layerCopy_mdeformvert(const void *source, void *dest, int count)
   }
 }
 
-static void layerFree_mdeformvert(void *data, int count, int size)
+static void layerFree_mdeformvert(void *data, const int count, const int size)
 {
   for (int i = 0; i < count; i++) {
     MDeformVert *dvert = static_cast(POINTER_OFFSET(data, i * size));
@@ -222,38 +230,10 @@ static void layerFree_mdeformvert(void *data, int count, int size)
   }
 }
 
-/* copy just zeros in this case */
-static void layerCopy_bmesh_elem_py_ptr(const void *UNUSED(source), void *dest, int count)
-{
-  const int size = sizeof(void *);
-
-  for (int i = 0; i < count; i++) {
-    void **ptr = (void **)POINTER_OFFSET(dest, i * size);
-    *ptr = nullptr;
-  }
-}
-
-#ifndef WITH_PYTHON
-void bpy_bm_generic_invalidate(struct BPy_BMGeneric *UNUSED(self))
-{
-  /* dummy */
-}
-#endif
-
-static void layerFree_bmesh_elem_py_ptr(void *data, int count, int size)
-{
-  for (int i = 0; i < count; i++) {
-    void **ptr = (void **)POINTER_OFFSET(data, i * size);
-    if (*ptr) {
-      bpy_bm_generic_invalidate(static_cast(*ptr));
-    }
-  }
-}
-
 static void layerInterp_mdeformvert(const void **sources,
                                     const float *weights,
                                     const float *UNUSED(sub_weights),
-                                    int count,
+                                    const int count,
                                     void *dest)
 {
   /* a single linked list of MDeformWeight's
@@ -338,6 +318,11 @@ static void layerInterp_mdeformvert(const void **sources,
   }
 }
 
+static void layerConstruct_mdeformvert(void *data, const int count)
+{
+  memset(data, 0, sizeof(MDeformVert) * count);
+}
+
 /** \} */
 
 /* -------------------------------------------------------------------- */
@@ -347,7 +332,7 @@ static void layerInterp_mdeformvert(const void **sources,
 static void layerInterp_normal(const void **sources,
                                const float *weights,
                                const float *UNUSED(sub_weights),
-                               int count,
+                               const int count,
                                void *dest)
 {
   /* NOTE: This is linear interpolation, which is not optimal for vectors.
@@ -355,8 +340,8 @@ static void layerInterp_normal(const void **sources,
    * so for now it will do... */
   float no[3] = {0.0f};
 
-  while (count--) {
-    madd_v3_v3fl(no, (const float *)sources[count], weights[count]);
+  for (const int i : IndexRange(count)) {
+    madd_v3_v3fl(no, (const float *)sources[i], weights[i]);
   }
 
   /* Weighted sum of normalized vectors will **not** be normalized, even if weights are. */
@@ -406,7 +391,7 @@ static void layerCopyValue_normal(const void *source,
 /** \name Callbacks for (#MTFace, #CD_MTFACE)
  * \{ */
 
-static void layerCopy_tface(const void *source, void *dest, int count)
+static void layerCopy_tface(const void *source, void *dest, const int count)
 {
   const MTFace *source_tf = (const MTFace *)source;
   MTFace *dest_tf = (MTFace *)dest;
@@ -415,8 +400,11 @@ static void layerCopy_tface(const void *source, void *dest, int count)
   }
 }
 
-static void layerInterp_tface(
-    const void **sources, const float *weights, const float *sub_weights, int count, void *dest)
+static void layerInterp_tface(const void **sources,
+                              const float *weights,
+                              const float *sub_weights,
+                              const int count,
+                              void *dest)
 {
   MTFace *tf = static_cast(dest);
   float uv[4][2] = {{0.0f}};
@@ -456,7 +444,7 @@ static void layerSwap_tface(void *data, const int *corner_indices)
   memcpy(tf->uv, uv, sizeof(tf->uv));
 }
 
-static void layerDefault_tface(void *data, int count)
+static void layerDefault_tface(void *data, const int count)
 {
   static MTFace default_tf = {{{0, 0}, {1, 0}, {1, 1}, {0, 1}}};
   MTFace *tf = (MTFace *)data;
@@ -477,7 +465,7 @@ static int layerMaxNum_tface()
 /** \name Callbacks for (#MFloatProperty, #CD_PROP_FLOAT)
  * \{ */
 
-static void layerCopy_propFloat(const void *source, void *dest, int count)
+static void layerCopy_propFloat(const void *source, void *dest, const int count)
 {
   memcpy(dest, source, sizeof(MFloatProperty) * count);
 }
@@ -485,7 +473,7 @@ static void layerCopy_propFloat(const void *source, void *dest, int count)
 static void layerInterp_propFloat(const void **sources,
                                   const float *weights,
                                   const float *UNUSED(sub_weights),
-                                  int count,
+                                  const int count,
                                   void *dest)
 {
   float result = 0.0f;
@@ -520,15 +508,10 @@ static bool layerValidate_propFloat(void *data, const uint totitems, const bool
 /** \name Callbacks for (#MIntProperty, #CD_PROP_INT32)
  * \{ */
 
-static void layerCopy_propInt(const void *source, void *dest, int count)
-{
-  memcpy(dest, source, sizeof(MIntProperty) * count);
-}
-
 static void layerInterp_propInt(const void **sources,
                                 const float *weights,
                                 const float *UNUSED(sub_weights),
-                                int count,
+                                const int count,
                                 void *dest)
 {
   float result = 0.0f;
@@ -547,7 +530,7 @@ static void layerInterp_propInt(const void **sources,
 /** \name Callbacks for (#MStringProperty, #CD_PROP_STRING)
  * \{ */
 
-static void layerCopy_propString(const void *source, void *dest, int count)
+static void layerCopy_propString(const void *source, void *dest, const int count)
 {
   memcpy(dest, source, sizeof(MStringProperty) * count);
 }
@@ -558,7 +541,7 @@ static void layerCopy_propString(const void *source, void *dest, int count)
 /** \name Callbacks for (#OrigSpaceFace, #CD_ORIGSPACE)
  * \{ */
 
-static void layerCopy_origspace_face(const void *source, void *dest, int count)
+static void layerCopy_origspace_face(const void *source, void *dest, const int count)
 {
   const OrigSpaceFace *source_tf = (const OrigSpaceFace *)source;
   OrigSpaceFace *dest_tf = (OrigSpaceFace *)dest;
@@ -568,8 +551,11 @@ static void layerCopy_origspace_face(const void *source, void *dest, int count)
   }
 }
 
-static void layerInterp_origspace_face(
-    const void **sources, const float *weights, const float *sub_weights, int count, void *dest)
+static void layerInterp_origspace_face(const void **sources,
+                                       const float *weights,
+                                       const float *sub_weights,
+                                       const int count,
+                                       void *dest)
 {
   OrigSpaceFace *osf = static_cast(dest);
   float uv[4][2] = {{0.0f}};
@@ -606,7 +592,7 @@ static void layerSwap_origspace_face(void *data, const int *corner_indices)
   memcpy(osf->uv, uv, sizeof(osf->uv));
 }
 
-static void layerDefault_origspace_face(void *data, int count)
+static void layerDefault_origspace_face(void *data, const int count)
 {
   static OrigSpaceFace default_osf = {{{0, 0}, {1, 0}, {1, 1}, {0, 1}}};
   OrigSpaceFace *osf = (OrigSpaceFace *)data;
@@ -652,7 +638,7 @@ static void layerSwap_mdisps(void *data, const int *ci)
   }
 }
 
-static void layerCopy_mdisps(const void *source, void *dest, int count)
+static void layerCopy_mdisps(const void *source, void *dest, const int count)
 {
   const MDisps *s = static_cast(source);
   MDisps *d = static_cast(dest);
@@ -673,7 +659,7 @@ static void layerCopy_mdisps(const void *source, void *dest, int count)
   }
 }
 
-static void layerFree_mdisps(void *data, int count, int UNUSED(size))
+static void layerFree_mdisps(void *data, const int count, const int UNUSED(size))
 {
   MDisps *d = static_cast(data);
 
@@ -691,7 +677,12 @@ static void layerFree_mdisps(void *data, int count, int UNUSED(size))
   }
 }
 
-static bool layerRead_mdisps(CDataFile *cdf, void *data, int count)
+static void layerConstruct_mdisps(void *data, const int count)
+{
+  memset(data, 0, sizeof(MDisps) * count);
+}
+
+static bool layerRead_mdisps(CDataFile *cdf, void *data, const int count)
 {
   MDisps *d = static_cast(data);
 
@@ -709,7 +700,7 @@ static bool layerRead_mdisps(CDataFile *cdf, void *data, int count)
   return true;
 }
 
-static bool layerWrite_mdisps(CDataFile *cdf, const void *data, int count)
+static bool layerWrite_mdisps(CDataFile *cdf, const void *data, const int count)
 {
   const MDisps *d = static_cast(data);
 
@@ -723,7 +714,7 @@ static bool layerWrite_mdisps(CDataFile *cdf, const void *data, int count)
   return true;
 }
 
-static size_t layerFilesize_mdisps(CDataFile *UNUSED(cdf), const void *data, int count)
+static size_t layerFilesize_mdisps(CDataFile *UNUSED(cdf), const void *data, const int count)
 {
   const MDisps *d = static_cast(data);
   size_t size = 0;
@@ -737,6 +728,40 @@ static size_t layerFilesize_mdisps(CDataFile *UNUSED(cdf), const void *data, int
 
 /** \} */
 
+/* -------------------------------------------------------------------- */
+/** \name Callbacks for (#CD_BM_ELEM_PYPTR)
+ * \{ */
+
+/* copy just zeros in this case */
+static void layerCopy_bmesh_elem_py_ptr(const void *UNUSED(source), void *dest, const int count)
+{
+  const int size = sizeof(void *);
+
+  for (int i = 0; i < count; i++) {
+    void **ptr = (void **)POINTER_OFFSET(dest, i * size);
+    *ptr = nullptr;
+  }
+}
+
+#ifndef WITH_PYTHON
+void bpy_bm_generic_invalidate(struct BPy_BMGeneric *UNUSED(self))
+{
+  /* dummy */
+}
+#endif
+
+static void layerFree_bmesh_elem_py_ptr(void *data, const int count, const int size)
+{
+  for (int i = 0; i < count; i++) {
+    void **ptr = (void **)POINTER_OFFSET(data, i * size);
+    if (*ptr) {
+      bpy_bm_generic_invalidate(static_cast(*ptr));
+    }
+  }
+}
+
+/** \} */
+
 /* -------------------------------------------------------------------- */
 /** \name Callbacks for (`float`, #CD_PAINT_MASK)
  * \{ */
@@ -762,7 +787,7 @@ static void layerInterp_paint_mask(const void **sources,
 /** \name Callbacks for (#GridPaintMask, #CD_GRID_PAINT_MASK)
  * \{ */
 
-static void layerCopy_grid_paint_mask(const void *source, void *dest, int count)
+static void layerCopy_grid_paint_mask(const void *source, void *dest, const int count)
 {
   const GridPaintMask *s = static_cast(source);
   GridPaintMask *d = static_cast(dest);
@@ -779,7 +804,7 @@ static void layerCopy_grid_paint_mask(const void *source, void *dest, int count)
   }
 }
 
-static void layerFree_grid_paint_mask(void *data, int count, int UNUSED(size))
+static void layerFree_grid_paint_mask(void *data, const int count, const int UNUSED(size))
 {
   GridPaintMask *gpm = static_cast(data);
 
@@ -789,6 +814,11 @@ static void layerFree_grid_paint_mask(void *data, int count, int UNUSED(size))
   }
 }
 
+static void layerConstruct_grid_paint_mask(void *data, const int count)
+{
+  memset(data, 0, sizeof(GridPaintMask) * count);
+}
+
 /** \} */
 
 /* -------------------------------------------------------------------- */
@@ -867,7 +897,7 @@ static bool layerEqual_mloopcol(const void *data1, const void *data2)
   return r * r + g * g + b * b + a * a < 0.001f;
 }
 
-static void layerMultiply_mloopcol(void *data, float fac)
+static void layerMultiply_mloopcol(void *data, const float fac)
 {
   MLoopCol *m = static_cast(data);
 
@@ -936,7 +966,7 @@ static void layerInitMinMax_mloopcol(void *vmin, void *vmax)
   max->a = 0;
 }
 
-static void layerDefault_mloopcol(void *data, int count)
+static void layerDefault_mloopcol(void *data, const int count)
 {
   MLoopCol default_mloopcol = {255, 255, 255, 255};
   MLoopCol *mlcol = (MLoopCol *)data;
@@ -978,11 +1008,6 @@ static void layerInterp_mloopcol(const void **sources,
   mc->a = round_fl_to_uchar_clamp(col.a);
 }
 
-static int layerMaxNum_mloopcol()
-{
-  return MAX_MCOL;
-}
-
 /** \} */
 
 /* -------------------------------------------------------------------- */
@@ -1016,7 +1041,7 @@ static bool layerEqual_mloopuv(const void *data1, const void *data2)
   return len_squared_v2v2(luv1->uv, luv2->uv) < 0.00001f;
 }
 
-static void layerMultiply_mloopuv(void *data, float fac)
+static void layerMultiply_mloopuv(void *data, const float fac)
 {
   MLoopUV *luv = static_cast(data);
 
@@ -1110,7 +1135,7 @@ static bool layerEqual_mloop_origspace(const void *data1, const void *data2)
   return len_squared_v2v2(luv1->uv, luv2->uv) < 0.00001f;
 }
 
-static void layerMultiply_mloop_origspace(void *data, float fac)
+static void layerMultiply_mloop_origspace(void *data, const float fac)
 {
   OrigSpaceLoop *luv = static_cast(data);
 
@@ -1162,8 +1187,11 @@ static void layerInterp_mloop_origspace(const void **sources,
 }
 /* --- end copy */
 
-static void layerInterp_mcol(
-    const void **sources, const float *weights, const float *sub_weights, int count, void *dest)
+static void layerInterp_mcol(const void **sources,
+                             const float *weights,
+                             const float *sub_weights,
+                             const int count,
+                             void *dest)
 {
   MCol *mc = static_cast(dest);
   struct {
@@ -1222,7 +1250,7 @@ static void layerSwap_mcol(void *data, const int *corner_indices)
   memcpy(mcol, col, sizeof(col));
 }
 
-static void layerDefault_mcol(void *data, int count)
+static void layerDefault_mcol(void *data, const int count)
 {
   static MCol default_mcol = {255, 255, 255, 255};
   MCol *mcol = (MCol *)data;
@@ -1232,7 +1260,7 @@ static void layerDefault_mcol(void *data, int count)
   }
 }
 
-static void layerDefault_origindex(void *data, int count)
+static void layerDefault_origindex(void *data, const int count)
 {
   copy_vn_i((int *)data, count, ORIGINDEX_NONE);
 }
@@ -1290,7 +1318,7 @@ static void layerInterp_shapekey(const void **sources,
 /** \name Callbacks for (#MVertSkin, #CD_MVERT_SKIN)
  * \{ */
 
-static void layerDefault_mvert_skin(void *data, int count)
+static void layerDefault_mvert_skin(void *data, const int count)
 {
   MVertSkin *vs = static_cast(data);
 
@@ -1300,7 +1328,7 @@ static void layerDefault_mvert_skin(void *data, int count)
   }
 }
 
-static void layerCopy_mvert_skin(const void *source, void *dest, int count)
+static void layerCopy_mvert_skin(const void *source, void *dest, const int count)
 {
   memcpy(dest, source, sizeof(MVertSkin) * count);
 }
@@ -1352,7 +1380,7 @@ static void layerSwap_flnor(void *data, const int *corner_indices)
 /** \name Callbacks for (`int`, #CD_FACEMAP)
  * \{ */
 
-static void layerDefault_fmap(void *data, int count)
+static void layerDefault_fmap(void *data, const int count)
 {
   int *fmap_num = (int *)data;
   for (int i = 0; i < count; i++) {
@@ -1428,7 +1456,7 @@ static bool layerEqual_propcol(const void *data1, const void *data2)
   return tot < 0.001f;
 }
 
-static void layerMultiply_propcol(void *data, float fac)
+static void layerMultiply_propcol(void *data, const float fac)
 {
   MPropCol *m = static_cast(data);
   mul_v4_fl(m->color, fac);
@@ -1458,7 +1486,7 @@ static void layerInitMinMax_propcol(void *vmin, void *vmax)
   copy_v4_fl(max->color, FLT_MIN);
 }
 
-static void layerDefault_propcol(void *data, int count)
+static void layerDefault_propcol(void *data, const int count)
 {
   /* Default to white, full alpha. */
   MPropCol default_propcol = {{1.0f, 1.0f, 1.0f, 1.0f}};
@@ -1484,11 +1512,6 @@ static void layerInterp_propcol(const void **sources,
   copy_v4_v4(mc->color, col);
 }
 
-static int layerMaxNum_propcol()
-{
-  return MAX_MCOL;
-}
-
 /** \} */
 
 /* -------------------------------------------------------------------- */
@@ -1510,7 +1533,7 @@ static void layerInterp_propfloat3(const void **sources,
   copy_v3_v3((float *)dest, &result.x);
 }
 
-static void layerMultiply_propfloat3(void *data, float fac)
+static void layerMultiply_propfloat3(void *data, const float fac)
 {
   vec3f *vec = static_cast(data);
   vec->x *= fac;
@@ -1563,7 +1586,7 @@ static void layerInterp_propfloat2(const void **sources,
   copy_v2_v2((float *)dest, &result.x);
 }
 
-static void layerMultiply_propfloat2(void *data, float fac)
+static void layerMultiply_propfloat2(void *data, const float fac)
 {
   vec2f *vec = static_cast(data);
   vec->x *= fac;
@@ -1628,30 +1651,23 @@ static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
      layerFree_mdeformvert,
      layerInterp_mdeformvert,
      nullptr,
-     nullptr},
+     nullptr,
+     layerConstruct_mdeformvert},
     /* 3: CD_MEDGE */
     {sizeof(MEdge), "MEdge", 1, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr},
     /* 4: CD_MFACE */
     {sizeof(MFace), "MFace", 1, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr},
     /* 5: CD_MTFACE */
-    {sizeof(MTFace),    "MTFace",         1,
-     N_("UVMap"),       layerCopy_tface,  nullptr,
-     layerInterp_tface, layerSwap_tface,  layerDefault_tface,
-     nullptr,           nullptr,          nullptr,
-     nullptr,           nullptr,          nullptr,
-     nullptr,           nullptr,          nullptr,
-     nullptr,           layerMaxNum_tface},
-    /* 6: CD_MCOL */
-    /* 4 MCol structs per face */
-    {sizeof(MCol[4]),
-     "MCol",
-     4,
-     N_("Col"),
+    {sizeof(MTFace),
+     "MTFace",
+     1,
+     N_("UVMap"),
+     layerCopy_tface,
      nullptr,
+     layerInterp_tface,
+     layerSwap_tface,
      nullptr,
-     layerInterp_mcol,
-     layerSwap_mcol,
-     layerDefault_mcol,
+     layerDefault_tface,
      nullptr,
      nullptr,
      nullptr,
@@ -1662,7 +1678,16 @@ static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
      nullptr,
      nullptr,
      nullptr,
-     layerMaxNum_mloopcol},
+     layerMaxNum_tface},
+    /* 6: CD_MCOL */
+    /* 4 MCol structs per face */
+    {sizeof(MCol[4]),  "MCol",         4,
+     N_("Col"),        nullptr,        nullptr,
+     layerInterp_mcol, layerSwap_mcol, layerDefault_mcol,
+     nullptr,          nullptr,        nullptr,
+     nullptr,          nullptr,        nullptr,
+     nullptr,          nullptr,        nullptr,
+     nullptr,          nullptr,        nullptr},
     /* 7: CD_ORIGINDEX */
     {sizeof(int), "", 0, nullptr, nullptr, nullptr, nullptr, nullptr, layerDefault_origindex},
     /* 8: CD_NORMAL */
@@ -1682,6 +1707,7 @@ static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
      nullptr,
      nullptr,
      nullptr,
+     nullptr,
      layerCopyValue_normal},
     /* 9: CD_FACEMAP */
     {sizeof(int), "", 0, nullptr, nullptr, nullptr, nullptr, nullptr, layerDefault_fmap, nullptr},
@@ -1695,13 +1721,14 @@ static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
      layerInterp_propFloat,
      nullptr,
      nullptr,
+     nullptr,
      layerValidate_propFloat},
     /* 11: CD_PROP_INT32 */
     {sizeof(MIntProperty),
      "MIntProperty",
      1,
      N_("Int"),
-     layerCopy_propInt,
+     nullptr,
      nullptr,
      layerInterp_propInt,
      nullptr},
@@ -1740,6 +1767,7 @@ static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
      layerInterp_mloopuv,
      nullptr,
      nullptr,
+     nullptr,
      layerValidate_mloopuv,
      layerEqual_mloopuv,
      layerMultiply_mloopuv,
@@ -1762,6 +1790,7 @@ static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
      nullptr,
      layerDefault_mloopcol,
      nullptr,
+     nullptr,
      layerEqual_mloopcol,
      layerMultiply_mloopcol,
      layerInitMinMax_mloopcol,
@@ -1771,7 +1800,7 @@ static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
      nullptr,
      nullptr,
      nullptr,
-     layerMaxNum_mloopcol},
+     nullptr},
     /* 18: CD_TANGENT */
     {sizeof(float[4][4]), "", 0, N_("Tangent"), nullptr, nullptr, nullptr, nullptr, nullptr},
     /* 19: CD_MDISPS */
@@ -1784,6 +1813,7 @@ static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
      nullptr,
      layerSwap_mdisps,
      nullptr,
+     layerConstruct_mdisps,
      nullptr,
      nullptr,
      nullptr,
@@ -1837,7 +1867,7 @@ static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
     /* 28: CD_SHAPEKEY */
     {sizeof(float[3]), "", 0, N_("ShapeKey"), nullptr, nullptr, layerInterp_shapekey},
     /* 29: CD_BWEIGHT */
-    {sizeof(float), "", 0, N_("BevelWeight"), nullptr, nullptr, layerInterp_bweight},
+    {sizeof(MFloatProperty), "MFloatProperty", 1, nullptr, nullptr, nullptr, layerInterp_bweight},
     /* 30: CD_CREASE */
     /* NOTE: we do not interpolate crease data as it should be either inherited for subdivided
      * edges, or for vertex creases, only present on the original vertex. */
@@ -1853,6 +1883,7 @@ static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
      nullptr,
      nullptr,
      nullptr,
+     nullptr,
      layerEqual_mloop_origspace,
      layerMultiply_mloop_origspace,
      layerInitMinMax_mloop_origspace,
@@ -1870,6 +1901,7 @@ static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
      nullptr,
      layerDefault_mloopcol,
      nullptr,
+     nullptr,
      layerEqual_mloopcol,
      layerMultiply_mloopcol,
      layerInitMinMax_mloopcol,
@@ -1897,7 +1929,8 @@ static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
      layerFree_grid_paint_mask,
      nullptr,
      nullptr,
-     nullptr},
+     nullptr,
+     layerConstruct_grid_paint_mask},
     /* 36: CD_MVERT_SKIN */
     {sizeof(MVertSkin),
      "MVertSkin",
@@ -1955,6 +1988,7 @@ static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
      nullptr,
      layerDefault_propcol,
      nullptr,
+     nullptr,
      layerEqual_propcol,
      layerMultiply_propcol,
      layerInitMinMax_propcol,
@@ -1964,7 +1998,7 @@ static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
      nullptr,
      nullptr,
      nullptr,
-     layerMaxNum_propcol},
+     nullptr},
     /* 48: CD_PROP_FLOAT3 */
     {sizeof(float[3]),
      "vec3f",
@@ -1975,6 +2009,7 @@ static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
      layerInterp_propfloat3,
      nullptr,
      nullptr,
+     nullptr,
      layerValidate_propfloat3,
      nullptr,
      layerMultiply_propfloat3,
@@ -1990,6 +2025,7 @@ static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
      layerInterp_propfloat2,
      nullptr,
      nullptr,
+     nullptr,
      layerValidate_propfloat2,
      nullptr,
      layerMultiply_propfloat2,
@@ -2072,23 +2108,23 @@ static const char *LAYERTYPENAMES[CD_NUMTYPES] = {
 };
 
 const CustomData_MeshMasks CD_MASK_BAREMESH = {
-    /* vmask */ CD_MASK_MVERT | CD_MASK_BWEIGHT,
-    /* emask */ CD_MASK_MEDGE | CD_MASK_BWEIGHT,
+    /* vmask */ CD_MASK_MVERT,
+    /* emask */ CD_MASK_MEDGE,
     /* fmask */ 0,
     /* pmask */ CD_MASK_MPOLY | CD_MASK_FACEMAP,
     /* lmask */ CD_MASK_MLOOP,
 };
 const CustomData_MeshMasks CD_MASK_BAREMESH_ORIGINDEX = {
-    /* vmask */ CD_MASK_MVERT | CD_MASK_BWEIGHT | CD_MASK_ORIGINDEX,
-    /* emask */ CD_MASK_MEDGE | CD_MASK_BWEIGHT | CD_MASK_ORIGINDEX,
+    /* vmask */ CD_MASK_MVERT | CD_MASK_ORIGINDEX,
+    /* emask */ CD_MASK_MEDGE | CD_MASK_ORIGINDEX,
     /* fmask */ 0,
     /* pmask */ CD_MASK_MPOLY | CD_MASK_FACEMAP | CD_MASK_ORIGINDEX,
     /* lmask */ CD_MASK_MLOOP,
 };
 const CustomData_MeshMasks CD_MASK_MESH = {
     /* vmask */ (CD_MASK_MVERT | CD_MASK_MDEFORMVERT | CD_MASK_MVERT_SKIN | CD_MASK_PAINT_MASK |
-                 CD_MASK_PROP_ALL | CD_MASK_CREASE),
-    /* emask */ (CD_MASK_MEDGE | CD_MASK_FREESTYLE_EDGE | CD_MASK_PROP_ALL),
+                 CD_MASK_PROP_ALL | CD_MASK_CREASE | CD_MASK_BWEIGHT),
+    /* emask */ (CD_MASK_MEDGE | CD_MASK_FREESTYLE_EDGE | CD_MASK_PROP_ALL | CD_MASK_BWEIGHT),
     /* fmask */ 0,
     /* pmask */
     (CD_MASK_MPOLY | CD_MASK_FACEMAP | CD_MASK_FREESTYLE_FACE | CD_MASK_PROP_ALL |
@@ -2100,8 +2136,8 @@ const CustomData_MeshMasks CD_MASK_MESH = {
 const CustomData_MeshMasks CD_MASK_DERIVEDMESH = {
     /* vmask */ (CD_MASK_ORIGINDEX | CD_MASK_MDEFORMVERT | CD_MASK_SHAPEKEY | CD_MASK_MVERT_SKIN |
                  CD_MASK_PAINT_MASK | CD_MASK_ORCO | CD_MASK_CLOTH_ORCO | CD_MASK_PROP_ALL |
-                 CD_MASK_CREASE),
-    /* emask */ (CD_MASK_ORIGINDEX | CD_MASK_FREESTYLE_EDGE | CD_MASK_PROP_ALL),
+                 CD_MASK_CREASE | CD_MASK_BWEIGHT),
+    /* emask */ (CD_MASK_ORIGINDEX | CD_MASK_FREESTYLE_EDGE | CD_MASK_BWEIGHT | CD_MASK_PROP_ALL),
     /* fmask */ (CD_MASK_ORIGINDEX | CD_MASK_ORIGSPACE | CD_MASK_PREVIEW_MCOL | CD_MASK_TANGENT),
     /* pmask */
     (CD_MASK_ORIGINDEX | CD_MASK_FREESTYLE_FACE | CD_MASK_FACEMAP | CD_MASK_PROP_ALL |
@@ -2317,8 +2353,16 @@ bool CustomData_merge(const CustomData *source,
       changed = true;
 
       if (layer->anonymous_id != nullptr) {
-        BKE_anonymous_attribute_id_increment_weak(layer->anonymous_id);
         newlayer->anonymous_id = layer->anonymous_id;
+        if (alloctype == CD_ASSIGN) {
+          layer->anonymous_id = nullptr;
+        }
+        else {
+          BKE_anonymous_attribute_id_increment_weak(layer->anonymous_id);
+        }
+      }
+      if (alloctype == CD_ASSIGN) {
+        layer->data = nullptr;
       }
     }
   }
@@ -2327,19 +2371,74 @@ bool CustomData_merge(const CustomData *source,
   return changed;
 }
 
-void CustomData_realloc(CustomData *data, int totelem)
+static bool attribute_stored_in_bmesh_flag(const StringRef name)
+{
+  return ELEM(name, ".hide_vert", ".hide_edge", ".hide_poly", "material_index");
+}
+
+static CustomData shallow_copy_remove_non_bmesh_attributes(const CustomData &src)
 {
-  BLI_assert(totelem >= 0);
+  Vector dst_layers;
+  for (const CustomDataLayer &layer : Span{src.layers, src.totlayer}) {
+    if (!attribute_stored_in_bmesh_flag(layer.name)) {
+      dst_layers.append(layer);
+    }
+  }
+
+  CustomData dst = src;
+  dst.layers = static_cast(
+      MEM_calloc_arrayN(dst_layers.size(), sizeof(CustomDataLayer), __func__));
+  dst.totlayer = dst_layers.size();
+  memcpy(dst.layers, dst_layers.data(), dst_layers.as_span().size_in_bytes());
+
+  CustomData_update_typemap(&dst);
+
+  return dst;
+}
+
+bool CustomData_merge_mesh_to_bmesh(const CustomData *source,
+                                    CustomData *dest,
+                                    const eCustomDataMask mask,
+                                    const eCDAllocType alloctype,
+                                    const int totelem)
+{
+  CustomData source_copy = shallow_copy_remove_non_bmesh_attributes(*source);
+  const bool result = CustomData_merge(&source_copy, dest, mask, alloctype, totelem);
+  MEM_SAFE_FREE(source_copy.layers);
+  return result;
+}
+
+void CustomData_realloc(CustomData *data, const int old_size, const int new_size)
+{
+  BLI_assert(new_size >= 0);
   for (int i = 0; i < data->totlayer; i++) {
     CustomDataLayer *layer = &data->layers[i];
-    const LayerTypeInfo *typeInfo;
+    const LayerTypeInfo *typeInfo = layerType_getInfo(layer->type);
+
+    const int64_t old_size_in_bytes = int64_t(old_size) * typeInfo->size;
+    const int64_t new_size_in_bytes = int64_t(new_size) * typeInfo->size;
     if (layer->flag & CD_FLAG_NOFREE) {
-      continue;
+      const void *old_data = layer->data;
+      layer->data = MEM_malloc_arrayN(new_size, typeInfo->size, __func__);
+      if (typeInfo->copy) {
+        typeInfo->copy(old_data, layer->data, std::min(old_size, new_size));
+      }
+      else {
+        std::memcpy(layer->data, old_data, std::min(old_size_in_bytes, new_size_in_bytes));
+      }
+      layer->flag &= ~CD_FLAG_NOFREE;
+    }
+    else {
+      layer->data = MEM_reallocN(layer->data, new_size_in_bytes);
+    }
+
+    if (new_size > old_size) {
+      /* Initialize new values for non-trivial types. */
+      if (typeInfo->construct) {
+        const int new_elements_num = new_size - old_size;
+        typeInfo->construct(POINTER_OFFSET(layer->data, old_size_in_bytes), new_elements_num);
+      }
     }
-    typeInfo = layerType_getInfo(layer->type);
-    /* Use calloc to avoid the need to manually initialize new data in layers.
-     * Useful for types like #MDeformVert which contain a pointer. */
-    layer->data = MEM_recallocN(layer->data, (size_t)totelem * typeInfo->size);
   }
 }
 
@@ -2358,7 +2457,18 @@ void CustomData_copy(const CustomData *source,
   CustomData_merge(source, dest, mask, alloctype, totelem);
 }
 
-static void customData_free_layer__internal(CustomDataLayer *layer, int totelem)
+void CustomData_copy_mesh_to_bmesh(const CustomData *source,
+                                   CustomData *dest,
+                                   const eCustomDataMask mask,
+                                   const eCDAllocType alloctype,
+                                   const int totelem)
+{
+  CustomData source_copy = shallow_copy_remove_non_bmesh_attributes(*source);
+  CustomData_copy(&source_copy, dest, mask, alloctype, totelem);
+  MEM_SAFE_FREE(source_copy.layers);
+}
+
+static void customData_free_layer__internal(CustomDataLayer *layer, const int totelem)
 {
   const LayerTypeInfo *typeInfo;
 
@@ -2393,7 +2503,7 @@ void CustomData_reset(CustomData *data)
   copy_vn_i(data->typemap, CD_NUMTYPES, -1);
 }
 
-void CustomData_free(CustomData *data, int totelem)
+void CustomData_free(CustomData *data, const int totelem)
 {
   for (int i = 0; i < data->totlayer; i++) {
     customData_free_layer__internal(&data->layers[i], totelem);
@@ -2407,7 +2517,7 @@ void CustomData_free(CustomData *data, int totelem)
   CustomData_reset(data);
 }
 
-void CustomData_free_typemask(CustomData *data, int totelem, eCustomDataMask mask)
+void CustomData_free_typemask(CustomData *data, const int totelem, eCustomDataMask mask)
 {
   for (int i = 0; i < data->totlayer; i++) {
     CustomDataLayer *layer = &data->layers[i];
@@ -2442,7 +2552,7 @@ static void customData_update_offsets(CustomData *data)
 }
 
 /* to use when we're in the middle of modifying layers */
-static int CustomData_get_layer_index__notypemap(const CustomData *data, int type)
+static int CustomData_get_layer_index__notypemap(const CustomData *data, const int type)
 {
   for (int i = 0; i < data->totlayer; i++) {
     if (data->layers[i].type == type) {
@@ -2456,13 +2566,13 @@ static int CustomData_get_layer_index__notypemap(const CustomData *data, int typ
 /* -------------------------------------------------------------------- */
 /* index values to access the layers (offset from the layer start) */
 
-int CustomData_get_layer_index(const CustomData *data, int type)
+int CustomData_get_layer_index(const CustomData *data, const int type)
 {
   BLI_assert(customdata_typemap_is_valid(data));
   return data->typemap[type];
 }
 
-int CustomData_get_layer_index_n(const CustomData *data, int type, int n)
+int CustomData_get_layer_index_n(const CustomData *data, const int type, const int n)
 {
   BLI_assert(n >= 0);
   int i = CustomData_get_layer_index(data, type);
@@ -2475,7 +2585,7 @@ int CustomData_get_layer_index_n(const CustomData *data, int type, int n)
   return i;
 }
 
-int CustomData_get_named_layer_index(const CustomData *data, int type, const char *name)
+int CustomData_get_named_layer_index(const CustomData *data, const int type, const char *name)
 {
   for (int i = 0; i < data->totlayer; i++) {
     if (data->layers[i].type == type) {
@@ -2488,28 +2598,28 @@ int CustomData_get_named_layer_index(const CustomData *data, int type, const cha
   return -1;
 }
 
-int CustomData_get_active_layer_index(const CustomData *data, int type)
+int CustomData_get_active_layer_index(const CustomData *data, const int type)
 {
   const int layer_index = data->typemap[type];
   BLI_assert(customdata_typemap_is_valid(data));
   return (layer_index != -1) ? layer_index + data->layers[layer_index].active : -1;
 }
 
-int CustomData_get_render_layer_index(const CustomData *data, int type)
+int CustomData_get_render_layer_index(const CustomData *data, const int type)
 {
   const int layer_index = data->typemap[type];
   BLI_assert(customdata_typemap_is_valid(data));
   return (layer_index != -1) ? layer_index + data->layers[layer_index].active_rnd : -1;
 }
 
-int CustomData_get_clone_layer_index(const CustomData *data, int type)
+int CustomData_get_clone_layer_index(const CustomData *data, const int type)
 {
   const int layer_index = data->typemap[type];
   BLI_assert(customdata_typemap_is_valid(data));
   return (layer_index != -1) ? layer_index + data->layers[layer_index].active_clone : -1;
 }
 
-int CustomData_get_stencil_layer_index(const CustomData *data, int type)
+int CustomData_get_stencil_layer_index(const CustomData *data, const int type)
 {
   const int layer_index = data->typemap[type];
   BLI_assert(customdata_typemap_is_valid(data));
@@ -2519,7 +2629,7 @@ int CustomData_get_stencil_layer_index(const CustomData *data, int type)
 /* -------------------------------------------------------------------- */
 /* index values per layer type */
 
-int CustomData_get_named_layer(const CustomData *data, int type, const char *name)
+int CustomData_get_named_layer(const CustomData *data, const int type, const char *name)
 {
   const int named_index = CustomData_get_named_layer_index(data, type, name);
   const int layer_index = data->typemap[type];
@@ -2527,28 +2637,28 @@ int CustomData_get_named_layer(const CustomData *data, int type, const char *nam
   return (named_index != -1) ? named_index - layer_index : -1;
 }
 
-int CustomData_get_active_layer(const CustomData *data, int type)
+int CustomData_get_active_layer(const CustomData *data, const int type)
 {
   const int layer_index = data->typemap[type];
   BLI_assert(customdata_typemap_is_valid(data));
   return (layer_index != -1) ? data->layers[layer_index].active : -1;
 }
 
-int CustomData_get_render_layer(const CustomData *data, int type)
+int CustomData_get_render_layer(const CustomData *data, const int type)
 {
   const int layer_index = data->typemap[type];
   BLI_assert(customdata_typemap_is_valid(data));
   return (layer_index != -1) ? data->layers[layer_index].active_rnd : -1;
 }
 
-int CustomData_get_clone_layer(const CustomData *data, int type)
+int CustomData_get_clone_layer(const CustomData *data, const int type)
 {
   const int layer_index = data->typemap[type];
   BLI_assert(customdata_typemap_is_valid(data));
   return (layer_index != -1) ? data->layers[layer_index].active_clone : -1;
 }
 
-int CustomData_get_stencil_layer(const CustomData *data, int type)
+int CustomData_get_stencil_layer(const CustomData *data, const int type)
 {
   const int layer_index = data->typemap[type];
   BLI_assert(customdata_typemap_is_valid(data));
@@ -2562,7 +2672,13 @@ const char *CustomData_get_active_layer_name(const CustomData *data, const int t
   return layer_index < 0 ? nullptr : data->layers[layer_index].name;
 }
 
-void CustomData_set_layer_active(CustomData *data, int type, int n)
+const char *CustomData_get_render_layer_name(const CustomData *data, const int type)
+{
+  const int layer_index = CustomData_get_render_layer_index(data, type);
+  return layer_index < 0 ? nullptr : data->layers[layer_index].name;
+}
+
+void CustomData_set_layer_active(CustomData *data, const int type, const int n)
 {
   for (int i = 0; i < data->totlayer; i++) {
     if (data->layers[i].type == type) {
@@ -2571,7 +2687,7 @@ void CustomData_set_layer_active(CustomData *data, int type, int n)
   }
 }
 
-void CustomData_set_layer_render(CustomData *data, int type, int n)
+void CustomData_set_layer_render(CustomData *data, const int type, const int n)
 {
   for (int i = 0; i < data->totlayer; i++) {
     if (data->layers[i].type == type) {
@@ -2580,7 +2696,7 @@ void CustomData_set_layer_render(CustomData *data, int type, int n)
   }
 }
 
-void CustomData_set_layer_clone(CustomData *data, int type, int n)
+void CustomData_set_layer_clone(CustomData *data, const int type, const int n)
 {
   for (int i = 0; i < data->totlayer; i++) {
     if (data->layers[i].type == type) {
@@ -2589,7 +2705,7 @@ void CustomData_set_layer_clone(CustomData *data, int type, int n)
   }
 }
 
-void CustomData_set_layer_stencil(CustomData *data, int type, int n)
+void CustomData_set_layer_stencil(CustomData *data, const int type, const int n)
 {
   for (int i = 0; i < data->totlayer; i++) {
     if (data->layers[i].type == type) {
@@ -2598,7 +2714,7 @@ void CustomData_set_layer_stencil(CustomData *data, int type, int n)
   }
 }
 
-void CustomData_set_layer_active_index(CustomData *data, int type, int n)
+void CustomData_set_layer_active_index(CustomData *data, const int type, const int n)
 {
   const int layer_index = data->typemap[type];
   BLI_assert(customdata_typemap_is_valid(data));
@@ -2610,7 +2726,7 @@ void CustomData_set_layer_active_index(CustomData *data, int type, int n)
   }
 }
 
-void CustomData_set_layer_render_index(CustomData *data, int type, int n)
+void CustomData_set_layer_render_index(CustomData *data, const int type, const int n)
 {
   const int layer_index = data->typemap[type];
   BLI_assert(customdata_typemap_is_valid(data));
@@ -2622,7 +2738,7 @@ void CustomData_set_layer_render_index(CustomData *data, int type, int n)
   }
 }
 
-void CustomData_set_layer_clone_index(CustomData *data, int type, int n)
+void CustomData_set_layer_clone_index(CustomData *data, const int type, const int n)
 {
   const int layer_index = data->typemap[type];
   BLI_assert(customdata_typemap_is_valid(data));
@@ -2634,7 +2750,7 @@ void CustomData_set_layer_clone_index(CustomData *data, int type, int n)
   }
 }
 
-void CustomData_set_layer_stencil_index(CustomData *data, int type, int n)
+void CustomData_set_layer_stencil_index(CustomData *data, const int type, const int n)
 {
   const int layer_index = data->typemap[type];
   BLI_assert(customdata_typemap_is_valid(data));
@@ -2646,7 +2762,7 @@ void CustomData_set_layer_stencil_index(CustomData *data, int type, int n)
   }
 }
 
-void CustomData_set_layer_flag(CustomData *data, int type, int flag)
+void CustomData_set_layer_flag(CustomData *data, const int type, const int flag)
 {
   for (int i = 0; i < data->totlayer; i++) {
     if (data->layers[i].type == type) {
@@ -2655,7 +2771,7 @@ void CustomData_set_layer_flag(CustomData *data, int type, int flag)
   }
 }
 
-void CustomData_clear_layer_flag(CustomData *data, int type, int flag)
+void CustomData_clear_layer_flag(CustomData *data, const int type, const int flag)
 {
   const int nflag = ~flag;
 
@@ -2666,7 +2782,7 @@ void CustomData_clear_layer_flag(CustomData *data, int type, int flag)
   }
 }
 
-static bool customData_resize(CustomData *data, int amount)
+static bool customData_resize(CustomData *data, const int amount)
 {
   CustomDataLayer *tmp = static_cast(
       MEM_calloc_arrayN((data->maxlayer + amount), sizeof(*tmp), __func__));
@@ -2685,59 +2801,72 @@ static bool customData_resize(CustomData *data, int amount)
 }
 
 static CustomDataLayer *customData_add_layer__internal(CustomData *data,
-                                                       int type,
-                                                       eCDAllocType alloctype,
+                                                       const int type,
+                                                       const eCDAllocType alloctype,
                                                        void *layerdata,
-                                                       int totelem,
+                                                       const int totelem,
                                                        const char *name)
 {
   const LayerTypeInfo *typeInfo = layerType_getInfo(type);
-  int flag = 0, index = data->totlayer;
-  void *newlayerdata = nullptr;
-
-  /* Passing a layer-data to copy from with an alloctype that won't copy is
-   * most likely a bug */
-  BLI_assert(!layerdata || ELEM(alloctype, CD_ASSIGN, CD_DUPLICATE, CD_REFERENCE));
+  int flag = 0;
 
   if (!typeInfo->defaultname && CustomData_has_layer(data, type)) {
     return &data->layers[CustomData_get_layer_index(data, type)];
   }
 
-  if (ELEM(alloctype, CD_ASSIGN, CD_REFERENCE)) {
-    newlayerdata = layerdata;
-  }
-  else if (totelem > 0 && typeInfo->size > 0) {
-    if (alloctype == CD_DUPLICATE && layerdata) {
-      newlayerdata = MEM_malloc_arrayN((size_t)totelem, typeInfo->size, layerType_getName(type));
-    }
-    else {
-      newlayerdata = MEM_calloc_arrayN((size_t)totelem, typeInfo->size, layerType_getName(type));
-    }
-
-    if (!newlayerdata) {
-      return nullptr;
-    }
-  }
-
-  if (alloctype == CD_DUPLICATE && layerdata) {
-    if (totelem > 0) {
-      if (typeInfo->copy) {
-        typeInfo->copy(layerdata, newlayerdata, totelem);
+  void *newlayerdata = nullptr;
+  switch (alloctype) {
+    case CD_SET_DEFAULT:
+      if (totelem > 0) {
+        if (typeInfo->set_default_value) {
+          newlayerdata = MEM_malloc_arrayN(totelem, typeInfo->size, layerType_getName(type));
+          typeInfo->set_default_value(newlayerdata, totelem);
+        }
+        else {
+          newlayerdata = MEM_calloc_arrayN(totelem, typeInfo->size, layerType_getName(type));
+        }
+      }
+      break;
+    case CD_CONSTRUCT:
+      if (totelem > 0) {
+        newlayerdata = MEM_malloc_arrayN(totelem, typeInfo->size, layerType_getName(type));
+        if (typeInfo->construct) {
+          typeInfo->construct(newlayerdata, totelem);
+        }
+      }
+      break;
+    case CD_ASSIGN:
+      if (totelem > 0) {
+        BLI_assert(layerdata != nullptr);
+        newlayerdata = layerdata;
       }
       else {
-        memcpy(newlayerdata, layerdata, (size_t)totelem * typeInfo->size);
+        MEM_SAFE_FREE(layerdata);
       }
-    }
-  }
-  else if (alloctype == CD_DEFAULT) {
-    if (typeInfo->set_default) {
-      typeInfo->set_default(newlayerdata, totelem);
-    }
-  }
-  else if (alloctype == CD_REFERENCE) {
-    flag |= CD_FLAG_NOFREE;
+      break;
+    case CD_REFERENCE:
+      if (totelem > 0) {
+        BLI_assert(layerdata != nullptr);
+        newlayerdata = layerdata;
+        flag |= CD_FLAG_NOFREE;
+      }
+      break;
+    case CD_DUPLICATE:
+      if (totelem > 0) {
+        newlayerdata = MEM_malloc_arrayN(totelem, typeInfo->size, layerType_getName(type));
+        if (typeInfo->copy) {
+          typeInfo->copy(layerdata, newlayerdata, totelem);
+        }
+        else {
+          BLI_assert(layerdata != nullptr);
+          BLI_assert(newlayerdata != nullptr);
+          memcpy(newlayerdata, layerdata, totelem * typeInfo->size);
+        }
+      }
+      break;
   }
 
+  int index = data->totlayer;
   if (index >= data->maxlayer) {
     if (!customData_resize(data, CUSTOMDATA_GROW)) {
       if (newlayerdata != layerdata) {
@@ -2754,14 +2883,16 @@ static CustomDataLayer *customData_add_layer__internal(CustomData *data,
     data->layers[index] = data->layers[index - 1];
   }
 
+  CustomDataLayer &new_layer = data->layers[index];
+
   /* Clear remaining data on the layer. The original data on the layer has been moved to another
    * index. Without this, it can happen that information from the previous layer at that index
    * leaks into the new layer. */
-  memset(data->layers + index, 0, sizeof(CustomDataLayer));
+  memset(&new_layer, 0, sizeof(CustomDataLayer));
 
-  data->layers[index].type = type;
-  data->layers[index].flag = flag;
-  data->layers[index].data = newlayerdata;
+  new_layer.type = type;
+  new_layer.flag = flag;
+  new_layer.data = newlayerdata;
 
   /* Set default name if none exists. Note we only call DATA_()  once
    * we know there is a default name, to avoid overhead of locale lookups
@@ -2771,24 +2902,24 @@ static CustomDataLayer *customData_add_layer__internal(CustomData *data,
   }
 
   if (name) {
-    BLI_strncpy(data->layers[index].name, name, sizeof(data->layers[index].name));
+    BLI_strncpy(new_layer.name, name, sizeof(new_layer.name));
     CustomData_set_layer_unique_name(data, index);
   }
   else {
-    data->layers[index].name[0] = '\0';
+    new_layer.name[0] = '\0';
   }
 
   if (index > 0 && data->layers[index - 1].type == type) {
-    data->layers[index].active = data->layers[index - 1].active;
-    data->layers[index].active_rnd = data->layers[index - 1].active_rnd;
-    data->layers[index].active_clone = data->layers[index - 1].active_clone;
-    data->layers[index].active_mask = data->layers[index - 1].active_mask;
+    new_layer.active = data->layers[index - 1].active;
+    new_layer.active_rnd = data->layers[index - 1].active_rnd;
+    new_layer.active_clone = data->layers[index - 1].active_clone;
+    new_layer.active_mask = data->layers[index - 1].active_mask;
   }
   else {
-    data->layers[index].active = 0;
-    data->layers[index].active_rnd = 0;
-    data->layers[index].active_clone = 0;
-    data->layers[index].active_mask = 0;
+    new_layer.active = 0;
+    new_layer.active_rnd = 0;
+    new_layer.active_clone = 0;
+    new_layer.active_mask = 0;
   }
 
   customData_update_offsets(data);
@@ -2797,7 +2928,7 @@ static CustomDataLayer *customData_add_layer__internal(CustomData *data,
 }
 
 void *CustomData_add_layer(
-    CustomData *data, int type, eCDAllocType alloctype, void *layerdata, int totelem)
+    CustomData *data, const int type, eCDAllocType alloctype, void *layerdata, const int totelem)
 {
   const LayerTypeInfo *typeInfo = layerType_getInfo(type);
 
@@ -2813,10 +2944,10 @@ void *CustomData_add_layer(
 }
 
 void *CustomData_add_layer_named(CustomData *data,
-                                 int type,
-                                 eCDAllocType alloctype,
+                                 const int type,
+                                 const eCDAllocType alloctype,
                                  void *layerdata,
-                                 int totelem,
+                                 const int totelem,
                                  const char *name)
 {
   CustomDataLayer *layer = customData_add_layer__internal(
@@ -2831,10 +2962,10 @@ void *CustomData_add_layer_named(CustomData *data,
 }
 
 void *CustomData_add_layer_anonymous(CustomData *data,
-                                     int type,
-                                     eCDAllocType alloctype,
+                                     const int type,
+                                     const eCDAllocType alloctype,
                                      void *layerdata,
-                                     int totelem,
+                                     const int totelem,
                                      const AnonymousAttributeID *anonymous_id)
 {
   const char *name = BKE_anonymous_attribute_id_internal_name(anonymous_id);
@@ -2851,7 +2982,7 @@ void *CustomData_add_layer_anonymous(CustomData *data,
   return layer->data;
 }
 
-bool CustomData_free_layer(CustomData *data, int type, int totelem, int index)
+bool CustomData_free_layer(CustomData *data, const int type, const int totelem, const int index)
 {
   const int index_first = CustomData_get_layer_index(data, type);
   const int n = index - index_first;
@@ -2915,7 +3046,7 @@ bool CustomData_free_layer_named(CustomData *data, const char *name, const int t
   return false;
 }
 
-bool CustomData_free_layer_active(CustomData *data, int type, int totelem)
+bool CustomData_free_layer_active(CustomData *data, const int type, const int totelem)
 {
   const int index = CustomData_get_active_layer_index(data, type);
   if (index == -1) {
@@ -2924,7 +3055,7 @@ bool CustomData_free_layer_active(CustomData *data, int type, int totelem)
   return CustomData_free_layer(data, type, totelem, index);
 }
 
-void CustomData_free_layers(CustomData *data, int type, int totelem)
+void CustomData_free_layers(CustomData *data, const int type, const int totelem)
 {
   const int index = CustomData_get_layer_index(data, type);
   while (CustomData_free_layer(data, type, totelem, index)) {
@@ -2932,12 +3063,12 @@ void CustomData_free_layers(CustomData *data, int type, int totelem)
   }
 }
 
-bool CustomData_has_layer(const CustomData *data, int type)
+bool CustomData_has_layer(const CustomData *data, const int type)
 {
   return (CustomData_get_layer_index(data, type) != -1);
 }
 
-int CustomData_number_of_layers(const CustomData *data, int type)
+int CustomData_number_of_layers(const CustomData *data, const int type)
 {
   int number = 0;
 
@@ -2950,7 +3081,7 @@ int CustomData_number_of_layers(const CustomData *data, int type)
   return number;
 }
 
-int CustomData_number_of_layers_typemask(const CustomData *data, eCustomDataMask mask)
+int CustomData_number_of_layers_typemask(const CustomData *data, const eCustomDataMask mask)
 {
   int number = 0;
 
@@ -3040,7 +3171,7 @@ void *CustomData_duplicate_referenced_layer_anonymous(CustomData *data,
   return nullptr;
 }
 
-void CustomData_duplicate_referenced_layers(CustomData *data, int totelem)
+void CustomData_duplicate_referenced_layers(CustomData *data, const int totelem)
 {
   for (int i = 0; i < data->totlayer; i++) {
     CustomDataLayer *layer = &data->layers[i];
@@ -3048,7 +3179,7 @@ void CustomData_duplicate_referenced_layers(CustomData *data, int totelem)
   }
 }
 
-bool CustomData_is_referenced_layer(CustomData *data, int type)
+bool CustomData_is_referenced_layer(CustomData *data, const int type)
 {
   /* get the layer index of the first layer of type */
   int layer_index = CustomData_get_active_layer_index(data, type);
@@ -3061,7 +3192,7 @@ bool CustomData_is_referenced_layer(CustomData *data, int type)
   return (layer->flag & CD_FLAG_NOFREE) != 0;
 }
 
-void CustomData_free_temporary(CustomData *data, int totelem)
+void CustomData_free_temporary(CustomData *data, const int totelem)
 {
   int i, j;
   bool changed = false;
@@ -3093,7 +3224,7 @@ void CustomData_free_temporary(CustomData *data, int totelem)
   }
 }
 
-void CustomData_set_only_copy(const CustomData *data, eCustomDataMask mask)
+void CustomData_set_only_copy(const CustomData *data, const eCustomDataMask mask)
 {
   for (int i = 0; i < data->totlayer; i++) {
     if (!(mask & CD_TYPE_AS_MASK(data->layers[i].type))) {
@@ -3102,7 +3233,10 @@ void CustomData_set_only_copy(const CustomData *data, eCustomDataMask mask)
   }
 }
 
-void CustomData_copy_elements(int type, void *src_data_ofs, void *dst_data_ofs, int count)
+void CustomData_copy_elements(const int type,
+                              void *src_data_ofs,
+                              void *dst_data_ofs,
+                              const int count)
 {
   const LayerTypeInfo *typeInfo = layerType_getInfo(type);
 
@@ -3116,11 +3250,11 @@ void CustomData_copy_elements(int type, void *src_data_ofs, void *dst_data_ofs,
 
 void CustomData_copy_data_layer(const CustomData *source,
                                 CustomData *dest,
-                                int src_layer_index,
-                                int dst_layer_index,
-                                int src_index,
-                                int dst_index,
-                                int count)
+                                const int src_layer_index,
+                                const int dst_layer_index,
+                                const int src_index,
+                                const int dst_index,
+                                const int count)
 {
   const LayerTypeInfo *typeInfo;
 
@@ -3154,8 +3288,11 @@ void CustomData_copy_data_layer(const CustomData *source,
   }
 }
 
-void CustomData_copy_data_named(
-    const CustomData *source, CustomData *dest, int source_index, int dest_index, int count)
+void CustomData_copy_data_named(const CustomData *source,
+                                CustomData *dest,
+                                const int source_index,
+                                const int dest_index,
+                                const int count)
 {
   /* copies a layer at a time */
   for (int src_i = 0; src_i < source->totlayer; src_i++) {
@@ -3170,8 +3307,11 @@ void CustomData_copy_data_named(
   }
 }
 
-void CustomData_copy_data(
-    const CustomData *source, CustomData *dest, int source_index, int dest_index, int count)
+void CustomData_copy_data(const CustomData *source,
+                          CustomData *dest,
+                          const int source_index,
+                          const int dest_index,
+                          const int count)
 {
   /* copies a layer at a time */
   int dest_i = 0;
@@ -3226,7 +3366,7 @@ void CustomData_copy_layer_type_data(const CustomData *source,
                              count);
 }
 
-void CustomData_free_elem(CustomData *data, int index, int count)
+void CustomData_free_elem(CustomData *data, const int index, const int count)
 {
   for (int i = 0; i < data->totlayer; i++) {
     if (!(data->layers[i].flag & CD_FLAG_NOFREE)) {
@@ -3326,7 +3466,7 @@ void CustomData_interp(const CustomData *source,
   }
 }
 
-void CustomData_swap_corners(CustomData *data, int index, const int *corner_indices)
+void CustomData_swap_corners(CustomData *data, const int index, const int *corner_indices)
 {
   for (int i = 0; i < data->totlayer; i++) {
     const LayerTypeInfo *typeInfo = layerType_getInfo(data->layers[i].type);
@@ -3366,7 +3506,7 @@ void CustomData_swap(CustomData *data, const int index_a, const int index_b)
   }
 }
 
-void *CustomData_get(const CustomData *data, int index, int type)
+void *CustomData_get(const CustomData *data, const int index, const int type)
 {
   BLI_assert(index >= 0);
 
@@ -3382,7 +3522,7 @@ void *CustomData_get(const CustomData *data, int index, int type)
   return POINTER_OFFSET(data->layers[layer_index].data, offset);
 }
 
-void *CustomData_get_n(const CustomData *data, int type, int index, int n)
+void *CustomData_get_n(const CustomData *data, const int type, const int index, const int n)
 {
   BLI_assert(index >= 0 && n >= 0);
 
@@ -3396,7 +3536,7 @@ void *CustomData_get_n(const CustomData *data, int type, int index, int n)
   return POINTER_OFFSET(data->layers[layer_index + n].data, offset);
 }
 
-void *CustomData_get_layer(const CustomData *data, int type)
+void *CustomData_get_layer(const CustomData *data, const int type)
 {
   /* get the layer index of the active layer of type */
   int layer_index = CustomData_get_active_layer_index(data, type);
@@ -3407,7 +3547,7 @@ void *CustomData_get_layer(const CustomData *data, int type)
   return data->layers[layer_index].data;
 }
 
-void *CustomData_get_layer_n(const CustomData *data, int type, int n)
+void *CustomData_get_layer_n(const CustomData *data, const int type, const int n)
 {
   /* get the layer index of the active layer of type */
   int layer_index = CustomData_get_layer_index_n(data, type, n);
@@ -3418,7 +3558,7 @@ void *CustomData_get_layer_n(const CustomData *data, int type, int n)
   return data->layers[layer_index].data;
 }
 
-void *CustomData_get_layer_named(const CustomData *data, int type, const char *name)
+void *CustomData_get_layer_named(const CustomData *data, const int type, const char *name)
 {
   int layer_index = CustomData_get_named_layer_index(data, type, name);
   if (layer_index == -1) {
@@ -3428,7 +3568,7 @@ void *CustomData_get_layer_named(const CustomData *data, int type, const char *n
   return data->layers[layer_index].data;
 }
 
-int CustomData_get_offset(const CustomData *data, int type)
+int CustomData_get_offset(const CustomData *data, const int type)
 {
   /* get the layer index of the active layer of type */
   int layer_index = CustomData_get_active_layer_index(data, type);
@@ -3439,7 +3579,7 @@ int CustomData_get_offset(const CustomData *data, int type)
   return data->layers[layer_index].offset;
 }
 
-int CustomData_get_n_offset(const CustomData *data, int type, int n)
+int CustomData_get_n_offset(const CustomData *data, const int type, const int n)
 {
   /* get the layer index of the active layer of type */
   int layer_index = CustomData_get_layer_index_n(data, type, n);
@@ -3450,7 +3590,17 @@ int CustomData_get_n_offset(const CustomData *data, int type, int n)
   return data->layers[layer_index].offset;
 }
 
-bool CustomData_set_layer_name(const CustomData *data, int type, int n, const char *name)
+int CustomData_get_offset_named(const CustomData *data, int type, const char *name)
+{
+  int layer_index = CustomData_get_named_layer_index(data, type, name);
+  if (layer_index == -1) {
+    return -1;
+  }
+
+  return data->layers[layer_index].offset;
+}
+
+bool CustomData_set_layer_name(CustomData *data, const int type, const int n, const char *name)
 {
   /* get the layer index of the first layer of type */
   const int layer_index = CustomData_get_layer_index_n(data, type, n);
@@ -3464,14 +3614,14 @@ bool CustomData_set_layer_name(const CustomData *data, int type, int n, const ch
   return true;
 }
 
-const char *CustomData_get_layer_name(const CustomData *data, int type, int n)
+const char *CustomData_get_layer_name(const CustomData *data, const int type, const int n)
 {
   const int layer_index = CustomData_get_layer_index_n(data, type, n);
 
   return (layer_index == -1) ? nullptr : data->layers[layer_index].name;
 }
 
-void *CustomData_set_layer(const CustomData *data, int type, void *ptr)
+void *CustomData_set_layer(const CustomData *data, const int type, void *ptr)
 {
   /* get the layer index of the first layer of type */
   int layer_index = CustomData_get_active_layer_index(data, type);
@@ -3485,7 +3635,7 @@ void *CustomData_set_layer(const CustomData *data, int type, void *ptr)
   return ptr;
 }
 
-void *CustomData_set_layer_n(const CustomData *data, int type, int n, void *ptr)
+void *CustomData_set_layer_n(const CustomData *data, const int type, const int n, void *ptr)
 {
   /* get the layer index of the first layer of type */
   int layer_index = CustomData_get_layer_index_n(data, type, n);
@@ -3498,7 +3648,7 @@ void *CustomData_set_layer_n(const CustomData *data, int type, int n, void *ptr)
   return ptr;
 }
 
-void CustomData_set(const CustomData *data, int index, int type, const void *source)
+void CustomData_set(const CustomData *data, const int index, const int type, const void *source)
 {
   void *dest = CustomData_get(data, index, type);
   const LayerTypeInfo *typeInfo = layerType_getInfo(type);
@@ -3550,7 +3700,7 @@ void CustomData_bmesh_update_active_layers(CustomData *fdata, CustomData *ldata)
   }
 }
 
-void CustomData_bmesh_init_pool(CustomData *data, int totelem, const char htype)
+void CustomData_bmesh_init_pool(CustomData *data, const int totelem, const char htype)
 {
   int chunksize;
 
@@ -3601,7 +3751,7 @@ bool CustomData_bmesh_merge(const CustomData *source,
     destold.layers = static_cast(MEM_dupallocN(destold.layers));
   }
 
-  if (CustomData_merge(source, dest, mask, alloctype, 0) == false) {
+  if (CustomData_merge_mesh_to_bmesh(source, dest, mask, alloctype, 0) == false) {
     if (destold.layers) {
       MEM_freeN(destold.layers);
     }
@@ -3752,13 +3902,13 @@ void CustomData_bmesh_free_block_data_exclude_by_type(CustomData *data,
   }
 }
 
-static void CustomData_bmesh_set_default_n(CustomData *data, void **block, int n)
+static void CustomData_bmesh_set_default_n(CustomData *data, void **block, const int n)
 {
   int offset = data->layers[n].offset;
   const LayerTypeInfo *typeInfo = layerType_getInfo(data->layers[n].type);
 
-  if (typeInfo->set_default) {
-    typeInfo->set_default(POINTER_OFFSET(*block, offset), 1);
+  if (typeInfo->set_default_value) {
+    typeInfo->set_default_value(POINTER_OFFSET(*block, offset), 1);
   }
   else {
     memset(POINTER_OFFSET(*block, offset), 0, typeInfo->size);
@@ -3847,7 +3997,7 @@ void CustomData_bmesh_copy_data(const CustomData *source,
   CustomData_bmesh_copy_data_exclude_by_type(source, dest, src_block, dest_block, 0);
 }
 
-void *CustomData_bmesh_get(const CustomData *data, void *block, int type)
+void *CustomData_bmesh_get(const CustomData *data, void *block, const int type)
 {
   /* get the layer index of the first layer of type */
   int layer_index = CustomData_get_active_layer_index(data, type);
@@ -3858,7 +4008,7 @@ void *CustomData_bmesh_get(const CustomData *data, void *block, int type)
   return POINTER_OFFSET(block, data->layers[layer_index].offset);
 }
 
-void *CustomData_bmesh_get_n(const CustomData *data, void *block, int type, int n)
+void *CustomData_bmesh_get_n(const CustomData *data, void *block, const int type, const int n)
 {
   /* get the layer index of the first layer of type */
   int layer_index = CustomData_get_layer_index(data, type);
@@ -3869,7 +4019,7 @@ void *CustomData_bmesh_get_n(const CustomData *data, void *block, int type, int
   return POINTER_OFFSET(block, data->layers[layer_index + n].offset);
 }
 
-void *CustomData_bmesh_get_layer_n(const CustomData *data, void *block, int n)
+void *CustomData_bmesh_get_layer_n(const CustomData *data, void *block, const int n)
 {
   if (n < 0 || n >= data->totlayer) {
     return nullptr;
@@ -3878,7 +4028,7 @@ void *CustomData_bmesh_get_layer_n(const CustomData *data, void *block, int n)
   return POINTER_OFFSET(block, data->layers[n].offset);
 }
 
-bool CustomData_layer_has_math(const CustomData *data, int layer_n)
+bool CustomData_layer_has_math(const CustomData *data, const int layer_n)
 {
   const LayerTypeInfo *typeInfo = layerType_getInfo(data->layers[layer_n].type);
 
@@ -3890,7 +4040,7 @@ bool CustomData_layer_has_math(const CustomData *data, int layer_n)
   return false;
 }
 
-bool CustomData_layer_has_interp(const CustomData *data, int layer_n)
+bool CustomData_layer_has_interp(const CustomData *data, const int layer_n)
 {
   const LayerTypeInfo *typeInfo = layerType_getInfo(data->layers[layer_n].type);
 
@@ -4011,7 +4161,7 @@ void CustomData_data_dominmax(int type, const void *data, void *min, void *max)
   }
 }
 
-void CustomData_data_multiply(int type, void *data, float fac)
+void CustomData_data_multiply(int type, void *data, const float fac)
 {
   const LayerTypeInfo *typeInfo = layerType_getInfo(type);
 
@@ -4029,7 +4179,7 @@ void CustomData_data_add(int type, void *data1, const void *data2)
   }
 }
 
-void CustomData_bmesh_set(const CustomData *data, void *block, int type, const void *source)
+void CustomData_bmesh_set(const CustomData *data, void *block, const int type, const void *source)
 {
   void *dest = CustomData_bmesh_get(data, block, type);
   const LayerTypeInfo *typeInfo = layerType_getInfo(type);
@@ -4046,7 +4196,8 @@ void CustomData_bmesh_set(const CustomData *data, void *block, int type, const v
   }
 }
 
-void CustomData_bmesh_set_n(CustomData *data, void *block, int type, int n, const void *source)
+void CustomData_bmesh_set_n(
+    CustomData *data, void *block, const int type, const int n, const void *source)
 {
   void *dest = CustomData_bmesh_get_n(data, block, type, n);
   const LayerTypeInfo *typeInfo = layerType_getInfo(type);
@@ -4063,7 +4214,7 @@ void CustomData_bmesh_set_n(CustomData *data, void *block, int type, int n, cons
   }
 }
 
-void CustomData_bmesh_set_layer_n(CustomData *data, void *block, int n, const void *source)
+void CustomData_bmesh_set_layer_n(CustomData *data, void *block, const int n, const void *source)
 {
   void *dest = CustomData_bmesh_get_layer_n(data, block, n);
   const LayerTypeInfo *typeInfo = layerType_getInfo(data->layers[n].type);
@@ -4262,7 +4413,9 @@ void CustomData_file_write_info(int type, const char **r_struct_name, int *r_str
   *r_struct_num = typeInfo->structnum;
 }
 
-void CustomData_blend_write_prepare(CustomData &data, Vector &layers_to_write)
+void CustomData_blend_write_prepare(CustomData &data,
+                                    Vector &layers_to_write,
+                                    const Set &skip_names)
 {
   for (const CustomDataLayer &layer : Span(data.layers, data.totlayer)) {
     if (layer.flag & CD_FLAG_NOCOPY) {
@@ -4271,6 +4424,9 @@ void CustomData_blend_write_prepare(CustomData &data, Vectorlayers_max();
 }
 
-static bool cd_layer_find_dupe(CustomData *data, const char *name, int type, int index)
+static bool cd_layer_find_dupe(CustomData *data, const char *name, const int type, const int index)
 {
   /* see if there is a duplicate */
   for (int i = 0; i < data->totlayer; i++) {
@@ -4352,7 +4508,7 @@ static bool customdata_unique_check(void *arg, const char *name)
   return cd_layer_find_dupe(data_arg->data, name, data_arg->type, data_arg->index);
 }
 
-void CustomData_set_layer_unique_name(CustomData *data, int index)
+void CustomData_set_layer_unique_name(CustomData *data, const int index)
 {
   CustomDataLayer *nlayer = &data->layers[index];
   const LayerTypeInfo *typeInfo = layerType_getInfo(nlayer->type);
@@ -4397,7 +4553,7 @@ void CustomData_validate_layer_name(const CustomData *data,
   }
 }
 
-bool CustomData_verify_versions(CustomData *data, int index)
+bool CustomData_verify_versions(CustomData *data, const int index)
 {
   const LayerTypeInfo *typeInfo;
   CustomDataLayer *layer = &data->layers[index];
@@ -4443,9 +4599,52 @@ bool CustomData_verify_versions(CustomData *data, int index)
   return keeplayer;
 }
 
+static bool CustomData_layer_ensure_data_exists(CustomDataLayer *layer, size_t count)
+{
+  BLI_assert(layer);
+  const LayerTypeInfo *typeInfo = layerType_getInfo(layer->type);
+  BLI_assert(typeInfo);
+
+  if (layer->data || count == 0) {
+    return false;
+  }
+
+  switch (layer->type) {
+    /* When more instances of corrupt files are found, add them here. */
+    case CD_PROP_BOOL: /* See T84935. */
+    case CD_MLOOPUV:   /* See T90620. */
+      layer->data = MEM_calloc_arrayN(count, typeInfo->size, layerType_getName(layer->type));
+      BLI_assert(layer->data);
+      if (typeInfo->set_default_value) {
+        typeInfo->set_default_value(layer->data, count);
+      }
+      return true;
+      break;
+
+    case CD_MTEXPOLY:
+      /* TODO: Investigate multiple test failures on cycles, e.g. cycles_shadow_catcher_cpu. */
+      break;
+
+    default:
+      /* Log an error so we can collect instances of bad files. */
+      CLOG_WARN(&LOG, "CustomDataLayer->data is NULL for type %d.", layer->type);
+      break;
+  }
+  return false;
+}
+
 bool CustomData_layer_validate(CustomDataLayer *layer, const uint totitems, const bool do_fixes)
 {
+  BLI_assert(layer);
   const LayerTypeInfo *typeInfo = layerType_getInfo(layer->type);
+  BLI_assert(typeInfo);
+
+  if (do_fixes) {
+    CustomData_layer_ensure_data_exists(layer, totitems);
+  }
+
+  BLI_assert((totitems == 0) || layer->data);
+  BLI_assert(MEM_allocN_len(layer->data) >= totitems * typeInfo->size);
 
   if (typeInfo->validate != nullptr) {
     return typeInfo->validate(layer->data, totitems, do_fixes);
@@ -4513,7 +4712,7 @@ void CustomData_external_reload(CustomData *data,
   }
 }
 
-void CustomData_external_read(CustomData *data, ID *id, eCustomDataMask mask, int totelem)
+void CustomData_external_read(CustomData *data, ID *id, eCustomDataMask mask, const int totelem)
 {
   CustomDataExternal *external = data->external;
   CustomDataLayer *layer;
@@ -4587,7 +4786,7 @@ void CustomData_external_read(CustomData *data, ID *id, eCustomDataMask mask, in
 }
 
 void CustomData_external_write(
-    CustomData *data, ID *id, eCustomDataMask mask, int totelem, int free)
+    CustomData *data, ID *id, eCustomDataMask mask, const int totelem, const int free)
 {
   CustomDataExternal *external = data->external;
   int update = 0;
@@ -4689,8 +4888,11 @@ void CustomData_external_write(
   cdf_free(cdf);
 }
 
-void CustomData_external_add(
-    CustomData *data, ID *UNUSED(id), int type, int UNUSED(totelem), const char *filepath)
+void CustomData_external_add(CustomData *data,
+                             ID *UNUSED(id),
+                             const int type,
+                             const int UNUSED(totelem),
+                             const char *filepath)
 {
   CustomDataExternal *external = data->external;
 
@@ -4714,7 +4916,7 @@ void CustomData_external_add(
   layer->flag |= CD_FLAG_EXTERNAL | CD_FLAG_IN_MEMORY;
 }
 
-void CustomData_external_remove(CustomData *data, ID *id, int type, int totelem)
+void CustomData_external_remove(CustomData *data, ID *id, const int type, const int totelem)
 {
   CustomDataExternal *external = data->external;
 
@@ -4738,7 +4940,7 @@ void CustomData_external_remove(CustomData *data, ID *id, int type, int totelem)
   }
 }
 
-bool CustomData_external_test(CustomData *data, int type)
+bool CustomData_external_test(CustomData *data, const int type)
 {
   int layer_index = CustomData_get_active_layer_index(data, type);
   if (layer_index == -1) {
@@ -4991,7 +5193,7 @@ void CustomData_data_transfer(const MeshPairRemap *me_remap,
   else {
     const LayerTypeInfo *type_info = layerType_getInfo(data_type);
 
-    /* NOTE: we can use 'fake' CDLayers, like e.g. for crease, bweight, etc. :/. */
+    /* NOTE: we can use 'fake' CDLayers for crease :/. */
     data_size = (size_t)type_info->size;
     data_step = laymap->elem_size ? laymap->elem_size : data_size;
     data_offset = laymap->data_offset;
@@ -5039,7 +5241,10 @@ void CustomData_data_transfer(const MeshPairRemap *me_remap,
 /** \name Custom Data IO
  * \{ */
 
-static void write_mdisps(BlendWriter *writer, int count, const MDisps *mdlist, int external)
+static void write_mdisps(BlendWriter *writer,
+                         const int count,
+                         const MDisps *mdlist,
+                         const int external)
 {
   if (mdlist) {
     BLO_write_struct_array(writer, MDisps, count, mdlist);
@@ -5139,7 +5344,10 @@ void CustomData_blend_write(BlendWriter *writer,
   }
 }
 
-static void blend_read_mdisps(BlendDataReader *reader, int count, MDisps *mdisps, int external)
+static void blend_read_mdisps(BlendDataReader *reader,
+                              const int count,
+                              MDisps *mdisps,
+                              const int external)
 {
   if (mdisps) {
     for (int i = 0; i < count; i++) {
@@ -5181,7 +5389,7 @@ static void blend_read_paint_mask(BlendDataReader *reader,
   }
 }
 
-void CustomData_blend_read(BlendDataReader *reader, CustomData *data, int count)
+void CustomData_blend_read(BlendDataReader *reader, CustomData *data, const int count)
 {
   BLO_read_data_address(reader, &data->layers);
 
@@ -5206,16 +5414,15 @@ void CustomData_blend_read(BlendDataReader *reader, CustomData *data, int count)
 
     if (CustomData_verify_versions(data, i)) {
       BLO_read_data_address(reader, &layer->data);
-      if (layer->data == nullptr && count > 0 && layer->type == CD_PROP_BOOL) {
-        /* Usually this should never happen, except when a custom data layer has not been written
-         * to a file correctly. */
-        CLOG_WARN(&LOG, "Reallocating custom data layer that was not saved correctly.");
-        const LayerTypeInfo *info = layerType_getInfo(layer->type);
-        layer->data = MEM_calloc_arrayN((size_t)count, info->size, layerType_getName(layer->type));
-        if (info->set_default) {
-          info->set_default(layer->data, count);
-        }
+      if (CustomData_layer_ensure_data_exists(layer, count)) {
+        /* Under normal operations, this shouldn't happen, but...
+         * For a CD_PROP_BOOL example, see T84935.
+         * For a CD_MLOOPUV example, see T90620. */
+        CLOG_WARN(&LOG,
+                  "Allocated custom data layer that was not saved correctly for layer->type = %d.",
+                  layer->type);
       }
+
       if (layer->type == CD_MDISPS) {
         blend_read_mdisps(
             reader, count, static_cast(layer->data), layer->flag & CD_FLAG_EXTERNAL);
@@ -5223,6 +5430,9 @@ void CustomData_blend_read(BlendDataReader *reader, CustomData *data, int count)
       else if (layer->type == CD_GRID_PAINT_MASK) {
         blend_read_paint_mask(reader, count, static_cast(layer->data));
       }
+      else if (layer->type == CD_MDEFORMVERT) {
+        BKE_defvert_blend_read(reader, count, static_cast(layer->data));
+      }
       i++;
     }
   }
@@ -5336,3 +5546,8 @@ eCustomDataType cpp_type_to_custom_data_type(const blender::CPPType &type)
 /** \} */
 
 }  // namespace blender::bke
+
+size_t CustomData_get_elem_size(CustomDataLayer *layer)
+{
+  return LAYERTYPEINFO[layer->type].size;
+}
diff --git a/source/blender/blenkernel/intern/data_transfer.c b/source/blender/blenkernel/intern/data_transfer.c
index 196a6a00ade..6c7715c625e 100644
--- a/source/blender/blenkernel/intern/data_transfer.c
+++ b/source/blender/blenkernel/intern/data_transfer.c
@@ -70,8 +70,6 @@ void BKE_object_data_transfer_dttypes_to_cdmask(const int dtdata_types,
       r_data_masks->lmask |= CD_MASK_MLOOPUV;
     }
     else if (cddata_type == CD_FAKE_LNOR) {
-      r_data_masks->vmask |= CD_MASK_NORMAL;
-      r_data_masks->pmask |= CD_MASK_NORMAL;
       r_data_masks->lmask |= CD_MASK_NORMAL | CD_MASK_CUSTOMLOOPNORMAL;
     }
   }
@@ -194,7 +192,7 @@ int BKE_object_data_transfer_dttype_to_cdtype(const int dtdata_type)
     case DT_TYPE_SKIN:
       return CD_MVERT_SKIN;
     case DT_TYPE_BWEIGHT_VERT:
-      return CD_FAKE_BWEIGHT;
+      return CD_BWEIGHT;
 
     case DT_TYPE_SHARP_EDGE:
       return CD_FAKE_SHARP;
@@ -203,7 +201,7 @@ int BKE_object_data_transfer_dttype_to_cdtype(const int dtdata_type)
     case DT_TYPE_CREASE:
       return CD_FAKE_CREASE;
     case DT_TYPE_BWEIGHT_EDGE:
-      return CD_FAKE_BWEIGHT;
+      return CD_BWEIGHT;
     case DT_TYPE_FREESTYLE_EDGE:
       return CD_FREESTYLE_EDGE;
 
@@ -258,13 +256,14 @@ static void data_transfer_dtdata_type_preprocess(Mesh *me_src,
 {
   if (dtdata_type == DT_TYPE_LNOR) {
     /* Compute custom normals into regular loop normals, which will be used for the transfer. */
-    MVert *verts_dst = me_dst->mvert;
+
+    const MVert *verts_dst = BKE_mesh_verts(me_dst);
     const int num_verts_dst = me_dst->totvert;
-    MEdge *edges_dst = me_dst->medge;
+    const MEdge *edges_dst = BKE_mesh_edges(me_dst);
     const int num_edges_dst = me_dst->totedge;
-    MPoly *polys_dst = me_dst->mpoly;
+    const MPoly *polys_dst = BKE_mesh_polys(me_dst);
     const int num_polys_dst = me_dst->totpoly;
-    MLoop *loops_dst = me_dst->mloop;
+    const MLoop *loops_dst = BKE_mesh_loops(me_dst);
     const int num_loops_dst = me_dst->totloop;
     CustomData *ldata_dst = &me_dst->ldata;
 
@@ -282,7 +281,8 @@ static void data_transfer_dtdata_type_preprocess(Mesh *me_src,
     loop_nors_dst = CustomData_get_layer(ldata_dst, CD_NORMAL);
     const bool do_loop_nors_dst = (loop_nors_dst == NULL);
     if (do_loop_nors_dst) {
-      loop_nors_dst = CustomData_add_layer(ldata_dst, CD_NORMAL, CD_CALLOC, NULL, num_loops_dst);
+      loop_nors_dst = CustomData_add_layer(
+          ldata_dst, CD_NORMAL, CD_SET_DEFAULT, NULL, num_loops_dst);
       CustomData_set_layer_flag(ldata_dst, CD_NORMAL, CD_FLAG_TEMPORARY);
     }
     if (dirty_nors_dst || do_loop_nors_dst) {
@@ -319,13 +319,13 @@ static void data_transfer_dtdata_type_postprocess(Object *UNUSED(ob_src),
     }
 
     /* Bake edited destination loop normals into custom normals again. */
-    MVert *verts_dst = me_dst->mvert;
+    const MVert *verts_dst = BKE_mesh_verts(me_dst);
     const int num_verts_dst = me_dst->totvert;
-    MEdge *edges_dst = me_dst->medge;
+    MEdge *edges_dst = BKE_mesh_edges_for_write(me_dst);
     const int num_edges_dst = me_dst->totedge;
-    MPoly *polys_dst = me_dst->mpoly;
+    MPoly *polys_dst = BKE_mesh_polys_for_write(me_dst);
     const int num_polys_dst = me_dst->totpoly;
-    MLoop *loops_dst = me_dst->mloop;
+    MLoop *loops_dst = BKE_mesh_loops_for_write(me_dst);
     const int num_loops_dst = me_dst->totloop;
     CustomData *ldata_dst = &me_dst->ldata;
 
@@ -335,7 +335,7 @@ static void data_transfer_dtdata_type_postprocess(Object *UNUSED(ob_src),
 
     if (!custom_nors_dst) {
       custom_nors_dst = CustomData_add_layer(
-          ldata_dst, CD_CUSTOMLOOPNORMAL, CD_CALLOC, NULL, num_loops_dst);
+          ldata_dst, CD_CUSTOMLOOPNORMAL, CD_SET_DEFAULT, NULL, num_loops_dst);
     }
 
     /* Note loop_nors_dst contains our custom normals as transferred from source... */
@@ -563,7 +563,7 @@ static bool data_transfer_layersmapping_cdlayers_multisrc_to_dst(ListBase *r_map
         if (use_create) {
           /* Create as much data layers as necessary! */
           for (; idx_dst < idx_src; idx_dst++) {
-            CustomData_add_layer(cd_dst, cddata_type, CD_CALLOC, NULL, num_elem_dst);
+            CustomData_add_layer(cd_dst, cddata_type, CD_SET_DEFAULT, NULL, num_elem_dst);
           }
         }
         else {
@@ -624,7 +624,8 @@ static bool data_transfer_layersmapping_cdlayers_multisrc_to_dst(ListBase *r_map
 
         if ((idx_dst = CustomData_get_named_layer(cd_dst, cddata_type, name)) == -1) {
           if (use_create) {
-            CustomData_add_layer_named(cd_dst, cddata_type, CD_CALLOC, NULL, num_elem_dst, name);
+            CustomData_add_layer_named(
+                cd_dst, cddata_type, CD_SET_DEFAULT, NULL, num_elem_dst, name);
             idx_dst = CustomData_get_named_layer(cd_dst, cddata_type, name);
           }
           else {
@@ -712,7 +713,7 @@ static bool data_transfer_layersmapping_cdlayers(ListBase *r_map,
       if (!use_create) {
         return true;
       }
-      data_dst = CustomData_add_layer(cd_dst, cddata_type, CD_CALLOC, NULL, num_elem_dst);
+      data_dst = CustomData_add_layer(cd_dst, cddata_type, CD_SET_DEFAULT, NULL, num_elem_dst);
     }
     else if (use_dupref_dst && r_map) {
       /* If dest is a evaluated mesh (from modifier),
@@ -765,7 +766,7 @@ static bool data_transfer_layersmapping_cdlayers(ListBase *r_map,
         if (!use_create) {
           return true;
         }
-        data_dst = CustomData_add_layer(cd_dst, cddata_type, CD_CALLOC, NULL, num_elem_dst);
+        data_dst = CustomData_add_layer(cd_dst, cddata_type, CD_SET_DEFAULT, NULL, num_elem_dst);
       }
       else {
         /* If dest is a evaluated mesh (from modifier),
@@ -788,7 +789,7 @@ static bool data_transfer_layersmapping_cdlayers(ListBase *r_map,
         }
         /* Create as much data layers as necessary! */
         for (; num <= idx_dst; num++) {
-          CustomData_add_layer(cd_dst, cddata_type, CD_CALLOC, NULL, num_elem_dst);
+          CustomData_add_layer(cd_dst, cddata_type, CD_SET_DEFAULT, NULL, num_elem_dst);
         }
       }
       /* If dest is a evaluated mesh (from modifier),
@@ -807,7 +808,7 @@ static bool data_transfer_layersmapping_cdlayers(ListBase *r_map,
         if (!use_create) {
           return true;
         }
-        CustomData_add_layer_named(cd_dst, cddata_type, CD_CALLOC, NULL, num_elem_dst, name);
+        CustomData_add_layer_named(cd_dst, cddata_type, CD_SET_DEFAULT, NULL, num_elem_dst, name);
         idx_dst = CustomData_get_named_layer(cd_dst, cddata_type, name);
       }
       /* If dest is a evaluated mesh (from modifier),
@@ -927,38 +928,6 @@ static bool data_transfer_layersmapping_generate(ListBase *r_map,
       }
       return true;
     }
-    if (cddata_type == CD_FAKE_BWEIGHT) {
-      const size_t elem_size = sizeof(*((MVert *)NULL));
-      const size_t data_size = sizeof(((MVert *)NULL)->bweight);
-      const size_t data_offset = offsetof(MVert, bweight);
-      const uint64_t data_flag = 0;
-
-      if (!(me_src->cd_flag & ME_CDFLAG_VERT_BWEIGHT)) {
-        if (use_delete) {
-          me_dst->cd_flag &= ~ME_CDFLAG_VERT_BWEIGHT;
-        }
-        return true;
-      }
-      me_dst->cd_flag |= ME_CDFLAG_VERT_BWEIGHT;
-      if (r_map) {
-        data_transfer_layersmapping_add_item(r_map,
-                                             cddata_type,
-                                             mix_mode,
-                                             mix_factor,
-                                             mix_weights,
-                                             me_src->mvert,
-                                             me_dst->mvert,
-                                             me_src->totvert,
-                                             me_dst->totvert,
-                                             elem_size,
-                                             data_size,
-                                             data_offset,
-                                             data_flag,
-                                             data_transfer_interp_char,
-                                             interp_data);
-      }
-      return true;
-    }
     if (cddata_type == CD_FAKE_MDEFORMVERT) {
       bool ret;
 
@@ -979,9 +948,6 @@ static bool data_transfer_layersmapping_generate(ListBase *r_map,
                                                 me_dst != ob_dst->data,
                                                 fromlayers,
                                                 tolayers);
-
-      /* Mesh stores its dvert in a specific pointer too. :( */
-      me_dst->dvert = CustomData_get_layer(&me_dst->vdata, CD_MDEFORMVERT);
       return ret;
     }
     if (cddata_type == CD_FAKE_SHAPEKEY) {
@@ -1034,8 +1000,8 @@ static bool data_transfer_layersmapping_generate(ListBase *r_map,
                                              mix_mode,
                                              mix_factor,
                                              mix_weights,
-                                             me_src->medge,
-                                             me_dst->medge,
+                                             BKE_mesh_edges(me_src),
+                                             BKE_mesh_edges_for_write(me_dst),
                                              me_src->totedge,
                                              me_dst->totedge,
                                              elem_size,
@@ -1047,38 +1013,7 @@ static bool data_transfer_layersmapping_generate(ListBase *r_map,
       }
       return true;
     }
-    if (cddata_type == CD_FAKE_BWEIGHT) {
-      const size_t elem_size = sizeof(*((MEdge *)NULL));
-      const size_t data_size = sizeof(((MEdge *)NULL)->bweight);
-      const size_t data_offset = offsetof(MEdge, bweight);
-      const uint64_t data_flag = 0;
 
-      if (!(me_src->cd_flag & ME_CDFLAG_EDGE_BWEIGHT)) {
-        if (use_delete) {
-          me_dst->cd_flag &= ~ME_CDFLAG_EDGE_BWEIGHT;
-        }
-        return true;
-      }
-      me_dst->cd_flag |= ME_CDFLAG_EDGE_BWEIGHT;
-      if (r_map) {
-        data_transfer_layersmapping_add_item(r_map,
-                                             cddata_type,
-                                             mix_mode,
-                                             mix_factor,
-                                             mix_weights,
-                                             me_src->medge,
-                                             me_dst->medge,
-                                             me_src->totedge,
-                                             me_dst->totedge,
-                                             elem_size,
-                                             data_size,
-                                             data_offset,
-                                             data_flag,
-                                             data_transfer_interp_char,
-                                             interp_data);
-      }
-      return true;
-    }
     if (r_map && ELEM(cddata_type, CD_FAKE_SHARP, CD_FAKE_SEAM)) {
       const size_t elem_size = sizeof(*((MEdge *)NULL));
       const size_t data_size = sizeof(((MEdge *)NULL)->flag);
@@ -1090,8 +1025,8 @@ static bool data_transfer_layersmapping_generate(ListBase *r_map,
                                            mix_mode,
                                            mix_factor,
                                            mix_weights,
-                                           me_src->medge,
-                                           me_dst->medge,
+                                           BKE_mesh_edges(me_src),
+                                           BKE_mesh_edges_for_write(me_dst),
                                            me_src->totedge,
                                            me_dst->totedge,
                                            elem_size,
@@ -1184,8 +1119,8 @@ static bool data_transfer_layersmapping_generate(ListBase *r_map,
                                            mix_mode,
                                            mix_factor,
                                            mix_weights,
-                                           me_src->mpoly,
-                                           me_dst->mpoly,
+                                           BKE_mesh_polys(me_src),
+                                           BKE_mesh_polys_for_write(me_dst),
                                            me_src->totpoly,
                                            me_dst->totpoly,
                                            elem_size,
@@ -1410,7 +1345,7 @@ bool BKE_object_data_transfer_ex(struct Depsgraph *depsgraph,
   BKE_mesh_remap_calc_source_cddata_masks_from_map_modes(
       map_vert_mode, map_edge_mode, map_loop_mode, map_poly_mode, &me_src_mask);
   if (is_modifier) {
-    me_src = BKE_modifier_get_evaluated_mesh_from_evaluated_object(ob_src, false);
+    me_src = BKE_modifier_get_evaluated_mesh_from_evaluated_object(ob_src);
 
     if (me_src == NULL ||
         !CustomData_MeshMasks_are_matching(&ob_src->runtime.last_data_mask, &me_src_mask)) {
@@ -1432,7 +1367,7 @@ bool BKE_object_data_transfer_ex(struct Depsgraph *depsgraph,
     }
 
     BKE_mesh_remap_find_best_match_from_mesh(
-        me_dst->mvert, me_dst->totvert, me_src, space_transform);
+        BKE_mesh_verts(me_dst), me_dst->totvert, me_src, space_transform);
   }
 
   /* Check all possible data types.
@@ -1460,7 +1395,7 @@ bool BKE_object_data_transfer_ex(struct Depsgraph *depsgraph,
     }
 
     if (DT_DATATYPE_IS_VERT(dtdata_type)) {
-      MVert *verts_dst = me_dst->mvert;
+      MVert *verts_dst = BKE_mesh_verts_for_write(me_dst);
       const int num_verts_dst = me_dst->totvert;
 
       if (!geom_map_init[VDATA]) {
@@ -1542,9 +1477,9 @@ bool BKE_object_data_transfer_ex(struct Depsgraph *depsgraph,
       }
     }
     if (DT_DATATYPE_IS_EDGE(dtdata_type)) {
-      MVert *verts_dst = me_dst->mvert;
+      const MVert *verts_dst = BKE_mesh_verts_for_write(me_dst);
       const int num_verts_dst = me_dst->totvert;
-      MEdge *edges_dst = me_dst->medge;
+      const MEdge *edges_dst = BKE_mesh_edges(me_dst);
       const int num_edges_dst = me_dst->totedge;
 
       if (!geom_map_init[EDATA]) {
@@ -1621,13 +1556,13 @@ bool BKE_object_data_transfer_ex(struct Depsgraph *depsgraph,
       }
     }
     if (DT_DATATYPE_IS_LOOP(dtdata_type)) {
-      MVert *verts_dst = me_dst->mvert;
+      const MVert *verts_dst = BKE_mesh_verts(me_dst);
       const int num_verts_dst = me_dst->totvert;
-      MEdge *edges_dst = me_dst->medge;
+      const MEdge *edges_dst = BKE_mesh_edges(me_dst);
       const int num_edges_dst = me_dst->totedge;
-      MPoly *polys_dst = me_dst->mpoly;
+      const MPoly *polys_dst = BKE_mesh_polys(me_dst);
       const int num_polys_dst = me_dst->totpoly;
-      MLoop *loops_dst = me_dst->mloop;
+      const MLoop *loops_dst = BKE_mesh_loops(me_dst);
       const int num_loops_dst = me_dst->totloop;
       CustomData *ldata_dst = &me_dst->ldata;
 
@@ -1716,11 +1651,11 @@ bool BKE_object_data_transfer_ex(struct Depsgraph *depsgraph,
       }
     }
     if (DT_DATATYPE_IS_POLY(dtdata_type)) {
-      MVert *verts_dst = me_dst->mvert;
+      const MVert *verts_dst = BKE_mesh_verts(me_dst);
       const int num_verts_dst = me_dst->totvert;
-      MPoly *polys_dst = me_dst->mpoly;
+      const MPoly *polys_dst = BKE_mesh_polys(me_dst);
       const int num_polys_dst = me_dst->totpoly;
-      MLoop *loops_dst = me_dst->mloop;
+      const MLoop *loops_dst = BKE_mesh_loops(me_dst);
       const int num_loops_dst = me_dst->totloop;
 
       if (!geom_map_init[PDATA]) {
diff --git a/source/blender/blenkernel/intern/deform.c b/source/blender/blenkernel/intern/deform.c
index ebe06fa85eb..7940d65b1bb 100644
--- a/source/blender/blenkernel/intern/deform.c
+++ b/source/blender/blenkernel/intern/deform.c
@@ -94,10 +94,10 @@ bDeformGroup *BKE_defgroup_duplicate(const bDeformGroup *ingroup)
 void BKE_defvert_copy_subset(MDeformVert *dvert_dst,
                              const MDeformVert *dvert_src,
                              const bool *vgroup_subset,
-                             const int vgroup_tot)
+                             const int vgroup_num)
 {
   int defgroup;
-  for (defgroup = 0; defgroup < vgroup_tot; defgroup++) {
+  for (defgroup = 0; defgroup < vgroup_num; defgroup++) {
     if (vgroup_subset[defgroup]) {
       BKE_defvert_copy_index(dvert_dst, defgroup, dvert_src, defgroup);
     }
@@ -107,12 +107,12 @@ void BKE_defvert_copy_subset(MDeformVert *dvert_dst,
 void BKE_defvert_mirror_subset(MDeformVert *dvert_dst,
                                const MDeformVert *dvert_src,
                                const bool *vgroup_subset,
-                               const int vgroup_tot,
+                               const int vgroup_num,
                                const int *flip_map,
-                               const int flip_map_len)
+                               const int flip_map_num)
 {
   int defgroup;
-  for (defgroup = 0; defgroup < vgroup_tot && defgroup < flip_map_len; defgroup++) {
+  for (defgroup = 0; defgroup < vgroup_num && defgroup < flip_map_num; defgroup++) {
     if (vgroup_subset[defgroup] && (dvert_dst != dvert_src || flip_map[defgroup] != defgroup)) {
       BKE_defvert_copy_index(dvert_dst, flip_map[defgroup], dvert_src, defgroup);
     }
@@ -189,13 +189,13 @@ void BKE_defvert_sync(MDeformVert *dvert_dst, const MDeformVert *dvert_src, cons
 void BKE_defvert_sync_mapped(MDeformVert *dvert_dst,
                              const MDeformVert *dvert_src,
                              const int *flip_map,
-                             const int flip_map_len,
+                             const int flip_map_num,
                              const bool use_ensure)
 {
   if (dvert_src->totweight && dvert_dst->totweight) {
     MDeformWeight *dw_src = dvert_src->dw;
     for (int i = 0; i < dvert_src->totweight; i++, dw_src++) {
-      if (dw_src->def_nr < flip_map_len) {
+      if (dw_src->def_nr < flip_map_num) {
         MDeformWeight *dw_dst;
         if (use_ensure) {
           dw_dst = BKE_defvert_ensure_index(dvert_dst, flip_map[dw_src->def_nr]);
@@ -226,14 +226,14 @@ void BKE_defvert_remap(MDeformVert *dvert, const int *map, const int map_len)
 
 void BKE_defvert_normalize_subset(MDeformVert *dvert,
                                   const bool *vgroup_subset,
-                                  const int vgroup_tot)
+                                  const int vgroup_num)
 {
   if (dvert->totweight == 0) {
     /* nothing */
   }
   else if (dvert->totweight == 1) {
     MDeformWeight *dw = dvert->dw;
-    if ((dw->def_nr < vgroup_tot) && vgroup_subset[dw->def_nr]) {
+    if ((dw->def_nr < vgroup_num) && vgroup_subset[dw->def_nr]) {
       dw->weight = 1.0f;
     }
   }
@@ -241,7 +241,7 @@ void BKE_defvert_normalize_subset(MDeformVert *dvert,
     MDeformWeight *dw = dvert->dw;
     float tot_weight = 0.0f;
     for (int i = dvert->totweight; i != 0; i--, dw++) {
-      if ((dw->def_nr < vgroup_tot) && vgroup_subset[dw->def_nr]) {
+      if ((dw->def_nr < vgroup_num) && vgroup_subset[dw->def_nr]) {
         tot_weight += dw->weight;
       }
     }
@@ -250,7 +250,7 @@ void BKE_defvert_normalize_subset(MDeformVert *dvert,
       float scalar = 1.0f / tot_weight;
       dw = dvert->dw;
       for (int i = dvert->totweight; i != 0; i--, dw++) {
-        if ((dw->def_nr < vgroup_tot) && vgroup_subset[dw->def_nr]) {
+        if ((dw->def_nr < vgroup_num) && vgroup_subset[dw->def_nr]) {
           dw->weight *= scalar;
 
           /* in case of division errors with very low weights */
@@ -292,7 +292,7 @@ void BKE_defvert_normalize(MDeformVert *dvert)
 
 void BKE_defvert_normalize_lock_single(MDeformVert *dvert,
                                        const bool *vgroup_subset,
-                                       const int vgroup_tot,
+                                       const int vgroup_num,
                                        const uint def_nr_lock)
 {
   if (dvert->totweight == 0) {
@@ -300,7 +300,7 @@ void BKE_defvert_normalize_lock_single(MDeformVert *dvert,
   }
   else if (dvert->totweight == 1) {
     MDeformWeight *dw = dvert->dw;
-    if ((dw->def_nr < vgroup_tot) && vgroup_subset[dw->def_nr]) {
+    if ((dw->def_nr < vgroup_num) && vgroup_subset[dw->def_nr]) {
       if (def_nr_lock != dw->def_nr) {
         dw->weight = 1.0f;
       }
@@ -314,7 +314,7 @@ void BKE_defvert_normalize_lock_single(MDeformVert *dvert,
     float lock_iweight = 1.0f;
 
     for (i = dvert->totweight, dw = dvert->dw; i != 0; i--, dw++) {
-      if ((dw->def_nr < vgroup_tot) && vgroup_subset[dw->def_nr]) {
+      if ((dw->def_nr < vgroup_num) && vgroup_subset[dw->def_nr]) {
         if (dw->def_nr != def_nr_lock) {
           tot_weight += dw->weight;
         }
@@ -331,7 +331,7 @@ void BKE_defvert_normalize_lock_single(MDeformVert *dvert,
 
       float scalar = (1.0f / tot_weight) * lock_iweight;
       for (i = dvert->totweight, dw = dvert->dw; i != 0; i--, dw++) {
-        if ((dw->def_nr < vgroup_tot) && vgroup_subset[dw->def_nr]) {
+        if ((dw->def_nr < vgroup_num) && vgroup_subset[dw->def_nr]) {
           if (dw != dw_lock) {
             dw->weight *= scalar;
 
@@ -346,17 +346,17 @@ void BKE_defvert_normalize_lock_single(MDeformVert *dvert,
 
 void BKE_defvert_normalize_lock_map(MDeformVert *dvert,
                                     const bool *vgroup_subset,
-                                    const int vgroup_tot,
+                                    const int vgroup_num,
                                     const bool *lock_flags,
-                                    const int defbase_tot)
+                                    const int defbase_num)
 {
   if (dvert->totweight == 0) {
     /* nothing */
   }
   else if (dvert->totweight == 1) {
     MDeformWeight *dw = dvert->dw;
-    if ((dw->def_nr < vgroup_tot) && vgroup_subset[dw->def_nr]) {
-      if ((dw->def_nr < defbase_tot) && (lock_flags[dw->def_nr] == false)) {
+    if ((dw->def_nr < vgroup_num) && vgroup_subset[dw->def_nr]) {
+      if ((dw->def_nr < defbase_num) && (lock_flags[dw->def_nr] == false)) {
         dw->weight = 1.0f;
       }
     }
@@ -368,8 +368,8 @@ void BKE_defvert_normalize_lock_map(MDeformVert *dvert,
     float lock_iweight = 0.0f;
 
     for (i = dvert->totweight, dw = dvert->dw; i != 0; i--, dw++) {
-      if ((dw->def_nr < vgroup_tot) && vgroup_subset[dw->def_nr]) {
-        if ((dw->def_nr < defbase_tot) && (lock_flags[dw->def_nr] == false)) {
+      if ((dw->def_nr < vgroup_num) && vgroup_subset[dw->def_nr]) {
+        if ((dw->def_nr < defbase_num) && (lock_flags[dw->def_nr] == false)) {
           tot_weight += dw->weight;
         }
         else {
@@ -386,8 +386,8 @@ void BKE_defvert_normalize_lock_map(MDeformVert *dvert,
 
       float scalar = (1.0f / tot_weight) * lock_iweight;
       for (i = dvert->totweight, dw = dvert->dw; i != 0; i--, dw++) {
-        if ((dw->def_nr < vgroup_tot) && vgroup_subset[dw->def_nr]) {
-          if ((dw->def_nr < defbase_tot) && (lock_flags[dw->def_nr] == false)) {
+        if ((dw->def_nr < vgroup_num) && vgroup_subset[dw->def_nr]) {
+          if ((dw->def_nr < defbase_num) && (lock_flags[dw->def_nr] == false)) {
             dw->weight *= scalar;
 
             /* in case of division errors with very low weights */
@@ -399,13 +399,13 @@ void BKE_defvert_normalize_lock_map(MDeformVert *dvert,
   }
 }
 
-void BKE_defvert_flip(MDeformVert *dvert, const int *flip_map, const int flip_map_len)
+void BKE_defvert_flip(MDeformVert *dvert, const int *flip_map, const int flip_map_num)
 {
   MDeformWeight *dw;
   int i;
 
   for (dw = dvert->dw, i = 0; i < dvert->totweight; dw++, i++) {
-    if (dw->def_nr < flip_map_len) {
+    if (dw->def_nr < flip_map_num) {
       if (flip_map[dw->def_nr] >= 0) {
         dw->def_nr = flip_map[dw->def_nr];
       }
@@ -413,7 +413,7 @@ void BKE_defvert_flip(MDeformVert *dvert, const int *flip_map, const int flip_ma
   }
 }
 
-void BKE_defvert_flip_merged(MDeformVert *dvert, const int *flip_map, const int flip_map_len)
+void BKE_defvert_flip_merged(MDeformVert *dvert, const int *flip_map, const int flip_map_num)
 {
   MDeformWeight *dw, *dw_cpy;
   float weight;
@@ -421,7 +421,7 @@ void BKE_defvert_flip_merged(MDeformVert *dvert, const int *flip_map, const int
 
   /* copy weights */
   for (dw = dvert->dw, i = 0; i < totweight; dw++, i++) {
-    if (dw->def_nr < flip_map_len) {
+    if (dw->def_nr < flip_map_num) {
       if (flip_map[dw->def_nr] >= 0) {
         /* error checkers complain of this but we'll never get NULL return */
         dw_cpy = BKE_defvert_ensure_index(dvert, flip_map[dw->def_nr]);
@@ -572,20 +572,25 @@ void BKE_object_defgroup_active_index_set(Object *ob, const int new_index)
   *index = new_index;
 }
 
-int *BKE_object_defgroup_flip_map(const Object *ob, int *flip_map_len, const bool use_default)
+static int *object_defgroup_unlocked_flip_map_ex(const Object *ob,
+                                                 const bool use_default,
+                                                 const bool use_only_unlocked,
+                                                 int *r_flip_map_num)
 {
   const ListBase *defbase = BKE_object_defgroup_list(ob);
-  int defbase_tot = *flip_map_len = BLI_listbase_count(defbase);
+  const int defbase_num = BLI_listbase_count(defbase);
+  *r_flip_map_num = defbase_num;
 
-  if (defbase_tot == 0) {
+  if (defbase_num == 0) {
     return NULL;
   }
 
   bDeformGroup *dg;
   char name_flip[sizeof(dg->name)];
-  int i, flip_num, *map = MEM_mallocN(defbase_tot * sizeof(int), __func__);
+  int i, flip_num;
+  int *map = MEM_mallocN(defbase_num * sizeof(int), __func__);
 
-  for (i = 0; i < defbase_tot; i++) {
+  for (i = 0; i < defbase_num; i++) {
     map[i] = -1;
   }
 
@@ -597,11 +602,15 @@ int *BKE_object_defgroup_flip_map(const Object *ob, int *flip_map_len, const boo
         map[i] = i;
       }
 
+      if (use_only_unlocked && (dg->flag & DG_LOCK_WEIGHT)) {
+        continue;
+      }
+
       BLI_string_flip_side_name(name_flip, dg->name, false, sizeof(name_flip));
 
       if (!STREQ(name_flip, dg->name)) {
         flip_num = BKE_object_defgroup_name_index(ob, name_flip);
-        if (flip_num >= 0) {
+        if (flip_num != -1) {
           map[i] = flip_num;
           map[flip_num] = i; /* save an extra lookup */
         }
@@ -611,23 +620,36 @@ int *BKE_object_defgroup_flip_map(const Object *ob, int *flip_map_len, const boo
   return map;
 }
 
+int *BKE_object_defgroup_flip_map(const Object *ob, const bool use_default, int *r_flip_map_num)
+{
+  return object_defgroup_unlocked_flip_map_ex(ob, use_default, false, r_flip_map_num);
+}
+
+int *BKE_object_defgroup_flip_map_unlocked(const Object *ob,
+                                           const bool use_default,
+                                           int *r_flip_map_num)
+{
+  return object_defgroup_unlocked_flip_map_ex(ob, use_default, true, r_flip_map_num);
+}
+
 int *BKE_object_defgroup_flip_map_single(const Object *ob,
-                                         int *flip_map_len,
                                          const bool use_default,
-                                         int defgroup)
+                                         const int defgroup,
+                                         int *r_flip_map_num)
 {
   const ListBase *defbase = BKE_object_defgroup_list(ob);
-  int defbase_tot = *flip_map_len = BLI_listbase_count(defbase);
+  const int defbase_num = BLI_listbase_count(defbase);
+  *r_flip_map_num = defbase_num;
 
-  if (defbase_tot == 0) {
+  if (defbase_num == 0) {
     return NULL;
   }
 
   bDeformGroup *dg;
   char name_flip[sizeof(dg->name)];
-  int i, flip_num, *map = MEM_mallocN(defbase_tot * sizeof(int), __func__);
+  int i, flip_num, *map = MEM_mallocN(defbase_num * sizeof(int), __func__);
 
-  for (i = 0; i < defbase_tot; i++) {
+  for (i = 0; i < defbase_num; i++) {
     map[i] = use_default ? i : -1;
   }
 
@@ -776,7 +798,7 @@ MDeformWeight *BKE_defvert_ensure_index(MDeformVert *dvert, const int defgroup)
   return dw_new;
 }
 
-void BKE_defvert_add_index_notest(MDeformVert *dvert, int defgroup, const float weight)
+void BKE_defvert_add_index_notest(MDeformVert *dvert, const int defgroup, const float weight)
 {
   /* TODO: merge with #BKE_defvert_ensure_index! */
 
@@ -870,7 +892,7 @@ bool BKE_defvert_is_weight_zero(const struct MDeformVert *dvert, const int defgr
 }
 
 float BKE_defvert_total_selected_weight(const struct MDeformVert *dv,
-                                        int defbase_tot,
+                                        int defbase_num,
                                         const bool *defbase_sel)
 {
   float total = 0.0f;
@@ -881,7 +903,7 @@ float BKE_defvert_total_selected_weight(const struct MDeformVert *dv,
   }
 
   for (int i = dv->totweight; i != 0; i--, dw++) {
-    if (dw->def_nr < defbase_tot) {
+    if (dw->def_nr < defbase_num) {
       if (defbase_sel[dw->def_nr]) {
         total += dw->weight;
       }
@@ -892,17 +914,17 @@ float BKE_defvert_total_selected_weight(const struct MDeformVert *dv,
 }
 
 float BKE_defvert_multipaint_collective_weight(const struct MDeformVert *dv,
-                                               int defbase_tot,
+                                               const int defbase_num,
                                                const bool *defbase_sel,
-                                               int defbase_tot_sel,
-                                               bool is_normalized)
+                                               const int defbase_sel_num,
+                                               const bool is_normalized)
 {
-  float total = BKE_defvert_total_selected_weight(dv, defbase_tot, defbase_sel);
+  float total = BKE_defvert_total_selected_weight(dv, defbase_num, defbase_sel);
 
   /* in multipaint, get the average if auto normalize is inactive
    * get the sum if it is active */
   if (!is_normalized) {
-    total /= defbase_tot_sel;
+    total /= defbase_sel_num;
   }
 
   return total;
@@ -936,19 +958,19 @@ float BKE_defvert_calc_lock_relative_weight(float weight,
   return weight / (1.0f - locked_weight);
 }
 
-float BKE_defvert_lock_relative_weight(float weight,
+float BKE_defvert_lock_relative_weight(const float weight,
                                        const struct MDeformVert *dv,
-                                       int defbase_tot,
+                                       const int defbase_num,
                                        const bool *defbase_locked,
                                        const bool *defbase_unlocked)
 {
-  float unlocked = BKE_defvert_total_selected_weight(dv, defbase_tot, defbase_unlocked);
+  float unlocked = BKE_defvert_total_selected_weight(dv, defbase_num, defbase_unlocked);
 
   if (unlocked > 0.0f) {
     return weight / unlocked;
   }
 
-  float locked = BKE_defvert_total_selected_weight(dv, defbase_tot, defbase_locked);
+  float locked = BKE_defvert_total_selected_weight(dv, defbase_num, defbase_locked);
 
   return BKE_defvert_calc_lock_relative_weight(weight, locked, unlocked);
 }
@@ -1010,12 +1032,12 @@ void BKE_defvert_array_free(MDeformVert *dvert, int totvert)
 
 void BKE_defvert_extract_vgroup_to_vertweights(const MDeformVert *dvert,
                                                const int defgroup,
-                                               const int num_verts,
+                                               const int verts_num,
                                                const bool invert_vgroup,
                                                float *r_weights)
 {
   if (dvert && defgroup != -1) {
-    int i = num_verts;
+    int i = verts_num;
 
     while (i--) {
       const float w = BKE_defvert_find_weight(&dvert[i], defgroup);
@@ -1023,27 +1045,27 @@ void BKE_defvert_extract_vgroup_to_vertweights(const MDeformVert *dvert,
     }
   }
   else {
-    copy_vn_fl(r_weights, num_verts, invert_vgroup ? 1.0f : 0.0f);
+    copy_vn_fl(r_weights, verts_num, invert_vgroup ? 1.0f : 0.0f);
   }
 }
 
 void BKE_defvert_extract_vgroup_to_edgeweights(const MDeformVert *dvert,
                                                const int defgroup,
-                                               const int num_verts,
-                                               MEdge *edges,
-                                               const int num_edges,
+                                               const int verts_num,
+                                               const MEdge *edges,
+                                               const int edges_num,
                                                const bool invert_vgroup,
                                                float *r_weights)
 {
   if (dvert && defgroup != -1) {
-    int i = num_edges;
-    float *tmp_weights = MEM_mallocN(sizeof(*tmp_weights) * (size_t)num_verts, __func__);
+    int i = edges_num;
+    float *tmp_weights = MEM_mallocN(sizeof(*tmp_weights) * (size_t)verts_num, __func__);
 
     BKE_defvert_extract_vgroup_to_vertweights(
-        dvert, defgroup, num_verts, invert_vgroup, tmp_weights);
+        dvert, defgroup, verts_num, invert_vgroup, tmp_weights);
 
     while (i--) {
-      MEdge *me = &edges[i];
+      const MEdge *me = &edges[i];
 
       r_weights[i] = (tmp_weights[me->v1] + tmp_weights[me->v2]) * 0.5f;
     }
@@ -1051,27 +1073,27 @@ void BKE_defvert_extract_vgroup_to_edgeweights(const MDeformVert *dvert,
     MEM_freeN(tmp_weights);
   }
   else {
-    copy_vn_fl(r_weights, num_edges, 0.0f);
+    copy_vn_fl(r_weights, edges_num, 0.0f);
   }
 }
 
 void BKE_defvert_extract_vgroup_to_loopweights(const MDeformVert *dvert,
                                                const int defgroup,
-                                               const int num_verts,
-                                               MLoop *loops,
-                                               const int num_loops,
+                                               const int verts_num,
+                                               const MLoop *loops,
+                                               const int loops_num,
                                                const bool invert_vgroup,
                                                float *r_weights)
 {
   if (dvert && defgroup != -1) {
-    int i = num_loops;
-    float *tmp_weights = MEM_mallocN(sizeof(*tmp_weights) * (size_t)num_verts, __func__);
+    int i = loops_num;
+    float *tmp_weights = MEM_mallocN(sizeof(*tmp_weights) * (size_t)verts_num, __func__);
 
     BKE_defvert_extract_vgroup_to_vertweights(
-        dvert, defgroup, num_verts, invert_vgroup, tmp_weights);
+        dvert, defgroup, verts_num, invert_vgroup, tmp_weights);
 
     while (i--) {
-      MLoop *ml = &loops[i];
+      const MLoop *ml = &loops[i];
 
       r_weights[i] = tmp_weights[ml->v];
     }
@@ -1079,30 +1101,30 @@ void BKE_defvert_extract_vgroup_to_loopweights(const MDeformVert *dvert,
     MEM_freeN(tmp_weights);
   }
   else {
-    copy_vn_fl(r_weights, num_loops, 0.0f);
+    copy_vn_fl(r_weights, loops_num, 0.0f);
   }
 }
 
 void BKE_defvert_extract_vgroup_to_polyweights(const MDeformVert *dvert,
                                                const int defgroup,
-                                               const int num_verts,
-                                               MLoop *loops,
-                                               const int UNUSED(num_loops),
-                                               MPoly *polys,
-                                               const int num_polys,
+                                               const int verts_num,
+                                               const MLoop *loops,
+                                               const int UNUSED(loops_num),
+                                               const MPoly *polys,
+                                               const int polys_num,
                                                const bool invert_vgroup,
                                                float *r_weights)
 {
   if (dvert && defgroup != -1) {
-    int i = num_polys;
-    float *tmp_weights = MEM_mallocN(sizeof(*tmp_weights) * (size_t)num_verts, __func__);
+    int i = polys_num;
+    float *tmp_weights = MEM_mallocN(sizeof(*tmp_weights) * (size_t)verts_num, __func__);
 
     BKE_defvert_extract_vgroup_to_vertweights(
-        dvert, defgroup, num_verts, invert_vgroup, tmp_weights);
+        dvert, defgroup, verts_num, invert_vgroup, tmp_weights);
 
     while (i--) {
-      MPoly *mp = &polys[i];
-      MLoop *ml = &loops[mp->loopstart];
+      const MPoly *mp = &polys[i];
+      const MLoop *ml = &loops[mp->loopstart];
       int j = mp->totloop;
       float w = 0.0f;
 
@@ -1115,7 +1137,7 @@ void BKE_defvert_extract_vgroup_to_polyweights(const MDeformVert *dvert,
     MEM_freeN(tmp_weights);
   }
   else {
-    copy_vn_fl(r_weights, num_polys, 0.0f);
+    copy_vn_fl(r_weights, polys_num, 0.0f);
   }
 }
 
@@ -1207,7 +1229,7 @@ static bool data_transfer_layersmapping_vgroups_multisrc_to_dst(ListBase *r_map,
   const ListBase *src_list = BKE_object_defgroup_list(ob_src);
   ListBase *dst_defbase = BKE_object_defgroup_list_mutable(ob_dst);
 
-  int tot_dst = BLI_listbase_count(dst_defbase);
+  const int tot_dst = BLI_listbase_count(dst_defbase);
 
   const size_t elem_size = sizeof(*((MDeformVert *)NULL));
 
@@ -1243,7 +1265,8 @@ static bool data_transfer_layersmapping_vgroups_multisrc_to_dst(ListBase *r_map,
         /* At this stage, we **need** a valid CD_MDEFORMVERT layer on dest!
          * Again, use_create is not relevant in this case */
         if (!data_dst) {
-          data_dst = CustomData_add_layer(cd_dst, CD_MDEFORMVERT, CD_CALLOC, NULL, num_elem_dst);
+          data_dst = CustomData_add_layer(
+              cd_dst, CD_MDEFORMVERT, CD_SET_DEFAULT, NULL, num_elem_dst);
         }
 
         while (idx_src--) {
@@ -1303,7 +1326,8 @@ static bool data_transfer_layersmapping_vgroups_multisrc_to_dst(ListBase *r_map,
           /* At this stage, we **need** a valid CD_MDEFORMVERT layer on dest!
            * use_create is not relevant in this case */
           if (!data_dst) {
-            data_dst = CustomData_add_layer(cd_dst, CD_MDEFORMVERT, CD_CALLOC, NULL, num_elem_dst);
+            data_dst = CustomData_add_layer(
+                cd_dst, CD_MDEFORMVERT, CD_SET_DEFAULT, NULL, num_elem_dst);
           }
 
           data_transfer_layersmapping_add_item(r_map,
@@ -1442,7 +1466,8 @@ bool data_transfer_layersmapping_vgroups(ListBase *r_map,
       /* At this stage, we **need** a valid CD_MDEFORMVERT layer on dest!
        * use_create is not relevant in this case */
       if (!data_dst) {
-        data_dst = CustomData_add_layer(cd_dst, CD_MDEFORMVERT, CD_CALLOC, NULL, num_elem_dst);
+        data_dst = CustomData_add_layer(
+            cd_dst, CD_MDEFORMVERT, CD_SET_DEFAULT, NULL, num_elem_dst);
       }
 
       data_transfer_layersmapping_add_item(r_map,
diff --git a/source/blender/blenkernel/intern/displist.cc b/source/blender/blenkernel/intern/displist.cc
index 823fce52b50..279166297ec 100644
--- a/source/blender/blenkernel/intern/displist.cc
+++ b/source/blender/blenkernel/intern/displist.cc
@@ -34,10 +34,8 @@
 #include "BKE_displist.h"
 #include "BKE_geometry_set.hh"
 #include "BKE_key.h"
-#include "BKE_lattice.h"
 #include "BKE_lib_id.h"
 #include "BKE_mball.h"
-#include "BKE_mball_tessellate.h"
 #include "BKE_mesh.h"
 #include "BKE_modifier.h"
 #include "BKE_object.h"
@@ -86,133 +84,6 @@ DispList *BKE_displist_find(ListBase *lb, int type)
   return nullptr;
 }
 
-void BKE_displist_copy(ListBase *lbn, const ListBase *lb)
-{
-  BKE_displist_free(lbn);
-
-  LISTBASE_FOREACH (const DispList *, dl, lb) {
-    DispList *dln = (DispList *)MEM_dupallocN(dl);
-    BLI_addtail(lbn, dln);
-    dln->verts = (float *)MEM_dupallocN(dl->verts);
-    dln->nors = (float *)MEM_dupallocN(dl->nors);
-    dln->index = (int *)MEM_dupallocN(dl->index);
-  }
-}
-
-void BKE_displist_normals_add(ListBase *lb)
-{
-  float *vdata, *ndata, nor[3];
-  float *v1, *v2, *v3, *v4;
-  float *n1, *n2, *n3, *n4;
-  int a, b, p1, p2, p3, p4;
-
-  LISTBASE_FOREACH (DispList *, dl, lb) {
-    if (dl->type == DL_INDEX3) {
-      if (dl->nors == nullptr) {
-        dl->nors = (float *)MEM_callocN(sizeof(float[3]), __func__);
-
-        if (dl->flag & DL_BACK_CURVE) {
-          dl->nors[2] = -1.0f;
-        }
-        else {
-          dl->nors[2] = 1.0f;
-        }
-      }
-    }
-    else if (dl->type == DL_SURF) {
-      if (dl->nors == nullptr) {
-        dl->nors = (float *)MEM_callocN(sizeof(float[3]) * dl->nr * dl->parts, __func__);
-
-        vdata = dl->verts;
-        ndata = dl->nors;
-
-        for (a = 0; a < dl->parts; a++) {
-
-          if (BKE_displist_surfindex_get(dl, a, &b, &p1, &p2, &p3, &p4) == 0) {
-            break;
-          }
-
-          v1 = vdata + 3 * p1;
-          n1 = ndata + 3 * p1;
-          v2 = vdata + 3 * p2;
-          n2 = ndata + 3 * p2;
-          v3 = vdata + 3 * p3;
-          n3 = ndata + 3 * p3;
-          v4 = vdata + 3 * p4;
-          n4 = ndata + 3 * p4;
-
-          for (; b < dl->nr; b++) {
-            normal_quad_v3(nor, v1, v3, v4, v2);
-
-            add_v3_v3(n1, nor);
-            add_v3_v3(n2, nor);
-            add_v3_v3(n3, nor);
-            add_v3_v3(n4, nor);
-
-            v2 = v1;
-            v1 += 3;
-            v4 = v3;
-            v3 += 3;
-            n2 = n1;
-            n1 += 3;
-            n4 = n3;
-            n3 += 3;
-          }
-        }
-        a = dl->parts * dl->nr;
-        v1 = ndata;
-        while (a--) {
-          normalize_v3(v1);
-          v1 += 3;
-        }
-      }
-    }
-  }
-}
-
-void BKE_displist_count(const ListBase *lb, int *totvert, int *totface, int *tottri)
-{
-  LISTBASE_FOREACH (const DispList *, dl, lb) {
-    int vert_tot = 0;
-    int face_tot = 0;
-    int tri_tot = 0;
-    bool cyclic_u = dl->flag & DL_CYCL_U;
-    bool cyclic_v = dl->flag & DL_CYCL_V;
-
-    switch (dl->type) {
-      case DL_SURF: {
-        int segments_u = dl->nr - (cyclic_u == false);
-        int segments_v = dl->parts - (cyclic_v == false);
-        vert_tot = dl->nr * dl->parts;
-        face_tot = segments_u * segments_v;
-        tri_tot = face_tot * 2;
-        break;
-      }
-      case DL_INDEX3: {
-        vert_tot = dl->nr;
-        face_tot = dl->parts;
-        tri_tot = face_tot;
-        break;
-      }
-      case DL_INDEX4: {
-        vert_tot = dl->nr;
-        face_tot = dl->parts;
-        tri_tot = face_tot * 2;
-        break;
-      }
-      case DL_POLY:
-      case DL_SEGM: {
-        vert_tot = dl->nr * dl->parts;
-        break;
-      }
-    }
-
-    *totvert += vert_tot;
-    *totface += face_tot;
-    *tottri += tri_tot;
-  }
-}
-
 bool BKE_displist_surfindex_get(
     const DispList *dl, int a, int *b, int *p1, int *p2, int *p3, int *p4)
 {
@@ -243,7 +114,6 @@ bool BKE_displist_surfindex_get(
   return true;
 }
 
-/* ****************** Make #DispList ********************* */
 #ifdef __INTEL_COMPILER
 /* ICC with the optimization -02 causes crashes. */
 #  pragma intel optimization_level 1
@@ -638,27 +508,6 @@ float BKE_displist_calc_taper(
   return displist_calc_taper(depsgraph, scene, taperobj, fac);
 }
 
-void BKE_displist_make_mball(Depsgraph *depsgraph, Scene *scene, Object *ob)
-{
-  if (!ob || ob->type != OB_MBALL) {
-    return;
-  }
-
-  if (ob == BKE_mball_basis_find(scene, ob)) {
-    if (ob->runtime.curve_cache) {
-      BKE_displist_free(&(ob->runtime.curve_cache->disp));
-    }
-    else {
-      ob->runtime.curve_cache = MEM_cnew(__func__);
-    }
-
-    BKE_mball_polygonize(depsgraph, scene, ob, &ob->runtime.curve_cache->disp);
-    BKE_mball_texspace_calc(ob);
-
-    object_deform_mball(ob, &ob->runtime.curve_cache->disp);
-  }
-}
-
 static ModifierData *curve_get_tessellate_point(const Scene *scene,
                                                 const Object *ob,
                                                 const bool for_render,
@@ -785,7 +634,7 @@ void BKE_curve_calc_modifiers_pre(Depsgraph *depsgraph,
 
 /**
  * \return True if the deformed curve control point data should be implicitly
- * converted directly to a mesh, or false if it can be left as curve data via #CurveEval.
+ * converted directly to a mesh, or false if it can be left as curve data via the #Curves type.
  */
 static bool do_curve_implicit_mesh_conversion(const Curve *curve,
                                               ModifierData *first_modifier,
@@ -1493,7 +1342,7 @@ void BKE_displist_make_curveTypes(Depsgraph *depsgraph,
        * - The dependency graph has handling of edit mode pointers (see #update_edit_mode_pointers)
        *   but it doesn't seem to work in this case.
        *
-       * Since the the plan is to replace this legacy curve object with the curves data-block
+       * Since the plan is to replace this legacy curve object with the curves data-block
        * (see T95355), this somewhat hacky inefficient solution is relatively temporary.
        */
       Curve &cow_curve = *reinterpret_cast(
@@ -1514,20 +1363,19 @@ void BKE_displist_make_curveTypes(Depsgraph *depsgraph,
 
 void BKE_displist_minmax(const ListBase *dispbase, float min[3], float max[3])
 {
-  bool doit = false;
+  bool empty = true;
 
   LISTBASE_FOREACH (const DispList *, dl, dispbase) {
-    const int tot = (ELEM(dl->type, DL_INDEX3, DL_INDEX4)) ? dl->nr : dl->nr * dl->parts;
+    const int tot = dl->type == DL_INDEX3 ? dl->nr : dl->nr * dl->parts;
     for (const int i : IndexRange(tot)) {
       minmax_v3v3_v3(min, max, &dl->verts[i * 3]);
     }
     if (tot != 0) {
-      doit = true;
+      empty = false;
     }
   }
 
-  if (!doit) {
-    /* there's no geometry in displist, use zero-sized boundbox */
+  if (empty) {
     zero_v3(min);
     zero_v3(max);
   }
diff --git a/source/blender/blenkernel/intern/dynamicpaint.c b/source/blender/blenkernel/intern/dynamicpaint.c
index 423e76fce8c..9d46c381d7a 100644
--- a/source/blender/blenkernel/intern/dynamicpaint.c
+++ b/source/blender/blenkernel/intern/dynamicpaint.c
@@ -1402,24 +1402,24 @@ static void dynamicPaint_initAdjacencyData(DynamicPaintSurface *surface, const b
     /* For vertex format, count every vertex that is connected by an edge */
     int numOfEdges = mesh->totedge;
     int numOfPolys = mesh->totpoly;
-    struct MEdge *edge = mesh->medge;
-    struct MPoly *mpoly = mesh->mpoly;
-    struct MLoop *mloop = mesh->mloop;
+    const MEdge *edges = BKE_mesh_edges(mesh);
+    const MPoly *polys = BKE_mesh_polys(mesh);
+    const MLoop *loops = BKE_mesh_loops(mesh);
 
     /* count number of edges per vertex */
     for (int i = 0; i < numOfEdges; i++) {
-      ad->n_num[edge[i].v1]++;
-      ad->n_num[edge[i].v2]++;
+      ad->n_num[edges[i].v1]++;
+      ad->n_num[edges[i].v2]++;
 
-      temp_data[edge[i].v1]++;
-      temp_data[edge[i].v2]++;
+      temp_data[edges[i].v1]++;
+      temp_data[edges[i].v2]++;
     }
 
     /* also add number of vertices to temp_data
      * to locate points on "mesh edge" */
     for (int i = 0; i < numOfPolys; i++) {
-      for (int j = 0; j < mpoly[i].totloop; j++) {
-        temp_data[mloop[mpoly[i].loopstart + j].v]++;
+      for (int j = 0; j < polys[i].totloop; j++) {
+        temp_data[loops[polys[i].loopstart + j].v]++;
       }
     }
 
@@ -1444,15 +1444,15 @@ static void dynamicPaint_initAdjacencyData(DynamicPaintSurface *surface, const b
     /* and now add neighbor data using that info */
     for (int i = 0; i < numOfEdges; i++) {
       /* first vertex */
-      int index = edge[i].v1;
+      int index = edges[i].v1;
       n_pos = ad->n_index[index] + temp_data[index];
-      ad->n_target[n_pos] = edge[i].v2;
+      ad->n_target[n_pos] = edges[i].v2;
       temp_data[index]++;
 
       /* second vertex */
-      index = edge[i].v2;
+      index = edges[i].v2;
       n_pos = ad->n_index[index] + temp_data[index];
-      ad->n_target[n_pos] = edge[i].v1;
+      ad->n_target[n_pos] = edges[i].v1;
       temp_data[index]++;
     }
   }
@@ -1604,7 +1604,7 @@ static void dynamicPaint_setInitialColor(const Scene *scene, DynamicPaintSurface
   else if (surface->init_color_type == MOD_DPAINT_INITIAL_TEXTURE) {
     Tex *tex = surface->init_texture;
 
-    const MLoop *mloop = mesh->mloop;
+    const MLoop *mloop = BKE_mesh_loops(mesh);
     const MLoopTri *mlooptri = BKE_mesh_runtime_looptri_ensure(mesh);
     const int tottri = BKE_mesh_runtime_looptri_len(mesh);
 
@@ -1660,7 +1660,7 @@ static void dynamicPaint_setInitialColor(const Scene *scene, DynamicPaintSurface
 
     /* for vertex surface, just copy colors from mcol */
     if (surface->format == MOD_DPAINT_SURFACE_F_VERTEX) {
-      const MLoop *mloop = mesh->mloop;
+      const MLoop *mloop = BKE_mesh_loops(mesh);
       const int totloop = mesh->totloop;
       const MLoopCol *col = CustomData_get_layer_named(
           &mesh->ldata, CD_PROP_BYTE_COLOR, surface->init_layername);
@@ -1811,7 +1811,7 @@ static void dynamicPaint_applySurfaceDisplace(DynamicPaintSurface *surface, Mesh
 
   /* displace paint */
   if (surface->type == MOD_DPAINT_SURFACE_T_DISPLACE) {
-    MVert *mvert = result->mvert;
+    MVert *mvert = BKE_mesh_verts_for_write(result);
 
     DynamicPaintModifierApplyData data = {
         .surface = surface,
@@ -1913,9 +1913,9 @@ static Mesh *dynamicPaint_Modifier_apply(DynamicPaintModifierData *pmd, Object *
 
           /* vertex color paint */
           if (surface->type == MOD_DPAINT_SURFACE_T_PAINT) {
-            MLoop *mloop = result->mloop;
+            const MLoop *mloop = BKE_mesh_loops(result);
             const int totloop = result->totloop;
-            MPoly *mpoly = result->mpoly;
+            const MPoly *mpoly = BKE_mesh_polys(result);
             const int totpoly = result->totpoly;
 
             /* paint is stored on dry and wet layers, so mix final color first */
@@ -1944,7 +1944,7 @@ static Mesh *dynamicPaint_Modifier_apply(DynamicPaintModifierData *pmd, Object *
             if (!mloopcol && dynamicPaint_outputLayerExists(surface, ob, 0)) {
               mloopcol = CustomData_add_layer_named(&result->ldata,
                                                     CD_PROP_BYTE_COLOR,
-                                                    CD_CALLOC,
+                                                    CD_SET_DEFAULT,
                                                     NULL,
                                                     totloop,
                                                     surface->output_name);
@@ -1957,7 +1957,7 @@ static Mesh *dynamicPaint_Modifier_apply(DynamicPaintModifierData *pmd, Object *
             if (!mloopcol_wet && dynamicPaint_outputLayerExists(surface, ob, 1)) {
               mloopcol_wet = CustomData_add_layer_named(&result->ldata,
                                                         CD_PROP_BYTE_COLOR,
-                                                        CD_CALLOC,
+                                                        CD_SET_DEFAULT,
                                                         NULL,
                                                         totloop,
                                                         surface->output_name2);
@@ -1988,9 +1988,7 @@ static Mesh *dynamicPaint_Modifier_apply(DynamicPaintModifierData *pmd, Object *
             /* apply weights into a vertex group, if doesn't exists add a new layer */
             if (defgrp_index != -1 && !dvert && (surface->output_name[0] != '\0')) {
               dvert = CustomData_add_layer(
-                  &result->vdata, CD_MDEFORMVERT, CD_CALLOC, NULL, sData->total_points);
-              /* Make the dvert layer easily accessible from the mesh data. */
-              result->dvert = dvert;
+                  &result->vdata, CD_MDEFORMVERT, CD_SET_DEFAULT, NULL, sData->total_points);
             }
             if (defgrp_index != -1 && dvert) {
               for (int i = 0; i < sData->total_points; i++) {
@@ -2012,7 +2010,7 @@ static Mesh *dynamicPaint_Modifier_apply(DynamicPaintModifierData *pmd, Object *
           }
           /* wave simulation */
           else if (surface->type == MOD_DPAINT_SURFACE_T_WAVE) {
-            MVert *mvert = result->mvert;
+            MVert *mvert = BKE_mesh_verts_for_write(result);
 
             DynamicPaintModifierApplyData data = {
                 .surface = surface,
@@ -2823,7 +2821,7 @@ int dynamicPaint_createUVSurface(Scene *scene,
     return setError(canvas, N_("Cannot bake non-'image sequence' formats"));
   }
 
-  mloop = mesh->mloop;
+  mloop = BKE_mesh_loops(mesh);
   mlooptri = BKE_mesh_runtime_looptri_ensure(mesh);
   const int tottri = BKE_mesh_runtime_looptri_len(mesh);
 
@@ -2963,7 +2961,7 @@ int dynamicPaint_createUVSurface(Scene *scene,
 
         BKE_mesh_vert_looptri_map_create(&vert_to_looptri_map,
                                          &vert_to_looptri_map_mem,
-                                         mesh->mvert,
+                                         BKE_mesh_verts_for_write(mesh),
                                          mesh->totvert,
                                          mlooptri,
                                          tottri,
@@ -3783,7 +3781,8 @@ static void dynamicPaint_brushMeshCalculateVelocity(Depsgraph *depsgraph,
                                       eModifierType_DynamicPaint);
   mesh_p = BKE_mesh_copy_for_eval(dynamicPaint_brush_mesh_get(brush), false);
   numOfVerts_p = mesh_p->totvert;
-  mvert_p = mesh_p->mvert;
+
+  mvert_p = BKE_mesh_verts_for_write(mesh_p);
   copy_m4_m4(prev_obmat, ob->obmat);
 
   /* current frame mesh */
@@ -3799,7 +3798,7 @@ static void dynamicPaint_brushMeshCalculateVelocity(Depsgraph *depsgraph,
                                       eModifierType_DynamicPaint);
   mesh_c = dynamicPaint_brush_mesh_get(brush);
   numOfVerts_c = mesh_c->totvert;
-  mvert_c = mesh_c->mvert;
+  mvert_c = BKE_mesh_verts_for_write(mesh_c);
 
   (*brushVel) = (struct Vec3f *)MEM_mallocN(numOfVerts_c * sizeof(Vec3f),
                                             "Dynamic Paint brush velocity");
@@ -4270,10 +4269,10 @@ static bool dynamicPaint_paintMesh(Depsgraph *depsgraph,
     VolumeGrid *grid = bData->grid;
 
     mesh = BKE_mesh_copy_for_eval(brush_mesh, false);
-    mvert = mesh->mvert;
+    mvert = BKE_mesh_verts_for_write(mesh);
     const float(*vert_normals)[3] = BKE_mesh_vertex_normals_ensure(mesh);
     mlooptri = BKE_mesh_runtime_looptri_ensure(mesh);
-    mloop = mesh->mloop;
+    mloop = BKE_mesh_loops(mesh);
     numOfVerts = mesh->totvert;
 
     /* Transform collider vertices to global space
@@ -4759,7 +4758,7 @@ static bool dynamicPaint_paintSinglePoint(
   }
 
   const Mesh *brush_mesh = dynamicPaint_brush_mesh_get(brush);
-  const MVert *mvert = brush_mesh->mvert;
+  const MVert *mvert = BKE_mesh_verts(brush_mesh);
 
   /*
    * Loop through every surface point
@@ -5862,7 +5861,7 @@ static bool dynamicPaint_surfaceHasMoved(DynamicPaintSurface *surface, Object *o
   PaintSurfaceData *sData = surface->data;
   PaintBakeData *bData = sData->bData;
   Mesh *mesh = dynamicPaint_canvas_mesh_get(surface->canvas);
-  MVert *mvert = mesh->mvert;
+  const MVert *mvert = BKE_mesh_verts(mesh);
 
   int numOfVerts = mesh->totvert;
 
@@ -6022,7 +6021,7 @@ static bool dynamicPaint_generateBakeData(DynamicPaintSurface *surface,
   const bool do_accel_data = (surface->effect & MOD_DPAINT_EFFECT_DO_DRIP) != 0;
 
   int canvasNumOfVerts = mesh->totvert;
-  MVert *mvert = mesh->mvert;
+  const MVert *mvert = BKE_mesh_verts(mesh);
   Vec3f *canvas_verts;
 
   if (bData) {
diff --git a/source/blender/blenkernel/intern/editmesh_tangent.c b/source/blender/blenkernel/intern/editmesh_tangent.c
deleted file mode 100644
index 0a3107eee24..00000000000
--- a/source/blender/blenkernel/intern/editmesh_tangent.c
+++ /dev/null
@@ -1,434 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-
-/** \file
- * \ingroup bke
- */
-
-#include "BLI_math.h"
-#include "BLI_task.h"
-
-#include "DNA_customdata_types.h"
-#include "DNA_defs.h"
-#include "DNA_meshdata_types.h"
-
-#include "BKE_customdata.h"
-#include "BKE_editmesh.h"
-#include "BKE_editmesh_tangent.h"
-#include "BKE_mesh.h"
-#include "BKE_mesh_tangent.h" /* for utility functions */
-
-#include "MEM_guardedalloc.h"
-
-/* interface */
-#include "mikktspace.h"
-
-/* -------------------------------------------------------------------- */
-/** \name Tangent Space Calculation
- * \{ */
-
-/* Necessary complexity to handle looptri's as quads for correct tangents */
-#define USE_LOOPTRI_DETECT_QUADS
-
-typedef struct {
-  const float (*precomputedFaceNormals)[3];
-  const float (*precomputedLoopNormals)[3];
-  const BMLoop *(*looptris)[3];
-  int cd_loop_uv_offset; /* texture coordinates */
-  const float (*orco)[3];
-  float (*tangent)[4]; /* destination */
-  int numTessFaces;
-
-#ifdef USE_LOOPTRI_DETECT_QUADS
-  /* map from 'fake' face index to looptri,
-   * quads will point to the first looptri of the quad */
-  const int *face_as_quad_map;
-  int num_face_as_quad_map;
-#endif
-
-} SGLSLEditMeshToTangent;
-
-#ifdef USE_LOOPTRI_DETECT_QUADS
-/* seems weak but only used on quads */
-static const BMLoop *bm_loop_at_face_index(const BMFace *f, int vert_index)
-{
-  const BMLoop *l = BM_FACE_FIRST_LOOP(f);
-  while (vert_index--) {
-    l = l->next;
-  }
-  return l;
-}
-#endif
-
-static int emdm_ts_GetNumFaces(const SMikkTSpaceContext *pContext)
-{
-  SGLSLEditMeshToTangent *pMesh = pContext->m_pUserData;
-
-#ifdef USE_LOOPTRI_DETECT_QUADS
-  return pMesh->num_face_as_quad_map;
-#else
-  return pMesh->numTessFaces;
-#endif
-}
-
-static int emdm_ts_GetNumVertsOfFace(const SMikkTSpaceContext *pContext, const int face_num)
-{
-#ifdef USE_LOOPTRI_DETECT_QUADS
-  SGLSLEditMeshToTangent *pMesh = pContext->m_pUserData;
-  if (pMesh->face_as_quad_map) {
-    const BMLoop **lt = pMesh->looptris[pMesh->face_as_quad_map[face_num]];
-    if (lt[0]->f->len == 4) {
-      return 4;
-    }
-  }
-  return 3;
-#else
-  UNUSED_VARS(pContext, face_num);
-  return 3;
-#endif
-}
-
-static void emdm_ts_GetPosition(const SMikkTSpaceContext *pContext,
-                                float r_co[3],
-                                const int face_num,
-                                const int vert_index)
-{
-  // BLI_assert(vert_index >= 0 && vert_index < 4);
-  SGLSLEditMeshToTangent *pMesh = pContext->m_pUserData;
-  const BMLoop **lt;
-  const BMLoop *l;
-
-#ifdef USE_LOOPTRI_DETECT_QUADS
-  if (pMesh->face_as_quad_map) {
-    lt = pMesh->looptris[pMesh->face_as_quad_map[face_num]];
-    if (lt[0]->f->len == 4) {
-      l = bm_loop_at_face_index(lt[0]->f, vert_index);
-      goto finally;
-    }
-    /* fall through to regular triangle */
-  }
-  else {
-    lt = pMesh->looptris[face_num];
-  }
-#else
-  lt = pMesh->looptris[face_num];
-#endif
-  l = lt[vert_index];
-
-  const float *co;
-
-finally:
-  co = l->v->co;
-  copy_v3_v3(r_co, co);
-}
-
-static void emdm_ts_GetTextureCoordinate(const SMikkTSpaceContext *pContext,
-                                         float r_uv[2],
-                                         const int face_num,
-                                         const int vert_index)
-{
-  // BLI_assert(vert_index >= 0 && vert_index < 4);
-  SGLSLEditMeshToTangent *pMesh = pContext->m_pUserData;
-  const BMLoop **lt;
-  const BMLoop *l;
-
-#ifdef USE_LOOPTRI_DETECT_QUADS
-  if (pMesh->face_as_quad_map) {
-    lt = pMesh->looptris[pMesh->face_as_quad_map[face_num]];
-    if (lt[0]->f->len == 4) {
-      l = bm_loop_at_face_index(lt[0]->f, vert_index);
-      goto finally;
-    }
-    /* fall through to regular triangle */
-  }
-  else {
-    lt = pMesh->looptris[face_num];
-  }
-#else
-  lt = pMesh->looptris[face_num];
-#endif
-  l = lt[vert_index];
-
-finally:
-  if (pMesh->cd_loop_uv_offset != -1) {
-    const float *uv = BM_ELEM_CD_GET_VOID_P(l, pMesh->cd_loop_uv_offset);
-    copy_v2_v2(r_uv, uv);
-  }
-  else {
-    const float *orco = pMesh->orco[BM_elem_index_get(l->v)];
-    map_to_sphere(&r_uv[0], &r_uv[1], orco[0], orco[1], orco[2]);
-  }
-}
-
-static void emdm_ts_GetNormal(const SMikkTSpaceContext *pContext,
-                              float r_no[3],
-                              const int face_num,
-                              const int vert_index)
-{
-  // BLI_assert(vert_index >= 0 && vert_index < 4);
-  SGLSLEditMeshToTangent *pMesh = pContext->m_pUserData;
-  const BMLoop **lt;
-  const BMLoop *l;
-
-#ifdef USE_LOOPTRI_DETECT_QUADS
-  if (pMesh->face_as_quad_map) {
-    lt = pMesh->looptris[pMesh->face_as_quad_map[face_num]];
-    if (lt[0]->f->len == 4) {
-      l = bm_loop_at_face_index(lt[0]->f, vert_index);
-      goto finally;
-    }
-    /* fall through to regular triangle */
-  }
-  else {
-    lt = pMesh->looptris[face_num];
-  }
-#else
-  lt = pMesh->looptris[face_num];
-#endif
-  l = lt[vert_index];
-
-finally:
-  if (pMesh->precomputedLoopNormals) {
-    copy_v3_v3(r_no, pMesh->precomputedLoopNormals[BM_elem_index_get(l)]);
-  }
-  else if (BM_elem_flag_test(l->f, BM_ELEM_SMOOTH) == 0) { /* flat */
-    if (pMesh->precomputedFaceNormals) {
-      copy_v3_v3(r_no, pMesh->precomputedFaceNormals[BM_elem_index_get(l->f)]);
-    }
-    else {
-      copy_v3_v3(r_no, l->f->no);
-    }
-  }
-  else {
-    copy_v3_v3(r_no, l->v->no);
-  }
-}
-
-static void emdm_ts_SetTSpace(const SMikkTSpaceContext *pContext,
-                              const float fvTangent[3],
-                              const float fSign,
-                              const int face_num,
-                              const int vert_index)
-{
-  // BLI_assert(vert_index >= 0 && vert_index < 4);
-  SGLSLEditMeshToTangent *pMesh = pContext->m_pUserData;
-  const BMLoop **lt;
-  const BMLoop *l;
-
-#ifdef USE_LOOPTRI_DETECT_QUADS
-  if (pMesh->face_as_quad_map) {
-    lt = pMesh->looptris[pMesh->face_as_quad_map[face_num]];
-    if (lt[0]->f->len == 4) {
-      l = bm_loop_at_face_index(lt[0]->f, vert_index);
-      goto finally;
-    }
-    /* fall through to regular triangle */
-  }
-  else {
-    lt = pMesh->looptris[face_num];
-  }
-#else
-  lt = pMesh->looptris[face_num];
-#endif
-  l = lt[vert_index];
-
-  float *pRes;
-
-finally:
-  pRes = pMesh->tangent[BM_elem_index_get(l)];
-  copy_v3_v3(pRes, fvTangent);
-  pRes[3] = fSign;
-}
-
-static void emDM_calc_loop_tangents_thread(TaskPool *__restrict UNUSED(pool), void *taskdata)
-{
-  struct SGLSLEditMeshToTangent *mesh2tangent = taskdata;
-  /* new computation method */
-  {
-    SMikkTSpaceContext sContext = {NULL};
-    SMikkTSpaceInterface sInterface = {NULL};
-    sContext.m_pUserData = mesh2tangent;
-    sContext.m_pInterface = &sInterface;
-    sInterface.m_getNumFaces = emdm_ts_GetNumFaces;
-    sInterface.m_getNumVerticesOfFace = emdm_ts_GetNumVertsOfFace;
-    sInterface.m_getPosition = emdm_ts_GetPosition;
-    sInterface.m_getTexCoord = emdm_ts_GetTextureCoordinate;
-    sInterface.m_getNormal = emdm_ts_GetNormal;
-    sInterface.m_setTSpaceBasic = emdm_ts_SetTSpace;
-    /* 0 if failed */
-    genTangSpaceDefault(&sContext);
-  }
-}
-
-void BKE_editmesh_loop_tangent_calc(BMEditMesh *em,
-                                    bool calc_active_tangent,
-                                    const char (*tangent_names)[MAX_NAME],
-                                    int tangent_names_len,
-                                    const float (*poly_normals)[3],
-                                    const float (*loop_normals)[3],
-                                    const float (*vert_orco)[3],
-                                    /* result */
-                                    CustomData *loopdata_out,
-                                    const uint loopdata_out_len,
-                                    short *tangent_mask_curr_p)
-{
-  BMesh *bm = em->bm;
-
-  int act_uv_n = -1;
-  int ren_uv_n = -1;
-  bool calc_act = false;
-  bool calc_ren = false;
-  char act_uv_name[MAX_NAME];
-  char ren_uv_name[MAX_NAME];
-  short tangent_mask = 0;
-  short tangent_mask_curr = *tangent_mask_curr_p;
-
-  BKE_mesh_calc_loop_tangent_step_0(&bm->ldata,
-                                    calc_active_tangent,
-                                    tangent_names,
-                                    tangent_names_len,
-                                    &calc_act,
-                                    &calc_ren,
-                                    &act_uv_n,
-                                    &ren_uv_n,
-                                    act_uv_name,
-                                    ren_uv_name,
-                                    &tangent_mask);
-
-  if ((tangent_mask_curr | tangent_mask) != tangent_mask_curr) {
-    for (int i = 0; i < tangent_names_len; i++) {
-      if (tangent_names[i][0]) {
-        BKE_mesh_add_loop_tangent_named_layer_for_uv(
-            &bm->ldata, loopdata_out, (int)loopdata_out_len, tangent_names[i]);
-      }
-    }
-    if ((tangent_mask & DM_TANGENT_MASK_ORCO) &&
-        CustomData_get_named_layer_index(loopdata_out, CD_TANGENT, "") == -1) {
-      CustomData_add_layer_named(
-          loopdata_out, CD_TANGENT, CD_CALLOC, NULL, (int)loopdata_out_len, "");
-    }
-    if (calc_act && act_uv_name[0]) {
-      BKE_mesh_add_loop_tangent_named_layer_for_uv(
-          &bm->ldata, loopdata_out, (int)loopdata_out_len, act_uv_name);
-    }
-    if (calc_ren && ren_uv_name[0]) {
-      BKE_mesh_add_loop_tangent_named_layer_for_uv(
-          &bm->ldata, loopdata_out, (int)loopdata_out_len, ren_uv_name);
-    }
-    int totface = em->tottri;
-#ifdef USE_LOOPTRI_DETECT_QUADS
-    int num_face_as_quad_map;
-    int *face_as_quad_map = NULL;
-
-    /* map faces to quads */
-    if (em->tottri != bm->totface) {
-      /* Over allocate, since we don't know how many ngon or quads we have. */
-
-      /* map fake face index to looptri */
-      face_as_quad_map = MEM_mallocN(sizeof(int) * totface, __func__);
-      int i, j;
-      for (i = 0, j = 0; j < totface; i++, j++) {
-        face_as_quad_map[i] = j;
-        /* step over all quads */
-        if (em->looptris[j][0]->f->len == 4) {
-          j++; /* skips the nest looptri */
-        }
-      }
-      num_face_as_quad_map = i;
-    }
-    else {
-      num_face_as_quad_map = totface;
-    }
-#endif
-    /* Calculation */
-    if (em->tottri != 0) {
-      TaskPool *task_pool;
-      task_pool = BLI_task_pool_create(NULL, TASK_PRIORITY_HIGH);
-
-      tangent_mask_curr = 0;
-      /* Calculate tangent layers */
-      SGLSLEditMeshToTangent data_array[MAX_MTFACE];
-      int index = 0;
-      int n = 0;
-      CustomData_update_typemap(loopdata_out);
-      const int tangent_layer_num = CustomData_number_of_layers(loopdata_out, CD_TANGENT);
-      for (n = 0; n < tangent_layer_num; n++) {
-        index = CustomData_get_layer_index_n(loopdata_out, CD_TANGENT, n);
-        BLI_assert(n < MAX_MTFACE);
-        SGLSLEditMeshToTangent *mesh2tangent = &data_array[n];
-        mesh2tangent->numTessFaces = em->tottri;
-#ifdef USE_LOOPTRI_DETECT_QUADS
-        mesh2tangent->face_as_quad_map = face_as_quad_map;
-        mesh2tangent->num_face_as_quad_map = num_face_as_quad_map;
-#endif
-        mesh2tangent->precomputedFaceNormals = poly_normals;
-        /* NOTE: we assume we do have tessellated loop normals at this point
-         * (in case it is object-enabled), have to check this is valid. */
-        mesh2tangent->precomputedLoopNormals = loop_normals;
-        mesh2tangent->cd_loop_uv_offset = CustomData_get_n_offset(&bm->ldata, CD_MLOOPUV, n);
-
-        /* needed for indexing loop-tangents */
-        int htype_index = BM_LOOP;
-        if (mesh2tangent->cd_loop_uv_offset == -1) {
-          mesh2tangent->orco = vert_orco;
-          if (!mesh2tangent->orco) {
-            continue;
-          }
-          /* needed for orco lookups */
-          htype_index |= BM_VERT;
-          tangent_mask_curr |= DM_TANGENT_MASK_ORCO;
-        }
-        else {
-          /* Fill the resulting tangent_mask */
-          int uv_ind = CustomData_get_named_layer_index(
-              &bm->ldata, CD_MLOOPUV, loopdata_out->layers[index].name);
-          int uv_start = CustomData_get_layer_index(&bm->ldata, CD_MLOOPUV);
-          BLI_assert(uv_ind != -1 && uv_start != -1);
-          BLI_assert(uv_ind - uv_start < MAX_MTFACE);
-          tangent_mask_curr |= 1 << (uv_ind - uv_start);
-        }
-        if (mesh2tangent->precomputedFaceNormals) {
-          /* needed for face normal lookups */
-          htype_index |= BM_FACE;
-        }
-        BM_mesh_elem_index_ensure(bm, htype_index);
-
-        mesh2tangent->looptris = (const BMLoop *(*)[3])em->looptris;
-        mesh2tangent->tangent = loopdata_out->layers[index].data;
-
-        BLI_task_pool_push(task_pool, emDM_calc_loop_tangents_thread, mesh2tangent, false, NULL);
-      }
-
-      BLI_assert(tangent_mask_curr == tangent_mask);
-      BLI_task_pool_work_and_wait(task_pool);
-      BLI_task_pool_free(task_pool);
-    }
-    else {
-      tangent_mask_curr = tangent_mask;
-    }
-#ifdef USE_LOOPTRI_DETECT_QUADS
-    if (face_as_quad_map) {
-      MEM_freeN(face_as_quad_map);
-    }
-#  undef USE_LOOPTRI_DETECT_QUADS
-#endif
-  }
-
-  *tangent_mask_curr_p = tangent_mask_curr;
-
-  int act_uv_index = CustomData_get_layer_index_n(&bm->ldata, CD_MLOOPUV, act_uv_n);
-  if (act_uv_index >= 0) {
-    int tan_index = CustomData_get_named_layer_index(
-        loopdata_out, CD_TANGENT, bm->ldata.layers[act_uv_index].name);
-    CustomData_set_layer_active_index(loopdata_out, CD_TANGENT, tan_index);
-  } /* else tangent has been built from orco */
-
-  /* Update render layer index */
-  int ren_uv_index = CustomData_get_layer_index_n(&bm->ldata, CD_MLOOPUV, ren_uv_n);
-  if (ren_uv_index >= 0) {
-    int tan_index = CustomData_get_named_layer_index(
-        loopdata_out, CD_TANGENT, bm->ldata.layers[ren_uv_index].name);
-    CustomData_set_layer_render_index(loopdata_out, CD_TANGENT, tan_index);
-  } /* else tangent has been built from orco */
-}
-
-/** \} */
diff --git a/source/blender/blenkernel/intern/editmesh_tangent.cc b/source/blender/blenkernel/intern/editmesh_tangent.cc
new file mode 100644
index 00000000000..a65532d083d
--- /dev/null
+++ b/source/blender/blenkernel/intern/editmesh_tangent.cc
@@ -0,0 +1,331 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/** \file
+ * \ingroup bke
+ */
+
+#include "BLI_math.h"
+#include "BLI_task.h"
+
+#include "DNA_customdata_types.h"
+#include "DNA_defs.h"
+#include "DNA_meshdata_types.h"
+
+#include "BKE_customdata.h"
+#include "BKE_editmesh.h"
+#include "BKE_editmesh_tangent.h"
+#include "BKE_mesh.h"
+#include "BKE_mesh_tangent.h" /* for utility functions */
+
+#include "MEM_guardedalloc.h"
+
+/* interface */
+#include "mikktspace.hh"
+
+/* -------------------------------------------------------------------- */
+/** \name Tangent Space Calculation
+ * \{ */
+
+/* Necessary complexity to handle looptri's as quads for correct tangents */
+#define USE_LOOPTRI_DETECT_QUADS
+
+struct SGLSLEditMeshToTangent {
+  uint GetNumFaces()
+  {
+#ifdef USE_LOOPTRI_DETECT_QUADS
+    return (uint)num_face_as_quad_map;
+#else
+    return (uint)numTessFaces;
+#endif
+  }
+
+  uint GetNumVerticesOfFace(const uint face_num)
+  {
+#ifdef USE_LOOPTRI_DETECT_QUADS
+    if (face_as_quad_map) {
+      if (looptris[face_as_quad_map[face_num]][0]->f->len == 4) {
+        return 4;
+      }
+    }
+    return 3;
+#else
+    UNUSED_VARS(pContext, face_num);
+    return 3;
+#endif
+  }
+
+  const BMLoop *GetLoop(const uint face_num, uint vert_index)
+  {
+    // BLI_assert(vert_index >= 0 && vert_index < 4);
+    const BMLoop **lt;
+    const BMLoop *l;
+
+#ifdef USE_LOOPTRI_DETECT_QUADS
+    if (face_as_quad_map) {
+      lt = looptris[face_as_quad_map[face_num]];
+      if (lt[0]->f->len == 4) {
+        l = BM_FACE_FIRST_LOOP(lt[0]->f);
+        while (vert_index--) {
+          l = l->next;
+        }
+        return l;
+      }
+      /* fall through to regular triangle */
+    }
+    else {
+      lt = looptris[face_num];
+    }
+#else
+    lt = looptris[face_num];
+#endif
+    return lt[vert_index];
+  }
+
+  mikk::float3 GetPosition(const uint face_num, const uint vert_index)
+  {
+    const BMLoop *l = GetLoop(face_num, vert_index);
+    return mikk::float3(l->v->co);
+  }
+
+  mikk::float3 GetTexCoord(const uint face_num, const uint vert_index)
+  {
+    const BMLoop *l = GetLoop(face_num, vert_index);
+    if (cd_loop_uv_offset != -1) {
+      const float *uv = (const float *)BM_ELEM_CD_GET_VOID_P(l, cd_loop_uv_offset);
+      return mikk::float3(uv[0], uv[1], 1.0f);
+    }
+    else {
+      const float *orco_p = orco[BM_elem_index_get(l->v)];
+      float u, v;
+      map_to_sphere(&u, &v, orco_p[0], orco_p[1], orco_p[2]);
+      return mikk::float3(u, v, 1.0f);
+    }
+  }
+
+  mikk::float3 GetNormal(const uint face_num, const uint vert_index)
+  {
+    const BMLoop *l = GetLoop(face_num, vert_index);
+    if (precomputedLoopNormals) {
+      return mikk::float3(precomputedLoopNormals[BM_elem_index_get(l)]);
+    }
+    else if (BM_elem_flag_test(l->f, BM_ELEM_SMOOTH) == 0) { /* flat */
+      if (precomputedFaceNormals) {
+        return mikk::float3(precomputedFaceNormals[BM_elem_index_get(l->f)]);
+      }
+      else {
+        return mikk::float3(l->f->no);
+      }
+    }
+    else {
+      return mikk::float3(l->v->no);
+    }
+  }
+
+  void SetTangentSpace(const uint face_num,
+                       const uint vert_index,
+                       mikk::float3 T,
+                       bool orientation)
+  {
+    const BMLoop *l = GetLoop(face_num, vert_index);
+    float *p_res = tangent[BM_elem_index_get(l)];
+    copy_v4_fl4(p_res, T.x, T.y, T.z, orientation ? 1.0f : -1.0f);
+  }
+
+  const float (*precomputedFaceNormals)[3];
+  const float (*precomputedLoopNormals)[3];
+  const BMLoop *(*looptris)[3];
+  int cd_loop_uv_offset; /* texture coordinates */
+  const float (*orco)[3];
+  float (*tangent)[4]; /* destination */
+  int numTessFaces;
+
+#ifdef USE_LOOPTRI_DETECT_QUADS
+  /* map from 'fake' face index to looptri,
+   * quads will point to the first looptri of the quad */
+  const int *face_as_quad_map;
+  int num_face_as_quad_map;
+#endif
+};
+
+static void emDM_calc_loop_tangents_thread(TaskPool *__restrict UNUSED(pool), void *taskdata)
+{
+  SGLSLEditMeshToTangent *mesh_data = static_cast(taskdata);
+
+  mikk::Mikktspace mikk(*mesh_data);
+  mikk.genTangSpace();
+}
+
+void BKE_editmesh_loop_tangent_calc(BMEditMesh *em,
+                                    bool calc_active_tangent,
+                                    const char (*tangent_names)[MAX_NAME],
+                                    int tangent_names_len,
+                                    const float (*poly_normals)[3],
+                                    const float (*loop_normals)[3],
+                                    const float (*vert_orco)[3],
+                                    /* result */
+                                    CustomData *loopdata_out,
+                                    const uint loopdata_out_len,
+                                    short *tangent_mask_curr_p)
+{
+  BMesh *bm = em->bm;
+
+  int act_uv_n = -1;
+  int ren_uv_n = -1;
+  bool calc_act = false;
+  bool calc_ren = false;
+  char act_uv_name[MAX_NAME];
+  char ren_uv_name[MAX_NAME];
+  short tangent_mask = 0;
+  short tangent_mask_curr = *tangent_mask_curr_p;
+
+  BKE_mesh_calc_loop_tangent_step_0(&bm->ldata,
+                                    calc_active_tangent,
+                                    tangent_names,
+                                    tangent_names_len,
+                                    &calc_act,
+                                    &calc_ren,
+                                    &act_uv_n,
+                                    &ren_uv_n,
+                                    act_uv_name,
+                                    ren_uv_name,
+                                    &tangent_mask);
+
+  if ((tangent_mask_curr | tangent_mask) != tangent_mask_curr) {
+    for (int i = 0; i < tangent_names_len; i++) {
+      if (tangent_names[i][0]) {
+        BKE_mesh_add_loop_tangent_named_layer_for_uv(
+            &bm->ldata, loopdata_out, (int)loopdata_out_len, tangent_names[i]);
+      }
+    }
+    if ((tangent_mask & DM_TANGENT_MASK_ORCO) &&
+        CustomData_get_named_layer_index(loopdata_out, CD_TANGENT, "") == -1) {
+      CustomData_add_layer_named(
+          loopdata_out, CD_TANGENT, CD_SET_DEFAULT, nullptr, (int)loopdata_out_len, "");
+    }
+    if (calc_act && act_uv_name[0]) {
+      BKE_mesh_add_loop_tangent_named_layer_for_uv(
+          &bm->ldata, loopdata_out, (int)loopdata_out_len, act_uv_name);
+    }
+    if (calc_ren && ren_uv_name[0]) {
+      BKE_mesh_add_loop_tangent_named_layer_for_uv(
+          &bm->ldata, loopdata_out, (int)loopdata_out_len, ren_uv_name);
+    }
+    int totface = em->tottri;
+#ifdef USE_LOOPTRI_DETECT_QUADS
+    int num_face_as_quad_map;
+    int *face_as_quad_map = nullptr;
+
+    /* map faces to quads */
+    if (em->tottri != bm->totface) {
+      /* Over allocate, since we don't know how many ngon or quads we have. */
+
+      /* map fake face index to looptri */
+      face_as_quad_map = static_cast(MEM_mallocN(sizeof(int) * totface, __func__));
+      int i, j;
+      for (i = 0, j = 0; j < totface; i++, j++) {
+        face_as_quad_map[i] = j;
+        /* step over all quads */
+        if (em->looptris[j][0]->f->len == 4) {
+          j++; /* skips the nest looptri */
+        }
+      }
+      num_face_as_quad_map = i;
+    }
+    else {
+      num_face_as_quad_map = totface;
+    }
+#endif
+    /* Calculation */
+    if (em->tottri != 0) {
+      TaskPool *task_pool;
+      task_pool = BLI_task_pool_create(nullptr, TASK_PRIORITY_HIGH);
+
+      tangent_mask_curr = 0;
+      /* Calculate tangent layers */
+      SGLSLEditMeshToTangent data_array[MAX_MTFACE];
+      int index = 0;
+      int n = 0;
+      CustomData_update_typemap(loopdata_out);
+      const int tangent_layer_num = CustomData_number_of_layers(loopdata_out, CD_TANGENT);
+      for (n = 0; n < tangent_layer_num; n++) {
+        index = CustomData_get_layer_index_n(loopdata_out, CD_TANGENT, n);
+        BLI_assert(n < MAX_MTFACE);
+        SGLSLEditMeshToTangent *mesh2tangent = &data_array[n];
+        mesh2tangent->numTessFaces = em->tottri;
+#ifdef USE_LOOPTRI_DETECT_QUADS
+        mesh2tangent->face_as_quad_map = face_as_quad_map;
+        mesh2tangent->num_face_as_quad_map = num_face_as_quad_map;
+#endif
+        mesh2tangent->precomputedFaceNormals = poly_normals;
+        /* NOTE: we assume we do have tessellated loop normals at this point
+         * (in case it is object-enabled), have to check this is valid. */
+        mesh2tangent->precomputedLoopNormals = loop_normals;
+        mesh2tangent->cd_loop_uv_offset = CustomData_get_n_offset(&bm->ldata, CD_MLOOPUV, n);
+
+        /* needed for indexing loop-tangents */
+        int htype_index = BM_LOOP;
+        if (mesh2tangent->cd_loop_uv_offset == -1) {
+          mesh2tangent->orco = vert_orco;
+          if (!mesh2tangent->orco) {
+            continue;
+          }
+          /* needed for orco lookups */
+          htype_index |= BM_VERT;
+          tangent_mask_curr |= DM_TANGENT_MASK_ORCO;
+        }
+        else {
+          /* Fill the resulting tangent_mask */
+          int uv_ind = CustomData_get_named_layer_index(
+              &bm->ldata, CD_MLOOPUV, loopdata_out->layers[index].name);
+          int uv_start = CustomData_get_layer_index(&bm->ldata, CD_MLOOPUV);
+          BLI_assert(uv_ind != -1 && uv_start != -1);
+          BLI_assert(uv_ind - uv_start < MAX_MTFACE);
+          tangent_mask_curr |= 1 << (uv_ind - uv_start);
+        }
+        if (mesh2tangent->precomputedFaceNormals) {
+          /* needed for face normal lookups */
+          htype_index |= BM_FACE;
+        }
+        BM_mesh_elem_index_ensure(bm, htype_index);
+
+        mesh2tangent->looptris = (const BMLoop *(*)[3])em->looptris;
+        mesh2tangent->tangent = static_cast(loopdata_out->layers[index].data);
+
+        BLI_task_pool_push(
+            task_pool, emDM_calc_loop_tangents_thread, mesh2tangent, false, nullptr);
+      }
+
+      BLI_assert(tangent_mask_curr == tangent_mask);
+      BLI_task_pool_work_and_wait(task_pool);
+      BLI_task_pool_free(task_pool);
+    }
+    else {
+      tangent_mask_curr = tangent_mask;
+    }
+#ifdef USE_LOOPTRI_DETECT_QUADS
+    if (face_as_quad_map) {
+      MEM_freeN(face_as_quad_map);
+    }
+#  undef USE_LOOPTRI_DETECT_QUADS
+#endif
+  }
+
+  *tangent_mask_curr_p = tangent_mask_curr;
+
+  int act_uv_index = CustomData_get_layer_index_n(&bm->ldata, CD_MLOOPUV, act_uv_n);
+  if (act_uv_index >= 0) {
+    int tan_index = CustomData_get_named_layer_index(
+        loopdata_out, CD_TANGENT, bm->ldata.layers[act_uv_index].name);
+    CustomData_set_layer_active_index(loopdata_out, CD_TANGENT, tan_index);
+  } /* else tangent has been built from orco */
+
+  /* Update render layer index */
+  int ren_uv_index = CustomData_get_layer_index_n(&bm->ldata, CD_MLOOPUV, ren_uv_n);
+  if (ren_uv_index >= 0) {
+    int tan_index = CustomData_get_named_layer_index(
+        loopdata_out, CD_TANGENT, bm->ldata.layers[ren_uv_index].name);
+    CustomData_set_layer_render_index(loopdata_out, CD_TANGENT, tan_index);
+  } /* else tangent has been built from orco */
+}
+
+/** \} */
diff --git a/source/blender/blenkernel/intern/effect.c b/source/blender/blenkernel/intern/effect.c
index 7722c2fa004..6719590e7c0 100644
--- a/source/blender/blenkernel/intern/effect.c
+++ b/source/blender/blenkernel/intern/effect.c
@@ -207,10 +207,11 @@ static void add_effector_evaluation(ListBase **effectors,
 }
 
 ListBase *BKE_effector_relations_create(Depsgraph *depsgraph,
+                                        const Scene *scene,
                                         ViewLayer *view_layer,
                                         Collection *collection)
 {
-  Base *base = BKE_collection_or_layer_objects(view_layer, collection);
+  Base *base = BKE_collection_or_layer_objects(scene, view_layer, collection);
   const bool for_render = (DEG_get_mode(depsgraph) == DAG_EVAL_RENDER);
   const int base_flag = (for_render) ? BASE_ENABLED_RENDER : BASE_ENABLED_VIEWPORT;
 
@@ -700,9 +701,10 @@ bool get_effector_data(EffectorCache *eff,
   else if (eff->pd && eff->pd->shape == PFIELD_SHAPE_POINTS) {
     /* TODO: hair and points object support */
     const Mesh *me_eval = BKE_object_get_evaluated_mesh(eff->ob);
+    const MVert *verts = BKE_mesh_verts(me_eval);
     const float(*vert_normals)[3] = BKE_mesh_vertex_normals_ensure(me_eval);
     if (me_eval != NULL) {
-      copy_v3_v3(efd->loc, me_eval->mvert[*efd->index].co);
+      copy_v3_v3(efd->loc, verts[*efd->index].co);
       copy_v3_v3(efd->nor, vert_normals[*efd->index]);
 
       mul_m4_v3(eff->ob->obmat, efd->loc);
diff --git a/source/blender/blenkernel/intern/fcurve.c b/source/blender/blenkernel/intern/fcurve.c
index 0203620df84..f5876e48241 100644
--- a/source/blender/blenkernel/intern/fcurve.c
+++ b/source/blender/blenkernel/intern/fcurve.c
@@ -37,6 +37,7 @@
 #include "BLO_read_write.h"
 
 #include "RNA_access.h"
+#include "RNA_path.h"
 
 #include "CLG_log.h"
 
@@ -1146,7 +1147,7 @@ void fcurve_samples_to_keyframes(FCurve *fcu, const int start, const int end)
   MEM_SAFE_FREE(fcu->fpt);
 
   /* Not strictly needed since we use linear interpolation, but better be consistent here. */
-  calchandles_fcurve(fcu);
+  BKE_fcurve_handles_recalc(fcu);
 }
 
 /* ***************************** F-Curve Sanity ********************************* */
@@ -1216,7 +1217,7 @@ static BezTriple *cycle_offset_triple(
   return out;
 }
 
-void calchandles_fcurve_ex(FCurve *fcu, eBezTriple_Flag handle_sel_flag)
+void BKE_fcurve_handles_recalc_ex(FCurve *fcu, eBezTriple_Flag handle_sel_flag)
 {
   BezTriple *bezt, *prev, *next;
   int a = fcu->totvert;
@@ -1299,9 +1300,9 @@ void calchandles_fcurve_ex(FCurve *fcu, eBezTriple_Flag handle_sel_flag)
   }
 }
 
-void calchandles_fcurve(FCurve *fcu)
+void BKE_fcurve_handles_recalc(FCurve *fcu)
 {
-  calchandles_fcurve_ex(fcu, SELECT);
+  BKE_fcurve_handles_recalc_ex(fcu, SELECT);
 }
 
 void testhandles_fcurve(FCurve *fcu, eBezTriple_Flag sel_flag, const bool use_handle)
@@ -1320,7 +1321,7 @@ void testhandles_fcurve(FCurve *fcu, eBezTriple_Flag sel_flag, const bool use_ha
   }
 
   /* Recalculate handles. */
-  calchandles_fcurve_ex(fcu, sel_flag);
+  BKE_fcurve_handles_recalc_ex(fcu, sel_flag);
 }
 
 void sort_time_fcurve(FCurve *fcu)
@@ -1590,6 +1591,12 @@ static void berekeny(float f1, float f2, float f3, float f4, float *o, int b)
   }
 }
 
+static void fcurve_bezt_free(FCurve *fcu)
+{
+  MEM_SAFE_FREE(fcu->bezt);
+  fcu->totvert = 0;
+}
+
 bool BKE_fcurve_bezt_subdivide_handles(struct BezTriple *bezt,
                                        struct BezTriple *prev,
                                        struct BezTriple *next,
@@ -1651,6 +1658,69 @@ bool BKE_fcurve_bezt_subdivide_handles(struct BezTriple *bezt,
   return true;
 }
 
+void BKE_fcurve_delete_key(FCurve *fcu, int index)
+{
+  /* sanity check */
+  if (fcu == NULL) {
+    return;
+  }
+
+  /* verify the index:
+   * 1) cannot be greater than the number of available keyframes
+   * 2) negative indices are for specifying a value from the end of the array
+   */
+  if (abs(index) >= fcu->totvert) {
+    return;
+  }
+  if (index < 0) {
+    index += fcu->totvert;
+  }
+
+  /* Delete this keyframe */
+  memmove(
+      &fcu->bezt[index], &fcu->bezt[index + 1], sizeof(BezTriple) * (fcu->totvert - index - 1));
+  fcu->totvert--;
+
+  /* Free the array of BezTriples if there are not keyframes */
+  if (fcu->totvert == 0) {
+    fcurve_bezt_free(fcu);
+  }
+}
+
+bool BKE_fcurve_delete_keys_selected(FCurve *fcu)
+{
+  bool changed = false;
+
+  if (fcu->bezt == NULL) { /* ignore baked curves */
+    return false;
+  }
+
+  /* Delete selected BezTriples */
+  for (int i = 0; i < fcu->totvert; i++) {
+    if (fcu->bezt[i].f2 & SELECT) {
+      if (i == fcu->active_keyframe_index) {
+        BKE_fcurve_active_keyframe_set(fcu, NULL);
+      }
+      memmove(&fcu->bezt[i], &fcu->bezt[i + 1], sizeof(BezTriple) * (fcu->totvert - i - 1));
+      fcu->totvert--;
+      i--;
+      changed = true;
+    }
+  }
+
+  /* Free the array of BezTriples if there are not keyframes */
+  if (fcu->totvert == 0) {
+    fcurve_bezt_free(fcu);
+  }
+
+  return changed;
+}
+
+void BKE_fcurve_delete_keys_all(FCurve *fcu)
+{
+  fcurve_bezt_free(fcu);
+}
+
 /** \} */
 
 /* -------------------------------------------------------------------- */
diff --git a/source/blender/blenkernel/intern/fcurve_driver.c b/source/blender/blenkernel/intern/fcurve_driver.c
index 5d54c5c039b..aa33bef998f 100644
--- a/source/blender/blenkernel/intern/fcurve_driver.c
+++ b/source/blender/blenkernel/intern/fcurve_driver.c
@@ -30,6 +30,7 @@
 #include "BKE_object.h"
 
 #include "RNA_access.h"
+#include "RNA_path.h"
 
 #include "atomic_ops.h"
 
diff --git a/source/blender/blenkernel/intern/fcurve_test.cc b/source/blender/blenkernel/intern/fcurve_test.cc
index 1912e3a9d8d..285c6a0af4d 100644
--- a/source/blender/blenkernel/intern/fcurve_test.cc
+++ b/source/blender/blenkernel/intern/fcurve_test.cc
@@ -7,7 +7,6 @@
 #include "BKE_fcurve.h"
 
 #include "ED_keyframing.h"
-#include "ED_types.h" /* For SELECT. */
 
 #include "DNA_anim_types.h"
 
diff --git a/source/blender/blenkernel/intern/fluid.c b/source/blender/blenkernel/intern/fluid.c
index 8e95bf18c6b..349614b93dd 100644
--- a/source/blender/blenkernel/intern/fluid.c
+++ b/source/blender/blenkernel/intern/fluid.c
@@ -27,6 +27,7 @@
 #include "BKE_effect.h"
 #include "BKE_fluid.h"
 #include "BKE_global.h"
+#include "BKE_layer.h"
 #include "BKE_lib_id.h"
 #include "BKE_modifier.h"
 #include "BKE_pointcache.h"
@@ -79,7 +80,7 @@
 /** Max value for phi initialization */
 #define PHI_MAX 9999.0f
 
-static void BKE_fluid_modifier_reset_ex(struct FluidModifierData *fmd, bool need_lock);
+static void fluid_modifier_reset_ex(struct FluidModifierData *fmd, bool need_lock);
 
 #ifdef WITH_FLUID
 // #define DEBUG_PRINT
@@ -403,7 +404,8 @@ static void manta_set_domain_from_mesh(FluidDomainSettings *fds,
   size_t i;
   float min[3] = {FLT_MAX, FLT_MAX, FLT_MAX}, max[3] = {-FLT_MAX, -FLT_MAX, -FLT_MAX};
   float size[3];
-  MVert *verts = me->mvert;
+
+  MVert *verts = BKE_mesh_verts_for_write(me);
   float scale = 0.0;
   int res;
 
@@ -480,7 +482,7 @@ static void update_final_gravity(FluidDomainSettings *fds, Scene *scene)
   mul_v3_fl(fds->gravity_final, fds->effector_weights->global_gravity);
 }
 
-static bool BKE_fluid_modifier_init(
+static bool fluid_modifier_init(
     FluidModifierData *fmd, Depsgraph *depsgraph, Object *ob, Scene *scene, Mesh *me)
 {
   int scene_framenr = (int)DEG_get_ctime(depsgraph);
@@ -542,7 +544,9 @@ static bool BKE_fluid_modifier_init(
 }
 
 /* Forward declarations. */
-static void manta_smoke_calc_transparency(FluidDomainSettings *fds, ViewLayer *view_layer);
+static void manta_smoke_calc_transparency(FluidDomainSettings *fds,
+                                          Scene *scene,
+                                          ViewLayer *view_layer);
 static float calc_voxel_transp(
     float *result, const float *input, int res[3], int *pixel, float *t_ray, float correct);
 static void update_distances(int index,
@@ -552,13 +556,13 @@ static void update_distances(int index,
                              float surface_thickness,
                              bool use_plane_init);
 
-static int get_light(ViewLayer *view_layer, float *light)
+static int get_light(Scene *scene, ViewLayer *view_layer, float *light)
 {
-  Base *base_tmp = NULL;
   int found_light = 0;
 
   /* Try to find a lamp, preferably local. */
-  for (base_tmp = FIRSTBASE(view_layer); base_tmp; base_tmp = base_tmp->next) {
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  LISTBASE_FOREACH (Base *, base_tmp, BKE_view_layer_object_bases_get(view_layer)) {
     if (base_tmp->object->type == OB_LAMP) {
       Light *la = base_tmp->object->data;
 
@@ -994,28 +998,19 @@ static void obstacles_from_mesh(Object *coll_ob,
                                 float dt)
 {
   if (fes->mesh) {
-    Mesh *me = NULL;
-    MVert *mvert = NULL;
     const MLoopTri *looptri;
-    const MLoop *mloop;
     BVHTreeFromMesh tree_data = {NULL};
     int numverts, i;
 
     float *vert_vel = NULL;
     bool has_velocity = false;
 
-    me = BKE_mesh_copy_for_eval(fes->mesh, true);
+    Mesh *me = BKE_mesh_copy_for_eval(fes->mesh, false);
+    MVert *verts = BKE_mesh_verts_for_write(me);
 
     int min[3], max[3], res[3];
 
-    /* Duplicate vertices to modify. */
-    if (me->mvert) {
-      me->mvert = MEM_dupallocN(me->mvert);
-      CustomData_set_layer(&me->vdata, CD_MVERT, me->mvert);
-    }
-
-    mvert = me->mvert;
-    mloop = me->mloop;
+    const MLoop *mloop = BKE_mesh_loops(me);
     looptri = BKE_mesh_runtime_looptri_ensure(me);
     numverts = me->totvert;
 
@@ -1038,22 +1033,15 @@ static void obstacles_from_mesh(Object *coll_ob,
 
     /* Transform mesh vertices to domain grid space for fast lookups.
      * This is valid because the mesh is copied above. */
-    BKE_mesh_vertex_normals_ensure(me);
-    float(*vert_normals)[3] = BKE_mesh_vertex_normals_for_write(me);
     for (i = 0; i < numverts; i++) {
       float co[3];
 
       /* Vertex position. */
-      mul_m4_v3(coll_ob->obmat, mvert[i].co);
-      manta_pos_to_cell(fds, mvert[i].co);
-
-      /* Vertex normal. */
-      mul_mat3_m4_v3(coll_ob->obmat, vert_normals[i]);
-      mul_mat3_m4_v3(fds->imat, vert_normals[i]);
-      normalize_v3(vert_normals[i]);
+      mul_m4_v3(coll_ob->obmat, verts[i].co);
+      manta_pos_to_cell(fds, verts[i].co);
 
       /* Vertex velocity. */
-      add_v3fl_v3fl_v3i(co, mvert[i].co, fds->shift);
+      add_v3fl_v3fl_v3i(co, verts[i].co, fds->shift);
       if (has_velocity) {
         sub_v3_v3v3(&vert_vel[i * 3], co, &fes->verts_old[i * 3]);
         mul_v3_fl(&vert_vel[i * 3], 1.0f / dt);
@@ -1061,7 +1049,7 @@ static void obstacles_from_mesh(Object *coll_ob,
       copy_v3_v3(&fes->verts_old[i * 3], co);
 
       /* Calculate emission map bounds. */
-      bb_boundInsert(bb, mvert[i].co);
+      bb_boundInsert(bb, verts[i].co);
     }
 
     /* Set emission map.
@@ -1083,7 +1071,7 @@ static void obstacles_from_mesh(Object *coll_ob,
 
       ObstaclesFromDMData data = {
           .fes = fes,
-          .mvert = mvert,
+          .mvert = verts,
           .mloop = mloop,
           .mlooptri = looptri,
           .tree = &tree_data,
@@ -1106,9 +1094,6 @@ static void obstacles_from_mesh(Object *coll_ob,
     if (vert_vel) {
       MEM_freeN(vert_vel);
     }
-    if (me->mvert) {
-      MEM_freeN(me->mvert);
-    }
     BKE_id_free(NULL, me);
   }
 }
@@ -2085,19 +2070,13 @@ static void emit_from_mesh(
 
     /* Copy mesh for thread safety as we modify it.
      * Main issue is its VertArray being modified, then replaced and freed. */
-    Mesh *me = BKE_mesh_copy_for_eval(ffs->mesh, true);
+    Mesh *me = BKE_mesh_copy_for_eval(ffs->mesh, false);
+    MVert *verts = BKE_mesh_verts_for_write(me);
 
-    /* Duplicate vertices to modify. */
-    if (me->mvert) {
-      me->mvert = MEM_dupallocN(me->mvert);
-      CustomData_set_layer(&me->vdata, CD_MVERT, me->mvert);
-    }
-
-    MVert *mvert = me->mvert;
-    const MLoop *mloop = me->mloop;
+    const MLoop *mloop = BKE_mesh_loops(me);
     const MLoopTri *mlooptri = BKE_mesh_runtime_looptri_ensure(me);
     const int numverts = me->totvert;
-    const MDeformVert *dvert = CustomData_get_layer(&me->vdata, CD_MDEFORMVERT);
+    const MDeformVert *dvert = BKE_mesh_deform_verts(me);
     const MLoopUV *mloopuv = CustomData_get_layer_named(&me->ldata, CD_MLOOPUV, ffs->uvlayer_name);
 
     if (ffs->flags & FLUID_FLOW_INITVELOCITY) {
@@ -2121,8 +2100,8 @@ static void emit_from_mesh(
     float(*vert_normals)[3] = BKE_mesh_vertex_normals_for_write(me);
     for (i = 0; i < numverts; i++) {
       /* Vertex position. */
-      mul_m4_v3(flow_ob->obmat, mvert[i].co);
-      manta_pos_to_cell(fds, mvert[i].co);
+      mul_m4_v3(flow_ob->obmat, verts[i].co);
+      manta_pos_to_cell(fds, verts[i].co);
 
       /* Vertex normal. */
       mul_mat3_m4_v3(flow_ob->obmat, vert_normals[i]);
@@ -2132,7 +2111,7 @@ static void emit_from_mesh(
       /* Vertex velocity. */
       if (ffs->flags & FLUID_FLOW_INITVELOCITY) {
         float co[3];
-        add_v3fl_v3fl_v3i(co, mvert[i].co, fds->shift);
+        add_v3fl_v3fl_v3i(co, verts[i].co, fds->shift);
         if (has_velocity) {
           sub_v3_v3v3(&vert_vel[i * 3], co, &ffs->verts_old[i * 3]);
           mul_v3_fl(&vert_vel[i * 3], 1.0 / dt);
@@ -2141,7 +2120,7 @@ static void emit_from_mesh(
       }
 
       /* Calculate emission map bounds. */
-      bb_boundInsert(bb, mvert[i].co);
+      bb_boundInsert(bb, verts[i].co);
     }
     mul_m4_v3(flow_ob->obmat, flow_center);
     manta_pos_to_cell(fds, flow_center);
@@ -2166,7 +2145,7 @@ static void emit_from_mesh(
       EmitFromDMData data = {
           .fds = fds,
           .ffs = ffs,
-          .mvert = mvert,
+          .mvert = verts,
           .vert_normals = vert_normals,
           .mloop = mloop,
           .mlooptri = mlooptri,
@@ -2194,9 +2173,6 @@ static void emit_from_mesh(
     if (vert_vel) {
       MEM_freeN(vert_vel);
     }
-    if (me->mvert) {
-      MEM_freeN(me->mvert);
-    }
     BKE_id_free(NULL, me);
   }
 }
@@ -3249,12 +3225,13 @@ static Mesh *create_liquid_geometry(FluidDomainSettings *fds,
    * If there are no faces in original mesh, keep materials and flags unchanged. */
   MPoly *mpoly;
   MPoly mp_example = {0};
-  mpoly = orgmesh->mpoly;
+  mpoly = BKE_mesh_polys_for_write(orgmesh);
   if (mpoly) {
     mp_example = *mpoly;
   }
 
-  const short mp_mat_nr = mp_example.mat_nr;
+  const int *orig_material_indices = BKE_mesh_material_indices(orgmesh);
+  const short mp_mat_nr = orig_material_indices ? orig_material_indices[0] : 0;
   const char mp_flag = mp_example.flag;
 
   int i;
@@ -3280,9 +3257,9 @@ static Mesh *create_liquid_geometry(FluidDomainSettings *fds,
   if (!me) {
     return NULL;
   }
-  mverts = me->mvert;
-  mpolys = me->mpoly;
-  mloops = me->mloop;
+  mverts = BKE_mesh_verts_for_write(me);
+  mpolys = BKE_mesh_polys_for_write(me);
+  mloops = BKE_mesh_loops_for_write(me);
 
   /* Get size (dimension) but considering scaling. */
   copy_v3_v3(cell_size_scaled, fds->cell_size);
@@ -3365,10 +3342,12 @@ static Mesh *create_liquid_geometry(FluidDomainSettings *fds,
     }
   }
 
+  int *material_indices = BKE_mesh_material_indices_for_write(me);
+
   /* Loop for triangles. */
   for (i = 0; i < num_faces; i++, mpolys++, mloops += 3) {
     /* Initialize from existing face. */
-    mpolys->mat_nr = mp_mat_nr;
+    material_indices[i] = mp_mat_nr;
     mpolys->flag = mp_flag;
 
     mpolys->loopstart = i * 3;
@@ -3414,9 +3393,9 @@ static Mesh *create_smoke_geometry(FluidDomainSettings *fds, Mesh *orgmesh, Obje
   }
 
   result = BKE_mesh_new_nomain(num_verts, 0, 0, num_faces * 4, num_faces);
-  mverts = result->mvert;
-  mpolys = result->mpoly;
-  mloops = result->mloop;
+  mverts = BKE_mesh_verts_for_write(result);
+  mpolys = BKE_mesh_polys_for_write(result);
+  mloops = BKE_mesh_loops_for_write(result);
 
   if (num_verts) {
     /* Volume bounds. */
@@ -3614,7 +3593,8 @@ static int manta_step(
 
   /* Compute shadow grid for gas simulations. Make sure to skip if bake job was canceled early. */
   if (fds->type == FLUID_DOMAIN_TYPE_GAS && result) {
-    manta_smoke_calc_transparency(fds, DEG_get_evaluated_view_layer(depsgraph));
+    manta_smoke_calc_transparency(
+        fds, DEG_get_evaluated_scene(depsgraph), DEG_get_evaluated_view_layer(depsgraph));
   }
 
   BLI_mutex_unlock(&object_update_lock);
@@ -3635,15 +3615,15 @@ static void manta_guiding(
   BLI_mutex_unlock(&object_update_lock);
 }
 
-static void BKE_fluid_modifier_processFlow(FluidModifierData *fmd,
-                                           Depsgraph *depsgraph,
-                                           Scene *scene,
-                                           Object *ob,
-                                           Mesh *me,
-                                           const int scene_framenr)
+static void fluid_modifier_processFlow(FluidModifierData *fmd,
+                                       Depsgraph *depsgraph,
+                                       Scene *scene,
+                                       Object *ob,
+                                       Mesh *me,
+                                       const int scene_framenr)
 {
   if (scene_framenr >= fmd->time) {
-    BKE_fluid_modifier_init(fmd, depsgraph, ob, scene, me);
+    fluid_modifier_init(fmd, depsgraph, ob, scene, me);
   }
 
   if (fmd->flow) {
@@ -3658,19 +3638,19 @@ static void BKE_fluid_modifier_processFlow(FluidModifierData *fmd,
   }
   else if (scene_framenr < fmd->time) {
     fmd->time = scene_framenr;
-    BKE_fluid_modifier_reset_ex(fmd, false);
+    fluid_modifier_reset_ex(fmd, false);
   }
 }
 
-static void BKE_fluid_modifier_processEffector(FluidModifierData *fmd,
-                                               Depsgraph *depsgraph,
-                                               Scene *scene,
-                                               Object *ob,
-                                               Mesh *me,
-                                               const int scene_framenr)
+static void fluid_modifier_processEffector(FluidModifierData *fmd,
+                                           Depsgraph *depsgraph,
+                                           Scene *scene,
+                                           Object *ob,
+                                           Mesh *me,
+                                           const int scene_framenr)
 {
   if (scene_framenr >= fmd->time) {
-    BKE_fluid_modifier_init(fmd, depsgraph, ob, scene, me);
+    fluid_modifier_init(fmd, depsgraph, ob, scene, me);
   }
 
   if (fmd->effector) {
@@ -3685,16 +3665,16 @@ static void BKE_fluid_modifier_processEffector(FluidModifierData *fmd,
   }
   else if (scene_framenr < fmd->time) {
     fmd->time = scene_framenr;
-    BKE_fluid_modifier_reset_ex(fmd, false);
+    fluid_modifier_reset_ex(fmd, false);
   }
 }
 
-static void BKE_fluid_modifier_processDomain(FluidModifierData *fmd,
-                                             Depsgraph *depsgraph,
-                                             Scene *scene,
-                                             Object *ob,
-                                             Mesh *me,
-                                             const int scene_framenr)
+static void fluid_modifier_processDomain(FluidModifierData *fmd,
+                                         Depsgraph *depsgraph,
+                                         Scene *scene,
+                                         Object *ob,
+                                         Mesh *me,
+                                         const int scene_framenr)
 {
   FluidDomainSettings *fds = fmd->domain;
   Object *guide_parent = NULL;
@@ -3740,7 +3720,7 @@ static void BKE_fluid_modifier_processDomain(FluidModifierData *fmd,
 
   /* Reset fluid if no fluid present. Also resets active fields. */
   if (!fds->fluid) {
-    BKE_fluid_modifier_reset_ex(fmd, false);
+    fluid_modifier_reset_ex(fmd, false);
   }
 
   /* Ensure cache directory is not relative. */
@@ -3768,12 +3748,12 @@ static void BKE_fluid_modifier_processDomain(FluidModifierData *fmd,
     if (pid.cache->flag & PTCACHE_OUTDATED) {
       BKE_ptcache_id_reset(scene, &pid, PTCACHE_RESET_OUTDATED);
       BKE_fluid_cache_free_all(fds, ob);
-      BKE_fluid_modifier_reset_ex(fmd, false);
+      fluid_modifier_reset_ex(fmd, false);
     }
   }
 
   /* Fluid domain init must not fail in order to continue modifier evaluation. */
-  if (!fds->fluid && !BKE_fluid_modifier_init(fmd, depsgraph, ob, scene, me)) {
+  if (!fds->fluid && !fluid_modifier_init(fmd, depsgraph, ob, scene, me)) {
     CLOG_ERROR(&LOG, "Fluid initialization failed. Should not happen!");
     return;
   }
@@ -4101,19 +4081,19 @@ static void BKE_fluid_modifier_processDomain(FluidModifierData *fmd,
   fmd->time = scene_framenr;
 }
 
-static void BKE_fluid_modifier_process(
+static void fluid_modifier_process(
     FluidModifierData *fmd, Depsgraph *depsgraph, Scene *scene, Object *ob, Mesh *me)
 {
   const int scene_framenr = (int)DEG_get_ctime(depsgraph);
 
   if (fmd->type & MOD_FLUID_TYPE_FLOW) {
-    BKE_fluid_modifier_processFlow(fmd, depsgraph, scene, ob, me, scene_framenr);
+    fluid_modifier_processFlow(fmd, depsgraph, scene, ob, me, scene_framenr);
   }
   else if (fmd->type & MOD_FLUID_TYPE_EFFEC) {
-    BKE_fluid_modifier_processEffector(fmd, depsgraph, scene, ob, me, scene_framenr);
+    fluid_modifier_processEffector(fmd, depsgraph, scene, ob, me, scene_framenr);
   }
   else if (fmd->type & MOD_FLUID_TYPE_DOMAIN) {
-    BKE_fluid_modifier_processDomain(fmd, depsgraph, scene, ob, me, scene_framenr);
+    fluid_modifier_processDomain(fmd, depsgraph, scene, ob, me, scene_framenr);
   }
 }
 
@@ -4131,7 +4111,7 @@ struct Mesh *BKE_fluid_modifier_do(
       BLI_rw_mutex_lock(fmd->domain->fluid_mutex, THREAD_LOCK_WRITE);
     }
 
-    BKE_fluid_modifier_process(fmd, depsgraph, scene, ob, me);
+    fluid_modifier_process(fmd, depsgraph, scene, ob, me);
 
     if ((fmd->type & MOD_FLUID_TYPE_DOMAIN) && fmd->domain) {
       BLI_rw_mutex_unlock(fmd->domain->fluid_mutex);
@@ -4313,7 +4293,9 @@ static void bresenham_linie_3D(int x1,
   cb(result, input, res, pixel, t_ray, correct);
 }
 
-static void manta_smoke_calc_transparency(FluidDomainSettings *fds, ViewLayer *view_layer)
+static void manta_smoke_calc_transparency(FluidDomainSettings *fds,
+                                          Scene *scene,
+                                          ViewLayer *view_layer)
 {
   float bv[6] = {0};
   float light[3];
@@ -4322,7 +4304,7 @@ static void manta_smoke_calc_transparency(FluidDomainSettings *fds, ViewLayer *v
   float *shadow = manta_smoke_get_shadow(fds->fluid);
   float correct = -7.0f * fds->dx;
 
-  if (!get_light(view_layer, light)) {
+  if (!get_light(scene, view_layer, light)) {
     return;
   }
 
@@ -4704,7 +4686,7 @@ void BKE_fluid_fields_sanitize(FluidDomainSettings *settings)
  * Use for versioning, even when fluids are disabled.
  * \{ */
 
-static void BKE_fluid_modifier_freeDomain(FluidModifierData *fmd)
+static void fluid_modifier_freeDomain(FluidModifierData *fmd)
 {
   if (fmd->domain) {
     if (fmd->domain->fluid) {
@@ -4733,7 +4715,7 @@ static void BKE_fluid_modifier_freeDomain(FluidModifierData *fmd)
   }
 }
 
-static void BKE_fluid_modifier_freeFlow(FluidModifierData *fmd)
+static void fluid_modifier_freeFlow(FluidModifierData *fmd)
 {
   if (fmd->flow) {
     if (fmd->flow->mesh) {
@@ -4750,7 +4732,7 @@ static void BKE_fluid_modifier_freeFlow(FluidModifierData *fmd)
   }
 }
 
-static void BKE_fluid_modifier_freeEffector(FluidModifierData *fmd)
+static void fluid_modifier_freeEffector(FluidModifierData *fmd)
 {
   if (fmd->effector) {
     if (fmd->effector->mesh) {
@@ -4767,7 +4749,7 @@ static void BKE_fluid_modifier_freeEffector(FluidModifierData *fmd)
   }
 }
 
-static void BKE_fluid_modifier_reset_ex(struct FluidModifierData *fmd, bool need_lock)
+static void fluid_modifier_reset_ex(struct FluidModifierData *fmd, bool need_lock)
 {
   if (!fmd) {
     return;
@@ -4807,7 +4789,7 @@ static void BKE_fluid_modifier_reset_ex(struct FluidModifierData *fmd, bool need
 
 void BKE_fluid_modifier_reset(struct FluidModifierData *fmd)
 {
-  BKE_fluid_modifier_reset_ex(fmd, true);
+  fluid_modifier_reset_ex(fmd, true);
 }
 
 void BKE_fluid_modifier_free(FluidModifierData *fmd)
@@ -4816,9 +4798,9 @@ void BKE_fluid_modifier_free(FluidModifierData *fmd)
     return;
   }
 
-  BKE_fluid_modifier_freeDomain(fmd);
-  BKE_fluid_modifier_freeFlow(fmd);
-  BKE_fluid_modifier_freeEffector(fmd);
+  fluid_modifier_freeDomain(fmd);
+  fluid_modifier_freeFlow(fmd);
+  fluid_modifier_freeEffector(fmd);
 }
 
 void BKE_fluid_modifier_create_type_data(struct FluidModifierData *fmd)
@@ -4829,7 +4811,7 @@ void BKE_fluid_modifier_create_type_data(struct FluidModifierData *fmd)
 
   if (fmd->type & MOD_FLUID_TYPE_DOMAIN) {
     if (fmd->domain) {
-      BKE_fluid_modifier_freeDomain(fmd);
+      fluid_modifier_freeDomain(fmd);
     }
 
     fmd->domain = DNA_struct_default_alloc(FluidDomainSettings);
@@ -4861,7 +4843,7 @@ void BKE_fluid_modifier_create_type_data(struct FluidModifierData *fmd)
   }
   else if (fmd->type & MOD_FLUID_TYPE_FLOW) {
     if (fmd->flow) {
-      BKE_fluid_modifier_freeFlow(fmd);
+      fluid_modifier_freeFlow(fmd);
     }
 
     fmd->flow = DNA_struct_default_alloc(FluidFlowSettings);
@@ -4869,7 +4851,7 @@ void BKE_fluid_modifier_create_type_data(struct FluidModifierData *fmd)
   }
   else if (fmd->type & MOD_FLUID_TYPE_EFFEC) {
     if (fmd->effector) {
-      BKE_fluid_modifier_freeEffector(fmd);
+      fluid_modifier_freeEffector(fmd);
     }
 
     fmd->effector = DNA_struct_default_alloc(FluidEffectorSettings);
diff --git a/source/blender/blenkernel/intern/fmodifier.c b/source/blender/blenkernel/intern/fmodifier.c
index 1bb7c49d616..11c3dfc18dc 100644
--- a/source/blender/blenkernel/intern/fmodifier.c
+++ b/source/blender/blenkernel/intern/fmodifier.c
@@ -768,19 +768,19 @@ static void fcm_cycles_evaluate(FCurve *UNUSED(fcu),
 }
 
 static FModifierTypeInfo FMI_CYCLES = {
-    FMODIFIER_TYPE_CYCLES,      /* type */
-    sizeof(FMod_Cycles),        /* size */
-    FMI_TYPE_EXTRAPOLATION,     /* action type */
-    FMI_REQUIRES_ORIGINAL_DATA, /* requirements */
-    N_("Cycles"),               /* name */
-    "FMod_Cycles",              /* struct name */
-    sizeof(tFCMED_Cycles),      /* storage size */
-    NULL,                       /* free data */
-    NULL,                       /* copy data */
-    fcm_cycles_new_data,        /* new data */
-    NULL /*fcm_cycles_verify*/, /* verify */
-    fcm_cycles_time,            /* evaluate time */
-    fcm_cycles_evaluate,        /* evaluate */
+    FMODIFIER_TYPE_CYCLES,                       /* type */
+    sizeof(FMod_Cycles),                         /* size */
+    FMI_TYPE_EXTRAPOLATION,                      /* action type */
+    FMI_REQUIRES_ORIGINAL_DATA,                  /* requirements */
+    CTX_N_(BLT_I18NCONTEXT_ID_ACTION, "Cycles"), /* name */
+    "FMod_Cycles",                               /* struct name */
+    sizeof(tFCMED_Cycles),                       /* storage size */
+    NULL,                                        /* free data */
+    NULL,                                        /* copy data */
+    fcm_cycles_new_data,                         /* new data */
+    NULL /*fcm_cycles_verify*/,                  /* verify */
+    fcm_cycles_time,                             /* evaluate time */
+    fcm_cycles_evaluate,                         /* evaluate */
 };
 
 /* Noise F-Curve Modifier  --------------------------- */
@@ -1127,7 +1127,7 @@ FModifier *add_fmodifier(ListBase *modifiers, int type, FCurve *owner_fcu)
 
   /* update the fcurve if the Cycles modifier is added */
   if ((owner_fcu) && (type == FMODIFIER_TYPE_CYCLES)) {
-    calchandles_fcurve(owner_fcu);
+    BKE_fcurve_handles_recalc(owner_fcu);
   }
 
   /* return modifier for further editing */
@@ -1215,7 +1215,7 @@ bool remove_fmodifier(ListBase *modifiers, FModifier *fcm)
 
     /* update the fcurve if the Cycles modifier is removed */
     if (update_fcu) {
-      calchandles_fcurve(update_fcu);
+      BKE_fcurve_handles_recalc(update_fcu);
     }
 
     return true;
diff --git a/source/blender/blenkernel/intern/geometry_component_curve.cc b/source/blender/blenkernel/intern/geometry_component_curve.cc
deleted file mode 100644
index 0d899ec7b06..00000000000
--- a/source/blender/blenkernel/intern/geometry_component_curve.cc
+++ /dev/null
@@ -1,1463 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-
-#include "BLI_task.hh"
-
-#include "DNA_ID_enums.h"
-#include "DNA_curve_types.h"
-
-#include "BKE_attribute_math.hh"
-#include "BKE_curve.h"
-#include "BKE_geometry_set.hh"
-#include "BKE_lib_id.h"
-#include "BKE_spline.hh"
-
-#include "attribute_access_intern.hh"
-
-using blender::GMutableSpan;
-using blender::GSpan;
-using blender::GVArray;
-using blender::GVArraySpan;
-
-/* -------------------------------------------------------------------- */
-/** \name Geometry Component Implementation
- * \{ */
-
-CurveComponentLegacy::CurveComponentLegacy() : GeometryComponent(GEO_COMPONENT_TYPE_CURVE)
-{
-}
-
-CurveComponentLegacy::~CurveComponentLegacy()
-{
-  this->clear();
-}
-
-GeometryComponent *CurveComponentLegacy::copy() const
-{
-  CurveComponentLegacy *new_component = new CurveComponentLegacy();
-  if (curve_ != nullptr) {
-    new_component->curve_ = new CurveEval(*curve_);
-    new_component->ownership_ = GeometryOwnershipType::Owned;
-  }
-  return new_component;
-}
-
-void CurveComponentLegacy::clear()
-{
-  BLI_assert(this->is_mutable());
-  if (curve_ != nullptr) {
-    if (ownership_ == GeometryOwnershipType::Owned) {
-      delete curve_;
-    }
-    curve_ = nullptr;
-  }
-}
-
-bool CurveComponentLegacy::has_curve() const
-{
-  return curve_ != nullptr;
-}
-
-void CurveComponentLegacy::replace(CurveEval *curve, GeometryOwnershipType ownership)
-{
-  BLI_assert(this->is_mutable());
-  this->clear();
-  curve_ = curve;
-  ownership_ = ownership;
-}
-
-CurveEval *CurveComponentLegacy::release()
-{
-  BLI_assert(this->is_mutable());
-  CurveEval *curve = curve_;
-  curve_ = nullptr;
-  return curve;
-}
-
-const CurveEval *CurveComponentLegacy::get_for_read() const
-{
-  return curve_;
-}
-
-CurveEval *CurveComponentLegacy::get_for_write()
-{
-  BLI_assert(this->is_mutable());
-  if (ownership_ == GeometryOwnershipType::ReadOnly) {
-    curve_ = new CurveEval(*curve_);
-    ownership_ = GeometryOwnershipType::Owned;
-  }
-  return curve_;
-}
-
-bool CurveComponentLegacy::is_empty() const
-{
-  return curve_ == nullptr;
-}
-
-bool CurveComponentLegacy::owns_direct_data() const
-{
-  return ownership_ == GeometryOwnershipType::Owned;
-}
-
-void CurveComponentLegacy::ensure_owns_direct_data()
-{
-  BLI_assert(this->is_mutable());
-  if (ownership_ != GeometryOwnershipType::Owned) {
-    curve_ = new CurveEval(*curve_);
-    ownership_ = GeometryOwnershipType::Owned;
-  }
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Attribute Access Helper Functions
- * \{ */
-
-namespace blender::bke {
-
-namespace {
-struct PointIndices {
-  int spline_index;
-  int point_index;
-};
-}  // namespace
-static PointIndices lookup_point_indices(Span offsets, const int index)
-{
-  const int spline_index = std::upper_bound(offsets.begin(), offsets.end(), index) -
-                           offsets.begin() - 1;
-  const int index_in_spline = index - offsets[spline_index];
-  return {spline_index, index_in_spline};
-}
-
-/**
- * Mix together all of a spline's control point values.
- *
- * \note Theoretically this interpolation does not need to compute all values at once.
- * However, doing that makes the implementation simpler, and this can be optimized in the future if
- * only some values are required.
- */
-template
-static void adapt_curve_domain_point_to_spline_impl(const CurveEval &curve,
-                                                    const VArray &old_values,
-                                                    MutableSpan r_values)
-{
-  const int splines_len = curve.splines().size();
-  Array offsets = curve.control_point_offsets();
-  BLI_assert(r_values.size() == splines_len);
-  attribute_math::DefaultMixer mixer(r_values);
-
-  for (const int i_spline : IndexRange(splines_len)) {
-    const int spline_offset = offsets[i_spline];
-    const int spline_point_len = offsets[i_spline + 1] - spline_offset;
-    for (const int i_point : IndexRange(spline_point_len)) {
-      const T value = old_values[spline_offset + i_point];
-      mixer.mix_in(i_spline, value);
-    }
-  }
-
-  mixer.finalize();
-}
-
-/**
- * A spline is selected if all of its control points were selected.
- *
- * \note Theoretically this interpolation does not need to compute all values at once.
- * However, doing that makes the implementation simpler, and this can be optimized in the future if
- * only some values are required.
- */
-template<>
-void adapt_curve_domain_point_to_spline_impl(const CurveEval &curve,
-                                             const VArray &old_values,
-                                             MutableSpan r_values)
-{
-  const int splines_len = curve.splines().size();
-  Array offsets = curve.control_point_offsets();
-  BLI_assert(r_values.size() == splines_len);
-
-  r_values.fill(true);
-
-  for (const int i_spline : IndexRange(splines_len)) {
-    const int spline_offset = offsets[i_spline];
-    const int spline_point_len = offsets[i_spline + 1] - spline_offset;
-
-    for (const int i_point : IndexRange(spline_point_len)) {
-      if (!old_values[spline_offset + i_point]) {
-        r_values[i_spline] = false;
-        break;
-      }
-    }
-  }
-}
-
-static GVArray adapt_curve_domain_point_to_spline(const CurveEval &curve, GVArray varray)
-{
-  GVArray new_varray;
-  attribute_math::convert_to_static_type(varray.type(), [&](auto dummy) {
-    using T = decltype(dummy);
-    if constexpr (!std::is_void_v>) {
-      Array values(curve.splines().size());
-      adapt_curve_domain_point_to_spline_impl(curve, varray.typed(), values);
-      new_varray = VArray::ForContainer(std::move(values));
-    }
-  });
-  return new_varray;
-}
-
-/**
- * A virtual array implementation for the conversion of spline attributes to control point
- * attributes. The goal is to avoid copying the spline value for every one of its control points
- * unless it is necessary (in that case the materialize functions will be called).
- */
-template class VArray_For_SplineToPoint final : public VArrayImpl {
-  GVArray original_varray_;
-  /* Store existing data materialized if it was not already a span. This is expected
-   * to be worth it because a single spline's value will likely be accessed many times. */
-  VArraySpan original_data_;
-  Array offsets_;
-
- public:
-  VArray_For_SplineToPoint(GVArray original_varray, Array offsets)
-      : VArrayImpl(offsets.last()),
-        original_varray_(std::move(original_varray)),
-        original_data_(original_varray_.typed()),
-        offsets_(std::move(offsets))
-  {
-  }
-
-  T get(const int64_t index) const final
-  {
-    const PointIndices indices = lookup_point_indices(offsets_, index);
-    return original_data_[indices.spline_index];
-  }
-
-  void materialize(const IndexMask mask, MutableSpan r_span) const final
-  {
-    const int total_num = offsets_.last();
-    if (mask.is_range() && mask.as_range() == IndexRange(total_num)) {
-      for (const int spline_index : original_data_.index_range()) {
-        const int offset = offsets_[spline_index];
-        const int next_offset = offsets_[spline_index + 1];
-        r_span.slice(offset, next_offset - offset).fill(original_data_[spline_index]);
-      }
-    }
-    else {
-      int spline_index = 0;
-      for (const int dst_index : mask) {
-        while (offsets_[spline_index] < dst_index) {
-          spline_index++;
-        }
-        r_span[dst_index] = original_data_[spline_index];
-      }
-    }
-  }
-
-  void materialize_to_uninitialized(const IndexMask mask, MutableSpan r_span) const final
-  {
-    T *dst = r_span.data();
-    const int total_num = offsets_.last();
-    if (mask.is_range() && mask.as_range() == IndexRange(total_num)) {
-      for (const int spline_index : original_data_.index_range()) {
-        const int offset = offsets_[spline_index];
-        const int next_offset = offsets_[spline_index + 1];
-        uninitialized_fill_n(dst + offset, next_offset - offset, original_data_[spline_index]);
-      }
-    }
-    else {
-      int spline_index = 0;
-      for (const int dst_index : mask) {
-        while (offsets_[spline_index] < dst_index) {
-          spline_index++;
-        }
-        new (dst + dst_index) T(original_data_[spline_index]);
-      }
-    }
-  }
-};
-
-static GVArray adapt_curve_domain_spline_to_point(const CurveEval &curve, GVArray varray)
-{
-  GVArray new_varray;
-  attribute_math::convert_to_static_type(varray.type(), [&](auto dummy) {
-    using T = decltype(dummy);
-
-    Array offsets = curve.control_point_offsets();
-    new_varray = VArray::template For>(std::move(varray),
-                                                                      std::move(offsets));
-  });
-  return new_varray;
-}
-
-}  // namespace blender::bke
-
-static GVArray adapt_curve_attribute_domain(const CurveEval &curve,
-                                            const GVArray &varray,
-                                            const eAttrDomain from_domain,
-                                            const eAttrDomain to_domain)
-{
-  if (!varray) {
-    return {};
-  }
-  if (varray.is_empty()) {
-    return {};
-  }
-  if (from_domain == to_domain) {
-    return varray;
-  }
-
-  if (from_domain == ATTR_DOMAIN_POINT && to_domain == ATTR_DOMAIN_CURVE) {
-    return blender::bke::adapt_curve_domain_point_to_spline(curve, std::move(varray));
-  }
-  if (from_domain == ATTR_DOMAIN_CURVE && to_domain == ATTR_DOMAIN_POINT) {
-    return blender::bke::adapt_curve_domain_spline_to_point(curve, std::move(varray));
-  }
-
-  return {};
-}
-
-/** \} */
-
-namespace blender::bke {
-
-/* -------------------------------------------------------------------- */
-/** \name Builtin Spline Attributes
- *
- * Attributes with a value for every spline, stored contiguously or in every spline separately.
- * \{ */
-
-class BuiltinSplineAttributeProvider final : public BuiltinAttributeProvider {
-  using AsReadAttribute = GVArray (*)(const CurveEval &data);
-  using AsWriteAttribute = GVMutableArray (*)(CurveEval &data);
-  const AsReadAttribute as_read_attribute_;
-  const AsWriteAttribute as_write_attribute_;
-
- public:
-  BuiltinSplineAttributeProvider(std::string attribute_name,
-                                 const eCustomDataType attribute_type,
-                                 const WritableEnum writable,
-                                 const AsReadAttribute as_read_attribute,
-                                 const AsWriteAttribute as_write_attribute)
-      : BuiltinAttributeProvider(std::move(attribute_name),
-                                 ATTR_DOMAIN_CURVE,
-                                 attribute_type,
-                                 BuiltinAttributeProvider::NonCreatable,
-                                 writable,
-                                 BuiltinAttributeProvider::NonDeletable),
-        as_read_attribute_(as_read_attribute),
-        as_write_attribute_(as_write_attribute)
-  {
-  }
-
-  GVArray try_get_for_read(const void *owner) const final
-  {
-    const CurveEval *curve = static_cast(owner);
-    if (curve == nullptr) {
-      return {};
-    }
-    return as_read_attribute_(*curve);
-  }
-
-  GAttributeWriter try_get_for_write(void *owner) const final
-  {
-    if (writable_ != Writable) {
-      return {};
-    }
-    CurveEval *curve = static_cast(owner);
-    if (curve == nullptr) {
-      return {};
-    }
-    return {as_write_attribute_(*curve), domain_};
-  }
-
-  bool try_delete(void *UNUSED(owner)) const final
-  {
-    return false;
-  }
-
-  bool try_create(void *UNUSED(owner), const AttributeInit &UNUSED(initializer)) const final
-  {
-    return false;
-  }
-
-  bool exists(const void *owner) const final
-  {
-    const CurveEval *curve = static_cast(owner);
-    return !curve->splines().is_empty();
-  }
-};
-
-static int get_spline_resolution(const SplinePtr &spline)
-{
-  if (const BezierSpline *bezier_spline = dynamic_cast(spline.get())) {
-    return bezier_spline->resolution();
-  }
-  if (const NURBSpline *nurb_spline = dynamic_cast(spline.get())) {
-    return nurb_spline->resolution();
-  }
-  return 1;
-}
-
-static void set_spline_resolution(SplinePtr &spline, const int resolution)
-{
-  if (BezierSpline *bezier_spline = dynamic_cast(spline.get())) {
-    bezier_spline->set_resolution(std::max(resolution, 1));
-  }
-  if (NURBSpline *nurb_spline = dynamic_cast(spline.get())) {
-    nurb_spline->set_resolution(std::max(resolution, 1));
-  }
-}
-
-static GVArray make_resolution_read_attribute(const CurveEval &curve)
-{
-  return VArray::ForDerivedSpan(curve.splines());
-}
-
-static GVMutableArray make_resolution_write_attribute(CurveEval &curve)
-{
-  return VMutableArray::
-      ForDerivedSpan(curve.splines());
-}
-
-static bool get_cyclic_value(const SplinePtr &spline)
-{
-  return spline->is_cyclic();
-}
-
-static void set_cyclic_value(SplinePtr &spline, const bool value)
-{
-  if (spline->is_cyclic() != value) {
-    spline->set_cyclic(value);
-    spline->mark_cache_invalid();
-  }
-}
-
-static GVArray make_cyclic_read_attribute(const CurveEval &curve)
-{
-  return VArray::ForDerivedSpan(curve.splines());
-}
-
-static GVMutableArray make_cyclic_write_attribute(CurveEval &curve)
-{
-  return VMutableArray::ForDerivedSpan(
-      curve.splines());
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Builtin Control Point Attributes
- *
- * Attributes with a value for every control point. Most of the complexity here is due to the fact
- * that we must provide access to the attribute data as if it was a contiguous array when it is
- * really stored separately on each spline. That will be inherently rather slow, but these virtual
- * array implementations try to make it workable in common situations.
- * \{ */
-
-/**
- * Individual spans in \a data may be empty if that spline contains no data for the attribute.
- */
-template
-static void point_attribute_materialize(Span> data,
-                                        Span offsets,
-                                        const IndexMask mask,
-                                        MutableSpan r_span)
-{
-  const int total_num = offsets.last();
-  if (mask.is_range() && mask.as_range() == IndexRange(total_num)) {
-    for (const int spline_index : data.index_range()) {
-      const int offset = offsets[spline_index];
-      const int next_offset = offsets[spline_index + 1];
-
-      Span src = data[spline_index];
-      MutableSpan dst = r_span.slice(offset, next_offset - offset);
-      if (src.is_empty()) {
-        dst.fill(T());
-      }
-      else {
-        dst.copy_from(src);
-      }
-    }
-  }
-  else {
-    int spline_index = 0;
-    for (const int dst_index : mask) {
-      /* Skip splines that don't have any control points in the mask. */
-      while (dst_index >= offsets[spline_index + 1]) {
-        spline_index++;
-      }
-
-      const int index_in_spline = dst_index - offsets[spline_index];
-      Span src = data[spline_index];
-      if (src.is_empty()) {
-        r_span[dst_index] = T();
-      }
-      else {
-        r_span[dst_index] = src[index_in_spline];
-      }
-    }
-  }
-}
-
-/**
- * Individual spans in \a data may be empty if that spline contains no data for the attribute.
- */
-template
-static void point_attribute_materialize_to_uninitialized(Span> data,
-                                                         Span offsets,
-                                                         const IndexMask mask,
-                                                         MutableSpan r_span)
-{
-  T *dst = r_span.data();
-  const int total_num = offsets.last();
-  if (mask.is_range() && mask.as_range() == IndexRange(total_num)) {
-    for (const int spline_index : data.index_range()) {
-      const int offset = offsets[spline_index];
-      const int next_offset = offsets[spline_index + 1];
-
-      Span src = data[spline_index];
-      if (src.is_empty()) {
-        uninitialized_fill_n(dst + offset, next_offset - offset, T());
-      }
-      else {
-        uninitialized_copy_n(src.data(), next_offset - offset, dst + offset);
-      }
-    }
-  }
-  else {
-    int spline_index = 0;
-    for (const int dst_index : mask) {
-      /* Skip splines that don't have any control points in the mask. */
-      while (dst_index >= offsets[spline_index + 1]) {
-        spline_index++;
-      }
-
-      const int index_in_spline = dst_index - offsets[spline_index];
-      Span src = data[spline_index];
-      if (src.is_empty()) {
-        new (dst + dst_index) T();
-      }
-      else {
-        new (dst + dst_index) T(src[index_in_spline]);
-      }
-    }
-  }
-}
-
-static GVArray varray_from_initializer(const AttributeInit &initializer,
-                                       const eCustomDataType data_type,
-                                       const Span splines)
-{
-  switch (initializer.type) {
-    case AttributeInit::Type::Default:
-      /* This function shouldn't be called in this case, since there
-       * is no need to copy anything to the new custom data array. */
-      BLI_assert_unreachable();
-      return {};
-    case AttributeInit::Type::VArray:
-      return static_cast(initializer).varray;
-    case AttributeInit::Type::MoveArray:
-      int total_num = 0;
-      for (const SplinePtr &spline : splines) {
-        total_num += spline->size();
-      }
-      return GVArray::ForSpan(GSpan(*bke::custom_data_type_to_cpp_type(data_type),
-                                    static_cast(initializer).data,
-                                    total_num));
-  }
-  BLI_assert_unreachable();
-  return {};
-}
-
-static bool create_point_attribute(CurveEval *curve,
-                                   const AttributeIDRef &attribute_id,
-                                   const AttributeInit &initializer,
-                                   const eCustomDataType data_type)
-{
-  if (curve == nullptr || curve->splines().size() == 0) {
-    return false;
-  }
-
-  MutableSpan splines = curve->splines();
-
-  /* First check the one case that allows us to avoid copying the input data. */
-  if (splines.size() == 1 && initializer.type == AttributeInit::Type::MoveArray) {
-    void *source_data = static_cast(initializer).data;
-    if (!splines.first()->attributes.create_by_move(attribute_id, data_type, source_data)) {
-      MEM_freeN(source_data);
-      return false;
-    }
-    return true;
-  }
-
-  /* Otherwise just create a custom data layer on each of the splines. */
-  for (const int i : splines.index_range()) {
-    if (!splines[i]->attributes.create(attribute_id, data_type)) {
-      /* If attribute creation fails on one of the splines, we cannot leave the custom data
-       * layers in the previous splines around, so delete them before returning. However,
-       * this is not an expected case. */
-      BLI_assert_unreachable();
-      return false;
-    }
-  }
-
-  /* With a default initializer type, we can keep the values at their initial values. */
-  if (initializer.type == AttributeInit::Type::Default) {
-    return true;
-  }
-
-  GAttributeWriter write_attribute = curve->attributes_for_write().lookup_for_write(attribute_id);
-  /* We just created the attribute, it should exist. */
-  BLI_assert(write_attribute);
-
-  GVArray source_varray = varray_from_initializer(initializer, data_type, splines);
-  /* TODO: When we can call a variant of #set_all with a virtual array argument,
-   * this theoretically unnecessary materialize step could be removed. */
-  GVArraySpan source_VArraySpan{source_varray};
-  write_attribute.varray.set_all(source_VArraySpan.data());
-  write_attribute.finish();
-
-  if (initializer.type == AttributeInit::Type::MoveArray) {
-    MEM_freeN(static_cast(initializer).data);
-  }
-
-  return true;
-}
-
-static bool remove_point_attribute(CurveEval *curve, const AttributeIDRef &attribute_id)
-{
-  if (curve == nullptr) {
-    return false;
-  }
-
-  /* Reuse the boolean for all splines; we expect all splines to have the same attributes. */
-  bool layer_freed = false;
-  for (SplinePtr &spline : curve->splines()) {
-    layer_freed = spline->attributes.remove(attribute_id);
-  }
-  return layer_freed;
-}
-
-/**
- * Mutable virtual array for any control point data accessed with spans and an offset array.
- */
-template class VArrayImpl_For_SplinePoints final : public VMutableArrayImpl {
- private:
-  Array> data_;
-  Array offsets_;
-
- public:
-  VArrayImpl_For_SplinePoints(Array> data, Array offsets)
-      : VMutableArrayImpl(offsets.last()), data_(std::move(data)), offsets_(std::move(offsets))
-  {
-  }
-
-  T get(const int64_t index) const final
-  {
-    const PointIndices indices = lookup_point_indices(offsets_, index);
-    return data_[indices.spline_index][indices.point_index];
-  }
-
-  void set(const int64_t index, T value) final
-  {
-    const PointIndices indices = lookup_point_indices(offsets_, index);
-    data_[indices.spline_index][indices.point_index] = value;
-  }
-
-  void set_all(Span src) final
-  {
-    for (const int spline_index : data_.index_range()) {
-      const int offset = offsets_[spline_index];
-      const int next_offsets = offsets_[spline_index + 1];
-      data_[spline_index].copy_from(src.slice(offset, next_offsets - offset));
-    }
-  }
-
-  void materialize(const IndexMask mask, MutableSpan r_span) const final
-  {
-    point_attribute_materialize({(Span *)data_.data(), data_.size()}, offsets_, mask, r_span);
-  }
-
-  void materialize_to_uninitialized(const IndexMask mask, MutableSpan r_span) const final
-  {
-    point_attribute_materialize_to_uninitialized(
-        {(Span *)data_.data(), data_.size()}, offsets_, mask, r_span);
-  }
-};
-
-template VArray point_data_varray(Array> spans, Array offsets)
-{
-  return VArray::template For>(std::move(spans),
-                                                                 std::move(offsets));
-}
-
-template
-VMutableArray point_data_varray_mutable(Array> spans, Array offsets)
-{
-  return VMutableArray::template For>(std::move(spans),
-                                                                        std::move(offsets));
-}
-
-/**
- * Virtual array implementation specifically for control point positions. This is only needed for
- * Bezier splines, where adjusting the position also requires adjusting handle positions depending
- * on handle types. We pay a small price for this when other spline types are mixed with Bezier.
- *
- * \note There is no need to check the handle type to avoid changing auto handles, since
- * retrieving write access to the position data will mark them for recomputation anyway.
- */
-class VArrayImpl_For_SplinePosition final : public VMutableArrayImpl {
- private:
-  MutableSpan splines_;
-  Array offsets_;
-
- public:
-  VArrayImpl_For_SplinePosition(MutableSpan splines, Array offsets)
-      : VMutableArrayImpl(offsets.last()), splines_(splines), offsets_(std::move(offsets))
-  {
-  }
-
-  float3 get(const int64_t index) const final
-  {
-    const PointIndices indices = lookup_point_indices(offsets_, index);
-    return splines_[indices.spline_index]->positions()[indices.point_index];
-  }
-
-  void set(const int64_t index, float3 value) final
-  {
-    const PointIndices indices = lookup_point_indices(offsets_, index);
-    Spline &spline = *splines_[indices.spline_index];
-    spline.positions()[indices.point_index] = value;
-  }
-
-  void set_all(Span src) final
-  {
-    for (const int spline_index : splines_.index_range()) {
-      Spline &spline = *splines_[spline_index];
-      const int offset = offsets_[spline_index];
-      const int next_offset = offsets_[spline_index + 1];
-      spline.positions().copy_from(src.slice(offset, next_offset - offset));
-    }
-  }
-
-  /** Utility so we can pass positions to the materialize functions above. */
-  Array> get_position_spans() const
-  {
-    Array> spans(splines_.size());
-    for (const int i : spans.index_range()) {
-      spans[i] = splines_[i]->positions();
-    }
-    return spans;
-  }
-
-  void materialize(const IndexMask mask, MutableSpan r_span) const final
-  {
-    Array> spans = this->get_position_spans();
-    point_attribute_materialize(spans.as_span(), offsets_, mask, r_span);
-  }
-
-  void materialize_to_uninitialized(const IndexMask mask, MutableSpan r_span) const final
-  {
-    Array> spans = this->get_position_spans();
-    point_attribute_materialize_to_uninitialized(spans.as_span(), offsets_, mask, r_span);
-  }
-};
-
-class VArrayImpl_For_BezierHandles final : public VMutableArrayImpl {
- private:
-  MutableSpan splines_;
-  Array offsets_;
-  bool is_right_;
-
- public:
-  VArrayImpl_For_BezierHandles(MutableSpan splines,
-                               Array offsets,
-                               const bool is_right)
-      : VMutableArrayImpl(offsets.last()),
-        splines_(splines),
-        offsets_(std::move(offsets)),
-        is_right_(is_right)
-  {
-  }
-
-  float3 get(const int64_t index) const final
-  {
-    const PointIndices indices = lookup_point_indices(offsets_, index);
-    const Spline &spline = *splines_[indices.spline_index];
-    if (spline.type() == CURVE_TYPE_BEZIER) {
-      const BezierSpline &bezier_spline = static_cast(spline);
-      return is_right_ ? bezier_spline.handle_positions_right()[indices.point_index] :
-                         bezier_spline.handle_positions_left()[indices.point_index];
-    }
-    return float3(0);
-  }
-
-  void set(const int64_t index, float3 value) final
-  {
-    const PointIndices indices = lookup_point_indices(offsets_, index);
-    Spline &spline = *splines_[indices.spline_index];
-    if (spline.type() == CURVE_TYPE_BEZIER) {
-      BezierSpline &bezier_spline = static_cast(spline);
-      if (is_right_) {
-        bezier_spline.handle_positions_right()[indices.point_index] = value;
-      }
-      else {
-        bezier_spline.handle_positions_left()[indices.point_index] = value;
-      }
-      bezier_spline.mark_cache_invalid();
-    }
-  }
-
-  void set_all(Span src) final
-  {
-    for (const int spline_index : splines_.index_range()) {
-      Spline &spline = *splines_[spline_index];
-      if (spline.type() == CURVE_TYPE_BEZIER) {
-        const int offset = offsets_[spline_index];
-
-        BezierSpline &bezier_spline = static_cast(spline);
-        if (is_right_) {
-          for (const int i : IndexRange(bezier_spline.size())) {
-            bezier_spline.handle_positions_right()[i] = src[offset + i];
-          }
-        }
-        else {
-          for (const int i : IndexRange(bezier_spline.size())) {
-            bezier_spline.handle_positions_left()[i] = src[offset + i];
-          }
-        }
-        bezier_spline.mark_cache_invalid();
-      }
-    }
-  }
-
-  void materialize(const IndexMask mask, MutableSpan r_span) const final
-  {
-    Array> spans = get_handle_spans(splines_, is_right_);
-    point_attribute_materialize(spans.as_span(), offsets_, mask, r_span);
-  }
-
-  void materialize_to_uninitialized(const IndexMask mask, MutableSpan r_span) const final
-  {
-    Array> spans = get_handle_spans(splines_, is_right_);
-    point_attribute_materialize_to_uninitialized(spans.as_span(), offsets_, mask, r_span);
-  }
-
-  /**
-   * Utility so we can pass handle positions to the materialize functions above.
-   *
-   * \note This relies on the ability of the materialize implementations to
-   * handle empty spans, since only Bezier splines have handles.
-   */
-  static Array> get_handle_spans(Span splines, const bool is_right)
-  {
-    Array> spans(splines.size());
-    for (const int i : spans.index_range()) {
-      if (splines[i]->type() == CURVE_TYPE_BEZIER) {
-        BezierSpline &bezier_spline = static_cast(*splines[i]);
-        spans[i] = is_right ? bezier_spline.handle_positions_right() :
-                              bezier_spline.handle_positions_left();
-      }
-      else {
-        spans[i] = {};
-      }
-    }
-    return spans;
-  }
-};
-
-/**
- * Provider for any builtin control point attribute that doesn't need
- * special handling like access to other arrays in the spline.
- */
-template class BuiltinPointAttributeProvider : public BuiltinAttributeProvider {
- protected:
-  using GetSpan = Span (*)(const Spline &spline);
-  using GetMutableSpan = MutableSpan (*)(Spline &spline);
-  using UpdateOnWrite = void (*)(Spline &spline);
-  const GetSpan get_span_;
-  const GetMutableSpan get_mutable_span_;
-  const UpdateOnWrite update_on_write_;
-  bool stored_in_custom_data_;
-
- public:
-  BuiltinPointAttributeProvider(std::string attribute_name,
-                                const CreatableEnum creatable,
-                                const DeletableEnum deletable,
-                                const GetSpan get_span,
-                                const GetMutableSpan get_mutable_span,
-                                const UpdateOnWrite update_on_write,
-                                const bool stored_in_custom_data)
-      : BuiltinAttributeProvider(std::move(attribute_name),
-                                 ATTR_DOMAIN_POINT,
-                                 bke::cpp_type_to_custom_data_type(CPPType::get()),
-                                 creatable,
-                                 WritableEnum::Writable,
-                                 deletable),
-        get_span_(get_span),
-        get_mutable_span_(get_mutable_span),
-        update_on_write_(update_on_write),
-        stored_in_custom_data_(stored_in_custom_data)
-  {
-  }
-
-  GVArray try_get_for_read(const void *owner) const override
-  {
-    const CurveEval *curve = static_cast(owner);
-    if (curve == nullptr) {
-      return {};
-    }
-
-    if (!this->exists(owner)) {
-      return {};
-    }
-
-    Span splines = curve->splines();
-    if (splines.size() == 1) {
-      return GVArray::ForSpan(get_span_(*splines.first()));
-    }
-
-    Array offsets = curve->control_point_offsets();
-    Array> spans(splines.size());
-    for (const int i : splines.index_range()) {
-      Span span = get_span_(*splines[i]);
-      /* Use const-cast because the underlying virtual array implementation is shared between const
-       * and non const data. */
-      spans[i] = MutableSpan(const_cast(span.data()), span.size());
-    }
-
-    return point_data_varray(spans, offsets);
-  }
-
-  GAttributeWriter try_get_for_write(void *owner) const override
-  {
-    CurveEval *curve = static_cast(owner);
-    if (curve == nullptr) {
-      return {};
-    }
-
-    if (!this->exists(owner)) {
-      return {};
-    }
-
-    std::function tag_modified_fn;
-    if (update_on_write_ != nullptr) {
-      tag_modified_fn = [curve, update = update_on_write_]() {
-        for (SplinePtr &spline : curve->splines()) {
-          update(*spline);
-        }
-      };
-    }
-
-    MutableSpan splines = curve->splines();
-    if (splines.size() == 1) {
-      return {GVMutableArray::ForSpan(get_mutable_span_(*splines.first())),
-              domain_,
-              std::move(tag_modified_fn)};
-    }
-
-    Array offsets = curve->control_point_offsets();
-    Array> spans(splines.size());
-    for (const int i : splines.index_range()) {
-      spans[i] = get_mutable_span_(*splines[i]);
-    }
-
-    return {point_data_varray_mutable(spans, offsets), domain_, tag_modified_fn};
-  }
-
-  bool try_delete(void *owner) const final
-  {
-    if (deletable_ == DeletableEnum::NonDeletable) {
-      return false;
-    }
-    CurveEval *curve = static_cast(owner);
-    return remove_point_attribute(curve, name_);
-  }
-
-  bool try_create(void *owner, const AttributeInit &initializer) const final
-  {
-    if (createable_ == CreatableEnum::NonCreatable) {
-      return false;
-    }
-    CurveEval *curve = static_cast(owner);
-    return create_point_attribute(curve, name_, initializer, CD_PROP_INT32);
-  }
-
-  bool exists(const void *owner) const final
-  {
-    const CurveEval *curve = static_cast(owner);
-    if (curve == nullptr) {
-      return false;
-    }
-
-    Span splines = curve->splines();
-    if (splines.size() == 0) {
-      return false;
-    }
-
-    if (stored_in_custom_data_) {
-      if (!curve->splines().first()->attributes.get_for_read(name_)) {
-        return false;
-      }
-    }
-
-    bool has_point = false;
-    for (const SplinePtr &spline : curve->splines()) {
-      if (spline->size() != 0) {
-        has_point = true;
-        break;
-      }
-    }
-
-    if (!has_point) {
-      return false;
-    }
-
-    return true;
-  }
-};
-
-/**
- * Special attribute provider for the position attribute. Keeping this separate means we don't
- * need to make #BuiltinPointAttributeProvider overly generic, and the special handling for the
- * positions is more clear.
- */
-class PositionAttributeProvider final : public BuiltinPointAttributeProvider {
- public:
-  PositionAttributeProvider()
-      : BuiltinPointAttributeProvider(
-            "position",
-            BuiltinAttributeProvider::NonCreatable,
-            BuiltinAttributeProvider::NonDeletable,
-            [](const Spline &spline) { return spline.positions(); },
-            [](Spline &spline) { return spline.positions(); },
-            [](Spline &spline) { spline.mark_cache_invalid(); },
-            false)
-  {
-  }
-
-  GAttributeWriter try_get_for_write(void *owner) const final
-  {
-    CurveEval *curve = static_cast(owner);
-    if (curve == nullptr) {
-      return {};
-    }
-
-    /* Use the regular position virtual array when there aren't any Bezier splines
-     * to avoid the overhead of checking the spline type for every point. */
-    if (!curve->has_spline_with_type(CURVE_TYPE_BEZIER)) {
-      return BuiltinPointAttributeProvider::try_get_for_write(owner);
-    }
-
-    auto tag_modified_fn = [curve]() {
-      /* Changing the positions requires recalculation of cached evaluated data in many cases.
-       * This could set more specific flags in the future to avoid unnecessary recomputation. */
-      curve->mark_cache_invalid();
-    };
-
-    Array offsets = curve->control_point_offsets();
-    return {VMutableArray::For(curve->splines(),
-                                                                      std::move(offsets)),
-            domain_,
-            tag_modified_fn};
-  }
-};
-
-class BezierHandleAttributeProvider : public BuiltinAttributeProvider {
- private:
-  bool is_right_;
-
- public:
-  BezierHandleAttributeProvider(const bool is_right)
-      : BuiltinAttributeProvider(is_right ? "handle_right" : "handle_left",
-                                 ATTR_DOMAIN_POINT,
-                                 CD_PROP_FLOAT3,
-                                 BuiltinAttributeProvider::NonCreatable,
-                                 BuiltinAttributeProvider::Writable,
-                                 BuiltinAttributeProvider::NonDeletable),
-        is_right_(is_right)
-  {
-  }
-
-  GVArray try_get_for_read(const void *owner) const override
-  {
-    const CurveEval *curve = static_cast(owner);
-    if (curve == nullptr) {
-      return {};
-    }
-
-    if (!curve->has_spline_with_type(CURVE_TYPE_BEZIER)) {
-      return {};
-    }
-
-    Array offsets = curve->control_point_offsets();
-    /* Use const-cast because the underlying virtual array implementation is shared between const
-     * and non const data. */
-    return VArray::For(
-        const_cast(curve)->splines(), std::move(offsets), is_right_);
-  }
-
-  GAttributeWriter try_get_for_write(void *owner) const override
-  {
-    CurveEval *curve = static_cast(owner);
-    if (curve == nullptr) {
-      return {};
-    }
-
-    if (!curve->has_spline_with_type(CURVE_TYPE_BEZIER)) {
-      return {};
-    }
-
-    auto tag_modified_fn = [curve]() { curve->mark_cache_invalid(); };
-
-    Array offsets = curve->control_point_offsets();
-    return {VMutableArray::For(
-                curve->splines(), std::move(offsets), is_right_),
-            domain_,
-            tag_modified_fn};
-  }
-
-  bool try_delete(void *UNUSED(owner)) const final
-  {
-    return false;
-  }
-
-  bool try_create(void *UNUSED(owner), const AttributeInit &UNUSED(initializer)) const final
-  {
-    return false;
-  }
-
-  bool exists(const void *owner) const final
-  {
-    const CurveEval *curve = static_cast(owner);
-    if (curve == nullptr) {
-      return false;
-    }
-
-    CurveComponentLegacy component;
-    component.replace(const_cast(curve), GeometryOwnershipType::ReadOnly);
-
-    return curve->has_spline_with_type(CURVE_TYPE_BEZIER) && !curve->splines().is_empty();
-  }
-};
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Dynamic Control Point Attributes
- *
- * The dynamic control point attribute implementation is very similar to the builtin attribute
- * implementation-- it uses the same virtual array types. In order to work, this code depends on
- * the fact that all a curve's splines will have the same attributes and they all have the same
- * type.
- * \{ */
-
-class DynamicPointAttributeProvider final : public DynamicAttributesProvider {
- private:
-  static constexpr uint64_t supported_types_mask = CD_MASK_PROP_FLOAT | CD_MASK_PROP_FLOAT2 |
-                                                   CD_MASK_PROP_FLOAT3 | CD_MASK_PROP_INT32 |
-                                                   CD_MASK_PROP_COLOR | CD_MASK_PROP_BOOL |
-                                                   CD_MASK_PROP_INT8;
-
- public:
-  GAttributeReader try_get_for_read(const void *owner,
-                                    const AttributeIDRef &attribute_id) const final
-  {
-    const CurveEval *curve = static_cast(owner);
-    if (curve == nullptr || curve->splines().size() == 0) {
-      return {};
-    }
-
-    Span splines = curve->splines();
-    Vector spans; /* GSpan has no default constructor. */
-    spans.reserve(splines.size());
-    std::optional first_span = splines[0]->attributes.get_for_read(attribute_id);
-    if (!first_span) {
-      return {};
-    }
-    spans.append(*first_span);
-    for (const int i : IndexRange(1, splines.size() - 1)) {
-      std::optional span = splines[i]->attributes.get_for_read(attribute_id);
-      if (!span) {
-        /* All splines should have the same set of data layers. It would be possible to recover
-         * here and return partial data instead, but that would add a lot of complexity for a
-         * situation we don't even expect to encounter. */
-        BLI_assert_unreachable();
-        return {};
-      }
-      if (span->type() != spans.last().type()) {
-        /* Data layer types on separate splines do not match. */
-        BLI_assert_unreachable();
-        return {};
-      }
-      spans.append(*span);
-    }
-
-    /* First check for the simpler situation when we can return a simpler span virtual array. */
-    if (spans.size() == 1) {
-      return {GVArray::ForSpan(spans.first()), ATTR_DOMAIN_POINT};
-    }
-
-    GAttributeReader attribute = {};
-    Array offsets = curve->control_point_offsets();
-    attribute_math::convert_to_static_type(spans[0].type(), [&](auto dummy) {
-      using T = decltype(dummy);
-      Array> data(splines.size());
-      for (const int i : splines.index_range()) {
-        Span span = spans[i].typed();
-        /* Use const-cast because the underlying virtual array implementation is shared between
-         * const and non const data. */
-        data[i] = MutableSpan(const_cast(span.data()), span.size());
-        BLI_assert(data[i].data() != nullptr);
-      }
-      attribute = {point_data_varray(data, offsets), ATTR_DOMAIN_POINT};
-    });
-    return attribute;
-  }
-
-  /* This function is almost the same as #try_get_for_read, but without const. */
-  GAttributeWriter try_get_for_write(void *owner, const AttributeIDRef &attribute_id) const final
-  {
-    CurveEval *curve = static_cast(owner);
-    if (curve == nullptr || curve->splines().size() == 0) {
-      return {};
-    }
-
-    MutableSpan splines = curve->splines();
-    Vector spans; /* GMutableSpan has no default constructor. */
-    spans.reserve(splines.size());
-    std::optional first_span = splines[0]->attributes.get_for_write(attribute_id);
-    if (!first_span) {
-      return {};
-    }
-    spans.append(*first_span);
-    for (const int i : IndexRange(1, splines.size() - 1)) {
-      std::optional span = splines[i]->attributes.get_for_write(attribute_id);
-      if (!span) {
-        /* All splines should have the same set of data layers. It would be possible to recover
-         * here and return partial data instead, but that would add a lot of complexity for a
-         * situation we don't even expect to encounter. */
-        BLI_assert_unreachable();
-        return {};
-      }
-      if (span->type() != spans.last().type()) {
-        /* Data layer types on separate splines do not match. */
-        BLI_assert_unreachable();
-        return {};
-      }
-      spans.append(*span);
-    }
-
-    /* First check for the simpler situation when we can return a simpler span virtual array. */
-    if (spans.size() == 1) {
-      return {GVMutableArray::ForSpan(spans.first()), ATTR_DOMAIN_POINT};
-    }
-
-    GAttributeWriter attribute = {};
-    Array offsets = curve->control_point_offsets();
-    attribute_math::convert_to_static_type(spans[0].type(), [&](auto dummy) {
-      using T = decltype(dummy);
-      Array> data(splines.size());
-      for (const int i : splines.index_range()) {
-        data[i] = spans[i].typed();
-        BLI_assert(data[i].data() != nullptr);
-      }
-      attribute = {point_data_varray_mutable(data, offsets), ATTR_DOMAIN_POINT};
-    });
-    return attribute;
-  }
-
-  bool try_delete(void *owner, const AttributeIDRef &attribute_id) const final
-  {
-    CurveEval *curve = static_cast(owner);
-    return remove_point_attribute(curve, attribute_id);
-  }
-
-  bool try_create(void *owner,
-                  const AttributeIDRef &attribute_id,
-                  const eAttrDomain domain,
-                  const eCustomDataType data_type,
-                  const AttributeInit &initializer) const final
-  {
-    BLI_assert(this->type_is_supported(data_type));
-    if (domain != ATTR_DOMAIN_POINT) {
-      return false;
-    }
-    CurveEval *curve = static_cast(owner);
-    return create_point_attribute(curve, attribute_id, initializer, data_type);
-  }
-
-  bool foreach_attribute(const void *owner, const AttributeForeachCallback callback) const final
-  {
-    const CurveEval *curve = static_cast(owner);
-    if (curve == nullptr || curve->splines().size() == 0) {
-      return false;
-    }
-
-    Span splines = curve->splines();
-
-    /* In a debug build, check that all corresponding custom data layers have the same type. */
-    curve->assert_valid_point_attributes();
-
-    /* Use the first spline as a representative for all the others. */
-    splines.first()->attributes.foreach_attribute(callback, ATTR_DOMAIN_POINT);
-
-    return true;
-  }
-
-  void foreach_domain(const FunctionRef callback) const final
-  {
-    callback(ATTR_DOMAIN_POINT);
-  }
-
-  bool type_is_supported(eCustomDataType data_type) const
-  {
-    return ((1ULL << data_type) & supported_types_mask) != 0;
-  }
-};
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Attribute Provider Declaration
- * \{ */
-
-/**
- * In this function all the attribute providers for a curve component are created.
- * Most data in this function is statically allocated, because it does not change over time.
- */
-static ComponentAttributeProviders create_attribute_providers_for_curve()
-{
-  static BuiltinSplineAttributeProvider resolution("resolution",
-                                                   CD_PROP_INT32,
-                                                   BuiltinAttributeProvider::Writable,
-                                                   make_resolution_read_attribute,
-                                                   make_resolution_write_attribute);
-
-  static BuiltinSplineAttributeProvider cyclic("cyclic",
-                                               CD_PROP_BOOL,
-                                               BuiltinAttributeProvider::Writable,
-                                               make_cyclic_read_attribute,
-                                               make_cyclic_write_attribute);
-
-  static CustomDataAccessInfo spline_custom_data_access = {
-      [](void *owner) -> CustomData * {
-        CurveEval *curve = static_cast(owner);
-        return curve ? &curve->attributes.data : nullptr;
-      },
-      [](const void *owner) -> const CustomData * {
-        const CurveEval *curve = static_cast(owner);
-        return curve ? &curve->attributes.data : nullptr;
-      },
-      [](const void *owner) -> int {
-        const CurveEval *curve = static_cast(owner);
-        return curve->splines().size();
-      },
-      nullptr};
-
-  static CustomDataAttributeProvider spline_custom_data(ATTR_DOMAIN_CURVE,
-                                                        spline_custom_data_access);
-
-  static PositionAttributeProvider position;
-  static BezierHandleAttributeProvider handles_start(false);
-  static BezierHandleAttributeProvider handles_end(true);
-
-  static BuiltinPointAttributeProvider id(
-      "id",
-      BuiltinAttributeProvider::Creatable,
-      BuiltinAttributeProvider::Deletable,
-      [](const Spline &spline) {
-        std::optional span = spline.attributes.get_for_read("id");
-        return span ? span->typed() : Span();
-      },
-      [](Spline &spline) {
-        std::optional span = spline.attributes.get_for_write("id");
-        return span ? span->typed() : MutableSpan();
-      },
-      {},
-      true);
-
-  static BuiltinPointAttributeProvider radius(
-      "radius",
-      BuiltinAttributeProvider::NonCreatable,
-      BuiltinAttributeProvider::NonDeletable,
-      [](const Spline &spline) { return spline.radii(); },
-      [](Spline &spline) { return spline.radii(); },
-      nullptr,
-      false);
-
-  static BuiltinPointAttributeProvider tilt(
-      "tilt",
-      BuiltinAttributeProvider::NonCreatable,
-      BuiltinAttributeProvider::NonDeletable,
-      [](const Spline &spline) { return spline.tilts(); },
-      [](Spline &spline) { return spline.tilts(); },
-      [](Spline &spline) { spline.mark_cache_invalid(); },
-      false);
-
-  static DynamicPointAttributeProvider point_custom_data;
-
-  return ComponentAttributeProviders(
-      {&position, &id, &radius, &tilt, &handles_start, &handles_end, &resolution, &cyclic},
-      {&spline_custom_data, &point_custom_data});
-}
-
-/** \} */
-
-static AttributeAccessorFunctions get_curve_accessor_functions()
-{
-  static const ComponentAttributeProviders providers = create_attribute_providers_for_curve();
-  AttributeAccessorFunctions fn =
-      attribute_accessor_functions::accessor_functions_for_providers();
-  fn.domain_size = [](const void *owner, const eAttrDomain domain) -> int {
-    if (owner == nullptr) {
-      return 0;
-    }
-    const CurveEval &curve_eval = *static_cast(owner);
-    switch (domain) {
-      case ATTR_DOMAIN_POINT:
-        return curve_eval.total_control_point_num();
-      case ATTR_DOMAIN_CURVE:
-        return curve_eval.splines().size();
-      default:
-        return 0;
-    }
-  };
-  fn.domain_supported = [](const void *UNUSED(owner), const eAttrDomain domain) {
-    return ELEM(domain, ATTR_DOMAIN_POINT, ATTR_DOMAIN_CURVE);
-  };
-  fn.adapt_domain = [](const void *owner,
-                       const blender::GVArray &varray,
-                       const eAttrDomain from_domain,
-                       const eAttrDomain to_domain) -> GVArray {
-    if (owner == nullptr) {
-      return {};
-    }
-    const CurveEval &curve_eval = *static_cast(owner);
-    return adapt_curve_attribute_domain(curve_eval, varray, from_domain, to_domain);
-  };
-  return fn;
-}
-
-static const AttributeAccessorFunctions &get_curve_accessor_functions_ref()
-{
-  static const AttributeAccessorFunctions fn = get_curve_accessor_functions();
-  return fn;
-}
-
-}  // namespace blender::bke
-
-std::optional CurveComponentLegacy::attributes() const
-{
-  return blender::bke::AttributeAccessor(curve_, blender::bke::get_curve_accessor_functions_ref());
-}
-
-std::optional CurveComponentLegacy::attributes_for_write()
-{
-  return blender::bke::MutableAttributeAccessor(curve_,
-                                                blender::bke::get_curve_accessor_functions_ref());
-}
-
-blender::bke::MutableAttributeAccessor CurveEval::attributes_for_write()
-{
-  return blender::bke::MutableAttributeAccessor(this,
-                                                blender::bke::get_curve_accessor_functions_ref());
-}
diff --git a/source/blender/blenkernel/intern/geometry_component_curves.cc b/source/blender/blenkernel/intern/geometry_component_curves.cc
index 34c17bedc2c..4ace68546ac 100644
--- a/source/blender/blenkernel/intern/geometry_component_curves.cc
+++ b/source/blender/blenkernel/intern/geometry_component_curves.cc
@@ -12,6 +12,8 @@
 #include "BKE_geometry_set.hh"
 #include "BKE_lib_id.h"
 
+#include "FN_multi_function_builder.hh"
+
 #include "attribute_access_intern.hh"
 
 using blender::GVArray;
@@ -206,18 +208,11 @@ static Array curve_normal_point_domain(const bke::CurvesGeometry &curves
   return results;
 }
 
-VArray curve_normals_varray(const CurveComponent &component, const eAttrDomain domain)
+VArray curve_normals_varray(const CurvesGeometry &curves, const eAttrDomain domain)
 {
-  if (!component.has_curves()) {
-    return {};
-  }
-
-  const Curves &curves_id = *component.get_for_read();
-  const bke::CurvesGeometry &curves = bke::CurvesGeometry::wrap(curves_id.geometry);
-
   const VArray types = curves.curve_types();
   if (curves.is_single_type(CURVE_TYPE_POLY)) {
-    return component.attributes()->adapt_domain(
+    return curves.adapt_domain(
         VArray::ForSpan(curves.evaluated_normals()), ATTR_DOMAIN_POINT, domain);
   }
 
@@ -228,7 +223,7 @@ VArray curve_normals_varray(const CurveComponent &component, const eAttr
   }
 
   if (domain == ATTR_DOMAIN_CURVE) {
-    return component.attributes()->adapt_domain(
+    return curves.adapt_domain(
         VArray::ForContainer(std::move(normals)), ATTR_DOMAIN_POINT, ATTR_DOMAIN_CURVE);
   }
 
@@ -241,15 +236,9 @@ VArray curve_normals_varray(const CurveComponent &component, const eAttr
 /** \name Curve Length Field Input
  * \{ */
 
-static VArray construct_curve_length_gvarray(const CurveComponent &component,
+static VArray construct_curve_length_gvarray(const CurvesGeometry &curves,
                                                     const eAttrDomain domain)
 {
-  if (!component.has_curves()) {
-    return {};
-  }
-  const Curves &curves_id = *component.get_for_read();
-  const bke::CurvesGeometry &curves = bke::CurvesGeometry::wrap(curves_id.geometry);
-
   curves.ensure_evaluated_lengths();
 
   VArray cyclic = curves.cyclic();
@@ -263,28 +252,23 @@ static VArray construct_curve_length_gvarray(const CurveComponent &compon
   }
 
   if (domain == ATTR_DOMAIN_POINT) {
-    return component.attributes()->adapt_domain(
-        std::move(lengths), ATTR_DOMAIN_CURVE, ATTR_DOMAIN_POINT);
+    return curves.adapt_domain(std::move(lengths), ATTR_DOMAIN_CURVE, ATTR_DOMAIN_POINT);
   }
 
   return {};
 }
 
 CurveLengthFieldInput::CurveLengthFieldInput()
-    : GeometryFieldInput(CPPType::get(), "Spline Length node")
+    : CurvesFieldInput(CPPType::get(), "Spline Length node")
 {
   category_ = Category::Generated;
 }
 
-GVArray CurveLengthFieldInput::get_varray_for_context(const GeometryComponent &component,
+GVArray CurveLengthFieldInput::get_varray_for_context(const CurvesGeometry &curves,
                                                       const eAttrDomain domain,
                                                       IndexMask UNUSED(mask)) const
 {
-  if (component.type() == GEO_COMPONENT_TYPE_CURVE) {
-    const CurveComponent &curve_component = static_cast(component);
-    return construct_curve_length_gvarray(curve_component, domain);
-  }
-  return {};
+  return construct_curve_length_gvarray(curves, domain);
 }
 
 uint64_t CurveLengthFieldInput::hash() const
@@ -357,10 +341,6 @@ static ComponentAttributeProviders create_attribute_providers_for_curve()
       [](const void *owner) -> int {
         const CurvesGeometry &curves = *static_cast(owner);
         return curves.curves_num();
-      },
-      [](void *owner) {
-        CurvesGeometry &curves = *static_cast(owner);
-        curves.update_customdata_pointers();
       }};
   static CustomDataAccessInfo point_access = {
       [](void *owner) -> CustomData * {
@@ -374,10 +354,6 @@ static ComponentAttributeProviders create_attribute_providers_for_curve()
       [](const void *owner) -> int {
         const CurvesGeometry &curves = *static_cast(owner);
         return curves.points_num();
-      },
-      [](void *owner) {
-        CurvesGeometry &curves = *static_cast(owner);
-        curves.update_customdata_pointers();
       }};
 
   static BuiltinCustomDataLayerProvider position("position",
@@ -452,6 +428,12 @@ static ComponentAttributeProviders create_attribute_providers_for_curve()
                                                     make_array_write_attribute,
                                                     tag_component_positions_changed);
 
+  static const fn::CustomMF_SI_SO handle_type_clamp{
+      "Handle Type Validate",
+      [](int8_t value) {
+        return std::clamp(value, BEZIER_HANDLE_FREE, BEZIER_HANDLE_ALIGN);
+      },
+      fn::CustomMF_presets::AllSpanOrSingle()};
   static BuiltinCustomDataLayerProvider handle_type_right("handle_type_right",
                                                           ATTR_DOMAIN_POINT,
                                                           CD_PROP_INT8,
@@ -462,7 +444,8 @@ static ComponentAttributeProviders create_attribute_providers_for_curve()
                                                           point_access,
                                                           make_array_read_attribute,
                                                           make_array_write_attribute,
-                                                          tag_component_topology_changed);
+                                                          tag_component_topology_changed,
+                                                          AttributeValidator{&handle_type_clamp});
 
   static BuiltinCustomDataLayerProvider handle_type_left("handle_type_left",
                                                          ATTR_DOMAIN_POINT,
@@ -474,7 +457,8 @@ static ComponentAttributeProviders create_attribute_providers_for_curve()
                                                          point_access,
                                                          make_array_read_attribute,
                                                          make_array_write_attribute,
-                                                         tag_component_topology_changed);
+                                                         tag_component_topology_changed,
+                                                         AttributeValidator{&handle_type_clamp});
 
   static BuiltinCustomDataLayerProvider nurbs_weight("nurbs_weight",
                                                      ATTR_DOMAIN_POINT,
@@ -488,6 +472,10 @@ static ComponentAttributeProviders create_attribute_providers_for_curve()
                                                      make_array_write_attribute,
                                                      tag_component_positions_changed);
 
+  static const fn::CustomMF_SI_SO nurbs_order_clamp{
+      "NURBS Order Validate",
+      [](int8_t value) { return std::max(value, 0); },
+      fn::CustomMF_presets::AllSpanOrSingle()};
   static BuiltinCustomDataLayerProvider nurbs_order("nurbs_order",
                                                     ATTR_DOMAIN_CURVE,
                                                     CD_PROP_INT8,
@@ -498,8 +486,15 @@ static ComponentAttributeProviders create_attribute_providers_for_curve()
                                                     curve_access,
                                                     make_array_read_attribute,
                                                     make_array_write_attribute,
-                                                    tag_component_topology_changed);
+                                                    tag_component_topology_changed,
+                                                    AttributeValidator{&nurbs_order_clamp});
 
+  static const fn::CustomMF_SI_SO normal_mode_clamp{
+      "Normal Mode Validate",
+      [](int8_t value) {
+        return std::clamp(value, NORMAL_MODE_MINIMUM_TWIST, NORMAL_MODE_Z_UP);
+      },
+      fn::CustomMF_presets::AllSpanOrSingle()};
   static BuiltinCustomDataLayerProvider normal_mode("normal_mode",
                                                     ATTR_DOMAIN_CURVE,
                                                     CD_PROP_INT8,
@@ -510,8 +505,15 @@ static ComponentAttributeProviders create_attribute_providers_for_curve()
                                                     curve_access,
                                                     make_array_read_attribute,
                                                     make_array_write_attribute,
-                                                    tag_component_normals_changed);
+                                                    tag_component_normals_changed,
+                                                    AttributeValidator{&normal_mode_clamp});
 
+  static const fn::CustomMF_SI_SO knots_mode_clamp{
+      "Knots Mode Validate",
+      [](int8_t value) {
+        return std::clamp(value, NURBS_KNOT_MODE_NORMAL, NURBS_KNOT_MODE_ENDPOINT_BEZIER);
+      },
+      fn::CustomMF_presets::AllSpanOrSingle()};
   static BuiltinCustomDataLayerProvider nurbs_knots_mode("knots_mode",
                                                          ATTR_DOMAIN_CURVE,
                                                          CD_PROP_INT8,
@@ -522,8 +524,15 @@ static ComponentAttributeProviders create_attribute_providers_for_curve()
                                                          curve_access,
                                                          make_array_read_attribute,
                                                          make_array_write_attribute,
-                                                         tag_component_topology_changed);
+                                                         tag_component_topology_changed,
+                                                         AttributeValidator{&knots_mode_clamp});
 
+  static const fn::CustomMF_SI_SO curve_type_clamp{
+      "Curve Type Validate",
+      [](int8_t value) {
+        return std::clamp(value, CURVE_TYPE_CATMULL_ROM, CURVE_TYPES_NUM);
+      },
+      fn::CustomMF_presets::AllSpanOrSingle()};
   static BuiltinCustomDataLayerProvider curve_type("curve_type",
                                                    ATTR_DOMAIN_CURVE,
                                                    CD_PROP_INT8,
@@ -534,8 +543,13 @@ static ComponentAttributeProviders create_attribute_providers_for_curve()
                                                    curve_access,
                                                    make_array_read_attribute,
                                                    make_array_write_attribute,
-                                                   tag_component_curve_types_changed);
+                                                   tag_component_curve_types_changed,
+                                                   AttributeValidator{&curve_type_clamp});
 
+  static const fn::CustomMF_SI_SO resolution_clamp{
+      "Resolution Validate",
+      [](int value) { return std::max(value, 1); },
+      fn::CustomMF_presets::AllSpanOrSingle()};
   static BuiltinCustomDataLayerProvider resolution("resolution",
                                                    ATTR_DOMAIN_CURVE,
                                                    CD_PROP_INT32,
@@ -546,7 +560,8 @@ static ComponentAttributeProviders create_attribute_providers_for_curve()
                                                    curve_access,
                                                    make_array_read_attribute,
                                                    make_array_write_attribute,
-                                                   tag_component_topology_changed);
+                                                   tag_component_topology_changed,
+                                                   AttributeValidator{&resolution_clamp});
 
   static BuiltinCustomDataLayerProvider cyclic("cyclic",
                                                ATTR_DOMAIN_CURVE,
@@ -644,6 +659,7 @@ std::optional CurveComponent::attributes() cons
 
 std::optional CurveComponent::attributes_for_write()
 {
-  return blender::bke::MutableAttributeAccessor(curves_ ? &curves_->geometry : nullptr,
+  Curves *curves = this->get_for_write();
+  return blender::bke::MutableAttributeAccessor(curves ? &curves->geometry : nullptr,
                                                 blender::bke::get_curves_accessor_functions_ref());
 }
diff --git a/source/blender/blenkernel/intern/geometry_component_edit_data.cc b/source/blender/blenkernel/intern/geometry_component_edit_data.cc
new file mode 100644
index 00000000000..2c00de3254f
--- /dev/null
+++ b/source/blender/blenkernel/intern/geometry_component_edit_data.cc
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "BKE_curves.hh"
+#include "BKE_geometry_set.hh"
+
+using namespace blender;
+using namespace blender::bke;
+
+GeometryComponentEditData::GeometryComponentEditData() : GeometryComponent(GEO_COMPONENT_TYPE_EDIT)
+{
+}
+
+GeometryComponent *GeometryComponentEditData::copy() const
+{
+  GeometryComponentEditData *new_component = new GeometryComponentEditData();
+  if (curves_edit_hints_) {
+    new_component->curves_edit_hints_ = std::make_unique(*curves_edit_hints_);
+  }
+  return new_component;
+}
+
+bool GeometryComponentEditData::owns_direct_data() const
+{
+  return true;
+}
+
+void GeometryComponentEditData::ensure_owns_direct_data()
+{
+  /* Nothing to do. */
+}
+
+void GeometryComponentEditData::remember_deformed_curve_positions_if_necessary(
+    GeometrySet &geometry)
+{
+  /* This component should be created at the start of object evaluation if it's necessary. */
+  if (!geometry.has()) {
+    return;
+  }
+  GeometryComponentEditData &edit_component =
+      geometry.get_component_for_write();
+  if (!edit_component.curves_edit_hints_) {
+    return;
+  }
+  if (edit_component.curves_edit_hints_->positions.has_value()) {
+    return;
+  }
+  const Curves *curves_id = geometry.get_curves_for_read();
+  if (curves_id == nullptr) {
+    return;
+  }
+  const bke::CurvesGeometry &curves = bke::CurvesGeometry::wrap(curves_id->geometry);
+  const int points_num = curves.points_num();
+  if (points_num != edit_component.curves_edit_hints_->curves_id_orig.geometry.point_num) {
+    return;
+  }
+  edit_component.curves_edit_hints_->positions.emplace(points_num);
+  edit_component.curves_edit_hints_->positions->as_mutable_span().copy_from(curves.positions());
+}
diff --git a/source/blender/blenkernel/intern/geometry_component_instances.cc b/source/blender/blenkernel/intern/geometry_component_instances.cc
index c16311945ba..3a065c3576b 100644
--- a/source/blender/blenkernel/intern/geometry_component_instances.cc
+++ b/source/blender/blenkernel/intern/geometry_component_instances.cc
@@ -444,8 +444,7 @@ static ComponentAttributeProviders create_attribute_providers_for_instances()
       [](const void *owner) -> int {
         const InstancesComponent &inst = *static_cast(owner);
         return inst.instances_num();
-      },
-      nullptr};
+      }};
 
   /**
    * IDs of the instances. They are used for consistency over multiple frames for things like
diff --git a/source/blender/blenkernel/intern/geometry_component_mesh.cc b/source/blender/blenkernel/intern/geometry_component_mesh.cc
index cb36b9b19f7..255d0e92964 100644
--- a/source/blender/blenkernel/intern/geometry_component_mesh.cc
+++ b/source/blender/blenkernel/intern/geometry_component_mesh.cc
@@ -14,6 +14,8 @@
 #include "BKE_lib_id.h"
 #include "BKE_mesh.h"
 
+#include "FN_multi_function_builder.hh"
+
 #include "attribute_access_intern.hh"
 
 extern "C" MDeformVert *BKE_object_defgroup_data_create(ID *id);
@@ -115,8 +117,7 @@ void MeshComponent::ensure_owns_direct_data()
 
 namespace blender::bke {
 
-VArray mesh_normals_varray(const MeshComponent &mesh_component,
-                                   const Mesh &mesh,
+VArray mesh_normals_varray(const Mesh &mesh,
                                    const IndexMask mask,
                                    const eAttrDomain domain)
 {
@@ -135,8 +136,8 @@ VArray mesh_normals_varray(const MeshComponent &mesh_component,
        * instead of the GeometryComponent API to avoid calculating unnecessary values and to
        * allow normalizing the result more simply. */
       Span vert_normals{(float3 *)BKE_mesh_vertex_normals_ensure(&mesh), mesh.totvert};
+      const Span edges = mesh.edges();
       Array edge_normals(mask.min_array_size());
-      Span edges{mesh.medge, mesh.totedge};
       for (const int i : mask) {
         const MEdge &edge = edges[i];
         edge_normals[i] = math::normalize(
@@ -150,7 +151,7 @@ VArray mesh_normals_varray(const MeshComponent &mesh_component,
        * array and copy the face normal for each of its corners. In this case using the mesh
        * component's generic domain interpolation is fine, the data will still be normalized,
        * since the face normal is just copied to every corner. */
-      return mesh_component.attributes()->adapt_domain(
+      return mesh.attributes().adapt_domain(
           VArray::ForSpan({(float3 *)BKE_mesh_poly_normals_ensure(&mesh), mesh.totpoly}),
           ATTR_DOMAIN_FACE,
           ATTR_DOMAIN_CORNER);
@@ -176,11 +177,13 @@ static void adapt_mesh_domain_corner_to_point_impl(const Mesh &mesh,
                                                    MutableSpan r_values)
 {
   BLI_assert(r_values.size() == mesh.totvert);
+  const Span loops = mesh.loops();
+
   attribute_math::DefaultMixer mixer(r_values);
 
   for (const int loop_index : IndexRange(mesh.totloop)) {
     const T value = old_values[loop_index];
-    const MLoop &loop = mesh.mloop[loop_index];
+    const MLoop &loop = loops[loop_index];
     const int point_index = loop.v;
     mixer.mix_in(point_index, value);
   }
@@ -194,11 +197,13 @@ void adapt_mesh_domain_corner_to_point_impl(const Mesh &mesh,
                                             MutableSpan r_values)
 {
   BLI_assert(r_values.size() == mesh.totvert);
+  const Span loops = mesh.loops();
+
   Array loose_verts(mesh.totvert, true);
 
   r_values.fill(true);
   for (const int loop_index : IndexRange(mesh.totloop)) {
-    const MLoop &loop = mesh.mloop[loop_index];
+    const MLoop &loop = loops[loop_index];
     const int point_index = loop.v;
 
     loose_verts[point_index] = false;
@@ -236,12 +241,14 @@ static GVArray adapt_mesh_domain_corner_to_point(const Mesh &mesh, const GVArray
  */
 static GVArray adapt_mesh_domain_point_to_corner(const Mesh &mesh, const GVArray &varray)
 {
+  const Span loops = mesh.loops();
+
   GVArray new_varray;
   attribute_math::convert_to_static_type(varray.type(), [&](auto dummy) {
     using T = decltype(dummy);
     new_varray = VArray::ForFunc(mesh.totloop,
-                                    [&mesh, varray = varray.typed()](const int64_t loop_index) {
-                                      const int vertex_index = mesh.mloop[loop_index].v;
+                                    [loops, varray = varray.typed()](const int64_t loop_index) {
+                                      const int vertex_index = loops[loop_index].v;
                                       return varray[vertex_index];
                                     });
   });
@@ -250,15 +257,17 @@ static GVArray adapt_mesh_domain_point_to_corner(const Mesh &mesh, const GVArray
 
 static GVArray adapt_mesh_domain_corner_to_face(const Mesh &mesh, const GVArray &varray)
 {
+  const Span polys = mesh.polys();
+
   GVArray new_varray;
   attribute_math::convert_to_static_type(varray.type(), [&](auto dummy) {
     using T = decltype(dummy);
     if constexpr (!std::is_void_v>) {
       if constexpr (std::is_same_v) {
         new_varray = VArray::ForFunc(
-            mesh.totpoly, [&mesh, varray = varray.typed()](const int face_index) {
+            polys.size(), [polys, varray = varray.typed()](const int face_index) {
               /* A face is selected if all of its corners were selected. */
-              const MPoly &poly = mesh.mpoly[face_index];
+              const MPoly &poly = polys[face_index];
               for (const int loop_index : IndexRange(poly.loopstart, poly.totloop)) {
                 if (!varray[loop_index]) {
                   return false;
@@ -269,10 +278,10 @@ static GVArray adapt_mesh_domain_corner_to_face(const Mesh &mesh, const GVArray
       }
       else {
         new_varray = VArray::ForFunc(
-            mesh.totpoly, [&mesh, varray = varray.typed()](const int face_index) {
+            polys.size(), [polys, varray = varray.typed()](const int face_index) {
               T return_value;
               attribute_math::DefaultMixer mixer({&return_value, 1});
-              const MPoly &poly = mesh.mpoly[face_index];
+              const MPoly &poly = polys[face_index];
               for (const int loop_index : IndexRange(poly.loopstart, poly.totloop)) {
                 const T value = varray[loop_index];
                 mixer.mix_in(0, value);
@@ -292,18 +301,23 @@ static void adapt_mesh_domain_corner_to_edge_impl(const Mesh &mesh,
                                                   MutableSpan r_values)
 {
   BLI_assert(r_values.size() == mesh.totedge);
+  const Span polys = mesh.polys();
+  const Span loops = mesh.loops();
+
   attribute_math::DefaultMixer mixer(r_values);
 
-  for (const int poly_index : IndexRange(mesh.totpoly)) {
-    const MPoly &poly = mesh.mpoly[poly_index];
+  for (const int poly_index : polys.index_range()) {
+    const MPoly &poly = polys[poly_index];
 
     /* For every edge, mix values from the two adjacent corners (the current and next corner). */
-    for (const int loop_index : IndexRange(poly.loopstart, poly.totloop)) {
-      const int loop_index_next = (loop_index + 1) % poly.totloop;
-      const MLoop &loop = mesh.mloop[loop_index];
+    for (const int i : IndexRange(poly.totloop)) {
+      const int next_i = (i + 1) % poly.totloop;
+      const int loop_i = poly.loopstart + i;
+      const int next_loop_i = poly.loopstart + next_i;
+      const MLoop &loop = loops[loop_i];
       const int edge_index = loop.e;
-      mixer.mix_in(edge_index, old_values[loop_index]);
-      mixer.mix_in(edge_index, old_values[loop_index_next]);
+      mixer.mix_in(edge_index, old_values[loop_i]);
+      mixer.mix_in(edge_index, old_values[next_loop_i]);
     }
   }
 
@@ -317,21 +331,26 @@ void adapt_mesh_domain_corner_to_edge_impl(const Mesh &mesh,
                                            MutableSpan r_values)
 {
   BLI_assert(r_values.size() == mesh.totedge);
+  const Span polys = mesh.polys();
+  const Span loops = mesh.loops();
 
   /* It may be possible to rely on the #ME_LOOSEEDGE flag, but that seems error-prone. */
   Array loose_edges(mesh.totedge, true);
 
   r_values.fill(true);
-  for (const int poly_index : IndexRange(mesh.totpoly)) {
-    const MPoly &poly = mesh.mpoly[poly_index];
-
-    for (const int loop_index : IndexRange(poly.loopstart, poly.totloop)) {
-      const int loop_index_next = (loop_index == poly.totloop) ? poly.loopstart : (loop_index + 1);
-      const MLoop &loop = mesh.mloop[loop_index];
+  for (const int poly_index : polys.index_range()) {
+    const MPoly &poly = polys[poly_index];
+
+    for (const int i : IndexRange(poly.totloop)) {
+      const int next_i = (i + 1) % poly.totloop;
+      const int loop_i = poly.loopstart + i;
+      const int next_loop_i = poly.loopstart + next_i;
+      const MLoop &loop = loops[loop_i];
       const int edge_index = loop.e;
+
       loose_edges[edge_index] = false;
 
-      if (!old_values[loop_index] || !old_values[loop_index_next]) {
+      if (!old_values[loop_i] || !old_values[next_loop_i]) {
         r_values[edge_index] = false;
       }
     }
@@ -367,13 +386,16 @@ void adapt_mesh_domain_face_to_point_impl(const Mesh &mesh,
                                           MutableSpan r_values)
 {
   BLI_assert(r_values.size() == mesh.totvert);
+  const Span polys = mesh.polys();
+  const Span loops = mesh.loops();
+
   attribute_math::DefaultMixer mixer(r_values);
 
-  for (const int poly_index : IndexRange(mesh.totpoly)) {
-    const MPoly &poly = mesh.mpoly[poly_index];
+  for (const int poly_index : polys.index_range()) {
+    const MPoly &poly = polys[poly_index];
     const T value = old_values[poly_index];
     for (const int loop_index : IndexRange(poly.loopstart, poly.totloop)) {
-      const MLoop &loop = mesh.mloop[loop_index];
+      const MLoop &loop = loops[loop_index];
       const int point_index = loop.v;
       mixer.mix_in(point_index, value);
     }
@@ -389,13 +411,15 @@ void adapt_mesh_domain_face_to_point_impl(const Mesh &mesh,
                                           MutableSpan r_values)
 {
   BLI_assert(r_values.size() == mesh.totvert);
+  const Span polys = mesh.polys();
+  const Span loops = mesh.loops();
 
   r_values.fill(false);
-  for (const int poly_index : IndexRange(mesh.totpoly)) {
-    const MPoly &poly = mesh.mpoly[poly_index];
+  for (const int poly_index : polys.index_range()) {
+    const MPoly &poly = polys[poly_index];
     if (old_values[poly_index]) {
       for (const int loop_index : IndexRange(poly.loopstart, poly.totloop)) {
-        const MLoop &loop = mesh.mloop[loop_index];
+        const MLoop &loop = loops[loop_index];
         const int vert_index = loop.v;
         r_values[vert_index] = true;
       }
@@ -424,10 +448,11 @@ void adapt_mesh_domain_face_to_corner_impl(const Mesh &mesh,
                                            MutableSpan r_values)
 {
   BLI_assert(r_values.size() == mesh.totloop);
+  const Span polys = mesh.polys();
 
-  threading::parallel_for(IndexRange(mesh.totpoly), 1024, [&](const IndexRange range) {
+  threading::parallel_for(polys.index_range(), 1024, [&](const IndexRange range) {
     for (const int poly_index : range) {
-      const MPoly &poly = mesh.mpoly[poly_index];
+      const MPoly &poly = polys[poly_index];
       MutableSpan poly_corner_values = r_values.slice(poly.loopstart, poly.totloop);
       poly_corner_values.fill(old_values[poly_index]);
     }
@@ -454,13 +479,16 @@ void adapt_mesh_domain_face_to_edge_impl(const Mesh &mesh,
                                          MutableSpan r_values)
 {
   BLI_assert(r_values.size() == mesh.totedge);
+  const Span polys = mesh.polys();
+  const Span loops = mesh.loops();
+
   attribute_math::DefaultMixer mixer(r_values);
 
-  for (const int poly_index : IndexRange(mesh.totpoly)) {
-    const MPoly &poly = mesh.mpoly[poly_index];
+  for (const int poly_index : polys.index_range()) {
+    const MPoly &poly = polys[poly_index];
     const T value = old_values[poly_index];
     for (const int loop_index : IndexRange(poly.loopstart, poly.totloop)) {
-      const MLoop &loop = mesh.mloop[loop_index];
+      const MLoop &loop = loops[loop_index];
       mixer.mix_in(loop.e, value);
     }
   }
@@ -474,13 +502,15 @@ void adapt_mesh_domain_face_to_edge_impl(const Mesh &mesh,
                                          MutableSpan r_values)
 {
   BLI_assert(r_values.size() == mesh.totedge);
+  const Span polys = mesh.polys();
+  const Span loops = mesh.loops();
 
   r_values.fill(false);
-  for (const int poly_index : IndexRange(mesh.totpoly)) {
-    const MPoly &poly = mesh.mpoly[poly_index];
+  for (const int poly_index : polys.index_range()) {
+    const MPoly &poly = polys[poly_index];
     if (old_values[poly_index]) {
       for (const int loop_index : IndexRange(poly.loopstart, poly.totloop)) {
-        const MLoop &loop = mesh.mloop[loop_index];
+        const MLoop &loop = loops[loop_index];
         const int edge_index = loop.e;
         r_values[edge_index] = true;
       }
@@ -504,17 +534,20 @@ static GVArray adapt_mesh_domain_face_to_edge(const Mesh &mesh, const GVArray &v
 
 static GVArray adapt_mesh_domain_point_to_face(const Mesh &mesh, const GVArray &varray)
 {
+  const Span polys = mesh.polys();
+  const Span loops = mesh.loops();
+
   GVArray new_varray;
   attribute_math::convert_to_static_type(varray.type(), [&](auto dummy) {
     using T = decltype(dummy);
     if constexpr (!std::is_void_v>) {
       if constexpr (std::is_same_v) {
         new_varray = VArray::ForFunc(
-            mesh.totpoly, [&mesh, varray = varray.typed()](const int face_index) {
+            mesh.totpoly, [loops, polys, varray = varray.typed()](const int face_index) {
               /* A face is selected if all of its vertices were selected. */
-              const MPoly &poly = mesh.mpoly[face_index];
+              const MPoly &poly = polys[face_index];
               for (const int loop_index : IndexRange(poly.loopstart, poly.totloop)) {
-                const MLoop &loop = mesh.mloop[loop_index];
+                const MLoop &loop = loops[loop_index];
                 if (!varray[loop.v]) {
                   return false;
                 }
@@ -524,12 +557,12 @@ static GVArray adapt_mesh_domain_point_to_face(const Mesh &mesh, const GVArray &
       }
       else {
         new_varray = VArray::ForFunc(
-            mesh.totpoly, [&mesh, varray = varray.typed()](const int face_index) {
+            mesh.totpoly, [loops, polys, varray = varray.typed()](const int face_index) {
               T return_value;
               attribute_math::DefaultMixer mixer({&return_value, 1});
-              const MPoly &poly = mesh.mpoly[face_index];
+              const MPoly &poly = polys[face_index];
               for (const int loop_index : IndexRange(poly.loopstart, poly.totloop)) {
-                const MLoop &loop = mesh.mloop[loop_index];
+                const MLoop &loop = loops[loop_index];
                 const T value = varray[loop.v];
                 mixer.mix_in(0, value);
               }
@@ -544,6 +577,8 @@ static GVArray adapt_mesh_domain_point_to_face(const Mesh &mesh, const GVArray &
 
 static GVArray adapt_mesh_domain_point_to_edge(const Mesh &mesh, const GVArray &varray)
 {
+  const Span edges = mesh.edges();
+
   GVArray new_varray;
   attribute_math::convert_to_static_type(varray.type(), [&](auto dummy) {
     using T = decltype(dummy);
@@ -551,17 +586,17 @@ static GVArray adapt_mesh_domain_point_to_edge(const Mesh &mesh, const GVArray &
       if constexpr (std::is_same_v) {
         /* An edge is selected if both of its vertices were selected. */
         new_varray = VArray::ForFunc(
-            mesh.totedge, [&mesh, varray = varray.typed()](const int edge_index) {
-              const MEdge &edge = mesh.medge[edge_index];
+            edges.size(), [edges, varray = varray.typed()](const int edge_index) {
+              const MEdge &edge = edges[edge_index];
               return varray[edge.v1] && varray[edge.v2];
             });
       }
       else {
         new_varray = VArray::ForFunc(
-            mesh.totedge, [&mesh, varray = varray.typed()](const int edge_index) {
+            edges.size(), [edges, varray = varray.typed()](const int edge_index) {
               T return_value;
               attribute_math::DefaultMixer mixer({&return_value, 1});
-              const MEdge &edge = mesh.medge[edge_index];
+              const MEdge &edge = edges[edge_index];
               mixer.mix_in(0, varray[edge.v1]);
               mixer.mix_in(0, varray[edge.v2]);
               mixer.finalize();
@@ -579,16 +614,19 @@ void adapt_mesh_domain_edge_to_corner_impl(const Mesh &mesh,
                                            MutableSpan r_values)
 {
   BLI_assert(r_values.size() == mesh.totloop);
+  const Span polys = mesh.polys();
+  const Span loops = mesh.loops();
+
   attribute_math::DefaultMixer mixer(r_values);
 
-  for (const int poly_index : IndexRange(mesh.totpoly)) {
-    const MPoly &poly = mesh.mpoly[poly_index];
+  for (const int poly_index : polys.index_range()) {
+    const MPoly &poly = polys[poly_index];
 
     /* For every corner, mix the values from the adjacent edges on the face. */
     for (const int loop_index : IndexRange(poly.loopstart, poly.totloop)) {
       const int loop_index_prev = loop_index - 1 + (loop_index == poly.loopstart) * poly.totloop;
-      const MLoop &loop = mesh.mloop[loop_index];
-      const MLoop &loop_prev = mesh.mloop[loop_index_prev];
+      const MLoop &loop = loops[loop_index];
+      const MLoop &loop_prev = loops[loop_index_prev];
       mixer.mix_in(loop_index, old_values[loop.e]);
       mixer.mix_in(loop_index, old_values[loop_prev.e]);
     }
@@ -604,15 +642,17 @@ void adapt_mesh_domain_edge_to_corner_impl(const Mesh &mesh,
                                            MutableSpan r_values)
 {
   BLI_assert(r_values.size() == mesh.totloop);
+  const Span polys = mesh.polys();
+  const Span loops = mesh.loops();
 
   r_values.fill(false);
 
-  for (const int poly_index : IndexRange(mesh.totpoly)) {
-    const MPoly &poly = mesh.mpoly[poly_index];
+  for (const int poly_index : polys.index_range()) {
+    const MPoly &poly = polys[poly_index];
     for (const int loop_index : IndexRange(poly.loopstart, poly.totloop)) {
       const int loop_index_prev = loop_index - 1 + (loop_index == poly.loopstart) * poly.totloop;
-      const MLoop &loop = mesh.mloop[loop_index];
-      const MLoop &loop_prev = mesh.mloop[loop_index_prev];
+      const MLoop &loop = loops[loop_index];
+      const MLoop &loop_prev = loops[loop_index_prev];
       if (old_values[loop.e] && old_values[loop_prev.e]) {
         r_values[loop_index] = true;
       }
@@ -640,10 +680,12 @@ static void adapt_mesh_domain_edge_to_point_impl(const Mesh &mesh,
                                                  MutableSpan r_values)
 {
   BLI_assert(r_values.size() == mesh.totvert);
+  const Span edges = mesh.edges();
+
   attribute_math::DefaultMixer mixer(r_values);
 
   for (const int edge_index : IndexRange(mesh.totedge)) {
-    const MEdge &edge = mesh.medge[edge_index];
+    const MEdge &edge = edges[edge_index];
     const T value = old_values[edge_index];
     mixer.mix_in(edge.v1, value);
     mixer.mix_in(edge.v2, value);
@@ -659,10 +701,11 @@ void adapt_mesh_domain_edge_to_point_impl(const Mesh &mesh,
                                           MutableSpan r_values)
 {
   BLI_assert(r_values.size() == mesh.totvert);
+  const Span edges = mesh.edges();
 
   r_values.fill(false);
-  for (const int edge_index : IndexRange(mesh.totedge)) {
-    const MEdge &edge = mesh.medge[edge_index];
+  for (const int edge_index : edges.index_range()) {
+    const MEdge &edge = edges[edge_index];
     if (old_values[edge_index]) {
       r_values[edge.v1] = true;
       r_values[edge.v2] = true;
@@ -686,6 +729,9 @@ static GVArray adapt_mesh_domain_edge_to_point(const Mesh &mesh, const GVArray &
 
 static GVArray adapt_mesh_domain_edge_to_face(const Mesh &mesh, const GVArray &varray)
 {
+  const Span polys = mesh.polys();
+  const Span loops = mesh.loops();
+
   GVArray new_varray;
   attribute_math::convert_to_static_type(varray.type(), [&](auto dummy) {
     using T = decltype(dummy);
@@ -693,10 +739,10 @@ static GVArray adapt_mesh_domain_edge_to_face(const Mesh &mesh, const GVArray &v
       if constexpr (std::is_same_v) {
         /* A face is selected if all of its edges are selected. */
         new_varray = VArray::ForFunc(
-            mesh.totpoly, [&mesh, varray = varray.typed()](const int face_index) {
-              const MPoly &poly = mesh.mpoly[face_index];
+            polys.size(), [loops, polys, varray = varray.typed()](const int face_index) {
+              const MPoly &poly = polys[face_index];
               for (const int loop_index : IndexRange(poly.loopstart, poly.totloop)) {
-                const MLoop &loop = mesh.mloop[loop_index];
+                const MLoop &loop = loops[loop_index];
                 if (!varray[loop.e]) {
                   return false;
                 }
@@ -706,12 +752,12 @@ static GVArray adapt_mesh_domain_edge_to_face(const Mesh &mesh, const GVArray &v
       }
       else {
         new_varray = VArray::ForFunc(
-            mesh.totpoly, [&mesh, varray = varray.typed()](const int face_index) {
+            polys.size(), [loops, polys, varray = varray.typed()](const int face_index) {
               T return_value;
               attribute_math::DefaultMixer mixer({&return_value, 1});
-              const MPoly &poly = mesh.mpoly[face_index];
+              const MPoly &poly = polys[face_index];
               for (const int loop_index : IndexRange(poly.loopstart, poly.totloop)) {
-                const MLoop &loop = mesh.mloop[loop_index];
+                const MLoop &loop = loops[loop_index];
                 const T value = varray[loop.e];
                 mixer.mix_in(0, value);
               }
@@ -838,16 +884,6 @@ static void tag_component_positions_changed(void *owner)
   }
 }
 
-static int get_material_index(const MPoly &mpoly)
-{
-  return static_cast(mpoly.mat_nr);
-}
-
-static void set_material_index(MPoly &mpoly, int index)
-{
-  mpoly.mat_nr = static_cast(std::clamp(index, 0, SHRT_MAX));
-}
-
 static bool get_shade_smooth(const MPoly &mpoly)
 {
   return mpoly.flag & ME_SMOOTH;
@@ -884,8 +920,15 @@ class VArrayImpl_For_VertexWeights final : public VMutableArrayImpl {
   const int dvert_index_;
 
  public:
-  VArrayImpl_For_VertexWeights(MDeformVert *dverts, const int totvert, const int dvert_index)
-      : VMutableArrayImpl(totvert), dverts_(dverts), dvert_index_(dvert_index)
+  VArrayImpl_For_VertexWeights(MutableSpan dverts, const int dvert_index)
+      : VMutableArrayImpl(dverts.size()), dverts_(dverts.data()), dvert_index_(dvert_index)
+  {
+  }
+
+  VArrayImpl_For_VertexWeights(Span dverts, const int dvert_index)
+      : VMutableArrayImpl(dverts.size()),
+        dverts_(const_cast(dverts.data())),
+        dvert_index_(dvert_index)
   {
   }
 
@@ -983,12 +1026,12 @@ class VertexGroupsAttributeProvider final : public DynamicAttributesProvider {
     if (vertex_group_index < 0) {
       return {};
     }
-    if (mesh->dvert == nullptr) {
+    const Span dverts = mesh->deform_verts();
+    if (dverts.is_empty()) {
       static const float default_value = 0.0f;
       return {VArray::ForSingle(default_value, mesh->totvert), ATTR_DOMAIN_POINT};
     }
-    return {VArray::For(
-                mesh->dvert, mesh->totvert, vertex_group_index),
+    return {VArray::For(dverts, vertex_group_index),
             ATTR_DOMAIN_POINT};
   }
 
@@ -1008,16 +1051,8 @@ class VertexGroupsAttributeProvider final : public DynamicAttributesProvider {
     if (vertex_group_index < 0) {
       return {};
     }
-    if (mesh->dvert == nullptr) {
-      BKE_object_defgroup_data_create(&mesh->id);
-    }
-    else {
-      /* Copy the data layer if it is shared with some other mesh. */
-      mesh->dvert = (MDeformVert *)CustomData_duplicate_referenced_layer(
-          &mesh->vdata, CD_MDEFORMVERT, mesh->totvert);
-    }
-    return {VMutableArray::For(
-                mesh->dvert, mesh->totvert, vertex_group_index),
+    MutableSpan dverts = mesh->deform_verts_for_write();
+    return {VMutableArray::For(dverts, vertex_group_index),
             ATTR_DOMAIN_POINT};
   }
 
@@ -1040,15 +1075,11 @@ class VertexGroupsAttributeProvider final : public DynamicAttributesProvider {
     }
     BLI_remlink(&mesh->vertex_group_names, group);
     MEM_freeN(group);
-    if (mesh->dvert == nullptr) {
+    if (mesh->deform_verts().is_empty()) {
       return true;
     }
 
-    /* Copy the data layer if it is shared with some other mesh. */
-    mesh->dvert = (MDeformVert *)CustomData_duplicate_referenced_layer(
-        &mesh->vdata, CD_MDEFORMVERT, mesh->totvert);
-
-    for (MDeformVert &dvert : MutableSpan(mesh->dvert, mesh->totvert)) {
+    for (MDeformVert &dvert : mesh->deform_verts_for_write()) {
       MDeformWeight *weight = BKE_defvert_find_index(&dvert, index);
       BKE_defvert_remove_group(&dvert, weight);
       for (MDeformWeight &weight : MutableSpan(dvert.dw, dvert.totweight)) {
@@ -1129,11 +1160,6 @@ class NormalAttributeProvider final : public BuiltinAttributeProvider {
  */
 static ComponentAttributeProviders create_attribute_providers_for_mesh()
 {
-  static auto update_custom_data_pointers = [](void *owner) {
-    Mesh *mesh = static_cast(owner);
-    BKE_mesh_update_customdata_pointers(mesh, false);
-  };
-
 #define MAKE_MUTABLE_CUSTOM_DATA_GETTER(NAME) \
   [](void *owner) -> CustomData * { \
     Mesh *mesh = static_cast(owner); \
@@ -1152,20 +1178,16 @@ static ComponentAttributeProviders create_attribute_providers_for_mesh()
 
   static CustomDataAccessInfo corner_access = {MAKE_MUTABLE_CUSTOM_DATA_GETTER(ldata),
                                                MAKE_CONST_CUSTOM_DATA_GETTER(ldata),
-                                               MAKE_GET_ELEMENT_NUM_GETTER(totloop),
-                                               update_custom_data_pointers};
+                                               MAKE_GET_ELEMENT_NUM_GETTER(totloop)};
   static CustomDataAccessInfo point_access = {MAKE_MUTABLE_CUSTOM_DATA_GETTER(vdata),
                                               MAKE_CONST_CUSTOM_DATA_GETTER(vdata),
-                                              MAKE_GET_ELEMENT_NUM_GETTER(totvert),
-                                              update_custom_data_pointers};
+                                              MAKE_GET_ELEMENT_NUM_GETTER(totvert)};
   static CustomDataAccessInfo edge_access = {MAKE_MUTABLE_CUSTOM_DATA_GETTER(edata),
                                              MAKE_CONST_CUSTOM_DATA_GETTER(edata),
-                                             MAKE_GET_ELEMENT_NUM_GETTER(totedge),
-                                             update_custom_data_pointers};
+                                             MAKE_GET_ELEMENT_NUM_GETTER(totedge)};
   static CustomDataAccessInfo face_access = {MAKE_MUTABLE_CUSTOM_DATA_GETTER(pdata),
                                              MAKE_CONST_CUSTOM_DATA_GETTER(pdata),
-                                             MAKE_GET_ELEMENT_NUM_GETTER(totpoly),
-                                             update_custom_data_pointers};
+                                             MAKE_GET_ELEMENT_NUM_GETTER(totpoly)};
 
 #undef MAKE_CONST_CUSTOM_DATA_GETTER
 #undef MAKE_MUTABLE_CUSTOM_DATA_GETTER
@@ -1197,18 +1219,25 @@ static ComponentAttributeProviders create_attribute_providers_for_mesh()
                                            make_array_write_attribute,
                                            nullptr);
 
-  static BuiltinCustomDataLayerProvider material_index(
-      "material_index",
-      ATTR_DOMAIN_FACE,
-      CD_PROP_INT32,
-      CD_MPOLY,
-      BuiltinAttributeProvider::NonCreatable,
-      BuiltinAttributeProvider::Writable,
-      BuiltinAttributeProvider::NonDeletable,
-      face_access,
-      make_derived_read_attribute,
-      make_derived_write_attribute,
-      nullptr);
+  static const fn::CustomMF_SI_SO material_index_clamp{
+      "Material Index Validate",
+      [](int value) {
+        /* Use #short for the maximum since many areas still use that type for indices. */
+        return std::clamp(value, 0, std::numeric_limits::max());
+      },
+      fn::CustomMF_presets::AllSpanOrSingle()};
+  static BuiltinCustomDataLayerProvider material_index("material_index",
+                                                       ATTR_DOMAIN_FACE,
+                                                       CD_PROP_INT32,
+                                                       CD_PROP_INT32,
+                                                       BuiltinAttributeProvider::Creatable,
+                                                       BuiltinAttributeProvider::Writable,
+                                                       BuiltinAttributeProvider::Deletable,
+                                                       face_access,
+                                                       make_array_read_attribute,
+                                                       make_array_write_attribute,
+                                                       nullptr,
+                                                       AttributeValidator{&material_index_clamp});
 
   static BuiltinCustomDataLayerProvider shade_smooth(
       "shade_smooth",
@@ -1305,18 +1334,19 @@ static const AttributeAccessorFunctions &get_mesh_accessor_functions_ref()
   return fn;
 }
 
-AttributeAccessor mesh_attributes(const Mesh &mesh)
+}  // namespace blender::bke
+
+blender::bke::AttributeAccessor Mesh::attributes() const
 {
-  return AttributeAccessor(&mesh, get_mesh_accessor_functions_ref());
+  return blender::bke::AttributeAccessor(this, blender::bke::get_mesh_accessor_functions_ref());
 }
 
-MutableAttributeAccessor mesh_attributes_for_write(Mesh &mesh)
+blender::bke::MutableAttributeAccessor Mesh::attributes_for_write()
 {
-  return MutableAttributeAccessor(&mesh, get_mesh_accessor_functions_ref());
+  return blender::bke::MutableAttributeAccessor(this,
+                                                blender::bke::get_mesh_accessor_functions_ref());
 }
 
-}  // namespace blender::bke
-
 std::optional MeshComponent::attributes() const
 {
   return blender::bke::AttributeAccessor(mesh_, blender::bke::get_mesh_accessor_functions_ref());
@@ -1324,7 +1354,8 @@ std::optional MeshComponent::attributes() const
 
 std::optional MeshComponent::attributes_for_write()
 {
-  return blender::bke::MutableAttributeAccessor(mesh_,
+  Mesh *mesh = this->get_for_write();
+  return blender::bke::MutableAttributeAccessor(mesh,
                                                 blender::bke::get_mesh_accessor_functions_ref());
 }
 
diff --git a/source/blender/blenkernel/intern/geometry_component_pointcloud.cc b/source/blender/blenkernel/intern/geometry_component_pointcloud.cc
index b439a9ba7f8..6980b561bc3 100644
--- a/source/blender/blenkernel/intern/geometry_component_pointcloud.cc
+++ b/source/blender/blenkernel/intern/geometry_component_pointcloud.cc
@@ -111,10 +111,6 @@ namespace blender::bke {
  */
 static ComponentAttributeProviders create_attribute_providers_for_point_cloud()
 {
-  static auto update_custom_data_pointers = [](void *owner) {
-    PointCloud *pointcloud = static_cast(owner);
-    BKE_pointcloud_update_customdata_pointers(pointcloud);
-  };
   static CustomDataAccessInfo point_access = {
       [](void *owner) -> CustomData * {
         PointCloud *pointcloud = static_cast(owner);
@@ -127,8 +123,7 @@ static ComponentAttributeProviders create_attribute_providers_for_point_cloud()
       [](const void *owner) -> int {
         const PointCloud *pointcloud = static_cast(owner);
         return pointcloud->totpoint;
-      },
-      update_custom_data_pointers};
+      }};
 
   static BuiltinCustomDataLayerProvider position("position",
                                                  ATTR_DOMAIN_POINT,
@@ -206,18 +201,20 @@ static const AttributeAccessorFunctions &get_pointcloud_accessor_functions_ref()
   return fn;
 }
 
-AttributeAccessor pointcloud_attributes(const PointCloud &pointcloud)
+}  // namespace blender::bke
+
+blender::bke::AttributeAccessor PointCloud::attributes() const
 {
-  return AttributeAccessor(&pointcloud, get_pointcloud_accessor_functions_ref());
+  return blender::bke::AttributeAccessor(this,
+                                         blender::bke::get_pointcloud_accessor_functions_ref());
 }
 
-MutableAttributeAccessor pointcloud_attributes_for_write(PointCloud &pointcloud)
+blender::bke::MutableAttributeAccessor PointCloud::attributes_for_write()
 {
-  return MutableAttributeAccessor(&pointcloud, get_pointcloud_accessor_functions_ref());
+  return blender::bke::MutableAttributeAccessor(
+      this, blender::bke::get_pointcloud_accessor_functions_ref());
 }
 
-}  // namespace blender::bke
-
 std::optional PointCloudComponent::attributes() const
 {
   return blender::bke::AttributeAccessor(pointcloud_,
@@ -226,8 +223,9 @@ std::optional PointCloudComponent::attributes()
 
 std::optional PointCloudComponent::attributes_for_write()
 {
+  PointCloud *pointcloud = this->get_for_write();
   return blender::bke::MutableAttributeAccessor(
-      pointcloud_, blender::bke::get_pointcloud_accessor_functions_ref());
+      pointcloud, blender::bke::get_pointcloud_accessor_functions_ref());
 }
 
 /** \} */
diff --git a/source/blender/blenkernel/intern/geometry_fields.cc b/source/blender/blenkernel/intern/geometry_fields.cc
new file mode 100644
index 00000000000..56e9e9dcdff
--- /dev/null
+++ b/source/blender/blenkernel/intern/geometry_fields.cc
@@ -0,0 +1,365 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "BKE_attribute.hh"
+#include "BKE_curves.hh"
+#include "BKE_geometry_fields.hh"
+#include "BKE_geometry_set.hh"
+#include "BKE_mesh.h"
+#include "BKE_pointcloud.h"
+#include "BKE_type_conversions.hh"
+
+#include "DNA_mesh_types.h"
+#include "DNA_pointcloud_types.h"
+
+#include "BLT_translation.h"
+
+namespace blender::bke {
+
+MeshFieldContext::MeshFieldContext(const Mesh &mesh, const eAttrDomain domain)
+    : mesh_(mesh), domain_(domain)
+{
+  BLI_assert(mesh.attributes().domain_supported(domain_));
+}
+
+CurvesFieldContext::CurvesFieldContext(const CurvesGeometry &curves, const eAttrDomain domain)
+    : curves_(curves), domain_(domain)
+{
+  BLI_assert(curves.attributes().domain_supported(domain));
+}
+
+GeometryFieldContext::GeometryFieldContext(const void *geometry,
+                                           const GeometryComponentType type,
+                                           const eAttrDomain domain)
+    : geometry_(geometry), type_(type), domain_(domain)
+{
+  BLI_assert(ELEM(type,
+                  GEO_COMPONENT_TYPE_MESH,
+                  GEO_COMPONENT_TYPE_CURVE,
+                  GEO_COMPONENT_TYPE_POINT_CLOUD,
+                  GEO_COMPONENT_TYPE_INSTANCES));
+}
+
+GeometryFieldContext::GeometryFieldContext(const GeometryComponent &component,
+                                           const eAttrDomain domain)
+    : type_(component.type()), domain_(domain)
+{
+  switch (component.type()) {
+    case GEO_COMPONENT_TYPE_MESH: {
+      const MeshComponent &mesh_component = static_cast(component);
+      geometry_ = mesh_component.get_for_read();
+      break;
+    }
+    case GEO_COMPONENT_TYPE_CURVE: {
+      const CurveComponent &curve_component = static_cast(component);
+      const Curves *curves = curve_component.get_for_read();
+      geometry_ = curves ? &CurvesGeometry::wrap(curves->geometry) : nullptr;
+      break;
+    }
+    case GEO_COMPONENT_TYPE_POINT_CLOUD: {
+      const PointCloudComponent &pointcloud_component = static_cast(
+          component);
+      geometry_ = pointcloud_component.get_for_read();
+      break;
+    }
+    case GEO_COMPONENT_TYPE_INSTANCES: {
+      const InstancesComponent &instances_component = static_cast(
+          component);
+      geometry_ = &instances_component;
+      break;
+    }
+    case GEO_COMPONENT_TYPE_VOLUME:
+    case GEO_COMPONENT_TYPE_EDIT:
+      BLI_assert_unreachable();
+      break;
+  }
+}
+
+GeometryFieldContext::GeometryFieldContext(const Mesh &mesh, eAttrDomain domain)
+    : geometry_(&mesh), type_(GEO_COMPONENT_TYPE_MESH), domain_(domain)
+{
+}
+GeometryFieldContext::GeometryFieldContext(const CurvesGeometry &curves, eAttrDomain domain)
+    : geometry_(&curves), type_(GEO_COMPONENT_TYPE_CURVE), domain_(domain)
+{
+}
+GeometryFieldContext::GeometryFieldContext(const PointCloud &points)
+    : geometry_(&points), type_(GEO_COMPONENT_TYPE_POINT_CLOUD), domain_(ATTR_DOMAIN_POINT)
+{
+}
+GeometryFieldContext::GeometryFieldContext(const InstancesComponent &instances)
+    : geometry_(&instances), type_(GEO_COMPONENT_TYPE_INSTANCES), domain_(ATTR_DOMAIN_INSTANCE)
+{
+}
+
+std::optional GeometryFieldContext::attributes() const
+{
+  if (const Mesh *mesh = this->mesh()) {
+    return mesh->attributes();
+  }
+  if (const CurvesGeometry *curves = this->curves()) {
+    return curves->attributes();
+  }
+  if (const PointCloud *pointcloud = this->pointcloud()) {
+    return pointcloud->attributes();
+  }
+  if (const InstancesComponent *instances = this->instances()) {
+    return instances->attributes();
+  }
+  return {};
+}
+
+const Mesh *GeometryFieldContext::mesh() const
+{
+  return this->type() == GEO_COMPONENT_TYPE_MESH ? static_cast(geometry_) : nullptr;
+}
+const CurvesGeometry *GeometryFieldContext::curves() const
+{
+  return this->type() == GEO_COMPONENT_TYPE_CURVE ?
+             static_cast(geometry_) :
+             nullptr;
+}
+const PointCloud *GeometryFieldContext::pointcloud() const
+{
+  return this->type() == GEO_COMPONENT_TYPE_POINT_CLOUD ?
+             static_cast(geometry_) :
+             nullptr;
+}
+const InstancesComponent *GeometryFieldContext::instances() const
+{
+  return this->type() == GEO_COMPONENT_TYPE_INSTANCES ?
+             static_cast(geometry_) :
+             nullptr;
+}
+
+GVArray GeometryFieldInput::get_varray_for_context(const fn::FieldContext &context,
+                                                   const IndexMask mask,
+                                                   ResourceScope & /*scope*/) const
+{
+  if (const GeometryFieldContext *geometry_context = dynamic_cast(
+          &context)) {
+    return this->get_varray_for_context(*geometry_context, mask);
+  }
+  if (const MeshFieldContext *mesh_context = dynamic_cast(&context)) {
+    return this->get_varray_for_context({mesh_context->mesh(), mesh_context->domain()}, mask);
+  }
+  if (const CurvesFieldContext *curve_context = dynamic_cast(
+          &context)) {
+    return this->get_varray_for_context({curve_context->curves(), curve_context->domain()}, mask);
+  }
+  if (const PointCloudFieldContext *point_context = dynamic_cast(
+          &context)) {
+    return this->get_varray_for_context({point_context->pointcloud()}, mask);
+  }
+  if (const InstancesFieldContext *instances_context = dynamic_cast(
+          &context)) {
+    return this->get_varray_for_context({instances_context->instances()}, mask);
+  }
+  return {};
+}
+
+GVArray MeshFieldInput::get_varray_for_context(const fn::FieldContext &context,
+                                               const IndexMask mask,
+                                               ResourceScope & /*scope*/) const
+{
+  if (const GeometryFieldContext *geometry_context = dynamic_cast(
+          &context)) {
+    if (const Mesh *mesh = geometry_context->mesh()) {
+      return this->get_varray_for_context(*mesh, geometry_context->domain(), mask);
+    }
+  }
+  if (const MeshFieldContext *mesh_context = dynamic_cast(&context)) {
+    return this->get_varray_for_context(mesh_context->mesh(), mesh_context->domain(), mask);
+  }
+  return {};
+}
+
+GVArray CurvesFieldInput::get_varray_for_context(const fn::FieldContext &context,
+                                                 IndexMask mask,
+                                                 ResourceScope & /*scope*/) const
+{
+  if (const GeometryFieldContext *geometry_context = dynamic_cast(
+          &context)) {
+    if (const CurvesGeometry *curves = geometry_context->curves()) {
+      return this->get_varray_for_context(*curves, geometry_context->domain(), mask);
+    }
+  }
+  if (const CurvesFieldContext *curves_context = dynamic_cast(
+          &context)) {
+    return this->get_varray_for_context(curves_context->curves(), curves_context->domain(), mask);
+  }
+  return {};
+}
+
+GVArray PointCloudFieldInput::get_varray_for_context(const fn::FieldContext &context,
+                                                     IndexMask mask,
+                                                     ResourceScope & /*scope*/) const
+{
+  if (const GeometryFieldContext *geometry_context = dynamic_cast(
+          &context)) {
+    if (const PointCloud *pointcloud = geometry_context->pointcloud()) {
+      return this->get_varray_for_context(*pointcloud, mask);
+    }
+  }
+  if (const PointCloudFieldContext *point_context = dynamic_cast(
+          &context)) {
+    return this->get_varray_for_context(point_context->pointcloud(), mask);
+  }
+  return {};
+}
+
+GVArray InstancesFieldInput::get_varray_for_context(const fn::FieldContext &context,
+                                                    IndexMask mask,
+                                                    ResourceScope & /*scope*/) const
+{
+  if (const GeometryFieldContext *geometry_context = dynamic_cast(
+          &context)) {
+    if (const InstancesComponent *instances = geometry_context->instances()) {
+      return this->get_varray_for_context(*instances, mask);
+    }
+  }
+  if (const InstancesFieldContext *instances_context = dynamic_cast(
+          &context)) {
+    return this->get_varray_for_context(instances_context->instances(), mask);
+  }
+  return {};
+}
+
+GVArray AttributeFieldInput::get_varray_for_context(const GeometryFieldContext &context,
+                                                    IndexMask UNUSED(mask)) const
+{
+  const eCustomDataType data_type = cpp_type_to_custom_data_type(*type_);
+  if (auto attributes = context.attributes()) {
+    return attributes->lookup(name_, context.domain(), data_type);
+  }
+  return {};
+}
+
+std::string AttributeFieldInput::socket_inspection_name() const
+{
+  std::stringstream ss;
+  ss << '"' << name_ << '"' << TIP_(" attribute from geometry");
+  return ss.str();
+}
+
+uint64_t AttributeFieldInput::hash() const
+{
+  return get_default_hash_2(name_, type_);
+}
+
+bool AttributeFieldInput::is_equal_to(const fn::FieldNode &other) const
+{
+  if (const AttributeFieldInput *other_typed = dynamic_cast(&other)) {
+    return name_ == other_typed->name_ && type_ == other_typed->type_;
+  }
+  return false;
+}
+
+static StringRef get_random_id_attribute_name(const eAttrDomain domain)
+{
+  switch (domain) {
+    case ATTR_DOMAIN_POINT:
+    case ATTR_DOMAIN_INSTANCE:
+      return "id";
+    default:
+      return "";
+  }
+}
+
+GVArray IDAttributeFieldInput::get_varray_for_context(const GeometryFieldContext &context,
+                                                      const IndexMask mask) const
+{
+
+  const StringRef name = get_random_id_attribute_name(context.domain());
+  if (auto attributes = context.attributes()) {
+    if (GVArray attribute = attributes->lookup(name, context.domain(), CD_PROP_INT32)) {
+      return attribute;
+    }
+  }
+
+  /* Use the index as the fallback if no random ID attribute exists. */
+  return fn::IndexFieldInput::get_index_varray(mask);
+}
+
+std::string IDAttributeFieldInput::socket_inspection_name() const
+{
+  return TIP_("ID / Index");
+}
+
+uint64_t IDAttributeFieldInput::hash() const
+{
+  /* All random ID attribute inputs are the same within the same evaluation context. */
+  return 92386459827;
+}
+
+bool IDAttributeFieldInput::is_equal_to(const fn::FieldNode &other) const
+{
+  /* All random ID attribute inputs are the same within the same evaluation context. */
+  return dynamic_cast(&other) != nullptr;
+}
+
+GVArray AnonymousAttributeFieldInput::get_varray_for_context(const GeometryFieldContext &context,
+                                                             const IndexMask /*mask*/) const
+{
+  const eCustomDataType data_type = cpp_type_to_custom_data_type(*type_);
+  return context.attributes()->lookup(anonymous_id_.get(), context.domain(), data_type);
+}
+
+std::string AnonymousAttributeFieldInput::socket_inspection_name() const
+{
+  std::stringstream ss;
+  ss << '"' << debug_name_ << '"' << TIP_(" from ") << producer_name_;
+  return ss.str();
+}
+
+uint64_t AnonymousAttributeFieldInput::hash() const
+{
+  return get_default_hash_2(anonymous_id_.get(), type_);
+}
+
+bool AnonymousAttributeFieldInput::is_equal_to(const fn::FieldNode &other) const
+{
+  if (const AnonymousAttributeFieldInput *other_typed =
+          dynamic_cast(&other)) {
+    return anonymous_id_.get() == other_typed->anonymous_id_.get() && type_ == other_typed->type_;
+  }
+  return false;
+}
+
+}  // namespace blender::bke
+
+/* -------------------------------------------------------------------- */
+/** \name Mesh and Curve Normals Field Input
+ * \{ */
+
+namespace blender::bke {
+
+GVArray NormalFieldInput::get_varray_for_context(const GeometryFieldContext &context,
+                                                 const IndexMask mask) const
+{
+  if (const Mesh *mesh = context.mesh()) {
+    return mesh_normals_varray(*mesh, mask, context.domain());
+  }
+  if (const CurvesGeometry *curves = context.curves()) {
+    return curve_normals_varray(*curves, context.domain());
+  }
+  return {};
+}
+
+std::string NormalFieldInput::socket_inspection_name() const
+{
+  return TIP_("Normal");
+}
+
+uint64_t NormalFieldInput::hash() const
+{
+  return 213980475983;
+}
+
+bool NormalFieldInput::is_equal_to(const fn::FieldNode &other) const
+{
+  return dynamic_cast(&other) != nullptr;
+}
+
+}  // namespace blender::bke
+
+/** \} */
diff --git a/source/blender/blenkernel/intern/geometry_set.cc b/source/blender/blenkernel/intern/geometry_set.cc
index c6fe8eebc7f..46ff8141504 100644
--- a/source/blender/blenkernel/intern/geometry_set.cc
+++ b/source/blender/blenkernel/intern/geometry_set.cc
@@ -8,7 +8,6 @@
 
 #include "BKE_attribute.h"
 #include "BKE_curves.hh"
-#include "BKE_geometry_fields.hh"
 #include "BKE_geometry_set.hh"
 #include "BKE_lib_id.h"
 #include "BKE_mesh.h"
@@ -19,6 +18,7 @@
 
 #include "DNA_collection_types.h"
 #include "DNA_object_types.h"
+#include "DNA_pointcloud_types.h"
 
 #include "BLI_rand.hh"
 
@@ -53,6 +53,8 @@ GeometryComponent *GeometryComponent::create(GeometryComponentType component_typ
       return new VolumeComponent();
     case GEO_COMPONENT_TYPE_CURVE:
       return new CurveComponent();
+    case GEO_COMPONENT_TYPE_EDIT:
+      return new GeometryComponentEditData();
   }
   BLI_assert_unreachable();
   return nullptr;
@@ -175,6 +177,20 @@ void GeometrySet::keep_only(const blender::Span component
   }
 }
 
+void GeometrySet::keep_only_during_modify(
+    const blender::Span component_types)
+{
+  Vector extended_types = component_types;
+  extended_types.append_non_duplicates(GEO_COMPONENT_TYPE_INSTANCES);
+  extended_types.append_non_duplicates(GEO_COMPONENT_TYPE_EDIT);
+  this->keep_only(extended_types);
+}
+
+void GeometrySet::remove_geometry_during_modify()
+{
+  this->keep_only_during_modify({});
+}
+
 void GeometrySet::add(const GeometryComponent &component)
 {
   BLI_assert(!components_[component.type()]);
@@ -222,8 +238,40 @@ bool GeometrySet::compute_boundbox_without_instances(float3 *r_min, float3 *r_ma
 
 std::ostream &operator<<(std::ostream &stream, const GeometrySet &geometry_set)
 {
-  stream << "";
+  Vector parts;
+  if (const Mesh *mesh = geometry_set.get_mesh_for_read()) {
+    parts.append(std::to_string(mesh->totvert) + " verts");
+    parts.append(std::to_string(mesh->totedge) + " edges");
+    parts.append(std::to_string(mesh->totpoly) + " polys");
+    parts.append(std::to_string(mesh->totloop) + " corners");
+  }
+  if (const Curves *curves = geometry_set.get_curves_for_read()) {
+    parts.append(std::to_string(curves->geometry.point_num) + " control points");
+    parts.append(std::to_string(curves->geometry.curve_num) + " curves");
+  }
+  if (const PointCloud *point_cloud = geometry_set.get_pointcloud_for_read()) {
+    parts.append(std::to_string(point_cloud->totpoint) + " points");
+  }
+  if (const Volume *volume = geometry_set.get_volume_for_read()) {
+    parts.append(std::to_string(BKE_volume_num_grids(volume)) + " volume grids");
+  }
+  if (geometry_set.has_instances()) {
+    parts.append(std::to_string(
+                     geometry_set.get_component_for_read()->instances_num()) +
+                 " instances");
+  }
+  if (geometry_set.get_curve_edit_hints_for_read()) {
+    parts.append("curve edit hints");
+  }
+
+  stream << "";
   return stream;
 }
 
@@ -290,6 +338,13 @@ const Curves *GeometrySet::get_curves_for_read() const
   return (component == nullptr) ? nullptr : component->get_for_read();
 }
 
+const blender::bke::CurvesEditHints *GeometrySet::get_curve_edit_hints_for_read() const
+{
+  const GeometryComponentEditData *component =
+      this->get_component_for_read();
+  return (component == nullptr) ? nullptr : component->curves_edit_hints_.get();
+}
+
 bool GeometrySet::has_pointcloud() const
 {
   const PointCloudComponent *component = this->get_component_for_read();
@@ -453,6 +508,16 @@ Curves *GeometrySet::get_curves_for_write()
   return component == nullptr ? nullptr : component->get_for_write();
 }
 
+blender::bke::CurvesEditHints *GeometrySet::get_curve_edit_hints_for_write()
+{
+  if (!this->has()) {
+    return nullptr;
+  }
+  GeometryComponentEditData &component =
+      this->get_component_for_write();
+  return component.curves_edit_hints_.get();
+}
+
 void GeometrySet::attribute_foreach(const Span component_types,
                                     const bool include_instances,
                                     const AttributeForeachCallback callback) const
@@ -600,48 +665,6 @@ void GeometrySet::modify_geometry_sets(ForeachSubGeometryCallback callback)
 
 /** \} */
 
-/* -------------------------------------------------------------------- */
-/** \name Mesh and Curve Normals Field Input
- * \{ */
-
-namespace blender::bke {
-
-GVArray NormalFieldInput::get_varray_for_context(const GeometryComponent &component,
-                                                 const eAttrDomain domain,
-                                                 IndexMask mask) const
-{
-  if (component.type() == GEO_COMPONENT_TYPE_MESH) {
-    const MeshComponent &mesh_component = static_cast(component);
-    if (const Mesh *mesh = mesh_component.get_for_read()) {
-      return mesh_normals_varray(mesh_component, *mesh, mask, domain);
-    }
-  }
-  else if (component.type() == GEO_COMPONENT_TYPE_CURVE) {
-    const CurveComponent &curve_component = static_cast(component);
-    return curve_normals_varray(curve_component, domain);
-  }
-  return {};
-}
-
-std::string NormalFieldInput::socket_inspection_name() const
-{
-  return TIP_("Normal");
-}
-
-uint64_t NormalFieldInput::hash() const
-{
-  return 213980475983;
-}
-
-bool NormalFieldInput::is_equal_to(const fn::FieldNode &other) const
-{
-  return dynamic_cast(&other) != nullptr;
-}
-
-}  // namespace blender::bke
-
-/** \} */
-
 /* -------------------------------------------------------------------- */
 /** \name C API
  * \{ */
@@ -679,6 +702,8 @@ bool BKE_object_has_geometry_set_instances(const Object *ob)
       case GEO_COMPONENT_TYPE_CURVE:
         is_instance = !ELEM(ob->type, OB_CURVES_LEGACY, OB_FONT);
         break;
+      case GEO_COMPONENT_TYPE_EDIT:
+        break;
     }
     if (is_instance) {
       return true;
diff --git a/source/blender/blenkernel/intern/geometry_set_instances.cc b/source/blender/blenkernel/intern/geometry_set_instances.cc
index fbd676e4bee..df48a99f706 100644
--- a/source/blender/blenkernel/intern/geometry_set_instances.cc
+++ b/source/blender/blenkernel/intern/geometry_set_instances.cc
@@ -27,8 +27,8 @@ static void geometry_set_collect_recursive_collection(const Collection &collecti
 
 static void add_final_mesh_as_geometry_component(const Object &object, GeometrySet &geometry_set)
 {
-  Mesh *mesh = BKE_modifier_get_evaluated_mesh_from_evaluated_object(&const_cast(object),
-                                                                     false);
+  Mesh *mesh = BKE_modifier_get_evaluated_mesh_from_evaluated_object(
+      &const_cast(object));
 
   if (mesh != nullptr) {
     BKE_mesh_wrapper_ensure_mdata(mesh);
diff --git a/source/blender/blenkernel/intern/gpencil.c b/source/blender/blenkernel/intern/gpencil.c
index 3d546c5c36a..f6082d886d9 100644
--- a/source/blender/blenkernel/intern/gpencil.c
+++ b/source/blender/blenkernel/intern/gpencil.c
@@ -271,7 +271,7 @@ static void greasepencil_blend_read_lib(BlendLibReader *reader, ID *id)
 {
   bGPdata *gpd = (bGPdata *)id;
 
-  /* Relink all data-lock linked by GP data-lock */
+  /* Relink all data-block linked by GP data-block. */
   /* Layers */
   LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd->layers) {
     /* Layer -> Parent References */
@@ -314,7 +314,7 @@ IDTypeInfo IDType_ID_GD = {
     .foreach_id = greasepencil_foreach_id,
     .foreach_cache = NULL,
     .foreach_path = NULL,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = greasepencil_blend_write,
     .blend_read_data = greasepencil_blend_read_data,
@@ -675,7 +675,7 @@ bGPDlayer *BKE_gpencil_layer_addnew(bGPdata *gpd,
   }
 
   /* auto-name */
-  BLI_strncpy(gpl->info, name, sizeof(gpl->info));
+  BLI_strncpy(gpl->info, DATA_(name), sizeof(gpl->info));
   BLI_uniquename(&gpd->layers,
                  gpl,
                  (gpd->flag & GP_DATA_ANNOTATIONS) ? DATA_("Note") : DATA_("GP_Layer"),
diff --git a/source/blender/blenkernel/intern/gpencil_curve.c b/source/blender/blenkernel/intern/gpencil_curve.c
index d68b322e4c5..bf224a9613e 100644
--- a/source/blender/blenkernel/intern/gpencil_curve.c
+++ b/source/blender/blenkernel/intern/gpencil_curve.c
@@ -337,7 +337,6 @@ static void gpencil_convert_spline(Main *bmain,
   /* Add stroke to frame. */
   BLI_addtail(&gpf->strokes, gps);
 
-  float *coord_array = NULL;
   float init_co[3];
 
   switch (nu->type) {
@@ -376,8 +375,7 @@ static void gpencil_convert_spline(Main *bmain,
         BezTriple *bezt = &nu->bezt[inext];
         bool last = (bool)(s == segments - 1);
 
-        coord_array = MEM_callocN((size_t)3 * resolu * sizeof(float), __func__);
-
+        float *coord_array = MEM_callocN(sizeof(float[3]) * resolu, __func__);
         for (int j = 0; j < 3; j++) {
           BKE_curve_forward_diff_bezier(prevbezt->vec[1][j],
                                         prevbezt->vec[2][j],
@@ -397,8 +395,9 @@ static void gpencil_convert_spline(Main *bmain,
 
         gpencil_add_new_points(
             gps, coord_array, radius_start, radius_end, init, resolu, init_co, last);
+
         /* Free memory. */
-        MEM_SAFE_FREE(coord_array);
+        MEM_freeN(coord_array);
 
         /* As the last point of segment is the first point of next segment, back one array
          * element to avoid duplicated points on the same location.
@@ -419,7 +418,7 @@ static void gpencil_convert_spline(Main *bmain,
           nurb_points = (nu->pntsu - 1) * resolu;
         }
         /* Get all curve points. */
-        coord_array = MEM_callocN(sizeof(float[3]) * nurb_points, __func__);
+        float *coord_array = MEM_callocN(sizeof(float[3]) * nurb_points, __func__);
         BKE_nurb_makeCurve(nu, coord_array, NULL, NULL, NULL, resolu, sizeof(float[3]));
 
         /* Allocate memory for storage points. */
@@ -429,7 +428,7 @@ static void gpencil_convert_spline(Main *bmain,
         /* Add points. */
         gpencil_add_new_points(gps, coord_array, 1.0f, 1.0f, 0, gps->totpoints, init_co, false);
 
-        MEM_SAFE_FREE(coord_array);
+        MEM_freeN(coord_array);
       }
       break;
     }
diff --git a/source/blender/blenkernel/intern/gpencil_geom.cc b/source/blender/blenkernel/intern/gpencil_geom.cc
index d0075a7d161..4d0db4d5386 100644
--- a/source/blender/blenkernel/intern/gpencil_geom.cc
+++ b/source/blender/blenkernel/intern/gpencil_geom.cc
@@ -35,6 +35,7 @@
 
 #include "BLT_translation.h"
 
+#include "BKE_attribute.hh"
 #include "BKE_context.h"
 #include "BKE_deform.h"
 #include "BKE_gpencil.h"
@@ -2463,6 +2464,9 @@ static void gpencil_generate_edgeloops(Object *ob,
   if (me->totedge == 0) {
     return;
   }
+  const Span verts = me->verts();
+  const Span edges = me->edges();
+  const Span dverts = me->deform_verts();
   const float(*vert_normals)[3] = BKE_mesh_vertex_normals_ensure(me);
 
   /* Arrays for all edge vertices (forward and backward) that form a edge loop.
@@ -2475,15 +2479,15 @@ static void gpencil_generate_edgeloops(Object *ob,
   GpEdge *gp_edges = (GpEdge *)MEM_callocN(sizeof(GpEdge) * me->totedge, __func__);
   GpEdge *gped = nullptr;
   for (int i = 0; i < me->totedge; i++) {
-    MEdge *ed = &me->medge[i];
+    const MEdge *ed = &edges[i];
     gped = &gp_edges[i];
-    MVert *mv1 = &me->mvert[ed->v1];
+    const MVert *mv1 = &verts[ed->v1];
     copy_v3_v3(gped->n1, vert_normals[ed->v1]);
 
     gped->v1 = ed->v1;
     copy_v3_v3(gped->v1_co, mv1->co);
 
-    MVert *mv2 = &me->mvert[ed->v2];
+    const MVert *mv2 = &verts[ed->v2];
     copy_v3_v3(gped->n2, vert_normals[ed->v2]);
     gped->v2 = ed->v2;
     copy_v3_v3(gped->v2_co, mv2->co);
@@ -2539,8 +2543,7 @@ static void gpencil_generate_edgeloops(Object *ob,
         gpf_stroke, MAX2(stroke_mat_index, 0), array_len + 1, thickness * thickness, false);
 
     /* Create dvert data. */
-    MDeformVert *me_dvert = me->dvert;
-    if (use_vgroups && me_dvert) {
+    if (use_vgroups && !dverts.is_empty()) {
       gps_stroke->dvert = (MDeformVert *)MEM_callocN(sizeof(MDeformVert) * (array_len + 1),
                                                      "gp_stroke_dverts");
     }
@@ -2549,7 +2552,7 @@ static void gpencil_generate_edgeloops(Object *ob,
     float fpt[3];
     for (int i = 0; i < array_len + 1; i++) {
       int vertex_index = i == 0 ? gp_edges[stroke[0]].v1 : gp_edges[stroke[i - 1]].v2;
-      MVert *mv = &me->mvert[vertex_index];
+      const MVert *mv = &verts[vertex_index];
 
       /* Add segment. */
       bGPDspoint *pt = &gps_stroke->points[i];
@@ -2562,9 +2565,9 @@ static void gpencil_generate_edgeloops(Object *ob,
       pt->strength = 1.0f;
 
       /* Copy vertex groups from mesh. Assuming they already exist in the same order. */
-      if (use_vgroups && me_dvert) {
+      if (use_vgroups && !dverts.is_empty()) {
         MDeformVert *dv = &gps_stroke->dvert[i];
-        MDeformVert *src_dv = &me_dvert[vertex_index];
+        const MDeformVert *src_dv = &dverts[vertex_index];
         dv->totweight = src_dv->totweight;
         dv->dw = (MDeformWeight *)MEM_callocN(sizeof(MDeformWeight) * dv->totweight,
                                               "gp_stroke_dverts_dw");
@@ -2662,6 +2665,8 @@ bool BKE_gpencil_convert_mesh(Main *bmain,
                               const bool use_faces,
                               const bool use_vgroups)
 {
+  using namespace blender;
+  using namespace blender::bke;
   if (ELEM(nullptr, ob_gp, ob_mesh) || (ob_gp->type != OB_GPENCIL) || (ob_gp->data == nullptr)) {
     return false;
   }
@@ -2671,8 +2676,9 @@ bool BKE_gpencil_convert_mesh(Main *bmain,
   /* Use evaluated data to get mesh with all modifiers on top. */
   Object *ob_eval = (Object *)DEG_get_evaluated_object(depsgraph, ob_mesh);
   const Mesh *me_eval = BKE_object_get_evaluated_mesh(ob_eval);
-  const MPoly *mpoly = me_eval->mpoly;
-  const MLoop *mloop = me_eval->mloop;
+  const Span verts = me_eval->verts();
+  const Span polys = me_eval->polys();
+  const Span loops = me_eval->loops();
   int mpoly_len = me_eval->totpoly;
   char element_name[200];
 
@@ -2708,12 +2714,15 @@ bool BKE_gpencil_convert_mesh(Main *bmain,
     bGPDframe *gpf_fill = BKE_gpencil_layer_frame_get(
         gpl_fill, scene->r.cfra + frame_offset, GP_GETFRAME_ADD_NEW);
     int i;
+
+    const VArray mesh_material_indices = me_eval->attributes().lookup_or_default(
+        "material_index", ATTR_DOMAIN_FACE, 0);
     for (i = 0; i < mpoly_len; i++) {
-      const MPoly *mp = &mpoly[i];
+      const MPoly *mp = &polys[i];
 
       /* Find material. */
       int mat_idx = 0;
-      Material *ma = BKE_object_material_get(ob_mesh, mp->mat_nr + 1);
+      Material *ma = BKE_object_material_get(ob_mesh, mesh_material_indices[i] + 1);
       make_element_name(
           ob_mesh->id.name + 2, (ma != nullptr) ? ma->id.name + 2 : "Fill", 64, element_name);
       mat_idx = BKE_gpencil_material_find_index_by_name_prefix(ob_gp, element_name);
@@ -2733,16 +2742,16 @@ bool BKE_gpencil_convert_mesh(Main *bmain,
       gps_fill->flag |= GP_STROKE_CYCLIC;
 
       /* Create dvert data. */
-      MDeformVert *me_dvert = me_eval->dvert;
-      if (use_vgroups && me_dvert) {
+      const Span dverts = me_eval->deform_verts();
+      if (use_vgroups && !dverts.is_empty()) {
         gps_fill->dvert = (MDeformVert *)MEM_callocN(sizeof(MDeformVert) * mp->totloop,
                                                      "gp_fill_dverts");
       }
 
       /* Add points to strokes. */
       for (int j = 0; j < mp->totloop; j++) {
-        const MLoop *ml = &mloop[mp->loopstart + j];
-        const MVert *mv = &me_eval->mvert[ml->v];
+        const MLoop *ml = &loops[mp->loopstart + j];
+        const MVert *mv = &verts[ml->v];
 
         bGPDspoint *pt = &gps_fill->points[j];
         copy_v3_v3(&pt->x, mv->co);
@@ -2751,9 +2760,9 @@ bool BKE_gpencil_convert_mesh(Main *bmain,
         pt->strength = 1.0f;
 
         /* Copy vertex groups from mesh. Assuming they already exist in the same order. */
-        if (use_vgroups && me_dvert) {
+        if (use_vgroups && !dverts.is_empty()) {
           MDeformVert *dv = &gps_fill->dvert[j];
-          MDeformVert *src_dv = &me_dvert[ml->v];
+          const MDeformVert *src_dv = &dverts[ml->v];
           dv->totweight = src_dv->totweight;
           dv->dw = (MDeformWeight *)MEM_callocN(sizeof(MDeformWeight) * dv->totweight,
                                                 "gp_fill_dverts_dw");
@@ -3409,7 +3418,8 @@ void BKE_gpencil_stroke_join(bGPDstroke *gps_a,
                              bGPDstroke *gps_b,
                              const bool leave_gaps,
                              const bool fit_thickness,
-                             const bool smooth)
+                             const bool smooth,
+                             bool auto_flip)
 {
   bGPDspoint point;
   bGPDspoint *pt;
@@ -3426,52 +3436,54 @@ void BKE_gpencil_stroke_join(bGPDstroke *gps_a,
     return;
   }
 
-  /* define start and end points of each stroke */
-  float start_a[3], start_b[3], end_a[3], end_b[3];
-  pt = &gps_a->points[0];
-  copy_v3_v3(start_a, &pt->x);
+  if (auto_flip) {
+    /* define start and end points of each stroke */
+    float start_a[3], start_b[3], end_a[3], end_b[3];
+    pt = &gps_a->points[0];
+    copy_v3_v3(start_a, &pt->x);
 
-  pt = &gps_a->points[gps_a->totpoints - 1];
-  copy_v3_v3(end_a, &pt->x);
+    pt = &gps_a->points[gps_a->totpoints - 1];
+    copy_v3_v3(end_a, &pt->x);
 
-  pt = &gps_b->points[0];
-  copy_v3_v3(start_b, &pt->x);
+    pt = &gps_b->points[0];
+    copy_v3_v3(start_b, &pt->x);
 
-  pt = &gps_b->points[gps_b->totpoints - 1];
-  copy_v3_v3(end_b, &pt->x);
+    pt = &gps_b->points[gps_b->totpoints - 1];
+    copy_v3_v3(end_b, &pt->x);
 
-  /* Check if need flip strokes. */
-  float dist = len_squared_v3v3(end_a, start_b);
-  bool flip_a = false;
-  bool flip_b = false;
-  float lowest = dist;
+    /* Check if need flip strokes. */
+    float dist = len_squared_v3v3(end_a, start_b);
+    bool flip_a = false;
+    bool flip_b = false;
+    float lowest = dist;
 
-  dist = len_squared_v3v3(end_a, end_b);
-  if (dist < lowest) {
-    lowest = dist;
-    flip_a = false;
-    flip_b = true;
-  }
+    dist = len_squared_v3v3(end_a, end_b);
+    if (dist < lowest) {
+      lowest = dist;
+      flip_a = false;
+      flip_b = true;
+    }
 
-  dist = len_squared_v3v3(start_a, start_b);
-  if (dist < lowest) {
-    lowest = dist;
-    flip_a = true;
-    flip_b = false;
-  }
+    dist = len_squared_v3v3(start_a, start_b);
+    if (dist < lowest) {
+      lowest = dist;
+      flip_a = true;
+      flip_b = false;
+    }
 
-  dist = len_squared_v3v3(start_a, end_b);
-  if (dist < lowest) {
-    lowest = dist;
-    flip_a = true;
-    flip_b = true;
-  }
+    dist = len_squared_v3v3(start_a, end_b);
+    if (dist < lowest) {
+      lowest = dist;
+      flip_a = true;
+      flip_b = true;
+    }
 
-  if (flip_a) {
-    BKE_gpencil_stroke_flip(gps_a);
-  }
-  if (flip_b) {
-    BKE_gpencil_stroke_flip(gps_b);
+    if (flip_a) {
+      BKE_gpencil_stroke_flip(gps_a);
+    }
+    if (flip_b) {
+      BKE_gpencil_stroke_flip(gps_b);
+    }
   }
 
   /* don't visibly link the first and last points? */
@@ -3534,6 +3546,27 @@ void BKE_gpencil_stroke_join(bGPDstroke *gps_a,
   }
 }
 
+void BKE_gpencil_stroke_start_set(bGPDstroke *gps, int start_idx)
+{
+  if ((start_idx < 1) || (start_idx >= gps->totpoints) || (gps->totpoints < 2)) {
+    return;
+  }
+
+  /* Only cyclic strokes. */
+  if ((gps->flag & GP_STROKE_CYCLIC) == 0) {
+    return;
+  }
+
+  bGPDstroke *gps_b = BKE_gpencil_stroke_duplicate(gps, true, false);
+  BKE_gpencil_stroke_trim_points(gps_b, 0, start_idx - 1);
+  BKE_gpencil_stroke_trim_points(gps, start_idx, gps->totpoints - 1);
+
+  /* Join both strokes. */
+  BKE_gpencil_stroke_join(gps, gps_b, false, false, false, false);
+
+  BKE_gpencil_free_stroke(gps_b);
+}
+
 void BKE_gpencil_stroke_copy_to_keyframes(
     bGPdata *gpd, bGPDlayer *gpl, bGPDframe *gpf, bGPDstroke *gps, const bool tail)
 {
@@ -3761,8 +3794,8 @@ void BKE_gpencil_stroke_uniform_subdivide(bGPdata *gpd,
   BKE_gpencil_stroke_geometry_update(gpd, gps);
 }
 
-void BKE_gpencil_stroke_to_view_space(RegionView3D *rv3d,
-                                      bGPDstroke *gps,
+void BKE_gpencil_stroke_to_view_space(bGPDstroke *gps,
+                                      float viewmat[4][4],
                                       const float diff_mat[4][4])
 {
   for (int i = 0; i < gps->totpoints; i++) {
@@ -3770,12 +3803,12 @@ void BKE_gpencil_stroke_to_view_space(RegionView3D *rv3d,
     /* Point to parent space. */
     mul_v3_m4v3(&pt->x, diff_mat, &pt->x);
     /* point to view space */
-    mul_m4_v3(rv3d->viewmat, &pt->x);
+    mul_m4_v3(viewmat, &pt->x);
   }
 }
 
-void BKE_gpencil_stroke_from_view_space(RegionView3D *rv3d,
-                                        bGPDstroke *gps,
+void BKE_gpencil_stroke_from_view_space(bGPDstroke *gps,
+                                        float viewinv[4][4],
                                         const float diff_mat[4][4])
 {
   float inverse_diff_mat[4][4];
@@ -3783,7 +3816,7 @@ void BKE_gpencil_stroke_from_view_space(RegionView3D *rv3d,
 
   for (int i = 0; i < gps->totpoints; i++) {
     bGPDspoint *pt = &gps->points[i];
-    mul_v3_m4v3(&pt->x, rv3d->viewinv, &pt->x);
+    mul_v3_m4v3(&pt->x, viewinv, &pt->x);
     mul_m4_v3(inverse_diff_mat, &pt->x);
   }
 }
@@ -3960,6 +3993,7 @@ static ListBase *gpencil_stroke_perimeter_ex(const bGPdata *gpd,
                                              const bGPDlayer *gpl,
                                              const bGPDstroke *gps,
                                              int subdivisions,
+                                             const float thickness_chg,
                                              int *r_num_perimeter_points)
 {
   /* sanity check */
@@ -3968,7 +4002,9 @@ static ListBase *gpencil_stroke_perimeter_ex(const bGPdata *gpd,
   }
 
   float defaultpixsize = 1000.0f / gpd->pixfactor;
+  float ovr_radius = thickness_chg / defaultpixsize / 2.0f;
   float stroke_radius = ((gps->thickness + gpl->line_change) / defaultpixsize) / 2.0f;
+  stroke_radius = max_ff(stroke_radius - ovr_radius, 0.0f);
 
   ListBase *perimeter_right_side = MEM_cnew(__func__);
   ListBase *perimeter_left_side = MEM_cnew(__func__);
@@ -4197,16 +4233,21 @@ static ListBase *gpencil_stroke_perimeter_ex(const bGPdata *gpd,
   return perimeter_list;
 }
 
-bGPDstroke *BKE_gpencil_stroke_perimeter_from_view(struct RegionView3D *rv3d,
+bGPDstroke *BKE_gpencil_stroke_perimeter_from_view(float viewmat[4][4],
                                                    bGPdata *gpd,
                                                    const bGPDlayer *gpl,
                                                    bGPDstroke *gps,
                                                    const int subdivisions,
-                                                   const float diff_mat[4][4])
+                                                   const float diff_mat[4][4],
+                                                   const float thickness_chg)
 {
   if (gps->totpoints == 0) {
     return nullptr;
   }
+
+  float viewinv[4][4];
+  invert_m4_m4(viewinv, viewmat);
+
   /* Duplicate only points and fill data. Weight and Curve are not needed. */
   bGPDstroke *gps_temp = (bGPDstroke *)MEM_dupallocN(gps);
   gps_temp->prev = gps_temp->next = nullptr;
@@ -4231,10 +4272,10 @@ bGPDstroke *BKE_gpencil_stroke_perimeter_from_view(struct RegionView3D *rv3d,
     pt_dst->uv_rot = 0;
   }
 
-  BKE_gpencil_stroke_to_view_space(rv3d, gps_temp, diff_mat);
+  BKE_gpencil_stroke_to_view_space(gps_temp, viewmat, diff_mat);
   int num_perimeter_points = 0;
   ListBase *perimeter_points = gpencil_stroke_perimeter_ex(
-      gpd, gpl, gps_temp, subdivisions, &num_perimeter_points);
+      gpd, gpl, gps_temp, subdivisions, thickness_chg, &num_perimeter_points);
 
   if (num_perimeter_points == 0) {
     return nullptr;
@@ -4254,7 +4295,7 @@ bGPDstroke *BKE_gpencil_stroke_perimeter_from_view(struct RegionView3D *rv3d,
     pt->flag |= GP_SPOINT_SELECT;
   }
 
-  BKE_gpencil_stroke_from_view_space(rv3d, perimeter_stroke, diff_mat);
+  BKE_gpencil_stroke_from_view_space(perimeter_stroke, viewinv, diff_mat);
 
   /* Free temp data. */
   BLI_freelistN(perimeter_points);
diff --git a/source/blender/blenkernel/intern/gpencil_modifier.c b/source/blender/blenkernel/intern/gpencil_modifier.c
index 8739f2f7082..33f84aff545 100644
--- a/source/blender/blenkernel/intern/gpencil_modifier.c
+++ b/source/blender/blenkernel/intern/gpencil_modifier.c
@@ -95,7 +95,7 @@ void BKE_gpencil_cache_data_init(Depsgraph *depsgraph, Object *ob)
           MEM_SAFE_FREE(mmd->cache_data);
         }
         Object *ob_target = DEG_get_evaluated_object(depsgraph, ob);
-        Mesh *target = BKE_modifier_get_evaluated_mesh_from_evaluated_object(ob_target, false);
+        Mesh *target = BKE_modifier_get_evaluated_mesh_from_evaluated_object(ob_target);
         mmd->cache_data = MEM_callocN(sizeof(ShrinkwrapTreeData), __func__);
         if (BKE_shrinkwrap_init_tree(
                 mmd->cache_data, target, mmd->shrink_type, mmd->shrink_mode, false)) {
@@ -360,7 +360,8 @@ GpencilModifierData *BKE_gpencil_modifier_new(int type)
   md->type = type;
   md->mode = eGpencilModifierMode_Realtime | eGpencilModifierMode_Render;
   md->flag = eGpencilModifierFlag_OverrideLibrary_Local;
-  md->ui_expand_flag = 1; /* Only expand the parent panel at first. */
+  /* Only expand the parent panel at first. */
+  md->ui_expand_flag = UI_PANEL_DATA_EXPAND_ROOT;
 
   if (mti->flags & eGpencilModifierTypeFlag_EnableInEditmode) {
     md->mode |= eGpencilModifierMode_Editmode;
@@ -694,7 +695,7 @@ static void gpencil_copy_visible_frames_to_eval(Depsgraph *depsgraph, Scene *sce
       gpl_eval->actframe = BKE_gpencil_layer_frame_get(gpl_eval, remap_cfra, GP_GETFRAME_USE_PREV);
     }
     /* Always copy active frame to eval, because the modifiers always evaluate the active frame,
-     * even if it's not visible (e.g. the layer is hidden).*/
+     * even if it's not visible (e.g. the layer is hidden). */
     if (gpl_eval->actframe != NULL) {
       copy_frame_to_eval_ex(gpl_eval->actframe->runtime.gpf_orig, gpl_eval->actframe);
     }
diff --git a/source/blender/blenkernel/intern/icons_rasterize.c b/source/blender/blenkernel/intern/icons_rasterize.c
index 5603d84022d..00dbdcfa1e5 100644
--- a/source/blender/blenkernel/intern/icons_rasterize.c
+++ b/source/blender/blenkernel/intern/icons_rasterize.c
@@ -76,7 +76,7 @@ ImBuf *BKE_icon_geom_rasterize(const struct Icon_Geom *geom,
   const uchar(*pos)[2] = geom->coords;
   const uint *col = (void *)geom->colors;
 
-  /* TODO(campbell): Currently rasterizes to fixed size, then scales.
+  /* TODO(@campbellbarton): Currently rasterizes to fixed size, then scales.
    * Should rasterize to double size for eg instead. */
   const int rect_size[2] = {max_ii(256, (int)size_x * 2), max_ii(256, (int)size_y * 2)};
 
diff --git a/source/blender/blenkernel/intern/idprop.c b/source/blender/blenkernel/intern/idprop.c
index 35f02c29a00..98c317c547b 100644
--- a/source/blender/blenkernel/intern/idprop.c
+++ b/source/blender/blenkernel/intern/idprop.c
@@ -784,7 +784,7 @@ IDProperty *IDP_GetProperties(ID *id, const bool create_if_needed)
   if (create_if_needed) {
     id->properties = MEM_callocN(sizeof(IDProperty), "IDProperty");
     id->properties->type = IDP_GROUP;
-    /* NOTE(campbell): Don't overwrite the data's name and type
+    /* NOTE(@campbellbarton): Don't overwrite the data's name and type
      * some functions might need this if they
      * don't have a real ID, should be named elsewhere. */
     // strcpy(id->name, "top_level_group");
@@ -1428,7 +1428,7 @@ void IDP_BlendReadData_impl(BlendDataReader *reader, IDProperty **prop, const ch
   }
 }
 
-void IDP_BlendReadLib(BlendLibReader *reader, IDProperty *prop)
+void IDP_BlendReadLib(BlendLibReader *reader, Library *lib, IDProperty *prop)
 {
   if (!prop) {
     return;
@@ -1437,7 +1437,7 @@ void IDP_BlendReadLib(BlendLibReader *reader, IDProperty *prop)
   switch (prop->type) {
     case IDP_ID: /* PointerProperty */
     {
-      void *newaddr = BLO_read_get_new_id_address(reader, NULL, IDP_Id(prop));
+      void *newaddr = BLO_read_get_new_id_address(reader, lib, IDP_Id(prop));
       if (IDP_Id(prop) && !newaddr && G.debug) {
         printf("Error while loading \"%s\". Data not found in file!\n", prop->name);
       }
@@ -1448,14 +1448,14 @@ void IDP_BlendReadLib(BlendLibReader *reader, IDProperty *prop)
     {
       IDProperty *idp_array = IDP_IDPArray(prop);
       for (int i = 0; i < prop->len; i++) {
-        IDP_BlendReadLib(reader, &(idp_array[i]));
+        IDP_BlendReadLib(reader, lib, &(idp_array[i]));
       }
       break;
     }
     case IDP_GROUP: /* PointerProperty */
     {
       LISTBASE_FOREACH (IDProperty *, loop, &prop->data.group) {
-        IDP_BlendReadLib(reader, loop);
+        IDP_BlendReadLib(reader, lib, loop);
       }
       break;
     }
diff --git a/source/blender/blenkernel/intern/idprop_create.cc b/source/blender/blenkernel/intern/idprop_create.cc
index f549393fd12..8a6e5cdcc50 100644
--- a/source/blender/blenkernel/intern/idprop_create.cc
+++ b/source/blender/blenkernel/intern/idprop_create.cc
@@ -44,6 +44,14 @@ std::unique_ptr create(const StringRefNull prop_n
   return std::unique_ptr(property);
 }
 
+std::unique_ptr create(const StringRefNull prop_name, ID *value)
+{
+  IDPropertyTemplate prop_template{0};
+  prop_template.id = value;
+  IDProperty *property = IDP_New(IDP_ID, &prop_template, prop_name.c_str());
+  return std::unique_ptr(property);
+}
+
 static std::unique_ptr array_create(const StringRefNull prop_name,
                                                                    eIDPropertyType subtype,
                                                                    size_t array_len)
@@ -71,12 +79,12 @@ static void array_values_set(IDProperty *property,
 template<
     /** C-Primitive type of the array. Can be int32_t, float, double. */
     typename PrimitiveType,
-    /** Subtype of the ID_ARRAY. Must match PrimitiveType. */
+    /** Sub-type of the #ID_ARRAY. Must match #PrimitiveType. */
     eIDPropertyType id_property_subtype>
 std::unique_ptr create_array(StringRefNull prop_name,
                                                             Span values)
 {
-  static_assert(std::is_same_v || std::is_same_v ||
+  static_assert(std::is_same_v || std::is_same_v ||
                     std::is_same_v,
                 "Allowed values for PrimitiveType are int32_t, float and double.");
   static_assert(!std::is_same_v || id_property_subtype == IDP_INT,
diff --git a/source/blender/blenkernel/intern/idtype.c b/source/blender/blenkernel/intern/idtype.c
index e55143d6852..923582dff4c 100644
--- a/source/blender/blenkernel/intern/idtype.c
+++ b/source/blender/blenkernel/intern/idtype.c
@@ -209,7 +209,11 @@ uint64_t BKE_idtype_idcode_to_idfilter(const short idcode)
   case ID_##_id: \
     return FILTER_ID_##_id
 
-  switch (idcode) {
+#define CASE_IDFILTER_NONE(_id) \
+  case ID_##_id: \
+    return 0
+
+  switch ((ID_Type)idcode) {
     CASE_IDFILTER(AC);
     CASE_IDFILTER(AR);
     CASE_IDFILTER(BR);
@@ -220,7 +224,11 @@ uint64_t BKE_idtype_idcode_to_idfilter(const short idcode)
     CASE_IDFILTER(GR);
     CASE_IDFILTER(CV);
     CASE_IDFILTER(IM);
+    CASE_IDFILTER_NONE(IP);
+    CASE_IDFILTER(KE);
     CASE_IDFILTER(LA);
+    CASE_IDFILTER(LI);
+    CASE_IDFILTER(LP);
     CASE_IDFILTER(LS);
     CASE_IDFILTER(LT);
     CASE_IDFILTER(MA);
@@ -234,22 +242,25 @@ uint64_t BKE_idtype_idcode_to_idfilter(const short idcode)
     CASE_IDFILTER(PAL);
     CASE_IDFILTER(PC);
     CASE_IDFILTER(PT);
-    CASE_IDFILTER(LP);
     CASE_IDFILTER(SCE);
+    CASE_IDFILTER(SCR);
     CASE_IDFILTER(SIM);
-    CASE_IDFILTER(SPK);
     CASE_IDFILTER(SO);
+    CASE_IDFILTER(SPK);
     CASE_IDFILTER(TE);
     CASE_IDFILTER(TXT);
     CASE_IDFILTER(VF);
     CASE_IDFILTER(VO);
+    CASE_IDFILTER(WM);
     CASE_IDFILTER(WO);
     CASE_IDFILTER(WS);
-    default:
-      return 0;
   }
 
+  BLI_assert_unreachable();
+  return 0;
+
 #undef CASE_IDFILTER
+#undef CASE_IDFILTER_NONE
 }
 
 short BKE_idtype_idcode_from_idfilter(const uint64_t idfilter)
@@ -258,6 +269,8 @@ short BKE_idtype_idcode_from_idfilter(const uint64_t idfilter)
   case FILTER_ID_##_id: \
     return ID_##_id
 
+#define CASE_IDFILTER_NONE(_id) (void)0
+
   switch (idfilter) {
     CASE_IDFILTER(AC);
     CASE_IDFILTER(AR);
@@ -269,7 +282,11 @@ short BKE_idtype_idcode_from_idfilter(const uint64_t idfilter)
     CASE_IDFILTER(GR);
     CASE_IDFILTER(CV);
     CASE_IDFILTER(IM);
+    CASE_IDFILTER_NONE(IP);
+    CASE_IDFILTER(KE);
     CASE_IDFILTER(LA);
+    CASE_IDFILTER(LI);
+    CASE_IDFILTER(LP);
     CASE_IDFILTER(LS);
     CASE_IDFILTER(LT);
     CASE_IDFILTER(MA);
@@ -283,21 +300,25 @@ short BKE_idtype_idcode_from_idfilter(const uint64_t idfilter)
     CASE_IDFILTER(PAL);
     CASE_IDFILTER(PC);
     CASE_IDFILTER(PT);
-    CASE_IDFILTER(LP);
     CASE_IDFILTER(SCE);
+    CASE_IDFILTER(SCR);
     CASE_IDFILTER(SIM);
-    CASE_IDFILTER(SPK);
     CASE_IDFILTER(SO);
+    CASE_IDFILTER(SPK);
     CASE_IDFILTER(TE);
     CASE_IDFILTER(TXT);
     CASE_IDFILTER(VF);
     CASE_IDFILTER(VO);
+    CASE_IDFILTER(WM);
     CASE_IDFILTER(WO);
-    default:
-      return 0;
+    CASE_IDFILTER(WS);
   }
 
+  BLI_assert_unreachable();
+  return 0;
+
 #undef CASE_IDFILTER
+#undef CASE_IDFILTER_NONE
 }
 
 int BKE_idtype_idcode_to_index(const short idcode)
diff --git a/source/blender/blenkernel/intern/image.cc b/source/blender/blenkernel/intern/image.cc
index 92e98935e83..000e51c0150 100644
--- a/source/blender/blenkernel/intern/image.cc
+++ b/source/blender/blenkernel/intern/image.cc
@@ -442,7 +442,7 @@ constexpr IDTypeInfo get_type_info()
   info.foreach_id = nullptr;
   info.foreach_cache = image_foreach_cache;
   info.foreach_path = image_foreach_path;
-  info.owner_get = nullptr;
+  info.owner_pointer_get = nullptr;
 
   info.blend_write = image_blend_write;
   info.blend_read_data = image_blend_read_data;
@@ -627,6 +627,16 @@ void BKE_image_free_data(Image *ima)
   image_free_data(&ima->id);
 }
 
+static ImageTile *imagetile_alloc(int tile_number)
+{
+  ImageTile *tile = MEM_cnew("Image Tile");
+  tile->tile_number = tile_number;
+  tile->gen_x = 1024;
+  tile->gen_y = 1024;
+  tile->gen_type = IMA_GENTYPE_GRID;
+  return tile;
+}
+
 /* only image block itself */
 static void image_init(Image *ima, short source, short type)
 {
@@ -641,8 +651,7 @@ static void image_init(Image *ima, short source, short type)
     ima->flag |= IMA_VIEW_AS_RENDER;
   }
 
-  ImageTile *tile = MEM_cnew("Image Tiles");
-  tile->tile_number = 1001;
+  ImageTile *tile = imagetile_alloc(1001);
   BLI_addtail(&ima->tiles, tile);
 
   if (type == IMA_TYPE_R_RESULT) {
@@ -785,7 +794,7 @@ bool BKE_image_has_opengl_texture(Image *ima)
   return false;
 }
 
-static int image_get_tile_number_from_iuser(Image *ima, const ImageUser *iuser)
+static int image_get_tile_number_from_iuser(const Image *ima, const ImageUser *iuser)
 {
   BLI_assert(ima != nullptr && ima->tiles.first);
   ImageTile *tile = static_cast(ima->tiles.first);
@@ -863,33 +872,98 @@ void BKE_image_get_tile_uv(const Image *ima, const int tile_number, float r_uv[2
   }
 }
 
-int BKE_image_find_nearest_tile(const Image *image, const float co[2])
+/** Linear distance between #x and the unit interval. */
+static float distance_to_unit_interval(float x)
 {
-  const float co_floor[2] = {floorf(co[0]), floorf(co[1])};
-  /* Distance to the closest UDIM tile. */
-  float dist_best_sq = FLT_MAX;
+  /* The unit interval is between 0 and 1.
+   * Within the interval, return 0.
+   * Outside the interval, return the distance to the nearest boundary.
+   * Intuitively, the function looks like:
+   *  \ |   | /
+   * __\|___|/__
+   *    0   1
+   */
+
+  if (x <= 0.0f) {
+    return -x; /* Distance to left border. */
+  }
+  if (x <= 1.0f) {
+    return 0.0f; /* Inside unit interval. */
+  }
+  return x - 1.0f; /* Distance to right border. */
+}
+
+/** Distance squared between #co and the unit square with lower-left starting at #udim. */
+static float distance_squared_to_udim(const float co[2], const float udim[2])
+{
+  float delta[2];
+  sub_v2_v2v2(delta, co, udim);
+  delta[0] = distance_to_unit_interval(delta[0]);
+  delta[1] = distance_to_unit_interval(delta[1]);
+  return len_squared_v2(delta);
+}
+
+static bool nearest_udim_tile_tie_break(const float best_dist_sq,
+                                        const float best_uv[2],
+                                        const float dist_sq,
+                                        const float uv[2])
+{
+  if (best_dist_sq == dist_sq) {   /* Exact same distance? Tie-break. */
+    if (best_uv[0] == uv[0]) {     /* Exact same U? Tie-break. */
+      return (uv[1] > best_uv[1]); /* Higher than previous candidate? */
+    }
+    return (uv[0] > best_uv[0]); /* Further right than previous candidate? */
+  }
+  return (dist_sq < best_dist_sq); /* Closer than previous candidate? */
+}
+
+int BKE_image_find_nearest_tile_with_offset(const Image *image,
+                                            const float co[2],
+                                            float r_uv_offset[2])
+{
+  /* NOTE: If the co-ordinates are integers, take special care to break ties. */
+
+  zero_v2(r_uv_offset);
   int tile_number_best = -1;
 
+  if (!image || image->source != IMA_SRC_TILED) {
+    return tile_number_best;
+  }
+
+  /* Distance squared to the closest UDIM tile. */
+  float dist_best_sq = FLT_MAX;
+
   LISTBASE_FOREACH (const ImageTile *, tile, &image->tiles) {
     float uv_offset[2];
     BKE_image_get_tile_uv(image, tile->tile_number, uv_offset);
 
-    if (equals_v2v2(co_floor, uv_offset)) {
-      return tile->tile_number;
-    }
+    /* Distance squared between #co and closest point on UDIM tile. */
+    const float dist_sq = distance_squared_to_udim(co, uv_offset);
 
-    /* Distance between co[2] and UDIM tile. */
-    const float dist_sq = len_squared_v2v2(uv_offset, co);
+    if (dist_sq == 0) { /* Either inside in the UDIM, or on its boundary. */
+      if (floorf(co[0]) == uv_offset[0] && floorf(co[1]) == uv_offset[1]) {
+        /* Within the half-open interval of the UDIM. */
+        copy_v2_v2(r_uv_offset, uv_offset);
+        return tile_number_best;
+      }
+    }
 
-    if (dist_sq < dist_best_sq) {
+    if (nearest_udim_tile_tie_break(dist_best_sq, r_uv_offset, dist_sq, uv_offset)) {
+      /* Tile is better than previous best, update. */
       dist_best_sq = dist_sq;
+      copy_v2_v2(r_uv_offset, uv_offset);
       tile_number_best = tile->tile_number;
     }
   }
-
   return tile_number_best;
 }
 
+int BKE_image_find_nearest_tile(const struct Image *image, const float co[2])
+{
+  float uv_offset_dummy[2];
+  return BKE_image_find_nearest_tile_with_offset(image, co, uv_offset_dummy);
+}
+
 static void image_init_color_management(Image *ima)
 {
   ImBuf *ibuf;
@@ -897,7 +971,7 @@ static void image_init_color_management(Image *ima)
 
   BKE_image_user_file_path(nullptr, ima, name);
 
-  /* will set input color space to image format default's */
+  /* Will set input color space to image format default's. */
   ibuf = IMB_loadiffname(name, IB_test | IB_alphamode_detect, ima->colorspace_settings.name);
 
   if (ibuf) {
@@ -1035,73 +1109,70 @@ static void image_buf_fill_isolated(void *usersata_v)
   }
 }
 
-static ImBuf *add_ibuf_size(unsigned int width,
-                            unsigned int height,
-                            const char *name,
-                            int depth,
-                            int floatbuf,
-                            short gen_type,
-                            const float color[4],
-                            ColorManagedColorspaceSettings *colorspace_settings)
+static ImBuf *add_ibuf_for_tile(Image *ima, ImageTile *tile)
 {
   ImBuf *ibuf;
   unsigned char *rect = nullptr;
   float *rect_float = nullptr;
   float fill_color[4];
 
+  const bool floatbuf = (tile->gen_flag & IMA_GEN_FLOAT) != 0;
   if (floatbuf) {
-    ibuf = IMB_allocImBuf(width, height, depth, IB_rectfloat);
+    ibuf = IMB_allocImBuf(tile->gen_x, tile->gen_y, tile->gen_depth, IB_rectfloat);
 
-    if (colorspace_settings->name[0] == '\0') {
+    if (ima->colorspace_settings.name[0] == '\0') {
       const char *colorspace = IMB_colormanagement_role_colorspace_name_get(
           COLOR_ROLE_DEFAULT_FLOAT);
 
-      STRNCPY(colorspace_settings->name, colorspace);
+      STRNCPY(ima->colorspace_settings.name, colorspace);
     }
 
     if (ibuf != nullptr) {
       rect_float = ibuf->rect_float;
-      IMB_colormanagement_check_is_data(ibuf, colorspace_settings->name);
+      IMB_colormanagement_check_is_data(ibuf, ima->colorspace_settings.name);
     }
 
-    if (IMB_colormanagement_space_name_is_data(colorspace_settings->name)) {
-      copy_v4_v4(fill_color, color);
+    if (IMB_colormanagement_space_name_is_data(ima->colorspace_settings.name)) {
+      copy_v4_v4(fill_color, tile->gen_color);
     }
     else {
       /* The input color here should ideally be linear already, but for now
        * we just convert and postpone breaking the API for later. */
-      srgb_to_linearrgb_v4(fill_color, color);
+      srgb_to_linearrgb_v4(fill_color, tile->gen_color);
     }
   }
   else {
-    ibuf = IMB_allocImBuf(width, height, depth, IB_rect);
+    ibuf = IMB_allocImBuf(tile->gen_x, tile->gen_y, tile->gen_depth, IB_rect);
 
-    if (colorspace_settings->name[0] == '\0') {
+    if (ima->colorspace_settings.name[0] == '\0') {
       const char *colorspace = IMB_colormanagement_role_colorspace_name_get(
           COLOR_ROLE_DEFAULT_BYTE);
 
-      STRNCPY(colorspace_settings->name, colorspace);
+      STRNCPY(ima->colorspace_settings.name, colorspace);
     }
 
     if (ibuf != nullptr) {
       rect = (unsigned char *)ibuf->rect;
-      IMB_colormanagement_assign_rect_colorspace(ibuf, colorspace_settings->name);
+      IMB_colormanagement_assign_rect_colorspace(ibuf, ima->colorspace_settings.name);
     }
 
-    copy_v4_v4(fill_color, color);
+    copy_v4_v4(fill_color, tile->gen_color);
   }
 
   if (!ibuf) {
     return nullptr;
   }
 
-  STRNCPY(ibuf->name, name);
+  STRNCPY(ibuf->name, ima->filepath);
+
+  /* Mark the tile itself as having been generated. */
+  tile->gen_flag |= IMA_GEN_TILE;
 
   ImageFillData data;
 
-  data.gen_type = gen_type;
-  data.width = width;
-  data.height = height;
+  data.gen_type = tile->gen_type;
+  data.width = tile->gen_x;
+  data.height = tile->gen_y;
   data.rect = rect;
   data.rect_float = rect_float;
   copy_v4_v4(data.fill_color, fill_color);
@@ -1140,12 +1211,16 @@ Image *BKE_image_add_generated(Main *bmain,
 
   /* NOTE: leave `ima->filepath` unset,
    * setting it to a dummy value may write to an invalid file-path. */
-  ima->gen_x = width;
-  ima->gen_y = height;
-  ima->gen_type = gen_type;
-  ima->gen_flag |= (floatbuf ? IMA_GEN_FLOAT : 0);
-  ima->gen_depth = depth;
-  copy_v4_v4(ima->gen_color, color);
+
+  /* The generation info is always stored in the tiles. The first tile
+   * will be used for non-tiled images. */
+  ImageTile *tile = static_cast(ima->tiles.first);
+  tile->gen_x = width;
+  tile->gen_y = height;
+  tile->gen_type = gen_type;
+  tile->gen_flag |= (floatbuf ? IMA_GEN_FLOAT : 0);
+  tile->gen_depth = depth;
+  copy_v4_v4(tile->gen_color, color);
 
   if (is_data) {
     STRNCPY(ima->colorspace_settings.name,
@@ -1154,8 +1229,7 @@ Image *BKE_image_add_generated(Main *bmain,
 
   for (view_id = 0; view_id < 2; view_id++) {
     ImBuf *ibuf;
-    ibuf = add_ibuf_size(
-        width, height, ima->filepath, depth, floatbuf, gen_type, color, &ima->colorspace_settings);
+    ibuf = add_ibuf_for_tile(ima, tile);
     int index = tiled ? 0 : IMA_NO_INDEX;
     int entry = tiled ? 1001 : 0;
     image_assign_ibuf(ima, ibuf, stereo3d ? view_id : index, entry);
@@ -1174,7 +1248,7 @@ Image *BKE_image_add_generated(Main *bmain,
 
 static void image_colorspace_from_imbuf(Image *image, const ImBuf *ibuf)
 {
-  const char *colorspace_name = NULL;
+  const char *colorspace_name = nullptr;
 
   if (ibuf->rect_float) {
     if (ibuf->float_colorspace) {
@@ -2475,7 +2549,10 @@ int BKE_imbuf_write(ImBuf *ibuf, const char *name, const ImageFormatData *imf)
   return ok;
 }
 
-int BKE_imbuf_write_as(ImBuf *ibuf, const char *name, ImageFormatData *imf, const bool save_copy)
+int BKE_imbuf_write_as(ImBuf *ibuf,
+                       const char *name,
+                       const ImageFormatData *imf,
+                       const bool save_copy)
 {
   ImBuf ibuf_back = *ibuf;
   int ok;
@@ -2585,7 +2662,7 @@ Image *BKE_image_ensure_viewer(Main *bmain, int type, const char *name)
     ima = image_alloc(bmain, name, IMA_SRC_VIEWER, type);
   }
 
-  /* Happens on reload, imagewindow cannot be image user when hidden. */
+  /* Happens on reload, image-window cannot be image user when hidden. */
   if (ima->id.us == 0) {
     id_us_ensure_real(&ima->id);
   }
@@ -2933,6 +3010,28 @@ static void image_free_tile(Image *ima, ImageTile *tile)
   }
 }
 
+static bool image_remove_tile(Image *ima, ImageTile *tile)
+{
+  if (BLI_listbase_is_single(&ima->tiles)) {
+    /* Can't remove the last remaining tile. */
+    return false;
+  }
+
+  image_free_tile(ima, tile);
+  BLI_remlink(&ima->tiles, tile);
+  MEM_freeN(tile);
+
+  return true;
+}
+
+static void image_remove_all_tiles(Image *ima)
+{
+  /* Remove all but the final tile. */
+  while (image_remove_tile(ima, static_cast(ima->tiles.last))) {
+    ;
+  }
+}
+
 void BKE_image_signal(Main *bmain, Image *ima, ImageUser *iuser, int signal)
 {
   if (ima == nullptr) {
@@ -2959,11 +3058,12 @@ void BKE_image_signal(Main *bmain, Image *ima, ImageUser *iuser, int signal)
       }
 
       if (ima->source == IMA_SRC_GENERATED) {
-        if (ima->gen_x == 0 || ima->gen_y == 0) {
+        ImageTile *base_tile = BKE_image_get_tile(ima, 0);
+        if (base_tile->gen_x == 0 || base_tile->gen_y == 0) {
           ImBuf *ibuf = image_get_cached_ibuf_for_index_entry(ima, IMA_NO_INDEX, 0, nullptr);
           if (ibuf) {
-            ima->gen_x = ibuf->x;
-            ima->gen_y = ibuf->y;
+            base_tile->gen_x = ibuf->x;
+            base_tile->gen_y = ibuf->y;
             IMB_freeImBuf(ibuf);
           }
         }
@@ -2980,16 +3080,40 @@ void BKE_image_signal(Main *bmain, Image *ima, ImageUser *iuser, int signal)
 
       if (ima->source != IMA_SRC_TILED) {
         /* Free all but the first tile. */
+        image_remove_all_tiles(ima);
+
+        /* If the remaining tile is generated, we need to again ensure that we
+         * wouldn't continue to use the old filepath.
+         *
+         * Otherwise, if this used to be a UDIM image, get the concrete filepath associated
+         * with the remaining tile and use that as the new filepath. */
         ImageTile *base_tile = BKE_image_get_tile(ima, 0);
-        BLI_assert(base_tile == ima->tiles.first);
-        for (ImageTile *tile = base_tile->next, *tile_next; tile; tile = tile_next) {
-          tile_next = tile->next;
-          image_free_tile(ima, tile);
-          MEM_freeN(tile);
+        if ((base_tile->gen_flag & IMA_GEN_TILE) != 0) {
+          ima->filepath[0] = '\0';
+        }
+        else if (BKE_image_is_filename_tokenized(ima->filepath)) {
+          const bool was_relative = BLI_path_is_rel(ima->filepath);
+
+          eUDIM_TILE_FORMAT tile_format;
+          char *udim_pattern = BKE_image_get_tile_strformat(ima->filepath, &tile_format);
+          BKE_image_set_filepath_from_tile_number(
+              ima->filepath, udim_pattern, tile_format, base_tile->tile_number);
+          MEM_freeN(udim_pattern);
+
+          if (was_relative) {
+            const char *relbase = ID_BLEND_PATH(bmain, &ima->id);
+            BLI_path_rel(ima->filepath, relbase);
+          }
         }
-        base_tile->next = nullptr;
+
+        /* If the remaining tile was not number 1001, we need to reassign it so that
+         * ibuf lookups from the cache still succeed. */
         base_tile->tile_number = 1001;
-        ima->tiles.last = base_tile;
+      }
+      else {
+        /* When changing to UDIM, attempt to tokenize the filepath. */
+        char *filename = (char *)BLI_path_basename(ima->filepath);
+        BKE_image_ensure_tile_token(filename);
       }
 
       /* image buffers for non-sequence multilayer will share buffers with RenderResult,
@@ -3005,6 +3129,7 @@ void BKE_image_signal(Main *bmain, Image *ima, ImageUser *iuser, int signal)
         image_tag_frame_recalc(ima, nullptr, iuser, ima);
       }
       BKE_image_walk_all_users(bmain, ima, image_tag_frame_recalc);
+      BKE_image_partial_update_mark_full_update(ima);
 
       break;
 
@@ -3056,9 +3181,7 @@ void BKE_image_signal(Main *bmain, Image *ima, ImageUser *iuser, int signal)
            * to account for how the two sets might or might not overlap. To be complete, we start
            * the refresh process by clearing all existing tiles, stopping when there's only 1 tile
            * left. */
-          while (BKE_image_remove_tile(ima, static_cast(ima->tiles.last))) {
-            ;
-          }
+          image_remove_all_tiles(ima);
 
           int remaining_tile_number = ((ImageTile *)ima->tiles.first)->tile_number;
           bool needs_final_cleanup = true;
@@ -3241,8 +3364,7 @@ ImageTile *BKE_image_add_tile(struct Image *ima, int tile_number, const char *la
     }
   }
 
-  ImageTile *tile = MEM_cnew("image new tile");
-  tile->tile_number = tile_number;
+  ImageTile *tile = imagetile_alloc(tile_number);
 
   if (next_tile) {
     BLI_insertlinkbefore(&ima->tiles, next_tile, tile);
@@ -3277,16 +3399,7 @@ bool BKE_image_remove_tile(struct Image *ima, ImageTile *tile)
     return false;
   }
 
-  if (BLI_listbase_is_single(&ima->tiles)) {
-    /* Can't remove the last remaining tile. */
-    return false;
-  }
-
-  image_free_tile(ima, tile);
-  BLI_remlink(&ima->tiles, tile);
-  MEM_freeN(tile);
-
-  return true;
+  return image_remove_tile(ima, tile);
 }
 
 void BKE_image_reassign_tile(struct Image *ima, ImageTile *tile, int new_tile_number)
@@ -3348,14 +3461,7 @@ void BKE_image_sort_tiles(struct Image *ima)
   BLI_listbase_sort(&ima->tiles, tile_sort_cb);
 }
 
-bool BKE_image_fill_tile(struct Image *ima,
-                         ImageTile *tile,
-                         int width,
-                         int height,
-                         const float color[4],
-                         int gen_type,
-                         int planes,
-                         bool is_float)
+bool BKE_image_fill_tile(struct Image *ima, ImageTile *tile)
 {
   if (ima == nullptr || tile == nullptr || ima->source != IMA_SRC_TILED) {
     return false;
@@ -3363,8 +3469,7 @@ bool BKE_image_fill_tile(struct Image *ima,
 
   image_free_tile(ima, tile);
 
-  ImBuf *tile_ibuf = add_ibuf_size(
-      width, height, ima->filepath, planes, is_float, gen_type, color, &ima->colorspace_settings);
+  ImBuf *tile_ibuf = add_ibuf_for_tile(ima, tile);
 
   if (tile_ibuf != nullptr) {
     image_assign_ibuf(ima, tile_ibuf, 0, tile->tile_number);
@@ -3394,9 +3499,8 @@ void BKE_image_ensure_tile_token(char *filename)
 
   /* General 4-digit "udim" pattern. As this format is susceptible to ambiguity
    * with other digit sequences, we can leverage the supported range of roughly
-   * 1000 through 2000 to provide better detection.
-   */
-  std::regex pattern(R"((^|.*?\D)([12]\d{3})(\D.*))");
+   * 1000 through 2000 to provide better detection. */
+  std::regex pattern(R"((.*[._-])([12]\d{3})([._-].*))");
   if (std::regex_search(path, match, pattern)) {
     BLI_strncpy(filename, match.format("$1$3").c_str(), FILE_MAX);
     return;
@@ -3547,7 +3651,7 @@ RenderPass *BKE_image_multilayer_index(RenderResult *rr, ImageUser *iuser)
   return rpass;
 }
 
-void BKE_image_multiview_index(Image *ima, ImageUser *iuser)
+void BKE_image_multiview_index(const Image *ima, ImageUser *iuser)
 {
   if (iuser) {
     bool is_stereo = BKE_image_is_stereo(ima) && (iuser->flag & IMA_SHOW_STEREO);
@@ -3568,7 +3672,7 @@ void BKE_image_multiview_index(Image *ima, ImageUser *iuser)
 
 /* if layer or pass changes, we need an index for the imbufs list */
 /* note it is called for rendered results, but it doesn't use the index! */
-bool BKE_image_is_multilayer(Image *ima)
+bool BKE_image_is_multilayer(const Image *ima)
 {
   if (ELEM(ima->source, IMA_SRC_FILE, IMA_SRC_SEQUENCE, IMA_SRC_TILED)) {
     if (ima->type == IMA_TYPE_MULTILAYER) {
@@ -3583,13 +3687,13 @@ bool BKE_image_is_multilayer(Image *ima)
   return false;
 }
 
-bool BKE_image_is_multiview(Image *ima)
+bool BKE_image_is_multiview(const Image *ima)
 {
   ImageView *view = static_cast(ima->views.first);
   return (view && (view->next || view->name[0]));
 }
 
-bool BKE_image_is_stereo(Image *ima)
+bool BKE_image_is_stereo(const Image *ima)
 {
   return BKE_image_is_multiview(ima) &&
          (BLI_findstring(&ima->views, STEREO_LEFT_NAME, offsetof(ImageView, name)) &&
@@ -4538,14 +4642,22 @@ static ImBuf *image_acquire_ibuf(Image *ima, ImageUser *iuser, void **r_lock)
       }
     }
     else if (ima->source == IMA_SRC_TILED) {
-      if (ima->type == IMA_TYPE_IMAGE) {
-        /* Regular files, ibufs in flip-book, allows saving */
-        ibuf = image_load_image_file(ima, iuser, entry, 0, false);
+      /* Nothing was cached. Check to see if the tile should be generated. */
+      ImageTile *tile = BKE_image_get_tile(ima, entry);
+      if ((tile->gen_flag & IMA_GEN_TILE) != 0) {
+        ibuf = add_ibuf_for_tile(ima, tile);
+        image_assign_ibuf(ima, ibuf, 0, entry);
       }
-      /* no else; on load the ima type can change */
-      if (ima->type == IMA_TYPE_MULTILAYER) {
-        /* Only 1 layer/pass stored in imbufs, no EXR-handle anim storage, no saving. */
-        ibuf = image_load_sequence_multilayer(ima, iuser, entry, 0);
+      else {
+        if (ima->type == IMA_TYPE_IMAGE) {
+          /* Regular files, ibufs in flip-book, allows saving */
+          ibuf = image_load_image_file(ima, iuser, entry, 0, false);
+        }
+        /* no else; on load the ima type can change */
+        if (ima->type == IMA_TYPE_MULTILAYER) {
+          /* Only 1 layer/pass stored in imbufs, no EXR-handle anim storage, no saving. */
+          ibuf = image_load_sequence_multilayer(ima, iuser, entry, 0);
+        }
       }
     }
     else if (ima->source == IMA_SRC_FILE) {
@@ -4563,23 +4675,17 @@ static ImBuf *image_acquire_ibuf(Image *ima, ImageUser *iuser, void **r_lock)
     else if (ima->source == IMA_SRC_GENERATED) {
       /* Generated is: `ibuf` is allocated dynamically. */
       /* UV test-grid or black or solid etc. */
-      if (ima->gen_x == 0) {
-        ima->gen_x = 1024;
+      ImageTile *base_tile = BKE_image_get_tile(ima, 0);
+      if (base_tile->gen_x == 0) {
+        base_tile->gen_x = 1024;
       }
-      if (ima->gen_y == 0) {
-        ima->gen_y = 1024;
+      if (base_tile->gen_y == 0) {
+        base_tile->gen_y = 1024;
       }
-      if (ima->gen_depth == 0) {
-        ima->gen_depth = 24;
+      if (base_tile->gen_depth == 0) {
+        base_tile->gen_depth = 24;
       }
-      ibuf = add_ibuf_size(ima->gen_x,
-                           ima->gen_y,
-                           ima->filepath,
-                           ima->gen_depth,
-                           (ima->gen_flag & IMA_GEN_FLOAT) != 0,
-                           ima->gen_type,
-                           ima->gen_color,
-                           &ima->colorspace_settings);
+      ibuf = add_ibuf_for_tile(ima, base_tile);
       image_assign_ibuf(ima, ibuf, index, 0);
     }
     else if (ima->source == IMA_SRC_VIEWER) {
@@ -4922,10 +5028,12 @@ static void image_editors_update_frame(Image *ima,
                                        ImageUser *iuser,
                                        void *customdata)
 {
-  int cfra = *(int *)customdata;
+  if (ima && BKE_image_is_animated(ima)) {
+    if ((iuser->flag & IMA_ANIM_ALWAYS) || (iuser->flag & IMA_NEED_FRAME_RECALC)) {
+      int cfra = *(int *)customdata;
 
-  if ((iuser->flag & IMA_ANIM_ALWAYS) || (iuser->flag & IMA_NEED_FRAME_RECALC)) {
-    BKE_image_user_frame_calc(ima, iuser, cfra);
+      BKE_image_user_frame_calc(ima, iuser, cfra);
+    }
   }
 }
 
@@ -4985,14 +5093,19 @@ void BKE_image_user_id_eval_animation(Depsgraph *depsgraph, ID *id)
   image_walk_id_all_users(id, skip_nested_nodes, depsgraph, image_user_id_eval_animation);
 }
 
-void BKE_image_user_file_path(ImageUser *iuser, Image *ima, char *filepath)
+void BKE_image_user_file_path(const ImageUser *iuser, const Image *ima, char *filepath)
 {
-  BKE_image_user_file_path_ex(iuser, ima, filepath, true);
+  BKE_image_user_file_path_ex(G_MAIN, iuser, ima, filepath, true, true);
 }
 
-void BKE_image_user_file_path_ex(ImageUser *iuser, Image *ima, char *filepath, bool resolve_udim)
+void BKE_image_user_file_path_ex(const Main *bmain,
+                                 const ImageUser *iuser,
+                                 const Image *ima,
+                                 char *filepath,
+                                 const bool resolve_udim,
+                                 const bool resolve_multiview)
 {
-  if (BKE_image_is_multiview(ima)) {
+  if (resolve_multiview && BKE_image_is_multiview(ima)) {
     ImageView *iv = static_cast(BLI_findlink(&ima->views, iuser->view));
     if (iv->filepath[0]) {
       BLI_strncpy(filepath, iv->filepath, FILE_MAX);
@@ -5025,7 +5138,7 @@ void BKE_image_user_file_path_ex(ImageUser *iuser, Image *ima, char *filepath, b
     }
   }
 
-  BLI_path_abs(filepath, ID_BLEND_PATH_FROM_GLOBAL(&ima->id));
+  BLI_path_abs(filepath, ID_BLEND_PATH(bmain, &ima->id));
 }
 
 bool BKE_image_has_alpha(Image *image)
@@ -5057,13 +5170,7 @@ void BKE_image_get_size(Image *image, ImageUser *iuser, int *r_width, int *r_hei
   }
   else if (image != nullptr && image->type == IMA_TYPE_R_RESULT && iuser != nullptr &&
            iuser->scene != nullptr) {
-    Scene *scene = iuser->scene;
-    *r_width = (scene->r.xsch * scene->r.size) / 100;
-    *r_height = (scene->r.ysch * scene->r.size) / 100;
-    if ((scene->r.mode & R_BORDER) && (scene->r.mode & R_CROP)) {
-      *r_width *= BLI_rctf_size_x(&scene->r.border);
-      *r_height *= BLI_rctf_size_y(&scene->r.border);
-    }
+    BKE_render_resolution(&iuser->scene->r, true, r_width, r_height);
   }
   else {
     *r_width = IMG_SIZE_FALLBACK;
@@ -5412,7 +5519,7 @@ RenderSlot *BKE_image_add_renderslot(Image *ima, const char *name)
   }
   else {
     int n = BLI_listbase_count(&ima->renderslots) + 1;
-    BLI_snprintf(slot->name, sizeof(slot->name), "Slot %d", n);
+    BLI_snprintf(slot->name, sizeof(slot->name), DATA_("Slot %d"), n);
   }
   BLI_addtail(&ima->renderslots, slot);
   return slot;
@@ -5460,15 +5567,14 @@ bool BKE_image_remove_renderslot(Image *ima, ImageUser *iuser, int slot)
       next_last_slot = current_slot;
     }
 
-    if (!iuser) {
+    if (iuser == nullptr || iuser->scene == nullptr) {
       return false;
     }
     Render *re = RE_GetSceneRender(iuser->scene);
-    if (!re) {
-      return false;
+    if (re != nullptr) {
+      RE_SwapResult(re, ¤t_last_slot->render);
+      RE_SwapResult(re, &next_last_slot->render);
     }
-    RE_SwapResult(re, ¤t_last_slot->render);
-    RE_SwapResult(re, &next_last_slot->render);
     current_last_slot = next_last_slot;
   }
 
@@ -5505,7 +5611,7 @@ bool BKE_image_clear_renderslot(Image *ima, ImageUser *iuser, int slot)
   }
 
   RenderSlot *render_slot = static_cast(BLI_findlink(&ima->renderslots, slot));
-  if (!slot) {
+  if (!render_slot) {
     return false;
   }
   if (render_slot->render) {
diff --git a/source/blender/blenkernel/intern/image_gpu.cc b/source/blender/blenkernel/intern/image_gpu.cc
index 6edb9e1b24c..08fdd715512 100644
--- a/source/blender/blenkernel/intern/image_gpu.cc
+++ b/source/blender/blenkernel/intern/image_gpu.cc
@@ -138,6 +138,8 @@ static GPUTexture *gpu_texture_create_tile_array(Image *ima, ImBuf *main_ibuf)
   int arraywidth = 0, arrayheight = 0;
   ListBase boxes = {nullptr};
 
+  int planes = 0;
+
   LISTBASE_FOREACH (ImageTile *, tile, &ima->tiles) {
     ImageUser iuser;
     BKE_imageuser_default(&iuser);
@@ -164,6 +166,7 @@ static GPUTexture *gpu_texture_create_tile_array(Image *ima, ImBuf *main_ibuf)
 
       BKE_image_release_ibuf(ima, ibuf, nullptr);
       BLI_addtail(&boxes, packtile);
+      planes = max_ii(planes, ibuf->planes);
     }
   }
 
@@ -195,9 +198,15 @@ static GPUTexture *gpu_texture_create_tile_array(Image *ima, ImBuf *main_ibuf)
   }
 
   const bool use_high_bitdepth = (ima->flag & IMA_HIGH_BITDEPTH);
+  const bool use_grayscale = planes <= 8;
   /* Create Texture without content. */
-  GPUTexture *tex = IMB_touch_gpu_texture(
-      ima->id.name + 2, main_ibuf, arraywidth, arrayheight, arraylayers, use_high_bitdepth);
+  GPUTexture *tex = IMB_touch_gpu_texture(ima->id.name + 2,
+                                          main_ibuf,
+                                          arraywidth,
+                                          arrayheight,
+                                          arraylayers,
+                                          use_high_bitdepth,
+                                          use_grayscale);
 
   /* Upload each tile one by one. */
   LISTBASE_FOREACH (ImageTile *, tile, &ima->tiles) {
@@ -223,6 +232,7 @@ static GPUTexture *gpu_texture_create_tile_array(Image *ima, ImBuf *main_ibuf)
                                  tilelayer,
                                  UNPACK2(tilesize),
                                  use_high_bitdepth,
+                                 use_grayscale,
                                  store_premultiplied);
     }
 
@@ -737,11 +747,11 @@ static void gpu_texture_update_from_ibuf(
   }
   else {
     /* Byte image is in original colorspace from the file, and may need conversion. */
-    if (IMB_colormanagement_space_is_data(ibuf->rect_colorspace) ||
-        IMB_colormanagement_space_is_scene_linear(ibuf->rect_colorspace)) {
+    if (IMB_colormanagement_space_is_data(ibuf->rect_colorspace)) {
       /* Non-color data, just store buffer as is. */
     }
-    else if (IMB_colormanagement_space_is_srgb(ibuf->rect_colorspace)) {
+    else if (IMB_colormanagement_space_is_srgb(ibuf->rect_colorspace) ||
+             IMB_colormanagement_space_is_scene_linear(ibuf->rect_colorspace)) {
       /* sRGB or scene linear, store as byte texture that the GPU can decode directly. */
       rect = (uchar *)MEM_mallocN(sizeof(uchar[4]) * w * h, __func__);
       if (rect == nullptr) {
diff --git a/source/blender/blenkernel/intern/image_partial_update.cc b/source/blender/blenkernel/intern/image_partial_update.cc
index c77ee77a5f2..6ffd323cc1e 100644
--- a/source/blender/blenkernel/intern/image_partial_update.cc
+++ b/source/blender/blenkernel/intern/image_partial_update.cc
@@ -413,7 +413,7 @@ struct PartialUpdateRegisterImpl {
   }
 
   /**
-   * /brief Check if data is available to construct the update tiles for the given
+   * \brief Check if data is available to construct the update tiles for the given
    * changeset_id.
    *
    * The update tiles can be created when changeset id is between
diff --git a/source/blender/blenkernel/intern/image_save.cc b/source/blender/blenkernel/intern/image_save.cc
index 3f6f81845e2..6f62ee123cb 100644
--- a/source/blender/blenkernel/intern/image_save.cc
+++ b/source/blender/blenkernel/intern/image_save.cc
@@ -13,6 +13,8 @@
 #include "BLI_string.h"
 #include "BLI_vector.hh"
 
+#include "BLT_translation.h"
+
 #include "DNA_image_types.h"
 
 #include "MEM_guardedalloc.h"
@@ -144,13 +146,9 @@ bool BKE_image_save_options_init(ImageSaveOptions *opts,
 
     opts->im_format.color_management = R_IMF_COLOR_MANAGEMENT_FOLLOW_SCENE;
 
-    if (ibuf->name[0] == '\0' || ima->source == IMA_SRC_TILED) {
-      BLI_strncpy(opts->filepath, ima->filepath, sizeof(opts->filepath));
-      BLI_path_abs(opts->filepath, ID_BLEND_PATH_FROM_GLOBAL(&ima->id));
-    }
-    else {
-      BLI_strncpy(opts->filepath, ibuf->name, sizeof(opts->filepath));
-    }
+    /* Compute filepath, but don't resolve multiview and UDIM which are handled
+     * by the image saving code itself. */
+    BKE_image_user_file_path_ex(bmain, iuser, ima, opts->filepath, false, false);
 
     /* sanitize all settings */
 
@@ -177,12 +175,12 @@ bool BKE_image_save_options_init(ImageSaveOptions *opts,
           BLI_strncpy(opts->filepath, G.ima, sizeof(opts->filepath));
         }
         else {
-          BLI_strncpy(opts->filepath, "//untitled", sizeof(opts->filepath));
+          BLI_path_join(opts->filepath, sizeof(opts->filepath), "//", DATA_("untitled"), nullptr);
           BLI_path_abs(opts->filepath, BKE_main_blendfile_path(bmain));
         }
       }
       else {
-        BLI_snprintf(opts->filepath, sizeof(opts->filepath), "//%s", ima->id.name + 2);
+        BLI_path_join(opts->filepath, sizeof(opts->filepath), "//", ima->id.name + 2, nullptr);
         BLI_path_make_safe(opts->filepath);
         BLI_path_abs(opts->filepath, is_prev_save ? G.ima : BKE_main_blendfile_path(bmain));
       }
@@ -204,7 +202,7 @@ bool BKE_image_save_options_init(ImageSaveOptions *opts,
   return (ibuf != nullptr);
 }
 
-void BKE_image_save_options_update(ImageSaveOptions *opts, Image *image)
+void BKE_image_save_options_update(ImageSaveOptions *opts, const Image *image)
 {
   /* Auto update color space when changing save as render and file type. */
   if (opts->save_as_render) {
@@ -272,7 +270,7 @@ static void image_save_post(ReportList *reports,
                             Image *ima,
                             ImBuf *ibuf,
                             int ok,
-                            ImageSaveOptions *opts,
+                            const ImageSaveOptions *opts,
                             int save_copy,
                             const char *filepath,
                             bool *r_colorspace_changed)
@@ -320,6 +318,8 @@ static void image_save_post(ReportList *reports,
   if (ELEM(ima->source, IMA_SRC_GENERATED, IMA_SRC_VIEWER)) {
     ima->source = IMA_SRC_FILE;
     ima->type = IMA_TYPE_IMAGE;
+    ImageTile *base_tile = BKE_image_get_tile(ima, 0);
+    base_tile->gen_flag &= ~IMA_GEN_TILE;
   }
 
   /* Update image file color space when saving to another color space. */
@@ -359,7 +359,7 @@ static void imbuf_save_post(ImBuf *ibuf, ImBuf *colormanaged_ibuf)
 static bool image_save_single(ReportList *reports,
                               Image *ima,
                               ImageUser *iuser,
-                              ImageSaveOptions *opts,
+                              const ImageSaveOptions *opts,
                               bool *r_colorspace_changed)
 {
   void *lock;
@@ -375,7 +375,7 @@ static bool image_save_single(ReportList *reports,
   ImBuf *colormanaged_ibuf = nullptr;
   const bool save_copy = opts->save_copy;
   const bool save_as_render = opts->save_as_render;
-  ImageFormatData *imf = &opts->im_format;
+  const ImageFormatData *imf = &opts->im_format;
 
   if (ima->type == IMA_TYPE_R_RESULT) {
     /* enforce user setting for RGB or RGBA, but skip BW */
@@ -620,7 +620,7 @@ static bool image_save_single(ReportList *reports,
 }
 
 bool BKE_image_save(
-    ReportList *reports, Main *bmain, Image *ima, ImageUser *iuser, ImageSaveOptions *opts)
+    ReportList *reports, Main *bmain, Image *ima, ImageUser *iuser, const ImageSaveOptions *opts)
 {
   /* For saving a tiled image we need an iuser, so use a local one if there isn't already one. */
   ImageUser save_iuser;
@@ -666,8 +666,11 @@ bool BKE_image_save(
       }
     }
 
-    /* Set the image path only if all tiles were ok. */
+    /* Set the image path and clear the per-tile generated flag only if all tiles were ok. */
     if (ok) {
+      LISTBASE_FOREACH (ImageTile *, tile, &ima->tiles) {
+        tile->gen_flag &= ~IMA_GEN_TILE;
+      }
       image_save_update_filepath(ima, opts->filepath, opts);
     }
     MEM_freeN(udim_pattern);
@@ -820,7 +823,7 @@ bool BKE_image_render_write_exr(ReportList *reports,
       const bool pass_RGBA = (STR_ELEM(rp->chan_id, "RGB", "RGBA", "R", "G", "B", "A"));
       const bool pass_half_float = half_float && pass_RGBA;
 
-      /* Colorspace conversion only happens on RGBA passes. */
+      /* Color-space conversion only happens on RGBA passes. */
       float *output_rect =
           (save_as_render && pass_RGBA) ?
               image_exr_from_scene_linear_to_output(
diff --git a/source/blender/blenkernel/intern/image_test.cc b/source/blender/blenkernel/intern/image_test.cc
index 9c15fc62d21..7004d39c805 100644
--- a/source/blender/blenkernel/intern/image_test.cc
+++ b/source/blender/blenkernel/intern/image_test.cc
@@ -32,8 +32,12 @@ TEST(udim, image_ensure_tile_token)
   verify("test_1002_ao.png", "test__ao.png");
   verify("test.1002.ver0023.png", "test..ver0023.png");
   verify("test.ver0023.1002.png", "test.ver0023..png");
-  verify("1002test.png", "test.png");
-  verify("test1002.png", "test.png");
+  verify("test.1002.1.png", "test..1.png");
+  verify("test.1.1002.png", "test.1..png");
+  verify("test-2022-01-01.1002.png", "test-2022-01-01..png");
+  verify("1111_11.1002.png", "1111_11..png");
+  verify("2111_01.1002.png", "2111_01..png");
+  verify("2022_1002_100200.1002.png", "2022_1002_100200..png");
 
   /* UVTILE pattern detection. */
   verify("uv-test.u2_v10.png", "uv-test..png");
@@ -44,8 +48,15 @@ TEST(udim, image_ensure_tile_token)
   verify("u2_v10uv-test.png", "uv-test.png");
   verify("u2_v10u_v-test.png", "u_v-test.png");
 
-  /* Incorrect patterns. */
-  for (const char *incorrect : {"test.123.png",
+  /* Patterns which should not be detected as UDIMs. */
+  for (const char *incorrect : {"1002.png",
+                                "1002test.png",
+                                "test1002.png",
+                                "test(1002).png",
+                                "(1002)test.png",
+                                "test-1080p.png",
+                                "test-1920x1080.png",
+                                "test.123.png",
                                 "test.12345.png",
                                 "test.uv.png",
                                 "test.u1v.png",
diff --git a/source/blender/blenkernel/intern/ipo.c b/source/blender/blenkernel/intern/ipo.c
index abd6505456e..40a5c08a068 100644
--- a/source/blender/blenkernel/intern/ipo.c
+++ b/source/blender/blenkernel/intern/ipo.c
@@ -178,7 +178,7 @@ IDTypeInfo IDType_ID_IP = {
     .foreach_id = NULL,
     .foreach_cache = NULL,
     .foreach_path = NULL,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = NULL,
     .blend_read_data = ipo_blend_read_data,
@@ -2142,7 +2142,7 @@ void do_versions_ipos_to_animato(Main *bmain)
       if (ob->action) {
         action_to_animdata(id, ob->action);
 
-        /* only decrease usercount if this Action isn't now being used by AnimData */
+        /* Only decrease user-count if this Action isn't now being used by AnimData. */
         if (ob->action != adt->action) {
           id_us_min(&ob->action->id);
           ob->action = NULL;
@@ -2246,7 +2246,7 @@ void do_versions_ipos_to_animato(Main *bmain)
       /* Add AnimData block */
       AnimData *adt = BKE_animdata_ensure_id(id);
 
-      /* Convert Shapekey data... */
+      /* Convert Shape-key data... */
       ipo_to_animdata(bmain, id, key->ipo, NULL, NULL, NULL);
 
       if (adt->action) {
diff --git a/source/blender/blenkernel/intern/key.c b/source/blender/blenkernel/intern/key.c
index 594cffe6406..2ba81c54872 100644
--- a/source/blender/blenkernel/intern/key.c
+++ b/source/blender/blenkernel/intern/key.c
@@ -46,6 +46,7 @@
 #include "BKE_scene.h"
 
 #include "RNA_access.h"
+#include "RNA_path.h"
 #include "RNA_prototypes.h"
 
 #include "BLO_read_write.h"
@@ -90,9 +91,14 @@ static void shapekey_foreach_id(ID *id, LibraryForeachIDData *data)
   BKE_LIB_FOREACHID_PROCESS_ID(data, key->from, IDWALK_CB_LOOPBACK);
 }
 
-static ID *shapekey_owner_get(Main *UNUSED(bmain), ID *id)
+static ID **shapekey_owner_pointer_get(ID *id)
 {
-  return ((Key *)id)->from;
+  Key *key = (Key *)id;
+
+  BLI_assert(key->from != NULL);
+  BLI_assert(BKE_key_from_id(key->from) == key);
+
+  return &key->from;
 }
 
 static void shapekey_blend_write(BlendWriter *writer, ID *id, const void *id_address)
@@ -191,7 +197,7 @@ static void shapekey_blend_read_expand(BlendExpander *expander, ID *id)
 
 IDTypeInfo IDType_ID_KE = {
     .id_code = ID_KE,
-    .id_filter = 0,
+    .id_filter = FILTER_ID_KE,
     .main_listbase_index = INDEX_ID_KE,
     .struct_size = sizeof(Key),
     .name = "Key",
@@ -209,7 +215,7 @@ IDTypeInfo IDType_ID_KE = {
     .foreach_path = NULL,
     /* A bit weird, due to shape-keys not being strictly speaking embedded data... But they also
      * share a lot with those (non linkable, only ever used by one owner ID, etc.). */
-    .owner_get = shapekey_owner_get,
+    .owner_pointer_get = shapekey_owner_pointer_get,
 
     .blend_write = shapekey_blend_write,
     .blend_read_data = shapekey_blend_read_data,
@@ -1257,7 +1263,7 @@ static void do_key(const int start,
 
 static float *get_weights_array(Object *ob, char *vgroup, WeightsArrayCache *cache)
 {
-  MDeformVert *dvert = NULL;
+  const MDeformVert *dvert = NULL;
   BMEditMesh *em = NULL;
   BMIter iter;
   BMVert *eve;
@@ -1271,7 +1277,7 @@ static float *get_weights_array(Object *ob, char *vgroup, WeightsArrayCache *cac
   /* gather dvert and totvert */
   if (ob->type == OB_MESH) {
     Mesh *me = ob->data;
-    dvert = me->dvert;
+    dvert = BKE_mesh_deform_verts(me);
     totvert = me->totvert;
 
     if (me->edit_mesh && me->edit_mesh->bm->totvert == totvert) {
@@ -1501,7 +1507,14 @@ static void do_latt_key(Object *ob, Key *key, char *out, const int tot)
   }
 }
 
-float *BKE_key_evaluate_object_ex(Object *ob, int *r_totelem, float *arr, size_t arr_size)
+static void keyblock_data_convert_to_mesh(const float (*fp)[3], MVert *mvert, const int totvert);
+static void keyblock_data_convert_to_lattice(const float (*fp)[3],
+                                             BPoint *bpoint,
+                                             const int totpoint);
+static void keyblock_data_convert_to_curve(const float *fp, ListBase *nurb, const int totpoint);
+
+float *BKE_key_evaluate_object_ex(
+    Object *ob, int *r_totelem, float *arr, size_t arr_size, ID *obdata)
 {
   Key *key = BKE_key_from_object(ob);
   KeyBlock *actkb = BKE_keyblock_from_object(ob);
@@ -1576,7 +1589,6 @@ float *BKE_key_evaluate_object_ex(Object *ob, int *r_totelem, float *arr, size_t
     }
   }
   else {
-
     if (ob->type == OB_MESH) {
       do_mesh_key(ob, key, out, tot);
     }
@@ -1591,6 +1603,32 @@ float *BKE_key_evaluate_object_ex(Object *ob, int *r_totelem, float *arr, size_t
     }
   }
 
+  if (obdata != NULL) {
+    switch (GS(obdata->name)) {
+      case ID_ME: {
+        Mesh *mesh = (Mesh *)obdata;
+        MVert *verts = BKE_mesh_verts_for_write(mesh);
+        const int totvert = min_ii(tot, mesh->totvert);
+        keyblock_data_convert_to_mesh((const float(*)[3])out, verts, totvert);
+        break;
+      }
+      case ID_LT: {
+        Lattice *lattice = (Lattice *)obdata;
+        const int totpoint = min_ii(tot, lattice->pntsu * lattice->pntsv * lattice->pntsw);
+        keyblock_data_convert_to_lattice((const float(*)[3])out, lattice->def, totpoint);
+        break;
+      }
+      case ID_CU_LEGACY: {
+        Curve *curve = (Curve *)obdata;
+        const int totpoint = min_ii(tot, BKE_keyblock_curve_element_count(&curve->nurb));
+        keyblock_data_convert_to_curve((const float *)out, &curve->nurb, totpoint);
+        break;
+      }
+      default:
+        BLI_assert_unreachable();
+    }
+  }
+
   if (r_totelem) {
     *r_totelem = tot;
   }
@@ -1599,7 +1637,7 @@ float *BKE_key_evaluate_object_ex(Object *ob, int *r_totelem, float *arr, size_t
 
 float *BKE_key_evaluate_object(Object *ob, int *r_totelem)
 {
-  return BKE_key_evaluate_object_ex(ob, r_totelem, NULL, 0);
+  return BKE_key_evaluate_object_ex(ob, r_totelem, NULL, 0, NULL);
 }
 
 int BKE_keyblock_element_count_from_shape(const Key *key, const int shape_index)
@@ -1900,6 +1938,16 @@ KeyBlock *BKE_keyblock_find_name(Key *key, const char name[])
   return BLI_findstring(&key->block, name, offsetof(KeyBlock, name));
 }
 
+KeyBlock *BKE_keyblock_find_uid(Key *key, const int uid)
+{
+  LISTBASE_FOREACH (KeyBlock *, kb, &key->block) {
+    if (kb->uid == uid) {
+      return kb;
+    }
+  }
+  return NULL;
+}
+
 void BKE_keyblock_copy_settings(KeyBlock *kb_dst, const KeyBlock *kb_src)
 {
   kb_dst->pos = kb_src->pos;
@@ -1971,21 +2019,22 @@ void BKE_keyblock_convert_from_lattice(const Lattice *lt, KeyBlock *kb)
   BKE_keyblock_update_from_lattice(lt, kb);
 }
 
-void BKE_keyblock_convert_to_lattice(const KeyBlock *kb, Lattice *lt)
+static void keyblock_data_convert_to_lattice(const float (*fp)[3],
+                                             BPoint *bpoint,
+                                             const int totpoint)
 {
-  BPoint *bp;
-  const float(*fp)[3];
-  int a, tot;
-
-  bp = lt->def;
-  fp = kb->data;
+  for (int i = 0; i < totpoint; i++, fp++, bpoint++) {
+    copy_v3_v3(bpoint->vec, *fp);
+  }
+}
 
-  tot = lt->pntsu * lt->pntsv * lt->pntsw;
-  tot = min_ii(kb->totelem, tot);
+void BKE_keyblock_convert_to_lattice(const KeyBlock *kb, Lattice *lt)
+{
+  BPoint *bp = lt->def;
+  const float(*fp)[3] = kb->data;
+  const int tot = min_ii(kb->totelem, lt->pntsu * lt->pntsv * lt->pntsw);
 
-  for (a = 0; a < tot; a++, fp++, bp++) {
-    copy_v3_v3(bp->vec, *fp);
-  }
+  keyblock_data_convert_to_lattice(fp, bp, tot);
 }
 
 /************************* Curve ************************/
@@ -2097,47 +2146,44 @@ void BKE_keyblock_convert_from_curve(const Curve *cu, KeyBlock *kb, const ListBa
   BKE_keyblock_update_from_curve(cu, kb, nurb);
 }
 
-void BKE_keyblock_convert_to_curve(KeyBlock *kb, Curve *UNUSED(cu), ListBase *nurb)
+static void keyblock_data_convert_to_curve(const float *fp, ListBase *nurb, int totpoint)
 {
-  Nurb *nu;
-  BezTriple *bezt;
-  BPoint *bp;
-  const float *fp;
-  int a, tot;
-
-  tot = BKE_keyblock_curve_element_count(nurb);
-  tot = min_ii(kb->totelem, tot);
-
-  fp = kb->data;
-  for (nu = nurb->first; nu && tot > 0; nu = nu->next) {
-    if (nu->bezt) {
-      for (a = nu->pntsu, bezt = nu->bezt; a && (tot -= KEYELEM_ELEM_LEN_BEZTRIPLE) >= 0;
-           a--, bezt++) {
-        for (int i = 0; i < 3; i++) {
-          copy_v3_v3(bezt->vec[i], &fp[i * 3]);
+  for (Nurb *nu = nurb->first; nu && totpoint > 0; nu = nu->next) {
+    if (nu->bezt != NULL) {
+      BezTriple *bezt = nu->bezt;
+      for (int i = nu->pntsu; i && (totpoint -= KEYELEM_ELEM_LEN_BEZTRIPLE) >= 0;
+           i--, bezt++, fp += KEYELEM_FLOAT_LEN_BEZTRIPLE) {
+        for (int j = 0; j < 3; j++) {
+          copy_v3_v3(bezt->vec[j], &fp[j * 3]);
         }
         bezt->tilt = fp[9];
         bezt->radius = fp[10];
-        fp += KEYELEM_FLOAT_LEN_BEZTRIPLE;
       }
     }
     else {
-      for (a = nu->pntsu * nu->pntsv, bp = nu->bp; a && (tot -= KEYELEM_ELEM_LEN_BPOINT) >= 0;
-           a--, bp++) {
+      BPoint *bp = nu->bp;
+      for (int i = nu->pntsu * nu->pntsv; i && (totpoint -= KEYELEM_ELEM_LEN_BPOINT) >= 0;
+           i--, bp++, fp += KEYELEM_FLOAT_LEN_BPOINT) {
         copy_v3_v3(bp->vec, fp);
         bp->tilt = fp[3];
         bp->radius = fp[4];
-        fp += KEYELEM_FLOAT_LEN_BPOINT;
       }
     }
   }
 }
 
+void BKE_keyblock_convert_to_curve(KeyBlock *kb, Curve *UNUSED(cu), ListBase *nurb)
+{
+  const float *fp = kb->data;
+  const int tot = min_ii(kb->totelem, BKE_keyblock_curve_element_count(nurb));
+
+  keyblock_data_convert_to_curve(fp, nurb, tot);
+}
+
 /************************* Mesh ************************/
 
 void BKE_keyblock_update_from_mesh(const Mesh *me, KeyBlock *kb)
 {
-  MVert *mvert;
   float(*fp)[3];
   int a, tot;
 
@@ -2148,7 +2194,7 @@ void BKE_keyblock_update_from_mesh(const Mesh *me, KeyBlock *kb)
     return;
   }
 
-  mvert = me->mvert;
+  const MVert *mvert = BKE_mesh_verts(me);
   fp = kb->data;
   for (a = 0; a < tot; a++, fp++, mvert++) {
     copy_v3_v3(*fp, mvert->co);
@@ -2171,20 +2217,21 @@ void BKE_keyblock_convert_from_mesh(const Mesh *me, const Key *key, KeyBlock *kb
   BKE_keyblock_update_from_mesh(me, kb);
 }
 
-void BKE_keyblock_convert_to_mesh(const KeyBlock *kb, MVert *mvert, const int totvert)
+static void keyblock_data_convert_to_mesh(const float (*fp)[3], MVert *mvert, const int totvert)
 {
-  const float(*fp)[3];
-  int a, tot;
-
-  fp = kb->data;
-
-  tot = min_ii(kb->totelem, totvert);
-
-  for (a = 0; a < tot; a++, fp++, mvert++) {
+  for (int i = 0; i < totvert; i++, fp++, mvert++) {
     copy_v3_v3(mvert->co, *fp);
   }
 }
 
+void BKE_keyblock_convert_to_mesh(const KeyBlock *kb, MVert *mvert, const int totvert)
+{
+  const float(*fp)[3] = kb->data;
+  const int tot = min_ii(kb->totelem, totvert);
+
+  keyblock_data_convert_to_mesh(fp, mvert, tot);
+}
+
 void BKE_keyblock_mesh_calc_normals(const KeyBlock *kb,
                                     const Mesh *mesh,
                                     float (*r_vertnors)[3],
@@ -2195,8 +2242,11 @@ void BKE_keyblock_mesh_calc_normals(const KeyBlock *kb,
     return;
   }
 
-  MVert *mvert = MEM_dupallocN(mesh->mvert);
-  BKE_keyblock_convert_to_mesh(kb, mvert, mesh->totvert);
+  MVert *verts = MEM_dupallocN(BKE_mesh_verts(mesh));
+  BKE_keyblock_convert_to_mesh(kb, verts, mesh->totvert);
+  const MEdge *edges = BKE_mesh_edges(mesh);
+  const MPoly *polys = BKE_mesh_polys(mesh);
+  const MLoop *loops = BKE_mesh_loops(mesh);
 
   const bool loop_normals_needed = r_loopnors != NULL;
   const bool vert_normals_needed = r_vertnors != NULL || loop_normals_needed;
@@ -2217,35 +2267,30 @@ void BKE_keyblock_mesh_calc_normals(const KeyBlock *kb,
   }
 
   if (poly_normals_needed) {
-    BKE_mesh_calc_normals_poly(mvert,
-                               mesh->totvert,
-                               mesh->mloop,
-                               mesh->totloop,
-                               mesh->mpoly,
-                               mesh->totpoly,
-                               poly_normals);
+    BKE_mesh_calc_normals_poly(
+        verts, mesh->totvert, loops, mesh->totloop, polys, mesh->totpoly, poly_normals);
   }
   if (vert_normals_needed) {
-    BKE_mesh_calc_normals_poly_and_vertex(mvert,
+    BKE_mesh_calc_normals_poly_and_vertex(verts,
                                           mesh->totvert,
-                                          mesh->mloop,
+                                          loops,
                                           mesh->totloop,
-                                          mesh->mpoly,
+                                          polys,
                                           mesh->totpoly,
                                           poly_normals,
                                           vert_normals);
   }
   if (loop_normals_needed) {
     short(*clnors)[2] = CustomData_get_layer(&mesh->ldata, CD_CUSTOMLOOPNORMAL); /* May be NULL. */
-    BKE_mesh_normals_loop_split(mvert,
+    BKE_mesh_normals_loop_split(verts,
                                 vert_normals,
                                 mesh->totvert,
-                                mesh->medge,
+                                edges,
                                 mesh->totedge,
-                                mesh->mloop,
+                                loops,
                                 r_loopnors,
                                 mesh->totloop,
-                                mesh->mpoly,
+                                polys,
                                 poly_normals,
                                 mesh->totpoly,
                                 (mesh->flag & ME_AUTOSMOOTH) != 0,
@@ -2261,7 +2306,7 @@ void BKE_keyblock_mesh_calc_normals(const KeyBlock *kb,
   if (free_poly_normals) {
     MEM_freeN(poly_normals);
   }
-  MEM_freeN(mvert);
+  MEM_freeN(verts);
 }
 
 /************************* raw coords ************************/
diff --git a/source/blender/blenkernel/intern/lattice.c b/source/blender/blenkernel/intern/lattice.c
index b5c025a40b6..e0959182fa4 100644
--- a/source/blender/blenkernel/intern/lattice.c
+++ b/source/blender/blenkernel/intern/lattice.c
@@ -190,7 +190,7 @@ IDTypeInfo IDType_ID_LT = {
     .foreach_id = lattice_foreach_id,
     .foreach_cache = NULL,
     .foreach_path = NULL,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = lattice_blend_write,
     .blend_read_data = lattice_blend_read_data,
@@ -398,21 +398,6 @@ Lattice *BKE_lattice_add(Main *bmain, const char *name)
   return lt;
 }
 
-bool object_deform_mball(Object *ob, ListBase *dispbase)
-{
-  if (ob->parent && ob->parent->type == OB_LATTICE && ob->partype == PARSKEL) {
-    DispList *dl;
-
-    for (dl = dispbase->first; dl; dl = dl->next) {
-      BKE_lattice_deform_coords(ob->parent, ob, (float(*)[3])dl->verts, dl->nr, 0, NULL, 1.0f);
-    }
-
-    return true;
-  }
-
-  return false;
-}
-
 static BPoint *latt_bp(Lattice *lt, int u, int v, int w)
 {
   return <->def[BKE_lattice_index_from_uvw(lt, u, v, w)];
diff --git a/source/blender/blenkernel/intern/lattice_deform.c b/source/blender/blenkernel/intern/lattice_deform.c
index 70f8522aab4..3a1c42b9178 100644
--- a/source/blender/blenkernel/intern/lattice_deform.c
+++ b/source/blender/blenkernel/intern/lattice_deform.c
@@ -30,6 +30,7 @@
 #include "BKE_editmesh.h"
 #include "BKE_key.h"
 #include "BKE_lattice.h"
+#include "BKE_mesh.h"
 #include "BKE_modifier.h"
 #include "BKE_object.h"
 
@@ -348,7 +349,8 @@ static void lattice_deform_coords_impl(const Object *ob_lattice,
    * We want either a Mesh/Lattice with no derived data, or derived data with deformverts.
    */
   if (defgrp_name && defgrp_name[0] && ob_target && ELEM(ob_target->type, OB_MESH, OB_LATTICE)) {
-    defgrp_index = BKE_id_defgroup_name_index((ID *)ob_target->data, defgrp_name);
+    defgrp_index = BKE_id_defgroup_name_index(me_target ? &me_target->id : (ID *)ob_target->data,
+                                              defgrp_name);
 
     if (defgrp_index != -1) {
       /* if there's derived data without deformverts, don't use vgroups */
@@ -362,7 +364,7 @@ static void lattice_deform_coords_impl(const Object *ob_lattice,
         dvert = ((Lattice *)ob_target->data)->dvert;
       }
       else {
-        dvert = ((Mesh *)ob_target->data)->dvert;
+        dvert = BKE_mesh_deform_verts((Mesh *)ob_target->data);
       }
     }
   }
diff --git a/source/blender/blenkernel/intern/layer.c b/source/blender/blenkernel/intern/layer.c
index 534ff7f1fbc..d779fc4f512 100644
--- a/source/blender/blenkernel/intern/layer.c
+++ b/source/blender/blenkernel/intern/layer.c
@@ -39,6 +39,7 @@
 #include "DNA_view3d_types.h"
 #include "DNA_windowmanager_types.h"
 #include "DNA_workspace_types.h"
+#include "DNA_world_types.h"
 
 #include "DEG_depsgraph.h"
 #include "DEG_depsgraph_debug.h"
@@ -55,7 +56,8 @@
 static CLG_LogRef LOG = {"bke.layercollection"};
 
 /* Set of flags which are dependent on a collection settings. */
-static const short g_base_collection_flags = (BASE_VISIBLE_DEPSGRAPH | BASE_VISIBLE_VIEWLAYER |
+static const short g_base_collection_flags = (BASE_ENABLED_AND_MAYBE_VISIBLE_IN_VIEWPORT |
+                                              BASE_ENABLED_AND_VISIBLE_IN_DEFAULT_VIEWPORT |
                                               BASE_SELECTABLE | BASE_ENABLED_VIEWPORT |
                                               BASE_ENABLED_RENDER | BASE_HOLDOUT |
                                               BASE_INDIRECT_ONLY);
@@ -282,9 +284,10 @@ void BKE_view_layer_free_ex(ViewLayer *view_layer, const bool do_id_user)
   MEM_freeN(view_layer);
 }
 
-void BKE_view_layer_selected_objects_tag(ViewLayer *view_layer, const int tag)
+void BKE_view_layer_selected_objects_tag(const Scene *scene, ViewLayer *view_layer, const int tag)
 {
-  LISTBASE_FOREACH (Base *, base, &view_layer->object_bases) {
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  LISTBASE_FOREACH (Base *, base, BKE_view_layer_object_bases_get(view_layer)) {
     if ((base->flag & BASE_SELECTED) != 0) {
       base->object->flag |= tag;
     }
@@ -307,9 +310,10 @@ static bool find_scene_collection_in_scene_collections(ListBase *lb, const Layer
   return false;
 }
 
-Object *BKE_view_layer_camera_find(ViewLayer *view_layer)
+Object *BKE_view_layer_camera_find(const Scene *scene, ViewLayer *view_layer)
 {
-  LISTBASE_FOREACH (Base *, base, &view_layer->object_bases) {
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  LISTBASE_FOREACH (Base *, base, BKE_view_layer_object_bases_get(view_layer)) {
     if (base->object->type == OB_CAMERA) {
       return base->object;
     }
@@ -377,6 +381,8 @@ static void view_layer_bases_hash_create(ViewLayer *view_layer, const bool do_ba
 
 Base *BKE_view_layer_base_find(ViewLayer *view_layer, Object *ob)
 {
+  BLI_assert_msg((view_layer->flag & VIEW_LAYER_OUT_OF_SYNC) == 0,
+                 "View layer out of sync, invoke BKE_view_layer_synced_ensure.");
   if (!view_layer->object_bases_hash) {
     view_layer_bases_hash_create(view_layer, false);
   }
@@ -384,11 +390,10 @@ Base *BKE_view_layer_base_find(ViewLayer *view_layer, Object *ob)
   return BLI_ghash_lookup(view_layer->object_bases_hash, ob);
 }
 
-void BKE_view_layer_base_deselect_all(ViewLayer *view_layer)
+void BKE_view_layer_base_deselect_all(const Scene *scene, ViewLayer *view_layer)
 {
-  Base *base;
-
-  for (base = view_layer->object_bases.first; base; base = base->next) {
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  LISTBASE_FOREACH (Base *, base, BKE_view_layer_object_bases_get(view_layer)) {
     base->flag &= ~BASE_SELECTED;
   }
 }
@@ -500,7 +505,9 @@ void BKE_view_layer_copy_data(Scene *scene_dst,
   /* Copy layer collections and object bases. */
   /* Inline 'BLI_duplicatelist' and update the active base. */
   BLI_listbase_clear(&view_layer_dst->object_bases);
-  LISTBASE_FOREACH (Base *, base_src, &view_layer_src->object_bases) {
+  BLI_assert_msg((view_layer_src->flag & VIEW_LAYER_OUT_OF_SYNC) == 0,
+                 "View Layer Object Base out of sync, invoke BKE_view_layer_synced_ensure.");
+  LISTBASE_FOREACH (const Base *, base_src, &view_layer_src->object_bases) {
     Base *base_dst = MEM_dupallocN(base_src);
     BLI_addtail(&view_layer_dst->object_bases, base_dst);
     if (view_layer_src->basact == base_src) {
@@ -571,7 +578,7 @@ void BKE_view_layer_rename(Main *bmain, Scene *scene, ViewLayer *view_layer, con
   }
 
   /* Dependency graph uses view layer name based lookups. */
-  DEG_id_tag_update(&scene->id, 0);
+  DEG_id_tag_update(&scene->id, ID_RECALC_BASE_FLAGS);
 }
 
 /* LayerCollection */
@@ -955,6 +962,19 @@ static void layer_collection_resync_unused_layers_free(ViewLayer *view_layer,
   }
 }
 
+void BKE_view_layer_need_resync_tag(struct ViewLayer *view_layer)
+{
+  view_layer->flag |= VIEW_LAYER_OUT_OF_SYNC;
+}
+
+void BKE_view_layer_synced_ensure(const Scene *scene, struct ViewLayer *view_layer)
+{
+  if (view_layer->flag & VIEW_LAYER_OUT_OF_SYNC) {
+    BKE_layer_collection_sync(scene, view_layer);
+    view_layer->flag &= ~VIEW_LAYER_OUT_OF_SYNC;
+  }
+}
+
 static void layer_collection_objects_sync(ViewLayer *view_layer,
                                           LayerCollection *layer,
                                           ListBase *r_lb_new_object_bases,
@@ -997,9 +1017,10 @@ static void layer_collection_objects_sync(ViewLayer *view_layer,
     }
 
     if ((collection_restrict & COLLECTION_HIDE_VIEWPORT) == 0) {
-      base->flag_from_collection |= (BASE_ENABLED_VIEWPORT | BASE_VISIBLE_DEPSGRAPH);
+      base->flag_from_collection |= (BASE_ENABLED_VIEWPORT |
+                                     BASE_ENABLED_AND_MAYBE_VISIBLE_IN_VIEWPORT);
       if ((layer_restrict & LAYER_COLLECTION_HIDE) == 0) {
-        base->flag_from_collection |= BASE_VISIBLE_VIEWLAYER;
+        base->flag_from_collection |= BASE_ENABLED_AND_VISIBLE_IN_DEFAULT_VIEWPORT;
       }
       if (((collection_restrict & COLLECTION_HIDE_SELECT) == 0)) {
         base->flag_from_collection |= BASE_SELECTABLE;
@@ -1047,8 +1068,14 @@ static void layer_collection_sync(ViewLayer *view_layer,
 
   BLI_assert(layer_resync->is_used);
 
+  uint64_t skipped_children = 0;
   LISTBASE_FOREACH (CollectionChild *, child, &layer_resync->collection->children) {
     Collection *child_collection = child->collection;
+    /* Collection relations may not have rebuild yet. */
+    if (child_collection == NULL) {
+      skipped_children++;
+      continue;
+    }
     LayerCollectionResync *child_layer_resync = layer_collection_resync_find(layer_resync,
                                                                              child_collection);
 
@@ -1153,7 +1180,7 @@ static void layer_collection_sync(ViewLayer *view_layer,
 
   /* Replace layer collection list with new one. */
   layer_resync->layer->layer_collections = new_lb_layer;
-  BLI_assert(BLI_listbase_count(&layer_resync->collection->children) ==
+  BLI_assert(BLI_listbase_count(&layer_resync->collection->children) - skipped_children ==
              BLI_listbase_count(&new_lb_layer));
 
   /* Update bases etc. for objects. */
@@ -1339,7 +1366,7 @@ void BKE_scene_collection_sync(const Scene *scene)
   }
 
   LISTBASE_FOREACH (ViewLayer *, view_layer, &scene->view_layers) {
-    BKE_layer_collection_sync(scene, view_layer);
+    BKE_view_layer_need_resync_tag(view_layer);
   }
 }
 
@@ -1377,12 +1404,12 @@ void BKE_main_collection_sync_remap(const Main *bmain)
       if (view_layer->object_bases_hash) {
         BLI_ghash_free(view_layer->object_bases_hash, NULL, NULL);
         view_layer->object_bases_hash = NULL;
-
-        /* Directly re-create the mapping here, so that we can also deal with duplicates in
-         * `view_layer->object_bases` list of bases properly. This is the only place where such
-         * duplicates should be fixed, and not considered as a critical error. */
-        view_layer_bases_hash_create(view_layer, true);
       }
+
+      /* Directly re-create the mapping here, so that we can also deal with duplicates in
+       * `view_layer->object_bases` list of bases properly. This is the only place where such
+       * duplicates should be fixed, and not considered as a critical error. */
+      view_layer_bases_hash_create(view_layer, true);
     }
 
     BKE_collection_object_cache_free(scene->master_collection);
@@ -1405,7 +1432,10 @@ void BKE_main_collection_sync_remap(const Main *bmain)
 /** \name Object Selection
  * \{ */
 
-bool BKE_layer_collection_objects_select(ViewLayer *view_layer, LayerCollection *lc, bool deselect)
+bool BKE_layer_collection_objects_select(const Scene *scene,
+                                         ViewLayer *view_layer,
+                                         LayerCollection *lc,
+                                         bool deselect)
 {
   if (lc->collection->flag & COLLECTION_HIDE_SELECT) {
     return false;
@@ -1414,6 +1444,7 @@ bool BKE_layer_collection_objects_select(ViewLayer *view_layer, LayerCollection
   bool changed = false;
 
   if (!(lc->flag & LAYER_COLLECTION_EXCLUDE)) {
+    BKE_view_layer_synced_ensure(scene, view_layer);
     LISTBASE_FOREACH (CollectionObject *, cob, &lc->collection->gobject) {
       Base *base = BKE_view_layer_base_find(view_layer, cob->ob);
 
@@ -1435,30 +1466,34 @@ bool BKE_layer_collection_objects_select(ViewLayer *view_layer, LayerCollection
   }
 
   LISTBASE_FOREACH (LayerCollection *, iter, &lc->layer_collections) {
-    changed |= BKE_layer_collection_objects_select(view_layer, iter, deselect);
+    changed |= BKE_layer_collection_objects_select(scene, view_layer, iter, deselect);
   }
 
   return changed;
 }
 
-bool BKE_layer_collection_has_selected_objects(ViewLayer *view_layer, LayerCollection *lc)
+bool BKE_layer_collection_has_selected_objects(const Scene *scene,
+                                               ViewLayer *view_layer,
+                                               LayerCollection *lc)
 {
   if (lc->collection->flag & COLLECTION_HIDE_SELECT) {
     return false;
   }
 
   if (!(lc->flag & LAYER_COLLECTION_EXCLUDE)) {
+    BKE_view_layer_synced_ensure(scene, view_layer);
     LISTBASE_FOREACH (CollectionObject *, cob, &lc->collection->gobject) {
       Base *base = BKE_view_layer_base_find(view_layer, cob->ob);
 
-      if (base && (base->flag & BASE_SELECTED) && (base->flag & BASE_VISIBLE_DEPSGRAPH)) {
+      if (base && (base->flag & BASE_SELECTED) &&
+          (base->flag & BASE_ENABLED_AND_MAYBE_VISIBLE_IN_VIEWPORT)) {
         return true;
       }
     }
   }
 
   LISTBASE_FOREACH (LayerCollection *, iter, &lc->layer_collections) {
-    if (BKE_layer_collection_has_selected_objects(view_layer, iter)) {
+    if (BKE_layer_collection_has_selected_objects(scene, view_layer, iter)) {
       return true;
     }
   }
@@ -1491,7 +1526,8 @@ void BKE_base_set_visible(Scene *scene, ViewLayer *view_layer, Base *base, bool
 {
   if (!extend) {
     /* Make only one base visible. */
-    LISTBASE_FOREACH (Base *, other, &view_layer->object_bases) {
+    BKE_view_layer_synced_ensure(scene, view_layer);
+    LISTBASE_FOREACH (Base *, other, BKE_view_layer_object_bases_get(view_layer)) {
       other->flag |= BASE_HIDDEN;
     }
 
@@ -1502,17 +1538,17 @@ void BKE_base_set_visible(Scene *scene, ViewLayer *view_layer, Base *base, bool
     base->flag ^= BASE_HIDDEN;
   }
 
-  BKE_layer_collection_sync(scene, view_layer);
+  BKE_view_layer_need_resync_tag(view_layer);
 }
 
 bool BKE_base_is_visible(const View3D *v3d, const Base *base)
 {
-  if ((base->flag & BASE_VISIBLE_DEPSGRAPH) == 0) {
+  if ((base->flag & BASE_ENABLED_AND_MAYBE_VISIBLE_IN_VIEWPORT) == 0) {
     return false;
   }
 
   if (v3d == NULL) {
-    return base->flag & BASE_VISIBLE_VIEWLAYER;
+    return base->flag & BASE_ENABLED_AND_VISIBLE_IN_DEFAULT_VIEWPORT;
   }
 
   if ((v3d->localvd) && ((v3d->local_view_uuid & base->local_view_bits) == 0)) {
@@ -1527,7 +1563,7 @@ bool BKE_base_is_visible(const View3D *v3d, const Base *base)
     return (v3d->local_collections_uuid & base->local_collections_bits) != 0;
   }
 
-  return base->flag & BASE_VISIBLE_VIEWLAYER;
+  return base->flag & BASE_ENABLED_AND_VISIBLE_IN_DEFAULT_VIEWPORT;
 }
 
 bool BKE_object_is_visible_in_viewport(const View3D *v3d, const struct Object *ob)
@@ -1553,7 +1589,7 @@ bool BKE_object_is_visible_in_viewport(const View3D *v3d, const struct Object *o
 
   /* If not using local collection the object may still be in a hidden collection. */
   if ((v3d->flag & V3D_LOCAL_COLLECTIONS) == 0) {
-    return (ob->base_flag & BASE_VISIBLE_VIEWLAYER) != 0;
+    return (ob->base_flag & BASE_ENABLED_AND_VISIBLE_IN_DEFAULT_VIEWPORT) != 0;
   }
 
   return true;
@@ -1581,7 +1617,7 @@ static void layer_collection_flag_unset_recursive(LayerCollection *lc, const int
   }
 }
 
-void BKE_layer_collection_isolate_global(Scene *scene,
+void BKE_layer_collection_isolate_global(Scene *UNUSED(scene),
                                          ViewLayer *view_layer,
                                          LayerCollection *lc,
                                          bool extend)
@@ -1626,7 +1662,7 @@ void BKE_layer_collection_isolate_global(Scene *scene,
     BKE_layer_collection_activate(view_layer, lc);
   }
 
-  BKE_layer_collection_sync(scene, view_layer);
+  BKE_view_layer_need_resync_tag(view_layer);
 }
 
 static void layer_collection_local_visibility_set_recursive(LayerCollection *layer_collection,
@@ -1647,7 +1683,8 @@ static void layer_collection_local_visibility_unset_recursive(LayerCollection *l
   }
 }
 
-static void layer_collection_local_sync(ViewLayer *view_layer,
+static void layer_collection_local_sync(const Scene *scene,
+                                        ViewLayer *view_layer,
                                         LayerCollection *layer_collection,
                                         const unsigned short local_collections_uuid,
                                         bool visible)
@@ -1662,6 +1699,7 @@ static void layer_collection_local_sync(ViewLayer *view_layer,
         continue;
       }
 
+      BKE_view_layer_synced_ensure(scene, view_layer);
       Base *base = BKE_view_layer_base_find(view_layer, cob->ob);
       base->local_collections_bits |= local_collections_uuid;
     }
@@ -1669,12 +1707,12 @@ static void layer_collection_local_sync(ViewLayer *view_layer,
 
   LISTBASE_FOREACH (LayerCollection *, child, &layer_collection->layer_collections) {
     if ((child->flag & LAYER_COLLECTION_EXCLUDE) == 0) {
-      layer_collection_local_sync(view_layer, child, local_collections_uuid, visible);
+      layer_collection_local_sync(scene, view_layer, child, local_collections_uuid, visible);
     }
   }
 }
 
-void BKE_layer_collection_local_sync(ViewLayer *view_layer, const View3D *v3d)
+void BKE_layer_collection_local_sync(const Scene *scene, ViewLayer *view_layer, const View3D *v3d)
 {
   if (no_resync) {
     return;
@@ -1683,12 +1721,13 @@ void BKE_layer_collection_local_sync(ViewLayer *view_layer, const View3D *v3d)
   const unsigned short local_collections_uuid = v3d->local_collections_uuid;
 
   /* Reset flags and set the bases visible by default. */
-  LISTBASE_FOREACH (Base *, base, &view_layer->object_bases) {
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  LISTBASE_FOREACH (Base *, base, BKE_view_layer_object_bases_get(view_layer)) {
     base->local_collections_bits &= ~local_collections_uuid;
   }
 
   LISTBASE_FOREACH (LayerCollection *, layer_collection, &view_layer->layer_collections) {
-    layer_collection_local_sync(view_layer, layer_collection, local_collections_uuid, true);
+    layer_collection_local_sync(scene, view_layer, layer_collection, local_collections_uuid, true);
   }
 }
 
@@ -1707,7 +1746,7 @@ void BKE_layer_collection_local_sync_all(const Main *bmain)
           }
           View3D *v3d = area->spacedata.first;
           if (v3d->flag & V3D_LOCAL_COLLECTIONS) {
-            BKE_layer_collection_local_sync(view_layer, v3d);
+            BKE_layer_collection_local_sync(scene, view_layer, v3d);
           }
         }
       }
@@ -1715,10 +1754,8 @@ void BKE_layer_collection_local_sync_all(const Main *bmain)
   }
 }
 
-void BKE_layer_collection_isolate_local(ViewLayer *view_layer,
-                                        const View3D *v3d,
-                                        LayerCollection *lc,
-                                        bool extend)
+void BKE_layer_collection_isolate_local(
+    const Scene *scene, ViewLayer *view_layer, const View3D *v3d, LayerCollection *lc, bool extend)
 {
   LayerCollection *lc_master = view_layer->layer_collections.first;
   bool hide_it = extend && ((v3d->local_collections_uuid & lc->local_collections_bits) != 0);
@@ -1758,36 +1795,43 @@ void BKE_layer_collection_isolate_local(ViewLayer *view_layer,
     layer_collection_local_visibility_set_recursive(lc, v3d->local_collections_uuid);
   }
 
-  BKE_layer_collection_local_sync(view_layer, v3d);
+  BKE_layer_collection_local_sync(scene, view_layer, v3d);
 }
 
-static void layer_collection_bases_show_recursive(ViewLayer *view_layer, LayerCollection *lc)
+static void layer_collection_bases_show_recursive(const Scene *scene,
+                                                  ViewLayer *view_layer,
+                                                  LayerCollection *lc)
 {
   if ((lc->flag & LAYER_COLLECTION_EXCLUDE) == 0) {
+    BKE_view_layer_synced_ensure(scene, view_layer);
     LISTBASE_FOREACH (CollectionObject *, cob, &lc->collection->gobject) {
       Base *base = BKE_view_layer_base_find(view_layer, cob->ob);
       base->flag &= ~BASE_HIDDEN;
     }
   }
   LISTBASE_FOREACH (LayerCollection *, lc_iter, &lc->layer_collections) {
-    layer_collection_bases_show_recursive(view_layer, lc_iter);
+    layer_collection_bases_show_recursive(scene, view_layer, lc_iter);
   }
 }
 
-static void layer_collection_bases_hide_recursive(ViewLayer *view_layer, LayerCollection *lc)
+static void layer_collection_bases_hide_recursive(const Scene *scene,
+                                                  ViewLayer *view_layer,
+                                                  LayerCollection *lc)
 {
   if ((lc->flag & LAYER_COLLECTION_EXCLUDE) == 0) {
+    BKE_view_layer_synced_ensure(scene, view_layer);
     LISTBASE_FOREACH (CollectionObject *, cob, &lc->collection->gobject) {
       Base *base = BKE_view_layer_base_find(view_layer, cob->ob);
       base->flag |= BASE_HIDDEN;
     }
   }
   LISTBASE_FOREACH (LayerCollection *, lc_iter, &lc->layer_collections) {
-    layer_collection_bases_hide_recursive(view_layer, lc_iter);
+    layer_collection_bases_hide_recursive(scene, view_layer, lc_iter);
   }
 }
 
-void BKE_layer_collection_set_visible(ViewLayer *view_layer,
+void BKE_layer_collection_set_visible(const Scene *scene,
+                                      ViewLayer *view_layer,
                                       LayerCollection *lc,
                                       const bool visible,
                                       const bool hierarchy)
@@ -1795,11 +1839,11 @@ void BKE_layer_collection_set_visible(ViewLayer *view_layer,
   if (hierarchy) {
     if (visible) {
       layer_collection_flag_unset_recursive(lc, LAYER_COLLECTION_HIDE);
-      layer_collection_bases_show_recursive(view_layer, lc);
+      layer_collection_bases_show_recursive(scene, view_layer, lc);
     }
     else {
       layer_collection_flag_set_recursive(lc, LAYER_COLLECTION_HIDE);
-      layer_collection_bases_hide_recursive(view_layer, lc);
+      layer_collection_bases_hide_recursive(scene, view_layer, lc);
     }
   }
   else {
@@ -1894,6 +1938,7 @@ bool BKE_view_layer_has_collection(const ViewLayer *view_layer, const Collection
 bool BKE_scene_has_object(Scene *scene, Object *ob)
 {
   LISTBASE_FOREACH (ViewLayer *, view_layer, &scene->view_layers) {
+    BKE_view_layer_synced_ensure(scene, view_layer);
     Base *base = BKE_view_layer_base_find(view_layer, ob);
     if (base) {
       return true;
@@ -1933,7 +1978,7 @@ static void object_bases_iterator_begin(BLI_Iterator *iter, void *data_in_v, con
   ObjectsVisibleIteratorData *data_in = data_in_v;
   ViewLayer *view_layer = data_in->view_layer;
   const View3D *v3d = data_in->v3d;
-  Base *base = view_layer->object_bases.first;
+  Base *base = BKE_view_layer_object_bases_get(view_layer)->first;
 
   /* when there are no objects */
   if (base == NULL) {
@@ -2010,12 +2055,13 @@ static void objects_iterator_end(BLI_Iterator *iter)
 
 void BKE_view_layer_selected_objects_iterator_begin(BLI_Iterator *iter, void *data_in)
 {
-  objects_iterator_begin(iter, data_in, BASE_VISIBLE_DEPSGRAPH | BASE_SELECTED);
+  objects_iterator_begin(
+      iter, data_in, BASE_ENABLED_AND_MAYBE_VISIBLE_IN_VIEWPORT | BASE_SELECTED);
 }
 
 void BKE_view_layer_selected_objects_iterator_next(BLI_Iterator *iter)
 {
-  objects_iterator_next(iter, BASE_VISIBLE_DEPSGRAPH | BASE_SELECTED);
+  objects_iterator_next(iter, BASE_ENABLED_AND_MAYBE_VISIBLE_IN_VIEWPORT | BASE_SELECTED);
 }
 
 void BKE_view_layer_selected_objects_iterator_end(BLI_Iterator *iter)
@@ -2052,7 +2098,8 @@ void BKE_view_layer_visible_objects_iterator_end(BLI_Iterator *iter)
 
 void BKE_view_layer_selected_editable_objects_iterator_begin(BLI_Iterator *iter, void *data_in)
 {
-  objects_iterator_begin(iter, data_in, BASE_VISIBLE_DEPSGRAPH | BASE_SELECTED);
+  objects_iterator_begin(
+      iter, data_in, BASE_ENABLED_AND_MAYBE_VISIBLE_IN_VIEWPORT | BASE_SELECTED);
   if (iter->valid) {
     if (BKE_object_is_libdata((Object *)iter->current) == false) {
       /* First object is valid (selectable and not libdata) -> all good. */
@@ -2069,7 +2116,7 @@ void BKE_view_layer_selected_editable_objects_iterator_next(BLI_Iterator *iter)
   /* Search while there are objects and the one we have is not editable (editable = not libdata).
    */
   do {
-    objects_iterator_next(iter, BASE_VISIBLE_DEPSGRAPH | BASE_SELECTED);
+    objects_iterator_next(iter, BASE_ENABLED_AND_MAYBE_VISIBLE_IN_VIEWPORT | BASE_SELECTED);
   } while (iter->valid && BKE_object_is_libdata((Object *)iter->current) != false);
 }
 
@@ -2086,12 +2133,13 @@ void BKE_view_layer_selected_editable_objects_iterator_end(BLI_Iterator *iter)
 
 void BKE_view_layer_selected_bases_iterator_begin(BLI_Iterator *iter, void *data_in)
 {
-  objects_iterator_begin(iter, data_in, BASE_VISIBLE_DEPSGRAPH | BASE_SELECTED);
+  objects_iterator_begin(
+      iter, data_in, BASE_ENABLED_AND_MAYBE_VISIBLE_IN_VIEWPORT | BASE_SELECTED);
 }
 
 void BKE_view_layer_selected_bases_iterator_next(BLI_Iterator *iter)
 {
-  object_bases_iterator_next(iter, BASE_VISIBLE_DEPSGRAPH | BASE_SELECTED);
+  object_bases_iterator_next(iter, BASE_ENABLED_AND_MAYBE_VISIBLE_IN_VIEWPORT | BASE_SELECTED);
 }
 
 void BKE_view_layer_selected_bases_iterator_end(BLI_Iterator *iter)
@@ -2218,7 +2266,8 @@ void BKE_base_eval_flags(Base *base)
    * can change these again, but for tools we always want the viewport
    * visibility to be in sync regardless if depsgraph was evaluated. */
   if (!(base->flag & BASE_ENABLED_VIEWPORT) || (base->flag & BASE_HIDDEN)) {
-    base->flag &= ~(BASE_VISIBLE_DEPSGRAPH | BASE_VISIBLE_VIEWLAYER | BASE_SELECTABLE);
+    base->flag &= ~(BASE_ENABLED_AND_MAYBE_VISIBLE_IN_VIEWPORT |
+                    BASE_ENABLED_AND_VISIBLE_IN_DEFAULT_VIEWPORT | BASE_SELECTABLE);
   }
 
   /* Deselect unselectable objects. */
@@ -2228,18 +2277,19 @@ void BKE_base_eval_flags(Base *base)
 }
 
 static void layer_eval_view_layer(struct Depsgraph *depsgraph,
-                                  struct Scene *UNUSED(scene),
+                                  struct Scene *scene,
                                   ViewLayer *view_layer)
 {
   DEG_debug_print_eval(depsgraph, __func__, view_layer->name, view_layer);
 
   /* Create array of bases, for fast index-based lookup. */
-  const int num_object_bases = BLI_listbase_count(&view_layer->object_bases);
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  const int num_object_bases = BLI_listbase_count(BKE_view_layer_object_bases_get(view_layer));
   MEM_SAFE_FREE(view_layer->object_bases_array);
   view_layer->object_bases_array = MEM_malloc_arrayN(
       num_object_bases, sizeof(Base *), "view_layer->object_bases_array");
   int base_index = 0;
-  LISTBASE_FOREACH (Base *, base, &view_layer->object_bases) {
+  LISTBASE_FOREACH (Base *, base, BKE_view_layer_object_bases_get(view_layer)) {
     view_layer->object_bases_array[base_index++] = base;
   }
 }
@@ -2269,10 +2319,11 @@ static void write_layer_collections(BlendWriter *writer, ListBase *lb)
   }
 }
 
-void BKE_view_layer_blend_write(BlendWriter *writer, ViewLayer *view_layer)
+void BKE_view_layer_blend_write(BlendWriter *writer, const Scene *scene, ViewLayer *view_layer)
 {
+  BKE_view_layer_synced_ensure(scene, view_layer);
   BLO_write_struct(writer, ViewLayer, view_layer);
-  BLO_write_struct_list(writer, Base, &view_layer->object_bases);
+  BLO_write_struct_list(writer, Base, BKE_view_layer_object_bases_get(view_layer));
 
   if (view_layer->id_properties) {
     IDP_BlendWrite(writer, view_layer->id_properties);
@@ -2302,7 +2353,7 @@ static void direct_link_layer_collections(BlendDataReader *reader, ListBase *lb,
     BLO_read_data_address(reader, &lc->scene_collection);
 #endif
 
-    /* Master collection is not a real data-lock. */
+    /* Master collection is not a real data-block. */
     if (master) {
       BLO_read_data_address(reader, &lc->collection);
     }
@@ -2342,7 +2393,7 @@ static void lib_link_layer_collection(BlendLibReader *reader,
                                       LayerCollection *layer_collection,
                                       bool master)
 {
-  /* Master collection is not a real data-lock. */
+  /* Master collection is not a real data-block. */
   if (!master) {
     BLO_read_id_address(reader, lib, &layer_collection->collection);
   }
@@ -2383,7 +2434,7 @@ void BKE_view_layer_blend_read_lib(BlendLibReader *reader, Library *lib, ViewLay
 
   BLO_read_id_address(reader, lib, &view_layer->mat_override);
 
-  IDP_BlendReadLib(reader, view_layer->id_properties);
+  IDP_BlendReadLib(reader, lib, view_layer->id_properties);
 }
 
 /** \} */
@@ -2588,12 +2639,36 @@ ViewLayer *BKE_view_layer_find_with_lightgroup(struct Scene *scene,
   return NULL;
 }
 
-void BKE_view_layer_rename_lightgroup(ViewLayer *view_layer,
+void BKE_view_layer_rename_lightgroup(Scene *scene,
+                                      ViewLayer *view_layer,
                                       ViewLayerLightgroup *lightgroup,
                                       const char *name)
 {
+  char old_name[64];
+  BLI_strncpy_utf8(old_name, lightgroup->name, sizeof(old_name));
   BLI_strncpy_utf8(lightgroup->name, name, sizeof(lightgroup->name));
   viewlayer_lightgroup_make_name_unique(view_layer, lightgroup);
+
+  if (scene != NULL) {
+    /* Update objects in the scene to refer to the new name instead. */
+    FOREACH_SCENE_OBJECT_BEGIN (scene, ob) {
+      if (!ID_IS_LINKED(ob) && ob->lightgroup != NULL) {
+        LightgroupMembership *lgm = ob->lightgroup;
+        if (STREQ(lgm->name, old_name)) {
+          BLI_strncpy_utf8(lgm->name, lightgroup->name, sizeof(lgm->name));
+        }
+      }
+    }
+    FOREACH_SCENE_OBJECT_END;
+
+    /* Update the scene's world to refer to the new name instead. */
+    if (scene->world != NULL && !ID_IS_LINKED(scene->world) && scene->world->lightgroup != NULL) {
+      LightgroupMembership *lgm = scene->world->lightgroup;
+      if (STREQ(lgm->name, old_name)) {
+        BLI_strncpy_utf8(lgm->name, lightgroup->name, sizeof(lgm->name));
+      }
+    }
+  }
 }
 
 void BKE_lightgroup_membership_get(struct LightgroupMembership *lgm, char *name)
diff --git a/source/blender/blenkernel/intern/layer_utils.c b/source/blender/blenkernel/intern/layer_utils.c
index 0903c2a2cac..23067d1a4e3 100644
--- a/source/blender/blenkernel/intern/layer_utils.c
+++ b/source/blender/blenkernel/intern/layer_utils.c
@@ -84,13 +84,14 @@ Object **BKE_view_layer_array_selected_objects_params(
 /** \name Objects in Mode Array
  * \{ */
 
-Base **BKE_view_layer_array_from_bases_in_mode_params(ViewLayer *view_layer,
+Base **BKE_view_layer_array_from_bases_in_mode_params(const Scene *scene,
+                                                      ViewLayer *view_layer,
                                                       const View3D *v3d,
                                                       uint *r_len,
                                                       const struct ObjectsInModeParams *params)
 {
   if (params->no_dup_data) {
-    FOREACH_BASE_IN_MODE_BEGIN (view_layer, v3d, -1, params->object_mode, base_iter) {
+    FOREACH_BASE_IN_MODE_BEGIN (scene, view_layer, v3d, -1, params->object_mode, base_iter) {
       ID *id = base_iter->object->data;
       if (id) {
         id->tag |= LIB_TAG_DOIT;
@@ -102,7 +103,7 @@ Base **BKE_view_layer_array_from_bases_in_mode_params(ViewLayer *view_layer,
   Base **base_array = NULL;
   BLI_array_declare(base_array);
 
-  FOREACH_BASE_IN_MODE_BEGIN (view_layer, v3d, -1, params->object_mode, base_iter) {
+  FOREACH_BASE_IN_MODE_BEGIN (scene, view_layer, v3d, -1, params->object_mode, base_iter) {
     if (params->filter_fn) {
       if (!params->filter_fn(base_iter->object, params->filter_userdata)) {
         continue;
@@ -134,13 +135,14 @@ Base **BKE_view_layer_array_from_bases_in_mode_params(ViewLayer *view_layer,
   return base_array;
 }
 
-Object **BKE_view_layer_array_from_objects_in_mode_params(ViewLayer *view_layer,
+Object **BKE_view_layer_array_from_objects_in_mode_params(const Scene *scene,
+                                                          ViewLayer *view_layer,
                                                           const View3D *v3d,
                                                           uint *r_len,
                                                           const struct ObjectsInModeParams *params)
 {
   Base **base_array = BKE_view_layer_array_from_bases_in_mode_params(
-      view_layer, v3d, r_len, params);
+      scene, view_layer, v3d, r_len, params);
   if (base_array != NULL) {
     for (uint i = 0; i < *r_len; i++) {
       ((Object **)base_array)[i] = base_array[i]->object;
@@ -149,6 +151,91 @@ Object **BKE_view_layer_array_from_objects_in_mode_params(ViewLayer *view_layer,
   return (Object **)base_array;
 }
 
+struct Object **BKE_view_layer_array_from_objects_in_edit_mode(const Scene *scene,
+                                                               ViewLayer *view_layer,
+                                                               const View3D *v3d,
+                                                               uint *r_len)
+{
+  struct ObjectsInModeParams params = {0};
+  params.object_mode = OB_MODE_EDIT;
+  return BKE_view_layer_array_from_objects_in_mode_params(scene, view_layer, v3d, r_len, ¶ms);
+}
+
+struct Base **BKE_view_layer_array_from_bases_in_edit_mode(const Scene *scene,
+                                                           ViewLayer *view_layer,
+                                                           const View3D *v3d,
+                                                           uint *r_len)
+{
+  struct ObjectsInModeParams params = {0};
+  params.object_mode = OB_MODE_EDIT;
+  return BKE_view_layer_array_from_bases_in_mode_params(scene, view_layer, v3d, r_len, ¶ms);
+}
+
+struct Object **BKE_view_layer_array_from_objects_in_edit_mode_unique_data(const Scene *scene,
+                                                                           ViewLayer *view_layer,
+                                                                           const View3D *v3d,
+                                                                           uint *r_len)
+{
+  struct ObjectsInModeParams params = {0};
+  params.object_mode = OB_MODE_EDIT;
+  params.no_dup_data = true;
+  return BKE_view_layer_array_from_objects_in_mode_params(scene, view_layer, v3d, r_len, ¶ms);
+}
+
+struct Base **BKE_view_layer_array_from_bases_in_edit_mode_unique_data(const Scene *scene,
+                                                                       ViewLayer *view_layer,
+                                                                       const View3D *v3d,
+                                                                       uint *r_len)
+{
+  struct ObjectsInModeParams params = {0};
+  params.object_mode = OB_MODE_EDIT;
+  params.no_dup_data = true;
+  return BKE_view_layer_array_from_bases_in_mode_params(scene, view_layer, v3d, r_len, ¶ms);
+}
+
+struct Object **BKE_view_layer_array_from_objects_in_edit_mode_unique_data_with_uvs(
+    const Scene *scene, ViewLayer *view_layer, const View3D *v3d, uint *r_len)
+{
+  struct ObjectsInModeParams params = {0};
+  params.object_mode = OB_MODE_EDIT;
+  params.no_dup_data = true;
+  params.filter_fn = BKE_view_layer_filter_edit_mesh_has_uvs;
+  return BKE_view_layer_array_from_objects_in_mode_params(scene, view_layer, v3d, r_len, ¶ms);
+}
+
+struct Object **BKE_view_layer_array_from_objects_in_mode_unique_data(const Scene *scene,
+                                                                      ViewLayer *view_layer,
+                                                                      const View3D *v3d,
+                                                                      uint *r_len,
+                                                                      const eObjectMode mode)
+{
+  struct ObjectsInModeParams params = {0};
+  params.object_mode = mode;
+  params.no_dup_data = true;
+  return BKE_view_layer_array_from_objects_in_mode_params(scene, view_layer, v3d, r_len, ¶ms);
+}
+
+ListBase *BKE_view_layer_object_bases_get(ViewLayer *view_layer)
+{
+  BLI_assert_msg((view_layer->flag & VIEW_LAYER_OUT_OF_SYNC) == 0,
+                 "Object Bases out of sync, invoke BKE_view_layer_synced_ensure.");
+  return &view_layer->object_bases;
+}
+
+Base *BKE_view_layer_active_base_get(ViewLayer *view_layer)
+{
+  BLI_assert_msg((view_layer->flag & VIEW_LAYER_OUT_OF_SYNC) == 0,
+                 "Active Base out of sync, invoke BKE_view_layer_synced_ensure.");
+  return view_layer->basact;
+}
+
+LayerCollection *BKE_view_layer_active_collection_get(ViewLayer *view_layer)
+{
+  BLI_assert_msg((view_layer->flag & VIEW_LAYER_OUT_OF_SYNC) == 0,
+                 "Active Collection out of sync, invoke BKE_view_layer_synced_ensure.");
+  return view_layer->active_collection;
+}
+
 /** \} */
 
 /* -------------------------------------------------------------------- */
@@ -183,10 +270,12 @@ bool BKE_view_layer_filter_edit_mesh_has_edges(const Object *ob, void *UNUSED(us
   return false;
 }
 
-Object *BKE_view_layer_non_active_selected_object(struct ViewLayer *view_layer,
+Object *BKE_view_layer_non_active_selected_object(const struct Scene *scene,
+                                                  struct ViewLayer *view_layer,
                                                   const struct View3D *v3d)
 {
-  Object *ob_active = OBACT(view_layer);
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *ob_active = BKE_view_layer_active_object_get(view_layer);
   Object *ob_result = NULL;
   FOREACH_SELECTED_OBJECT_BEGIN (view_layer, v3d, ob_iter) {
     if (ob_iter == ob_active) {
@@ -206,3 +295,27 @@ Object *BKE_view_layer_non_active_selected_object(struct ViewLayer *view_layer,
 }
 
 /** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Active object accessors.
+ * \{ */
+
+Object *BKE_view_layer_active_object_get(const ViewLayer *view_layer)
+{
+  Base *base = BKE_view_layer_active_base_get((ViewLayer *)view_layer);
+  return base ? base->object : NULL;
+}
+
+Object *BKE_view_layer_edit_object_get(const ViewLayer *view_layer)
+{
+  Object *ob = BKE_view_layer_active_object_get(view_layer);
+  if (ob == NULL) {
+    return NULL;
+  }
+  if (!(ob->mode & OB_MODE_EDIT)) {
+    return NULL;
+  }
+  return ob;
+}
+
+/** \} */
diff --git a/source/blender/blenkernel/intern/lib_id.c b/source/blender/blenkernel/intern/lib_id.c
index 90a4853fd3e..158aaa961ce 100644
--- a/source/blender/blenkernel/intern/lib_id.c
+++ b/source/blender/blenkernel/intern/lib_id.c
@@ -53,11 +53,13 @@
 #include "BKE_lib_query.h"
 #include "BKE_lib_remap.h"
 #include "BKE_main.h"
+#include "BKE_main_namemap.h"
 #include "BKE_node.h"
 #include "BKE_rigidbody.h"
 
 #include "DEG_depsgraph.h"
 #include "DEG_depsgraph_build.h"
+#include "DEG_depsgraph_query.h"
 
 #include "RNA_access.h"
 
@@ -91,7 +93,7 @@ IDTypeInfo IDType_ID_LINK_PLACEHOLDER = {
     .foreach_id = NULL,
     .foreach_cache = NULL,
     .foreach_path = NULL,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = NULL,
     .blend_read_data = NULL,
@@ -178,6 +180,10 @@ void BKE_lib_id_clear_library_data(Main *bmain, ID *id, const int flags)
   const bool id_in_mainlist = (id->tag & LIB_TAG_NO_MAIN) == 0 &&
                               (id->flag & LIB_EMBEDDED_DATA) == 0;
 
+  if (id_in_mainlist) {
+    BKE_main_namemap_remove_name(bmain, id, id->name + 2);
+  }
+
   lib_id_library_local_paths(bmain, id->lib, id);
 
   id_fake_user_clear(id);
@@ -186,7 +192,7 @@ void BKE_lib_id_clear_library_data(Main *bmain, ID *id, const int flags)
   id->tag &= ~(LIB_TAG_INDIRECT | LIB_TAG_EXTERN);
   id->flag &= ~LIB_INDIRECT_WEAK_LINK;
   if (id_in_mainlist) {
-    if (BKE_id_new_name_validate(which_libbase(bmain, GS(id->name)), id, NULL, false)) {
+    if (BKE_id_new_name_validate(bmain, which_libbase(bmain, GS(id->name)), id, NULL, false)) {
       bmain->is_memfile_undo_written = false;
     }
   }
@@ -410,7 +416,7 @@ static int lib_id_expand_local_cb(LibraryIDLinkCallbackData *cb_data)
   /* Can happen that we get un-linkable ID here, e.g. with shape-key referring to itself
    * (through drivers)...
    * Just skip it, shape key can only be either indirectly linked, or fully local, period.
-   * And let's curse one more time that stupid useless shapekey ID type! */
+   * And let's curse one more time that stupid useless shape-key ID type! */
   if (*id_pointer && *id_pointer != id_self &&
       BKE_idtype_idcode_is_linkable(GS((*id_pointer)->name))) {
     id_lib_extern(*id_pointer);
@@ -560,7 +566,7 @@ struct IDCopyLibManagementData {
   int flag;
 };
 
-/* Increases usercount as required, and remap self ID pointers. */
+/** Increases user-count as required, and remap self ID pointers. */
 static int id_copy_libmanagement_cb(LibraryIDLinkCallbackData *cb_data)
 {
   ID **id_pointer = cb_data->id_pointer;
@@ -703,6 +709,58 @@ ID *BKE_id_copy_for_duplicate(Main *bmain,
   return id->newid;
 }
 
+static int foreach_assign_id_to_orig_callback(LibraryIDLinkCallbackData *cb_data)
+{
+  ID **id_p = cb_data->id_pointer;
+
+  if (*id_p) {
+    ID *id = *id_p;
+    *id_p = DEG_get_original_id(id);
+
+    /* If the ID changes increase the user count.
+     *
+     * This means that the reference to evaluated ID has been changed with a reference to the
+     * original ID which implies that the user count of the original ID is increased.
+     *
+     * The evaluated IDs do not maintain their user counter, so do not change it to avoid issues
+     * with the user counter going negative. */
+    if (*id_p != id) {
+      if ((cb_data->cb_flag & IDWALK_CB_USER) != 0) {
+        id_us_plus(*id_p);
+      }
+    }
+  }
+
+  return IDWALK_RET_NOP;
+}
+
+ID *BKE_id_copy_for_use_in_bmain(Main *bmain, const ID *id)
+{
+  ID *newid = BKE_id_copy(bmain, id);
+
+  if (newid == NULL) {
+    return newid;
+  }
+
+  /* Assign ID references directly used by the given ID to their original complementary parts.
+   *
+   * For example, when is called on an evaluated object will assign object->data to its original
+   * pointer, the evaluated object->data will be kept unchanged. */
+  BKE_library_foreach_ID_link(NULL, newid, foreach_assign_id_to_orig_callback, NULL, IDWALK_NOP);
+
+  /* Shape keys reference on evaluated ID is preserved to keep driver paths available, but the key
+   * data is likely to be invalid now due to modifiers, so clear the shape key reference avoiding
+   * any possible shape corruption. */
+  if (DEG_is_evaluated_id(id)) {
+    Key **key_p = BKE_key_from_id_p(newid);
+    if (key_p) {
+      *key_p = NULL;
+    }
+  }
+
+  return newid;
+}
+
 /**
  * Does a mere memory swap over the whole IDs data (including type-specific memory).
  * \note Most internal ID data itself is not swapped (only IDProperties are).
@@ -842,7 +900,7 @@ void BKE_libblock_management_main_add(Main *bmain, void *idv)
   BLI_addtail(lb, id);
   /* We need to allow adding extra datablocks into libraries too, e.g. to support generating new
    * overrides for recursive resync. */
-  BKE_id_new_name_validate(lb, id, NULL, true);
+  BKE_id_new_name_validate(bmain, lb, id, NULL, true);
   /* alphabetic insertion: is in new_id */
   id->tag &= ~(LIB_TAG_NO_MAIN | LIB_TAG_NO_USER_REFCOUNT);
   bmain->is_memfile_undo_written = false;
@@ -865,6 +923,7 @@ void BKE_libblock_management_main_remove(Main *bmain, void *idv)
   ListBase *lb = which_libbase(bmain, GS(id->name));
   BKE_main_lock(bmain);
   BLI_remlink(lb, id);
+  BKE_main_namemap_remove_name(bmain, id, id->name + 2);
   id->tag |= LIB_TAG_NO_MAIN;
   bmain->is_memfile_undo_written = false;
   BKE_main_unlock(bmain);
@@ -958,7 +1017,7 @@ void BKE_main_id_flag_all(Main *bmain, const int flag, const bool value)
   }
 }
 
-void BKE_main_id_repair_duplicate_names_listbase(ListBase *lb)
+void BKE_main_id_repair_duplicate_names_listbase(Main *bmain, ListBase *lb)
 {
   int lb_len = 0;
   LISTBASE_FOREACH (ID *, id, lb) {
@@ -982,7 +1041,7 @@ void BKE_main_id_repair_duplicate_names_listbase(ListBase *lb)
   }
   for (i = 0; i < lb_len; i++) {
     if (!BLI_gset_add(gset, id_array[i]->name + 2)) {
-      BKE_id_new_name_validate(lb, id_array[i], NULL, false);
+      BKE_id_new_name_validate(bmain, lb, id_array[i], NULL, false);
     }
   }
   BLI_gset_free(gset, NULL);
@@ -1073,11 +1132,14 @@ void *BKE_libblock_alloc(Main *bmain, short type, const char *name, const int fl
 
       BKE_main_lock(bmain);
       BLI_addtail(lb, id);
-      BKE_id_new_name_validate(lb, id, name, false);
+      BKE_id_new_name_validate(bmain, lb, id, name, false);
       bmain->is_memfile_undo_written = false;
       /* alphabetic insertion: is in new_id */
       BKE_main_unlock(bmain);
 
+      /* This assert avoids having to keep name_map consistency when changing the library of an ID,
+       * if this check is not true anymore it will have to be done here too. */
+      BLI_assert(bmain->curlib == NULL || bmain->curlib->runtime.name_map == NULL);
       /* This is important in 'readfile doversion after liblink' context mainly, but is a good
        * consistency change in general: ID created for a Main should get that main's current
        * library pointer. */
@@ -1227,7 +1289,7 @@ void BKE_libblock_copy_ex(Main *bmain, const ID *id, ID **r_newid, const int ori
 
   new_id->flag = (new_id->flag & ~copy_idflag_mask) | (id->flag & copy_idflag_mask);
 
-  /* We do not want any handling of usercount in code duplicating the data here, we do that all
+  /* We do not want any handling of user-count in code duplicating the data here, we do that all
    * at once in id_copy_libmanagement_cb() at the end. */
   const int copy_data_flag = orig_flag | LIB_ID_CREATE_NO_USER_REFCOUNT;
 
@@ -1415,255 +1477,8 @@ void id_sort_by_name(ListBase *lb, ID *id, ID *id_sorting_hint)
 #undef ID_SORT_STEP_SIZE
 }
 
-/* NOTE: this code assumes and ensures that the suffix number can never go beyond 1 billion. */
-#define MAX_NUMBER 1000000000
-/* We do not want to get "name.000", so minimal number is 1. */
-#define MIN_NUMBER 1
-/* The maximum value up to which we search for the actual smallest unused number. Beyond that
- * value, we will only use the first biggest unused number, without trying to 'fill the gaps'
- * in-between already used numbers... */
-#define MAX_NUMBERS_IN_USE 1024
-
-/**
- * Helper building final ID name from given base_name and number.
- *
- * If everything goes well and we do generate a valid final ID name in given name, we return
- * true. In case the final name would overflow the allowed ID name length, or given number is
- * bigger than maximum allowed value, we truncate further the base_name (and given name, which is
- * assumed to have the same 'base_name' part), and return false.
- */
-static bool id_name_final_build(char *name, char *base_name, size_t base_name_len, int number)
-{
-  char number_str[11]; /* Dot + nine digits + NULL terminator. */
-  size_t number_str_len = BLI_snprintf_rlen(number_str, ARRAY_SIZE(number_str), ".%.3d", number);
-
-  /* If the number would lead to an overflow of the maximum ID name length, we need to truncate
-   * the base name part and do all the number checks again. */
-  if (base_name_len + number_str_len >= MAX_ID_NAME - 2 || number >= MAX_NUMBER) {
-    if (base_name_len + number_str_len >= MAX_ID_NAME - 2) {
-      base_name_len = MAX_ID_NAME - 2 - number_str_len - 1;
-    }
-    else {
-      base_name_len--;
-    }
-    base_name[base_name_len] = '\0';
-
-    /* Code above may have generated invalid utf-8 string, due to raw truncation.
-     * Ensure we get a valid one now. */
-    base_name_len -= (size_t)BLI_str_utf8_invalid_strip(base_name, base_name_len);
-
-    /* Also truncate orig name, and start the whole check again. */
-    name[base_name_len] = '\0';
-    return false;
-  }
-
-  /* We have our final number, we can put it in name and exit the function. */
-  BLI_strncpy(name + base_name_len, number_str, number_str_len + 1);
-  return true;
-}
-
-/**
- * Check to see if an ID name is already used, and find a new one if so.
- * Return true if a new name was created (returned in name).
- *
- * Normally the ID that's being checked is already in the ListBase, so ID *id points at the new
- * entry. The Python Library module needs to know what the name of a data-block will be before it
- * is appended, in this case ID *id is NULL.
- */
-static bool check_for_dupid(ListBase *lb, ID *id, char *name, ID **r_id_sorting_hint)
-{
-  BLI_assert(strlen(name) < MAX_ID_NAME - 2);
-
-  *r_id_sorting_hint = NULL;
-
-  ID *id_test = lb->first;
-  bool is_name_changed = false;
-
-  if (id_test == NULL) {
-    return is_name_changed;
-  }
-
-  const short id_type = (short)GS(id_test->name);
-
-  /* Static storage of previous handled ID/name info, used to perform a quicker test and optimize
-   * creation of huge number of IDs using the same given base name. */
-  static char prev_orig_base_name[MAX_ID_NAME - 2] = {0};
-  static char prev_final_base_name[MAX_ID_NAME - 2] = {0};
-  static short prev_id_type = ID_LINK_PLACEHOLDER; /* Should never exist in actual ID list. */
-  static int prev_number = MIN_NUMBER - 1;
-
-  /* Initial test to check whether we can 'shortcut' the more complex loop of the main code
-   * below. Note that we do not do that for low numbers, as that would prevent using actual
-   * smallest available number in some cases, and benefits of this special case handling mostly
-   * show up with high numbers anyway. */
-  if (id_type == prev_id_type && prev_number >= MAX_NUMBERS_IN_USE &&
-      prev_number < MAX_NUMBER - 1 && name[0] == prev_final_base_name[0]) {
-
-    /* Get the name and number parts ("name.number"). */
-    char base_name[MAX_ID_NAME - 2];
-    int number = MIN_NUMBER;
-    size_t base_name_len = BLI_split_name_num(base_name, &number, name, '.');
-    size_t prev_final_base_name_len = strlen(prev_final_base_name);
-    size_t prev_orig_base_name_len = strlen(prev_orig_base_name);
-
-    if (base_name_len == prev_orig_base_name_len &&
-        STREQLEN(base_name, prev_orig_base_name, prev_orig_base_name_len)) {
-      /* Once we have ensured given base_name and original previous one are the same, we can
-       * check that previously used number is actually used, and that next one is free. */
-      /* Note that from now on, we only used previous final base name, as it might have been
-       * truncated from original one due to number suffix length. */
-      char final_name[MAX_ID_NAME - 2];
-      char prev_final_name[MAX_ID_NAME - 2];
-      BLI_strncpy(final_name, prev_final_base_name, prev_final_base_name_len + 1);
-      BLI_strncpy(prev_final_name, prev_final_base_name, prev_final_base_name_len + 1);
-
-      if (id_name_final_build(final_name, base_name, prev_final_base_name_len, prev_number + 1) &&
-          id_name_final_build(prev_final_name, base_name, prev_final_base_name_len, prev_number)) {
-        /* We successfully built valid final names of previous and current iterations,
-         * now we have to ensure that previous final name is indeed used in current ID list,
-         * and that current one is not. */
-        bool is_valid = false;
-        for (id_test = lb->first; id_test; id_test = id_test->next) {
-          if (id != id_test && id_test->lib == id->lib) {
-            if (id_test->name[2] == final_name[0] && STREQ(final_name, id_test->name + 2)) {
-              /* We expect final_name to not be already used, so this is a failure. */
-              is_valid = false;
-              break;
-            }
-            /* Previous final name should only be found once in the list, so if it was found
-             * already, no need to do a string comparison again. */
-            if (!is_valid && id_test->name[2] == prev_final_name[0] &&
-                STREQ(prev_final_name, id_test->name + 2)) {
-              is_valid = true;
-              *r_id_sorting_hint = id_test;
-            }
-          }
-        }
-
-        if (is_valid) {
-          /* Only the number changed, prev_orig_base_name, prev_final_base_name and prev_id_type
-           * remain the same. */
-          prev_number++;
-
-          strcpy(name, final_name);
-          return true;
-        }
-      }
-    }
-  }
-
-  /* To speed up finding smallest unused number within [0 .. MAX_NUMBERS_IN_USE - 1].
-   * We do not bother beyond that point. */
-  ID *ids_in_use[MAX_NUMBERS_IN_USE] = {NULL};
-
-  bool is_first_run = true;
-  while (true) {
-    /* Get the name and number parts ("name.number"). */
-    char base_name[MAX_ID_NAME - 2];
-    int number = MIN_NUMBER;
-    size_t base_name_len = BLI_split_name_num(base_name, &number, name, '.');
-
-    /* Store previous original given base name now, as we might alter it later in code below. */
-    if (is_first_run) {
-      strcpy(prev_orig_base_name, base_name);
-      is_first_run = false;
-    }
-
-    /* In case we get an insane initial number suffix in given name. */
-    /* NOTE: BLI_split_name_num() cannot return negative numbers, so we do not have to check for
-     * that here. */
-    if (number >= MAX_NUMBER || number < MIN_NUMBER) {
-      number = MIN_NUMBER;
-    }
-
-    bool is_orig_name_used = false;
-    for (id_test = lb->first; id_test; id_test = id_test->next) {
-      char base_name_test[MAX_ID_NAME - 2];
-      int number_test;
-      if ((id != id_test) && (id_test->lib == id->lib) && (name[0] == id_test->name[2]) &&
-          (ELEM(id_test->name[base_name_len + 2], '.', '\0')) &&
-          STREQLEN(name, id_test->name + 2, base_name_len) &&
-          (BLI_split_name_num(base_name_test, &number_test, id_test->name + 2, '.') ==
-           base_name_len)) {
-        /* If we did not yet encounter exact same name as the given one, check the remaining
-         * parts of the strings. */
-        if (!is_orig_name_used) {
-          is_orig_name_used = STREQ(name + base_name_len, id_test->name + 2 + base_name_len);
-        }
-        /* Mark number of current id_test name as used, if possible. */
-        if (number_test < MAX_NUMBERS_IN_USE) {
-          ids_in_use[number_test] = id_test;
-        }
-        /* Keep track of first largest unused number. */
-        if (number <= number_test) {
-          *r_id_sorting_hint = id_test;
-          number = number_test + 1;
-        }
-      }
-    }
-
-    /* If there is no double, we are done.
-     * Note however that name might have been changed (truncated) in a previous iteration
-     * already.
-     */
-    if (!is_orig_name_used) {
-      /* Don't bother updating `prev_*` static variables here, this case is not supposed to happen
-       * that often, and is not straight-forward here, so just ignore and reset them to default. */
-      prev_id_type = ID_LINK_PLACEHOLDER;
-      prev_final_base_name[0] = '\0';
-      prev_number = MIN_NUMBER - 1;
-
-      /* Value set previously is meaningless in that case. */
-      *r_id_sorting_hint = NULL;
-
-      return is_name_changed;
-    }
-
-    /* Decide which value of number to use, either the smallest unused one if possible, or
-     * default to the first largest unused one we got from previous loop. */
-    for (int i = MIN_NUMBER; i < MAX_NUMBERS_IN_USE; i++) {
-      if (ids_in_use[i] == NULL) {
-        number = i;
-        if (i > 0) {
-          *r_id_sorting_hint = ids_in_use[i - 1];
-        }
-        break;
-      }
-    }
-    /* At this point, number is either the lowest unused number within
-     * [MIN_NUMBER .. MAX_NUMBERS_IN_USE - 1], or 1 greater than the largest used number if all
-     * those low ones are taken.
-     * We can't be bothered to look for the lowest unused number beyond
-     * (MAX_NUMBERS_IN_USE - 1).
-     */
-    /* We know for wure that name will be changed. */
-    is_name_changed = true;
-
-    /* If id_name_final_build helper returns false, it had to truncate further given name, hence
-     * we have to go over the whole check again. */
-    if (!id_name_final_build(name, base_name, base_name_len, number)) {
-      /* We have to clear our list of small used numbers before we do the whole check again. */
-      memset(ids_in_use, 0, sizeof(ids_in_use));
-
-      continue;
-    }
-
-    /* Update `prev_*` static variables, in case next call is for the same type of IDs and with the
-     * same initial base name, we can skip a lot of above process. */
-    prev_id_type = id_type;
-    strcpy(prev_final_base_name, base_name);
-    prev_number = number;
-
-    return is_name_changed;
-  }
-
-#undef MAX_NUMBERS_IN_USE
-}
-
-#undef MIN_NUMBER
-#undef MAX_NUMBER
-
-bool BKE_id_new_name_validate(ListBase *lb, ID *id, const char *tname, const bool do_linked_data)
+bool BKE_id_new_name_validate(
+    struct Main *bmain, ListBase *lb, ID *id, const char *tname, const bool do_linked_data)
 {
   bool result = false;
   char name[MAX_ID_NAME - 2];
@@ -1693,22 +1508,10 @@ bool BKE_id_new_name_validate(ListBase *lb, ID *id, const char *tname, const boo
     BLI_str_utf8_invalid_strip(name, strlen(name));
   }
 
-  ID *id_sorting_hint = NULL;
-  result = check_for_dupid(lb, id, name, &id_sorting_hint);
-  strcpy(id->name + 2, name);
-
-  /* This was in 2.43 and previous releases
-   * however all data in blender should be sorted, not just duplicate names
-   * sorting should not hurt, but noting just in case it alters the way other
-   * functions work, so sort every time. */
-#if 0
-  if (result) {
-    id_sort_by_name(lb, id, id_sorting_hint);
-  }
-#endif
-
-  id_sort_by_name(lb, id, id_sorting_hint);
+  result = BKE_main_namemap_get_name(bmain, id, name);
 
+  strcpy(id->name + 2, name);
+  id_sort_by_name(lb, id, NULL);
   return result;
 }
 
@@ -1763,7 +1566,7 @@ void BKE_main_id_refcount_recompute(struct Main *bmain, const bool do_linked_onl
   }
   FOREACH_MAIN_ID_END;
 
-  /* Go over whole Main database to re-generate proper usercounts... */
+  /* Go over whole Main database to re-generate proper user-counts. */
   FOREACH_MAIN_ID_BEGIN (bmain, id) {
     BKE_library_foreach_ID_link(bmain,
                                 id,
@@ -2074,7 +1877,7 @@ void BLI_libblock_ensure_unique_name(Main *bmain, const char *name)
   idtest = BLI_findstring(lb, name + 2, offsetof(ID, name) + 2);
   if (idtest != NULL && !ID_IS_LINKED(idtest)) {
     /* BKE_id_new_name_validate also takes care of sorting. */
-    BKE_id_new_name_validate(lb, idtest, NULL, false);
+    BKE_id_new_name_validate(bmain, lb, idtest, NULL, false);
     bmain->is_memfile_undo_written = false;
   }
 }
@@ -2082,8 +1885,9 @@ void BLI_libblock_ensure_unique_name(Main *bmain, const char *name)
 void BKE_libblock_rename(Main *bmain, ID *id, const char *name)
 {
   BLI_assert(!ID_IS_LINKED(id));
+  BKE_main_namemap_remove_name(bmain, id, id->name + 2);
   ListBase *lb = which_libbase(bmain, GS(id->name));
-  if (BKE_id_new_name_validate(lb, id, name, false)) {
+  if (BKE_id_new_name_validate(bmain, lb, id, name, false)) {
     bmain->is_memfile_undo_written = false;
   }
 }
@@ -2161,6 +1965,18 @@ bool BKE_id_can_be_asset(const ID *id)
          BKE_idtype_idcode_is_linkable(GS(id->name));
 }
 
+ID *BKE_id_owner_get(ID *id)
+{
+  const IDTypeInfo *idtype = BKE_idtype_get_info_from_id(id);
+  if (idtype->owner_pointer_get != NULL) {
+    ID **owner_id_pointer = idtype->owner_pointer_get(id);
+    if (owner_id_pointer != NULL) {
+      return *owner_id_pointer;
+    }
+  }
+  return NULL;
+}
+
 bool BKE_id_is_editable(const Main *bmain, const ID *id)
 {
   return !(ID_IS_LINKED(id) || BKE_lib_override_library_is_system_defined(bmain, id));
diff --git a/source/blender/blenkernel/intern/lib_id_delete.c b/source/blender/blenkernel/intern/lib_id_delete.c
index f14c11a949e..f4f5ca7a1d7 100644
--- a/source/blender/blenkernel/intern/lib_id_delete.c
+++ b/source/blender/blenkernel/intern/lib_id_delete.c
@@ -28,6 +28,7 @@
 #include "BKE_lib_remap.h"
 #include "BKE_library.h"
 #include "BKE_main.h"
+#include "BKE_main_namemap.h"
 
 #include "lib_intern.h"
 
@@ -151,6 +152,9 @@ void BKE_id_free_ex(Main *bmain, void *idv, int flag, const bool use_flag_from_i
   if ((flag & LIB_ID_FREE_NO_MAIN) == 0) {
     ListBase *lb = which_libbase(bmain, type);
     BLI_remlink(lb, id);
+    if ((flag & LIB_ID_FREE_NO_NAMEMAP_REMOVE) == 0) {
+      BKE_main_namemap_remove_name(bmain, id, id->name + 2);
+    }
   }
 
   BKE_libblock_free_data(id, (flag & LIB_ID_FREE_NO_USER_REFCOUNT) == 0);
@@ -237,6 +241,7 @@ static size_t id_delete(Main *bmain, const bool do_tagged_deletion)
           /* NOTE: in case we delete a library, we also delete all its datablocks! */
           if ((id->tag & tag) || (ID_IS_LINKED(id) && (id->lib->id.tag & tag))) {
             BLI_remlink(lb, id);
+            BKE_main_namemap_remove_name(bmain, id, id->name + 2);
             BLI_addtail(&tagged_deleted_ids, id);
             /* Do not tag as no_main now, we want to unlink it first (lower-level ID management
              * code has some specific handling of 'no main' IDs that would be a problem in that
@@ -275,8 +280,8 @@ static size_t id_delete(Main *bmain, const bool do_tagged_deletion)
     }
 
     /* Now we can safely mark that ID as not being in Main database anymore. */
-    /* NOTE: This needs to be done in a separate loop than above, otherwise some usercounts of
-     * deleted IDs may not be properly decreased by the remappings (since `NO_MAIN` ID usercounts
+    /* NOTE: This needs to be done in a separate loop than above, otherwise some user-counts of
+     * deleted IDs may not be properly decreased by the remappings (since `NO_MAIN` ID user-counts
      * is never affected). */
     for (ID *id = tagged_deleted_ids.first; id; id = id->next) {
       id->tag |= LIB_TAG_NO_MAIN;
diff --git a/source/blender/blenkernel/intern/lib_id_remapper.cc b/source/blender/blenkernel/intern/lib_id_remapper.cc
index 7e75e0f5d93..98ac9110a48 100644
--- a/source/blender/blenkernel/intern/lib_id_remapper.cc
+++ b/source/blender/blenkernel/intern/lib_id_remapper.cc
@@ -36,6 +36,7 @@ struct IDRemapper {
     BLI_assert(old_id != nullptr);
     BLI_assert(new_id == nullptr || (GS(old_id->name) == GS(new_id->name)));
     mappings.add(old_id, new_id);
+    BLI_assert(BKE_idtype_idcode_to_idfilter(GS(old_id->name)) != 0);
     source_types |= BKE_idtype_idcode_to_idfilter(GS(old_id->name));
   }
 
diff --git a/source/blender/blenkernel/intern/lib_id_remapper_test.cc b/source/blender/blenkernel/intern/lib_id_remapper_test.cc
index 73edc30d077..03f456d2d1e 100644
--- a/source/blender/blenkernel/intern/lib_id_remapper_test.cc
+++ b/source/blender/blenkernel/intern/lib_id_remapper_test.cc
@@ -55,6 +55,7 @@ TEST(lib_id_remapper, unassigned)
 {
   ID id1;
   ID *idp = &id1;
+  BLI_strncpy(id1.name, "OB2", sizeof(id1.name));
 
   IDRemapper *remapper = BKE_id_remapper_create();
   BKE_id_remapper_add(remapper, &id1, nullptr);
diff --git a/source/blender/blenkernel/intern/lib_id_test.cc b/source/blender/blenkernel/intern/lib_id_test.cc
index d6101d71be5..d12e0c52870 100644
--- a/source/blender/blenkernel/intern/lib_id_test.cc
+++ b/source/blender/blenkernel/intern/lib_id_test.cc
@@ -10,6 +10,7 @@
 #include "BKE_idtype.h"
 #include "BKE_lib_id.h"
 #include "BKE_main.h"
+#include "BKE_main_namemap.h"
 
 #include "DNA_ID.h"
 #include "DNA_mesh_types.h"
@@ -18,19 +19,18 @@
 namespace blender::bke::tests {
 
 struct LibIDMainSortTestContext {
-  Main *bmain;
-};
-
-static void test_lib_id_main_sort_init(LibIDMainSortTestContext *ctx)
-{
-  BKE_idtype_init();
-  ctx->bmain = BKE_main_new();
-}
+  Main *bmain = nullptr;
 
-static void test_lib_id_main_sort_free(LibIDMainSortTestContext *ctx)
-{
-  BKE_main_free(ctx->bmain);
-}
+  LibIDMainSortTestContext()
+  {
+    BKE_idtype_init();
+    bmain = BKE_main_new();
+  }
+  ~LibIDMainSortTestContext()
+  {
+    BKE_main_free(bmain);
+  }
+};
 
 static void test_lib_id_main_sort_check_order(std::initializer_list list)
 {
@@ -47,8 +47,7 @@ static void test_lib_id_main_sort_check_order(std::initializer_list list)
 
 TEST(lib_id_main_sort, local_ids_1)
 {
-  LibIDMainSortTestContext ctx = {nullptr};
-  test_lib_id_main_sort_init(&ctx);
+  LibIDMainSortTestContext ctx;
   EXPECT_TRUE(BLI_listbase_is_empty(&ctx.bmain->libraries));
 
   ID *id_c = static_cast(BKE_id_new(ctx.bmain, ID_OB, "OB_C"));
@@ -57,14 +56,28 @@ TEST(lib_id_main_sort, local_ids_1)
   EXPECT_TRUE(ctx.bmain->objects.first == id_a);
   EXPECT_TRUE(ctx.bmain->objects.last == id_c);
   test_lib_id_main_sort_check_order({id_a, id_b, id_c});
+}
+
+static void change_lib(Main *bmain, ID *id, Library *lib)
+{
+  if (id->lib == lib) {
+    return;
+  }
+  BKE_main_namemap_remove_name(bmain, id, id->name + 2);
+  id->lib = lib;
+  BKE_main_namemap_get_name(bmain, id, id->name + 2);
+}
 
-  test_lib_id_main_sort_free(&ctx);
+static void change_name(Main *bmain, ID *id, const char *name)
+{
+  BKE_main_namemap_remove_name(bmain, id, id->name + 2);
+  BLI_strncpy(id->name + 2, name, MAX_NAME);
+  BKE_id_new_name_validate(bmain, &bmain->objects, id, nullptr, true);
 }
 
 TEST(lib_id_main_sort, linked_ids_1)
 {
-  LibIDMainSortTestContext ctx = {nullptr};
-  test_lib_id_main_sort_init(&ctx);
+  LibIDMainSortTestContext ctx;
   EXPECT_TRUE(BLI_listbase_is_empty(&ctx.bmain->libraries));
 
   Library *lib_a = static_cast(BKE_id_new(ctx.bmain, ID_LI, "LI_A"));
@@ -73,33 +86,32 @@ TEST(lib_id_main_sort, linked_ids_1)
   ID *id_a = static_cast(BKE_id_new(ctx.bmain, ID_OB, "OB_A"));
   ID *id_b = static_cast(BKE_id_new(ctx.bmain, ID_OB, "OB_B"));
 
-  id_a->lib = lib_a;
+  change_lib(ctx.bmain, id_a, lib_a);
   id_sort_by_name(&ctx.bmain->objects, id_a, nullptr);
-  id_b->lib = lib_a;
+  change_lib(ctx.bmain, id_b, lib_a);
   id_sort_by_name(&ctx.bmain->objects, id_b, nullptr);
   EXPECT_TRUE(ctx.bmain->objects.first == id_c);
   EXPECT_TRUE(ctx.bmain->objects.last == id_b);
   test_lib_id_main_sort_check_order({id_c, id_a, id_b});
 
-  id_a->lib = lib_b;
+  change_lib(ctx.bmain, id_a, lib_b);
   id_sort_by_name(&ctx.bmain->objects, id_a, nullptr);
   EXPECT_TRUE(ctx.bmain->objects.first == id_c);
   EXPECT_TRUE(ctx.bmain->objects.last == id_a);
   test_lib_id_main_sort_check_order({id_c, id_b, id_a});
 
-  id_b->lib = lib_b;
+  change_lib(ctx.bmain, id_b, lib_b);
   id_sort_by_name(&ctx.bmain->objects, id_b, nullptr);
   EXPECT_TRUE(ctx.bmain->objects.first == id_c);
   EXPECT_TRUE(ctx.bmain->objects.last == id_b);
   test_lib_id_main_sort_check_order({id_c, id_a, id_b});
 
-  test_lib_id_main_sort_free(&ctx);
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
 }
 
 TEST(lib_id_main_unique_name, local_ids_1)
 {
-  LibIDMainSortTestContext ctx = {nullptr};
-  test_lib_id_main_sort_init(&ctx);
+  LibIDMainSortTestContext ctx;
   EXPECT_TRUE(BLI_listbase_is_empty(&ctx.bmain->libraries));
 
   ID *id_c = static_cast(BKE_id_new(ctx.bmain, ID_OB, "OB_C"));
@@ -107,21 +119,22 @@ TEST(lib_id_main_unique_name, local_ids_1)
   ID *id_b = static_cast(BKE_id_new(ctx.bmain, ID_OB, "OB_B"));
   test_lib_id_main_sort_check_order({id_a, id_b, id_c});
 
-  BLI_strncpy(id_c->name, id_a->name, sizeof(id_c->name));
-  BKE_id_new_name_validate(&ctx.bmain->objects, id_c, nullptr, false);
-  EXPECT_TRUE(strcmp(id_c->name + 2, "OB_A.001") == 0);
-  EXPECT_TRUE(strcmp(id_a->name + 2, "OB_A") == 0);
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+
+  change_name(ctx.bmain, id_c, "OB_A");
+
+  EXPECT_STREQ(id_c->name + 2, "OB_A.001");
+  EXPECT_STREQ(id_a->name + 2, "OB_A");
   EXPECT_TRUE(ctx.bmain->objects.first == id_a);
   EXPECT_TRUE(ctx.bmain->objects.last == id_b);
   test_lib_id_main_sort_check_order({id_a, id_c, id_b});
 
-  test_lib_id_main_sort_free(&ctx);
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
 }
 
 TEST(lib_id_main_unique_name, linked_ids_1)
 {
-  LibIDMainSortTestContext ctx = {nullptr};
-  test_lib_id_main_sort_init(&ctx);
+  LibIDMainSortTestContext ctx;
   EXPECT_TRUE(BLI_listbase_is_empty(&ctx.bmain->libraries));
 
   Library *lib_a = static_cast(BKE_id_new(ctx.bmain, ID_LI, "LI_A"));
@@ -130,29 +143,316 @@ TEST(lib_id_main_unique_name, linked_ids_1)
   ID *id_a = static_cast(BKE_id_new(ctx.bmain, ID_OB, "OB_A"));
   ID *id_b = static_cast(BKE_id_new(ctx.bmain, ID_OB, "OB_B"));
 
-  id_a->lib = lib_a;
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+
+  change_lib(ctx.bmain, id_a, lib_a);
   id_sort_by_name(&ctx.bmain->objects, id_a, nullptr);
-  id_b->lib = lib_a;
+  change_lib(ctx.bmain, id_b, lib_a);
   id_sort_by_name(&ctx.bmain->objects, id_b, nullptr);
-  BLI_strncpy(id_b->name, id_a->name, sizeof(id_b->name));
-  BKE_id_new_name_validate(&ctx.bmain->objects, id_b, nullptr, true);
-  EXPECT_TRUE(strcmp(id_b->name + 2, "OB_A.001") == 0);
-  EXPECT_TRUE(strcmp(id_a->name + 2, "OB_A") == 0);
+
+  change_name(ctx.bmain, id_b, "OB_A");
+  EXPECT_STREQ(id_b->name + 2, "OB_A.001");
+  EXPECT_STREQ(id_a->name + 2, "OB_A");
   EXPECT_TRUE(ctx.bmain->objects.first == id_c);
   EXPECT_TRUE(ctx.bmain->objects.last == id_b);
   test_lib_id_main_sort_check_order({id_c, id_a, id_b});
 
-  id_b->lib = lib_b;
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+
+  change_lib(ctx.bmain, id_b, lib_b);
   id_sort_by_name(&ctx.bmain->objects, id_b, nullptr);
-  BLI_strncpy(id_b->name, id_a->name, sizeof(id_b->name));
-  BKE_id_new_name_validate(&ctx.bmain->objects, id_b, nullptr, true);
-  EXPECT_TRUE(strcmp(id_b->name + 2, "OB_A") == 0);
-  EXPECT_TRUE(strcmp(id_a->name + 2, "OB_A") == 0);
+  change_name(ctx.bmain, id_b, "OB_A");
+  EXPECT_STREQ(id_b->name + 2, "OB_A");
+  EXPECT_STREQ(id_a->name + 2, "OB_A");
   EXPECT_TRUE(ctx.bmain->objects.first == id_c);
   EXPECT_TRUE(ctx.bmain->objects.last == id_b);
   test_lib_id_main_sort_check_order({id_c, id_a, id_b});
 
-  test_lib_id_main_sort_free(&ctx);
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+}
+
+TEST(lib_id_main_unique_name, ids_sorted_by_default)
+{
+  LibIDMainSortTestContext ctx;
+
+  ID *id_foo = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo"));
+  ID *id_bar = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Bar"));
+  ID *id_baz = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Baz"));
+  ID *id_yes = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Yes"));
+  test_lib_id_main_sort_check_order({id_bar, id_baz, id_foo, id_yes});
+
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+}
+
+static ID *add_id_in_library(Main *bmain, const char *name, Library *lib)
+{
+  ID *id = static_cast(BKE_id_new(bmain, ID_OB, name));
+  change_lib(bmain, id, lib);
+  id_sort_by_name(&bmain->objects, id, nullptr);
+  return id;
+}
+
+TEST(lib_id_main_unique_name, ids_sorted_by_default_with_libraries)
+{
+  LibIDMainSortTestContext ctx;
+
+  Library *lib_one = static_cast(BKE_id_new(ctx.bmain, ID_LI, "LibOne"));
+  Library *lib_two = static_cast(BKE_id_new(ctx.bmain, ID_LI, "LibTwo"));
+
+  ID *id_foo = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo"));
+  ID *id_bar = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Bar"));
+
+  ID *id_l1c = add_id_in_library(ctx.bmain, "C", lib_one);
+  ID *id_l2b = add_id_in_library(ctx.bmain, "B", lib_two);
+  ID *id_l1a = add_id_in_library(ctx.bmain, "A", lib_one);
+
+  ID *id_baz = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Baz"));
+  ID *id_yes = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Yes"));
+
+  test_lib_id_main_sort_check_order({id_bar, id_baz, id_foo, id_yes, id_l1a, id_l1c, id_l2b});
+
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+}
+
+TEST(lib_id_main_unique_name, name_too_long_handling)
+{
+  LibIDMainSortTestContext ctx;
+  const char *name_a = "Long_Name_That_Does_Not_Fit_Into_Max_Name_Limit_And_Should_Get_Truncated";
+  const char *name_b = "Another_Long_Name_That_Does_Not_Fit_And_Has_A_Number_Suffix.123456";
+  const char *name_c = "Name_That_Has_Too_Long_Number_Suffix.1234567890";
+
+  ID *id_a = static_cast(BKE_id_new(ctx.bmain, ID_OB, name_a));
+  ID *id_b = static_cast(BKE_id_new(ctx.bmain, ID_OB, name_b));
+  ID *id_c = static_cast(BKE_id_new(ctx.bmain, ID_OB, name_c));
+
+  EXPECT_STREQ(id_a->name + 2, "Long_Name_That_Does_Not_Fit_Into_Max_Name_Limit_And_Should_Get_");
+  EXPECT_STREQ(id_b->name + 2, "Another_Long_Name_That_Does_Not_Fit_And_Has_A_Number_Suffix.123");
+  EXPECT_STREQ(id_c->name + 2, "Name_That_Has_Too_Long_Number_Suffix.1234567890"); /* Unchanged */
+
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+}
+
+TEST(lib_id_main_unique_name, create_equivalent_numeric_suffixes)
+{
+  LibIDMainSortTestContext ctx;
+
+  /* Create names where many of their numeric suffixes are
+   * the same number, yet the names are different and thus
+   * should be allowed as-is. */
+  ID *id_a = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.123"));
+  ID *id_b = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.000"));
+  ID *id_c = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.003"));
+  ID *id_d = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.3"));
+  ID *id_e = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.0"));
+  ID *id_f = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo."));
+  ID *id_g = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.0123"));
+  ID *id_h = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo"));
+  ID *id_i = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.."));
+  ID *id_j = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo..001"));
+  ID *id_k = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo..000"));
+
+  EXPECT_STREQ(id_a->name + 2, "Foo.123");
+  EXPECT_STREQ(id_b->name + 2, "Foo.000");
+  EXPECT_STREQ(id_c->name + 2, "Foo.003");
+  EXPECT_STREQ(id_d->name + 2, "Foo.3");
+  EXPECT_STREQ(id_e->name + 2, "Foo.0");
+  EXPECT_STREQ(id_f->name + 2, "Foo.");
+  EXPECT_STREQ(id_g->name + 2, "Foo.0123");
+  EXPECT_STREQ(id_h->name + 2, "Foo");
+  EXPECT_STREQ(id_i->name + 2, "Foo..");
+  EXPECT_STREQ(id_j->name + 2, "Foo..001");
+  EXPECT_STREQ(id_k->name + 2, "Foo..000");
+
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+
+  /* Now create their exact duplicates again, and check what happens. */
+  id_a = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.123"));
+  id_b = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.000"));
+  id_c = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.003"));
+  id_d = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.3"));
+  id_e = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.0"));
+  id_f = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo."));
+  id_g = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.0123"));
+  id_h = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo"));
+  id_i = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.."));
+  id_j = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo..001"));
+  id_k = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo..000"));
+
+  EXPECT_STREQ(id_a->name + 2, "Foo.001");
+  EXPECT_STREQ(id_b->name + 2, "Foo.002");
+  EXPECT_STREQ(id_c->name + 2, "Foo.004");
+  EXPECT_STREQ(id_d->name + 2, "Foo.005");
+  EXPECT_STREQ(id_e->name + 2, "Foo.006");
+  EXPECT_STREQ(id_f->name + 2, "Foo..002");
+  EXPECT_STREQ(id_g->name + 2, "Foo.007");
+  EXPECT_STREQ(id_h->name + 2, "Foo.008");
+  EXPECT_STREQ(id_i->name + 2, "Foo...001");
+  EXPECT_STREQ(id_j->name + 2, "Foo..003");
+  EXPECT_STREQ(id_k->name + 2, "Foo..004");
+
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+}
+
+TEST(lib_id_main_unique_name, zero_suffix_is_never_assigned)
+{
+  LibIDMainSortTestContext ctx;
+
+  /* Creating these should assign 002 to the first one, but the next
+   * ones should start numbers starting from 1: 001 and 003. */
+  ID *id_002 = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.002"));
+  ID *id_001 = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.002"));
+  ID *id_003 = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.002"));
+
+  EXPECT_STREQ(id_002->name + 2, "Foo.002");
+  EXPECT_STREQ(id_001->name + 2, "Foo.001");
+  EXPECT_STREQ(id_003->name + 2, "Foo.003");
+
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+}
+
+TEST(lib_id_main_unique_name, remove_after_dup_get_original_name)
+{
+  LibIDMainSortTestContext ctx;
+
+  ID *id_a = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo"));
+  ID *id_b = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo"));
+
+  EXPECT_STREQ(id_a->name + 2, "Foo");
+  EXPECT_STREQ(id_b->name + 2, "Foo.001");
+  BKE_id_free(ctx.bmain, id_a);
+
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+
+  id_a = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo"));
+  EXPECT_STREQ(id_a->name + 2, "Foo");
+
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+}
+
+TEST(lib_id_main_unique_name, name_number_suffix_assignment)
+{
+  LibIDMainSortTestContext ctx;
+
+  /* Create <1k objects first. */
+  const int total_object_count = 1200;
+  ID *ids[total_object_count] = {};
+  for (int i = 0; i < total_object_count / 2; ++i) {
+    ids[i] = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo"));
+  }
+
+  /* They should get assigned sequential numeric suffixes. */
+  EXPECT_STREQ(ids[0]->name + 2, "Foo");
+  EXPECT_STREQ(ids[1]->name + 2, "Foo.001");
+  EXPECT_STREQ(ids[total_object_count / 2 - 1]->name + 2, "Foo.599");
+
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+
+  /* Free some of the objects. */
+  BKE_id_free(ctx.bmain, ids[10]);
+  BKE_id_free(ctx.bmain, ids[20]);
+  BKE_id_free(ctx.bmain, ids[30]);
+
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+
+  /* Create objects again; they should get suffixes that were just free'd up. */
+  ID *id_010 = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo"));
+  EXPECT_STREQ(id_010->name + 2, "Foo.010");
+  ID *id_020 = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.123"));
+  EXPECT_STREQ(id_020->name + 2, "Foo.020");
+  /* Suffixes >1k do not get the "use the most proper free one" treatment. */
+  ID *id_2000 = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.2000"));
+  EXPECT_STREQ(id_2000->name + 2, "Foo.2000");
+  /* But smaller than 1k suffixes do get proper empty spots. */
+  ID *id_030 = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo"));
+  EXPECT_STREQ(id_030->name + 2, "Foo.030");
+  ID *id_600 = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo"));
+  EXPECT_STREQ(id_600->name + 2, "Foo.600");
+
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+
+  /* Max possible numeric suffix. */
+  ID *id_max = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.999999999"));
+  EXPECT_STREQ(id_max->name + 2, "Foo.999999999");
+  /* Try with max. possible suffix again: will assign free suffix under 1k. */
+  ID *id_max1 = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.999999999"));
+  EXPECT_STREQ(id_max1->name + 2, "Foo.601");
+
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+
+  /* Now create the rest of objects, to use all the suffixes up to 1k.
+   * Once all the ones up to 1k are used, the logic will fall back to
+   * "use largest number seen + 1", but the largest one is already the max
+   * possible. So it will shorten the name part and restart the counter,
+   * i.e. "Fo.001". */
+  for (int i = total_object_count / 2; i < total_object_count; ++i) {
+    ids[i] = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo"));
+  }
+  /* At this point creating "Foo" based objects will fall always
+   * result in shortened name to "Fo". */
+  ID *id_fo178 = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo"));
+  EXPECT_STREQ(id_fo178->name + 2, "Fo.178");
+  ID *id_fo179 = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.2000"));
+  EXPECT_STREQ(id_fo179->name + 2, "Fo.179");
+  ID *id_fo180 = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo.999999999"));
+  EXPECT_STREQ(id_fo180->name + 2, "Fo.180");
+
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+}
+
+TEST(lib_id_main_unique_name, renames_with_duplicates)
+{
+  LibIDMainSortTestContext ctx;
+
+  ID *id_a = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo"));
+  ID *id_b = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo"));
+  ID *id_c = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Bar"));
+
+  EXPECT_STREQ(id_a->name + 2, "Foo");
+  EXPECT_STREQ(id_b->name + 2, "Foo.001");
+  EXPECT_STREQ(id_c->name + 2, "Bar");
+
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+
+  BKE_libblock_rename(ctx.bmain, id_a, "Foo.002");
+  EXPECT_STREQ(id_a->name + 2, "Foo.002");
+  BKE_libblock_rename(ctx.bmain, id_b, "Bar");
+  EXPECT_STREQ(id_b->name + 2, "Bar.001");
+  BKE_libblock_rename(ctx.bmain, id_c, "Foo");
+  EXPECT_STREQ(id_c->name + 2, "Foo");
+  BKE_libblock_rename(ctx.bmain, id_b, "Bar");
+  EXPECT_STREQ(id_b->name + 2, "Bar");
+
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+}
+
+TEST(lib_id_main_unique_name, names_are_unique_per_id_type)
+{
+  LibIDMainSortTestContext ctx;
+
+  ID *id_a = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo"));
+  ID *id_b = static_cast(BKE_id_new(ctx.bmain, ID_CA, "Foo"));
+  ID *id_c = static_cast(BKE_id_new(ctx.bmain, ID_OB, "Foo"));
+
+  EXPECT_STREQ(id_a->name + 2, "Foo");
+  EXPECT_STREQ(id_b->name + 2, "Foo"); /* Different types (OB & CA) can have the same name. */
+  EXPECT_STREQ(id_c->name + 2, "Foo.001");
+
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
+}
+
+TEST(lib_id_main_unique_name, name_huge_number_suffix)
+{
+  LibIDMainSortTestContext ctx;
+
+  /* Use numeric suffix that is really large: should come through
+   * fine, since no duplicates with other names. */
+  ID *id_a = static_cast(BKE_id_new(ctx.bmain, ID_OB, "SuperLong.1234567890"));
+  EXPECT_STREQ(id_a->name + 2, "SuperLong.1234567890");
+  /* Now create with the same name again: should get 001 suffix. */
+  ID *id_b = static_cast(BKE_id_new(ctx.bmain, ID_OB, "SuperLong.1234567890"));
+  EXPECT_STREQ(id_b->name + 2, "SuperLong.001");
+
+  EXPECT_TRUE(BKE_main_namemap_validate(ctx.bmain));
 }
 
 }  // namespace blender::bke::tests
diff --git a/source/blender/blenkernel/intern/lib_override.cc b/source/blender/blenkernel/intern/lib_override.cc
index d816b5ede5f..3f1b80014ac 100644
--- a/source/blender/blenkernel/intern/lib_override.cc
+++ b/source/blender/blenkernel/intern/lib_override.cc
@@ -34,6 +34,7 @@
 #include "BKE_lib_query.h"
 #include "BKE_lib_remap.h"
 #include "BKE_main.h"
+#include "BKE_main_namemap.h"
 #include "BKE_node.h"
 #include "BKE_report.h"
 #include "BKE_scene.h"
@@ -51,6 +52,7 @@
 #include "PIL_time.h"
 
 #include "RNA_access.h"
+#include "RNA_path.h"
 #include "RNA_prototypes.h"
 #include "RNA_types.h"
 
@@ -80,8 +82,8 @@ static void lib_override_library_property_operation_clear(
 BLI_INLINE void lib_override_object_posemode_transfer(ID *id_dst, ID *id_src)
 {
   if (GS(id_src->name) == ID_OB && GS(id_dst->name) == ID_OB) {
-    Object *ob_src = (Object *)id_src;
-    Object *ob_dst = (Object *)id_dst;
+    Object *ob_src = reinterpret_cast(id_src);
+    Object *ob_dst = reinterpret_cast(id_dst);
     if (ob_src->type == OB_ARMATURE && (ob_src->mode & OB_MODE_POSE) != 0) {
       ob_dst->restore_mode = ob_dst->mode;
       ob_dst->mode |= OB_MODE_POSE;
@@ -90,36 +92,38 @@ BLI_INLINE void lib_override_object_posemode_transfer(ID *id_dst, ID *id_src)
 }
 
 /** Get override data for a given ID. Needed because of our beloved shape keys snowflake. */
-BLI_INLINE const IDOverrideLibrary *lib_override_get(const Main *bmain,
-                                                     const ID *id,
-                                                     const ID **r_owner_id)
+BLI_INLINE const IDOverrideLibrary *BKE_lib_override_library_get(const Main * /*bmain*/,
+                                                                 const ID *id,
+                                                                 const ID * /*owner_id_hint*/,
+                                                                 const ID **r_owner_id)
 {
-  if (r_owner_id != nullptr) {
-    *r_owner_id = id;
-  }
   if (id->flag & LIB_EMBEDDED_DATA_LIB_OVERRIDE) {
-    const IDTypeInfo *id_type = BKE_idtype_get_info_from_id(id);
-    if (id_type->owner_get != nullptr) {
-      /* The #IDTypeInfo::owner_get callback should not modify the arguments, so casting away const
-       * is okay. */
-      const ID *owner_id = id_type->owner_get(const_cast
(bmain), const_cast(id));
-      if (r_owner_id != nullptr) {
-        *r_owner_id = owner_id;
-      }
-      return owner_id->override_library;
+    const ID *owner_id = BKE_id_owner_get(const_cast(id));
+    BLI_assert_msg(owner_id != nullptr, "Liboverride-embedded ID with no owner");
+    if (r_owner_id != nullptr) {
+      *r_owner_id = owner_id;
     }
-    BLI_assert_msg(0, "IDTypeInfo of liboverride-embedded ID with no owner getter");
+    return owner_id->override_library;
+  }
+
+  if (r_owner_id != nullptr) {
+    *r_owner_id = id;
   }
   return id->override_library;
 }
 
-BLI_INLINE IDOverrideLibrary *lib_override_get(Main *bmain, ID *id, ID **r_owner_id)
+IDOverrideLibrary *BKE_lib_override_library_get(Main *bmain,
+                                                ID *id,
+                                                ID *owner_id_hint,
+                                                ID **r_owner_id)
 {
   /* Reuse the implementation of the const access function, which does not change the arguments.
    * Add const explicitly to make it clear to the compiler to avoid just calling this function. */
-  return const_cast(lib_override_get(const_cast(bmain),
-                                                          const_cast(id),
-                                                          const_cast(r_owner_id)));
+  return const_cast(
+      BKE_lib_override_library_get(const_cast(bmain),
+                                   const_cast(id),
+                                   const_cast(owner_id_hint),
+                                   const_cast(r_owner_id)));
 }
 
 IDOverrideLibrary *BKE_lib_override_library_init(ID *local_id, ID *reference_id)
@@ -184,7 +188,7 @@ void BKE_lib_override_library_copy(ID *dst_id, const ID *src_id, const bool do_f
    * Otherwise, source is only an override template, it then becomes reference of dest ID. */
   dst_id->override_library->reference = src_id->override_library->reference ?
                                             src_id->override_library->reference :
-                                            (ID *)src_id;
+                                            const_cast(src_id);
   id_us_plus(dst_id->override_library->reference);
 
   dst_id->override_library->hierarchy_root = src_id->override_library->hierarchy_root;
@@ -316,7 +320,7 @@ bool BKE_lib_override_library_is_system_defined(const Main *bmain, const ID *id)
 {
   if (ID_IS_OVERRIDE_LIBRARY(id)) {
     const ID *override_owner_id;
-    lib_override_get(bmain, id, &override_owner_id);
+    BKE_lib_override_library_get(bmain, id, nullptr, &override_owner_id);
     return (override_owner_id->override_library->flag & IDOVERRIDE_LIBRARY_FLAG_SYSTEM_DEFINED) !=
            0;
   }
@@ -357,6 +361,10 @@ static int foreachid_is_hierarchy_leaf_fn(LibraryIDLinkCallbackData *cb_data)
   ID *id = *cb_data->id_pointer;
   bool *is_leaf = static_cast(cb_data->user_data);
 
+  if (cb_data->cb_flag & IDWALK_CB_LOOPBACK) {
+    return IDWALK_RET_NOP;
+  }
+
   if (id != nullptr && ID_IS_OVERRIDE_LIBRARY_REAL(id) &&
       id->override_library->hierarchy_root == id_owner->override_library->hierarchy_root) {
     *is_leaf = false;
@@ -428,14 +436,42 @@ static void lib_override_prefill_newid_from_existing_overrides(Main *bmain, ID *
 {
   ID *id_iter;
   FOREACH_MAIN_ID_BEGIN (bmain, id_iter) {
-    if (ID_IS_OVERRIDE_LIBRARY_REAL(id_iter) &&
-        id_iter->override_library->hierarchy_root == id_hierarchy_root) {
-      id_iter->override_library->reference->newid = id_iter;
+    ID *id = id_iter;
+    if (GS(id_iter->name) == ID_KE) {
+      id = reinterpret_cast(id_iter)->from;
+      BLI_assert(id != nullptr);
+    }
+    if (ID_IS_OVERRIDE_LIBRARY_REAL(id) &&
+        id->override_library->hierarchy_root == id_hierarchy_root) {
+      id->override_library->reference->newid = id;
+      if (GS(id_iter->name) == ID_KE) {
+        Key *reference_key = BKE_key_from_id(id->override_library->reference);
+        if (reference_key != nullptr) {
+          reference_key->id.newid = id_iter;
+        }
+      }
     }
   }
   FOREACH_MAIN_ID_END;
 }
 
+static void lib_override_remapper_overrides_add(IDRemapper *id_remapper,
+                                                ID *reference_id,
+                                                ID *local_id)
+{
+  BKE_id_remapper_add(id_remapper, reference_id, local_id);
+
+  Key *reference_key, *local_key = nullptr;
+  if ((reference_key = BKE_key_from_id(reference_id)) != nullptr) {
+    if (reference_id->newid != nullptr) {
+      local_key = BKE_key_from_id(reference_id->newid);
+      BLI_assert(local_key != nullptr);
+    }
+
+    BKE_id_remapper_add(id_remapper, &reference_key->id, &local_key->id);
+  }
+}
+
 /* TODO: Make this static local function instead? API is becoming complex, and it's not used
  * outside of this file anyway. */
 bool BKE_lib_override_library_create_from_tag(Main *bmain,
@@ -544,6 +580,7 @@ bool BKE_lib_override_library_create_from_tag(Main *bmain,
     BLI_assert(id_hierarchy_root != nullptr);
 
     LinkNode *relinked_ids = nullptr;
+    IDRemapper *id_remapper = BKE_id_remapper_create();
     /* Still checking the whole Main, that way we can tag other local IDs as needing to be
      * remapped to use newly created overriding IDs, if needed. */
     ID *id;
@@ -568,6 +605,14 @@ bool BKE_lib_override_library_create_from_tag(Main *bmain,
        * consider we should also relink it, as part of recursive resync. */
       if ((other_id->tag & LIB_TAG_DOIT) != 0 && other_id->lib != id_root_reference->lib) {
         BLI_linklist_prepend(&relinked_ids, other_id);
+        if (ID_IS_OVERRIDE_LIBRARY_REAL(other_id) &&
+            other_id->override_library->hierarchy_root == id_hierarchy_root) {
+          reference_id = other_id->override_library->reference;
+          ID *local_id = reference_id->newid;
+          if (other_id == local_id) {
+            lib_override_remapper_overrides_add(id_remapper, reference_id, local_id);
+          }
+        }
       }
       if (other_id != id) {
         other_id->lib = id_root_reference->lib;
@@ -575,7 +620,6 @@ bool BKE_lib_override_library_create_from_tag(Main *bmain,
     }
     FOREACH_MAIN_ID_END;
 
-    IDRemapper *id_remapper = BKE_id_remapper_create();
     for (todo_id_iter = static_cast(todo_ids.first); todo_id_iter != nullptr;
          todo_id_iter = todo_id_iter->next) {
       reference_id = static_cast(todo_id_iter->data);
@@ -587,15 +631,7 @@ bool BKE_lib_override_library_create_from_tag(Main *bmain,
 
       local_id->override_library->hierarchy_root = id_hierarchy_root;
 
-      BKE_id_remapper_add(id_remapper, reference_id, local_id);
-
-      Key *reference_key, *local_key = nullptr;
-      if ((reference_key = BKE_key_from_id(reference_id)) != nullptr) {
-        local_key = BKE_key_from_id(reference_id->newid);
-        BLI_assert(local_key != nullptr);
-
-        BKE_id_remapper_add(id_remapper, &reference_key->id, &local_key->id);
-      }
+      lib_override_remapper_overrides_add(id_remapper, reference_id, local_id);
     }
 
     BKE_libblock_relink_multiple(bmain,
@@ -652,7 +688,7 @@ static void lib_override_group_tag_data_object_to_collection_init_collection_pro
     LinkNodePair **collections_linkedlist_p;
     if (!BLI_ghash_ensure_p(data->linked_object_to_instantiating_collections,
                             ob,
-                            (void ***)&collections_linkedlist_p)) {
+                            reinterpret_cast(&collections_linkedlist_p))) {
       *collections_linkedlist_p = static_cast(
           BLI_memarena_calloc(data->mem_arena, sizeof(**collections_linkedlist_p)));
     }
@@ -693,7 +729,7 @@ static void lib_override_hierarchy_dependencies_recursive_tag_from(LibOverrideGr
   ID *id = data->id_root;
   const bool is_override = data->is_override;
 
-  if ((*(uint *)&id->tag & data->tag) == 0) {
+  if ((*reinterpret_cast(&id->tag) & data->tag) == 0) {
     /* This ID is not tagged, no reason to proceed further to its parents. */
     return;
   }
@@ -751,7 +787,7 @@ static bool lib_override_hierarchy_dependencies_recursive_tag(LibOverrideGroupTa
 
   if (entry->tags & MAINIDRELATIONS_ENTRY_TAGS_PROCESSED_TO) {
     /* This ID has already been processed. */
-    return (*(uint *)&id->tag & data->tag) != 0;
+    return (*reinterpret_cast(&id->tag) & data->tag) != 0;
   }
   /* This way we won't process again that ID, should we encounter it again through another
    * relationship hierarchy. */
@@ -784,11 +820,11 @@ static bool lib_override_hierarchy_dependencies_recursive_tag(LibOverrideGroupTa
    *
    * This will cover e.g. the case where user override an armature, and would expect the mesh
    * object deformed by that armature to also be overridden. */
-  if ((*(uint *)&id->tag & data->tag) != 0 && !is_resync) {
+  if ((*reinterpret_cast(&id->tag) & data->tag) != 0 && !is_resync) {
     lib_override_hierarchy_dependencies_recursive_tag_from(data);
   }
 
-  return (*(uint *)&id->tag & data->tag) != 0;
+  return (*reinterpret_cast(&id->tag) & data->tag) != 0;
 }
 
 static void lib_override_linked_group_tag_recursive(LibOverrideGroupTagData *data)
@@ -1055,8 +1091,10 @@ static void lib_override_overrides_group_tag_recursive(LibOverrideGroupTagData *
       continue;
     }
 
-    const Library *reference_lib = lib_override_get(bmain, id_owner, nullptr)->reference->lib;
-    const ID *to_id_reference = lib_override_get(bmain, to_id, nullptr)->reference;
+    const Library *reference_lib =
+        BKE_lib_override_library_get(bmain, id_owner, nullptr, nullptr)->reference->lib;
+    const ID *to_id_reference =
+        BKE_lib_override_library_get(bmain, to_id, nullptr, nullptr)->reference;
     if (to_id_reference->lib != reference_lib) {
       /* We do not override data-blocks from other libraries, nor do we process them. */
       continue;
@@ -1121,14 +1159,26 @@ static bool lib_override_library_create_do(Main *bmain,
   BKE_main_relations_tag_set(bmain, MAINIDRELATIONS_ENTRY_TAGS_PROCESSED, false);
   lib_override_hierarchy_dependencies_recursive_tag(&data);
 
+  /* In case the operation is on an already partially overridden hierarchy, all existing overrides
+   * in that hierarchy need to be tagged for remapping from linked reference ID usages to newly
+   * created overrides ones. */
+  if (id_hierarchy_root_reference->lib != id_root_reference->lib) {
+    BLI_assert(ID_IS_OVERRIDE_LIBRARY_REAL(id_hierarchy_root_reference));
+    BLI_assert(id_hierarchy_root_reference->override_library->reference->lib ==
+               id_root_reference->lib);
+
+    BKE_main_relations_tag_set(bmain, MAINIDRELATIONS_ENTRY_TAGS_PROCESSED, false);
+    data.hierarchy_root_id = id_hierarchy_root_reference;
+    data.id_root = id_hierarchy_root_reference;
+    data.is_override = true;
+    lib_override_overrides_group_tag(&data);
+  }
+
   BKE_main_relations_free(bmain);
   lib_override_group_tag_data_clear(&data);
 
   bool success = false;
   if (id_hierarchy_root_reference->lib != id_root_reference->lib) {
-    BLI_assert(ID_IS_OVERRIDE_LIBRARY_REAL(id_hierarchy_root_reference));
-    BLI_assert(id_hierarchy_root_reference->override_library->reference->lib ==
-               id_root_reference->lib);
     success = BKE_lib_override_library_create_from_tag(bmain,
                                                        owner_library,
                                                        id_root_reference,
@@ -1157,6 +1207,7 @@ static void lib_override_library_create_post_process(Main *bmain,
                                                      ID *id_root,
                                                      ID *id_instance_hint,
                                                      Collection *residual_storage,
+                                                     const Object *old_active_object,
                                                      const bool is_resync)
 {
   /* NOTE: We only care about local IDs here, if a linked object is not instantiated in any way we
@@ -1180,9 +1231,9 @@ static void lib_override_library_create_post_process(Main *bmain,
     switch (GS(id_root->name)) {
       case ID_GR: {
         Object *ob_reference = id_instance_hint != nullptr && GS(id_instance_hint->name) == ID_OB ?
-                                   (Object *)id_instance_hint :
+                                   reinterpret_cast(id_instance_hint) :
                                    nullptr;
-        Collection *collection_new = ((Collection *)id_root->newid);
+        Collection *collection_new = (reinterpret_cast(id_root->newid));
         if (is_resync && BKE_collection_is_in_scene(collection_new)) {
           break;
         }
@@ -1192,11 +1243,11 @@ static void lib_override_library_create_post_process(Main *bmain,
         else if (id_instance_hint != nullptr) {
           BLI_assert(GS(id_instance_hint->name) == ID_GR);
           BKE_collection_add_from_collection(
-              bmain, scene, ((Collection *)id_instance_hint), collection_new);
+              bmain, scene, (reinterpret_cast(id_instance_hint)), collection_new);
         }
         else {
           BKE_collection_add_from_collection(
-              bmain, scene, ((Collection *)id_root), collection_new);
+              bmain, scene, (reinterpret_cast(id_root)), collection_new);
         }
 
         BLI_assert(BKE_collection_is_in_scene(collection_new));
@@ -1205,9 +1256,10 @@ static void lib_override_library_create_post_process(Main *bmain,
         break;
       }
       case ID_OB: {
-        Object *ob_new = (Object *)id_root->newid;
+        Object *ob_new = reinterpret_cast(id_root->newid);
         if (BLI_gset_lookup(all_objects_in_scene, ob_new) == nullptr) {
-          BKE_collection_object_add_from(bmain, scene, (Object *)id_root, ob_new);
+          BKE_collection_object_add_from(
+              bmain, scene, reinterpret_cast(id_root), ob_new);
           all_objects_in_scene = BKE_scene_objects_as_gset(scene, all_objects_in_scene);
         }
         break;
@@ -1217,10 +1269,12 @@ static void lib_override_library_create_post_process(Main *bmain,
     }
   }
 
+  BKE_view_layer_synced_ensure(scene, view_layer);
+
   /* We need to ensure all new overrides of objects are properly instantiated. */
   Collection *default_instantiating_collection = residual_storage;
   LISTBASE_FOREACH (Object *, ob, &bmain->objects) {
-    Object *ob_new = (Object *)ob->id.newid;
+    Object *ob_new = reinterpret_cast(ob->id.newid);
     if (ob_new == nullptr || (ID_IS_LINKED(ob_new) && ob_new->id.lib != owner_library)) {
       continue;
     }
@@ -1228,6 +1282,14 @@ static void lib_override_library_create_post_process(Main *bmain,
     BLI_assert(ob_new->id.override_library != nullptr &&
                ob_new->id.override_library->reference == &ob->id);
 
+    if (old_active_object == ob) {
+      Base *basact = BKE_view_layer_base_find(view_layer, ob_new);
+      if (basact != nullptr) {
+        view_layer->basact = basact;
+      }
+      DEG_id_tag_update(&scene->id, ID_RECALC_SELECT);
+    }
+
     if (BLI_gset_lookup(all_objects_in_scene, ob_new) == nullptr) {
       if (id_root != nullptr && default_instantiating_collection == nullptr) {
         ID *id_ref = id_root->newid != nullptr ? id_root->newid : id_root;
@@ -1254,7 +1316,7 @@ static void lib_override_library_create_post_process(Main *bmain,
           case ID_OB: {
             /* Add the other objects to one of the collections instantiating the
              * root object, or scene's master collection if none found. */
-            Object *ob_ref = (Object *)id_ref;
+            Object *ob_ref = reinterpret_cast(id_ref);
             LISTBASE_FOREACH (Collection *, collection, &bmain->collections) {
               if (BKE_collection_has_object(collection, ob_ref) &&
                   (view_layer != nullptr ?
@@ -1284,8 +1346,10 @@ static void lib_override_library_create_post_process(Main *bmain,
     ID *id_ref = id_root->newid != nullptr ? id_root->newid : id_root;
     switch (GS(id_ref->name)) {
       case ID_GR:
-        BKE_collection_add_from_collection(
-            bmain, scene, (Collection *)id_ref, default_instantiating_collection);
+        BKE_collection_add_from_collection(bmain,
+                                           scene,
+                                           reinterpret_cast(id_ref),
+                                           default_instantiating_collection);
         break;
       default:
         /* Add to master collection. */
@@ -1315,6 +1379,8 @@ bool BKE_lib_override_library_create(Main *bmain,
   if (id_hierarchy_root_reference == nullptr) {
     id_hierarchy_root_reference = id_root_reference;
   }
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  const Object *old_active_object = BKE_view_layer_active_object_get(view_layer);
 
   const bool success = lib_override_library_create_do(bmain,
                                                       scene,
@@ -1338,6 +1404,7 @@ bool BKE_lib_override_library_create(Main *bmain,
                                            id_root_reference,
                                            id_instance_hint,
                                            nullptr,
+                                           old_active_object,
                                            false);
 
   /* Cleanup. */
@@ -1392,7 +1459,7 @@ static ID *lib_override_root_find(Main *bmain, ID *id, const int curr_level, int
     BLI_assert(id->flag & LIB_EMBEDDED_DATA_LIB_OVERRIDE);
     ID *id_owner;
     int best_level_placeholder = 0;
-    lib_override_get(bmain, id, &id_owner);
+    BKE_lib_override_library_get(bmain, id, nullptr, &id_owner);
     return lib_override_root_find(bmain, id_owner, curr_level + 1, &best_level_placeholder);
   }
   /* This way we won't process again that ID, should we encounter it again through another
@@ -1431,7 +1498,7 @@ static ID *lib_override_root_find(Main *bmain, ID *id, const int curr_level, int
     BLI_assert(id->flag & LIB_EMBEDDED_DATA_LIB_OVERRIDE);
     ID *id_owner;
     int best_level_placeholder = 0;
-    lib_override_get(bmain, best_root_id_candidate, &id_owner);
+    BKE_lib_override_library_get(bmain, best_root_id_candidate, nullptr, &id_owner);
     best_root_id_candidate = lib_override_root_find(
         bmain, id_owner, curr_level + 1, &best_level_placeholder);
   }
@@ -1651,6 +1718,8 @@ static bool lib_override_library_resync(Main *bmain,
 
   ID *id_root_reference = id_root->override_library->reference;
   ID *id;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  const Object *old_active_object = BKE_view_layer_active_object_get(view_layer);
 
   if (id_root_reference->tag & LIB_TAG_MISSING) {
     BKE_reportf(reports != nullptr ? reports->reports : nullptr,
@@ -1731,6 +1800,10 @@ static bool lib_override_library_resync(Main *bmain,
     lib_override_hierarchy_dependencies_recursive_tag(&data);
 
     FOREACH_MAIN_ID_BEGIN (bmain, id) {
+      if ((id->lib != id_root->lib) || !ID_IS_OVERRIDE_LIBRARY(id)) {
+        continue;
+      }
+
       /* IDs that get fully removed from linked data remain as local overrides (using place-holder
        * linked IDs as reference), but they are often not reachable from any current valid local
        * override hierarchy anymore. This will ensure they get properly deleted at the end of this
@@ -1744,62 +1817,67 @@ static bool lib_override_library_resync(Main *bmain,
         id->tag |= LIB_TAG_MISSING;
       }
 
-      if ((id->lib == id_root->lib) && ID_IS_OVERRIDE_LIBRARY(id)) {
-        /* While this should not happen in typical cases (and won't be properly supported here),
-         * user is free to do all kind of very bad things, including having different local
-         * overrides of a same linked ID in a same hierarchy. */
-        IDOverrideLibrary *id_override_library = lib_override_get(bmain, id, nullptr);
+      /* While this should not happen in typical cases (and won't be properly supported here),
+       * user is free to do all kind of very bad things, including having different local
+       * overrides of a same linked ID in a same hierarchy. */
+      IDOverrideLibrary *id_override_library = BKE_lib_override_library_get(
+          bmain, id, nullptr, nullptr);
 
-        if (id_override_library->hierarchy_root != id_root->override_library->hierarchy_root) {
-          continue;
+      if (id_override_library->hierarchy_root != id_root->override_library->hierarchy_root) {
+        continue;
+      }
+
+      ID *reference_id = id_override_library->reference;
+      if (GS(reference_id->name) != GS(id->name)) {
+        switch (GS(id->name)) {
+          case ID_KE:
+            reference_id = reinterpret_cast(BKE_key_from_id(reference_id));
+            break;
+          case ID_GR:
+            BLI_assert(GS(reference_id->name) == ID_SCE);
+            reference_id = reinterpret_cast(
+                reinterpret_cast(reference_id)->master_collection);
+            break;
+          case ID_NT:
+            reference_id = reinterpret_cast(ntreeFromID(id));
+            break;
+          default:
+            break;
         }
+      }
+      if (reference_id == nullptr) {
+        /* Can happen e.g. when there is a local override of a shape-key, but the matching linked
+         * obdata (mesh etc.) does not have any shape-key anymore. */
+        continue;
+      }
+      BLI_assert(GS(reference_id->name) == GS(id->name));
 
-        ID *reference_id = id_override_library->reference;
-        if (GS(reference_id->name) != GS(id->name)) {
-          switch (GS(id->name)) {
-            case ID_KE:
-              reference_id = (ID *)BKE_key_from_id(reference_id);
-              break;
-            case ID_GR:
-              BLI_assert(GS(reference_id->name) == ID_SCE);
-              reference_id = (ID *)((Scene *)reference_id)->master_collection;
-              break;
-            case ID_NT:
-              reference_id = (ID *)ntreeFromID(id);
-              break;
-            default:
-              break;
-          }
+      if (!BLI_ghash_haskey(linkedref_to_old_override, reference_id)) {
+        BLI_ghash_insert(linkedref_to_old_override, reference_id, id);
+        if (!ID_IS_OVERRIDE_LIBRARY_REAL(id) || (id->tag & LIB_TAG_DOIT) == 0) {
+          continue;
         }
-        BLI_assert(GS(reference_id->name) == GS(id->name));
+        if ((id->override_library->reference->tag & LIB_TAG_DOIT) == 0) {
+          /* We have an override, but now it does not seem to be necessary to override that ID
+           * anymore. Check if there are some actual overrides from the user, otherwise assume
+           * that we can get rid of this local override. */
+          LISTBASE_FOREACH (IDOverrideLibraryProperty *, op, &id->override_library->properties) {
+            if (!ELEM(op->rna_prop_type, PROP_POINTER, PROP_COLLECTION)) {
+              id->override_library->reference->tag |= LIB_TAG_DOIT;
+              break;
+            }
 
-        if (!BLI_ghash_haskey(linkedref_to_old_override, reference_id)) {
-          BLI_ghash_insert(linkedref_to_old_override, reference_id, id);
-          if (!ID_IS_OVERRIDE_LIBRARY_REAL(id) || (id->tag & LIB_TAG_DOIT) == 0) {
-            continue;
-          }
-          if ((id->override_library->reference->tag & LIB_TAG_DOIT) == 0) {
-            /* We have an override, but now it does not seem to be necessary to override that ID
-             * anymore. Check if there are some actual overrides from the user, otherwise assume
-             * that we can get rid of this local override. */
-            LISTBASE_FOREACH (IDOverrideLibraryProperty *, op, &id->override_library->properties) {
-              if (!ELEM(op->rna_prop_type, PROP_POINTER, PROP_COLLECTION)) {
+            bool do_break = false;
+            LISTBASE_FOREACH (IDOverrideLibraryPropertyOperation *, opop, &op->operations) {
+              if ((opop->flag & IDOVERRIDE_LIBRARY_FLAG_IDPOINTER_MATCH_REFERENCE) == 0) {
                 id->override_library->reference->tag |= LIB_TAG_DOIT;
-                break;
-              }
-
-              bool do_break = false;
-              LISTBASE_FOREACH (IDOverrideLibraryPropertyOperation *, opop, &op->operations) {
-                if ((opop->flag & IDOVERRIDE_LIBRARY_FLAG_IDPOINTER_MATCH_REFERENCE) == 0) {
-                  id->override_library->reference->tag |= LIB_TAG_DOIT;
-                  do_break = true;
-                  break;
-                }
-              }
-              if (do_break) {
+                do_break = true;
                 break;
               }
             }
+            if (do_break) {
+              break;
+            }
           }
         }
       }
@@ -1841,60 +1919,62 @@ static bool lib_override_library_resync(Main *bmain,
   ListBase *lb;
   FOREACH_MAIN_LISTBASE_BEGIN (bmain, lb) {
     FOREACH_MAIN_LISTBASE_ID_BEGIN (lb, id) {
-      if (id->tag & LIB_TAG_DOIT && id->newid != nullptr && id->lib == id_root_reference->lib) {
-        ID *id_override_new = id->newid;
-        ID *id_override_old = static_cast(BLI_ghash_lookup(linkedref_to_old_override, id));
+      if ((id->tag & LIB_TAG_DOIT) == 0 || id->newid == nullptr ||
+          id->lib != id_root_reference->lib) {
+        continue;
+      }
+      ID *id_override_new = id->newid;
+      ID *id_override_old = static_cast(BLI_ghash_lookup(linkedref_to_old_override, id));
 
-        BLI_assert((id_override_new->tag & LIB_TAG_LIB_OVERRIDE_NEED_RESYNC) == 0);
-
-        /* We need to 'move back' newly created override into its proper library (since it was
-         * duplicated from the reference ID with 'no main' option, it should currently be the same
-         * as the reference ID one). */
-        BLI_assert(/*!ID_IS_LINKED(id_override_new) || */ id_override_new->lib == id->lib);
-        BLI_assert(id_override_old == nullptr || id_override_old->lib == id_root->lib);
-        id_override_new->lib = id_root->lib;
-        /* Remap step below will tag directly linked ones properly as needed. */
-        if (ID_IS_LINKED(id_override_new)) {
-          id_override_new->tag |= LIB_TAG_INDIRECT;
-        }
+      BLI_assert((id_override_new->tag & LIB_TAG_LIB_OVERRIDE_NEED_RESYNC) == 0);
+
+      /* We need to 'move back' newly created override into its proper library (since it was
+       * duplicated from the reference ID with 'no main' option, it should currently be the same
+       * as the reference ID one). */
+      BLI_assert(/*!ID_IS_LINKED(id_override_new) || */ id_override_new->lib == id->lib);
+      BLI_assert(id_override_old == nullptr || id_override_old->lib == id_root->lib);
+      id_override_new->lib = id_root->lib;
+      /* Remap step below will tag directly linked ones properly as needed. */
+      if (ID_IS_LINKED(id_override_new)) {
+        id_override_new->tag |= LIB_TAG_INDIRECT;
+      }
 
-        if (id_override_old != nullptr) {
-          /* Swap the names between old override ID and new one. */
-          char id_name_buf[MAX_ID_NAME];
-          memcpy(id_name_buf, id_override_old->name, sizeof(id_name_buf));
-          memcpy(id_override_old->name, id_override_new->name, sizeof(id_override_old->name));
-          memcpy(id_override_new->name, id_name_buf, sizeof(id_override_new->name));
-
-          BLI_insertlinkreplace(lb, id_override_old, id_override_new);
-          id_override_old->tag |= LIB_TAG_NO_MAIN;
-          id_override_new->tag &= ~LIB_TAG_NO_MAIN;
-
-          lib_override_object_posemode_transfer(id_override_new, id_override_old);
-
-          if (ID_IS_OVERRIDE_LIBRARY_REAL(id_override_new)) {
-            BLI_assert(ID_IS_OVERRIDE_LIBRARY_REAL(id_override_old));
-
-            id_override_new->override_library->flag = id_override_old->override_library->flag;
-
-            /* Copy over overrides rules from old override ID to new one. */
-            BLI_duplicatelist(&id_override_new->override_library->properties,
-                              &id_override_old->override_library->properties);
-            IDOverrideLibraryProperty *op_new = static_cast(
-                id_override_new->override_library->properties.first);
-            IDOverrideLibraryProperty *op_old = static_cast(
-                id_override_old->override_library->properties.first);
-            for (; op_new; op_new = op_new->next, op_old = op_old->next) {
-              lib_override_library_property_copy(op_new, op_old);
-            }
+      if (id_override_old != nullptr) {
+        /* Swap the names between old override ID and new one. */
+        char id_name_buf[MAX_ID_NAME];
+        memcpy(id_name_buf, id_override_old->name, sizeof(id_name_buf));
+        memcpy(id_override_old->name, id_override_new->name, sizeof(id_override_old->name));
+        memcpy(id_override_new->name, id_name_buf, sizeof(id_override_new->name));
+
+        BLI_insertlinkreplace(lb, id_override_old, id_override_new);
+        id_override_old->tag |= LIB_TAG_NO_MAIN;
+        id_override_new->tag &= ~LIB_TAG_NO_MAIN;
+
+        lib_override_object_posemode_transfer(id_override_new, id_override_old);
+
+        if (ID_IS_OVERRIDE_LIBRARY_REAL(id_override_new)) {
+          BLI_assert(ID_IS_OVERRIDE_LIBRARY_REAL(id_override_old));
+
+          id_override_new->override_library->flag = id_override_old->override_library->flag;
+
+          /* Copy over overrides rules from old override ID to new one. */
+          BLI_duplicatelist(&id_override_new->override_library->properties,
+                            &id_override_old->override_library->properties);
+          IDOverrideLibraryProperty *op_new = static_cast(
+              id_override_new->override_library->properties.first);
+          IDOverrideLibraryProperty *op_old = static_cast(
+              id_override_old->override_library->properties.first);
+          for (; op_new; op_new = op_new->next, op_old = op_old->next) {
+            lib_override_library_property_copy(op_new, op_old);
           }
-
-          BLI_addtail(no_main_ids_list, id_override_old);
-        }
-        else {
-          /* Add to proper main list, ensure unique name for local ID, sort, and clear relevant
-           * tags. */
-          BKE_libblock_management_main_add(bmain, id_override_new);
         }
+
+        BLI_addtail(no_main_ids_list, id_override_old);
+      }
+      else {
+        /* Add to proper main list, ensure unique name for local ID, sort, and clear relevant
+         * tags. */
+        BKE_libblock_management_main_add(bmain, id_override_new);
       }
     }
     FOREACH_MAIN_LISTBASE_ID_END;
@@ -1913,53 +1993,56 @@ static bool lib_override_library_resync(Main *bmain,
    * remapped, and all new local override IDs have gotten their proper original names, otherwise
    * override operations based on those ID names would fail. */
   FOREACH_MAIN_ID_BEGIN (bmain, id) {
-    if (id->tag & LIB_TAG_DOIT && id->newid != nullptr && id->lib == id_root_reference->lib) {
-      ID *id_override_new = id->newid;
-      if (!ID_IS_OVERRIDE_LIBRARY_REAL(id_override_new)) {
-        continue;
-      }
-      ID *id_override_old = static_cast(BLI_ghash_lookup(linkedref_to_old_override, id));
+    if ((id->tag & LIB_TAG_DOIT) == 0 || id->newid == nullptr ||
+        id->lib != id_root_reference->lib) {
+      continue;
+    }
 
-      if (id_override_old == nullptr) {
-        continue;
-      }
-      if (ID_IS_OVERRIDE_LIBRARY_REAL(id_override_old)) {
-        /* Apply rules on new override ID using old one as 'source' data. */
-        /* Note that since we already remapped ID pointers in old override IDs to new ones, we
-         * can also apply ID pointer override rules safely here. */
-        PointerRNA rnaptr_src, rnaptr_dst;
-        RNA_id_pointer_create(id_override_old, &rnaptr_src);
-        RNA_id_pointer_create(id_override_new, &rnaptr_dst);
-
-        /* We remove any operation tagged with `IDOVERRIDE_LIBRARY_FLAG_IDPOINTER_MATCH_REFERENCE`,
-         * that way the potentially new pointer will be properly kept, when old one is still valid
-         * too (typical case: assigning new ID to some usage, while old one remains used elsewhere
-         * in the override hierarchy). */
-        LISTBASE_FOREACH_MUTABLE (
-            IDOverrideLibraryProperty *, op, &id_override_new->override_library->properties) {
-          LISTBASE_FOREACH_MUTABLE (IDOverrideLibraryPropertyOperation *, opop, &op->operations) {
-            if (opop->flag & IDOVERRIDE_LIBRARY_FLAG_IDPOINTER_MATCH_REFERENCE) {
-              lib_override_library_property_operation_clear(opop);
-              BLI_freelinkN(&op->operations, opop);
-            }
-          }
-          if (BLI_listbase_is_empty(&op->operations)) {
-            BKE_lib_override_library_property_delete(id_override_new->override_library, op);
+    ID *id_override_new = id->newid;
+    if (!ID_IS_OVERRIDE_LIBRARY_REAL(id_override_new)) {
+      continue;
+    }
+
+    ID *id_override_old = static_cast(BLI_ghash_lookup(linkedref_to_old_override, id));
+    if (id_override_old == nullptr) {
+      continue;
+    }
+
+    if (ID_IS_OVERRIDE_LIBRARY_REAL(id_override_old)) {
+      /* Apply rules on new override ID using old one as 'source' data. */
+      /* Note that since we already remapped ID pointers in old override IDs to new ones, we
+       * can also apply ID pointer override rules safely here. */
+      PointerRNA rnaptr_src, rnaptr_dst;
+      RNA_id_pointer_create(id_override_old, &rnaptr_src);
+      RNA_id_pointer_create(id_override_new, &rnaptr_dst);
+
+      /* We remove any operation tagged with `IDOVERRIDE_LIBRARY_FLAG_IDPOINTER_MATCH_REFERENCE`,
+       * that way the potentially new pointer will be properly kept, when old one is still valid
+       * too (typical case: assigning new ID to some usage, while old one remains used elsewhere
+       * in the override hierarchy). */
+      LISTBASE_FOREACH_MUTABLE (
+          IDOverrideLibraryProperty *, op, &id_override_new->override_library->properties) {
+        LISTBASE_FOREACH_MUTABLE (IDOverrideLibraryPropertyOperation *, opop, &op->operations) {
+          if (opop->flag & IDOVERRIDE_LIBRARY_FLAG_IDPOINTER_MATCH_REFERENCE) {
+            lib_override_library_property_operation_clear(opop);
+            BLI_freelinkN(&op->operations, opop);
           }
         }
-
-        RNA_struct_override_apply(bmain,
-                                  &rnaptr_dst,
-                                  &rnaptr_src,
-                                  nullptr,
-                                  id_override_new->override_library,
-                                  do_hierarchy_enforce ?
-                                      RNA_OVERRIDE_APPLY_FLAG_IGNORE_ID_POINTERS :
-                                      RNA_OVERRIDE_APPLY_FLAG_NOP);
+        if (BLI_listbase_is_empty(&op->operations)) {
+          BKE_lib_override_library_property_delete(id_override_new->override_library, op);
+        }
       }
 
-      BLI_linklist_prepend(&id_override_old_list, id_override_old);
+      RNA_struct_override_apply(bmain,
+                                &rnaptr_dst,
+                                &rnaptr_src,
+                                nullptr,
+                                id_override_new->override_library,
+                                do_hierarchy_enforce ? RNA_OVERRIDE_APPLY_FLAG_IGNORE_ID_POINTERS :
+                                                       RNA_OVERRIDE_APPLY_FLAG_NOP);
     }
+
+    BLI_linklist_prepend(&id_override_old_list, id_override_old);
   }
   FOREACH_MAIN_ID_END;
 
@@ -2003,9 +2086,13 @@ static bool lib_override_library_resync(Main *bmain,
     }
     /* Also deal with old overrides that went missing in new linked data - only for real local
      * overrides for now, not those who are linked. */
-    else if (id->tag & LIB_TAG_MISSING && !ID_IS_LINKED(id)) {
-      BLI_assert(ID_IS_OVERRIDE_LIBRARY(id));
-      if (!BKE_lib_override_library_is_user_edited(id)) {
+    else if (id->tag & LIB_TAG_MISSING && !ID_IS_LINKED(id) && ID_IS_OVERRIDE_LIBRARY(id)) {
+      if (ID_IS_OVERRIDE_LIBRARY_REAL(id) &&
+          id->override_library->reference->lib->id.tag & LIB_TAG_MISSING) {
+        /* Do not delete overrides which reference is missing because the library itself is missing
+         * (ref. T100586). */
+      }
+      else if (!BKE_lib_override_library_is_user_edited(id)) {
         /* If user never edited them, we can delete them. */
         id->tag |= LIB_TAG_DOIT;
         id->tag &= ~LIB_TAG_MISSING;
@@ -2068,6 +2155,7 @@ static bool lib_override_library_resync(Main *bmain,
                                              id_root_reference,
                                              id_root,
                                              override_resync_residual_storage,
+                                             old_active_object,
                                              true);
   }
 
@@ -2119,12 +2207,12 @@ static bool lib_override_resync_id_lib_level_is_valid(ID *id,
 }
 
 /* Find the root of the override hierarchy the given `id` belongs to. */
-static ID *lib_override_library_main_resync_root_get(Main *bmain, ID *id)
+static ID *lib_override_library_main_resync_root_get(Main * /*bmain*/, ID *id)
 {
   if (!ID_IS_OVERRIDE_LIBRARY_REAL(id)) {
-    const IDTypeInfo *id_type = BKE_idtype_get_info_from_id(id);
-    if (id_type->owner_get != nullptr) {
-      id = id_type->owner_get(bmain, id);
+    ID *id_owner = BKE_id_owner_get(id);
+    if (id_owner != nullptr) {
+      id = id_owner;
     }
     BLI_assert(ID_IS_OVERRIDE_LIBRARY_REAL(id));
   }
@@ -2261,7 +2349,7 @@ static bool lib_override_resync_tagging_finalize_recurse(
     BLI_assert(id_root->override_library != nullptr);
 
     LinkNodePair **id_resync_roots_p;
-    if (!BLI_ghash_ensure_p(id_roots, id_root, (void ***)&id_resync_roots_p)) {
+    if (!BLI_ghash_ensure_p(id_roots, id_root, reinterpret_cast(&id_resync_roots_p))) {
       *id_resync_roots_p = MEM_cnew(__func__);
     }
 
@@ -2311,11 +2399,21 @@ static void lib_override_library_main_resync_on_library_indirect_level(
     if (!ID_IS_OVERRIDE_LIBRARY_REAL(id)) {
       continue;
     }
+
+    if (!lib_override_resync_id_lib_level_is_valid(id, library_indirect_level, true)) {
+      continue;
+    }
+
     if (id->tag & (LIB_TAG_DOIT | LIB_TAG_MISSING)) {
       /* We already processed that ID as part of another ID's hierarchy. */
       continue;
     }
 
+    /* Do not attempt to resync from missing data. */
+    if (((id->tag | id->override_library->reference->tag) & LIB_TAG_MISSING) != 0) {
+      continue;
+    }
+
     if (id->override_library->flag & IDOVERRIDE_LIBRARY_FLAG_NO_HIERARCHY) {
       /* This ID is not part of an override hierarchy. */
       continue;
@@ -2344,6 +2442,11 @@ static void lib_override_library_main_resync_on_library_indirect_level(
       continue;
     }
 
+    /* Do not attempt to resync from missing data. */
+    if (((id->tag | id->override_library->reference->tag) & LIB_TAG_MISSING) != 0) {
+      continue;
+    }
+
     if (id->override_library->flag & IDOVERRIDE_LIBRARY_FLAG_NO_HIERARCHY) {
       /* This ID is not part of an override hierarchy. */
       BLI_assert((id->tag & LIB_TAG_LIB_OVERRIDE_NEED_RESYNC) == 0);
@@ -2436,8 +2539,8 @@ static void lib_override_library_main_resync_on_library_indirect_level(
               2,
               "Resyncing all dependencies under root %s (%p), first one being '%s'...",
               id_root->name,
-              library,
-              ((ID *)id_resync_roots->list->link)->name);
+              reinterpret_cast(library),
+              reinterpret_cast(id_resync_roots->list->link)->name);
     const bool success = lib_override_library_resync(bmain,
                                                      scene,
                                                      view_layer,
@@ -2471,6 +2574,15 @@ static void lib_override_library_main_resync_on_library_indirect_level(
   /* Check there are no left-over IDs needing resync from the current (or higher) level of indirect
    * library level. */
   FOREACH_MAIN_ID_BEGIN (bmain, id) {
+    if (!ID_IS_OVERRIDE_LIBRARY(id)) {
+      continue;
+    }
+    /* Do not attempt to resync to/from missing data. */
+    if (((id->tag | (ID_IS_OVERRIDE_LIBRARY_REAL(id) ? id->override_library->reference->tag : 0)) &
+         LIB_TAG_MISSING) != 0) {
+      continue;
+    }
+
     const bool is_valid_tagged_need_resync = ((id->tag & LIB_TAG_LIB_OVERRIDE_NEED_RESYNC) == 0 ||
                                               lib_override_resync_id_lib_level_is_valid(
                                                   id, library_indirect_level - 1, false));
@@ -2531,7 +2643,7 @@ static int lib_override_sort_libraries_func(LibraryIDLinkCallbackData *cb_data)
 
     if (owner_library_indirect_level >= id->lib->temp_index) {
       id->lib->temp_index = owner_library_indirect_level + 1;
-      *(bool *)cb_data->user_data = true;
+      *reinterpret_cast(cb_data->user_data) = true;
     }
   }
   return IDWALK_RET_NOP;
@@ -2587,6 +2699,9 @@ void BKE_lib_override_library_main_resync(Main *bmain,
     /* Hide the collection from viewport and render. */
     override_resync_residual_storage->flag |= COLLECTION_HIDE_VIEWPORT | COLLECTION_HIDE_RENDER;
   }
+  /* BKE_collection_add above could have tagged the view_layer out of sync. */
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  const Object *old_active_object = BKE_view_layer_active_object_get(view_layer);
 
   /* Necessary to improve performances, and prevent layers matching override sub-collections to be
    * lost when re-syncing the parent override collection.
@@ -2608,8 +2723,15 @@ void BKE_lib_override_library_main_resync(Main *bmain,
   BKE_layer_collection_resync_allow();
 
   /* Essentially ensures that potentially new overrides of new objects will be instantiated. */
-  lib_override_library_create_post_process(
-      bmain, scene, view_layer, nullptr, nullptr, nullptr, override_resync_residual_storage, true);
+  lib_override_library_create_post_process(bmain,
+                                           scene,
+                                           view_layer,
+                                           nullptr,
+                                           nullptr,
+                                           nullptr,
+                                           override_resync_residual_storage,
+                                           old_active_object,
+                                           true);
 
   if (BKE_collection_is_empty(override_resync_residual_storage)) {
     BKE_collection_delete(bmain, override_resync_residual_storage, true);
@@ -2624,6 +2746,8 @@ void BKE_lib_override_library_main_resync(Main *bmain,
                 library->filepath);
     }
   }
+
+  BLI_assert(BKE_main_namemap_validate(bmain));
 }
 
 void BKE_lib_override_library_delete(Main *bmain, ID *id_root)
@@ -2687,7 +2811,7 @@ void BKE_lib_override_library_make_local(ID *id)
   }
 
   if (GS(id->name) == ID_SCE) {
-    Collection *master_collection = ((Scene *)id)->master_collection;
+    Collection *master_collection = reinterpret_cast(id)->master_collection;
     if (master_collection != nullptr) {
       master_collection->id.flag &= ~LIB_EMBEDDED_DATA_LIB_OVERRIDE;
     }
@@ -3069,9 +3193,9 @@ bool BKE_lib_override_library_status_check_local(Main *bmain, ID *local)
     /* Our beloved pose's bone cross-data pointers. Usually, depsgraph evaluation would
      * ensure this is valid, but in some situations (like hidden collections etc.) this won't
      * be the case, so we need to take care of this ourselves. */
-    Object *ob_local = (Object *)local;
+    Object *ob_local = reinterpret_cast(local);
     if (ob_local->type == OB_ARMATURE) {
-      Object *ob_reference = (Object *)local->override_library->reference;
+      Object *ob_reference = reinterpret_cast(local->override_library->reference);
       BLI_assert(ob_local->data != nullptr);
       BLI_assert(ob_reference->data != nullptr);
       BKE_pose_ensure(bmain, ob_local, static_cast(ob_local->data), true);
@@ -3129,9 +3253,9 @@ bool BKE_lib_override_library_status_check_reference(Main *bmain, ID *local)
     /* Our beloved pose's bone cross-data pointers. Usually, depsgraph evaluation would
      * ensure this is valid, but in some situations (like hidden collections etc.) this won't
      * be the case, so we need to take care of this ourselves. */
-    Object *ob_local = (Object *)local;
+    Object *ob_local = reinterpret_cast(local);
     if (ob_local->type == OB_ARMATURE) {
-      Object *ob_reference = (Object *)local->override_library->reference;
+      Object *ob_reference = reinterpret_cast(local->override_library->reference);
       BLI_assert(ob_local->data != nullptr);
       BLI_assert(ob_reference->data != nullptr);
       BKE_pose_ensure(bmain, ob_local, static_cast(ob_local->data), true);
@@ -3177,9 +3301,9 @@ bool BKE_lib_override_library_operations_create(Main *bmain, ID *local)
       /* Our beloved pose's bone cross-data pointers. Usually, depsgraph evaluation would
        * ensure this is valid, but in some situations (like hidden collections etc.) this won't
        * be the case, so we need to take care of this ourselves. */
-      Object *ob_local = (Object *)local;
+      Object *ob_local = reinterpret_cast(local);
       if (ob_local->type == OB_ARMATURE) {
-        Object *ob_reference = (Object *)local->override_library->reference;
+        Object *ob_reference = reinterpret_cast(local->override_library->reference);
         BLI_assert(ob_local->data != nullptr);
         BLI_assert(ob_reference->data != nullptr);
         BKE_pose_ensure(bmain, ob_local, static_cast(ob_local->data), true);
@@ -3233,7 +3357,7 @@ static void lib_override_library_operations_create_cb(TaskPool *__restrict pool,
   if (BKE_lib_override_library_operations_create(create_data->bmain, id)) {
     /* Technically no need for atomic, all jobs write the same value and we only care if one did
      * it. But play safe and avoid implicit assumptions. */
-    atomic_fetch_and_or_uint8((uint8_t *)&create_data->changed, true);
+    atomic_fetch_and_or_uint8(reinterpret_cast(&create_data->changed), true);
   }
 }
 
@@ -3273,7 +3397,7 @@ bool BKE_lib_override_library_main_operations_create(Main *bmain, const bool for
       /* Usual issue with pose, it's quiet rare but sometimes they may not be up to date when this
        * function is called. */
       if (GS(id->name) == ID_OB) {
-        Object *ob = (Object *)id;
+        Object *ob = reinterpret_cast(id);
         if (ob->type == OB_ARMATURE) {
           BLI_assert(ob->data != nullptr);
           BKE_pose_ensure(bmain, ob, static_cast(ob->data), true);
@@ -3592,6 +3716,9 @@ void BKE_lib_override_library_update(Main *bmain, ID *local)
     return;
   }
 
+  /* Remove the pair (idname, lib) of this temp id from the name map. */
+  BKE_main_namemap_remove_name(bmain, tmp_id, tmp_id->name + 2);
+
   tmp_id->lib = local->lib;
 
   /* This ID name is problematic, since it is an 'rna name property' it should not be editable or
@@ -3606,7 +3733,9 @@ void BKE_lib_override_library_update(Main *bmain, ID *local)
   Key *tmp_key = BKE_key_from_id(tmp_id);
   if (local_key != nullptr && tmp_key != nullptr) {
     tmp_key->id.flag |= (local_key->id.flag & LIB_EMBEDDED_DATA_LIB_OVERRIDE);
+    BKE_main_namemap_remove_name(bmain, &tmp_key->id, tmp_key->id.name + 2);
     tmp_key->id.lib = local_key->id.lib;
+    BLI_strncpy(tmp_key->id.name, local_key->id.name, sizeof(tmp_key->id.name));
   }
 
   PointerRNA rnaptr_src, rnaptr_dst, rnaptr_storage_stack, *rnaptr_storage = nullptr;
@@ -3643,8 +3772,10 @@ void BKE_lib_override_library_update(Main *bmain, ID *local)
   }
 
   /* Again, horribly inefficient in our case, we need something off-Main
-   * (aka more generic nolib copy/free stuff)! */
-  BKE_id_free_ex(bmain, tmp_id, LIB_ID_FREE_NO_UI_USER, true);
+   * (aka more generic nolib copy/free stuff).
+   * NOTE: Do not remove this tmp_id's name from the namemap here, since this name actually still
+   * exists in `bmain`. */
+  BKE_id_free_ex(bmain, tmp_id, LIB_ID_FREE_NO_UI_USER | LIB_ID_FREE_NO_NAMEMAP_REMOVE, true);
 
   if (GS(local->name) == ID_AR) {
     /* Fun times again, thanks to bone pointers in pose data of objects. We keep same ID addresses,
@@ -3688,6 +3819,8 @@ void BKE_lib_override_library_main_update(Main *bmain)
   Main *orig_gmain = G_MAIN;
   G_MAIN = bmain;
 
+  BLI_assert(BKE_main_namemap_validate(bmain));
+
   FOREACH_MAIN_ID_BEGIN (bmain, id) {
     if (id->override_library != nullptr) {
       BKE_lib_override_library_update(bmain, id);
@@ -3695,6 +3828,8 @@ void BKE_lib_override_library_main_update(Main *bmain)
   }
   FOREACH_MAIN_ID_END;
 
+  BLI_assert(BKE_main_namemap_validate(bmain));
+
   G_MAIN = orig_gmain;
 }
 
@@ -3706,7 +3841,7 @@ bool BKE_lib_override_library_id_is_user_deletable(Main *bmain, ID *id)
   if (GS(id->name) != ID_OB) {
     return true;
   }
-  Object *ob = (Object *)id;
+  Object *ob = reinterpret_cast(id);
   LISTBASE_FOREACH (Collection *, collection, &bmain->collections) {
     if (!ID_IS_OVERRIDE_LIBRARY(collection)) {
       continue;
@@ -3777,7 +3912,7 @@ ID *BKE_lib_override_library_operations_store_start(Main *bmain,
    * (and possibly all over Blender code).
    * Not impossible to do, but would rather see first is extra useless usual user handling is
    * actually a (performances) issue here, before doing it. */
-  storage_id = BKE_id_copy((Main *)override_storage, local);
+  storage_id = BKE_id_copy(reinterpret_cast
(override_storage), local);
 
   if (storage_id != nullptr) {
     PointerRNA rnaptr_reference, rnaptr_final, rnaptr_storage;
@@ -3816,7 +3951,7 @@ void BKE_lib_override_library_operations_store_end(
 void BKE_lib_override_library_operations_store_finalize(OverrideLibraryStorage *override_storage)
 {
   /* We cannot just call BKE_main_free(override_storage), not until we have option to make
-   * 'ghost' copies of IDs without increasing usercount of used data-blocks. */
+   * 'ghost' copies of IDs without increasing user-count of used data-blocks. */
   ID *id;
 
   FOREACH_MAIN_ID_BEGIN (override_storage, id) {
diff --git a/source/blender/blenkernel/intern/lib_principle_properties.c b/source/blender/blenkernel/intern/lib_principle_properties.c
deleted file mode 100644
index 204ca9ff9d6..00000000000
--- a/source/blender/blenkernel/intern/lib_principle_properties.c
+++ /dev/null
@@ -1,106 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later
- * Copyright 2022 Blender Foundation. All rights reserved. */
-
-/** \file
- * \ingroup bke
- */
-
-#include 
-#include 
-#include 
-
-#include "CLG_log.h"
-
-#include "MEM_guardedalloc.h"
-
-#include "DNA_ID.h"
-
-#include "BKE_lib_id.h"
-#include "BKE_lib_principle_properties.h"
-#include "BKE_report.h"
-
-#include "BLO_readfile.h"
-
-#include "BLI_listbase.h"
-#include "BLI_string.h"
-
-#include "RNA_access.h"
-#include "RNA_prototypes.h"
-#include "RNA_types.h"
-
-static CLG_LogRef LOG = {"bke.idprincipleprops"};
-
-IDPrincipleProperties *BKE_lib_principleprop_init(ID *id)
-{
-  BLI_assert(id->principle_properties == NULL);
-
-  /* Else, generate new empty override. */
-  id->principle_properties = MEM_callocN(sizeof(*id->principle_properties), __func__);
-
-  return id->principle_properties;
-}
-
-void BKE_lib_principleprop_clear(IDPrincipleProperties *principle_props, bool UNUSED(do_id_user))
-{
-  LISTBASE_FOREACH_MUTABLE (IDPrincipleProperty *, pprop, &principle_props->properties) {
-    BLI_assert(pprop->rna_path != NULL);
-    MEM_freeN(pprop->rna_path);
-    MEM_freeN(pprop);
-  }
-  BLI_listbase_clear(&principle_props->properties);
-  principle_props->flag = 0;
-}
-
-void BKE_lib_principleprop_free(IDPrincipleProperties **principle_props, bool do_id_user)
-{
-  BLI_assert(*principle_props != NULL);
-
-  BKE_lib_principleprop_clear(*principle_props, do_id_user);
-  MEM_freeN(*principle_props);
-  *principle_props = NULL;
-}
-
-IDPrincipleProperty *BKE_lib_principleprop_find(IDPrincipleProperties *principle_props,
-                                                const char *rna_path)
-{
-  return BLI_findstring_ptr(
-      &principle_props->properties, rna_path, offsetof(IDPrincipleProperty, rna_path));
-}
-
-IDPrincipleProperty *BKE_lib_principleprop_get(IDPrincipleProperties *principle_props,
-                                               const char *rna_path,
-                                               bool *r_created)
-{
-  IDPrincipleProperty *pprop = BKE_lib_principleprop_find(principle_props, rna_path);
-
-  if (pprop == NULL) {
-    pprop = MEM_callocN(sizeof(*pprop), __func__);
-    pprop->rna_path = BLI_strdup(rna_path);
-    BLI_addtail(&principle_props->properties, pprop);
-
-    if (r_created) {
-      *r_created = true;
-    }
-  }
-  else if (r_created) {
-    *r_created = false;
-  }
-
-  return pprop;
-}
-
-void BKE_lib_principleprop_delete(IDPrincipleProperties *principle_props,
-                                  IDPrincipleProperty *principle_prop)
-{
-  BLI_remlink(&principle_props->properties, principle_prop);
-}
-
-bool BKE_lib_principleprop_rna_property_find(struct PointerRNA *idpoin,
-                                             const struct IDPrincipleProperty *principle_prop,
-                                             struct PointerRNA *r_principle_poin,
-                                             struct PropertyRNA **r_principle_prop)
-{
-  BLI_assert(RNA_struct_is_ID(idpoin->type));
-  return RNA_path_resolve_property(
-      idpoin, principle_prop->rna_path, r_principle_poin, r_principle_prop);
-}
diff --git a/source/blender/blenkernel/intern/lib_query.c b/source/blender/blenkernel/intern/lib_query.c
index 38252a46b93..50843b18d18 100644
--- a/source/blender/blenkernel/intern/lib_query.c
+++ b/source/blender/blenkernel/intern/lib_query.c
@@ -391,8 +391,7 @@ uint64_t BKE_library_id_can_use_filter_id(const ID *id_owner)
 
   switch ((ID_Type)id_type_owner) {
     case ID_LI:
-      /* ID_LI doesn't exist as filter_id. */
-      return 0;
+      return FILTER_ID_LI;
     case ID_SCE:
       return FILTER_ID_OB | FILTER_ID_WO | FILTER_ID_SCE | FILTER_ID_MC | FILTER_ID_MA |
              FILTER_ID_GR | FILTER_ID_TXT | FILTER_ID_LS | FILTER_ID_MSK | FILTER_ID_SO |
@@ -472,6 +471,8 @@ uint64_t BKE_library_id_can_use_filter_id(const ID *id_owner)
       /* Deprecated... */
       return 0;
   }
+
+  BLI_assert_unreachable();
   return 0;
 }
 
@@ -695,8 +696,8 @@ static void lib_query_unused_ids_tag_recurse(Main *bmain,
   bool has_valid_from_users = false;
   /* Preemptively consider this ID as unused. That way if there is a loop of dependency leading
    * back to it, it won't create a fake 'valid user' detection.
-   * NOTE: This can only only be done for a subset of IDs, some types are never 'indirectly
-   * unused', same for IDs with a fake user. */
+   * NOTE: This can only be done for a subset of IDs, some types are never 'indirectly unused',
+   * same for IDs with a fake user. */
   if ((id->flag & LIB_FAKEUSER) == 0 && !ELEM(GS(id->name), ID_SCE, ID_WM, ID_SCR, ID_WS, ID_LI)) {
     id->tag |= tag;
   }
@@ -710,9 +711,8 @@ static void lib_query_unused_ids_tag_recurse(Main *bmain,
     ID *id_from = id_from_item->id_pointer.from;
     if ((id_from->flag & LIB_EMBEDDED_DATA) != 0) {
       /* Directly 'by-pass' to actual real ID owner. */
-      const IDTypeInfo *type_info_from = BKE_idtype_get_info_from_id(id_from);
-      BLI_assert(type_info_from->owner_get != NULL);
-      id_from = type_info_from->owner_get(bmain, id_from);
+      id_from = BKE_id_owner_get(id_from);
+      BLI_assert(id_from != NULL);
     }
 
     lib_query_unused_ids_tag_recurse(
diff --git a/source/blender/blenkernel/intern/lib_remap.c b/source/blender/blenkernel/intern/lib_remap.c
index 246999a1179..2ebdc6788d9 100644
--- a/source/blender/blenkernel/intern/lib_remap.c
+++ b/source/blender/blenkernel/intern/lib_remap.c
@@ -428,10 +428,13 @@ static void libblock_remap_data_update_tags(ID *old_id, ID *new_id, void *user_d
 }
 
 static void libblock_remap_reset_remapping_status_callback(ID *old_id,
-                                                           ID *UNUSED(new_id),
+                                                           ID *new_id,
                                                            void *UNUSED(user_data))
 {
   BKE_libblock_runtime_reset_remapping_status(old_id);
+  if (new_id != NULL) {
+    BKE_libblock_runtime_reset_remapping_status(new_id);
+  }
 }
 
 /**
@@ -814,7 +817,7 @@ void BKE_libblock_relink_ex(
     Main *bmain, void *idv, void *old_idv, void *new_idv, const short remap_flags)
 {
 
-  /* Should be able to replace all _relink() funcs (constraints, rigidbody, etc.) ? */
+  /* Should be able to replace all _relink() functions (constraints, rigidbody, etc.) ? */
 
   ID *id = idv;
   ID *old_id = old_idv;
diff --git a/source/blender/blenkernel/intern/library.c b/source/blender/blenkernel/intern/library.c
index 03a17b2ecc5..516fb9b75b6 100644
--- a/source/blender/blenkernel/intern/library.c
+++ b/source/blender/blenkernel/intern/library.c
@@ -26,14 +26,26 @@
 #include "BKE_lib_query.h"
 #include "BKE_library.h"
 #include "BKE_main.h"
+#include "BKE_main_namemap.h"
 #include "BKE_packedFile.h"
 
 /* Unused currently. */
 // static CLG_LogRef LOG = {.identifier = "bke.library"};
 
+struct BlendWriter;
+struct BlendDataReader;
+
+static void library_runtime_reset(Library *lib)
+{
+  if (lib->runtime.name_map) {
+    BKE_main_namemap_destroy(&lib->runtime.name_map);
+  }
+}
+
 static void library_free_data(ID *id)
 {
   Library *library = (Library *)id;
+  library_runtime_reset(library);
   if (library->packedfile) {
     BKE_packedfile_free(library->packedfile);
   }
@@ -61,9 +73,15 @@ static void library_foreach_path(ID *id, BPathForeachPathData *bpath_data)
   }
 }
 
+static void library_blend_read_data(struct BlendDataReader *UNUSED(reader), ID *id)
+{
+  Library *lib = (Library *)id;
+  lib->runtime.name_map = NULL;
+}
+
 IDTypeInfo IDType_ID_LI = {
     .id_code = ID_LI,
-    .id_filter = 0,
+    .id_filter = FILTER_ID_LI,
     .main_listbase_index = INDEX_ID_LI,
     .struct_size = sizeof(Library),
     .name = "Library",
@@ -79,10 +97,10 @@ IDTypeInfo IDType_ID_LI = {
     .foreach_id = library_foreach_id,
     .foreach_cache = NULL,
     .foreach_path = library_foreach_path,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = NULL,
-    .blend_read_data = NULL,
+    .blend_read_data = library_blend_read_data,
     .blend_read_lib = NULL,
     .blend_read_expand = NULL,
 
@@ -104,7 +122,7 @@ void BKE_library_filepath_set(Main *bmain, Library *lib, const char *filepath)
   /* Not essential but set `filepath_abs` is an absolute copy of value which
    * is more useful if its kept in sync. */
   if (BLI_path_is_rel(lib->filepath_abs)) {
-    /* NOTE(campbell): the file may be unsaved, in this case, setting the
+    /* NOTE(@campbellbarton): the file may be unsaved, in this case, setting the
      * `filepath_abs` on an indirectly linked path is not allowed from the
      * outliner, and its not really supported but allow from here for now
      * since making local could cause this to be directly linked.
diff --git a/source/blender/blenkernel/intern/light.c b/source/blender/blenkernel/intern/light.c
index 879e4e24928..42af11294c9 100644
--- a/source/blender/blenkernel/intern/light.c
+++ b/source/blender/blenkernel/intern/light.c
@@ -80,6 +80,7 @@ static void light_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const int
       BKE_id_copy_ex(
           bmain, (ID *)la_src->nodetree, (ID **)&la_dst->nodetree, flag_private_id_data);
     }
+    la_dst->nodetree->owner_id = &la_dst->id;
   }
 
   if ((flag & LIB_ID_COPY_NO_PREVIEW) == 0) {
@@ -188,7 +189,7 @@ IDTypeInfo IDType_ID_LA = {
     .foreach_id = light_foreach_id,
     .foreach_cache = NULL,
     .foreach_path = NULL,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = light_blend_write,
     .blend_read_data = light_blend_read_data,
diff --git a/source/blender/blenkernel/intern/lightprobe.c b/source/blender/blenkernel/intern/lightprobe.c
index 9e731b1f878..a2151d6c6f1 100644
--- a/source/blender/blenkernel/intern/lightprobe.c
+++ b/source/blender/blenkernel/intern/lightprobe.c
@@ -85,7 +85,7 @@ IDTypeInfo IDType_ID_LP = {
     .foreach_id = lightprobe_foreach_id,
     .foreach_cache = NULL,
     .foreach_path = NULL,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = lightprobe_blend_write,
     .blend_read_data = lightprobe_blend_read_data,
diff --git a/source/blender/blenkernel/intern/linestyle.c b/source/blender/blenkernel/intern/linestyle.c
index 12a661d139b..cba1bc414c1 100644
--- a/source/blender/blenkernel/intern/linestyle.c
+++ b/source/blender/blenkernel/intern/linestyle.c
@@ -72,6 +72,7 @@ static void linestyle_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const
                    (ID *)linestyle_src->nodetree,
                    (ID **)&linestyle_dst->nodetree,
                    flag_private_id_data);
+    linestyle_dst->nodetree->owner_id = &linestyle_dst->id;
   }
 
   LineStyleModifier *linestyle_modifier;
@@ -748,7 +749,7 @@ IDTypeInfo IDType_ID_LS = {
     .foreach_id = linestyle_foreach_id,
     .foreach_cache = NULL,
     .foreach_path = NULL,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = linestyle_blend_write,
     .blend_read_data = linestyle_blend_read_data,
@@ -2041,9 +2042,7 @@ void BKE_linestyle_default_shader(const bContext *C, FreestyleLineStyle *linesty
 
   BLI_assert(linestyle->nodetree == NULL);
 
-  ntree = ntreeAddTree(NULL, "stroke_shader", "ShaderNodeTree");
-
-  linestyle->nodetree = ntree;
+  ntree = ntreeAddTreeEmbedded(NULL, &linestyle->id, "stroke_shader", "ShaderNodeTree");
 
   uv_along_stroke = nodeAddStaticNode(C, ntree, SH_NODE_UVALONGSTROKE);
   uv_along_stroke->locx = 0.0f;
diff --git a/source/blender/blenkernel/intern/main.c b/source/blender/blenkernel/intern/main.c
index b9ed783fa8c..239aacf28d6 100644
--- a/source/blender/blenkernel/intern/main.c
+++ b/source/blender/blenkernel/intern/main.c
@@ -24,6 +24,7 @@
 #include "BKE_lib_query.h"
 #include "BKE_main.h"
 #include "BKE_main_idmap.h"
+#include "BKE_main_namemap.h"
 
 #include "IMB_imbuf.h"
 #include "IMB_imbuf_types.h"
@@ -184,6 +185,10 @@ void BKE_main_free(Main *mainvar)
     BKE_main_idmap_destroy(mainvar->id_map);
   }
 
+  if (mainvar->name_map) {
+    BKE_main_namemap_destroy(&mainvar->name_map);
+  }
+
   BLI_spin_end((SpinLock *)mainvar->lock);
   MEM_freeN(mainvar->lock);
   MEM_freeN(mainvar);
diff --git a/source/blender/blenkernel/intern/main_namemap.cc b/source/blender/blenkernel/intern/main_namemap.cc
new file mode 100644
index 00000000000..a600afb4ed1
--- /dev/null
+++ b/source/blender/blenkernel/intern/main_namemap.cc
@@ -0,0 +1,500 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/** \file
+ * \ingroup bke
+ */
+
+#include "BKE_idtype.h"
+#include "BKE_lib_id.h"
+#include "BKE_main.h"
+#include "BKE_main_namemap.h"
+
+#include "BLI_assert.h"
+#include "BLI_bitmap.h"
+#include "BLI_ghash.h"
+#include "BLI_listbase.h"
+#include "BLI_map.hh"
+#include "BLI_math_base.hh"
+#include "BLI_set.hh"
+#include "BLI_string_utf8.h"
+#include "BLI_string_utils.h"
+
+#include "DNA_ID.h"
+
+#include "MEM_guardedalloc.h"
+
+#include "CLG_log.h"
+
+static CLG_LogRef LOG = {"bke.main_namemap"};
+
+//#define DEBUG_PRINT_MEMORY_USAGE
+
+using namespace blender;
+
+/* Assumes and ensure that the suffix number can never go beyond 1 billion. */
+#define MAX_NUMBER 1000000000
+/* We do not want to get "name.000", so minimal number is 1. */
+#define MIN_NUMBER 1
+
+/**
+ * Helper building final ID name from given base_name and number.
+ *
+ * If everything goes well and we do generate a valid final ID name in given name, we return
+ * true. In case the final name would overflow the allowed ID name length, or given number is
+ * bigger than maximum allowed value, we truncate further the base_name (and given name, which is
+ * assumed to have the same 'base_name' part), and return false.
+ */
+static bool id_name_final_build(char *name, char *base_name, size_t base_name_len, int number)
+{
+  char number_str[11]; /* Dot + nine digits + NULL terminator. */
+  size_t number_str_len = BLI_snprintf_rlen(number_str, ARRAY_SIZE(number_str), ".%.3d", number);
+
+  /* If the number would lead to an overflow of the maximum ID name length, we need to truncate
+   * the base name part and do all the number checks again. */
+  if (base_name_len + number_str_len >= MAX_NAME || number >= MAX_NUMBER) {
+    if (base_name_len + number_str_len >= MAX_NAME) {
+      base_name_len = MAX_NAME - number_str_len - 1;
+    }
+    else {
+      base_name_len--;
+    }
+    base_name[base_name_len] = '\0';
+
+    /* Code above may have generated invalid utf-8 string, due to raw truncation.
+     * Ensure we get a valid one now. */
+    base_name_len -= (size_t)BLI_str_utf8_invalid_strip(base_name, base_name_len);
+
+    /* Also truncate orig name, and start the whole check again. */
+    name[base_name_len] = '\0';
+    return false;
+  }
+
+  /* We have our final number, we can put it in name and exit the function. */
+  BLI_strncpy(name + base_name_len, number_str, number_str_len + 1);
+  return true;
+}
+
+/* Key used in set/map lookups: just a string name. */
+struct UniqueName_Key {
+  char name[MAX_NAME];
+  uint64_t hash() const
+  {
+    return BLI_ghashutil_strhash_n(name, MAX_NAME);
+  }
+  bool operator==(const UniqueName_Key &o) const
+  {
+    return !BLI_ghashutil_strcmp(name, o.name);
+  }
+};
+
+/* Tracking of used numeric suffixes. For each base name:
+ *
+ * - Exactly track which of the lowest 1024 suffixes are in use,
+ *   whenever there is a name collision we pick the lowest "unused"
+ *   one. This is done with a bit map.
+ * - Above 1024, do not track them exactly, just track the maximum
+ *   suffix value seen so far. Upon collision, assign number that is
+ *   one larger.
+ */
+struct UniqueName_Value {
+  static constexpr unsigned max_exact_tracking = 1024;
+  BLI_BITMAP_DECLARE(mask, max_exact_tracking);
+  int max_value = 0;
+
+  void mark_used(int number)
+  {
+    if (number >= 0 && number < max_exact_tracking) {
+      BLI_BITMAP_ENABLE(mask, number);
+    }
+    if (number < MAX_NUMBER) {
+      math::max_inplace(max_value, number);
+    }
+  }
+
+  void mark_unused(int number)
+  {
+    if (number >= 0 && number < max_exact_tracking) {
+      BLI_BITMAP_DISABLE(mask, number);
+    }
+    if (number > 0 && number == max_value) {
+      --max_value;
+    }
+  }
+
+  bool use_if_unused(int number)
+  {
+    if (number >= 0 && number < max_exact_tracking) {
+      if (!BLI_BITMAP_TEST_BOOL(mask, number)) {
+        BLI_BITMAP_ENABLE(mask, number);
+        math::max_inplace(max_value, number);
+        return true;
+      }
+    }
+    return false;
+  }
+
+  int use_smallest_unused()
+  {
+    /* Find the smallest available one <1k.
+     * However we never want to pick zero ("none") suffix, even if it is
+     * available, e.g. if Foo.001 was used and we want to create another
+     * Foo.001, we should return Foo.002 and not Foo.
+     * So while searching, mark #0 as "used" to make sure we don't find it,
+     * and restore the value afterwards. */
+
+    BLI_bitmap prev_first = mask[0];
+    mask[0] |= 1;
+    int result = BLI_bitmap_find_first_unset(mask, max_exact_tracking);
+    if (result >= 0) {
+      BLI_BITMAP_ENABLE(mask, result);
+      math::max_inplace(max_value, result);
+    }
+    mask[0] |= prev_first & 1; /* Restore previous value of #0 bit. */
+    return result;
+  }
+};
+
+/* Tracking of names for a single ID type. */
+struct UniqueName_TypeMap {
+  /* Set of full names that are in use. */
+  Set full_names;
+  /* For each base name (i.e. without numeric suffix), track the
+   * numeric suffixes that are in use. */
+  Map base_name_to_num_suffix;
+};
+
+struct UniqueName_Map {
+  UniqueName_TypeMap type_maps[INDEX_ID_MAX];
+
+  UniqueName_TypeMap *find_by_type(short id_type)
+  {
+    int index = BKE_idtype_idcode_to_index(id_type);
+    return index >= 0 ? &type_maps[index] : nullptr;
+  }
+};
+
+struct UniqueName_Map *BKE_main_namemap_create()
+{
+  struct UniqueName_Map *map = MEM_new(__func__);
+  return map;
+}
+
+void BKE_main_namemap_destroy(struct UniqueName_Map **r_name_map)
+{
+#ifdef DEBUG_PRINT_MEMORY_USAGE
+  int64_t size_sets = 0;
+  int64_t size_maps = 0;
+  for (const UniqueName_TypeMap &type_map : (*r_name_map)->type_maps) {
+    size_sets += type_map.full_names.size_in_bytes();
+    size_maps += type_map.base_name_to_num_suffix.size_in_bytes();
+  }
+  printf(
+      "NameMap memory usage: sets %.1fKB, maps %.1fKB\n", size_sets / 1024.0, size_maps / 1024.0);
+#endif
+  MEM_delete(*r_name_map);
+  *r_name_map = nullptr;
+}
+
+static void main_namemap_populate(UniqueName_Map *name_map, struct Main *bmain, ID *ignore_id)
+{
+  BLI_assert_msg(name_map != nullptr, "name_map should not be null");
+  for (UniqueName_TypeMap &type_map : name_map->type_maps) {
+    type_map.base_name_to_num_suffix.clear();
+  }
+  Library *library = ignore_id->lib;
+  ID *id;
+  FOREACH_MAIN_ID_BEGIN (bmain, id) {
+    if ((id == ignore_id) || (id->lib != library)) {
+      continue;
+    }
+    UniqueName_TypeMap *type_map = name_map->find_by_type(GS(id->name));
+    BLI_assert(type_map != nullptr);
+
+    /* Insert the full name into the set. */
+    UniqueName_Key key;
+    BLI_strncpy(key.name, id->name + 2, MAX_NAME);
+    type_map->full_names.add(key);
+
+    /* Get the name and number parts ("name.number"). */
+    int number = MIN_NUMBER;
+    BLI_split_name_num(key.name, &number, id->name + 2, '.');
+
+    /* Get and update the entry for this base name. */
+    UniqueName_Value &val = type_map->base_name_to_num_suffix.lookup_or_add_default(key);
+    val.mark_used(number);
+  }
+  FOREACH_MAIN_ID_END;
+}
+
+/* Get the name map object used for the given Main/ID.
+ * Lazily creates and populates the contents of the name map, if ensure_created is true.
+ * NOTE: if the contents are populated, the name of the given ID itself is not added. */
+static UniqueName_Map *get_namemap_for(Main *bmain, ID *id, bool ensure_created)
+{
+  if (id->lib != nullptr) {
+    if (ensure_created && id->lib->runtime.name_map == nullptr) {
+      id->lib->runtime.name_map = BKE_main_namemap_create();
+      main_namemap_populate(id->lib->runtime.name_map, bmain, id);
+    }
+    return id->lib->runtime.name_map;
+  }
+  if (ensure_created && bmain->name_map == nullptr) {
+    bmain->name_map = BKE_main_namemap_create();
+    main_namemap_populate(bmain->name_map, bmain, id);
+  }
+  return bmain->name_map;
+}
+
+bool BKE_main_namemap_get_name(struct Main *bmain, struct ID *id, char *name)
+{
+#ifndef __GNUC__ /* GCC warns with `nonull-compare`. */
+  BLI_assert(bmain != nullptr);
+  BLI_assert(id != nullptr);
+#endif
+  UniqueName_Map *name_map = get_namemap_for(bmain, id, true);
+  BLI_assert(name_map != nullptr);
+  BLI_assert(strlen(name) < MAX_NAME);
+  UniqueName_TypeMap *type_map = name_map->find_by_type(GS(id->name));
+  BLI_assert(type_map != nullptr);
+
+  bool is_name_changed = false;
+
+  UniqueName_Key key;
+  while (true) {
+    /* Check if the full original name has a duplicate. */
+    BLI_strncpy(key.name, name, MAX_NAME);
+    const bool has_dup = type_map->full_names.contains(key);
+
+    /* Get the name and number parts ("name.number"). */
+    int number = MIN_NUMBER;
+    size_t base_name_len = BLI_split_name_num(key.name, &number, name, '.');
+
+    bool added_new = false;
+    UniqueName_Value &val = type_map->base_name_to_num_suffix.lookup_or_add_cb(key, [&]() {
+      added_new = true;
+      return UniqueName_Value();
+    });
+    if (added_new || !has_dup) {
+      /* This base name is not used at all yet, or the full original
+       * name has no duplicates. The latter could happen if splitting
+       * by number would produce the same values, for different name
+       * strings (e.g. Foo.001 and Foo.1). */
+      val.mark_used(number);
+
+      if (!has_dup) {
+        BLI_strncpy(key.name, name, MAX_NAME);
+        type_map->full_names.add(key);
+      }
+      return is_name_changed;
+    }
+
+    /* The base name is already used. But our number suffix might not be used yet. */
+    int number_to_use = -1;
+    if (val.use_if_unused(number)) {
+      /* Our particular number suffix is not used yet: use it. */
+      number_to_use = number;
+    }
+    else {
+      /* Find lowest free under 1k and use it. */
+      number_to_use = val.use_smallest_unused();
+
+      /* Did not find one under 1k. */
+      if (number_to_use == -1) {
+        if (number >= MIN_NUMBER && number > val.max_value) {
+          val.max_value = number;
+          number_to_use = number;
+        }
+        else {
+          val.max_value++;
+          number_to_use = val.max_value;
+        }
+      }
+    }
+
+    /* Try to build final name from the current base name and the number.
+     * Note that this can fail due to too long base name, or a too large number,
+     * in which case it will shorten the base name, and we'll start again. */
+    BLI_assert(number_to_use >= MIN_NUMBER);
+    if (id_name_final_build(name, key.name, base_name_len, number_to_use)) {
+      /* All good, add final name to the set. */
+      BLI_strncpy(key.name, name, MAX_NAME);
+      type_map->full_names.add(key);
+      break;
+    }
+
+    /* Name had to be truncated, or number too large: mark
+     * the output name as definitely changed, and proceed with the
+     * truncated name again. */
+    is_name_changed = true;
+  }
+  return is_name_changed;
+}
+
+void BKE_main_namemap_remove_name(struct Main *bmain, struct ID *id, const char *name)
+{
+#ifndef __GNUC__ /* GCC warns with `nonull-compare`. */
+  BLI_assert(bmain != nullptr);
+  BLI_assert(id != nullptr);
+  BLI_assert(name != nullptr);
+#endif
+  /* Name is empty or not initialized yet, nothing to remove. */
+  if (name[0] == '\0') {
+    return;
+  }
+
+  struct UniqueName_Map *name_map = get_namemap_for(bmain, id, false);
+  if (name_map == nullptr) {
+    return;
+  }
+  BLI_assert(strlen(name) < MAX_NAME);
+  UniqueName_TypeMap *type_map = name_map->find_by_type(GS(id->name));
+  BLI_assert(type_map != nullptr);
+
+  UniqueName_Key key;
+  /* Remove full name from the set. */
+  BLI_strncpy(key.name, name, MAX_NAME);
+  type_map->full_names.remove(key);
+
+  int number = MIN_NUMBER;
+  BLI_split_name_num(key.name, &number, name, '.');
+  UniqueName_Value *val = type_map->base_name_to_num_suffix.lookup_ptr(key);
+  if (val == nullptr) {
+    return;
+  }
+  if (number == 0 && val->max_value == 0) {
+    /* This was the only base name usage, remove whole key. */
+    type_map->base_name_to_num_suffix.remove(key);
+    return;
+  }
+  val->mark_unused(number);
+}
+
+struct Uniqueness_Key {
+  char name[MAX_ID_NAME];
+  Library *lib;
+  uint64_t hash() const
+  {
+    return BLI_ghashutil_combine_hash(BLI_ghashutil_strhash_n(name, MAX_ID_NAME),
+                                      BLI_ghashutil_ptrhash(lib));
+  }
+  bool operator==(const Uniqueness_Key &o) const
+  {
+    return lib == o.lib && !BLI_ghashutil_strcmp(name, o.name);
+  }
+};
+
+static bool main_namemap_validate_and_fix(Main *bmain, const bool do_fix)
+{
+  Set id_names_libs;
+  bool is_valid = true;
+  ListBase *lb_iter;
+  FOREACH_MAIN_LISTBASE_BEGIN (bmain, lb_iter) {
+    LISTBASE_FOREACH_MUTABLE (ID *, id_iter, lb_iter) {
+      Uniqueness_Key key;
+      BLI_strncpy(key.name, id_iter->name, MAX_ID_NAME);
+      key.lib = id_iter->lib;
+      if (!id_names_libs.add(key)) {
+        is_valid = false;
+        CLOG_ERROR(&LOG,
+                   "ID name '%s' (from library '%s') is found more than once",
+                   id_iter->name,
+                   id_iter->lib != nullptr ? id_iter->lib->filepath : "");
+        if (do_fix) {
+          /* NOTE: this may imply moving this ID in its listbase, however re-checking it later is
+           * not really an issue. */
+          BKE_id_new_name_validate(
+              bmain, which_libbase(bmain, GS(id_iter->name)), id_iter, nullptr, true);
+          BLI_strncpy(key.name, id_iter->name, MAX_ID_NAME);
+          if (!id_names_libs.add(key)) {
+            CLOG_ERROR(&LOG,
+                       "\tID has been renamed to '%s', but it still seems to be already in use",
+                       id_iter->name);
+          }
+          else {
+            CLOG_WARN(&LOG, "\tID has been renamed to '%s'", id_iter->name);
+          }
+        }
+      }
+
+      UniqueName_Map *name_map = get_namemap_for(bmain, id_iter, false);
+      if (name_map == nullptr) {
+        continue;
+      }
+      UniqueName_TypeMap *type_map = name_map->find_by_type(GS(id_iter->name));
+      BLI_assert(type_map != nullptr);
+
+      UniqueName_Key key_namemap;
+      /* Remove full name from the set. */
+      BLI_strncpy(key_namemap.name, id_iter->name + 2, MAX_NAME);
+      if (!type_map->full_names.contains(key_namemap)) {
+        is_valid = false;
+        CLOG_ERROR(&LOG,
+                   "ID name '%s' (from library '%s') exists in current Main, but is not listed in "
+                   "the namemap",
+                   id_iter->name,
+                   id_iter->lib != nullptr ? id_iter->lib->filepath : "");
+      }
+    }
+  }
+  FOREACH_MAIN_LISTBASE_END;
+
+  Library *lib = nullptr;
+  UniqueName_Map *name_map = bmain->name_map;
+  do {
+    if (name_map != nullptr) {
+      int i = 0;
+      for (short idcode = BKE_idtype_idcode_iter_step(&i); idcode != 0;
+           idcode = BKE_idtype_idcode_iter_step(&i)) {
+        UniqueName_TypeMap *type_map = name_map->find_by_type(idcode);
+        if (type_map != nullptr) {
+          for (const UniqueName_Key &id_name : type_map->full_names) {
+            Uniqueness_Key key;
+            *(reinterpret_cast(key.name)) = idcode;
+            BLI_strncpy(key.name + 2, id_name.name, MAX_NAME);
+            key.lib = lib;
+            if (!id_names_libs.contains(key)) {
+              is_valid = false;
+              CLOG_ERROR(&LOG,
+                         "ID name '%s' (from library '%s') is listed in the namemap, but does not "
+                         "exists in current Main",
+                         key.name,
+                         lib != nullptr ? lib->filepath : "");
+            }
+          }
+        }
+      }
+    }
+    lib = static_cast((lib == nullptr) ? bmain->libraries.first : lib->id.next);
+    name_map = (lib != nullptr) ? lib->runtime.name_map : nullptr;
+  } while (lib != nullptr);
+
+  if (is_valid || !do_fix) {
+    return is_valid;
+  }
+
+  /* Clear all existing namemaps. */
+  lib = nullptr;
+  UniqueName_Map **name_map_p = &bmain->name_map;
+  do {
+    BLI_assert(name_map_p != nullptr);
+    if (*name_map_p != nullptr) {
+      BKE_main_namemap_destroy(name_map_p);
+    }
+    lib = static_cast((lib == nullptr) ? bmain->libraries.first : lib->id.next);
+    name_map_p = (lib != nullptr) ? &lib->runtime.name_map : nullptr;
+  } while (lib != nullptr);
+
+  return is_valid;
+}
+
+bool BKE_main_namemap_validate_and_fix(Main *bmain)
+{
+  const bool is_valid = main_namemap_validate_and_fix(bmain, true);
+  BLI_assert(main_namemap_validate_and_fix(bmain, false));
+  return is_valid;
+}
+
+bool BKE_main_namemap_validate(Main *bmain)
+{
+  return main_namemap_validate_and_fix(bmain, false);
+}
diff --git a/source/blender/blenkernel/intern/mask.c b/source/blender/blenkernel/intern/mask.c
index 42e65a95404..0b8351efdf4 100644
--- a/source/blender/blenkernel/intern/mask.c
+++ b/source/blender/blenkernel/intern/mask.c
@@ -249,7 +249,7 @@ IDTypeInfo IDType_ID_MSK = {
     .foreach_id = mask_foreach_id,
     .foreach_cache = NULL,
     .foreach_path = NULL,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = mask_blend_write,
     .blend_read_data = mask_blend_read_data,
@@ -1579,7 +1579,7 @@ void BKE_mask_parent_init(MaskParent *parent)
   parent->id_type = ID_MC;
 }
 
-/* *** own animation/shapekey implementation ***
+/* *** own animation/shape-key implementation ***
  * BKE_mask_layer_shape_XXX */
 
 int BKE_mask_layer_shape_totvert(MaskLayer *masklay)
diff --git a/source/blender/blenkernel/intern/material.c b/source/blender/blenkernel/intern/material.c
index f899901b54e..3ea6dd3d735 100644
--- a/source/blender/blenkernel/intern/material.c
+++ b/source/blender/blenkernel/intern/material.c
@@ -102,6 +102,7 @@ static void material_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const
                      (ID **)&material_dst->nodetree,
                      flag_private_id_data);
     }
+    material_dst->nodetree->owner_id = &material_dst->id;
   }
 
   if ((flag & LIB_ID_COPY_NO_PREVIEW) == 0) {
@@ -255,7 +256,7 @@ IDTypeInfo IDType_ID_MA = {
     .foreach_id = material_foreach_id,
     .foreach_cache = NULL,
     .foreach_path = NULL,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = material_blend_write,
     .blend_read_data = material_blend_read_data,
@@ -852,7 +853,7 @@ void BKE_object_material_resize(Main *bmain, Object *ob, const short totcol, boo
     ob->mat = newmatar;
     ob->matbits = newmatbits;
   }
-  /* XXX(campbell): why not realloc on shrink? */
+  /* XXX(@campbellbarton): why not realloc on shrink? */
 
   ob->totcol = totcol;
   if (ob->totcol && ob->actcol == 0) {
@@ -899,9 +900,15 @@ void BKE_objects_materials_test_all(Main *bmain, ID *id)
   }
 
   BKE_main_lock(bmain);
+  int processed_objects = 0;
   for (ob = bmain->objects.first; ob; ob = ob->id.next) {
     if (ob->data == id) {
       BKE_object_material_resize(bmain, ob, *totcol, false);
+      processed_objects++;
+      BLI_assert(processed_objects <= id->us && processed_objects > 0);
+      if (processed_objects == id->us) {
+        break;
+      }
     }
   }
   BKE_main_unlock(bmain);
@@ -1962,8 +1969,8 @@ static void material_default_surface_init(Material *ma)
 {
   strcpy(ma->id.name, "MADefault Surface");
 
-  bNodeTree *ntree = ntreeAddTree(NULL, "Shader Nodetree", ntreeType_Shader->idname);
-  ma->nodetree = ntree;
+  bNodeTree *ntree = ntreeAddTreeEmbedded(
+      NULL, &ma->id, "Shader Nodetree", ntreeType_Shader->idname);
   ma->use_nodes = true;
 
   bNode *principled = nodeAddStaticNode(NULL, ntree, SH_NODE_BSDF_PRINCIPLED);
@@ -1990,8 +1997,8 @@ static void material_default_volume_init(Material *ma)
 {
   strcpy(ma->id.name, "MADefault Volume");
 
-  bNodeTree *ntree = ntreeAddTree(NULL, "Shader Nodetree", ntreeType_Shader->idname);
-  ma->nodetree = ntree;
+  bNodeTree *ntree = ntreeAddTreeEmbedded(
+      NULL, &ma->id, "Shader Nodetree", ntreeType_Shader->idname);
   ma->use_nodes = true;
 
   bNode *principled = nodeAddStaticNode(NULL, ntree, SH_NODE_VOLUME_PRINCIPLED);
@@ -2015,8 +2022,8 @@ static void material_default_holdout_init(Material *ma)
 {
   strcpy(ma->id.name, "MADefault Holdout");
 
-  bNodeTree *ntree = ntreeAddTree(NULL, "Shader Nodetree", ntreeType_Shader->idname);
-  ma->nodetree = ntree;
+  bNodeTree *ntree = ntreeAddTreeEmbedded(
+      NULL, &ma->id, "Shader Nodetree", ntreeType_Shader->idname);
   ma->use_nodes = true;
 
   bNode *holdout = nodeAddStaticNode(NULL, ntree, SH_NODE_HOLDOUT);
diff --git a/source/blender/blenkernel/intern/mball.c b/source/blender/blenkernel/intern/mball.c
deleted file mode 100644
index 2a1c940493c..00000000000
--- a/source/blender/blenkernel/intern/mball.c
+++ /dev/null
@@ -1,754 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later
- * Copyright 2001-2002 NaN Holding BV. All rights reserved. */
-
-/** \file
- * \ingroup bke
- *
- * MetaBalls are created from a single Object (with a name without number in it),
- * here the DispList and BoundBox also is located.
- * All objects with the same name (but with a number in it) are added to this.
- *
- * texture coordinates are patched within the displist
- */
-
-#include 
-#include 
-#include 
-#include 
-#include 
-#include 
-
-#include "MEM_guardedalloc.h"
-
-/* Allow using deprecated functionality for .blend file I/O. */
-#define DNA_DEPRECATED_ALLOW
-
-#include "DNA_defaults.h"
-#include "DNA_material_types.h"
-#include "DNA_meta_types.h"
-#include "DNA_object_types.h"
-#include "DNA_scene_types.h"
-
-#include "BLI_blenlib.h"
-#include "BLI_math.h"
-#include "BLI_string_utils.h"
-#include "BLI_utildefines.h"
-
-#include "BLT_translation.h"
-
-#include "BKE_main.h"
-
-#include "BKE_anim_data.h"
-#include "BKE_curve.h"
-#include "BKE_displist.h"
-#include "BKE_idtype.h"
-#include "BKE_lib_id.h"
-#include "BKE_lib_query.h"
-#include "BKE_material.h"
-#include "BKE_mball.h"
-#include "BKE_object.h"
-#include "BKE_scene.h"
-
-#include "DEG_depsgraph.h"
-
-#include "BLO_read_write.h"
-
-static void metaball_init_data(ID *id)
-{
-  MetaBall *metaball = (MetaBall *)id;
-
-  BLI_assert(MEMCMP_STRUCT_AFTER_IS_ZERO(metaball, id));
-
-  MEMCPY_STRUCT_AFTER(metaball, DNA_struct_default_get(MetaBall), id);
-}
-
-static void metaball_copy_data(Main *UNUSED(bmain),
-                               ID *id_dst,
-                               const ID *id_src,
-                               const int UNUSED(flag))
-{
-  MetaBall *metaball_dst = (MetaBall *)id_dst;
-  const MetaBall *metaball_src = (const MetaBall *)id_src;
-
-  BLI_duplicatelist(&metaball_dst->elems, &metaball_src->elems);
-
-  metaball_dst->mat = MEM_dupallocN(metaball_src->mat);
-
-  metaball_dst->editelems = NULL;
-  metaball_dst->lastelem = NULL;
-  metaball_dst->batch_cache = NULL;
-}
-
-static void metaball_free_data(ID *id)
-{
-  MetaBall *metaball = (MetaBall *)id;
-
-  BKE_mball_batch_cache_free(metaball);
-
-  MEM_SAFE_FREE(metaball->mat);
-
-  BLI_freelistN(&metaball->elems);
-  if (metaball->disp.first) {
-    BKE_displist_free(&metaball->disp);
-  }
-}
-
-static void metaball_foreach_id(ID *id, LibraryForeachIDData *data)
-{
-  MetaBall *metaball = (MetaBall *)id;
-  for (int i = 0; i < metaball->totcol; i++) {
-    BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, metaball->mat[i], IDWALK_CB_USER);
-  }
-}
-
-static void metaball_blend_write(BlendWriter *writer, ID *id, const void *id_address)
-{
-  MetaBall *mb = (MetaBall *)id;
-
-  /* Clean up, important in undo case to reduce false detection of changed datablocks. */
-  BLI_listbase_clear(&mb->disp);
-  mb->editelems = NULL;
-  /* Must always be cleared (meta's don't have their own edit-data). */
-  mb->needs_flush_to_id = 0;
-  mb->lastelem = NULL;
-  mb->batch_cache = NULL;
-
-  /* write LibData */
-  BLO_write_id_struct(writer, MetaBall, id_address, &mb->id);
-  BKE_id_blend_write(writer, &mb->id);
-
-  /* direct data */
-  BLO_write_pointer_array(writer, mb->totcol, mb->mat);
-  if (mb->adt) {
-    BKE_animdata_blend_write(writer, mb->adt);
-  }
-
-  LISTBASE_FOREACH (MetaElem *, ml, &mb->elems) {
-    BLO_write_struct(writer, MetaElem, ml);
-  }
-}
-
-static void metaball_blend_read_data(BlendDataReader *reader, ID *id)
-{
-  MetaBall *mb = (MetaBall *)id;
-  BLO_read_data_address(reader, &mb->adt);
-  BKE_animdata_blend_read_data(reader, mb->adt);
-
-  BLO_read_pointer_array(reader, (void **)&mb->mat);
-
-  BLO_read_list(reader, &(mb->elems));
-
-  BLI_listbase_clear(&mb->disp);
-  mb->editelems = NULL;
-  /* Must always be cleared (meta's don't have their own edit-data). */
-  mb->needs_flush_to_id = 0;
-  // mb->edit_elems.first = mb->edit_elems.last = NULL;
-  mb->lastelem = NULL;
-  mb->batch_cache = NULL;
-}
-
-static void metaball_blend_read_lib(BlendLibReader *reader, ID *id)
-{
-  MetaBall *mb = (MetaBall *)id;
-  for (int a = 0; a < mb->totcol; a++) {
-    BLO_read_id_address(reader, mb->id.lib, &mb->mat[a]);
-  }
-
-  BLO_read_id_address(reader, mb->id.lib, &mb->ipo);  // XXX deprecated - old animation system
-}
-
-static void metaball_blend_read_expand(BlendExpander *expander, ID *id)
-{
-  MetaBall *mb = (MetaBall *)id;
-  for (int a = 0; a < mb->totcol; a++) {
-    BLO_expand(expander, mb->mat[a]);
-  }
-}
-
-IDTypeInfo IDType_ID_MB = {
-    .id_code = ID_MB,
-    .id_filter = FILTER_ID_MB,
-    .main_listbase_index = INDEX_ID_MB,
-    .struct_size = sizeof(MetaBall),
-    .name = "Metaball",
-    .name_plural = "metaballs",
-    .translation_context = BLT_I18NCONTEXT_ID_METABALL,
-    .flags = IDTYPE_FLAGS_APPEND_IS_REUSABLE,
-    .asset_type_info = NULL,
-
-    .init_data = metaball_init_data,
-    .copy_data = metaball_copy_data,
-    .free_data = metaball_free_data,
-    .make_local = NULL,
-    .foreach_id = metaball_foreach_id,
-    .foreach_cache = NULL,
-    .foreach_path = NULL,
-    .owner_get = NULL,
-
-    .blend_write = metaball_blend_write,
-    .blend_read_data = metaball_blend_read_data,
-    .blend_read_lib = metaball_blend_read_lib,
-    .blend_read_expand = metaball_blend_read_expand,
-
-    .blend_read_undo_preserve = NULL,
-
-    .lib_override_apply_post = NULL,
-};
-
-/* Functions */
-
-MetaBall *BKE_mball_add(Main *bmain, const char *name)
-{
-  MetaBall *mb;
-
-  mb = BKE_id_new(bmain, ID_MB, name);
-
-  return mb;
-}
-
-MetaElem *BKE_mball_element_add(MetaBall *mb, const int type)
-{
-  MetaElem *ml = MEM_callocN(sizeof(MetaElem), "metaelem");
-
-  unit_qt(ml->quat);
-
-  ml->rad = 2.0;
-  ml->s = 2.0;
-  ml->flag = MB_SCALE_RAD;
-
-  switch (type) {
-    case MB_BALL:
-      ml->type = MB_BALL;
-      ml->expx = ml->expy = ml->expz = 1.0;
-
-      break;
-    case MB_TUBE:
-      ml->type = MB_TUBE;
-      ml->expx = ml->expy = ml->expz = 1.0;
-
-      break;
-    case MB_PLANE:
-      ml->type = MB_PLANE;
-      ml->expx = ml->expy = ml->expz = 1.0;
-
-      break;
-    case MB_ELIPSOID:
-      ml->type = MB_ELIPSOID;
-      ml->expx = 1.2f;
-      ml->expy = 0.8f;
-      ml->expz = 1.0;
-
-      break;
-    case MB_CUBE:
-      ml->type = MB_CUBE;
-      ml->expx = ml->expy = ml->expz = 1.0;
-
-      break;
-    default:
-      break;
-  }
-
-  BLI_addtail(&mb->elems, ml);
-
-  return ml;
-}
-void BKE_mball_texspace_calc(Object *ob)
-{
-  DispList *dl;
-  BoundBox *bb;
-  float *data, min[3], max[3] /*, loc[3], size[3] */;
-  int tot;
-  bool do_it = false;
-
-  if (ob->runtime.bb == NULL) {
-    ob->runtime.bb = MEM_callocN(sizeof(BoundBox), "mb boundbox");
-  }
-  bb = ob->runtime.bb;
-
-  /* Weird one, this. */
-  // INIT_MINMAX(min, max);
-  (min)[0] = (min)[1] = (min)[2] = 1.0e30f;
-  (max)[0] = (max)[1] = (max)[2] = -1.0e30f;
-
-  dl = ob->runtime.curve_cache->disp.first;
-  while (dl) {
-    tot = dl->nr;
-    if (tot) {
-      do_it = true;
-    }
-    data = dl->verts;
-    while (tot--) {
-      /* Also weird... but longer. From utildefines. */
-      minmax_v3v3_v3(min, max, data);
-      data += 3;
-    }
-    dl = dl->next;
-  }
-
-  if (!do_it) {
-    min[0] = min[1] = min[2] = -1.0f;
-    max[0] = max[1] = max[2] = 1.0f;
-  }
-
-  BKE_boundbox_init_from_minmax(bb, min, max);
-
-  bb->flag &= ~BOUNDBOX_DIRTY;
-}
-
-BoundBox *BKE_mball_boundbox_get(Object *ob)
-{
-  BLI_assert(ob->type == OB_MBALL);
-
-  if (ob->runtime.bb != NULL && (ob->runtime.bb->flag & BOUNDBOX_DIRTY) == 0) {
-    return ob->runtime.bb;
-  }
-
-  /* This should always only be called with evaluated objects,
-   * but currently RNA is a problem here... */
-  if (ob->runtime.curve_cache != NULL) {
-    BKE_mball_texspace_calc(ob);
-  }
-
-  return ob->runtime.bb;
-}
-
-float *BKE_mball_make_orco(Object *ob, ListBase *dispbase)
-{
-  BoundBox *bb;
-  DispList *dl;
-  float *data, *orco, *orcodata;
-  float loc[3], size[3];
-  int a;
-
-  /* restore size and loc */
-  bb = ob->runtime.bb;
-  loc[0] = (bb->vec[0][0] + bb->vec[4][0]) / 2.0f;
-  size[0] = bb->vec[4][0] - loc[0];
-  loc[1] = (bb->vec[0][1] + bb->vec[2][1]) / 2.0f;
-  size[1] = bb->vec[2][1] - loc[1];
-  loc[2] = (bb->vec[0][2] + bb->vec[1][2]) / 2.0f;
-  size[2] = bb->vec[1][2] - loc[2];
-
-  dl = dispbase->first;
-  orcodata = MEM_mallocN(sizeof(float[3]) * dl->nr, "MballOrco");
-
-  data = dl->verts;
-  orco = orcodata;
-  a = dl->nr;
-  while (a--) {
-    orco[0] = (data[0] - loc[0]) / size[0];
-    orco[1] = (data[1] - loc[1]) / size[1];
-    orco[2] = (data[2] - loc[2]) / size[2];
-
-    data += 3;
-    orco += 3;
-  }
-
-  return orcodata;
-}
-
-bool BKE_mball_is_basis(const Object *ob)
-{
-  /* Meta-Ball Basis Notes from Blender-2.5x
-   * =======================================
-   *
-   * NOTE(@campbellbarton): This is a can of worms.
-   *
-   * This really needs a rewrite/refactor its totally broken in anything other than basic cases
-   * Multiple Scenes + Set Scenes & mixing meta-ball basis _should_ work but fails to update the
-   * depsgraph on rename and linking into scenes or removal of basis meta-ball.
-   * So take care when changing this code.
-   *
-   * Main idiot thing here is that the system returns #BKE_mball_basis_find()
-   * objects which fail a #BKE_mball_is_basis() test.
-   *
-   * Not only that but the depsgraph and their areas depend on this behavior,
-   * so making small fixes here isn't worth it. */
-
-  /* Just a quick test. */
-  const int len = strlen(ob->id.name);
-  return (!isdigit(ob->id.name[len - 1]));
-}
-
-bool BKE_mball_is_same_group(const Object *ob1, const Object *ob2)
-{
-  int basis1nr, basis2nr;
-  char basis1name[MAX_ID_NAME], basis2name[MAX_ID_NAME];
-
-  if (ob1->id.name[2] != ob2->id.name[2]) {
-    /* Quick return in case first char of both ID's names is not the same... */
-    return false;
-  }
-
-  BLI_split_name_num(basis1name, &basis1nr, ob1->id.name + 2, '.');
-  BLI_split_name_num(basis2name, &basis2nr, ob2->id.name + 2, '.');
-
-  return STREQ(basis1name, basis2name);
-}
-
-bool BKE_mball_is_basis_for(const Object *ob1, const Object *ob2)
-{
-  return BKE_mball_is_same_group(ob1, ob2) && BKE_mball_is_basis(ob1);
-}
-
-bool BKE_mball_is_any_selected(const MetaBall *mb)
-{
-  for (const MetaElem *ml = mb->editelems->first; ml != NULL; ml = ml->next) {
-    if (ml->flag & SELECT) {
-      return true;
-    }
-  }
-  return false;
-}
-
-bool BKE_mball_is_any_selected_multi(Base **bases, int bases_len)
-{
-  for (uint base_index = 0; base_index < bases_len; base_index++) {
-    Object *obedit = bases[base_index]->object;
-    MetaBall *mb = (MetaBall *)obedit->data;
-    if (BKE_mball_is_any_selected(mb)) {
-      return true;
-    }
-  }
-  return false;
-}
-
-bool BKE_mball_is_any_unselected(const MetaBall *mb)
-{
-  for (const MetaElem *ml = mb->editelems->first; ml != NULL; ml = ml->next) {
-    if ((ml->flag & SELECT) == 0) {
-      return true;
-    }
-  }
-  return false;
-}
-
-static void mball_data_properties_copy(MetaBall *mb_dst, MetaBall *mb_src)
-{
-  mb_dst->wiresize = mb_src->wiresize;
-  mb_dst->rendersize = mb_src->rendersize;
-  mb_dst->thresh = mb_src->thresh;
-  mb_dst->flag = mb_src->flag;
-  DEG_id_tag_update(&mb_dst->id, 0);
-}
-
-void BKE_mball_properties_copy(Main *bmain, MetaBall *metaball_src)
-{
-  /**
-   * WARNING: This code does not cover all potential corner-cases. E.g. if:
-   * 
-   * |   Object   |   ObData   |
-   * | ---------- | ---------- |
-   * | Meta_A     | Meta_A     |
-   * | Meta_A.001 | Meta_A.001 |
-   * | Meta_B     | Meta_A     |
-   * | Meta_B.001 | Meta_B.001 |
-   * 

-   *
-   * Calling this function with `metaball_src` being `Meta_A.001` will update `Meta_A`, but NOT
-   * `Meta_B.001`. So in the 'Meta_B' family, the two metaballs will have unmatching settings now.
-   *
-   * Solving this case would drastically increase the complexity of this code though, so don't
-   * think it would be worth it.
-   */
-  for (Object *ob_src = bmain->objects.first; ob_src != NULL && !ID_IS_LINKED(ob_src);) {
-    if (ob_src->data != metaball_src) {
-      ob_src = ob_src->id.next;
-      continue;
-    }
-
-    /* In this code we take advantage of two facts:
-     *  - MetaBalls of the same family have the same basis name,
-     *  - IDs are sorted by name in their Main listbase.
-     * So, all MetaBall objects of the same family are contiguous in bmain list (potentially mixed
-     * with non-meta-ball objects with same basis names).
-     *
-     * Using this, it is possible to process the whole set of meta-balls with a single loop on the
-     * whole list of Objects, though additionally going backward on part of the list in some cases.
-     */
-    Object *ob_iter = NULL;
-    int obactive_nr, ob_nr;
-    char obactive_name[MAX_ID_NAME], ob_name[MAX_ID_NAME];
-    BLI_split_name_num(obactive_name, &obactive_nr, ob_src->id.name + 2, '.');
-
-    for (ob_iter = ob_src->id.prev; ob_iter != NULL; ob_iter = ob_iter->id.prev) {
-      if (ob_iter->id.name[2] != obactive_name[0]) {
-        break;
-      }
-      if (ob_iter->type != OB_MBALL || ob_iter->data == metaball_src) {
-        continue;
-      }
-      BLI_split_name_num(ob_name, &ob_nr, ob_iter->id.name + 2, '.');
-      if (!STREQ(obactive_name, ob_name)) {
-        break;
-      }
-
-      mball_data_properties_copy(ob_iter->data, metaball_src);
-    }
-
-    for (ob_iter = ob_src->id.next; ob_iter != NULL; ob_iter = ob_iter->id.next) {
-      if (ob_iter->id.name[2] != obactive_name[0] || ID_IS_LINKED(ob_iter)) {
-        break;
-      }
-      if (ob_iter->type != OB_MBALL || ob_iter->data == metaball_src) {
-        continue;
-      }
-      BLI_split_name_num(ob_name, &ob_nr, ob_iter->id.name + 2, '.');
-      if (!STREQ(obactive_name, ob_name)) {
-        break;
-      }
-
-      mball_data_properties_copy(ob_iter->data, metaball_src);
-    }
-
-    ob_src = ob_iter;
-  }
-}
-
-Object *BKE_mball_basis_find(Scene *scene, Object *object)
-{
-  Object *bob = object;
-  int basisnr, obnr;
-  char basisname[MAX_ID_NAME], obname[MAX_ID_NAME];
-
-  BLI_split_name_num(basisname, &basisnr, object->id.name + 2, '.');
-
-  LISTBASE_FOREACH (ViewLayer *, view_layer, &scene->view_layers) {
-    LISTBASE_FOREACH (Base *, base, &view_layer->object_bases) {
-      Object *ob = base->object;
-      if ((ob->type == OB_MBALL) && !(base->flag & BASE_FROM_DUPLI)) {
-        if (ob != bob) {
-          BLI_split_name_num(obname, &obnr, ob->id.name + 2, '.');
-
-          /* Object ob has to be in same "group" ... it means,
-           * that it has to have same base of its name. */
-          if (STREQ(obname, basisname)) {
-            if (obnr < basisnr) {
-              object = ob;
-              basisnr = obnr;
-            }
-          }
-        }
-      }
-    }
-  }
-
-  return object;
-}
-
-bool BKE_mball_minmax_ex(
-    const MetaBall *mb, float min[3], float max[3], const float obmat[4][4], const short flag)
-{
-  const float scale = obmat ? mat4_to_scale(obmat) : 1.0f;
-  bool changed = false;
-  float centroid[3], vec[3];
-
-  INIT_MINMAX(min, max);
-
-  LISTBASE_FOREACH (const MetaElem *, ml, &mb->elems) {
-    if ((ml->flag & flag) == flag) {
-      const float scale_mb = (ml->rad * 0.5f) * scale;
-
-      if (obmat) {
-        mul_v3_m4v3(centroid, obmat, &ml->x);
-      }
-      else {
-        copy_v3_v3(centroid, &ml->x);
-      }
-
-      /* TODO(campbell): non circle shapes cubes etc, probably nobody notices. */
-      for (int i = -1; i != 3; i += 2) {
-        copy_v3_v3(vec, centroid);
-        add_v3_fl(vec, scale_mb * i);
-        minmax_v3v3_v3(min, max, vec);
-      }
-      changed = true;
-    }
-  }
-
-  return changed;
-}
-
-bool BKE_mball_minmax(const MetaBall *mb, float min[3], float max[3])
-{
-  INIT_MINMAX(min, max);
-
-  LISTBASE_FOREACH (const MetaElem *, ml, &mb->elems) {
-    minmax_v3v3_v3(min, max, &ml->x);
-  }
-
-  return (BLI_listbase_is_empty(&mb->elems) == false);
-}
-
-bool BKE_mball_center_median(const MetaBall *mb, float r_cent[3])
-{
-  int total = 0;
-
-  zero_v3(r_cent);
-
-  LISTBASE_FOREACH (const MetaElem *, ml, &mb->elems) {
-    add_v3_v3(r_cent, &ml->x);
-    total++;
-  }
-
-  if (total) {
-    mul_v3_fl(r_cent, 1.0f / (float)total);
-  }
-
-  return (total != 0);
-}
-
-bool BKE_mball_center_bounds(const MetaBall *mb, float r_cent[3])
-{
-  float min[3], max[3];
-
-  if (BKE_mball_minmax(mb, min, max)) {
-    mid_v3_v3v3(r_cent, min, max);
-    return true;
-  }
-
-  return false;
-}
-
-void BKE_mball_transform(MetaBall *mb, const float mat[4][4], const bool do_props)
-{
-  float quat[4];
-  const float scale = mat4_to_scale(mat);
-  const float scale_sqrt = sqrtf(scale);
-
-  mat4_to_quat(quat, mat);
-
-  LISTBASE_FOREACH (MetaElem *, ml, &mb->elems) {
-    mul_m4_v3(mat, &ml->x);
-    mul_qt_qtqt(ml->quat, quat, ml->quat);
-
-    if (do_props) {
-      ml->rad *= scale;
-      /* hrmf, probably elems shouldn't be
-       * treating scale differently - campbell */
-      if (!MB_TYPE_SIZE_SQUARED(ml->type)) {
-        mul_v3_fl(&ml->expx, scale);
-      }
-      else {
-        mul_v3_fl(&ml->expx, scale_sqrt);
-      }
-    }
-  }
-}
-
-void BKE_mball_translate(MetaBall *mb, const float offset[3])
-{
-  LISTBASE_FOREACH (MetaElem *, ml, &mb->elems) {
-    add_v3_v3(&ml->x, offset);
-  }
-}
-
-int BKE_mball_select_count(const MetaBall *mb)
-{
-  int sel = 0;
-  LISTBASE_FOREACH (const MetaElem *, ml, mb->editelems) {
-    if (ml->flag & SELECT) {
-      sel++;
-    }
-  }
-  return sel;
-}
-
-int BKE_mball_select_count_multi(Base **bases, int bases_len)
-{
-  int sel = 0;
-  for (uint ob_index = 0; ob_index < bases_len; ob_index++) {
-    const Object *obedit = bases[ob_index]->object;
-    const MetaBall *mb = (MetaBall *)obedit->data;
-    sel += BKE_mball_select_count(mb);
-  }
-  return sel;
-}
-
-bool BKE_mball_select_all(MetaBall *mb)
-{
-  bool changed = false;
-  LISTBASE_FOREACH (MetaElem *, ml, mb->editelems) {
-    if ((ml->flag & SELECT) == 0) {
-      ml->flag |= SELECT;
-      changed = true;
-    }
-  }
-  return changed;
-}
-
-bool BKE_mball_select_all_multi_ex(Base **bases, int bases_len)
-{
-  bool changed_multi = false;
-  for (uint ob_index = 0; ob_index < bases_len; ob_index++) {
-    Object *obedit = bases[ob_index]->object;
-    MetaBall *mb = obedit->data;
-    changed_multi |= BKE_mball_select_all(mb);
-  }
-  return changed_multi;
-}
-
-bool BKE_mball_deselect_all(MetaBall *mb)
-{
-  bool changed = false;
-  LISTBASE_FOREACH (MetaElem *, ml, mb->editelems) {
-    if ((ml->flag & SELECT) != 0) {
-      ml->flag &= ~SELECT;
-      changed = true;
-    }
-  }
-  return changed;
-}
-
-bool BKE_mball_deselect_all_multi_ex(Base **bases, int bases_len)
-{
-  bool changed_multi = false;
-  for (uint ob_index = 0; ob_index < bases_len; ob_index++) {
-    Object *obedit = bases[ob_index]->object;
-    MetaBall *mb = obedit->data;
-    changed_multi |= BKE_mball_deselect_all(mb);
-    DEG_id_tag_update(&mb->id, ID_RECALC_SELECT);
-  }
-  return changed_multi;
-}
-
-bool BKE_mball_select_swap(MetaBall *mb)
-{
-  bool changed = false;
-  LISTBASE_FOREACH (MetaElem *, ml, mb->editelems) {
-    ml->flag ^= SELECT;
-    changed = true;
-  }
-  return changed;
-}
-
-bool BKE_mball_select_swap_multi_ex(Base **bases, int bases_len)
-{
-  bool changed_multi = false;
-  for (uint ob_index = 0; ob_index < bases_len; ob_index++) {
-    Object *obedit = bases[ob_index]->object;
-    MetaBall *mb = (MetaBall *)obedit->data;
-    changed_multi |= BKE_mball_select_swap(mb);
-  }
-  return changed_multi;
-}
-
-/* **** Depsgraph evaluation **** */
-
-/* Draw Engine */
-
-void (*BKE_mball_batch_cache_dirty_tag_cb)(MetaBall *mb, int mode) = NULL;
-void (*BKE_mball_batch_cache_free_cb)(MetaBall *mb) = NULL;
-
-void BKE_mball_batch_cache_dirty_tag(MetaBall *mb, int mode)
-{
-  if (mb->batch_cache) {
-    BKE_mball_batch_cache_dirty_tag_cb(mb, mode);
-  }
-}
-void BKE_mball_batch_cache_free(MetaBall *mb)
-{
-  if (mb->batch_cache) {
-    BKE_mball_batch_cache_free_cb(mb);
-  }
-}
diff --git a/source/blender/blenkernel/intern/mball.cc b/source/blender/blenkernel/intern/mball.cc
new file mode 100644
index 00000000000..91797f8ed2f
--- /dev/null
+++ b/source/blender/blenkernel/intern/mball.cc
@@ -0,0 +1,715 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright 2001-2002 NaN Holding BV. All rights reserved. */
+
+/** \file
+ * \ingroup bke
+ *
+ * MetaBalls are created from a single Object (with a name without number in it).
+ * All objects with the same name (but with a number in it) are added to this.
+ */
+
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+
+#include "MEM_guardedalloc.h"
+
+/* Allow using deprecated functionality for .blend file I/O. */
+#define DNA_DEPRECATED_ALLOW
+
+#include "DNA_defaults.h"
+#include "DNA_material_types.h"
+#include "DNA_mesh_types.h"
+#include "DNA_meta_types.h"
+#include "DNA_object_types.h"
+#include "DNA_scene_types.h"
+
+#include "BLI_blenlib.h"
+#include "BLI_math.h"
+#include "BLI_string_utils.h"
+#include "BLI_utildefines.h"
+
+#include "BLT_translation.h"
+
+#include "BKE_main.h"
+
+#include "BKE_anim_data.h"
+#include "BKE_curve.h"
+#include "BKE_displist.h"
+#include "BKE_geometry_set.hh"
+#include "BKE_idtype.h"
+#include "BKE_lattice.h"
+#include "BKE_layer.h"
+#include "BKE_lib_id.h"
+#include "BKE_lib_query.h"
+#include "BKE_material.h"
+#include "BKE_mball.h"
+#include "BKE_mball_tessellate.h"
+#include "BKE_mesh.h"
+#include "BKE_object.h"
+#include "BKE_scene.h"
+
+#include "DEG_depsgraph.h"
+
+#include "BLO_read_write.h"
+
+static void metaball_init_data(ID *id)
+{
+  MetaBall *metaball = (MetaBall *)id;
+
+  BLI_assert(MEMCMP_STRUCT_AFTER_IS_ZERO(metaball, id));
+
+  MEMCPY_STRUCT_AFTER(metaball, DNA_struct_default_get(MetaBall), id);
+}
+
+static void metaball_copy_data(Main *UNUSED(bmain),
+                               ID *id_dst,
+                               const ID *id_src,
+                               const int UNUSED(flag))
+{
+  MetaBall *metaball_dst = (MetaBall *)id_dst;
+  const MetaBall *metaball_src = (const MetaBall *)id_src;
+
+  BLI_duplicatelist(&metaball_dst->elems, &metaball_src->elems);
+
+  metaball_dst->mat = static_cast(MEM_dupallocN(metaball_src->mat));
+
+  metaball_dst->editelems = nullptr;
+  metaball_dst->lastelem = nullptr;
+}
+
+static void metaball_free_data(ID *id)
+{
+  MetaBall *metaball = (MetaBall *)id;
+
+  MEM_SAFE_FREE(metaball->mat);
+
+  BLI_freelistN(&metaball->elems);
+  if (metaball->disp.first) {
+    BKE_displist_free(&metaball->disp);
+  }
+}
+
+static void metaball_foreach_id(ID *id, LibraryForeachIDData *data)
+{
+  MetaBall *metaball = (MetaBall *)id;
+  for (int i = 0; i < metaball->totcol; i++) {
+    BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, metaball->mat[i], IDWALK_CB_USER);
+  }
+}
+
+static void metaball_blend_write(BlendWriter *writer, ID *id, const void *id_address)
+{
+  MetaBall *mb = (MetaBall *)id;
+
+  /* Clean up, important in undo case to reduce false detection of changed datablocks. */
+  BLI_listbase_clear(&mb->disp);
+  mb->editelems = nullptr;
+  /* Must always be cleared (meta's don't have their own edit-data). */
+  mb->needs_flush_to_id = 0;
+  mb->lastelem = nullptr;
+
+  /* write LibData */
+  BLO_write_id_struct(writer, MetaBall, id_address, &mb->id);
+  BKE_id_blend_write(writer, &mb->id);
+
+  /* direct data */
+  BLO_write_pointer_array(writer, mb->totcol, mb->mat);
+  if (mb->adt) {
+    BKE_animdata_blend_write(writer, mb->adt);
+  }
+
+  LISTBASE_FOREACH (MetaElem *, ml, &mb->elems) {
+    BLO_write_struct(writer, MetaElem, ml);
+  }
+}
+
+static void metaball_blend_read_data(BlendDataReader *reader, ID *id)
+{
+  MetaBall *mb = (MetaBall *)id;
+  BLO_read_data_address(reader, &mb->adt);
+  BKE_animdata_blend_read_data(reader, mb->adt);
+
+  BLO_read_pointer_array(reader, (void **)&mb->mat);
+
+  BLO_read_list(reader, &(mb->elems));
+
+  BLI_listbase_clear(&mb->disp);
+  mb->editelems = nullptr;
+  /* Must always be cleared (meta's don't have their own edit-data). */
+  mb->needs_flush_to_id = 0;
+  // mb->edit_elems.first = mb->edit_elems.last = nullptr;
+  mb->lastelem = nullptr;
+}
+
+static void metaball_blend_read_lib(BlendLibReader *reader, ID *id)
+{
+  MetaBall *mb = (MetaBall *)id;
+  for (int a = 0; a < mb->totcol; a++) {
+    BLO_read_id_address(reader, mb->id.lib, &mb->mat[a]);
+  }
+
+  BLO_read_id_address(reader, mb->id.lib, &mb->ipo);  // XXX deprecated - old animation system
+}
+
+static void metaball_blend_read_expand(BlendExpander *expander, ID *id)
+{
+  MetaBall *mb = (MetaBall *)id;
+  for (int a = 0; a < mb->totcol; a++) {
+    BLO_expand(expander, mb->mat[a]);
+  }
+}
+
+IDTypeInfo IDType_ID_MB = {
+    /* id_code */ ID_MB,
+    /* id_filter */ FILTER_ID_MB,
+    /* main_listbase_index */ INDEX_ID_MB,
+    /* struct_size */ sizeof(MetaBall),
+    /* name */ "Metaball",
+    /* name_plural */ "metaballs",
+    /* translation_context */ BLT_I18NCONTEXT_ID_METABALL,
+    /* flags */ IDTYPE_FLAGS_APPEND_IS_REUSABLE,
+    /* asset_type_info */ nullptr,
+
+    /* init_data */ metaball_init_data,
+    /* copy_data */ metaball_copy_data,
+    /* free_data */ metaball_free_data,
+    /* make_local */ nullptr,
+    /* foreach_id */ metaball_foreach_id,
+    /* foreach_cache */ nullptr,
+    /* foreach_path */ nullptr,
+    /* owner_pointer_get */ nullptr,
+
+    /* blend_write */ metaball_blend_write,
+    /* blend_read_data */ metaball_blend_read_data,
+    /* blend_read_lib */ metaball_blend_read_lib,
+    /* blend_read_expand */ metaball_blend_read_expand,
+
+    /* blend_read_undo_preserve */ nullptr,
+
+    /* lib_override_apply_post */ nullptr,
+};
+
+/* Functions */
+
+MetaBall *BKE_mball_add(Main *bmain, const char *name)
+{
+  MetaBall *mb = static_cast(BKE_id_new(bmain, ID_MB, name));
+  return mb;
+}
+
+MetaElem *BKE_mball_element_add(MetaBall *mb, const int type)
+{
+  MetaElem *ml = MEM_cnew(__func__);
+
+  unit_qt(ml->quat);
+
+  ml->rad = 2.0;
+  ml->s = 2.0;
+  ml->flag = MB_SCALE_RAD;
+
+  switch (type) {
+    case MB_BALL:
+      ml->type = MB_BALL;
+      ml->expx = ml->expy = ml->expz = 1.0;
+
+      break;
+    case MB_TUBE:
+      ml->type = MB_TUBE;
+      ml->expx = ml->expy = ml->expz = 1.0;
+
+      break;
+    case MB_PLANE:
+      ml->type = MB_PLANE;
+      ml->expx = ml->expy = ml->expz = 1.0;
+
+      break;
+    case MB_ELIPSOID:
+      ml->type = MB_ELIPSOID;
+      ml->expx = 1.2f;
+      ml->expy = 0.8f;
+      ml->expz = 1.0;
+
+      break;
+    case MB_CUBE:
+      ml->type = MB_CUBE;
+      ml->expx = ml->expy = ml->expz = 1.0;
+
+      break;
+    default:
+      break;
+  }
+
+  BLI_addtail(&mb->elems, ml);
+
+  return ml;
+}
+
+BoundBox *BKE_mball_boundbox_get(Object *ob)
+{
+  BLI_assert(ob->type == OB_MBALL);
+  if (ob->runtime.bb != nullptr && (ob->runtime.bb->flag & BOUNDBOX_DIRTY) == 0) {
+    return ob->runtime.bb;
+  }
+  if (ob->runtime.bb == nullptr) {
+    ob->runtime.bb = MEM_cnew(__func__);
+  }
+
+  /* Expect that this function is only called for evaluated objects. */
+  const Mesh *mesh_eval = BKE_object_get_evaluated_mesh(ob);
+  float min[3];
+  float max[3];
+  if (mesh_eval) {
+    INIT_MINMAX(min, max);
+    if (!BKE_mesh_minmax(mesh_eval, min, max)) {
+      copy_v3_fl(min, -1.0f);
+      copy_v3_fl(max, 1.0f);
+    }
+  }
+  else {
+    copy_v3_fl(min, 0.0f);
+    copy_v3_fl(max, 0.0f);
+  }
+
+  BKE_boundbox_init_from_minmax(ob->runtime.bb, min, max);
+  ob->runtime.bb->flag &= ~BOUNDBOX_DIRTY;
+
+  return ob->runtime.bb;
+}
+
+bool BKE_mball_is_basis(const Object *ob)
+{
+  /* Meta-Ball Basis Notes from Blender-2.5x
+   * =======================================
+   *
+   * NOTE(@campbellbarton): This is a can of worms.
+   *
+   * This really needs a rewrite/refactor its totally broken in anything other than basic cases
+   * Multiple Scenes + Set Scenes & mixing meta-ball basis _should_ work but fails to update the
+   * depsgraph on rename and linking into scenes or removal of basis meta-ball.
+   * So take care when changing this code.
+   *
+   * Main idiot thing here is that the system returns #BKE_mball_basis_find()
+   * objects which fail a #BKE_mball_is_basis() test.
+   *
+   * Not only that but the depsgraph and their areas depend on this behavior,
+   * so making small fixes here isn't worth it. */
+
+  /* Just a quick test. */
+  const int len = strlen(ob->id.name);
+  return (!isdigit(ob->id.name[len - 1]));
+}
+
+bool BKE_mball_is_same_group(const Object *ob1, const Object *ob2)
+{
+  int basis1nr, basis2nr;
+  char basis1name[MAX_ID_NAME], basis2name[MAX_ID_NAME];
+
+  if (ob1->id.name[2] != ob2->id.name[2]) {
+    /* Quick return in case first char of both ID's names is not the same... */
+    return false;
+  }
+
+  BLI_split_name_num(basis1name, &basis1nr, ob1->id.name + 2, '.');
+  BLI_split_name_num(basis2name, &basis2nr, ob2->id.name + 2, '.');
+
+  return STREQ(basis1name, basis2name);
+}
+
+bool BKE_mball_is_basis_for(const Object *ob1, const Object *ob2)
+{
+  return BKE_mball_is_same_group(ob1, ob2) && BKE_mball_is_basis(ob1);
+}
+
+bool BKE_mball_is_any_selected(const MetaBall *mb)
+{
+  LISTBASE_FOREACH (const MetaElem *, ml, mb->editelems) {
+    if (ml->flag & SELECT) {
+      return true;
+    }
+  }
+  return false;
+}
+
+bool BKE_mball_is_any_selected_multi(Base **bases, int bases_len)
+{
+  for (uint base_index = 0; base_index < bases_len; base_index++) {
+    Object *obedit = bases[base_index]->object;
+    MetaBall *mb = (MetaBall *)obedit->data;
+    if (BKE_mball_is_any_selected(mb)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+bool BKE_mball_is_any_unselected(const MetaBall *mb)
+{
+  LISTBASE_FOREACH (const MetaElem *, ml, mb->editelems) {
+    if ((ml->flag & SELECT) == 0) {
+      return true;
+    }
+  }
+  return false;
+}
+
+static void mball_data_properties_copy(MetaBall *mb_dst, MetaBall *mb_src)
+{
+  mb_dst->wiresize = mb_src->wiresize;
+  mb_dst->rendersize = mb_src->rendersize;
+  mb_dst->thresh = mb_src->thresh;
+  mb_dst->flag = mb_src->flag;
+  DEG_id_tag_update(&mb_dst->id, 0);
+}
+
+void BKE_mball_properties_copy(Main *bmain, MetaBall *metaball_src)
+{
+  /**
+   * WARNING: This code does not cover all potential corner-cases. E.g. if:
+   * 
+   * |   Object   |   ObData   |
+   * | ---------- | ---------- |
+   * | Meta_A     | Meta_A     |
+   * | Meta_A.001 | Meta_A.001 |
+   * | Meta_B     | Meta_A     |
+   * | Meta_B.001 | Meta_B.001 |
+   * 

+   *
+   * Calling this function with `metaball_src` being `Meta_A.001` will update `Meta_A`, but NOT
+   * `Meta_B.001`. So in the 'Meta_B' family, the two metaballs will have unmatching settings now.
+   *
+   * Solving this case would drastically increase the complexity of this code though, so don't
+   * think it would be worth it.
+   */
+  for (Object *ob_src = static_cast(bmain->objects.first);
+       ob_src != nullptr && !ID_IS_LINKED(ob_src);) {
+    if (ob_src->data != metaball_src) {
+      ob_src = static_cast(ob_src->id.next);
+      continue;
+    }
+
+    /* In this code we take advantage of two facts:
+     *  - MetaBalls of the same family have the same basis name,
+     *  - IDs are sorted by name in their Main listbase.
+     * So, all MetaBall objects of the same family are contiguous in bmain list (potentially mixed
+     * with non-meta-ball objects with same basis names).
+     *
+     * Using this, it is possible to process the whole set of meta-balls with a single loop on the
+     * whole list of Objects, though additionally going backward on part of the list in some cases.
+     */
+    Object *ob_iter = nullptr;
+    int obactive_nr, ob_nr;
+    char obactive_name[MAX_ID_NAME], ob_name[MAX_ID_NAME];
+    BLI_split_name_num(obactive_name, &obactive_nr, ob_src->id.name + 2, '.');
+
+    for (ob_iter = static_cast(ob_src->id.prev); ob_iter != nullptr;
+         ob_iter = static_cast(ob_iter->id.prev)) {
+      if (ob_iter->id.name[2] != obactive_name[0]) {
+        break;
+      }
+      if (ob_iter->type != OB_MBALL || ob_iter->data == metaball_src) {
+        continue;
+      }
+      BLI_split_name_num(ob_name, &ob_nr, ob_iter->id.name + 2, '.');
+      if (!STREQ(obactive_name, ob_name)) {
+        break;
+      }
+
+      mball_data_properties_copy(static_cast(ob_iter->data), metaball_src);
+    }
+
+    for (ob_iter = static_cast(ob_src->id.next); ob_iter != nullptr;
+         ob_iter = static_cast(ob_iter->id.next)) {
+      if (ob_iter->id.name[2] != obactive_name[0] || ID_IS_LINKED(ob_iter)) {
+        break;
+      }
+      if (ob_iter->type != OB_MBALL || ob_iter->data == metaball_src) {
+        continue;
+      }
+      BLI_split_name_num(ob_name, &ob_nr, ob_iter->id.name + 2, '.');
+      if (!STREQ(obactive_name, ob_name)) {
+        break;
+      }
+
+      mball_data_properties_copy(static_cast(ob_iter->data), metaball_src);
+    }
+
+    ob_src = ob_iter;
+  }
+}
+
+Object *BKE_mball_basis_find(Scene *scene, Object *object)
+{
+  Object *bob = object;
+  int basisnr, obnr;
+  char basisname[MAX_ID_NAME], obname[MAX_ID_NAME];
+
+  BLI_split_name_num(basisname, &basisnr, object->id.name + 2, '.');
+
+  LISTBASE_FOREACH (ViewLayer *, view_layer, &scene->view_layers) {
+    BKE_view_layer_synced_ensure(scene, view_layer);
+    LISTBASE_FOREACH (Base *, base, BKE_view_layer_object_bases_get(view_layer)) {
+      Object *ob = base->object;
+      if ((ob->type == OB_MBALL) && !(base->flag & BASE_FROM_DUPLI)) {
+        if (ob != bob) {
+          BLI_split_name_num(obname, &obnr, ob->id.name + 2, '.');
+
+          /* Object ob has to be in same "group" ... it means,
+           * that it has to have same base of its name. */
+          if (STREQ(obname, basisname)) {
+            if (obnr < basisnr) {
+              object = ob;
+              basisnr = obnr;
+            }
+          }
+        }
+      }
+    }
+  }
+
+  return object;
+}
+
+bool BKE_mball_minmax_ex(
+    const MetaBall *mb, float min[3], float max[3], const float obmat[4][4], const short flag)
+{
+  const float scale = obmat ? mat4_to_scale(obmat) : 1.0f;
+  bool changed = false;
+  float centroid[3], vec[3];
+
+  INIT_MINMAX(min, max);
+
+  LISTBASE_FOREACH (const MetaElem *, ml, &mb->elems) {
+    if ((ml->flag & flag) == flag) {
+      const float scale_mb = (ml->rad * 0.5f) * scale;
+
+      if (obmat) {
+        mul_v3_m4v3(centroid, obmat, &ml->x);
+      }
+      else {
+        copy_v3_v3(centroid, &ml->x);
+      }
+
+      /* TODO(@campbellbarton): non circle shapes cubes etc, probably nobody notices. */
+      for (int i = -1; i != 3; i += 2) {
+        copy_v3_v3(vec, centroid);
+        add_v3_fl(vec, scale_mb * i);
+        minmax_v3v3_v3(min, max, vec);
+      }
+      changed = true;
+    }
+  }
+
+  return changed;
+}
+
+bool BKE_mball_minmax(const MetaBall *mb, float min[3], float max[3])
+{
+  INIT_MINMAX(min, max);
+
+  LISTBASE_FOREACH (const MetaElem *, ml, &mb->elems) {
+    minmax_v3v3_v3(min, max, &ml->x);
+  }
+
+  return (BLI_listbase_is_empty(&mb->elems) == false);
+}
+
+bool BKE_mball_center_median(const MetaBall *mb, float r_cent[3])
+{
+  int total = 0;
+
+  zero_v3(r_cent);
+
+  LISTBASE_FOREACH (const MetaElem *, ml, &mb->elems) {
+    add_v3_v3(r_cent, &ml->x);
+    total++;
+  }
+
+  if (total) {
+    mul_v3_fl(r_cent, 1.0f / (float)total);
+  }
+
+  return (total != 0);
+}
+
+bool BKE_mball_center_bounds(const MetaBall *mb, float r_cent[3])
+{
+  float min[3], max[3];
+
+  if (BKE_mball_minmax(mb, min, max)) {
+    mid_v3_v3v3(r_cent, min, max);
+    return true;
+  }
+
+  return false;
+}
+
+void BKE_mball_transform(MetaBall *mb, const float mat[4][4], const bool do_props)
+{
+  float quat[4];
+  const float scale = mat4_to_scale(mat);
+  const float scale_sqrt = sqrtf(scale);
+
+  mat4_to_quat(quat, mat);
+
+  LISTBASE_FOREACH (MetaElem *, ml, &mb->elems) {
+    mul_m4_v3(mat, &ml->x);
+    mul_qt_qtqt(ml->quat, quat, ml->quat);
+
+    if (do_props) {
+      ml->rad *= scale;
+      /* hrmf, probably elems shouldn't be
+       * treating scale differently - campbell */
+      if (!MB_TYPE_SIZE_SQUARED(ml->type)) {
+        mul_v3_fl(&ml->expx, scale);
+      }
+      else {
+        mul_v3_fl(&ml->expx, scale_sqrt);
+      }
+    }
+  }
+}
+
+void BKE_mball_translate(MetaBall *mb, const float offset[3])
+{
+  LISTBASE_FOREACH (MetaElem *, ml, &mb->elems) {
+    add_v3_v3(&ml->x, offset);
+  }
+}
+
+int BKE_mball_select_count(const MetaBall *mb)
+{
+  int sel = 0;
+  LISTBASE_FOREACH (const MetaElem *, ml, mb->editelems) {
+    if (ml->flag & SELECT) {
+      sel++;
+    }
+  }
+  return sel;
+}
+
+int BKE_mball_select_count_multi(Base **bases, int bases_len)
+{
+  int sel = 0;
+  for (uint ob_index = 0; ob_index < bases_len; ob_index++) {
+    const Object *obedit = bases[ob_index]->object;
+    const MetaBall *mb = (MetaBall *)obedit->data;
+    sel += BKE_mball_select_count(mb);
+  }
+  return sel;
+}
+
+bool BKE_mball_select_all(MetaBall *mb)
+{
+  bool changed = false;
+  LISTBASE_FOREACH (MetaElem *, ml, mb->editelems) {
+    if ((ml->flag & SELECT) == 0) {
+      ml->flag |= SELECT;
+      changed = true;
+    }
+  }
+  return changed;
+}
+
+bool BKE_mball_select_all_multi_ex(Base **bases, int bases_len)
+{
+  bool changed_multi = false;
+  for (uint ob_index = 0; ob_index < bases_len; ob_index++) {
+    Object *obedit = bases[ob_index]->object;
+    MetaBall *mb = static_cast(obedit->data);
+    changed_multi |= BKE_mball_select_all(mb);
+  }
+  return changed_multi;
+}
+
+bool BKE_mball_deselect_all(MetaBall *mb)
+{
+  bool changed = false;
+  LISTBASE_FOREACH (MetaElem *, ml, mb->editelems) {
+    if ((ml->flag & SELECT) != 0) {
+      ml->flag &= ~SELECT;
+      changed = true;
+    }
+  }
+  return changed;
+}
+
+bool BKE_mball_deselect_all_multi_ex(Base **bases, int bases_len)
+{
+  bool changed_multi = false;
+  for (uint ob_index = 0; ob_index < bases_len; ob_index++) {
+    Object *obedit = bases[ob_index]->object;
+    MetaBall *mb = static_cast(obedit->data);
+    changed_multi |= BKE_mball_deselect_all(mb);
+    DEG_id_tag_update(&mb->id, ID_RECALC_SELECT);
+  }
+  return changed_multi;
+}
+
+bool BKE_mball_select_swap(MetaBall *mb)
+{
+  bool changed = false;
+  LISTBASE_FOREACH (MetaElem *, ml, mb->editelems) {
+    ml->flag ^= SELECT;
+    changed = true;
+  }
+  return changed;
+}
+
+bool BKE_mball_select_swap_multi_ex(Base **bases, int bases_len)
+{
+  bool changed_multi = false;
+  for (uint ob_index = 0; ob_index < bases_len; ob_index++) {
+    Object *obedit = bases[ob_index]->object;
+    MetaBall *mb = (MetaBall *)obedit->data;
+    changed_multi |= BKE_mball_select_swap(mb);
+  }
+  return changed_multi;
+}
+
+/* **** Depsgraph evaluation **** */
+
+void BKE_mball_data_update(Depsgraph *depsgraph, Scene *scene, Object *ob)
+{
+  BLI_assert(ob->type == OB_MBALL);
+
+  BKE_object_free_derived_caches(ob);
+
+  const Object *basis_object = BKE_mball_basis_find(scene, ob);
+  if (ob != basis_object) {
+    return;
+  }
+
+  Mesh *mesh = BKE_mball_polygonize(depsgraph, scene, ob);
+  if (mesh == nullptr) {
+    return;
+  }
+
+  const MetaBall *mball = static_cast(ob->data);
+  mesh->mat = static_cast(MEM_dupallocN(mball->mat));
+  mesh->totcol = mball->totcol;
+
+  if (ob->parent && ob->parent->type == OB_LATTICE && ob->partype == PARSKEL) {
+    int verts_num;
+    float(*positions)[3] = BKE_mesh_vert_coords_alloc(mesh, &verts_num);
+    BKE_lattice_deform_coords(ob->parent, ob, positions, verts_num, 0, nullptr, 1.0f);
+    BKE_mesh_vert_coords_apply(mesh, positions);
+    MEM_freeN(positions);
+  }
+
+  ob->runtime.geometry_set_eval = new GeometrySet(GeometrySet::create_with_mesh(mesh));
+
+  if (ob->runtime.bb == nullptr) {
+    ob->runtime.bb = MEM_cnew(__func__);
+  }
+  blender::float3 min(std::numeric_limits::max());
+  blender::float3 max(-std::numeric_limits::max());
+  if (!ob->runtime.geometry_set_eval->compute_boundbox_without_instances(&min, &max)) {
+    min = blender::float3(0);
+    max = blender::float3(0);
+  }
+  BKE_boundbox_init_from_minmax(ob->runtime.bb, min, max);
+};
diff --git a/source/blender/blenkernel/intern/mball_tessellate.c b/source/blender/blenkernel/intern/mball_tessellate.c
index 54def0189b1..49963c333ec 100644
--- a/source/blender/blenkernel/intern/mball_tessellate.c
+++ b/source/blender/blenkernel/intern/mball_tessellate.c
@@ -14,6 +14,8 @@
 
 #include "MEM_guardedalloc.h"
 
+#include "DNA_mesh_types.h"
+#include "DNA_meshdata_types.h"
 #include "DNA_meta_types.h"
 #include "DNA_object_types.h"
 #include "DNA_scene_types.h"
@@ -24,10 +26,11 @@
 #include "BLI_string_utils.h"
 #include "BLI_utildefines.h"
 
-#include "BKE_global.h"
-
 #include "BKE_displist.h"
+#include "BKE_global.h"
+#include "BKE_lib_id.h"
 #include "BKE_mball_tessellate.h" /* own include */
+#include "BKE_mesh.h"
 #include "BKE_object.h"
 #include "BKE_scene.h"
 
@@ -427,8 +430,6 @@ static float metaball(PROCESS *process, float x, float y, float z)
  */
 static void make_face(PROCESS *process, int i1, int i2, int i3, int i4)
 {
-  int *cur;
-
 #ifdef USE_ACCUM_NORMAL
   float n[3];
 #endif
@@ -438,10 +439,9 @@ static void make_face(PROCESS *process, int i1, int i2, int i3, int i4)
     process->indices = MEM_reallocN(process->indices, sizeof(int[4]) * process->totindex);
   }
 
-  cur = process->indices[process->curindex++];
-
-  /* #DispList supports array drawing, treat tri's as fake quad. */
+  int *cur = process->indices[process->curindex++];
 
+  /* Treat triangles as fake quads. */
   cur[0] = i1;
   cur[1] = i2;
   cur[2] = i3;
@@ -1371,7 +1371,7 @@ static void init_meta(Depsgraph *depsgraph, PROCESS *process, Scene *scene, Obje
   }
 }
 
-void BKE_mball_polygonize(Depsgraph *depsgraph, Scene *scene, Object *ob, ListBase *dispbase)
+Mesh *BKE_mball_polygonize(Depsgraph *depsgraph, Scene *scene, Object *ob)
 {
   PROCESS process = {0};
   const bool is_render = DEG_get_mode(depsgraph) == DAG_EVAL_RENDER;
@@ -1394,10 +1394,10 @@ void BKE_mball_polygonize(Depsgraph *depsgraph, Scene *scene, Object *ob, ListBa
   }
 
   if (!is_render && (mb->flag == MB_UPDATE_NEVER)) {
-    return;
+    return NULL;
   }
   if ((G.moving & (G_TRANSFORM_OBJ | G_TRANSFORM_EDIT)) && mb->flag == MB_UPDATE_FAST) {
-    return;
+    return NULL;
   }
 
   if (is_render) {
@@ -1418,7 +1418,7 @@ void BKE_mball_polygonize(Depsgraph *depsgraph, Scene *scene, Object *ob, ListBa
   init_meta(depsgraph, &process, scene, ob);
   if (process.totelem == 0) {
     freepolygonize(&process);
-    return;
+    return NULL;
   }
 
   build_bvh_spatial(&process, &process.metaball_bvh, 0, process.totelem, &process.allbb);
@@ -1430,40 +1430,61 @@ void BKE_mball_polygonize(Depsgraph *depsgraph, Scene *scene, Object *ob, ListBa
       ob->scale[1] < 0.00001f * (process.allbb.max[1] - process.allbb.min[1]) ||
       ob->scale[2] < 0.00001f * (process.allbb.max[2] - process.allbb.min[2])) {
     freepolygonize(&process);
-    return;
+    return NULL;
   }
 
   polygonize(&process);
   if (process.curindex == 0) {
     freepolygonize(&process);
-    return;
+    return NULL;
   }
 
-  /* add resulting surface to displist */
+  freepolygonize(&process);
 
-  /* Avoid over-allocation since this is stored in the displist. */
-  if (process.curindex != process.totindex) {
-    process.indices = MEM_reallocN(process.indices, sizeof(int[4]) * process.curindex);
-  }
-  if (process.curvertex != process.totvertex) {
-    process.co = MEM_reallocN(process.co, process.curvertex * sizeof(float[3]));
-    process.no = MEM_reallocN(process.no, process.curvertex * sizeof(float[3]));
-  }
+  Mesh *mesh = (Mesh *)BKE_id_new_nomain(ID_ME, ((ID *)ob->data)->name + 2);
 
-  DispList *dl = MEM_callocN(sizeof(DispList), "mballdisp");
-  BLI_addtail(dispbase, dl);
-  dl->type = DL_INDEX4;
-  dl->nr = (int)process.curvertex;
-  dl->parts = (int)process.curindex;
+  mesh->totvert = (int)process.curvertex;
+  MVert *mvert = CustomData_add_layer(&mesh->vdata, CD_MVERT, CD_CONSTRUCT, NULL, mesh->totvert);
+  for (int i = 0; i < mesh->totvert; i++) {
+    copy_v3_v3(mvert[i].co, process.co[i]);
+    mvert->flag = 0;
+  }
+  MEM_freeN(process.co);
+
+  mesh->totpoly = (int)process.curindex;
+  MPoly *mpoly = CustomData_add_layer(&mesh->pdata, CD_MPOLY, CD_CONSTRUCT, NULL, mesh->totpoly);
+  MLoop *mloop = CustomData_add_layer(
+      &mesh->ldata, CD_MLOOP, CD_CONSTRUCT, NULL, mesh->totpoly * 4);
+
+  int loop_offset = 0;
+  for (int i = 0; i < mesh->totpoly; i++) {
+    const int *indices = process.indices[i];
+
+    const int count = indices[2] != indices[3] ? 4 : 3;
+    mpoly[i].loopstart = loop_offset;
+    mpoly[i].totloop = count;
+    mpoly[i].flag = ME_SMOOTH;
+
+    mloop[loop_offset].v = (uint32_t)indices[0];
+    mloop[loop_offset + 1].v = (uint32_t)indices[1];
+    mloop[loop_offset + 2].v = (uint32_t)indices[2];
+    if (count == 4) {
+      mloop[loop_offset + 3].v = (uint32_t)indices[3];
+    }
 
-  dl->index = (int *)process.indices;
+    loop_offset += count;
+  }
+  MEM_freeN(process.indices);
 
-  for (uint a = 0; a < process.curvertex; a++) {
-    normalize_v3(process.no[a]);
+  for (int i = 0; i < mesh->totvert; i++) {
+    normalize_v3(process.no[i]);
   }
+  mesh->runtime.vert_normals = process.no;
+  BKE_mesh_vertex_normals_clear_dirty(mesh);
 
-  dl->verts = (float *)process.co;
-  dl->nors = (float *)process.no;
+  mesh->totloop = loop_offset;
 
-  freepolygonize(&process);
+  BKE_mesh_calc_edges(mesh, false, false);
+
+  return mesh;
 }
diff --git a/source/blender/blenkernel/intern/mesh.cc b/source/blender/blenkernel/intern/mesh.cc
index 2a14370bf93..7da9acc3cf6 100644
--- a/source/blender/blenkernel/intern/mesh.cc
+++ b/source/blender/blenkernel/intern/mesh.cc
@@ -17,7 +17,7 @@
 #include "DNA_meshdata_types.h"
 #include "DNA_object_types.h"
 
-#include "BLI_bitmap.h"
+#include "BLI_bit_vector.hh"
 #include "BLI_edgehash.h"
 #include "BLI_endian_switch.h"
 #include "BLI_ghash.h"
@@ -28,14 +28,17 @@
 #include "BLI_math.h"
 #include "BLI_math_vector.hh"
 #include "BLI_memarena.h"
+#include "BLI_span.hh"
 #include "BLI_string.h"
 #include "BLI_task.hh"
 #include "BLI_utildefines.h"
 #include "BLI_vector.hh"
+#include "BLI_virtual_array.hh"
 
 #include "BLT_translation.h"
 
 #include "BKE_anim_data.h"
+#include "BKE_attribute.hh"
 #include "BKE_bpath.h"
 #include "BKE_deform.h"
 #include "BKE_editmesh.h"
@@ -61,7 +64,11 @@
 
 #include "BLO_read_write.h"
 
+using blender::BitVector;
 using blender::float3;
+using blender::MutableSpan;
+using blender::Span;
+using blender::VArray;
 using blender::Vector;
 
 static void mesh_clear_geometry(Mesh *mesh);
@@ -96,6 +103,10 @@ static void mesh_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const int
   const Mesh *mesh_src = (const Mesh *)id_src;
 
   BKE_mesh_runtime_reset_on_copy(mesh_dst, flag);
+  /* Copy face dot tags, since meshes may be duplicated after a subsurf modifier
+   * or node, but we still need to be able to draw face center vertices. */
+  mesh_dst->runtime.subsurf_face_dot_tags = static_cast(
+      MEM_dupallocN(mesh_src->runtime.subsurf_face_dot_tags));
   if ((mesh_src->id.tag & LIB_TAG_NO_MAIN) == 0) {
     /* This is a direct copy of a main mesh, so for now it has the same topology. */
     mesh_dst->runtime.deformed_only = true;
@@ -109,7 +120,7 @@ static void mesh_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const int
    *
    * While this could be the callers responsibility, keep here since it's
    * highly unlikely we want to create a duplicate and not use it for drawing. */
-  mesh_dst->runtime.is_original = false;
+  mesh_dst->runtime.is_original_bmesh = false;
 
   /* Only do tessface if we have no polys. */
   const bool do_tessface = ((mesh_src->totface != 0) && (mesh_src->totpoly == 0));
@@ -137,8 +148,6 @@ static void mesh_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const int
     mesh_tessface_clear_intern(mesh_dst, false);
   }
 
-  BKE_mesh_update_customdata_pointers(mesh_dst, do_tessface);
-
   mesh_dst->cd_flag = mesh_src->cd_flag;
 
   mesh_dst->edit_mesh = nullptr;
@@ -208,6 +217,7 @@ static void mesh_foreach_path(ID *id, BPathForeachPathData *bpath_data)
 
 static void mesh_blend_write(BlendWriter *writer, ID *id, const void *id_address)
 {
+  using namespace blender;
   Mesh *mesh = (Mesh *)id;
   const bool is_undo = BLO_write_is_undo(writer);
 
@@ -224,27 +234,39 @@ static void mesh_blend_write(BlendWriter *writer, ID *id, const void *id_address
 
   /* Do not store actual geometry data in case this is a library override ID. */
   if (ID_IS_OVERRIDE_LIBRARY(mesh) && !is_undo) {
-    mesh->mvert = nullptr;
     mesh->totvert = 0;
     memset(&mesh->vdata, 0, sizeof(mesh->vdata));
 
-    mesh->medge = nullptr;
     mesh->totedge = 0;
     memset(&mesh->edata, 0, sizeof(mesh->edata));
 
-    mesh->mloop = nullptr;
     mesh->totloop = 0;
     memset(&mesh->ldata, 0, sizeof(mesh->ldata));
 
-    mesh->mpoly = nullptr;
     mesh->totpoly = 0;
     memset(&mesh->pdata, 0, sizeof(mesh->pdata));
   }
   else {
-    CustomData_blend_write_prepare(mesh->vdata, vert_layers);
-    CustomData_blend_write_prepare(mesh->edata, edge_layers);
-    CustomData_blend_write_prepare(mesh->ldata, loop_layers);
-    CustomData_blend_write_prepare(mesh->pdata, poly_layers);
+    Set names_to_skip;
+    if (!BLO_write_is_undo(writer)) {
+      BKE_mesh_legacy_convert_hide_layers_to_flags(mesh);
+      BKE_mesh_legacy_convert_material_indices_to_mpoly(mesh);
+      BKE_mesh_legacy_bevel_weight_from_layers(mesh);
+      /* When converting to the old mesh format, don't save redundant attributes. */
+      names_to_skip.add_multiple_new({".hide_vert", ".hide_edge", ".hide_poly", "material_index"});
+
+      /* Set deprecated mesh data pointers for forward compatibility. */
+      mesh->mvert = const_cast(mesh->verts().data());
+      mesh->medge = const_cast(mesh->edges().data());
+      mesh->mpoly = const_cast(mesh->polys().data());
+      mesh->mloop = const_cast(mesh->loops().data());
+      mesh->dvert = const_cast(mesh->deform_verts().data());
+    }
+
+    CustomData_blend_write_prepare(mesh->vdata, vert_layers, names_to_skip);
+    CustomData_blend_write_prepare(mesh->edata, edge_layers, names_to_skip);
+    CustomData_blend_write_prepare(mesh->ldata, loop_layers, names_to_skip);
+    CustomData_blend_write_prepare(mesh->pdata, poly_layers, names_to_skip);
   }
 
   BLO_write_id_struct(writer, Mesh, id_address, &mesh->id);
@@ -277,26 +299,22 @@ static void mesh_blend_read_data(BlendDataReader *reader, ID *id)
   Mesh *mesh = (Mesh *)id;
   BLO_read_pointer_array(reader, (void **)&mesh->mat);
 
+  /* Deprecated pointers to custom data layers are read here for backward compatibility
+   * with files where these were owning pointers rather than a view into custom data. */
   BLO_read_data_address(reader, &mesh->mvert);
   BLO_read_data_address(reader, &mesh->medge);
   BLO_read_data_address(reader, &mesh->mface);
-  BLO_read_data_address(reader, &mesh->mloop);
-  BLO_read_data_address(reader, &mesh->mpoly);
-  BLO_read_data_address(reader, &mesh->tface);
   BLO_read_data_address(reader, &mesh->mtface);
-  BLO_read_data_address(reader, &mesh->mcol);
   BLO_read_data_address(reader, &mesh->dvert);
-  BLO_read_data_address(reader, &mesh->mloopcol);
-  BLO_read_data_address(reader, &mesh->mloopuv);
+  BLO_read_data_address(reader, &mesh->tface);
+  BLO_read_data_address(reader, &mesh->mcol);
+
   BLO_read_data_address(reader, &mesh->mselect);
 
   /* animdata */
   BLO_read_data_address(reader, &mesh->adt);
   BKE_animdata_blend_read_data(reader, mesh->adt);
 
-  /* Normally BKE_defvert_blend_read should be called in CustomData_blend_read,
-   * but for backwards compatibility in do_versions to work we do it here. */
-  BKE_defvert_blend_read(reader, mesh->totvert, mesh->dvert);
   BLO_read_list(reader, &mesh->vertex_group_names);
 
   CustomData_blend_read(reader, &mesh->vdata, mesh->totvert);
@@ -304,6 +322,11 @@ static void mesh_blend_read_data(BlendDataReader *reader, ID *id)
   CustomData_blend_read(reader, &mesh->fdata, mesh->totface);
   CustomData_blend_read(reader, &mesh->ldata, mesh->totloop);
   CustomData_blend_read(reader, &mesh->pdata, mesh->totpoly);
+  if (mesh->deform_verts().is_empty()) {
+    /* Vertex group data was also an owning pointer in old Blender versions.
+     * Don't read them again if they were read as part of #CustomData. */
+    BKE_defvert_blend_read(reader, mesh->totvert, mesh->dvert);
+  }
 
   mesh->texflag &= ~ME_AUTOSPACE_EVALUATED;
   mesh->edit_mesh = nullptr;
@@ -375,7 +398,7 @@ IDTypeInfo IDType_ID_ME = {
     /* foreach_id */ mesh_foreach_id,
     /* foreach_cache */ nullptr,
     /* foreach_path */ mesh_foreach_path,
-    /* owner_get */ nullptr,
+    /* owner_pointer_get */ nullptr,
 
     /* blend_write */ mesh_blend_write,
     /* blend_read_data */ mesh_blend_read_data,
@@ -445,6 +468,8 @@ static int customdata_compare(
                                        CD_MASK_MLOOPUV | CD_MASK_PROP_BYTE_COLOR |
                                        CD_MASK_MDEFORMVERT;
   const uint64_t cd_mask_all_attr = CD_MASK_PROP_ALL | cd_mask_non_generic;
+  const Span loops_1 = m1->loops();
+  const Span loops_2 = m2->loops();
 
   for (int i = 0; i < c1->totlayer; i++) {
     l1 = &c1->layers[i];
@@ -461,7 +486,8 @@ static int customdata_compare(
   }
 
   if (layer_count1 != layer_count2) {
-    return MESHCMP_CDLAYERS_MISMATCH;
+    /* TODO(@HooglyBoogly): Reenable after tests are updated for material index refactor. */
+    // return MESHCMP_CDLAYERS_MISMATCH;
   }
 
   l1 = c1->layers;
@@ -519,15 +545,14 @@ static int customdata_compare(
           int ptot = m1->totpoly;
 
           for (j = 0; j < ptot; j++, p1++, p2++) {
-            MLoop *lp1, *lp2;
             int k;
 
             if (p1->totloop != p2->totloop) {
               return MESHCMP_POLYMISMATCH;
             }
 
-            lp1 = m1->mloop + p1->loopstart;
-            lp2 = m2->mloop + p2->loopstart;
+            const MLoop *lp1 = &loops_1[p1->loopstart];
+            const MLoop *lp2 = &loops_2[p2->loopstart];
 
             for (k = 0; k < p1->totloop; k++, lp1++, lp2++) {
               if (lp1->v != lp2->v) {
@@ -738,47 +763,6 @@ const char *BKE_mesh_cmp(Mesh *me1, Mesh *me2, float thresh)
   return nullptr;
 }
 
-static void mesh_ensure_tessellation_customdata(Mesh *me)
-{
-  if (UNLIKELY((me->totface != 0) && (me->totpoly == 0))) {
-    /* Pass, otherwise this function  clears 'mface' before
-     * versioning 'mface -> mpoly' code kicks in T30583.
-     *
-     * Callers could also check but safer to do here - campbell */
-  }
-  else {
-    const int tottex_original = CustomData_number_of_layers(&me->ldata, CD_MLOOPUV);
-    const int totcol_original = CustomData_number_of_layers(&me->ldata, CD_PROP_BYTE_COLOR);
-
-    const int tottex_tessface = CustomData_number_of_layers(&me->fdata, CD_MTFACE);
-    const int totcol_tessface = CustomData_number_of_layers(&me->fdata, CD_MCOL);
-
-    if (tottex_tessface != tottex_original || totcol_tessface != totcol_original) {
-      BKE_mesh_tessface_clear(me);
-
-      BKE_mesh_add_mface_layers(&me->fdata, &me->ldata, me->totface);
-
-      /* TODO: add some `--debug-mesh` option. */
-      if (G.debug & G_DEBUG) {
-        /* NOTE(campbell): this warning may be un-called for if we are initializing the mesh for
-         * the first time from #BMesh, rather than giving a warning about this we could be smarter
-         * and check if there was any data to begin with, for now just print the warning with
-         * some info to help troubleshoot what's going on. */
-        printf(
-            "%s: warning! Tessellation uvs or vcol data got out of sync, "
-            "had to reset!\n    CD_MTFACE: %d != CD_MLOOPUV: %d || CD_MCOL: %d != "
-            "CD_PROP_BYTE_COLOR: "
-            "%d\n",
-            __func__,
-            tottex_tessface,
-            tottex_original,
-            totcol_tessface,
-            totcol_original);
-      }
-    }
-  }
-}
-
 void BKE_mesh_ensure_skin_customdata(Mesh *me)
 {
   BMesh *bm = me->edit_mesh ? me->edit_mesh->bm : nullptr;
@@ -802,7 +786,7 @@ void BKE_mesh_ensure_skin_customdata(Mesh *me)
   else {
     if (!CustomData_has_layer(&me->vdata, CD_MVERT_SKIN)) {
       vs = (MVertSkin *)CustomData_add_layer(
-          &me->vdata, CD_MVERT_SKIN, CD_DEFAULT, nullptr, me->totvert);
+          &me->vdata, CD_MVERT_SKIN, CD_SET_DEFAULT, nullptr, me->totvert);
 
       /* Mark an arbitrary vertex as root */
       if (vs) {
@@ -824,7 +808,7 @@ bool BKE_mesh_ensure_facemap_customdata(struct Mesh *me)
   }
   else {
     if (!CustomData_has_layer(&me->pdata, CD_FACEMAP)) {
-      CustomData_add_layer(&me->pdata, CD_FACEMAP, CD_DEFAULT, nullptr, me->totpoly);
+      CustomData_add_layer(&me->pdata, CD_FACEMAP, CD_SET_DEFAULT, nullptr, me->totpoly);
       changed = true;
     }
   }
@@ -850,43 +834,6 @@ bool BKE_mesh_clear_facemap_customdata(struct Mesh *me)
   return changed;
 }
 
-/**
- * This ensures grouped custom-data (e.g. #CD_MLOOPUV and #CD_MTFACE, or
- * #CD_PROP_BYTE_COLOR and #CD_MCOL) have the same relative active/render/clone/mask indices.
- *
- * NOTE(@campbellbarton): that for undo mesh data we want to skip 'ensure_tess_cd' call since
- * we don't want to store memory for #MFace data when its only used for older
- * versions of the mesh.
- */
-static void mesh_update_linked_customdata(Mesh *me, const bool do_ensure_tess_cd)
-{
-  if (do_ensure_tess_cd) {
-    mesh_ensure_tessellation_customdata(me);
-  }
-
-  CustomData_bmesh_update_active_layers(&me->fdata, &me->ldata);
-}
-
-void BKE_mesh_update_customdata_pointers(Mesh *me, const bool do_ensure_tess_cd)
-{
-  mesh_update_linked_customdata(me, do_ensure_tess_cd);
-
-  me->mvert = (MVert *)CustomData_get_layer(&me->vdata, CD_MVERT);
-  me->dvert = (MDeformVert *)CustomData_get_layer(&me->vdata, CD_MDEFORMVERT);
-
-  me->medge = (MEdge *)CustomData_get_layer(&me->edata, CD_MEDGE);
-
-  me->mface = (MFace *)CustomData_get_layer(&me->fdata, CD_MFACE);
-  me->mcol = (MCol *)CustomData_get_layer(&me->fdata, CD_MCOL);
-  me->mtface = (MTFace *)CustomData_get_layer(&me->fdata, CD_MTFACE);
-
-  me->mpoly = (MPoly *)CustomData_get_layer(&me->pdata, CD_MPOLY);
-  me->mloop = (MLoop *)CustomData_get_layer(&me->ldata, CD_MLOOP);
-
-  me->mloopcol = (MLoopCol *)CustomData_get_layer(&me->ldata, CD_PROP_BYTE_COLOR);
-  me->mloopuv = (MLoopUV *)CustomData_get_layer(&me->ldata, CD_MLOOPUV);
-}
-
 bool BKE_mesh_has_custom_loop_normals(Mesh *me)
 {
   if (me->edit_mesh) {
@@ -931,12 +878,11 @@ static void mesh_clear_geometry(Mesh *mesh)
   mesh->act_face = -1;
   mesh->totselect = 0;
 
-  BKE_mesh_update_customdata_pointers(mesh, false);
+  BLI_freelistN(&mesh->vertex_group_names);
 }
 
 void BKE_mesh_clear_geometry(Mesh *mesh)
 {
-  BKE_animdata_free(&mesh->id, false);
   BKE_mesh_runtime_clear_cache(mesh);
   mesh_clear_geometry(mesh);
 }
@@ -950,9 +896,6 @@ static void mesh_tessface_clear_intern(Mesh *mesh, int free_customdata)
     CustomData_reset(&mesh->fdata);
   }
 
-  mesh->mface = nullptr;
-  mesh->mtface = nullptr;
-  mesh->mcol = nullptr;
   mesh->totface = 0;
 }
 
@@ -967,20 +910,20 @@ Mesh *BKE_mesh_add(Main *bmain, const char *name)
 static void mesh_ensure_cdlayers_primary(Mesh *mesh, bool do_tessface)
 {
   if (!CustomData_get_layer(&mesh->vdata, CD_MVERT)) {
-    CustomData_add_layer(&mesh->vdata, CD_MVERT, CD_CALLOC, nullptr, mesh->totvert);
+    CustomData_add_layer(&mesh->vdata, CD_MVERT, CD_SET_DEFAULT, nullptr, mesh->totvert);
   }
   if (!CustomData_get_layer(&mesh->edata, CD_MEDGE)) {
-    CustomData_add_layer(&mesh->edata, CD_MEDGE, CD_CALLOC, nullptr, mesh->totedge);
+    CustomData_add_layer(&mesh->edata, CD_MEDGE, CD_SET_DEFAULT, nullptr, mesh->totedge);
   }
   if (!CustomData_get_layer(&mesh->ldata, CD_MLOOP)) {
-    CustomData_add_layer(&mesh->ldata, CD_MLOOP, CD_CALLOC, nullptr, mesh->totloop);
+    CustomData_add_layer(&mesh->ldata, CD_MLOOP, CD_SET_DEFAULT, nullptr, mesh->totloop);
   }
   if (!CustomData_get_layer(&mesh->pdata, CD_MPOLY)) {
-    CustomData_add_layer(&mesh->pdata, CD_MPOLY, CD_CALLOC, nullptr, mesh->totpoly);
+    CustomData_add_layer(&mesh->pdata, CD_MPOLY, CD_SET_DEFAULT, nullptr, mesh->totpoly);
   }
 
   if (do_tessface && !CustomData_get_layer(&mesh->fdata, CD_MFACE)) {
-    CustomData_add_layer(&mesh->fdata, CD_MFACE, CD_CALLOC, nullptr, mesh->totface);
+    CustomData_add_layer(&mesh->fdata, CD_MFACE, CD_SET_DEFAULT, nullptr, mesh->totface);
   }
 }
 
@@ -1005,7 +948,6 @@ Mesh *BKE_mesh_new_nomain(
   mesh->totpoly = polys_len;
 
   mesh_ensure_cdlayers_primary(mesh, true);
-  BKE_mesh_update_customdata_pointers(mesh, false);
 
   return mesh;
 }
@@ -1030,6 +972,7 @@ void BKE_mesh_copy_parameters(Mesh *me_dst, const Mesh *me_src)
   copy_v3_v3(me_dst->size, me_src->size);
 
   me_dst->vertex_group_active_index = me_src->vertex_group_active_index;
+  me_dst->attributes_active_index = me_src->attributes_active_index;
 }
 
 void BKE_mesh_copy_parameters_for_eval(Mesh *me_dst, const Mesh *me_src)
@@ -1077,12 +1020,12 @@ Mesh *BKE_mesh_new_nomain_from_template_ex(const Mesh *me_src,
   me_dst->cd_flag = me_src->cd_flag;
   BKE_mesh_copy_parameters_for_eval(me_dst, me_src);
 
-  CustomData_copy(&me_src->vdata, &me_dst->vdata, mask.vmask, CD_CALLOC, verts_len);
-  CustomData_copy(&me_src->edata, &me_dst->edata, mask.emask, CD_CALLOC, edges_len);
-  CustomData_copy(&me_src->ldata, &me_dst->ldata, mask.lmask, CD_CALLOC, loops_len);
-  CustomData_copy(&me_src->pdata, &me_dst->pdata, mask.pmask, CD_CALLOC, polys_len);
+  CustomData_copy(&me_src->vdata, &me_dst->vdata, mask.vmask, CD_SET_DEFAULT, verts_len);
+  CustomData_copy(&me_src->edata, &me_dst->edata, mask.emask, CD_SET_DEFAULT, edges_len);
+  CustomData_copy(&me_src->ldata, &me_dst->ldata, mask.lmask, CD_SET_DEFAULT, loops_len);
+  CustomData_copy(&me_src->pdata, &me_dst->pdata, mask.pmask, CD_SET_DEFAULT, polys_len);
   if (do_tessface) {
-    CustomData_copy(&me_src->fdata, &me_dst->fdata, mask.fmask, CD_CALLOC, tessface_len);
+    CustomData_copy(&me_src->fdata, &me_dst->fdata, mask.fmask, CD_SET_DEFAULT, tessface_len);
   }
   else {
     mesh_tessface_clear_intern(me_dst, false);
@@ -1091,7 +1034,6 @@ Mesh *BKE_mesh_new_nomain_from_template_ex(const Mesh *me_src,
   /* The destination mesh should at least have valid primary CD layers,
    * even in cases where the source mesh does not. */
   mesh_ensure_cdlayers_primary(me_dst, do_tessface);
-  BKE_mesh_update_customdata_pointers(me_dst, false);
 
   /* Expect that normals aren't copied at all, since the destination mesh is new. */
   BLI_assert(BKE_mesh_vertex_normals_are_dirty(me_dst));
@@ -1183,13 +1125,18 @@ static void ensure_orig_index_layer(CustomData &data, const int size)
   if (CustomData_has_layer(&data, CD_ORIGINDEX)) {
     return;
   }
-  int *indices = (int *)CustomData_add_layer(&data, CD_ORIGINDEX, CD_DEFAULT, nullptr, size);
+  int *indices = (int *)CustomData_add_layer(&data, CD_ORIGINDEX, CD_SET_DEFAULT, nullptr, size);
   range_vn_i(indices, size, 0);
 }
 
 void BKE_mesh_ensure_default_orig_index_customdata(Mesh *mesh)
 {
   BLI_assert(mesh->runtime.wrapper_type == ME_WRAPPER_TYPE_MDATA);
+  BKE_mesh_ensure_default_orig_index_customdata_no_check(mesh);
+}
+
+void BKE_mesh_ensure_default_orig_index_customdata_no_check(Mesh *mesh)
+{
   ensure_orig_index_layer(mesh->vdata, mesh->totvert);
   ensure_orig_index_layer(mesh->edata, mesh->totedge);
   ensure_orig_index_layer(mesh->pdata, mesh->totpoly);
@@ -1309,11 +1256,12 @@ float (*BKE_mesh_orco_verts_get(Object *ob))[3]
 
   /* Get appropriate vertex coordinates */
   float(*vcos)[3] = (float(*)[3])MEM_calloc_arrayN(me->totvert, sizeof(*vcos), "orco mesh");
-  MVert *mvert = tme->mvert;
+  const Span verts = tme->verts();
+
   int totvert = min_ii(tme->totvert, me->totvert);
 
-  for (int a = 0; a < totvert; a++, mvert++) {
-    copy_v3_v3(vcos[a], mvert->co);
+  for (int a = 0; a < totvert; a++) {
+    copy_v3_v3(vcos[a], verts[a].co);
   }
 
   return vcos;
@@ -1391,61 +1339,57 @@ void BKE_mesh_assign_object(Main *bmain, Object *ob, Mesh *me)
 
 void BKE_mesh_material_index_remove(Mesh *me, short index)
 {
-  MPoly *mp;
-  MFace *mf;
-  int i;
-
-  for (mp = me->mpoly, i = 0; i < me->totpoly; i++, mp++) {
-    if (mp->mat_nr && mp->mat_nr >= index) {
-      mp->mat_nr--;
-    }
+  using namespace blender;
+  using namespace blender::bke;
+  MutableAttributeAccessor attributes = me->attributes_for_write();
+  AttributeWriter material_indices = attributes.lookup_for_write("material_index");
+  if (!material_indices) {
+    return;
   }
-
-  for (mf = me->mface, i = 0; i < me->totface; i++, mf++) {
-    if (mf->mat_nr && mf->mat_nr >= index) {
-      mf->mat_nr--;
+  if (material_indices.domain != ATTR_DOMAIN_FACE) {
+    BLI_assert_unreachable();
+    return;
+  }
+  MutableVArraySpan indices_span(material_indices.varray);
+  for (const int i : indices_span.index_range()) {
+    if (indices_span[i] > 0 && indices_span[i] > index) {
+      indices_span[i]--;
     }
   }
+  indices_span.save();
+  material_indices.finish();
+
+  BKE_mesh_tessface_clear(me);
 }
 
 bool BKE_mesh_material_index_used(Mesh *me, short index)
 {
-  MPoly *mp;
-  MFace *mf;
-  int i;
-
-  for (mp = me->mpoly, i = 0; i < me->totpoly; i++, mp++) {
-    if (mp->mat_nr == index) {
-      return true;
-    }
-  }
-
-  for (mf = me->mface, i = 0; i < me->totface; i++, mf++) {
-    if (mf->mat_nr == index) {
-      return true;
-    }
+  using namespace blender;
+  using namespace blender::bke;
+  const AttributeAccessor attributes = me->attributes();
+  const VArray material_indices = attributes.lookup_or_default(
+      "material_index", ATTR_DOMAIN_FACE, 0);
+  if (material_indices.is_single()) {
+    return material_indices.get_internal_single() == index;
   }
-
-  return false;
+  const VArraySpan indices_span(material_indices);
+  return indices_span.contains(index);
 }
 
 void BKE_mesh_material_index_clear(Mesh *me)
 {
-  MPoly *mp;
-  MFace *mf;
-  int i;
-
-  for (mp = me->mpoly, i = 0; i < me->totpoly; i++, mp++) {
-    mp->mat_nr = 0;
-  }
+  using namespace blender;
+  using namespace blender::bke;
+  MutableAttributeAccessor attributes = me->attributes_for_write();
+  attributes.remove("material_index");
 
-  for (mf = me->mface, i = 0; i < me->totface; i++, mf++) {
-    mf->mat_nr = 0;
-  }
+  BKE_mesh_tessface_clear(me);
 }
 
 void BKE_mesh_material_remap(Mesh *me, const uint *remap, uint remap_len)
 {
+  using namespace blender;
+  using namespace blender::bke;
   const short remap_len_short = (short)remap_len;
 
 #define MAT_NR_REMAP(n) \
@@ -1465,10 +1409,17 @@ void BKE_mesh_material_remap(Mesh *me, const uint *remap, uint remap_len)
     }
   }
   else {
-    int i;
-    for (i = 0; i < me->totpoly; i++) {
-      MAT_NR_REMAP(me->mpoly[i].mat_nr);
+    MutableAttributeAccessor attributes = me->attributes_for_write();
+    SpanAttributeWriter material_indices = attributes.lookup_or_add_for_write_span(
+        "material_index", ATTR_DOMAIN_FACE);
+    if (!material_indices) {
+      return;
     }
+    for (const int i : material_indices.span.index_range()) {
+      MAT_NR_REMAP(material_indices.span[i]);
+    }
+    material_indices.span.save();
+    material_indices.finish();
   }
 
 #undef MAT_NR_REMAP
@@ -1476,14 +1427,15 @@ void BKE_mesh_material_remap(Mesh *me, const uint *remap, uint remap_len)
 
 void BKE_mesh_smooth_flag_set(Mesh *me, const bool use_smooth)
 {
+  MutableSpan polys = me->polys_for_write();
   if (use_smooth) {
-    for (int i = 0; i < me->totpoly; i++) {
-      me->mpoly[i].flag |= ME_SMOOTH;
+    for (MPoly &poly : polys) {
+      poly.flag |= ME_SMOOTH;
     }
   }
   else {
-    for (int i = 0; i < me->totpoly; i++) {
-      me->mpoly[i].flag &= ~ME_SMOOTH;
+    for (MPoly &poly : polys) {
+      poly.flag &= ~ME_SMOOTH;
     }
   }
 }
@@ -1539,9 +1491,12 @@ int BKE_mesh_edge_other_vert(const MEdge *e, int v)
 
 void BKE_mesh_looptri_get_real_edges(const Mesh *mesh, const MLoopTri *looptri, int r_edges[3])
 {
+  const Span edges = mesh->edges();
+  const Span loops = mesh->loops();
+
   for (int i = 2, i_next = 0; i_next < 3; i = i_next++) {
-    const MLoop *l1 = &mesh->mloop[looptri->tri[i]], *l2 = &mesh->mloop[looptri->tri[i_next]];
-    const MEdge *e = &mesh->medge[l1->e];
+    const MLoop *l1 = &loops[looptri->tri[i]], *l2 = &loops[looptri->tri[i_next]];
+    const MEdge *e = &edges[l1->e];
 
     bool is_real = (l1->v == e->v1 && l2->v == e->v2) || (l1->v == e->v2 && l2->v == e->v1);
 
@@ -1560,15 +1515,16 @@ bool BKE_mesh_minmax(const Mesh *me, float r_min[3], float r_max[3])
     float3 min;
     float3 max;
   };
+  const Span verts = me->verts();
 
   const Result minmax = threading::parallel_reduce(
-      IndexRange(me->totvert),
+      verts.index_range(),
       1024,
       Result{float3(FLT_MAX), float3(-FLT_MAX)},
-      [&](IndexRange range, const Result &init) {
+      [verts](IndexRange range, const Result &init) {
         Result result = init;
         for (const int i : range) {
-          math::min_max(float3(me->mvert[i].co), result.min, result.max);
+          math::min_max(float3(verts[i].co), result.min, result.max);
         }
         return result;
       },
@@ -1584,22 +1540,16 @@ bool BKE_mesh_minmax(const Mesh *me, float r_min[3], float r_max[3])
 
 void BKE_mesh_transform(Mesh *me, const float mat[4][4], bool do_keys)
 {
-  int i;
-  MVert *mvert = (MVert *)CustomData_duplicate_referenced_layer(&me->vdata, CD_MVERT, me->totvert);
-  float(*lnors)[3] = (float(*)[3])CustomData_duplicate_referenced_layer(
-      &me->ldata, CD_NORMAL, me->totloop);
+  MutableSpan verts = me->verts_for_write();
 
-  /* If the referenced layer has been re-allocated need to update pointers stored in the mesh. */
-  BKE_mesh_update_customdata_pointers(me, false);
-
-  for (i = 0; i < me->totvert; i++, mvert++) {
-    mul_m4_v3(mat, mvert->co);
+  for (MVert &vert : verts) {
+    mul_m4_v3(mat, vert.co);
   }
 
   if (do_keys && me->key) {
     LISTBASE_FOREACH (KeyBlock *, kb, &me->key->block) {
       float *fp = (float *)kb->data;
-      for (i = kb->totelem; i--; fp += 3) {
+      for (int i = kb->totelem; i--; fp += 3) {
         mul_m4_v3(mat, fp);
       }
     }
@@ -1608,12 +1558,14 @@ void BKE_mesh_transform(Mesh *me, const float mat[4][4], bool do_keys)
   /* don't update normals, caller can do this explicitly.
    * We do update loop normals though, those may not be auto-generated
    * (see e.g. STL import script)! */
+  float(*lnors)[3] = (float(*)[3])CustomData_duplicate_referenced_layer(
+      &me->ldata, CD_NORMAL, me->totloop);
   if (lnors) {
     float m3[3][3];
 
     copy_m3_m4(m3, mat);
     normalize_m3(m3);
-    for (i = 0; i < me->totloop; i++, lnors++) {
+    for (int i = 0; i < me->totloop; i++, lnors++) {
       mul_m3_v3(m3, *lnors);
     }
   }
@@ -1622,15 +1574,12 @@ void BKE_mesh_transform(Mesh *me, const float mat[4][4], bool do_keys)
 
 void BKE_mesh_translate(Mesh *me, const float offset[3], const bool do_keys)
 {
-  CustomData_duplicate_referenced_layer(&me->vdata, CD_MVERT, me->totvert);
-  /* If the referenced layer has been re-allocated need to update pointers stored in the mesh. */
-  BKE_mesh_update_customdata_pointers(me, false);
-
-  int i = me->totvert;
-  for (MVert *mvert = me->mvert; i--; mvert++) {
-    add_v3_v3(mvert->co, offset);
+  MutableSpan verts = me->verts_for_write();
+  for (MVert &vert : verts) {
+    add_v3_v3(vert.co, offset);
   }
 
+  int i;
   if (do_keys && me->key) {
     LISTBASE_FOREACH (KeyBlock *, kb, &me->key->block) {
       float *fp = (float *)kb->data;
@@ -1653,25 +1602,24 @@ void BKE_mesh_do_versions_cd_flag_init(Mesh *mesh)
     return;
   }
 
-  MVert *mv;
-  MEdge *med;
-  int i;
+  const Span verts = mesh->verts();
+  const Span edges = mesh->edges();
 
-  for (mv = mesh->mvert, i = 0; i < mesh->totvert; mv++, i++) {
-    if (mv->bweight != 0) {
+  for (const MVert &vert : verts) {
+    if (vert.bweight_legacy != 0) {
       mesh->cd_flag |= ME_CDFLAG_VERT_BWEIGHT;
       break;
     }
   }
 
-  for (med = mesh->medge, i = 0; i < mesh->totedge; med++, i++) {
-    if (med->bweight != 0) {
+  for (const MEdge &edge : edges) {
+    if (edge.bweight_legacy != 0) {
       mesh->cd_flag |= ME_CDFLAG_EDGE_BWEIGHT;
       if (mesh->cd_flag & ME_CDFLAG_EDGE_CREASE) {
         break;
       }
     }
-    if (med->crease != 0) {
+    if (edge.crease != 0) {
       mesh->cd_flag |= ME_CDFLAG_EDGE_CREASE;
       if (mesh->cd_flag & ME_CDFLAG_EDGE_BWEIGHT) {
         break;
@@ -1697,6 +1645,9 @@ void BKE_mesh_mselect_validate(Mesh *me)
   if (me->totselect == 0) {
     return;
   }
+  const Span verts = me->verts();
+  const Span edges = me->edges();
+  const Span polys = me->polys();
 
   mselect_src = me->mselect;
   mselect_dst = (MSelect *)MEM_malloc_arrayN(
@@ -1706,21 +1657,21 @@ void BKE_mesh_mselect_validate(Mesh *me)
     int index = mselect_src[i_src].index;
     switch (mselect_src[i_src].type) {
       case ME_VSEL: {
-        if (me->mvert[index].flag & SELECT) {
+        if (verts[index].flag & SELECT) {
           mselect_dst[i_dst] = mselect_src[i_src];
           i_dst++;
         }
         break;
       }
       case ME_ESEL: {
-        if (me->medge[index].flag & SELECT) {
+        if (edges[index].flag & SELECT) {
           mselect_dst[i_dst] = mselect_src[i_src];
           i_dst++;
         }
         break;
       }
       case ME_FSEL: {
-        if (me->mpoly[index].flag & SELECT) {
+        if (polys[index].flag & SELECT) {
           mselect_dst[i_dst] = mselect_src[i_src];
           i_dst++;
         }
@@ -1806,10 +1757,10 @@ void BKE_mesh_count_selected_items(const Mesh *mesh, int r_count[3])
 
 void BKE_mesh_vert_coords_get(const Mesh *mesh, float (*vert_coords)[3])
 {
-  const MVert *mv = mesh->mvert;
-  for (int i = 0; i < mesh->totvert; i++, mv++) {
-    copy_v3_v3(vert_coords[i], mv->co);
-  }
+  blender::bke::AttributeAccessor attributes = mesh->attributes();
+  VArray positions = attributes.lookup_or_default(
+      "position", ATTR_DOMAIN_POINT, float3(0));
+  positions.materialize({(float3 *)vert_coords, mesh->totvert});
 }
 
 float (*BKE_mesh_vert_coords_alloc(const Mesh *mesh, int *r_vert_len))[3]
@@ -1824,12 +1775,9 @@ float (*BKE_mesh_vert_coords_alloc(const Mesh *mesh, int *r_vert_len))[3]
 
 void BKE_mesh_vert_coords_apply(Mesh *mesh, const float (*vert_coords)[3])
 {
-  /* This will just return the pointer if it wasn't a referenced layer. */
-  MVert *mv = (MVert *)CustomData_duplicate_referenced_layer(
-      &mesh->vdata, CD_MVERT, mesh->totvert);
-  mesh->mvert = mv;
-  for (int i = 0; i < mesh->totvert; i++, mv++) {
-    copy_v3_v3(mv->co, vert_coords[i]);
+  MutableSpan verts = mesh->verts_for_write();
+  for (const int i : verts.index_range()) {
+    copy_v3_v3(verts[i].co, vert_coords[i]);
   }
   BKE_mesh_tag_coords_changed(mesh);
 }
@@ -1838,12 +1786,9 @@ void BKE_mesh_vert_coords_apply_with_mat4(Mesh *mesh,
                                           const float (*vert_coords)[3],
                                           const float mat[4][4])
 {
-  /* This will just return the pointer if it wasn't a referenced layer. */
-  MVert *mv = (MVert *)CustomData_duplicate_referenced_layer(
-      &mesh->vdata, CD_MVERT, mesh->totvert);
-  mesh->mvert = mv;
-  for (int i = 0; i < mesh->totvert; i++, mv++) {
-    mul_v3_m4v3(mv->co, mat, vert_coords[i]);
+  MutableSpan verts = mesh->verts_for_write();
+  for (const int i : verts.index_range()) {
+    mul_v3_m4v3(verts[i].co, mat, vert_coords[i]);
   }
   BKE_mesh_tag_coords_changed(mesh);
 }
@@ -1857,7 +1802,7 @@ static float (*ensure_corner_normal_layer(Mesh &mesh))[3]
   }
   else {
     r_loopnors = (float(*)[3])CustomData_add_layer(
-        &mesh.ldata, CD_NORMAL, CD_CALLOC, nullptr, mesh.totloop);
+        &mesh.ldata, CD_NORMAL, CD_SET_DEFAULT, nullptr, mesh.totloop);
     CustomData_set_layer_flag(&mesh.ldata, CD_NORMAL, CD_FLAG_TEMPORARY);
   }
   return r_loopnors;
@@ -1879,17 +1824,22 @@ void BKE_mesh_calc_normals_split_ex(Mesh *mesh,
   /* may be nullptr */
   clnors = (short(*)[2])CustomData_get_layer(&mesh->ldata, CD_CUSTOMLOOPNORMAL);
 
-  BKE_mesh_normals_loop_split(mesh->mvert,
+  const Span verts = mesh->verts();
+  const Span edges = mesh->edges();
+  const Span polys = mesh->polys();
+  const Span loops = mesh->loops();
+
+  BKE_mesh_normals_loop_split(verts.data(),
                               BKE_mesh_vertex_normals_ensure(mesh),
-                              mesh->totvert,
-                              mesh->medge,
-                              mesh->totedge,
-                              mesh->mloop,
+                              verts.size(),
+                              edges.data(),
+                              edges.size(),
+                              loops.data(),
                               r_corner_normals,
-                              mesh->totloop,
-                              mesh->mpoly,
+                              loops.size(),
+                              polys.data(),
                               BKE_mesh_poly_normals_ensure(mesh),
-                              mesh->totpoly,
+                              polys.size(),
                               use_split_normals,
                               split_angle,
                               r_lnors_spacearr,
@@ -1935,22 +1885,22 @@ static int split_faces_prepare_new_verts(Mesh *mesh,
 
   const int loops_len = mesh->totloop;
   int verts_len = mesh->totvert;
-  MLoop *mloop = mesh->mloop;
+  MutableSpan loops = mesh->loops_for_write();
   BKE_mesh_vertex_normals_ensure(mesh);
   float(*vert_normals)[3] = BKE_mesh_vertex_normals_for_write(mesh);
 
-  BLI_bitmap *verts_used = BLI_BITMAP_NEW(verts_len, __func__);
-  BLI_bitmap *done_loops = BLI_BITMAP_NEW(loops_len, __func__);
+  BitVector<> verts_used(verts_len, false);
+  BitVector<> done_loops(loops_len, false);
 
-  MLoop *ml = mloop;
+  MLoop *ml = loops.data();
   MLoopNorSpace **lnor_space = lnors_spacearr->lspacearr;
 
   BLI_assert(lnors_spacearr->data_type == MLNOR_SPACEARR_LOOP_INDEX);
 
   for (int loop_idx = 0; loop_idx < loops_len; loop_idx++, ml++, lnor_space++) {
-    if (!BLI_BITMAP_TEST(done_loops, loop_idx)) {
+    if (!done_loops[loop_idx]) {
       const int vert_idx = ml->v;
-      const bool vert_used = BLI_BITMAP_TEST_BOOL(verts_used, vert_idx);
+      const bool vert_used = verts_used[vert_idx];
       /* If vert is already used by another smooth fan, we need a new vert for this one. */
       const int new_vert_idx = vert_used ? verts_len++ : vert_idx;
 
@@ -1959,7 +1909,7 @@ static int split_faces_prepare_new_verts(Mesh *mesh,
       if ((*lnor_space)->flags & MLNOR_SPACE_IS_SINGLE) {
         /* Single loop in this fan... */
         BLI_assert(POINTER_AS_INT((*lnor_space)->loops) == loop_idx);
-        BLI_BITMAP_ENABLE(done_loops, loop_idx);
+        done_loops[loop_idx].set();
         if (vert_used) {
           ml->v = new_vert_idx;
         }
@@ -1967,15 +1917,15 @@ static int split_faces_prepare_new_verts(Mesh *mesh,
       else {
         for (LinkNode *lnode = (*lnor_space)->loops; lnode; lnode = lnode->next) {
           const int ml_fan_idx = POINTER_AS_INT(lnode->link);
-          BLI_BITMAP_ENABLE(done_loops, ml_fan_idx);
+          done_loops[ml_fan_idx].set();
           if (vert_used) {
-            mloop[ml_fan_idx].v = new_vert_idx;
+            loops[ml_fan_idx].v = new_vert_idx;
           }
         }
       }
 
       if (!vert_used) {
-        BLI_BITMAP_ENABLE(verts_used, vert_idx);
+        verts_used[vert_idx].set();
         /* We need to update that vertex's normal here, we won't go over it again. */
         /* This is important! *DO NOT* set vnor to final computed lnor,
          * vnor should always be defined to 'automatic normal' value computed from its polys,
@@ -1996,38 +1946,35 @@ static int split_faces_prepare_new_verts(Mesh *mesh,
     }
   }
 
-  MEM_freeN(done_loops);
-  MEM_freeN(verts_used);
-
   return verts_len - mesh->totvert;
 }
 
 /* Detect needed new edges, and update accordingly loops' edge indices.
  * WARNING! Leaves mesh in invalid state. */
-static int split_faces_prepare_new_edges(const Mesh *mesh,
+static int split_faces_prepare_new_edges(Mesh *mesh,
                                          SplitFaceNewEdge **new_edges,
                                          MemArena *memarena)
 {
   const int num_polys = mesh->totpoly;
   int num_edges = mesh->totedge;
-  MEdge *medge = mesh->medge;
-  MLoop *mloop = mesh->mloop;
-  const MPoly *mpoly = mesh->mpoly;
+  MutableSpan edges = mesh->edges_for_write();
+  MutableSpan loops = mesh->loops_for_write();
+  const Span polys = mesh->polys();
 
-  BLI_bitmap *edges_used = BLI_BITMAP_NEW(num_edges, __func__);
+  BitVector<> edges_used(num_edges, false);
   EdgeHash *edges_hash = BLI_edgehash_new_ex(__func__, num_edges);
 
-  const MPoly *mp = mpoly;
+  const MPoly *mp = polys.data();
   for (int poly_idx = 0; poly_idx < num_polys; poly_idx++, mp++) {
-    MLoop *ml_prev = &mloop[mp->loopstart + mp->totloop - 1];
-    MLoop *ml = &mloop[mp->loopstart];
+    MLoop *ml_prev = &loops[mp->loopstart + mp->totloop - 1];
+    MLoop *ml = &loops[mp->loopstart];
     for (int loop_idx = 0; loop_idx < mp->totloop; loop_idx++, ml++) {
       void **eval;
       if (!BLI_edgehash_ensure_p(edges_hash, ml_prev->v, ml->v, &eval)) {
         const int edge_idx = ml_prev->e;
 
         /* That edge has not been encountered yet, define it. */
-        if (BLI_BITMAP_TEST(edges_used, edge_idx)) {
+        if (edges_used[edge_idx]) {
           /* Original edge has already been used, we need to define a new one. */
           const int new_edge_idx = num_edges++;
           *eval = POINTER_FROM_INT(new_edge_idx);
@@ -2044,10 +1991,10 @@ static int split_faces_prepare_new_edges(const Mesh *mesh,
         }
         else {
           /* We can re-use original edge. */
-          medge[edge_idx].v1 = ml_prev->v;
-          medge[edge_idx].v2 = ml->v;
+          edges[edge_idx].v1 = ml_prev->v;
+          edges[edge_idx].v2 = ml->v;
           *eval = POINTER_FROM_INT(edge_idx);
-          BLI_BITMAP_ENABLE(edges_used, edge_idx);
+          edges_used[edge_idx].set();
         }
       }
       else {
@@ -2059,7 +2006,6 @@ static int split_faces_prepare_new_edges(const Mesh *mesh,
     }
   }
 
-  MEM_freeN(edges_used);
   BLI_edgehash_free(edges_hash, nullptr);
 
   return num_edges - mesh->totedge;
@@ -2071,7 +2017,6 @@ static void split_faces_split_new_verts(Mesh *mesh,
                                         const int num_new_verts)
 {
   const int verts_len = mesh->totvert - num_new_verts;
-  MVert *mvert = mesh->mvert;
   float(*vert_normals)[3] = BKE_mesh_vertex_normals_for_write(mesh);
 
   /* Normals were already calculated at the beginning of this operation, we rely on that to update
@@ -2079,8 +2024,7 @@ static void split_faces_split_new_verts(Mesh *mesh,
   BLI_assert(!BKE_mesh_vertex_normals_are_dirty(mesh));
 
   /* Remember new_verts is a single linklist, so its items are in reversed order... */
-  MVert *new_mv = &mvert[mesh->totvert - 1];
-  for (int i = mesh->totvert - 1; i >= verts_len; i--, new_mv--, new_verts = new_verts->next) {
+  for (int i = mesh->totvert - 1; i >= verts_len; i--, new_verts = new_verts->next) {
     BLI_assert(new_verts->new_index == i);
     BLI_assert(new_verts->new_index != new_verts->orig_index);
     CustomData_copy_data(&mesh->vdata, &mesh->vdata, new_verts->orig_index, i, 1);
@@ -2096,10 +2040,10 @@ static void split_faces_split_new_edges(Mesh *mesh,
                                         const int num_new_edges)
 {
   const int num_edges = mesh->totedge - num_new_edges;
-  MEdge *medge = mesh->medge;
+  MutableSpan edges = mesh->edges_for_write();
 
   /* Remember new_edges is a single linklist, so its items are in reversed order... */
-  MEdge *new_med = &medge[mesh->totedge - 1];
+  MEdge *new_med = &edges[mesh->totedge - 1];
   for (int i = mesh->totedge - 1; i >= num_edges; i--, new_med--, new_edges = new_edges->next) {
     BLI_assert(new_edges->new_index == i);
     BLI_assert(new_edges->new_index != new_edges->orig_index);
@@ -2127,14 +2071,6 @@ void BKE_mesh_split_faces(Mesh *mesh, bool free_loop_normals)
   SplitFaceNewVert *new_verts = nullptr;
   SplitFaceNewEdge *new_edges = nullptr;
 
-  /* Ensure we own the layers, we need to do this before split_faces_prepare_new_verts as it will
-   * directly assign new indices to existing edges and loops. */
-  CustomData_duplicate_referenced_layers(&mesh->vdata, mesh->totvert);
-  CustomData_duplicate_referenced_layers(&mesh->edata, mesh->totedge);
-  CustomData_duplicate_referenced_layers(&mesh->ldata, mesh->totloop);
-  /* Update pointers in case we duplicated referenced layers. */
-  BKE_mesh_update_customdata_pointers(mesh, false);
-
   /* Detect loop normal spaces (a.k.a. smooth fans) that will need a new vert. */
   const int num_new_verts = split_faces_prepare_new_verts(
       mesh, &lnors_spacearr, &new_verts, memarena);
@@ -2149,14 +2085,12 @@ void BKE_mesh_split_faces(Mesh *mesh, bool free_loop_normals)
     const bool do_edges = (num_new_edges > 0);
 
     /* Reallocate all vert and edge related data. */
+    CustomData_realloc(&mesh->vdata, mesh->totvert, mesh->totvert + num_new_verts);
     mesh->totvert += num_new_verts;
-    CustomData_realloc(&mesh->vdata, mesh->totvert);
     if (do_edges) {
+      CustomData_realloc(&mesh->edata, mesh->totedge, mesh->totedge + num_new_edges);
       mesh->totedge += num_new_edges;
-      CustomData_realloc(&mesh->edata, mesh->totedge);
     }
-    /* Update pointers to a newly allocated memory. */
-    BKE_mesh_update_customdata_pointers(mesh, false);
 
     /* Update normals manually to avoid recalculation after this operation. */
     mesh->runtime.vert_normals = (float(*)[3])MEM_reallocN(mesh->runtime.vert_normals,
diff --git a/source/blender/blenkernel/intern/mesh_boolean_convert.cc b/source/blender/blenkernel/intern/mesh_boolean_convert.cc
index a1ef2d2e6b5..7a04e45fe00 100644
--- a/source/blender/blenkernel/intern/mesh_boolean_convert.cc
+++ b/source/blender/blenkernel/intern/mesh_boolean_convert.cc
@@ -9,6 +9,7 @@
 #include "DNA_meshdata_types.h"
 #include "DNA_object_types.h"
 
+#include "BKE_attribute.hh"
 #include "BKE_customdata.h"
 #include "BKE_material.h"
 #include "BKE_mesh.h"
@@ -23,6 +24,7 @@
 #include "BLI_mesh_intersect.hh"
 #include "BLI_span.hh"
 #include "BLI_task.hh"
+#include "BLI_virtual_array.hh"
 
 namespace blender::meshintersect {
 
@@ -160,9 +162,10 @@ const MPoly *MeshesToIMeshInfo::input_mpoly_for_orig_index(int orig_index,
   int orig_mesh_index = input_mesh_for_imesh_face(orig_index);
   BLI_assert(0 <= orig_mesh_index && orig_mesh_index < meshes.size());
   const Mesh *me = meshes[orig_mesh_index];
+  const Span polys = me->polys();
   int index_in_mesh = orig_index - mesh_poly_offset[orig_mesh_index];
   BLI_assert(0 <= index_in_mesh && index_in_mesh < me->totpoly);
-  const MPoly *mp = &me->mpoly[index_in_mesh];
+  const MPoly *mp = &polys[index_in_mesh];
   if (r_orig_mesh) {
     *r_orig_mesh = me;
   }
@@ -186,9 +189,10 @@ const MVert *MeshesToIMeshInfo::input_mvert_for_orig_index(int orig_index,
   int orig_mesh_index = input_mesh_for_imesh_vert(orig_index);
   BLI_assert(0 <= orig_mesh_index && orig_mesh_index < meshes.size());
   const Mesh *me = meshes[orig_mesh_index];
+  const Span verts = me->verts();
   int index_in_mesh = orig_index - mesh_vert_offset[orig_mesh_index];
   BLI_assert(0 <= index_in_mesh && index_in_mesh < me->totvert);
-  const MVert *mv = &me->mvert[index_in_mesh];
+  const MVert *mv = &verts[index_in_mesh];
   if (r_orig_mesh) {
     *r_orig_mesh = me;
   }
@@ -206,9 +210,10 @@ const MEdge *MeshesToIMeshInfo::input_medge_for_orig_index(int orig_index,
   int orig_mesh_index = input_mesh_for_imesh_edge(orig_index);
   BLI_assert(0 <= orig_mesh_index && orig_mesh_index < meshes.size());
   const Mesh *me = meshes[orig_mesh_index];
+  const Span edges = me->edges();
   int index_in_mesh = orig_index - mesh_edge_offset[orig_mesh_index];
   BLI_assert(0 <= index_in_mesh && index_in_mesh < me->totedge);
-  const MEdge *medge = &me->medge[index_in_mesh];
+  const MEdge *medge = &edges[index_in_mesh];
   if (r_orig_mesh) {
     *r_orig_mesh = me;
   }
@@ -304,17 +309,19 @@ static IMesh meshes_to_imesh(Span meshes,
     bool need_face_flip = r_info->has_negative_transform[mi] != r_info->has_negative_transform[0];
 
     Vector verts(me->totvert);
-    Span mverts = Span(me->mvert, me->totvert);
+    const Span mesh_verts = me->verts();
+    const Span polys = me->polys();
+    const Span loops = me->loops();
 
     /* Allocate verts
      * Skip the matrix multiplication for each point when there is no transform for a mesh,
      * for example when the first mesh is already in the target space. (Note the logic
      * directly above, which uses an identity matrix with a null input transform). */
     if (obmats[mi] == nullptr) {
-      threading::parallel_for(mverts.index_range(), 2048, [&](IndexRange range) {
+      threading::parallel_for(mesh_verts.index_range(), 2048, [&](IndexRange range) {
         float3 co;
         for (int i : range) {
-          co = float3(mverts[i].co);
+          co = float3(mesh_verts[i].co);
           mpq3 mco = mpq3(co.x, co.y, co.z);
           double3 dco(mco[0].get_d(), mco[1].get_d(), mco[2].get_d());
           verts[i] = new Vert(mco, dco, NO_INDEX, i);
@@ -322,26 +329,26 @@ static IMesh meshes_to_imesh(Span meshes,
       });
     }
     else {
-      threading::parallel_for(mverts.index_range(), 2048, [&](IndexRange range) {
+      threading::parallel_for(mesh_verts.index_range(), 2048, [&](IndexRange range) {
         float3 co;
         for (int i : range) {
-          co = r_info->to_target_transform[mi] * float3(mverts[i].co);
+          co = r_info->to_target_transform[mi] * float3(mesh_verts[i].co);
           mpq3 mco = mpq3(co.x, co.y, co.z);
           double3 dco(mco[0].get_d(), mco[1].get_d(), mco[2].get_d());
           verts[i] = new Vert(mco, dco, NO_INDEX, i);
         }
       });
     }
-    for (int i : mverts.index_range()) {
+    for (int i : mesh_verts.index_range()) {
       r_info->mesh_to_imesh_vert[v] = arena.add_or_find_vert(verts[i]);
       ++v;
     }
 
-    for (const MPoly &poly : Span(me->mpoly, me->totpoly)) {
+    for (const MPoly &poly : polys) {
       int flen = poly.totloop;
       face_vert.resize(flen);
       face_edge_orig.resize(flen);
-      const MLoop *l = &me->mloop[poly.loopstart];
+      const MLoop *l = &loops[poly.loopstart];
       for (int i = 0; i < flen; ++i) {
         int mverti = r_info->mesh_vert_offset[mi] + l->v;
         const Vert *fv = r_info->mesh_to_imesh_vert[mverti];
@@ -374,7 +381,6 @@ static void copy_vert_attributes(Mesh *dest_mesh,
                                  int mv_index,
                                  int index_in_orig_me)
 {
-  mv->bweight = orig_mv->bweight;
   mv->flag = orig_mv->flag;
 
   /* For all layers in the orig mesh, copy the layer information. */
@@ -405,13 +411,17 @@ static void copy_poly_attributes(Mesh *dest_mesh,
                                  const Mesh *orig_me,
                                  int mp_index,
                                  int index_in_orig_me,
-                                 Span material_remap)
+                                 Span material_remap,
+                                 MutableSpan dst_material_indices)
 {
-  if (material_remap.size() > 0 && material_remap.index_range().contains(orig_mp->mat_nr)) {
-    mp->mat_nr = material_remap[orig_mp->mat_nr];
+  const VArray src_material_indices = orig_me->attributes().lookup_or_default(
+      "material_index", ATTR_DOMAIN_FACE, 0);
+  const int src_index = src_material_indices[index_in_orig_me];
+  if (material_remap.size() > 0 && material_remap.index_range().contains(src_index)) {
+    dst_material_indices[mp_index] = material_remap[src_index];
   }
   else {
-    mp->mat_nr = orig_mp->mat_nr;
+    dst_material_indices[mp_index] = src_index;
   }
 
   mp->flag = orig_mp->flag;
@@ -439,7 +449,6 @@ static void copy_edge_attributes(Mesh *dest_mesh,
                                  int medge_index,
                                  int index_in_orig_me)
 {
-  medge->bweight = orig_medge->bweight;
   medge->crease = orig_medge->crease;
   medge->flag = orig_medge->flag;
   CustomData *target_cd = &dest_mesh->edata;
@@ -473,14 +482,16 @@ static int fill_orig_loops(const Face *f,
                            const Mesh *orig_me,
                            int orig_me_index,
                            MeshesToIMeshInfo &mim,
-                           Array &orig_loops)
+                           MutableSpan r_orig_loops)
 {
-  orig_loops.fill(-1);
+  r_orig_loops.fill(-1);
+  const Span orig_loops = orig_me->loops();
+
   int orig_mplen = orig_mp->totloop;
   if (f->size() != orig_mplen) {
     return 0;
   }
-  BLI_assert(orig_loops.size() == orig_mplen);
+  BLI_assert(r_orig_loops.size() == orig_mplen);
   /* We'll look for the case where the first vertex in f has an original vertex
    * that is the same as one in orig_me (after correcting for offset in mim meshes).
    * Then see that loop and any subsequent ones have the same start and end vertex.
@@ -502,7 +513,7 @@ static int fill_orig_loops(const Face *f,
   int offset = -1;
   for (int i = 0; i < orig_mplen; ++i) {
     int loop_i = i + orig_mp->loopstart;
-    if (orig_me->mloop[loop_i].v == first_orig_v_in_orig_me) {
+    if (orig_loops[loop_i].v == first_orig_v_in_orig_me) {
       offset = i;
       break;
     }
@@ -513,7 +524,7 @@ static int fill_orig_loops(const Face *f,
   int num_orig_loops_found = 0;
   for (int mp_loop_index = 0; mp_loop_index < orig_mplen; ++mp_loop_index) {
     int orig_mp_loop_index = (mp_loop_index + offset) % orig_mplen;
-    MLoop *l = &orig_me->mloop[orig_mp->loopstart + orig_mp_loop_index];
+    const MLoop *l = &orig_loops[orig_mp->loopstart + orig_mp_loop_index];
     int fv_orig = f->vert[mp_loop_index]->orig;
     if (fv_orig != NO_INDEX) {
       fv_orig -= orig_me_vert_offset;
@@ -522,7 +533,8 @@ static int fill_orig_loops(const Face *f,
       }
     }
     if (l->v == fv_orig) {
-      MLoop *lnext = &orig_me->mloop[orig_mp->loopstart + ((orig_mp_loop_index + 1) % orig_mplen)];
+      const MLoop *lnext =
+          &orig_loops[orig_mp->loopstart + ((orig_mp_loop_index + 1) % orig_mplen)];
       int fvnext_orig = f->vert[(mp_loop_index + 1) % orig_mplen]->orig;
       if (fvnext_orig != NO_INDEX) {
         fvnext_orig -= orig_me_vert_offset;
@@ -531,7 +543,7 @@ static int fill_orig_loops(const Face *f,
         }
       }
       if (lnext->v == fvnext_orig) {
-        orig_loops[mp_loop_index] = orig_mp->loopstart + orig_mp_loop_index;
+        r_orig_loops[mp_loop_index] = orig_mp->loopstart + orig_mp_loop_index;
         ++num_orig_loops_found;
       }
     }
@@ -549,19 +561,18 @@ static void get_poly2d_cos(const Mesh *me,
                            const float4x4 &trans_mat,
                            float r_axis_mat[3][3])
 {
-  int n = mp->totloop;
+  const Span verts = me->verts();
+  const Span loops = me->loops();
+  const Span poly_loops = loops.slice(mp->loopstart, mp->totloop);
 
   /* Project coordinates to 2d in cos_2d, using normal as projection axis. */
   float axis_dominant[3];
-  BKE_mesh_calc_poly_normal(mp, &me->mloop[mp->loopstart], me->mvert, axis_dominant);
+  BKE_mesh_calc_poly_normal(mp, &loops[mp->loopstart], verts.data(), axis_dominant);
   axis_dominant_v3_to_m3(r_axis_mat, axis_dominant);
-  MLoop *ml = &me->mloop[mp->loopstart];
-  const MVert *mverts = me->mvert;
-  for (int i = 0; i < n; ++i) {
-    float3 co = mverts[ml->v].co;
+  for (const int i : poly_loops.index_range()) {
+    float3 co = verts[poly_loops[i].v].co;
     co = trans_mat * co;
     mul_v2_m3v3(cos_2d[i], r_axis_mat, co);
-    ++ml;
   }
 }
 
@@ -596,6 +607,8 @@ static void copy_or_interp_loop_attributes(Mesh *dest_mesh,
     get_poly2d_cos(orig_me, orig_mp, cos_2d, mim.to_target_transform[orig_me_index], axis_mat);
   }
   CustomData *target_cd = &dest_mesh->ldata;
+  const Span dst_verts = dest_mesh->verts();
+  const Span dst_loops = dest_mesh->loops();
   for (int i = 0; i < mp->totloop; ++i) {
     int loop_index = mp->loopstart + i;
     int orig_loop_index = norig > 0 ? orig_loops[i] : -1;
@@ -605,7 +618,7 @@ static void copy_or_interp_loop_attributes(Mesh *dest_mesh,
        * The coordinate needs to be projected into 2d,  just like the interpolating polygon's
        * coordinates were. The `dest_mesh` coordinates are already in object 0 local space. */
       float co[2];
-      mul_v2_m3v3(co, axis_mat, dest_mesh->mvert[dest_mesh->mloop[loop_index].v].co);
+      mul_v2_m3v3(co, axis_mat, dst_verts[dst_loops[loop_index].v].co);
       interp_weights_poly_v2(weights.data(), cos_2d, orig_mp->totloop, co);
     }
     for (int source_layer_i = 0; source_layer_i < source_cd->totlayer; ++source_layer_i) {
@@ -663,15 +676,15 @@ static void merge_vertex_loop_poly_customdata_layers(Mesh *target, MeshesToIMesh
     const Mesh *me = mim.meshes[mesh_index];
     if (me->totvert) {
       CustomData_merge(
-          &me->vdata, &target->vdata, CD_MASK_MESH.vmask, CD_DEFAULT, target->totvert);
+          &me->vdata, &target->vdata, CD_MASK_MESH.vmask, CD_SET_DEFAULT, target->totvert);
     }
     if (me->totloop) {
       CustomData_merge(
-          &me->ldata, &target->ldata, CD_MASK_MESH.lmask, CD_DEFAULT, target->totloop);
+          &me->ldata, &target->ldata, CD_MASK_MESH.lmask, CD_SET_DEFAULT, target->totloop);
     }
     if (me->totpoly) {
       CustomData_merge(
-          &me->pdata, &target->pdata, CD_MASK_MESH.pmask, CD_DEFAULT, target->totpoly);
+          &me->pdata, &target->pdata, CD_MASK_MESH.pmask, CD_SET_DEFAULT, target->totpoly);
     }
   }
 }
@@ -682,7 +695,7 @@ static void merge_edge_customdata_layers(Mesh *target, MeshesToIMeshInfo &mim)
     const Mesh *me = mim.meshes[mesh_index];
     if (me->totedge) {
       CustomData_merge(
-          &me->edata, &target->edata, CD_MASK_MESH.emask, CD_DEFAULT, target->totedge);
+          &me->edata, &target->edata, CD_MASK_MESH.emask, CD_SET_DEFAULT, target->totedge);
     }
   }
 }
@@ -708,9 +721,10 @@ static Mesh *imesh_to_mesh(IMesh *im, MeshesToIMeshInfo &mim)
 
   merge_vertex_loop_poly_customdata_layers(result, mim);
   /* Set the vertex coordinate values and other data. */
+  MutableSpan verts = result->verts_for_write();
   for (int vi : im->vert_index_range()) {
     const Vert *v = im->vert(vi);
-    MVert *mv = &result->mvert[vi];
+    MVert *mv = &verts[vi];
     copy_v3fl_v3db(mv->co, v->co);
     if (v->orig != NO_INDEX) {
       const Mesh *orig_me;
@@ -722,8 +736,13 @@ static Mesh *imesh_to_mesh(IMesh *im, MeshesToIMeshInfo &mim)
 
   /* Set the loopstart and totloop for each output poly,
    * and set the vertices in the appropriate loops. */
+  bke::SpanAttributeWriter dst_material_indices =
+      result->attributes_for_write().lookup_or_add_for_write_only_span("material_index",
+                                                                            ATTR_DOMAIN_FACE);
   int cur_loop_index = 0;
-  MLoop *l = result->mloop;
+  MutableSpan dst_loops = result->loops_for_write();
+  MutableSpan dst_polys = result->polys_for_write();
+  MLoop *l = dst_loops.data();
   for (int fi : im->face_index_range()) {
     const Face *f = im->face(fi);
     const Mesh *orig_me;
@@ -731,7 +750,7 @@ static Mesh *imesh_to_mesh(IMesh *im, MeshesToIMeshInfo &mim)
     int orig_me_index;
     const MPoly *orig_mp = mim.input_mpoly_for_orig_index(
         f->orig, &orig_me, &orig_me_index, &index_in_orig_me);
-    MPoly *mp = &result->mpoly[fi];
+    MPoly *mp = &dst_polys[fi];
     mp->totloop = f->size();
     mp->loopstart = cur_loop_index;
     for (int j : f->index_range()) {
@@ -750,9 +769,11 @@ static Mesh *imesh_to_mesh(IMesh *im, MeshesToIMeshInfo &mim)
                          index_in_orig_me,
                          (mim.material_remaps.size() > 0) ?
                              mim.material_remaps[orig_me_index].as_span() :
-                             Span());
+                             Span(),
+                         dst_material_indices.span);
     copy_or_interp_loop_attributes(result, f, mp, orig_mp, orig_me, orig_me_index, mim);
   }
+  dst_material_indices.finish();
 
   /* BKE_mesh_calc_edges will calculate and populate all the
    * MEdges from the MPolys. */
@@ -761,17 +782,18 @@ static Mesh *imesh_to_mesh(IMesh *im, MeshesToIMeshInfo &mim)
 
   /* Now that the MEdges are populated, we can copy over the required attributes and custom layers.
    */
+  MutableSpan edges = result->edges_for_write();
   for (int fi : im->face_index_range()) {
     const Face *f = im->face(fi);
-    MPoly *mp = &result->mpoly[fi];
+    const MPoly *mp = &dst_polys[fi];
     for (int j : f->index_range()) {
       if (f->edge_orig[j] != NO_INDEX) {
         const Mesh *orig_me;
         int index_in_orig_me;
         const MEdge *orig_medge = mim.input_medge_for_orig_index(
             f->edge_orig[j], &orig_me, &index_in_orig_me);
-        int e_index = result->mloop[mp->loopstart + j].e;
-        MEdge *medge = &result->medge[e_index];
+        int e_index = dst_loops[mp->loopstart + j].e;
+        MEdge *medge = &edges[e_index];
         copy_edge_attributes(result, medge, orig_medge, orig_me, e_index, index_in_orig_me);
       }
     }
@@ -833,12 +855,14 @@ Mesh *direct_mesh_boolean(Span meshes,
 
   /* Store intersecting edge indices. */
   if (r_intersecting_edges != nullptr) {
+    const Span polys = result->polys();
+    const Span loops = result->loops();
     for (int fi : m_out.face_index_range()) {
       const Face &face = *m_out.face(fi);
-      const MPoly &poly = result->mpoly[fi];
+      const MPoly &poly = polys[fi];
       for (int corner_i : face.index_range()) {
         if (face.is_intersect[corner_i]) {
-          int e_index = result->mloop[poly.loopstart + corner_i].e;
+          int e_index = loops[poly.loopstart + corner_i].e;
           r_intersecting_edges->append(e_index);
         }
       }
diff --git a/source/blender/blenkernel/intern/mesh_calc_edges.cc b/source/blender/blenkernel/intern/mesh_calc_edges.cc
index 31e20750cf2..cc315130ad1 100644
--- a/source/blender/blenkernel/intern/mesh_calc_edges.cc
+++ b/source/blender/blenkernel/intern/mesh_calc_edges.cc
@@ -80,9 +80,10 @@ static void add_existing_edges_to_hash_maps(Mesh *mesh,
                                             uint32_t parallel_mask)
 {
   /* Assume existing edges are valid. */
+  const Span edges = mesh->edges();
   threading::parallel_for_each(edge_maps, [&](EdgeMap &edge_map) {
     const int task_index = &edge_map - edge_maps.data();
-    for (const MEdge &edge : Span(mesh->medge, mesh->totedge)) {
+    for (const MEdge &edge : edges) {
       OrderedEdge ordered_edge{edge.v1, edge.v2};
       /* Only add the edge when it belongs into this map. */
       if (task_index == (parallel_mask & ordered_edge.hash2())) {
@@ -96,10 +97,11 @@ static void add_polygon_edges_to_hash_maps(Mesh *mesh,
                                            MutableSpan edge_maps,
                                            uint32_t parallel_mask)
 {
-  const Span loops{mesh->mloop, mesh->totloop};
+  const Span polys = mesh->polys();
+  const Span loops = mesh->loops();
   threading::parallel_for_each(edge_maps, [&](EdgeMap &edge_map) {
     const int task_index = &edge_map - edge_maps.data();
-    for (const MPoly &poly : Span(mesh->mpoly, mesh->totpoly)) {
+    for (const MPoly &poly : polys) {
       Span poly_loops = loops.slice(poly.loopstart, poly.totloop);
       const MLoop *prev_loop = &poly_loops.last();
       for (const MLoop &next_loop : poly_loops) {
@@ -157,10 +159,11 @@ static void update_edge_indices_in_poly_loops(Mesh *mesh,
                                               Span edge_maps,
                                               uint32_t parallel_mask)
 {
-  const MutableSpan loops{mesh->mloop, mesh->totloop};
+  const Span polys = mesh->polys();
+  MutableSpan loops = mesh->loops_for_write();
   threading::parallel_for(IndexRange(mesh->totpoly), 100, [&](IndexRange range) {
     for (const int poly_index : range) {
-      MPoly &poly = mesh->mpoly[poly_index];
+      const MPoly &poly = polys[poly_index];
       MutableSpan poly_loops = loops.slice(poly.loopstart, poly.totloop);
 
       MLoop *prev_loop = &poly_loops.last();
@@ -242,7 +245,6 @@ void BKE_mesh_calc_edges(Mesh *mesh, bool keep_existing_edges, const bool select
   CustomData_reset(&mesh->edata);
   CustomData_add_layer(&mesh->edata, CD_MEDGE, CD_ASSIGN, new_edges.data(), new_totedge);
   mesh->totedge = new_totedge;
-  mesh->medge = new_edges.data();
 
   /* Explicitly clear edge maps, because that way it can be parallelized. */
   clear_hash_tables(edge_maps);
diff --git a/source/blender/blenkernel/intern/mesh_convert.cc b/source/blender/blenkernel/intern/mesh_convert.cc
index 7ebb3e25fd4..e56df0e3fe3 100644
--- a/source/blender/blenkernel/intern/mesh_convert.cc
+++ b/source/blender/blenkernel/intern/mesh_convert.cc
@@ -22,6 +22,7 @@
 #include "BLI_index_range.hh"
 #include "BLI_listbase.h"
 #include "BLI_math.h"
+#include "BLI_span.hh"
 #include "BLI_string.h"
 #include "BLI_utildefines.h"
 
@@ -53,7 +54,11 @@
 #include "DEG_depsgraph.h"
 #include "DEG_depsgraph_query.h"
 
+using blender::float3;
 using blender::IndexRange;
+using blender::MutableSpan;
+using blender::Span;
+using blender::StringRefNull;
 
 /* Define for cases when you want extra validation of mesh
  * after certain modifications.
@@ -69,121 +74,58 @@ using blender::IndexRange;
 
 static CLG_LogRef LOG = {"bke.mesh_convert"};
 
-void BKE_mesh_from_metaball(ListBase *lb, Mesh *me)
-{
-  DispList *dl;
-  MVert *mvert;
-  MLoop *mloop, *allloop;
-  MPoly *mpoly;
-  int a, *index;
-
-  dl = (DispList *)lb->first;
-  if (dl == nullptr) {
-    return;
-  }
-
-  if (dl->type == DL_INDEX4) {
-    mvert = (MVert *)CustomData_add_layer(&me->vdata, CD_MVERT, CD_CALLOC, nullptr, dl->nr);
-    allloop = mloop = (MLoop *)CustomData_add_layer(
-        &me->ldata, CD_MLOOP, CD_CALLOC, nullptr, dl->parts * 4);
-    mpoly = (MPoly *)CustomData_add_layer(&me->pdata, CD_MPOLY, CD_CALLOC, nullptr, dl->parts);
-    me->mvert = mvert;
-    me->mloop = mloop;
-    me->mpoly = mpoly;
-    me->totvert = dl->nr;
-    me->totpoly = dl->parts;
-
-    for (const int i : IndexRange(dl->nr)) {
-      copy_v3_v3(me->mvert[i].co, &dl->verts[3 * i]);
-    }
-
-    a = dl->parts;
-    index = dl->index;
-    while (a--) {
-      int count = index[2] != index[3] ? 4 : 3;
-
-      mloop[0].v = index[0];
-      mloop[1].v = index[1];
-      mloop[2].v = index[2];
-      if (count == 4) {
-        mloop[3].v = index[3];
-      }
-
-      mpoly->totloop = count;
-      mpoly->loopstart = (int)(mloop - allloop);
-      mpoly->flag = ME_SMOOTH;
-
-      mpoly++;
-      mloop += count;
-      me->totloop += count;
-      index += 4;
-    }
-
-    BKE_mesh_update_customdata_pointers(me, true);
-    BKE_mesh_calc_edges(me, true, false);
-  }
-}
-
 /**
  * Specialized function to use when we _know_ existing edges don't overlap with poly edges.
  */
-static void make_edges_mdata_extend(
-    MEdge **r_alledge, int *r_totedge, const MPoly *mpoly, MLoop *mloop, const int totpoly)
+static void make_edges_mdata_extend(Mesh &mesh)
 {
-  int totedge = *r_totedge;
-  int totedge_new;
-  EdgeHash *eh;
-  uint eh_reserve;
+  int totedge = mesh.totedge;
   const MPoly *mp;
   int i;
 
-  eh_reserve = max_ii(totedge, BLI_EDGEHASH_SIZE_GUESS_FROM_POLYS(totpoly));
-  eh = BLI_edgehash_new_ex(__func__, eh_reserve);
+  const Span polys = mesh.polys();
+  MutableSpan loops = mesh.loops_for_write();
 
-  for (i = 0, mp = mpoly; i < totpoly; i++, mp++) {
-    BKE_mesh_poly_edgehash_insert(eh, mp, mloop + mp->loopstart);
+  const int eh_reserve = max_ii(totedge, BLI_EDGEHASH_SIZE_GUESS_FROM_POLYS(mesh.totpoly));
+  EdgeHash *eh = BLI_edgehash_new_ex(__func__, eh_reserve);
+
+  for (const MPoly &poly : polys) {
+    BKE_mesh_poly_edgehash_insert(eh, &poly, &loops[poly.loopstart]);
   }
 
-  totedge_new = BLI_edgehash_len(eh);
+  const int totedge_new = BLI_edgehash_len(eh);
 
 #ifdef DEBUG
   /* ensure that there's no overlap! */
   if (totedge_new) {
-    MEdge *medge = *r_alledge;
-    for (i = 0; i < totedge; i++, medge++) {
-      BLI_assert(BLI_edgehash_haskey(eh, medge->v1, medge->v2) == false);
+    for (const MEdge &edge : mesh.edges()) {
+      BLI_assert(BLI_edgehash_haskey(eh, edge.v1, edge.v2) == false);
     }
   }
 #endif
 
   if (totedge_new) {
+    /* The only layer should be edges, so no other layers need to be initialized. */
+    BLI_assert(mesh.edata.totlayer == 1);
+    CustomData_realloc(&mesh.edata, totedge, totedge + totedge_new);
+    mesh.totedge += totedge_new;
+    MutableSpan edges = mesh.edges_for_write();
+    MEdge *medge = &edges[totedge];
+
     EdgeHashIterator *ehi;
-    MEdge *medge;
     uint e_index = totedge;
-
-    *r_alledge = medge = (MEdge *)(*r_alledge ?
-                                       MEM_reallocN(*r_alledge,
-                                                    sizeof(MEdge) * (totedge + totedge_new)) :
-                                       MEM_calloc_arrayN(totedge_new, sizeof(MEdge), __func__));
-    medge += totedge;
-
-    totedge += totedge_new;
-
-    /* --- */
     for (ehi = BLI_edgehashIterator_new(eh); BLI_edgehashIterator_isDone(ehi) == false;
          BLI_edgehashIterator_step(ehi), ++medge, e_index++) {
       BLI_edgehashIterator_getKey(ehi, &medge->v1, &medge->v2);
       BLI_edgehashIterator_setValue(ehi, POINTER_FROM_UINT(e_index));
 
-      medge->crease = medge->bweight = 0;
+      medge->crease = 0;
       medge->flag = ME_EDGEDRAW | ME_EDGERENDER;
     }
     BLI_edgehashIterator_free(ehi);
 
-    *r_totedge = totedge;
-
-    for (i = 0, mp = mpoly; i < totpoly; i++, mp++) {
-      MLoop *l = &mloop[mp->loopstart];
+    for (i = 0, mp = polys.data(); i < mesh.totpoly; i++, mp++) {
+      MLoop *l = &loops[mp->loopstart];
       MLoop *l_prev = (l + (mp->totloop - 1));
       int j;
       for (j = 0; j < mp->totloop; j++, l++) {
@@ -197,25 +139,9 @@ static void make_edges_mdata_extend(
   BLI_edgehash_free(eh, nullptr);
 }
 
-/* Initialize mverts, medges and, faces for converting nurbs to mesh and derived mesh */
-/* use specified dispbase */
-static int mesh_nurbs_displist_to_mdata(const Curve *cu,
-                                        const ListBase *dispbase,
-                                        MVert **r_allvert,
-                                        int *r_totvert,
-                                        MEdge **r_alledge,
-                                        int *r_totedge,
-                                        MLoop **r_allloop,
-                                        MPoly **r_allpoly,
-                                        MLoopUV **r_alluv,
-                                        int *r_totloop,
-                                        int *r_totpoly)
+static Mesh *mesh_nurbs_displist_to_mesh(const Curve *cu, const ListBase *dispbase)
 {
-  MVert *mvert;
-  MPoly *mpoly;
-  MLoop *mloop;
-  MLoopUV *mloopuv = nullptr;
-  MEdge *medge;
+  using namespace blender::bke;
   const float *data;
   int a, b, ofs, vertcount, startvert, totvert = 0, totedge = 0, totloop = 0, totpoly = 0;
   int p1, p2, p3, p4, *index;
@@ -257,21 +183,24 @@ static int mesh_nurbs_displist_to_mdata(const Curve *cu,
   }
 
   if (totvert == 0) {
-    /* Make Sure you check ob->data is a curve. */
-    // error("can't convert");
-    return -1;
+    return BKE_mesh_new_nomain(0, 0, 0, 0, 0);
   }
 
-  *r_allvert = mvert = (MVert *)MEM_calloc_arrayN(totvert, sizeof(MVert), "nurbs_init mvert");
-  *r_alledge = medge = (MEdge *)MEM_calloc_arrayN(totedge, sizeof(MEdge), "nurbs_init medge");
-  *r_allloop = mloop = (MLoop *)MEM_calloc_arrayN(
-      totpoly, sizeof(MLoop[4]), "nurbs_init mloop"); /* totloop */
-  *r_allpoly = mpoly = (MPoly *)MEM_calloc_arrayN(totpoly, sizeof(MPoly), "nurbs_init mloop");
+  Mesh *mesh = BKE_mesh_new_nomain(totvert, totedge, 0, totloop, totpoly);
+  MutableSpan verts = mesh->verts_for_write();
+  MutableSpan edges = mesh->edges_for_write();
+  MutableSpan polys = mesh->polys_for_write();
+  MutableSpan loops = mesh->loops_for_write();
 
-  if (r_alluv) {
-    *r_alluv = mloopuv = (MLoopUV *)MEM_calloc_arrayN(
-        totpoly, sizeof(MLoopUV[4]), "nurbs_init mloopuv");
-  }
+  MVert *mvert = verts.data();
+  MEdge *medge = edges.data();
+  MPoly *mpoly = polys.data();
+  MLoop *mloop = loops.data();
+  MutableAttributeAccessor attributes = mesh->attributes_for_write();
+  SpanAttributeWriter material_indices = attributes.lookup_or_add_for_write_only_span(
+      "material_index", ATTR_DOMAIN_FACE);
+  MLoopUV *mloopuv = static_cast(CustomData_add_layer_named(
+      &mesh->ldata, CD_MLOOPUV, CD_SET_DEFAULT, nullptr, mesh->totloop, "UVMap"));
 
   /* verts and faces */
   vertcount = 0;
@@ -346,9 +275,9 @@ static int mesh_nurbs_displist_to_mdata(const Curve *cu,
         mloop[0].v = startvert + index[0];
         mloop[1].v = startvert + index[2];
         mloop[2].v = startvert + index[1];
-        mpoly->loopstart = (int)(mloop - (*r_allloop));
+        mpoly->loopstart = (int)(mloop - loops.data());
         mpoly->totloop = 3;
-        mpoly->mat_nr = dl->col;
+        material_indices.span[mpoly - polys.data()] = dl->col;
 
         if (mloopuv) {
           for (int i = 0; i < 3; i++, mloopuv++) {
@@ -406,9 +335,9 @@ static int mesh_nurbs_displist_to_mdata(const Curve *cu,
           mloop[1].v = p3;
           mloop[2].v = p4;
           mloop[3].v = p2;
-          mpoly->loopstart = (int)(mloop - (*r_allloop));
+          mpoly->loopstart = (int)(mloop - loops.data());
           mpoly->totloop = 4;
-          mpoly->mat_nr = dl->col;
+          material_indices.span[mpoly - polys.data()] = dl->col;
 
           if (mloopuv) {
             int orco_sizeu = dl->nr - 1;
@@ -458,15 +387,12 @@ static int mesh_nurbs_displist_to_mdata(const Curve *cu,
   }
 
   if (totpoly) {
-    make_edges_mdata_extend(r_alledge, &totedge, *r_allpoly, *r_allloop, totpoly);
+    make_edges_mdata_extend(*mesh);
   }
 
-  *r_totpoly = totpoly;
-  *r_totloop = totloop;
-  *r_totedge = totedge;
-  *r_totvert = totvert;
+  material_indices.finish();
 
-  return 0;
+  return mesh;
 }
 
 /**
@@ -487,60 +413,12 @@ static void mesh_copy_texture_space_from_curve_type(const Curve *cu, Mesh *me)
 Mesh *BKE_mesh_new_nomain_from_curve_displist(const Object *ob, const ListBase *dispbase)
 {
   const Curve *cu = (const Curve *)ob->data;
-  Mesh *mesh;
-  MVert *allvert;
-  MEdge *alledge;
-  MLoop *allloop;
-  MPoly *allpoly;
-  MLoopUV *alluv = nullptr;
-  int totvert, totedge, totloop, totpoly;
-
-  if (mesh_nurbs_displist_to_mdata(cu,
-                                   dispbase,
-                                   &allvert,
-                                   &totvert,
-                                   &alledge,
-                                   &totedge,
-                                   &allloop,
-                                   &allpoly,
-                                   &alluv,
-                                   &totloop,
-                                   &totpoly) != 0) {
-    /* Error initializing mdata. This often happens when curve is empty */
-    return BKE_mesh_new_nomain(0, 0, 0, 0, 0);
-  }
-
-  mesh = BKE_mesh_new_nomain(totvert, totedge, 0, totloop, totpoly);
-
-  if (totvert != 0) {
-    memcpy(mesh->mvert, allvert, totvert * sizeof(MVert));
-  }
-  if (totedge != 0) {
-    memcpy(mesh->medge, alledge, totedge * sizeof(MEdge));
-  }
-  if (totloop != 0) {
-    memcpy(mesh->mloop, allloop, totloop * sizeof(MLoop));
-  }
-  if (totpoly != 0) {
-    memcpy(mesh->mpoly, allpoly, totpoly * sizeof(MPoly));
-  }
-
-  if (alluv) {
-    const char *uvname = "UVMap";
-    CustomData_add_layer_named(&mesh->ldata, CD_MLOOPUV, CD_ASSIGN, alluv, totloop, uvname);
-  }
 
+  Mesh *mesh = mesh_nurbs_displist_to_mesh(cu, dispbase);
   mesh_copy_texture_space_from_curve_type(cu, mesh);
-
-  /* Copy curve materials. */
   mesh->mat = (Material **)MEM_dupallocN(cu->mat);
   mesh->totcol = cu->totcol;
 
-  MEM_freeN(allvert);
-  MEM_freeN(alledge);
-  MEM_freeN(allloop);
-  MEM_freeN(allpoly);
-
   return mesh;
 }
 
@@ -557,7 +435,7 @@ Mesh *BKE_mesh_new_nomain_from_curve(const Object *ob)
 
 struct EdgeLink {
   struct EdgeLink *next, *prev;
-  void *edge;
+  const void *edge;
 };
 
 struct VertLink {
@@ -581,10 +459,13 @@ static void appendPolyLineVert(ListBase *lb, uint index)
 
 void BKE_mesh_to_curve_nurblist(const Mesh *me, ListBase *nurblist, const int edge_users_test)
 {
-  MVert *mvert = me->mvert;
-  MEdge *med, *medge = me->medge;
-  MPoly *mp, *mpoly = me->mpoly;
-  MLoop *mloop = me->mloop;
+  const Span verts = me->verts();
+  const Span mesh_edges = me->edges();
+  const Span polys = me->polys();
+  const Span loops = me->loops();
+
+  const MEdge *med;
+  const MPoly *mp;
 
   int medge_len = me->totedge;
   int mpoly_len = me->totpoly;
@@ -598,8 +479,8 @@ void BKE_mesh_to_curve_nurblist(const Mesh *me, ListBase *nurblist, const int ed
 
   /* get boundary edges */
   edge_users = (int *)MEM_calloc_arrayN(medge_len, sizeof(int), __func__);
-  for (i = 0, mp = mpoly; i < mpoly_len; i++, mp++) {
-    MLoop *ml = &mloop[mp->loopstart];
+  for (i = 0, mp = polys.data(); i < mpoly_len; i++, mp++) {
+    const MLoop *ml = &loops[mp->loopstart];
     int j;
     for (j = 0; j < mp->totloop; j++, ml++) {
       edge_users[ml->e]++;
@@ -607,7 +488,7 @@ void BKE_mesh_to_curve_nurblist(const Mesh *me, ListBase *nurblist, const int ed
   }
 
   /* create edges from all faces (so as to find edges not in any faces) */
-  med = medge;
+  med = mesh_edges.data();
   for (i = 0; i < medge_len; i++, med++) {
     if (edge_users[i] == edge_users_test) {
       EdgeLink *edl = MEM_cnew("EdgeLink");
@@ -710,7 +591,7 @@ void BKE_mesh_to_curve_nurblist(const Mesh *me, ListBase *nurblist, const int ed
         /* add points */
         vl = (VertLink *)polyline.first;
         for (i = 0, bp = nu->bp; i < totpoly; i++, bp++, vl = (VertLink *)vl->next) {
-          copy_v3_v3(bp->vec, mvert[vl->index].co);
+          copy_v3_v3(bp->vec, verts[vl->index].co);
           bp->f1 = SELECT;
           bp->radius = bp->weight = 1.0;
         }
@@ -751,21 +632,27 @@ void BKE_mesh_to_curve(Main *bmain, Depsgraph *depsgraph, Scene *UNUSED(scene),
 
 void BKE_pointcloud_from_mesh(Mesh *me, PointCloud *pointcloud)
 {
-  BLI_assert(me != nullptr);
+  using namespace blender;
 
+  BLI_assert(me != nullptr);
+  /* The pointcloud should only contain the position attribute, otherwise more attributes would
+   * need to be initialized below. */
+  BLI_assert(pointcloud->attributes().all_ids().size() == 1);
+  CustomData_realloc(&pointcloud->pdata, pointcloud->totpoint, me->totvert);
   pointcloud->totpoint = me->totvert;
-  CustomData_realloc(&pointcloud->pdata, pointcloud->totpoint);
 
   /* Copy over all attributes. */
   CustomData_merge(&me->vdata, &pointcloud->pdata, CD_MASK_PROP_ALL, CD_DUPLICATE, me->totvert);
-  BKE_pointcloud_update_customdata_pointers(pointcloud);
-  CustomData_update_typemap(&pointcloud->pdata);
 
-  MVert *mvert;
-  mvert = me->mvert;
-  for (int i = 0; i < me->totvert; i++, mvert++) {
-    copy_v3_v3(pointcloud->co[i], mvert->co);
-  }
+  bke::AttributeAccessor mesh_attributes = me->attributes();
+  bke::MutableAttributeAccessor point_attributes = pointcloud->attributes_for_write();
+
+  const VArray mesh_positions = mesh_attributes.lookup_or_default(
+      "position", ATTR_DOMAIN_POINT, float3(0));
+  bke::SpanAttributeWriter point_positions =
+      point_attributes.lookup_or_add_for_write_only_span("position", ATTR_DOMAIN_POINT);
+  mesh_positions.materialize(point_positions.span);
+  point_positions.finish();
 }
 
 void BKE_mesh_to_pointcloud(Main *bmain, Depsgraph *depsgraph, Scene *UNUSED(scene), Object *ob)
@@ -800,18 +687,16 @@ void BKE_mesh_from_pointcloud(const PointCloud *pointcloud, Mesh *me)
       &pointcloud->pdata, &me->vdata, CD_MASK_PROP_ALL, CD_DUPLICATE, pointcloud->totpoint);
 
   /* Convert the Position attribute to a mesh vertex. */
-  me->mvert = (MVert *)CustomData_add_layer(&me->vdata, CD_MVERT, CD_CALLOC, nullptr, me->totvert);
-  CustomData_update_typemap(&me->vdata);
+  CustomData_add_layer(&me->vdata, CD_MVERT, CD_SET_DEFAULT, nullptr, me->totvert);
 
   const int layer_idx = CustomData_get_named_layer_index(
       &me->vdata, CD_PROP_FLOAT3, POINTCLOUD_ATTR_POSITION);
   CustomDataLayer *pos_layer = &me->vdata.layers[layer_idx];
   float(*positions)[3] = (float(*)[3])pos_layer->data;
 
-  MVert *mvert;
-  mvert = me->mvert;
-  for (int i = 0; i < me->totvert; i++, mvert++) {
-    copy_v3_v3(mvert->co, positions[i]);
+  MutableSpan verts = me->verts_for_write();
+  for (int i = 0; i < me->totvert; i++) {
+    copy_v3_v3(verts[i].co, positions[i]);
   }
 
   /* Delete Position attribute since it is now in vertex coordinates. */
@@ -820,9 +705,9 @@ void BKE_mesh_from_pointcloud(const PointCloud *pointcloud, Mesh *me)
 
 void BKE_mesh_edges_set_draw_render(Mesh *mesh)
 {
-  MEdge *med = mesh->medge;
-  for (int i = 0; i < mesh->totedge; i++, med++) {
-    med->flag |= ME_EDGEDRAW | ME_EDGERENDER;
+  MutableSpan edges = mesh->edges_for_write();
+  for (int i = 0; i < mesh->totedge; i++) {
+    edges[i].flag |= ME_EDGEDRAW | ME_EDGERENDER;
   }
 }
 
@@ -980,6 +865,12 @@ static Mesh *mesh_new_from_curve_type_object(const Object *object)
 
   /* If evaluating the curve replaced object data with different data, free the original data. */
   if (temp_data != temp_object->data) {
+    if (GS(temp_data->name) == ID_CU_LEGACY) {
+      /* Clear edit mode pointers that were explicitly copied to the temporary curve. */
+      Curve *curve = reinterpret_cast(temp_data);
+      curve->editfont = nullptr;
+      curve->editnurb = nullptr;
+    }
     BKE_id_free(nullptr, temp_data);
   }
 
@@ -992,32 +883,21 @@ static Mesh *mesh_new_from_curve_type_object(const Object *object)
 
 static Mesh *mesh_new_from_mball_object(Object *object)
 {
-  MetaBall *mball = (MetaBall *)object->data;
-
   /* NOTE: We can only create mesh for a polygonized meta ball. This figures out all original meta
    * balls and all evaluated child meta balls (since polygonization is only stored in the mother
    * ball).
    *
    * Create empty mesh so script-authors don't run into None objects. */
-  if (!DEG_is_evaluated_object(object) || object->runtime.curve_cache == nullptr ||
-      BLI_listbase_is_empty(&object->runtime.curve_cache->disp)) {
+  if (!DEG_is_evaluated_object(object)) {
     return (Mesh *)BKE_id_new_nomain(ID_ME, ((ID *)object->data)->name + 2);
   }
 
-  Mesh *mesh_result = (Mesh *)BKE_id_new_nomain(ID_ME, ((ID *)object->data)->name + 2);
-  BKE_mesh_from_metaball(&object->runtime.curve_cache->disp, mesh_result);
-  BKE_mesh_texspace_copy_from_object(mesh_result, object);
-
-  /* Copy materials. */
-  mesh_result->totcol = mball->totcol;
-  mesh_result->mat = (Material **)MEM_dupallocN(mball->mat);
-  if (mball->mat != nullptr) {
-    for (int i = mball->totcol; i-- > 0;) {
-      mesh_result->mat[i] = BKE_object_material_get(object, i + 1);
-    }
+  const Mesh *mesh_eval = BKE_object_get_evaluated_mesh(object);
+  if (mesh_eval == nullptr) {
+    return (Mesh *)BKE_id_new_nomain(ID_ME, ((ID *)object->data)->name + 2);
   }
 
-  return mesh_result;
+  return BKE_mesh_copy_for_eval(mesh_eval, false);
 }
 
 static Mesh *mesh_new_from_mesh(Object *object, Mesh *mesh)
@@ -1206,10 +1086,10 @@ Mesh *BKE_mesh_new_from_object_to_bmain(Main *bmain,
   mesh_in_bmain->smoothresh = mesh->smoothresh;
   mesh->mat = nullptr;
 
-  BKE_mesh_nomain_to_mesh(mesh, mesh_in_bmain, nullptr, &CD_MASK_MESH, true);
+  BKE_mesh_nomain_to_mesh(mesh, mesh_in_bmain, nullptr);
 
   /* Anonymous attributes shouldn't exist on original data. */
-  blender::bke::mesh_attributes_for_write(*mesh_in_bmain).remove_anonymous();
+  mesh_in_bmain->attributes_for_write().remove_anonymous();
 
   /* User-count is required because so far mesh was in a limbo, where library management does
    * not perform any user management (i.e. copy of a mesh will not increase users of materials). */
@@ -1293,7 +1173,8 @@ Mesh *BKE_mesh_create_derived_for_modifier(struct Depsgraph *depsgraph,
 
   if (build_shapekey_layers && me->key &&
       (kb = (KeyBlock *)BLI_findlink(&me->key->block, ob_eval->shapenr - 1))) {
-    BKE_keyblock_convert_to_mesh(kb, me->mvert, me->totvert);
+    MutableSpan verts = me->verts_for_write();
+    BKE_keyblock_convert_to_mesh(kb, verts.data(), me->totvert);
   }
 
   Mesh *mesh_temp = (Mesh *)BKE_id_copy_ex(nullptr, &me->id, nullptr, LIB_ID_COPY_LOCALIZE);
@@ -1359,242 +1240,113 @@ Mesh *BKE_mesh_create_derived_for_modifier(struct Depsgraph *depsgraph,
   return result;
 }
 
-/* This is a Mesh-based copy of the same function in DerivedMesh.cc */
-static void shapekey_layers_to_keyblocks(Mesh *mesh_src, Mesh *mesh_dst, int actshape_uid)
+static KeyBlock *keyblock_ensure_from_uid(Key &key, const int uid, const StringRefNull name)
 {
-  KeyBlock *kb;
-  int i, j, tot;
-
-  if (!mesh_dst->key) {
-    return;
+  if (KeyBlock *kb = BKE_keyblock_find_uid(&key, uid)) {
+    return kb;
   }
+  KeyBlock *kb = BKE_keyblock_add(&key, name.c_str());
+  kb->uid = uid;
+  return kb;
+}
 
-  tot = CustomData_number_of_layers(&mesh_src->vdata, CD_SHAPEKEY);
-  for (i = 0; i < tot; i++) {
-    CustomDataLayer *layer =
-        &mesh_src->vdata.layers[CustomData_get_layer_index_n(&mesh_src->vdata, CD_SHAPEKEY, i)];
-    float(*kbcos)[3];
-
-    for (kb = (KeyBlock *)mesh_dst->key->block.first; kb; kb = kb->next) {
-      if (kb->uid == layer->uid) {
-        break;
-      }
-    }
+static int find_object_active_key_uid(const Key &key, const Object &object)
+{
+  const int active_kb_index = object.shapenr - 1;
+  const KeyBlock *kb = (const KeyBlock *)BLI_findlink(&key.block, active_kb_index);
+  if (!kb) {
+    CLOG_ERROR(&LOG, "Could not find object's active shapekey %d", active_kb_index);
+    return -1;
+  }
+  return kb->uid;
+}
 
-    if (!kb) {
-      kb = BKE_keyblock_add(mesh_dst->key, layer->name);
-      kb->uid = layer->uid;
-    }
+static void move_shapekey_layers_to_keyblocks(Mesh &mesh, Key &key_dst, const int actshape_uid)
+{
+  using namespace blender::bke;
+  for (const int i : IndexRange(CustomData_number_of_layers(&mesh.vdata, CD_SHAPEKEY))) {
+    const int layer_index = CustomData_get_layer_index_n(&mesh.vdata, CD_SHAPEKEY, i);
+    CustomDataLayer &layer = mesh.vdata.layers[layer_index];
 
-    if (kb->data) {
-      MEM_freeN(kb->data);
-    }
+    KeyBlock *kb = keyblock_ensure_from_uid(key_dst, layer.uid, layer.name);
+    MEM_SAFE_FREE(kb->data);
 
-    const float(*cos)[3] = (const float(*)[3])CustomData_get_layer_n(
-        &mesh_src->vdata, CD_SHAPEKEY, i);
-    kb->totelem = mesh_src->totvert;
+    kb->totelem = mesh.totvert;
 
-    kb->data = kbcos = (float(*)[3])MEM_malloc_arrayN(kb->totelem, sizeof(float[3]), __func__);
     if (kb->uid == actshape_uid) {
-      MVert *mvert = mesh_src->mvert;
-
-      for (j = 0; j < mesh_src->totvert; j++, kbcos++, mvert++) {
-        copy_v3_v3(*kbcos, mvert->co);
-      }
+      kb->data = MEM_malloc_arrayN(kb->totelem, sizeof(float3), __func__);
+      MutableSpan kb_coords(static_cast(kb->data), kb->totelem);
+      mesh.attributes().lookup("position").materialize(kb_coords);
     }
     else {
-      for (j = 0; j < kb->totelem; j++, cos++, kbcos++) {
-        copy_v3_v3(*kbcos, *cos);
-      }
+      kb->data = layer.data;
+      layer.data = nullptr;
     }
   }
 
-  for (kb = (KeyBlock *)mesh_dst->key->block.first; kb; kb = kb->next) {
-    if (kb->totelem != mesh_src->totvert) {
-      if (kb->data) {
-        MEM_freeN(kb->data);
-      }
-
-      kb->totelem = mesh_src->totvert;
-      kb->data = MEM_calloc_arrayN(kb->totelem, sizeof(float[3]), __func__);
-      CLOG_ERROR(&LOG, "lost a shapekey layer: '%s'! (bmesh internal error)", kb->name);
+  LISTBASE_FOREACH (KeyBlock *, kb, &key_dst.block) {
+    if (kb->totelem != mesh.totvert) {
+      MEM_SAFE_FREE(kb->data);
     }
+    kb->totelem = mesh.totvert;
+    kb->data = MEM_cnew_array(kb->totelem, __func__);
+    CLOG_ERROR(&LOG, "Data for shape key '%s' on mesh missing from evaluated mesh ", kb->name);
   }
 }
 
-void BKE_mesh_nomain_to_mesh(Mesh *mesh_src,
-                             Mesh *mesh_dst,
-                             Object *ob,
-                             const CustomData_MeshMasks *mask,
-                             bool take_ownership)
+void BKE_mesh_nomain_to_mesh(Mesh *mesh_src, Mesh *mesh_dst, Object *ob)
 {
+  using namespace blender::bke;
   BLI_assert(mesh_src->id.tag & LIB_TAG_NO_MAIN);
-
-  /* mesh_src might depend on mesh_dst, so we need to do everything with a local copy */
-  /* TODO(Sybren): the above claim came from 2.7x derived-mesh code (DM_to_mesh);
-   * check whether it is still true with Mesh */
-  Mesh tmp = blender::dna::shallow_copy(*mesh_dst);
-  int totvert, totedge /*, totface */ /* UNUSED */, totloop, totpoly;
-  bool did_shapekeys = false;
-  eCDAllocType alloctype = CD_DUPLICATE;
-
-  if (take_ownership /* && dm->type == DM_TYPE_CDDM && dm->needsFree */) {
-    bool has_any_referenced_layers = CustomData_has_referenced(&mesh_src->vdata) ||
-                                     CustomData_has_referenced(&mesh_src->edata) ||
-                                     CustomData_has_referenced(&mesh_src->ldata) ||
-                                     CustomData_has_referenced(&mesh_src->fdata) ||
-                                     CustomData_has_referenced(&mesh_src->pdata);
-    if (!has_any_referenced_layers) {
-      alloctype = CD_ASSIGN;
-    }
-  }
-  CustomData_reset(&tmp.vdata);
-  CustomData_reset(&tmp.edata);
-  CustomData_reset(&tmp.fdata);
-  CustomData_reset(&tmp.ldata);
-  CustomData_reset(&tmp.pdata);
-
-  totvert = tmp.totvert = mesh_src->totvert;
-  totedge = tmp.totedge = mesh_src->totedge;
-  totloop = tmp.totloop = mesh_src->totloop;
-  totpoly = tmp.totpoly = mesh_src->totpoly;
-  tmp.totface = 0;
-
-  CustomData_copy(&mesh_src->vdata, &tmp.vdata, mask->vmask, alloctype, totvert);
-  CustomData_copy(&mesh_src->edata, &tmp.edata, mask->emask, alloctype, totedge);
-  CustomData_copy(&mesh_src->ldata, &tmp.ldata, mask->lmask, alloctype, totloop);
-  CustomData_copy(&mesh_src->pdata, &tmp.pdata, mask->pmask, alloctype, totpoly);
-  tmp.cd_flag = mesh_src->cd_flag;
-  tmp.runtime.deformed_only = mesh_src->runtime.deformed_only;
-
-  /* Clear the normals completely, since the new vertex / polygon count might be different. */
-  BKE_mesh_clear_derived_normals(&tmp);
-
-  if (CustomData_has_layer(&mesh_src->vdata, CD_SHAPEKEY)) {
-    KeyBlock *kb;
-    int uid;
-
-    if (ob) {
-      kb = (KeyBlock *)BLI_findlink(&mesh_dst->key->block, ob->shapenr - 1);
-      if (kb) {
-        uid = kb->uid;
-      }
-      else {
-        CLOG_ERROR(&LOG, "could not find active shapekey %d!", ob->shapenr - 1);
-
-        uid = INT_MAX;
-      }
-    }
-    else {
-      /* if no object, set to INT_MAX so we don't mess up any shapekey layers */
-      uid = INT_MAX;
-    }
-
-    shapekey_layers_to_keyblocks(mesh_src, mesh_dst, uid);
-    did_shapekeys = true;
-  }
-
-  /* copy texture space */
   if (ob) {
-    BKE_mesh_texspace_copy_from_object(&tmp, ob);
+    BLI_assert(mesh_dst == ob->data);
   }
 
-  /* not all DerivedMeshes store their verts/edges/faces in CustomData, so
-   * we set them here in case they are missing */
-  /* TODO(Sybren): we could probably replace CD_ASSIGN with alloctype and
-   * always directly pass mesh_src->mxxx, instead of using a ternary operator. */
-  if (!CustomData_has_layer(&tmp.vdata, CD_MVERT)) {
-    CustomData_add_layer(&tmp.vdata,
-                         CD_MVERT,
-                         CD_ASSIGN,
-                         (alloctype == CD_ASSIGN) ? mesh_src->mvert :
-                                                    MEM_dupallocN(mesh_src->mvert),
-                         totvert);
-  }
-  if (!CustomData_has_layer(&tmp.edata, CD_MEDGE)) {
-    CustomData_add_layer(&tmp.edata,
-                         CD_MEDGE,
-                         CD_ASSIGN,
-                         (alloctype == CD_ASSIGN) ? mesh_src->medge :
-                                                    MEM_dupallocN(mesh_src->medge),
-                         totedge);
-  }
-  if (!CustomData_has_layer(&tmp.pdata, CD_MPOLY)) {
-    CustomData_add_layer(&tmp.ldata,
-                         CD_MLOOP,
-                         CD_ASSIGN,
-                         (alloctype == CD_ASSIGN) ? mesh_src->mloop :
-                                                    MEM_dupallocN(mesh_src->mloop),
-                         tmp.totloop);
-    CustomData_add_layer(&tmp.pdata,
-                         CD_MPOLY,
-                         CD_ASSIGN,
-                         (alloctype == CD_ASSIGN) ? mesh_src->mpoly :
-                                                    MEM_dupallocN(mesh_src->mpoly),
-                         tmp.totpoly);
-  }
+  BKE_mesh_clear_geometry(mesh_dst);
 
-  /* object had got displacement layer, should copy this layer to save sculpted data */
-  /* NOTE(nazgul): maybe some other layers should be copied? */
-  if (CustomData_has_layer(&mesh_dst->ldata, CD_MDISPS)) {
-    if (totloop == mesh_dst->totloop) {
-      MDisps *mdisps = (MDisps *)CustomData_get_layer(&mesh_dst->ldata, CD_MDISPS);
-      CustomData_add_layer(&tmp.ldata, CD_MDISPS, alloctype, mdisps, totloop);
-      if (alloctype == CD_ASSIGN) {
-        /* Assign nullptr to prevent double-free. */
-        CustomData_set_layer(&mesh_dst->ldata, CD_MDISPS, nullptr);
-      }
-    }
-  }
+  /* Make sure referenced layers have a single user so assigning them to the mesh in main doesn't
+   * share them. "Referenced" layers are not expected to be shared between original meshes. */
+  CustomData_duplicate_referenced_layers(&mesh_src->vdata, mesh_src->totvert);
+  CustomData_duplicate_referenced_layers(&mesh_src->edata, mesh_src->totedge);
+  CustomData_duplicate_referenced_layers(&mesh_src->pdata, mesh_src->totpoly);
+  CustomData_duplicate_referenced_layers(&mesh_src->ldata, mesh_src->totloop);
 
-  /* yes, must be before _and_ after tessellate */
-  BKE_mesh_update_customdata_pointers(&tmp, false);
-
-  CustomData_free(&mesh_dst->vdata, mesh_dst->totvert);
-  CustomData_free(&mesh_dst->edata, mesh_dst->totedge);
-  CustomData_free(&mesh_dst->fdata, mesh_dst->totface);
-  CustomData_free(&mesh_dst->ldata, mesh_dst->totloop);
-  CustomData_free(&mesh_dst->pdata, mesh_dst->totpoly);
-
-  /* ok, this should now use new CD shapekey data,
-   * which should be fed through the modifier
-   * stack */
-  if (tmp.totvert != mesh_dst->totvert && !did_shapekeys && mesh_dst->key) {
-    CLOG_ERROR(&LOG, "YEEK! this should be recoded! Shape key loss!: ID '%s'", tmp.id.name);
-    if (tmp.key && !(tmp.id.tag & LIB_TAG_NO_MAIN)) {
-      id_us_min(&tmp.key->id);
-    }
-    tmp.key = nullptr;
-  }
+  mesh_dst->totvert = mesh_src->totvert;
+  mesh_dst->totedge = mesh_src->totedge;
+  mesh_dst->totpoly = mesh_src->totpoly;
+  mesh_dst->totloop = mesh_src->totloop;
 
-  /* Clear selection history */
-  MEM_SAFE_FREE(tmp.mselect);
-  tmp.totselect = 0;
-  tmp.texflag &= ~ME_AUTOSPACE_EVALUATED;
-
-  /* Clear any run-time data.
-   * Even though this mesh won't typically have run-time data, the Python API can for e.g.
-   * create loop-triangle cache here, which is confusing when left in the mesh, see: T81136. */
-  BKE_mesh_runtime_clear_geometry(&tmp);
-
-  /* skip the listbase */
-  MEMCPY_STRUCT_AFTER(mesh_dst, &tmp, id.prev);
+  /* Using #CD_MASK_MESH ensures that only data that should exist in Main meshes is moved. */
+  const CustomData_MeshMasks mask = CD_MASK_MESH;
+  CustomData_copy(&mesh_src->vdata, &mesh_dst->vdata, mask.vmask, CD_ASSIGN, mesh_src->totvert);
+  CustomData_copy(&mesh_src->edata, &mesh_dst->edata, mask.emask, CD_ASSIGN, mesh_src->totedge);
+  CustomData_copy(&mesh_src->pdata, &mesh_dst->pdata, mask.pmask, CD_ASSIGN, mesh_src->totpoly);
+  CustomData_copy(&mesh_src->ldata, &mesh_dst->ldata, mask.lmask, CD_ASSIGN, mesh_src->totloop);
 
   BLI_freelistN(&mesh_dst->vertex_group_names);
-  BKE_defgroup_copy_list(&mesh_dst->vertex_group_names, &mesh_src->vertex_group_names);
-  mesh_dst->vertex_group_active_index = mesh_src->vertex_group_active_index;
-
-  if (take_ownership) {
-    if (alloctype == CD_ASSIGN) {
-      CustomData_free_typemask(&mesh_src->vdata, mesh_src->totvert, ~mask->vmask);
-      CustomData_free_typemask(&mesh_src->edata, mesh_src->totedge, ~mask->emask);
-      CustomData_free_typemask(&mesh_src->ldata, mesh_src->totloop, ~mask->lmask);
-      CustomData_free_typemask(&mesh_src->pdata, mesh_src->totpoly, ~mask->pmask);
+  mesh_dst->vertex_group_names = mesh_src->vertex_group_names;
+  BLI_listbase_clear(&mesh_src->vertex_group_names);
+
+  BKE_mesh_copy_parameters(mesh_dst, mesh_src);
+  mesh_dst->cd_flag = mesh_src->cd_flag;
+
+  /* For original meshes, shape key data is stored in the #Key data-block, so it
+   * must be moved from the storage in #CustomData layers used for evaluation. */
+  if (Key *key_dst = mesh_dst->key) {
+    if (CustomData_has_layer(&mesh_src->vdata, CD_SHAPEKEY)) {
+      /* If no object, set to -1 so we don't mess up any shapekey layers. */
+      const int uid_active = ob ? find_object_active_key_uid(*key_dst, *ob) : -1;
+      move_shapekey_layers_to_keyblocks(*mesh_src, *key_dst, uid_active);
+    }
+    else if (mesh_src->totvert != mesh_dst->totvert) {
+      CLOG_ERROR(&LOG, "Mesh in Main '%s' lost shape keys", mesh_src->id.name);
+      if (mesh_src->key) {
+        id_us_min(&mesh_src->key->id);
+      }
     }
-    BKE_id_free(nullptr, mesh_src);
   }
 
-  BKE_mesh_assert_normals_dirty_or_calculated(mesh_dst);
+  BKE_id_free(nullptr, mesh_src);
 }
 
 void BKE_mesh_nomain_to_meshkey(Mesh *mesh_src, Mesh *mesh_dst, KeyBlock *kb)
@@ -1603,7 +1355,6 @@ void BKE_mesh_nomain_to_meshkey(Mesh *mesh_src, Mesh *mesh_dst, KeyBlock *kb)
 
   int a, totvert = mesh_src->totvert;
   float *fp;
-  MVert *mvert;
 
   if (totvert == 0 || mesh_dst->totvert == 0 || mesh_dst->totvert != totvert) {
     return;
@@ -1616,9 +1367,8 @@ void BKE_mesh_nomain_to_meshkey(Mesh *mesh_src, Mesh *mesh_dst, KeyBlock *kb)
   kb->totelem = totvert;
 
   fp = (float *)kb->data;
-  mvert = mesh_src->mvert;
-
-  for (a = 0; a < kb->totelem; a++, fp += 3, mvert++) {
-    copy_v3_v3(fp, mvert->co);
+  const Span verts = mesh_src->verts();
+  for (a = 0; a < kb->totelem; a++, fp += 3) {
+    copy_v3_v3(fp, verts[a].co);
   }
 }
diff --git a/source/blender/blenkernel/intern/mesh_debug.cc b/source/blender/blenkernel/intern/mesh_debug.cc
index 6f12726d364..8a9ce901923 100644
--- a/source/blender/blenkernel/intern/mesh_debug.cc
+++ b/source/blender/blenkernel/intern/mesh_debug.cc
@@ -30,12 +30,6 @@
 static void mesh_debug_info_from_cd_flag(const Mesh *me, DynStr *dynstr)
 {
   BLI_dynstr_append(dynstr, "'cd_flag': {");
-  if (me->cd_flag & ME_CDFLAG_VERT_BWEIGHT) {
-    BLI_dynstr_append(dynstr, "'VERT_BWEIGHT', ");
-  }
-  if (me->cd_flag & ME_CDFLAG_EDGE_BWEIGHT) {
-    BLI_dynstr_append(dynstr, "'EDGE_BWEIGHT', ");
-  }
   if (me->cd_flag & ME_CDFLAG_EDGE_CREASE) {
     BLI_dynstr_append(dynstr, "'EDGE_CREASE', ");
   }
@@ -58,7 +52,8 @@ char *BKE_mesh_debug_info(const Mesh *me)
   BLI_dynstr_appendf(dynstr, "    'totpoly': %d,\n", me->totpoly);
 
   BLI_dynstr_appendf(dynstr, "    'runtime.deformed_only': %d,\n", me->runtime.deformed_only);
-  BLI_dynstr_appendf(dynstr, "    'runtime.is_original': %d,\n", me->runtime.is_original);
+  BLI_dynstr_appendf(
+      dynstr, "    'runtime.is_original_bmesh': %d,\n", me->runtime.is_original_bmesh);
 
   BLI_dynstr_append(dynstr, "    'vert_layers': (\n");
   CustomData_debug_info_from_layers(&me->vdata, indent8, dynstr);
diff --git a/source/blender/blenkernel/intern/mesh_evaluate.cc b/source/blender/blenkernel/intern/mesh_evaluate.cc
index 7d26262a504..938d7e42aa3 100644
--- a/source/blender/blenkernel/intern/mesh_evaluate.cc
+++ b/source/blender/blenkernel/intern/mesh_evaluate.cc
@@ -22,15 +22,17 @@
 #include "BLI_math.h"
 #include "BLI_span.hh"
 #include "BLI_utildefines.h"
+#include "BLI_virtual_array.hh"
 
 #include "BKE_customdata.h"
 
+#include "BKE_attribute.hh"
 #include "BKE_mesh.h"
 #include "BKE_multires.h"
 
-using blender::IndexRange;
 using blender::MutableSpan;
 using blender::Span;
+using blender::VArray;
 
 /* -------------------------------------------------------------------- */
 /** \name Polygon Calculations
@@ -203,18 +205,13 @@ float BKE_mesh_calc_poly_area(const MPoly *mpoly, const MLoop *loopstart, const
 
 float BKE_mesh_calc_area(const Mesh *me)
 {
-  MVert *mvert = me->mvert;
-  MLoop *mloop = me->mloop;
-  MPoly *mpoly = me->mpoly;
+  const Span verts = me->verts();
+  const Span polys = me->polys();
+  const Span loops = me->loops();
 
-  MPoly *mp;
-  int i = me->totpoly;
-  float total_area = 0;
-
-  for (mp = mpoly; i--; mp++) {
-    MLoop *ml_start = &mloop[mp->loopstart];
-
-    total_area += BKE_mesh_calc_poly_area(mp, ml_start, mvert);
+  float total_area = 0.0f;
+  for (const MPoly &poly : polys) {
+    total_area += BKE_mesh_calc_poly_area(&poly, &loops[poly.loopstart], verts.data());
   }
   return total_area;
 }
@@ -403,11 +400,10 @@ void BKE_mesh_poly_edgebitmap_insert(uint *edge_bitmap, const MPoly *mp, const M
 
 bool BKE_mesh_center_median(const Mesh *me, float r_cent[3])
 {
-  int i = me->totvert;
-  const MVert *mvert;
+  const Span verts = me->verts();
   zero_v3(r_cent);
-  for (mvert = me->mvert; i--; mvert++) {
-    add_v3_v3(r_cent, mvert->co);
+  for (const MVert &vert : verts) {
+    add_v3_v3(r_cent, vert.co);
   }
   /* otherwise we get NAN for 0 verts */
   if (me->totvert) {
@@ -418,18 +414,17 @@ bool BKE_mesh_center_median(const Mesh *me, float r_cent[3])
 
 bool BKE_mesh_center_median_from_polys(const Mesh *me, float r_cent[3])
 {
-  int i = me->totpoly;
   int tot = 0;
-  const MPoly *mpoly = me->mpoly;
-  const MLoop *mloop = me->mloop;
-  const MVert *mvert = me->mvert;
+  const Span verts = me->verts();
+  const Span polys = me->polys();
+  const Span loops = me->loops();
   zero_v3(r_cent);
-  for (; i--; mpoly++) {
-    int loopend = mpoly->loopstart + mpoly->totloop;
-    for (int j = mpoly->loopstart; j < loopend; j++) {
-      add_v3_v3(r_cent, mvert[mloop[j].v].co);
+  for (const MPoly &poly : polys) {
+    int loopend = poly.loopstart + poly.totloop;
+    for (int j = poly.loopstart; j < loopend; j++) {
+      add_v3_v3(r_cent, verts[loops[j].v].co);
     }
-    tot += mpoly->totloop;
+    tot += poly.totloop;
   }
   /* otherwise we get NAN for 0 verts */
   if (me->totpoly) {
@@ -453,17 +448,19 @@ bool BKE_mesh_center_bounds(const Mesh *me, float r_cent[3])
 bool BKE_mesh_center_of_surface(const Mesh *me, float r_cent[3])
 {
   int i = me->totpoly;
-  MPoly *mpoly;
+  const MPoly *mpoly;
   float poly_area;
   float total_area = 0.0f;
   float poly_cent[3];
+  const MVert *verts = BKE_mesh_verts(me);
+  const MPoly *polys = BKE_mesh_polys(me);
+  const MLoop *loops = BKE_mesh_loops(me);
 
   zero_v3(r_cent);
 
   /* calculate a weighted average of polygon centroids */
-  for (mpoly = me->mpoly; i--; mpoly++) {
-    poly_area = mesh_calc_poly_area_centroid(
-        mpoly, me->mloop + mpoly->loopstart, me->mvert, poly_cent);
+  for (mpoly = polys; i--; mpoly++) {
+    poly_area = mesh_calc_poly_area_centroid(mpoly, loops + mpoly->loopstart, verts, poly_cent);
 
     madd_v3_v3fl(r_cent, poly_cent, poly_area);
     total_area += poly_area;
@@ -484,10 +481,13 @@ bool BKE_mesh_center_of_surface(const Mesh *me, float r_cent[3])
 bool BKE_mesh_center_of_volume(const Mesh *me, float r_cent[3])
 {
   int i = me->totpoly;
-  MPoly *mpoly;
+  const MPoly *mpoly;
   float poly_volume;
   float total_volume = 0.0f;
   float poly_cent[3];
+  const MVert *verts = BKE_mesh_verts(me);
+  const MPoly *polys = BKE_mesh_polys(me);
+  const MLoop *loops = BKE_mesh_loops(me);
 
   /* Use an initial center to avoid numeric instability of geometry far away from the center. */
   float init_cent[3];
@@ -496,9 +496,9 @@ bool BKE_mesh_center_of_volume(const Mesh *me, float r_cent[3])
   zero_v3(r_cent);
 
   /* calculate a weighted average of polyhedron centroids */
-  for (mpoly = me->mpoly; i--; mpoly++) {
+  for (mpoly = polys; i--; mpoly++) {
     poly_volume = mesh_calc_poly_volume_centroid_with_reference_center(
-        mpoly, me->mloop + mpoly->loopstart, me->mvert, init_cent, poly_cent);
+        mpoly, loops + mpoly->loopstart, verts, init_cent, poly_cent);
 
     /* poly_cent is already volume-weighted, so no need to multiply by the volume */
     add_v3_v3(r_cent, poly_cent);
@@ -668,7 +668,7 @@ void BKE_mesh_mdisp_flip(MDisps *md, const bool use_loop_mdisp_flip)
   }
 }
 
-void BKE_mesh_polygon_flip_ex(MPoly *mpoly,
+void BKE_mesh_polygon_flip_ex(const MPoly *mpoly,
                               MLoop *mloop,
                               CustomData *ldata,
                               float (*lnors)[3],
@@ -711,16 +711,16 @@ void BKE_mesh_polygon_flip_ex(MPoly *mpoly,
   }
 }
 
-void BKE_mesh_polygon_flip(MPoly *mpoly, MLoop *mloop, CustomData *ldata)
+void BKE_mesh_polygon_flip(const MPoly *mpoly, MLoop *mloop, CustomData *ldata)
 {
   MDisps *mdisp = (MDisps *)CustomData_get_layer(ldata, CD_MDISPS);
   BKE_mesh_polygon_flip_ex(mpoly, mloop, ldata, nullptr, mdisp, true);
 }
 
-void BKE_mesh_polygons_flip(MPoly *mpoly, MLoop *mloop, CustomData *ldata, int totpoly)
+void BKE_mesh_polys_flip(const MPoly *mpoly, MLoop *mloop, CustomData *ldata, int totpoly)
 {
   MDisps *mdisp = (MDisps *)CustomData_get_layer(ldata, CD_MDISPS);
-  MPoly *mp;
+  const MPoly *mp;
   int i;
 
   for (mp = mpoly, i = 0; i < totpoly; mp++, i++) {
@@ -732,75 +732,90 @@ void BKE_mesh_polygons_flip(MPoly *mpoly, MLoop *mloop, CustomData *ldata, int t
 /** \name Mesh Flag Flushing
  * \{ */
 
-void BKE_mesh_flush_hidden_from_verts_ex(const MVert *mvert,
-                                         const MLoop *mloop,
-                                         MEdge *medge,
-                                         const int totedge,
-                                         MPoly *mpoly,
-                                         const int totpoly)
+void BKE_mesh_flush_hidden_from_verts(Mesh *me)
 {
-  int i, j;
+  using namespace blender;
+  using namespace blender::bke;
+  MutableAttributeAccessor attributes = me->attributes_for_write();
 
-  for (i = 0; i < totedge; i++) {
-    MEdge *e = &medge[i];
-    if (mvert[e->v1].flag & ME_HIDE || mvert[e->v2].flag & ME_HIDE) {
-      e->flag |= ME_HIDE;
-    }
-    else {
-      e->flag &= ~ME_HIDE;
-    }
+  const VArray hide_vert = attributes.lookup_or_default(
+      ".hide_vert", ATTR_DOMAIN_POINT, false);
+  if (hide_vert.is_single() && !hide_vert.get_internal_single()) {
+    attributes.remove(".hide_edge");
+    attributes.remove(".hide_poly");
+    return;
   }
-  for (i = 0; i < totpoly; i++) {
-    MPoly *p = &mpoly[i];
-    p->flag &= (char)~ME_HIDE;
-    for (j = 0; j < p->totloop; j++) {
-      if (mvert[mloop[p->loopstart + j].v].flag & ME_HIDE) {
-        p->flag |= ME_HIDE;
-      }
-    }
+  const VArraySpan hide_vert_span{hide_vert};
+  const Span edges = me->edges();
+  const Span polys = me->polys();
+  const Span loops = me->loops();
+
+  /* Hide edges when either of their vertices are hidden. */
+  SpanAttributeWriter hide_edge = attributes.lookup_or_add_for_write_only_span(
+      ".hide_edge", ATTR_DOMAIN_EDGE);
+  for (const int i : edges.index_range()) {
+    const MEdge &edge = edges[i];
+    hide_edge.span[i] = hide_vert_span[edge.v1] || hide_vert_span[edge.v2];
   }
-}
-void BKE_mesh_flush_hidden_from_verts(Mesh *me)
-{
-  BKE_mesh_flush_hidden_from_verts_ex(
-      me->mvert, me->mloop, me->medge, me->totedge, me->mpoly, me->totpoly);
+  hide_edge.finish();
+
+  /* Hide polygons when any of their vertices are hidden. */
+  SpanAttributeWriter hide_poly = attributes.lookup_or_add_for_write_only_span(
+      ".hide_poly", ATTR_DOMAIN_FACE);
+  for (const int i : polys.index_range()) {
+    const MPoly &poly = polys[i];
+    const Span poly_loops = loops.slice(poly.loopstart, poly.totloop);
+    hide_poly.span[i] = std::any_of(poly_loops.begin(), poly_loops.end(), [&](const MLoop &loop) {
+      return hide_vert_span[loop.v];
+    });
+  }
+  hide_poly.finish();
 }
 
-void BKE_mesh_flush_hidden_from_polys_ex(MVert *mvert,
-                                         const MLoop *mloop,
-                                         MEdge *medge,
-                                         const int UNUSED(totedge),
-                                         const MPoly *mpoly,
-                                         const int totpoly)
+void BKE_mesh_flush_hidden_from_polys(Mesh *me)
 {
-  int i = totpoly;
-  for (const MPoly *mp = mpoly; i--; mp++) {
-    if (mp->flag & ME_HIDE) {
-      const MLoop *ml;
-      int j = mp->totloop;
-      for (ml = &mloop[mp->loopstart]; j--; ml++) {
-        mvert[ml->v].flag |= ME_HIDE;
-        medge[ml->e].flag |= ME_HIDE;
+  using namespace blender;
+  using namespace blender::bke;
+  MutableAttributeAccessor attributes = me->attributes_for_write();
+
+  const VArray hide_poly = attributes.lookup_or_default(
+      ".hide_poly", ATTR_DOMAIN_FACE, false);
+  if (hide_poly.is_single() && !hide_poly.get_internal_single()) {
+    attributes.remove(".hide_vert");
+    attributes.remove(".hide_edge");
+    return;
+  }
+  const VArraySpan hide_poly_span{hide_poly};
+  const Span polys = me->polys();
+  const Span loops = me->loops();
+  SpanAttributeWriter hide_vert = attributes.lookup_or_add_for_write_only_span(
+      ".hide_vert", ATTR_DOMAIN_POINT);
+  SpanAttributeWriter hide_edge = attributes.lookup_or_add_for_write_only_span(
+      ".hide_edge", ATTR_DOMAIN_EDGE);
+
+  /* Hide all edges or vertices connected to hidden polygons. */
+  for (const int i : polys.index_range()) {
+    if (hide_poly_span[i]) {
+      const MPoly &poly = polys[i];
+      for (const MLoop &loop : loops.slice(poly.loopstart, poly.totloop)) {
+        hide_vert.span[loop.v] = true;
+        hide_edge.span[loop.e] = true;
       }
     }
   }
-
-  i = totpoly;
-  for (const MPoly *mp = mpoly; i--; mp++) {
-    if ((mp->flag & ME_HIDE) == 0) {
-      const MLoop *ml;
-      int j = mp->totloop;
-      for (ml = &mloop[mp->loopstart]; j--; ml++) {
-        mvert[ml->v].flag &= (char)~ME_HIDE;
-        medge[ml->e].flag &= (short)~ME_HIDE;
+  /* Unhide vertices and edges connected to visible polygons. */
+  for (const int i : polys.index_range()) {
+    if (!hide_poly_span[i]) {
+      const MPoly &poly = polys[i];
+      for (const MLoop &loop : loops.slice(poly.loopstart, poly.totloop)) {
+        hide_vert.span[loop.v] = false;
+        hide_edge.span[loop.e] = false;
       }
     }
   }
-}
-void BKE_mesh_flush_hidden_from_polys(Mesh *me)
-{
-  BKE_mesh_flush_hidden_from_polys_ex(
-      me->mvert, me->mloop, me->medge, me->totedge, me->mpoly, me->totpoly);
+
+  hide_vert.finish();
+  hide_edge.finish();
 }
 
 void BKE_mesh_flush_select_from_polys_ex(MVert *mvert,
@@ -842,17 +857,24 @@ void BKE_mesh_flush_select_from_polys_ex(MVert *mvert,
 }
 void BKE_mesh_flush_select_from_polys(Mesh *me)
 {
-  BKE_mesh_flush_select_from_polys_ex(
-      me->mvert, me->totvert, me->mloop, me->medge, me->totedge, me->mpoly, me->totpoly);
+  BKE_mesh_flush_select_from_polys_ex(me->verts_for_write().data(),
+                                      me->totvert,
+                                      me->loops().data(),
+                                      me->edges_for_write().data(),
+                                      me->totedge,
+                                      me->polys().data(),
+                                      me->totpoly);
 }
 
 static void mesh_flush_select_from_verts(const Span verts,
                                          const Span loops,
+                                         const VArray &hide_edge,
+                                         const VArray &hide_poly,
                                          MutableSpan edges,
                                          MutableSpan polys)
 {
   for (const int i : edges.index_range()) {
-    if ((edges[i].flag & ME_HIDE) == 0) {
+    if (!hide_edge[i]) {
       MEdge &edge = edges[i];
       if ((verts[edge.v1].flag & SELECT) && (verts[edge.v2].flag & SELECT)) {
         edge.flag |= SELECT;
@@ -864,7 +886,7 @@ static void mesh_flush_select_from_verts(const Span verts,
   }
 
   for (const int i : polys.index_range()) {
-    if (polys[i].flag & ME_HIDE) {
+    if (hide_poly[i]) {
       continue;
     }
     MPoly &poly = polys[i];
@@ -885,10 +907,14 @@ static void mesh_flush_select_from_verts(const Span verts,
 
 void BKE_mesh_flush_select_from_verts(Mesh *me)
 {
-  mesh_flush_select_from_verts({me->mvert, me->totvert},
-                               {me->mloop, me->totloop},
-                               {me->medge, me->totedge},
-                               {me->mpoly, me->totpoly});
+  const blender::bke::AttributeAccessor attributes = me->attributes();
+  mesh_flush_select_from_verts(
+      me->verts(),
+      me->loops(),
+      attributes.lookup_or_default(".hide_edge", ATTR_DOMAIN_EDGE, false),
+      attributes.lookup_or_default(".hide_poly", ATTR_DOMAIN_FACE, false),
+      me->edges_for_write(),
+      me->polys_for_write());
 }
 
 /** \} */
diff --git a/source/blender/blenkernel/intern/mesh_fair.cc b/source/blender/blenkernel/intern/mesh_fair.cc
index 8936d7b0ba6..41dcb3501cc 100644
--- a/source/blender/blenkernel/intern/mesh_fair.cc
+++ b/source/blender/blenkernel/intern/mesh_fair.cc
@@ -27,6 +27,8 @@
 #include "eigen_capi.h"
 
 using blender::Map;
+using blender::MutableSpan;
+using blender::Span;
 using blender::Vector;
 using std::array;
 
@@ -74,13 +76,13 @@ class FairingContext {
 
   virtual ~FairingContext() = default;
 
-  void fair_vertices(bool *affected,
-                     const eMeshFairingDepth depth,
-                     VertexWeight *vertex_weight,
-                     LoopWeight *loop_weight)
+  void fair_verts(bool *affected,
+                  const eMeshFairingDepth depth,
+                  VertexWeight *vertex_weight,
+                  LoopWeight *loop_weight)
   {
 
-    fair_vertices_ex(affected, (int)depth, vertex_weight, loop_weight);
+    fair_verts_ex(affected, (int)depth, vertex_weight, loop_weight);
   }
 
  protected:
@@ -141,28 +143,28 @@ class FairingContext {
                        loop_weight);
   }
 
-  void fair_vertices_ex(const bool *affected,
-                        const int order,
-                        VertexWeight *vertex_weight,
-                        LoopWeight *loop_weight)
+  void fair_verts_ex(const bool *affected,
+                     const int order,
+                     VertexWeight *vertex_weight,
+                     LoopWeight *loop_weight)
   {
     Map vert_col_map;
-    int num_affected_vertices = 0;
+    int affected_verts_num = 0;
     for (int i = 0; i < totvert_; i++) {
       if (!affected[i]) {
         continue;
       }
-      vert_col_map.add(i, num_affected_vertices);
-      num_affected_vertices++;
+      vert_col_map.add(i, affected_verts_num);
+      affected_verts_num++;
     }
 
     /* Early return, nothing to do. */
-    if (ELEM(num_affected_vertices, 0, totvert_)) {
+    if (ELEM(affected_verts_num, 0, totvert_)) {
       return;
     }
 
     /* Setup fairing matrices */
-    LinearSolver *solver = EIG_linear_solver_new(num_affected_vertices, num_affected_vertices, 3);
+    LinearSolver *solver = EIG_linear_solver_new(affected_verts_num, affected_verts_num, 3);
     for (auto item : vert_col_map.items()) {
       const int v = item.key;
       const int col = item.value;
@@ -193,13 +195,14 @@ class MeshFairingContext : public FairingContext {
     totvert_ = mesh->totvert;
     totloop_ = mesh->totloop;
 
-    medge_ = mesh->medge;
-    mpoly_ = mesh->mpoly;
-    mloop_ = mesh->mloop;
+    MutableSpan verts = mesh->verts_for_write();
+    medge_ = mesh->edges();
+    mpoly_ = mesh->polys();
+    mloop_ = mesh->loops();
     BKE_mesh_vert_loop_map_create(&vlmap_,
                                   &vlmap_mem_,
-                                  mesh->mpoly,
-                                  mesh->mloop,
+                                  mpoly_.data(),
+                                  mloop_.data(),
                                   mesh->totvert,
                                   mesh->totpoly,
                                   mesh->totloop);
@@ -213,14 +216,14 @@ class MeshFairingContext : public FairingContext {
     }
     else {
       for (int i = 0; i < mesh->totvert; i++) {
-        co_[i] = mesh->mvert[i].co;
+        co_[i] = verts[i].co;
       }
     }
 
     loop_to_poly_map_.reserve(mesh->totloop);
     for (int i = 0; i < mesh->totpoly; i++) {
-      for (int l = 0; l < mesh->mpoly[i].totloop; l++) {
-        loop_to_poly_map_[l + mesh->mpoly[i].loopstart] = i;
+      for (int l = 0; l < mpoly_[i].totloop; l++) {
+        loop_to_poly_map_[l + mpoly_[i].loopstart] = i;
       }
     }
   }
@@ -244,7 +247,7 @@ class MeshFairingContext : public FairingContext {
 
   int other_vertex_index_from_loop(const int loop, const uint v) override
   {
-    MEdge *e = &medge_[mloop_[loop].e];
+    const MEdge *e = &medge_[mloop_[loop].e];
     if (e->v1 == v) {
       return e->v2;
     }
@@ -253,9 +256,9 @@ class MeshFairingContext : public FairingContext {
 
  protected:
   Mesh *mesh_;
-  MLoop *mloop_;
-  MPoly *mpoly_;
-  MEdge *medge_;
+  Span mloop_;
+  Span mpoly_;
+  Span medge_;
   Vector loop_to_poly_map_;
 };
 
@@ -447,42 +450,40 @@ class UniformLoopWeight : public LoopWeight {
   }
 };
 
-static void prefair_and_fair_vertices(FairingContext *fairing_context,
-                                      bool *affected_vertices,
-                                      const eMeshFairingDepth depth)
+static void prefair_and_fair_verts(FairingContext *fairing_context,
+                                   bool *affected_verts,
+                                   const eMeshFairingDepth depth)
 {
   /* Prefair. */
   UniformVertexWeight *uniform_vertex_weights = new UniformVertexWeight(fairing_context);
   UniformLoopWeight *uniform_loop_weights = new UniformLoopWeight();
-  fairing_context->fair_vertices(
-      affected_vertices, depth, uniform_vertex_weights, uniform_loop_weights);
+  fairing_context->fair_verts(affected_verts, depth, uniform_vertex_weights, uniform_loop_weights);
   delete uniform_vertex_weights;
 
   /* Fair. */
   VoronoiVertexWeight *voronoi_vertex_weights = new VoronoiVertexWeight(fairing_context);
   /* TODO: Implement cotangent loop weights. */
-  fairing_context->fair_vertices(
-      affected_vertices, depth, voronoi_vertex_weights, uniform_loop_weights);
+  fairing_context->fair_verts(affected_verts, depth, voronoi_vertex_weights, uniform_loop_weights);
 
   delete uniform_loop_weights;
   delete voronoi_vertex_weights;
 }
 
-void BKE_mesh_prefair_and_fair_vertices(struct Mesh *mesh,
-                                        struct MVert *deform_mverts,
-                                        bool *affect_vertices,
-                                        const eMeshFairingDepth depth)
+void BKE_mesh_prefair_and_fair_verts(struct Mesh *mesh,
+                                     struct MVert *deform_mverts,
+                                     bool *affect_verts,
+                                     const eMeshFairingDepth depth)
 {
   MeshFairingContext *fairing_context = new MeshFairingContext(mesh, deform_mverts);
-  prefair_and_fair_vertices(fairing_context, affect_vertices, depth);
+  prefair_and_fair_verts(fairing_context, affect_verts, depth);
   delete fairing_context;
 }
 
-void BKE_bmesh_prefair_and_fair_vertices(struct BMesh *bm,
-                                         bool *affect_vertices,
-                                         const eMeshFairingDepth depth)
+void BKE_bmesh_prefair_and_fair_verts(struct BMesh *bm,
+                                      bool *affect_verts,
+                                      const eMeshFairingDepth depth)
 {
   BMeshFairingContext *fairing_context = new BMeshFairingContext(bm);
-  prefair_and_fair_vertices(fairing_context, affect_vertices, depth);
+  prefair_and_fair_verts(fairing_context, affect_verts, depth);
   delete fairing_context;
 }
diff --git a/source/blender/blenkernel/intern/mesh_iterators.c b/source/blender/blenkernel/intern/mesh_iterators.c
index 77e62918441..d3a7f6cc72f 100644
--- a/source/blender/blenkernel/intern/mesh_iterators.c
+++ b/source/blender/blenkernel/intern/mesh_iterators.c
@@ -65,7 +65,7 @@ void BKE_mesh_foreach_mapped_vert(
     }
   }
   else {
-    const MVert *mv = mesh->mvert;
+    const MVert *mv = BKE_mesh_verts(mesh);
     const int *index = CustomData_get_layer(&mesh->vdata, CD_ORIGINDEX);
     const float(*vert_normals)[3] = (flag & MESH_FOREACH_USE_NORMAL) ?
                                         BKE_mesh_vertex_normals_ensure(mesh) :
@@ -120,8 +120,8 @@ void BKE_mesh_foreach_mapped_edge(
     }
   }
   else {
-    const MVert *mv = mesh->mvert;
-    const MEdge *med = mesh->medge;
+    const MVert *mv = BKE_mesh_verts(mesh);
+    const MEdge *med = BKE_mesh_edges(mesh);
     const int *index = CustomData_get_layer(&mesh->edata, CD_ORIGINDEX);
 
     if (index) {
@@ -188,9 +188,9 @@ void BKE_mesh_foreach_mapped_loop(Mesh *mesh,
                                  CustomData_get_layer(&mesh->ldata, CD_NORMAL) :
                                  NULL;
 
-    const MVert *mv = mesh->mvert;
-    const MLoop *ml = mesh->mloop;
-    const MPoly *mp = mesh->mpoly;
+    const MVert *mv = BKE_mesh_verts(mesh);
+    const MLoop *ml = BKE_mesh_loops(mesh);
+    const MPoly *mp = BKE_mesh_polys(mesh);
     const int *v_index = CustomData_get_layer(&mesh->vdata, CD_ORIGINDEX);
     const int *f_index = CustomData_get_layer(&mesh->pdata, CD_ORIGINDEX);
     int p_idx, i;
@@ -261,8 +261,9 @@ void BKE_mesh_foreach_mapped_face_center(
     }
   }
   else {
-    const MVert *mvert = mesh->mvert;
-    const MPoly *mp = mesh->mpoly;
+    const MVert *mvert = BKE_mesh_verts(mesh);
+    const MPoly *mp = BKE_mesh_polys(mesh);
+    const MLoop *loops = BKE_mesh_loops(mesh);
     const MLoop *ml;
     float _no_buf[3];
     float *no = (flag & MESH_FOREACH_USE_NORMAL) ? _no_buf : NULL;
@@ -275,7 +276,7 @@ void BKE_mesh_foreach_mapped_face_center(
           continue;
         }
         float cent[3];
-        ml = &mesh->mloop[mp->loopstart];
+        ml = &loops[mp->loopstart];
         BKE_mesh_calc_poly_center(mp, ml, mvert, cent);
         if (flag & MESH_FOREACH_USE_NORMAL) {
           BKE_mesh_calc_poly_normal(mp, ml, mvert, no);
@@ -286,7 +287,7 @@ void BKE_mesh_foreach_mapped_face_center(
     else {
       for (int i = 0; i < mesh->totpoly; i++, mp++) {
         float cent[3];
-        ml = &mesh->mloop[mp->loopstart];
+        ml = &loops[mp->loopstart];
         BKE_mesh_calc_poly_center(mp, ml, mvert, cent);
         if (flag & MESH_FOREACH_USE_NORMAL) {
           BKE_mesh_calc_poly_normal(mp, ml, mvert, no);
@@ -303,7 +304,9 @@ void BKE_mesh_foreach_mapped_subdiv_face_center(
     void *userData,
     MeshForeachFlag flag)
 {
-  const MPoly *mp = mesh->mpoly;
+  const MVert *verts = BKE_mesh_verts(mesh);
+  const MPoly *mp = BKE_mesh_polys(mesh);
+  const MLoop *loops = BKE_mesh_loops(mesh);
   const MLoop *ml;
   const MVert *mv;
   const float(*vert_normals)[3] = (flag & MESH_FOREACH_USE_NORMAL) ?
@@ -319,9 +322,9 @@ void BKE_mesh_foreach_mapped_subdiv_face_center(
       if (orig == ORIGINDEX_NONE) {
         continue;
       }
-      ml = &mesh->mloop[mp->loopstart];
+      ml = &loops[mp->loopstart];
       for (int j = 0; j < mp->totloop; j++, ml++) {
-        mv = &mesh->mvert[ml->v];
+        mv = &verts[ml->v];
         if (BLI_BITMAP_TEST(facedot_tags, ml->v)) {
           func(userData,
                orig,
@@ -333,9 +336,9 @@ void BKE_mesh_foreach_mapped_subdiv_face_center(
   }
   else {
     for (int i = 0; i < mesh->totpoly; i++, mp++) {
-      ml = &mesh->mloop[mp->loopstart];
+      ml = &loops[mp->loopstart];
       for (int j = 0; j < mp->totloop; j++, ml++) {
-        mv = &mesh->mvert[ml->v];
+        mv = &verts[ml->v];
         if (BLI_BITMAP_TEST(facedot_tags, ml->v)) {
           func(userData, i, mv->co, (flag & MESH_FOREACH_USE_NORMAL) ? vert_normals[ml->v] : NULL);
         }
diff --git a/source/blender/blenkernel/intern/mesh_legacy_convert.cc b/source/blender/blenkernel/intern/mesh_legacy_convert.cc
index 479dd6a012a..627c0057a28 100644
--- a/source/blender/blenkernel/intern/mesh_legacy_convert.cc
+++ b/source/blender/blenkernel/intern/mesh_legacy_convert.cc
@@ -7,7 +7,7 @@
  * Functions to convert mesh data to and from legacy formats like #MFace.
  */
 
-// #include 
+#define DNA_DEPRECATED_ALLOW
 
 #include "MEM_guardedalloc.h"
 
@@ -18,9 +18,12 @@
 #include "BLI_math.h"
 #include "BLI_memarena.h"
 #include "BLI_polyfill_2d.h"
+#include "BLI_task.hh"
 #include "BLI_utildefines.h"
 
+#include "BKE_attribute.hh"
 #include "BKE_customdata.h"
+#include "BKE_global.h"
 #include "BKE_mesh.h"
 #include "BKE_mesh_legacy_convert.h"
 #include "BKE_multires.h"
@@ -135,19 +138,19 @@ static void CustomData_to_bmeshpoly(CustomData *fdata, CustomData *ldata, int to
   for (int i = 0; i < fdata->totlayer; i++) {
     if (fdata->layers[i].type == CD_MTFACE) {
       CustomData_add_layer_named(
-          ldata, CD_MLOOPUV, CD_CALLOC, nullptr, totloop, fdata->layers[i].name);
+          ldata, CD_MLOOPUV, CD_SET_DEFAULT, nullptr, totloop, fdata->layers[i].name);
     }
     else if (fdata->layers[i].type == CD_MCOL) {
       CustomData_add_layer_named(
-          ldata, CD_PROP_BYTE_COLOR, CD_CALLOC, nullptr, totloop, fdata->layers[i].name);
+          ldata, CD_PROP_BYTE_COLOR, CD_SET_DEFAULT, nullptr, totloop, fdata->layers[i].name);
     }
     else if (fdata->layers[i].type == CD_MDISPS) {
       CustomData_add_layer_named(
-          ldata, CD_MDISPS, CD_CALLOC, nullptr, totloop, fdata->layers[i].name);
+          ldata, CD_MDISPS, CD_SET_DEFAULT, nullptr, totloop, fdata->layers[i].name);
     }
     else if (fdata->layers[i].type == CD_TESSLOOPNORMAL) {
       CustomData_add_layer_named(
-          ldata, CD_NORMAL, CD_CALLOC, nullptr, totloop, fdata->layers[i].name);
+          ldata, CD_NORMAL, CD_SET_DEFAULT, nullptr, totloop, fdata->layers[i].name);
     }
   }
 }
@@ -163,9 +166,7 @@ static void convert_mfaces_to_mpolys(ID *id,
                                      MEdge *medge,
                                      MFace *mface,
                                      int *r_totloop,
-                                     int *r_totpoly,
-                                     MLoop **r_mloop,
-                                     MPoly **r_mpoly)
+                                     int *r_totpoly)
 {
   MFace *mf;
   MLoop *ml, *mloop;
@@ -183,8 +184,13 @@ static void convert_mfaces_to_mpolys(ID *id,
   CustomData_free(pdata, totpoly_i);
 
   totpoly = totface_i;
-  mpoly = (MPoly *)MEM_calloc_arrayN((size_t)totpoly, sizeof(MPoly), "mpoly converted");
-  CustomData_add_layer(pdata, CD_MPOLY, CD_ASSIGN, mpoly, totpoly);
+  mpoly = (MPoly *)CustomData_add_layer(pdata, CD_MPOLY, CD_SET_DEFAULT, nullptr, totpoly);
+  int *material_indices = static_cast(
+      CustomData_get_layer_named(pdata, CD_PROP_INT32, "material_index"));
+  if (material_indices == nullptr) {
+    material_indices = static_cast(CustomData_add_layer_named(
+        pdata, CD_PROP_INT32, CD_SET_DEFAULT, nullptr, totpoly, "material_index"));
+  }
 
   numTex = CustomData_number_of_layers(fdata, CD_MTFACE);
   numCol = CustomData_number_of_layers(fdata, CD_MCOL);
@@ -195,9 +201,7 @@ static void convert_mfaces_to_mpolys(ID *id,
     totloop += mf->v4 ? 4 : 3;
   }
 
-  mloop = (MLoop *)MEM_calloc_arrayN((size_t)totloop, sizeof(MLoop), "mloop converted");
-
-  CustomData_add_layer(ldata, CD_MLOOP, CD_ASSIGN, mloop, totloop);
+  mloop = (MLoop *)CustomData_add_layer(ldata, CD_MLOOP, CD_SET_DEFAULT, nullptr, totloop);
 
   CustomData_to_bmeshpoly(fdata, ldata, totloop);
 
@@ -230,7 +234,7 @@ static void convert_mfaces_to_mpolys(ID *id,
 
     mp->totloop = mf->v4 ? 4 : 3;
 
-    mp->mat_nr = mf->mat_nr;
+    material_indices[i] = mf->mat_nr;
     mp->flag = mf->flag;
 
 #define ML(v1, v2) \
@@ -269,12 +273,51 @@ static void convert_mfaces_to_mpolys(ID *id,
 
   *r_totpoly = totpoly;
   *r_totloop = totloop;
-  *r_mpoly = mpoly;
-  *r_mloop = mloop;
 
 #undef ME_FGON
 }
 
+static void mesh_ensure_tessellation_customdata(Mesh *me)
+{
+  if (UNLIKELY((me->totface != 0) && (me->totpoly == 0))) {
+    /* Pass, otherwise this function  clears 'mface' before
+     * versioning 'mface -> mpoly' code kicks in T30583.
+     *
+     * Callers could also check but safer to do here - campbell */
+  }
+  else {
+    const int tottex_original = CustomData_number_of_layers(&me->ldata, CD_MLOOPUV);
+    const int totcol_original = CustomData_number_of_layers(&me->ldata, CD_PROP_BYTE_COLOR);
+
+    const int tottex_tessface = CustomData_number_of_layers(&me->fdata, CD_MTFACE);
+    const int totcol_tessface = CustomData_number_of_layers(&me->fdata, CD_MCOL);
+
+    if (tottex_tessface != tottex_original || totcol_tessface != totcol_original) {
+      BKE_mesh_tessface_clear(me);
+
+      BKE_mesh_add_mface_layers(&me->fdata, &me->ldata, me->totface);
+
+      /* TODO: add some `--debug-mesh` option. */
+      if (G.debug & G_DEBUG) {
+        /* NOTE(campbell): this warning may be un-called for if we are initializing the mesh for
+         * the first time from #BMesh, rather than giving a warning about this we could be smarter
+         * and check if there was any data to begin with, for now just print the warning with
+         * some info to help troubleshoot what's going on. */
+        printf(
+            "%s: warning! Tessellation uvs or vcol data got out of sync, "
+            "had to reset!\n    CD_MTFACE: %d != CD_MLOOPUV: %d || CD_MCOL: %d != "
+            "CD_PROP_BYTE_COLOR: "
+            "%d\n",
+            __func__,
+            tottex_tessface,
+            tottex_original,
+            totcol_tessface,
+            totcol_original);
+      }
+    }
+  }
+}
+
 void BKE_mesh_convert_mfaces_to_mpolys(Mesh *mesh)
 {
   convert_mfaces_to_mpolys(&mesh->id,
@@ -285,14 +328,12 @@ void BKE_mesh_convert_mfaces_to_mpolys(Mesh *mesh)
                            mesh->totface,
                            mesh->totloop,
                            mesh->totpoly,
-                           mesh->medge,
-                           mesh->mface,
+                           mesh->edges_for_write().data(),
+                           (MFace *)CustomData_get_layer(&mesh->fdata, CD_MFACE),
                            &mesh->totloop,
-                           &mesh->totpoly,
-                           &mesh->mloop,
-                           &mesh->mpoly);
+                           &mesh->totpoly);
 
-  BKE_mesh_update_customdata_pointers(mesh, true);
+  mesh_ensure_tessellation_customdata(mesh);
 }
 
 /**
@@ -344,16 +385,14 @@ void BKE_mesh_do_versions_convert_mfaces_to_mpolys(Mesh *mesh)
                            mesh->totface,
                            mesh->totloop,
                            mesh->totpoly,
-                           mesh->medge,
-                           mesh->mface,
+                           mesh->edges_for_write().data(),
+                           (MFace *)CustomData_get_layer(&mesh->fdata, CD_MFACE),
                            &mesh->totloop,
-                           &mesh->totpoly,
-                           &mesh->mloop,
-                           &mesh->mpoly);
+                           &mesh->totpoly);
 
   CustomData_bmesh_do_versions_update_active_layers(&mesh->fdata, &mesh->ldata);
 
-  BKE_mesh_update_customdata_pointers(mesh, true);
+  mesh_ensure_tessellation_customdata(mesh);
 }
 
 /** \} */
@@ -562,6 +601,8 @@ static int mesh_tessface_calc(CustomData *fdata,
 
   mpoly = (const MPoly *)CustomData_get_layer(pdata, CD_MPOLY);
   mloop = (const MLoop *)CustomData_get_layer(ldata, CD_MLOOP);
+  const int *material_indices = static_cast(
+      CustomData_get_layer_named(pdata, CD_PROP_INT32, "material_index"));
 
   /* Allocate the length of `totfaces`, avoid many small reallocation's,
    * if all faces are triangles it will be correct, `quads == 2x` allocations. */
@@ -600,7 +641,7 @@ static int mesh_tessface_calc(CustomData *fdata,
     lidx[1] = l2; \
     lidx[2] = l3; \
     lidx[3] = 0; \
-    mf->mat_nr = mp->mat_nr; \
+    mf->mat_nr = material_indices ? material_indices[poly_index] : 0; \
     mf->flag = mp->flag; \
     mf->edcode = 0; \
     (void)0
@@ -623,7 +664,7 @@ static int mesh_tessface_calc(CustomData *fdata,
     lidx[1] = l2; \
     lidx[2] = l3; \
     lidx[3] = l4; \
-    mf->mat_nr = mp->mat_nr; \
+    mf->mat_nr = material_indices ? material_indices[poly_index] : 0; \
     mf->flag = mp->flag; \
     mf->edcode = TESSFACE_IS_QUAD; \
     (void)0
@@ -709,7 +750,7 @@ static int mesh_tessface_calc(CustomData *fdata,
         lidx[2] = l3;
         lidx[3] = 0;
 
-        mf->mat_nr = mp->mat_nr;
+        mf->mat_nr = material_indices ? material_indices[poly_index] : 0;
         mf->flag = mp->flag;
         mf->edcode = 0;
 
@@ -783,12 +824,12 @@ void BKE_mesh_tessface_calc(Mesh *mesh)
   mesh->totface = mesh_tessface_calc(&mesh->fdata,
                                      &mesh->ldata,
                                      &mesh->pdata,
-                                     mesh->mvert,
+                                     BKE_mesh_verts_for_write(mesh),
                                      mesh->totface,
                                      mesh->totloop,
                                      mesh->totpoly);
 
-  BKE_mesh_update_customdata_pointers(mesh, true);
+  mesh_ensure_tessellation_customdata(mesh);
 }
 
 void BKE_mesh_tessface_ensure(struct Mesh *mesh)
@@ -847,26 +888,27 @@ void BKE_mesh_add_mface_layers(CustomData *fdata, CustomData *ldata, int total)
   for (int i = 0; i < ldata->totlayer; i++) {
     if (ldata->layers[i].type == CD_MLOOPUV) {
       CustomData_add_layer_named(
-          fdata, CD_MTFACE, CD_CALLOC, nullptr, total, ldata->layers[i].name);
+          fdata, CD_MTFACE, CD_SET_DEFAULT, nullptr, total, ldata->layers[i].name);
     }
     if (ldata->layers[i].type == CD_PROP_BYTE_COLOR) {
-      CustomData_add_layer_named(fdata, CD_MCOL, CD_CALLOC, nullptr, total, ldata->layers[i].name);
+      CustomData_add_layer_named(
+          fdata, CD_MCOL, CD_SET_DEFAULT, nullptr, total, ldata->layers[i].name);
     }
     else if (ldata->layers[i].type == CD_PREVIEW_MLOOPCOL) {
       CustomData_add_layer_named(
-          fdata, CD_PREVIEW_MCOL, CD_CALLOC, nullptr, total, ldata->layers[i].name);
+          fdata, CD_PREVIEW_MCOL, CD_SET_DEFAULT, nullptr, total, ldata->layers[i].name);
     }
     else if (ldata->layers[i].type == CD_ORIGSPACE_MLOOP) {
       CustomData_add_layer_named(
-          fdata, CD_ORIGSPACE, CD_CALLOC, nullptr, total, ldata->layers[i].name);
+          fdata, CD_ORIGSPACE, CD_SET_DEFAULT, nullptr, total, ldata->layers[i].name);
     }
     else if (ldata->layers[i].type == CD_NORMAL) {
       CustomData_add_layer_named(
-          fdata, CD_TESSLOOPNORMAL, CD_CALLOC, nullptr, total, ldata->layers[i].name);
+          fdata, CD_TESSLOOPNORMAL, CD_SET_DEFAULT, nullptr, total, ldata->layers[i].name);
     }
     else if (ldata->layers[i].type == CD_TANGENT) {
       CustomData_add_layer_named(
-          fdata, CD_TANGENT, CD_CALLOC, nullptr, total, ldata->layers[i].name);
+          fdata, CD_TANGENT, CD_SET_DEFAULT, nullptr, total, ldata->layers[i].name);
     }
   }
 
@@ -874,3 +916,189 @@ void BKE_mesh_add_mface_layers(CustomData *fdata, CustomData *ldata, int total)
 }
 
 /** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Bevel Weight Conversion
+ * \{ */
+
+void BKE_mesh_legacy_bevel_weight_from_layers(Mesh *mesh)
+{
+  using namespace blender;
+  MutableSpan verts = mesh->verts_for_write();
+  if (const float *weights = static_cast(
+          CustomData_get_layer(&mesh->vdata, CD_BWEIGHT))) {
+    mesh->cd_flag |= ME_CDFLAG_VERT_BWEIGHT;
+    for (const int i : verts.index_range()) {
+      verts[i].bweight_legacy = std::clamp(weights[i], 0.0f, 1.0f) * 255.0f;
+    }
+  }
+  else {
+    mesh->cd_flag &= ~ME_CDFLAG_VERT_BWEIGHT;
+    for (const int i : verts.index_range()) {
+      verts[i].bweight_legacy = 0;
+    }
+  }
+  MutableSpan edges = mesh->edges_for_write();
+  if (const float *weights = static_cast(
+          CustomData_get_layer(&mesh->edata, CD_BWEIGHT))) {
+    mesh->cd_flag |= ME_CDFLAG_EDGE_BWEIGHT;
+    for (const int i : edges.index_range()) {
+      edges[i].bweight_legacy = std::clamp(weights[i], 0.0f, 1.0f) * 255.0f;
+    }
+  }
+  else {
+    mesh->cd_flag &= ~ME_CDFLAG_EDGE_BWEIGHT;
+    for (const int i : edges.index_range()) {
+      edges[i].bweight_legacy = 0;
+    }
+  }
+}
+
+void BKE_mesh_legacy_bevel_weight_to_layers(Mesh *mesh)
+{
+  using namespace blender;
+  const Span verts = mesh->verts();
+  if (mesh->cd_flag & ME_CDFLAG_VERT_BWEIGHT) {
+    float *weights = static_cast(
+        CustomData_add_layer(&mesh->vdata, CD_BWEIGHT, CD_CONSTRUCT, nullptr, verts.size()));
+    for (const int i : verts.index_range()) {
+      weights[i] = verts[i].bweight_legacy / 255.0f;
+    }
+  }
+
+  const Span edges = mesh->edges();
+  if (mesh->cd_flag & ME_CDFLAG_EDGE_BWEIGHT) {
+    float *weights = static_cast(
+        CustomData_add_layer(&mesh->edata, CD_BWEIGHT, CD_CONSTRUCT, nullptr, edges.size()));
+    for (const int i : edges.index_range()) {
+      weights[i] = edges[i].bweight_legacy / 255.0f;
+    }
+  }
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Hide Attribute and Legacy Flag Conversion
+ * \{ */
+
+void BKE_mesh_legacy_convert_hide_layers_to_flags(Mesh *mesh)
+{
+  using namespace blender;
+  using namespace blender::bke;
+  const AttributeAccessor attributes = mesh->attributes();
+
+  MutableSpan verts = mesh->verts_for_write();
+  const VArray hide_vert = attributes.lookup_or_default(
+      ".hide_vert", ATTR_DOMAIN_POINT, false);
+  threading::parallel_for(verts.index_range(), 4096, [&](IndexRange range) {
+    for (const int i : range) {
+      SET_FLAG_FROM_TEST(verts[i].flag, hide_vert[i], ME_HIDE);
+    }
+  });
+
+  MutableSpan edges = mesh->edges_for_write();
+  const VArray hide_edge = attributes.lookup_or_default(
+      ".hide_edge", ATTR_DOMAIN_EDGE, false);
+  threading::parallel_for(edges.index_range(), 4096, [&](IndexRange range) {
+    for (const int i : range) {
+      SET_FLAG_FROM_TEST(edges[i].flag, hide_edge[i], ME_HIDE);
+    }
+  });
+
+  MutableSpan polys = mesh->polys_for_write();
+  const VArray hide_poly = attributes.lookup_or_default(
+      ".hide_poly", ATTR_DOMAIN_FACE, false);
+  threading::parallel_for(polys.index_range(), 4096, [&](IndexRange range) {
+    for (const int i : range) {
+      SET_FLAG_FROM_TEST(polys[i].flag, hide_poly[i], ME_HIDE);
+    }
+  });
+}
+
+void BKE_mesh_legacy_convert_flags_to_hide_layers(Mesh *mesh)
+{
+  using namespace blender;
+  using namespace blender::bke;
+  MutableAttributeAccessor attributes = mesh->attributes_for_write();
+
+  const Span verts = mesh->verts();
+  if (std::any_of(
+          verts.begin(), verts.end(), [](const MVert &vert) { return vert.flag & ME_HIDE; })) {
+    SpanAttributeWriter hide_vert = attributes.lookup_or_add_for_write_only_span(
+        ".hide_vert", ATTR_DOMAIN_POINT);
+    threading::parallel_for(verts.index_range(), 4096, [&](IndexRange range) {
+      for (const int i : range) {
+        hide_vert.span[i] = verts[i].flag & ME_HIDE;
+      }
+    });
+    hide_vert.finish();
+  }
+
+  const Span edges = mesh->edges();
+  if (std::any_of(
+          edges.begin(), edges.end(), [](const MEdge &edge) { return edge.flag & ME_HIDE; })) {
+    SpanAttributeWriter hide_edge = attributes.lookup_or_add_for_write_only_span(
+        ".hide_edge", ATTR_DOMAIN_EDGE);
+    threading::parallel_for(edges.index_range(), 4096, [&](IndexRange range) {
+      for (const int i : range) {
+        hide_edge.span[i] = edges[i].flag & ME_HIDE;
+      }
+    });
+    hide_edge.finish();
+  }
+
+  const Span polys = mesh->polys();
+  if (std::any_of(
+          polys.begin(), polys.end(), [](const MPoly &poly) { return poly.flag & ME_HIDE; })) {
+    SpanAttributeWriter hide_poly = attributes.lookup_or_add_for_write_only_span(
+        ".hide_poly", ATTR_DOMAIN_FACE);
+    threading::parallel_for(polys.index_range(), 4096, [&](IndexRange range) {
+      for (const int i : range) {
+        hide_poly.span[i] = polys[i].flag & ME_HIDE;
+      }
+    });
+    hide_poly.finish();
+  }
+}
+
+/** \} */
+/* -------------------------------------------------------------------- */
+/** \name Material Index Conversion
+ * \{ */
+
+void BKE_mesh_legacy_convert_material_indices_to_mpoly(Mesh *mesh)
+{
+  using namespace blender;
+  using namespace blender::bke;
+  const AttributeAccessor attributes = mesh->attributes();
+  MutableSpan polys = mesh->polys_for_write();
+  const VArray material_indices = attributes.lookup_or_default(
+      "material_index", ATTR_DOMAIN_FACE, 0);
+  threading::parallel_for(polys.index_range(), 4096, [&](IndexRange range) {
+    for (const int i : range) {
+      polys[i].mat_nr_legacy = material_indices[i];
+    }
+  });
+}
+
+void BKE_mesh_legacy_convert_mpoly_to_material_indices(Mesh *mesh)
+{
+  using namespace blender;
+  using namespace blender::bke;
+  MutableAttributeAccessor attributes = mesh->attributes_for_write();
+  const Span polys = mesh->polys();
+  if (std::any_of(
+          polys.begin(), polys.end(), [](const MPoly &poly) { return poly.mat_nr_legacy != 0; })) {
+    SpanAttributeWriter material_indices = attributes.lookup_or_add_for_write_only_span(
+        "material_index", ATTR_DOMAIN_FACE);
+    threading::parallel_for(polys.index_range(), 4096, [&](IndexRange range) {
+      for (const int i : range) {
+        material_indices.span[i] = polys[i].mat_nr_legacy;
+      }
+    });
+    material_indices.finish();
+  }
+}
+
+/** \} */
diff --git a/source/blender/blenkernel/intern/mesh_mapping.c b/source/blender/blenkernel/intern/mesh_mapping.c
deleted file mode 100644
index 9c4098e2db6..00000000000
--- a/source/blender/blenkernel/intern/mesh_mapping.c
+++ /dev/null
@@ -1,1158 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-
-/** \file
- * \ingroup bke
- *
- * Functions for accessing mesh connectivity data.
- * eg: polys connected to verts, UV's connected to verts.
- */
-
-#include "MEM_guardedalloc.h"
-
-#include "DNA_meshdata_types.h"
-#include "DNA_vec_types.h"
-
-#include "BLI_bitmap.h"
-#include "BLI_buffer.h"
-#include "BLI_math.h"
-#include "BLI_utildefines.h"
-
-#include "BKE_customdata.h"
-#include "BKE_mesh_mapping.h"
-#include "BLI_memarena.h"
-
-#include "BLI_strict_flags.h"
-
-/* -------------------------------------------------------------------- */
-/** \name Mesh Connectivity Mapping
- * \{ */
-
-/* ngon version wip, based on BM_uv_vert_map_create */
-UvVertMap *BKE_mesh_uv_vert_map_create(const MPoly *mpoly,
-                                       const MLoop *mloop,
-                                       const MLoopUV *mloopuv,
-                                       uint totpoly,
-                                       uint totvert,
-                                       const float limit[2],
-                                       const bool selected,
-                                       const bool use_winding)
-{
-  UvVertMap *vmap;
-  UvMapVert *buf;
-  const MPoly *mp;
-  uint a;
-  int i, totuv, nverts;
-
-  bool *winding = NULL;
-  BLI_buffer_declare_static(vec2f, tf_uv_buf, BLI_BUFFER_NOP, 32);
-
-  totuv = 0;
-
-  /* generate UvMapVert array */
-  mp = mpoly;
-  for (a = 0; a < totpoly; a++, mp++) {
-    if (!selected || (!(mp->flag & ME_HIDE) && (mp->flag & ME_FACE_SEL))) {
-      totuv += mp->totloop;
-    }
-  }
-
-  if (totuv == 0) {
-    return NULL;
-  }
-
-  vmap = (UvVertMap *)MEM_callocN(sizeof(*vmap), "UvVertMap");
-  buf = vmap->buf = (UvMapVert *)MEM_callocN(sizeof(*vmap->buf) * (size_t)totuv, "UvMapVert");
-  vmap->vert = (UvMapVert **)MEM_callocN(sizeof(*vmap->vert) * totvert, "UvMapVert*");
-  if (use_winding) {
-    winding = MEM_callocN(sizeof(*winding) * totpoly, "winding");
-  }
-
-  if (!vmap->vert || !vmap->buf) {
-    BKE_mesh_uv_vert_map_free(vmap);
-    return NULL;
-  }
-
-  mp = mpoly;
-  for (a = 0; a < totpoly; a++, mp++) {
-    if (!selected || (!(mp->flag & ME_HIDE) && (mp->flag & ME_FACE_SEL))) {
-      float(*tf_uv)[2] = NULL;
-
-      if (use_winding) {
-        tf_uv = (float(*)[2])BLI_buffer_reinit_data(&tf_uv_buf, vec2f, (size_t)mp->totloop);
-      }
-
-      nverts = mp->totloop;
-
-      for (i = 0; i < nverts; i++) {
-        buf->loop_of_poly_index = (unsigned short)i;
-        buf->poly_index = a;
-        buf->separate = 0;
-        buf->next = vmap->vert[mloop[mp->loopstart + i].v];
-        vmap->vert[mloop[mp->loopstart + i].v] = buf;
-
-        if (use_winding) {
-          copy_v2_v2(tf_uv[i], mloopuv[mpoly[a].loopstart + i].uv);
-        }
-
-        buf++;
-      }
-
-      if (use_winding) {
-        winding[a] = cross_poly_v2(tf_uv, (uint)nverts) > 0;
-      }
-    }
-  }
-
-  /* sort individual uvs for each vert */
-  for (a = 0; a < totvert; a++) {
-    UvMapVert *newvlist = NULL, *vlist = vmap->vert[a];
-    UvMapVert *iterv, *v, *lastv, *next;
-    const float *uv, *uv2;
-    float uvdiff[2];
-
-    while (vlist) {
-      v = vlist;
-      vlist = vlist->next;
-      v->next = newvlist;
-      newvlist = v;
-
-      uv = mloopuv[mpoly[v->poly_index].loopstart + v->loop_of_poly_index].uv;
-      lastv = NULL;
-      iterv = vlist;
-
-      while (iterv) {
-        next = iterv->next;
-
-        uv2 = mloopuv[mpoly[iterv->poly_index].loopstart + iterv->loop_of_poly_index].uv;
-        sub_v2_v2v2(uvdiff, uv2, uv);
-
-        if (fabsf(uv[0] - uv2[0]) < limit[0] && fabsf(uv[1] - uv2[1]) < limit[1] &&
-            (!use_winding || winding[iterv->poly_index] == winding[v->poly_index])) {
-          if (lastv) {
-            lastv->next = next;
-          }
-          else {
-            vlist = next;
-          }
-          iterv->next = newvlist;
-          newvlist = iterv;
-        }
-        else {
-          lastv = iterv;
-        }
-
-        iterv = next;
-      }
-
-      newvlist->separate = 1;
-    }
-
-    vmap->vert[a] = newvlist;
-  }
-
-  if (use_winding) {
-    MEM_freeN(winding);
-  }
-
-  BLI_buffer_free(&tf_uv_buf);
-
-  return vmap;
-}
-
-UvMapVert *BKE_mesh_uv_vert_map_get_vert(UvVertMap *vmap, uint v)
-{
-  return vmap->vert[v];
-}
-
-void BKE_mesh_uv_vert_map_free(UvVertMap *vmap)
-{
-  if (vmap) {
-    if (vmap->vert) {
-      MEM_freeN(vmap->vert);
-    }
-    if (vmap->buf) {
-      MEM_freeN(vmap->buf);
-    }
-    MEM_freeN(vmap);
-  }
-}
-
-/**
- * Generates a map where the key is the vertex and the value is a list
- * of polys or loops that use that vertex as a corner. The lists are allocated
- * from one memory pool.
- *
- * Wrapped by #BKE_mesh_vert_poly_map_create & BKE_mesh_vert_loop_map_create
- */
-static void mesh_vert_poly_or_loop_map_create(MeshElemMap **r_map,
-                                              int **r_mem,
-                                              const MPoly *mpoly,
-                                              const MLoop *mloop,
-                                              int totvert,
-                                              int totpoly,
-                                              int totloop,
-                                              const bool do_loops)
-{
-  MeshElemMap *map = MEM_callocN(sizeof(MeshElemMap) * (size_t)totvert, __func__);
-  int *indices, *index_iter;
-  int i, j;
-
-  indices = index_iter = MEM_mallocN(sizeof(int) * (size_t)totloop, __func__);
-
-  /* Count number of polys for each vertex */
-  for (i = 0; i < totpoly; i++) {
-    const MPoly *p = &mpoly[i];
-
-    for (j = 0; j < p->totloop; j++) {
-      map[mloop[p->loopstart + j].v].count++;
-    }
-  }
-
-  /* Assign indices mem */
-  for (i = 0; i < totvert; i++) {
-    map[i].indices = index_iter;
-    index_iter += map[i].count;
-
-    /* Reset 'count' for use as index in last loop */
-    map[i].count = 0;
-  }
-
-  /* Find the users */
-  for (i = 0; i < totpoly; i++) {
-    const MPoly *p = &mpoly[i];
-
-    for (j = 0; j < p->totloop; j++) {
-      uint v = mloop[p->loopstart + j].v;
-
-      map[v].indices[map[v].count] = do_loops ? p->loopstart + j : i;
-      map[v].count++;
-    }
-  }
-
-  *r_map = map;
-  *r_mem = indices;
-}
-
-void BKE_mesh_vert_poly_map_create(MeshElemMap **r_map,
-                                   int **r_mem,
-                                   const MPoly *mpoly,
-                                   const MLoop *mloop,
-                                   int totvert,
-                                   int totpoly,
-                                   int totloop)
-{
-  mesh_vert_poly_or_loop_map_create(r_map, r_mem, mpoly, mloop, totvert, totpoly, totloop, false);
-}
-
-void BKE_mesh_vert_loop_map_create(MeshElemMap **r_map,
-                                   int **r_mem,
-                                   const MPoly *mpoly,
-                                   const MLoop *mloop,
-                                   int totvert,
-                                   int totpoly,
-                                   int totloop)
-{
-  mesh_vert_poly_or_loop_map_create(r_map, r_mem, mpoly, mloop, totvert, totpoly, totloop, true);
-}
-
-void BKE_mesh_vert_looptri_map_create(MeshElemMap **r_map,
-                                      int **r_mem,
-                                      const MVert *UNUSED(mvert),
-                                      const int totvert,
-                                      const MLoopTri *mlooptri,
-                                      const int totlooptri,
-                                      const MLoop *mloop,
-                                      const int UNUSED(totloop))
-{
-  MeshElemMap *map = MEM_callocN(sizeof(MeshElemMap) * (size_t)totvert, __func__);
-  int *indices = MEM_mallocN(sizeof(int) * (size_t)totlooptri * 3, __func__);
-  int *index_step;
-  const MLoopTri *mlt;
-  int i;
-
-  /* count face users */
-  for (i = 0, mlt = mlooptri; i < totlooptri; mlt++, i++) {
-    for (int j = 3; j--;) {
-      map[mloop[mlt->tri[j]].v].count++;
-    }
-  }
-
-  /* create offsets */
-  index_step = indices;
-  for (i = 0; i < totvert; i++) {
-    map[i].indices = index_step;
-    index_step += map[i].count;
-
-    /* re-count, using this as an index below */
-    map[i].count = 0;
-  }
-
-  /* assign looptri-edge users */
-  for (i = 0, mlt = mlooptri; i < totlooptri; mlt++, i++) {
-    for (int j = 3; j--;) {
-      MeshElemMap *map_ele = &map[mloop[mlt->tri[j]].v];
-      map_ele->indices[map_ele->count++] = i;
-    }
-  }
-
-  *r_map = map;
-  *r_mem = indices;
-}
-
-void BKE_mesh_vert_edge_map_create(
-    MeshElemMap **r_map, int **r_mem, const MEdge *medge, int totvert, int totedge)
-{
-  MeshElemMap *map = MEM_callocN(sizeof(MeshElemMap) * (size_t)totvert, "vert-edge map");
-  int *indices = MEM_mallocN(sizeof(int[2]) * (size_t)totedge, "vert-edge map mem");
-  int *i_pt = indices;
-
-  int i;
-
-  /* Count number of edges for each vertex */
-  for (i = 0; i < totedge; i++) {
-    map[medge[i].v1].count++;
-    map[medge[i].v2].count++;
-  }
-
-  /* Assign indices mem */
-  for (i = 0; i < totvert; i++) {
-    map[i].indices = i_pt;
-    i_pt += map[i].count;
-
-    /* Reset 'count' for use as index in last loop */
-    map[i].count = 0;
-  }
-
-  /* Find the users */
-  for (i = 0; i < totedge; i++) {
-    const uint v[2] = {medge[i].v1, medge[i].v2};
-
-    map[v[0]].indices[map[v[0]].count] = i;
-    map[v[1]].indices[map[v[1]].count] = i;
-
-    map[v[0]].count++;
-    map[v[1]].count++;
-  }
-
-  *r_map = map;
-  *r_mem = indices;
-}
-
-void BKE_mesh_vert_edge_vert_map_create(
-    MeshElemMap **r_map, int **r_mem, const MEdge *medge, int totvert, int totedge)
-{
-  MeshElemMap *map = MEM_callocN(sizeof(MeshElemMap) * (size_t)totvert, "vert-edge map");
-  int *indices = MEM_mallocN(sizeof(int[2]) * (size_t)totedge, "vert-edge map mem");
-  int *i_pt = indices;
-
-  int i;
-
-  /* Count number of edges for each vertex */
-  for (i = 0; i < totedge; i++) {
-    map[medge[i].v1].count++;
-    map[medge[i].v2].count++;
-  }
-
-  /* Assign indices mem */
-  for (i = 0; i < totvert; i++) {
-    map[i].indices = i_pt;
-    i_pt += map[i].count;
-
-    /* Reset 'count' for use as index in last loop */
-    map[i].count = 0;
-  }
-
-  /* Find the users */
-  for (i = 0; i < totedge; i++) {
-    const uint v[2] = {medge[i].v1, medge[i].v2};
-
-    map[v[0]].indices[map[v[0]].count] = (int)v[1];
-    map[v[1]].indices[map[v[1]].count] = (int)v[0];
-
-    map[v[0]].count++;
-    map[v[1]].count++;
-  }
-
-  *r_map = map;
-  *r_mem = indices;
-}
-
-void BKE_mesh_edge_loop_map_create(MeshElemMap **r_map,
-                                   int **r_mem,
-                                   const MEdge *UNUSED(medge),
-                                   const int totedge,
-                                   const MPoly *mpoly,
-                                   const int totpoly,
-                                   const MLoop *mloop,
-                                   const int totloop)
-{
-  MeshElemMap *map = MEM_callocN(sizeof(MeshElemMap) * (size_t)totedge, "edge-poly map");
-  int *indices = MEM_mallocN(sizeof(int) * (size_t)totloop * 2, "edge-poly map mem");
-  int *index_step;
-  const MPoly *mp;
-  int i;
-
-  /* count face users */
-  for (i = 0, mp = mpoly; i < totpoly; mp++, i++) {
-    const MLoop *ml;
-    int j = mp->totloop;
-    for (ml = &mloop[mp->loopstart]; j--; ml++) {
-      map[ml->e].count += 2;
-    }
-  }
-
-  /* create offsets */
-  index_step = indices;
-  for (i = 0; i < totedge; i++) {
-    map[i].indices = index_step;
-    index_step += map[i].count;
-
-    /* re-count, using this as an index below */
-    map[i].count = 0;
-  }
-
-  /* assign loop-edge users */
-  for (i = 0, mp = mpoly; i < totpoly; mp++, i++) {
-    const MLoop *ml;
-    MeshElemMap *map_ele;
-    const int max_loop = mp->loopstart + mp->totloop;
-    int j = mp->loopstart;
-    for (ml = &mloop[j]; j < max_loop; j++, ml++) {
-      map_ele = &map[ml->e];
-      map_ele->indices[map_ele->count++] = j;
-      map_ele->indices[map_ele->count++] = j + 1;
-    }
-    /* last edge/loop of poly, must point back to first loop! */
-    map_ele->indices[map_ele->count - 1] = mp->loopstart;
-  }
-
-  *r_map = map;
-  *r_mem = indices;
-}
-
-void BKE_mesh_edge_poly_map_create(MeshElemMap **r_map,
-                                   int **r_mem,
-                                   const MEdge *UNUSED(medge),
-                                   const int totedge,
-                                   const MPoly *mpoly,
-                                   const int totpoly,
-                                   const MLoop *mloop,
-                                   const int totloop)
-{
-  MeshElemMap *map = MEM_callocN(sizeof(MeshElemMap) * (size_t)totedge, "edge-poly map");
-  int *indices = MEM_mallocN(sizeof(int) * (size_t)totloop, "edge-poly map mem");
-  int *index_step;
-  const MPoly *mp;
-  int i;
-
-  /* count face users */
-  for (i = 0, mp = mpoly; i < totpoly; mp++, i++) {
-    const MLoop *ml;
-    int j = mp->totloop;
-    for (ml = &mloop[mp->loopstart]; j--; ml++) {
-      map[ml->e].count++;
-    }
-  }
-
-  /* create offsets */
-  index_step = indices;
-  for (i = 0; i < totedge; i++) {
-    map[i].indices = index_step;
-    index_step += map[i].count;
-
-    /* re-count, using this as an index below */
-    map[i].count = 0;
-  }
-
-  /* assign poly-edge users */
-  for (i = 0, mp = mpoly; i < totpoly; mp++, i++) {
-    const MLoop *ml;
-    int j = mp->totloop;
-    for (ml = &mloop[mp->loopstart]; j--; ml++) {
-      MeshElemMap *map_ele = &map[ml->e];
-      map_ele->indices[map_ele->count++] = i;
-    }
-  }
-
-  *r_map = map;
-  *r_mem = indices;
-}
-
-void BKE_mesh_origindex_map_create(MeshElemMap **r_map,
-                                   int **r_mem,
-                                   const int totsource,
-                                   const int *final_origindex,
-                                   const int totfinal)
-{
-  MeshElemMap *map = MEM_callocN(sizeof(MeshElemMap) * (size_t)totsource, "poly-tessface map");
-  int *indices = MEM_mallocN(sizeof(int) * (size_t)totfinal, "poly-tessface map mem");
-  int *index_step;
-  int i;
-
-  /* count face users */
-  for (i = 0; i < totfinal; i++) {
-    if (final_origindex[i] != ORIGINDEX_NONE) {
-      BLI_assert(final_origindex[i] < totsource);
-      map[final_origindex[i]].count++;
-    }
-  }
-
-  /* create offsets */
-  index_step = indices;
-  for (i = 0; i < totsource; i++) {
-    map[i].indices = index_step;
-    index_step += map[i].count;
-
-    /* re-count, using this as an index below */
-    map[i].count = 0;
-  }
-
-  /* assign poly-tessface users */
-  for (i = 0; i < totfinal; i++) {
-    if (final_origindex[i] != ORIGINDEX_NONE) {
-      MeshElemMap *map_ele = &map[final_origindex[i]];
-      map_ele->indices[map_ele->count++] = i;
-    }
-  }
-
-  *r_map = map;
-  *r_mem = indices;
-}
-
-void BKE_mesh_origindex_map_create_looptri(MeshElemMap **r_map,
-                                           int **r_mem,
-                                           const MPoly *mpoly,
-                                           const int mpoly_num,
-                                           const MLoopTri *looptri,
-                                           const int looptri_num)
-{
-  MeshElemMap *map = MEM_callocN(sizeof(MeshElemMap) * (size_t)mpoly_num, "poly-tessface map");
-  int *indices = MEM_mallocN(sizeof(int) * (size_t)looptri_num, "poly-tessface map mem");
-  int *index_step;
-  int i;
-
-  /* create offsets */
-  index_step = indices;
-  for (i = 0; i < mpoly_num; i++) {
-    map[i].indices = index_step;
-    index_step += ME_POLY_TRI_TOT(&mpoly[i]);
-  }
-
-  /* assign poly-tessface users */
-  for (i = 0; i < looptri_num; i++) {
-    MeshElemMap *map_ele = &map[looptri[i].poly];
-    map_ele->indices[map_ele->count++] = i;
-  }
-
-  *r_map = map;
-  *r_mem = indices;
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Mesh loops/poly islands.
- * Used currently for UVs and 'smooth groups'.
- * \{ */
-
-/**
- * Callback deciding whether the given poly/loop/edge define an island boundary or not.
- */
-typedef bool (*MeshRemap_CheckIslandBoundary)(const struct MPoly *mpoly,
-                                              const struct MLoop *mloop,
-                                              const struct MEdge *medge,
-                                              const int edge_user_count,
-                                              const struct MPoly *mpoly_array,
-                                              const struct MeshElemMap *edge_poly_map,
-                                              void *user_data);
-
-static void poly_edge_loop_islands_calc(const MEdge *medge,
-                                        const int totedge,
-                                        const MPoly *mpoly,
-                                        const int totpoly,
-                                        const MLoop *mloop,
-                                        const int totloop,
-                                        MeshElemMap *edge_poly_map,
-                                        const bool use_bitflags,
-                                        MeshRemap_CheckIslandBoundary edge_boundary_check,
-                                        void *edge_boundary_check_data,
-                                        int **r_poly_groups,
-                                        int *r_totgroup,
-                                        BLI_bitmap **r_edge_borders,
-                                        int *r_totedgeborder)
-{
-  int *poly_groups;
-  int *poly_stack;
-
-  BLI_bitmap *edge_borders = NULL;
-  int num_edgeborders = 0;
-
-  int poly_prev = 0;
-  const int temp_poly_group_id = 3; /* Placeholder value. */
-
-  /* Group we could not find any available bit, will be reset to 0 at end. */
-  const int poly_group_id_overflowed = 5;
-
-  int tot_group = 0;
-  bool group_id_overflow = false;
-
-  /* map vars */
-  int *edge_poly_mem = NULL;
-
-  if (totpoly == 0) {
-    *r_totgroup = 0;
-    *r_poly_groups = NULL;
-    if (r_edge_borders) {
-      *r_edge_borders = NULL;
-      *r_totedgeborder = 0;
-    }
-    return;
-  }
-
-  if (r_edge_borders) {
-    edge_borders = BLI_BITMAP_NEW(totedge, __func__);
-    *r_totedgeborder = 0;
-  }
-
-  if (!edge_poly_map) {
-    BKE_mesh_edge_poly_map_create(
-        &edge_poly_map, &edge_poly_mem, medge, totedge, mpoly, totpoly, mloop, totloop);
-  }
-
-  poly_groups = MEM_callocN(sizeof(int) * (size_t)totpoly, __func__);
-  poly_stack = MEM_mallocN(sizeof(int) * (size_t)totpoly, __func__);
-
-  while (true) {
-    int poly;
-    int bit_poly_group_mask = 0;
-    int poly_group_id;
-    int ps_curr_idx = 0, ps_end_idx = 0; /* stack indices */
-
-    for (poly = poly_prev; poly < totpoly; poly++) {
-      if (poly_groups[poly] == 0) {
-        break;
-      }
-    }
-
-    if (poly == totpoly) {
-      /* all done */
-      break;
-    }
-
-    poly_group_id = use_bitflags ? temp_poly_group_id : ++tot_group;
-
-    /* start searching from here next time */
-    poly_prev = poly + 1;
-
-    poly_groups[poly] = poly_group_id;
-    poly_stack[ps_end_idx++] = poly;
-
-    while (ps_curr_idx != ps_end_idx) {
-      const MPoly *mp;
-      const MLoop *ml;
-      int j;
-
-      poly = poly_stack[ps_curr_idx++];
-      BLI_assert(poly_groups[poly] == poly_group_id);
-
-      mp = &mpoly[poly];
-      for (ml = &mloop[mp->loopstart], j = mp->totloop; j--; ml++) {
-        /* loop over poly users */
-        const int me_idx = (int)ml->e;
-        const MEdge *me = &medge[me_idx];
-        const MeshElemMap *map_ele = &edge_poly_map[me_idx];
-        const int *p = map_ele->indices;
-        int i = map_ele->count;
-        if (!edge_boundary_check(mp, ml, me, i, mpoly, map_ele, edge_boundary_check_data)) {
-          for (; i--; p++) {
-            /* if we meet other non initialized its a bug */
-            BLI_assert(ELEM(poly_groups[*p], 0, poly_group_id));
-
-            if (poly_groups[*p] == 0) {
-              poly_groups[*p] = poly_group_id;
-              poly_stack[ps_end_idx++] = *p;
-            }
-          }
-        }
-        else {
-          if (edge_borders && !BLI_BITMAP_TEST(edge_borders, me_idx)) {
-            BLI_BITMAP_ENABLE(edge_borders, me_idx);
-            num_edgeborders++;
-          }
-          if (use_bitflags) {
-            /* Find contiguous smooth groups already assigned,
-             * these are the values we can't reuse! */
-            for (; i--; p++) {
-              int bit = poly_groups[*p];
-              if (!ELEM(bit, 0, poly_group_id, poly_group_id_overflowed) &&
-                  !(bit_poly_group_mask & bit)) {
-                bit_poly_group_mask |= bit;
-              }
-            }
-          }
-        }
-      }
-    }
-    /* And now, we have all our poly from current group in poly_stack
-     * (from 0 to (ps_end_idx - 1)),
-     * as well as all smoothgroups bits we can't use in bit_poly_group_mask.
-     */
-    if (use_bitflags) {
-      int i, *p, gid_bit = 0;
-      poly_group_id = 1;
-
-      /* Find first bit available! */
-      for (; (poly_group_id & bit_poly_group_mask) && (gid_bit < 32); gid_bit++) {
-        poly_group_id <<= 1; /* will 'overflow' on last possible iteration. */
-      }
-      if (UNLIKELY(gid_bit > 31)) {
-        /* All bits used in contiguous smooth groups, we can't do much!
-         * NOTE: this is *very* unlikely - theoretically, four groups are enough,
-         *       I don't think we can reach this goal with such a simple algorithm,
-         *       but I don't think either we'll never need all 32 groups!
-         */
-        printf(
-            "Warning, could not find an available id for current smooth group, faces will me "
-            "marked "
-            "as out of any smooth group...\n");
-
-        /* Can't use 0, will have to set them to this value later. */
-        poly_group_id = poly_group_id_overflowed;
-
-        group_id_overflow = true;
-      }
-      if (gid_bit > tot_group) {
-        tot_group = gid_bit;
-      }
-      /* And assign the final smooth group id to that poly group! */
-      for (i = ps_end_idx, p = poly_stack; i--; p++) {
-        poly_groups[*p] = poly_group_id;
-      }
-    }
-  }
-
-  if (use_bitflags) {
-    /* used bits are zero-based. */
-    tot_group++;
-  }
-
-  if (UNLIKELY(group_id_overflow)) {
-    int i = totpoly, *gid = poly_groups;
-    for (; i--; gid++) {
-      if (*gid == poly_group_id_overflowed) {
-        *gid = 0;
-      }
-    }
-    /* Using 0 as group id adds one more group! */
-    tot_group++;
-  }
-
-  if (edge_poly_mem) {
-    MEM_freeN(edge_poly_map);
-    MEM_freeN(edge_poly_mem);
-  }
-  MEM_freeN(poly_stack);
-
-  *r_totgroup = tot_group;
-  *r_poly_groups = poly_groups;
-  if (r_edge_borders) {
-    *r_edge_borders = edge_borders;
-    *r_totedgeborder = num_edgeborders;
-  }
-}
-
-static bool poly_is_island_boundary_smooth_cb(const MPoly *mp,
-                                              const MLoop *UNUSED(ml),
-                                              const MEdge *me,
-                                              const int edge_user_count,
-                                              const MPoly *mpoly_array,
-                                              const MeshElemMap *edge_poly_map,
-                                              void *UNUSED(user_data))
-{
-  /* Edge is sharp if one of its polys is flat, or edge itself is sharp,
-   * or edge is not used by exactly two polygons. */
-  if ((mp->flag & ME_SMOOTH) && !(me->flag & ME_SHARP) && (edge_user_count == 2)) {
-    /* In that case, edge appears to be smooth, but we need to check its other poly too. */
-    const MPoly *mp_other = (mp == &mpoly_array[edge_poly_map->indices[0]]) ?
-                                &mpoly_array[edge_poly_map->indices[1]] :
-                                &mpoly_array[edge_poly_map->indices[0]];
-    return (mp_other->flag & ME_SMOOTH) == 0;
-  }
-  return true;
-}
-
-int *BKE_mesh_calc_smoothgroups(const MEdge *medge,
-                                const int totedge,
-                                const MPoly *mpoly,
-                                const int totpoly,
-                                const MLoop *mloop,
-                                const int totloop,
-                                int *r_totgroup,
-                                const bool use_bitflags)
-{
-  int *poly_groups = NULL;
-
-  poly_edge_loop_islands_calc(medge,
-                              totedge,
-                              mpoly,
-                              totpoly,
-                              mloop,
-                              totloop,
-                              NULL,
-                              use_bitflags,
-                              poly_is_island_boundary_smooth_cb,
-                              NULL,
-                              &poly_groups,
-                              r_totgroup,
-                              NULL,
-                              NULL);
-
-  return poly_groups;
-}
-
-#define MISLAND_DEFAULT_BUFSIZE 64
-
-void BKE_mesh_loop_islands_init(MeshIslandStore *island_store,
-                                const short item_type,
-                                const int items_num,
-                                const short island_type,
-                                const short innercut_type)
-{
-  MemArena *mem = island_store->mem;
-
-  if (mem == NULL) {
-    mem = BLI_memarena_new(BLI_MEMARENA_STD_BUFSIZE, __func__);
-    island_store->mem = mem;
-  }
-  /* else memarena should be cleared */
-
-  BLI_assert(
-      ELEM(item_type, MISLAND_TYPE_VERT, MISLAND_TYPE_EDGE, MISLAND_TYPE_POLY, MISLAND_TYPE_LOOP));
-  BLI_assert(ELEM(
-      island_type, MISLAND_TYPE_VERT, MISLAND_TYPE_EDGE, MISLAND_TYPE_POLY, MISLAND_TYPE_LOOP));
-
-  island_store->item_type = item_type;
-  island_store->items_to_islands_num = items_num;
-  island_store->items_to_islands = BLI_memarena_alloc(
-      mem, sizeof(*island_store->items_to_islands) * (size_t)items_num);
-
-  island_store->island_type = island_type;
-  island_store->islands_num_alloc = MISLAND_DEFAULT_BUFSIZE;
-  island_store->islands = BLI_memarena_alloc(
-      mem, sizeof(*island_store->islands) * island_store->islands_num_alloc);
-
-  island_store->innercut_type = innercut_type;
-  island_store->innercuts = BLI_memarena_alloc(
-      mem, sizeof(*island_store->innercuts) * island_store->islands_num_alloc);
-}
-
-void BKE_mesh_loop_islands_clear(MeshIslandStore *island_store)
-{
-  island_store->item_type = MISLAND_TYPE_NONE;
-  island_store->items_to_islands_num = 0;
-  island_store->items_to_islands = NULL;
-
-  island_store->island_type = MISLAND_TYPE_NONE;
-  island_store->islands_num = 0;
-  island_store->islands = NULL;
-
-  island_store->innercut_type = MISLAND_TYPE_NONE;
-  island_store->innercuts = NULL;
-
-  if (island_store->mem) {
-    BLI_memarena_clear(island_store->mem);
-  }
-
-  island_store->islands_num_alloc = 0;
-}
-
-void BKE_mesh_loop_islands_free(MeshIslandStore *island_store)
-{
-  if (island_store->mem) {
-    BLI_memarena_free(island_store->mem);
-    island_store->mem = NULL;
-  }
-}
-
-void BKE_mesh_loop_islands_add(MeshIslandStore *island_store,
-                               const int item_num,
-                               const int *items_indices,
-                               const int num_island_items,
-                               int *island_item_indices,
-                               const int num_innercut_items,
-                               int *innercut_item_indices)
-{
-  MemArena *mem = island_store->mem;
-
-  MeshElemMap *isld, *innrcut;
-  const int curr_island_idx = island_store->islands_num++;
-  const size_t curr_num_islands = (size_t)island_store->islands_num;
-  int i = item_num;
-
-  while (i--) {
-    island_store->items_to_islands[items_indices[i]] = curr_island_idx;
-  }
-
-  if (UNLIKELY(curr_num_islands > island_store->islands_num_alloc)) {
-    MeshElemMap **islds, **innrcuts;
-
-    island_store->islands_num_alloc *= 2;
-    islds = BLI_memarena_alloc(mem, sizeof(*islds) * island_store->islands_num_alloc);
-    memcpy(islds, island_store->islands, sizeof(*islds) * (curr_num_islands - 1));
-    island_store->islands = islds;
-
-    innrcuts = BLI_memarena_alloc(mem, sizeof(*innrcuts) * island_store->islands_num_alloc);
-    memcpy(innrcuts, island_store->innercuts, sizeof(*innrcuts) * (curr_num_islands - 1));
-    island_store->innercuts = innrcuts;
-  }
-
-  island_store->islands[curr_island_idx] = isld = BLI_memarena_alloc(mem, sizeof(*isld));
-  isld->count = num_island_items;
-  isld->indices = BLI_memarena_alloc(mem, sizeof(*isld->indices) * (size_t)num_island_items);
-  memcpy(isld->indices, island_item_indices, sizeof(*isld->indices) * (size_t)num_island_items);
-
-  island_store->innercuts[curr_island_idx] = innrcut = BLI_memarena_alloc(mem, sizeof(*innrcut));
-  innrcut->count = num_innercut_items;
-  innrcut->indices = BLI_memarena_alloc(mem,
-                                        sizeof(*innrcut->indices) * (size_t)num_innercut_items);
-  memcpy(innrcut->indices,
-         innercut_item_indices,
-         sizeof(*innrcut->indices) * (size_t)num_innercut_items);
-}
-
-/* TODO: I'm not sure edge seam flag is enough to define UV islands?
- *       Maybe we should also consider UV-maps values
- *       themselves (i.e. different UV-edges for a same mesh-edge => boundary edge too?).
- *       Would make things much more complex though,
- *       and each UVMap would then need its own mesh mapping, not sure we want that at all!
- */
-typedef struct MeshCheckIslandBoundaryUv {
-  const MLoop *loops;
-  const MLoopUV *luvs;
-  const MeshElemMap *edge_loop_map;
-} MeshCheckIslandBoundaryUv;
-
-static bool mesh_check_island_boundary_uv(const MPoly *UNUSED(mp),
-                                          const MLoop *ml,
-                                          const MEdge *me,
-                                          const int UNUSED(edge_user_count),
-                                          const MPoly *UNUSED(mpoly_array),
-                                          const MeshElemMap *UNUSED(edge_poly_map),
-                                          void *user_data)
-{
-  if (user_data) {
-    const MeshCheckIslandBoundaryUv *data = user_data;
-    const MLoop *loops = data->loops;
-    const MLoopUV *luvs = data->luvs;
-    const MeshElemMap *edge_to_loops = &data->edge_loop_map[ml->e];
-
-    BLI_assert(edge_to_loops->count >= 2 && (edge_to_loops->count % 2) == 0);
-
-    const uint v1 = loops[edge_to_loops->indices[0]].v;
-    const uint v2 = loops[edge_to_loops->indices[1]].v;
-    const float *uvco_v1 = luvs[edge_to_loops->indices[0]].uv;
-    const float *uvco_v2 = luvs[edge_to_loops->indices[1]].uv;
-    for (int i = 2; i < edge_to_loops->count; i += 2) {
-      if (loops[edge_to_loops->indices[i]].v == v1) {
-        if (!equals_v2v2(uvco_v1, luvs[edge_to_loops->indices[i]].uv) ||
-            !equals_v2v2(uvco_v2, luvs[edge_to_loops->indices[i + 1]].uv)) {
-          return true;
-        }
-      }
-      else {
-        BLI_assert(loops[edge_to_loops->indices[i]].v == v2);
-        UNUSED_VARS_NDEBUG(v2);
-        if (!equals_v2v2(uvco_v2, luvs[edge_to_loops->indices[i]].uv) ||
-            !equals_v2v2(uvco_v1, luvs[edge_to_loops->indices[i + 1]].uv)) {
-          return true;
-        }
-      }
-    }
-    return false;
-  }
-
-  /* Edge is UV boundary if tagged as seam. */
-  return (me->flag & ME_SEAM) != 0;
-}
-
-static bool mesh_calc_islands_loop_poly_uv(MVert *UNUSED(verts),
-                                           const int UNUSED(totvert),
-                                           MEdge *edges,
-                                           const int totedge,
-                                           MPoly *polys,
-                                           const int totpoly,
-                                           MLoop *loops,
-                                           const int totloop,
-                                           const MLoopUV *luvs,
-                                           MeshIslandStore *r_island_store)
-{
-  int *poly_groups = NULL;
-  int num_poly_groups;
-
-  /* map vars */
-  MeshElemMap *edge_poly_map;
-  int *edge_poly_mem;
-
-  MeshElemMap *edge_loop_map;
-  int *edge_loop_mem;
-
-  MeshCheckIslandBoundaryUv edge_boundary_check_data;
-
-  int *poly_indices;
-  int *loop_indices;
-  int num_pidx, num_lidx;
-
-  /* Those are used to detect 'inner cuts', i.e. edges that are borders,
-   * and yet have two or more polys of a same group using them
-   * (typical case: seam used to unwrap properly a cylinder). */
-  BLI_bitmap *edge_borders = NULL;
-  int num_edge_borders = 0;
-  char *edge_border_count = NULL;
-  int *edge_innercut_indices = NULL;
-  int num_einnercuts = 0;
-
-  int grp_idx, p_idx, pl_idx, l_idx;
-
-  BKE_mesh_loop_islands_clear(r_island_store);
-  BKE_mesh_loop_islands_init(
-      r_island_store, MISLAND_TYPE_LOOP, totloop, MISLAND_TYPE_POLY, MISLAND_TYPE_EDGE);
-
-  BKE_mesh_edge_poly_map_create(
-      &edge_poly_map, &edge_poly_mem, edges, totedge, polys, totpoly, loops, totloop);
-
-  if (luvs) {
-    BKE_mesh_edge_loop_map_create(
-        &edge_loop_map, &edge_loop_mem, edges, totedge, polys, totpoly, loops, totloop);
-    edge_boundary_check_data.loops = loops;
-    edge_boundary_check_data.luvs = luvs;
-    edge_boundary_check_data.edge_loop_map = edge_loop_map;
-  }
-
-  poly_edge_loop_islands_calc(edges,
-                              totedge,
-                              polys,
-                              totpoly,
-                              loops,
-                              totloop,
-                              edge_poly_map,
-                              false,
-                              mesh_check_island_boundary_uv,
-                              luvs ? &edge_boundary_check_data : NULL,
-                              &poly_groups,
-                              &num_poly_groups,
-                              &edge_borders,
-                              &num_edge_borders);
-
-  if (!num_poly_groups) {
-    /* Should never happen... */
-    MEM_freeN(edge_poly_map);
-    MEM_freeN(edge_poly_mem);
-
-    if (edge_borders) {
-      MEM_freeN(edge_borders);
-    }
-    return false;
-  }
-
-  if (num_edge_borders) {
-    edge_border_count = MEM_mallocN(sizeof(*edge_border_count) * (size_t)totedge, __func__);
-    edge_innercut_indices = MEM_mallocN(sizeof(*edge_innercut_indices) * (size_t)num_edge_borders,
-                                        __func__);
-  }
-
-  poly_indices = MEM_mallocN(sizeof(*poly_indices) * (size_t)totpoly, __func__);
-  loop_indices = MEM_mallocN(sizeof(*loop_indices) * (size_t)totloop, __func__);
-
-  /* NOTE: here we ignore '0' invalid group - this should *never* happen in this case anyway? */
-  for (grp_idx = 1; grp_idx <= num_poly_groups; grp_idx++) {
-    num_pidx = num_lidx = 0;
-    if (num_edge_borders) {
-      num_einnercuts = 0;
-      memset(edge_border_count, 0, sizeof(*edge_border_count) * (size_t)totedge);
-    }
-
-    for (p_idx = 0; p_idx < totpoly; p_idx++) {
-      MPoly *mp;
-
-      if (poly_groups[p_idx] != grp_idx) {
-        continue;
-      }
-
-      mp = &polys[p_idx];
-      poly_indices[num_pidx++] = p_idx;
-      for (l_idx = mp->loopstart, pl_idx = 0; pl_idx < mp->totloop; l_idx++, pl_idx++) {
-        MLoop *ml = &loops[l_idx];
-        loop_indices[num_lidx++] = l_idx;
-        if (num_edge_borders && BLI_BITMAP_TEST(edge_borders, ml->e) &&
-            (edge_border_count[ml->e] < 2)) {
-          edge_border_count[ml->e]++;
-          if (edge_border_count[ml->e] == 2) {
-            edge_innercut_indices[num_einnercuts++] = (int)ml->e;
-          }
-        }
-      }
-    }
-
-    BKE_mesh_loop_islands_add(r_island_store,
-                              num_lidx,
-                              loop_indices,
-                              num_pidx,
-                              poly_indices,
-                              num_einnercuts,
-                              edge_innercut_indices);
-  }
-
-  MEM_freeN(edge_poly_map);
-  MEM_freeN(edge_poly_mem);
-
-  if (luvs) {
-    MEM_freeN(edge_loop_map);
-    MEM_freeN(edge_loop_mem);
-  }
-
-  MEM_freeN(poly_indices);
-  MEM_freeN(loop_indices);
-  MEM_freeN(poly_groups);
-
-  if (edge_borders) {
-    MEM_freeN(edge_borders);
-  }
-
-  if (num_edge_borders) {
-    MEM_freeN(edge_border_count);
-    MEM_freeN(edge_innercut_indices);
-  }
-  return true;
-}
-
-bool BKE_mesh_calc_islands_loop_poly_edgeseam(MVert *verts,
-                                              const int totvert,
-                                              MEdge *edges,
-                                              const int totedge,
-                                              MPoly *polys,
-                                              const int totpoly,
-                                              MLoop *loops,
-                                              const int totloop,
-                                              MeshIslandStore *r_island_store)
-{
-  return mesh_calc_islands_loop_poly_uv(
-      verts, totvert, edges, totedge, polys, totpoly, loops, totloop, NULL, r_island_store);
-}
-
-bool BKE_mesh_calc_islands_loop_poly_uvmap(MVert *verts,
-                                           const int totvert,
-                                           MEdge *edges,
-                                           const int totedge,
-                                           MPoly *polys,
-                                           const int totpoly,
-                                           MLoop *loops,
-                                           const int totloop,
-                                           const MLoopUV *luvs,
-                                           MeshIslandStore *r_island_store)
-{
-  BLI_assert(luvs != NULL);
-  return mesh_calc_islands_loop_poly_uv(
-      verts, totvert, edges, totedge, polys, totpoly, loops, totloop, luvs, r_island_store);
-}
-
-/** \} */
diff --git a/source/blender/blenkernel/intern/mesh_mapping.cc b/source/blender/blenkernel/intern/mesh_mapping.cc
new file mode 100644
index 00000000000..db091361223
--- /dev/null
+++ b/source/blender/blenkernel/intern/mesh_mapping.cc
@@ -0,0 +1,1167 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/** \file
+ * \ingroup bke
+ *
+ * Functions for accessing mesh connectivity data.
+ * eg: polys connected to verts, UV's connected to verts.
+ */
+
+#include "MEM_guardedalloc.h"
+
+#include "DNA_meshdata_types.h"
+#include "DNA_vec_types.h"
+
+#include "BLI_array.hh"
+#include "BLI_bitmap.h"
+#include "BLI_buffer.h"
+#include "BLI_math.h"
+#include "BLI_utildefines.h"
+
+#include "BKE_customdata.h"
+#include "BKE_mesh_mapping.h"
+#include "BLI_memarena.h"
+
+#include "BLI_strict_flags.h"
+
+/* -------------------------------------------------------------------- */
+/** \name Mesh Connectivity Mapping
+ * \{ */
+
+/* ngon version wip, based on BM_uv_vert_map_create */
+UvVertMap *BKE_mesh_uv_vert_map_create(const MPoly *mpoly,
+                                       const bool *hide_poly,
+                                       const MLoop *mloop,
+                                       const MLoopUV *mloopuv,
+                                       uint totpoly,
+                                       uint totvert,
+                                       const float limit[2],
+                                       const bool selected,
+                                       const bool use_winding)
+{
+  UvVertMap *vmap;
+  UvMapVert *buf;
+  const MPoly *mp;
+  uint a;
+  int i, totuv, nverts;
+
+  bool *winding = NULL;
+  BLI_buffer_declare_static(vec2f, tf_uv_buf, BLI_BUFFER_NOP, 32);
+
+  totuv = 0;
+
+  /* generate UvMapVert array */
+  mp = mpoly;
+  for (a = 0; a < totpoly; a++, mp++) {
+    if (!selected || (!(hide_poly && hide_poly[a]) && (mp->flag & ME_FACE_SEL))) {
+      totuv += mp->totloop;
+    }
+  }
+
+  if (totuv == 0) {
+    return NULL;
+  }
+
+  vmap = (UvVertMap *)MEM_callocN(sizeof(*vmap), "UvVertMap");
+  buf = vmap->buf = (UvMapVert *)MEM_callocN(sizeof(*vmap->buf) * (size_t)totuv, "UvMapVert");
+  vmap->vert = (UvMapVert **)MEM_callocN(sizeof(*vmap->vert) * totvert, "UvMapVert*");
+  if (use_winding) {
+    winding = static_cast(MEM_callocN(sizeof(*winding) * totpoly, "winding"));
+  }
+
+  if (!vmap->vert || !vmap->buf) {
+    BKE_mesh_uv_vert_map_free(vmap);
+    return NULL;
+  }
+
+  mp = mpoly;
+  for (a = 0; a < totpoly; a++, mp++) {
+    if (!selected || (!(hide_poly && hide_poly[a]) && (mp->flag & ME_FACE_SEL))) {
+      float(*tf_uv)[2] = NULL;
+
+      if (use_winding) {
+        tf_uv = (float(*)[2])BLI_buffer_reinit_data(&tf_uv_buf, vec2f, (size_t)mp->totloop);
+      }
+
+      nverts = mp->totloop;
+
+      for (i = 0; i < nverts; i++) {
+        buf->loop_of_poly_index = (unsigned short)i;
+        buf->poly_index = a;
+        buf->separate = 0;
+        buf->next = vmap->vert[mloop[mp->loopstart + i].v];
+        vmap->vert[mloop[mp->loopstart + i].v] = buf;
+
+        if (use_winding) {
+          copy_v2_v2(tf_uv[i], mloopuv[mpoly[a].loopstart + i].uv);
+        }
+
+        buf++;
+      }
+
+      if (use_winding) {
+        winding[a] = cross_poly_v2(tf_uv, (uint)nverts) > 0;
+      }
+    }
+  }
+
+  /* sort individual uvs for each vert */
+  for (a = 0; a < totvert; a++) {
+    UvMapVert *newvlist = NULL, *vlist = vmap->vert[a];
+    UvMapVert *iterv, *v, *lastv, *next;
+    const float *uv, *uv2;
+    float uvdiff[2];
+
+    while (vlist) {
+      v = vlist;
+      vlist = vlist->next;
+      v->next = newvlist;
+      newvlist = v;
+
+      uv = mloopuv[mpoly[v->poly_index].loopstart + v->loop_of_poly_index].uv;
+      lastv = NULL;
+      iterv = vlist;
+
+      while (iterv) {
+        next = iterv->next;
+
+        uv2 = mloopuv[mpoly[iterv->poly_index].loopstart + iterv->loop_of_poly_index].uv;
+        sub_v2_v2v2(uvdiff, uv2, uv);
+
+        if (fabsf(uv[0] - uv2[0]) < limit[0] && fabsf(uv[1] - uv2[1]) < limit[1] &&
+            (!use_winding || winding[iterv->poly_index] == winding[v->poly_index])) {
+          if (lastv) {
+            lastv->next = next;
+          }
+          else {
+            vlist = next;
+          }
+          iterv->next = newvlist;
+          newvlist = iterv;
+        }
+        else {
+          lastv = iterv;
+        }
+
+        iterv = next;
+      }
+
+      newvlist->separate = 1;
+    }
+
+    vmap->vert[a] = newvlist;
+  }
+
+  if (use_winding) {
+    MEM_freeN(winding);
+  }
+
+  BLI_buffer_free(&tf_uv_buf);
+
+  return vmap;
+}
+
+UvMapVert *BKE_mesh_uv_vert_map_get_vert(UvVertMap *vmap, uint v)
+{
+  return vmap->vert[v];
+}
+
+void BKE_mesh_uv_vert_map_free(UvVertMap *vmap)
+{
+  if (vmap) {
+    if (vmap->vert) {
+      MEM_freeN(vmap->vert);
+    }
+    if (vmap->buf) {
+      MEM_freeN(vmap->buf);
+    }
+    MEM_freeN(vmap);
+  }
+}
+
+/**
+ * Generates a map where the key is the vertex and the value is a list
+ * of polys or loops that use that vertex as a corner. The lists are allocated
+ * from one memory pool.
+ *
+ * Wrapped by #BKE_mesh_vert_poly_map_create & BKE_mesh_vert_loop_map_create
+ */
+static void mesh_vert_poly_or_loop_map_create(MeshElemMap **r_map,
+                                              int **r_mem,
+                                              const MPoly *mpoly,
+                                              const MLoop *mloop,
+                                              int totvert,
+                                              int totpoly,
+                                              int totloop,
+                                              const bool do_loops)
+{
+  MeshElemMap *map = MEM_cnew_array((size_t)totvert, __func__);
+  int *indices, *index_iter;
+  int i, j;
+
+  indices = static_cast(MEM_mallocN(sizeof(int) * (size_t)totloop, __func__));
+  index_iter = indices;
+
+  /* Count number of polys for each vertex */
+  for (i = 0; i < totpoly; i++) {
+    const MPoly *p = &mpoly[i];
+
+    for (j = 0; j < p->totloop; j++) {
+      map[mloop[p->loopstart + j].v].count++;
+    }
+  }
+
+  /* Assign indices mem */
+  for (i = 0; i < totvert; i++) {
+    map[i].indices = index_iter;
+    index_iter += map[i].count;
+
+    /* Reset 'count' for use as index in last loop */
+    map[i].count = 0;
+  }
+
+  /* Find the users */
+  for (i = 0; i < totpoly; i++) {
+    const MPoly *p = &mpoly[i];
+
+    for (j = 0; j < p->totloop; j++) {
+      uint v = mloop[p->loopstart + j].v;
+
+      map[v].indices[map[v].count] = do_loops ? p->loopstart + j : i;
+      map[v].count++;
+    }
+  }
+
+  *r_map = map;
+  *r_mem = indices;
+}
+
+void BKE_mesh_vert_poly_map_create(MeshElemMap **r_map,
+                                   int **r_mem,
+                                   const MPoly *mpoly,
+                                   const MLoop *mloop,
+                                   int totvert,
+                                   int totpoly,
+                                   int totloop)
+{
+  mesh_vert_poly_or_loop_map_create(r_map, r_mem, mpoly, mloop, totvert, totpoly, totloop, false);
+}
+
+void BKE_mesh_vert_loop_map_create(MeshElemMap **r_map,
+                                   int **r_mem,
+                                   const MPoly *mpoly,
+                                   const MLoop *mloop,
+                                   int totvert,
+                                   int totpoly,
+                                   int totloop)
+{
+  mesh_vert_poly_or_loop_map_create(r_map, r_mem, mpoly, mloop, totvert, totpoly, totloop, true);
+}
+
+void BKE_mesh_vert_looptri_map_create(MeshElemMap **r_map,
+                                      int **r_mem,
+                                      const MVert *UNUSED(mvert),
+                                      const int totvert,
+                                      const MLoopTri *mlooptri,
+                                      const int totlooptri,
+                                      const MLoop *mloop,
+                                      const int UNUSED(totloop))
+{
+  MeshElemMap *map = MEM_cnew_array((size_t)totvert, __func__);
+  int *indices = static_cast(MEM_mallocN(sizeof(int) * (size_t)totlooptri * 3, __func__));
+  int *index_step;
+  const MLoopTri *mlt;
+  int i;
+
+  /* count face users */
+  for (i = 0, mlt = mlooptri; i < totlooptri; mlt++, i++) {
+    for (int j = 3; j--;) {
+      map[mloop[mlt->tri[j]].v].count++;
+    }
+  }
+
+  /* create offsets */
+  index_step = indices;
+  for (i = 0; i < totvert; i++) {
+    map[i].indices = index_step;
+    index_step += map[i].count;
+
+    /* re-count, using this as an index below */
+    map[i].count = 0;
+  }
+
+  /* assign looptri-edge users */
+  for (i = 0, mlt = mlooptri; i < totlooptri; mlt++, i++) {
+    for (int j = 3; j--;) {
+      MeshElemMap *map_ele = &map[mloop[mlt->tri[j]].v];
+      map_ele->indices[map_ele->count++] = i;
+    }
+  }
+
+  *r_map = map;
+  *r_mem = indices;
+}
+
+void BKE_mesh_vert_edge_map_create(
+    MeshElemMap **r_map, int **r_mem, const MEdge *medge, int totvert, int totedge)
+{
+  MeshElemMap *map = MEM_cnew_array((size_t)totvert, __func__);
+  int *indices = static_cast(MEM_mallocN(sizeof(int[2]) * (size_t)totedge, __func__));
+  int *i_pt = indices;
+
+  int i;
+
+  /* Count number of edges for each vertex */
+  for (i = 0; i < totedge; i++) {
+    map[medge[i].v1].count++;
+    map[medge[i].v2].count++;
+  }
+
+  /* Assign indices mem */
+  for (i = 0; i < totvert; i++) {
+    map[i].indices = i_pt;
+    i_pt += map[i].count;
+
+    /* Reset 'count' for use as index in last loop */
+    map[i].count = 0;
+  }
+
+  /* Find the users */
+  for (i = 0; i < totedge; i++) {
+    const uint v[2] = {medge[i].v1, medge[i].v2};
+
+    map[v[0]].indices[map[v[0]].count] = i;
+    map[v[1]].indices[map[v[1]].count] = i;
+
+    map[v[0]].count++;
+    map[v[1]].count++;
+  }
+
+  *r_map = map;
+  *r_mem = indices;
+}
+
+void BKE_mesh_vert_edge_vert_map_create(
+    MeshElemMap **r_map, int **r_mem, const MEdge *medge, int totvert, int totedge)
+{
+  MeshElemMap *map = MEM_cnew_array((size_t)totvert, __func__);
+  int *indices = static_cast(MEM_mallocN(sizeof(int[2]) * (size_t)totedge, __func__));
+  int *i_pt = indices;
+
+  int i;
+
+  /* Count number of edges for each vertex */
+  for (i = 0; i < totedge; i++) {
+    map[medge[i].v1].count++;
+    map[medge[i].v2].count++;
+  }
+
+  /* Assign indices mem */
+  for (i = 0; i < totvert; i++) {
+    map[i].indices = i_pt;
+    i_pt += map[i].count;
+
+    /* Reset 'count' for use as index in last loop */
+    map[i].count = 0;
+  }
+
+  /* Find the users */
+  for (i = 0; i < totedge; i++) {
+    const uint v[2] = {medge[i].v1, medge[i].v2};
+
+    map[v[0]].indices[map[v[0]].count] = (int)v[1];
+    map[v[1]].indices[map[v[1]].count] = (int)v[0];
+
+    map[v[0]].count++;
+    map[v[1]].count++;
+  }
+
+  *r_map = map;
+  *r_mem = indices;
+}
+
+void BKE_mesh_edge_loop_map_create(MeshElemMap **r_map,
+                                   int **r_mem,
+                                   const MEdge *UNUSED(medge),
+                                   const int totedge,
+                                   const MPoly *mpoly,
+                                   const int totpoly,
+                                   const MLoop *mloop,
+                                   const int totloop)
+{
+  MeshElemMap *map = MEM_cnew_array((size_t)totedge, __func__);
+  int *indices = static_cast(MEM_mallocN(sizeof(int) * (size_t)totloop * 2, __func__));
+  int *index_step;
+  const MPoly *mp;
+  int i;
+
+  /* count face users */
+  for (i = 0, mp = mpoly; i < totpoly; mp++, i++) {
+    const MLoop *ml;
+    int j = mp->totloop;
+    for (ml = &mloop[mp->loopstart]; j--; ml++) {
+      map[ml->e].count += 2;
+    }
+  }
+
+  /* create offsets */
+  index_step = indices;
+  for (i = 0; i < totedge; i++) {
+    map[i].indices = index_step;
+    index_step += map[i].count;
+
+    /* re-count, using this as an index below */
+    map[i].count = 0;
+  }
+
+  /* assign loop-edge users */
+  for (i = 0, mp = mpoly; i < totpoly; mp++, i++) {
+    const MLoop *ml;
+    MeshElemMap *map_ele;
+    const int max_loop = mp->loopstart + mp->totloop;
+    int j = mp->loopstart;
+    for (ml = &mloop[j]; j < max_loop; j++, ml++) {
+      map_ele = &map[ml->e];
+      map_ele->indices[map_ele->count++] = j;
+      map_ele->indices[map_ele->count++] = j + 1;
+    }
+    /* last edge/loop of poly, must point back to first loop! */
+    map_ele->indices[map_ele->count - 1] = mp->loopstart;
+  }
+
+  *r_map = map;
+  *r_mem = indices;
+}
+
+void BKE_mesh_edge_poly_map_create(MeshElemMap **r_map,
+                                   int **r_mem,
+                                   const MEdge *UNUSED(medge),
+                                   const int totedge,
+                                   const MPoly *mpoly,
+                                   const int totpoly,
+                                   const MLoop *mloop,
+                                   const int totloop)
+{
+  MeshElemMap *map = MEM_cnew_array((size_t)totedge, __func__);
+  int *indices = static_cast(MEM_mallocN(sizeof(int) * (size_t)totloop, __func__));
+  int *index_step;
+  const MPoly *mp;
+  int i;
+
+  /* count face users */
+  for (i = 0, mp = mpoly; i < totpoly; mp++, i++) {
+    const MLoop *ml;
+    int j = mp->totloop;
+    for (ml = &mloop[mp->loopstart]; j--; ml++) {
+      map[ml->e].count++;
+    }
+  }
+
+  /* create offsets */
+  index_step = indices;
+  for (i = 0; i < totedge; i++) {
+    map[i].indices = index_step;
+    index_step += map[i].count;
+
+    /* re-count, using this as an index below */
+    map[i].count = 0;
+  }
+
+  /* assign poly-edge users */
+  for (i = 0, mp = mpoly; i < totpoly; mp++, i++) {
+    const MLoop *ml;
+    int j = mp->totloop;
+    for (ml = &mloop[mp->loopstart]; j--; ml++) {
+      MeshElemMap *map_ele = &map[ml->e];
+      map_ele->indices[map_ele->count++] = i;
+    }
+  }
+
+  *r_map = map;
+  *r_mem = indices;
+}
+
+void BKE_mesh_origindex_map_create(MeshElemMap **r_map,
+                                   int **r_mem,
+                                   const int totsource,
+                                   const int *final_origindex,
+                                   const int totfinal)
+{
+  MeshElemMap *map = MEM_cnew_array((size_t)totsource, __func__);
+  int *indices = static_cast(MEM_mallocN(sizeof(int) * (size_t)totfinal, __func__));
+  int *index_step;
+  int i;
+
+  /* count face users */
+  for (i = 0; i < totfinal; i++) {
+    if (final_origindex[i] != ORIGINDEX_NONE) {
+      BLI_assert(final_origindex[i] < totsource);
+      map[final_origindex[i]].count++;
+    }
+  }
+
+  /* create offsets */
+  index_step = indices;
+  for (i = 0; i < totsource; i++) {
+    map[i].indices = index_step;
+    index_step += map[i].count;
+
+    /* re-count, using this as an index below */
+    map[i].count = 0;
+  }
+
+  /* assign poly-tessface users */
+  for (i = 0; i < totfinal; i++) {
+    if (final_origindex[i] != ORIGINDEX_NONE) {
+      MeshElemMap *map_ele = &map[final_origindex[i]];
+      map_ele->indices[map_ele->count++] = i;
+    }
+  }
+
+  *r_map = map;
+  *r_mem = indices;
+}
+
+void BKE_mesh_origindex_map_create_looptri(MeshElemMap **r_map,
+                                           int **r_mem,
+                                           const MPoly *mpoly,
+                                           const int mpoly_num,
+                                           const MLoopTri *looptri,
+                                           const int looptri_num)
+{
+  MeshElemMap *map = MEM_cnew_array((size_t)mpoly_num, __func__);
+  int *indices = static_cast(MEM_mallocN(sizeof(int) * (size_t)looptri_num, __func__));
+  int *index_step;
+  int i;
+
+  /* create offsets */
+  index_step = indices;
+  for (i = 0; i < mpoly_num; i++) {
+    map[i].indices = index_step;
+    index_step += ME_POLY_TRI_TOT(&mpoly[i]);
+  }
+
+  /* assign poly-tessface users */
+  for (i = 0; i < looptri_num; i++) {
+    MeshElemMap *map_ele = &map[looptri[i].poly];
+    map_ele->indices[map_ele->count++] = i;
+  }
+
+  *r_map = map;
+  *r_mem = indices;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Mesh loops/poly islands.
+ * Used currently for UVs and 'smooth groups'.
+ * \{ */
+
+/**
+ * Callback deciding whether the given poly/loop/edge define an island boundary or not.
+ */
+using MeshRemap_CheckIslandBoundary = bool (*)(const MPoly *mpoly,
+                                               const MLoop *mloop,
+                                               const MEdge *medge,
+                                               const int edge_user_count,
+                                               const MPoly *mpoly_array,
+                                               const MeshElemMap *edge_poly_map,
+                                               void *user_data);
+
+static void poly_edge_loop_islands_calc(const MEdge *medge,
+                                        const int totedge,
+                                        const MPoly *mpoly,
+                                        const int totpoly,
+                                        const MLoop *mloop,
+                                        const int totloop,
+                                        MeshElemMap *edge_poly_map,
+                                        const bool use_bitflags,
+                                        MeshRemap_CheckIslandBoundary edge_boundary_check,
+                                        void *edge_boundary_check_data,
+                                        int **r_poly_groups,
+                                        int *r_totgroup,
+                                        BLI_bitmap **r_edge_borders,
+                                        int *r_totedgeborder)
+{
+  int *poly_groups;
+  int *poly_stack;
+
+  BLI_bitmap *edge_borders = NULL;
+  int num_edgeborders = 0;
+
+  int poly_prev = 0;
+  const int temp_poly_group_id = 3; /* Placeholder value. */
+
+  /* Group we could not find any available bit, will be reset to 0 at end. */
+  const int poly_group_id_overflowed = 5;
+
+  int tot_group = 0;
+  bool group_id_overflow = false;
+
+  /* map vars */
+  int *edge_poly_mem = NULL;
+
+  if (totpoly == 0) {
+    *r_totgroup = 0;
+    *r_poly_groups = NULL;
+    if (r_edge_borders) {
+      *r_edge_borders = NULL;
+      *r_totedgeborder = 0;
+    }
+    return;
+  }
+
+  if (r_edge_borders) {
+    edge_borders = BLI_BITMAP_NEW(totedge, __func__);
+    *r_totedgeborder = 0;
+  }
+
+  if (!edge_poly_map) {
+    BKE_mesh_edge_poly_map_create(
+        &edge_poly_map, &edge_poly_mem, medge, totedge, mpoly, totpoly, mloop, totloop);
+  }
+
+  poly_groups = static_cast(MEM_callocN(sizeof(int) * (size_t)totpoly, __func__));
+  poly_stack = static_cast(MEM_mallocN(sizeof(int) * (size_t)totpoly, __func__));
+
+  while (true) {
+    int poly;
+    int bit_poly_group_mask = 0;
+    int poly_group_id;
+    int ps_curr_idx = 0, ps_end_idx = 0; /* stack indices */
+
+    for (poly = poly_prev; poly < totpoly; poly++) {
+      if (poly_groups[poly] == 0) {
+        break;
+      }
+    }
+
+    if (poly == totpoly) {
+      /* all done */
+      break;
+    }
+
+    poly_group_id = use_bitflags ? temp_poly_group_id : ++tot_group;
+
+    /* start searching from here next time */
+    poly_prev = poly + 1;
+
+    poly_groups[poly] = poly_group_id;
+    poly_stack[ps_end_idx++] = poly;
+
+    while (ps_curr_idx != ps_end_idx) {
+      const MPoly *mp;
+      const MLoop *ml;
+      int j;
+
+      poly = poly_stack[ps_curr_idx++];
+      BLI_assert(poly_groups[poly] == poly_group_id);
+
+      mp = &mpoly[poly];
+      for (ml = &mloop[mp->loopstart], j = mp->totloop; j--; ml++) {
+        /* loop over poly users */
+        const int me_idx = (int)ml->e;
+        const MEdge *me = &medge[me_idx];
+        const MeshElemMap *map_ele = &edge_poly_map[me_idx];
+        const int *p = map_ele->indices;
+        int i = map_ele->count;
+        if (!edge_boundary_check(mp, ml, me, i, mpoly, map_ele, edge_boundary_check_data)) {
+          for (; i--; p++) {
+            /* if we meet other non initialized its a bug */
+            BLI_assert(ELEM(poly_groups[*p], 0, poly_group_id));
+
+            if (poly_groups[*p] == 0) {
+              poly_groups[*p] = poly_group_id;
+              poly_stack[ps_end_idx++] = *p;
+            }
+          }
+        }
+        else {
+          if (edge_borders && !BLI_BITMAP_TEST(edge_borders, me_idx)) {
+            BLI_BITMAP_ENABLE(edge_borders, me_idx);
+            num_edgeborders++;
+          }
+          if (use_bitflags) {
+            /* Find contiguous smooth groups already assigned,
+             * these are the values we can't reuse! */
+            for (; i--; p++) {
+              int bit = poly_groups[*p];
+              if (!ELEM(bit, 0, poly_group_id, poly_group_id_overflowed) &&
+                  !(bit_poly_group_mask & bit)) {
+                bit_poly_group_mask |= bit;
+              }
+            }
+          }
+        }
+      }
+    }
+    /* And now, we have all our poly from current group in poly_stack
+     * (from 0 to (ps_end_idx - 1)),
+     * as well as all smoothgroups bits we can't use in bit_poly_group_mask.
+     */
+    if (use_bitflags) {
+      int i, *p, gid_bit = 0;
+      poly_group_id = 1;
+
+      /* Find first bit available! */
+      for (; (poly_group_id & bit_poly_group_mask) && (gid_bit < 32); gid_bit++) {
+        poly_group_id <<= 1; /* will 'overflow' on last possible iteration. */
+      }
+      if (UNLIKELY(gid_bit > 31)) {
+        /* All bits used in contiguous smooth groups, we can't do much!
+         * NOTE: this is *very* unlikely - theoretically, four groups are enough,
+         *       I don't think we can reach this goal with such a simple algorithm,
+         *       but I don't think either we'll never need all 32 groups!
+         */
+        printf(
+            "Warning, could not find an available id for current smooth group, faces will me "
+            "marked "
+            "as out of any smooth group...\n");
+
+        /* Can't use 0, will have to set them to this value later. */
+        poly_group_id = poly_group_id_overflowed;
+
+        group_id_overflow = true;
+      }
+      if (gid_bit > tot_group) {
+        tot_group = gid_bit;
+      }
+      /* And assign the final smooth group id to that poly group! */
+      for (i = ps_end_idx, p = poly_stack; i--; p++) {
+        poly_groups[*p] = poly_group_id;
+      }
+    }
+  }
+
+  if (use_bitflags) {
+    /* used bits are zero-based. */
+    tot_group++;
+  }
+
+  if (UNLIKELY(group_id_overflow)) {
+    int i = totpoly, *gid = poly_groups;
+    for (; i--; gid++) {
+      if (*gid == poly_group_id_overflowed) {
+        *gid = 0;
+      }
+    }
+    /* Using 0 as group id adds one more group! */
+    tot_group++;
+  }
+
+  if (edge_poly_mem) {
+    MEM_freeN(edge_poly_map);
+    MEM_freeN(edge_poly_mem);
+  }
+  MEM_freeN(poly_stack);
+
+  *r_totgroup = tot_group;
+  *r_poly_groups = poly_groups;
+  if (r_edge_borders) {
+    *r_edge_borders = edge_borders;
+    *r_totedgeborder = num_edgeborders;
+  }
+}
+
+static bool poly_is_island_boundary_smooth_cb(const MPoly *mp,
+                                              const MLoop *UNUSED(ml),
+                                              const MEdge *me,
+                                              const int edge_user_count,
+                                              const MPoly *mpoly_array,
+                                              const MeshElemMap *edge_poly_map,
+                                              void *UNUSED(user_data))
+{
+  /* Edge is sharp if one of its polys is flat, or edge itself is sharp,
+   * or edge is not used by exactly two polygons. */
+  if ((mp->flag & ME_SMOOTH) && !(me->flag & ME_SHARP) && (edge_user_count == 2)) {
+    /* In that case, edge appears to be smooth, but we need to check its other poly too. */
+    const MPoly *mp_other = (mp == &mpoly_array[edge_poly_map->indices[0]]) ?
+                                &mpoly_array[edge_poly_map->indices[1]] :
+                                &mpoly_array[edge_poly_map->indices[0]];
+    return (mp_other->flag & ME_SMOOTH) == 0;
+  }
+  return true;
+}
+
+int *BKE_mesh_calc_smoothgroups(const MEdge *medge,
+                                const int totedge,
+                                const MPoly *mpoly,
+                                const int totpoly,
+                                const MLoop *mloop,
+                                const int totloop,
+                                int *r_totgroup,
+                                const bool use_bitflags)
+{
+  int *poly_groups = NULL;
+
+  poly_edge_loop_islands_calc(medge,
+                              totedge,
+                              mpoly,
+                              totpoly,
+                              mloop,
+                              totloop,
+                              NULL,
+                              use_bitflags,
+                              poly_is_island_boundary_smooth_cb,
+                              NULL,
+                              &poly_groups,
+                              r_totgroup,
+                              NULL,
+                              NULL);
+
+  return poly_groups;
+}
+
+#define MISLAND_DEFAULT_BUFSIZE 64
+
+void BKE_mesh_loop_islands_init(MeshIslandStore *island_store,
+                                const short item_type,
+                                const int items_num,
+                                const short island_type,
+                                const short innercut_type)
+{
+  MemArena *mem = island_store->mem;
+
+  if (mem == NULL) {
+    mem = BLI_memarena_new(BLI_MEMARENA_STD_BUFSIZE, __func__);
+    island_store->mem = mem;
+  }
+  /* else memarena should be cleared */
+
+  BLI_assert(
+      ELEM(item_type, MISLAND_TYPE_VERT, MISLAND_TYPE_EDGE, MISLAND_TYPE_POLY, MISLAND_TYPE_LOOP));
+  BLI_assert(ELEM(
+      island_type, MISLAND_TYPE_VERT, MISLAND_TYPE_EDGE, MISLAND_TYPE_POLY, MISLAND_TYPE_LOOP));
+
+  island_store->item_type = item_type;
+  island_store->items_to_islands_num = items_num;
+  island_store->items_to_islands = static_cast(
+      BLI_memarena_alloc(mem, sizeof(*island_store->items_to_islands) * (size_t)items_num));
+
+  island_store->island_type = island_type;
+  island_store->islands_num_alloc = MISLAND_DEFAULT_BUFSIZE;
+  island_store->islands = static_cast(
+      BLI_memarena_alloc(mem, sizeof(*island_store->islands) * island_store->islands_num_alloc));
+
+  island_store->innercut_type = innercut_type;
+  island_store->innercuts = static_cast(
+      BLI_memarena_alloc(mem, sizeof(*island_store->innercuts) * island_store->islands_num_alloc));
+}
+
+void BKE_mesh_loop_islands_clear(MeshIslandStore *island_store)
+{
+  island_store->item_type = MISLAND_TYPE_NONE;
+  island_store->items_to_islands_num = 0;
+  island_store->items_to_islands = NULL;
+
+  island_store->island_type = MISLAND_TYPE_NONE;
+  island_store->islands_num = 0;
+  island_store->islands = NULL;
+
+  island_store->innercut_type = MISLAND_TYPE_NONE;
+  island_store->innercuts = NULL;
+
+  if (island_store->mem) {
+    BLI_memarena_clear(island_store->mem);
+  }
+
+  island_store->islands_num_alloc = 0;
+}
+
+void BKE_mesh_loop_islands_free(MeshIslandStore *island_store)
+{
+  if (island_store->mem) {
+    BLI_memarena_free(island_store->mem);
+    island_store->mem = NULL;
+  }
+}
+
+void BKE_mesh_loop_islands_add(MeshIslandStore *island_store,
+                               const int item_num,
+                               const int *items_indices,
+                               const int num_island_items,
+                               int *island_item_indices,
+                               const int num_innercut_items,
+                               int *innercut_item_indices)
+{
+  MemArena *mem = island_store->mem;
+
+  MeshElemMap *isld, *innrcut;
+  const int curr_island_idx = island_store->islands_num++;
+  const size_t curr_num_islands = (size_t)island_store->islands_num;
+  int i = item_num;
+
+  while (i--) {
+    island_store->items_to_islands[items_indices[i]] = curr_island_idx;
+  }
+
+  if (UNLIKELY(curr_num_islands > island_store->islands_num_alloc)) {
+    MeshElemMap **islds, **innrcuts;
+
+    island_store->islands_num_alloc *= 2;
+    islds = static_cast(
+        BLI_memarena_alloc(mem, sizeof(*islds) * island_store->islands_num_alloc));
+    memcpy(islds, island_store->islands, sizeof(*islds) * (curr_num_islands - 1));
+    island_store->islands = islds;
+
+    innrcuts = static_cast(
+        BLI_memarena_alloc(mem, sizeof(*innrcuts) * island_store->islands_num_alloc));
+    memcpy(innrcuts, island_store->innercuts, sizeof(*innrcuts) * (curr_num_islands - 1));
+    island_store->innercuts = innrcuts;
+  }
+
+  island_store->islands[curr_island_idx] = isld = static_cast(
+      BLI_memarena_alloc(mem, sizeof(*isld)));
+  isld->count = num_island_items;
+  isld->indices = static_cast(
+      BLI_memarena_alloc(mem, sizeof(*isld->indices) * (size_t)num_island_items));
+  memcpy(isld->indices, island_item_indices, sizeof(*isld->indices) * (size_t)num_island_items);
+
+  island_store->innercuts[curr_island_idx] = innrcut = static_cast(
+      BLI_memarena_alloc(mem, sizeof(*innrcut)));
+  innrcut->count = num_innercut_items;
+  innrcut->indices = static_cast(
+      BLI_memarena_alloc(mem, sizeof(*innrcut->indices) * (size_t)num_innercut_items));
+  memcpy(innrcut->indices,
+         innercut_item_indices,
+         sizeof(*innrcut->indices) * (size_t)num_innercut_items);
+}
+
+/* TODO: I'm not sure edge seam flag is enough to define UV islands?
+ *       Maybe we should also consider UV-maps values
+ *       themselves (i.e. different UV-edges for a same mesh-edge => boundary edge too?).
+ *       Would make things much more complex though,
+ *       and each UVMap would then need its own mesh mapping, not sure we want that at all!
+ */
+struct MeshCheckIslandBoundaryUv {
+  const MLoop *loops;
+  const MLoopUV *luvs;
+  const MeshElemMap *edge_loop_map;
+};
+
+static bool mesh_check_island_boundary_uv(const MPoly *UNUSED(mp),
+                                          const MLoop *ml,
+                                          const MEdge *me,
+                                          const int UNUSED(edge_user_count),
+                                          const MPoly *UNUSED(mpoly_array),
+                                          const MeshElemMap *UNUSED(edge_poly_map),
+                                          void *user_data)
+{
+  if (user_data) {
+    const MeshCheckIslandBoundaryUv *data = static_cast(
+        user_data);
+    const MLoop *loops = data->loops;
+    const MLoopUV *luvs = data->luvs;
+    const MeshElemMap *edge_to_loops = &data->edge_loop_map[ml->e];
+
+    BLI_assert(edge_to_loops->count >= 2 && (edge_to_loops->count % 2) == 0);
+
+    const uint v1 = loops[edge_to_loops->indices[0]].v;
+    const uint v2 = loops[edge_to_loops->indices[1]].v;
+    const float *uvco_v1 = luvs[edge_to_loops->indices[0]].uv;
+    const float *uvco_v2 = luvs[edge_to_loops->indices[1]].uv;
+    for (int i = 2; i < edge_to_loops->count; i += 2) {
+      if (loops[edge_to_loops->indices[i]].v == v1) {
+        if (!equals_v2v2(uvco_v1, luvs[edge_to_loops->indices[i]].uv) ||
+            !equals_v2v2(uvco_v2, luvs[edge_to_loops->indices[i + 1]].uv)) {
+          return true;
+        }
+      }
+      else {
+        BLI_assert(loops[edge_to_loops->indices[i]].v == v2);
+        UNUSED_VARS_NDEBUG(v2);
+        if (!equals_v2v2(uvco_v2, luvs[edge_to_loops->indices[i]].uv) ||
+            !equals_v2v2(uvco_v1, luvs[edge_to_loops->indices[i + 1]].uv)) {
+          return true;
+        }
+      }
+    }
+    return false;
+  }
+
+  /* Edge is UV boundary if tagged as seam. */
+  return (me->flag & ME_SEAM) != 0;
+}
+
+static bool mesh_calc_islands_loop_poly_uv(const MVert *UNUSED(verts),
+                                           const int UNUSED(totvert),
+                                           const MEdge *edges,
+                                           const int totedge,
+                                           const MPoly *polys,
+                                           const int totpoly,
+                                           const MLoop *loops,
+                                           const int totloop,
+                                           const MLoopUV *luvs,
+                                           MeshIslandStore *r_island_store)
+{
+  int *poly_groups = NULL;
+  int num_poly_groups;
+
+  /* map vars */
+  MeshElemMap *edge_poly_map;
+  int *edge_poly_mem;
+
+  MeshElemMap *edge_loop_map;
+  int *edge_loop_mem;
+
+  MeshCheckIslandBoundaryUv edge_boundary_check_data;
+
+  int *poly_indices;
+  int *loop_indices;
+  int num_pidx, num_lidx;
+
+  /* Those are used to detect 'inner cuts', i.e. edges that are borders,
+   * and yet have two or more polys of a same group using them
+   * (typical case: seam used to unwrap properly a cylinder). */
+  BLI_bitmap *edge_borders = NULL;
+  int num_edge_borders = 0;
+  char *edge_border_count = NULL;
+  int *edge_innercut_indices = NULL;
+  int num_einnercuts = 0;
+
+  int grp_idx, p_idx, pl_idx, l_idx;
+
+  BKE_mesh_loop_islands_clear(r_island_store);
+  BKE_mesh_loop_islands_init(
+      r_island_store, MISLAND_TYPE_LOOP, totloop, MISLAND_TYPE_POLY, MISLAND_TYPE_EDGE);
+
+  BKE_mesh_edge_poly_map_create(
+      &edge_poly_map, &edge_poly_mem, edges, totedge, polys, totpoly, loops, totloop);
+
+  if (luvs) {
+    BKE_mesh_edge_loop_map_create(
+        &edge_loop_map, &edge_loop_mem, edges, totedge, polys, totpoly, loops, totloop);
+    edge_boundary_check_data.loops = loops;
+    edge_boundary_check_data.luvs = luvs;
+    edge_boundary_check_data.edge_loop_map = edge_loop_map;
+  }
+
+  poly_edge_loop_islands_calc(edges,
+                              totedge,
+                              polys,
+                              totpoly,
+                              loops,
+                              totloop,
+                              edge_poly_map,
+                              false,
+                              mesh_check_island_boundary_uv,
+                              luvs ? &edge_boundary_check_data : NULL,
+                              &poly_groups,
+                              &num_poly_groups,
+                              &edge_borders,
+                              &num_edge_borders);
+
+  if (!num_poly_groups) {
+    /* Should never happen... */
+    MEM_freeN(edge_poly_map);
+    MEM_freeN(edge_poly_mem);
+
+    if (edge_borders) {
+      MEM_freeN(edge_borders);
+    }
+    return false;
+  }
+
+  if (num_edge_borders) {
+    edge_border_count = static_cast(
+        MEM_mallocN(sizeof(*edge_border_count) * (size_t)totedge, __func__));
+    edge_innercut_indices = static_cast(
+        MEM_mallocN(sizeof(*edge_innercut_indices) * (size_t)num_edge_borders, __func__));
+  }
+
+  poly_indices = static_cast(
+      MEM_mallocN(sizeof(*poly_indices) * (size_t)totpoly, __func__));
+  loop_indices = static_cast(
+      MEM_mallocN(sizeof(*loop_indices) * (size_t)totloop, __func__));
+
+  /* NOTE: here we ignore '0' invalid group - this should *never* happen in this case anyway? */
+  for (grp_idx = 1; grp_idx <= num_poly_groups; grp_idx++) {
+    num_pidx = num_lidx = 0;
+    if (num_edge_borders) {
+      num_einnercuts = 0;
+      memset(edge_border_count, 0, sizeof(*edge_border_count) * (size_t)totedge);
+    }
+
+    for (p_idx = 0; p_idx < totpoly; p_idx++) {
+      if (poly_groups[p_idx] != grp_idx) {
+        continue;
+      }
+      const MPoly *mp = &polys[p_idx];
+      poly_indices[num_pidx++] = p_idx;
+      for (l_idx = mp->loopstart, pl_idx = 0; pl_idx < mp->totloop; l_idx++, pl_idx++) {
+        const MLoop *ml = &loops[l_idx];
+        loop_indices[num_lidx++] = l_idx;
+        if (num_edge_borders && BLI_BITMAP_TEST(edge_borders, ml->e) &&
+            (edge_border_count[ml->e] < 2)) {
+          edge_border_count[ml->e]++;
+          if (edge_border_count[ml->e] == 2) {
+            edge_innercut_indices[num_einnercuts++] = (int)ml->e;
+          }
+        }
+      }
+    }
+
+    BKE_mesh_loop_islands_add(r_island_store,
+                              num_lidx,
+                              loop_indices,
+                              num_pidx,
+                              poly_indices,
+                              num_einnercuts,
+                              edge_innercut_indices);
+  }
+
+  MEM_freeN(edge_poly_map);
+  MEM_freeN(edge_poly_mem);
+
+  if (luvs) {
+    MEM_freeN(edge_loop_map);
+    MEM_freeN(edge_loop_mem);
+  }
+
+  MEM_freeN(poly_indices);
+  MEM_freeN(loop_indices);
+  MEM_freeN(poly_groups);
+
+  if (edge_borders) {
+    MEM_freeN(edge_borders);
+  }
+
+  if (num_edge_borders) {
+    MEM_freeN(edge_border_count);
+    MEM_freeN(edge_innercut_indices);
+  }
+  return true;
+}
+
+bool BKE_mesh_calc_islands_loop_poly_edgeseam(const MVert *verts,
+                                              const int totvert,
+                                              const MEdge *edges,
+                                              const int totedge,
+                                              const MPoly *polys,
+                                              const int totpoly,
+                                              const MLoop *loops,
+                                              const int totloop,
+                                              MeshIslandStore *r_island_store)
+{
+  return mesh_calc_islands_loop_poly_uv(
+      verts, totvert, edges, totedge, polys, totpoly, loops, totloop, NULL, r_island_store);
+}
+
+bool BKE_mesh_calc_islands_loop_poly_uvmap(MVert *verts,
+                                           const int totvert,
+                                           MEdge *edges,
+                                           const int totedge,
+                                           MPoly *polys,
+                                           const int totpoly,
+                                           MLoop *loops,
+                                           const int totloop,
+                                           const MLoopUV *luvs,
+                                           MeshIslandStore *r_island_store)
+{
+  BLI_assert(luvs != NULL);
+  return mesh_calc_islands_loop_poly_uv(
+      verts, totvert, edges, totedge, polys, totpoly, loops, totloop, luvs, r_island_store);
+}
+
+/** \} */
diff --git a/source/blender/blenkernel/intern/mesh_merge.c b/source/blender/blenkernel/intern/mesh_merge.c
index 4459e2514bc..9c0e3c1bf59 100644
--- a/source/blender/blenkernel/intern/mesh_merge.c
+++ b/source/blender/blenkernel/intern/mesh_merge.c
@@ -32,9 +32,9 @@
  * and may be called again with direct_reverse=-1 for reverse order.
  * \return 1 if polys are identical,  0 if polys are different.
  */
-static int cddm_poly_compare(MLoop *mloop_array,
-                             MPoly *mpoly_source,
-                             MPoly *mpoly_target,
+static int cddm_poly_compare(const MLoop *mloop_array,
+                             const MPoly *mpoly_source,
+                             const MPoly *mpoly_target,
                              const int *vtargetmap,
                              const int direct_reverse)
 {
@@ -44,7 +44,7 @@ static int cddm_poly_compare(MLoop *mloop_array,
   bool compare_completed = false;
   bool same_loops = false;
 
-  MLoop *mloop_source, *mloop_target;
+  const MLoop *mloop_source, *mloop_target;
 
   BLI_assert(ELEM(direct_reverse, 1, -1));
 
@@ -203,10 +203,15 @@ Mesh *BKE_mesh_merge_verts(Mesh *mesh,
   const int totedge = mesh->totedge;
   const int totloop = mesh->totloop;
   const int totpoly = mesh->totpoly;
+  const MVert *src_verts = BKE_mesh_verts(mesh);
+  const MEdge *src_edges = BKE_mesh_edges(mesh);
+  const MPoly *src_polys = BKE_mesh_polys(mesh);
+  const MLoop *src_loops = BKE_mesh_loops(mesh);
 
   const int totvert_final = totvert - tot_vtargetmap;
 
-  MVert *mv, *mvert = MEM_malloc_arrayN(totvert_final, sizeof(*mvert), __func__);
+  const MVert *mv;
+  MVert *mvert = MEM_malloc_arrayN(totvert_final, sizeof(*mvert), __func__);
   int *oldv = MEM_malloc_arrayN(totvert_final, sizeof(*oldv), __func__);
   int *newv = MEM_malloc_arrayN(totvert, sizeof(*newv), __func__);
   STACK_DECLARE(mvert);
@@ -215,13 +220,15 @@ Mesh *BKE_mesh_merge_verts(Mesh *mesh,
   /* NOTE: create (totedge + totloop) elements because partially invalid polys due to merge may
    * require generating new edges, and while in 99% cases we'll still end with less final edges
    * than totedge, cases can be forged that would end requiring more. */
-  MEdge *med, *medge = MEM_malloc_arrayN((totedge + totloop), sizeof(*medge), __func__);
+  const MEdge *med;
+  MEdge *medge = MEM_malloc_arrayN((totedge + totloop), sizeof(*medge), __func__);
   int *olde = MEM_malloc_arrayN((totedge + totloop), sizeof(*olde), __func__);
   int *newe = MEM_malloc_arrayN((totedge + totloop), sizeof(*newe), __func__);
   STACK_DECLARE(medge);
   STACK_DECLARE(olde);
 
-  MLoop *ml, *mloop = MEM_malloc_arrayN(totloop, sizeof(*mloop), __func__);
+  const MLoop *ml;
+  MLoop *mloop = MEM_malloc_arrayN(totloop, sizeof(*mloop), __func__);
   int *oldl = MEM_malloc_arrayN(totloop, sizeof(*oldl), __func__);
 #ifdef USE_LOOPS
   int *newl = MEM_malloc_arrayN(totloop, sizeof(*newl), __func__);
@@ -229,7 +236,8 @@ Mesh *BKE_mesh_merge_verts(Mesh *mesh,
   STACK_DECLARE(mloop);
   STACK_DECLARE(oldl);
 
-  MPoly *mp, *mpoly = MEM_malloc_arrayN(totpoly, sizeof(*medge), __func__);
+  const MPoly *mp;
+  MPoly *mpoly = MEM_malloc_arrayN(totpoly, sizeof(*medge), __func__);
   int *oldp = MEM_malloc_arrayN(totpoly, sizeof(*oldp), __func__);
   STACK_DECLARE(mpoly);
   STACK_DECLARE(oldp);
@@ -254,7 +262,7 @@ Mesh *BKE_mesh_merge_verts(Mesh *mesh,
   STACK_INIT(mpoly, totpoly);
 
   /* fill newv with destination vertex indices */
-  mv = mesh->mvert;
+  mv = src_verts;
   c = 0;
   for (i = 0; i < totvert; i++, mv++) {
     if (vtargetmap[i] == -1) {
@@ -281,7 +289,7 @@ Mesh *BKE_mesh_merge_verts(Mesh *mesh,
    */
 
   /* now go through and fix edges and faces */
-  med = mesh->medge;
+  med = src_edges;
   c = 0;
   for (i = 0; i < totedge; i++, med++) {
     const uint v1 = (vtargetmap[med->v1] != -1) ? vtargetmap[med->v1] : med->v1;
@@ -316,12 +324,12 @@ Mesh *BKE_mesh_merge_verts(Mesh *mesh,
     /* Duplicates allowed because our compare function is not pure equality */
     BLI_gset_flag_set(poly_gset, GHASH_FLAG_ALLOW_DUPES);
 
-    mp = mesh->mpoly;
+    mp = src_polys;
     mpgh = poly_keys;
     for (i = 0; i < totpoly; i++, mp++, mpgh++) {
       mpgh->poly_index = i;
       mpgh->totloops = mp->totloop;
-      ml = mesh->mloop + mp->loopstart;
+      ml = src_loops + mp->loopstart;
       mpgh->hash_sum = mpgh->hash_xor = 0;
       for (j = 0; j < mp->totloop; j++, ml++) {
         mpgh->hash_sum += ml->v;
@@ -333,24 +341,24 @@ Mesh *BKE_mesh_merge_verts(Mesh *mesh,
     /* Can we optimize by reusing an old `pmap`? How do we know an old `pmap` is stale? */
     /* When called by `MOD_array.c` the `cddm` has just been created, so it has no valid `pmap`. */
     BKE_mesh_vert_poly_map_create(
-        &poly_map, &poly_map_mem, mesh->mpoly, mesh->mloop, totvert, totpoly, totloop);
+        &poly_map, &poly_map_mem, src_polys, src_loops, totvert, totpoly, totloop);
   } /* done preparing for fast poly compare */
 
   BLI_bitmap *vert_tag = BLI_BITMAP_NEW(mesh->totvert, __func__);
 
-  mp = mesh->mpoly;
-  mv = mesh->mvert;
+  mp = src_polys;
+  mv = src_verts;
   for (i = 0; i < totpoly; i++, mp++) {
     MPoly *mp_new;
 
-    ml = mesh->mloop + mp->loopstart;
+    ml = src_loops + mp->loopstart;
 
     /* check faces with all vertices merged */
-    bool all_vertices_merged = true;
+    bool all_verts_merged = true;
 
     for (j = 0; j < mp->totloop; j++, ml++) {
       if (vtargetmap[ml->v] == -1) {
-        all_vertices_merged = false;
+        all_verts_merged = false;
         /* This will be used to check for poly using several time the same vert. */
         BLI_BITMAP_DISABLE(vert_tag, ml->v);
       }
@@ -360,7 +368,7 @@ Mesh *BKE_mesh_merge_verts(Mesh *mesh,
       }
     }
 
-    if (UNLIKELY(all_vertices_merged)) {
+    if (UNLIKELY(all_verts_merged)) {
       if (merge_mode == MESH_MERGE_VERTS_DUMP_IF_MAPPED) {
         /* In this mode, all vertices merged is enough to dump face */
         continue;
@@ -376,7 +384,7 @@ Mesh *BKE_mesh_merge_verts(Mesh *mesh,
 
         /* Use poly_gset for fast (although not 100% certain) identification of same poly */
         /* First, make up a poly_summary structure */
-        ml = mesh->mloop + mp->loopstart;
+        ml = src_loops + mp->loopstart;
         pkey.hash_sum = pkey.hash_xor = 0;
         pkey.totloops = 0;
         for (j = 0; j < mp->totloop; j++, ml++) {
@@ -394,17 +402,17 @@ Mesh *BKE_mesh_merge_verts(Mesh *mesh,
            */
 
           /* Consider current loop again */
-          ml = mesh->mloop + mp->loopstart;
+          ml = src_loops + mp->loopstart;
           /* Consider the target of the loop's first vert */
           v_target = vtargetmap[ml->v];
           /* Now see if v_target belongs to a poly that shares all vertices with source poly,
            * in same order, or reverse order */
 
           for (i_poly = 0; i_poly < poly_map[v_target].count; i_poly++) {
-            MPoly *target_poly = mesh->mpoly + *(poly_map[v_target].indices + i_poly);
+            const MPoly *target_poly = src_polys + *(poly_map[v_target].indices + i_poly);
 
-            if (cddm_poly_compare(mesh->mloop, mp, target_poly, vtargetmap, +1) ||
-                cddm_poly_compare(mesh->mloop, mp, target_poly, vtargetmap, -1)) {
+            if (cddm_poly_compare(src_loops, mp, target_poly, vtargetmap, +1) ||
+                cddm_poly_compare(src_loops, mp, target_poly, vtargetmap, -1)) {
               found = true;
               break;
             }
@@ -422,7 +430,7 @@ Mesh *BKE_mesh_merge_verts(Mesh *mesh,
      * or they were all merged, but targets do not make up an identical poly,
      * the poly is retained.
      */
-    ml = mesh->mloop + mp->loopstart;
+    ml = src_loops + mp->loopstart;
 
     c = 0;
     MLoop *last_valid_ml = NULL;
@@ -434,9 +442,9 @@ Mesh *BKE_mesh_merge_verts(Mesh *mesh,
       const uint mlv = (vtargetmap[ml->v] != -1) ? vtargetmap[ml->v] : ml->v;
 #ifndef NDEBUG
       {
-        MLoop *next_ml = mesh->mloop + mp->loopstart + ((j + 1) % mp->totloop);
+        const MLoop *next_ml = src_loops + mp->loopstart + ((j + 1) % mp->totloop);
         uint next_mlv = (vtargetmap[next_ml->v] != -1) ? vtargetmap[next_ml->v] : next_ml->v;
-        med = mesh->medge + ml->e;
+        med = src_edges + ml->e;
         uint v1 = (vtargetmap[med->v1] != -1) ? vtargetmap[med->v1] : med->v1;
         uint v2 = (vtargetmap[med->v2] != -1) ? vtargetmap[med->v2] : med->v2;
         BLI_assert((mlv == v1 && next_mlv == v2) || (mlv == v2 && next_mlv == v1));
@@ -461,7 +469,7 @@ Mesh *BKE_mesh_merge_verts(Mesh *mesh,
           else {
             const int new_eidx = STACK_SIZE(medge);
             STACK_PUSH(olde, olde[last_valid_ml->e]);
-            STACK_PUSH(medge, mesh->medge[last_valid_ml->e]);
+            STACK_PUSH(medge, src_edges[last_valid_ml->e]);
             medge[new_eidx].v1 = last_valid_ml->v;
             medge[new_eidx].v2 = ml->v;
             /* DO NOT change newe mapping,
@@ -515,7 +523,7 @@ Mesh *BKE_mesh_merge_verts(Mesh *mesh,
       else {
         const int new_eidx = STACK_SIZE(medge);
         STACK_PUSH(olde, olde[last_valid_ml->e]);
-        STACK_PUSH(medge, mesh->medge[last_valid_ml->e]);
+        STACK_PUSH(medge, src_edges[last_valid_ml->e]);
         medge[new_eidx].v1 = last_valid_ml->v;
         medge[new_eidx].v2 = first_valid_ml->v;
         /* DO NOT change newe mapping,
@@ -566,25 +574,25 @@ Mesh *BKE_mesh_merge_verts(Mesh *mesh,
       mesh, STACK_SIZE(mvert), STACK_SIZE(medge), 0, STACK_SIZE(mloop), STACK_SIZE(mpoly));
 
   /* Update edge indices and copy customdata. */
-  med = medge;
-  for (i = 0; i < result->totedge; i++, med++) {
-    BLI_assert(newv[med->v1] != -1);
-    med->v1 = newv[med->v1];
-    BLI_assert(newv[med->v2] != -1);
-    med->v2 = newv[med->v2];
+  MEdge *new_med = medge;
+  for (i = 0; i < result->totedge; i++, new_med++) {
+    BLI_assert(newv[new_med->v1] != -1);
+    new_med->v1 = newv[new_med->v1];
+    BLI_assert(newv[new_med->v2] != -1);
+    new_med->v2 = newv[new_med->v2];
 
     /* Can happen in case vtargetmap contains some double chains, we do not support that. */
-    BLI_assert(med->v1 != med->v2);
+    BLI_assert(new_med->v1 != new_med->v2);
 
     CustomData_copy_data(&mesh->edata, &result->edata, olde[i], i, 1);
   }
 
   /* Update loop indices and copy customdata. */
-  ml = mloop;
-  for (i = 0; i < result->totloop; i++, ml++) {
+  MLoop *new_ml = mloop;
+  for (i = 0; i < result->totloop; i++, new_ml++) {
     /* Edge remapping has already be done in main loop handling part above. */
-    BLI_assert(newv[ml->v] != -1);
-    ml->v = newv[ml->v];
+    BLI_assert(newv[new_ml->v] != -1);
+    new_ml->v = newv[new_ml->v];
 
     CustomData_copy_data(&mesh->ldata, &result->ldata, oldl[i], i, 1);
   }
@@ -603,16 +611,16 @@ Mesh *BKE_mesh_merge_verts(Mesh *mesh,
 
   /* Copy over data. #CustomData_add_layer can do this, need to look it up. */
   if (STACK_SIZE(mvert)) {
-    memcpy(result->mvert, mvert, sizeof(MVert) * STACK_SIZE(mvert));
+    memcpy(BKE_mesh_verts_for_write(result), mvert, sizeof(MVert) * STACK_SIZE(mvert));
   }
   if (STACK_SIZE(medge)) {
-    memcpy(result->medge, medge, sizeof(MEdge) * STACK_SIZE(medge));
+    memcpy(BKE_mesh_edges_for_write(result), medge, sizeof(MEdge) * STACK_SIZE(medge));
   }
   if (STACK_SIZE(mloop)) {
-    memcpy(result->mloop, mloop, sizeof(MLoop) * STACK_SIZE(mloop));
+    memcpy(BKE_mesh_loops_for_write(result), mloop, sizeof(MLoop) * STACK_SIZE(mloop));
   }
   if (STACK_SIZE(mpoly)) {
-    memcpy(result->mpoly, mpoly, sizeof(MPoly) * STACK_SIZE(mpoly));
+    memcpy(BKE_mesh_polys_for_write(result), mpoly, sizeof(MPoly) * STACK_SIZE(mpoly));
   }
 
   MEM_freeN(mvert);
diff --git a/source/blender/blenkernel/intern/mesh_merge_customdata.cc b/source/blender/blenkernel/intern/mesh_merge_customdata.cc
index adaf378ed27..f7936d8a4da 100644
--- a/source/blender/blenkernel/intern/mesh_merge_customdata.cc
+++ b/source/blender/blenkernel/intern/mesh_merge_customdata.cc
@@ -33,11 +33,11 @@ static int compare_v2_classify(const float uv_a[2], const float uv_b[2])
   if (uv_a[0] == uv_b[0] && uv_a[1] == uv_b[1]) {
     return CMP_EQUAL;
   }
-  /* Note that the ULP value is the primary value used to compare relative values
-   * as the absolute value doesn't account for float precision at difference scales.
+  /* NOTE(@campbellbarton): that the ULP value is the primary value used to compare relative
+   * values as the absolute value doesn't account for float precision at difference scales.
    * - For subdivision-surface ULP of 3 is sufficient,
    *   although this value is extremely small.
-   * - For bevel the URL of 12 is sufficient to merge UV's that appear to be connected
+   * - For bevel the ULP of 12 is sufficient to merge UV's that appear to be connected
    *   with bevel on Suzanne beveled 15% with 6 segments.
    *
    * These values could be tweaked but should be kept on the small side to prevent
@@ -113,8 +113,13 @@ void BKE_mesh_merge_customdata_for_apply_modifier(Mesh *me)
 
   int *vert_map_mem;
   struct MeshElemMap *vert_to_loop;
-  BKE_mesh_vert_loop_map_create(
-      &vert_to_loop, &vert_map_mem, me->mpoly, me->mloop, me->totvert, me->totpoly, me->totloop);
+  BKE_mesh_vert_loop_map_create(&vert_to_loop,
+                                &vert_map_mem,
+                                BKE_mesh_polys(me),
+                                BKE_mesh_loops(me),
+                                me->totvert,
+                                me->totpoly,
+                                me->totloop);
 
   Vector mloopuv_layers;
   mloopuv_layers.reserve(mloopuv_layers_num);
diff --git a/source/blender/blenkernel/intern/mesh_mirror.c b/source/blender/blenkernel/intern/mesh_mirror.c
index 715a1c9daf9..261bc3d150b 100644
--- a/source/blender/blenkernel/intern/mesh_mirror.c
+++ b/source/blender/blenkernel/intern/mesh_mirror.c
@@ -208,17 +208,17 @@ Mesh *BKE_mesh_mirror_apply_mirror_on_axis_for_modifier(MirrorModifierData *mmd,
   CustomData_copy_data(&mesh->ldata, &result->ldata, 0, 0, maxLoops);
   CustomData_copy_data(&mesh->pdata, &result->pdata, 0, 0, maxPolys);
 
-  /* Subsurf for eg won't have mesh data in the custom-data arrays.
-   * now add mvert/medge/mpoly layers. */
+  /* Subdivision-surface for eg won't have mesh data in the custom-data arrays.
+   * Now add #MVert/#MEdge/#MPoly layers. */
   if (!CustomData_has_layer(&mesh->vdata, CD_MVERT)) {
-    memcpy(result->mvert, mesh->mvert, sizeof(*result->mvert) * mesh->totvert);
+    memcpy(BKE_mesh_verts_for_write(result), BKE_mesh_verts(mesh), sizeof(MVert) * mesh->totvert);
   }
   if (!CustomData_has_layer(&mesh->edata, CD_MEDGE)) {
-    memcpy(result->medge, mesh->medge, sizeof(*result->medge) * mesh->totedge);
+    memcpy(BKE_mesh_edges_for_write(result), BKE_mesh_edges(mesh), sizeof(MEdge) * mesh->totedge);
   }
   if (!CustomData_has_layer(&mesh->pdata, CD_MPOLY)) {
-    memcpy(result->mloop, mesh->mloop, sizeof(*result->mloop) * mesh->totloop);
-    memcpy(result->mpoly, mesh->mpoly, sizeof(*result->mpoly) * mesh->totpoly);
+    memcpy(BKE_mesh_loops_for_write(result), BKE_mesh_loops(mesh), sizeof(MLoop) * mesh->totloop);
+    memcpy(BKE_mesh_polys_for_write(result), BKE_mesh_polys(mesh), sizeof(MPoly) * mesh->totpoly);
   }
 
   /* Copy custom-data to new geometry,
@@ -237,7 +237,7 @@ Mesh *BKE_mesh_mirror_apply_mirror_on_axis_for_modifier(MirrorModifierData *mmd,
   }
 
   /* mirror vertex coordinates */
-  mv_prev = result->mvert;
+  mv_prev = BKE_mesh_verts_for_write(result);
   mv = mv_prev + maxVerts;
   for (i = 0; i < maxVerts; i++, mv++, mv_prev++) {
     mul_m4_v3(mtx, mv->co);
@@ -304,15 +304,15 @@ Mesh *BKE_mesh_mirror_apply_mirror_on_axis_for_modifier(MirrorModifierData *mmd,
   }
 
   /* adjust mirrored edge vertex indices */
-  me = result->medge + maxEdges;
+  me = BKE_mesh_edges_for_write(result) + maxEdges;
   for (i = 0; i < maxEdges; i++, me++) {
     me->v1 += maxVerts;
     me->v2 += maxVerts;
   }
 
   /* adjust mirrored poly loopstart indices, and reverse loop order (normals) */
-  mp = result->mpoly + maxPolys;
-  ml = result->mloop;
+  mp = BKE_mesh_polys_for_write(result) + maxPolys;
+  ml = BKE_mesh_loops_for_write(result);
   for (i = 0; i < maxPolys; i++, mp++) {
     MLoop *ml2;
     int j, e;
@@ -341,7 +341,7 @@ Mesh *BKE_mesh_mirror_apply_mirror_on_axis_for_modifier(MirrorModifierData *mmd,
   }
 
   /* adjust mirrored loop vertex and edge indices */
-  ml = result->mloop + maxLoops;
+  ml = BKE_mesh_loops_for_write(result) + maxLoops;
   for (i = 0; i < maxLoops; i++, ml++) {
     ml->v += maxVerts;
     ml->e += maxEdges;
@@ -405,15 +405,15 @@ Mesh *BKE_mesh_mirror_apply_mirror_on_axis_for_modifier(MirrorModifierData *mmd,
 
     /* calculate custom normals into loop_normals, then mirror first half into second half */
 
-    BKE_mesh_normals_loop_split(result->mvert,
+    BKE_mesh_normals_loop_split(BKE_mesh_verts(result),
                                 BKE_mesh_vertex_normals_ensure(result),
                                 result->totvert,
-                                result->medge,
+                                BKE_mesh_edges(result),
                                 result->totedge,
-                                result->mloop,
+                                BKE_mesh_loops(result),
                                 loop_normals,
                                 totloop,
-                                result->mpoly,
+                                BKE_mesh_polys(result),
                                 BKE_mesh_poly_normals_ensure(result),
                                 totpoly,
                                 true,
@@ -423,9 +423,10 @@ Mesh *BKE_mesh_mirror_apply_mirror_on_axis_for_modifier(MirrorModifierData *mmd,
                                 NULL);
 
     /* mirroring has to account for loops being reversed in polys in second half */
-    mp = result->mpoly;
+    MPoly *result_polys = BKE_mesh_polys_for_write(result);
+    mp = result_polys;
     for (i = 0; i < maxPolys; i++, mp++) {
-      MPoly *mpmirror = result->mpoly + maxPolys + i;
+      MPoly *mpmirror = result_polys + maxPolys + i;
       int j;
 
       for (j = mp->loopstart; j < mp->loopstart + mp->totloop; j++) {
@@ -446,11 +447,10 @@ Mesh *BKE_mesh_mirror_apply_mirror_on_axis_for_modifier(MirrorModifierData *mmd,
 
   /* handle vgroup stuff */
   if ((mmd->flag & MOD_MIR_VGROUP) && CustomData_has_layer(&result->vdata, CD_MDEFORMVERT)) {
-    MDeformVert *dvert = (MDeformVert *)CustomData_get_layer(&result->vdata, CD_MDEFORMVERT) +
-                         maxVerts;
+    MDeformVert *dvert = BKE_mesh_deform_verts_for_write(result) + maxVerts;
     int *flip_map = NULL, flip_map_len = 0;
 
-    flip_map = BKE_object_defgroup_flip_map(ob, &flip_map_len, false);
+    flip_map = BKE_object_defgroup_flip_map(ob, false, &flip_map_len);
 
     if (flip_map) {
       for (i = 0; i < maxVerts; dvert++, i++) {
diff --git a/source/blender/blenkernel/intern/mesh_normals.cc b/source/blender/blenkernel/intern/mesh_normals.cc
index 2366b7526a1..21dd39586ec 100644
--- a/source/blender/blenkernel/intern/mesh_normals.cc
+++ b/source/blender/blenkernel/intern/mesh_normals.cc
@@ -17,8 +17,7 @@
 #include "DNA_meshdata_types.h"
 
 #include "BLI_alloca.h"
-#include "BLI_bitmap.h"
-
+#include "BLI_bit_vector.hh"
 #include "BLI_linklist.h"
 #include "BLI_linklist_stack.h"
 #include "BLI_math.h"
@@ -37,6 +36,8 @@
 
 #include "atomic_ops.h"
 
+using blender::BitVector;
+using blender::MutableSpan;
 using blender::Span;
 
 // #define DEBUG_TIME
@@ -368,16 +369,19 @@ const float (*BKE_mesh_vertex_normals_ensure(const Mesh *mesh))[3]
   /* Isolate task because a mutex is locked and computing normals is multi-threaded. */
   blender::threading::isolate_task([&]() {
     Mesh &mesh_mutable = *const_cast(mesh);
+    const Span verts = mesh_mutable.verts();
+    const Span polys = mesh_mutable.polys();
+    const Span loops = mesh_mutable.loops();
 
     vert_normals = BKE_mesh_vertex_normals_for_write(&mesh_mutable);
     poly_normals = BKE_mesh_poly_normals_for_write(&mesh_mutable);
 
-    BKE_mesh_calc_normals_poly_and_vertex(mesh_mutable.mvert,
-                                          mesh_mutable.totvert,
-                                          mesh_mutable.mloop,
-                                          mesh_mutable.totloop,
-                                          mesh_mutable.mpoly,
-                                          mesh_mutable.totpoly,
+    BKE_mesh_calc_normals_poly_and_vertex(verts.data(),
+                                          verts.size(),
+                                          loops.data(),
+                                          loops.size(),
+                                          polys.data(),
+                                          polys.size(),
                                           poly_normals,
                                           vert_normals);
 
@@ -413,15 +417,18 @@ const float (*BKE_mesh_poly_normals_ensure(const Mesh *mesh))[3]
   /* Isolate task because a mutex is locked and computing normals is multi-threaded. */
   blender::threading::isolate_task([&]() {
     Mesh &mesh_mutable = *const_cast(mesh);
+    const Span verts = mesh_mutable.verts();
+    const Span polys = mesh_mutable.polys();
+    const Span loops = mesh_mutable.loops();
 
     poly_normals = BKE_mesh_poly_normals_for_write(&mesh_mutable);
 
-    BKE_mesh_calc_normals_poly(mesh_mutable.mvert,
-                               mesh_mutable.totvert,
-                               mesh_mutable.mloop,
-                               mesh_mutable.totloop,
-                               mesh_mutable.mpoly,
-                               mesh_mutable.totpoly,
+    BKE_mesh_calc_normals_poly(verts.data(),
+                               verts.size(),
+                               loops.data(),
+                               loops.size(),
+                               polys.data(),
+                               polys.size(),
                                poly_normals);
 
     BKE_mesh_poly_normals_clear_dirty(&mesh_mutable);
@@ -849,7 +856,10 @@ static void mesh_edges_sharp_tag(LoopSplitTaskDataCommon *data,
   int(*edge_to_loops)[2] = data->edge_to_loops;
   int *loop_to_poly = data->loop_to_poly;
 
-  BLI_bitmap *sharp_edges = do_sharp_edges_tag ? BLI_BITMAP_NEW(numEdges, __func__) : nullptr;
+  BitVector sharp_edges;
+  if (do_sharp_edges_tag) {
+    sharp_edges.resize(numEdges, false);
+  }
 
   const MPoly *mp;
   int mp_index;
@@ -901,7 +911,7 @@ static void mesh_edges_sharp_tag(LoopSplitTaskDataCommon *data,
           /* We want to avoid tagging edges as sharp when it is already defined as such by
            * other causes than angle threshold. */
           if (do_sharp_edges_tag && is_angle_sharp) {
-            BLI_BITMAP_SET(sharp_edges, ml_curr->e, true);
+            sharp_edges[ml_curr->e].set();
           }
         }
         else {
@@ -915,7 +925,7 @@ static void mesh_edges_sharp_tag(LoopSplitTaskDataCommon *data,
         /* We want to avoid tagging edges as sharp when it is already defined as such by
          * other causes than angle threshold. */
         if (do_sharp_edges_tag) {
-          BLI_BITMAP_SET(sharp_edges, ml_curr->e, false);
+          sharp_edges[ml_curr->e].reset();
         }
       }
       /* Else, edge is already 'disqualified' (i.e. sharp)! */
@@ -927,12 +937,10 @@ static void mesh_edges_sharp_tag(LoopSplitTaskDataCommon *data,
     MEdge *me;
     int me_index;
     for (me = (MEdge *)medges, me_index = 0; me_index < numEdges; me++, me_index++) {
-      if (BLI_BITMAP_TEST(sharp_edges, me_index)) {
+      if (sharp_edges[me_index]) {
         me->flag |= ME_SHARP;
       }
     }
-
-    MEM_freeN(sharp_edges);
   }
 }
 
@@ -940,9 +948,9 @@ void BKE_edges_sharp_from_angle_set(const struct MVert *mverts,
                                     const int UNUSED(numVerts),
                                     struct MEdge *medges,
                                     const int numEdges,
-                                    struct MLoop *mloops,
+                                    const struct MLoop *mloops,
                                     const int numLoops,
-                                    struct MPoly *mpolys,
+                                    const struct MPoly *mpolys,
                                     const float (*polynors)[3],
                                     const int numPolys,
                                     const float split_angle)
@@ -1354,7 +1362,7 @@ static bool loop_split_generator_check_cyclic_smooth_fan(const MLoop *mloops,
                                                          const int (*edge_to_loops)[2],
                                                          const int *loop_to_poly,
                                                          const int *e2l_prev,
-                                                         BLI_bitmap *skip_loops,
+                                                         BitVector<> &skip_loops,
                                                          const MLoop *ml_curr,
                                                          const MLoop *ml_prev,
                                                          const int ml_curr_index,
@@ -1383,8 +1391,8 @@ static bool loop_split_generator_check_cyclic_smooth_fan(const MLoop *mloops,
   BLI_assert(mlfan_vert_index >= 0);
   BLI_assert(mpfan_curr_index >= 0);
 
-  BLI_assert(!BLI_BITMAP_TEST(skip_loops, mlfan_vert_index));
-  BLI_BITMAP_ENABLE(skip_loops, mlfan_vert_index);
+  BLI_assert(!skip_loops[mlfan_vert_index]);
+  skip_loops[mlfan_vert_index].set();
 
   while (true) {
     /* Find next loop of the smooth fan. */
@@ -1405,7 +1413,7 @@ static bool loop_split_generator_check_cyclic_smooth_fan(const MLoop *mloops,
       return false;
     }
     /* Smooth loop/edge. */
-    if (BLI_BITMAP_TEST(skip_loops, mlfan_vert_index)) {
+    if (skip_loops[mlfan_vert_index]) {
       if (mlfan_vert_index == ml_curr_index) {
         /* We walked around a whole cyclic smooth fan without finding any already-processed loop,
          * means we can use initial `ml_curr` / `ml_prev` edge as start for this smooth fan. */
@@ -1416,7 +1424,7 @@ static bool loop_split_generator_check_cyclic_smooth_fan(const MLoop *mloops,
     }
 
     /* We can skip it in future, and keep checking the smooth fan. */
-    BLI_BITMAP_ENABLE(skip_loops, mlfan_vert_index);
+    skip_loops[mlfan_vert_index].set();
   }
 }
 
@@ -1440,7 +1448,7 @@ static void loop_split_generator(TaskPool *pool, LoopSplitTaskDataCommon *common
   int ml_curr_index;
   int ml_prev_index;
 
-  BLI_bitmap *skip_loops = BLI_BITMAP_NEW(numLoops, __func__);
+  BitVector<> skip_loops(numLoops, false);
 
   LoopSplitTaskData *data_buff = nullptr;
   int data_idx = 0;
@@ -1482,7 +1490,7 @@ static void loop_split_generator(TaskPool *pool, LoopSplitTaskDataCommon *common
              ml_curr->e,
              ml_curr->v,
              IS_EDGE_SHARP(e2l_curr),
-             BLI_BITMAP_TEST_BOOL(skip_loops, ml_curr_index));
+             skip_loops[ml_curr_index]);
 #endif
 
       /* A smooth edge, we have to check for cyclic smooth fan case.
@@ -1495,7 +1503,7 @@ static void loop_split_generator(TaskPool *pool, LoopSplitTaskDataCommon *common
        * However, this would complicate the code, add more memory usage, and despite its logical
        * complexity, #loop_manifold_fan_around_vert_next() is quite cheap in term of CPU cycles,
        * so really think it's not worth it. */
-      if (!IS_EDGE_SHARP(e2l_curr) && (BLI_BITMAP_TEST(skip_loops, ml_curr_index) ||
+      if (!IS_EDGE_SHARP(e2l_curr) && (skip_loops[ml_curr_index] ||
                                        !loop_split_generator_check_cyclic_smooth_fan(mloops,
                                                                                      mpolys,
                                                                                      edge_to_loops,
@@ -1590,7 +1598,6 @@ static void loop_split_generator(TaskPool *pool, LoopSplitTaskDataCommon *common
   if (edge_vectors) {
     BLI_stack_free(edge_vectors);
   }
-  MEM_freeN(skip_loops);
 
 #ifdef DEBUG_TIME
   TIMEIT_END_AVERAGED(loop_split_generator);
@@ -1600,12 +1607,12 @@ static void loop_split_generator(TaskPool *pool, LoopSplitTaskDataCommon *common
 void BKE_mesh_normals_loop_split(const MVert *mverts,
                                  const float (*vert_normals)[3],
                                  const int UNUSED(numVerts),
-                                 MEdge *medges,
+                                 const MEdge *medges,
                                  const int numEdges,
-                                 MLoop *mloops,
+                                 const MLoop *mloops,
                                  float (*r_loopnors)[3],
                                  const int numLoops,
-                                 MPoly *mpolys,
+                                 const MPoly *mpolys,
                                  const float (*polynors)[3],
                                  const int numPolys,
                                  const bool use_split_normals,
@@ -1628,7 +1635,7 @@ void BKE_mesh_normals_loop_split(const MVert *mverts,
     int mp_index;
 
     for (mp_index = 0; mp_index < numPolys; mp_index++) {
-      MPoly *mp = &mpolys[mp_index];
+      const MPoly *mp = &mpolys[mp_index];
       int ml_index = mp->loopstart;
       const int ml_index_end = ml_index + mp->totloop;
       const bool is_poly_flat = ((mp->flag & ME_SMOOTH) == 0);
@@ -1755,10 +1762,10 @@ static void mesh_normals_loop_custom_set(const MVert *mverts,
                                          const int numVerts,
                                          MEdge *medges,
                                          const int numEdges,
-                                         MLoop *mloops,
+                                         const MLoop *mloops,
                                          float (*r_custom_loopnors)[3],
                                          const int numLoops,
-                                         MPoly *mpolys,
+                                         const MPoly *mpolys,
                                          const float (*polynors)[3],
                                          const int numPolys,
                                          short (*r_clnors_data)[2],
@@ -1771,7 +1778,7 @@ static void mesh_normals_loop_custom_set(const MVert *mverts,
    * (and perhaps from some editing tools later?).
    * So better to keep some simplicity here, and just call #BKE_mesh_normals_loop_split() twice! */
   MLoopNorSpaceArray lnors_spacearr = {nullptr};
-  BLI_bitmap *done_loops = BLI_BITMAP_NEW((size_t)numLoops, __func__);
+  BitVector<> done_loops(numLoops, false);
   float(*lnors)[3] = (float(*)[3])MEM_calloc_arrayN((size_t)numLoops, sizeof(*lnors), __func__);
   int *loop_to_poly = (int *)MEM_malloc_arrayN((size_t)numLoops, sizeof(int), __func__);
   /* In this case we always consider split nors as ON,
@@ -1829,14 +1836,14 @@ static void mesh_normals_loop_custom_set(const MVert *mverts,
         /* This should not happen in theory, but in some rare case (probably ugly geometry)
          * we can get some nullptr loopspacearr at this point. :/
          * Maybe we should set those loops' edges as sharp? */
-        BLI_BITMAP_ENABLE(done_loops, i);
+        done_loops[i].set();
         if (G.debug & G_DEBUG) {
           printf("WARNING! Getting invalid nullptr loop space for loop %d!\n", i);
         }
         continue;
       }
 
-      if (!BLI_BITMAP_TEST(done_loops, i)) {
+      if (!done_loops[i]) {
         /* Notes:
          * - In case of mono-loop smooth fan, we have nothing to do.
          * - Loops in this linklist are ordered (in reversed order compared to how they were
@@ -1847,17 +1854,17 @@ static void mesh_normals_loop_custom_set(const MVert *mverts,
          *   to avoid small differences adding up into a real big one in the end!
          */
         if (lnors_spacearr.lspacearr[i]->flags & MLNOR_SPACE_IS_SINGLE) {
-          BLI_BITMAP_ENABLE(done_loops, i);
+          done_loops[i].set();
           continue;
         }
 
         LinkNode *loops = lnors_spacearr.lspacearr[i]->loops;
-        MLoop *prev_ml = nullptr;
+        const MLoop *prev_ml = nullptr;
         const float *org_nor = nullptr;
 
         while (loops) {
           const int lidx = POINTER_AS_INT(loops->link);
-          MLoop *ml = &mloops[lidx];
+          const MLoop *ml = &mloops[lidx];
           const int nidx = lidx;
           float *nor = r_custom_loopnors[nidx];
 
@@ -1879,7 +1886,7 @@ static void mesh_normals_loop_custom_set(const MVert *mverts,
 
           prev_ml = ml;
           loops = loops->next;
-          BLI_BITMAP_ENABLE(done_loops, lidx);
+          done_loops[lidx].set();
         }
 
         /* We also have to check between last and first loops,
@@ -1889,7 +1896,7 @@ static void mesh_normals_loop_custom_set(const MVert *mverts,
         loops = lnors_spacearr.lspacearr[i]->loops;
         if (loops && org_nor) {
           const int lidx = POINTER_AS_INT(loops->link);
-          MLoop *ml = &mloops[lidx];
+          const MLoop *ml = &mloops[lidx];
           const int nidx = lidx;
           float *nor = r_custom_loopnors[nidx];
 
@@ -1923,14 +1930,14 @@ static void mesh_normals_loop_custom_set(const MVert *mverts,
                                 loop_to_poly);
   }
   else {
-    BLI_bitmap_set_all(done_loops, true, (size_t)numLoops);
+    done_loops.fill(true);
   }
 
   /* And we just have to convert plain object-space custom normals to our
    * lnor space-encoded ones. */
   for (int i = 0; i < numLoops; i++) {
     if (!lnors_spacearr.lspacearr[i]) {
-      BLI_BITMAP_DISABLE(done_loops, i);
+      done_loops[i].reset();
       if (G.debug & G_DEBUG) {
         printf("WARNING! Still getting invalid nullptr loop space in second loop for loop %d!\n",
                i);
@@ -1938,7 +1945,7 @@ static void mesh_normals_loop_custom_set(const MVert *mverts,
       continue;
     }
 
-    if (BLI_BITMAP_TEST_BOOL(done_loops, i)) {
+    if (done_loops[i]) {
       /* Note we accumulate and average all custom normals in current smooth fan,
        * to avoid getting different clnors data (tiny differences in plain custom normals can
        * give rather huge differences in computed 2D factors). */
@@ -1949,7 +1956,7 @@ static void mesh_normals_loop_custom_set(const MVert *mverts,
         float *nor = r_custom_loopnors[nidx];
 
         BKE_lnor_space_custom_normal_to_data(lnors_spacearr.lspacearr[i], nor, r_clnors_data[i]);
-        BLI_BITMAP_DISABLE(done_loops, i);
+        done_loops[i].reset();
       }
       else {
         int avg_nor_count = 0;
@@ -1967,7 +1974,7 @@ static void mesh_normals_loop_custom_set(const MVert *mverts,
           BLI_SMALLSTACK_PUSH(clnors_data, (short *)r_clnors_data[lidx]);
 
           loops = loops->next;
-          BLI_BITMAP_DISABLE(done_loops, lidx);
+          done_loops[lidx].reset();
         }
 
         mul_v3_fl(avg_nor, 1.0f / (float)avg_nor_count);
@@ -1983,7 +1990,6 @@ static void mesh_normals_loop_custom_set(const MVert *mverts,
 
   MEM_freeN(lnors);
   MEM_freeN(loop_to_poly);
-  MEM_freeN(done_loops);
   BKE_lnor_spacearr_free(&lnors_spacearr);
 }
 
@@ -1992,10 +1998,10 @@ void BKE_mesh_normals_loop_custom_set(const MVert *mverts,
                                       const int numVerts,
                                       MEdge *medges,
                                       const int numEdges,
-                                      MLoop *mloops,
+                                      const MLoop *mloops,
                                       float (*r_custom_loopnors)[3],
                                       const int numLoops,
-                                      MPoly *mpolys,
+                                      const MPoly *mpolys,
                                       const float (*polynors)[3],
                                       const int numPolys,
                                       short (*r_clnors_data)[2])
@@ -2015,18 +2021,18 @@ void BKE_mesh_normals_loop_custom_set(const MVert *mverts,
                                false);
 }
 
-void BKE_mesh_normals_loop_custom_from_vertices_set(const MVert *mverts,
-                                                    const float (*vert_normals)[3],
-                                                    float (*r_custom_vertnors)[3],
-                                                    const int numVerts,
-                                                    MEdge *medges,
-                                                    const int numEdges,
-                                                    MLoop *mloops,
-                                                    const int numLoops,
-                                                    MPoly *mpolys,
-                                                    const float (*polynors)[3],
-                                                    const int numPolys,
-                                                    short (*r_clnors_data)[2])
+void BKE_mesh_normals_loop_custom_from_verts_set(const MVert *mverts,
+                                                 const float (*vert_normals)[3],
+                                                 float (*r_custom_vertnors)[3],
+                                                 const int numVerts,
+                                                 MEdge *medges,
+                                                 const int numEdges,
+                                                 const MLoop *mloops,
+                                                 const int numLoops,
+                                                 const MPoly *mpolys,
+                                                 const float (*polynors)[3],
+                                                 const int numPolys,
+                                                 short (*r_clnors_data)[2])
 {
   mesh_normals_loop_custom_set(mverts,
                                vert_normals,
@@ -2054,20 +2060,24 @@ static void mesh_set_custom_normals(Mesh *mesh, float (*r_custom_nors)[3], const
   }
   else {
     clnors = (short(*)[2])CustomData_add_layer(
-        &mesh->ldata, CD_CUSTOMLOOPNORMAL, CD_CALLOC, nullptr, numloops);
+        &mesh->ldata, CD_CUSTOMLOOPNORMAL, CD_SET_DEFAULT, nullptr, numloops);
   }
+  const Span verts = mesh->verts();
+  MutableSpan edges = mesh->edges_for_write();
+  const Span polys = mesh->polys();
+  const Span loops = mesh->loops();
 
-  mesh_normals_loop_custom_set(mesh->mvert,
+  mesh_normals_loop_custom_set(verts.data(),
                                BKE_mesh_vertex_normals_ensure(mesh),
-                               mesh->totvert,
-                               mesh->medge,
-                               mesh->totedge,
-                               mesh->mloop,
+                               verts.size(),
+                               edges.data(),
+                               edges.size(),
+                               loops.data(),
                                r_custom_nors,
-                               mesh->totloop,
-                               mesh->mpoly,
+                               loops.size(),
+                               polys.data(),
                                BKE_mesh_poly_normals_ensure(mesh),
-                               mesh->totpoly,
+                               polys.size(),
                                clnors,
                                use_vertices);
 }
@@ -2077,7 +2087,7 @@ void BKE_mesh_set_custom_normals(Mesh *mesh, float (*r_custom_loopnors)[3])
   mesh_set_custom_normals(mesh, r_custom_loopnors, false);
 }
 
-void BKE_mesh_set_custom_normals_from_vertices(Mesh *mesh, float (*r_custom_vertnors)[3])
+void BKE_mesh_set_custom_normals_from_verts(Mesh *mesh, float (*r_custom_vertnors)[3])
 {
   mesh_set_custom_normals(mesh, r_custom_vertnors, true);
 }
diff --git a/source/blender/blenkernel/intern/mesh_remap.c b/source/blender/blenkernel/intern/mesh_remap.c
index 3a37c29c1d0..d63d064eb3c 100644
--- a/source/blender/blenkernel/intern/mesh_remap.c
+++ b/source/blender/blenkernel/intern/mesh_remap.c
@@ -312,15 +312,10 @@ void BKE_mesh_remap_calc_source_cddata_masks_from_map_modes(const int UNUSED(ver
 {
   /* vert, edge and poly mapping modes never need extra cddata from source object. */
   const bool need_lnors_src = (loop_mode & MREMAP_USE_LOOP) && (loop_mode & MREMAP_USE_NORMAL);
-  const bool need_pnors_src = need_lnors_src ||
-                              ((loop_mode & MREMAP_USE_POLY) && (loop_mode & MREMAP_USE_NORMAL));
 
   if (need_lnors_src) {
     r_cddata_mask->lmask |= CD_MASK_NORMAL;
   }
-  if (need_pnors_src) {
-    r_cddata_mask->pmask |= CD_MASK_NORMAL;
-  }
 }
 
 void BKE_mesh_remap_init(MeshPairRemap *map, const int items_num)
@@ -382,7 +377,7 @@ void BKE_mesh_remap_item_define_invalid(MeshPairRemap *map, const int index)
 }
 
 static int mesh_remap_interp_poly_data_get(const MPoly *mp,
-                                           MLoop *mloops,
+                                           const MLoop *mloops,
                                            const float (*vcos_src)[3],
                                            const float point[3],
                                            size_t *buff_size,
@@ -393,7 +388,7 @@ static int mesh_remap_interp_poly_data_get(const MPoly *mp,
                                            const bool do_weights,
                                            int *r_closest_index)
 {
-  MLoop *ml;
+  const MLoop *ml;
   float(*vco)[3];
   float ref_dist_sq = FLT_MAX;
   int *index;
@@ -525,7 +520,7 @@ void BKE_mesh_remap_calc_verts_from_mesh(const int mode,
       }
     }
     else if (ELEM(mode, MREMAP_MODE_VERT_EDGE_NEAREST, MREMAP_MODE_VERT_EDGEINTERP_NEAREST)) {
-      MEdge *edges_src = me_src->medge;
+      const MEdge *edges_src = BKE_mesh_edges(me_src);
       float(*vcos_src)[3] = BKE_mesh_vert_coords_alloc(me_src, NULL);
 
       BKE_bvhtree_from_mesh_get(&treedata, me_src, BVHTREE_FROM_EDGES, 2);
@@ -541,7 +536,7 @@ void BKE_mesh_remap_calc_verts_from_mesh(const int mode,
 
         if (mesh_remap_bvhtree_query_nearest(
                 &treedata, &nearest, tmp_co, max_dist_sq, &hit_dist)) {
-          MEdge *me = &edges_src[nearest.index];
+          const MEdge *me = &edges_src[nearest.index];
           const float *v1cos = vcos_src[me->v1];
           const float *v2cos = vcos_src[me->v2];
 
@@ -578,8 +573,8 @@ void BKE_mesh_remap_calc_verts_from_mesh(const int mode,
                   MREMAP_MODE_VERT_POLY_NEAREST,
                   MREMAP_MODE_VERT_POLYINTERP_NEAREST,
                   MREMAP_MODE_VERT_POLYINTERP_VNORPROJ)) {
-      MPoly *polys_src = me_src->mpoly;
-      MLoop *loops_src = me_src->mloop;
+      const MPoly *polys_src = BKE_mesh_polys(me_src);
+      const MLoop *loops_src = BKE_mesh_loops(me_src);
       float(*vcos_src)[3] = BKE_mesh_vert_coords_alloc(me_src, NULL);
       const float(*vert_normals_dst)[3] = BKE_mesh_vertex_normals_ensure(me_dst);
 
@@ -604,7 +599,7 @@ void BKE_mesh_remap_calc_verts_from_mesh(const int mode,
           if (mesh_remap_bvhtree_query_raycast(
                   &treedata, &rayhit, tmp_co, tmp_no, ray_radius, max_dist, &hit_dist)) {
             const MLoopTri *lt = &treedata.looptri[rayhit.index];
-            MPoly *mp_src = &polys_src[lt->poly];
+            const MPoly *mp_src = &polys_src[lt->poly];
             const int sources_num = mesh_remap_interp_poly_data_get(mp_src,
                                                                     loops_src,
                                                                     (const float(*)[3])vcos_src,
@@ -639,7 +634,7 @@ void BKE_mesh_remap_calc_verts_from_mesh(const int mode,
           if (mesh_remap_bvhtree_query_nearest(
                   &treedata, &nearest, tmp_co, max_dist_sq, &hit_dist)) {
             const MLoopTri *lt = &treedata.looptri[nearest.index];
-            MPoly *mp = &polys_src[lt->poly];
+            const MPoly *mp = &polys_src[lt->poly];
 
             if (mode == MREMAP_MODE_VERT_POLY_NEAREST) {
               int index;
@@ -731,7 +726,7 @@ void BKE_mesh_remap_calc_edges_from_mesh(const int mode,
     if (mode == MREMAP_MODE_EDGE_VERT_NEAREST) {
       const int num_verts_src = me_src->totvert;
       const int num_edges_src = me_src->totedge;
-      MEdge *edges_src = me_src->medge;
+      const MEdge *edges_src = BKE_mesh_edges(me_src);
       float(*vcos_src)[3] = BKE_mesh_vert_coords_alloc(me_src, NULL);
 
       MeshElemMap *vert_to_edge_src_map;
@@ -802,7 +797,7 @@ void BKE_mesh_remap_calc_edges_from_mesh(const int mode,
           k = vert_to_edge_src_map[vidx_src].count;
 
           for (; k--; eidx_src++) {
-            MEdge *e_src = &edges_src[*eidx_src];
+            const MEdge *e_src = &edges_src[*eidx_src];
             const float *other_co_src = vcos_src[BKE_mesh_edge_other_vert(e_src, vidx_src)];
             const float *other_co_dst =
                 verts_dst[BKE_mesh_edge_other_vert(e_dst, (int)vidx_dst)].co;
@@ -878,9 +873,9 @@ void BKE_mesh_remap_calc_edges_from_mesh(const int mode,
       }
     }
     else if (mode == MREMAP_MODE_EDGE_POLY_NEAREST) {
-      MEdge *edges_src = me_src->medge;
-      MPoly *polys_src = me_src->mpoly;
-      MLoop *loops_src = me_src->mloop;
+      const MEdge *edges_src = BKE_mesh_edges(me_src);
+      const MPoly *polys_src = BKE_mesh_polys(me_src);
+      const MLoop *loops_src = BKE_mesh_loops(me_src);
       float(*vcos_src)[3] = BKE_mesh_vert_coords_alloc(me_src, NULL);
 
       BKE_bvhtree_from_mesh_get(&treedata, me_src, BVHTREE_FROM_LOOPTRI, 2);
@@ -896,14 +891,14 @@ void BKE_mesh_remap_calc_edges_from_mesh(const int mode,
         if (mesh_remap_bvhtree_query_nearest(
                 &treedata, &nearest, tmp_co, max_dist_sq, &hit_dist)) {
           const MLoopTri *lt = &treedata.looptri[nearest.index];
-          MPoly *mp_src = &polys_src[lt->poly];
-          MLoop *ml_src = &loops_src[mp_src->loopstart];
+          const MPoly *mp_src = &polys_src[lt->poly];
+          const MLoop *ml_src = &loops_src[mp_src->loopstart];
           int nloops = mp_src->totloop;
           float best_dist_sq = FLT_MAX;
           int best_eidx_src = -1;
 
           for (; nloops--; ml_src++) {
-            MEdge *med_src = &edges_src[ml_src->e];
+            const MEdge *med_src = &edges_src[ml_src->e];
             float *co1_src = vcos_src[med_src->v1];
             float *co2_src = vcos_src[med_src->v2];
             float co_src[3];
@@ -1046,9 +1041,9 @@ void BKE_mesh_remap_calc_edges_from_mesh(const int mode,
 static void mesh_island_to_astar_graph_edge_process(MeshIslandStore *islands,
                                                     const int island_index,
                                                     BLI_AStarGraph *as_graph,
-                                                    MVert *verts,
-                                                    MPoly *polys,
-                                                    MLoop *loops,
+                                                    const MVert *verts,
+                                                    const MPoly *polys,
+                                                    const MLoop *loops,
                                                     const int edge_idx,
                                                     BLI_bitmap *done_edges,
                                                     MeshElemMap *edge_to_poly_map,
@@ -1063,7 +1058,7 @@ static void mesh_island_to_astar_graph_edge_process(MeshIslandStore *islands,
 
   for (i = 0; i < edge_to_poly_map[edge_idx].count; i++) {
     const int pidx = edge_to_poly_map[edge_idx].indices[i];
-    MPoly *mp = &polys[pidx];
+    const MPoly *mp = &polys[pidx];
     const int pidx_isld = islands ? poly_island_index_map[pidx] : pidx;
     void *custom_data = is_edge_innercut ? POINTER_FROM_INT(edge_idx) : POINTER_FROM_INT(-1);
 
@@ -1104,11 +1099,11 @@ static void mesh_island_to_astar_graph_edge_process(MeshIslandStore *islands,
 
 static void mesh_island_to_astar_graph(MeshIslandStore *islands,
                                        const int island_index,
-                                       MVert *verts,
+                                       const MVert *verts,
                                        MeshElemMap *edge_to_poly_map,
                                        const int numedges,
-                                       MLoop *loops,
-                                       MPoly *polys,
+                                       const MLoop *loops,
+                                       const MPoly *polys,
                                        const int numpolys,
                                        BLI_AStarGraph *r_as_graph)
 {
@@ -1158,7 +1153,7 @@ static void mesh_island_to_astar_graph(MeshIslandStore *islands,
 
   for (pidx_isld = node_num; pidx_isld--;) {
     const int pidx = islands ? island_poly_map->indices[pidx_isld] : pidx_isld;
-    MPoly *mp = &polys[pidx];
+    const MPoly *mp = &polys[pidx];
     int pl_idx, l_idx;
 
     if (poly_status[pidx_isld] == POLY_COMPLETE) {
@@ -1166,7 +1161,7 @@ static void mesh_island_to_astar_graph(MeshIslandStore *islands,
     }
 
     for (pl_idx = 0, l_idx = mp->loopstart; pl_idx < mp->totloop; pl_idx++, l_idx++) {
-      MLoop *ml = &loops[l_idx];
+      const MLoop *ml = &loops[l_idx];
 
       if (BLI_BITMAP_TEST(done_edges, ml->e)) {
         continue;
@@ -1234,13 +1229,13 @@ void BKE_mesh_remap_calc_loops_from_mesh(const int mode,
                                          const float max_dist,
                                          const float ray_radius,
                                          Mesh *mesh_dst,
-                                         MVert *verts_dst,
+                                         const MVert *verts_dst,
                                          const int numverts_dst,
-                                         MEdge *edges_dst,
+                                         const MEdge *edges_dst,
                                          const int numedges_dst,
-                                         MLoop *loops_dst,
+                                         const MLoop *loops_dst,
                                          const int numloops_dst,
-                                         MPoly *polys_dst,
+                                         const MPoly *polys_dst,
                                          const int numpolys_dst,
                                          CustomData *ldata_dst,
                                          const bool use_split_nors_dst,
@@ -1307,14 +1302,14 @@ void BKE_mesh_remap_calc_loops_from_mesh(const int mode,
     /* Unlike above, those are one-to-one mappings, simpler! */
     int *loop_to_poly_map_src = NULL;
 
-    MVert *verts_src = me_src->mvert;
+    const MVert *verts_src = BKE_mesh_verts(me_src);
     const int num_verts_src = me_src->totvert;
     float(*vcos_src)[3] = NULL;
-    MEdge *edges_src = me_src->medge;
+    const MEdge *edges_src = BKE_mesh_edges(me_src);
     const int num_edges_src = me_src->totedge;
-    MLoop *loops_src = me_src->mloop;
+    const MLoop *loops_src = BKE_mesh_loops(me_src);
     const int num_loops_src = me_src->totloop;
-    MPoly *polys_src = me_src->mpoly;
+    const MPoly *polys_src = BKE_mesh_polys(me_src);
     const int num_polys_src = me_src->totpoly;
     const MLoopTri *looptri_src = NULL;
     int num_looptri_src = 0;
@@ -1324,8 +1319,10 @@ void BKE_mesh_remap_calc_loops_from_mesh(const int mode,
     int *indices_interp = NULL;
     float *weights_interp = NULL;
 
-    MLoop *ml_src, *ml_dst;
-    MPoly *mp_src, *mp_dst;
+    const MLoop *ml_src;
+    const MLoop *ml_dst;
+    const MPoly *mp_src;
+    const MPoly *mp_dst;
     int tindex, pidx_dst, lidx_dst, plidx_dst, pidx_src, lidx_src, plidx_src;
 
     IslandResult **islands_res;
@@ -1357,7 +1354,7 @@ void BKE_mesh_remap_calc_loops_from_mesh(const int mode,
         const bool do_loop_nors_dst = (loop_nors_dst == NULL);
         if (!loop_nors_dst) {
           loop_nors_dst = CustomData_add_layer(
-              ldata_dst, CD_NORMAL, CD_CALLOC, NULL, numloops_dst);
+              ldata_dst, CD_NORMAL, CD_SET_DEFAULT, NULL, numloops_dst);
           CustomData_set_layer_flag(ldata_dst, CD_NORMAL, CD_FLAG_TEMPORARY);
         }
         if (dirty_nors_dst || do_loop_nors_dst) {
@@ -2153,10 +2150,10 @@ void BKE_mesh_remap_calc_polys_from_mesh(const int mode,
                                          const SpaceTransform *space_transform,
                                          const float max_dist,
                                          const float ray_radius,
-                                         Mesh *mesh_dst,
-                                         MVert *verts_dst,
-                                         MLoop *loops_dst,
-                                         MPoly *polys_dst,
+                                         const Mesh *mesh_dst,
+                                         const MVert *verts_dst,
+                                         const MLoop *loops_dst,
+                                         const MPoly *polys_dst,
                                          const int numpolys_dst,
                                          Mesh *me_src,
                                          MeshPairRemap *r_map)
@@ -2193,7 +2190,7 @@ void BKE_mesh_remap_calc_polys_from_mesh(const int mode,
       nearest.index = -1;
 
       for (i = 0; i < numpolys_dst; i++) {
-        MPoly *mp = &polys_dst[i];
+        const MPoly *mp = &polys_dst[i];
 
         BKE_mesh_calc_poly_center(mp, &loops_dst[mp->loopstart], verts_dst, tmp_co);
 
@@ -2218,7 +2215,7 @@ void BKE_mesh_remap_calc_polys_from_mesh(const int mode,
       BLI_assert(poly_nors_dst);
 
       for (i = 0; i < numpolys_dst; i++) {
-        MPoly *mp = &polys_dst[i];
+        const MPoly *mp = &polys_dst[i];
 
         BKE_mesh_calc_poly_center(mp, &loops_dst[mp->loopstart], verts_dst, tmp_co);
         copy_v3_v3(tmp_no, poly_nors_dst[i]);
@@ -2264,7 +2261,7 @@ void BKE_mesh_remap_calc_polys_from_mesh(const int mode,
         /* For each dst poly, we sample some rays from it (2D grid in pnor space)
          * and use their hits to interpolate from source polys. */
         /* NOTE: dst poly is early-converted into src space! */
-        MPoly *mp = &polys_dst[i];
+        const MPoly *mp = &polys_dst[i];
 
         int tot_rays, done_rays = 0;
         float poly_area_2d_inv, done_area = 0.0f;
@@ -2307,7 +2304,7 @@ void BKE_mesh_remap_calc_polys_from_mesh(const int mode,
         INIT_MINMAX2(poly_dst_2d_min, poly_dst_2d_max);
 
         for (j = 0; j < mp->totloop; j++) {
-          MLoop *ml = &loops_dst[j + mp->loopstart];
+          const MLoop *ml = &loops_dst[j + mp->loopstart];
           copy_v3_v3(tmp_co, verts_dst[ml->v].co);
           if (space_transform) {
             BLI_space_transform_apply(space_transform, tmp_co);
diff --git a/source/blender/blenkernel/intern/mesh_remesh_voxel.cc b/source/blender/blenkernel/intern/mesh_remesh_voxel.cc
index 85aed01ce52..a77879fb573 100644
--- a/source/blender/blenkernel/intern/mesh_remesh_voxel.cc
+++ b/source/blender/blenkernel/intern/mesh_remesh_voxel.cc
@@ -61,14 +61,15 @@ static Mesh *remesh_quadriflow(const Mesh *input_mesh,
                                void (*update_cb)(void *, float progress, int *cancel),
                                void *update_cb_data)
 {
-  /* Ensure that the triangulated mesh data is up to data */
+  const Span input_verts = input_mesh->verts();
+  const Span input_loops = input_mesh->loops();
   const MLoopTri *looptri = BKE_mesh_runtime_looptri_ensure(input_mesh);
 
   /* Gather the required data for export to the internal quadriflow mesh format. */
   MVertTri *verttri = (MVertTri *)MEM_callocN(
       sizeof(*verttri) * BKE_mesh_runtime_looptri_len(input_mesh), "remesh_looptri");
   BKE_mesh_runtime_verttri_from_looptri(
-      verttri, input_mesh->mloop, looptri, BKE_mesh_runtime_looptri_len(input_mesh));
+      verttri, input_loops.data(), looptri, BKE_mesh_runtime_looptri_len(input_mesh));
 
   const int totfaces = BKE_mesh_runtime_looptri_len(input_mesh);
   const int totverts = input_mesh->totvert;
@@ -76,7 +77,7 @@ static Mesh *remesh_quadriflow(const Mesh *input_mesh,
   Array faces(totfaces * 3);
 
   for (const int i : IndexRange(totverts)) {
-    verts[i] = input_mesh->mvert[i].co;
+    verts[i] = input_verts[i].co;
   }
 
   for (const int i : IndexRange(totfaces)) {
@@ -123,20 +124,24 @@ static Mesh *remesh_quadriflow(const Mesh *input_mesh,
 
   /* Construct the new output mesh */
   Mesh *mesh = BKE_mesh_new_nomain(qrd.out_totverts, 0, 0, qrd.out_totfaces * 4, qrd.out_totfaces);
+  BKE_mesh_copy_parameters(mesh, input_mesh);
+  MutableSpan mesh_verts = mesh->verts_for_write();
+  MutableSpan polys = mesh->polys_for_write();
+  MutableSpan loops = mesh->loops_for_write();
 
   for (const int i : IndexRange(qrd.out_totverts)) {
-    copy_v3_v3(mesh->mvert[i].co, &qrd.out_verts[i * 3]);
+    copy_v3_v3(mesh_verts[i].co, &qrd.out_verts[i * 3]);
   }
 
   for (const int i : IndexRange(qrd.out_totfaces)) {
-    MPoly &poly = mesh->mpoly[i];
+    MPoly &poly = polys[i];
     const int loopstart = i * 4;
     poly.loopstart = loopstart;
     poly.totloop = 4;
-    mesh->mloop[loopstart].v = qrd.out_faces[loopstart];
-    mesh->mloop[loopstart + 1].v = qrd.out_faces[loopstart + 1];
-    mesh->mloop[loopstart + 2].v = qrd.out_faces[loopstart + 2];
-    mesh->mloop[loopstart + 3].v = qrd.out_faces[loopstart + 3];
+    loops[loopstart].v = qrd.out_faces[loopstart];
+    loops[loopstart + 1].v = qrd.out_faces[loopstart + 1];
+    loops[loopstart + 2].v = qrd.out_faces[loopstart + 2];
+    loops[loopstart + 3].v = qrd.out_faces[loopstart + 3];
   }
 
   BKE_mesh_calc_edges(mesh, false, false);
@@ -186,7 +191,8 @@ Mesh *BKE_mesh_remesh_quadriflow(const Mesh *mesh,
 static openvdb::FloatGrid::Ptr remesh_voxel_level_set_create(const Mesh *mesh,
                                                              const float voxel_size)
 {
-  Span mloop{mesh->mloop, mesh->totloop};
+  const Span verts = mesh->verts();
+  const Span loops = mesh->loops();
   Span looptris{BKE_mesh_runtime_looptri_ensure(mesh),
                           BKE_mesh_runtime_looptri_len(mesh)};
 
@@ -194,14 +200,14 @@ static openvdb::FloatGrid::Ptr remesh_voxel_level_set_create(const Mesh *mesh,
   std::vector triangles(looptris.size());
 
   for (const int i : IndexRange(mesh->totvert)) {
-    const float3 co = mesh->mvert[i].co;
+    const float3 co = verts[i].co;
     points[i] = openvdb::Vec3s(co.x, co.y, co.z);
   }
 
   for (const int i : IndexRange(looptris.size())) {
     const MLoopTri &loop_tri = looptris[i];
     triangles[i] = openvdb::Vec3I(
-        mloop[loop_tri.tri[0]].v, mloop[loop_tri.tri[1]].v, mloop[loop_tri.tri[2]].v);
+        loops[loop_tri.tri[0]].v, loops[loop_tri.tri[1]].v, loops[loop_tri.tri[2]].v);
   }
 
   openvdb::math::Transform::Ptr transform = openvdb::math::Transform::createLinearTransform(
@@ -225,34 +231,34 @@ static Mesh *remesh_voxel_volume_to_mesh(const openvdb::FloatGrid::Ptr level_set
 
   Mesh *mesh = BKE_mesh_new_nomain(
       vertices.size(), 0, 0, quads.size() * 4 + tris.size() * 3, quads.size() + tris.size());
-  MutableSpan mverts{mesh->mvert, mesh->totvert};
-  MutableSpan mloops{mesh->mloop, mesh->totloop};
-  MutableSpan mpolys{mesh->mpoly, mesh->totpoly};
+  MutableSpan mesh_verts = mesh->verts_for_write();
+  MutableSpan mesh_polys = mesh->polys_for_write();
+  MutableSpan mesh_loops = mesh->loops_for_write();
 
-  for (const int i : mverts.index_range()) {
-    copy_v3_v3(mverts[i].co, float3(vertices[i].x(), vertices[i].y(), vertices[i].z()));
+  for (const int i : mesh_verts.index_range()) {
+    copy_v3_v3(mesh_verts[i].co, float3(vertices[i].x(), vertices[i].y(), vertices[i].z()));
   }
 
   for (const int i : IndexRange(quads.size())) {
-    MPoly &poly = mpolys[i];
+    MPoly &poly = mesh_polys[i];
     const int loopstart = i * 4;
     poly.loopstart = loopstart;
     poly.totloop = 4;
-    mloops[loopstart].v = quads[i][0];
-    mloops[loopstart + 1].v = quads[i][3];
-    mloops[loopstart + 2].v = quads[i][2];
-    mloops[loopstart + 3].v = quads[i][1];
+    mesh_loops[loopstart].v = quads[i][0];
+    mesh_loops[loopstart + 1].v = quads[i][3];
+    mesh_loops[loopstart + 2].v = quads[i][2];
+    mesh_loops[loopstart + 3].v = quads[i][1];
   }
 
   const int triangle_loop_start = quads.size() * 4;
   for (const int i : IndexRange(tris.size())) {
-    MPoly &poly = mpolys[quads.size() + i];
+    MPoly &poly = mesh_polys[quads.size() + i];
     const int loopstart = triangle_loop_start + i * 3;
     poly.loopstart = loopstart;
     poly.totloop = 3;
-    mloops[loopstart].v = tris[i][2];
-    mloops[loopstart + 1].v = tris[i][1];
-    mloops[loopstart + 2].v = tris[i][0];
+    mesh_loops[loopstart].v = tris[i][2];
+    mesh_loops[loopstart + 1].v = tris[i][1];
+    mesh_loops[loopstart + 2].v = tris[i][0];
   }
 
   BKE_mesh_calc_edges(mesh, false, false);
@@ -268,18 +274,24 @@ Mesh *BKE_mesh_remesh_voxel(const Mesh *mesh,
 {
 #ifdef WITH_OPENVDB
   openvdb::FloatGrid::Ptr level_set = remesh_voxel_level_set_create(mesh, voxel_size);
-  return remesh_voxel_volume_to_mesh(level_set, isovalue, adaptivity, false);
+  Mesh *result = remesh_voxel_volume_to_mesh(level_set, isovalue, adaptivity, false);
+  BKE_mesh_copy_parameters(result, mesh);
+  return result;
 #else
   UNUSED_VARS(mesh, voxel_size, adaptivity, isovalue);
   return nullptr;
 #endif
 }
 
-void BKE_mesh_remesh_reproject_paint_mask(Mesh *target, Mesh *source)
+void BKE_mesh_remesh_reproject_paint_mask(Mesh *target, const Mesh *source)
 {
   BVHTreeFromMesh bvhtree = {nullptr};
   BKE_bvhtree_from_mesh_get(&bvhtree, source, BVHTREE_FROM_VERTS, 2);
-  MVert *target_verts = (MVert *)CustomData_get_layer(&target->vdata, CD_MVERT);
+  const MVert *target_verts = (const MVert *)CustomData_get_layer(&target->vdata, CD_MVERT);
+  const float *source_mask = (const float *)CustomData_get_layer(&source->vdata, CD_PAINT_MASK);
+  if (source_mask == nullptr) {
+    return;
+  }
 
   float *target_mask;
   if (CustomData_has_layer(&target->vdata, CD_PAINT_MASK)) {
@@ -287,16 +299,7 @@ void BKE_mesh_remesh_reproject_paint_mask(Mesh *target, Mesh *source)
   }
   else {
     target_mask = (float *)CustomData_add_layer(
-        &target->vdata, CD_PAINT_MASK, CD_CALLOC, nullptr, target->totvert);
-  }
-
-  const float *source_mask;
-  if (CustomData_has_layer(&source->vdata, CD_PAINT_MASK)) {
-    source_mask = (float *)CustomData_get_layer(&source->vdata, CD_PAINT_MASK);
-  }
-  else {
-    source_mask = (float *)CustomData_add_layer(
-        &source->vdata, CD_PAINT_MASK, CD_CALLOC, nullptr, source->totvert);
+        &target->vdata, CD_PAINT_MASK, CD_CONSTRUCT, nullptr, target->totvert);
   }
 
   for (int i = 0; i < target->totvert; i++) {
@@ -313,13 +316,16 @@ void BKE_mesh_remesh_reproject_paint_mask(Mesh *target, Mesh *source)
   free_bvhtree_from_mesh(&bvhtree);
 }
 
-void BKE_remesh_reproject_sculpt_face_sets(Mesh *target, Mesh *source)
+void BKE_remesh_reproject_sculpt_face_sets(Mesh *target, const Mesh *source)
 {
-  BVHTreeFromMesh bvhtree = {nullptr};
-
   const MPoly *target_polys = (const MPoly *)CustomData_get_layer(&target->pdata, CD_MPOLY);
   const MVert *target_verts = (const MVert *)CustomData_get_layer(&target->vdata, CD_MVERT);
   const MLoop *target_loops = (const MLoop *)CustomData_get_layer(&target->ldata, CD_MLOOP);
+  const int *source_face_sets = (const int *)CustomData_get_layer(&source->pdata,
+                                                                  CD_SCULPT_FACE_SETS);
+  if (source_face_sets == nullptr) {
+    return;
+  }
 
   int *target_face_sets;
   if (CustomData_has_layer(&target->pdata, CD_SCULPT_FACE_SETS)) {
@@ -327,19 +333,11 @@ void BKE_remesh_reproject_sculpt_face_sets(Mesh *target, Mesh *source)
   }
   else {
     target_face_sets = (int *)CustomData_add_layer(
-        &target->pdata, CD_SCULPT_FACE_SETS, CD_CALLOC, nullptr, target->totpoly);
-  }
-
-  const int *source_face_sets;
-  if (CustomData_has_layer(&source->pdata, CD_SCULPT_FACE_SETS)) {
-    source_face_sets = (const int *)CustomData_get_layer(&source->pdata, CD_SCULPT_FACE_SETS);
-  }
-  else {
-    source_face_sets = (const int *)CustomData_add_layer(
-        &source->pdata, CD_SCULPT_FACE_SETS, CD_CALLOC, nullptr, source->totpoly);
+        &target->pdata, CD_SCULPT_FACE_SETS, CD_CONSTRUCT, nullptr, target->totpoly);
   }
 
   const MLoopTri *looptri = BKE_mesh_runtime_looptri_ensure(source);
+  BVHTreeFromMesh bvhtree = {nullptr};
   BKE_bvhtree_from_mesh_get(&bvhtree, source, BVHTREE_FROM_LOOPTRI, 2);
 
   for (int i = 0; i < target->totpoly; i++) {
@@ -386,7 +384,7 @@ void BKE_remesh_reproject_vertex_paint(Mesh *target, const Mesh *source)
       int elem_num = domain == ATTR_DOMAIN_POINT ? target->totvert : target->totloop;
 
       CustomData_add_layer_named(
-          target_cdata, layer->type, CD_CALLOC, nullptr, elem_num, layer->name);
+          target_cdata, layer->type, CD_SET_DEFAULT, nullptr, elem_num, layer->name);
       layer_i = CustomData_get_named_layer_index(target_cdata, layer->type, layer->name);
     }
 
diff --git a/source/blender/blenkernel/intern/mesh_runtime.cc b/source/blender/blenkernel/intern/mesh_runtime.cc
index 4521c519f45..4b6433edd5a 100644
--- a/source/blender/blenkernel/intern/mesh_runtime.cc
+++ b/source/blender/blenkernel/intern/mesh_runtime.cc
@@ -23,6 +23,9 @@
 #include "BKE_shrinkwrap.h"
 #include "BKE_subdiv_ccg.h"
 
+using blender::MutableSpan;
+using blender::Span;
+
 /* -------------------------------------------------------------------- */
 /** \name Mesh Runtime Struct Utils
  * \{ */
@@ -147,10 +150,13 @@ void BKE_mesh_runtime_looptri_recalc(Mesh *mesh)
 {
   mesh_ensure_looptri_data(mesh);
   BLI_assert(mesh->totpoly == 0 || mesh->runtime.looptris.array_wip != nullptr);
+  const Span verts = mesh->verts();
+  const Span polys = mesh->polys();
+  const Span loops = mesh->loops();
 
-  BKE_mesh_recalc_looptri(mesh->mloop,
-                          mesh->mpoly,
-                          mesh->mvert,
+  BKE_mesh_recalc_looptri(loops.data(),
+                          polys.data(),
+                          verts.data(),
                           mesh->totloop,
                           mesh->totpoly,
                           mesh->runtime.looptris.array_wip);
@@ -272,12 +278,12 @@ void BKE_mesh_tag_coords_changed_uniformly(Mesh *mesh)
   const bool poly_normals_were_dirty = BKE_mesh_poly_normals_are_dirty(mesh);
 
   BKE_mesh_tag_coords_changed(mesh);
-  /* The normals didn't change, since all vertices moved by the same amount. */
+  /* The normals didn't change, since all verts moved by the same amount. */
   if (!vert_normals_were_dirty) {
-    BKE_mesh_poly_normals_clear_dirty(mesh);
+    BKE_mesh_vertex_normals_clear_dirty(mesh);
   }
   if (!poly_normals_were_dirty) {
-    BKE_mesh_vertex_normals_clear_dirty(mesh);
+    BKE_mesh_poly_normals_clear_dirty(mesh);
   }
 }
 
@@ -324,6 +330,11 @@ bool BKE_mesh_runtime_is_valid(Mesh *me_eval)
     printf("MESH: %s\n", me_eval->id.name + 2);
   }
 
+  MutableSpan verts = me_eval->verts_for_write();
+  MutableSpan edges = me_eval->edges_for_write();
+  MutableSpan polys = me_eval->polys_for_write();
+  MutableSpan loops = me_eval->loops_for_write();
+
   is_valid &= BKE_mesh_validate_all_customdata(
       &me_eval->vdata,
       me_eval->totvert,
@@ -338,21 +349,22 @@ bool BKE_mesh_runtime_is_valid(Mesh *me_eval)
       do_fixes,
       &changed);
 
-  is_valid &= BKE_mesh_validate_arrays(me_eval,
-                                       me_eval->mvert,
-                                       me_eval->totvert,
-                                       me_eval->medge,
-                                       me_eval->totedge,
-                                       me_eval->mface,
-                                       me_eval->totface,
-                                       me_eval->mloop,
-                                       me_eval->totloop,
-                                       me_eval->mpoly,
-                                       me_eval->totpoly,
-                                       me_eval->dvert,
-                                       do_verbose,
-                                       do_fixes,
-                                       &changed);
+  is_valid &= BKE_mesh_validate_arrays(
+      me_eval,
+      verts.data(),
+      verts.size(),
+      edges.data(),
+      edges.size(),
+      static_cast(CustomData_get_layer(&me_eval->fdata, CD_MFACE)),
+      me_eval->totface,
+      loops.data(),
+      loops.size(),
+      polys.data(),
+      polys.size(),
+      me_eval->deform_verts_for_write().data(),
+      do_verbose,
+      do_fixes,
+      &changed);
 
   BLI_assert(changed == false);
 
diff --git a/source/blender/blenkernel/intern/mesh_sample.cc b/source/blender/blenkernel/intern/mesh_sample.cc
index dd09a3d6917..1ddac19304d 100644
--- a/source/blender/blenkernel/intern/mesh_sample.cc
+++ b/source/blender/blenkernel/intern/mesh_sample.cc
@@ -2,6 +2,7 @@
 
 #include "BKE_attribute_math.hh"
 #include "BKE_bvhutils.h"
+#include "BKE_mesh.h"
 #include "BKE_mesh_runtime.h"
 #include "BKE_mesh_sample.hh"
 
@@ -16,10 +17,11 @@ template
 BLI_NOINLINE static void sample_point_attribute(const Mesh &mesh,
                                                 const Span looptri_indices,
                                                 const Span bary_coords,
-                                                const VArray &data_in,
+                                                const VArray &src,
                                                 const IndexMask mask,
-                                                const MutableSpan data_out)
+                                                const MutableSpan dst)
 {
+  const Span loops = mesh.loops();
   const Span looptris{BKE_mesh_runtime_looptri_ensure(&mesh),
                                 BKE_mesh_runtime_looptri_len(&mesh)};
 
@@ -28,34 +30,34 @@ BLI_NOINLINE static void sample_point_attribute(const Mesh &mesh,
     const MLoopTri &looptri = looptris[looptri_index];
     const float3 &bary_coord = bary_coords[i];
 
-    const int v0_index = mesh.mloop[looptri.tri[0]].v;
-    const int v1_index = mesh.mloop[looptri.tri[1]].v;
-    const int v2_index = mesh.mloop[looptri.tri[2]].v;
+    const int v0_index = loops[looptri.tri[0]].v;
+    const int v1_index = loops[looptri.tri[1]].v;
+    const int v2_index = loops[looptri.tri[2]].v;
 
-    const T v0 = data_in[v0_index];
-    const T v1 = data_in[v1_index];
-    const T v2 = data_in[v2_index];
+    const T v0 = src[v0_index];
+    const T v1 = src[v1_index];
+    const T v2 = src[v2_index];
 
     const T interpolated_value = attribute_math::mix3(bary_coord, v0, v1, v2);
-    data_out[i] = interpolated_value;
+    dst[i] = interpolated_value;
   }
 }
 
 void sample_point_attribute(const Mesh &mesh,
                             const Span looptri_indices,
                             const Span bary_coords,
-                            const GVArray &data_in,
+                            const GVArray &src,
                             const IndexMask mask,
-                            const GMutableSpan data_out)
+                            const GMutableSpan dst)
 {
-  BLI_assert(data_in.size() == mesh.totvert);
-  BLI_assert(data_in.type() == data_out.type());
+  BLI_assert(src.size() == mesh.totvert);
+  BLI_assert(src.type() == dst.type());
 
-  const CPPType &type = data_in.type();
+  const CPPType &type = src.type();
   attribute_math::convert_to_static_type(type, [&](auto dummy) {
     using T = decltype(dummy);
     sample_point_attribute(
-        mesh, looptri_indices, bary_coords, data_in.typed(), mask, data_out.typed());
+        mesh, looptri_indices, bary_coords, src.typed(), mask, dst.typed());
   });
 }
 
@@ -63,9 +65,9 @@ template
 BLI_NOINLINE static void sample_corner_attribute(const Mesh &mesh,
                                                  const Span looptri_indices,
                                                  const Span bary_coords,
-                                                 const VArray &data_in,
+                                                 const VArray &src,
                                                  const IndexMask mask,
-                                                 const MutableSpan data_out)
+                                                 const MutableSpan dst)
 {
   const Span looptris{BKE_mesh_runtime_looptri_ensure(&mesh),
                                 BKE_mesh_runtime_looptri_len(&mesh)};
@@ -79,39 +81,39 @@ BLI_NOINLINE static void sample_corner_attribute(const Mesh &mesh,
     const int loop_index_1 = looptri.tri[1];
     const int loop_index_2 = looptri.tri[2];
 
-    const T v0 = data_in[loop_index_0];
-    const T v1 = data_in[loop_index_1];
-    const T v2 = data_in[loop_index_2];
+    const T v0 = src[loop_index_0];
+    const T v1 = src[loop_index_1];
+    const T v2 = src[loop_index_2];
 
     const T interpolated_value = attribute_math::mix3(bary_coord, v0, v1, v2);
-    data_out[i] = interpolated_value;
+    dst[i] = interpolated_value;
   }
 }
 
 void sample_corner_attribute(const Mesh &mesh,
                              const Span looptri_indices,
                              const Span bary_coords,
-                             const GVArray &data_in,
+                             const GVArray &src,
                              const IndexMask mask,
-                             const GMutableSpan data_out)
+                             const GMutableSpan dst)
 {
-  BLI_assert(data_in.size() == mesh.totloop);
-  BLI_assert(data_in.type() == data_out.type());
+  BLI_assert(src.size() == mesh.totloop);
+  BLI_assert(src.type() == dst.type());
 
-  const CPPType &type = data_in.type();
+  const CPPType &type = src.type();
   attribute_math::convert_to_static_type(type, [&](auto dummy) {
     using T = decltype(dummy);
     sample_corner_attribute(
-        mesh, looptri_indices, bary_coords, data_in.typed(), mask, data_out.typed());
+        mesh, looptri_indices, bary_coords, src.typed(), mask, dst.typed());
   });
 }
 
 template
 void sample_face_attribute(const Mesh &mesh,
                            const Span looptri_indices,
-                           const VArray &data_in,
+                           const VArray &src,
                            const IndexMask mask,
-                           const MutableSpan data_out)
+                           const MutableSpan dst)
 {
   const Span looptris{BKE_mesh_runtime_looptri_ensure(&mesh),
                                 BKE_mesh_runtime_looptri_len(&mesh)};
@@ -120,23 +122,23 @@ void sample_face_attribute(const Mesh &mesh,
     const int looptri_index = looptri_indices[i];
     const MLoopTri &looptri = looptris[looptri_index];
     const int poly_index = looptri.poly;
-    data_out[i] = data_in[poly_index];
+    dst[i] = src[poly_index];
   }
 }
 
 void sample_face_attribute(const Mesh &mesh,
                            const Span looptri_indices,
-                           const GVArray &data_in,
+                           const GVArray &src,
                            const IndexMask mask,
-                           const GMutableSpan data_out)
+                           const GMutableSpan dst)
 {
-  BLI_assert(data_in.size() == mesh.totpoly);
-  BLI_assert(data_in.type() == data_out.type());
+  BLI_assert(src.size() == mesh.totpoly);
+  BLI_assert(src.type() == dst.type());
 
-  const CPPType &type = data_in.type();
+  const CPPType &type = src.type();
   attribute_math::convert_to_static_type(type, [&](auto dummy) {
     using T = decltype(dummy);
-    sample_face_attribute(mesh, looptri_indices, data_in.typed(), mask, data_out.typed());
+    sample_face_attribute(mesh, looptri_indices, src.typed(), mask, dst.typed());
   });
 }
 
@@ -157,6 +159,8 @@ Span MeshAttributeInterpolator::ensure_barycentric_coords()
   }
   bary_coords_.reinitialize(mask_.min_array_size());
 
+  const Span verts = mesh_->verts();
+  const Span loops = mesh_->loops();
   const Span looptris{BKE_mesh_runtime_looptri_ensure(mesh_),
                                 BKE_mesh_runtime_looptri_len(mesh_)};
 
@@ -164,14 +168,14 @@ Span MeshAttributeInterpolator::ensure_barycentric_coords()
     const int looptri_index = looptri_indices_[i];
     const MLoopTri &looptri = looptris[looptri_index];
 
-    const int v0_index = mesh_->mloop[looptri.tri[0]].v;
-    const int v1_index = mesh_->mloop[looptri.tri[1]].v;
-    const int v2_index = mesh_->mloop[looptri.tri[2]].v;
+    const int v0_index = loops[looptri.tri[0]].v;
+    const int v1_index = loops[looptri.tri[1]].v;
+    const int v2_index = loops[looptri.tri[2]].v;
 
     interp_weights_tri_v3(bary_coords_[i],
-                          mesh_->mvert[v0_index].co,
-                          mesh_->mvert[v1_index].co,
-                          mesh_->mvert[v2_index].co,
+                          verts[v0_index].co,
+                          verts[v1_index].co,
+                          verts[v2_index].co,
                           positions_[i]);
   }
   return bary_coords_;
@@ -185,6 +189,8 @@ Span MeshAttributeInterpolator::ensure_nearest_weights()
   }
   nearest_weights_.reinitialize(mask_.min_array_size());
 
+  const Span verts = mesh_->verts();
+  const Span loops = mesh_->loops();
   const Span looptris{BKE_mesh_runtime_looptri_ensure(mesh_),
                                 BKE_mesh_runtime_looptri_len(mesh_)};
 
@@ -192,13 +198,13 @@ Span MeshAttributeInterpolator::ensure_nearest_weights()
     const int looptri_index = looptri_indices_[i];
     const MLoopTri &looptri = looptris[looptri_index];
 
-    const int v0_index = mesh_->mloop[looptri.tri[0]].v;
-    const int v1_index = mesh_->mloop[looptri.tri[1]].v;
-    const int v2_index = mesh_->mloop[looptri.tri[2]].v;
+    const int v0_index = loops[looptri.tri[0]].v;
+    const int v1_index = loops[looptri.tri[1]].v;
+    const int v2_index = loops[looptri.tri[2]].v;
 
-    const float d0 = len_squared_v3v3(positions_[i], mesh_->mvert[v0_index].co);
-    const float d1 = len_squared_v3v3(positions_[i], mesh_->mvert[v1_index].co);
-    const float d2 = len_squared_v3v3(positions_[i], mesh_->mvert[v2_index].co);
+    const float d0 = len_squared_v3v3(positions_[i], verts[v0_index].co);
+    const float d1 = len_squared_v3v3(positions_[i], verts[v1_index].co);
+    const float d2 = len_squared_v3v3(positions_[i], verts[v2_index].co);
 
     nearest_weights_[i] = MIN3_PAIR(d0, d1, d2, float3(1, 0, 0), float3(0, 1, 0), float3(0, 0, 1));
   }
@@ -219,45 +225,31 @@ void MeshAttributeInterpolator::sample_data(const GVArray &src,
   if (ELEM(domain, ATTR_DOMAIN_POINT, ATTR_DOMAIN_CORNER)) {
     switch (mode) {
       case eAttributeMapMode::INTERPOLATED:
-        weights = ensure_barycentric_coords();
+        weights = this->ensure_barycentric_coords();
         break;
       case eAttributeMapMode::NEAREST:
-        weights = ensure_nearest_weights();
+        weights = this->ensure_nearest_weights();
         break;
     }
   }
 
   /* Interpolate the source attributes on the surface. */
   switch (domain) {
-    case ATTR_DOMAIN_POINT: {
+    case ATTR_DOMAIN_POINT:
       sample_point_attribute(*mesh_, looptri_indices_, weights, src, mask_, dst);
       break;
-    }
-    case ATTR_DOMAIN_FACE: {
+    case ATTR_DOMAIN_FACE:
       sample_face_attribute(*mesh_, looptri_indices_, src, mask_, dst);
       break;
-    }
-    case ATTR_DOMAIN_CORNER: {
+    case ATTR_DOMAIN_CORNER:
       sample_corner_attribute(*mesh_, looptri_indices_, weights, src, mask_, dst);
       break;
-    }
-    case ATTR_DOMAIN_EDGE: {
+    case ATTR_DOMAIN_EDGE:
       /* Not yet supported. */
       break;
-    }
-    default: {
+    default:
       BLI_assert_unreachable();
       break;
-    }
-  }
-}
-
-void MeshAttributeInterpolator::sample_attribute(const GAttributeReader &src_attribute,
-                                                 GSpanAttributeWriter &dst_attribute,
-                                                 eAttributeMapMode mode)
-{
-  if (src_attribute && dst_attribute) {
-    this->sample_data(src_attribute.varray, src_attribute.domain, mode, dst_attribute.span);
   }
 }
 
@@ -271,6 +263,8 @@ int sample_surface_points_spherical(RandomNumberGenerator &rng,
                                     Vector &r_looptri_indices,
                                     Vector &r_positions)
 {
+  const Span verts = mesh.verts();
+  const Span loops = mesh.loops();
   const Span looptris{BKE_mesh_runtime_looptri_ensure(&mesh),
                                 BKE_mesh_runtime_looptri_len(&mesh)};
 
@@ -284,9 +278,9 @@ int sample_surface_points_spherical(RandomNumberGenerator &rng,
   for (const int looptri_index : looptri_indices_to_sample) {
     const MLoopTri &looptri = looptris[looptri_index];
 
-    const float3 &v0 = mesh.mvert[mesh.mloop[looptri.tri[0]].v].co;
-    const float3 &v1 = mesh.mvert[mesh.mloop[looptri.tri[1]].v].co;
-    const float3 &v2 = mesh.mvert[mesh.mloop[looptri.tri[2]].v].co;
+    const float3 &v0 = verts[loops[looptri.tri[0]].v].co;
+    const float3 &v1 = verts[loops[looptri.tri[1]].v].co;
+    const float3 &v2 = verts[loops[looptri.tri[2]].v].co;
 
     const float looptri_area = area_tri_v3(v0, v1, v2);
 
@@ -367,6 +361,8 @@ int sample_surface_points_projected(
     Vector &r_looptri_indices,
     Vector &r_positions)
 {
+  const Span verts = mesh.verts();
+  const Span loops = mesh.loops();
   const Span looptris{BKE_mesh_runtime_looptri_ensure(&mesh),
                                 BKE_mesh_runtime_looptri_len(&mesh)};
 
@@ -408,7 +404,8 @@ int sample_surface_points_projected(
     const int looptri_index = ray_hit.index;
     const float3 pos = ray_hit.co;
 
-    const float3 bary_coords = compute_bary_coord_in_triangle(mesh, looptris[looptri_index], pos);
+    const float3 bary_coords = compute_bary_coord_in_triangle(
+        verts, loops, looptris[looptri_index], pos);
 
     r_positions.append(pos);
     r_bary_coords.append(bary_coords);
@@ -418,13 +415,14 @@ int sample_surface_points_projected(
   return point_count;
 }
 
-float3 compute_bary_coord_in_triangle(const Mesh &mesh,
+float3 compute_bary_coord_in_triangle(const Span verts,
+                                      const Span loops,
                                       const MLoopTri &looptri,
                                       const float3 &position)
 {
-  const float3 &v0 = mesh.mvert[mesh.mloop[looptri.tri[0]].v].co;
-  const float3 &v1 = mesh.mvert[mesh.mloop[looptri.tri[1]].v].co;
-  const float3 &v2 = mesh.mvert[mesh.mloop[looptri.tri[2]].v].co;
+  const float3 &v0 = verts[loops[looptri.tri[0]].v].co;
+  const float3 &v1 = verts[loops[looptri.tri[1]].v].co;
+  const float3 &v2 = verts[loops[looptri.tri[2]].v].co;
   float3 bary_coords;
   interp_weights_tri_v3(bary_coords, v0, v1, v2, position);
   return bary_coords;
diff --git a/source/blender/blenkernel/intern/mesh_tangent.c b/source/blender/blenkernel/intern/mesh_tangent.c
deleted file mode 100644
index a677a0d6ebb..00000000000
--- a/source/blender/blenkernel/intern/mesh_tangent.c
+++ /dev/null
@@ -1,741 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later
- * Copyright 2001-2002 NaN Holding BV. All rights reserved. */
-
-/** \file
- * \ingroup bke
- *
- * Functions to evaluate mesh tangents.
- */
-
-#include 
-
-#include "MEM_guardedalloc.h"
-
-#include "DNA_mesh_types.h"
-#include "DNA_meshdata_types.h"
-
-#include "BLI_math.h"
-#include "BLI_task.h"
-#include "BLI_utildefines.h"
-
-#include "BKE_customdata.h"
-#include "BKE_mesh.h"
-#include "BKE_mesh_runtime.h"
-#include "BKE_mesh_tangent.h"
-#include "BKE_report.h"
-
-#include "BLI_strict_flags.h"
-
-#include "atomic_ops.h"
-#include "mikktspace.h"
-
-/* -------------------------------------------------------------------- */
-/** \name Mesh Tangent Calculations (Single Layer)
- * \{ */
-
-/* Tangent space utils. */
-
-/* User data. */
-typedef struct {
-  const MPoly *mpolys;     /* faces */
-  const MLoop *mloops;     /* faces's vertices */
-  const MVert *mverts;     /* vertices */
-  const MLoopUV *luvs;     /* texture coordinates */
-  const float (*lnors)[3]; /* loops' normals */
-  float (*tangents)[4];    /* output tangents */
-  int num_polys;           /* number of polygons */
-} BKEMeshToTangent;
-
-/* Mikktspace's API */
-static int get_num_faces(const SMikkTSpaceContext *pContext)
-{
-  BKEMeshToTangent *p_mesh = (BKEMeshToTangent *)pContext->m_pUserData;
-  return p_mesh->num_polys;
-}
-
-static int get_num_verts_of_face(const SMikkTSpaceContext *pContext, const int face_idx)
-{
-  BKEMeshToTangent *p_mesh = (BKEMeshToTangent *)pContext->m_pUserData;
-  return p_mesh->mpolys[face_idx].totloop;
-}
-
-static void get_position(const SMikkTSpaceContext *pContext,
-                         float r_co[3],
-                         const int face_idx,
-                         const int vert_idx)
-{
-  BKEMeshToTangent *p_mesh = (BKEMeshToTangent *)pContext->m_pUserData;
-  const int loop_idx = p_mesh->mpolys[face_idx].loopstart + vert_idx;
-  copy_v3_v3(r_co, p_mesh->mverts[p_mesh->mloops[loop_idx].v].co);
-}
-
-static void get_texture_coordinate(const SMikkTSpaceContext *pContext,
-                                   float r_uv[2],
-                                   const int face_idx,
-                                   const int vert_idx)
-{
-  BKEMeshToTangent *p_mesh = (BKEMeshToTangent *)pContext->m_pUserData;
-  copy_v2_v2(r_uv, p_mesh->luvs[p_mesh->mpolys[face_idx].loopstart + vert_idx].uv);
-}
-
-static void get_normal(const SMikkTSpaceContext *pContext,
-                       float r_no[3],
-                       const int face_idx,
-                       const int vert_idx)
-{
-  BKEMeshToTangent *p_mesh = (BKEMeshToTangent *)pContext->m_pUserData;
-  copy_v3_v3(r_no, p_mesh->lnors[p_mesh->mpolys[face_idx].loopstart + vert_idx]);
-}
-
-static void set_tspace(const SMikkTSpaceContext *pContext,
-                       const float fv_tangent[3],
-                       const float face_sign,
-                       const int face_idx,
-                       const int vert_idx)
-{
-  BKEMeshToTangent *p_mesh = (BKEMeshToTangent *)pContext->m_pUserData;
-  float *p_res = p_mesh->tangents[p_mesh->mpolys[face_idx].loopstart + vert_idx];
-  copy_v3_v3(p_res, fv_tangent);
-  p_res[3] = face_sign;
-}
-
-void BKE_mesh_calc_loop_tangent_single_ex(const MVert *mverts,
-                                          const int UNUSED(numVerts),
-                                          const MLoop *mloops,
-                                          float (*r_looptangent)[4],
-                                          const float (*loopnors)[3],
-                                          const MLoopUV *loopuvs,
-                                          const int UNUSED(numLoops),
-                                          const MPoly *mpolys,
-                                          const int numPolys,
-                                          ReportList *reports)
-{
-  BKEMeshToTangent mesh_to_tangent = {NULL};
-  SMikkTSpaceContext s_context = {NULL};
-  SMikkTSpaceInterface s_interface = {NULL};
-
-  const MPoly *mp;
-  int mp_index;
-
-  /* First check we do have a tris/quads only mesh. */
-  for (mp = mpolys, mp_index = 0; mp_index < numPolys; mp++, mp_index++) {
-    if (mp->totloop > 4) {
-      BKE_report(
-          reports, RPT_ERROR, "Tangent space can only be computed for tris/quads, aborting");
-      return;
-    }
-  }
-
-  /* Compute Mikktspace's tangent normals. */
-  mesh_to_tangent.mpolys = mpolys;
-  mesh_to_tangent.mloops = mloops;
-  mesh_to_tangent.mverts = mverts;
-  mesh_to_tangent.luvs = loopuvs;
-  mesh_to_tangent.lnors = loopnors;
-  mesh_to_tangent.tangents = r_looptangent;
-  mesh_to_tangent.num_polys = numPolys;
-
-  s_context.m_pUserData = &mesh_to_tangent;
-  s_context.m_pInterface = &s_interface;
-  s_interface.m_getNumFaces = get_num_faces;
-  s_interface.m_getNumVerticesOfFace = get_num_verts_of_face;
-  s_interface.m_getPosition = get_position;
-  s_interface.m_getTexCoord = get_texture_coordinate;
-  s_interface.m_getNormal = get_normal;
-  s_interface.m_setTSpaceBasic = set_tspace;
-
-  /* 0 if failed */
-  if (genTangSpaceDefault(&s_context) == false) {
-    BKE_report(reports, RPT_ERROR, "Mikktspace failed to generate tangents for this mesh!");
-  }
-}
-
-void BKE_mesh_calc_loop_tangent_single(Mesh *mesh,
-                                       const char *uvmap,
-                                       float (*r_looptangents)[4],
-                                       ReportList *reports)
-{
-  const MLoopUV *loopuvs;
-
-  /* Check we have valid texture coordinates first! */
-  if (uvmap) {
-    loopuvs = CustomData_get_layer_named(&mesh->ldata, CD_MLOOPUV, uvmap);
-  }
-  else {
-    loopuvs = CustomData_get_layer(&mesh->ldata, CD_MLOOPUV);
-  }
-  if (!loopuvs) {
-    BKE_reportf(reports,
-                RPT_ERROR,
-                "Tangent space computation needs a UV Map, \"%s\" not found, aborting",
-                uvmap);
-    return;
-  }
-
-  const float(*loopnors)[3] = CustomData_get_layer(&mesh->ldata, CD_NORMAL);
-  if (!loopnors) {
-    BKE_report(
-        reports, RPT_ERROR, "Tangent space computation needs loop normals, none found, aborting");
-    return;
-  }
-
-  BKE_mesh_calc_loop_tangent_single_ex(mesh->mvert,
-                                       mesh->totvert,
-                                       mesh->mloop,
-                                       r_looptangents,
-                                       loopnors,
-                                       loopuvs,
-                                       mesh->totloop,
-                                       mesh->mpoly,
-                                       mesh->totpoly,
-                                       reports);
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Mesh Tangent Calculations (All Layers)
- * \{ */
-
-/* Necessary complexity to handle looptri's as quads for correct tangents */
-#define USE_LOOPTRI_DETECT_QUADS
-
-typedef struct {
-  const float (*precomputedFaceNormals)[3];
-  const float (*precomputedLoopNormals)[3];
-  const MLoopTri *looptri;
-  const MLoopUV *mloopuv; /* texture coordinates */
-  const MPoly *mpoly;     /* indices */
-  const MLoop *mloop;     /* indices */
-  const MVert *mvert;     /* vertex coordinates */
-  const float (*vert_normals)[3];
-  const float (*orco)[3];
-  float (*tangent)[4]; /* destination */
-  int numTessFaces;
-
-#ifdef USE_LOOPTRI_DETECT_QUADS
-  /* map from 'fake' face index to looptri,
-   * quads will point to the first looptri of the quad */
-  const int *face_as_quad_map;
-  int num_face_as_quad_map;
-#endif
-
-} SGLSLMeshToTangent;
-
-/* interface */
-static int dm_ts_GetNumFaces(const SMikkTSpaceContext *pContext)
-{
-  SGLSLMeshToTangent *pMesh = pContext->m_pUserData;
-
-#ifdef USE_LOOPTRI_DETECT_QUADS
-  return pMesh->num_face_as_quad_map;
-#else
-  return pMesh->numTessFaces;
-#endif
-}
-
-static int dm_ts_GetNumVertsOfFace(const SMikkTSpaceContext *pContext, const int face_num)
-{
-#ifdef USE_LOOPTRI_DETECT_QUADS
-  SGLSLMeshToTangent *pMesh = pContext->m_pUserData;
-  if (pMesh->face_as_quad_map) {
-    const MLoopTri *lt = &pMesh->looptri[pMesh->face_as_quad_map[face_num]];
-    const MPoly *mp = &pMesh->mpoly[lt->poly];
-    if (mp->totloop == 4) {
-      return 4;
-    }
-  }
-  return 3;
-#else
-  UNUSED_VARS(pContext, face_num);
-  return 3;
-#endif
-}
-
-static void dm_ts_GetPosition(const SMikkTSpaceContext *pContext,
-                              float r_co[3],
-                              const int face_num,
-                              const int vert_index)
-{
-  // assert(vert_index >= 0 && vert_index < 4);
-  SGLSLMeshToTangent *pMesh = pContext->m_pUserData;
-  const MLoopTri *lt;
-  uint loop_index;
-  const float *co;
-
-#ifdef USE_LOOPTRI_DETECT_QUADS
-  if (pMesh->face_as_quad_map) {
-    lt = &pMesh->looptri[pMesh->face_as_quad_map[face_num]];
-    const MPoly *mp = &pMesh->mpoly[lt->poly];
-    if (mp->totloop == 4) {
-      loop_index = (uint)(mp->loopstart + vert_index);
-      goto finally;
-    }
-    /* fall through to regular triangle */
-  }
-  else {
-    lt = &pMesh->looptri[face_num];
-  }
-#else
-  lt = &pMesh->looptri[face_num];
-#endif
-  loop_index = lt->tri[vert_index];
-
-finally:
-  co = pMesh->mvert[pMesh->mloop[loop_index].v].co;
-  copy_v3_v3(r_co, co);
-}
-
-static void dm_ts_GetTextureCoordinate(const SMikkTSpaceContext *pContext,
-                                       float r_uv[2],
-                                       const int face_num,
-                                       const int vert_index)
-{
-  // assert(vert_index >= 0 && vert_index < 4);
-  SGLSLMeshToTangent *pMesh = pContext->m_pUserData;
-  const MLoopTri *lt;
-  uint loop_index;
-
-#ifdef USE_LOOPTRI_DETECT_QUADS
-  if (pMesh->face_as_quad_map) {
-    lt = &pMesh->looptri[pMesh->face_as_quad_map[face_num]];
-    const MPoly *mp = &pMesh->mpoly[lt->poly];
-    if (mp->totloop == 4) {
-      loop_index = (uint)(mp->loopstart + vert_index);
-      goto finally;
-    }
-    /* fall through to regular triangle */
-  }
-  else {
-    lt = &pMesh->looptri[face_num];
-  }
-#else
-  lt = &pMesh->looptri[face_num];
-#endif
-  loop_index = lt->tri[vert_index];
-
-finally:
-  if (pMesh->mloopuv != NULL) {
-    const float *uv = pMesh->mloopuv[loop_index].uv;
-    copy_v2_v2(r_uv, uv);
-  }
-  else {
-    const float *orco = pMesh->orco[pMesh->mloop[loop_index].v];
-    map_to_sphere(&r_uv[0], &r_uv[1], orco[0], orco[1], orco[2]);
-  }
-}
-
-static void dm_ts_GetNormal(const SMikkTSpaceContext *pContext,
-                            float r_no[3],
-                            const int face_num,
-                            const int vert_index)
-{
-  // assert(vert_index >= 0 && vert_index < 4);
-  SGLSLMeshToTangent *pMesh = (SGLSLMeshToTangent *)pContext->m_pUserData;
-  const MLoopTri *lt;
-  uint loop_index;
-
-#ifdef USE_LOOPTRI_DETECT_QUADS
-  if (pMesh->face_as_quad_map) {
-    lt = &pMesh->looptri[pMesh->face_as_quad_map[face_num]];
-    const MPoly *mp = &pMesh->mpoly[lt->poly];
-    if (mp->totloop == 4) {
-      loop_index = (uint)(mp->loopstart + vert_index);
-      goto finally;
-    }
-    /* fall through to regular triangle */
-  }
-  else {
-    lt = &pMesh->looptri[face_num];
-  }
-#else
-  lt = &pMesh->looptri[face_num];
-#endif
-  loop_index = lt->tri[vert_index];
-
-finally:
-  if (pMesh->precomputedLoopNormals) {
-    copy_v3_v3(r_no, pMesh->precomputedLoopNormals[loop_index]);
-  }
-  else if ((pMesh->mpoly[lt->poly].flag & ME_SMOOTH) == 0) { /* flat */
-    if (pMesh->precomputedFaceNormals) {
-      copy_v3_v3(r_no, pMesh->precomputedFaceNormals[lt->poly]);
-    }
-    else {
-#ifdef USE_LOOPTRI_DETECT_QUADS
-      const MPoly *mp = &pMesh->mpoly[lt->poly];
-      if (mp->totloop == 4) {
-        normal_quad_v3(r_no,
-                       pMesh->mvert[pMesh->mloop[mp->loopstart + 0].v].co,
-                       pMesh->mvert[pMesh->mloop[mp->loopstart + 1].v].co,
-                       pMesh->mvert[pMesh->mloop[mp->loopstart + 2].v].co,
-                       pMesh->mvert[pMesh->mloop[mp->loopstart + 3].v].co);
-      }
-      else
-#endif
-      {
-        normal_tri_v3(r_no,
-                      pMesh->mvert[pMesh->mloop[lt->tri[0]].v].co,
-                      pMesh->mvert[pMesh->mloop[lt->tri[1]].v].co,
-                      pMesh->mvert[pMesh->mloop[lt->tri[2]].v].co);
-      }
-    }
-  }
-  else {
-    copy_v3_v3(r_no, pMesh->vert_normals[pMesh->mloop[loop_index].v]);
-  }
-}
-
-static void dm_ts_SetTSpace(const SMikkTSpaceContext *pContext,
-                            const float fvTangent[3],
-                            const float fSign,
-                            const int face_num,
-                            const int vert_index)
-{
-  // assert(vert_index >= 0 && vert_index < 4);
-  SGLSLMeshToTangent *pMesh = (SGLSLMeshToTangent *)pContext->m_pUserData;
-  const MLoopTri *lt;
-  uint loop_index;
-
-#ifdef USE_LOOPTRI_DETECT_QUADS
-  if (pMesh->face_as_quad_map) {
-    lt = &pMesh->looptri[pMesh->face_as_quad_map[face_num]];
-    const MPoly *mp = &pMesh->mpoly[lt->poly];
-    if (mp->totloop == 4) {
-      loop_index = (uint)(mp->loopstart + vert_index);
-      goto finally;
-    }
-    /* fall through to regular triangle */
-  }
-  else {
-    lt = &pMesh->looptri[face_num];
-  }
-#else
-  lt = &pMesh->looptri[face_num];
-#endif
-  loop_index = lt->tri[vert_index];
-
-  float *pRes;
-
-finally:
-  pRes = pMesh->tangent[loop_index];
-  copy_v3_v3(pRes, fvTangent);
-  pRes[3] = fSign;
-}
-
-static void DM_calc_loop_tangents_thread(TaskPool *__restrict UNUSED(pool), void *taskdata)
-{
-  struct SGLSLMeshToTangent *mesh2tangent = taskdata;
-  /* new computation method */
-  {
-    SMikkTSpaceContext sContext = {NULL};
-    SMikkTSpaceInterface sInterface = {NULL};
-
-    sContext.m_pUserData = mesh2tangent;
-    sContext.m_pInterface = &sInterface;
-    sInterface.m_getNumFaces = dm_ts_GetNumFaces;
-    sInterface.m_getNumVerticesOfFace = dm_ts_GetNumVertsOfFace;
-    sInterface.m_getPosition = dm_ts_GetPosition;
-    sInterface.m_getTexCoord = dm_ts_GetTextureCoordinate;
-    sInterface.m_getNormal = dm_ts_GetNormal;
-    sInterface.m_setTSpaceBasic = dm_ts_SetTSpace;
-
-    /* 0 if failed */
-    genTangSpaceDefault(&sContext);
-  }
-}
-
-void BKE_mesh_add_loop_tangent_named_layer_for_uv(CustomData *uv_data,
-                                                  CustomData *tan_data,
-                                                  int numLoopData,
-                                                  const char *layer_name)
-{
-  if (CustomData_get_named_layer_index(tan_data, CD_TANGENT, layer_name) == -1 &&
-      CustomData_get_named_layer_index(uv_data, CD_MLOOPUV, layer_name) != -1) {
-    CustomData_add_layer_named(tan_data, CD_TANGENT, CD_CALLOC, NULL, numLoopData, layer_name);
-  }
-}
-
-void BKE_mesh_calc_loop_tangent_step_0(const CustomData *loopData,
-                                       bool calc_active_tangent,
-                                       const char (*tangent_names)[MAX_NAME],
-                                       int tangent_names_count,
-                                       bool *rcalc_act,
-                                       bool *rcalc_ren,
-                                       int *ract_uv_n,
-                                       int *rren_uv_n,
-                                       char *ract_uv_name,
-                                       char *rren_uv_name,
-                                       short *rtangent_mask)
-{
-  /* Active uv in viewport */
-  int layer_index = CustomData_get_layer_index(loopData, CD_MLOOPUV);
-  *ract_uv_n = CustomData_get_active_layer(loopData, CD_MLOOPUV);
-  ract_uv_name[0] = 0;
-  if (*ract_uv_n != -1) {
-    strcpy(ract_uv_name, loopData->layers[*ract_uv_n + layer_index].name);
-  }
-
-  /* Active tangent in render */
-  *rren_uv_n = CustomData_get_render_layer(loopData, CD_MLOOPUV);
-  rren_uv_name[0] = 0;
-  if (*rren_uv_n != -1) {
-    strcpy(rren_uv_name, loopData->layers[*rren_uv_n + layer_index].name);
-  }
-
-  /* If active tangent not in tangent_names we take it into account */
-  *rcalc_act = false;
-  *rcalc_ren = false;
-  for (int i = 0; i < tangent_names_count; i++) {
-    if (tangent_names[i][0] == 0) {
-      calc_active_tangent = true;
-    }
-  }
-  if (calc_active_tangent) {
-    *rcalc_act = true;
-    *rcalc_ren = true;
-    for (int i = 0; i < tangent_names_count; i++) {
-      if (STREQ(ract_uv_name, tangent_names[i])) {
-        *rcalc_act = false;
-      }
-      if (STREQ(rren_uv_name, tangent_names[i])) {
-        *rcalc_ren = false;
-      }
-    }
-  }
-  *rtangent_mask = 0;
-
-  const int uv_layer_num = CustomData_number_of_layers(loopData, CD_MLOOPUV);
-  for (int n = 0; n < uv_layer_num; n++) {
-    const char *name = CustomData_get_layer_name(loopData, CD_MLOOPUV, n);
-    bool add = false;
-    for (int i = 0; i < tangent_names_count; i++) {
-      if (tangent_names[i][0] && STREQ(tangent_names[i], name)) {
-        add = true;
-        break;
-      }
-    }
-    if (!add && ((*rcalc_act && ract_uv_name[0] && STREQ(ract_uv_name, name)) ||
-                 (*rcalc_ren && rren_uv_name[0] && STREQ(rren_uv_name, name)))) {
-      add = true;
-    }
-    if (add) {
-      *rtangent_mask |= (short)(1 << n);
-    }
-  }
-
-  if (uv_layer_num == 0) {
-    *rtangent_mask |= DM_TANGENT_MASK_ORCO;
-  }
-}
-
-void BKE_mesh_calc_loop_tangent_ex(const MVert *mvert,
-                                   const MPoly *mpoly,
-                                   const uint mpoly_len,
-                                   const MLoop *mloop,
-                                   const MLoopTri *looptri,
-                                   const uint looptri_len,
-
-                                   CustomData *loopdata,
-                                   bool calc_active_tangent,
-                                   const char (*tangent_names)[MAX_NAME],
-                                   int tangent_names_len,
-                                   const float (*vert_normals)[3],
-                                   const float (*poly_normals)[3],
-                                   const float (*loop_normals)[3],
-                                   const float (*vert_orco)[3],
-                                   /* result */
-                                   CustomData *loopdata_out,
-                                   const uint loopdata_out_len,
-                                   short *tangent_mask_curr_p)
-{
-  int act_uv_n = -1;
-  int ren_uv_n = -1;
-  bool calc_act = false;
-  bool calc_ren = false;
-  char act_uv_name[MAX_NAME];
-  char ren_uv_name[MAX_NAME];
-  short tangent_mask = 0;
-  short tangent_mask_curr = *tangent_mask_curr_p;
-
-  BKE_mesh_calc_loop_tangent_step_0(loopdata,
-                                    calc_active_tangent,
-                                    tangent_names,
-                                    tangent_names_len,
-                                    &calc_act,
-                                    &calc_ren,
-                                    &act_uv_n,
-                                    &ren_uv_n,
-                                    act_uv_name,
-                                    ren_uv_name,
-                                    &tangent_mask);
-  if ((tangent_mask_curr | tangent_mask) != tangent_mask_curr) {
-    /* Check we have all the needed layers */
-    /* Allocate needed tangent layers */
-    for (int i = 0; i < tangent_names_len; i++) {
-      if (tangent_names[i][0]) {
-        BKE_mesh_add_loop_tangent_named_layer_for_uv(
-            loopdata, loopdata_out, (int)loopdata_out_len, tangent_names[i]);
-      }
-    }
-    if ((tangent_mask & DM_TANGENT_MASK_ORCO) &&
-        CustomData_get_named_layer_index(loopdata, CD_TANGENT, "") == -1) {
-      CustomData_add_layer_named(
-          loopdata_out, CD_TANGENT, CD_CALLOC, NULL, (int)loopdata_out_len, "");
-    }
-    if (calc_act && act_uv_name[0]) {
-      BKE_mesh_add_loop_tangent_named_layer_for_uv(
-          loopdata, loopdata_out, (int)loopdata_out_len, act_uv_name);
-    }
-    if (calc_ren && ren_uv_name[0]) {
-      BKE_mesh_add_loop_tangent_named_layer_for_uv(
-          loopdata, loopdata_out, (int)loopdata_out_len, ren_uv_name);
-    }
-
-#ifdef USE_LOOPTRI_DETECT_QUADS
-    int num_face_as_quad_map;
-    int *face_as_quad_map = NULL;
-
-    /* map faces to quads */
-    if (looptri_len != mpoly_len) {
-      /* Over allocate, since we don't know how many ngon or quads we have. */
-
-      /* map fake face index to looptri */
-      face_as_quad_map = MEM_mallocN(sizeof(int) * looptri_len, __func__);
-      int k, j;
-      for (k = 0, j = 0; j < (int)looptri_len; k++, j++) {
-        face_as_quad_map[k] = j;
-        /* step over all quads */
-        if (mpoly[looptri[j].poly].totloop == 4) {
-          j++; /* skips the nest looptri */
-        }
-      }
-      num_face_as_quad_map = k;
-    }
-    else {
-      num_face_as_quad_map = (int)looptri_len;
-    }
-#endif
-
-    /* Calculation */
-    if (looptri_len != 0) {
-      TaskPool *task_pool = BLI_task_pool_create(NULL, TASK_PRIORITY_HIGH);
-
-      tangent_mask_curr = 0;
-      /* Calculate tangent layers */
-      SGLSLMeshToTangent data_array[MAX_MTFACE];
-      const int tangent_layer_num = CustomData_number_of_layers(loopdata_out, CD_TANGENT);
-      for (int n = 0; n < tangent_layer_num; n++) {
-        int index = CustomData_get_layer_index_n(loopdata_out, CD_TANGENT, n);
-        BLI_assert(n < MAX_MTFACE);
-        SGLSLMeshToTangent *mesh2tangent = &data_array[n];
-        mesh2tangent->numTessFaces = (int)looptri_len;
-#ifdef USE_LOOPTRI_DETECT_QUADS
-        mesh2tangent->face_as_quad_map = face_as_quad_map;
-        mesh2tangent->num_face_as_quad_map = num_face_as_quad_map;
-#endif
-        mesh2tangent->mvert = mvert;
-        mesh2tangent->vert_normals = vert_normals;
-        mesh2tangent->mpoly = mpoly;
-        mesh2tangent->mloop = mloop;
-        mesh2tangent->looptri = looptri;
-        /* NOTE: we assume we do have tessellated loop normals at this point
-         * (in case it is object-enabled), have to check this is valid. */
-        mesh2tangent->precomputedLoopNormals = loop_normals;
-        mesh2tangent->precomputedFaceNormals = poly_normals;
-
-        mesh2tangent->orco = NULL;
-        mesh2tangent->mloopuv = CustomData_get_layer_named(
-            loopdata, CD_MLOOPUV, loopdata_out->layers[index].name);
-
-        /* Fill the resulting tangent_mask */
-        if (!mesh2tangent->mloopuv) {
-          mesh2tangent->orco = vert_orco;
-          if (!mesh2tangent->orco) {
-            continue;
-          }
-
-          tangent_mask_curr |= DM_TANGENT_MASK_ORCO;
-        }
-        else {
-          int uv_ind = CustomData_get_named_layer_index(
-              loopdata, CD_MLOOPUV, loopdata_out->layers[index].name);
-          int uv_start = CustomData_get_layer_index(loopdata, CD_MLOOPUV);
-          BLI_assert(uv_ind != -1 && uv_start != -1);
-          BLI_assert(uv_ind - uv_start < MAX_MTFACE);
-          tangent_mask_curr |= (short)(1 << (uv_ind - uv_start));
-        }
-
-        mesh2tangent->tangent = loopdata_out->layers[index].data;
-        BLI_task_pool_push(task_pool, DM_calc_loop_tangents_thread, mesh2tangent, false, NULL);
-      }
-
-      BLI_assert(tangent_mask_curr == tangent_mask);
-      BLI_task_pool_work_and_wait(task_pool);
-      BLI_task_pool_free(task_pool);
-    }
-    else {
-      tangent_mask_curr = tangent_mask;
-    }
-#ifdef USE_LOOPTRI_DETECT_QUADS
-    if (face_as_quad_map) {
-      MEM_freeN(face_as_quad_map);
-    }
-#  undef USE_LOOPTRI_DETECT_QUADS
-
-#endif
-
-    *tangent_mask_curr_p = tangent_mask_curr;
-
-    /* Update active layer index */
-    int act_uv_index = (act_uv_n != -1) ?
-                           CustomData_get_layer_index_n(loopdata, CD_MLOOPUV, act_uv_n) :
-                           -1;
-    if (act_uv_index != -1) {
-      int tan_index = CustomData_get_named_layer_index(
-          loopdata, CD_TANGENT, loopdata->layers[act_uv_index].name);
-      CustomData_set_layer_active_index(loopdata, CD_TANGENT, tan_index);
-    } /* else tangent has been built from orco */
-
-    /* Update render layer index */
-    int ren_uv_index = (ren_uv_n != -1) ?
-                           CustomData_get_layer_index_n(loopdata, CD_MLOOPUV, ren_uv_n) :
-                           -1;
-    if (ren_uv_index != -1) {
-      int tan_index = CustomData_get_named_layer_index(
-          loopdata, CD_TANGENT, loopdata->layers[ren_uv_index].name);
-      CustomData_set_layer_render_index(loopdata, CD_TANGENT, tan_index);
-    } /* else tangent has been built from orco */
-  }
-}
-
-void BKE_mesh_calc_loop_tangents(Mesh *me_eval,
-                                 bool calc_active_tangent,
-                                 const char (*tangent_names)[MAX_NAME],
-                                 int tangent_names_len)
-{
-  BKE_mesh_runtime_looptri_ensure(me_eval);
-
-  /* TODO(campbell): store in Mesh.runtime to avoid recalculation. */
-  short tangent_mask = 0;
-  BKE_mesh_calc_loop_tangent_ex(me_eval->mvert,
-                                me_eval->mpoly,
-                                (uint)me_eval->totpoly,
-                                me_eval->mloop,
-                                me_eval->runtime.looptris.array,
-                                (uint)me_eval->runtime.looptris.len,
-                                &me_eval->ldata,
-                                calc_active_tangent,
-                                tangent_names,
-                                tangent_names_len,
-                                BKE_mesh_vertex_normals_ensure(me_eval),
-                                BKE_mesh_poly_normals_ensure(me_eval),
-                                CustomData_get_layer(&me_eval->ldata, CD_NORMAL),
-                                CustomData_get_layer(&me_eval->vdata, CD_ORCO), /* may be NULL */
-                                /* result */
-                                &me_eval->ldata,
-                                (uint)me_eval->totloop,
-                                &tangent_mask);
-}
-
-/** \} */
diff --git a/source/blender/blenkernel/intern/mesh_tangent.cc b/source/blender/blenkernel/intern/mesh_tangent.cc
new file mode 100644
index 00000000000..8f9af5e9258
--- /dev/null
+++ b/source/blender/blenkernel/intern/mesh_tangent.cc
@@ -0,0 +1,605 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright 2001-2002 NaN Holding BV. All rights reserved. */
+
+/** \file
+ * \ingroup bke
+ *
+ * Functions to evaluate mesh tangents.
+ */
+
+#include 
+
+#include "MEM_guardedalloc.h"
+
+#include "DNA_mesh_types.h"
+#include "DNA_meshdata_types.h"
+
+#include "BLI_math.h"
+#include "BLI_task.h"
+#include "BLI_utildefines.h"
+
+#include "BKE_customdata.h"
+#include "BKE_mesh.h"
+#include "BKE_mesh_runtime.h"
+#include "BKE_mesh_tangent.h"
+#include "BKE_report.h"
+
+#include "BLI_strict_flags.h"
+
+#include "atomic_ops.h"
+#include "mikktspace.hh"
+
+/* -------------------------------------------------------------------- */
+/** \name Mesh Tangent Calculations (Single Layer)
+ * \{ */
+
+struct BKEMeshToTangent {
+  uint GetNumFaces()
+  {
+    return (uint)num_polys;
+  }
+
+  uint GetNumVerticesOfFace(const uint face_num)
+  {
+    return (uint)mpolys[face_num].totloop;
+  }
+
+  mikk::float3 GetPosition(const uint face_num, const uint vert_num)
+  {
+    const uint loop_idx = (uint)mpolys[face_num].loopstart + vert_num;
+    return mikk::float3(mverts[mloops[loop_idx].v].co);
+  }
+
+  mikk::float3 GetTexCoord(const uint face_num, const uint vert_num)
+  {
+    const float *uv = luvs[(uint)mpolys[face_num].loopstart + vert_num].uv;
+    return mikk::float3(uv[0], uv[1], 1.0f);
+  }
+
+  mikk::float3 GetNormal(const uint face_num, const uint vert_num)
+  {
+    return mikk::float3(lnors[(uint)mpolys[face_num].loopstart + vert_num]);
+  }
+
+  void SetTangentSpace(const uint face_num, const uint vert_num, mikk::float3 T, bool orientation)
+  {
+    float *p_res = tangents[(uint)mpolys[face_num].loopstart + vert_num];
+    copy_v4_fl4(p_res, T.x, T.y, T.z, orientation ? 1.0f : -1.0f);
+  }
+
+  const MPoly *mpolys;     /* faces */
+  const MLoop *mloops;     /* faces vertices */
+  const MVert *mverts;     /* vertices */
+  const MLoopUV *luvs;     /* texture coordinates */
+  const float (*lnors)[3]; /* loops' normals */
+  float (*tangents)[4];    /* output tangents */
+  int num_polys;           /* number of polygons */
+};
+
+void BKE_mesh_calc_loop_tangent_single_ex(const MVert *mverts,
+                                          const int UNUSED(numVerts),
+                                          const MLoop *mloops,
+                                          float (*r_looptangent)[4],
+                                          const float (*loopnors)[3],
+                                          const MLoopUV *loopuvs,
+                                          const int UNUSED(numLoops),
+                                          const MPoly *mpolys,
+                                          const int numPolys,
+                                          ReportList *reports)
+{
+  /* Compute Mikktspace's tangent normals. */
+  BKEMeshToTangent mesh_to_tangent;
+  mesh_to_tangent.mpolys = mpolys;
+  mesh_to_tangent.mloops = mloops;
+  mesh_to_tangent.mverts = mverts;
+  mesh_to_tangent.luvs = loopuvs;
+  mesh_to_tangent.lnors = loopnors;
+  mesh_to_tangent.tangents = r_looptangent;
+  mesh_to_tangent.num_polys = numPolys;
+
+  mikk::Mikktspace mikk(mesh_to_tangent);
+
+  /* First check we do have a tris/quads only mesh. */
+  for (int i = 0; i < numPolys; i++) {
+    if (mpolys[i].totloop > 4) {
+      BKE_report(
+          reports, RPT_ERROR, "Tangent space can only be computed for tris/quads, aborting");
+      return;
+    }
+  }
+
+  mikk.genTangSpace();
+}
+
+void BKE_mesh_calc_loop_tangent_single(Mesh *mesh,
+                                       const char *uvmap,
+                                       float (*r_looptangents)[4],
+                                       ReportList *reports)
+{
+  const MLoopUV *loopuvs;
+
+  /* Check we have valid texture coordinates first! */
+  if (uvmap) {
+    loopuvs = static_cast(CustomData_get_layer_named(&mesh->ldata, CD_MLOOPUV, uvmap));
+  }
+  else {
+    loopuvs = static_cast(CustomData_get_layer(&mesh->ldata, CD_MLOOPUV));
+  }
+  if (!loopuvs) {
+    BKE_reportf(reports,
+                RPT_ERROR,
+                "Tangent space computation needs a UV Map, \"%s\" not found, aborting",
+                uvmap);
+    return;
+  }
+
+  const float(*loopnors)[3] = static_cast(
+      CustomData_get_layer(&mesh->ldata, CD_NORMAL));
+  if (!loopnors) {
+    BKE_report(
+        reports, RPT_ERROR, "Tangent space computation needs loop normals, none found, aborting");
+    return;
+  }
+
+  BKE_mesh_calc_loop_tangent_single_ex(BKE_mesh_verts(mesh),
+                                       mesh->totvert,
+                                       BKE_mesh_loops(mesh),
+                                       r_looptangents,
+                                       loopnors,
+                                       loopuvs,
+                                       mesh->totloop,
+                                       BKE_mesh_polys(mesh),
+                                       mesh->totpoly,
+                                       reports);
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Mesh Tangent Calculations (All Layers)
+ * \{ */
+
+/* Necessary complexity to handle looptri's as quads for correct tangents */
+#define USE_LOOPTRI_DETECT_QUADS
+
+struct SGLSLMeshToTangent {
+  uint GetNumFaces()
+  {
+#ifdef USE_LOOPTRI_DETECT_QUADS
+    return (uint)num_face_as_quad_map;
+#else
+    return (uint)numTessFaces;
+#endif
+  }
+
+  uint GetNumVerticesOfFace(const uint face_num)
+  {
+#ifdef USE_LOOPTRI_DETECT_QUADS
+    if (face_as_quad_map) {
+      const MLoopTri *lt = &looptri[face_as_quad_map[face_num]];
+      const MPoly *mp = &mpoly[lt->poly];
+      if (mp->totloop == 4) {
+        return 4;
+      }
+    }
+    return 3;
+#else
+    UNUSED_VARS(pContext, face_num);
+    return 3;
+#endif
+  }
+
+  uint GetLoop(const uint face_num, const uint vert_num, const MLoopTri *<)
+  {
+#ifdef USE_LOOPTRI_DETECT_QUADS
+    if (face_as_quad_map) {
+      lt = &looptri[face_as_quad_map[face_num]];
+      const MPoly *mp = &mpoly[lt->poly];
+      if (mp->totloop == 4) {
+        return ((uint)mp->loopstart + vert_num);
+      }
+      /* fall through to regular triangle */
+    }
+    else {
+      lt = &looptri[face_num];
+    }
+#else
+    lt = &looptri[face_num];
+#endif
+    return lt->tri[vert_num];
+  }
+
+  mikk::float3 GetPosition(const uint face_num, const uint vert_num)
+  {
+    const MLoopTri *lt;
+    uint loop_index = GetLoop(face_num, vert_num, lt);
+    return mikk::float3(mvert[mloop[loop_index].v].co);
+  }
+
+  mikk::float3 GetTexCoord(const uint face_num, const uint vert_num)
+  {
+    const MLoopTri *lt;
+    uint loop_index = GetLoop(face_num, vert_num, lt);
+    if (mloopuv != nullptr) {
+      const float *uv = mloopuv[loop_index].uv;
+      return mikk::float3(uv[0], uv[1], 1.0f);
+    }
+    else {
+      const float *l_orco = orco[mloop[loop_index].v];
+      float u, v;
+      map_to_sphere(&u, &v, l_orco[0], l_orco[1], l_orco[2]);
+      return mikk::float3(u, v, 1.0f);
+    }
+  }
+
+  mikk::float3 GetNormal(const uint face_num, const uint vert_num)
+  {
+    const MLoopTri *lt;
+    uint loop_index = GetLoop(face_num, vert_num, lt);
+    if (precomputedLoopNormals) {
+      return mikk::float3(precomputedLoopNormals[loop_index]);
+    }
+    else if ((mpoly[lt->poly].flag & ME_SMOOTH) == 0) { /* flat */
+      if (precomputedFaceNormals) {
+        return mikk::float3(precomputedFaceNormals[lt->poly]);
+      }
+      else {
+#ifdef USE_LOOPTRI_DETECT_QUADS
+        const MPoly *mp = &mpoly[lt->poly];
+        float normal[3];
+        if (mp->totloop == 4) {
+          normal_quad_v3(normal,
+                         mvert[mloop[mp->loopstart + 0].v].co,
+                         mvert[mloop[mp->loopstart + 1].v].co,
+                         mvert[mloop[mp->loopstart + 2].v].co,
+                         mvert[mloop[mp->loopstart + 3].v].co);
+        }
+        else
+#endif
+        {
+          normal_tri_v3(normal,
+                        mvert[mloop[lt->tri[0]].v].co,
+                        mvert[mloop[lt->tri[1]].v].co,
+                        mvert[mloop[lt->tri[2]].v].co);
+        }
+        return mikk::float3(normal);
+      }
+    }
+    else {
+      return mikk::float3(vert_normals[mloop[loop_index].v]);
+    }
+  }
+
+  void SetTangentSpace(const uint face_num, const uint vert_num, mikk::float3 T, bool orientation)
+  {
+    const MLoopTri *lt;
+    uint loop_index = GetLoop(face_num, vert_num, lt);
+
+    copy_v4_fl4(tangent[loop_index], T.x, T.y, T.z, orientation ? 1.0f : -1.0f);
+  }
+
+  const float (*precomputedFaceNormals)[3];
+  const float (*precomputedLoopNormals)[3];
+  const MLoopTri *looptri;
+  const MLoopUV *mloopuv; /* texture coordinates */
+  const MPoly *mpoly;     /* indices */
+  const MLoop *mloop;     /* indices */
+  const MVert *mvert;     /* vertex coordinates */
+  const float (*vert_normals)[3];
+  const float (*orco)[3];
+  float (*tangent)[4]; /* destination */
+  int numTessFaces;
+
+#ifdef USE_LOOPTRI_DETECT_QUADS
+  /* map from 'fake' face index to looptri,
+   * quads will point to the first looptri of the quad */
+  const int *face_as_quad_map;
+  int num_face_as_quad_map;
+#endif
+};
+
+static void DM_calc_loop_tangents_thread(TaskPool *__restrict UNUSED(pool), void *taskdata)
+{
+  SGLSLMeshToTangent *mesh_data = static_cast(taskdata);
+
+  mikk::Mikktspace mikk(*mesh_data);
+  mikk.genTangSpace();
+}
+
+void BKE_mesh_add_loop_tangent_named_layer_for_uv(CustomData *uv_data,
+                                                  CustomData *tan_data,
+                                                  int numLoopData,
+                                                  const char *layer_name)
+{
+  if (CustomData_get_named_layer_index(tan_data, CD_TANGENT, layer_name) == -1 &&
+      CustomData_get_named_layer_index(uv_data, CD_MLOOPUV, layer_name) != -1) {
+    CustomData_add_layer_named(
+        tan_data, CD_TANGENT, CD_SET_DEFAULT, nullptr, numLoopData, layer_name);
+  }
+}
+
+void BKE_mesh_calc_loop_tangent_step_0(const CustomData *loopData,
+                                       bool calc_active_tangent,
+                                       const char (*tangent_names)[MAX_NAME],
+                                       int tangent_names_count,
+                                       bool *rcalc_act,
+                                       bool *rcalc_ren,
+                                       int *ract_uv_n,
+                                       int *rren_uv_n,
+                                       char *ract_uv_name,
+                                       char *rren_uv_name,
+                                       short *rtangent_mask)
+{
+  /* Active uv in viewport */
+  int layer_index = CustomData_get_layer_index(loopData, CD_MLOOPUV);
+  *ract_uv_n = CustomData_get_active_layer(loopData, CD_MLOOPUV);
+  ract_uv_name[0] = 0;
+  if (*ract_uv_n != -1) {
+    strcpy(ract_uv_name, loopData->layers[*ract_uv_n + layer_index].name);
+  }
+
+  /* Active tangent in render */
+  *rren_uv_n = CustomData_get_render_layer(loopData, CD_MLOOPUV);
+  rren_uv_name[0] = 0;
+  if (*rren_uv_n != -1) {
+    strcpy(rren_uv_name, loopData->layers[*rren_uv_n + layer_index].name);
+  }
+
+  /* If active tangent not in tangent_names we take it into account */
+  *rcalc_act = false;
+  *rcalc_ren = false;
+  for (int i = 0; i < tangent_names_count; i++) {
+    if (tangent_names[i][0] == 0) {
+      calc_active_tangent = true;
+    }
+  }
+  if (calc_active_tangent) {
+    *rcalc_act = true;
+    *rcalc_ren = true;
+    for (int i = 0; i < tangent_names_count; i++) {
+      if (STREQ(ract_uv_name, tangent_names[i])) {
+        *rcalc_act = false;
+      }
+      if (STREQ(rren_uv_name, tangent_names[i])) {
+        *rcalc_ren = false;
+      }
+    }
+  }
+  *rtangent_mask = 0;
+
+  const int uv_layer_num = CustomData_number_of_layers(loopData, CD_MLOOPUV);
+  for (int n = 0; n < uv_layer_num; n++) {
+    const char *name = CustomData_get_layer_name(loopData, CD_MLOOPUV, n);
+    bool add = false;
+    for (int i = 0; i < tangent_names_count; i++) {
+      if (tangent_names[i][0] && STREQ(tangent_names[i], name)) {
+        add = true;
+        break;
+      }
+    }
+    if (!add && ((*rcalc_act && ract_uv_name[0] && STREQ(ract_uv_name, name)) ||
+                 (*rcalc_ren && rren_uv_name[0] && STREQ(rren_uv_name, name)))) {
+      add = true;
+    }
+    if (add) {
+      *rtangent_mask |= (short)(1 << n);
+    }
+  }
+
+  if (uv_layer_num == 0) {
+    *rtangent_mask |= DM_TANGENT_MASK_ORCO;
+  }
+}
+
+void BKE_mesh_calc_loop_tangent_ex(const MVert *mvert,
+                                   const MPoly *mpoly,
+                                   const uint mpoly_len,
+                                   const MLoop *mloop,
+                                   const MLoopTri *looptri,
+                                   const uint looptri_len,
+
+                                   CustomData *loopdata,
+                                   bool calc_active_tangent,
+                                   const char (*tangent_names)[MAX_NAME],
+                                   int tangent_names_len,
+                                   const float (*vert_normals)[3],
+                                   const float (*poly_normals)[3],
+                                   const float (*loop_normals)[3],
+                                   const float (*vert_orco)[3],
+                                   /* result */
+                                   CustomData *loopdata_out,
+                                   const uint loopdata_out_len,
+                                   short *tangent_mask_curr_p)
+{
+  int act_uv_n = -1;
+  int ren_uv_n = -1;
+  bool calc_act = false;
+  bool calc_ren = false;
+  char act_uv_name[MAX_NAME];
+  char ren_uv_name[MAX_NAME];
+  short tangent_mask = 0;
+  short tangent_mask_curr = *tangent_mask_curr_p;
+
+  BKE_mesh_calc_loop_tangent_step_0(loopdata,
+                                    calc_active_tangent,
+                                    tangent_names,
+                                    tangent_names_len,
+                                    &calc_act,
+                                    &calc_ren,
+                                    &act_uv_n,
+                                    &ren_uv_n,
+                                    act_uv_name,
+                                    ren_uv_name,
+                                    &tangent_mask);
+  if ((tangent_mask_curr | tangent_mask) != tangent_mask_curr) {
+    /* Check we have all the needed layers */
+    /* Allocate needed tangent layers */
+    for (int i = 0; i < tangent_names_len; i++) {
+      if (tangent_names[i][0]) {
+        BKE_mesh_add_loop_tangent_named_layer_for_uv(
+            loopdata, loopdata_out, (int)loopdata_out_len, tangent_names[i]);
+      }
+    }
+    if ((tangent_mask & DM_TANGENT_MASK_ORCO) &&
+        CustomData_get_named_layer_index(loopdata, CD_TANGENT, "") == -1) {
+      CustomData_add_layer_named(
+          loopdata_out, CD_TANGENT, CD_SET_DEFAULT, nullptr, (int)loopdata_out_len, "");
+    }
+    if (calc_act && act_uv_name[0]) {
+      BKE_mesh_add_loop_tangent_named_layer_for_uv(
+          loopdata, loopdata_out, (int)loopdata_out_len, act_uv_name);
+    }
+    if (calc_ren && ren_uv_name[0]) {
+      BKE_mesh_add_loop_tangent_named_layer_for_uv(
+          loopdata, loopdata_out, (int)loopdata_out_len, ren_uv_name);
+    }
+
+#ifdef USE_LOOPTRI_DETECT_QUADS
+    int num_face_as_quad_map;
+    int *face_as_quad_map = nullptr;
+
+    /* map faces to quads */
+    if (looptri_len != mpoly_len) {
+      /* Over allocate, since we don't know how many ngon or quads we have. */
+
+      /* map fake face index to looptri */
+      face_as_quad_map = static_cast(MEM_mallocN(sizeof(int) * looptri_len, __func__));
+      int k, j;
+      for (k = 0, j = 0; j < (int)looptri_len; k++, j++) {
+        face_as_quad_map[k] = j;
+        /* step over all quads */
+        if (mpoly[looptri[j].poly].totloop == 4) {
+          j++; /* skips the nest looptri */
+        }
+      }
+      num_face_as_quad_map = k;
+    }
+    else {
+      num_face_as_quad_map = (int)looptri_len;
+    }
+#endif
+
+    /* Calculation */
+    if (looptri_len != 0) {
+      TaskPool *task_pool = BLI_task_pool_create(nullptr, TASK_PRIORITY_HIGH);
+
+      tangent_mask_curr = 0;
+      /* Calculate tangent layers */
+      SGLSLMeshToTangent data_array[MAX_MTFACE];
+      const int tangent_layer_num = CustomData_number_of_layers(loopdata_out, CD_TANGENT);
+      for (int n = 0; n < tangent_layer_num; n++) {
+        int index = CustomData_get_layer_index_n(loopdata_out, CD_TANGENT, n);
+        BLI_assert(n < MAX_MTFACE);
+        SGLSLMeshToTangent *mesh2tangent = &data_array[n];
+        mesh2tangent->numTessFaces = (int)looptri_len;
+#ifdef USE_LOOPTRI_DETECT_QUADS
+        mesh2tangent->face_as_quad_map = face_as_quad_map;
+        mesh2tangent->num_face_as_quad_map = num_face_as_quad_map;
+#endif
+        mesh2tangent->mvert = mvert;
+        mesh2tangent->vert_normals = vert_normals;
+        mesh2tangent->mpoly = mpoly;
+        mesh2tangent->mloop = mloop;
+        mesh2tangent->looptri = looptri;
+        /* NOTE: we assume we do have tessellated loop normals at this point
+         * (in case it is object-enabled), have to check this is valid. */
+        mesh2tangent->precomputedLoopNormals = loop_normals;
+        mesh2tangent->precomputedFaceNormals = poly_normals;
+
+        mesh2tangent->orco = nullptr;
+        mesh2tangent->mloopuv = static_cast(
+            CustomData_get_layer_named(loopdata, CD_MLOOPUV, loopdata_out->layers[index].name));
+
+        /* Fill the resulting tangent_mask */
+        if (!mesh2tangent->mloopuv) {
+          mesh2tangent->orco = vert_orco;
+          if (!mesh2tangent->orco) {
+            continue;
+          }
+
+          tangent_mask_curr |= DM_TANGENT_MASK_ORCO;
+        }
+        else {
+          int uv_ind = CustomData_get_named_layer_index(
+              loopdata, CD_MLOOPUV, loopdata_out->layers[index].name);
+          int uv_start = CustomData_get_layer_index(loopdata, CD_MLOOPUV);
+          BLI_assert(uv_ind != -1 && uv_start != -1);
+          BLI_assert(uv_ind - uv_start < MAX_MTFACE);
+          tangent_mask_curr |= (short)(1 << (uv_ind - uv_start));
+        }
+
+        mesh2tangent->tangent = static_cast(loopdata_out->layers[index].data);
+        BLI_task_pool_push(task_pool, DM_calc_loop_tangents_thread, mesh2tangent, false, nullptr);
+      }
+
+      BLI_assert(tangent_mask_curr == tangent_mask);
+      BLI_task_pool_work_and_wait(task_pool);
+      BLI_task_pool_free(task_pool);
+    }
+    else {
+      tangent_mask_curr = tangent_mask;
+    }
+#ifdef USE_LOOPTRI_DETECT_QUADS
+    if (face_as_quad_map) {
+      MEM_freeN(face_as_quad_map);
+    }
+#  undef USE_LOOPTRI_DETECT_QUADS
+
+#endif
+
+    *tangent_mask_curr_p = tangent_mask_curr;
+
+    /* Update active layer index */
+    int act_uv_index = (act_uv_n != -1) ?
+                           CustomData_get_layer_index_n(loopdata, CD_MLOOPUV, act_uv_n) :
+                           -1;
+    if (act_uv_index != -1) {
+      int tan_index = CustomData_get_named_layer_index(
+          loopdata, CD_TANGENT, loopdata->layers[act_uv_index].name);
+      CustomData_set_layer_active_index(loopdata, CD_TANGENT, tan_index);
+    } /* else tangent has been built from orco */
+
+    /* Update render layer index */
+    int ren_uv_index = (ren_uv_n != -1) ?
+                           CustomData_get_layer_index_n(loopdata, CD_MLOOPUV, ren_uv_n) :
+                           -1;
+    if (ren_uv_index != -1) {
+      int tan_index = CustomData_get_named_layer_index(
+          loopdata, CD_TANGENT, loopdata->layers[ren_uv_index].name);
+      CustomData_set_layer_render_index(loopdata, CD_TANGENT, tan_index);
+    } /* else tangent has been built from orco */
+  }
+}
+
+void BKE_mesh_calc_loop_tangents(Mesh *me_eval,
+                                 bool calc_active_tangent,
+                                 const char (*tangent_names)[MAX_NAME],
+                                 int tangent_names_len)
+{
+  BKE_mesh_runtime_looptri_ensure(me_eval);
+
+  /* TODO(@campbellbarton): store in Mesh.runtime to avoid recalculation. */
+  short tangent_mask = 0;
+  BKE_mesh_calc_loop_tangent_ex(
+      BKE_mesh_verts(me_eval),
+      BKE_mesh_polys(me_eval),
+      (uint)me_eval->totpoly,
+      BKE_mesh_loops(me_eval),
+      me_eval->runtime.looptris.array,
+      (uint)me_eval->runtime.looptris.len,
+      &me_eval->ldata,
+      calc_active_tangent,
+      tangent_names,
+      tangent_names_len,
+      BKE_mesh_vertex_normals_ensure(me_eval),
+      BKE_mesh_poly_normals_ensure(me_eval),
+      static_cast(CustomData_get_layer(&me_eval->ldata, CD_NORMAL)),
+      /* may be nullptr */
+      static_cast(CustomData_get_layer(&me_eval->vdata, CD_ORCO)),
+      /* result */
+      &me_eval->ldata,
+      (uint)me_eval->totloop,
+      &tangent_mask);
+}
+
+/** \} */
diff --git a/source/blender/blenkernel/intern/mesh_tessellate.c b/source/blender/blenkernel/intern/mesh_tessellate.c
deleted file mode 100644
index 173fb98912b..00000000000
--- a/source/blender/blenkernel/intern/mesh_tessellate.c
+++ /dev/null
@@ -1,342 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later
- * Copyright 2001-2002 NaN Holding BV. All rights reserved. */
-
-/** \file
- * \ingroup bke
- *
- * This file contains code for polygon tessellation
- * (creating triangles from polygons).
- *
- * \see bmesh_mesh_tessellate.c for the #BMesh equivalent of this file.
- */
-
-#include 
-
-#include "MEM_guardedalloc.h"
-
-#include "DNA_mesh_types.h"
-#include "DNA_meshdata_types.h"
-
-#include "BLI_math.h"
-#include "BLI_memarena.h"
-#include "BLI_polyfill_2d.h"
-#include "BLI_task.h"
-#include "BLI_utildefines.h"
-
-#include "BKE_customdata.h"
-#include "BKE_mesh.h" /* Own include. */
-
-#include "BLI_strict_flags.h"
-
-/** Compared against total loops. */
-#define MESH_FACE_TESSELLATE_THREADED_LIMIT 4096
-
-/* -------------------------------------------------------------------- */
-/** \name Loop Tessellation
- *
- * Fill in #MLoopTri data-structure.
- * \{ */
-
-/**
- * \param face_normal: This will be optimized out as a constant.
- */
-BLI_INLINE void mesh_calc_tessellation_for_face_impl(const MLoop *mloop,
-                                                     const MPoly *mpoly,
-                                                     const MVert *mvert,
-                                                     uint poly_index,
-                                                     MLoopTri *mlt,
-                                                     MemArena **pf_arena_p,
-                                                     const bool face_normal,
-                                                     const float normal_precalc[3])
-{
-  const uint mp_loopstart = (uint)mpoly[poly_index].loopstart;
-  const uint mp_totloop = (uint)mpoly[poly_index].totloop;
-
-#define ML_TO_MLT(i1, i2, i3) \
-  { \
-    ARRAY_SET_ITEMS(mlt->tri, mp_loopstart + i1, mp_loopstart + i2, mp_loopstart + i3); \
-    mlt->poly = poly_index; \
-  } \
-  ((void)0)
-
-  switch (mp_totloop) {
-    case 3: {
-      ML_TO_MLT(0, 1, 2);
-      break;
-    }
-    case 4: {
-      ML_TO_MLT(0, 1, 2);
-      MLoopTri *mlt_a = mlt++;
-      ML_TO_MLT(0, 2, 3);
-      MLoopTri *mlt_b = mlt;
-
-      if (UNLIKELY(face_normal ? is_quad_flip_v3_first_third_fast_with_normal(
-                                     /* Simpler calculation (using the normal). */
-                                     mvert[mloop[mlt_a->tri[0]].v].co,
-                                     mvert[mloop[mlt_a->tri[1]].v].co,
-                                     mvert[mloop[mlt_a->tri[2]].v].co,
-                                     mvert[mloop[mlt_b->tri[2]].v].co,
-                                     normal_precalc) :
-                                 is_quad_flip_v3_first_third_fast(
-                                     /* Expensive calculation (no normal). */
-                                     mvert[mloop[mlt_a->tri[0]].v].co,
-                                     mvert[mloop[mlt_a->tri[1]].v].co,
-                                     mvert[mloop[mlt_a->tri[2]].v].co,
-                                     mvert[mloop[mlt_b->tri[2]].v].co))) {
-        /* Flip out of degenerate 0-2 state. */
-        mlt_a->tri[2] = mlt_b->tri[2];
-        mlt_b->tri[0] = mlt_a->tri[1];
-      }
-      break;
-    }
-    default: {
-      const MLoop *ml;
-      float axis_mat[3][3];
-
-      /* Calculate `axis_mat` to project verts to 2D. */
-      if (face_normal == false) {
-        float normal[3];
-        const float *co_curr, *co_prev;
-
-        zero_v3(normal);
-
-        /* Calc normal, flipped: to get a positive 2D cross product. */
-        ml = mloop + mp_loopstart;
-        co_prev = mvert[ml[mp_totloop - 1].v].co;
-        for (uint j = 0; j < mp_totloop; j++, ml++) {
-          co_curr = mvert[ml->v].co;
-          add_newell_cross_v3_v3v3(normal, co_prev, co_curr);
-          co_prev = co_curr;
-        }
-        if (UNLIKELY(normalize_v3(normal) == 0.0f)) {
-          normal[2] = 1.0f;
-        }
-        axis_dominant_v3_to_m3_negate(axis_mat, normal);
-      }
-      else {
-        axis_dominant_v3_to_m3_negate(axis_mat, normal_precalc);
-      }
-
-      const uint totfilltri = mp_totloop - 2;
-
-      MemArena *pf_arena = *pf_arena_p;
-      if (UNLIKELY(pf_arena == NULL)) {
-        pf_arena = *pf_arena_p = BLI_memarena_new(BLI_MEMARENA_STD_BUFSIZE, __func__);
-      }
-
-      uint(*tris)[3] = tris = BLI_memarena_alloc(pf_arena, sizeof(*tris) * (size_t)totfilltri);
-      float(*projverts)[2] = projverts = BLI_memarena_alloc(
-          pf_arena, sizeof(*projverts) * (size_t)mp_totloop);
-
-      ml = mloop + mp_loopstart;
-      for (uint j = 0; j < mp_totloop; j++, ml++) {
-        mul_v2_m3v3(projverts[j], axis_mat, mvert[ml->v].co);
-      }
-
-      BLI_polyfill_calc_arena(projverts, mp_totloop, 1, tris, pf_arena);
-
-      /* Apply fill. */
-      for (uint j = 0; j < totfilltri; j++, mlt++) {
-        const uint *tri = tris[j];
-        ML_TO_MLT(tri[0], tri[1], tri[2]);
-      }
-
-      BLI_memarena_clear(pf_arena);
-
-      break;
-    }
-  }
-#undef ML_TO_MLT
-}
-
-static void mesh_calc_tessellation_for_face(const MLoop *mloop,
-                                            const MPoly *mpoly,
-                                            const MVert *mvert,
-                                            uint poly_index,
-                                            MLoopTri *mlt,
-                                            MemArena **pf_arena_p)
-{
-  mesh_calc_tessellation_for_face_impl(
-      mloop, mpoly, mvert, poly_index, mlt, pf_arena_p, false, NULL);
-}
-
-static void mesh_calc_tessellation_for_face_with_normal(const MLoop *mloop,
-                                                        const MPoly *mpoly,
-                                                        const MVert *mvert,
-                                                        uint poly_index,
-                                                        MLoopTri *mlt,
-                                                        MemArena **pf_arena_p,
-                                                        const float normal_precalc[3])
-{
-  mesh_calc_tessellation_for_face_impl(
-      mloop, mpoly, mvert, poly_index, mlt, pf_arena_p, true, normal_precalc);
-}
-
-static void mesh_recalc_looptri__single_threaded(const MLoop *mloop,
-                                                 const MPoly *mpoly,
-                                                 const MVert *mvert,
-                                                 int totloop,
-                                                 int totpoly,
-                                                 MLoopTri *mlooptri,
-                                                 const float (*poly_normals)[3])
-{
-  MemArena *pf_arena = NULL;
-  const MPoly *mp = mpoly;
-  uint tri_index = 0;
-
-  if (poly_normals != NULL) {
-    for (uint poly_index = 0; poly_index < (uint)totpoly; poly_index++, mp++) {
-      mesh_calc_tessellation_for_face_with_normal(mloop,
-                                                  mpoly,
-                                                  mvert,
-                                                  poly_index,
-                                                  &mlooptri[tri_index],
-                                                  &pf_arena,
-                                                  poly_normals[poly_index]);
-      tri_index += (uint)(mp->totloop - 2);
-    }
-  }
-  else {
-    for (uint poly_index = 0; poly_index < (uint)totpoly; poly_index++, mp++) {
-      mesh_calc_tessellation_for_face(
-          mloop, mpoly, mvert, poly_index, &mlooptri[tri_index], &pf_arena);
-      tri_index += (uint)(mp->totloop - 2);
-    }
-  }
-
-  if (pf_arena) {
-    BLI_memarena_free(pf_arena);
-    pf_arena = NULL;
-  }
-  BLI_assert(tri_index == (uint)poly_to_tri_count(totpoly, totloop));
-  UNUSED_VARS_NDEBUG(totloop);
-}
-
-struct TessellationUserData {
-  const MLoop *mloop;
-  const MPoly *mpoly;
-  const MVert *mvert;
-
-  /** Output array. */
-  MLoopTri *mlooptri;
-
-  /** Optional pre-calculated polygon normals array. */
-  const float (*poly_normals)[3];
-};
-
-struct TessellationUserTLS {
-  MemArena *pf_arena;
-};
-
-static void mesh_calc_tessellation_for_face_fn(void *__restrict userdata,
-                                               const int index,
-                                               const TaskParallelTLS *__restrict tls)
-{
-  const struct TessellationUserData *data = userdata;
-  struct TessellationUserTLS *tls_data = tls->userdata_chunk;
-  const int tri_index = poly_to_tri_count(index, data->mpoly[index].loopstart);
-  mesh_calc_tessellation_for_face_impl(data->mloop,
-                                       data->mpoly,
-                                       data->mvert,
-                                       (uint)index,
-                                       &data->mlooptri[tri_index],
-                                       &tls_data->pf_arena,
-                                       false,
-                                       NULL);
-}
-
-static void mesh_calc_tessellation_for_face_with_normal_fn(void *__restrict userdata,
-                                                           const int index,
-                                                           const TaskParallelTLS *__restrict tls)
-{
-  const struct TessellationUserData *data = userdata;
-  struct TessellationUserTLS *tls_data = tls->userdata_chunk;
-  const int tri_index = poly_to_tri_count(index, data->mpoly[index].loopstart);
-  mesh_calc_tessellation_for_face_impl(data->mloop,
-                                       data->mpoly,
-                                       data->mvert,
-                                       (uint)index,
-                                       &data->mlooptri[tri_index],
-                                       &tls_data->pf_arena,
-                                       true,
-                                       data->poly_normals[index]);
-}
-
-static void mesh_calc_tessellation_for_face_free_fn(const void *__restrict UNUSED(userdata),
-                                                    void *__restrict tls_v)
-{
-  struct TessellationUserTLS *tls_data = tls_v;
-  if (tls_data->pf_arena) {
-    BLI_memarena_free(tls_data->pf_arena);
-  }
-}
-
-static void mesh_recalc_looptri__multi_threaded(const MLoop *mloop,
-                                                const MPoly *mpoly,
-                                                const MVert *mvert,
-                                                int UNUSED(totloop),
-                                                int totpoly,
-                                                MLoopTri *mlooptri,
-                                                const float (*poly_normals)[3])
-{
-  struct TessellationUserTLS tls_data_dummy = {NULL};
-
-  struct TessellationUserData data = {
-      .mloop = mloop,
-      .mpoly = mpoly,
-      .mvert = mvert,
-      .mlooptri = mlooptri,
-      .poly_normals = poly_normals,
-  };
-
-  TaskParallelSettings settings;
-  BLI_parallel_range_settings_defaults(&settings);
-
-  settings.userdata_chunk = &tls_data_dummy;
-  settings.userdata_chunk_size = sizeof(tls_data_dummy);
-
-  settings.func_free = mesh_calc_tessellation_for_face_free_fn;
-
-  BLI_task_parallel_range(0,
-                          totpoly,
-                          &data,
-                          poly_normals ? mesh_calc_tessellation_for_face_with_normal_fn :
-                                         mesh_calc_tessellation_for_face_fn,
-                          &settings);
-}
-
-void BKE_mesh_recalc_looptri(const MLoop *mloop,
-                             const MPoly *mpoly,
-                             const MVert *mvert,
-                             int totloop,
-                             int totpoly,
-                             MLoopTri *mlooptri)
-{
-  if (totloop < MESH_FACE_TESSELLATE_THREADED_LIMIT) {
-    mesh_recalc_looptri__single_threaded(mloop, mpoly, mvert, totloop, totpoly, mlooptri, NULL);
-  }
-  else {
-    mesh_recalc_looptri__multi_threaded(mloop, mpoly, mvert, totloop, totpoly, mlooptri, NULL);
-  }
-}
-
-void BKE_mesh_recalc_looptri_with_normals(const MLoop *mloop,
-                                          const MPoly *mpoly,
-                                          const MVert *mvert,
-                                          int totloop,
-                                          int totpoly,
-                                          MLoopTri *mlooptri,
-                                          const float (*poly_normals)[3])
-{
-  BLI_assert(poly_normals != NULL);
-  if (totloop < MESH_FACE_TESSELLATE_THREADED_LIMIT) {
-    mesh_recalc_looptri__single_threaded(
-        mloop, mpoly, mvert, totloop, totpoly, mlooptri, poly_normals);
-  }
-  else {
-    mesh_recalc_looptri__multi_threaded(
-        mloop, mpoly, mvert, totloop, totpoly, mlooptri, poly_normals);
-  }
-}
-
-/** \} */
diff --git a/source/blender/blenkernel/intern/mesh_tessellate.cc b/source/blender/blenkernel/intern/mesh_tessellate.cc
new file mode 100644
index 00000000000..de4c60b28db
--- /dev/null
+++ b/source/blender/blenkernel/intern/mesh_tessellate.cc
@@ -0,0 +1,343 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright 2001-2002 NaN Holding BV. All rights reserved. */
+
+/** \file
+ * \ingroup bke
+ *
+ * This file contains code for polygon tessellation
+ * (creating triangles from polygons).
+ *
+ * \see bmesh_mesh_tessellate.c for the #BMesh equivalent of this file.
+ */
+
+#include 
+
+#include "MEM_guardedalloc.h"
+
+#include "DNA_mesh_types.h"
+#include "DNA_meshdata_types.h"
+
+#include "BLI_math.h"
+#include "BLI_memarena.h"
+#include "BLI_polyfill_2d.h"
+#include "BLI_task.h"
+#include "BLI_utildefines.h"
+
+#include "BKE_customdata.h"
+#include "BKE_mesh.h" /* Own include. */
+
+#include "BLI_strict_flags.h"
+
+/** Compared against total loops. */
+#define MESH_FACE_TESSELLATE_THREADED_LIMIT 4096
+
+/* -------------------------------------------------------------------- */
+/** \name Loop Tessellation
+ *
+ * Fill in #MLoopTri data-structure.
+ * \{ */
+
+/**
+ * \param face_normal: This will be optimized out as a constant.
+ */
+BLI_INLINE void mesh_calc_tessellation_for_face_impl(const MLoop *mloop,
+                                                     const MPoly *mpoly,
+                                                     const MVert *mvert,
+                                                     uint poly_index,
+                                                     MLoopTri *mlt,
+                                                     MemArena **pf_arena_p,
+                                                     const bool face_normal,
+                                                     const float normal_precalc[3])
+{
+  const uint mp_loopstart = (uint)mpoly[poly_index].loopstart;
+  const uint mp_totloop = (uint)mpoly[poly_index].totloop;
+
+#define ML_TO_MLT(i1, i2, i3) \
+  { \
+    ARRAY_SET_ITEMS(mlt->tri, mp_loopstart + i1, mp_loopstart + i2, mp_loopstart + i3); \
+    mlt->poly = poly_index; \
+  } \
+  ((void)0)
+
+  switch (mp_totloop) {
+    case 3: {
+      ML_TO_MLT(0, 1, 2);
+      break;
+    }
+    case 4: {
+      ML_TO_MLT(0, 1, 2);
+      MLoopTri *mlt_a = mlt++;
+      ML_TO_MLT(0, 2, 3);
+      MLoopTri *mlt_b = mlt;
+
+      if (UNLIKELY(face_normal ? is_quad_flip_v3_first_third_fast_with_normal(
+                                     /* Simpler calculation (using the normal). */
+                                     mvert[mloop[mlt_a->tri[0]].v].co,
+                                     mvert[mloop[mlt_a->tri[1]].v].co,
+                                     mvert[mloop[mlt_a->tri[2]].v].co,
+                                     mvert[mloop[mlt_b->tri[2]].v].co,
+                                     normal_precalc) :
+                                 is_quad_flip_v3_first_third_fast(
+                                     /* Expensive calculation (no normal). */
+                                     mvert[mloop[mlt_a->tri[0]].v].co,
+                                     mvert[mloop[mlt_a->tri[1]].v].co,
+                                     mvert[mloop[mlt_a->tri[2]].v].co,
+                                     mvert[mloop[mlt_b->tri[2]].v].co))) {
+        /* Flip out of degenerate 0-2 state. */
+        mlt_a->tri[2] = mlt_b->tri[2];
+        mlt_b->tri[0] = mlt_a->tri[1];
+      }
+      break;
+    }
+    default: {
+      const MLoop *ml;
+      float axis_mat[3][3];
+
+      /* Calculate `axis_mat` to project verts to 2D. */
+      if (face_normal == false) {
+        float normal[3];
+        const float *co_curr, *co_prev;
+
+        zero_v3(normal);
+
+        /* Calc normal, flipped: to get a positive 2D cross product. */
+        ml = mloop + mp_loopstart;
+        co_prev = mvert[ml[mp_totloop - 1].v].co;
+        for (uint j = 0; j < mp_totloop; j++, ml++) {
+          co_curr = mvert[ml->v].co;
+          add_newell_cross_v3_v3v3(normal, co_prev, co_curr);
+          co_prev = co_curr;
+        }
+        if (UNLIKELY(normalize_v3(normal) == 0.0f)) {
+          normal[2] = 1.0f;
+        }
+        axis_dominant_v3_to_m3_negate(axis_mat, normal);
+      }
+      else {
+        axis_dominant_v3_to_m3_negate(axis_mat, normal_precalc);
+      }
+
+      const uint totfilltri = mp_totloop - 2;
+
+      MemArena *pf_arena = *pf_arena_p;
+      if (UNLIKELY(pf_arena == nullptr)) {
+        pf_arena = *pf_arena_p = BLI_memarena_new(BLI_MEMARENA_STD_BUFSIZE, __func__);
+      }
+
+      uint(*tris)[3] = static_cast(
+          BLI_memarena_alloc(pf_arena, sizeof(*tris) * (size_t)totfilltri));
+      float(*projverts)[2] = static_cast(
+          BLI_memarena_alloc(pf_arena, sizeof(*projverts) * (size_t)mp_totloop));
+
+      ml = mloop + mp_loopstart;
+      for (uint j = 0; j < mp_totloop; j++, ml++) {
+        mul_v2_m3v3(projverts[j], axis_mat, mvert[ml->v].co);
+      }
+
+      BLI_polyfill_calc_arena(projverts, mp_totloop, 1, tris, pf_arena);
+
+      /* Apply fill. */
+      for (uint j = 0; j < totfilltri; j++, mlt++) {
+        const uint *tri = tris[j];
+        ML_TO_MLT(tri[0], tri[1], tri[2]);
+      }
+
+      BLI_memarena_clear(pf_arena);
+
+      break;
+    }
+  }
+#undef ML_TO_MLT
+}
+
+static void mesh_calc_tessellation_for_face(const MLoop *mloop,
+                                            const MPoly *mpoly,
+                                            const MVert *mvert,
+                                            uint poly_index,
+                                            MLoopTri *mlt,
+                                            MemArena **pf_arena_p)
+{
+  mesh_calc_tessellation_for_face_impl(
+      mloop, mpoly, mvert, poly_index, mlt, pf_arena_p, false, nullptr);
+}
+
+static void mesh_calc_tessellation_for_face_with_normal(const MLoop *mloop,
+                                                        const MPoly *mpoly,
+                                                        const MVert *mvert,
+                                                        uint poly_index,
+                                                        MLoopTri *mlt,
+                                                        MemArena **pf_arena_p,
+                                                        const float normal_precalc[3])
+{
+  mesh_calc_tessellation_for_face_impl(
+      mloop, mpoly, mvert, poly_index, mlt, pf_arena_p, true, normal_precalc);
+}
+
+static void mesh_recalc_looptri__single_threaded(const MLoop *mloop,
+                                                 const MPoly *mpoly,
+                                                 const MVert *mvert,
+                                                 int totloop,
+                                                 int totpoly,
+                                                 MLoopTri *mlooptri,
+                                                 const float (*poly_normals)[3])
+{
+  MemArena *pf_arena = nullptr;
+  const MPoly *mp = mpoly;
+  uint tri_index = 0;
+
+  if (poly_normals != nullptr) {
+    for (uint poly_index = 0; poly_index < (uint)totpoly; poly_index++, mp++) {
+      mesh_calc_tessellation_for_face_with_normal(mloop,
+                                                  mpoly,
+                                                  mvert,
+                                                  poly_index,
+                                                  &mlooptri[tri_index],
+                                                  &pf_arena,
+                                                  poly_normals[poly_index]);
+      tri_index += (uint)(mp->totloop - 2);
+    }
+  }
+  else {
+    for (uint poly_index = 0; poly_index < (uint)totpoly; poly_index++, mp++) {
+      mesh_calc_tessellation_for_face(
+          mloop, mpoly, mvert, poly_index, &mlooptri[tri_index], &pf_arena);
+      tri_index += (uint)(mp->totloop - 2);
+    }
+  }
+
+  if (pf_arena) {
+    BLI_memarena_free(pf_arena);
+    pf_arena = nullptr;
+  }
+  BLI_assert(tri_index == (uint)poly_to_tri_count(totpoly, totloop));
+  UNUSED_VARS_NDEBUG(totloop);
+}
+
+struct TessellationUserData {
+  const MLoop *mloop;
+  const MPoly *mpoly;
+  const MVert *mvert;
+
+  /** Output array. */
+  MLoopTri *mlooptri;
+
+  /** Optional pre-calculated polygon normals array. */
+  const float (*poly_normals)[3];
+};
+
+struct TessellationUserTLS {
+  MemArena *pf_arena;
+};
+
+static void mesh_calc_tessellation_for_face_fn(void *__restrict userdata,
+                                               const int index,
+                                               const TaskParallelTLS *__restrict tls)
+{
+  const TessellationUserData *data = static_cast(userdata);
+  TessellationUserTLS *tls_data = static_cast(tls->userdata_chunk);
+  const int tri_index = poly_to_tri_count(index, data->mpoly[index].loopstart);
+  mesh_calc_tessellation_for_face_impl(data->mloop,
+                                       data->mpoly,
+                                       data->mvert,
+                                       (uint)index,
+                                       &data->mlooptri[tri_index],
+                                       &tls_data->pf_arena,
+                                       false,
+                                       nullptr);
+}
+
+static void mesh_calc_tessellation_for_face_with_normal_fn(void *__restrict userdata,
+                                                           const int index,
+                                                           const TaskParallelTLS *__restrict tls)
+{
+  const TessellationUserData *data = static_cast(userdata);
+  TessellationUserTLS *tls_data = static_cast(tls->userdata_chunk);
+  const int tri_index = poly_to_tri_count(index, data->mpoly[index].loopstart);
+  mesh_calc_tessellation_for_face_impl(data->mloop,
+                                       data->mpoly,
+                                       data->mvert,
+                                       (uint)index,
+                                       &data->mlooptri[tri_index],
+                                       &tls_data->pf_arena,
+                                       true,
+                                       data->poly_normals[index]);
+}
+
+static void mesh_calc_tessellation_for_face_free_fn(const void *__restrict UNUSED(userdata),
+                                                    void *__restrict tls_v)
+{
+  TessellationUserTLS *tls_data = static_cast(tls_v);
+  if (tls_data->pf_arena) {
+    BLI_memarena_free(tls_data->pf_arena);
+  }
+}
+
+static void mesh_recalc_looptri__multi_threaded(const MLoop *mloop,
+                                                const MPoly *mpoly,
+                                                const MVert *mvert,
+                                                int UNUSED(totloop),
+                                                int totpoly,
+                                                MLoopTri *mlooptri,
+                                                const float (*poly_normals)[3])
+{
+  struct TessellationUserTLS tls_data_dummy = {nullptr};
+
+  struct TessellationUserData data {
+  };
+  data.mloop = mloop;
+  data.mpoly = mpoly;
+  data.mvert = mvert;
+  data.mlooptri = mlooptri;
+  data.poly_normals = poly_normals;
+
+  TaskParallelSettings settings;
+  BLI_parallel_range_settings_defaults(&settings);
+
+  settings.userdata_chunk = &tls_data_dummy;
+  settings.userdata_chunk_size = sizeof(tls_data_dummy);
+
+  settings.func_free = mesh_calc_tessellation_for_face_free_fn;
+
+  BLI_task_parallel_range(0,
+                          totpoly,
+                          &data,
+                          poly_normals ? mesh_calc_tessellation_for_face_with_normal_fn :
+                                         mesh_calc_tessellation_for_face_fn,
+                          &settings);
+}
+
+void BKE_mesh_recalc_looptri(const MLoop *mloop,
+                             const MPoly *mpoly,
+                             const MVert *mvert,
+                             int totloop,
+                             int totpoly,
+                             MLoopTri *mlooptri)
+{
+  if (totloop < MESH_FACE_TESSELLATE_THREADED_LIMIT) {
+    mesh_recalc_looptri__single_threaded(mloop, mpoly, mvert, totloop, totpoly, mlooptri, nullptr);
+  }
+  else {
+    mesh_recalc_looptri__multi_threaded(mloop, mpoly, mvert, totloop, totpoly, mlooptri, nullptr);
+  }
+}
+
+void BKE_mesh_recalc_looptri_with_normals(const MLoop *mloop,
+                                          const MPoly *mpoly,
+                                          const MVert *mvert,
+                                          int totloop,
+                                          int totpoly,
+                                          MLoopTri *mlooptri,
+                                          const float (*poly_normals)[3])
+{
+  BLI_assert(poly_normals != nullptr);
+  if (totloop < MESH_FACE_TESSELLATE_THREADED_LIMIT) {
+    mesh_recalc_looptri__single_threaded(
+        mloop, mpoly, mvert, totloop, totpoly, mlooptri, poly_normals);
+  }
+  else {
+    mesh_recalc_looptri__multi_threaded(
+        mloop, mpoly, mvert, totloop, totpoly, mlooptri, poly_normals);
+  }
+}
+
+/** \} */
diff --git a/source/blender/blenkernel/intern/mesh_validate.cc b/source/blender/blenkernel/intern/mesh_validate.cc
index 9b2697ecc84..47de7245ccc 100644
--- a/source/blender/blenkernel/intern/mesh_validate.cc
+++ b/source/blender/blenkernel/intern/mesh_validate.cc
@@ -24,6 +24,7 @@
 #include "BLI_math_vector.h"
 #include "BLI_utildefines.h"
 
+#include "BKE_attribute.hh"
 #include "BKE_customdata.h"
 #include "BKE_deform.h"
 #include "BKE_mesh.h"
@@ -32,6 +33,9 @@
 
 #include "MEM_guardedalloc.h"
 
+using blender::MutableSpan;
+using blender::Span;
+
 /* loop v/e are unsigned, so using max uint_32 value as invalid marker... */
 #define INVALID_LOOP_EDGE_MARKER 4294967295u
 
@@ -238,6 +242,10 @@ bool BKE_mesh_validate_arrays(Mesh *mesh,
   } \
   (void)0
 
+  blender::bke::AttributeWriter material_indices =
+      mesh->attributes_for_write().lookup_for_write("material_index");
+  blender::MutableVArraySpan material_indices_span(material_indices.varray);
+
   MVert *mv = mverts;
   MEdge *me;
   MLoop *ml;
@@ -559,10 +567,10 @@ bool BKE_mesh_validate_arrays(Mesh *mesh,
       /* Material index, isolated from other tests here. While large indices are clamped,
        * negative indices aren't supported by drawing, exporters etc.
        * To check the indices are in range, use #BKE_mesh_validate_material_indices */
-      if (mp->mat_nr < 0) {
-        PRINT_ERR("\tPoly %u has invalid material (%d)", sp->index, mp->mat_nr);
+      if (material_indices && material_indices_span[i] < 0) {
+        PRINT_ERR("\tPoly %u has invalid material (%d)", sp->index, material_indices_span[i]);
         if (do_fixes) {
-          mp->mat_nr = 0;
+          material_indices_span[i] = 0;
         }
       }
 
@@ -916,6 +924,9 @@ bool BKE_mesh_validate_arrays(Mesh *mesh,
     }
   }
 
+  material_indices_span.save();
+  material_indices.finish();
+
   PRINT_MSG("%s: finished\n\n", __func__);
 
   *r_changed = (fix_flag.as_flag || free_flag.as_flag || recalc_flag.as_flag);
@@ -1001,10 +1012,6 @@ bool BKE_mesh_validate_all_customdata(CustomData *vdata,
   CustomData_MeshMasks mask = {0};
   if (check_meshmask) {
     mask = CD_MASK_MESH;
-    /* Normal data isn't in the mask since it is derived data,
-     * but it is valid and should not be removed. */
-    mask.vmask |= CD_MASK_NORMAL;
-    mask.pmask |= CD_MASK_NORMAL;
   }
 
   is_valid &= mesh_validate_customdata(
@@ -1017,7 +1024,6 @@ bool BKE_mesh_validate_all_customdata(CustomData *vdata,
       pdata, mask.pmask, totpoly, do_verbose, do_fixes, &is_change_p);
 
   const int tot_uvloop = CustomData_number_of_layers(ldata, CD_MLOOPUV);
-  const int tot_vcolloop = CustomData_number_of_layers(ldata, CD_PROP_BYTE_COLOR);
   if (tot_uvloop > MAX_MTFACE) {
     PRINT_ERR(
         "\tMore UV layers than %d allowed, %d last ones won't be available for render, shaders, "
@@ -1025,13 +1031,6 @@ bool BKE_mesh_validate_all_customdata(CustomData *vdata,
         MAX_MTFACE,
         tot_uvloop - MAX_MTFACE);
   }
-  if (tot_vcolloop > MAX_MCOL) {
-    PRINT_ERR(
-        "\tMore VCol layers than %d allowed, %d last ones won't be available for render, shaders, "
-        "etc.\n",
-        MAX_MCOL,
-        tot_vcolloop - MAX_MCOL);
-  }
 
   /* check indices of clone/stencil */
   if (do_fixes && CustomData_get_clone_layer(ldata, CD_MLOOPUV) >= tot_uvloop) {
@@ -1068,19 +1067,23 @@ bool BKE_mesh_validate(Mesh *me, const bool do_verbose, const bool cddata_check_
                                    do_verbose,
                                    true,
                                    &changed);
+  MutableSpan verts = me->verts_for_write();
+  MutableSpan edges = me->edges_for_write();
+  MutableSpan polys = me->polys_for_write();
+  MutableSpan loops = me->loops_for_write();
 
   BKE_mesh_validate_arrays(me,
-                           me->mvert,
-                           me->totvert,
-                           me->medge,
-                           me->totedge,
-                           me->mface,
+                           verts.data(),
+                           verts.size(),
+                           edges.data(),
+                           edges.size(),
+                           (MFace *)CustomData_get_layer(&me->fdata, CD_MFACE),
                            me->totface,
-                           me->mloop,
-                           me->totloop,
-                           me->mpoly,
-                           me->totpoly,
-                           me->dvert,
+                           loops.data(),
+                           loops.size(),
+                           polys.data(),
+                           polys.size(),
+                           me->deform_verts_for_write().data(),
                            do_verbose,
                            true,
                            &changed);
@@ -1117,18 +1120,23 @@ bool BKE_mesh_is_valid(Mesh *me)
       do_fixes,
       &changed);
 
+  MutableSpan verts = me->verts_for_write();
+  MutableSpan edges = me->edges_for_write();
+  MutableSpan polys = me->polys_for_write();
+  MutableSpan loops = me->loops_for_write();
+
   is_valid &= BKE_mesh_validate_arrays(me,
-                                       me->mvert,
-                                       me->totvert,
-                                       me->medge,
-                                       me->totedge,
-                                       me->mface,
+                                       verts.data(),
+                                       verts.size(),
+                                       edges.data(),
+                                       edges.size(),
+                                       (MFace *)CustomData_get_layer(&me->fdata, CD_MFACE),
                                        me->totface,
-                                       me->mloop,
-                                       me->totloop,
-                                       me->mpoly,
-                                       me->totpoly,
-                                       me->dvert,
+                                       loops.data(),
+                                       loops.size(),
+                                       polys.data(),
+                                       polys.size(),
+                                       me->deform_verts_for_write().data(),
                                        do_verbose,
                                        do_fixes,
                                        &changed);
@@ -1140,19 +1148,20 @@ bool BKE_mesh_is_valid(Mesh *me)
 
 bool BKE_mesh_validate_material_indices(Mesh *me)
 {
-  /* Cast to unsigned to catch negative indices too. */
-  const uint16_t mat_nr_max = max_ii(0, me->totcol - 1);
-  MPoly *mp;
-  const int totpoly = me->totpoly;
-  int i;
+  const int mat_nr_max = max_ii(0, me->totcol - 1);
   bool is_valid = true;
 
-  for (mp = me->mpoly, i = 0; i < totpoly; i++, mp++) {
-    if ((uint16_t)mp->mat_nr > mat_nr_max) {
-      mp->mat_nr = 0;
+  blender::bke::AttributeWriter material_indices =
+      me->attributes_for_write().lookup_for_write("material_index");
+  blender::MutableVArraySpan material_indices_span(material_indices.varray);
+  for (const int i : material_indices_span.index_range()) {
+    if (material_indices_span[i] < 0 || material_indices_span[i] > mat_nr_max) {
+      material_indices_span[i] = 0;
       is_valid = false;
     }
   }
+  material_indices_span.save();
+  material_indices.finish();
 
   if (!is_valid) {
     DEG_id_tag_update(&me->id, ID_RECALC_GEOMETRY_ALL_MODES);
@@ -1173,11 +1182,12 @@ void BKE_mesh_strip_loose_faces(Mesh *me)
   /* NOTE: We need to keep this for edge creation (for now?), and some old `readfile.c` code. */
   MFace *f;
   int a, b;
+  MFace *mfaces = (MFace *)CustomData_get_layer(&me->fdata, CD_MFACE);
 
-  for (a = b = 0, f = me->mface; a < me->totface; a++, f++) {
+  for (a = b = 0, f = mfaces; a < me->totface; a++, f++) {
     if (f->v3) {
       if (a != b) {
-        memcpy(&me->mface[b], f, sizeof(me->mface[b]));
+        memcpy(&mfaces[b], f, sizeof(mfaces[b]));
         CustomData_copy_data(&me->fdata, &me->fdata, a, b, 1);
       }
       b++;
@@ -1191,13 +1201,16 @@ void BKE_mesh_strip_loose_faces(Mesh *me)
 
 void BKE_mesh_strip_loose_polysloops(Mesh *me)
 {
+  MutableSpan polys = me->polys_for_write();
+  MutableSpan loops = me->loops_for_write();
+
   MPoly *p;
   MLoop *l;
   int a, b;
   /* New loops idx! */
   int *new_idx = (int *)MEM_mallocN(sizeof(int) * me->totloop, __func__);
 
-  for (a = b = 0, p = me->mpoly; a < me->totpoly; a++, p++) {
+  for (a = b = 0, p = polys.data(); a < me->totpoly; a++, p++) {
     bool invalid = false;
     int i = p->loopstart;
     int stop = i + p->totloop;
@@ -1206,7 +1219,7 @@ void BKE_mesh_strip_loose_polysloops(Mesh *me)
       invalid = true;
     }
     else {
-      l = &me->mloop[i];
+      l = &loops[i];
       i = stop - i;
       /* If one of the poly's loops is invalid, the whole poly is invalid! */
       for (; i--; l++) {
@@ -1219,7 +1232,7 @@ void BKE_mesh_strip_loose_polysloops(Mesh *me)
 
     if (p->totloop >= 3 && !invalid) {
       if (a != b) {
-        memcpy(&me->mpoly[b], p, sizeof(me->mpoly[b]));
+        memcpy(&polys[b], p, sizeof(polys[b]));
         CustomData_copy_data(&me->pdata, &me->pdata, a, b, 1);
       }
       b++;
@@ -1231,10 +1244,10 @@ void BKE_mesh_strip_loose_polysloops(Mesh *me)
   }
 
   /* And now, get rid of invalid loops. */
-  for (a = b = 0, l = me->mloop; a < me->totloop; a++, l++) {
+  for (a = b = 0, l = loops.data(); a < me->totloop; a++, l++) {
     if (l->e != INVALID_LOOP_EDGE_MARKER) {
       if (a != b) {
-        memcpy(&me->mloop[b], l, sizeof(me->mloop[b]));
+        memcpy(&loops[b], l, sizeof(loops[b]));
         CustomData_copy_data(&me->ldata, &me->ldata, a, b, 1);
       }
       new_idx[a] = b;
@@ -1253,8 +1266,8 @@ void BKE_mesh_strip_loose_polysloops(Mesh *me)
 
   /* And now, update polys' start loop index. */
   /* NOTE: At this point, there should never be any poly using a striped loop! */
-  for (a = 0, p = me->mpoly; a < me->totpoly; a++, p++) {
-    p->loopstart = new_idx[p->loopstart];
+  for (const int i : polys.index_range()) {
+    polys[i].loopstart = new_idx[polys[i].loopstart];
   }
 
   MEM_freeN(new_idx);
@@ -1263,14 +1276,14 @@ void BKE_mesh_strip_loose_polysloops(Mesh *me)
 void BKE_mesh_strip_loose_edges(Mesh *me)
 {
   MEdge *e;
-  MLoop *l;
   int a, b;
   uint *new_idx = (uint *)MEM_mallocN(sizeof(int) * me->totedge, __func__);
+  MutableSpan edges = me->edges_for_write();
 
-  for (a = b = 0, e = me->medge; a < me->totedge; a++, e++) {
+  for (a = b = 0, e = edges.data(); a < me->totedge; a++, e++) {
     if (e->v1 != e->v2) {
       if (a != b) {
-        memcpy(&me->medge[b], e, sizeof(me->medge[b]));
+        memcpy(&edges[b], e, sizeof(edges[b]));
         CustomData_copy_data(&me->edata, &me->edata, a, b, 1);
       }
       new_idx[a] = b;
@@ -1288,8 +1301,9 @@ void BKE_mesh_strip_loose_edges(Mesh *me)
   /* And now, update loops' edge indices. */
   /* XXX We hope no loop was pointing to a striped edge!
    *     Else, its e will be set to INVALID_LOOP_EDGE_MARKER :/ */
-  for (a = 0, l = me->mloop; a < me->totloop; a++, l++) {
-    l->e = new_idx[l->e];
+  MutableSpan loops = me->loops_for_write();
+  for (MLoop &loop : loops) {
+    loop.e = new_idx[loop.e];
   }
 
   MEM_freeN(new_idx);
@@ -1347,10 +1361,10 @@ static int vergedgesort(const void *v1, const void *v2)
 /* Create edges based on known verts and faces,
  * this function is only used when loading very old blend files */
 
-static void mesh_calc_edges_mdata(MVert *UNUSED(allvert),
-                                  MFace *allface,
+static void mesh_calc_edges_mdata(const MVert *UNUSED(allvert),
+                                  const MFace *allface,
                                   MLoop *allloop,
-                                  MPoly *allpoly,
+                                  const MPoly *allpoly,
                                   int UNUSED(totvert),
                                   int totface,
                                   int UNUSED(totloop),
@@ -1359,8 +1373,8 @@ static void mesh_calc_edges_mdata(MVert *UNUSED(allvert),
                                   MEdge **r_medge,
                                   int *r_totedge)
 {
-  MPoly *mpoly;
-  MFace *mface;
+  const MPoly *mpoly;
+  const MFace *mface;
   MEdge *medge, *med;
   EdgeHash *hash;
   struct EdgeSort *edsort, *ed;
@@ -1483,28 +1497,29 @@ void BKE_mesh_calc_edges_legacy(Mesh *me, const bool use_old)
 {
   MEdge *medge;
   int totedge = 0;
-
-  mesh_calc_edges_mdata(me->mvert,
-                        me->mface,
-                        me->mloop,
-                        me->mpoly,
-                        me->totvert,
+  const Span verts = me->verts();
+  const Span polys = me->polys();
+  MutableSpan loops = me->loops_for_write();
+
+  mesh_calc_edges_mdata(verts.data(),
+                        (MFace *)CustomData_get_layer(&me->fdata, CD_MFACE),
+                        loops.data(),
+                        polys.data(),
+                        verts.size(),
                         me->totface,
-                        me->totloop,
-                        me->totpoly,
+                        loops.size(),
+                        polys.size(),
                         use_old,
                         &medge,
                         &totedge);
 
   if (totedge == 0) {
     /* flag that mesh has edges */
-    me->medge = medge;
     me->totedge = 0;
     return;
   }
 
   medge = (MEdge *)CustomData_add_layer(&me->edata, CD_MEDGE, CD_ASSIGN, medge, totedge);
-  me->medge = medge;
   me->totedge = totedge;
 
   BKE_mesh_strip_loose_faces(me);
@@ -1512,18 +1527,18 @@ void BKE_mesh_calc_edges_legacy(Mesh *me, const bool use_old)
 
 void BKE_mesh_calc_edges_loose(Mesh *mesh)
 {
-  MEdge *med = mesh->medge;
-  for (int i = 0; i < mesh->totedge; i++, med++) {
-    med->flag |= ME_LOOSEEDGE;
+  const Span loops = mesh->loops();
+  MutableSpan edges = mesh->edges_for_write();
+
+  for (const int i : edges.index_range()) {
+    edges[i].flag |= ME_LOOSEEDGE;
   }
-  MLoop *ml = mesh->mloop;
-  for (int i = 0; i < mesh->totloop; i++, ml++) {
-    mesh->medge[ml->e].flag &= ~ME_LOOSEEDGE;
+  for (const int i : loops.index_range()) {
+    edges[loops[i].e].flag &= ~ME_LOOSEEDGE;
   }
-  med = mesh->medge;
-  for (int i = 0; i < mesh->totedge; i++, med++) {
-    if (med->flag & ME_LOOSEEDGE) {
-      med->flag |= ME_EDGEDRAW;
+  for (const int i : edges.index_range()) {
+    if (edges[i].flag & ME_LOOSEEDGE) {
+      edges[i].flag |= ME_EDGEDRAW;
     }
   }
 }
@@ -1532,8 +1547,9 @@ void BKE_mesh_calc_edges_tessface(Mesh *mesh)
 {
   const int numFaces = mesh->totface;
   EdgeSet *eh = BLI_edgeset_new_ex(__func__, BLI_EDGEHASH_SIZE_GUESS_FROM_POLYS(numFaces));
+  MFace *mfaces = (MFace *)CustomData_get_layer(&mesh->fdata, CD_MFACE);
 
-  MFace *mf = mesh->mface;
+  MFace *mf = mfaces;
   for (int i = 0; i < numFaces; i++, mf++) {
     BLI_edgeset_add(eh, mf->v1, mf->v2);
     BLI_edgeset_add(eh, mf->v2, mf->v3);
@@ -1552,8 +1568,8 @@ void BKE_mesh_calc_edges_tessface(Mesh *mesh)
   /* write new edges into a temporary CustomData */
   CustomData edgeData;
   CustomData_reset(&edgeData);
-  CustomData_add_layer(&edgeData, CD_MEDGE, CD_CALLOC, nullptr, numEdges);
-  CustomData_add_layer(&edgeData, CD_ORIGINDEX, CD_CALLOC, nullptr, numEdges);
+  CustomData_add_layer(&edgeData, CD_MEDGE, CD_SET_DEFAULT, nullptr, numEdges);
+  CustomData_add_layer(&edgeData, CD_ORIGINDEX, CD_SET_DEFAULT, nullptr, numEdges);
 
   MEdge *med = (MEdge *)CustomData_get_layer(&edgeData, CD_MEDGE);
   int *index = (int *)CustomData_get_layer(&edgeData, CD_ORIGINDEX);
@@ -1573,8 +1589,6 @@ void BKE_mesh_calc_edges_tessface(Mesh *mesh)
   mesh->edata = edgeData;
   mesh->totedge = numEdges;
 
-  mesh->medge = (MEdge *)CustomData_get_layer(&mesh->edata, CD_MEDGE);
-
   BLI_edgeset_free(eh);
 }
 
diff --git a/source/blender/blenkernel/intern/mesh_wrapper.cc b/source/blender/blenkernel/intern/mesh_wrapper.cc
index 0362e4866e3..101fad2fce8 100644
--- a/source/blender/blenkernel/intern/mesh_wrapper.cc
+++ b/source/blender/blenkernel/intern/mesh_wrapper.cc
@@ -46,6 +46,8 @@
 #include "DEG_depsgraph.h"
 #include "DEG_depsgraph_query.h"
 
+using blender::Span;
+
 Mesh *BKE_mesh_wrapper_from_editmesh_with_coords(BMEditMesh *em,
                                                  const CustomData_MeshMasks *cd_mask_extra,
                                                  const float (*vert_coords)[3],
@@ -61,7 +63,7 @@ Mesh *BKE_mesh_wrapper_from_editmesh_with_coords(BMEditMesh *em,
   }
 
   /* Use edit-mesh directly where possible. */
-  me->runtime.is_original = true;
+  me->runtime.is_original_bmesh = true;
 
   me->edit_mesh = static_cast(MEM_dupallocN(em));
   me->edit_mesh->is_shallow_copy = true;
@@ -103,11 +105,7 @@ void BKE_mesh_wrapper_ensure_mdata(Mesh *me)
 
   /* Must isolate multithreaded tasks while holding a mutex lock. */
   blender::threading::isolate_task([&]() {
-    const eMeshWrapperType geom_type_orig = static_cast(
-        me->runtime.wrapper_type);
-    me->runtime.wrapper_type = ME_WRAPPER_TYPE_MDATA;
-
-    switch (geom_type_orig) {
+    switch (static_cast(me->runtime.wrapper_type)) {
       case ME_WRAPPER_TYPE_MDATA:
       case ME_WRAPPER_TYPE_SUBD: {
         break; /* Quiet warning. */
@@ -132,20 +130,24 @@ void BKE_mesh_wrapper_ensure_mdata(Mesh *me)
          * There is also a performance aspect, where this also assumes that original indices are
          * always needed when converting an edit mesh to a mesh. That might be wrong, but it's not
          * harmful. */
-        BKE_mesh_ensure_default_orig_index_customdata(me);
+        BKE_mesh_ensure_default_orig_index_customdata_no_check(me);
 
         EditMeshData *edit_data = me->runtime.edit_data;
         if (edit_data->vertexCos) {
           BKE_mesh_vert_coords_apply(me, edit_data->vertexCos);
-          me->runtime.is_original = false;
+          me->runtime.is_original_bmesh = false;
         }
         break;
       }
     }
 
     if (me->runtime.wrapper_type_finalize) {
-      BKE_mesh_wrapper_deferred_finalize(me, &me->runtime.cd_mask_extra);
+      BKE_mesh_wrapper_deferred_finalize_mdata(me, &me->runtime.cd_mask_extra);
     }
+
+    /* Keep type assignment last, so that read-only access only uses the mdata code paths after all
+     * the underlying data has been initialized. */
+    me->runtime.wrapper_type = ME_WRAPPER_TYPE_MDATA;
   });
 
   BLI_mutex_unlock(mesh_eval_mutex);
@@ -195,9 +197,9 @@ void BKE_mesh_wrapper_vert_coords_copy(const Mesh *me,
     case ME_WRAPPER_TYPE_MDATA:
     case ME_WRAPPER_TYPE_SUBD: {
       BLI_assert(vert_coords_len <= me->totvert);
-      const MVert *mvert = me->mvert;
+      const Span verts = me->verts();
       for (int i = 0; i < vert_coords_len; i++) {
-        copy_v3_v3(vert_coords[i], mvert[i].co);
+        copy_v3_v3(vert_coords[i], verts[i].co);
       }
       return;
     }
@@ -233,9 +235,9 @@ void BKE_mesh_wrapper_vert_coords_copy_with_mat4(const Mesh *me,
     case ME_WRAPPER_TYPE_MDATA:
     case ME_WRAPPER_TYPE_SUBD: {
       BLI_assert(vert_coords_len == me->totvert);
-      const MVert *mvert = me->mvert;
+      const Span verts = me->verts();
       for (int i = 0; i < vert_coords_len; i++) {
-        mul_v3_m4v3(vert_coords[i], mat, mvert[i].co);
+        mul_v3_m4v3(vert_coords[i], mat, verts[i].co);
       }
       return;
     }
@@ -343,7 +345,7 @@ static Mesh *mesh_wrapper_ensure_subdivision(Mesh *me)
   if (use_clnors) {
     float(*lnors)[3] = static_cast(
         CustomData_get_layer(&subdiv_mesh->ldata, CD_NORMAL));
-    BLI_assert(lnors != NULL);
+    BLI_assert(lnors != nullptr);
     BKE_mesh_set_custom_normals(subdiv_mesh, lnors);
     CustomData_set_layer_flag(&me->ldata, CD_NORMAL, CD_FLAG_TEMPORARY);
     CustomData_set_layer_flag(&subdiv_mesh->ldata, CD_NORMAL, CD_FLAG_TEMPORARY);
diff --git a/source/blender/blenkernel/intern/modifier.c b/source/blender/blenkernel/intern/modifier.c
index 6348d83362e..ba84b27bf31 100644
--- a/source/blender/blenkernel/intern/modifier.c
+++ b/source/blender/blenkernel/intern/modifier.c
@@ -142,7 +142,8 @@ static ModifierData *modifier_allocate_and_init(int type)
   md->type = type;
   md->mode = eModifierMode_Realtime | eModifierMode_Render;
   md->flag = eModifierFlag_OverrideLibrary_Local;
-  md->ui_expand_flag = 1; /* Only open the main panel at the beginning, not the sub-panels. */
+  /* Only open the main panel at the beginning, not the sub-panels. */
+  md->ui_expand_flag = UI_PANEL_DATA_EXPAND_ROOT;
 
   if (mti->flags & eModifierTypeFlag_EnableInEditmode) {
     md->mode |= eModifierMode_Editmode;
@@ -456,6 +457,40 @@ void BKE_modifier_set_error(const Object *ob, ModifierData *md, const char *_for
   CLOG_ERROR(&LOG, "Object: \"%s\", Modifier: \"%s\", %s", ob->id.name + 2, md->name, md->error);
 }
 
+void BKE_modifier_set_warning(const struct Object *ob,
+                              struct ModifierData *md,
+                              const char *_format,
+                              ...)
+{
+  char buffer[512];
+  va_list ap;
+  const char *format = TIP_(_format);
+
+  va_start(ap, _format);
+  vsnprintf(buffer, sizeof(buffer), format, ap);
+  va_end(ap);
+  buffer[sizeof(buffer) - 1] = '\0';
+
+  /* Store the warning in the same field as the error.
+   * It is not expected to have both error and warning and having a single place to store the
+   * message simplifies interface code. */
+
+  if (md->error) {
+    MEM_freeN(md->error);
+  }
+
+  md->error = BLI_strdup(buffer);
+
+#ifndef NDEBUG
+  if ((md->mode & eModifierMode_Virtual) == 0) {
+    /* Ensure correct object is passed in. */
+    BLI_assert(BKE_modifier_get_original(ob, md) != NULL);
+  }
+#endif
+
+  UNUSED_VARS_NDEBUG(ob);
+}
+
 int BKE_modifiers_get_cage_index(const Scene *scene,
                                  Object *ob,
                                  int *r_lastPossibleCageIndex,
@@ -568,7 +603,6 @@ bool BKE_modifier_is_nonlocal_in_liboverride(const Object *ob, const ModifierDat
 }
 
 CDMaskLink *BKE_modifier_calc_data_masks(const struct Scene *scene,
-                                         Object *ob,
                                          ModifierData *md,
                                          CustomData_MeshMasks *final_datamask,
                                          int required_mode,
@@ -591,7 +625,7 @@ CDMaskLink *BKE_modifier_calc_data_masks(const struct Scene *scene,
       }
 
       if (mti->requiredDataMask) {
-        mti->requiredDataMask(ob, md, &curr->mask);
+        mti->requiredDataMask(md, &curr->mask);
       }
 
       if (previewmd == md && previewmask != NULL) {
@@ -1001,8 +1035,7 @@ void BKE_modifier_deform_vertsEM(ModifierData *md,
 
 /* end modifier callback wrappers */
 
-Mesh *BKE_modifier_get_evaluated_mesh_from_evaluated_object(Object *ob_eval,
-                                                            const bool get_cage_mesh)
+Mesh *BKE_modifier_get_evaluated_mesh_from_evaluated_object(Object *ob_eval)
 {
   Mesh *me = NULL;
 
@@ -1011,17 +1044,11 @@ Mesh *BKE_modifier_get_evaluated_mesh_from_evaluated_object(Object *ob_eval,
     BMEditMesh *em = BKE_editmesh_from_object(ob_eval);
     /* 'em' might not exist yet in some cases, just after loading a .blend file, see T57878. */
     if (em != NULL) {
-      Mesh *editmesh_eval_final = BKE_object_get_editmesh_eval_final(ob_eval);
-      Mesh *editmesh_eval_cage = BKE_object_get_editmesh_eval_cage(ob_eval);
-
-      me = (get_cage_mesh && editmesh_eval_cage != NULL) ? editmesh_eval_cage :
-                                                           editmesh_eval_final;
+      me = BKE_object_get_editmesh_eval_final(ob_eval);
     }
   }
   if (me == NULL) {
-    me = (get_cage_mesh && ob_eval->runtime.mesh_deform_eval != NULL) ?
-             ob_eval->runtime.mesh_deform_eval :
-             BKE_object_get_evaluated_mesh(ob_eval);
+    me = BKE_object_get_evaluated_mesh(ob_eval);
   }
 
   return me;
diff --git a/source/blender/blenkernel/intern/movieclip.c b/source/blender/blenkernel/intern/movieclip.c
index 19ee2ba6605..46e05b39076 100644
--- a/source/blender/blenkernel/intern/movieclip.c
+++ b/source/blender/blenkernel/intern/movieclip.c
@@ -343,7 +343,7 @@ IDTypeInfo IDType_ID_MC = {
     .foreach_id = movie_clip_foreach_id,
     .foreach_cache = movie_clip_foreach_cache,
     .foreach_path = movie_clip_foreach_path,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = movieclip_blend_write,
     .blend_read_data = movieclip_blend_read_data,
diff --git a/source/blender/blenkernel/intern/multires.c b/source/blender/blenkernel/intern/multires.c
index 63945f9ed42..ce61ca483e9 100644
--- a/source/blender/blenkernel/intern/multires.c
+++ b/source/blender/blenkernel/intern/multires.c
@@ -62,7 +62,7 @@ typedef enum {
 static void multiresModifier_disp_run(
     DerivedMesh *dm, Mesh *me, DerivedMesh *dm2, DispOp op, CCGElem **oldGridData, int totlvl);
 
-/** Customdata */
+/** Custom-data. */
 
 void multires_customdata_delete(Mesh *me)
 {
@@ -183,6 +183,7 @@ static BLI_bitmap *multires_mdisps_downsample_hidden(const BLI_bitmap *old_hidde
 
 static void multires_output_hidden_to_ccgdm(CCGDerivedMesh *ccgdm, Mesh *me, int level)
 {
+  const MPoly *polys = BKE_mesh_polys(me);
   const MDisps *mdisps = CustomData_get_layer(&me->ldata, CD_MDISPS);
   BLI_bitmap **grid_hidden = ccgdm->gridHidden;
   int *gridOffset;
@@ -191,7 +192,7 @@ static void multires_output_hidden_to_ccgdm(CCGDerivedMesh *ccgdm, Mesh *me, int
   gridOffset = ccgdm->dm.getGridOffset(&ccgdm->dm);
 
   for (i = 0; i < me->totpoly; i++) {
-    for (j = 0; j < me->mpoly[i].totloop; j++) {
+    for (j = 0; j < polys[i].totloop; j++) {
       int g = gridOffset[i] + j;
       const MDisps *md = &mdisps[g];
       BLI_bitmap *gh = md->hidden;
@@ -466,15 +467,16 @@ void multires_force_external_reload(Object *object)
 static int get_levels_from_disps(Object *ob)
 {
   Mesh *me = ob->data;
+  const MPoly *polys = BKE_mesh_polys(me);
   MDisps *mdisp, *md;
   int i, j, totlvl = 0;
 
   mdisp = CustomData_get_layer(&me->ldata, CD_MDISPS);
 
   for (i = 0; i < me->totpoly; i++) {
-    md = mdisp + me->mpoly[i].loopstart;
+    md = mdisp + polys[i].loopstart;
 
-    for (j = 0; j < me->mpoly[i].totloop; j++, md++) {
+    for (j = 0; j < polys[i].totloop; j++, md++) {
       if (md->totdisp == 0) {
         continue;
       }
@@ -633,6 +635,7 @@ static void multires_grid_paint_mask_downsample(GridPaintMask *gpm, int level)
 static void multires_del_higher(MultiresModifierData *mmd, Object *ob, int lvl)
 {
   Mesh *me = (Mesh *)ob->data;
+  const MPoly *polys = BKE_mesh_polys(me);
   int levels = mmd->totlvl - lvl;
   MDisps *mdisps;
   GridPaintMask *gpm;
@@ -652,8 +655,8 @@ static void multires_del_higher(MultiresModifierData *mmd, Object *ob, int lvl)
       int i, j;
 
       for (i = 0; i < me->totpoly; i++) {
-        for (j = 0; j < me->mpoly[i].totloop; j++) {
-          int g = me->mpoly[i].loopstart + j;
+        for (j = 0; j < polys[i].totloop; j++) {
+          int g = polys[i].loopstart + j;
           MDisps *mdisp = &mdisps[g];
           float(*disps)[3], (*ndisps)[3], (*hdisps)[3];
           int totdisp = multires_grid_tot[lvl];
@@ -828,7 +831,7 @@ typedef struct MultiresThreadedData {
   CCGElem **gridData, **subGridData;
   CCGKey *key;
   CCGKey *sub_key;
-  MPoly *mpoly;
+  const MPoly *mpoly;
   MDisps *mdisps;
   GridPaintMask *grid_paint_mask;
   int *gridOffset;
@@ -846,7 +849,7 @@ static void multires_disp_run_cb(void *__restrict userdata,
   CCGElem **gridData = tdata->gridData;
   CCGElem **subGridData = tdata->subGridData;
   CCGKey *key = tdata->key;
-  MPoly *mpoly = tdata->mpoly;
+  const MPoly *mpoly = tdata->mpoly;
   MDisps *mdisps = tdata->mdisps;
   GridPaintMask *grid_paint_mask = tdata->grid_paint_mask;
   int *gridOffset = tdata->gridOffset;
@@ -939,7 +942,7 @@ static void multiresModifier_disp_run(
   CCGDerivedMesh *ccgdm = (CCGDerivedMesh *)dm;
   CCGElem **gridData, **subGridData;
   CCGKey key;
-  MPoly *mpoly = me->mpoly;
+  const MPoly *mpoly = BKE_mesh_polys(me);
   MDisps *mdisps = CustomData_get_layer(&me->ldata, CD_MDISPS);
   GridPaintMask *grid_paint_mask = NULL;
   int *gridOffset;
@@ -960,7 +963,7 @@ static void multiresModifier_disp_run(
 
   if (!mdisps) {
     if (op == CALC_DISPLACEMENTS) {
-      mdisps = CustomData_add_layer(&me->ldata, CD_MDISPS, CD_DEFAULT, NULL, me->totloop);
+      mdisps = CustomData_add_layer(&me->ldata, CD_MDISPS, CD_SET_DEFAULT, NULL, me->totloop);
     }
     else {
       return;
@@ -1487,7 +1490,7 @@ void multires_ensure_external_read(struct Mesh *mesh, int top_level)
 
   MDisps *mdisps = CustomData_get_layer(&mesh->ldata, CD_MDISPS);
   if (mdisps == NULL) {
-    mdisps = CustomData_add_layer(&mesh->ldata, CD_MDISPS, CD_DEFAULT, NULL, mesh->totloop);
+    mdisps = CustomData_add_layer(&mesh->ldata, CD_MDISPS, CD_SET_DEFAULT, NULL, mesh->totloop);
   }
 
   const int totloop = mesh->totloop;
diff --git a/source/blender/blenkernel/intern/multires_reshape.c b/source/blender/blenkernel/intern/multires_reshape.c
index b50a0787fe3..17e4860ab1b 100644
--- a/source/blender/blenkernel/intern/multires_reshape.c
+++ b/source/blender/blenkernel/intern/multires_reshape.c
@@ -181,7 +181,8 @@ void multiresModifier_subdivide_to_level(struct Object *object,
    * are allocated at a proper level and return. */
   const bool has_mdisps = CustomData_has_layer(&coarse_mesh->ldata, CD_MDISPS);
   if (!has_mdisps) {
-    CustomData_add_layer(&coarse_mesh->ldata, CD_MDISPS, CD_CALLOC, NULL, coarse_mesh->totloop);
+    CustomData_add_layer(
+        &coarse_mesh->ldata, CD_MDISPS, CD_SET_DEFAULT, NULL, coarse_mesh->totloop);
   }
 
   /* NOTE: Subdivision happens from the top level of the existing multires modifier. If it is set
diff --git a/source/blender/blenkernel/intern/multires_reshape.h b/source/blender/blenkernel/intern/multires_reshape.h
index c4f320b86d8..5e2822ad5df 100644
--- a/source/blender/blenkernel/intern/multires_reshape.h
+++ b/source/blender/blenkernel/intern/multires_reshape.h
@@ -14,8 +14,12 @@
 struct Depsgraph;
 struct GridPaintMask;
 struct MDisps;
+struct MEdge;
 struct Mesh;
+struct MLoop;
+struct MPoly;
 struct MultiresModifierData;
+struct MVert;
 struct Object;
 struct Subdiv;
 struct SubdivCCG;
@@ -30,6 +34,10 @@ typedef struct MultiresReshapeContext {
   /* Base mesh from original object.
    * NOTE: Does NOT include any leading modifiers in it. */
   struct Mesh *base_mesh;
+  const struct MVert *base_verts;
+  const struct MEdge *base_edges;
+  const struct MPoly *base_polys;
+  const struct MLoop *base_loops;
 
   /* Subdivision surface created for multires modifier.
    *
diff --git a/source/blender/blenkernel/intern/multires_reshape_apply_base.c b/source/blender/blenkernel/intern/multires_reshape_apply_base.c
index f7d29806353..81b0abbdcf5 100644
--- a/source/blender/blenkernel/intern/multires_reshape_apply_base.c
+++ b/source/blender/blenkernel/intern/multires_reshape_apply_base.c
@@ -30,11 +30,14 @@
 void multires_reshape_apply_base_update_mesh_coords(MultiresReshapeContext *reshape_context)
 {
   Mesh *base_mesh = reshape_context->base_mesh;
-  const MLoop *mloop = base_mesh->mloop;
-  MVert *mvert = base_mesh->mvert;
+  MVert *base_verts = BKE_mesh_verts_for_write(base_mesh);
+  /* Update the context in case the vertices were duplicated. */
+  reshape_context->base_verts = base_verts;
+
+  const MLoop *mloop = reshape_context->base_loops;
   for (int loop_index = 0; loop_index < base_mesh->totloop; ++loop_index) {
     const MLoop *loop = &mloop[loop_index];
-    MVert *vert = &mvert[loop->v];
+    MVert *vert = &base_verts[loop->v];
 
     GridCoord grid_coord;
     grid_coord.grid_index = loop_index;
@@ -66,13 +69,15 @@ static float v3_dist_from_plane(const float v[3], const float center[3], const f
 void multires_reshape_apply_base_refit_base_mesh(MultiresReshapeContext *reshape_context)
 {
   Mesh *base_mesh = reshape_context->base_mesh;
-
+  MVert *base_verts = BKE_mesh_verts_for_write(base_mesh);
+  /* Update the context in case the vertices were duplicated. */
+  reshape_context->base_verts = base_verts;
   MeshElemMap *pmap;
   int *pmap_mem;
   BKE_mesh_vert_poly_map_create(&pmap,
                                 &pmap_mem,
-                                base_mesh->mpoly,
-                                base_mesh->mloop,
+                                reshape_context->base_polys,
+                                reshape_context->base_loops,
                                 base_mesh->totvert,
                                 base_mesh->totpoly,
                                 base_mesh->totloop);
@@ -80,7 +85,7 @@ void multires_reshape_apply_base_refit_base_mesh(MultiresReshapeContext *reshape
   float(*origco)[3] = MEM_calloc_arrayN(
       base_mesh->totvert, sizeof(float[3]), "multires apply base origco");
   for (int i = 0; i < base_mesh->totvert; i++) {
-    copy_v3_v3(origco[i], base_mesh->mvert[i].co);
+    copy_v3_v3(origco[i], base_verts[i].co);
   }
 
   for (int i = 0; i < base_mesh->totvert; i++) {
@@ -94,11 +99,11 @@ void multires_reshape_apply_base_refit_base_mesh(MultiresReshapeContext *reshape
     /* Find center. */
     int tot = 0;
     for (int j = 0; j < pmap[i].count; j++) {
-      const MPoly *p = &base_mesh->mpoly[pmap[i].indices[j]];
+      const MPoly *p = &reshape_context->base_polys[pmap[i].indices[j]];
 
       /* This double counts, not sure if that's bad or good. */
       for (int k = 0; k < p->totloop; k++) {
-        const int vndx = base_mesh->mloop[p->loopstart + k].v;
+        const int vndx = reshape_context->base_loops[p->loopstart + k].v;
         if (vndx != i) {
           add_v3_v3(center, origco[vndx]);
           tot++;
@@ -109,7 +114,7 @@ void multires_reshape_apply_base_refit_base_mesh(MultiresReshapeContext *reshape
 
     /* Find normal. */
     for (int j = 0; j < pmap[i].count; j++) {
-      const MPoly *p = &base_mesh->mpoly[pmap[i].indices[j]];
+      const MPoly *p = &reshape_context->base_polys[pmap[i].indices[j]];
       MPoly fake_poly;
       MLoop *fake_loops;
       float(*fake_co)[3];
@@ -122,7 +127,7 @@ void multires_reshape_apply_base_refit_base_mesh(MultiresReshapeContext *reshape
       fake_co = MEM_malloc_arrayN(p->totloop, sizeof(float[3]), "fake_co");
 
       for (int k = 0; k < p->totloop; k++) {
-        const int vndx = base_mesh->mloop[p->loopstart + k].v;
+        const int vndx = reshape_context->base_loops[p->loopstart + k].v;
 
         fake_loops[k].v = k;
 
@@ -143,10 +148,10 @@ void multires_reshape_apply_base_refit_base_mesh(MultiresReshapeContext *reshape
     normalize_v3(avg_no);
 
     /* Push vertex away from the plane. */
-    const float dist = v3_dist_from_plane(base_mesh->mvert[i].co, center, avg_no);
+    const float dist = v3_dist_from_plane(base_verts[i].co, center, avg_no);
     copy_v3_v3(push, avg_no);
     mul_v3_fl(push, dist);
-    add_v3_v3(base_mesh->mvert[i].co, push);
+    add_v3_v3(base_verts[i].co, push);
   }
 
   MEM_freeN(origco);
diff --git a/source/blender/blenkernel/intern/multires_reshape_smooth.c b/source/blender/blenkernel/intern/multires_reshape_smooth.c
index 8246de12ebf..e887f543dc5 100644
--- a/source/blender/blenkernel/intern/multires_reshape_smooth.c
+++ b/source/blender/blenkernel/intern/multires_reshape_smooth.c
@@ -354,10 +354,9 @@ static GridCoord *vertex_grid_coord_with_grid_index(const Vertex *vertex, const
 
 /* Get grid coordinates which correspond to corners of the given face.
  * All the grid coordinates will be from the same grid index. */
-static void grid_coords_from_face_vertices(
-    const MultiresReshapeSmoothContext *reshape_smooth_context,
-    const Face *face,
-    const GridCoord *grid_coords[])
+static void grid_coords_from_face_verts(const MultiresReshapeSmoothContext *reshape_smooth_context,
+                                        const Face *face,
+                                        const GridCoord *grid_coords[])
 {
   BLI_assert(face->num_corners == 4);
 
@@ -417,7 +416,7 @@ static void foreach_toplevel_grid_coord_task(void *__restrict userdata_v,
 
   const Face *face = &reshape_smooth_context->geometry.faces[face_index];
   const GridCoord *face_grid_coords[4];
-  grid_coords_from_face_vertices(reshape_smooth_context, face, face_grid_coords);
+  grid_coords_from_face_verts(reshape_smooth_context, face, face_grid_coords);
 
   for (int y = 0; y < inner_grid_size; ++y) {
     const float ptex_v = (float)y * inner_grid_size_1_inv;
@@ -643,8 +642,7 @@ static void foreach_vertex(const SubdivForeachContext *foreach_context,
   const int face_index = multires_reshape_grid_to_face_index(reshape_context,
                                                              grid_coord.grid_index);
 
-  const Mesh *base_mesh = reshape_context->base_mesh;
-  const MPoly *base_poly = &base_mesh->mpoly[face_index];
+  const MPoly *base_poly = &reshape_context->base_polys[face_index];
   const int num_corners = base_poly->totloop;
   const int start_grid_index = reshape_context->face_start_grid_index[face_index];
   const int corner = grid_coord.grid_index - start_grid_index;
@@ -834,8 +832,7 @@ static void foreach_edge(const struct SubdivForeachContext *foreach_context,
     return;
   }
   /* Edges without crease are to be ignored as well. */
-  const Mesh *base_mesh = reshape_context->base_mesh;
-  const MEdge *base_edge = &base_mesh->medge[coarse_edge_index];
+  const MEdge *base_edge = &reshape_context->base_edges[coarse_edge_index];
   const char crease = get_effective_crease_char(reshape_smooth_context, base_edge);
   if (crease == 0) {
     return;
@@ -847,9 +844,9 @@ static void geometry_init_loose_information(MultiresReshapeSmoothContext *reshap
 {
   const MultiresReshapeContext *reshape_context = reshape_smooth_context->reshape_context;
   const Mesh *base_mesh = reshape_context->base_mesh;
-  const MPoly *base_mpoly = base_mesh->mpoly;
-  const MLoop *base_mloop = base_mesh->mloop;
-  const MEdge *base_edge = base_mesh->medge;
+  const MPoly *base_mpoly = reshape_context->base_polys;
+  const MLoop *base_mloop = reshape_context->base_loops;
+  const MEdge *base_edge = reshape_context->base_edges;
 
   reshape_smooth_context->non_loose_base_edge_map = BLI_BITMAP_NEW(base_mesh->totedge,
                                                                    "non_loose_base_edge_map");
diff --git a/source/blender/blenkernel/intern/multires_reshape_subdivide.c b/source/blender/blenkernel/intern/multires_reshape_subdivide.c
index 9fa3e93a1e6..effea2467bc 100644
--- a/source/blender/blenkernel/intern/multires_reshape_subdivide.c
+++ b/source/blender/blenkernel/intern/multires_reshape_subdivide.c
@@ -28,12 +28,16 @@
 
 static void multires_subdivide_create_object_space_linear_grids(Mesh *mesh)
 {
+  const MVert *verts = BKE_mesh_verts(mesh);
+  const MPoly *polys = BKE_mesh_polys(mesh);
+  const MLoop *loops = BKE_mesh_loops(mesh);
+
   MDisps *mdisps = CustomData_get_layer(&mesh->ldata, CD_MDISPS);
   const int totpoly = mesh->totpoly;
   for (int p = 0; p < totpoly; p++) {
-    MPoly *poly = &mesh->mpoly[p];
+    const MPoly *poly = &polys[p];
     float poly_center[3];
-    BKE_mesh_calc_poly_center(poly, &mesh->mloop[poly->loopstart], mesh->mvert, poly_center);
+    BKE_mesh_calc_poly_center(poly, &loops[poly->loopstart], verts, poly_center);
     for (int l = 0; l < poly->totloop; l++) {
       const int loop_index = poly->loopstart + l;
 
@@ -44,14 +48,14 @@ static void multires_subdivide_create_object_space_linear_grids(Mesh *mesh)
       int prev_loop_index = l - 1 >= 0 ? loop_index - 1 : loop_index + poly->totloop - 1;
       int next_loop_index = l + 1 < poly->totloop ? loop_index + 1 : poly->loopstart;
 
-      MLoop *loop = &mesh->mloop[loop_index];
-      MLoop *loop_next = &mesh->mloop[next_loop_index];
-      MLoop *loop_prev = &mesh->mloop[prev_loop_index];
+      const MLoop *loop = &loops[loop_index];
+      const MLoop *loop_next = &loops[next_loop_index];
+      const MLoop *loop_prev = &loops[prev_loop_index];
 
       copy_v3_v3(disps[0], poly_center);
-      mid_v3_v3v3(disps[1], mesh->mvert[loop->v].co, mesh->mvert[loop_next->v].co);
-      mid_v3_v3v3(disps[2], mesh->mvert[loop->v].co, mesh->mvert[loop_prev->v].co);
-      copy_v3_v3(disps[3], mesh->mvert[loop->v].co);
+      mid_v3_v3v3(disps[1], verts[loop->v].co, verts[loop_next->v].co);
+      mid_v3_v3v3(disps[2], verts[loop->v].co, verts[loop_prev->v].co);
+      copy_v3_v3(disps[3], verts[loop->v].co);
     }
   }
 }
@@ -68,7 +72,8 @@ void multires_subdivide_create_tangent_displacement_linear_grids(Object *object,
 
   const bool has_mdisps = CustomData_has_layer(&coarse_mesh->ldata, CD_MDISPS);
   if (!has_mdisps) {
-    CustomData_add_layer(&coarse_mesh->ldata, CD_MDISPS, CD_CALLOC, NULL, coarse_mesh->totloop);
+    CustomData_add_layer(
+        &coarse_mesh->ldata, CD_MDISPS, CD_SET_DEFAULT, NULL, coarse_mesh->totloop);
   }
 
   if (new_top_level == 1) {
diff --git a/source/blender/blenkernel/intern/multires_reshape_util.c b/source/blender/blenkernel/intern/multires_reshape_util.c
index 34aa90aa554..5b60394feda 100644
--- a/source/blender/blenkernel/intern/multires_reshape_util.c
+++ b/source/blender/blenkernel/intern/multires_reshape_util.c
@@ -66,7 +66,7 @@ static void context_zero(MultiresReshapeContext *reshape_context)
 static void context_init_lookup(MultiresReshapeContext *reshape_context)
 {
   const Mesh *base_mesh = reshape_context->base_mesh;
-  const MPoly *mpoly = base_mesh->mpoly;
+  const MPoly *mpoly = reshape_context->base_polys;
   const int num_faces = base_mesh->totpoly;
 
   reshape_context->face_start_grid_index = MEM_malloc_arrayN(
@@ -152,6 +152,10 @@ bool multires_reshape_context_create_from_base_mesh(MultiresReshapeContext *resh
   reshape_context->mmd = mmd;
 
   reshape_context->base_mesh = base_mesh;
+  reshape_context->base_verts = BKE_mesh_verts(base_mesh);
+  reshape_context->base_edges = BKE_mesh_edges(base_mesh);
+  reshape_context->base_polys = BKE_mesh_polys(base_mesh);
+  reshape_context->base_loops = BKE_mesh_loops(base_mesh);
 
   reshape_context->subdiv = multires_reshape_create_subdiv(NULL, object, mmd);
   reshape_context->need_free_subdiv = true;
@@ -185,6 +189,10 @@ bool multires_reshape_context_create_from_object(MultiresReshapeContext *reshape
   reshape_context->mmd = mmd;
 
   reshape_context->base_mesh = base_mesh;
+  reshape_context->base_verts = BKE_mesh_verts(base_mesh);
+  reshape_context->base_edges = BKE_mesh_edges(base_mesh);
+  reshape_context->base_polys = BKE_mesh_polys(base_mesh);
+  reshape_context->base_loops = BKE_mesh_loops(base_mesh);
 
   reshape_context->subdiv = multires_reshape_create_subdiv(depsgraph, object, mmd);
   reshape_context->need_free_subdiv = true;
@@ -212,6 +220,10 @@ bool multires_reshape_context_create_from_ccg(MultiresReshapeContext *reshape_co
   context_zero(reshape_context);
 
   reshape_context->base_mesh = base_mesh;
+  reshape_context->base_verts = BKE_mesh_verts(base_mesh);
+  reshape_context->base_edges = BKE_mesh_edges(base_mesh);
+  reshape_context->base_polys = BKE_mesh_polys(base_mesh);
+  reshape_context->base_loops = BKE_mesh_loops(base_mesh);
 
   reshape_context->subdiv = subdiv_ccg->subdiv;
   reshape_context->need_free_subdiv = false;
@@ -255,6 +267,10 @@ bool multires_reshape_context_create_from_subdiv(MultiresReshapeContext *reshape
 
   reshape_context->mmd = mmd;
   reshape_context->base_mesh = base_mesh;
+  reshape_context->base_verts = BKE_mesh_verts(base_mesh);
+  reshape_context->base_edges = BKE_mesh_edges(base_mesh);
+  reshape_context->base_polys = BKE_mesh_polys(base_mesh);
+  reshape_context->base_loops = BKE_mesh_loops(base_mesh);
 
   reshape_context->subdiv = subdiv;
   reshape_context->need_free_subdiv = false;
@@ -344,7 +360,7 @@ int multires_reshape_grid_to_corner(const MultiresReshapeContext *reshape_contex
 
 bool multires_reshape_is_quad_face(const MultiresReshapeContext *reshape_context, int face_index)
 {
-  const MPoly *base_poly = &reshape_context->base_mesh->mpoly[face_index];
+  const MPoly *base_poly = &reshape_context->base_polys[face_index];
   return (base_poly->totloop == 4);
 }
 
@@ -636,8 +652,7 @@ static void foreach_grid_face_coordinate_task(void *__restrict userdata_v,
 
   const MultiresReshapeContext *reshape_context = data->reshape_context;
 
-  const Mesh *base_mesh = data->reshape_context->base_mesh;
-  const MPoly *mpoly = base_mesh->mpoly;
+  const MPoly *mpoly = reshape_context->base_polys;
   const int grid_size = data->grid_size;
   const float grid_size_1_inv = 1.0f / (((float)grid_size) - 1.0f);
 
diff --git a/source/blender/blenkernel/intern/multires_reshape_vertcos.c b/source/blender/blenkernel/intern/multires_reshape_vertcos.c
index e50f5e71bf7..7cf853e0374 100644
--- a/source/blender/blenkernel/intern/multires_reshape_vertcos.c
+++ b/source/blender/blenkernel/intern/multires_reshape_vertcos.c
@@ -52,8 +52,7 @@ static void multires_reshape_vertcos_foreach_vertex(const SubdivForeachContext *
   const int face_index = multires_reshape_grid_to_face_index(reshape_context,
                                                              grid_coord.grid_index);
 
-  const Mesh *base_mesh = reshape_context->base_mesh;
-  const MPoly *base_poly = &base_mesh->mpoly[face_index];
+  const MPoly *base_poly = &reshape_context->base_polys[face_index];
   const int num_corners = base_poly->totloop;
   const int start_grid_index = reshape_context->face_start_grid_index[face_index];
   const int corner = grid_coord.grid_index - start_grid_index;
diff --git a/source/blender/blenkernel/intern/multires_unsubdivide.c b/source/blender/blenkernel/intern/multires_unsubdivide.c
index cad680ecedd..353fbec6933 100644
--- a/source/blender/blenkernel/intern/multires_unsubdivide.c
+++ b/source/blender/blenkernel/intern/multires_unsubdivide.c
@@ -161,7 +161,7 @@ static bool is_vertex_diagonal(BMVert *from_v, BMVert *to_v)
  */
 static void unsubdivide_face_center_vertex_tag(BMesh *bm, BMVert *initial_vertex)
 {
-  bool *visited_vertices = MEM_calloc_arrayN(bm->totvert, sizeof(bool), "visited vertices");
+  bool *visited_verts = MEM_calloc_arrayN(bm->totvert, sizeof(bool), "visited vertices");
   GSQueue *queue;
   queue = BLI_gsqueue_new(sizeof(BMVert *));
 
@@ -177,7 +177,7 @@ static void unsubdivide_face_center_vertex_tag(BMesh *bm, BMVert *initial_vertex
       int neighbor_vertex_index = BM_elem_index_get(neighbor_v);
       if (neighbor_v != initial_vertex && is_vertex_diagonal(neighbor_v, initial_vertex)) {
         BLI_gsqueue_push(queue, &neighbor_v);
-        visited_vertices[neighbor_vertex_index] = true;
+        visited_verts[neighbor_vertex_index] = true;
         BM_elem_flag_set(neighbor_v, BM_ELEM_TAG, true);
       }
     }
@@ -211,10 +211,10 @@ static void unsubdivide_face_center_vertex_tag(BMesh *bm, BMVert *initial_vertex
       BM_ITER_ELEM (f, &iter, diagonal_v, BM_FACES_OF_VERT) {
         BM_ITER_ELEM (neighbor_v, &iter_a, f, BM_VERTS_OF_FACE) {
           int neighbor_vertex_index = BM_elem_index_get(neighbor_v);
-          if (!visited_vertices[neighbor_vertex_index] && neighbor_v != diagonal_v &&
+          if (!visited_verts[neighbor_vertex_index] && neighbor_v != diagonal_v &&
               is_vertex_diagonal(neighbor_v, diagonal_v)) {
             BLI_gsqueue_push(queue, &neighbor_v);
-            visited_vertices[neighbor_vertex_index] = true;
+            visited_verts[neighbor_vertex_index] = true;
             BM_elem_flag_set(neighbor_v, BM_ELEM_TAG, true);
           }
         }
@@ -224,7 +224,7 @@ static void unsubdivide_face_center_vertex_tag(BMesh *bm, BMVert *initial_vertex
   }
 
   BLI_gsqueue_free(queue);
-  MEM_freeN(visited_vertices);
+  MEM_freeN(visited_verts);
 }
 
 /**
@@ -352,14 +352,14 @@ static bool unsubdivide_tag_disconnected_mesh_element(BMesh *bm, int *elem_id, i
  */
 static int unsubdivide_init_elem_ids(BMesh *bm, int *elem_id)
 {
-  bool *visited_vertices = MEM_calloc_arrayN(bm->totvert, sizeof(bool), "visited vertices");
+  bool *visited_verts = MEM_calloc_arrayN(bm->totvert, sizeof(bool), "visited vertices");
   int current_id = 0;
   for (int i = 0; i < bm->totvert; i++) {
-    if (!visited_vertices[i]) {
+    if (!visited_verts[i]) {
       GSQueue *queue;
       queue = BLI_gsqueue_new(sizeof(BMVert *));
 
-      visited_vertices[i] = true;
+      visited_verts[i] = true;
       elem_id[i] = current_id;
       BMVert *iv = BM_vert_at_index(bm, i);
       BLI_gsqueue_push(queue, &iv);
@@ -372,8 +372,8 @@ static int unsubdivide_init_elem_ids(BMesh *bm, int *elem_id)
         BM_ITER_ELEM (ed, &iter, current_v, BM_EDGES_OF_VERT) {
           neighbor_v = BM_edge_other_vert(ed, current_v);
           const int neighbor_index = BM_elem_index_get(neighbor_v);
-          if (!visited_vertices[neighbor_index]) {
-            visited_vertices[neighbor_index] = true;
+          if (!visited_verts[neighbor_index]) {
+            visited_verts[neighbor_index] = true;
             elem_id[neighbor_index] = current_id;
             BLI_gsqueue_push(queue, &neighbor_v);
           }
@@ -383,7 +383,7 @@ static int unsubdivide_init_elem_ids(BMesh *bm, int *elem_id)
       BLI_gsqueue_free(queue);
     }
   }
-  MEM_freeN(visited_vertices);
+  MEM_freeN(visited_verts);
   return current_id;
 }
 
@@ -639,9 +639,10 @@ static void store_grid_data(MultiresUnsubdivideContext *context,
                             int grid_x,
                             int grid_y)
 {
-
   Mesh *original_mesh = context->original_mesh;
-  MPoly *poly = &original_mesh->mpoly[BM_elem_index_get(f)];
+  const MPoly *polys = BKE_mesh_polys(original_mesh);
+  const MLoop *loops = BKE_mesh_loops(original_mesh);
+  const MPoly *poly = &polys[BM_elem_index_get(f)];
 
   const int corner_vertex_index = BM_elem_index_get(v);
 
@@ -650,7 +651,7 @@ static void store_grid_data(MultiresUnsubdivideContext *context,
   int loop_offset = 0;
   for (int i = 0; i < poly->totloop; i++) {
     const int loop_index = poly->loopstart + i;
-    MLoop *l = &original_mesh->mloop[loop_index];
+    const MLoop *l = &loops[loop_index];
     if (l->v == corner_vertex_index) {
       loop_offset = i;
       break;
@@ -901,10 +902,10 @@ static void multires_unsubdivide_add_original_index_datalayers(Mesh *mesh)
   multires_unsubdivide_free_original_datalayers(mesh);
 
   int *l_index = CustomData_add_layer_named(
-      &mesh->ldata, CD_PROP_INT32, CD_CALLOC, NULL, mesh->totloop, lname);
+      &mesh->ldata, CD_PROP_INT32, CD_SET_DEFAULT, NULL, mesh->totloop, lname);
 
   int *v_index = CustomData_add_layer_named(
-      &mesh->vdata, CD_PROP_INT32, CD_CALLOC, NULL, mesh->totvert, vname);
+      &mesh->vdata, CD_PROP_INT32, CD_SET_DEFAULT, NULL, mesh->totvert, vname);
 
   /* Initialize these data-layer with the indices in the current mesh. */
   for (int i = 0; i < mesh->totloop; i++) {
@@ -918,8 +919,9 @@ static void multires_unsubdivide_add_original_index_datalayers(Mesh *mesh)
 static void multires_unsubdivide_prepare_original_bmesh_for_extract(
     MultiresUnsubdivideContext *context)
 {
-
   Mesh *original_mesh = context->original_mesh;
+  const MPoly *original_polys = BKE_mesh_polys(original_mesh);
+
   Mesh *base_mesh = context->base_mesh;
 
   BMesh *bm_original_mesh = context->bm_original_mesh = get_bmesh_from_mesh(original_mesh);
@@ -949,7 +951,7 @@ static void multires_unsubdivide_prepare_original_bmesh_for_extract(
   context->loop_to_face_map = MEM_calloc_arrayN(original_mesh->totloop, sizeof(int), "loop map");
 
   for (int i = 0; i < original_mesh->totpoly; i++) {
-    MPoly *poly = &original_mesh->mpoly[i];
+    const MPoly *poly = &original_polys[i];
     for (int l = 0; l < poly->totloop; l++) {
       int original_loop_index = l + poly->loopstart;
       context->loop_to_face_map[original_loop_index] = i;
@@ -963,16 +965,19 @@ static void multires_unsubdivide_prepare_original_bmesh_for_extract(
  */
 static bool multires_unsubdivide_flip_grid_x_axis(Mesh *mesh, int poly, int loop, int v_x)
 {
-  MPoly *p = &mesh->mpoly[poly];
+  const MPoly *polys = BKE_mesh_polys(mesh);
+  const MLoop *loops = BKE_mesh_loops(mesh);
+
+  const MPoly *p = &polys[poly];
 
-  MLoop *l_first = &mesh->mloop[p->loopstart];
+  const MLoop *l_first = &loops[p->loopstart];
   if ((loop == (p->loopstart + (p->totloop - 1))) && l_first->v == v_x) {
     return true;
   }
 
   int next_l_index = loop + 1;
   if (next_l_index < p->loopstart + p->totloop) {
-    MLoop *l_next = &mesh->mloop[next_l_index];
+    const MLoop *l_next = &loops[next_l_index];
     if (l_next->v == v_x) {
       return true;
     }
@@ -1174,7 +1179,7 @@ static void multires_create_grids_in_unsubdivided_base_mesh(MultiresUnsubdivideC
     CustomData_free_layers(&base_mesh->ldata, CD_MDISPS, base_mesh->totloop);
   }
   MDisps *mdisps = CustomData_add_layer(
-      &base_mesh->ldata, CD_MDISPS, CD_CALLOC, NULL, base_mesh->totloop);
+      &base_mesh->ldata, CD_MDISPS, CD_SET_DEFAULT, NULL, base_mesh->totloop);
 
   const int totdisp = pow_i(BKE_ccg_gridsize(context->num_total_levels), 2);
   const int totloop = base_mesh->totloop;
@@ -1247,7 +1252,7 @@ int multiresModifier_rebuild_subdiv(struct Depsgraph *depsgraph,
   }
 
   /* Copy the new base mesh to the original mesh. */
-  BKE_mesh_nomain_to_mesh(unsubdiv_context.base_mesh, object->data, object, &CD_MASK_MESH, true);
+  BKE_mesh_nomain_to_mesh(unsubdiv_context.base_mesh, object->data, object);
   Mesh *base_mesh = object->data;
   multires_create_grids_in_unsubdivided_base_mesh(&unsubdiv_context, base_mesh);
 
diff --git a/source/blender/blenkernel/intern/nla.c b/source/blender/blenkernel/intern/nla.c
index 9457c20eb7d..c0315dcc848 100644
--- a/source/blender/blenkernel/intern/nla.c
+++ b/source/blender/blenkernel/intern/nla.c
@@ -1241,7 +1241,7 @@ static NlaStrip *nlastrip_find_active(ListBase /* NlaStrip */ *strips)
 
 float BKE_nlastrip_compute_frame_from_previous_strip(NlaStrip *strip)
 {
-  float limit_prev = MINFRAMEF;
+  float limit_prev = MINAFRAMEF;
 
   /* Find the previous end frame, with a special case if the previous strip was a transition : */
   if (strip->prev) {
@@ -2072,7 +2072,7 @@ bool BKE_nla_tweakmode_enter(AnimData *adt)
 
   /* handle AnimData level changes:
    * - 'real' active action to temp storage (no need to change user-counts).
-   * - Action of active strip set to be the 'active action', and have its usercount incremented.
+   * - Action of active strip set to be the 'active action', and have its user-count incremented.
    * - Editing-flag for this AnimData block should also get turned on
    *   (for more efficient restoring).
    * - Take note of the active strip for mapping-correction of keyframes
@@ -2136,7 +2136,8 @@ void BKE_nla_tweakmode_exit(AnimData *adt)
   }
 
   /* handle AnimData level changes:
-   * - 'temporary' active action needs its usercount decreased, since we're removing this reference
+   * - 'temporary' active action needs its user-count decreased,
+   *   since we're removing this reference
    * - 'real' active action is restored from storage
    * - storage pointer gets cleared (to avoid having bad notes hanging around)
    * - editing-flag for this AnimData block should also get turned off
diff --git a/source/blender/blenkernel/intern/node.cc b/source/blender/blenkernel/intern/node.cc
index c6f140b9260..3a241efdac2 100644
--- a/source/blender/blenkernel/intern/node.cc
+++ b/source/blender/blenkernel/intern/node.cc
@@ -47,6 +47,7 @@
 
 #include "BKE_anim_data.h"
 #include "BKE_animsys.h"
+#include "BKE_asset.h"
 #include "BKE_bpath.h"
 #include "BKE_colortools.h"
 #include "BKE_context.h"
@@ -54,6 +55,7 @@
 #include "BKE_global.h"
 #include "BKE_icons.h"
 #include "BKE_idprop.h"
+#include "BKE_idprop.hh"
 #include "BKE_idtype.h"
 #include "BKE_image_format.h"
 #include "BKE_lib_id.h"
@@ -71,8 +73,8 @@
 #include "NOD_composite.h"
 #include "NOD_function.h"
 #include "NOD_geometry.h"
+#include "NOD_geometry_nodes_lazy_function.hh"
 #include "NOD_node_declaration.hh"
-#include "NOD_node_tree_ref.hh"
 #include "NOD_shader.h"
 #include "NOD_socket.h"
 #include "NOD_texture.h"
@@ -104,7 +106,6 @@ using blender::nodes::NodeDeclaration;
 using blender::nodes::OutputFieldDependency;
 using blender::nodes::OutputSocketFieldType;
 using blender::nodes::SocketDeclaration;
-using namespace blender::nodes::node_tree_ref_types;
 
 /* Fallback types for undefined tree, nodes, sockets */
 static bNodeTreeType NodeTreeTypeUndefined;
@@ -120,9 +121,6 @@ static void node_free_node(bNodeTree *ntree, bNode *node);
 static void node_socket_interface_free(bNodeTree *UNUSED(ntree),
                                        bNodeSocket *sock,
                                        const bool do_id_user);
-static void nodeMuteRerouteOutputLinks(struct bNodeTree *ntree,
-                                       struct bNode *node,
-                                       const bool mute);
 
 static void ntree_init_data(ID *id)
 {
@@ -136,7 +134,7 @@ static void ntree_copy_data(Main *UNUSED(bmain), ID *id_dst, const ID *id_src, c
   bNodeTree *ntree_dst = (bNodeTree *)id_dst;
   const bNodeTree *ntree_src = (const bNodeTree *)id_src;
 
-  /* We never handle usercount here for own data. */
+  /* We never handle user-count here for own data. */
   const int flag_subdata = flag | LIB_ID_CREATE_NO_USER_REFCOUNT;
 
   ntree_dst->runtime = MEM_new(__func__);
@@ -330,6 +328,8 @@ static void node_foreach_id(ID *id, LibraryForeachIDData *data)
 {
   bNodeTree *ntree = (bNodeTree *)id;
 
+  BKE_LIB_FOREACHID_PROCESS_ID(data, ntree->owner_id, IDWALK_CB_LOOPBACK);
+
   BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, ntree->gpd, IDWALK_CB_USER);
 
   LISTBASE_FOREACH (bNode *, node, &ntree->nodes) {
@@ -404,34 +404,19 @@ static void node_foreach_path(ID *id, BPathForeachPathData *bpath_data)
   }
 }
 
-static ID *node_owner_get(Main *bmain, ID *id)
+static ID **node_owner_pointer_get(ID *id)
 {
   if ((id->flag & LIB_EMBEDDED_DATA) == 0) {
-    return id;
+    return NULL;
   }
   /* TODO: Sort this NO_MAIN or not for embedded node trees. See T86119. */
   // BLI_assert((id->tag & LIB_TAG_NO_MAIN) == 0);
 
-  ListBase *lists[] = {&bmain->materials,
-                       &bmain->lights,
-                       &bmain->worlds,
-                       &bmain->textures,
-                       &bmain->scenes,
-                       &bmain->linestyles,
-                       &bmain->simulations,
-                       nullptr};
-
-  bNodeTree *ntree = (bNodeTree *)id;
-  for (int i = 0; lists[i] != nullptr; i++) {
-    LISTBASE_FOREACH (ID *, id_iter, lists[i]) {
-      if (ntreeFromID(id_iter) == ntree) {
-        return id_iter;
-      }
-    }
-  }
+  bNodeTree *ntree = reinterpret_cast(id);
+  BLI_assert(ntree->owner_id != NULL);
+  BLI_assert(ntreeFromID(ntree->owner_id) == ntree);
 
-  BLI_assert_msg(0, "Embedded node tree with no owner. Critical Main inconsistency.");
-  return nullptr;
+  return &ntree->owner_id;
 }
 
 static void write_node_socket_default_value(BlendWriter *writer, bNodeSocket *sock)
@@ -667,8 +652,35 @@ static void direct_link_node_socket(BlendDataReader *reader, bNodeSocket *sock)
   sock->runtime = MEM_new(__func__);
 }
 
-void ntreeBlendReadData(BlendDataReader *reader, bNodeTree *ntree)
+void ntreeBlendReadData(BlendDataReader *reader, ID *owner_id, bNodeTree *ntree)
 {
+  /* Special case for this pointer, do not rely on regular `lib_link` process here. Avoids needs
+   * for do_versioning, and ensures coherence of data in any case.
+   *
+   * NOTE: Old versions are very often 'broken' here, just fix it silently in these cases.
+   */
+  if (BLO_read_fileversion_get(reader) > 300) {
+    BLI_assert((ntree->id.flag & LIB_EMBEDDED_DATA) != 0 || owner_id == nullptr);
+  }
+  BLI_assert(owner_id == NULL || owner_id->lib == ntree->id.lib);
+  if (owner_id != nullptr && (ntree->id.flag & LIB_EMBEDDED_DATA) == 0) {
+    /* This is unfortunate, but currently a lot of existing files (including startup ones) have
+     * missing `LIB_EMBEDDED_DATA` flag.
+     *
+     * NOTE: Using do_version is not a solution here, since this code will be called before any
+     * do_version takes place. Keeping it here also ensures future (or unknown existing) similar
+     * bugs won't go easily unnoticed. */
+    if (BLO_read_fileversion_get(reader) > 300) {
+      CLOG_WARN(&LOG,
+                "Fixing root node tree '%s' owned by '%s' missing EMBEDDED tag, please consider "
+                "re-saving your (startup) file",
+                ntree->id.name,
+                owner_id->name);
+    }
+    ntree->id.flag |= LIB_EMBEDDED_DATA;
+  }
+  ntree->owner_id = owner_id;
+
   /* NOTE: writing and reading goes in sync, for speed. */
   ntree->is_updating = false;
   ntree->typeinfo = nullptr;
@@ -830,12 +842,12 @@ void ntreeBlendReadData(BlendDataReader *reader, bNodeTree *ntree)
 static void ntree_blend_read_data(BlendDataReader *reader, ID *id)
 {
   bNodeTree *ntree = (bNodeTree *)id;
-  ntreeBlendReadData(reader, ntree);
+  ntreeBlendReadData(reader, nullptr, ntree);
 }
 
 static void lib_link_node_socket(BlendLibReader *reader, Library *lib, bNodeSocket *sock)
 {
-  IDP_BlendReadLib(reader, sock->prop);
+  IDP_BlendReadLib(reader, lib, sock->prop);
 
   /* This can happen for all socket types when a file is saved in an older version of Blender than
    * it was originally created in (T86298). Some socket types still require a default value. The
@@ -901,7 +913,7 @@ void ntreeBlendReadLib(struct BlendLibReader *reader, struct bNodeTree *ntree)
   LISTBASE_FOREACH (bNode *, node, &ntree->nodes) {
     /* Link ID Properties -- and copy this comment EXACTLY for easy finding
      * of library blocks that implement this. */
-    IDP_BlendReadLib(reader, node->prop);
+    IDP_BlendReadLib(reader, lib, node->prop);
 
     BLO_read_id_address(reader, lib, &node->id);
 
@@ -912,9 +924,9 @@ void ntreeBlendReadLib(struct BlendLibReader *reader, struct bNodeTree *ntree)
   lib_link_node_sockets(reader, lib, &ntree->inputs);
   lib_link_node_sockets(reader, lib, &ntree->outputs);
 
-  /* Set node->typeinfo pointers. This is done in lib linking, after the
+  /* Set `node->typeinfo` pointers. This is done in lib linking, after the
    * first versioning that can change types still without functions that
-   * update the typeinfo pointers. Versioning after lib linking needs
+   * update the `typeinfo` pointers. Versioning after lib linking needs
    * these top be valid. */
   ntreeSetTypes(nullptr, ntree);
 
@@ -1016,6 +1028,33 @@ static void ntree_blend_read_expand(BlendExpander *expander, ID *id)
   ntreeBlendReadExpand(expander, ntree);
 }
 
+namespace blender::bke {
+
+static void node_tree_asset_pre_save(void *asset_ptr, struct AssetMetaData *asset_data)
+{
+  bNodeTree &node_tree = *static_cast(asset_ptr);
+
+  BKE_asset_metadata_idprop_ensure(asset_data, idprop::create("type", node_tree.type).release());
+  auto inputs = idprop::create_group("inputs");
+  auto outputs = idprop::create_group("outputs");
+  LISTBASE_FOREACH (const bNodeSocket *, socket, &node_tree.inputs) {
+    auto property = idprop::create(socket->name, socket->typeinfo->idname);
+    IDP_AddToGroup(inputs.get(), property.release());
+  }
+  LISTBASE_FOREACH (const bNodeSocket *, socket, &node_tree.outputs) {
+    auto property = idprop::create(socket->name, socket->typeinfo->idname);
+    IDP_AddToGroup(outputs.get(), property.release());
+  }
+  BKE_asset_metadata_idprop_ensure(asset_data, inputs.release());
+  BKE_asset_metadata_idprop_ensure(asset_data, outputs.release());
+}
+
+}  // namespace blender::bke
+
+static AssetTypeInfo AssetType_NT = {
+    /* pre_save_fn */ blender::bke::node_tree_asset_pre_save,
+};
+
 IDTypeInfo IDType_ID_NT = {
     /* id_code */ ID_NT,
     /* id_filter */ FILTER_ID_NT,
@@ -1025,7 +1064,7 @@ IDTypeInfo IDType_ID_NT = {
     /* name_plural */ "node_groups",
     /* translation_context */ BLT_I18NCONTEXT_ID_NODETREE,
     /* flags */ IDTYPE_FLAGS_APPEND_IS_REUSABLE,
-    /* asset_type_info */ nullptr,
+    /* asset_type_info */ &AssetType_NT,
 
     /* init_data */ ntree_init_data,
     /* copy_data */ ntree_copy_data,
@@ -1034,7 +1073,7 @@ IDTypeInfo IDType_ID_NT = {
     /* foreach_id */ node_foreach_id,
     /* foreach_cache */ node_foreach_cache,
     /* foreach_path */ node_foreach_path,
-    /* owner_get */ node_owner_get,
+    /* owner_pointer_get */ node_owner_pointer_get,
 
     /* blend_write */ ntree_blend_write,
     /* blend_read_data */ ntree_blend_read_data,
@@ -1071,7 +1110,7 @@ static void node_add_sockets_from_type(bNodeTree *ntree, bNode *node, bNodeType
 }
 
 /* NOTE: This function is called to initialize node data based on the type.
- * The bNodeType may not be registered at creation time of the node,
+ * The #bNodeType may not be registered at creation time of the node,
  * so this can be delayed until the node type gets registered.
  */
 static void node_init(const struct bContext *C, bNodeTree *ntree, bNode *node)
@@ -1922,6 +1961,9 @@ static void node_socket_free(bNodeSocket *sock, const bool do_id_user)
     }
     MEM_freeN(sock->default_value);
   }
+  if (sock->default_attribute_name) {
+    MEM_freeN(sock->default_attribute_name);
+  }
   MEM_delete(sock->runtime);
 }
 
@@ -2347,102 +2389,11 @@ void nodeRemLink(bNodeTree *ntree, bNodeLink *link)
   }
 }
 
-/* Check if all output links are muted or not. */
-static bool nodeMuteFromSocketLinks(const bNodeTree *ntree, const bNodeSocket *sock)
-{
-  int tot = 0;
-  int muted = 0;
-  LISTBASE_FOREACH (const bNodeLink *, link, &ntree->links) {
-    if (link->fromsock == sock) {
-      tot++;
-      if (link->flag & NODE_LINK_MUTED) {
-        muted++;
-      }
-    }
-  }
-  return tot == muted;
-}
-
-static void nodeMuteLink(bNodeLink *link)
-{
-  link->flag |= NODE_LINK_MUTED;
-  link->flag |= NODE_LINK_TEST;
-  if (!(link->tosock->flag & SOCK_MULTI_INPUT)) {
-    link->tosock->flag &= ~SOCK_IN_USE;
-  }
-}
-
-static void nodeUnMuteLink(bNodeLink *link)
-{
-  link->flag &= ~NODE_LINK_MUTED;
-  link->flag |= NODE_LINK_TEST;
-  link->tosock->flag |= SOCK_IN_USE;
-}
-
-/* Upstream muting. Always happens when unmuting but checks when muting. O(n^2) algorithm. */
-static void nodeMuteRerouteInputLinks(bNodeTree *ntree, bNode *node, const bool mute)
+void nodeLinkSetMute(bNodeTree *ntree, bNodeLink *link, const bool muted)
 {
-  if (node->type != NODE_REROUTE) {
-    return;
-  }
-  if (!mute || nodeMuteFromSocketLinks(ntree, (bNodeSocket *)node->outputs.first)) {
-    bNodeSocket *sock = (bNodeSocket *)node->inputs.first;
-    LISTBASE_FOREACH (bNodeLink *, link, &ntree->links) {
-      if (!(link->flag & NODE_LINK_VALID) || (link->tosock != sock)) {
-        continue;
-      }
-      if (mute) {
-        nodeMuteLink(link);
-      }
-      else {
-        nodeUnMuteLink(link);
-      }
-      nodeMuteRerouteInputLinks(ntree, link->fromnode, mute);
-    }
-  }
-}
-
-/* Downstream muting propagates when reaching reroute nodes. O(n^2) algorithm. */
-static void nodeMuteRerouteOutputLinks(bNodeTree *ntree, bNode *node, const bool mute)
-{
-  if (node->type != NODE_REROUTE) {
-    return;
-  }
-  bNodeSocket *sock;
-  sock = (bNodeSocket *)node->outputs.first;
-  LISTBASE_FOREACH (bNodeLink *, link, &ntree->links) {
-    if (!(link->flag & NODE_LINK_VALID) || (link->fromsock != sock)) {
-      continue;
-    }
-    if (mute) {
-      nodeMuteLink(link);
-    }
-    else {
-      nodeUnMuteLink(link);
-    }
-    nodeMuteRerouteOutputLinks(ntree, link->tonode, mute);
-  }
-}
-
-void nodeMuteLinkToggle(bNodeTree *ntree, bNodeLink *link)
-{
-  if (link->tosock) {
-    bool mute = !(link->flag & NODE_LINK_MUTED);
-    if (mute) {
-      nodeMuteLink(link);
-    }
-    else {
-      nodeUnMuteLink(link);
-    }
-    if (link->tonode->type == NODE_REROUTE) {
-      nodeMuteRerouteOutputLinks(ntree, link->tonode, mute);
-    }
-    if (link->fromnode->type == NODE_REROUTE) {
-      nodeMuteRerouteInputLinks(ntree, link->fromnode, mute);
-    }
-  }
-
-  if (ntree) {
+  const bool was_muted = link->flag & NODE_LINK_MUTED;
+  SET_FLAG_FROM_TEST(link->flag, muted, NODE_LINK_MUTED);
+  if (muted != was_muted) {
     BKE_ntree_update_tag_link_mute(ntree, link);
   }
 }
@@ -2657,29 +2608,37 @@ void nodePositionRelative(bNode *from_node,
 
 void nodePositionPropagate(bNode *node)
 {
-  LISTBASE_FOREACH (bNodeSocket *, nsock, &node->inputs) {
-    if (nsock->link != nullptr) {
-      bNodeLink *link = nsock->link;
+  LISTBASE_FOREACH (bNodeSocket *, socket, &node->inputs) {
+    if (socket->link != nullptr) {
+      bNodeLink *link = socket->link;
       nodePositionRelative(link->fromnode, link->tonode, link->fromsock, link->tosock);
       nodePositionPropagate(link->fromnode);
     }
   }
 }
 
-bNodeTree *ntreeAddTree(Main *bmain, const char *name, const char *idname)
+static bNodeTree *ntreeAddTree_do(
+    Main *bmain, ID *owner_id, const bool is_embedded, const char *name, const char *idname)
 {
   /* trees are created as local trees for compositor, material or texture nodes,
    * node groups and other tree types are created as library data.
    */
-  const bool is_embedded = (bmain == nullptr);
   int flag = 0;
-  if (is_embedded) {
+  if (is_embedded || bmain == nullptr) {
     flag |= LIB_ID_CREATE_NO_MAIN;
   }
   bNodeTree *ntree = (bNodeTree *)BKE_libblock_alloc(bmain, ID_NT, name, flag);
   BKE_libblock_init_empty(&ntree->id);
   if (is_embedded) {
+    BLI_assert(owner_id != NULL);
     ntree->id.flag |= LIB_EMBEDDED_DATA;
+    ntree->owner_id = owner_id;
+    bNodeTree **ntree_owner_ptr = BKE_ntree_ptr_from_id(owner_id);
+    BLI_assert(ntree_owner_ptr != NULL);
+    *ntree_owner_ptr = ntree;
+  }
+  else {
+    BLI_assert(owner_id == NULL);
   }
 
   BLI_strncpy(ntree->idname, idname, sizeof(ntree->idname));
@@ -2688,6 +2647,19 @@ bNodeTree *ntreeAddTree(Main *bmain, const char *name, const char *idname)
   return ntree;
 }
 
+bNodeTree *ntreeAddTree(Main *bmain, const char *name, const char *idname)
+{
+  return ntreeAddTree_do(bmain, nullptr, false, name, idname);
+}
+
+bNodeTree *ntreeAddTreeEmbedded(Main *UNUSED(bmain),
+                                ID *owner_id,
+                                const char *name,
+                                const char *idname)
+{
+  return ntreeAddTree_do(nullptr, owner_id, true, name, idname);
+}
+
 bNodeTree *ntreeCopyTree_ex(const bNodeTree *ntree, Main *bmain, const bool do_id_user)
 {
   const int flag = do_id_user ? 0 : LIB_ID_CREATE_NO_USER_REFCOUNT | LIB_ID_CREATE_NO_MAIN;
@@ -3047,7 +3019,9 @@ void nodeRemoveNode(Main *bmain, bNodeTree *ntree, bNode *node, bool do_id_user)
     }
   }
 
-  if (node_has_id) {
+  /* Also update relations for the scene time node, which causes a dependency
+   * on time that users expect to be removed when the node is removed. */
+  if (node_has_id || node->type == GEO_NODE_INPUT_SCENE_TIME) {
     if (bmain != nullptr) {
       DEG_relations_tag_update(bmain);
     }
@@ -3074,6 +3048,9 @@ static void node_socket_interface_free(bNodeTree *UNUSED(ntree),
     }
     MEM_freeN(sock->default_value);
   }
+  if (sock->default_attribute_name) {
+    MEM_freeN(sock->default_attribute_name);
+  }
   MEM_delete(sock->runtime);
 }
 
@@ -3376,8 +3353,10 @@ struct bNodeSocket *ntreeAddSocketInterfaceFromSocket(bNodeTree *ntree,
                                                       bNode *from_node,
                                                       bNodeSocket *from_sock)
 {
-  bNodeSocket *iosock = ntreeAddSocketInterface(
-      ntree, static_cast(from_sock->in_out), from_sock->idname, from_sock->name);
+  bNodeSocket *iosock = ntreeAddSocketInterface(ntree,
+                                                static_cast(from_sock->in_out),
+                                                from_sock->idname,
+                                                DATA_(from_sock->name));
   if (iosock) {
     if (iosock->typeinfo->interface_from_socket) {
       iosock->typeinfo->interface_from_socket(ntree, iosock, from_node, from_sock);
@@ -4574,6 +4553,7 @@ static void registerShaderNodes()
   register_node_type_sh_wavelength();
   register_node_type_sh_blackbody();
   register_node_type_sh_mix_rgb();
+  register_node_type_sh_mix();
   register_node_type_sh_valtorgb();
   register_node_type_sh_rgbtobw();
   register_node_type_sh_shadertorgb();
@@ -4751,17 +4731,18 @@ static void registerGeometryNodes()
   register_node_type_geo_curve_trim();
   register_node_type_geo_deform_curves_on_surface();
   register_node_type_geo_delete_geometry();
-  register_node_type_geo_duplicate_elements();
+  register_node_type_geo_distribute_points_in_volume();
   register_node_type_geo_distribute_points_on_faces();
   register_node_type_geo_dual_mesh();
+  register_node_type_geo_duplicate_elements();
+  register_node_type_geo_edge_paths_to_curves();
+  register_node_type_geo_edge_paths_to_selection();
   register_node_type_geo_edge_split();
   register_node_type_geo_extrude_mesh();
   register_node_type_geo_field_at_index();
-  register_node_type_geo_field_on_domain();
   register_node_type_geo_flip_faces();
   register_node_type_geo_geometry_to_instance();
   register_node_type_geo_image_texture();
-  register_node_type_geo_input_named_attribute();
   register_node_type_geo_input_curve_handles();
   register_node_type_geo_input_curve_tilt();
   register_node_type_geo_input_id();
@@ -4778,22 +4759,26 @@ static void registerGeometryNodes()
   register_node_type_geo_input_mesh_face_neighbors();
   register_node_type_geo_input_mesh_island();
   register_node_type_geo_input_mesh_vertex_neighbors();
+  register_node_type_geo_input_named_attribute();
   register_node_type_geo_input_normal();
   register_node_type_geo_input_position();
   register_node_type_geo_input_radius();
   register_node_type_geo_input_scene_time();
   register_node_type_geo_input_shade_smooth();
+  register_node_type_geo_input_shortest_edge_paths();
   register_node_type_geo_input_spline_cyclic();
   register_node_type_geo_input_spline_length();
   register_node_type_geo_input_spline_resolution();
   register_node_type_geo_input_tangent();
   register_node_type_geo_instance_on_points();
   register_node_type_geo_instances_to_points();
+  register_node_type_geo_interpolate_domain();
   register_node_type_geo_is_viewport();
   register_node_type_geo_join_geometry();
   register_node_type_geo_material_replace();
   register_node_type_geo_material_selection();
   register_node_type_geo_merge_by_distance();
+  register_node_type_geo_mesh_face_set_boundaries();
   register_node_type_geo_mesh_primitive_circle();
   register_node_type_geo_mesh_primitive_cone();
   register_node_type_geo_mesh_primitive_cube();
@@ -4807,9 +4792,9 @@ static void registerGeometryNodes()
   register_node_type_geo_mesh_to_points();
   register_node_type_geo_mesh_to_volume();
   register_node_type_geo_object_info();
-  register_node_type_geo_points();
   register_node_type_geo_points_to_vertices();
   register_node_type_geo_points_to_volume();
+  register_node_type_geo_points();
   register_node_type_geo_proximity();
   register_node_type_geo_raycast();
   register_node_type_geo_realize_instances();
@@ -4839,11 +4824,11 @@ static void registerGeometryNodes()
   register_node_type_geo_transform();
   register_node_type_geo_translate_instances();
   register_node_type_geo_triangulate();
+  register_node_type_geo_uv_pack_islands();
+  register_node_type_geo_uv_unwrap();
   register_node_type_geo_viewer();
   register_node_type_geo_volume_cube();
   register_node_type_geo_volume_to_mesh();
-  register_node_type_geo_uv_pack_islands();
-  register_node_type_geo_uv_unwrap();
 }
 
 static void registerFunctionNodes()
diff --git a/source/blender/blenkernel/intern/node_runtime.cc b/source/blender/blenkernel/intern/node_runtime.cc
new file mode 100644
index 00000000000..4fb0e423a33
--- /dev/null
+++ b/source/blender/blenkernel/intern/node_runtime.cc
@@ -0,0 +1,432 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "BKE_node.h"
+#include "BKE_node_runtime.hh"
+
+#include "DNA_node_types.h"
+
+#include "BLI_function_ref.hh"
+#include "BLI_stack.hh"
+#include "BLI_task.hh"
+#include "BLI_timeit.hh"
+
+#include "NOD_geometry_nodes_lazy_function.hh"
+
+namespace blender::bke::node_tree_runtime {
+
+void preprocess_geometry_node_tree_for_evaluation(bNodeTree &tree_cow)
+{
+  BLI_assert(tree_cow.type == NTREE_GEOMETRY);
+  /* Rebuild geometry nodes lazy function graph. */
+  tree_cow.runtime->geometry_nodes_lazy_function_graph_info.reset();
+  blender::nodes::ensure_geometry_nodes_lazy_function_graph(tree_cow);
+}
+
+static void double_checked_lock(std::mutex &mutex, bool &data_is_dirty, FunctionRef fn)
+{
+  if (!data_is_dirty) {
+    return;
+  }
+  std::lock_guard lock{mutex};
+  if (!data_is_dirty) {
+    return;
+  }
+  fn();
+  data_is_dirty = false;
+}
+
+static void double_checked_lock_with_task_isolation(std::mutex &mutex,
+                                                    bool &data_is_dirty,
+                                                    FunctionRef fn)
+{
+  double_checked_lock(mutex, data_is_dirty, [&]() { threading::isolate_task(fn); });
+}
+
+static void update_node_vector(const bNodeTree &ntree)
+{
+  bNodeTreeRuntime &tree_runtime = *ntree.runtime;
+  tree_runtime.nodes.clear();
+  tree_runtime.group_nodes.clear();
+  tree_runtime.has_undefined_nodes_or_sockets = false;
+  LISTBASE_FOREACH (bNode *, node, &ntree.nodes) {
+    node->runtime->index_in_tree = tree_runtime.nodes.append_and_get_index(node);
+    node->runtime->owner_tree = const_cast(&ntree);
+    tree_runtime.has_undefined_nodes_or_sockets |= node->typeinfo == &NodeTypeUndefined;
+    if (node->is_group()) {
+      tree_runtime.group_nodes.append(node);
+    }
+  }
+}
+
+static void update_link_vector(const bNodeTree &ntree)
+{
+  bNodeTreeRuntime &tree_runtime = *ntree.runtime;
+  tree_runtime.links.clear();
+  LISTBASE_FOREACH (bNodeLink *, link, &ntree.links) {
+    tree_runtime.links.append(link);
+  }
+}
+
+static void update_internal_links(const bNodeTree &ntree)
+{
+  bNodeTreeRuntime &tree_runtime = *ntree.runtime;
+  for (bNode *node : tree_runtime.nodes) {
+    node->runtime->internal_links.clear();
+    for (bNodeSocket *socket : node->runtime->outputs) {
+      socket->runtime->internal_link_input = nullptr;
+    }
+    LISTBASE_FOREACH (bNodeLink *, link, &node->internal_links) {
+      node->runtime->internal_links.append(link);
+      link->tosock->runtime->internal_link_input = link->fromsock;
+    }
+  }
+}
+
+static void update_socket_vectors_and_owner_node(const bNodeTree &ntree)
+{
+  bNodeTreeRuntime &tree_runtime = *ntree.runtime;
+  tree_runtime.sockets.clear();
+  tree_runtime.input_sockets.clear();
+  tree_runtime.output_sockets.clear();
+  for (bNode *node : tree_runtime.nodes) {
+    bNodeRuntime &node_runtime = *node->runtime;
+    node_runtime.inputs.clear();
+    node_runtime.outputs.clear();
+    LISTBASE_FOREACH (bNodeSocket *, socket, &node->inputs) {
+      socket->runtime->index_in_node = node_runtime.inputs.append_and_get_index(socket);
+      socket->runtime->index_in_all_sockets = tree_runtime.sockets.append_and_get_index(socket);
+      socket->runtime->index_in_inout_sockets = tree_runtime.input_sockets.append_and_get_index(
+          socket);
+      socket->runtime->owner_node = node;
+      tree_runtime.has_undefined_nodes_or_sockets |= socket->typeinfo == &NodeSocketTypeUndefined;
+    }
+    LISTBASE_FOREACH (bNodeSocket *, socket, &node->outputs) {
+      socket->runtime->index_in_node = node_runtime.outputs.append_and_get_index(socket);
+      socket->runtime->index_in_all_sockets = tree_runtime.sockets.append_and_get_index(socket);
+      socket->runtime->index_in_inout_sockets = tree_runtime.output_sockets.append_and_get_index(
+          socket);
+      socket->runtime->owner_node = node;
+      tree_runtime.has_undefined_nodes_or_sockets |= socket->typeinfo == &NodeSocketTypeUndefined;
+    }
+  }
+}
+
+static void update_directly_linked_links_and_sockets(const bNodeTree &ntree)
+{
+  bNodeTreeRuntime &tree_runtime = *ntree.runtime;
+  for (bNode *node : tree_runtime.nodes) {
+    for (bNodeSocket *socket : node->runtime->inputs) {
+      socket->runtime->directly_linked_links.clear();
+      socket->runtime->directly_linked_sockets.clear();
+    }
+    for (bNodeSocket *socket : node->runtime->outputs) {
+      socket->runtime->directly_linked_links.clear();
+      socket->runtime->directly_linked_sockets.clear();
+    }
+    node->runtime->has_available_linked_inputs = false;
+    node->runtime->has_available_linked_outputs = false;
+  }
+  for (bNodeLink *link : tree_runtime.links) {
+    link->fromsock->runtime->directly_linked_links.append(link);
+    link->fromsock->runtime->directly_linked_sockets.append(link->tosock);
+    link->tosock->runtime->directly_linked_links.append(link);
+    if (link->is_available()) {
+      link->fromnode->runtime->has_available_linked_outputs = true;
+      link->tonode->runtime->has_available_linked_inputs = true;
+    }
+  }
+  for (bNodeSocket *socket : tree_runtime.input_sockets) {
+    if (socket->flag & SOCK_MULTI_INPUT) {
+      std::sort(socket->runtime->directly_linked_links.begin(),
+                socket->runtime->directly_linked_links.end(),
+                [&](const bNodeLink *a, const bNodeLink *b) {
+                  return a->multi_input_socket_index > b->multi_input_socket_index;
+                });
+    }
+  }
+  for (bNodeSocket *socket : tree_runtime.input_sockets) {
+    for (bNodeLink *link : socket->runtime->directly_linked_links) {
+      /* Do this after sorting the input links. */
+      socket->runtime->directly_linked_sockets.append(link->fromsock);
+    }
+  }
+}
+
+static void find_logical_origins_for_socket_recursive(
+    bNodeSocket &input_socket,
+    bool only_follow_first_input_link,
+    Vector &sockets_in_current_chain,
+    Vector &r_logical_origins,
+    Vector &r_skipped_origins)
+{
+  if (sockets_in_current_chain.contains(&input_socket)) {
+    /* Protect against reroute recursions. */
+    return;
+  }
+  sockets_in_current_chain.append(&input_socket);
+
+  Span links_to_check = input_socket.runtime->directly_linked_links;
+  if (only_follow_first_input_link) {
+    links_to_check = links_to_check.take_front(1);
+  }
+  for (bNodeLink *link : links_to_check) {
+    if (link->is_muted()) {
+      continue;
+    }
+    if (!link->is_available()) {
+      continue;
+    }
+    bNodeSocket &origin_socket = *link->fromsock;
+    bNode &origin_node = *link->fromnode;
+    if (!origin_socket.is_available()) {
+      /* Non available sockets are ignored. */
+      continue;
+    }
+    if (origin_node.type == NODE_REROUTE) {
+      bNodeSocket &reroute_input = *origin_node.runtime->inputs[0];
+      bNodeSocket &reroute_output = *origin_node.runtime->outputs[0];
+      r_skipped_origins.append(&reroute_input);
+      r_skipped_origins.append(&reroute_output);
+      find_logical_origins_for_socket_recursive(
+          reroute_input, false, sockets_in_current_chain, r_logical_origins, r_skipped_origins);
+      continue;
+    }
+    if (origin_node.is_muted()) {
+      if (bNodeSocket *mute_input = origin_socket.runtime->internal_link_input) {
+        r_skipped_origins.append(&origin_socket);
+        r_skipped_origins.append(mute_input);
+        find_logical_origins_for_socket_recursive(
+            *mute_input, true, sockets_in_current_chain, r_logical_origins, r_skipped_origins);
+      }
+      continue;
+    }
+    r_logical_origins.append(&origin_socket);
+  }
+
+  sockets_in_current_chain.pop_last();
+}
+
+static void update_logical_origins(const bNodeTree &ntree)
+{
+  bNodeTreeRuntime &tree_runtime = *ntree.runtime;
+  threading::parallel_for(tree_runtime.nodes.index_range(), 128, [&](const IndexRange range) {
+    for (const int i : range) {
+      bNode &node = *tree_runtime.nodes[i];
+      for (bNodeSocket *socket : node.runtime->inputs) {
+        Vector sockets_in_current_chain;
+        socket->runtime->logically_linked_sockets.clear();
+        socket->runtime->logically_linked_skipped_sockets.clear();
+        find_logical_origins_for_socket_recursive(
+            *socket,
+            false,
+            sockets_in_current_chain,
+            socket->runtime->logically_linked_sockets,
+            socket->runtime->logically_linked_skipped_sockets);
+      }
+    }
+  });
+}
+
+static void update_nodes_by_type(const bNodeTree &ntree)
+{
+  bNodeTreeRuntime &tree_runtime = *ntree.runtime;
+  tree_runtime.nodes_by_type.clear();
+  for (bNode *node : tree_runtime.nodes) {
+    tree_runtime.nodes_by_type.add(node->typeinfo, node);
+  }
+}
+
+static void update_sockets_by_identifier(const bNodeTree &ntree)
+{
+  bNodeTreeRuntime &tree_runtime = *ntree.runtime;
+  threading::parallel_for(tree_runtime.nodes.index_range(), 128, [&](const IndexRange range) {
+    for (bNode *node : tree_runtime.nodes.as_span().slice(range)) {
+      node->runtime->inputs_by_identifier.clear();
+      node->runtime->outputs_by_identifier.clear();
+      for (bNodeSocket *socket : node->runtime->inputs) {
+        node->runtime->inputs_by_identifier.add_new(socket->identifier, socket);
+      }
+      for (bNodeSocket *socket : node->runtime->outputs) {
+        node->runtime->outputs_by_identifier.add_new(socket->identifier, socket);
+      }
+    }
+  });
+}
+
+enum class ToposortDirection {
+  LeftToRight,
+  RightToLeft,
+};
+
+struct ToposortNodeState {
+  bool is_done = false;
+  bool is_in_stack = false;
+};
+
+static void toposort_from_start_node(const ToposortDirection direction,
+                                     bNode &start_node,
+                                     MutableSpan node_states,
+                                     Vector &r_sorted_nodes,
+                                     bool &r_cycle_detected)
+{
+  struct Item {
+    bNode *node;
+    int socket_index = 0;
+    int link_index = 0;
+  };
+
+  Stack nodes_to_check;
+  nodes_to_check.push({&start_node});
+  node_states[start_node.runtime->index_in_tree].is_in_stack = true;
+  while (!nodes_to_check.is_empty()) {
+    Item &item = nodes_to_check.peek();
+    bNode &node = *item.node;
+    const Span sockets = (direction == ToposortDirection::LeftToRight) ?
+                                            node.runtime->inputs :
+                                            node.runtime->outputs;
+    while (true) {
+      if (item.socket_index == sockets.size()) {
+        /* All sockets have already been visited. */
+        break;
+      }
+      bNodeSocket &socket = *sockets[item.socket_index];
+      const Span linked_links = socket.runtime->directly_linked_links;
+      if (item.link_index == linked_links.size()) {
+        /* All links connected to this socket have already been visited. */
+        item.socket_index++;
+        item.link_index = 0;
+        continue;
+      }
+      bNodeLink &link = *linked_links[item.link_index];
+      if (!link.is_available()) {
+        /* Ignore unavailable links. */
+        item.link_index++;
+        continue;
+      }
+      bNodeSocket &linked_socket = *socket.runtime->directly_linked_sockets[item.link_index];
+      bNode &linked_node = *linked_socket.runtime->owner_node;
+      ToposortNodeState &linked_node_state = node_states[linked_node.runtime->index_in_tree];
+      if (linked_node_state.is_done) {
+        /* The linked node has already been visited. */
+        item.link_index++;
+        continue;
+      }
+      if (linked_node_state.is_in_stack) {
+        r_cycle_detected = true;
+      }
+      else {
+        nodes_to_check.push({&linked_node});
+        linked_node_state.is_in_stack = true;
+      }
+      break;
+    }
+
+    /* If no other element has been pushed, the current node can be pushed to the sorted list. */
+    if (&item == &nodes_to_check.peek()) {
+      ToposortNodeState &node_state = node_states[node.runtime->index_in_tree];
+      node_state.is_done = true;
+      node_state.is_in_stack = false;
+      r_sorted_nodes.append(&node);
+      nodes_to_check.pop();
+    }
+  }
+}
+
+static void update_toposort(const bNodeTree &ntree,
+                            const ToposortDirection direction,
+                            Vector &r_sorted_nodes,
+                            bool &r_cycle_detected)
+{
+  bNodeTreeRuntime &tree_runtime = *ntree.runtime;
+  r_sorted_nodes.clear();
+  r_sorted_nodes.reserve(tree_runtime.nodes.size());
+  r_cycle_detected = false;
+
+  Array node_states(tree_runtime.nodes.size());
+  for (bNode *node : tree_runtime.nodes) {
+    if (node_states[node->runtime->index_in_tree].is_done) {
+      /* Ignore nodes that are done already. */
+      continue;
+    }
+    if ((direction == ToposortDirection::LeftToRight) ?
+            node->runtime->has_available_linked_outputs :
+            node->runtime->has_available_linked_inputs) {
+      /* Ignore non-start nodes. */
+      continue;
+    }
+    toposort_from_start_node(direction, *node, node_states, r_sorted_nodes, r_cycle_detected);
+  }
+
+  if (r_sorted_nodes.size() < tree_runtime.nodes.size()) {
+    r_cycle_detected = true;
+    for (bNode *node : tree_runtime.nodes) {
+      if (node_states[node->runtime->index_in_tree].is_done) {
+        /* Ignore nodes that are done already. */
+        continue;
+      }
+      /* Start toposort at this node which is somewhere in the middle of a loop. */
+      toposort_from_start_node(direction, *node, node_states, r_sorted_nodes, r_cycle_detected);
+    }
+  }
+
+  BLI_assert(tree_runtime.nodes.size() == r_sorted_nodes.size());
+}
+
+static void update_group_output_node(const bNodeTree &ntree)
+{
+  bNodeTreeRuntime &tree_runtime = *ntree.runtime;
+  const bNodeType *node_type = nodeTypeFind("NodeGroupOutput");
+  const Span group_output_nodes = tree_runtime.nodes_by_type.lookup(node_type);
+  if (group_output_nodes.is_empty()) {
+    tree_runtime.group_output_node = nullptr;
+  }
+  else if (group_output_nodes.size() == 1) {
+    tree_runtime.group_output_node = group_output_nodes[0];
+  }
+  else {
+    for (bNode *group_output : group_output_nodes) {
+      if (group_output->flag & NODE_DO_OUTPUT) {
+        tree_runtime.group_output_node = group_output;
+        break;
+      }
+    }
+  }
+}
+
+static void ensure_topology_cache(const bNodeTree &ntree)
+{
+  bNodeTreeRuntime &tree_runtime = *ntree.runtime;
+  double_checked_lock_with_task_isolation(
+      tree_runtime.topology_cache_mutex, tree_runtime.topology_cache_is_dirty, [&]() {
+        update_node_vector(ntree);
+        update_link_vector(ntree);
+        update_socket_vectors_and_owner_node(ntree);
+        update_internal_links(ntree);
+        update_directly_linked_links_and_sockets(ntree);
+        threading::parallel_invoke([&]() { update_logical_origins(ntree); },
+                                   [&]() { update_nodes_by_type(ntree); },
+                                   [&]() { update_sockets_by_identifier(ntree); },
+                                   [&]() {
+                                     update_toposort(ntree,
+                                                     ToposortDirection::LeftToRight,
+                                                     tree_runtime.toposort_left_to_right,
+                                                     tree_runtime.has_available_link_cycle);
+                                   },
+                                   [&]() {
+                                     bool dummy;
+                                     update_toposort(ntree,
+                                                     ToposortDirection::RightToLeft,
+                                                     tree_runtime.toposort_right_to_left,
+                                                     dummy);
+                                   });
+        update_group_output_node(ntree);
+        tree_runtime.topology_cache_exists = true;
+      });
+}
+
+}  // namespace blender::bke::node_tree_runtime
+
+void bNodeTree::ensure_topology_cache() const
+{
+  blender::bke::node_tree_runtime::ensure_topology_cache(*this);
+}
diff --git a/source/blender/blenkernel/intern/node_tree_update.cc b/source/blender/blenkernel/intern/node_tree_update.cc
index 019ab114b83..f9bab0959c9 100644
--- a/source/blender/blenkernel/intern/node_tree_update.cc
+++ b/source/blender/blenkernel/intern/node_tree_update.cc
@@ -5,6 +5,7 @@
 #include "BLI_noise.hh"
 #include "BLI_set.hh"
 #include "BLI_stack.hh"
+#include "BLI_timeit.hh"
 #include "BLI_vector_set.hh"
 
 #include "DNA_anim_types.h"
@@ -21,7 +22,6 @@
 #include "MOD_nodes.h"
 
 #include "NOD_node_declaration.hh"
-#include "NOD_node_tree_ref.hh"
 #include "NOD_texture.h"
 
 #include "DEG_depsgraph_query.h"
@@ -50,6 +50,7 @@ enum eNodeTreeChangedFlag {
 static void add_tree_tag(bNodeTree *ntree, const eNodeTreeChangedFlag flag)
 {
   ntree->runtime->changed_flag |= flag;
+  ntree->runtime->topology_cache_is_dirty = true;
 }
 
 static void add_node_tag(bNodeTree *ntree, bNode *node, const eNodeTreeChangedFlag flag)
@@ -73,28 +74,32 @@ static bool is_field_socket_type(eNodeSocketDatatype type)
   return ELEM(type, SOCK_FLOAT, SOCK_INT, SOCK_BOOLEAN, SOCK_VECTOR, SOCK_RGBA);
 }
 
-static bool is_field_socket_type(const SocketRef &socket)
+static bool is_field_socket_type(const bNodeSocket &socket)
 {
-  return is_field_socket_type((eNodeSocketDatatype)socket.typeinfo()->type);
+  return is_field_socket_type((eNodeSocketDatatype)socket.typeinfo->type);
 }
 
-static InputSocketFieldType get_interface_input_field_type(const NodeRef &node,
-                                                           const InputSocketRef &socket)
+static InputSocketFieldType get_interface_input_field_type(const bNode &node,
+                                                           const bNodeSocket &socket)
 {
   if (!is_field_socket_type(socket)) {
     return InputSocketFieldType::None;
   }
-  if (node.is_reroute_node()) {
+  if (node.type == NODE_REROUTE) {
     return InputSocketFieldType::IsSupported;
   }
-  if (node.is_group_output_node()) {
+  if (node.type == NODE_GROUP_OUTPUT) {
     /* Outputs always support fields when the data type is correct. */
     return InputSocketFieldType::IsSupported;
   }
-  if (node.is_undefined()) {
+  if (node.typeinfo == &NodeTypeUndefined) {
+    return InputSocketFieldType::None;
+  }
+  if (node.type == NODE_CUSTOM) {
     return InputSocketFieldType::None;
   }
 
+  /* TODO: Ensure declaration exists. */
   const NodeDeclaration *node_decl = node.declaration();
 
   /* Node declarations should be implemented for nodes involved here. */
@@ -113,22 +118,25 @@ static InputSocketFieldType get_interface_input_field_type(const NodeRef &node,
   return field_type;
 }
 
-static OutputFieldDependency get_interface_output_field_dependency(const NodeRef &node,
-                                                                   const OutputSocketRef &socket)
+static OutputFieldDependency get_interface_output_field_dependency(const bNode &node,
+                                                                   const bNodeSocket &socket)
 {
   if (!is_field_socket_type(socket)) {
     /* Non-field sockets always output data. */
     return OutputFieldDependency::ForDataSource();
   }
-  if (node.is_reroute_node()) {
+  if (node.type == NODE_REROUTE) {
     /* The reroute just forwards what is passed in. */
     return OutputFieldDependency::ForDependentField();
   }
-  if (node.is_group_input_node()) {
+  if (node.type == NODE_GROUP_INPUT) {
     /* Input nodes get special treatment in #determine_group_input_states. */
     return OutputFieldDependency::ForDependentField();
   }
-  if (node.is_undefined()) {
+  if (node.typeinfo == &NodeTypeUndefined) {
+    return OutputFieldDependency::ForDataSource();
+  }
+  if (node.type == NODE_CUSTOM) {
     return OutputFieldDependency::ForDataSource();
   }
 
@@ -147,12 +155,13 @@ static OutputFieldDependency get_interface_output_field_dependency(const NodeRef
   return socket_decl.output_field_dependency();
 }
 
-static FieldInferencingInterface get_dummy_field_inferencing_interface(const NodeRef &node)
+static FieldInferencingInterface get_dummy_field_inferencing_interface(const bNode &node)
 {
   FieldInferencingInterface inferencing_interface;
-  inferencing_interface.inputs.append_n_times(InputSocketFieldType::None, node.inputs().size());
+  inferencing_interface.inputs.append_n_times(InputSocketFieldType::None,
+                                              node.input_sockets().size());
   inferencing_interface.outputs.append_n_times(OutputFieldDependency::ForDataSource(),
-                                               node.outputs().size());
+                                               node.output_sockets().size());
   return inferencing_interface;
 }
 
@@ -161,11 +170,11 @@ static FieldInferencingInterface get_dummy_field_inferencing_interface(const Nod
  * In the future, this information can be stored in the node declaration. This would allow this
  * function to return a reference, making it more efficient.
  */
-static FieldInferencingInterface get_node_field_inferencing_interface(const NodeRef &node)
+static FieldInferencingInterface get_node_field_inferencing_interface(const bNode &node)
 {
   /* Node groups already reference all required information, so just return that. */
-  if (node.is_group_node()) {
-    bNodeTree *group = (bNodeTree *)node.bnode()->id;
+  if (node.is_group()) {
+    bNodeTree *group = (bNodeTree *)node.id;
     if (group == nullptr) {
       return FieldInferencingInterface();
     }
@@ -181,11 +190,11 @@ static FieldInferencingInterface get_node_field_inferencing_interface(const Node
   }
 
   FieldInferencingInterface inferencing_interface;
-  for (const InputSocketRef *input_socket : node.inputs()) {
+  for (const bNodeSocket *input_socket : node.input_sockets()) {
     inferencing_interface.inputs.append(get_interface_input_field_type(node, *input_socket));
   }
 
-  for (const OutputSocketRef *output_socket : node.outputs()) {
+  for (const bNodeSocket *output_socket : node.output_sockets()) {
     inferencing_interface.outputs.append(
         get_interface_output_field_dependency(node, *output_socket));
   }
@@ -209,11 +218,11 @@ struct SocketFieldState {
   bool requires_single = false;
 };
 
-static Vector gather_input_socket_dependencies(
-    const OutputFieldDependency &field_dependency, const NodeRef &node)
+static Vector gather_input_socket_dependencies(
+    const OutputFieldDependency &field_dependency, const bNode &node)
 {
   const OutputSocketFieldType type = field_dependency.field_type();
-  Vector input_sockets;
+  Vector input_sockets;
   switch (type) {
     case OutputSocketFieldType::FieldSource:
     case OutputSocketFieldType::None: {
@@ -221,13 +230,13 @@ static Vector gather_input_socket_dependencies(
     }
     case OutputSocketFieldType::DependentField: {
       /* This output depends on all inputs. */
-      input_sockets.extend(node.inputs());
+      input_sockets.extend(node.input_sockets());
       break;
     }
     case OutputSocketFieldType::PartiallyDependent: {
       /* This output depends only on a few inputs. */
       for (const int i : field_dependency.linked_input_indices()) {
-        input_sockets.append(&node.input(i));
+        input_sockets.append(&node.input_socket(i));
       }
       break;
     }
@@ -240,8 +249,7 @@ static Vector gather_input_socket_dependencies(
  * to figure out if it is always a field or if it depends on any group inputs.
  */
 static OutputFieldDependency find_group_output_dependencies(
-    const InputSocketRef &group_output_socket,
-    const Span field_state_by_socket_id)
+    const bNodeSocket &group_output_socket, const Span field_state_by_socket_id)
 {
   if (!is_field_socket_type(group_output_socket)) {
     return OutputFieldDependency::ForDataSource();
@@ -249,8 +257,8 @@ static OutputFieldDependency find_group_output_dependencies(
 
   /* Use a Set here instead of an array indexed by socket id, because we my only need to look at
    * very few sockets. */
-  Set handled_sockets;
-  Stack sockets_to_check;
+  Set handled_sockets;
+  Stack sockets_to_check;
 
   handled_sockets.add(&group_output_socket);
   sockets_to_check.push(&group_output_socket);
@@ -259,20 +267,21 @@ static OutputFieldDependency find_group_output_dependencies(
   Vector linked_input_indices;
 
   while (!sockets_to_check.is_empty()) {
-    const InputSocketRef *input_socket = sockets_to_check.pop();
+    const bNodeSocket *input_socket = sockets_to_check.pop();
 
     if (!input_socket->is_directly_linked() &&
-        !field_state_by_socket_id[input_socket->id()].is_single) {
+        !field_state_by_socket_id[input_socket->index_in_tree()].is_single) {
       /* This socket uses a field as input by default. */
       return OutputFieldDependency::ForFieldSource();
     }
 
-    for (const OutputSocketRef *origin_socket : input_socket->directly_linked_sockets()) {
-      const NodeRef &origin_node = origin_socket->node();
-      const SocketFieldState &origin_state = field_state_by_socket_id[origin_socket->id()];
+    for (const bNodeSocket *origin_socket : input_socket->directly_linked_sockets()) {
+      const bNode &origin_node = origin_socket->owner_node();
+      const SocketFieldState &origin_state =
+          field_state_by_socket_id[origin_socket->index_in_tree()];
 
       if (origin_state.is_field_source) {
-        if (origin_node.is_group_input_node()) {
+        if (origin_node.type == NODE_GROUP_INPUT) {
           /* Found a group input that the group output depends on. */
           linked_input_indices.append_non_duplicates(origin_socket->index());
         }
@@ -288,12 +297,12 @@ static OutputFieldDependency find_group_output_dependencies(
             inferencing_interface.outputs[origin_socket->index()];
 
         /* Propagate search further to the left. */
-        for (const InputSocketRef *origin_input_socket :
+        for (const bNodeSocket *origin_input_socket :
              gather_input_socket_dependencies(field_dependency, origin_node)) {
           if (!origin_input_socket->is_available()) {
             continue;
           }
-          if (!field_state_by_socket_id[origin_input_socket->id()].is_single) {
+          if (!field_state_by_socket_id[origin_input_socket->index_in_tree()].is_single) {
             if (handled_sockets.add(origin_input_socket)) {
               sockets_to_check.push(origin_input_socket);
             }
@@ -306,17 +315,16 @@ static OutputFieldDependency find_group_output_dependencies(
 }
 
 static void propagate_data_requirements_from_right_to_left(
-    const NodeTreeRef &tree, const MutableSpan field_state_by_socket_id)
+    const bNodeTree &tree, const MutableSpan field_state_by_socket_id)
 {
-  const NodeTreeRef::ToposortResult toposort_result = tree.toposort(
-      NodeTreeRef::ToposortDirection::RightToLeft);
+  const Span toposort_result = tree.toposort_right_to_left();
 
-  for (const NodeRef *node : toposort_result.sorted_nodes) {
+  for (const bNode *node : toposort_result) {
     const FieldInferencingInterface inferencing_interface = get_node_field_inferencing_interface(
         *node);
 
-    for (const OutputSocketRef *output_socket : node->outputs()) {
-      SocketFieldState &state = field_state_by_socket_id[output_socket->id()];
+    for (const bNodeSocket *output_socket : node->output_sockets()) {
+      SocketFieldState &state = field_state_by_socket_id[output_socket->index_in_tree()];
 
       const OutputFieldDependency &field_dependency =
           inferencing_interface.outputs[output_socket->index()];
@@ -332,17 +340,18 @@ static void propagate_data_requirements_from_right_to_left(
 
       /* The output is required to be a single value when it is connected to any input that does
        * not support fields. */
-      for (const InputSocketRef *target_socket : output_socket->directly_linked_sockets()) {
+      for (const bNodeSocket *target_socket : output_socket->directly_linked_sockets()) {
         if (target_socket->is_available()) {
-          state.requires_single |= field_state_by_socket_id[target_socket->id()].requires_single;
+          state.requires_single |=
+              field_state_by_socket_id[target_socket->index_in_tree()].requires_single;
         }
       }
 
       if (state.requires_single) {
         bool any_input_is_field_implicitly = false;
-        const Vector connected_inputs = gather_input_socket_dependencies(
+        const Vector connected_inputs = gather_input_socket_dependencies(
             field_dependency, *node);
-        for (const InputSocketRef *input_socket : connected_inputs) {
+        for (const bNodeSocket *input_socket : connected_inputs) {
           if (!input_socket->is_available()) {
             continue;
           }
@@ -361,16 +370,16 @@ static void propagate_data_requirements_from_right_to_left(
         else {
           /* If the output is required to be a single value, the connected inputs in the same node
            * must not be fields as well. */
-          for (const InputSocketRef *input_socket : connected_inputs) {
-            field_state_by_socket_id[input_socket->id()].requires_single = true;
+          for (const bNodeSocket *input_socket : connected_inputs) {
+            field_state_by_socket_id[input_socket->index_in_tree()].requires_single = true;
           }
         }
       }
     }
 
     /* Some inputs do not require fields independent of what the outputs are connected to. */
-    for (const InputSocketRef *input_socket : node->inputs()) {
-      SocketFieldState &state = field_state_by_socket_id[input_socket->id()];
+    for (const bNodeSocket *input_socket : node->input_sockets()) {
+      SocketFieldState &state = field_state_by_socket_id[input_socket->index_in_tree()];
       if (inferencing_interface.inputs[input_socket->index()] == InputSocketFieldType::None) {
         state.requires_single = true;
         state.is_always_single = true;
@@ -380,14 +389,14 @@ static void propagate_data_requirements_from_right_to_left(
 }
 
 static void determine_group_input_states(
-    const NodeTreeRef &tree,
+    const bNodeTree &tree,
     FieldInferencingInterface &new_inferencing_interface,
     const MutableSpan field_state_by_socket_id)
 {
   {
     /* Non-field inputs never support fields. */
     int index;
-    LISTBASE_FOREACH_INDEX (bNodeSocket *, group_input, &tree.btree()->inputs, index) {
+    LISTBASE_FOREACH_INDEX (bNodeSocket *, group_input, &tree.inputs, index) {
       if (!is_field_socket_type((eNodeSocketDatatype)group_input->type)) {
         new_inferencing_interface.inputs[index] = InputSocketFieldType::None;
       }
@@ -395,18 +404,18 @@ static void determine_group_input_states(
   }
   /* Check if group inputs are required to be single values, because they are (indirectly)
    * connected to some socket that does not support fields. */
-  for (const NodeRef *node : tree.nodes_by_type("NodeGroupInput")) {
-    for (const OutputSocketRef *output_socket : node->outputs().drop_back(1)) {
-      SocketFieldState &state = field_state_by_socket_id[output_socket->id()];
+  for (const bNode *node : tree.nodes_by_type("NodeGroupInput")) {
+    for (const bNodeSocket *output_socket : node->output_sockets().drop_back(1)) {
+      SocketFieldState &state = field_state_by_socket_id[output_socket->index_in_tree()];
       if (state.requires_single) {
         new_inferencing_interface.inputs[output_socket->index()] = InputSocketFieldType::None;
       }
     }
   }
   /* If an input does not support fields, this should be reflected in all Group Input nodes. */
-  for (const NodeRef *node : tree.nodes_by_type("NodeGroupInput")) {
-    for (const OutputSocketRef *output_socket : node->outputs().drop_back(1)) {
-      SocketFieldState &state = field_state_by_socket_id[output_socket->id()];
+  for (const bNode *node : tree.nodes_by_type("NodeGroupInput")) {
+    for (const bNodeSocket *output_socket : node->output_sockets().drop_back(1)) {
+      SocketFieldState &state = field_state_by_socket_id[output_socket->index_in_tree()];
       const bool supports_field = new_inferencing_interface.inputs[output_socket->index()] !=
                                   InputSocketFieldType::None;
       if (supports_field) {
@@ -417,19 +426,19 @@ static void determine_group_input_states(
         state.requires_single = true;
       }
     }
-    SocketFieldState &dummy_socket_state = field_state_by_socket_id[node->outputs().last()->id()];
+    SocketFieldState &dummy_socket_state =
+        field_state_by_socket_id[node->output_sockets().last()->index_in_tree()];
     dummy_socket_state.requires_single = true;
   }
 }
 
 static void propagate_field_status_from_left_to_right(
-    const NodeTreeRef &tree, const MutableSpan field_state_by_socket_id)
+    const bNodeTree &tree, const MutableSpan field_state_by_socket_id)
 {
-  const NodeTreeRef::ToposortResult toposort_result = tree.toposort(
-      NodeTreeRef::ToposortDirection::LeftToRight);
+  const Span toposort_result = tree.toposort_left_to_right();
 
-  for (const NodeRef *node : toposort_result.sorted_nodes) {
-    if (node->is_group_input_node()) {
+  for (const bNode *node : toposort_result) {
+    if (node->type == NODE_GROUP_INPUT) {
       continue;
     }
 
@@ -437,22 +446,22 @@ static void propagate_field_status_from_left_to_right(
         *node);
 
     /* Update field state of input sockets, also taking into account linked origin sockets. */
-    for (const InputSocketRef *input_socket : node->inputs()) {
-      SocketFieldState &state = field_state_by_socket_id[input_socket->id()];
+    for (const bNodeSocket *input_socket : node->input_sockets()) {
+      SocketFieldState &state = field_state_by_socket_id[input_socket->index_in_tree()];
       if (state.is_always_single) {
         state.is_single = true;
         continue;
       }
       state.is_single = true;
-      if (input_socket->directly_linked_sockets().is_empty()) {
+      if (!input_socket->is_directly_linked()) {
         if (inferencing_interface.inputs[input_socket->index()] ==
             InputSocketFieldType::Implicit) {
           state.is_single = false;
         }
       }
       else {
-        for (const OutputSocketRef *origin_socket : input_socket->directly_linked_sockets()) {
-          if (!field_state_by_socket_id[origin_socket->id()].is_single) {
+        for (const bNodeSocket *origin_socket : input_socket->directly_linked_sockets()) {
+          if (!field_state_by_socket_id[origin_socket->index_in_tree()].is_single) {
             state.is_single = false;
             break;
           }
@@ -461,8 +470,8 @@ static void propagate_field_status_from_left_to_right(
     }
 
     /* Update field state of output sockets, also taking into account input sockets. */
-    for (const OutputSocketRef *output_socket : node->outputs()) {
-      SocketFieldState &state = field_state_by_socket_id[output_socket->id()];
+    for (const bNodeSocket *output_socket : node->output_sockets()) {
+      SocketFieldState &state = field_state_by_socket_id[output_socket->index_in_tree()];
       const OutputFieldDependency &field_dependency =
           inferencing_interface.outputs[output_socket->index()];
 
@@ -478,12 +487,12 @@ static void propagate_field_status_from_left_to_right(
         }
         case OutputSocketFieldType::PartiallyDependent:
         case OutputSocketFieldType::DependentField: {
-          for (const InputSocketRef *input_socket :
+          for (const bNodeSocket *input_socket :
                gather_input_socket_dependencies(field_dependency, *node)) {
             if (!input_socket->is_available()) {
               continue;
             }
-            if (!field_state_by_socket_id[input_socket->id()].is_single) {
+            if (!field_state_by_socket_id[input_socket->index_in_tree()].is_single) {
               state.is_single = false;
               break;
             }
@@ -495,17 +504,18 @@ static void propagate_field_status_from_left_to_right(
   }
 }
 
-static void determine_group_output_states(const NodeTreeRef &tree,
+static void determine_group_output_states(const bNodeTree &tree,
                                           FieldInferencingInterface &new_inferencing_interface,
                                           const Span field_state_by_socket_id)
 {
-  for (const NodeRef *group_output_node : tree.nodes_by_type("NodeGroupOutput")) {
+  for (const bNode *group_output_node : tree.nodes_by_type("NodeGroupOutput")) {
     /* Ignore inactive group output nodes. */
-    if (!(group_output_node->bnode()->flag & NODE_DO_OUTPUT)) {
+    if (!(group_output_node->flag & NODE_DO_OUTPUT)) {
       continue;
     }
     /* Determine dependencies of all group outputs. */
-    for (const InputSocketRef *group_output_socket : group_output_node->inputs().drop_back(1)) {
+    for (const bNodeSocket *group_output_socket :
+         group_output_node->input_sockets().drop_back(1)) {
       OutputFieldDependency field_dependency = find_group_output_dependencies(
           *group_output_socket, field_state_by_socket_id);
       new_inferencing_interface.outputs[group_output_socket->index()] = std::move(
@@ -515,7 +525,7 @@ static void determine_group_output_states(const NodeTreeRef &tree,
   }
 }
 
-static void update_socket_shapes(const NodeTreeRef &tree,
+static void update_socket_shapes(const bNodeTree &tree,
                                  const Span field_state_by_socket_id)
 {
   const eNodeSocketDisplayShape requires_data_shape = SOCK_DISPLAY_SHAPE_CIRCLE;
@@ -535,32 +545,30 @@ static void update_socket_shapes(const NodeTreeRef &tree,
     return data_but_can_be_field_shape;
   };
 
-  for (const InputSocketRef *socket : tree.input_sockets()) {
-    bNodeSocket *bsocket = socket->bsocket();
-    const SocketFieldState &state = field_state_by_socket_id[socket->id()];
-    bsocket->display_shape = get_shape_for_state(state);
+  for (const bNodeSocket *socket : tree.all_input_sockets()) {
+    const SocketFieldState &state = field_state_by_socket_id[socket->index_in_tree()];
+    const_cast(socket)->display_shape = get_shape_for_state(state);
   }
-  for (const OutputSocketRef *socket : tree.output_sockets()) {
-    bNodeSocket *bsocket = socket->bsocket();
-    const SocketFieldState &state = field_state_by_socket_id[socket->id()];
-    bsocket->display_shape = get_shape_for_state(state);
+  for (const bNodeSocket *socket : tree.all_sockets()) {
+    const SocketFieldState &state = field_state_by_socket_id[socket->index_in_tree()];
+    const_cast(socket)->display_shape = get_shape_for_state(state);
   }
 }
 
-static bool update_field_inferencing(const NodeTreeRef &tree)
+static bool update_field_inferencing(const bNodeTree &tree)
 {
-  bNodeTree &btree = *tree.btree();
+  tree.ensure_topology_cache();
 
   /* Create new inferencing interface for this node group. */
   std::unique_ptr new_inferencing_interface =
       std::make_unique();
-  new_inferencing_interface->inputs.resize(BLI_listbase_count(&btree.inputs),
+  new_inferencing_interface->inputs.resize(BLI_listbase_count(&tree.inputs),
                                            InputSocketFieldType::IsSupported);
-  new_inferencing_interface->outputs.resize(BLI_listbase_count(&btree.outputs),
+  new_inferencing_interface->outputs.resize(BLI_listbase_count(&tree.outputs),
                                             OutputFieldDependency::ForDataSource());
 
   /* Keep track of the state of all sockets. The index into this array is #SocketRef::id(). */
-  Array field_state_by_socket_id(tree.sockets().size());
+  Array field_state_by_socket_id(tree.all_sockets().size());
 
   propagate_data_requirements_from_right_to_left(tree, field_state_by_socket_id);
   determine_group_input_states(tree, *new_inferencing_interface, field_state_by_socket_id);
@@ -569,10 +577,10 @@ static bool update_field_inferencing(const NodeTreeRef &tree)
   update_socket_shapes(tree, field_state_by_socket_id);
 
   /* Update the previous group interface. */
-  const bool group_interface_changed = !btree.runtime->field_inferencing_interface ||
-                                       *btree.runtime->field_inferencing_interface !=
+  const bool group_interface_changed = !tree.runtime->field_inferencing_interface ||
+                                       *tree.runtime->field_inferencing_interface !=
                                            *new_inferencing_interface;
-  btree.runtime->field_inferencing_interface = std::move(new_inferencing_interface);
+  tree.runtime->field_inferencing_interface = std::move(new_inferencing_interface);
 
   return group_interface_changed;
 }
@@ -973,29 +981,22 @@ class NodeTreeMainUpdater {
   {
     TreeUpdateResult result;
 
-    /* Use a #NodeTreeRef to speedup certain queries. It is rebuilt whenever the node tree topology
-     * changes, which typically happens zero or one times during the entire update of the node
-     * tree. */
-    std::unique_ptr tree_ref;
-    this->ensure_tree_ref(ntree, tree_ref);
-
-    this->update_socket_link_and_use(*tree_ref);
-    this->update_individual_nodes(ntree, tree_ref);
-    this->update_internal_links(ntree, tree_ref);
-    this->update_generic_callback(ntree, tree_ref);
+    this->update_socket_link_and_use(ntree);
+    this->update_individual_nodes(ntree);
+    this->update_internal_links(ntree);
+    this->update_generic_callback(ntree);
     this->remove_unused_previews_when_necessary(ntree);
 
-    this->ensure_tree_ref(ntree, tree_ref);
-    this->propagate_runtime_flags(*tree_ref);
+    this->propagate_runtime_flags(ntree);
     if (ntree.type == NTREE_GEOMETRY) {
-      if (node_field_inferencing::update_field_inferencing(*tree_ref)) {
+      if (node_field_inferencing::update_field_inferencing(ntree)) {
         result.interface_changed = true;
       }
     }
 
-    result.output_changed = this->check_if_output_changed(*tree_ref);
+    result.output_changed = this->check_if_output_changed(ntree);
 
-    this->update_socket_link_and_use(*tree_ref);
+    this->update_socket_link_and_use(ntree);
     this->update_node_levels(ntree);
     this->update_link_validation(ntree);
 
@@ -1015,86 +1016,83 @@ class NodeTreeMainUpdater {
     return result;
   }
 
-  void ensure_tree_ref(bNodeTree &ntree, std::unique_ptr &tree_ref)
-  {
-    if (!tree_ref) {
-      tree_ref = std::make_unique(&ntree);
-    }
-  }
-
-  void update_socket_link_and_use(const NodeTreeRef &tree)
+  void update_socket_link_and_use(bNodeTree &tree)
   {
-    for (const InputSocketRef *socket : tree.input_sockets()) {
-      bNodeSocket *bsocket = socket->bsocket();
+    tree.ensure_topology_cache();
+    for (bNodeSocket *socket : tree.all_input_sockets()) {
       if (socket->directly_linked_links().is_empty()) {
-        bsocket->link = nullptr;
+        socket->link = nullptr;
       }
       else {
-        bsocket->link = socket->directly_linked_links()[0]->blink();
+        socket->link = socket->directly_linked_links()[0];
       }
     }
 
     this->update_socket_used_tags(tree);
   }
 
-  void update_socket_used_tags(const NodeTreeRef &tree)
+  void update_socket_used_tags(bNodeTree &tree)
   {
-    for (const SocketRef *socket : tree.sockets()) {
-      bNodeSocket *bsocket = socket->bsocket();
-      bsocket->flag &= ~SOCK_IN_USE;
-      for (const LinkRef *link : socket->directly_linked_links()) {
+    tree.ensure_topology_cache();
+    for (bNodeSocket *socket : tree.all_sockets()) {
+      socket->flag &= ~SOCK_IN_USE;
+      for (const bNodeLink *link : socket->directly_linked_links()) {
         if (!link->is_muted()) {
-          bsocket->flag |= SOCK_IN_USE;
+          socket->flag |= SOCK_IN_USE;
           break;
         }
       }
     }
   }
 
-  void update_individual_nodes(bNodeTree &ntree, std::unique_ptr &tree_ref)
+  void update_individual_nodes(bNodeTree &ntree)
   {
-    /* Iterate over nodes instead of #NodeTreeRef, because the #tree_ref might be outdated after
-     * some update functions. */
-    LISTBASE_FOREACH (bNode *, bnode, &ntree.nodes) {
-      this->ensure_tree_ref(ntree, tree_ref);
-      const NodeRef &node = *tree_ref->find_node(*bnode);
-      if (this->should_update_individual_node(node)) {
-        const uint32_t old_changed_flag = ntree.runtime->changed_flag;
-        ntree.runtime->changed_flag = NTREE_CHANGED_NOTHING;
-
-        /* This may set #ntree.runtime->changed_flag which is detected below. */
-        this->update_individual_node(node);
-
-        if (ntree.runtime->changed_flag != NTREE_CHANGED_NOTHING) {
-          /* The tree ref is outdated and needs to be rebuilt. Generally, only very few update
-           * functions change the node. Typically zero or one nodes change after an update. */
-          tree_ref.reset();
+    Vector group_inout_nodes;
+    LISTBASE_FOREACH (bNode *, node, &ntree.nodes) {
+      nodeDeclarationEnsure(&ntree, node);
+      if (this->should_update_individual_node(ntree, *node)) {
+        bNodeType &ntype = *node->typeinfo;
+        if (ntype.group_update_func) {
+          ntype.group_update_func(&ntree, node);
         }
-        ntree.runtime->changed_flag |= old_changed_flag;
+        if (ntype.updatefunc) {
+          ntype.updatefunc(&ntree, node);
+        }
+      }
+      if (ELEM(node->type, NODE_GROUP_INPUT, NODE_GROUP_OUTPUT)) {
+        group_inout_nodes.append(node);
+      }
+    }
+    /* The update function of group input/output nodes may add new interface sockets. When that
+     * happens, all the input/output nodes have to be updated again. In the future it would be
+     * better to move this functionality out of the node update function into the operator that's
+     * supposed to create the new interface socket. */
+    if (ntree.runtime->changed_flag & NTREE_CHANGED_INTERFACE) {
+      for (bNode *node : group_inout_nodes) {
+        node->typeinfo->updatefunc(&ntree, node);
       }
     }
   }
 
-  bool should_update_individual_node(const NodeRef &node)
+  bool should_update_individual_node(const bNodeTree &ntree, const bNode &node)
   {
-    bNodeTree &ntree = *node.btree();
-    bNode &bnode = *node.bnode();
     if (ntree.runtime->changed_flag & NTREE_CHANGED_ANY) {
       return true;
     }
-    if (bnode.runtime->changed_flag & NTREE_CHANGED_NODE_PROPERTY) {
+    if (node.runtime->changed_flag & NTREE_CHANGED_NODE_PROPERTY) {
       return true;
     }
     if (ntree.runtime->changed_flag & NTREE_CHANGED_LINK) {
+      ntree.ensure_topology_cache();
       /* Node groups currently always rebuilt their sockets when they are updated.
        * So avoid calling the update method when no new link was added to it. */
-      if (node.is_group_input_node()) {
-        if (node.outputs().last()->is_directly_linked()) {
+      if (node.type == NODE_GROUP_INPUT) {
+        if (node.output_sockets().last()->is_directly_linked()) {
           return true;
         }
       }
-      else if (node.is_group_output_node()) {
-        if (node.inputs().last()->is_directly_linked()) {
+      else if (node.type == NODE_GROUP_OUTPUT) {
+        if (node.input_sockets().last()->is_directly_linked()) {
           return true;
         }
       }
@@ -1104,95 +1102,76 @@ class NodeTreeMainUpdater {
       }
     }
     if (ntree.runtime->changed_flag & NTREE_CHANGED_INTERFACE) {
-      if (node.is_group_input_node() || node.is_group_output_node()) {
+      if (ELEM(node.type, NODE_GROUP_INPUT, NODE_GROUP_OUTPUT)) {
         return true;
       }
     }
     return false;
   }
 
-  void update_individual_node(const NodeRef &node)
-  {
-    bNodeTree &ntree = *node.btree();
-    bNode &bnode = *node.bnode();
-    bNodeType &ntype = *bnode.typeinfo;
-    if (ntype.group_update_func) {
-      ntype.group_update_func(&ntree, &bnode);
-    }
-    if (ntype.updatefunc) {
-      ntype.updatefunc(&ntree, &bnode);
-    }
-  }
-
-  void update_internal_links(bNodeTree &ntree, std::unique_ptr &tree_ref)
+  void update_internal_links(bNodeTree &ntree)
   {
-    bool any_internal_links_updated = false;
-    this->ensure_tree_ref(ntree, tree_ref);
-    for (const NodeRef *node : tree_ref->nodes()) {
-      if (!this->should_update_individual_node(*node)) {
+    bke::node_tree_runtime::AllowUsingOutdatedInfo allow_outdated_info{ntree};
+    ntree.ensure_topology_cache();
+    for (bNode *node : ntree.all_nodes()) {
+      if (!this->should_update_individual_node(ntree, *node)) {
         continue;
       }
       /* Find all expected internal links. */
       Vector> expected_internal_links;
-      for (const OutputSocketRef *output_socket : node->outputs()) {
+      for (const bNodeSocket *output_socket : node->output_sockets()) {
         if (!output_socket->is_available()) {
           continue;
         }
         if (!output_socket->is_directly_linked()) {
           continue;
         }
-        if (output_socket->bsocket()->flag & SOCK_NO_INTERNAL_LINK) {
+        if (output_socket->flag & SOCK_NO_INTERNAL_LINK) {
           continue;
         }
-        const InputSocketRef *input_socket = this->find_internally_linked_input(output_socket);
+        const bNodeSocket *input_socket = this->find_internally_linked_input(output_socket);
         if (input_socket != nullptr) {
-          expected_internal_links.append({input_socket->bsocket(), output_socket->bsocket()});
+          expected_internal_links.append(
+              {const_cast(input_socket), const_cast(output_socket)});
         }
       }
-      /* rebuilt internal links if they have changed. */
-      if (node->internal_links().size() != expected_internal_links.size()) {
-        this->update_internal_links_in_node(ntree, *node->bnode(), expected_internal_links);
-        any_internal_links_updated = true;
+      /* Rebuilt internal links if they have changed. */
+      if (node->internal_links_span().size() != expected_internal_links.size()) {
+        this->update_internal_links_in_node(ntree, *node, expected_internal_links);
       }
       else {
         for (auto &item : expected_internal_links) {
           const bNodeSocket *from_socket = item.first;
           const bNodeSocket *to_socket = item.second;
           bool found = false;
-          for (const InternalLinkRef *internal_link : node->internal_links()) {
-            if (from_socket == internal_link->from().bsocket() &&
-                to_socket == internal_link->to().bsocket()) {
+          for (const bNodeLink *internal_link : node->internal_links_span()) {
+            if (from_socket == internal_link->fromsock && to_socket == internal_link->tosock) {
               found = true;
             }
           }
           if (!found) {
-            this->update_internal_links_in_node(ntree, *node->bnode(), expected_internal_links);
-            any_internal_links_updated = true;
+            this->update_internal_links_in_node(ntree, *node, expected_internal_links);
             break;
           }
         }
       }
     }
-
-    if (any_internal_links_updated) {
-      tree_ref.reset();
-    }
   }
 
-  const InputSocketRef *find_internally_linked_input(const OutputSocketRef *output_socket)
+  const bNodeSocket *find_internally_linked_input(const bNodeSocket *output_socket)
   {
-    const InputSocketRef *selected_socket = nullptr;
+    const bNodeSocket *selected_socket = nullptr;
     int selected_priority = -1;
     bool selected_is_linked = false;
-    for (const InputSocketRef *input_socket : output_socket->node().inputs()) {
+    for (const bNodeSocket *input_socket : output_socket->owner_node().input_sockets()) {
       if (!input_socket->is_available()) {
         continue;
       }
-      if (input_socket->bsocket()->flag & SOCK_NO_INTERNAL_LINK) {
+      if (input_socket->flag & SOCK_NO_INTERNAL_LINK) {
         continue;
       }
-      const int priority = get_internal_link_type_priority(input_socket->bsocket()->typeinfo,
-                                                           output_socket->bsocket()->typeinfo);
+      const int priority = get_internal_link_type_priority(input_socket->typeinfo,
+                                                           output_socket->typeinfo);
       if (priority < 0) {
         continue;
       }
@@ -1227,23 +1206,12 @@ class NodeTreeMainUpdater {
     BKE_ntree_update_tag_node_internal_link(&ntree, &node);
   }
 
-  void update_generic_callback(bNodeTree &ntree, std::unique_ptr &tree_ref)
+  void update_generic_callback(bNodeTree &ntree)
   {
     if (ntree.typeinfo->update == nullptr) {
       return;
     }
-
-    /* Reset the changed_flag to allow detecting when the update callback changed the node tree. */
-    const uint32_t old_changed_flag = ntree.runtime->changed_flag;
-    ntree.runtime->changed_flag = NTREE_CHANGED_NOTHING;
-
     ntree.typeinfo->update(&ntree);
-
-    if (ntree.runtime->changed_flag != NTREE_CHANGED_NOTHING) {
-      /* The tree ref is outdated and needs to be rebuilt. */
-      tree_ref.reset();
-    }
-    ntree.runtime->changed_flag |= old_changed_flag;
   }
 
   void remove_unused_previews_when_necessary(bNodeTree &ntree)
@@ -1258,25 +1226,26 @@ class NodeTreeMainUpdater {
     BKE_node_preview_remove_unused(&ntree);
   }
 
-  void propagate_runtime_flags(const NodeTreeRef &tree_ref)
+  void propagate_runtime_flags(const bNodeTree &ntree)
   {
-    bNodeTree &ntree = *tree_ref.btree();
+    ntree.ensure_topology_cache();
+
     ntree.runtime->runtime_flag = 0;
     if (ntree.type != NTREE_SHADER) {
       return;
     }
 
     /* Check if a used node group has an animated image. */
-    for (const NodeRef *group_node : tree_ref.nodes_by_type("NodeGroup")) {
-      const bNodeTree *group = reinterpret_cast(group_node->bnode()->id);
+    for (const bNode *group_node : ntree.nodes_by_type("ShaderNodeGroup")) {
+      const bNodeTree *group = reinterpret_cast(group_node->id);
       if (group != nullptr) {
         ntree.runtime->runtime_flag |= group->runtime->runtime_flag;
       }
     }
     /* Check if the tree itself has an animated image. */
     for (const StringRefNull idname : {"ShaderNodeTexImage", "ShaderNodeTexEnvironment"}) {
-      for (const NodeRef *node : tree_ref.nodes_by_type(idname)) {
-        Image *image = reinterpret_cast(node->bnode()->id);
+      for (const bNode *node : ntree.nodes_by_type(idname)) {
+        Image *image = reinterpret_cast(node->id);
         if (image != nullptr && BKE_image_is_animated(image)) {
           ntree.runtime->runtime_flag |= NTREE_RUNTIME_FLAG_HAS_IMAGE_ANIMATION;
           break;
@@ -1288,7 +1257,7 @@ class NodeTreeMainUpdater {
                                        "ShaderNodeOutputLight",
                                        "ShaderNodeOutputWorld",
                                        "ShaderNodeOutputAOV"}) {
-      const Span nodes = tree_ref.nodes_by_type(idname);
+      const Span nodes = ntree.nodes_by_type(idname);
       if (!nodes.is_empty()) {
         ntree.runtime->runtime_flag |= NTREE_RUNTIME_FLAG_HAS_MATERIAL_OUTPUT;
         break;
@@ -1319,20 +1288,20 @@ class NodeTreeMainUpdater {
     }
   }
 
-  bool check_if_output_changed(const NodeTreeRef &tree)
+  bool check_if_output_changed(const bNodeTree &tree)
   {
-    bNodeTree &btree = *tree.btree();
+    tree.ensure_topology_cache();
 
     /* Compute a hash that represents the node topology connected to the output. This always has to
      * be updated even if it is not used to detect changes right now. Otherwise
      * #btree.runtime.output_topology_hash will go out of date. */
-    const Vector tree_output_sockets = this->find_output_sockets(tree);
-    const uint32_t old_topology_hash = btree.runtime->output_topology_hash;
+    const Vector tree_output_sockets = this->find_output_sockets(tree);
+    const uint32_t old_topology_hash = tree.runtime->output_topology_hash;
     const uint32_t new_topology_hash = this->get_combined_socket_topology_hash(
         tree, tree_output_sockets);
-    btree.runtime->output_topology_hash = new_topology_hash;
+    tree.runtime->output_topology_hash = new_topology_hash;
 
-    if (const AnimData *adt = BKE_animdata_from_id(&btree.id)) {
+    if (const AnimData *adt = BKE_animdata_from_id(&tree.id)) {
       /* Drivers may copy values in the node tree around arbitrarily and may cause the output to
        * change even if it wouldn't without drivers. Only some special drivers like `frame/5` can
        * be used without causing updates all the time currently. In the future we could try to
@@ -1354,7 +1323,7 @@ class NodeTreeMainUpdater {
       }
     }
 
-    if (btree.runtime->changed_flag & NTREE_CHANGED_ANY) {
+    if (tree.runtime->changed_flag & NTREE_CHANGED_ANY) {
       return true;
     }
 
@@ -1363,8 +1332,8 @@ class NodeTreeMainUpdater {
     }
 
     /* The topology hash can only be used when only topology-changing operations have been done. */
-    if (btree.runtime->changed_flag ==
-        (btree.runtime->changed_flag & (NTREE_CHANGED_LINK | NTREE_CHANGED_REMOVED_NODE))) {
+    if (tree.runtime->changed_flag ==
+        (tree.runtime->changed_flag & (NTREE_CHANGED_LINK | NTREE_CHANGED_REMOVED_NODE))) {
       if (old_topology_hash == new_topology_hash) {
         return false;
       }
@@ -1377,15 +1346,15 @@ class NodeTreeMainUpdater {
     return true;
   }
 
-  Vector find_output_sockets(const NodeTreeRef &tree)
+  Vector find_output_sockets(const bNodeTree &tree)
   {
-    Vector sockets;
-    for (const NodeRef *node : tree.nodes()) {
+    Vector sockets;
+    for (const bNode *node : tree.all_nodes()) {
       if (!this->is_output_node(*node)) {
         continue;
       }
-      for (const InputSocketRef *socket : node->inputs()) {
-        if (socket->idname() != "NodeSocketVirtual") {
+      for (const bNodeSocket *socket : node->input_sockets()) {
+        if (!STREQ(socket->idname, "NodeSocketVirtual")) {
           sockets.append(socket);
         }
       }
@@ -1393,18 +1362,17 @@ class NodeTreeMainUpdater {
     return sockets;
   }
 
-  bool is_output_node(const NodeRef &node) const
+  bool is_output_node(const bNode &node) const
   {
-    const bNode &bnode = *node.bnode();
-    if (bnode.typeinfo->nclass == NODE_CLASS_OUTPUT) {
+    if (node.typeinfo->nclass == NODE_CLASS_OUTPUT) {
       return true;
     }
-    if (bnode.type == NODE_GROUP_OUTPUT) {
+    if (node.type == NODE_GROUP_OUTPUT) {
       return true;
     }
     /* Assume node groups without output sockets are outputs. */
-    if (bnode.type == NODE_GROUP) {
-      const bNodeTree *node_group = reinterpret_cast(bnode.id);
+    if (node.type == NODE_GROUP) {
+      const bNodeTree *node_group = reinterpret_cast(node.id);
       if (node_group != nullptr &&
           node_group->runtime->runtime_flag & NTREE_RUNTIME_FLAG_HAS_MATERIAL_OUTPUT) {
         return true;
@@ -1417,10 +1385,10 @@ class NodeTreeMainUpdater {
    * Computes a hash that changes when the node tree topology connected to an output node changes.
    * Adding reroutes does not have an effect on the hash.
    */
-  uint32_t get_combined_socket_topology_hash(const NodeTreeRef &tree,
-                                             Span sockets)
+  uint32_t get_combined_socket_topology_hash(const bNodeTree &tree,
+                                             Span sockets)
   {
-    if (tree.has_link_cycles()) {
+    if (tree.has_available_link_cycle()) {
       /* Return dummy value when the link has any cycles. The algorithm below could be improved to
        * handle cycles more gracefully. */
       return 0;
@@ -1433,29 +1401,28 @@ class NodeTreeMainUpdater {
     return combined_hash;
   }
 
-  Array get_socket_topology_hashes(const NodeTreeRef &tree,
-                                             Span sockets)
+  Array get_socket_topology_hashes(const bNodeTree &tree,
+                                             Span sockets)
   {
-    BLI_assert(!tree.has_link_cycles());
-    Array> hash_by_socket_id(tree.sockets().size());
-    Stack sockets_to_check = sockets;
+    BLI_assert(!tree.has_available_link_cycle());
+    Array> hash_by_socket_id(tree.all_sockets().size());
+    Stack sockets_to_check = sockets;
 
     while (!sockets_to_check.is_empty()) {
-      const SocketRef &in_out_socket = *sockets_to_check.peek();
-      const NodeRef &node = in_out_socket.node();
+      const bNodeSocket &socket = *sockets_to_check.peek();
+      const bNode &node = socket.owner_node();
 
-      if (hash_by_socket_id[in_out_socket.id()].has_value()) {
+      if (hash_by_socket_id[socket.index_in_tree()].has_value()) {
         sockets_to_check.pop();
         /* Socket is handled already. */
         continue;
       }
 
-      if (in_out_socket.is_input()) {
+      if (socket.is_input()) {
         /* For input sockets, first compute the hashes of all linked sockets. */
-        const InputSocketRef &socket = in_out_socket.as_input();
         bool all_origins_computed = true;
-        for (const OutputSocketRef *origin_socket : socket.logically_linked_sockets()) {
-          if (!hash_by_socket_id[origin_socket->id()].has_value()) {
+        for (const bNodeSocket *origin_socket : socket.logically_linked_sockets()) {
+          if (!hash_by_socket_id[origin_socket->index_in_tree()].has_value()) {
             sockets_to_check.push(origin_socket);
             all_origins_computed = false;
           }
@@ -1465,22 +1432,21 @@ class NodeTreeMainUpdater {
         }
         /* When the hashes for the linked sockets are ready, combine them into a hash for the input
          * socket. */
-        const uint64_t socket_ptr = (uintptr_t)socket.bsocket();
+        const uint64_t socket_ptr = (uintptr_t)&socket;
         uint32_t socket_hash = noise::hash(socket_ptr, socket_ptr >> 32);
-        for (const OutputSocketRef *origin_socket : socket.logically_linked_sockets()) {
-          const uint32_t origin_socket_hash = *hash_by_socket_id[origin_socket->id()];
+        for (const bNodeSocket *origin_socket : socket.logically_linked_sockets()) {
+          const uint32_t origin_socket_hash = *hash_by_socket_id[origin_socket->index_in_tree()];
           socket_hash = noise::hash(socket_hash, origin_socket_hash);
         }
-        hash_by_socket_id[socket.id()] = socket_hash;
+        hash_by_socket_id[socket.index_in_tree()] = socket_hash;
         sockets_to_check.pop();
       }
       else {
         /* For output sockets, first compute the hashes of all available input sockets. */
-        const OutputSocketRef &socket = in_out_socket.as_output();
         bool all_available_inputs_computed = true;
-        for (const InputSocketRef *input_socket : node.inputs()) {
+        for (const bNodeSocket *input_socket : node.input_sockets()) {
           if (input_socket->is_available()) {
-            if (!hash_by_socket_id[input_socket->id()].has_value()) {
+            if (!hash_by_socket_id[input_socket->index_in_tree()].has_value()) {
               sockets_to_check.push(input_socket);
               all_available_inputs_computed = false;
             }
@@ -1491,25 +1457,25 @@ class NodeTreeMainUpdater {
         }
         /* When all input socket hashes have been computed, combine them into a hash for the output
          * socket. */
-        const uint64_t socket_ptr = (uintptr_t)socket.bsocket();
+        const uint64_t socket_ptr = (uintptr_t)&socket;
         uint32_t socket_hash = noise::hash(socket_ptr, socket_ptr >> 32);
-        for (const InputSocketRef *input_socket : node.inputs()) {
+        for (const bNodeSocket *input_socket : node.input_sockets()) {
           if (input_socket->is_available()) {
-            const uint32_t input_socket_hash = *hash_by_socket_id[input_socket->id()];
+            const uint32_t input_socket_hash = *hash_by_socket_id[input_socket->index_in_tree()];
             socket_hash = noise::hash(socket_hash, input_socket_hash);
           }
         }
         /* The Image Texture node has a special case. The behavior of the color output changes
          * depending on whether the Alpha output is linked. */
-        if (node.bnode()->type == SH_NODE_TEX_IMAGE && socket.index() == 0) {
-          BLI_assert(socket.name() == "Color");
-          const OutputSocketRef &alpha_socket = node.output(1);
-          BLI_assert(alpha_socket.name() == "Alpha");
+        if (node.type == SH_NODE_TEX_IMAGE && socket.index() == 0) {
+          BLI_assert(STREQ(socket.name, "Color"));
+          const bNodeSocket &alpha_socket = node.output_socket(1);
+          BLI_assert(STREQ(alpha_socket.name, "Alpha"));
           if (alpha_socket.is_directly_linked()) {
             socket_hash = noise::hash(socket_hash);
           }
         }
-        hash_by_socket_id[socket.id()] = socket_hash;
+        hash_by_socket_id[socket.index_in_tree()] = socket_hash;
         sockets_to_check.pop();
       }
     }
@@ -1517,7 +1483,7 @@ class NodeTreeMainUpdater {
     /* Create output array. */
     Array hashes(sockets.size());
     for (const int i : sockets.index_range()) {
-      hashes[i] = *hash_by_socket_id[sockets[i]->id()];
+      hashes[i] = *hash_by_socket_id[sockets[i]->index_in_tree()];
     }
     return hashes;
   }
@@ -1526,37 +1492,34 @@ class NodeTreeMainUpdater {
    * Returns true when any of the provided sockets changed its values. A change is detected by
    * checking the #changed_flag on connected sockets and nodes.
    */
-  bool check_if_socket_outputs_changed_based_on_flags(const NodeTreeRef &tree,
-                                                      Span sockets)
+  bool check_if_socket_outputs_changed_based_on_flags(const bNodeTree &tree,
+                                                      Span sockets)
   {
     /* Avoid visiting the same socket twice when multiple links point to the same socket. */
-    Array pushed_by_socket_id(tree.sockets().size(), false);
-    Stack sockets_to_check = sockets;
+    Array pushed_by_socket_id(tree.all_sockets().size(), false);
+    Stack sockets_to_check = sockets;
 
-    for (const SocketRef *socket : sockets) {
-      pushed_by_socket_id[socket->id()] = true;
+    for (const bNodeSocket *socket : sockets) {
+      pushed_by_socket_id[socket->index_in_tree()] = true;
     }
 
     while (!sockets_to_check.is_empty()) {
-      const SocketRef &in_out_socket = *sockets_to_check.pop();
-      const NodeRef &node = in_out_socket.node();
-      const bNode &bnode = *node.bnode();
-      const bNodeSocket &bsocket = *in_out_socket.bsocket();
-      if (bsocket.runtime->changed_flag != NTREE_CHANGED_NOTHING) {
+      const bNodeSocket &socket = *sockets_to_check.pop();
+      const bNode &node = socket.owner_node();
+      if (socket.runtime->changed_flag != NTREE_CHANGED_NOTHING) {
         return true;
       }
-      if (bnode.runtime->changed_flag != NTREE_CHANGED_NOTHING) {
-        const bool only_unused_internal_link_changed = (bnode.flag & NODE_MUTED) == 0 &&
-                                                       bnode.runtime->changed_flag ==
+      if (node.runtime->changed_flag != NTREE_CHANGED_NOTHING) {
+        const bool only_unused_internal_link_changed = !node.is_muted() &&
+                                                       node.runtime->changed_flag ==
                                                            NTREE_CHANGED_INTERNAL_LINK;
         if (!only_unused_internal_link_changed) {
           return true;
         }
       }
-      if (in_out_socket.is_input()) {
-        const InputSocketRef &socket = in_out_socket.as_input();
-        for (const OutputSocketRef *origin_socket : socket.logically_linked_sockets()) {
-          bool &pushed = pushed_by_socket_id[origin_socket->id()];
+      if (socket.is_input()) {
+        for (const bNodeSocket *origin_socket : socket.logically_linked_sockets()) {
+          bool &pushed = pushed_by_socket_id[origin_socket->index_in_tree()];
           if (!pushed) {
             sockets_to_check.push(origin_socket);
             pushed = true;
@@ -1564,10 +1527,9 @@ class NodeTreeMainUpdater {
         }
       }
       else {
-        const OutputSocketRef &socket = in_out_socket.as_output();
-        for (const InputSocketRef *input_socket : node.inputs()) {
+        for (const bNodeSocket *input_socket : node.input_sockets()) {
           if (input_socket->is_available()) {
-            bool &pushed = pushed_by_socket_id[input_socket->id()];
+            bool &pushed = pushed_by_socket_id[input_socket->index_in_tree()];
             if (!pushed) {
               sockets_to_check.push(input_socket);
               pushed = true;
@@ -1576,11 +1538,11 @@ class NodeTreeMainUpdater {
         }
         /* The Normal node has a special case, because the value stored in the first output socket
          * is used as input in the node. */
-        if (bnode.type == SH_NODE_NORMAL && socket.index() == 1) {
-          BLI_assert(socket.name() == "Dot");
-          const OutputSocketRef &normal_output = node.output(0);
-          BLI_assert(normal_output.name() == "Normal");
-          bool &pushed = pushed_by_socket_id[normal_output.id()];
+        if (node.type == SH_NODE_NORMAL && socket.index() == 1) {
+          BLI_assert(STREQ(socket.name, "Dot"));
+          const bNodeSocket &normal_output = node.output_socket(0);
+          BLI_assert(STREQ(normal_output.name, "Normal"));
+          bool &pushed = pushed_by_socket_id[normal_output.index_in_tree()];
           if (!pushed) {
             sockets_to_check.push(&normal_output);
             pushed = true;
@@ -1654,6 +1616,11 @@ void BKE_ntree_update_tag_node_removed(bNodeTree *ntree)
   add_tree_tag(ntree, NTREE_CHANGED_REMOVED_NODE);
 }
 
+void BKE_ntree_update_tag_node_reordered(bNodeTree *ntree)
+{
+  add_tree_tag(ntree, NTREE_CHANGED_ANY);
+}
+
 void BKE_ntree_update_tag_node_mute(bNodeTree *ntree, bNode *node)
 {
   add_node_tag(ntree, node, NTREE_CHANGED_NODE_PROPERTY);
diff --git a/source/blender/blenkernel/intern/object.cc b/source/blender/blenkernel/intern/object.cc
index f7436b6112c..167c6db05e2 100644
--- a/source/blender/blenkernel/intern/object.cc
+++ b/source/blender/blenkernel/intern/object.cc
@@ -145,6 +145,8 @@
 #include "atomic_ops.h"
 
 using blender::float3;
+using blender::MutableSpan;
+using blender::Span;
 
 static CLG_LogRef LOG = {"bke.object"};
 
@@ -186,7 +188,7 @@ static void object_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const in
   /* Do not copy runtime data. */
   BKE_object_runtime_reset_on_copy(ob_dst, flag);
 
-  /* We never handle usercount here for own data. */
+  /* We never handle user-count here for own data. */
   const int flag_subdata = flag | LIB_ID_CREATE_NO_USER_REFCOUNT;
 
   if (ob_src->totcol) {
@@ -243,7 +245,7 @@ static void object_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const in
 
   BLI_listbase_clear(&ob_dst->modifiers);
   BLI_listbase_clear(&ob_dst->greasepencil_modifiers);
-  /* NOTE: Also takes care of softbody and particle systems copying. */
+  /* NOTE: Also takes care of soft-body and particle systems copying. */
   BKE_object_modifier_stack_copy(ob_dst, ob_src, true, flag_subdata);
 
   BLI_listbase_clear((ListBase *)&ob_dst->drawdata);
@@ -394,7 +396,7 @@ static void object_foreach_id(ID *id, LibraryForeachIDData *data)
     BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, object->mat[i], IDWALK_CB_USER);
   }
 
-  /* Note that ob->gpd is deprecated, so no need to handle it here. */
+  /* Note that `ob->gpd` is deprecated, so no need to handle it here. */
   BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, object->instance_collection, IDWALK_CB_USER);
 
   if (object->pd) {
@@ -449,7 +451,7 @@ static void object_foreach_id(ID *id, LibraryForeachIDData *data)
 
     if (object->soft->effector_weights) {
       BKE_LIB_FOREACHID_PROCESS_IDSUPER(
-          data, object->soft->effector_weights->group, IDWALK_CB_NOP);
+          data, object->soft->effector_weights->group, IDWALK_CB_USER);
     }
   }
 }
@@ -734,9 +736,9 @@ static void object_blend_read_data(BlendDataReader *reader, ID *id)
     BLO_read_data_address(reader, &sb->shared);
     if (sb->shared == nullptr) {
       /* Link deprecated caches if they exist, so we can use them for versioning.
-       * We should only do this when sb->shared == nullptr, because those pointers
+       * We should only do this when `sb->shared == nullptr`, because those pointers
        * are always set (for compatibility with older Blenders). We mustn't link
-       * the same pointcache twice. */
+       * the same point-cache twice. */
       BKE_ptcache_blend_read_data(reader, &sb->ptcaches, &sb->pointcache, false);
     }
     else {
@@ -1139,7 +1141,7 @@ static void object_lib_override_apply_post(ID *id_dst, ID *id_src)
    * This code is a workaround this to check all point-caches from both source and destination
    * objects in parallel, and transfer those flags when it makes sense.
    *
-   * This allows to keep baked caches across liboverrides applies.
+   * This allows to keep baked caches across lib-overrides applies.
    *
    * NOTE: This is fairly hackish and weak, but so is the point-cache system as its whole. A more
    * robust solution would be e.g. to have a specific RNA entry point to deal with such cases
@@ -1168,7 +1170,7 @@ static void object_lib_override_apply_post(ID *id_dst, ID *id_src)
          point_cache_dst != nullptr;
          point_cache_dst = point_cache_dst->next,
         point_cache_src = (point_cache_src != nullptr) ? point_cache_src->next : nullptr) {
-      /* Always force updating info about caches of applied liboverrides. */
+      /* Always force updating info about caches of applied lib-overrides. */
       point_cache_dst->flag |= PTCACHE_FLAG_INFO_DIRTY;
       if (point_cache_src == nullptr || !STREQ(point_cache_dst->name, point_cache_src->name)) {
         continue;
@@ -1237,7 +1239,7 @@ IDTypeInfo IDType_ID_OB = {
     /* foreach_id */ object_foreach_id,
     /* foreach_cache */ nullptr,
     /* foreach_path */ object_foreach_path,
-    /* owner_get */ nullptr,
+    /* owner_pointer_get */ nullptr,
 
     /* blend_write */ object_blend_write,
     /* blend_read_data */ object_blend_read_data,
@@ -1298,10 +1300,10 @@ void BKE_object_free_modifiers(Object *ob, const int flag)
   while ((gp_md = (GpencilModifierData *)BLI_pophead(&ob->greasepencil_modifiers))) {
     BKE_gpencil_modifier_free_ex(gp_md, flag);
   }
-  /* particle modifiers were freed, so free the particlesystems as well */
+  /* Particle modifiers were freed, so free the particle-systems as well. */
   BKE_object_free_particlesystems(ob);
 
-  /* same for softbody */
+  /* Same for soft-body */
   BKE_object_free_softbody(ob);
 
   /* modifiers may have stored data in the DM cache */
@@ -1402,6 +1404,7 @@ bool BKE_object_supports_modifiers(const Object *ob)
 {
   return (ELEM(ob->type,
                OB_MESH,
+               OB_CURVES,
                OB_CURVES_LEGACY,
                OB_SURF,
                OB_FONT,
@@ -1445,11 +1448,11 @@ static bool object_modifier_type_copy_check(ModifierType md_type)
 }
 
 /**
- * Find a `psys` matching given `psys_src` in `ob_dst` (i.e. sharing the same ParticleSettings ID),
- * or add one, and return valid `psys` from `ob_dst`.
+ * Find a `psys` matching given `psys_src` in `ob_dst`
+ * (i.e. sharing the same #ParticleSettings ID), or add one, and return valid `psys` from `ob_dst`.
  *
  * \note Order handling is fairly weak here. This code assumes that it is called **before** the
- * modifier using the psys is actually copied, and that this copied modifier will be added at the
+ * modifier using the `psys` is actually copied, and that this copied modifier will be added at the
  * end of the stack. That way we can be sure that the particle modifier will be before the one
  * using its particle system in the stack.
  */
@@ -1664,7 +1667,7 @@ static void copy_ccg_data(Mesh *mesh_destination, Mesh *mesh_source, int layer_t
   const int layer_index = CustomData_get_layer_index(data_destination, layer_type);
   CustomData_free_layer(data_destination, layer_type, num_elements, layer_index);
   BLI_assert(!CustomData_has_layer(data_destination, layer_type));
-  CustomData_add_layer(data_destination, layer_type, CD_CALLOC, nullptr, num_elements);
+  CustomData_add_layer(data_destination, layer_type, CD_SET_DEFAULT, nullptr, num_elements);
   BLI_assert(CustomData_has_layer(data_destination, layer_type));
   CustomData_copy_layer_type_data(data_source, data_destination, layer_type, 0, 0, num_elements);
 }
@@ -2037,7 +2040,7 @@ bool BKE_object_is_mode_compat(const struct Object *ob, eObjectMode object_mode)
 
 int BKE_object_visibility(const Object *ob, const int dag_eval_mode)
 {
-  if ((ob->base_flag & BASE_VISIBLE_DEPSGRAPH) == 0) {
+  if ((ob->base_flag & BASE_ENABLED_AND_MAYBE_VISIBLE_IN_VIEWPORT) == 0) {
     return 0;
   }
 
@@ -2255,26 +2258,29 @@ Object *BKE_object_add_only_object(Main *bmain, int type, const char *name)
   return ob;
 }
 
-static Object *object_add_common(Main *bmain, ViewLayer *view_layer, int type, const char *name)
+static Object *object_add_common(
+    Main *bmain, const Scene *scene, ViewLayer *view_layer, int type, const char *name)
 {
   Object *ob = BKE_object_add_only_object(bmain, type, name);
   ob->data = BKE_object_obdata_add_from_type(bmain, type, name);
-  BKE_view_layer_base_deselect_all(view_layer);
+  BKE_view_layer_base_deselect_all(scene, view_layer);
 
   DEG_id_tag_update_ex(
       bmain, &ob->id, ID_RECALC_TRANSFORM | ID_RECALC_GEOMETRY | ID_RECALC_ANIMATION);
   return ob;
 }
 
-Object *BKE_object_add(Main *bmain, ViewLayer *view_layer, int type, const char *name)
+Object *BKE_object_add(
+    Main *bmain, Scene *scene, ViewLayer *view_layer, int type, const char *name)
 {
-  Object *ob = object_add_common(bmain, view_layer, type, name);
+  Object *ob = object_add_common(bmain, scene, view_layer, type, name);
 
   LayerCollection *layer_collection = BKE_layer_collection_get_active(view_layer);
   BKE_collection_viewlayer_object_add(bmain, view_layer, layer_collection->collection, ob);
 
   /* NOTE: There is no way to be sure that #BKE_collection_viewlayer_object_add will actually
    * manage to find a valid collection in given `view_layer` to add the new object to. */
+  BKE_view_layer_synced_ensure(scene, view_layer);
   Base *base = BKE_view_layer_base_find(view_layer, ob);
   if (base != nullptr) {
     BKE_view_layer_base_select_and_set_active(view_layer, base);
@@ -2286,17 +2292,23 @@ Object *BKE_object_add(Main *bmain, ViewLayer *view_layer, int type, const char
 Object *BKE_object_add_from(
     Main *bmain, Scene *scene, ViewLayer *view_layer, int type, const char *name, Object *ob_src)
 {
-  Object *ob = object_add_common(bmain, view_layer, type, name);
+  Object *ob = object_add_common(bmain, scene, view_layer, type, name);
   BKE_collection_object_add_from(bmain, scene, ob_src, ob);
 
+  BKE_view_layer_synced_ensure(scene, view_layer);
   Base *base = BKE_view_layer_base_find(view_layer, ob);
   BKE_view_layer_base_select_and_set_active(view_layer, base);
 
   return ob;
 }
 
-Object *BKE_object_add_for_data(
-    Main *bmain, ViewLayer *view_layer, int type, const char *name, ID *data, bool do_id_user)
+Object *BKE_object_add_for_data(Main *bmain,
+                                const Scene *scene,
+                                ViewLayer *view_layer,
+                                int type,
+                                const char *name,
+                                ID *data,
+                                bool do_id_user)
 {
   /* same as object_add_common, except we don't create new ob->data */
   Object *ob = BKE_object_add_only_object(bmain, type, name);
@@ -2305,13 +2317,14 @@ Object *BKE_object_add_for_data(
     id_us_plus(data);
   }
 
-  BKE_view_layer_base_deselect_all(view_layer);
+  BKE_view_layer_base_deselect_all(scene, view_layer);
   DEG_id_tag_update_ex(
       bmain, &ob->id, ID_RECALC_TRANSFORM | ID_RECALC_GEOMETRY | ID_RECALC_ANIMATION);
 
   LayerCollection *layer_collection = BKE_layer_collection_get_active(view_layer);
   BKE_collection_object_add(bmain, layer_collection->collection, ob);
 
+  BKE_view_layer_synced_ensure(scene, view_layer);
   Base *base = BKE_view_layer_base_find(view_layer, ob);
   BKE_view_layer_base_select_and_set_active(view_layer, base);
 
@@ -2413,7 +2426,7 @@ ParticleSystem *BKE_object_copy_particlesystem(ParticleSystem *psys, const int f
   }
 
   /* XXX(@campbellbarton): from reading existing code this seems correct but intended usage of
-   * point-cache should /w cloth should be added in 'ParticleSystem'. */
+   * point-cache should with cloth should be added in 'ParticleSystem'. */
   if (psysn->clmd) {
     psysn->clmd->point_cache = psysn->pointcache;
   }
@@ -2471,8 +2484,8 @@ void BKE_object_copy_particlesystems(Object *ob_dst, const Object *ob_src, const
 
 static void copy_object_pose(Object *obn, const Object *ob, const int flag)
 {
-  /* NOTE: need to clear obn->pose pointer first,
-   * so that BKE_pose_copy_data works (otherwise there's a crash) */
+  /* NOTE: need to clear `obn->pose` pointer first,
+   * so that #BKE_pose_copy_data works (otherwise there's a crash) */
   obn->pose = nullptr;
   BKE_pose_copy_data_ex(&obn->pose, ob->pose, flag, true); /* true = copy constraints */
 
@@ -2527,10 +2540,14 @@ Object *BKE_object_pose_armature_get(Object *ob)
   return nullptr;
 }
 
-Object *BKE_object_pose_armature_get_visible(Object *ob, ViewLayer *view_layer, View3D *v3d)
+Object *BKE_object_pose_armature_get_visible(Object *ob,
+                                             const Scene *scene,
+                                             ViewLayer *view_layer,
+                                             View3D *v3d)
 {
   Object *ob_armature = BKE_object_pose_armature_get(ob);
   if (ob_armature) {
+    BKE_view_layer_synced_ensure(scene, view_layer);
     Base *base = BKE_view_layer_base_find(view_layer, ob_armature);
     if (base) {
       if (BASE_VISIBLE(v3d, base)) {
@@ -2541,12 +2558,11 @@ Object *BKE_object_pose_armature_get_visible(Object *ob, ViewLayer *view_layer,
   return nullptr;
 }
 
-Object **BKE_object_pose_array_get_ex(ViewLayer *view_layer,
-                                      View3D *v3d,
-                                      uint *r_objects_len,
-                                      bool unique)
+Object **BKE_object_pose_array_get_ex(
+    const Scene *scene, ViewLayer *view_layer, View3D *v3d, uint *r_objects_len, bool unique)
 {
-  Object *ob_active = OBACT(view_layer);
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *ob_active = BKE_view_layer_active_object_get(view_layer);
   Object *ob_pose = BKE_object_pose_armature_get(ob_active);
   Object **objects = nullptr;
   if (ob_pose == ob_active) {
@@ -2555,7 +2571,7 @@ Object **BKE_object_pose_array_get_ex(ViewLayer *view_layer,
     ob_params.no_dup_data = unique;
 
     objects = BKE_view_layer_array_from_objects_in_mode_params(
-        view_layer, v3d, r_objects_len, &ob_params);
+        scene, view_layer, v3d, r_objects_len, &ob_params);
   }
   else if (ob_pose != nullptr) {
     *r_objects_len = 1;
@@ -2568,21 +2584,26 @@ Object **BKE_object_pose_array_get_ex(ViewLayer *view_layer,
   }
   return objects;
 }
-Object **BKE_object_pose_array_get_unique(ViewLayer *view_layer, View3D *v3d, uint *r_objects_len)
+Object **BKE_object_pose_array_get_unique(const Scene *scene,
+                                          ViewLayer *view_layer,
+                                          View3D *v3d,
+                                          uint *r_objects_len)
 {
-  return BKE_object_pose_array_get_ex(view_layer, v3d, r_objects_len, true);
+  return BKE_object_pose_array_get_ex(scene, view_layer, v3d, r_objects_len, true);
 }
-Object **BKE_object_pose_array_get(ViewLayer *view_layer, View3D *v3d, uint *r_objects_len)
+Object **BKE_object_pose_array_get(const Scene *scene,
+                                   ViewLayer *view_layer,
+                                   View3D *v3d,
+                                   uint *r_objects_len)
 {
-  return BKE_object_pose_array_get_ex(view_layer, v3d, r_objects_len, false);
+  return BKE_object_pose_array_get_ex(scene, view_layer, v3d, r_objects_len, false);
 }
 
-Base **BKE_object_pose_base_array_get_ex(ViewLayer *view_layer,
-                                         View3D *v3d,
-                                         uint *r_bases_len,
-                                         bool unique)
+Base **BKE_object_pose_base_array_get_ex(
+    const Scene *scene, ViewLayer *view_layer, View3D *v3d, uint *r_bases_len, bool unique)
 {
-  Base *base_active = BASACT(view_layer);
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Base *base_active = BKE_view_layer_active_base_get(view_layer);
   Object *ob_pose = base_active ? BKE_object_pose_armature_get(base_active->object) : nullptr;
   Base *base_pose = nullptr;
   Base **bases = nullptr;
@@ -2602,7 +2623,7 @@ Base **BKE_object_pose_base_array_get_ex(ViewLayer *view_layer,
     ob_params.no_dup_data = unique;
 
     bases = BKE_view_layer_array_from_bases_in_mode_params(
-        view_layer, v3d, r_bases_len, &ob_params);
+        scene, view_layer, v3d, r_bases_len, &ob_params);
   }
   else if (base_pose != nullptr) {
     *r_bases_len = 1;
@@ -2615,13 +2636,19 @@ Base **BKE_object_pose_base_array_get_ex(ViewLayer *view_layer,
   }
   return bases;
 }
-Base **BKE_object_pose_base_array_get_unique(ViewLayer *view_layer, View3D *v3d, uint *r_bases_len)
+Base **BKE_object_pose_base_array_get_unique(const Scene *scene,
+                                             ViewLayer *view_layer,
+                                             View3D *v3d,
+                                             uint *r_bases_len)
 {
-  return BKE_object_pose_base_array_get_ex(view_layer, v3d, r_bases_len, true);
+  return BKE_object_pose_base_array_get_ex(scene, view_layer, v3d, r_bases_len, true);
 }
-Base **BKE_object_pose_base_array_get(ViewLayer *view_layer, View3D *v3d, uint *r_bases_len)
+Base **BKE_object_pose_base_array_get(const Scene *scene,
+                                      ViewLayer *view_layer,
+                                      View3D *v3d,
+                                      uint *r_bases_len)
 {
-  return BKE_object_pose_base_array_get_ex(view_layer, v3d, r_bases_len, false);
+  return BKE_object_pose_base_array_get_ex(scene, view_layer, v3d, r_bases_len, false);
 }
 
 void BKE_object_transform_copy(Object *ob_tar, const Object *ob_src)
@@ -2889,7 +2916,7 @@ void BKE_object_rot_to_mat3(const Object *ob, float mat[3][3], bool use_drot)
     axis_angle_to_mat3(dmat, ob->drotAxis, ob->drotAngle);
   }
   else {
-    /* quats are normalized before use to eliminate scaling issues */
+    /* Quaternions are normalized before use to eliminate scaling issues. */
     float tquat[4];
 
     normalize_qt_qt(tquat, ob->quat);
@@ -2925,7 +2952,7 @@ void BKE_object_mat3_to_rot(Object *ob, float mat[3][3], bool use_compat)
       float quat[4];
       float dquat[4];
 
-      /* without drot we could apply 'mat' directly */
+      /* Without `drot` we could apply 'mat' directly. */
       mat3_normalized_to_quat(quat, mat);
       axis_angle_to_quat(dquat, ob->drotAxis, ob->drotAngle);
       invert_qt_normalized(dquat);
@@ -2938,12 +2965,12 @@ void BKE_object_mat3_to_rot(Object *ob, float mat[3][3], bool use_compat)
       float quat[4];
       float dquat[4];
 
-      /* without drot we could apply 'mat' directly */
+      /* Without `drot` we could apply 'mat' directly. */
       mat3_normalized_to_quat(quat, mat);
       eulO_to_quat(dquat, ob->drot, ob->rotmode);
       invert_qt_normalized(dquat);
       mul_qt_qtqt(quat, dquat, quat);
-      /* end drot correction */
+      /* End `drot` correction. */
 
       if (use_compat) {
         quat_to_compatible_eulO(ob->rot, ob->rot, ob->rotmode, quat);
@@ -3104,12 +3131,11 @@ static bool ob_parcurve(Object *ob, Object *par, float r_mat[4][4])
     return false;
   }
 
-  /* ctime is now a proper var setting of Curve which gets set by Animato like any other var
+  /* `ctime` is now a proper var setting of Curve which gets set by Animato like any other var
    * that's animated, but this will only work if it actually is animated.
    *
    * We divide the curve-time calculated in the previous step by the length of the path,
-   * to get a time factor, which then gets clamped to lie within 0.0 - 1.0 range.
-   */
+   * to get a time factor, which then gets clamped to lie within 0.0 - 1.0 range. */
   if (cu->pathlen) {
     ctime = cu->ctime / cu->pathlen;
   }
@@ -3188,6 +3214,7 @@ static void give_parvert(Object *par, int nr, float vec[3])
                            BKE_object_get_evaluated_mesh(par);
 
     if (me_eval) {
+      const MVert *verts = BKE_mesh_verts(me_eval);
       int count = 0;
       int numVerts = me_eval->totvert;
 
@@ -3221,14 +3248,14 @@ static void give_parvert(Object *par, int nr, float vec[3])
         /* Get the average of all verts with (original index == nr). */
         for (int i = 0; i < numVerts; i++) {
           if (index[i] == nr) {
-            add_v3_v3(vec, me_eval->mvert[i].co);
+            add_v3_v3(vec, verts[i].co);
             count++;
           }
         }
       }
       else {
         if (nr < numVerts) {
-          add_v3_v3(vec, me_eval->mvert[nr].co);
+          add_v3_v3(vec, verts[nr].co);
           count++;
         }
       }
@@ -3242,7 +3269,7 @@ static void give_parvert(Object *par, int nr, float vec[3])
       else {
         /* use first index if its out of range */
         if (me_eval->totvert) {
-          copy_v3_v3(vec, me_eval->mvert[0].co);
+          copy_v3_v3(vec, verts[0].co);
         }
       }
     }
@@ -3387,7 +3414,7 @@ static void solve_parenting(
   mul_m4_m4m4(r_obmat, tmat, locmat);
 
   if (r_originmat) {
-    /* usable originmat */
+    /* Usable `r_originmat`. */
     copy_m3_m4(r_originmat, tmat);
   }
 
@@ -4068,7 +4095,7 @@ bool BKE_object_minmax_dupli(Depsgraph *depsgraph,
     }
     else {
       Object temp_ob = blender::dna::shallow_copy(*dob->ob);
-      /* Do not modify the original boundbox. */
+      /* Do not modify the original bounding-box. */
       temp_ob.runtime.bb = nullptr;
       BKE_object_replace_data_on_shallow_copy(&temp_ob, dob->ob_data);
       const BoundBox *bb = BKE_object_boundbox_get(&temp_ob);
@@ -4121,15 +4148,15 @@ void BKE_object_foreach_display_point(Object *ob,
                                       void (*func_cb)(const float[3], void *),
                                       void *user_data)
 {
-  /* TODO: pointcloud and curves object support */
+  /* TODO: point-cloud and curves object support. */
   const Mesh *mesh_eval = BKE_object_get_evaluated_mesh(ob);
   float3 co;
 
   if (mesh_eval != nullptr) {
-    const MVert *mv = mesh_eval->mvert;
+    const MVert *verts = BKE_mesh_verts(mesh_eval);
     const int totvert = mesh_eval->totvert;
-    for (int i = 0; i < totvert; i++, mv++) {
-      mul_v3_m4v3(co, obmat, mv->co);
+    for (int i = 0; i < totvert; i++) {
+      mul_v3_m4v3(co, obmat, verts[i].co);
       func_cb(co, user_data);
     }
   }
@@ -4270,7 +4297,7 @@ void BKE_object_handle_update_ex(Depsgraph *depsgraph,
        * is evaluated on the rebuilt pose, otherwise we get incorrect poses
        * on file load */
       if (ob->pose == nullptr || (ob->pose->flag & POSE_RECALC)) {
-        /* No need to pass bmain here, we assume we do not need to rebuild DEG from here... */
+        /* No need to pass `bmain` here, we assume we do not need to rebuild DEG from here. */
         BKE_pose_rebuild(nullptr, ob, (bArmature *)ob->data, true);
       }
     }
@@ -4753,7 +4780,8 @@ bool BKE_object_shapekey_remove(Main *bmain, Object *ob, KeyBlock *kb)
       switch (ob->type) {
         case OB_MESH: {
           Mesh *mesh = (Mesh *)ob->data;
-          BKE_keyblock_convert_to_mesh(key->refkey, mesh->mvert, mesh->totvert);
+          MutableSpan verts = mesh->verts_for_write();
+          BKE_keyblock_convert_to_mesh(key->refkey, verts.data(), mesh->totvert);
           break;
         }
         case OB_CURVES_LEGACY:
@@ -5131,19 +5159,21 @@ static void obrel_list_add(LinkNode **links, Object *ob)
   ob->id.tag |= LIB_TAG_DOIT;
 }
 
-LinkNode *BKE_object_relational_superset(struct ViewLayer *view_layer,
+LinkNode *BKE_object_relational_superset(const Scene *scene,
+                                         struct ViewLayer *view_layer,
                                          eObjectSet objectSet,
                                          eObRelationTypes includeFilter)
 {
   LinkNode *links = nullptr;
 
   /* Remove markers from all objects */
-  LISTBASE_FOREACH (Base *, base, &view_layer->object_bases) {
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  LISTBASE_FOREACH (Base *, base, BKE_view_layer_object_bases_get(view_layer)) {
     base->object->id.tag &= ~LIB_TAG_DOIT;
   }
 
   /* iterate over all selected and visible objects */
-  LISTBASE_FOREACH (Base *, base, &view_layer->object_bases) {
+  LISTBASE_FOREACH (Base *, base, BKE_view_layer_object_bases_get(view_layer)) {
     if (objectSet == OB_SET_ALL) {
       /* as we get all anyways just add it */
       Object *ob = base->object;
@@ -5179,7 +5209,7 @@ LinkNode *BKE_object_relational_superset(struct ViewLayer *view_layer,
 
         /* child relationship */
         if (includeFilter & (OB_REL_CHILDREN | OB_REL_CHILDREN_RECURSIVE)) {
-          LISTBASE_FOREACH (Base *, local_base, &view_layer->object_bases) {
+          LISTBASE_FOREACH (Base *, local_base, BKE_view_layer_object_bases_get(view_layer)) {
             if (BASE_EDITABLE(((View3D *)nullptr), local_base)) {
 
               Object *child = local_base->object;
@@ -5249,32 +5279,31 @@ KDTree_3d *BKE_object_as_kdtree(Object *ob, int *r_tot)
       const int *index;
 
       if (me_eval && (index = (const int *)CustomData_get_layer(&me_eval->vdata, CD_ORIGINDEX))) {
-        MVert *mvert = me_eval->mvert;
-        uint totvert = me_eval->totvert;
+        const Span verts = me->verts();
 
         /* Tree over-allocates in case where some verts have #ORIGINDEX_NONE. */
         tot = 0;
-        tree = BLI_kdtree_3d_new(totvert);
+        tree = BLI_kdtree_3d_new(verts.size());
 
         /* We don't how many verts from the DM we can use. */
-        for (i = 0; i < totvert; i++) {
+        for (i = 0; i < verts.size(); i++) {
           if (index[i] != ORIGINDEX_NONE) {
             float co[3];
-            mul_v3_m4v3(co, ob->obmat, mvert[i].co);
+            mul_v3_m4v3(co, ob->obmat, verts[i].co);
             BLI_kdtree_3d_insert(tree, index[i], co);
             tot++;
           }
         }
       }
       else {
-        MVert *mvert = me->mvert;
+        const Span verts = me->verts();
 
-        tot = me->totvert;
+        tot = verts.size();
         tree = BLI_kdtree_3d_new(tot);
 
         for (i = 0; i < tot; i++) {
           float co[3];
-          mul_v3_m4v3(co, ob->obmat, mvert[i].co);
+          mul_v3_m4v3(co, ob->obmat, verts[i].co);
           BLI_kdtree_3d_insert(tree, i, co);
         }
       }
@@ -5419,8 +5448,7 @@ bool BKE_object_modifier_update_subframe(Depsgraph *depsgraph,
           depsgraph, scene, ob->track, false, recursion, frame, type);
     }
 
-    /* skip subframe if object is parented
-     * to vertex of a dynamic paint canvas */
+    /* Skip sub-frame if object is parented to vertex of a dynamic paint canvas. */
     if (no_update && (ELEM(ob->partype, PARVERT1, PARVERT3))) {
       return false;
     }
@@ -5451,8 +5479,7 @@ bool BKE_object_modifier_update_subframe(Depsgraph *depsgraph,
   if (update_mesh) {
     BKE_animsys_evaluate_animdata(
         &ob->id, ob->adt, &anim_eval_context, ADT_RECALC_ANIM, flush_to_original);
-    /* ignore cache clear during subframe updates
-     * to not mess up cache validity */
+    /* Ignore cache clear during sub-frame updates to not mess up cache validity. */
     object_cacheIgnoreClear(ob, 1);
     BKE_object_handle_update(depsgraph, scene, ob);
     object_cacheIgnoreClear(ob, 0);
diff --git a/source/blender/blenkernel/intern/object_deform.c b/source/blender/blenkernel/intern/object_deform.c
index 310ec7678bd..1fe5d7aa0e7 100644
--- a/source/blender/blenkernel/intern/object_deform.c
+++ b/source/blender/blenkernel/intern/object_deform.c
@@ -114,9 +114,7 @@ bDeformGroup *BKE_object_defgroup_add(Object *ob)
 MDeformVert *BKE_object_defgroup_data_create(ID *id)
 {
   if (GS(id->name) == ID_ME) {
-    Mesh *me = (Mesh *)id;
-    me->dvert = CustomData_add_layer(&me->vdata, CD_MDEFORMVERT, CD_CALLOC, NULL, me->totvert);
-    return me->dvert;
+    return BKE_mesh_deform_verts_for_write((Mesh *)id);
   }
   if (GS(id->name) == ID_LT) {
     Lattice *lt = (Lattice *)id;
@@ -164,12 +162,12 @@ bool BKE_object_defgroup_clear(Object *ob, bDeformGroup *dg, const bool use_sele
       }
     }
     else {
-      if (me->dvert) {
-        MVert *mv;
+      if (BKE_mesh_deform_verts(me)) {
+        const MVert *mv;
         int i;
 
-        mv = me->mvert;
-        dv = me->dvert;
+        mv = BKE_mesh_verts(me);
+        dv = BKE_mesh_deform_verts_for_write(me);
 
         for (i = 0; i < me->totvert; i++, mv++, dv++) {
           if (dv->dw && (!use_selection || (mv->flag & SELECT))) {
@@ -264,7 +262,6 @@ static void object_defgroup_remove_common(Object *ob, bDeformGroup *dg, const in
     if (ob->type == OB_MESH) {
       Mesh *me = ob->data;
       CustomData_free_layer_active(&me->vdata, CD_MDEFORMVERT, me->totvert);
-      me->dvert = NULL;
     }
     else if (ob->type == OB_LATTICE) {
       Lattice *lt = object_defgroup_lattice_get((ID *)(ob->data));
@@ -412,7 +409,6 @@ void BKE_object_defgroup_remove_all_ex(struct Object *ob, bool only_unlocked)
     if (ob->type == OB_MESH) {
       Mesh *me = ob->data;
       CustomData_free_layer_active(&me->vdata, CD_MDEFORMVERT, me->totvert);
-      me->dvert = NULL;
     }
     else if (ob->type == OB_LATTICE) {
       Lattice *lt = object_defgroup_lattice_get((ID *)(ob->data));
@@ -501,7 +497,7 @@ bool BKE_object_defgroup_array_get(ID *id, MDeformVert **dvert_arr, int *dvert_t
     switch (GS(id->name)) {
       case ID_ME: {
         Mesh *me = (Mesh *)id;
-        *dvert_arr = me->dvert;
+        *dvert_arr = BKE_mesh_deform_verts_for_write(me);
         *dvert_tot = me->totvert;
         return true;
       }
diff --git a/source/blender/blenkernel/intern/object_dupli.cc b/source/blender/blenkernel/intern/object_dupli.cc
index 407a2c8955c..6db1c864918 100644
--- a/source/blender/blenkernel/intern/object_dupli.cc
+++ b/source/blender/blenkernel/intern/object_dupli.cc
@@ -29,6 +29,7 @@
 #include "DNA_pointcloud_types.h"
 #include "DNA_scene_types.h"
 #include "DNA_vfont_types.h"
+#include "DNA_volume_types.h"
 
 #include "BKE_collection.h"
 #include "BKE_duplilist.h"
@@ -164,10 +165,8 @@ static bool copy_dupli_context(
  *
  * \param mat: is transform of the object relative to current context (including #Object.obmat).
  */
-static DupliObject *make_dupli(const DupliContext *ctx,
-                               Object *ob,
-                               const float mat[4][4],
-                               int index)
+static DupliObject *make_dupli(
+    const DupliContext *ctx, Object *ob, const ID *object_data, const float mat[4][4], int index)
 {
   DupliObject *dob;
   int i;
@@ -182,7 +181,7 @@ static DupliObject *make_dupli(const DupliContext *ctx,
   }
 
   dob->ob = ob;
-  dob->ob_data = (ID *)ob->data;
+  dob->ob_data = const_cast(object_data);
   mul_m4_m4m4(dob->mat, (float(*)[4])ctx->space_mat, mat);
   dob->type = ctx->gen->type;
 
@@ -202,7 +201,7 @@ static DupliObject *make_dupli(const DupliContext *ctx,
   /* Meta-balls never draw in duplis, they are instead merged into one by the basis
    * meta-ball outside of the group. this does mean that if that meta-ball is not in the
    * scene, they will not show up at all, limitation that should be solved once. */
-  if (ob->type == OB_MBALL) {
+  if (object_data && GS(object_data->name) == ID_MB) {
     dob->no_draw = true;
   }
 
@@ -226,6 +225,14 @@ static DupliObject *make_dupli(const DupliContext *ctx,
   return dob;
 }
 
+static DupliObject *make_dupli(const DupliContext *ctx,
+                               Object *ob,
+                               const float mat[4][4],
+                               int index)
+{
+  return make_dupli(ctx, ob, static_cast(ob->data), mat, index);
+}
+
 /**
  * Recursive dupli-objects.
  *
@@ -621,7 +628,7 @@ static void make_duplis_verts(const DupliContext *ctx)
     VertexDupliData_Mesh vdd{};
     vdd.params = vdd_params;
     vdd.totvert = me_eval->totvert;
-    vdd.mvert = me_eval->mvert;
+    vdd.mvert = me_eval->verts().data();
     vdd.vert_normals = BKE_mesh_vertex_normals_ensure(me_eval);
     vdd.orco = (const float(*)[3])CustomData_get_layer(&me_eval->vdata, CD_ORCO);
 
@@ -777,28 +784,24 @@ static void make_duplis_geometry_set_impl(const DupliContext *ctx,
   int component_index = 0;
   if (ctx->object->type != OB_MESH || geometry_set_is_instance) {
     if (const Mesh *mesh = geometry_set.get_mesh_for_read()) {
-      DupliObject *dupli = make_dupli(ctx, ctx->object, parent_transform, component_index++);
-      dupli->ob_data = (ID *)mesh;
+      make_dupli(ctx, ctx->object, &mesh->id, parent_transform, component_index++);
     }
   }
   if (ctx->object->type != OB_VOLUME || geometry_set_is_instance) {
     if (const Volume *volume = geometry_set.get_volume_for_read()) {
-      DupliObject *dupli = make_dupli(ctx, ctx->object, parent_transform, component_index++);
-      dupli->ob_data = (ID *)volume;
+      make_dupli(ctx, ctx->object, &volume->id, parent_transform, component_index++);
     }
   }
   if (!ELEM(ctx->object->type, OB_CURVES_LEGACY, OB_FONT, OB_CURVES) || geometry_set_is_instance) {
     if (const CurveComponent *component = geometry_set.get_component_for_read()) {
       if (const Curve *curve = component->get_curve_for_render()) {
-        DupliObject *dupli = make_dupli(ctx, ctx->object, parent_transform, component_index++);
-        dupli->ob_data = (ID *)curve;
+        make_dupli(ctx, ctx->object, &curve->id, parent_transform, component_index++);
       }
     }
   }
   if (ctx->object->type != OB_POINTCLOUD || geometry_set_is_instance) {
     if (const PointCloud *pointcloud = geometry_set.get_pointcloud_for_read()) {
-      DupliObject *dupli = make_dupli(ctx, ctx->object, parent_transform, component_index++);
-      dupli->ob_data = (ID *)pointcloud;
+      make_dupli(ctx, ctx->object, &pointcloud->id, parent_transform, component_index++);
     }
   }
   const bool creates_duplis_for_components = component_index >= 1;
@@ -1175,9 +1178,9 @@ static void make_duplis_faces(const DupliContext *ctx)
     FaceDupliData_Mesh fdd{};
     fdd.params = fdd_params;
     fdd.totface = me_eval->totpoly;
-    fdd.mpoly = me_eval->mpoly;
-    fdd.mloop = me_eval->mloop;
-    fdd.mvert = me_eval->mvert;
+    fdd.mpoly = me_eval->polys().data();
+    fdd.mloop = me_eval->loops().data();
+    fdd.mvert = me_eval->verts().data();
     fdd.mloopuv = (uv_idx != -1) ? (const MLoopUV *)CustomData_get_layer_n(
                                        &me_eval->ldata, CD_MLOOPUV, uv_idx) :
                                    nullptr;
@@ -1560,6 +1563,13 @@ static const DupliGenerator *get_dupli_generator(const DupliContext *ctx)
     return nullptr;
   }
 
+  /* Metaball objects can't create instances, but the dupli system is used to "instance" their
+   * evaluated mesh to render engines. We need to exit early to avoid recursively instancing the
+   * evaluated metaball mesh on metaball instances that already contribute to the basis. */
+  if (ctx->object->type == OB_MBALL && ctx->level > 0) {
+    return nullptr;
+  }
+
   /* Should the dupli's be generated for this object? - Respect restrict flags. */
   if (DEG_get_mode(ctx->depsgraph) == DAG_EVAL_RENDER ? (visibility_flag & OB_HIDE_RENDER) :
                                                         (visibility_flag & OB_HIDE_VIEWPORT)) {
diff --git a/source/blender/blenkernel/intern/object_update.c b/source/blender/blenkernel/intern/object_update.c
index 8ff02c7e698..91170060fee 100644
--- a/source/blender/blenkernel/intern/object_update.c
+++ b/source/blender/blenkernel/intern/object_update.c
@@ -110,7 +110,6 @@ void BKE_object_eval_constraints(Depsgraph *depsgraph, Scene *scene, Object *ob)
    * - post (i.e. BKE_constraints_clear_evalob)
    *
    * Not sure why, this is from Joshua - sergey
-   *
    */
   cob = BKE_constraints_make_evalob(depsgraph, scene, ob, NULL, CONSTRAINT_OBTYPE_OBJECT);
   BKE_constraints_solve(depsgraph, &ob->constraints, cob, ctime);
@@ -149,10 +148,6 @@ void BKE_object_handle_data_update(Depsgraph *depsgraph, Scene *scene, Object *o
       cddata_masks.pmask |= CD_MASK_PROP_ALL;
       cddata_masks.lmask |= CD_MASK_PROP_ALL;
 
-      /* Also copy over normal layers to avoid recomputation. */
-      cddata_masks.pmask |= CD_MASK_NORMAL;
-      cddata_masks.vmask |= CD_MASK_NORMAL;
-
       /* Make sure Freestyle edge/face marks appear in DM for render (see T40315).
        * Due to Line Art implementation, edge marks should also be shown in viewport. */
 #ifdef WITH_FREESTYLE
@@ -173,7 +168,7 @@ void BKE_object_handle_data_update(Depsgraph *depsgraph, Scene *scene, Object *o
       break;
 
     case OB_MBALL:
-      BKE_displist_make_mball(depsgraph, scene, ob);
+      BKE_mball_data_update(depsgraph, scene, ob);
       break;
 
     case OB_CURVES_LEGACY:
@@ -285,45 +280,45 @@ void BKE_object_eval_uber_transform(Depsgraph *UNUSED(depsgraph), Object *UNUSED
 {
 }
 
-void BKE_object_data_batch_cache_dirty_tag(ID *object_data)
+void BKE_object_batch_cache_dirty_tag(Object *ob)
 {
-  switch (GS(object_data->name)) {
-    case ID_ME:
-      BKE_mesh_batch_cache_dirty_tag((struct Mesh *)object_data, BKE_MESH_BATCH_DIRTY_ALL);
+  switch (ob->type) {
+    case OB_MESH:
+      BKE_mesh_batch_cache_dirty_tag((struct Mesh *)ob->data, BKE_MESH_BATCH_DIRTY_ALL);
       break;
-    case ID_LT:
-      BKE_lattice_batch_cache_dirty_tag((struct Lattice *)object_data,
-                                        BKE_LATTICE_BATCH_DIRTY_ALL);
+    case OB_LATTICE:
+      BKE_lattice_batch_cache_dirty_tag((struct Lattice *)ob->data, BKE_LATTICE_BATCH_DIRTY_ALL);
       break;
-    case ID_CU_LEGACY:
-      BKE_curve_batch_cache_dirty_tag((struct Curve *)object_data, BKE_CURVE_BATCH_DIRTY_ALL);
+    case OB_CURVES_LEGACY:
+      BKE_curve_batch_cache_dirty_tag((struct Curve *)ob->data, BKE_CURVE_BATCH_DIRTY_ALL);
       break;
-    case ID_MB:
-      BKE_mball_batch_cache_dirty_tag((struct MetaBall *)object_data, BKE_MBALL_BATCH_DIRTY_ALL);
+    case OB_MBALL: {
+      /* This function is currently called on original objects, so to properly
+       * clear the actual displayed geometry, we have to tag the evaluated mesh. */
+      Mesh *mesh = BKE_object_get_evaluated_mesh_no_subsurf(ob);
+      if (mesh) {
+        BKE_mesh_batch_cache_dirty_tag(mesh, BKE_MESH_BATCH_DIRTY_ALL);
+      }
       break;
-    case ID_GD:
-      BKE_gpencil_batch_cache_dirty_tag((struct bGPdata *)object_data);
+    }
+    case OB_GPENCIL:
+      BKE_gpencil_batch_cache_dirty_tag((struct bGPdata *)ob->data);
       break;
-    case ID_CV:
-      BKE_curves_batch_cache_dirty_tag((struct Curves *)object_data, BKE_CURVES_BATCH_DIRTY_ALL);
+    case OB_CURVES:
+      BKE_curves_batch_cache_dirty_tag((struct Curves *)ob->data, BKE_CURVES_BATCH_DIRTY_ALL);
       break;
-    case ID_PT:
-      BKE_pointcloud_batch_cache_dirty_tag((struct PointCloud *)object_data,
+    case OB_POINTCLOUD:
+      BKE_pointcloud_batch_cache_dirty_tag((struct PointCloud *)ob->data,
                                            BKE_POINTCLOUD_BATCH_DIRTY_ALL);
       break;
-    case ID_VO:
-      BKE_volume_batch_cache_dirty_tag((struct Volume *)object_data, BKE_VOLUME_BATCH_DIRTY_ALL);
+    case OB_VOLUME:
+      BKE_volume_batch_cache_dirty_tag((struct Volume *)ob->data, BKE_VOLUME_BATCH_DIRTY_ALL);
       break;
     default:
       break;
   }
 }
 
-void BKE_object_batch_cache_dirty_tag(Object *ob)
-{
-  BKE_object_data_batch_cache_dirty_tag(ob->data);
-}
-
 void BKE_object_eval_uber_data(Depsgraph *depsgraph, Scene *scene, Object *ob)
 {
   DEG_debug_print_eval(depsgraph, __func__, ob->id.name, ob);
@@ -412,10 +407,10 @@ void BKE_object_eval_eval_base_flags(Depsgraph *depsgraph,
    * assumed viewport visibility. Select-ability does not matter here. */
   if (DEG_get_mode(depsgraph) == DAG_EVAL_RENDER) {
     if (base->flag & BASE_ENABLED_RENDER) {
-      base->flag |= BASE_VISIBLE_DEPSGRAPH;
+      base->flag |= BASE_ENABLED_AND_MAYBE_VISIBLE_IN_VIEWPORT;
     }
     else {
-      base->flag &= ~BASE_VISIBLE_DEPSGRAPH;
+      base->flag &= ~BASE_ENABLED_AND_MAYBE_VISIBLE_IN_VIEWPORT;
     }
   }
 
diff --git a/source/blender/blenkernel/intern/ocean.c b/source/blender/blenkernel/intern/ocean.c
index dec9a594938..cd1f24fee37 100644
--- a/source/blender/blenkernel/intern/ocean.c
+++ b/source/blender/blenkernel/intern/ocean.c
@@ -1385,9 +1385,8 @@ void BKE_ocean_bake(struct Ocean *o,
                     void (*update_cb)(void *, float progress, int *cancel),
                     void *update_cb_data)
 {
-  /* NOTE(campbell): some of these values remain uninitialized unless certain options
-   * are enabled, take care that BKE_ocean_eval_ij() initializes a member
-   * before use. */
+  /* NOTE(@campbellbarton): some of these values remain uninitialized unless certain options
+   * are enabled, take care that #BKE_ocean_eval_ij() initializes a member before use. */
   OceanResult ocr;
 
   ImageFormatData imf = {0};
@@ -1441,7 +1440,7 @@ void BKE_ocean_bake(struct Ocean *o,
         rgb_to_rgba_unit_alpha(&ibuf_disp->rect_float[4 * (res_x * y + x)], ocr.disp);
 
         if (o->_do_jacobian) {
-          /* TODO(campbell): cleanup unused code. */
+          /* TODO(@campbellbarton): cleanup unused code. */
 
           float /* r, */ /* UNUSED */ pr = 0.0f, foam_result;
           float neg_disp, neg_eplus;
diff --git a/source/blender/blenkernel/intern/outliner_treehash.c b/source/blender/blenkernel/intern/outliner_treehash.c
deleted file mode 100644
index 03c327bec2f..00000000000
--- a/source/blender/blenkernel/intern/outliner_treehash.c
+++ /dev/null
@@ -1,238 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-
-/** \file
- * \ingroup bke
- *
- * Tree hash for the outliner space.
- */
-
-#include 
-#include 
-
-#include "BLI_ghash.h"
-#include "BLI_mempool.h"
-#include "BLI_utildefines.h"
-
-#include "DNA_outliner_types.h"
-
-#include "BKE_outliner_treehash.h"
-
-#include "MEM_guardedalloc.h"
-
-typedef struct TseGroup {
-  TreeStoreElem **elems;
-  int lastused;
-  int size;
-  int allocated;
-} TseGroup;
-
-/* Allocate structure for TreeStoreElements;
- * Most of elements in treestore have no duplicates,
- * so there is no need to preallocate memory for more than one pointer */
-static TseGroup *tse_group_create(void)
-{
-  TseGroup *tse_group = MEM_mallocN(sizeof(TseGroup), "TseGroup");
-  tse_group->elems = MEM_mallocN(sizeof(TreeStoreElem *), "TseGroupElems");
-  tse_group->size = 0;
-  tse_group->allocated = 1;
-  tse_group->lastused = 0;
-  return tse_group;
-}
-
-static void tse_group_add_element(TseGroup *tse_group, TreeStoreElem *elem)
-{
-  if (UNLIKELY(tse_group->size == tse_group->allocated)) {
-    tse_group->allocated *= 2;
-    tse_group->elems = MEM_reallocN(tse_group->elems,
-                                    sizeof(TreeStoreElem *) * tse_group->allocated);
-  }
-  tse_group->elems[tse_group->size] = elem;
-  tse_group->size++;
-}
-
-static void tse_group_remove_element(TseGroup *tse_group, TreeStoreElem *elem)
-{
-  int min_allocated = MAX2(1, tse_group->allocated / 2);
-  BLI_assert(tse_group->allocated == 1 || (tse_group->allocated % 2) == 0);
-
-  tse_group->size--;
-  BLI_assert(tse_group->size >= 0);
-  for (int i = 0; i < tse_group->size; i++) {
-    if (tse_group->elems[i] == elem) {
-      memcpy(tse_group->elems[i],
-             tse_group->elems[i + 1],
-             (tse_group->size - (i + 1)) * sizeof(TreeStoreElem *));
-      break;
-    }
-  }
-
-  if (UNLIKELY(tse_group->size > 0 && tse_group->size <= min_allocated)) {
-    tse_group->allocated = min_allocated;
-    tse_group->elems = MEM_reallocN(tse_group->elems,
-                                    sizeof(TreeStoreElem *) * tse_group->allocated);
-  }
-}
-
-static void tse_group_free(TseGroup *tse_group)
-{
-  MEM_freeN(tse_group->elems);
-  MEM_freeN(tse_group);
-}
-
-static unsigned int tse_hash(const void *ptr)
-{
-  const TreeStoreElem *tse = ptr;
-  union {
-    short h_pair[2];
-    unsigned int u_int;
-  } hash;
-
-  BLI_assert((tse->type != TSE_SOME_ID) || !tse->nr);
-
-  hash.h_pair[0] = tse->type;
-  hash.h_pair[1] = tse->nr;
-
-  hash.u_int ^= BLI_ghashutil_ptrhash(tse->id);
-
-  return hash.u_int;
-}
-
-static bool tse_cmp(const void *a, const void *b)
-{
-  const TreeStoreElem *tse_a = a;
-  const TreeStoreElem *tse_b = b;
-  return tse_a->type != tse_b->type || tse_a->nr != tse_b->nr || tse_a->id != tse_b->id;
-}
-
-static void fill_treehash(void *treehash, BLI_mempool *treestore)
-{
-  TreeStoreElem *tselem;
-  BLI_mempool_iter iter;
-  BLI_mempool_iternew(treestore, &iter);
-
-  BLI_assert(treehash);
-
-  while ((tselem = BLI_mempool_iterstep(&iter))) {
-    BKE_outliner_treehash_add_element(treehash, tselem);
-  }
-}
-
-void *BKE_outliner_treehash_create_from_treestore(BLI_mempool *treestore)
-{
-  GHash *treehash = BLI_ghash_new_ex(tse_hash, tse_cmp, "treehash", BLI_mempool_len(treestore));
-  fill_treehash(treehash, treestore);
-  return treehash;
-}
-
-static void free_treehash_group(void *key)
-{
-  tse_group_free(key);
-}
-
-void BKE_outliner_treehash_clear_used(void *treehash)
-{
-  GHashIterator gh_iter;
-
-  GHASH_ITER (gh_iter, treehash) {
-    TseGroup *group = BLI_ghashIterator_getValue(&gh_iter);
-    group->lastused = 0;
-  }
-}
-
-void *BKE_outliner_treehash_rebuild_from_treestore(void *treehash, BLI_mempool *treestore)
-{
-  BLI_assert(treehash);
-
-  BLI_ghash_clear_ex(treehash, NULL, free_treehash_group, BLI_mempool_len(treestore));
-  fill_treehash(treehash, treestore);
-  return treehash;
-}
-
-void BKE_outliner_treehash_add_element(void *treehash, TreeStoreElem *elem)
-{
-  TseGroup *group;
-  void **val_p;
-
-  if (!BLI_ghash_ensure_p(treehash, elem, &val_p)) {
-    *val_p = tse_group_create();
-  }
-  group = *val_p;
-  group->lastused = 0;
-  tse_group_add_element(group, elem);
-}
-
-void BKE_outliner_treehash_remove_element(void *treehash, TreeStoreElem *elem)
-{
-  TseGroup *group = BLI_ghash_lookup(treehash, elem);
-
-  BLI_assert(group != NULL);
-  if (group->size <= 1) {
-    /* one element -> remove group completely */
-    BLI_ghash_remove(treehash, elem, NULL, free_treehash_group);
-  }
-  else {
-    tse_group_remove_element(group, elem);
-  }
-}
-
-static TseGroup *BKE_outliner_treehash_lookup_group(GHash *th, short type, short nr, struct ID *id)
-{
-  TreeStoreElem tse_template;
-  tse_template.type = type;
-  tse_template.nr = (type == TSE_SOME_ID) ? 0 : nr; /* we're picky! :) */
-  tse_template.id = id;
-
-  BLI_assert(th);
-
-  return BLI_ghash_lookup(th, &tse_template);
-}
-
-TreeStoreElem *BKE_outliner_treehash_lookup_unused(void *treehash,
-                                                   short type,
-                                                   short nr,
-                                                   struct ID *id)
-{
-  TseGroup *group;
-
-  BLI_assert(treehash);
-
-  group = BKE_outliner_treehash_lookup_group(treehash, type, nr, id);
-  if (group) {
-    /* Find unused element, with optimization to start from previously
-     * found element assuming we do repeated lookups. */
-    int size = group->size;
-    int offset = group->lastused;
-
-    for (int i = 0; i < size; i++, offset++) {
-      if (offset >= size) {
-        offset = 0;
-      }
-
-      if (!group->elems[offset]->used) {
-        group->lastused = offset;
-        return group->elems[offset];
-      }
-    }
-  }
-  return NULL;
-}
-
-TreeStoreElem *BKE_outliner_treehash_lookup_any(void *treehash,
-                                                short type,
-                                                short nr,
-                                                struct ID *id)
-{
-  TseGroup *group;
-
-  BLI_assert(treehash);
-
-  group = BKE_outliner_treehash_lookup_group(treehash, type, nr, id);
-  return group ? group->elems[0] : NULL;
-}
-
-void BKE_outliner_treehash_free(void *treehash)
-{
-  BLI_assert(treehash);
-
-  BLI_ghash_free(treehash, NULL, free_treehash_group);
-}
diff --git a/source/blender/blenkernel/intern/outliner_treehash.cc b/source/blender/blenkernel/intern/outliner_treehash.cc
new file mode 100644
index 00000000000..3f66f6bb745
--- /dev/null
+++ b/source/blender/blenkernel/intern/outliner_treehash.cc
@@ -0,0 +1,209 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/** \file
+ * \ingroup bke
+ *
+ * Tree hash for the outliner space.
+ */
+
+#include 
+#include 
+
+#include "BLI_mempool.h"
+#include "BLI_utildefines.h"
+#include "BLI_vector.hh"
+
+#include "DNA_outliner_types.h"
+
+#include "BKE_outliner_treehash.hh"
+
+#include "MEM_guardedalloc.h"
+
+namespace blender::bke::outliner::treehash {
+
+/* -------------------------------------------------------------------- */
+/** \name #TseGroup
+ * \{ */
+
+class TseGroup {
+ public:
+  blender::Vector elems;
+  /* Index of last used #TreeStoreElem item, to speed up search for another one. */
+  int lastused = 0;
+  /* Counter used to reduce the amount of 'rests' of `lastused` index, otherwise search for unused
+   * item is exponential and becomes critically slow when there are a lot of items in the group. */
+  int lastused_reset_count = -1;
+
+ public:
+  void add_element(TreeStoreElem &elem);
+  void remove_element(TreeStoreElem &elem);
+};
+
+/* Only allow reset of #TseGroup.lastused counter to 0 once every 1k search. */
+#define TSEGROUP_LASTUSED_RESET_VALUE 10000
+
+void TseGroup::add_element(TreeStoreElem &elem)
+{
+  const int64_t idx = elems.append_and_get_index(&elem);
+  lastused = idx;
+}
+
+void TseGroup::remove_element(TreeStoreElem &elem)
+{
+  const int64_t idx = elems.first_index_of(&elem);
+  elems.remove(idx);
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name #TreeStoreElemKey
+ * \{ */
+
+TreeStoreElemKey::TreeStoreElemKey(const TreeStoreElem &elem)
+    : id(elem.id), type(elem.type), nr(elem.nr)
+{
+}
+
+TreeStoreElemKey::TreeStoreElemKey(ID *id, short type, short nr) : id(id), type(type), nr(nr)
+{
+}
+
+uint64_t TreeStoreElemKey::hash() const
+{
+  return get_default_hash_3(id, type, nr);
+}
+
+bool operator==(const TreeStoreElemKey &a, const TreeStoreElemKey &b)
+{
+  return (a.id == b.id) && (a.type == b.type) && (a.nr == b.nr);
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name #TreeHash
+ * \{ */
+
+TreeHash::~TreeHash() = default;
+
+std::unique_ptr TreeHash::create_from_treestore(BLI_mempool &treestore)
+{
+  /* Can't use `make_unique()` here because of private constructor. */
+  std::unique_ptr tree_hash{new TreeHash()};
+  tree_hash->fill_treehash(treestore);
+
+  return tree_hash;
+}
+
+void TreeHash::fill_treehash(BLI_mempool &treestore)
+{
+  TreeStoreElem *tselem;
+  BLI_mempool_iter iter;
+  BLI_mempool_iternew(&treestore, &iter);
+
+  while ((tselem = static_cast(BLI_mempool_iterstep(&iter)))) {
+    add_element(*tselem);
+  }
+}
+
+void TreeHash::clear_used()
+{
+  for (auto &group : elem_groups_.values()) {
+    group->lastused = 0;
+    group->lastused_reset_count = 0;
+  }
+}
+
+void TreeHash::rebuild_from_treestore(BLI_mempool &treestore)
+{
+  elem_groups_.clear();
+  fill_treehash(treestore);
+}
+
+void TreeHash::add_element(TreeStoreElem &elem)
+{
+  std::unique_ptr &group = elem_groups_.lookup_or_add_cb(
+      TreeStoreElemKey(elem), []() { return std::make_unique(); });
+  group->add_element(elem);
+}
+
+void TreeHash::remove_element(TreeStoreElem &elem)
+{
+  TseGroup *group = lookup_group(elem);
+  BLI_assert(group != nullptr);
+
+  if (group->elems.size() <= 1) {
+    /* One element -> remove group completely. */
+    elem_groups_.remove(TreeStoreElemKey(elem));
+  }
+  else {
+    group->remove_element(elem);
+  }
+}
+
+TseGroup *TreeHash::lookup_group(const TreeStoreElemKey &key) const
+{
+  auto *group = elem_groups_.lookup_ptr(key);
+  if (group) {
+    return group->get();
+  }
+  return nullptr;
+}
+
+TseGroup *TreeHash::lookup_group(const TreeStoreElem &key_elem) const
+{
+  return lookup_group(TreeStoreElemKey(key_elem));
+}
+
+TseGroup *TreeHash::lookup_group(const short type, const short nr, ID *id) const
+{
+  TreeStoreElemKey key(id, type, nr);
+  if (type == TSE_SOME_ID) {
+    key.nr = 0; /* we're picky! :) */
+  }
+  return lookup_group(key);
+}
+
+TreeStoreElem *TreeHash::lookup_unused(const short type, const short nr, ID *id) const
+{
+  TseGroup *group = lookup_group(type, nr, id);
+  if (!group) {
+    return nullptr;
+  }
+
+  /* Find unused element, with optimization to start from previously
+   * found element assuming we do repeated lookups. */
+  const int size = group->elems.size();
+  int offset = group->lastused;
+
+  for (int i = 0; i < size; i++, offset++) {
+    /* Once at the end of the array of items, in most cases it just means that all items are
+     * used, so only check the whole array once every TSEGROUP_LASTUSED_RESET_VALUE times. */
+    if (offset >= size) {
+      if (LIKELY(group->lastused_reset_count <= TSEGROUP_LASTUSED_RESET_VALUE)) {
+        group->lastused_reset_count++;
+        group->lastused = group->elems.size() - 1;
+        break;
+      }
+      group->lastused_reset_count = 0;
+      offset = 0;
+    }
+
+    if (!group->elems[offset]->used) {
+      group->lastused = offset;
+      return group->elems[offset];
+    }
+  }
+  return nullptr;
+}
+
+TreeStoreElem *TreeHash::lookup_any(const short type, const short nr, ID *id) const
+{
+  const TseGroup *group = lookup_group(type, nr, id);
+  return group ? group->elems[0] : nullptr;
+}
+
+/** \} */
+
+}  // namespace blender::bke::outliner::treehash
diff --git a/source/blender/blenkernel/intern/packedFile.c b/source/blender/blenkernel/intern/packedFile.c
index 7c96c463339..901b42ac0b2 100644
--- a/source/blender/blenkernel/intern/packedFile.c
+++ b/source/blender/blenkernel/intern/packedFile.c
@@ -526,21 +526,27 @@ static void unpack_generate_paths(const char *name,
     BLI_strncpy(tempdir, "//", sizeof(tempdir));
   }
 
-  switch (id_type) {
-    case ID_VF:
-      BLI_snprintf(r_relpath, relpathlen, "//fonts/%s", tempname);
-      break;
-    case ID_SO:
-      BLI_snprintf(r_relpath, relpathlen, "//sounds/%s", tempname);
-      break;
-    case ID_IM:
-      BLI_snprintf(r_relpath, relpathlen, "//textures/%s", tempname);
-      break;
-    case ID_VO:
-      BLI_snprintf(r_relpath, relpathlen, "//volumes/%s", tempname);
-      break;
-    default:
-      break;
+  {
+    const char *dir_name = NULL;
+    switch (id_type) {
+      case ID_VF:
+        dir_name = "fonts";
+        break;
+      case ID_SO:
+        dir_name = "sounds";
+        break;
+      case ID_IM:
+        dir_name = "textures";
+        break;
+      case ID_VO:
+        dir_name = "volumes";
+        break;
+      default:
+        break;
+    }
+    if (dir_name) {
+      BLI_path_join(r_relpath, relpathlen, "//", dir_name, tempname, NULL);
+    }
   }
 
   {
diff --git a/source/blender/blenkernel/intern/paint.c b/source/blender/blenkernel/intern/paint.c
deleted file mode 100644
index 89cc25b31e6..00000000000
--- a/source/blender/blenkernel/intern/paint.c
+++ /dev/null
@@ -1,2348 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later
- * Copyright 2009 by Nicholas Bishop. All rights reserved. */
-
-/** \file
- * \ingroup bke
- */
-
-#include 
-#include 
-
-#include "MEM_guardedalloc.h"
-
-#include "DNA_brush_types.h"
-#include "DNA_gpencil_types.h"
-#include "DNA_mesh_types.h"
-#include "DNA_meshdata_types.h"
-#include "DNA_modifier_types.h"
-#include "DNA_object_types.h"
-#include "DNA_scene_types.h"
-#include "DNA_space_types.h"
-#include "DNA_view3d_types.h"
-#include "DNA_workspace_types.h"
-
-#include "BLI_bitmap.h"
-#include "BLI_hash.h"
-#include "BLI_listbase.h"
-#include "BLI_math_vector.h"
-#include "BLI_utildefines.h"
-
-#include "BLT_translation.h"
-
-#include "BKE_attribute.h"
-#include "BKE_brush.h"
-#include "BKE_ccg.h"
-#include "BKE_colortools.h"
-#include "BKE_context.h"
-#include "BKE_crazyspace.h"
-#include "BKE_deform.h"
-#include "BKE_gpencil.h"
-#include "BKE_idtype.h"
-#include "BKE_image.h"
-#include "BKE_key.h"
-#include "BKE_lib_id.h"
-#include "BKE_main.h"
-#include "BKE_material.h"
-#include "BKE_mesh.h"
-#include "BKE_mesh_mapping.h"
-#include "BKE_mesh_runtime.h"
-#include "BKE_modifier.h"
-#include "BKE_multires.h"
-#include "BKE_object.h"
-#include "BKE_paint.h"
-#include "BKE_pbvh.h"
-#include "BKE_subdiv_ccg.h"
-#include "BKE_subsurf.h"
-
-#include "DEG_depsgraph.h"
-#include "DEG_depsgraph_query.h"
-
-#include "RNA_enum_types.h"
-
-#include "BLO_read_write.h"
-
-#include "bmesh.h"
-
-static void palette_init_data(ID *id)
-{
-  Palette *palette = (Palette *)id;
-
-  BLI_assert(MEMCMP_STRUCT_AFTER_IS_ZERO(palette, id));
-
-  /* Enable fake user by default. */
-  id_fake_user_set(&palette->id);
-}
-
-static void palette_copy_data(Main *UNUSED(bmain),
-                              ID *id_dst,
-                              const ID *id_src,
-                              const int UNUSED(flag))
-{
-  Palette *palette_dst = (Palette *)id_dst;
-  const Palette *palette_src = (const Palette *)id_src;
-
-  BLI_duplicatelist(&palette_dst->colors, &palette_src->colors);
-}
-
-static void palette_free_data(ID *id)
-{
-  Palette *palette = (Palette *)id;
-
-  BLI_freelistN(&palette->colors);
-}
-
-static void palette_blend_write(BlendWriter *writer, ID *id, const void *id_address)
-{
-  Palette *palette = (Palette *)id;
-
-  PaletteColor *color;
-  BLO_write_id_struct(writer, Palette, id_address, &palette->id);
-  BKE_id_blend_write(writer, &palette->id);
-
-  for (color = palette->colors.first; color; color = color->next) {
-    BLO_write_struct(writer, PaletteColor, color);
-  }
-}
-
-static void palette_blend_read_data(BlendDataReader *reader, ID *id)
-{
-  Palette *palette = (Palette *)id;
-  BLO_read_list(reader, &palette->colors);
-}
-
-static void palette_undo_preserve(BlendLibReader *UNUSED(reader), ID *id_new, ID *id_old)
-{
-  /* Whole Palette is preserved across undo-steps, and it has no extra pointer, simple. */
-  /* NOTE: We do not care about potential internal references to self here, Palette has none. */
-  /* NOTE: We do not swap IDProperties, as dealing with potential ID pointers in those would be
-   *       fairly delicate. */
-  BKE_lib_id_swap(NULL, id_new, id_old);
-  SWAP(IDProperty *, id_new->properties, id_old->properties);
-}
-
-IDTypeInfo IDType_ID_PAL = {
-    .id_code = ID_PAL,
-    .id_filter = FILTER_ID_PAL,
-    .main_listbase_index = INDEX_ID_PAL,
-    .struct_size = sizeof(Palette),
-    .name = "Palette",
-    .name_plural = "palettes",
-    .translation_context = BLT_I18NCONTEXT_ID_PALETTE,
-    .flags = IDTYPE_FLAGS_NO_ANIMDATA,
-    .asset_type_info = NULL,
-
-    .init_data = palette_init_data,
-    .copy_data = palette_copy_data,
-    .free_data = palette_free_data,
-    .make_local = NULL,
-    .foreach_id = NULL,
-    .foreach_cache = NULL,
-    .foreach_path = NULL,
-    .owner_get = NULL,
-
-    .blend_write = palette_blend_write,
-    .blend_read_data = palette_blend_read_data,
-    .blend_read_lib = NULL,
-    .blend_read_expand = NULL,
-
-    .blend_read_undo_preserve = palette_undo_preserve,
-
-    .lib_override_apply_post = NULL,
-};
-
-static void paint_curve_copy_data(Main *UNUSED(bmain),
-                                  ID *id_dst,
-                                  const ID *id_src,
-                                  const int UNUSED(flag))
-{
-  PaintCurve *paint_curve_dst = (PaintCurve *)id_dst;
-  const PaintCurve *paint_curve_src = (const PaintCurve *)id_src;
-
-  if (paint_curve_src->tot_points != 0) {
-    paint_curve_dst->points = MEM_dupallocN(paint_curve_src->points);
-  }
-}
-
-static void paint_curve_free_data(ID *id)
-{
-  PaintCurve *paint_curve = (PaintCurve *)id;
-
-  MEM_SAFE_FREE(paint_curve->points);
-  paint_curve->tot_points = 0;
-}
-
-static void paint_curve_blend_write(BlendWriter *writer, ID *id, const void *id_address)
-{
-  PaintCurve *pc = (PaintCurve *)id;
-
-  BLO_write_id_struct(writer, PaintCurve, id_address, &pc->id);
-  BKE_id_blend_write(writer, &pc->id);
-
-  BLO_write_struct_array(writer, PaintCurvePoint, pc->tot_points, pc->points);
-}
-
-static void paint_curve_blend_read_data(BlendDataReader *reader, ID *id)
-{
-  PaintCurve *pc = (PaintCurve *)id;
-  BLO_read_data_address(reader, &pc->points);
-}
-
-IDTypeInfo IDType_ID_PC = {
-    .id_code = ID_PC,
-    .id_filter = FILTER_ID_PC,
-    .main_listbase_index = INDEX_ID_PC,
-    .struct_size = sizeof(PaintCurve),
-    .name = "PaintCurve",
-    .name_plural = "paint_curves",
-    .translation_context = BLT_I18NCONTEXT_ID_PAINTCURVE,
-    .flags = IDTYPE_FLAGS_NO_ANIMDATA,
-    .asset_type_info = NULL,
-
-    .init_data = NULL,
-    .copy_data = paint_curve_copy_data,
-    .free_data = paint_curve_free_data,
-    .make_local = NULL,
-    .foreach_id = NULL,
-    .foreach_cache = NULL,
-    .foreach_path = NULL,
-    .owner_get = NULL,
-
-    .blend_write = paint_curve_blend_write,
-    .blend_read_data = paint_curve_blend_read_data,
-    .blend_read_lib = NULL,
-    .blend_read_expand = NULL,
-
-    .blend_read_undo_preserve = NULL,
-
-    .lib_override_apply_post = NULL,
-};
-
-const char PAINT_CURSOR_SCULPT[3] = {255, 100, 100};
-const char PAINT_CURSOR_VERTEX_PAINT[3] = {255, 255, 255};
-const char PAINT_CURSOR_WEIGHT_PAINT[3] = {200, 200, 255};
-const char PAINT_CURSOR_TEXTURE_PAINT[3] = {255, 255, 255};
-
-static ePaintOverlayControlFlags overlay_flags = 0;
-
-void BKE_paint_invalidate_overlay_tex(Scene *scene, ViewLayer *view_layer, const Tex *tex)
-{
-  Paint *p = BKE_paint_get_active(scene, view_layer);
-  if (!p) {
-    return;
-  }
-
-  Brush *br = p->brush;
-  if (!br) {
-    return;
-  }
-
-  if (br->mtex.tex == tex) {
-    overlay_flags |= PAINT_OVERLAY_INVALID_TEXTURE_PRIMARY;
-  }
-  if (br->mask_mtex.tex == tex) {
-    overlay_flags |= PAINT_OVERLAY_INVALID_TEXTURE_SECONDARY;
-  }
-}
-
-void BKE_paint_invalidate_cursor_overlay(Scene *scene, ViewLayer *view_layer, CurveMapping *curve)
-{
-  Paint *p = BKE_paint_get_active(scene, view_layer);
-  if (p == NULL) {
-    return;
-  }
-
-  Brush *br = p->brush;
-  if (br && br->curve == curve) {
-    overlay_flags |= PAINT_OVERLAY_INVALID_CURVE;
-  }
-}
-
-void BKE_paint_invalidate_overlay_all(void)
-{
-  overlay_flags |= (PAINT_OVERLAY_INVALID_TEXTURE_SECONDARY |
-                    PAINT_OVERLAY_INVALID_TEXTURE_PRIMARY | PAINT_OVERLAY_INVALID_CURVE);
-}
-
-ePaintOverlayControlFlags BKE_paint_get_overlay_flags(void)
-{
-  return overlay_flags;
-}
-
-void BKE_paint_set_overlay_override(eOverlayFlags flags)
-{
-  if (flags & BRUSH_OVERLAY_OVERRIDE_MASK) {
-    if (flags & BRUSH_OVERLAY_CURSOR_OVERRIDE_ON_STROKE) {
-      overlay_flags |= PAINT_OVERLAY_OVERRIDE_CURSOR;
-    }
-    if (flags & BRUSH_OVERLAY_PRIMARY_OVERRIDE_ON_STROKE) {
-      overlay_flags |= PAINT_OVERLAY_OVERRIDE_PRIMARY;
-    }
-    if (flags & BRUSH_OVERLAY_SECONDARY_OVERRIDE_ON_STROKE) {
-      overlay_flags |= PAINT_OVERLAY_OVERRIDE_SECONDARY;
-    }
-  }
-  else {
-    overlay_flags &= ~(PAINT_OVERRIDE_MASK);
-  }
-}
-
-void BKE_paint_reset_overlay_invalid(ePaintOverlayControlFlags flag)
-{
-  overlay_flags &= ~(flag);
-}
-
-bool BKE_paint_ensure_from_paintmode(Scene *sce, ePaintMode mode)
-{
-  ToolSettings *ts = sce->toolsettings;
-  Paint **paint_ptr = NULL;
-  /* Some paint modes don't store paint settings as pointer, for these this can be set and
-   * referenced by paint_ptr. */
-  Paint *paint_tmp = NULL;
-
-  switch (mode) {
-    case PAINT_MODE_SCULPT:
-      paint_ptr = (Paint **)&ts->sculpt;
-      break;
-    case PAINT_MODE_VERTEX:
-      paint_ptr = (Paint **)&ts->vpaint;
-      break;
-    case PAINT_MODE_WEIGHT:
-      paint_ptr = (Paint **)&ts->wpaint;
-      break;
-    case PAINT_MODE_TEXTURE_2D:
-    case PAINT_MODE_TEXTURE_3D:
-      paint_tmp = (Paint *)&ts->imapaint;
-      paint_ptr = &paint_tmp;
-      break;
-    case PAINT_MODE_SCULPT_UV:
-      paint_ptr = (Paint **)&ts->uvsculpt;
-      break;
-    case PAINT_MODE_GPENCIL:
-      paint_ptr = (Paint **)&ts->gp_paint;
-      break;
-    case PAINT_MODE_VERTEX_GPENCIL:
-      paint_ptr = (Paint **)&ts->gp_vertexpaint;
-      break;
-    case PAINT_MODE_SCULPT_GPENCIL:
-      paint_ptr = (Paint **)&ts->gp_sculptpaint;
-      break;
-    case PAINT_MODE_WEIGHT_GPENCIL:
-      paint_ptr = (Paint **)&ts->gp_weightpaint;
-      break;
-    case PAINT_MODE_SCULPT_CURVES:
-      paint_ptr = (Paint **)&ts->curves_sculpt;
-      break;
-    case PAINT_MODE_INVALID:
-      break;
-  }
-  if (paint_ptr) {
-    BKE_paint_ensure(ts, paint_ptr);
-    return true;
-  }
-  return false;
-}
-
-Paint *BKE_paint_get_active_from_paintmode(Scene *sce, ePaintMode mode)
-{
-  if (sce) {
-    ToolSettings *ts = sce->toolsettings;
-
-    switch (mode) {
-      case PAINT_MODE_SCULPT:
-        return &ts->sculpt->paint;
-      case PAINT_MODE_VERTEX:
-        return &ts->vpaint->paint;
-      case PAINT_MODE_WEIGHT:
-        return &ts->wpaint->paint;
-      case PAINT_MODE_TEXTURE_2D:
-      case PAINT_MODE_TEXTURE_3D:
-        return &ts->imapaint.paint;
-      case PAINT_MODE_SCULPT_UV:
-        return &ts->uvsculpt->paint;
-      case PAINT_MODE_GPENCIL:
-        return &ts->gp_paint->paint;
-      case PAINT_MODE_VERTEX_GPENCIL:
-        return &ts->gp_vertexpaint->paint;
-      case PAINT_MODE_SCULPT_GPENCIL:
-        return &ts->gp_sculptpaint->paint;
-      case PAINT_MODE_WEIGHT_GPENCIL:
-        return &ts->gp_weightpaint->paint;
-      case PAINT_MODE_SCULPT_CURVES:
-        return &ts->curves_sculpt->paint;
-      case PAINT_MODE_INVALID:
-        return NULL;
-      default:
-        return &ts->imapaint.paint;
-    }
-  }
-
-  return NULL;
-}
-
-const EnumPropertyItem *BKE_paint_get_tool_enum_from_paintmode(ePaintMode mode)
-{
-  switch (mode) {
-    case PAINT_MODE_SCULPT:
-      return rna_enum_brush_sculpt_tool_items;
-    case PAINT_MODE_VERTEX:
-      return rna_enum_brush_vertex_tool_items;
-    case PAINT_MODE_WEIGHT:
-      return rna_enum_brush_weight_tool_items;
-    case PAINT_MODE_TEXTURE_2D:
-    case PAINT_MODE_TEXTURE_3D:
-      return rna_enum_brush_image_tool_items;
-    case PAINT_MODE_SCULPT_UV:
-      return rna_enum_brush_uv_sculpt_tool_items;
-    case PAINT_MODE_GPENCIL:
-      return rna_enum_brush_gpencil_types_items;
-    case PAINT_MODE_VERTEX_GPENCIL:
-      return rna_enum_brush_gpencil_vertex_types_items;
-    case PAINT_MODE_SCULPT_GPENCIL:
-      return rna_enum_brush_gpencil_sculpt_types_items;
-    case PAINT_MODE_WEIGHT_GPENCIL:
-      return rna_enum_brush_gpencil_weight_types_items;
-    case PAINT_MODE_SCULPT_CURVES:
-      return rna_enum_brush_curves_sculpt_tool_items;
-    case PAINT_MODE_INVALID:
-      break;
-  }
-  return NULL;
-}
-
-const char *BKE_paint_get_tool_prop_id_from_paintmode(ePaintMode mode)
-{
-  switch (mode) {
-    case PAINT_MODE_SCULPT:
-      return "sculpt_tool";
-    case PAINT_MODE_VERTEX:
-      return "vertex_tool";
-    case PAINT_MODE_WEIGHT:
-      return "weight_tool";
-    case PAINT_MODE_TEXTURE_2D:
-    case PAINT_MODE_TEXTURE_3D:
-      return "image_tool";
-    case PAINT_MODE_SCULPT_UV:
-      return "uv_sculpt_tool";
-    case PAINT_MODE_GPENCIL:
-      return "gpencil_tool";
-    case PAINT_MODE_VERTEX_GPENCIL:
-      return "gpencil_vertex_tool";
-    case PAINT_MODE_SCULPT_GPENCIL:
-      return "gpencil_sculpt_tool";
-    case PAINT_MODE_WEIGHT_GPENCIL:
-      return "gpencil_weight_tool";
-    case PAINT_MODE_SCULPT_CURVES:
-      return "curves_sculpt_tool";
-    case PAINT_MODE_INVALID:
-      break;
-  }
-
-  /* Invalid paint mode. */
-  return NULL;
-}
-
-Paint *BKE_paint_get_active(Scene *sce, ViewLayer *view_layer)
-{
-  if (sce && view_layer) {
-    ToolSettings *ts = sce->toolsettings;
-
-    if (view_layer->basact && view_layer->basact->object) {
-      switch (view_layer->basact->object->mode) {
-        case OB_MODE_SCULPT:
-          return &ts->sculpt->paint;
-        case OB_MODE_VERTEX_PAINT:
-          return &ts->vpaint->paint;
-        case OB_MODE_WEIGHT_PAINT:
-          return &ts->wpaint->paint;
-        case OB_MODE_TEXTURE_PAINT:
-          return &ts->imapaint.paint;
-        case OB_MODE_PAINT_GPENCIL:
-          return &ts->gp_paint->paint;
-        case OB_MODE_VERTEX_GPENCIL:
-          return &ts->gp_vertexpaint->paint;
-        case OB_MODE_SCULPT_GPENCIL:
-          return &ts->gp_sculptpaint->paint;
-        case OB_MODE_WEIGHT_GPENCIL:
-          return &ts->gp_weightpaint->paint;
-        case OB_MODE_SCULPT_CURVES:
-          return &ts->curves_sculpt->paint;
-        case OB_MODE_EDIT:
-          return ts->uvsculpt ? &ts->uvsculpt->paint : NULL;
-        default:
-          break;
-      }
-    }
-
-    /* default to image paint */
-    return &ts->imapaint.paint;
-  }
-
-  return NULL;
-}
-
-Paint *BKE_paint_get_active_from_context(const bContext *C)
-{
-  Scene *sce = CTX_data_scene(C);
-  ViewLayer *view_layer = CTX_data_view_layer(C);
-  SpaceImage *sima;
-
-  if (sce && view_layer) {
-    ToolSettings *ts = sce->toolsettings;
-    Object *obact = NULL;
-
-    if (view_layer->basact && view_layer->basact->object) {
-      obact = view_layer->basact->object;
-    }
-
-    if ((sima = CTX_wm_space_image(C)) != NULL) {
-      if (obact && obact->mode == OB_MODE_EDIT) {
-        if (sima->mode == SI_MODE_PAINT) {
-          return &ts->imapaint.paint;
-        }
-        if (sima->mode == SI_MODE_UV) {
-          return &ts->uvsculpt->paint;
-        }
-      }
-      else {
-        return &ts->imapaint.paint;
-      }
-    }
-    else {
-      return BKE_paint_get_active(sce, view_layer);
-    }
-  }
-
-  return NULL;
-}
-
-ePaintMode BKE_paintmode_get_active_from_context(const bContext *C)
-{
-  Scene *sce = CTX_data_scene(C);
-  ViewLayer *view_layer = CTX_data_view_layer(C);
-  SpaceImage *sima;
-
-  if (sce && view_layer) {
-    Object *obact = NULL;
-
-    if (view_layer->basact && view_layer->basact->object) {
-      obact = view_layer->basact->object;
-    }
-
-    if ((sima = CTX_wm_space_image(C)) != NULL) {
-      if (obact && obact->mode == OB_MODE_EDIT) {
-        if (sima->mode == SI_MODE_PAINT) {
-          return PAINT_MODE_TEXTURE_2D;
-        }
-        if (sima->mode == SI_MODE_UV) {
-          return PAINT_MODE_SCULPT_UV;
-        }
-      }
-      else {
-        return PAINT_MODE_TEXTURE_2D;
-      }
-    }
-    else if (obact) {
-      switch (obact->mode) {
-        case OB_MODE_SCULPT:
-          return PAINT_MODE_SCULPT;
-        case OB_MODE_VERTEX_PAINT:
-          return PAINT_MODE_VERTEX;
-        case OB_MODE_WEIGHT_PAINT:
-          return PAINT_MODE_WEIGHT;
-        case OB_MODE_TEXTURE_PAINT:
-          return PAINT_MODE_TEXTURE_3D;
-        case OB_MODE_EDIT:
-          return PAINT_MODE_SCULPT_UV;
-        case OB_MODE_SCULPT_CURVES:
-          return PAINT_MODE_SCULPT_CURVES;
-        default:
-          return PAINT_MODE_TEXTURE_2D;
-      }
-    }
-    else {
-      /* default to image paint */
-      return PAINT_MODE_TEXTURE_2D;
-    }
-  }
-
-  return PAINT_MODE_INVALID;
-}
-
-ePaintMode BKE_paintmode_get_from_tool(const struct bToolRef *tref)
-{
-  if (tref->space_type == SPACE_VIEW3D) {
-    switch (tref->mode) {
-      case CTX_MODE_SCULPT:
-        return PAINT_MODE_SCULPT;
-      case CTX_MODE_PAINT_VERTEX:
-        return PAINT_MODE_VERTEX;
-      case CTX_MODE_PAINT_WEIGHT:
-        return PAINT_MODE_WEIGHT;
-      case CTX_MODE_PAINT_GPENCIL:
-        return PAINT_MODE_GPENCIL;
-      case CTX_MODE_PAINT_TEXTURE:
-        return PAINT_MODE_TEXTURE_3D;
-      case CTX_MODE_VERTEX_GPENCIL:
-        return PAINT_MODE_VERTEX_GPENCIL;
-      case CTX_MODE_SCULPT_GPENCIL:
-        return PAINT_MODE_SCULPT_GPENCIL;
-      case CTX_MODE_WEIGHT_GPENCIL:
-        return PAINT_MODE_WEIGHT_GPENCIL;
-      case CTX_MODE_SCULPT_CURVES:
-        return PAINT_MODE_SCULPT_CURVES;
-    }
-  }
-  else if (tref->space_type == SPACE_IMAGE) {
-    switch (tref->mode) {
-      case SI_MODE_PAINT:
-        return PAINT_MODE_TEXTURE_2D;
-      case SI_MODE_UV:
-        return PAINT_MODE_SCULPT_UV;
-    }
-  }
-
-  return PAINT_MODE_INVALID;
-}
-
-Brush *BKE_paint_brush(Paint *p)
-{
-  return (Brush *)BKE_paint_brush_for_read((const Paint *)p);
-}
-
-const Brush *BKE_paint_brush_for_read(const Paint *p)
-{
-  return p ? p->brush : NULL;
-}
-
-void BKE_paint_brush_set(Paint *p, Brush *br)
-{
-  if (p) {
-    id_us_min((ID *)p->brush);
-    id_us_plus((ID *)br);
-    p->brush = br;
-
-    BKE_paint_toolslots_brush_update(p);
-  }
-}
-
-void BKE_paint_runtime_init(const ToolSettings *ts, Paint *paint)
-{
-  if (paint == &ts->imapaint.paint) {
-    paint->runtime.tool_offset = offsetof(Brush, imagepaint_tool);
-    paint->runtime.ob_mode = OB_MODE_TEXTURE_PAINT;
-  }
-  else if (ts->sculpt && paint == &ts->sculpt->paint) {
-    paint->runtime.tool_offset = offsetof(Brush, sculpt_tool);
-    paint->runtime.ob_mode = OB_MODE_SCULPT;
-  }
-  else if (ts->vpaint && paint == &ts->vpaint->paint) {
-    paint->runtime.tool_offset = offsetof(Brush, vertexpaint_tool);
-    paint->runtime.ob_mode = OB_MODE_VERTEX_PAINT;
-  }
-  else if (ts->wpaint && paint == &ts->wpaint->paint) {
-    paint->runtime.tool_offset = offsetof(Brush, weightpaint_tool);
-    paint->runtime.ob_mode = OB_MODE_WEIGHT_PAINT;
-  }
-  else if (ts->uvsculpt && paint == &ts->uvsculpt->paint) {
-    paint->runtime.tool_offset = offsetof(Brush, uv_sculpt_tool);
-    paint->runtime.ob_mode = OB_MODE_EDIT;
-  }
-  else if (ts->gp_paint && paint == &ts->gp_paint->paint) {
-    paint->runtime.tool_offset = offsetof(Brush, gpencil_tool);
-    paint->runtime.ob_mode = OB_MODE_PAINT_GPENCIL;
-  }
-  else if (ts->gp_vertexpaint && paint == &ts->gp_vertexpaint->paint) {
-    paint->runtime.tool_offset = offsetof(Brush, gpencil_vertex_tool);
-    paint->runtime.ob_mode = OB_MODE_VERTEX_GPENCIL;
-  }
-  else if (ts->gp_sculptpaint && paint == &ts->gp_sculptpaint->paint) {
-    paint->runtime.tool_offset = offsetof(Brush, gpencil_sculpt_tool);
-    paint->runtime.ob_mode = OB_MODE_SCULPT_GPENCIL;
-  }
-  else if (ts->gp_weightpaint && paint == &ts->gp_weightpaint->paint) {
-    paint->runtime.tool_offset = offsetof(Brush, gpencil_weight_tool);
-    paint->runtime.ob_mode = OB_MODE_WEIGHT_GPENCIL;
-  }
-  else if (ts->curves_sculpt && paint == &ts->curves_sculpt->paint) {
-    paint->runtime.tool_offset = offsetof(Brush, curves_sculpt_tool);
-    paint->runtime.ob_mode = OB_MODE_SCULPT_CURVES;
-  }
-  else {
-    BLI_assert_unreachable();
-  }
-}
-
-uint BKE_paint_get_brush_tool_offset_from_paintmode(const ePaintMode mode)
-{
-  switch (mode) {
-    case PAINT_MODE_TEXTURE_2D:
-    case PAINT_MODE_TEXTURE_3D:
-      return offsetof(Brush, imagepaint_tool);
-    case PAINT_MODE_SCULPT:
-      return offsetof(Brush, sculpt_tool);
-    case PAINT_MODE_VERTEX:
-      return offsetof(Brush, vertexpaint_tool);
-    case PAINT_MODE_WEIGHT:
-      return offsetof(Brush, weightpaint_tool);
-    case PAINT_MODE_SCULPT_UV:
-      return offsetof(Brush, uv_sculpt_tool);
-    case PAINT_MODE_GPENCIL:
-      return offsetof(Brush, gpencil_tool);
-    case PAINT_MODE_VERTEX_GPENCIL:
-      return offsetof(Brush, gpencil_vertex_tool);
-    case PAINT_MODE_SCULPT_GPENCIL:
-      return offsetof(Brush, gpencil_sculpt_tool);
-    case PAINT_MODE_WEIGHT_GPENCIL:
-      return offsetof(Brush, gpencil_weight_tool);
-    case PAINT_MODE_SCULPT_CURVES:
-      return offsetof(Brush, curves_sculpt_tool);
-    case PAINT_MODE_INVALID:
-      break; /* We don't use these yet. */
-  }
-  return 0;
-}
-
-PaintCurve *BKE_paint_curve_add(Main *bmain, const char *name)
-{
-  PaintCurve *pc;
-
-  pc = BKE_id_new(bmain, ID_PC, name);
-
-  return pc;
-}
-
-Palette *BKE_paint_palette(Paint *p)
-{
-  return p ? p->palette : NULL;
-}
-
-void BKE_paint_palette_set(Paint *p, Palette *palette)
-{
-  if (p) {
-    id_us_min((ID *)p->palette);
-    p->palette = palette;
-    id_us_plus((ID *)p->palette);
-  }
-}
-
-void BKE_paint_curve_set(Brush *br, PaintCurve *pc)
-{
-  if (br) {
-    id_us_min((ID *)br->paint_curve);
-    br->paint_curve = pc;
-    id_us_plus((ID *)br->paint_curve);
-  }
-}
-
-void BKE_paint_curve_clamp_endpoint_add_index(PaintCurve *pc, const int add_index)
-{
-  pc->add_index = (add_index || pc->tot_points == 1) ? (add_index + 1) : 0;
-}
-
-void BKE_palette_color_remove(Palette *palette, PaletteColor *color)
-{
-  if (BLI_listbase_count_at_most(&palette->colors, palette->active_color) ==
-      palette->active_color) {
-    palette->active_color--;
-  }
-
-  BLI_remlink(&palette->colors, color);
-
-  if (palette->active_color < 0 && !BLI_listbase_is_empty(&palette->colors)) {
-    palette->active_color = 0;
-  }
-
-  MEM_freeN(color);
-}
-
-void BKE_palette_clear(Palette *palette)
-{
-  BLI_freelistN(&palette->colors);
-  palette->active_color = 0;
-}
-
-Palette *BKE_palette_add(Main *bmain, const char *name)
-{
-  Palette *palette = BKE_id_new(bmain, ID_PAL, name);
-  return palette;
-}
-
-PaletteColor *BKE_palette_color_add(Palette *palette)
-{
-  PaletteColor *color = MEM_callocN(sizeof(*color), "Palette Color");
-  BLI_addtail(&palette->colors, color);
-  return color;
-}
-
-bool BKE_palette_is_empty(const struct Palette *palette)
-{
-  return BLI_listbase_is_empty(&palette->colors);
-}
-
-/* helper function to sort using qsort */
-static int palettecolor_compare_hsv(const void *a1, const void *a2)
-{
-  const tPaletteColorHSV *ps1 = a1, *ps2 = a2;
-
-  /* Hue */
-  if (ps1->h > ps2->h) {
-    return 1;
-  }
-  if (ps1->h < ps2->h) {
-    return -1;
-  }
-
-  /* Saturation. */
-  if (ps1->s > ps2->s) {
-    return 1;
-  }
-  if (ps1->s < ps2->s) {
-    return -1;
-  }
-
-  /* Value. */
-  if (1.0f - ps1->v > 1.0f - ps2->v) {
-    return 1;
-  }
-  if (1.0f - ps1->v < 1.0f - ps2->v) {
-    return -1;
-  }
-
-  return 0;
-}
-
-/* helper function to sort using qsort */
-static int palettecolor_compare_svh(const void *a1, const void *a2)
-{
-  const tPaletteColorHSV *ps1 = a1, *ps2 = a2;
-
-  /* Saturation. */
-  if (ps1->s > ps2->s) {
-    return 1;
-  }
-  if (ps1->s < ps2->s) {
-    return -1;
-  }
-
-  /* Value. */
-  if (1.0f - ps1->v > 1.0f - ps2->v) {
-    return 1;
-  }
-  if (1.0f - ps1->v < 1.0f - ps2->v) {
-    return -1;
-  }
-
-  /* Hue */
-  if (ps1->h > ps2->h) {
-    return 1;
-  }
-  if (ps1->h < ps2->h) {
-    return -1;
-  }
-
-  return 0;
-}
-
-static int palettecolor_compare_vhs(const void *a1, const void *a2)
-{
-  const tPaletteColorHSV *ps1 = a1, *ps2 = a2;
-
-  /* Value. */
-  if (1.0f - ps1->v > 1.0f - ps2->v) {
-    return 1;
-  }
-  if (1.0f - ps1->v < 1.0f - ps2->v) {
-    return -1;
-  }
-
-  /* Hue */
-  if (ps1->h > ps2->h) {
-    return 1;
-  }
-  if (ps1->h < ps2->h) {
-    return -1;
-  }
-
-  /* Saturation. */
-  if (ps1->s > ps2->s) {
-    return 1;
-  }
-  if (ps1->s < ps2->s) {
-    return -1;
-  }
-
-  return 0;
-}
-
-static int palettecolor_compare_luminance(const void *a1, const void *a2)
-{
-  const tPaletteColorHSV *ps1 = a1, *ps2 = a2;
-
-  float lumi1 = (ps1->rgb[0] + ps1->rgb[1] + ps1->rgb[2]) / 3.0f;
-  float lumi2 = (ps2->rgb[0] + ps2->rgb[1] + ps2->rgb[2]) / 3.0f;
-
-  if (lumi1 > lumi2) {
-    return -1;
-  }
-  if (lumi1 < lumi2) {
-    return 1;
-  }
-
-  return 0;
-}
-
-void BKE_palette_sort_hsv(tPaletteColorHSV *color_array, const int totcol)
-{
-  /* Sort by Hue, Saturation and Value. */
-  qsort(color_array, totcol, sizeof(tPaletteColorHSV), palettecolor_compare_hsv);
-}
-
-void BKE_palette_sort_svh(tPaletteColorHSV *color_array, const int totcol)
-{
-  /* Sort by Saturation, Value and Hue. */
-  qsort(color_array, totcol, sizeof(tPaletteColorHSV), palettecolor_compare_svh);
-}
-
-void BKE_palette_sort_vhs(tPaletteColorHSV *color_array, const int totcol)
-{
-  /* Sort by Saturation, Value and Hue. */
-  qsort(color_array, totcol, sizeof(tPaletteColorHSV), palettecolor_compare_vhs);
-}
-
-void BKE_palette_sort_luminance(tPaletteColorHSV *color_array, const int totcol)
-{
-  /* Sort by Luminance (calculated with the average, enough for sorting). */
-  qsort(color_array, totcol, sizeof(tPaletteColorHSV), palettecolor_compare_luminance);
-}
-
-bool BKE_palette_from_hash(Main *bmain, GHash *color_table, const char *name, const bool linear)
-{
-  tPaletteColorHSV *color_array = NULL;
-  tPaletteColorHSV *col_elm = NULL;
-  bool done = false;
-
-  const int totpal = BLI_ghash_len(color_table);
-
-  if (totpal > 0) {
-    color_array = MEM_calloc_arrayN(totpal, sizeof(tPaletteColorHSV), __func__);
-    /* Put all colors in an array. */
-    GHashIterator gh_iter;
-    int t = 0;
-    GHASH_ITER (gh_iter, color_table) {
-      const uint col = POINTER_AS_INT(BLI_ghashIterator_getValue(&gh_iter));
-      float r, g, b;
-      float h, s, v;
-      cpack_to_rgb(col, &r, &g, &b);
-      rgb_to_hsv(r, g, b, &h, &s, &v);
-
-      col_elm = &color_array[t];
-      col_elm->rgb[0] = r;
-      col_elm->rgb[1] = g;
-      col_elm->rgb[2] = b;
-      col_elm->h = h;
-      col_elm->s = s;
-      col_elm->v = v;
-      t++;
-    }
-  }
-
-  /* Create the Palette. */
-  if (totpal > 0) {
-    /* Sort by Hue and saturation. */
-    BKE_palette_sort_hsv(color_array, totpal);
-
-    Palette *palette = BKE_palette_add(bmain, name);
-    if (palette) {
-      for (int i = 0; i < totpal; i++) {
-        col_elm = &color_array[i];
-        PaletteColor *palcol = BKE_palette_color_add(palette);
-        if (palcol) {
-          copy_v3_v3(palcol->rgb, col_elm->rgb);
-          if (linear) {
-            linearrgb_to_srgb_v3_v3(palcol->rgb, palcol->rgb);
-          }
-        }
-      }
-      done = true;
-    }
-  }
-  else {
-    done = false;
-  }
-
-  if (totpal > 0) {
-    MEM_SAFE_FREE(color_array);
-  }
-
-  return done;
-}
-
-bool BKE_paint_select_face_test(Object *ob)
-{
-  return ((ob != NULL) && (ob->type == OB_MESH) && (ob->data != NULL) &&
-          (((Mesh *)ob->data)->editflag & ME_EDIT_PAINT_FACE_SEL) &&
-          (ob->mode & (OB_MODE_VERTEX_PAINT | OB_MODE_WEIGHT_PAINT | OB_MODE_TEXTURE_PAINT)));
-}
-
-bool BKE_paint_select_vert_test(Object *ob)
-{
-  return ((ob != NULL) && (ob->type == OB_MESH) && (ob->data != NULL) &&
-          (((Mesh *)ob->data)->editflag & ME_EDIT_PAINT_VERT_SEL) &&
-          (ob->mode & OB_MODE_WEIGHT_PAINT || ob->mode & OB_MODE_VERTEX_PAINT));
-}
-
-bool BKE_paint_select_elem_test(Object *ob)
-{
-  return (BKE_paint_select_vert_test(ob) || BKE_paint_select_face_test(ob));
-}
-
-void BKE_paint_cavity_curve_preset(Paint *p, int preset)
-{
-  CurveMapping *cumap = NULL;
-  CurveMap *cuma = NULL;
-
-  if (!p->cavity_curve) {
-    p->cavity_curve = BKE_curvemapping_add(1, 0, 0, 1, 1);
-  }
-  cumap = p->cavity_curve;
-  cumap->flag &= ~CUMA_EXTEND_EXTRAPOLATE;
-  cumap->preset = preset;
-
-  cuma = cumap->cm;
-  BKE_curvemap_reset(cuma, &cumap->clipr, cumap->preset, CURVEMAP_SLOPE_POSITIVE);
-  BKE_curvemapping_changed(cumap, false);
-}
-
-eObjectMode BKE_paint_object_mode_from_paintmode(ePaintMode mode)
-{
-  switch (mode) {
-    case PAINT_MODE_SCULPT:
-      return OB_MODE_SCULPT;
-    case PAINT_MODE_VERTEX:
-      return OB_MODE_VERTEX_PAINT;
-    case PAINT_MODE_WEIGHT:
-      return OB_MODE_WEIGHT_PAINT;
-    case PAINT_MODE_TEXTURE_2D:
-    case PAINT_MODE_TEXTURE_3D:
-      return OB_MODE_TEXTURE_PAINT;
-    case PAINT_MODE_SCULPT_UV:
-      return OB_MODE_EDIT;
-    case PAINT_MODE_INVALID:
-    default:
-      return 0;
-  }
-}
-
-bool BKE_paint_ensure(ToolSettings *ts, struct Paint **r_paint)
-{
-  Paint *paint = NULL;
-  if (*r_paint) {
-    /* Tool offset should never be 0 for initialized paint settings, so it's a reliable way to
-     * check if already initialized. */
-    if ((*r_paint)->runtime.tool_offset == 0) {
-      /* Currently only image painting is initialized this way, others have to be allocated. */
-      BLI_assert(ELEM(*r_paint, (Paint *)&ts->imapaint));
-
-      BKE_paint_runtime_init(ts, *r_paint);
-    }
-    else {
-      BLI_assert(ELEM(*r_paint,
-                      /* Cast is annoying, but prevent NULL-pointer access. */
-                      (Paint *)ts->gp_paint,
-                      (Paint *)ts->gp_vertexpaint,
-                      (Paint *)ts->gp_sculptpaint,
-                      (Paint *)ts->gp_weightpaint,
-                      (Paint *)ts->sculpt,
-                      (Paint *)ts->vpaint,
-                      (Paint *)ts->wpaint,
-                      (Paint *)ts->uvsculpt,
-                      (Paint *)ts->curves_sculpt,
-                      (Paint *)&ts->imapaint));
-#ifdef DEBUG
-      struct Paint paint_test = **r_paint;
-      BKE_paint_runtime_init(ts, *r_paint);
-      /* Swap so debug doesn't hide errors when release fails. */
-      SWAP(Paint, **r_paint, paint_test);
-      BLI_assert(paint_test.runtime.ob_mode == (*r_paint)->runtime.ob_mode);
-      BLI_assert(paint_test.runtime.tool_offset == (*r_paint)->runtime.tool_offset);
-#endif
-    }
-    return true;
-  }
-
-  if (((VPaint **)r_paint == &ts->vpaint) || ((VPaint **)r_paint == &ts->wpaint)) {
-    VPaint *data = MEM_callocN(sizeof(*data), __func__);
-    paint = &data->paint;
-  }
-  else if ((Sculpt **)r_paint == &ts->sculpt) {
-    Sculpt *data = MEM_callocN(sizeof(*data), __func__);
-    paint = &data->paint;
-
-    /* Turn on X plane mirror symmetry by default */
-    paint->symmetry_flags |= PAINT_SYMM_X;
-
-    /* Make sure at least dyntopo subdivision is enabled */
-    data->flags |= SCULPT_DYNTOPO_SUBDIVIDE | SCULPT_DYNTOPO_COLLAPSE;
-  }
-  else if ((GpPaint **)r_paint == &ts->gp_paint) {
-    GpPaint *data = MEM_callocN(sizeof(*data), __func__);
-    paint = &data->paint;
-  }
-  else if ((GpVertexPaint **)r_paint == &ts->gp_vertexpaint) {
-    GpVertexPaint *data = MEM_callocN(sizeof(*data), __func__);
-    paint = &data->paint;
-  }
-  else if ((GpSculptPaint **)r_paint == &ts->gp_sculptpaint) {
-    GpSculptPaint *data = MEM_callocN(sizeof(*data), __func__);
-    paint = &data->paint;
-  }
-  else if ((GpWeightPaint **)r_paint == &ts->gp_weightpaint) {
-    GpWeightPaint *data = MEM_callocN(sizeof(*data), __func__);
-    paint = &data->paint;
-  }
-  else if ((UvSculpt **)r_paint == &ts->uvsculpt) {
-    UvSculpt *data = MEM_callocN(sizeof(*data), __func__);
-    paint = &data->paint;
-  }
-  else if ((CurvesSculpt **)r_paint == &ts->curves_sculpt) {
-    CurvesSculpt *data = MEM_callocN(sizeof(*data), __func__);
-    paint = &data->paint;
-  }
-  else if (*r_paint == &ts->imapaint.paint) {
-    paint = &ts->imapaint.paint;
-  }
-
-  paint->flags |= PAINT_SHOW_BRUSH;
-
-  *r_paint = paint;
-
-  BKE_paint_runtime_init(ts, paint);
-
-  return false;
-}
-
-void BKE_paint_init(Main *bmain, Scene *sce, ePaintMode mode, const char col[3])
-{
-  UnifiedPaintSettings *ups = &sce->toolsettings->unified_paint_settings;
-  Paint *paint = BKE_paint_get_active_from_paintmode(sce, mode);
-
-  BKE_paint_ensure_from_paintmode(sce, mode);
-
-  /* If there's no brush, create one */
-  if (PAINT_MODE_HAS_BRUSH(mode)) {
-    Brush *brush = BKE_paint_brush(paint);
-    if (brush == NULL) {
-      eObjectMode ob_mode = BKE_paint_object_mode_from_paintmode(mode);
-      brush = BKE_brush_first_search(bmain, ob_mode);
-      if (!brush) {
-        brush = BKE_brush_add(bmain, "Brush", ob_mode);
-        id_us_min(&brush->id); /* fake user only */
-      }
-      BKE_paint_brush_set(paint, brush);
-    }
-  }
-
-  memcpy(paint->paint_cursor_col, col, 3);
-  paint->paint_cursor_col[3] = 128;
-  ups->last_stroke_valid = false;
-  zero_v3(ups->average_stroke_accum);
-  ups->average_stroke_counter = 0;
-  if (!paint->cavity_curve) {
-    BKE_paint_cavity_curve_preset(paint, CURVE_PRESET_LINE);
-  }
-}
-
-void BKE_paint_free(Paint *paint)
-{
-  BKE_curvemapping_free(paint->cavity_curve);
-  MEM_SAFE_FREE(paint->tool_slots);
-}
-
-void BKE_paint_copy(Paint *src, Paint *tar, const int flag)
-{
-  tar->brush = src->brush;
-  tar->cavity_curve = BKE_curvemapping_copy(src->cavity_curve);
-  tar->tool_slots = MEM_dupallocN(src->tool_slots);
-
-  if ((flag & LIB_ID_CREATE_NO_USER_REFCOUNT) == 0) {
-    id_us_plus((ID *)tar->brush);
-    id_us_plus((ID *)tar->palette);
-    if (src->tool_slots != NULL) {
-      for (int i = 0; i < tar->tool_slots_len; i++) {
-        id_us_plus((ID *)tar->tool_slots[i].brush);
-      }
-    }
-  }
-}
-
-void BKE_paint_stroke_get_average(Scene *scene, Object *ob, float stroke[3])
-{
-  UnifiedPaintSettings *ups = &scene->toolsettings->unified_paint_settings;
-  if (ups->last_stroke_valid && ups->average_stroke_counter > 0) {
-    float fac = 1.0f / ups->average_stroke_counter;
-    mul_v3_v3fl(stroke, ups->average_stroke_accum, fac);
-  }
-  else {
-    copy_v3_v3(stroke, ob->obmat[3]);
-  }
-}
-
-void BKE_paint_blend_write(BlendWriter *writer, Paint *p)
-{
-  if (p->cavity_curve) {
-    BKE_curvemapping_blend_write(writer, p->cavity_curve);
-  }
-  BLO_write_struct_array(writer, PaintToolSlot, p->tool_slots_len, p->tool_slots);
-}
-
-void BKE_paint_blend_read_data(BlendDataReader *reader, const Scene *scene, Paint *p)
-{
-  if (p->num_input_samples < 1) {
-    p->num_input_samples = 1;
-  }
-
-  BLO_read_data_address(reader, &p->cavity_curve);
-  if (p->cavity_curve) {
-    BKE_curvemapping_blend_read(reader, p->cavity_curve);
-  }
-  else {
-    BKE_paint_cavity_curve_preset(p, CURVE_PRESET_LINE);
-  }
-
-  BLO_read_data_address(reader, &p->tool_slots);
-
-  /* Workaround for invalid data written in older versions. */
-  const size_t expected_size = sizeof(PaintToolSlot) * p->tool_slots_len;
-  if (p->tool_slots && MEM_allocN_len(p->tool_slots) < expected_size) {
-    MEM_freeN(p->tool_slots);
-    p->tool_slots = MEM_callocN(expected_size, "PaintToolSlot");
-  }
-
-  BKE_paint_runtime_init(scene->toolsettings, p);
-}
-
-void BKE_paint_blend_read_lib(BlendLibReader *reader, Scene *sce, Paint *p)
-{
-  if (p) {
-    BLO_read_id_address(reader, sce->id.lib, &p->brush);
-    for (int i = 0; i < p->tool_slots_len; i++) {
-      if (p->tool_slots[i].brush != NULL) {
-        BLO_read_id_address(reader, sce->id.lib, &p->tool_slots[i].brush);
-      }
-    }
-    BLO_read_id_address(reader, sce->id.lib, &p->palette);
-    p->paint_cursor = NULL;
-
-    BKE_paint_runtime_init(sce->toolsettings, p);
-  }
-}
-
-bool paint_is_face_hidden(const MLoopTri *lt, const MVert *mvert, const MLoop *mloop)
-{
-  return ((mvert[mloop[lt->tri[0]].v].flag & ME_HIDE) ||
-          (mvert[mloop[lt->tri[1]].v].flag & ME_HIDE) ||
-          (mvert[mloop[lt->tri[2]].v].flag & ME_HIDE));
-}
-
-bool paint_is_grid_face_hidden(const uint *grid_hidden, int gridsize, int x, int y)
-{
-  /* skip face if any of its corners are hidden */
-  return (BLI_BITMAP_TEST(grid_hidden, y * gridsize + x) ||
-          BLI_BITMAP_TEST(grid_hidden, y * gridsize + x + 1) ||
-          BLI_BITMAP_TEST(grid_hidden, (y + 1) * gridsize + x + 1) ||
-          BLI_BITMAP_TEST(grid_hidden, (y + 1) * gridsize + x));
-}
-
-bool paint_is_bmesh_face_hidden(BMFace *f)
-{
-  BMLoop *l_iter;
-  BMLoop *l_first;
-
-  l_iter = l_first = BM_FACE_FIRST_LOOP(f);
-  do {
-    if (BM_elem_flag_test(l_iter->v, BM_ELEM_HIDDEN)) {
-      return true;
-    }
-  } while ((l_iter = l_iter->next) != l_first);
-
-  return false;
-}
-
-float paint_grid_paint_mask(const GridPaintMask *gpm, uint level, uint x, uint y)
-{
-  int factor = BKE_ccg_factor(level, gpm->level);
-  int gridsize = BKE_ccg_gridsize(gpm->level);
-
-  return gpm->data[(y * factor) * gridsize + (x * factor)];
-}
-
-/* threshold to move before updating the brush rotation */
-#define RAKE_THRESHHOLD 20
-
-void paint_update_brush_rake_rotation(UnifiedPaintSettings *ups, Brush *brush, float rotation)
-{
-  if (brush->mtex.brush_angle_mode & MTEX_ANGLE_RAKE) {
-    ups->brush_rotation = rotation;
-  }
-  else {
-    ups->brush_rotation = 0.0f;
-  }
-
-  if (brush->mask_mtex.brush_angle_mode & MTEX_ANGLE_RAKE) {
-    ups->brush_rotation_sec = rotation;
-  }
-  else {
-    ups->brush_rotation_sec = 0.0f;
-  }
-}
-
-bool paint_calculate_rake_rotation(UnifiedPaintSettings *ups,
-                                   Brush *brush,
-                                   const float mouse_pos[2])
-{
-  bool ok = false;
-  if ((brush->mtex.brush_angle_mode & MTEX_ANGLE_RAKE) ||
-      (brush->mask_mtex.brush_angle_mode & MTEX_ANGLE_RAKE)) {
-    const float r = RAKE_THRESHHOLD;
-    float rotation;
-
-    float dpos[2];
-    sub_v2_v2v2(dpos, ups->last_rake, mouse_pos);
-
-    if (len_squared_v2(dpos) >= r * r) {
-      rotation = atan2f(dpos[0], dpos[1]);
-
-      copy_v2_v2(ups->last_rake, mouse_pos);
-
-      ups->last_rake_angle = rotation;
-
-      paint_update_brush_rake_rotation(ups, brush, rotation);
-      ok = true;
-    }
-    /* make sure we reset here to the last rotation to avoid accumulating
-     * values in case a random rotation is also added */
-    else {
-      paint_update_brush_rake_rotation(ups, brush, ups->last_rake_angle);
-      ok = false;
-    }
-  }
-  else {
-    ups->brush_rotation = ups->brush_rotation_sec = 0.0f;
-    ok = true;
-  }
-  return ok;
-}
-
-void BKE_sculptsession_free_deformMats(SculptSession *ss)
-{
-  MEM_SAFE_FREE(ss->orig_cos);
-  MEM_SAFE_FREE(ss->deform_cos);
-  MEM_SAFE_FREE(ss->deform_imats);
-}
-
-void BKE_sculptsession_free_vwpaint_data(struct SculptSession *ss)
-{
-  struct SculptVertexPaintGeomMap *gmap = NULL;
-  if (ss->mode_type == OB_MODE_VERTEX_PAINT) {
-    gmap = &ss->mode.vpaint.gmap;
-  }
-  else if (ss->mode_type == OB_MODE_WEIGHT_PAINT) {
-    gmap = &ss->mode.wpaint.gmap;
-
-    MEM_SAFE_FREE(ss->mode.wpaint.alpha_weight);
-    if (ss->mode.wpaint.dvert_prev) {
-      BKE_defvert_array_free_elems(ss->mode.wpaint.dvert_prev, ss->totvert);
-      MEM_freeN(ss->mode.wpaint.dvert_prev);
-      ss->mode.wpaint.dvert_prev = NULL;
-    }
-  }
-  else {
-    return;
-  }
-  MEM_SAFE_FREE(gmap->vert_to_loop);
-  MEM_SAFE_FREE(gmap->vert_map_mem);
-  MEM_SAFE_FREE(gmap->vert_to_poly);
-  MEM_SAFE_FREE(gmap->poly_map_mem);
-}
-
-/**
- * Write out the sculpt dynamic-topology #BMesh to the #Mesh.
- */
-static void sculptsession_bm_to_me_update_data_only(Object *ob, bool reorder)
-{
-  SculptSession *ss = ob->sculpt;
-
-  if (ss->bm) {
-    if (ob->data) {
-      BMIter iter;
-      BMFace *efa;
-      BM_ITER_MESH (efa, &iter, ss->bm, BM_FACES_OF_MESH) {
-        BM_elem_flag_set(efa, BM_ELEM_SMOOTH, ss->bm_smooth_shading);
-      }
-      if (reorder) {
-        BM_log_mesh_elems_reorder(ss->bm, ss->bm_log);
-      }
-      BM_mesh_bm_to_me(NULL,
-                       ss->bm,
-                       ob->data,
-                       (&(struct BMeshToMeshParams){
-                           .calc_object_remap = false,
-                       }));
-    }
-  }
-}
-
-void BKE_sculptsession_bm_to_me(Object *ob, bool reorder)
-{
-  if (ob && ob->sculpt) {
-    sculptsession_bm_to_me_update_data_only(ob, reorder);
-
-    /* Ensure the objects evaluated mesh doesn't hold onto arrays
-     * now realloc'd in the mesh T34473. */
-    DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
-  }
-}
-
-static void sculptsession_free_pbvh(Object *object)
-{
-  SculptSession *ss = object->sculpt;
-
-  if (!ss) {
-    return;
-  }
-
-  if (ss->pbvh) {
-    BKE_pbvh_free(ss->pbvh);
-    ss->pbvh = NULL;
-  }
-
-  MEM_SAFE_FREE(ss->pmap);
-  MEM_SAFE_FREE(ss->pmap_mem);
-
-  MEM_SAFE_FREE(ss->epmap);
-  MEM_SAFE_FREE(ss->epmap_mem);
-
-  MEM_SAFE_FREE(ss->vemap);
-  MEM_SAFE_FREE(ss->vemap_mem);
-
-  MEM_SAFE_FREE(ss->persistent_base);
-
-  MEM_SAFE_FREE(ss->preview_vert_index_list);
-  ss->preview_vert_index_count = 0;
-
-  MEM_SAFE_FREE(ss->preview_vert_index_list);
-
-  MEM_SAFE_FREE(ss->vertex_info.connected_component);
-  MEM_SAFE_FREE(ss->vertex_info.boundary);
-
-  MEM_SAFE_FREE(ss->fake_neighbors.fake_neighbor_index);
-}
-
-void BKE_sculptsession_bm_to_me_for_render(Object *object)
-{
-  if (object && object->sculpt) {
-    if (object->sculpt->bm) {
-      /* Ensure no points to old arrays are stored in DM
-       *
-       * Apparently, we could not use DEG_id_tag_update
-       * here because this will lead to the while object
-       * surface to disappear, so we'll release DM in place.
-       */
-      BKE_object_free_derived_caches(object);
-
-      sculptsession_bm_to_me_update_data_only(object, false);
-
-      /* In contrast with sculptsession_bm_to_me no need in
-       * DAG tag update here - derived mesh was freed and
-       * old pointers are nowhere stored.
-       */
-    }
-  }
-}
-
-void BKE_sculptsession_free(Object *ob)
-{
-  if (ob && ob->sculpt) {
-    SculptSession *ss = ob->sculpt;
-
-    if (ss->bm) {
-      BKE_sculptsession_bm_to_me(ob, true);
-      BM_mesh_free(ss->bm);
-    }
-
-    sculptsession_free_pbvh(ob);
-
-    MEM_SAFE_FREE(ss->pmap);
-    MEM_SAFE_FREE(ss->pmap_mem);
-
-    MEM_SAFE_FREE(ss->epmap);
-    MEM_SAFE_FREE(ss->epmap_mem);
-
-    MEM_SAFE_FREE(ss->vemap);
-    MEM_SAFE_FREE(ss->vemap_mem);
-
-    if (ss->bm_log) {
-      BM_log_free(ss->bm_log);
-    }
-
-    if (ss->tex_pool) {
-      BKE_image_pool_free(ss->tex_pool);
-    }
-
-    MEM_SAFE_FREE(ss->orig_cos);
-    MEM_SAFE_FREE(ss->deform_cos);
-    MEM_SAFE_FREE(ss->deform_imats);
-
-    if (ss->pose_ik_chain_preview) {
-      for (int i = 0; i < ss->pose_ik_chain_preview->tot_segments; i++) {
-        MEM_SAFE_FREE(ss->pose_ik_chain_preview->segments[i].weights);
-      }
-      MEM_SAFE_FREE(ss->pose_ik_chain_preview->segments);
-      MEM_SAFE_FREE(ss->pose_ik_chain_preview);
-    }
-
-    if (ss->boundary_preview) {
-      MEM_SAFE_FREE(ss->boundary_preview->vertices);
-      MEM_SAFE_FREE(ss->boundary_preview->edges);
-      MEM_SAFE_FREE(ss->boundary_preview->distance);
-      MEM_SAFE_FREE(ss->boundary_preview->edit_info);
-      MEM_SAFE_FREE(ss->boundary_preview);
-    }
-
-    BKE_sculptsession_free_vwpaint_data(ob->sculpt);
-
-    MEM_SAFE_FREE(ss->last_paint_canvas_key);
-
-    MEM_freeN(ss);
-
-    ob->sculpt = NULL;
-  }
-}
-
-MultiresModifierData *BKE_sculpt_multires_active(const Scene *scene, Object *ob)
-{
-  Mesh *me = (Mesh *)ob->data;
-  ModifierData *md;
-  VirtualModifierData virtualModifierData;
-
-  if (ob->sculpt && ob->sculpt->bm) {
-    /* can't combine multires and dynamic topology */
-    return NULL;
-  }
-
-  if (!CustomData_get_layer(&me->ldata, CD_MDISPS)) {
-    /* multires can't work without displacement layer */
-    return NULL;
-  }
-
-  /* Weight paint operates on original vertices, and needs to treat multires as regular modifier
-   * to make it so that PBVH vertices are at the multires surface. */
-  if ((ob->mode & OB_MODE_SCULPT) == 0) {
-    return NULL;
-  }
-
-  for (md = BKE_modifiers_get_virtual_modifierlist(ob, &virtualModifierData); md; md = md->next) {
-    if (md->type == eModifierType_Multires) {
-      MultiresModifierData *mmd = (MultiresModifierData *)md;
-
-      if (!BKE_modifier_is_enabled(scene, md, eModifierMode_Realtime)) {
-        continue;
-      }
-
-      if (mmd->sculptlvl > 0 && !(mmd->flags & eMultiresModifierFlag_UseSculptBaseMesh)) {
-        return mmd;
-      }
-
-      return NULL;
-    }
-  }
-
-  return NULL;
-}
-
-/* Checks if there are any supported deformation modifiers active */
-static bool sculpt_modifiers_active(Scene *scene, Sculpt *sd, Object *ob)
-{
-  ModifierData *md;
-  Mesh *me = (Mesh *)ob->data;
-  VirtualModifierData virtualModifierData;
-
-  if (ob->sculpt->bm || BKE_sculpt_multires_active(scene, ob)) {
-    return false;
-  }
-
-  /* non-locked shape keys could be handled in the same way as deformed mesh */
-  if ((ob->shapeflag & OB_SHAPE_LOCK) == 0 && me->key && ob->shapenr) {
-    return true;
-  }
-
-  md = BKE_modifiers_get_virtual_modifierlist(ob, &virtualModifierData);
-
-  /* exception for shape keys because we can edit those */
-  for (; md; md = md->next) {
-    const ModifierTypeInfo *mti = BKE_modifier_get_info(md->type);
-    if (!BKE_modifier_is_enabled(scene, md, eModifierMode_Realtime)) {
-      continue;
-    }
-    if (md->type == eModifierType_Multires && (ob->mode & OB_MODE_SCULPT)) {
-      MultiresModifierData *mmd = (MultiresModifierData *)md;
-      if (!(mmd->flags & eMultiresModifierFlag_UseSculptBaseMesh)) {
-        continue;
-      }
-    }
-    if (md->type == eModifierType_ShapeKey) {
-      continue;
-    }
-
-    if (mti->type == eModifierTypeType_OnlyDeform) {
-      return true;
-    }
-    if ((sd->flags & SCULPT_ONLY_DEFORM) == 0) {
-      return true;
-    }
-  }
-
-  return false;
-}
-
-/**
- * \param need_mask: So that the evaluated mesh that is returned has mask data.
- */
-static void sculpt_update_object(Depsgraph *depsgraph,
-                                 Object *ob,
-                                 Mesh *me_eval,
-                                 bool need_pmap,
-                                 bool need_mask,
-                                 bool is_paint_tool)
-{
-  Scene *scene = DEG_get_input_scene(depsgraph);
-  Sculpt *sd = scene->toolsettings->sculpt;
-  SculptSession *ss = ob->sculpt;
-  const Mesh *me = BKE_object_get_original_mesh(ob);
-  MultiresModifierData *mmd = BKE_sculpt_multires_active(scene, ob);
-  const bool use_face_sets = (ob->mode & OB_MODE_SCULPT) != 0;
-
-  ss->depsgraph = depsgraph;
-
-  ss->deform_modifiers_active = sculpt_modifiers_active(scene, sd, ob);
-  ss->show_mask = (sd->flags & SCULPT_HIDE_MASK) == 0;
-  ss->show_face_sets = (sd->flags & SCULPT_HIDE_FACE_SETS) == 0;
-
-  ss->building_vp_handle = false;
-
-  ss->scene = scene;
-
-  if (need_mask) {
-    if (mmd == NULL) {
-      BLI_assert(CustomData_has_layer(&me->vdata, CD_PAINT_MASK));
-    }
-    else {
-      BLI_assert(CustomData_has_layer(&me->ldata, CD_GRID_PAINT_MASK));
-    }
-  }
-
-  ss->shapekey_active = (mmd == NULL) ? BKE_keyblock_from_object(ob) : NULL;
-
-  /* NOTE: Weight pPaint require mesh info for loop lookup, but it never uses multires code path,
-   * so no extra checks is needed here. */
-  if (mmd) {
-    ss->multires.active = true;
-    ss->multires.modifier = mmd;
-    ss->multires.level = mmd->sculptlvl;
-    ss->totvert = me_eval->totvert;
-    ss->totpoly = me_eval->totpoly;
-    ss->totfaces = me->totpoly;
-
-    /* These are assigned to the base mesh in Multires. This is needed because Face Sets operators
-     * and tools use the Face Sets data from the base mesh when Multires is active. */
-    ss->mvert = me->mvert;
-    ss->mpoly = me->mpoly;
-    ss->mloop = me->mloop;
-  }
-  else {
-    ss->totvert = me->totvert;
-    ss->totpoly = me->totpoly;
-    ss->totfaces = me->totpoly;
-    ss->mvert = me->mvert;
-    ss->mpoly = me->mpoly;
-    ss->mloop = me->mloop;
-    ss->multires.active = false;
-    ss->multires.modifier = NULL;
-    ss->multires.level = 0;
-    ss->vmask = CustomData_get_layer(&me->vdata, CD_PAINT_MASK);
-
-    CustomDataLayer *layer;
-    eAttrDomain domain;
-
-    if (BKE_pbvh_get_color_layer(me, &layer, &domain)) {
-      if (layer->type == CD_PROP_COLOR) {
-        ss->vcol = layer->data;
-      }
-      else {
-        ss->mcol = layer->data;
-      }
-
-      ss->vcol_domain = domain;
-      ss->vcol_type = layer->type;
-    }
-    else {
-      ss->vcol = NULL;
-      ss->mcol = NULL;
-
-      ss->vcol_type = -1;
-      ss->vcol_domain = ATTR_DOMAIN_NUM;
-    }
-  }
-
-  /* Sculpt Face Sets. */
-  if (use_face_sets) {
-    BLI_assert(CustomData_has_layer(&me->pdata, CD_SCULPT_FACE_SETS));
-    ss->face_sets = CustomData_get_layer(&me->pdata, CD_SCULPT_FACE_SETS);
-  }
-  else {
-    ss->face_sets = NULL;
-  }
-
-  ss->subdiv_ccg = me_eval->runtime.subdiv_ccg;
-
-  PBVH *pbvh = BKE_sculpt_object_pbvh_ensure(depsgraph, ob);
-  BLI_assert(pbvh == ss->pbvh);
-  UNUSED_VARS_NDEBUG(pbvh);
-
-  BKE_pbvh_subdiv_cgg_set(ss->pbvh, ss->subdiv_ccg);
-  BKE_pbvh_face_sets_set(ss->pbvh, ss->face_sets);
-
-  BKE_pbvh_face_sets_color_set(ss->pbvh, me->face_sets_color_seed, me->face_sets_color_default);
-
-  if (need_pmap && ob->type == OB_MESH && !ss->pmap) {
-    BKE_mesh_vert_poly_map_create(
-        &ss->pmap, &ss->pmap_mem, me->mpoly, me->mloop, me->totvert, me->totpoly, me->totloop);
-
-    if (ss->pbvh) {
-      BKE_pbvh_pmap_set(ss->pbvh, ss->pmap);
-    }
-  }
-
-  pbvh_show_mask_set(ss->pbvh, ss->show_mask);
-  pbvh_show_face_sets_set(ss->pbvh, ss->show_face_sets);
-
-  if (ss->deform_modifiers_active) {
-    if (!ss->orig_cos) {
-      int a;
-
-      BKE_sculptsession_free_deformMats(ss);
-
-      ss->orig_cos = (ss->shapekey_active) ?
-                         BKE_keyblock_convert_to_vertcos(ob, ss->shapekey_active) :
-                         BKE_mesh_vert_coords_alloc(me, NULL);
-
-      BKE_crazyspace_build_sculpt(depsgraph, scene, ob, &ss->deform_imats, &ss->deform_cos);
-      BKE_pbvh_vert_coords_apply(ss->pbvh, ss->deform_cos, me->totvert);
-
-      for (a = 0; a < me->totvert; a++) {
-        invert_m3(ss->deform_imats[a]);
-      }
-    }
-  }
-  else {
-    BKE_sculptsession_free_deformMats(ss);
-  }
-
-  if (ss->shapekey_active != NULL && ss->deform_cos == NULL) {
-    ss->deform_cos = BKE_keyblock_convert_to_vertcos(ob, ss->shapekey_active);
-  }
-
-  /* if pbvh is deformed, key block is already applied to it */
-  if (ss->shapekey_active) {
-    bool pbvh_deformed = BKE_pbvh_is_deformed(ss->pbvh);
-    if (!pbvh_deformed || ss->deform_cos == NULL) {
-      float(*vertCos)[3] = BKE_keyblock_convert_to_vertcos(ob, ss->shapekey_active);
-
-      if (vertCos) {
-        if (!pbvh_deformed) {
-          /* apply shape keys coordinates to PBVH */
-          BKE_pbvh_vert_coords_apply(ss->pbvh, vertCos, me->totvert);
-        }
-        if (ss->deform_cos == NULL) {
-          ss->deform_cos = vertCos;
-        }
-        if (vertCos != ss->deform_cos) {
-          MEM_freeN(vertCos);
-        }
-      }
-    }
-  }
-
-  if (is_paint_tool) {
-    /*
-     * We should rebuild the PBVH_pixels when painting canvas changes.
-     *
-     * The relevant changes are stored/encoded in the paint canvas key.
-     * These include the active uv map, and resolutions.
-     */
-    if (U.experimental.use_sculpt_texture_paint && ss->pbvh) {
-      char *paint_canvas_key = BKE_paint_canvas_key_get(&scene->toolsettings->paint_mode, ob);
-      if (ss->last_paint_canvas_key == NULL ||
-          !STREQ(paint_canvas_key, ss->last_paint_canvas_key)) {
-        MEM_SAFE_FREE(ss->last_paint_canvas_key);
-        ss->last_paint_canvas_key = paint_canvas_key;
-        BKE_pbvh_mark_rebuild_pixels(ss->pbvh);
-      }
-      else {
-        MEM_freeN(paint_canvas_key);
-      }
-    }
-
-    /* We could be more precise when we have access to the active tool. */
-    const bool use_paint_slots = (ob->mode & OB_MODE_SCULPT) != 0;
-    if (use_paint_slots) {
-      BKE_texpaint_slots_refresh_object(scene, ob);
-    }
-  }
-}
-
-static void sculpt_face_sets_ensure(Mesh *mesh)
-{
-  if (CustomData_has_layer(&mesh->pdata, CD_SCULPT_FACE_SETS)) {
-    return;
-  }
-
-  int *new_face_sets = CustomData_add_layer(
-      &mesh->pdata, CD_SCULPT_FACE_SETS, CD_CALLOC, NULL, mesh->totpoly);
-
-  /* Initialize the new Face Set data-layer with a default valid visible ID and set the default
-   * color to render it white. */
-  for (int i = 0; i < mesh->totpoly; i++) {
-    new_face_sets[i] = 1;
-  }
-  mesh->face_sets_color_default = 1;
-}
-
-void BKE_sculpt_update_object_before_eval(const Scene *scene, Object *ob_eval)
-{
-  /* Update before mesh evaluation in the dependency graph. */
-  SculptSession *ss = ob_eval->sculpt;
-
-  if (ss && ss->building_vp_handle == false) {
-    if (!ss->cache && !ss->filter_cache && !ss->expand_cache) {
-      /* We free pbvh on changes, except in the middle of drawing a stroke
-       * since it can't deal with changing PVBH node organization, we hope
-       * topology does not change in the meantime .. weak. */
-      sculptsession_free_pbvh(ob_eval);
-
-      BKE_sculptsession_free_deformMats(ob_eval->sculpt);
-
-      /* In vertex/weight paint, force maps to be rebuilt. */
-      BKE_sculptsession_free_vwpaint_data(ob_eval->sculpt);
-    }
-    else {
-      PBVHNode **nodes;
-      int n, totnode;
-
-      BKE_pbvh_search_gather(ss->pbvh, NULL, NULL, &nodes, &totnode);
-
-      for (n = 0; n < totnode; n++) {
-        BKE_pbvh_node_mark_update(nodes[n]);
-      }
-
-      MEM_freeN(nodes);
-    }
-  }
-
-  if (ss) {
-    Object *ob_orig = DEG_get_original_object(ob_eval);
-    Mesh *mesh = BKE_object_get_original_mesh(ob_orig);
-    MultiresModifierData *mmd = BKE_sculpt_multires_active(scene, ob_orig);
-
-    /* Ensure attribute layout is still correct. */
-    sculpt_face_sets_ensure(mesh);
-    BKE_sculpt_mask_layers_ensure(ob_orig, mmd);
-  }
-}
-
-void BKE_sculpt_update_object_after_eval(Depsgraph *depsgraph, Object *ob_eval)
-{
-  /* Update after mesh evaluation in the dependency graph, to rebuild PBVH or
-   * other data when modifiers change the mesh. */
-  Object *ob_orig = DEG_get_original_object(ob_eval);
-  Mesh *me_eval = BKE_object_get_evaluated_mesh(ob_eval);
-
-  BLI_assert(me_eval != NULL);
-  sculpt_update_object(depsgraph, ob_orig, me_eval, false, false, false);
-}
-
-void BKE_sculpt_color_layer_create_if_needed(struct Object *object)
-{
-  Mesh *orig_me = BKE_object_get_original_mesh(object);
-
-  int types[] = {CD_PROP_COLOR, CD_PROP_BYTE_COLOR};
-  bool has_color = false;
-
-  for (int i = 0; i < ARRAY_SIZE(types); i++) {
-    has_color = CustomData_has_layer(&orig_me->vdata, types[i]) ||
-                CustomData_has_layer(&orig_me->ldata, types[i]);
-
-    if (has_color) {
-      break;
-    }
-  }
-
-  if (has_color) {
-    return;
-  }
-
-  CustomData_add_layer(&orig_me->vdata, CD_PROP_COLOR, CD_DEFAULT, NULL, orig_me->totvert);
-  CustomDataLayer *layer = orig_me->vdata.layers +
-                           CustomData_get_layer_index(&orig_me->vdata, CD_PROP_COLOR);
-
-  BKE_mesh_update_customdata_pointers(orig_me, true);
-
-  BKE_id_attributes_active_color_set(&orig_me->id, layer);
-  DEG_id_tag_update(&orig_me->id, ID_RECALC_GEOMETRY_ALL_MODES);
-
-  if (object->sculpt && object->sculpt->pbvh) {
-    BKE_pbvh_update_active_vcol(object->sculpt->pbvh, orig_me);
-  }
-}
-
-void BKE_sculpt_update_object_for_edit(
-    Depsgraph *depsgraph, Object *ob_orig, bool need_pmap, bool need_mask, bool is_paint_tool)
-{
-  BLI_assert(ob_orig == DEG_get_original_object(ob_orig));
-
-  Object *ob_eval = DEG_get_evaluated_object(depsgraph, ob_orig);
-  Mesh *me_eval = BKE_object_get_evaluated_mesh(ob_eval);
-  BLI_assert(me_eval != NULL);
-
-  sculpt_update_object(depsgraph, ob_orig, me_eval, need_pmap, need_mask, is_paint_tool);
-}
-
-int BKE_sculpt_mask_layers_ensure(Object *ob, MultiresModifierData *mmd)
-{
-  const float *paint_mask;
-  Mesh *me = ob->data;
-  int ret = 0;
-
-  paint_mask = CustomData_get_layer(&me->vdata, CD_PAINT_MASK);
-
-  /* if multires is active, create a grid paint mask layer if there
-   * isn't one already */
-  if (mmd && !CustomData_has_layer(&me->ldata, CD_GRID_PAINT_MASK)) {
-    GridPaintMask *gmask;
-    int level = max_ii(1, mmd->sculptlvl);
-    int gridsize = BKE_ccg_gridsize(level);
-    int gridarea = gridsize * gridsize;
-    int i, j;
-
-    gmask = CustomData_add_layer(&me->ldata, CD_GRID_PAINT_MASK, CD_CALLOC, NULL, me->totloop);
-
-    for (i = 0; i < me->totloop; i++) {
-      GridPaintMask *gpm = &gmask[i];
-
-      gpm->level = level;
-      gpm->data = MEM_callocN(sizeof(float) * gridarea, "GridPaintMask.data");
-    }
-
-    /* if vertices already have mask, copy into multires data */
-    if (paint_mask) {
-      for (i = 0; i < me->totpoly; i++) {
-        const MPoly *p = &me->mpoly[i];
-        float avg = 0;
-
-        /* mask center */
-        for (j = 0; j < p->totloop; j++) {
-          const MLoop *l = &me->mloop[p->loopstart + j];
-          avg += paint_mask[l->v];
-        }
-        avg /= (float)p->totloop;
-
-        /* fill in multires mask corner */
-        for (j = 0; j < p->totloop; j++) {
-          GridPaintMask *gpm = &gmask[p->loopstart + j];
-          const MLoop *l = &me->mloop[p->loopstart + j];
-          const MLoop *prev = ME_POLY_LOOP_PREV(me->mloop, p, j);
-          const MLoop *next = ME_POLY_LOOP_NEXT(me->mloop, p, j);
-
-          gpm->data[0] = avg;
-          gpm->data[1] = (paint_mask[l->v] + paint_mask[next->v]) * 0.5f;
-          gpm->data[2] = (paint_mask[l->v] + paint_mask[prev->v]) * 0.5f;
-          gpm->data[3] = paint_mask[l->v];
-        }
-      }
-    }
-
-    ret |= SCULPT_MASK_LAYER_CALC_LOOP;
-  }
-
-  /* create vertex paint mask layer if there isn't one already */
-  if (!paint_mask) {
-    CustomData_add_layer(&me->vdata, CD_PAINT_MASK, CD_CALLOC, NULL, me->totvert);
-    ret |= SCULPT_MASK_LAYER_CALC_VERT;
-  }
-
-  return ret;
-}
-
-void BKE_sculpt_toolsettings_data_ensure(struct Scene *scene)
-{
-  BKE_paint_ensure(scene->toolsettings, (Paint **)&scene->toolsettings->sculpt);
-
-  Sculpt *sd = scene->toolsettings->sculpt;
-  if (!sd->detail_size) {
-    sd->detail_size = 12;
-  }
-  if (!sd->detail_percent) {
-    sd->detail_percent = 25;
-  }
-  if (sd->constant_detail == 0.0f) {
-    sd->constant_detail = 3.0f;
-  }
-
-  /* Set sane default tiling offsets */
-  if (!sd->paint.tile_offset[0]) {
-    sd->paint.tile_offset[0] = 1.0f;
-  }
-  if (!sd->paint.tile_offset[1]) {
-    sd->paint.tile_offset[1] = 1.0f;
-  }
-  if (!sd->paint.tile_offset[2]) {
-    sd->paint.tile_offset[2] = 1.0f;
-  }
-}
-
-static bool check_sculpt_object_deformed(Object *object, const bool for_construction)
-{
-  bool deformed = false;
-
-  /* Active modifiers means extra deformation, which can't be handled correct
-   * on birth of PBVH and sculpt "layer" levels, so use PBVH only for internal brush
-   * stuff and show final evaluated mesh so user would see actual object shape.
-   */
-  deformed |= object->sculpt->deform_modifiers_active;
-
-  if (for_construction) {
-    deformed |= object->sculpt->shapekey_active != NULL;
-  }
-  else {
-    /* As in case with modifiers, we can't synchronize deformation made against
-     * PBVH and non-locked keyblock, so also use PBVH only for brushes and
-     * final DM to give final result to user.
-     */
-    deformed |= object->sculpt->shapekey_active && (object->shapeflag & OB_SHAPE_LOCK) == 0;
-  }
-
-  return deformed;
-}
-
-void BKE_sculpt_face_sets_ensure_from_base_mesh_visibility(Mesh *mesh)
-{
-  const int face_sets_default_visible_id = 1;
-  const int face_sets_default_hidden_id = -(face_sets_default_visible_id + 1);
-
-  bool initialize_new_face_sets = false;
-
-  if (CustomData_has_layer(&mesh->pdata, CD_SCULPT_FACE_SETS)) {
-    /* Make everything visible. */
-    int *current_face_sets = CustomData_get_layer(&mesh->pdata, CD_SCULPT_FACE_SETS);
-    for (int i = 0; i < mesh->totpoly; i++) {
-      current_face_sets[i] = abs(current_face_sets[i]);
-    }
-  }
-  else {
-    initialize_new_face_sets = true;
-    int *new_face_sets = CustomData_add_layer(
-        &mesh->pdata, CD_SCULPT_FACE_SETS, CD_CALLOC, NULL, mesh->totpoly);
-
-    /* Initialize the new Face Set data-layer with a default valid visible ID and set the default
-     * color to render it white. */
-    for (int i = 0; i < mesh->totpoly; i++) {
-      new_face_sets[i] = face_sets_default_visible_id;
-    }
-    mesh->face_sets_color_default = face_sets_default_visible_id;
-  }
-
-  int *face_sets = CustomData_get_layer(&mesh->pdata, CD_SCULPT_FACE_SETS);
-
-  for (int i = 0; i < mesh->totpoly; i++) {
-    if (!(mesh->mpoly[i].flag & ME_HIDE)) {
-      continue;
-    }
-
-    if (initialize_new_face_sets) {
-      /* When initializing a new Face Set data-layer, assign a new hidden Face Set ID to hidden
-       * vertices. This way, we get at initial split in two Face Sets between hidden and
-       * visible vertices based on the previous mesh visibly from other mode that can be
-       * useful in some cases. */
-      face_sets[i] = face_sets_default_hidden_id;
-    }
-    else {
-      /* Otherwise, set the already existing Face Set ID to hidden. */
-      face_sets[i] = -abs(face_sets[i]);
-    }
-  }
-}
-
-void BKE_sculpt_sync_face_sets_visibility_to_base_mesh(Mesh *mesh)
-{
-  const int *face_sets = CustomData_get_layer(&mesh->pdata, CD_SCULPT_FACE_SETS);
-  if (!face_sets) {
-    return;
-  }
-
-  for (int i = 0; i < mesh->totpoly; i++) {
-    const bool is_face_set_visible = face_sets[i] >= 0;
-    SET_FLAG_FROM_TEST(mesh->mpoly[i].flag, !is_face_set_visible, ME_HIDE);
-  }
-
-  BKE_mesh_flush_hidden_from_polys(mesh);
-}
-
-void BKE_sculpt_sync_face_sets_visibility_to_grids(Mesh *mesh, SubdivCCG *subdiv_ccg)
-{
-  const int *face_sets = CustomData_get_layer(&mesh->pdata, CD_SCULPT_FACE_SETS);
-  if (!face_sets) {
-    return;
-  }
-
-  if (!subdiv_ccg) {
-    return;
-  }
-
-  CCGKey key;
-  BKE_subdiv_ccg_key_top_level(&key, subdiv_ccg);
-  for (int i = 0; i < mesh->totloop; i++) {
-    const int face_index = BKE_subdiv_ccg_grid_to_face_index(subdiv_ccg, i);
-    const bool is_hidden = (face_sets[face_index] < 0);
-
-    /* Avoid creating and modifying the grid_hidden bitmap if the base mesh face is visible and
-     * there is not bitmap for the grid. This is because missing grid_hidden implies grid is fully
-     * visible. */
-    if (is_hidden) {
-      BKE_subdiv_ccg_grid_hidden_ensure(subdiv_ccg, i);
-    }
-
-    BLI_bitmap *gh = subdiv_ccg->grid_hidden[i];
-    if (gh) {
-      BLI_bitmap_set_all(gh, is_hidden, key.grid_area);
-    }
-  }
-}
-
-void BKE_sculpt_sync_face_set_visibility(struct Mesh *mesh, struct SubdivCCG *subdiv_ccg)
-{
-  BKE_sculpt_face_sets_ensure_from_base_mesh_visibility(mesh);
-  BKE_sculpt_sync_face_sets_visibility_to_base_mesh(mesh);
-  BKE_sculpt_sync_face_sets_visibility_to_grids(mesh, subdiv_ccg);
-}
-
-void BKE_sculpt_ensure_orig_mesh_data(Scene *scene, Object *object)
-{
-  Mesh *mesh = BKE_mesh_from_object(object);
-  MultiresModifierData *mmd = BKE_sculpt_multires_active(scene, object);
-
-  BLI_assert(object->mode == OB_MODE_SCULPT);
-
-  /* Copy the current mesh visibility to the Face Sets. */
-  BKE_sculpt_face_sets_ensure_from_base_mesh_visibility(mesh);
-  if (object->sculpt != NULL) {
-    /* If a sculpt session is active, ensure we have its face-set data properly up-to-date. */
-    object->sculpt->face_sets = CustomData_get_layer(&mesh->pdata, CD_SCULPT_FACE_SETS);
-
-    /* NOTE: In theory we could add that on the fly when required by sculpt code.
-     * But this then requires proper update of depsgraph etc. For now we play safe, optimization is
-     * always possible later if it's worth it. */
-    BKE_sculpt_mask_layers_ensure(object, mmd);
-  }
-
-  /* Tessfaces aren't used and will become invalid. */
-  BKE_mesh_tessface_clear(mesh);
-
-  /* We always need to flush updates from depsgraph here, since at the very least
-   * `BKE_sculpt_face_sets_ensure_from_base_mesh_visibility()` will have updated some data layer of
-   * the mesh.
-   *
-   * All known potential sources of updates:
-   *   - Addition of, or changes to, the `CD_SCULPT_FACE_SETS` data layer
-   *     (`BKE_sculpt_face_sets_ensure_from_base_mesh_visibility`).
-   *   - Addition of a `CD_PAINT_MASK` data layer (`BKE_sculpt_mask_layers_ensure`).
-   *   - Object has any active modifier (modifier stack can be different in Sculpt mode).
-   *   - Multires:
-   *     + Differences of subdiv levels between sculpt and object modes
-   *       (`mmd->sculptlvl != mmd->lvl`).
-   *     + Addition of a `CD_GRID_PAINT_MASK` data layer (`BKE_sculpt_mask_layers_ensure`).
-   */
-  DEG_id_tag_update(&object->id, ID_RECALC_GEOMETRY);
-}
-
-static PBVH *build_pbvh_for_dynamic_topology(Object *ob)
-{
-  PBVH *pbvh = BKE_pbvh_new();
-  BKE_pbvh_build_bmesh(pbvh,
-                       ob->sculpt->bm,
-                       ob->sculpt->bm_smooth_shading,
-                       ob->sculpt->bm_log,
-                       ob->sculpt->cd_vert_node_offset,
-                       ob->sculpt->cd_face_node_offset);
-  pbvh_show_mask_set(pbvh, ob->sculpt->show_mask);
-  pbvh_show_face_sets_set(pbvh, false);
-  return pbvh;
-}
-
-static PBVH *build_pbvh_from_regular_mesh(Object *ob, Mesh *me_eval_deform, bool respect_hide)
-{
-  Mesh *me = BKE_object_get_original_mesh(ob);
-  const int looptris_num = poly_to_tri_count(me->totpoly, me->totloop);
-  PBVH *pbvh = BKE_pbvh_new();
-  BKE_pbvh_respect_hide_set(pbvh, respect_hide);
-
-  MLoopTri *looptri = MEM_malloc_arrayN(looptris_num, sizeof(*looptri), __func__);
-
-  BKE_mesh_recalc_looptri(me->mloop, me->mpoly, me->mvert, me->totloop, me->totpoly, looptri);
-
-  BKE_sculpt_sync_face_set_visibility(me, NULL);
-
-  BKE_pbvh_build_mesh(pbvh,
-                      me,
-                      me->mpoly,
-                      me->mloop,
-                      me->mvert,
-                      me->totvert,
-                      &me->vdata,
-                      &me->ldata,
-                      &me->pdata,
-                      looptri,
-                      looptris_num);
-
-  pbvh_show_mask_set(pbvh, ob->sculpt->show_mask);
-  pbvh_show_face_sets_set(pbvh, ob->sculpt->show_face_sets);
-
-  const bool is_deformed = check_sculpt_object_deformed(ob, true);
-  if (is_deformed && me_eval_deform != NULL) {
-    int totvert;
-    float(*v_cos)[3] = BKE_mesh_vert_coords_alloc(me_eval_deform, &totvert);
-    BKE_pbvh_vert_coords_apply(pbvh, v_cos, totvert);
-    MEM_freeN(v_cos);
-  }
-
-  return pbvh;
-}
-
-static PBVH *build_pbvh_from_ccg(Object *ob, SubdivCCG *subdiv_ccg, bool respect_hide)
-{
-  CCGKey key;
-  BKE_subdiv_ccg_key_top_level(&key, subdiv_ccg);
-  PBVH *pbvh = BKE_pbvh_new();
-  BKE_pbvh_respect_hide_set(pbvh, respect_hide);
-
-  Mesh *base_mesh = BKE_mesh_from_object(ob);
-  BKE_sculpt_sync_face_set_visibility(base_mesh, subdiv_ccg);
-
-  BKE_pbvh_build_grids(pbvh,
-                       subdiv_ccg->grids,
-                       subdiv_ccg->num_grids,
-                       &key,
-                       (void **)subdiv_ccg->grid_faces,
-                       subdiv_ccg->grid_flag_mats,
-                       subdiv_ccg->grid_hidden);
-  pbvh_show_mask_set(pbvh, ob->sculpt->show_mask);
-  pbvh_show_face_sets_set(pbvh, ob->sculpt->show_face_sets);
-  return pbvh;
-}
-
-PBVH *BKE_sculpt_object_pbvh_ensure(Depsgraph *depsgraph, Object *ob)
-{
-  if (ob == NULL || ob->sculpt == NULL) {
-    return NULL;
-  }
-
-  bool respect_hide = true;
-  if (ob->mode & (OB_MODE_VERTEX_PAINT | OB_MODE_WEIGHT_PAINT)) {
-    if (!(BKE_paint_select_vert_test(ob) || BKE_paint_select_face_test(ob))) {
-      respect_hide = false;
-    }
-  }
-
-  PBVH *pbvh = ob->sculpt->pbvh;
-  if (pbvh != NULL) {
-    /* NOTE: It is possible that grids were re-allocated due to modifier
-     * stack. Need to update those pointers. */
-    if (BKE_pbvh_type(pbvh) == PBVH_GRIDS) {
-      Object *object_eval = DEG_get_evaluated_object(depsgraph, ob);
-      Mesh *mesh_eval = object_eval->data;
-      SubdivCCG *subdiv_ccg = mesh_eval->runtime.subdiv_ccg;
-      if (subdiv_ccg != NULL) {
-        BKE_sculpt_bvh_update_from_ccg(pbvh, subdiv_ccg);
-      }
-    }
-
-    BKE_pbvh_update_active_vcol(pbvh, BKE_object_get_original_mesh(ob));
-    BKE_pbvh_pmap_set(pbvh, ob->sculpt->pmap);
-
-    return pbvh;
-  }
-
-  if (ob->sculpt->bm != NULL) {
-    /* Sculpting on a BMesh (dynamic-topology) gets a special PBVH. */
-    pbvh = build_pbvh_for_dynamic_topology(ob);
-  }
-  else {
-    Object *object_eval = DEG_get_evaluated_object(depsgraph, ob);
-    Mesh *mesh_eval = object_eval->data;
-    if (mesh_eval->runtime.subdiv_ccg != NULL) {
-      pbvh = build_pbvh_from_ccg(ob, mesh_eval->runtime.subdiv_ccg, respect_hide);
-    }
-    else if (ob->type == OB_MESH) {
-      Mesh *me_eval_deform = object_eval->runtime.mesh_deform_eval;
-      pbvh = build_pbvh_from_regular_mesh(ob, me_eval_deform, respect_hide);
-    }
-  }
-
-  BKE_pbvh_pmap_set(pbvh, ob->sculpt->pmap);
-
-  ob->sculpt->pbvh = pbvh;
-  return pbvh;
-}
-
-void BKE_sculpt_bvh_update_from_ccg(PBVH *pbvh, SubdivCCG *subdiv_ccg)
-{
-  BKE_pbvh_grids_update(pbvh,
-                        subdiv_ccg->grids,
-                        (void **)subdiv_ccg->grid_faces,
-                        subdiv_ccg->grid_flag_mats,
-                        subdiv_ccg->grid_hidden);
-}
-
-bool BKE_sculptsession_use_pbvh_draw(const Object *ob, const View3D *UNUSED(v3d))
-{
-  SculptSession *ss = ob->sculpt;
-  if (ss == NULL || ss->pbvh == NULL || ss->mode_type != OB_MODE_SCULPT) {
-    return false;
-  }
-
-  if (BKE_pbvh_type(ss->pbvh) == PBVH_FACES) {
-    /* Regular mesh only draws from PBVH without modifiers and shape keys. */
-
-    return !(ss->shapekey_active || ss->deform_modifiers_active);
-  }
-
-  /* Multires and dyntopo always draw directly from the PBVH. */
-  return true;
-}
-
-/* Returns the Face Set random color for rendering in the overlay given its ID and a color seed. */
-#define GOLDEN_RATIO_CONJUGATE 0.618033988749895f
-void BKE_paint_face_set_overlay_color_get(const int face_set, const int seed, uchar r_color[4])
-{
-  float rgba[4];
-  float random_mod_hue = GOLDEN_RATIO_CONJUGATE * (abs(face_set) + (seed % 10));
-  random_mod_hue = random_mod_hue - floorf(random_mod_hue);
-  const float random_mod_sat = BLI_hash_int_01(abs(face_set) + seed + 1);
-  const float random_mod_val = BLI_hash_int_01(abs(face_set) + seed + 2);
-  hsv_to_rgb(random_mod_hue,
-             0.6f + (random_mod_sat * 0.25f),
-             1.0f - (random_mod_val * 0.35f),
-             &rgba[0],
-             &rgba[1],
-             &rgba[2]);
-  rgba_float_to_uchar(r_color, rgba);
-}
diff --git a/source/blender/blenkernel/intern/paint.cc b/source/blender/blenkernel/intern/paint.cc
new file mode 100644
index 00000000000..0181c6e7eac
--- /dev/null
+++ b/source/blender/blenkernel/intern/paint.cc
@@ -0,0 +1,2887 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright 2009 by Nicholas Bishop. All rights reserved. */
+
+/** \file
+ * \ingroup bke
+ */
+
+#include 
+#include 
+
+#include "MEM_guardedalloc.h"
+
+#include "DNA_brush_types.h"
+#include "DNA_gpencil_types.h"
+#include "DNA_mesh_types.h"
+#include "DNA_meshdata_types.h"
+#include "DNA_modifier_types.h"
+#include "DNA_object_types.h"
+#include "DNA_scene_types.h"
+#include "DNA_space_types.h"
+#include "DNA_view3d_types.h"
+#include "DNA_workspace_types.h"
+
+#include "BLI_bitmap.h"
+#include "BLI_hash.h"
+#include "BLI_listbase.h"
+#include "BLI_math_vector.h"
+#include "BLI_string_utf8.h"
+#include "BLI_utildefines.h"
+
+#include "BLT_translation.h"
+
+#include "BKE_attribute.h"
+#include "BKE_attribute.hh"
+#include "BKE_brush.h"
+#include "BKE_ccg.h"
+#include "BKE_colortools.h"
+#include "BKE_context.h"
+#include "BKE_crazyspace.h"
+#include "BKE_deform.h"
+#include "BKE_gpencil.h"
+#include "BKE_idtype.h"
+#include "BKE_image.h"
+#include "BKE_key.h"
+#include "BKE_layer.h"
+#include "BKE_lib_id.h"
+#include "BKE_main.h"
+#include "BKE_material.h"
+#include "BKE_mesh.h"
+#include "BKE_mesh_mapping.h"
+#include "BKE_mesh_runtime.h"
+#include "BKE_modifier.h"
+#include "BKE_multires.h"
+#include "BKE_object.h"
+#include "BKE_paint.h"
+#include "BKE_pbvh.h"
+#include "BKE_subdiv_ccg.h"
+#include "BKE_subsurf.h"
+
+#include "DEG_depsgraph.h"
+#include "DEG_depsgraph_query.h"
+
+#include "RNA_enum_types.h"
+
+#include "BLO_read_write.h"
+
+#include "bmesh.h"
+
+static void sculpt_attribute_update_refs(Object *ob);
+static SculptAttribute *sculpt_attribute_ensure_ex(Object *ob,
+                                                   eAttrDomain domain,
+                                                   eCustomDataType proptype,
+                                                   const char *name,
+                                                   const SculptAttributeParams *params,
+                                                   PBVHType pbvhtype,
+                                                   bool flat_array_for_bmesh);
+void sculptsession_bmesh_add_layers(Object *ob);
+
+using blender::MutableSpan;
+using blender::Span;
+
+static void palette_init_data(ID *id)
+{
+  Palette *palette = (Palette *)id;
+
+  BLI_assert(MEMCMP_STRUCT_AFTER_IS_ZERO(palette, id));
+
+  /* Enable fake user by default. */
+  id_fake_user_set(&palette->id);
+}
+
+static void palette_copy_data(Main *UNUSED(bmain),
+                              ID *id_dst,
+                              const ID *id_src,
+                              const int UNUSED(flag))
+{
+  Palette *palette_dst = (Palette *)id_dst;
+  const Palette *palette_src = (const Palette *)id_src;
+
+  BLI_duplicatelist(&palette_dst->colors, &palette_src->colors);
+}
+
+static void palette_free_data(ID *id)
+{
+  Palette *palette = (Palette *)id;
+
+  BLI_freelistN(&palette->colors);
+}
+
+static void palette_blend_write(BlendWriter *writer, ID *id, const void *id_address)
+{
+  Palette *palette = (Palette *)id;
+
+  BLO_write_id_struct(writer, Palette, id_address, &palette->id);
+  BKE_id_blend_write(writer, &palette->id);
+
+  BLO_write_struct_list(writer, PaletteColor, &palette->colors);
+}
+
+static void palette_blend_read_data(BlendDataReader *reader, ID *id)
+{
+  Palette *palette = (Palette *)id;
+  BLO_read_list(reader, &palette->colors);
+}
+
+static void palette_undo_preserve(BlendLibReader *UNUSED(reader), ID *id_new, ID *id_old)
+{
+  /* Whole Palette is preserved across undo-steps, and it has no extra pointer, simple. */
+  /* NOTE: We do not care about potential internal references to self here, Palette has none. */
+  /* NOTE: We do not swap IDProperties, as dealing with potential ID pointers in those would be
+   *       fairly delicate. */
+  BKE_lib_id_swap(nullptr, id_new, id_old);
+  SWAP(IDProperty *, id_new->properties, id_old->properties);
+}
+
+IDTypeInfo IDType_ID_PAL = {
+    /* id_code */ ID_PAL,
+    /* id_filter */ FILTER_ID_PAL,
+    /* main_listbase_index */ INDEX_ID_PAL,
+    /* struct_size */ sizeof(Palette),
+    /* name */ "Palette",
+    /* name_plural */ "palettes",
+    /* translation_context */ BLT_I18NCONTEXT_ID_PALETTE,
+    /* flags */ IDTYPE_FLAGS_NO_ANIMDATA,
+    /* asset_type_info */ nullptr,
+
+    /* init_data */ palette_init_data,
+    /* copy_data */ palette_copy_data,
+    /* free_data */ palette_free_data,
+    /* make_local */ nullptr,
+    /* foreach_id */ nullptr,
+    /* foreach_cache */ nullptr,
+    /* foreach_path */ nullptr,
+    /* owner_pointer_get */ nullptr,
+
+    /* blend_write */ palette_blend_write,
+    /* blend_read_data */ palette_blend_read_data,
+    /* blend_read_lib */ nullptr,
+    /* blend_read_expand */ nullptr,
+
+    /* blend_read_undo_preserve */ palette_undo_preserve,
+
+    /* lib_override_apply_post */ nullptr,
+};
+
+static void paint_curve_copy_data(Main *UNUSED(bmain),
+                                  ID *id_dst,
+                                  const ID *id_src,
+                                  const int UNUSED(flag))
+{
+  PaintCurve *paint_curve_dst = (PaintCurve *)id_dst;
+  const PaintCurve *paint_curve_src = (const PaintCurve *)id_src;
+
+  if (paint_curve_src->tot_points != 0) {
+    paint_curve_dst->points = static_cast(
+        MEM_dupallocN(paint_curve_src->points));
+  }
+}
+
+static void paint_curve_free_data(ID *id)
+{
+  PaintCurve *paint_curve = (PaintCurve *)id;
+
+  MEM_SAFE_FREE(paint_curve->points);
+  paint_curve->tot_points = 0;
+}
+
+static void paint_curve_blend_write(BlendWriter *writer, ID *id, const void *id_address)
+{
+  PaintCurve *pc = (PaintCurve *)id;
+
+  BLO_write_id_struct(writer, PaintCurve, id_address, &pc->id);
+  BKE_id_blend_write(writer, &pc->id);
+
+  BLO_write_struct_array(writer, PaintCurvePoint, pc->tot_points, pc->points);
+}
+
+static void paint_curve_blend_read_data(BlendDataReader *reader, ID *id)
+{
+  PaintCurve *pc = (PaintCurve *)id;
+  BLO_read_data_address(reader, &pc->points);
+}
+
+IDTypeInfo IDType_ID_PC = {
+    /* id_code */ ID_PC,
+    /* id_filter */ FILTER_ID_PC,
+    /* main_listbase_index */ INDEX_ID_PC,
+    /* struct_size */ sizeof(PaintCurve),
+    /* name */ "PaintCurve",
+    /* name_plural */ "paint_curves",
+    /* translation_context */ BLT_I18NCONTEXT_ID_PAINTCURVE,
+    /* flags */ IDTYPE_FLAGS_NO_ANIMDATA,
+    /* asset_type_info */ nullptr,
+
+    /* init_data */ nullptr,
+    /* copy_data */ paint_curve_copy_data,
+    /* free_data */ paint_curve_free_data,
+    /* make_local */ nullptr,
+    /* foreach_id */ nullptr,
+    /* foreach_cache */ nullptr,
+    /* foreach_path */ nullptr,
+    /* owner_pointer_get */ nullptr,
+
+    /* blend_write */ paint_curve_blend_write,
+    /* blend_read_data */ paint_curve_blend_read_data,
+    /* blend_read_lib */ nullptr,
+    /* blend_read_expand */ nullptr,
+
+    /* blend_read_undo_preserve */ nullptr,
+
+    /* lib_override_apply_post */ nullptr,
+};
+
+const uchar PAINT_CURSOR_SCULPT[3] = {255, 100, 100};
+const uchar PAINT_CURSOR_VERTEX_PAINT[3] = {255, 255, 255};
+const uchar PAINT_CURSOR_WEIGHT_PAINT[3] = {200, 200, 255};
+const uchar PAINT_CURSOR_TEXTURE_PAINT[3] = {255, 255, 255};
+
+static ePaintOverlayControlFlags overlay_flags = (ePaintOverlayControlFlags)0;
+
+void BKE_paint_invalidate_overlay_tex(Scene *scene, ViewLayer *view_layer, const Tex *tex)
+{
+  Paint *p = BKE_paint_get_active(scene, view_layer);
+  if (!p) {
+    return;
+  }
+
+  Brush *br = p->brush;
+  if (!br) {
+    return;
+  }
+
+  if (br->mtex.tex == tex) {
+    overlay_flags |= PAINT_OVERLAY_INVALID_TEXTURE_PRIMARY;
+  }
+  if (br->mask_mtex.tex == tex) {
+    overlay_flags |= PAINT_OVERLAY_INVALID_TEXTURE_SECONDARY;
+  }
+}
+
+void BKE_paint_invalidate_cursor_overlay(Scene *scene, ViewLayer *view_layer, CurveMapping *curve)
+{
+  Paint *p = BKE_paint_get_active(scene, view_layer);
+  if (p == nullptr) {
+    return;
+  }
+
+  Brush *br = p->brush;
+  if (br && br->curve == curve) {
+    overlay_flags |= PAINT_OVERLAY_INVALID_CURVE;
+  }
+}
+
+void BKE_paint_invalidate_overlay_all(void)
+{
+  overlay_flags |= (PAINT_OVERLAY_INVALID_TEXTURE_SECONDARY |
+                    PAINT_OVERLAY_INVALID_TEXTURE_PRIMARY | PAINT_OVERLAY_INVALID_CURVE);
+}
+
+ePaintOverlayControlFlags BKE_paint_get_overlay_flags(void)
+{
+  return overlay_flags;
+}
+
+void BKE_paint_set_overlay_override(eOverlayFlags flags)
+{
+  if (flags & BRUSH_OVERLAY_OVERRIDE_MASK) {
+    if (flags & BRUSH_OVERLAY_CURSOR_OVERRIDE_ON_STROKE) {
+      overlay_flags |= PAINT_OVERLAY_OVERRIDE_CURSOR;
+    }
+    if (flags & BRUSH_OVERLAY_PRIMARY_OVERRIDE_ON_STROKE) {
+      overlay_flags |= PAINT_OVERLAY_OVERRIDE_PRIMARY;
+    }
+    if (flags & BRUSH_OVERLAY_SECONDARY_OVERRIDE_ON_STROKE) {
+      overlay_flags |= PAINT_OVERLAY_OVERRIDE_SECONDARY;
+    }
+  }
+  else {
+    overlay_flags &= ~(PAINT_OVERRIDE_MASK);
+  }
+}
+
+void BKE_paint_reset_overlay_invalid(ePaintOverlayControlFlags flag)
+{
+  overlay_flags &= ~(flag);
+}
+
+bool BKE_paint_ensure_from_paintmode(Scene *sce, ePaintMode mode)
+{
+  ToolSettings *ts = sce->toolsettings;
+  Paint **paint_ptr = nullptr;
+  /* Some paint modes don't store paint settings as pointer, for these this can be set and
+   * referenced by paint_ptr. */
+  Paint *paint_tmp = nullptr;
+
+  switch (mode) {
+    case PAINT_MODE_SCULPT:
+      paint_ptr = (Paint **)&ts->sculpt;
+      break;
+    case PAINT_MODE_VERTEX:
+      paint_ptr = (Paint **)&ts->vpaint;
+      break;
+    case PAINT_MODE_WEIGHT:
+      paint_ptr = (Paint **)&ts->wpaint;
+      break;
+    case PAINT_MODE_TEXTURE_2D:
+    case PAINT_MODE_TEXTURE_3D:
+      paint_tmp = (Paint *)&ts->imapaint;
+      paint_ptr = &paint_tmp;
+      break;
+    case PAINT_MODE_SCULPT_UV:
+      paint_ptr = (Paint **)&ts->uvsculpt;
+      break;
+    case PAINT_MODE_GPENCIL:
+      paint_ptr = (Paint **)&ts->gp_paint;
+      break;
+    case PAINT_MODE_VERTEX_GPENCIL:
+      paint_ptr = (Paint **)&ts->gp_vertexpaint;
+      break;
+    case PAINT_MODE_SCULPT_GPENCIL:
+      paint_ptr = (Paint **)&ts->gp_sculptpaint;
+      break;
+    case PAINT_MODE_WEIGHT_GPENCIL:
+      paint_ptr = (Paint **)&ts->gp_weightpaint;
+      break;
+    case PAINT_MODE_SCULPT_CURVES:
+      paint_ptr = (Paint **)&ts->curves_sculpt;
+      break;
+    case PAINT_MODE_INVALID:
+      break;
+  }
+  if (paint_ptr) {
+    BKE_paint_ensure(ts, paint_ptr);
+    return true;
+  }
+  return false;
+}
+
+Paint *BKE_paint_get_active_from_paintmode(Scene *sce, ePaintMode mode)
+{
+  if (sce) {
+    ToolSettings *ts = sce->toolsettings;
+
+    switch (mode) {
+      case PAINT_MODE_SCULPT:
+        return &ts->sculpt->paint;
+      case PAINT_MODE_VERTEX:
+        return &ts->vpaint->paint;
+      case PAINT_MODE_WEIGHT:
+        return &ts->wpaint->paint;
+      case PAINT_MODE_TEXTURE_2D:
+      case PAINT_MODE_TEXTURE_3D:
+        return &ts->imapaint.paint;
+      case PAINT_MODE_SCULPT_UV:
+        return &ts->uvsculpt->paint;
+      case PAINT_MODE_GPENCIL:
+        return &ts->gp_paint->paint;
+      case PAINT_MODE_VERTEX_GPENCIL:
+        return &ts->gp_vertexpaint->paint;
+      case PAINT_MODE_SCULPT_GPENCIL:
+        return &ts->gp_sculptpaint->paint;
+      case PAINT_MODE_WEIGHT_GPENCIL:
+        return &ts->gp_weightpaint->paint;
+      case PAINT_MODE_SCULPT_CURVES:
+        return &ts->curves_sculpt->paint;
+      case PAINT_MODE_INVALID:
+        return nullptr;
+      default:
+        return &ts->imapaint.paint;
+    }
+  }
+
+  return nullptr;
+}
+
+const EnumPropertyItem *BKE_paint_get_tool_enum_from_paintmode(ePaintMode mode)
+{
+  switch (mode) {
+    case PAINT_MODE_SCULPT:
+      return rna_enum_brush_sculpt_tool_items;
+    case PAINT_MODE_VERTEX:
+      return rna_enum_brush_vertex_tool_items;
+    case PAINT_MODE_WEIGHT:
+      return rna_enum_brush_weight_tool_items;
+    case PAINT_MODE_TEXTURE_2D:
+    case PAINT_MODE_TEXTURE_3D:
+      return rna_enum_brush_image_tool_items;
+    case PAINT_MODE_SCULPT_UV:
+      return rna_enum_brush_uv_sculpt_tool_items;
+    case PAINT_MODE_GPENCIL:
+      return rna_enum_brush_gpencil_types_items;
+    case PAINT_MODE_VERTEX_GPENCIL:
+      return rna_enum_brush_gpencil_vertex_types_items;
+    case PAINT_MODE_SCULPT_GPENCIL:
+      return rna_enum_brush_gpencil_sculpt_types_items;
+    case PAINT_MODE_WEIGHT_GPENCIL:
+      return rna_enum_brush_gpencil_weight_types_items;
+    case PAINT_MODE_SCULPT_CURVES:
+      return rna_enum_brush_curves_sculpt_tool_items;
+    case PAINT_MODE_INVALID:
+      break;
+  }
+  return nullptr;
+}
+
+const char *BKE_paint_get_tool_prop_id_from_paintmode(ePaintMode mode)
+{
+  switch (mode) {
+    case PAINT_MODE_SCULPT:
+      return "sculpt_tool";
+    case PAINT_MODE_VERTEX:
+      return "vertex_tool";
+    case PAINT_MODE_WEIGHT:
+      return "weight_tool";
+    case PAINT_MODE_TEXTURE_2D:
+    case PAINT_MODE_TEXTURE_3D:
+      return "image_tool";
+    case PAINT_MODE_SCULPT_UV:
+      return "uv_sculpt_tool";
+    case PAINT_MODE_GPENCIL:
+      return "gpencil_tool";
+    case PAINT_MODE_VERTEX_GPENCIL:
+      return "gpencil_vertex_tool";
+    case PAINT_MODE_SCULPT_GPENCIL:
+      return "gpencil_sculpt_tool";
+    case PAINT_MODE_WEIGHT_GPENCIL:
+      return "gpencil_weight_tool";
+    case PAINT_MODE_SCULPT_CURVES:
+      return "curves_sculpt_tool";
+    case PAINT_MODE_INVALID:
+      break;
+  }
+
+  /* Invalid paint mode. */
+  return nullptr;
+}
+
+Paint *BKE_paint_get_active(Scene *sce, ViewLayer *view_layer)
+{
+  if (sce && view_layer) {
+    ToolSettings *ts = sce->toolsettings;
+    BKE_view_layer_synced_ensure(sce, view_layer);
+    Object *actob = BKE_view_layer_active_object_get(view_layer);
+
+    if (actob) {
+      switch (actob->mode) {
+        case OB_MODE_SCULPT:
+          return &ts->sculpt->paint;
+        case OB_MODE_VERTEX_PAINT:
+          return &ts->vpaint->paint;
+        case OB_MODE_WEIGHT_PAINT:
+          return &ts->wpaint->paint;
+        case OB_MODE_TEXTURE_PAINT:
+          return &ts->imapaint.paint;
+        case OB_MODE_PAINT_GPENCIL:
+          return &ts->gp_paint->paint;
+        case OB_MODE_VERTEX_GPENCIL:
+          return &ts->gp_vertexpaint->paint;
+        case OB_MODE_SCULPT_GPENCIL:
+          return &ts->gp_sculptpaint->paint;
+        case OB_MODE_WEIGHT_GPENCIL:
+          return &ts->gp_weightpaint->paint;
+        case OB_MODE_SCULPT_CURVES:
+          return &ts->curves_sculpt->paint;
+        case OB_MODE_EDIT:
+          return ts->uvsculpt ? &ts->uvsculpt->paint : nullptr;
+        default:
+          break;
+      }
+    }
+
+    /* default to image paint */
+    return &ts->imapaint.paint;
+  }
+
+  return nullptr;
+}
+
+Paint *BKE_paint_get_active_from_context(const bContext *C)
+{
+  Scene *sce = CTX_data_scene(C);
+  ViewLayer *view_layer = CTX_data_view_layer(C);
+  SpaceImage *sima;
+
+  if (sce && view_layer) {
+    ToolSettings *ts = sce->toolsettings;
+    BKE_view_layer_synced_ensure(sce, view_layer);
+    Object *obact = BKE_view_layer_active_object_get(view_layer);
+
+    if ((sima = CTX_wm_space_image(C)) != nullptr) {
+      if (obact && obact->mode == OB_MODE_EDIT) {
+        if (sima->mode == SI_MODE_PAINT) {
+          return &ts->imapaint.paint;
+        }
+        if (sima->mode == SI_MODE_UV) {
+          return &ts->uvsculpt->paint;
+        }
+      }
+      else {
+        return &ts->imapaint.paint;
+      }
+    }
+    else {
+      return BKE_paint_get_active(sce, view_layer);
+    }
+  }
+
+  return nullptr;
+}
+
+ePaintMode BKE_paintmode_get_active_from_context(const bContext *C)
+{
+  Scene *sce = CTX_data_scene(C);
+  ViewLayer *view_layer = CTX_data_view_layer(C);
+  SpaceImage *sima;
+
+  if (sce && view_layer) {
+    BKE_view_layer_synced_ensure(sce, view_layer);
+    Object *obact = BKE_view_layer_active_object_get(view_layer);
+
+    if ((sima = CTX_wm_space_image(C)) != nullptr) {
+      if (obact && obact->mode == OB_MODE_EDIT) {
+        if (sima->mode == SI_MODE_PAINT) {
+          return PAINT_MODE_TEXTURE_2D;
+        }
+        if (sima->mode == SI_MODE_UV) {
+          return PAINT_MODE_SCULPT_UV;
+        }
+      }
+      else {
+        return PAINT_MODE_TEXTURE_2D;
+      }
+    }
+    else if (obact) {
+      switch (obact->mode) {
+        case OB_MODE_SCULPT:
+          return PAINT_MODE_SCULPT;
+        case OB_MODE_VERTEX_PAINT:
+          return PAINT_MODE_VERTEX;
+        case OB_MODE_WEIGHT_PAINT:
+          return PAINT_MODE_WEIGHT;
+        case OB_MODE_TEXTURE_PAINT:
+          return PAINT_MODE_TEXTURE_3D;
+        case OB_MODE_EDIT:
+          return PAINT_MODE_SCULPT_UV;
+        case OB_MODE_SCULPT_CURVES:
+          return PAINT_MODE_SCULPT_CURVES;
+        default:
+          return PAINT_MODE_TEXTURE_2D;
+      }
+    }
+    else {
+      /* default to image paint */
+      return PAINT_MODE_TEXTURE_2D;
+    }
+  }
+
+  return PAINT_MODE_INVALID;
+}
+
+ePaintMode BKE_paintmode_get_from_tool(const bToolRef *tref)
+{
+  if (tref->space_type == SPACE_VIEW3D) {
+    switch (tref->mode) {
+      case CTX_MODE_SCULPT:
+        return PAINT_MODE_SCULPT;
+      case CTX_MODE_PAINT_VERTEX:
+        return PAINT_MODE_VERTEX;
+      case CTX_MODE_PAINT_WEIGHT:
+        return PAINT_MODE_WEIGHT;
+      case CTX_MODE_PAINT_GPENCIL:
+        return PAINT_MODE_GPENCIL;
+      case CTX_MODE_PAINT_TEXTURE:
+        return PAINT_MODE_TEXTURE_3D;
+      case CTX_MODE_VERTEX_GPENCIL:
+        return PAINT_MODE_VERTEX_GPENCIL;
+      case CTX_MODE_SCULPT_GPENCIL:
+        return PAINT_MODE_SCULPT_GPENCIL;
+      case CTX_MODE_WEIGHT_GPENCIL:
+        return PAINT_MODE_WEIGHT_GPENCIL;
+      case CTX_MODE_SCULPT_CURVES:
+        return PAINT_MODE_SCULPT_CURVES;
+    }
+  }
+  else if (tref->space_type == SPACE_IMAGE) {
+    switch (tref->mode) {
+      case SI_MODE_PAINT:
+        return PAINT_MODE_TEXTURE_2D;
+      case SI_MODE_UV:
+        return PAINT_MODE_SCULPT_UV;
+    }
+  }
+
+  return PAINT_MODE_INVALID;
+}
+
+Brush *BKE_paint_brush(Paint *p)
+{
+  return (Brush *)BKE_paint_brush_for_read((const Paint *)p);
+}
+
+const Brush *BKE_paint_brush_for_read(const Paint *p)
+{
+  return p ? p->brush : nullptr;
+}
+
+void BKE_paint_brush_set(Paint *p, Brush *br)
+{
+  if (p) {
+    id_us_min((ID *)p->brush);
+    id_us_plus((ID *)br);
+    p->brush = br;
+
+    BKE_paint_toolslots_brush_update(p);
+  }
+}
+
+void BKE_paint_runtime_init(const ToolSettings *ts, Paint *paint)
+{
+  if (paint == &ts->imapaint.paint) {
+    paint->runtime.tool_offset = offsetof(Brush, imagepaint_tool);
+    paint->runtime.ob_mode = OB_MODE_TEXTURE_PAINT;
+  }
+  else if (ts->sculpt && paint == &ts->sculpt->paint) {
+    paint->runtime.tool_offset = offsetof(Brush, sculpt_tool);
+    paint->runtime.ob_mode = OB_MODE_SCULPT;
+  }
+  else if (ts->vpaint && paint == &ts->vpaint->paint) {
+    paint->runtime.tool_offset = offsetof(Brush, vertexpaint_tool);
+    paint->runtime.ob_mode = OB_MODE_VERTEX_PAINT;
+  }
+  else if (ts->wpaint && paint == &ts->wpaint->paint) {
+    paint->runtime.tool_offset = offsetof(Brush, weightpaint_tool);
+    paint->runtime.ob_mode = OB_MODE_WEIGHT_PAINT;
+  }
+  else if (ts->uvsculpt && paint == &ts->uvsculpt->paint) {
+    paint->runtime.tool_offset = offsetof(Brush, uv_sculpt_tool);
+    paint->runtime.ob_mode = OB_MODE_EDIT;
+  }
+  else if (ts->gp_paint && paint == &ts->gp_paint->paint) {
+    paint->runtime.tool_offset = offsetof(Brush, gpencil_tool);
+    paint->runtime.ob_mode = OB_MODE_PAINT_GPENCIL;
+  }
+  else if (ts->gp_vertexpaint && paint == &ts->gp_vertexpaint->paint) {
+    paint->runtime.tool_offset = offsetof(Brush, gpencil_vertex_tool);
+    paint->runtime.ob_mode = OB_MODE_VERTEX_GPENCIL;
+  }
+  else if (ts->gp_sculptpaint && paint == &ts->gp_sculptpaint->paint) {
+    paint->runtime.tool_offset = offsetof(Brush, gpencil_sculpt_tool);
+    paint->runtime.ob_mode = OB_MODE_SCULPT_GPENCIL;
+  }
+  else if (ts->gp_weightpaint && paint == &ts->gp_weightpaint->paint) {
+    paint->runtime.tool_offset = offsetof(Brush, gpencil_weight_tool);
+    paint->runtime.ob_mode = OB_MODE_WEIGHT_GPENCIL;
+  }
+  else if (ts->curves_sculpt && paint == &ts->curves_sculpt->paint) {
+    paint->runtime.tool_offset = offsetof(Brush, curves_sculpt_tool);
+    paint->runtime.ob_mode = OB_MODE_SCULPT_CURVES;
+  }
+  else {
+    BLI_assert_unreachable();
+  }
+}
+
+uint BKE_paint_get_brush_tool_offset_from_paintmode(const ePaintMode mode)
+{
+  switch (mode) {
+    case PAINT_MODE_TEXTURE_2D:
+    case PAINT_MODE_TEXTURE_3D:
+      return offsetof(Brush, imagepaint_tool);
+    case PAINT_MODE_SCULPT:
+      return offsetof(Brush, sculpt_tool);
+    case PAINT_MODE_VERTEX:
+      return offsetof(Brush, vertexpaint_tool);
+    case PAINT_MODE_WEIGHT:
+      return offsetof(Brush, weightpaint_tool);
+    case PAINT_MODE_SCULPT_UV:
+      return offsetof(Brush, uv_sculpt_tool);
+    case PAINT_MODE_GPENCIL:
+      return offsetof(Brush, gpencil_tool);
+    case PAINT_MODE_VERTEX_GPENCIL:
+      return offsetof(Brush, gpencil_vertex_tool);
+    case PAINT_MODE_SCULPT_GPENCIL:
+      return offsetof(Brush, gpencil_sculpt_tool);
+    case PAINT_MODE_WEIGHT_GPENCIL:
+      return offsetof(Brush, gpencil_weight_tool);
+    case PAINT_MODE_SCULPT_CURVES:
+      return offsetof(Brush, curves_sculpt_tool);
+    case PAINT_MODE_INVALID:
+      break; /* We don't use these yet. */
+  }
+  return 0;
+}
+
+PaintCurve *BKE_paint_curve_add(Main *bmain, const char *name)
+{
+  PaintCurve *pc = static_cast(BKE_id_new(bmain, ID_PC, name));
+  return pc;
+}
+
+Palette *BKE_paint_palette(Paint *p)
+{
+  return p ? p->palette : nullptr;
+}
+
+void BKE_paint_palette_set(Paint *p, Palette *palette)
+{
+  if (p) {
+    id_us_min((ID *)p->palette);
+    p->palette = palette;
+    id_us_plus((ID *)p->palette);
+  }
+}
+
+void BKE_paint_curve_set(Brush *br, PaintCurve *pc)
+{
+  if (br) {
+    id_us_min((ID *)br->paint_curve);
+    br->paint_curve = pc;
+    id_us_plus((ID *)br->paint_curve);
+  }
+}
+
+void BKE_paint_curve_clamp_endpoint_add_index(PaintCurve *pc, const int add_index)
+{
+  pc->add_index = (add_index || pc->tot_points == 1) ? (add_index + 1) : 0;
+}
+
+void BKE_palette_color_remove(Palette *palette, PaletteColor *color)
+{
+  if (BLI_listbase_count_at_most(&palette->colors, palette->active_color) ==
+      palette->active_color) {
+    palette->active_color--;
+  }
+
+  BLI_remlink(&palette->colors, color);
+
+  if (palette->active_color < 0 && !BLI_listbase_is_empty(&palette->colors)) {
+    palette->active_color = 0;
+  }
+
+  MEM_freeN(color);
+}
+
+void BKE_palette_clear(Palette *palette)
+{
+  BLI_freelistN(&palette->colors);
+  palette->active_color = 0;
+}
+
+Palette *BKE_palette_add(Main *bmain, const char *name)
+{
+  Palette *palette = static_cast(BKE_id_new(bmain, ID_PAL, name));
+  return palette;
+}
+
+PaletteColor *BKE_palette_color_add(Palette *palette)
+{
+  PaletteColor *color = MEM_cnew(__func__);
+  BLI_addtail(&palette->colors, color);
+  return color;
+}
+
+bool BKE_palette_is_empty(const Palette *palette)
+{
+  return BLI_listbase_is_empty(&palette->colors);
+}
+
+/* helper function to sort using qsort */
+static int palettecolor_compare_hsv(const void *a1, const void *a2)
+{
+  const tPaletteColorHSV *ps1 = static_cast(a1);
+  const tPaletteColorHSV *ps2 = static_cast(a2);
+
+  /* Hue */
+  if (ps1->h > ps2->h) {
+    return 1;
+  }
+  if (ps1->h < ps2->h) {
+    return -1;
+  }
+
+  /* Saturation. */
+  if (ps1->s > ps2->s) {
+    return 1;
+  }
+  if (ps1->s < ps2->s) {
+    return -1;
+  }
+
+  /* Value. */
+  if (1.0f - ps1->v > 1.0f - ps2->v) {
+    return 1;
+  }
+  if (1.0f - ps1->v < 1.0f - ps2->v) {
+    return -1;
+  }
+
+  return 0;
+}
+
+/* helper function to sort using qsort */
+static int palettecolor_compare_svh(const void *a1, const void *a2)
+{
+  const tPaletteColorHSV *ps1 = static_cast(a1);
+  const tPaletteColorHSV *ps2 = static_cast(a2);
+
+  /* Saturation. */
+  if (ps1->s > ps2->s) {
+    return 1;
+  }
+  if (ps1->s < ps2->s) {
+    return -1;
+  }
+
+  /* Value. */
+  if (1.0f - ps1->v > 1.0f - ps2->v) {
+    return 1;
+  }
+  if (1.0f - ps1->v < 1.0f - ps2->v) {
+    return -1;
+  }
+
+  /* Hue */
+  if (ps1->h > ps2->h) {
+    return 1;
+  }
+  if (ps1->h < ps2->h) {
+    return -1;
+  }
+
+  return 0;
+}
+
+static int palettecolor_compare_vhs(const void *a1, const void *a2)
+{
+  const tPaletteColorHSV *ps1 = static_cast(a1);
+  const tPaletteColorHSV *ps2 = static_cast(a2);
+
+  /* Value. */
+  if (1.0f - ps1->v > 1.0f - ps2->v) {
+    return 1;
+  }
+  if (1.0f - ps1->v < 1.0f - ps2->v) {
+    return -1;
+  }
+
+  /* Hue */
+  if (ps1->h > ps2->h) {
+    return 1;
+  }
+  if (ps1->h < ps2->h) {
+    return -1;
+  }
+
+  /* Saturation. */
+  if (ps1->s > ps2->s) {
+    return 1;
+  }
+  if (ps1->s < ps2->s) {
+    return -1;
+  }
+
+  return 0;
+}
+
+static int palettecolor_compare_luminance(const void *a1, const void *a2)
+{
+  const tPaletteColorHSV *ps1 = static_cast(a1);
+  const tPaletteColorHSV *ps2 = static_cast(a2);
+
+  float lumi1 = (ps1->rgb[0] + ps1->rgb[1] + ps1->rgb[2]) / 3.0f;
+  float lumi2 = (ps2->rgb[0] + ps2->rgb[1] + ps2->rgb[2]) / 3.0f;
+
+  if (lumi1 > lumi2) {
+    return -1;
+  }
+  if (lumi1 < lumi2) {
+    return 1;
+  }
+
+  return 0;
+}
+
+void BKE_palette_sort_hsv(tPaletteColorHSV *color_array, const int totcol)
+{
+  /* Sort by Hue, Saturation and Value. */
+  qsort(color_array, totcol, sizeof(tPaletteColorHSV), palettecolor_compare_hsv);
+}
+
+void BKE_palette_sort_svh(tPaletteColorHSV *color_array, const int totcol)
+{
+  /* Sort by Saturation, Value and Hue. */
+  qsort(color_array, totcol, sizeof(tPaletteColorHSV), palettecolor_compare_svh);
+}
+
+void BKE_palette_sort_vhs(tPaletteColorHSV *color_array, const int totcol)
+{
+  /* Sort by Saturation, Value and Hue. */
+  qsort(color_array, totcol, sizeof(tPaletteColorHSV), palettecolor_compare_vhs);
+}
+
+void BKE_palette_sort_luminance(tPaletteColorHSV *color_array, const int totcol)
+{
+  /* Sort by Luminance (calculated with the average, enough for sorting). */
+  qsort(color_array, totcol, sizeof(tPaletteColorHSV), palettecolor_compare_luminance);
+}
+
+bool BKE_palette_from_hash(Main *bmain, GHash *color_table, const char *name, const bool linear)
+{
+  tPaletteColorHSV *color_array = nullptr;
+  tPaletteColorHSV *col_elm = nullptr;
+  bool done = false;
+
+  const int totpal = BLI_ghash_len(color_table);
+
+  if (totpal > 0) {
+    color_array = static_cast(
+        MEM_calloc_arrayN(totpal, sizeof(tPaletteColorHSV), __func__));
+    /* Put all colors in an array. */
+    GHashIterator gh_iter;
+    int t = 0;
+    GHASH_ITER (gh_iter, color_table) {
+      const uint col = POINTER_AS_INT(BLI_ghashIterator_getValue(&gh_iter));
+      float r, g, b;
+      float h, s, v;
+      cpack_to_rgb(col, &r, &g, &b);
+      rgb_to_hsv(r, g, b, &h, &s, &v);
+
+      col_elm = &color_array[t];
+      col_elm->rgb[0] = r;
+      col_elm->rgb[1] = g;
+      col_elm->rgb[2] = b;
+      col_elm->h = h;
+      col_elm->s = s;
+      col_elm->v = v;
+      t++;
+    }
+  }
+
+  /* Create the Palette. */
+  if (totpal > 0) {
+    /* Sort by Hue and saturation. */
+    BKE_palette_sort_hsv(color_array, totpal);
+
+    Palette *palette = BKE_palette_add(bmain, name);
+    if (palette) {
+      for (int i = 0; i < totpal; i++) {
+        col_elm = &color_array[i];
+        PaletteColor *palcol = BKE_palette_color_add(palette);
+        if (palcol) {
+          copy_v3_v3(palcol->rgb, col_elm->rgb);
+          if (linear) {
+            linearrgb_to_srgb_v3_v3(palcol->rgb, palcol->rgb);
+          }
+        }
+      }
+      done = true;
+    }
+  }
+  else {
+    done = false;
+  }
+
+  if (totpal > 0) {
+    MEM_SAFE_FREE(color_array);
+  }
+
+  return done;
+}
+
+bool BKE_paint_select_face_test(Object *ob)
+{
+  return ((ob != nullptr) && (ob->type == OB_MESH) && (ob->data != nullptr) &&
+          (((Mesh *)ob->data)->editflag & ME_EDIT_PAINT_FACE_SEL) &&
+          (ob->mode & (OB_MODE_VERTEX_PAINT | OB_MODE_WEIGHT_PAINT | OB_MODE_TEXTURE_PAINT)));
+}
+
+bool BKE_paint_select_vert_test(Object *ob)
+{
+  return ((ob != nullptr) && (ob->type == OB_MESH) && (ob->data != nullptr) &&
+          (((Mesh *)ob->data)->editflag & ME_EDIT_PAINT_VERT_SEL) &&
+          (ob->mode & OB_MODE_WEIGHT_PAINT || ob->mode & OB_MODE_VERTEX_PAINT));
+}
+
+bool BKE_paint_select_elem_test(Object *ob)
+{
+  return (BKE_paint_select_vert_test(ob) || BKE_paint_select_face_test(ob));
+}
+
+bool BKE_paint_always_hide_test(Object *ob)
+{
+  return ((ob != nullptr) && (ob->type == OB_MESH) && (ob->data != nullptr) &&
+          (ob->mode & OB_MODE_WEIGHT_PAINT || ob->mode & OB_MODE_VERTEX_PAINT));
+}
+
+void BKE_paint_cavity_curve_preset(Paint *p, int preset)
+{
+  CurveMapping *cumap = nullptr;
+  CurveMap *cuma = nullptr;
+
+  if (!p->cavity_curve) {
+    p->cavity_curve = BKE_curvemapping_add(1, 0, 0, 1, 1);
+  }
+  cumap = p->cavity_curve;
+  cumap->flag &= ~CUMA_EXTEND_EXTRAPOLATE;
+  cumap->preset = preset;
+
+  cuma = cumap->cm;
+  BKE_curvemap_reset(cuma, &cumap->clipr, cumap->preset, CURVEMAP_SLOPE_POSITIVE);
+  BKE_curvemapping_changed(cumap, false);
+}
+
+eObjectMode BKE_paint_object_mode_from_paintmode(ePaintMode mode)
+{
+  switch (mode) {
+    case PAINT_MODE_SCULPT:
+      return OB_MODE_SCULPT;
+    case PAINT_MODE_VERTEX:
+      return OB_MODE_VERTEX_PAINT;
+    case PAINT_MODE_WEIGHT:
+      return OB_MODE_WEIGHT_PAINT;
+    case PAINT_MODE_TEXTURE_2D:
+    case PAINT_MODE_TEXTURE_3D:
+      return OB_MODE_TEXTURE_PAINT;
+    case PAINT_MODE_SCULPT_UV:
+      return OB_MODE_EDIT;
+    case PAINT_MODE_INVALID:
+    default:
+      return OB_MODE_OBJECT;
+  }
+}
+
+bool BKE_paint_ensure(ToolSettings *ts, Paint **r_paint)
+{
+  Paint *paint = nullptr;
+  if (*r_paint) {
+    /* Tool offset should never be 0 for initialized paint settings, so it's a reliable way to
+     * check if already initialized. */
+    if ((*r_paint)->runtime.tool_offset == 0) {
+      /* Currently only image painting is initialized this way, others have to be allocated. */
+      BLI_assert(ELEM(*r_paint, (Paint *)&ts->imapaint));
+
+      BKE_paint_runtime_init(ts, *r_paint);
+    }
+    else {
+      BLI_assert(ELEM(*r_paint,
+                      /* Cast is annoying, but prevent nullptr-pointer access. */
+                      (Paint *)ts->gp_paint,
+                      (Paint *)ts->gp_vertexpaint,
+                      (Paint *)ts->gp_sculptpaint,
+                      (Paint *)ts->gp_weightpaint,
+                      (Paint *)ts->sculpt,
+                      (Paint *)ts->vpaint,
+                      (Paint *)ts->wpaint,
+                      (Paint *)ts->uvsculpt,
+                      (Paint *)ts->curves_sculpt,
+                      (Paint *)&ts->imapaint));
+#ifdef DEBUG
+      Paint paint_test = **r_paint;
+      BKE_paint_runtime_init(ts, *r_paint);
+      /* Swap so debug doesn't hide errors when release fails. */
+      SWAP(Paint, **r_paint, paint_test);
+      BLI_assert(paint_test.runtime.ob_mode == (*r_paint)->runtime.ob_mode);
+      BLI_assert(paint_test.runtime.tool_offset == (*r_paint)->runtime.tool_offset);
+#endif
+    }
+    return true;
+  }
+
+  if (((VPaint **)r_paint == &ts->vpaint) || ((VPaint **)r_paint == &ts->wpaint)) {
+    VPaint *data = MEM_cnew(__func__);
+    paint = &data->paint;
+  }
+  else if ((Sculpt **)r_paint == &ts->sculpt) {
+    Sculpt *data = MEM_cnew(__func__);
+    paint = &data->paint;
+
+    /* Turn on X plane mirror symmetry by default. */
+    paint->symmetry_flags |= PAINT_SYMM_X;
+
+    /* Make sure at least dyntopo subdivision is enabled. */
+    data->flags |= SCULPT_DYNTOPO_SUBDIVIDE | SCULPT_DYNTOPO_COLLAPSE;
+  }
+  else if ((GpPaint **)r_paint == &ts->gp_paint) {
+    GpPaint *data = MEM_cnew(__func__);
+    paint = &data->paint;
+  }
+  else if ((GpVertexPaint **)r_paint == &ts->gp_vertexpaint) {
+    GpVertexPaint *data = MEM_cnew(__func__);
+    paint = &data->paint;
+  }
+  else if ((GpSculptPaint **)r_paint == &ts->gp_sculptpaint) {
+    GpSculptPaint *data = MEM_cnew(__func__);
+    paint = &data->paint;
+  }
+  else if ((GpWeightPaint **)r_paint == &ts->gp_weightpaint) {
+    GpWeightPaint *data = MEM_cnew(__func__);
+    paint = &data->paint;
+  }
+  else if ((UvSculpt **)r_paint == &ts->uvsculpt) {
+    UvSculpt *data = MEM_cnew(__func__);
+    paint = &data->paint;
+  }
+  else if ((CurvesSculpt **)r_paint == &ts->curves_sculpt) {
+    CurvesSculpt *data = MEM_cnew(__func__);
+    paint = &data->paint;
+  }
+  else if (*r_paint == &ts->imapaint.paint) {
+    paint = &ts->imapaint.paint;
+  }
+
+  paint->flags |= PAINT_SHOW_BRUSH;
+
+  *r_paint = paint;
+
+  BKE_paint_runtime_init(ts, paint);
+
+  return false;
+}
+
+void BKE_paint_init(Main *bmain, Scene *sce, ePaintMode mode, const uchar col[3])
+{
+  UnifiedPaintSettings *ups = &sce->toolsettings->unified_paint_settings;
+  Paint *paint = BKE_paint_get_active_from_paintmode(sce, mode);
+
+  BKE_paint_ensure_from_paintmode(sce, mode);
+
+  /* If there's no brush, create one */
+  if (PAINT_MODE_HAS_BRUSH(mode)) {
+    Brush *brush = BKE_paint_brush(paint);
+    if (brush == nullptr) {
+      eObjectMode ob_mode = BKE_paint_object_mode_from_paintmode(mode);
+      brush = BKE_brush_first_search(bmain, ob_mode);
+      if (!brush) {
+        brush = BKE_brush_add(bmain, "Brush", ob_mode);
+        id_us_min(&brush->id); /* Fake user only. */
+      }
+      BKE_paint_brush_set(paint, brush);
+    }
+  }
+
+  copy_v3_v3_uchar(paint->paint_cursor_col, col);
+  paint->paint_cursor_col[3] = 128;
+  ups->last_stroke_valid = false;
+  zero_v3(ups->average_stroke_accum);
+  ups->average_stroke_counter = 0;
+  if (!paint->cavity_curve) {
+    BKE_paint_cavity_curve_preset(paint, CURVE_PRESET_LINE);
+  }
+}
+
+void BKE_paint_free(Paint *paint)
+{
+  BKE_curvemapping_free(paint->cavity_curve);
+  MEM_SAFE_FREE(paint->tool_slots);
+}
+
+void BKE_paint_copy(Paint *src, Paint *tar, const int flag)
+{
+  tar->brush = src->brush;
+  tar->cavity_curve = BKE_curvemapping_copy(src->cavity_curve);
+  tar->tool_slots = static_cast(MEM_dupallocN(src->tool_slots));
+
+  if ((flag & LIB_ID_CREATE_NO_USER_REFCOUNT) == 0) {
+    id_us_plus((ID *)tar->brush);
+    id_us_plus((ID *)tar->palette);
+    if (src->tool_slots != nullptr) {
+      for (int i = 0; i < tar->tool_slots_len; i++) {
+        id_us_plus((ID *)tar->tool_slots[i].brush);
+      }
+    }
+  }
+}
+
+void BKE_paint_stroke_get_average(Scene *scene, Object *ob, float stroke[3])
+{
+  UnifiedPaintSettings *ups = &scene->toolsettings->unified_paint_settings;
+  if (ups->last_stroke_valid && ups->average_stroke_counter > 0) {
+    float fac = 1.0f / ups->average_stroke_counter;
+    mul_v3_v3fl(stroke, ups->average_stroke_accum, fac);
+  }
+  else {
+    copy_v3_v3(stroke, ob->obmat[3]);
+  }
+}
+
+void BKE_paint_blend_write(BlendWriter *writer, Paint *p)
+{
+  if (p->cavity_curve) {
+    BKE_curvemapping_blend_write(writer, p->cavity_curve);
+  }
+  BLO_write_struct_array(writer, PaintToolSlot, p->tool_slots_len, p->tool_slots);
+}
+
+void BKE_paint_blend_read_data(BlendDataReader *reader, const Scene *scene, Paint *p)
+{
+  if (p->num_input_samples < 1) {
+    p->num_input_samples = 1;
+  }
+
+  BLO_read_data_address(reader, &p->cavity_curve);
+  if (p->cavity_curve) {
+    BKE_curvemapping_blend_read(reader, p->cavity_curve);
+  }
+  else {
+    BKE_paint_cavity_curve_preset(p, CURVE_PRESET_LINE);
+  }
+
+  BLO_read_data_address(reader, &p->tool_slots);
+
+  /* Workaround for invalid data written in older versions. */
+  const size_t expected_size = sizeof(PaintToolSlot) * p->tool_slots_len;
+  if (p->tool_slots && MEM_allocN_len(p->tool_slots) < expected_size) {
+    MEM_freeN(p->tool_slots);
+    p->tool_slots = static_cast(MEM_callocN(expected_size, "PaintToolSlot"));
+  }
+
+  BKE_paint_runtime_init(scene->toolsettings, p);
+}
+
+void BKE_paint_blend_read_lib(BlendLibReader *reader, Scene *sce, Paint *p)
+{
+  if (p) {
+    BLO_read_id_address(reader, sce->id.lib, &p->brush);
+    for (int i = 0; i < p->tool_slots_len; i++) {
+      if (p->tool_slots[i].brush != nullptr) {
+        BLO_read_id_address(reader, sce->id.lib, &p->tool_slots[i].brush);
+      }
+    }
+    BLO_read_id_address(reader, sce->id.lib, &p->palette);
+    p->paint_cursor = nullptr;
+
+    BKE_paint_runtime_init(sce->toolsettings, p);
+  }
+}
+
+bool paint_is_face_hidden(const MLoopTri *lt, const bool *hide_poly)
+{
+  if (!hide_poly) {
+    return false;
+  }
+  return hide_poly[lt->poly];
+}
+
+bool paint_is_grid_face_hidden(const uint *grid_hidden, int gridsize, int x, int y)
+{
+  /* Skip face if any of its corners are hidden. */
+  return (BLI_BITMAP_TEST(grid_hidden, y * gridsize + x) ||
+          BLI_BITMAP_TEST(grid_hidden, y * gridsize + x + 1) ||
+          BLI_BITMAP_TEST(grid_hidden, (y + 1) * gridsize + x + 1) ||
+          BLI_BITMAP_TEST(grid_hidden, (y + 1) * gridsize + x));
+}
+
+bool paint_is_bmesh_face_hidden(BMFace *f)
+{
+  BMLoop *l_iter;
+  BMLoop *l_first;
+
+  l_iter = l_first = BM_FACE_FIRST_LOOP(f);
+  do {
+    if (BM_elem_flag_test(l_iter->v, BM_ELEM_HIDDEN)) {
+      return true;
+    }
+  } while ((l_iter = l_iter->next) != l_first);
+
+  return false;
+}
+
+float paint_grid_paint_mask(const GridPaintMask *gpm, uint level, uint x, uint y)
+{
+  int factor = BKE_ccg_factor(level, gpm->level);
+  int gridsize = BKE_ccg_gridsize(gpm->level);
+
+  return gpm->data[(y * factor) * gridsize + (x * factor)];
+}
+
+/* Threshold to move before updating the brush rotation. */
+#define RAKE_THRESHHOLD 20
+
+void paint_update_brush_rake_rotation(UnifiedPaintSettings *ups, Brush *brush, float rotation)
+{
+  if (brush->mtex.brush_angle_mode & MTEX_ANGLE_RAKE) {
+    ups->brush_rotation = rotation;
+  }
+  else {
+    ups->brush_rotation = 0.0f;
+  }
+
+  if (brush->mask_mtex.brush_angle_mode & MTEX_ANGLE_RAKE) {
+    ups->brush_rotation_sec = rotation;
+  }
+  else {
+    ups->brush_rotation_sec = 0.0f;
+  }
+}
+
+static bool paint_rake_rotation_active(const MTex &mtex)
+{
+  return mtex.tex && mtex.brush_angle_mode & MTEX_ANGLE_RAKE;
+}
+
+static bool paint_rake_rotation_active(const Brush &brush)
+{
+  return paint_rake_rotation_active(brush.mtex) || paint_rake_rotation_active(brush.mask_mtex);
+}
+
+bool paint_calculate_rake_rotation(UnifiedPaintSettings *ups,
+                                   Brush *brush,
+                                   const float mouse_pos[2])
+{
+  bool ok = false;
+  if (paint_rake_rotation_active(*brush)) {
+    const float r = RAKE_THRESHHOLD;
+    float rotation;
+
+    float dpos[2];
+    sub_v2_v2v2(dpos, ups->last_rake, mouse_pos);
+
+    if (len_squared_v2(dpos) >= r * r) {
+      rotation = atan2f(dpos[0], dpos[1]);
+
+      copy_v2_v2(ups->last_rake, mouse_pos);
+
+      ups->last_rake_angle = rotation;
+
+      paint_update_brush_rake_rotation(ups, brush, rotation);
+      ok = true;
+    }
+    /* Make sure we reset here to the last rotation to avoid accumulating
+     * values in case a random rotation is also added. */
+    else {
+      paint_update_brush_rake_rotation(ups, brush, ups->last_rake_angle);
+      ok = false;
+    }
+  }
+  else {
+    ups->brush_rotation = ups->brush_rotation_sec = 0.0f;
+    ok = true;
+  }
+  return ok;
+}
+
+void BKE_sculptsession_free_deformMats(SculptSession *ss)
+{
+  MEM_SAFE_FREE(ss->orig_cos);
+  MEM_SAFE_FREE(ss->deform_cos);
+  MEM_SAFE_FREE(ss->deform_imats);
+}
+
+void BKE_sculptsession_free_vwpaint_data(SculptSession *ss)
+{
+  SculptVertexPaintGeomMap *gmap = nullptr;
+  if (ss->mode_type == OB_MODE_VERTEX_PAINT) {
+    gmap = &ss->mode.vpaint.gmap;
+  }
+  else if (ss->mode_type == OB_MODE_WEIGHT_PAINT) {
+    gmap = &ss->mode.wpaint.gmap;
+
+    MEM_SAFE_FREE(ss->mode.wpaint.alpha_weight);
+    if (ss->mode.wpaint.dvert_prev) {
+      BKE_defvert_array_free_elems(ss->mode.wpaint.dvert_prev, ss->totvert);
+      MEM_freeN(ss->mode.wpaint.dvert_prev);
+      ss->mode.wpaint.dvert_prev = nullptr;
+    }
+  }
+  else {
+    return;
+  }
+  MEM_SAFE_FREE(gmap->vert_to_loop);
+  MEM_SAFE_FREE(gmap->vert_map_mem);
+  MEM_SAFE_FREE(gmap->vert_to_poly);
+  MEM_SAFE_FREE(gmap->poly_map_mem);
+}
+
+/**
+ * Write out the sculpt dynamic-topology #BMesh to the #Mesh.
+ */
+static void sculptsession_bm_to_me_update_data_only(Object *ob, bool reorder)
+{
+  SculptSession *ss = ob->sculpt;
+
+  if (ss->bm) {
+    if (ob->data) {
+      BMIter iter;
+      BMFace *efa;
+      BM_ITER_MESH (efa, &iter, ss->bm, BM_FACES_OF_MESH) {
+        BM_elem_flag_set(efa, BM_ELEM_SMOOTH, ss->bm_smooth_shading);
+      }
+      if (reorder) {
+        BM_log_mesh_elems_reorder(ss->bm, ss->bm_log);
+      }
+      BMeshToMeshParams params{};
+      params.calc_object_remap = false;
+      BM_mesh_bm_to_me(nullptr, ss->bm, static_cast(ob->data), ¶ms);
+    }
+  }
+}
+
+void BKE_sculptsession_bm_to_me(Object *ob, bool reorder)
+{
+  if (ob && ob->sculpt) {
+    sculptsession_bm_to_me_update_data_only(ob, reorder);
+
+    /* Ensure the objects evaluated mesh doesn't hold onto arrays
+     * now realloc'd in the mesh T34473. */
+    DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
+  }
+}
+
+static void sculptsession_free_pbvh(Object *object)
+{
+  SculptSession *ss = object->sculpt;
+
+  if (!ss) {
+    return;
+  }
+
+  if (ss->pbvh) {
+    BKE_pbvh_free(ss->pbvh);
+    ss->pbvh = nullptr;
+  }
+
+  MEM_SAFE_FREE(ss->pmap);
+  MEM_SAFE_FREE(ss->pmap_mem);
+
+  MEM_SAFE_FREE(ss->epmap);
+  MEM_SAFE_FREE(ss->epmap_mem);
+
+  MEM_SAFE_FREE(ss->vemap);
+  MEM_SAFE_FREE(ss->vemap_mem);
+
+  MEM_SAFE_FREE(ss->preview_vert_list);
+  ss->preview_vert_count = 0;
+
+  MEM_SAFE_FREE(ss->vertex_info.connected_component);
+  MEM_SAFE_FREE(ss->vertex_info.boundary);
+
+  MEM_SAFE_FREE(ss->fake_neighbors.fake_neighbor_index);
+}
+
+void BKE_sculptsession_bm_to_me_for_render(Object *object)
+{
+  if (object && object->sculpt) {
+    if (object->sculpt->bm) {
+      /* Ensure no points to old arrays are stored in DM
+       *
+       * Apparently, we could not use DEG_id_tag_update
+       * here because this will lead to the while object
+       * surface to disappear, so we'll release DM in place.
+       */
+      BKE_object_free_derived_caches(object);
+
+      sculptsession_bm_to_me_update_data_only(object, false);
+
+      /* In contrast with sculptsession_bm_to_me no need in
+       * DAG tag update here - derived mesh was freed and
+       * old pointers are nowhere stored.
+       */
+    }
+  }
+}
+
+void BKE_sculptsession_free(Object *ob)
+{
+  if (ob && ob->sculpt) {
+    SculptSession *ss = ob->sculpt;
+
+    BKE_sculpt_attribute_destroy_temporary_all(ob);
+
+    if (ss->bm) {
+      BKE_sculptsession_bm_to_me(ob, true);
+      BM_mesh_free(ss->bm);
+    }
+
+    sculptsession_free_pbvh(ob);
+
+    MEM_SAFE_FREE(ss->pmap);
+    MEM_SAFE_FREE(ss->pmap_mem);
+
+    MEM_SAFE_FREE(ss->epmap);
+    MEM_SAFE_FREE(ss->epmap_mem);
+
+    MEM_SAFE_FREE(ss->vemap);
+    MEM_SAFE_FREE(ss->vemap_mem);
+
+    if (ss->bm_log) {
+      BM_log_free(ss->bm_log);
+    }
+
+    if (ss->tex_pool) {
+      BKE_image_pool_free(ss->tex_pool);
+    }
+
+    MEM_SAFE_FREE(ss->orig_cos);
+    MEM_SAFE_FREE(ss->deform_cos);
+    MEM_SAFE_FREE(ss->deform_imats);
+
+    if (ss->pose_ik_chain_preview) {
+      for (int i = 0; i < ss->pose_ik_chain_preview->tot_segments; i++) {
+        MEM_SAFE_FREE(ss->pose_ik_chain_preview->segments[i].weights);
+      }
+      MEM_SAFE_FREE(ss->pose_ik_chain_preview->segments);
+      MEM_SAFE_FREE(ss->pose_ik_chain_preview);
+    }
+
+    if (ss->boundary_preview) {
+      MEM_SAFE_FREE(ss->boundary_preview->verts);
+      MEM_SAFE_FREE(ss->boundary_preview->edges);
+      MEM_SAFE_FREE(ss->boundary_preview->distance);
+      MEM_SAFE_FREE(ss->boundary_preview->edit_info);
+      MEM_SAFE_FREE(ss->boundary_preview);
+    }
+
+    BKE_sculptsession_free_vwpaint_data(ob->sculpt);
+
+    MEM_SAFE_FREE(ss->last_paint_canvas_key);
+
+    MEM_freeN(ss);
+
+    ob->sculpt = nullptr;
+  }
+}
+
+static MultiresModifierData *sculpt_multires_modifier_get(const Scene *scene,
+                                                          Object *ob,
+                                                          const bool auto_create_mdisps)
+{
+  Mesh *me = (Mesh *)ob->data;
+  ModifierData *md;
+  VirtualModifierData virtualModifierData;
+
+  if (ob->sculpt && ob->sculpt->bm) {
+    /* Can't combine multires and dynamic topology. */
+    return nullptr;
+  }
+
+  bool need_mdisps = false;
+
+  if (!CustomData_get_layer(&me->ldata, CD_MDISPS)) {
+    if (!auto_create_mdisps) {
+      /* Multires can't work without displacement layer. */
+      return nullptr;
+    }
+    else {
+      need_mdisps = true;
+    }
+  }
+
+  /* Weight paint operates on original vertices, and needs to treat multires as regular modifier
+   * to make it so that PBVH vertices are at the multires surface. */
+  if ((ob->mode & OB_MODE_SCULPT) == 0) {
+    return nullptr;
+  }
+
+  for (md = BKE_modifiers_get_virtual_modifierlist(ob, &virtualModifierData); md; md = md->next) {
+    if (md->type == eModifierType_Multires) {
+      MultiresModifierData *mmd = (MultiresModifierData *)md;
+
+      if (!BKE_modifier_is_enabled(scene, md, eModifierMode_Realtime)) {
+        continue;
+      }
+
+      if (mmd->sculptlvl > 0 && !(mmd->flags & eMultiresModifierFlag_UseSculptBaseMesh)) {
+        if (need_mdisps) {
+          CustomData_add_layer(&me->ldata, CD_MDISPS, CD_SET_DEFAULT, nullptr, me->totloop);
+        }
+
+        return mmd;
+      }
+
+      return nullptr;
+    }
+  }
+
+  return nullptr;
+}
+
+MultiresModifierData *BKE_sculpt_multires_active(const Scene *scene, Object *ob)
+{
+  return sculpt_multires_modifier_get(scene, ob, false);
+}
+
+/* Checks if there are any supported deformation modifiers active */
+static bool sculpt_modifiers_active(Scene *scene, Sculpt *sd, Object *ob)
+{
+  ModifierData *md;
+  Mesh *me = (Mesh *)ob->data;
+  VirtualModifierData virtualModifierData;
+
+  if (ob->sculpt->bm || BKE_sculpt_multires_active(scene, ob)) {
+    return false;
+  }
+
+  /* Non-locked shape keys could be handled in the same way as deformed mesh. */
+  if ((ob->shapeflag & OB_SHAPE_LOCK) == 0 && me->key && ob->shapenr) {
+    return true;
+  }
+
+  md = BKE_modifiers_get_virtual_modifierlist(ob, &virtualModifierData);
+
+  /* Exception for shape keys because we can edit those. */
+  for (; md; md = md->next) {
+    const ModifierTypeInfo *mti = BKE_modifier_get_info(static_cast(md->type));
+    if (!BKE_modifier_is_enabled(scene, md, eModifierMode_Realtime)) {
+      continue;
+    }
+    if (md->type == eModifierType_Multires && (ob->mode & OB_MODE_SCULPT)) {
+      MultiresModifierData *mmd = (MultiresModifierData *)md;
+      if (!(mmd->flags & eMultiresModifierFlag_UseSculptBaseMesh)) {
+        continue;
+      }
+    }
+    if (md->type == eModifierType_ShapeKey) {
+      continue;
+    }
+
+    if (mti->type == eModifierTypeType_OnlyDeform) {
+      return true;
+    }
+    if ((sd->flags & SCULPT_ONLY_DEFORM) == 0) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
+/* Helper function to keep persistent base attribute references up to
+ * date.  This is a bit more tricky since they persist across strokes.
+ */
+static void sculpt_update_persistent_base(Object *ob)
+{
+  SculptSession *ss = ob->sculpt;
+
+  ss->attrs.persistent_co = BKE_sculpt_attribute_get(
+      ob, ATTR_DOMAIN_POINT, CD_PROP_FLOAT3, SCULPT_ATTRIBUTE_NAME(persistent_co));
+  ss->attrs.persistent_no = BKE_sculpt_attribute_get(
+      ob, ATTR_DOMAIN_POINT, CD_PROP_FLOAT3, SCULPT_ATTRIBUTE_NAME(persistent_no));
+  ss->attrs.persistent_disp = BKE_sculpt_attribute_get(
+      ob, ATTR_DOMAIN_POINT, CD_PROP_FLOAT, SCULPT_ATTRIBUTE_NAME(persistent_disp));
+}
+
+static void sculpt_update_object(
+    Depsgraph *depsgraph, Object *ob, Object *ob_eval, bool need_pmap, bool is_paint_tool)
+{
+  Scene *scene = DEG_get_input_scene(depsgraph);
+  Sculpt *sd = scene->toolsettings->sculpt;
+  SculptSession *ss = ob->sculpt;
+  Mesh *me = BKE_object_get_original_mesh(ob);
+  Mesh *me_eval = BKE_object_get_evaluated_mesh(ob_eval);
+  MultiresModifierData *mmd = sculpt_multires_modifier_get(scene, ob, true);
+  const bool use_face_sets = (ob->mode & OB_MODE_SCULPT) != 0;
+
+  BLI_assert(me_eval != nullptr);
+
+  ss->depsgraph = depsgraph;
+
+  ss->deform_modifiers_active = sculpt_modifiers_active(scene, sd, ob);
+  ss->show_mask = (sd->flags & SCULPT_HIDE_MASK) == 0;
+  ss->show_face_sets = (sd->flags & SCULPT_HIDE_FACE_SETS) == 0;
+
+  ss->building_vp_handle = false;
+
+  ss->scene = scene;
+
+  ss->shapekey_active = (mmd == nullptr) ? BKE_keyblock_from_object(ob) : nullptr;
+
+  /* NOTE: Weight pPaint require mesh info for loop lookup, but it never uses multires code path,
+   * so no extra checks is needed here. */
+  if (mmd) {
+    ss->multires.active = true;
+    ss->multires.modifier = mmd;
+    ss->multires.level = mmd->sculptlvl;
+    ss->totvert = me_eval->totvert;
+    ss->totpoly = me_eval->totpoly;
+    ss->totfaces = me->totpoly;
+
+    /* These are assigned to the base mesh in Multires. This is needed because Face Sets operators
+     * and tools use the Face Sets data from the base mesh when Multires is active. */
+    ss->mvert = BKE_mesh_verts_for_write(me);
+    ss->mpoly = BKE_mesh_polys(me);
+    ss->mloop = BKE_mesh_loops(me);
+  }
+  else {
+    ss->totvert = me->totvert;
+    ss->totpoly = me->totpoly;
+    ss->totfaces = me->totpoly;
+    ss->mvert = BKE_mesh_verts_for_write(me);
+    ss->mpoly = BKE_mesh_polys(me);
+    ss->mloop = BKE_mesh_loops(me);
+    ss->multires.active = false;
+    ss->multires.modifier = nullptr;
+    ss->multires.level = 0;
+    ss->vmask = static_cast(CustomData_get_layer(&me->vdata, CD_PAINT_MASK));
+
+    CustomDataLayer *layer;
+    eAttrDomain domain;
+
+    if (BKE_pbvh_get_color_layer(me, &layer, &domain)) {
+      if (layer->type == CD_PROP_COLOR) {
+        ss->vcol = static_cast(layer->data);
+      }
+      else {
+        ss->mcol = static_cast(layer->data);
+      }
+
+      ss->vcol_domain = domain;
+      ss->vcol_type = static_cast(layer->type);
+    }
+    else {
+      ss->vcol = nullptr;
+      ss->mcol = nullptr;
+
+      ss->vcol_type = (eCustomDataType)-1;
+      ss->vcol_domain = ATTR_DOMAIN_POINT;
+    }
+  }
+
+  /* Sculpt Face Sets. */
+  if (use_face_sets) {
+    ss->face_sets = static_cast(CustomData_get_layer(&me->pdata, CD_SCULPT_FACE_SETS));
+  }
+  else {
+    ss->face_sets = nullptr;
+  }
+
+  ss->hide_poly = (bool *)CustomData_get_layer_named(&me->pdata, CD_PROP_BOOL, ".hide_poly");
+
+  ss->subdiv_ccg = me_eval->runtime.subdiv_ccg;
+
+  PBVH *pbvh = BKE_sculpt_object_pbvh_ensure(depsgraph, ob);
+  BLI_assert(pbvh == ss->pbvh);
+  UNUSED_VARS_NDEBUG(pbvh);
+
+  BKE_pbvh_subdiv_cgg_set(ss->pbvh, ss->subdiv_ccg);
+  BKE_pbvh_face_sets_set(ss->pbvh, ss->face_sets);
+  BKE_pbvh_update_hide_attributes_from_mesh(ss->pbvh);
+
+  BKE_pbvh_face_sets_color_set(ss->pbvh, me->face_sets_color_seed, me->face_sets_color_default);
+
+  sculpt_attribute_update_refs(ob);
+  sculpt_update_persistent_base(ob);
+
+  if (need_pmap && ob->type == OB_MESH && !ss->pmap) {
+    BKE_mesh_vert_poly_map_create(&ss->pmap,
+                                  &ss->pmap_mem,
+                                  BKE_mesh_polys(me),
+                                  BKE_mesh_loops(me),
+                                  me->totvert,
+                                  me->totpoly,
+                                  me->totloop);
+
+    if (ss->pbvh) {
+      BKE_pbvh_pmap_set(ss->pbvh, ss->pmap);
+    }
+  }
+
+  pbvh_show_mask_set(ss->pbvh, ss->show_mask);
+  pbvh_show_face_sets_set(ss->pbvh, ss->show_face_sets);
+
+  if (ss->deform_modifiers_active) {
+    /* Painting doesn't need crazyspace, use already evaluated mesh coordinates if possible. */
+    bool used_me_eval = false;
+
+    if (ob->mode & (OB_MODE_VERTEX_PAINT | OB_MODE_WEIGHT_PAINT)) {
+      Mesh *me_eval_deform = ob_eval->runtime.mesh_deform_eval;
+
+      /* If the fully evaluated mesh has the same topology as the deform-only version, use it.
+       * This matters because crazyspace evaluation is very restrictive and excludes even modifiers
+       * that simply recompute vertex weights (which can even include Geometry Nodes). */
+      if (me_eval_deform->polys().data() == me_eval->polys().data() &&
+          me_eval_deform->loops().data() == me_eval->loops().data() &&
+          me_eval_deform->totvert == me_eval->totvert) {
+        BKE_sculptsession_free_deformMats(ss);
+
+        BLI_assert(me_eval_deform->totvert == me->totvert);
+
+        ss->deform_cos = BKE_mesh_vert_coords_alloc(me_eval, NULL);
+        BKE_pbvh_vert_coords_apply(ss->pbvh, ss->deform_cos, me->totvert);
+
+        used_me_eval = true;
+      }
+    }
+
+    if (!ss->orig_cos && !used_me_eval) {
+      int a;
+
+      BKE_sculptsession_free_deformMats(ss);
+
+      ss->orig_cos = (ss->shapekey_active) ?
+                         BKE_keyblock_convert_to_vertcos(ob, ss->shapekey_active) :
+                         BKE_mesh_vert_coords_alloc(me, nullptr);
+
+      BKE_crazyspace_build_sculpt(depsgraph, scene, ob, &ss->deform_imats, &ss->deform_cos);
+      BKE_pbvh_vert_coords_apply(ss->pbvh, ss->deform_cos, me->totvert);
+
+      for (a = 0; a < me->totvert; a++) {
+        invert_m3(ss->deform_imats[a]);
+      }
+    }
+  }
+  else {
+    BKE_sculptsession_free_deformMats(ss);
+  }
+
+  if (ss->shapekey_active != nullptr && ss->deform_cos == nullptr) {
+    ss->deform_cos = BKE_keyblock_convert_to_vertcos(ob, ss->shapekey_active);
+  }
+
+  /* if pbvh is deformed, key block is already applied to it */
+  if (ss->shapekey_active) {
+    bool pbvh_deformed = BKE_pbvh_is_deformed(ss->pbvh);
+    if (!pbvh_deformed || ss->deform_cos == nullptr) {
+      float(*vertCos)[3] = BKE_keyblock_convert_to_vertcos(ob, ss->shapekey_active);
+
+      if (vertCos) {
+        if (!pbvh_deformed) {
+          /* apply shape keys coordinates to PBVH */
+          BKE_pbvh_vert_coords_apply(ss->pbvh, vertCos, me->totvert);
+        }
+        if (ss->deform_cos == nullptr) {
+          ss->deform_cos = vertCos;
+        }
+        if (vertCos != ss->deform_cos) {
+          MEM_freeN(vertCos);
+        }
+      }
+    }
+  }
+
+  if (is_paint_tool) {
+    /*
+     * We should rebuild the PBVH_pixels when painting canvas changes.
+     *
+     * The relevant changes are stored/encoded in the paint canvas key.
+     * These include the active uv map, and resolutions.
+     */
+    if (U.experimental.use_sculpt_texture_paint && ss->pbvh) {
+      char *paint_canvas_key = BKE_paint_canvas_key_get(&scene->toolsettings->paint_mode, ob);
+      if (ss->last_paint_canvas_key == nullptr ||
+          !STREQ(paint_canvas_key, ss->last_paint_canvas_key)) {
+        MEM_SAFE_FREE(ss->last_paint_canvas_key);
+        ss->last_paint_canvas_key = paint_canvas_key;
+        BKE_pbvh_mark_rebuild_pixels(ss->pbvh);
+      }
+      else {
+        MEM_freeN(paint_canvas_key);
+      }
+    }
+
+    /* We could be more precise when we have access to the active tool. */
+    const bool use_paint_slots = (ob->mode & OB_MODE_SCULPT) != 0;
+    if (use_paint_slots) {
+      BKE_texpaint_slots_refresh_object(scene, ob);
+    }
+  }
+}
+
+void BKE_sculpt_update_object_before_eval(Object *ob_eval)
+{
+  /* Update before mesh evaluation in the dependency graph. */
+  SculptSession *ss = ob_eval->sculpt;
+
+  if (ss && ss->building_vp_handle == false) {
+    if (!ss->cache && !ss->filter_cache && !ss->expand_cache) {
+      /* We free pbvh on changes, except in the middle of drawing a stroke
+       * since it can't deal with changing PVBH node organization, we hope
+       * topology does not change in the meantime .. weak. */
+      sculptsession_free_pbvh(ob_eval);
+
+      BKE_sculptsession_free_deformMats(ob_eval->sculpt);
+
+      /* In vertex/weight paint, force maps to be rebuilt. */
+      BKE_sculptsession_free_vwpaint_data(ob_eval->sculpt);
+    }
+    else {
+      PBVHNode **nodes;
+      int n, totnode;
+
+      BKE_pbvh_search_gather(ss->pbvh, nullptr, nullptr, &nodes, &totnode);
+
+      for (n = 0; n < totnode; n++) {
+        BKE_pbvh_node_mark_update(nodes[n]);
+      }
+
+      MEM_freeN(nodes);
+    }
+  }
+}
+
+void BKE_sculpt_update_object_after_eval(Depsgraph *depsgraph, Object *ob_eval)
+{
+  /* Update after mesh evaluation in the dependency graph, to rebuild PBVH or
+   * other data when modifiers change the mesh. */
+  Object *ob_orig = DEG_get_original_object(ob_eval);
+
+  sculpt_update_object(depsgraph, ob_orig, ob_eval, false, false);
+}
+
+void BKE_sculpt_color_layer_create_if_needed(Object *object)
+{
+  Mesh *orig_me = BKE_object_get_original_mesh(object);
+
+  int types[] = {CD_PROP_COLOR, CD_PROP_BYTE_COLOR};
+  bool has_color = false;
+
+  for (int i = 0; i < ARRAY_SIZE(types); i++) {
+    has_color = CustomData_has_layer(&orig_me->vdata, types[i]) ||
+                CustomData_has_layer(&orig_me->ldata, types[i]);
+
+    if (has_color) {
+      break;
+    }
+  }
+
+  if (has_color) {
+    return;
+  }
+
+  CustomData_add_layer(&orig_me->vdata, CD_PROP_COLOR, CD_SET_DEFAULT, nullptr, orig_me->totvert);
+  CustomDataLayer *layer = orig_me->vdata.layers +
+                           CustomData_get_layer_index(&orig_me->vdata, CD_PROP_COLOR);
+
+  BKE_mesh_tessface_clear(orig_me);
+
+  BKE_id_attributes_active_color_set(&orig_me->id, layer);
+  DEG_id_tag_update(&orig_me->id, ID_RECALC_GEOMETRY_ALL_MODES);
+
+  if (object->sculpt && object->sculpt->pbvh) {
+    BKE_pbvh_update_active_vcol(object->sculpt->pbvh, orig_me);
+  }
+}
+
+void BKE_sculpt_update_object_for_edit(
+    Depsgraph *depsgraph, Object *ob_orig, bool need_pmap, bool /*need_mask*/, bool is_paint_tool)
+{
+  BLI_assert(ob_orig == DEG_get_original_object(ob_orig));
+
+  Object *ob_eval = DEG_get_evaluated_object(depsgraph, ob_orig);
+
+  sculpt_update_object(depsgraph, ob_orig, ob_eval, need_pmap, is_paint_tool);
+}
+
+int *BKE_sculpt_face_sets_ensure(Mesh *mesh)
+{
+  using namespace blender;
+  using namespace blender::bke;
+  if (CustomData_has_layer(&mesh->pdata, CD_SCULPT_FACE_SETS)) {
+    return static_cast(CustomData_get_layer(&mesh->pdata, CD_SCULPT_FACE_SETS));
+  }
+
+  const AttributeAccessor attributes = mesh->attributes_for_write();
+  const VArray hide_poly = attributes.lookup_or_default(
+      ".hide_poly", ATTR_DOMAIN_FACE, false);
+
+  MutableSpan face_sets = {
+      static_cast(CustomData_add_layer(
+          &mesh->pdata, CD_SCULPT_FACE_SETS, CD_CONSTRUCT, nullptr, mesh->totpoly)),
+      mesh->totpoly};
+
+  face_sets.fill(1);
+  mesh->face_sets_color_default = 1;
+  return face_sets.data();
+}
+
+bool *BKE_sculpt_hide_poly_ensure(Mesh *mesh)
+{
+  if (bool *hide_poly = static_cast(
+          CustomData_get_layer_named(&mesh->pdata, CD_PROP_BOOL, ".hide_poly"))) {
+    return hide_poly;
+  }
+  return static_cast(CustomData_add_layer_named(
+      &mesh->pdata, CD_PROP_BOOL, CD_SET_DEFAULT, nullptr, mesh->totpoly, ".hide_poly"));
+}
+
+int BKE_sculpt_mask_layers_ensure(Object *ob, MultiresModifierData *mmd)
+{
+  Mesh *me = static_cast(ob->data);
+  const Span polys = me->polys();
+  const Span loops = me->loops();
+  int ret = 0;
+
+  const float *paint_mask = static_cast(
+      CustomData_get_layer(&me->vdata, CD_PAINT_MASK));
+
+  /* if multires is active, create a grid paint mask layer if there
+   * isn't one already */
+  if (mmd && !CustomData_has_layer(&me->ldata, CD_GRID_PAINT_MASK)) {
+    GridPaintMask *gmask;
+    int level = max_ii(1, mmd->sculptlvl);
+    int gridsize = BKE_ccg_gridsize(level);
+    int gridarea = gridsize * gridsize;
+    int i, j;
+
+    gmask = static_cast(CustomData_add_layer(
+        &me->ldata, CD_GRID_PAINT_MASK, CD_SET_DEFAULT, nullptr, me->totloop));
+
+    for (i = 0; i < me->totloop; i++) {
+      GridPaintMask *gpm = &gmask[i];
+
+      gpm->level = level;
+      gpm->data = static_cast(
+          MEM_callocN(sizeof(float) * gridarea, "GridPaintMask.data"));
+    }
+
+    /* if vertices already have mask, copy into multires data */
+    if (paint_mask) {
+      for (i = 0; i < me->totpoly; i++) {
+        const MPoly *p = &polys[i];
+        float avg = 0;
+
+        /* mask center */
+        for (j = 0; j < p->totloop; j++) {
+          const MLoop *l = &loops[p->loopstart + j];
+          avg += paint_mask[l->v];
+        }
+        avg /= (float)p->totloop;
+
+        /* fill in multires mask corner */
+        for (j = 0; j < p->totloop; j++) {
+          GridPaintMask *gpm = &gmask[p->loopstart + j];
+          const MLoop *l = &loops[p->loopstart + j];
+          const MLoop *prev = ME_POLY_LOOP_PREV(loops, p, j);
+          const MLoop *next = ME_POLY_LOOP_NEXT(loops, p, j);
+
+          gpm->data[0] = avg;
+          gpm->data[1] = (paint_mask[l->v] + paint_mask[next->v]) * 0.5f;
+          gpm->data[2] = (paint_mask[l->v] + paint_mask[prev->v]) * 0.5f;
+          gpm->data[3] = paint_mask[l->v];
+        }
+      }
+    }
+    /* The evaluated multires CCG must be updated to contain the new data. */
+    DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
+
+    ret |= SCULPT_MASK_LAYER_CALC_LOOP;
+  }
+
+  /* Create vertex paint mask layer if there isn't one already. */
+  if (!paint_mask) {
+    CustomData_add_layer(&me->vdata, CD_PAINT_MASK, CD_SET_DEFAULT, nullptr, me->totvert);
+    /* The evaluated mesh must be updated to contain the new data. */
+    DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
+    ret |= SCULPT_MASK_LAYER_CALC_VERT;
+  }
+
+  return ret;
+}
+
+void BKE_sculpt_toolsettings_data_ensure(Scene *scene)
+{
+  BKE_paint_ensure(scene->toolsettings, (Paint **)&scene->toolsettings->sculpt);
+
+  Sculpt *sd = scene->toolsettings->sculpt;
+  if (!sd->detail_size) {
+    sd->detail_size = 12;
+  }
+  if (!sd->detail_percent) {
+    sd->detail_percent = 25;
+  }
+  if (sd->constant_detail == 0.0f) {
+    sd->constant_detail = 3.0f;
+  }
+
+  /* Set sane default tiling offsets. */
+  if (!sd->paint.tile_offset[0]) {
+    sd->paint.tile_offset[0] = 1.0f;
+  }
+  if (!sd->paint.tile_offset[1]) {
+    sd->paint.tile_offset[1] = 1.0f;
+  }
+  if (!sd->paint.tile_offset[2]) {
+    sd->paint.tile_offset[2] = 1.0f;
+  }
+}
+
+static bool check_sculpt_object_deformed(Object *object, const bool for_construction)
+{
+  bool deformed = false;
+
+  /* Active modifiers means extra deformation, which can't be handled correct
+   * on birth of PBVH and sculpt "layer" levels, so use PBVH only for internal brush
+   * stuff and show final evaluated mesh so user would see actual object shape. */
+  deformed |= object->sculpt->deform_modifiers_active;
+
+  if (for_construction) {
+    deformed |= object->sculpt->shapekey_active != nullptr;
+  }
+  else {
+    /* As in case with modifiers, we can't synchronize deformation made against
+     * PBVH and non-locked keyblock, so also use PBVH only for brushes and
+     * final DM to give final result to user. */
+    deformed |= object->sculpt->shapekey_active && (object->shapeflag & OB_SHAPE_LOCK) == 0;
+  }
+
+  return deformed;
+}
+
+void BKE_sculpt_sync_face_visibility_to_grids(Mesh *mesh, SubdivCCG *subdiv_ccg)
+{
+  using namespace blender;
+  using namespace blender::bke;
+  if (!subdiv_ccg) {
+    return;
+  }
+
+  const AttributeAccessor attributes = mesh->attributes();
+  const VArray hide_poly = attributes.lookup_or_default(
+      ".hide_poly", ATTR_DOMAIN_FACE, false);
+  if (hide_poly.is_single() && !hide_poly.get_internal_single()) {
+    /* Nothing is hidden, so we can just remove all visibility bitmaps. */
+    for (const int i : hide_poly.index_range()) {
+      BKE_subdiv_ccg_grid_hidden_free(subdiv_ccg, i);
+    }
+    return;
+  }
+
+  const VArraySpan hide_poly_span(hide_poly);
+  CCGKey key;
+  BKE_subdiv_ccg_key_top_level(&key, subdiv_ccg);
+  for (int i = 0; i < mesh->totloop; i++) {
+    const int face_index = BKE_subdiv_ccg_grid_to_face_index(subdiv_ccg, i);
+    const bool is_hidden = hide_poly_span[face_index];
+
+    /* Avoid creating and modifying the grid_hidden bitmap if the base mesh face is visible and
+     * there is not bitmap for the grid. This is because missing grid_hidden implies grid is fully
+     * visible. */
+    if (is_hidden) {
+      BKE_subdiv_ccg_grid_hidden_ensure(subdiv_ccg, i);
+    }
+
+    BLI_bitmap *gh = subdiv_ccg->grid_hidden[i];
+    if (gh) {
+      BLI_bitmap_set_all(gh, is_hidden, key.grid_area);
+    }
+  }
+}
+
+static PBVH *build_pbvh_for_dynamic_topology(Object *ob)
+{
+  PBVH *pbvh = ob->sculpt->pbvh = BKE_pbvh_new(PBVH_BMESH);
+
+  sculptsession_bmesh_add_layers(ob);
+
+  BKE_pbvh_build_bmesh(pbvh,
+                       ob->sculpt->bm,
+                       ob->sculpt->bm_smooth_shading,
+                       ob->sculpt->bm_log,
+                       ob->sculpt->attrs.dyntopo_node_id_vertex->bmesh_cd_offset,
+                       ob->sculpt->attrs.dyntopo_node_id_face->bmesh_cd_offset);
+  pbvh_show_mask_set(pbvh, ob->sculpt->show_mask);
+  pbvh_show_face_sets_set(pbvh, false);
+  return pbvh;
+}
+
+static PBVH *build_pbvh_from_regular_mesh(Object *ob, Mesh *me_eval_deform, bool respect_hide)
+{
+  Mesh *me = BKE_object_get_original_mesh(ob);
+  const int looptris_num = poly_to_tri_count(me->totpoly, me->totloop);
+  PBVH *pbvh = BKE_pbvh_new(PBVH_FACES);
+  BKE_pbvh_respect_hide_set(pbvh, respect_hide);
+
+  MutableSpan verts = me->verts_for_write();
+  const Span polys = me->polys();
+  const Span loops = me->loops();
+
+  MLoopTri *looptri = static_cast(
+      MEM_malloc_arrayN(looptris_num, sizeof(*looptri), __func__));
+
+  BKE_mesh_recalc_looptri(
+      loops.data(), polys.data(), verts.data(), me->totloop, me->totpoly, looptri);
+
+  BKE_pbvh_build_mesh(pbvh,
+                      me,
+                      polys.data(),
+                      loops.data(),
+                      verts.data(),
+                      me->totvert,
+                      &me->vdata,
+                      &me->ldata,
+                      &me->pdata,
+                      looptri,
+                      looptris_num);
+
+  pbvh_show_mask_set(pbvh, ob->sculpt->show_mask);
+  pbvh_show_face_sets_set(pbvh, ob->sculpt->show_face_sets);
+
+  const bool is_deformed = check_sculpt_object_deformed(ob, true);
+  if (is_deformed && me_eval_deform != nullptr) {
+    int totvert;
+    float(*v_cos)[3] = BKE_mesh_vert_coords_alloc(me_eval_deform, &totvert);
+    BKE_pbvh_vert_coords_apply(pbvh, v_cos, totvert);
+    MEM_freeN(v_cos);
+  }
+
+  return pbvh;
+}
+
+static PBVH *build_pbvh_from_ccg(Object *ob, SubdivCCG *subdiv_ccg, bool respect_hide)
+{
+  CCGKey key;
+  BKE_subdiv_ccg_key_top_level(&key, subdiv_ccg);
+  PBVH *pbvh = BKE_pbvh_new(PBVH_GRIDS);
+  BKE_pbvh_respect_hide_set(pbvh, respect_hide);
+
+  Mesh *base_mesh = BKE_mesh_from_object(ob);
+  BKE_sculpt_sync_face_visibility_to_grids(base_mesh, subdiv_ccg);
+
+  BKE_pbvh_build_grids(pbvh,
+                       subdiv_ccg->grids,
+                       subdiv_ccg->num_grids,
+                       &key,
+                       (void **)subdiv_ccg->grid_faces,
+                       subdiv_ccg->grid_flag_mats,
+                       subdiv_ccg->grid_hidden);
+  pbvh_show_mask_set(pbvh, ob->sculpt->show_mask);
+  pbvh_show_face_sets_set(pbvh, ob->sculpt->show_face_sets);
+  return pbvh;
+}
+
+PBVH *BKE_sculpt_object_pbvh_ensure(Depsgraph *depsgraph, Object *ob)
+{
+  if (ob == nullptr || ob->sculpt == nullptr) {
+    return nullptr;
+  }
+
+  const bool respect_hide = true;
+
+  PBVH *pbvh = ob->sculpt->pbvh;
+  if (pbvh != nullptr) {
+    /* NOTE: It is possible that grids were re-allocated due to modifier
+     * stack. Need to update those pointers. */
+    if (BKE_pbvh_type(pbvh) == PBVH_GRIDS) {
+      Object *object_eval = DEG_get_evaluated_object(depsgraph, ob);
+      Mesh *mesh_eval = static_cast(object_eval->data);
+      SubdivCCG *subdiv_ccg = mesh_eval->runtime.subdiv_ccg;
+      if (subdiv_ccg != nullptr) {
+        BKE_sculpt_bvh_update_from_ccg(pbvh, subdiv_ccg);
+      }
+    }
+
+    BKE_pbvh_update_active_vcol(pbvh, BKE_object_get_original_mesh(ob));
+    BKE_pbvh_pmap_set(pbvh, ob->sculpt->pmap);
+
+    return pbvh;
+  }
+
+  if (ob->sculpt->bm != nullptr) {
+    /* Sculpting on a BMesh (dynamic-topology) gets a special PBVH. */
+    pbvh = build_pbvh_for_dynamic_topology(ob);
+  }
+  else {
+    Object *object_eval = DEG_get_evaluated_object(depsgraph, ob);
+    Mesh *mesh_eval = static_cast(object_eval->data);
+    if (mesh_eval->runtime.subdiv_ccg != nullptr) {
+      pbvh = build_pbvh_from_ccg(ob, mesh_eval->runtime.subdiv_ccg, respect_hide);
+    }
+    else if (ob->type == OB_MESH) {
+      Mesh *me_eval_deform = object_eval->runtime.mesh_deform_eval;
+      pbvh = build_pbvh_from_regular_mesh(ob, me_eval_deform, respect_hide);
+    }
+  }
+
+  BKE_pbvh_pmap_set(pbvh, ob->sculpt->pmap);
+
+  ob->sculpt->pbvh = pbvh;
+  return pbvh;
+}
+
+void BKE_sculpt_bvh_update_from_ccg(PBVH *pbvh, SubdivCCG *subdiv_ccg)
+{
+  BKE_pbvh_grids_update(pbvh,
+                        subdiv_ccg->grids,
+                        (void **)subdiv_ccg->grid_faces,
+                        subdiv_ccg->grid_flag_mats,
+                        subdiv_ccg->grid_hidden);
+}
+
+bool BKE_sculptsession_use_pbvh_draw(const Object *ob, const View3D *UNUSED(v3d))
+{
+  SculptSession *ss = ob->sculpt;
+  if (ss == nullptr || ss->pbvh == nullptr || ss->mode_type != OB_MODE_SCULPT) {
+    return false;
+  }
+
+  if (BKE_pbvh_type(ss->pbvh) == PBVH_FACES) {
+    /* Regular mesh only draws from PBVH without modifiers and shape keys. */
+
+    return !(ss->shapekey_active || ss->deform_modifiers_active);
+  }
+
+  /* Multires and dyntopo always draw directly from the PBVH. */
+  return true;
+}
+
+/* Returns the Face Set random color for rendering in the overlay given its ID and a color seed. */
+#define GOLDEN_RATIO_CONJUGATE 0.618033988749895f
+void BKE_paint_face_set_overlay_color_get(const int face_set, const int seed, uchar r_color[4])
+{
+  float rgba[4];
+  float random_mod_hue = GOLDEN_RATIO_CONJUGATE * (face_set + (seed % 10));
+  random_mod_hue = random_mod_hue - floorf(random_mod_hue);
+  const float random_mod_sat = BLI_hash_int_01(face_set + seed + 1);
+  const float random_mod_val = BLI_hash_int_01(face_set + seed + 2);
+  hsv_to_rgb(random_mod_hue,
+             0.6f + (random_mod_sat * 0.25f),
+             1.0f - (random_mod_val * 0.35f),
+             &rgba[0],
+             &rgba[1],
+             &rgba[2]);
+  rgba_float_to_uchar(r_color, rgba);
+}
+
+int BKE_sculptsession_vertex_count(const SculptSession *ss)
+{
+  switch (BKE_pbvh_type(ss->pbvh)) {
+    case PBVH_FACES:
+      return ss->totvert;
+    case PBVH_BMESH:
+      return BM_mesh_elem_count(ss->bm, BM_VERT);
+    case PBVH_GRIDS:
+      return BKE_pbvh_get_grid_num_verts(ss->pbvh);
+  }
+
+  return 0;
+}
+
+/** Returns pointer to a CustomData associated with a given domain, if
+ * one exists.  If not nullptr is returned (this may happen with e.g.
+ * multires and ATTR_DOMAIN_POINT).
+ */
+static CustomData *sculpt_get_cdata(Object *ob, eAttrDomain domain)
+{
+  SculptSession *ss = ob->sculpt;
+
+  if (ss->bm) {
+    switch (domain) {
+      case ATTR_DOMAIN_POINT:
+        return &ss->bm->vdata;
+      case ATTR_DOMAIN_FACE:
+        return &ss->bm->pdata;
+      default:
+        BLI_assert_unreachable();
+        return NULL;
+    }
+  }
+  else {
+    Mesh *me = BKE_object_get_original_mesh(ob);
+
+    switch (domain) {
+      case ATTR_DOMAIN_POINT:
+        /* Cannot get vertex domain for multires grids. */
+        if (ss->pbvh && BKE_pbvh_type(ss->pbvh) == PBVH_GRIDS) {
+          return nullptr;
+        }
+
+        return &me->vdata;
+      case ATTR_DOMAIN_FACE:
+        return &me->pdata;
+      default:
+        BLI_assert_unreachable();
+        return NULL;
+    }
+  }
+}
+
+static int sculpt_attr_elem_count_get(Object *ob, eAttrDomain domain)
+{
+  SculptSession *ss = ob->sculpt;
+
+  switch (domain) {
+    case ATTR_DOMAIN_POINT:
+      return BKE_sculptsession_vertex_count(ss);
+      break;
+    case ATTR_DOMAIN_FACE:
+      return ss->totfaces;
+      break;
+    default:
+      BLI_assert_unreachable();
+      return 0;
+  }
+}
+
+static bool sculpt_attribute_create(SculptSession *ss,
+                                    Object *ob,
+                                    eAttrDomain domain,
+                                    eCustomDataType proptype,
+                                    const char *name,
+                                    SculptAttribute *out,
+                                    const SculptAttributeParams *params,
+                                    PBVHType pbvhtype,
+                                    bool flat_array_for_bmesh)
+{
+  Mesh *me = BKE_object_get_original_mesh(ob);
+
+  bool simple_array = params->simple_array;
+  bool permanent = params->permanent;
+
+  out->params = *params;
+  out->proptype = proptype;
+  out->domain = domain;
+  BLI_strncpy_utf8(out->name, name, sizeof(out->name));
+
+  /* Force non-CustomData simple_array mode if not PBVH_FACES. */
+  if (pbvhtype == PBVH_GRIDS || (pbvhtype == PBVH_BMESH && flat_array_for_bmesh)) {
+    if (permanent) {
+      printf(
+          "%s: error: tried to make permanent customdata in multires or bmesh mode; will make "
+          "local "
+          "array "
+          "instead.\n",
+          __func__);
+      permanent = (out->params.permanent = false);
+    }
+
+    simple_array = (out->params.simple_array = true);
+  }
+
+  BLI_assert(!(simple_array && permanent));
+
+  int totelem = sculpt_attr_elem_count_get(ob, domain);
+
+  if (simple_array) {
+    int elemsize = CustomData_sizeof(proptype);
+
+    out->data = MEM_calloc_arrayN(totelem, elemsize, __func__);
+
+    out->data_for_bmesh = ss->bm != NULL;
+    out->bmesh_cd_offset = -1;
+    out->layer = NULL;
+    out->elem_size = elemsize;
+    out->used = true;
+    out->elem_num = totelem;
+
+    return true;
+  }
+
+  switch (BKE_pbvh_type(ss->pbvh)) {
+    case PBVH_BMESH: {
+      CustomData *cdata = NULL;
+      out->data_for_bmesh = true;
+
+      switch (domain) {
+        case ATTR_DOMAIN_POINT:
+          cdata = &ss->bm->vdata;
+          break;
+        case ATTR_DOMAIN_FACE:
+          cdata = &ss->bm->pdata;
+          break;
+        default:
+          out->used = false;
+          return false;
+      }
+
+      BLI_assert(CustomData_get_named_layer_index(cdata, proptype, name) == -1);
+
+      BM_data_layer_add_named(ss->bm, cdata, proptype, name);
+      int index = CustomData_get_named_layer_index(cdata, proptype, name);
+
+      if (!permanent) {
+        cdata->layers[index].flag |= CD_FLAG_TEMPORARY | CD_FLAG_NOCOPY;
+      }
+
+      out->data = NULL;
+      out->layer = cdata->layers + index;
+      out->bmesh_cd_offset = out->layer->offset;
+      out->elem_size = CustomData_sizeof(proptype);
+      break;
+    }
+    case PBVH_FACES: {
+      CustomData *cdata = NULL;
+
+      out->data_for_bmesh = false;
+
+      switch (domain) {
+        case ATTR_DOMAIN_POINT:
+          cdata = &me->vdata;
+          break;
+        case ATTR_DOMAIN_FACE:
+          cdata = &me->pdata;
+          break;
+        default:
+          out->used = false;
+          return false;
+      }
+
+      BLI_assert(CustomData_get_named_layer_index(cdata, proptype, name) == -1);
+
+      CustomData_add_layer_named(cdata, proptype, CD_SET_DEFAULT, NULL, totelem, name);
+      int index = CustomData_get_named_layer_index(cdata, proptype, name);
+
+      if (!permanent) {
+        cdata->layers[index].flag |= CD_FLAG_TEMPORARY | CD_FLAG_NOCOPY;
+      }
+
+      out->data = NULL;
+      out->layer = cdata->layers + index;
+      out->bmesh_cd_offset = -1;
+      out->data = out->layer->data;
+      out->elem_size = CustomData_get_elem_size(out->layer);
+
+      break;
+    }
+    case PBVH_GRIDS: {
+      /* GRIDS should have been handled as simple arrays. */
+      BLI_assert_unreachable();
+      break;
+    }
+    default:
+      BLI_assert_unreachable();
+      break;
+  }
+
+  out->used = true;
+  out->elem_num = totelem;
+
+  return true;
+}
+
+static bool sculpt_attr_update(Object *ob, SculptAttribute *attr)
+{
+  SculptSession *ss = ob->sculpt;
+  int elem_num = sculpt_attr_elem_count_get(ob, attr->domain);
+
+  bool bad = false;
+
+  if (attr->params.simple_array) {
+    bad = attr->elem_num != elem_num;
+
+    if (bad) {
+      MEM_SAFE_FREE(attr->data);
+    }
+  }
+  else {
+    CustomData *cdata = sculpt_get_cdata(ob, attr->domain);
+
+    if (cdata) {
+      int layer_index = CustomData_get_named_layer_index(cdata, attr->proptype, attr->name);
+
+      if (layer_index != -1 && attr->data_for_bmesh) {
+        attr->bmesh_cd_offset = cdata->layers[layer_index].offset;
+      }
+      else {
+        bad = true;
+      }
+    }
+  }
+
+  if (bad) {
+    sculpt_attribute_create(ss,
+                            ob,
+                            attr->domain,
+                            attr->proptype,
+                            attr->name,
+                            attr,
+                            &attr->params,
+                            BKE_pbvh_type(ss->pbvh),
+                            true);
+  }
+
+  return bad;
+}
+
+static SculptAttribute *sculpt_get_cached_layer(SculptSession *ss,
+                                                eAttrDomain domain,
+                                                eCustomDataType proptype,
+                                                const char *name)
+{
+  for (int i = 0; i < SCULPT_MAX_ATTRIBUTES; i++) {
+    SculptAttribute *attr = ss->temp_attributes + i;
+
+    if (attr->used && STREQ(attr->name, name) && attr->proptype == proptype &&
+        attr->domain == domain) {
+
+      return attr;
+    }
+  }
+
+  return NULL;
+}
+
+bool BKE_sculpt_attribute_exists(Object *ob,
+                                 eAttrDomain domain,
+                                 eCustomDataType proptype,
+                                 const char *name)
+{
+  SculptSession *ss = ob->sculpt;
+  SculptAttribute *attr = sculpt_get_cached_layer(ss, domain, proptype, name);
+
+  if (attr) {
+    return true;
+  }
+
+  CustomData *cdata = sculpt_get_cdata(ob, domain);
+  return CustomData_get_named_layer_index(cdata, proptype, name) != -1;
+
+  return false;
+}
+
+static SculptAttribute *sculpt_alloc_attr(SculptSession *ss)
+{
+  for (int i = 0; i < SCULPT_MAX_ATTRIBUTES; i++) {
+    if (!ss->temp_attributes[i].used) {
+      memset((void *)(ss->temp_attributes + i), 0, sizeof(SculptAttribute));
+      ss->temp_attributes[i].used = true;
+
+      return ss->temp_attributes + i;
+    }
+  }
+
+  BLI_assert_unreachable();
+  return NULL;
+}
+
+SculptAttribute *BKE_sculpt_attribute_get(struct Object *ob,
+                                          eAttrDomain domain,
+                                          eCustomDataType proptype,
+                                          const char *name)
+{
+  SculptSession *ss = ob->sculpt;
+
+  /* See if attribute is cached in ss->temp_attributes. */
+  SculptAttribute *attr = sculpt_get_cached_layer(ss, domain, proptype, name);
+
+  if (attr) {
+    sculpt_attr_update(ob, attr);
+    return attr;
+  }
+
+  /* Does attribute exist in CustomData layout? */
+  CustomData *cdata = sculpt_get_cdata(ob, domain);
+  if (cdata) {
+    int index = CustomData_get_named_layer_index(cdata, proptype, name);
+
+    if (index != -1) {
+      int totelem = 0;
+
+      switch (domain) {
+        case ATTR_DOMAIN_POINT:
+          totelem = BKE_sculptsession_vertex_count(ss);
+          break;
+        case ATTR_DOMAIN_FACE:
+          totelem = ss->totfaces;
+          break;
+        default:
+          BLI_assert_unreachable();
+          break;
+      }
+
+      attr = sculpt_alloc_attr(ss);
+
+      attr->used = true;
+      attr->proptype = proptype;
+      attr->data = cdata->layers[index].data;
+      attr->bmesh_cd_offset = cdata->layers[index].offset;
+      attr->elem_num = totelem;
+      attr->layer = cdata->layers + index;
+      attr->elem_size = CustomData_get_elem_size(attr->layer);
+
+      BLI_strncpy_utf8(attr->name, name, sizeof(attr->name));
+      return attr;
+    }
+  }
+
+  return NULL;
+}
+
+static SculptAttribute *sculpt_attribute_ensure_ex(Object *ob,
+                                                   eAttrDomain domain,
+                                                   eCustomDataType proptype,
+                                                   const char *name,
+                                                   const SculptAttributeParams *params,
+                                                   PBVHType pbvhtype,
+                                                   bool flat_array_for_bmesh)
+{
+  SculptSession *ss = ob->sculpt;
+  SculptAttribute *attr = BKE_sculpt_attribute_get(ob, domain, proptype, name);
+
+  if (attr) {
+    return attr;
+  }
+
+  attr = sculpt_alloc_attr(ss);
+
+  /* Create attribute. */
+  sculpt_attribute_create(
+      ss, ob, domain, proptype, name, attr, params, pbvhtype, flat_array_for_bmesh);
+  sculpt_attribute_update_refs(ob);
+
+  return attr;
+}
+
+SculptAttribute *BKE_sculpt_attribute_ensure(Object *ob,
+                                             eAttrDomain domain,
+                                             eCustomDataType proptype,
+                                             const char *name,
+                                             const SculptAttributeParams *params)
+{
+  SculptAttributeParams temp_params = *params;
+
+  return sculpt_attribute_ensure_ex(
+      ob, domain, proptype, name, &temp_params, BKE_pbvh_type(ob->sculpt->pbvh), true);
+}
+
+static void sculptsession_bmesh_attr_update_internal(Object *ob)
+{
+  SculptSession *ss = ob->sculpt;
+
+  sculptsession_bmesh_add_layers(ob);
+
+  if (ss->pbvh) {
+    BKE_pbvh_update_bmesh_offsets(ss->pbvh,
+                                  ob->sculpt->attrs.dyntopo_node_id_vertex->bmesh_cd_offset,
+                                  ob->sculpt->attrs.dyntopo_node_id_face->bmesh_cd_offset);
+  }
+}
+
+void sculptsession_bmesh_add_layers(Object *ob)
+{
+  SculptSession *ss = ob->sculpt;
+  SculptAttributeParams params = {0};
+
+  ss->attrs.dyntopo_node_id_vertex = sculpt_attribute_ensure_ex(
+      ob,
+      ATTR_DOMAIN_POINT,
+      CD_PROP_INT32,
+      SCULPT_ATTRIBUTE_NAME(dyntopo_node_id_vertex),
+      ¶ms,
+      PBVH_BMESH,
+      false);
+
+  ss->attrs.dyntopo_node_id_face = sculpt_attribute_ensure_ex(
+      ob,
+      ATTR_DOMAIN_FACE,
+      CD_PROP_INT32,
+      SCULPT_ATTRIBUTE_NAME(dyntopo_node_id_face),
+      ¶ms,
+      PBVH_BMESH,
+      false);
+}
+
+void BKE_sculpt_attributes_destroy_temporary_stroke(Object *ob)
+{
+  SculptSession *ss = ob->sculpt;
+
+  for (int i = 0; i < SCULPT_MAX_ATTRIBUTES; i++) {
+    SculptAttribute *attr = ss->temp_attributes + i;
+
+    if (attr->params.stroke_only) {
+      BKE_sculpt_attribute_destroy(ob, attr);
+    }
+  }
+}
+
+static void sculpt_attribute_update_refs(Object *ob)
+{
+  SculptSession *ss = ob->sculpt;
+
+  /* run twice, in case sculpt_attr_update had to recreate a layer and
+     messed up the bmesh offsets. */
+  for (int i = 0; i < 2; i++) {
+    for (int j = 0; j < SCULPT_MAX_ATTRIBUTES; j++) {
+      SculptAttribute *attr = ss->temp_attributes + j;
+
+      if (attr->used) {
+        sculpt_attr_update(ob, attr);
+      }
+    }
+
+    if (ss->bm) {
+      sculptsession_bmesh_attr_update_internal(ob);
+    }
+  }
+
+  Mesh *me = BKE_object_get_original_mesh(ob);
+
+  if (ss->pbvh) {
+    BKE_pbvh_update_active_vcol(ss->pbvh, me);
+  }
+}
+
+void BKE_sculpt_attribute_destroy_temporary_all(Object *ob)
+{
+  SculptSession *ss = ob->sculpt;
+
+  for (int i = 0; i < SCULPT_MAX_ATTRIBUTES; i++) {
+    SculptAttribute *attr = ss->temp_attributes + i;
+
+    if (attr->used && !attr->params.permanent) {
+      BKE_sculpt_attribute_destroy(ob, attr);
+    }
+  }
+}
+
+bool BKE_sculpt_attribute_destroy(Object *ob, SculptAttribute *attr)
+{
+  SculptSession *ss = ob->sculpt;
+  eAttrDomain domain = attr->domain;
+
+  BLI_assert(attr->used);
+
+  /* Remove from convenience pointer struct. */
+  SculptAttribute **ptrs = (SculptAttribute **)&ss->attrs;
+  int ptrs_num = sizeof(ss->attrs) / sizeof(void *);
+
+  for (int i = 0; i < ptrs_num; i++) {
+    if (ptrs[i] == attr) {
+      ptrs[i] = NULL;
+    }
+  }
+
+  /* Remove from internal temp_attributes array. */
+  for (int i = 0; i < SCULPT_MAX_ATTRIBUTES; i++) {
+    SculptAttribute *attr2 = ss->temp_attributes + i;
+
+    if (STREQ(attr2->name, attr->name) && attr2->domain == attr->domain &&
+        attr2->proptype == attr->proptype) {
+
+      attr2->used = false;
+    }
+  }
+
+  Mesh *me = BKE_object_get_original_mesh(ob);
+
+  if (attr->params.simple_array) {
+    MEM_SAFE_FREE(attr->data);
+  }
+  else if (ss->bm) {
+    CustomData *cdata = attr->domain == ATTR_DOMAIN_POINT ? &ss->bm->vdata : &ss->bm->pdata;
+
+    BM_data_layer_free_named(ss->bm, cdata, attr->name);
+  }
+  else {
+    CustomData *cdata = NULL;
+    int totelem = 0;
+
+    switch (domain) {
+      case ATTR_DOMAIN_POINT:
+        cdata = ss->bm ? &ss->bm->vdata : &me->vdata;
+        totelem = ss->totvert;
+        break;
+      case ATTR_DOMAIN_FACE:
+        cdata = ss->bm ? &ss->bm->pdata : &me->pdata;
+        totelem = ss->totfaces;
+        break;
+      default:
+        BLI_assert_unreachable();
+        return false;
+    }
+
+    /* We may have been called after destroying ss->bm in which case attr->layer
+     * might be invalid.
+     */
+    int layer_i = CustomData_get_named_layer_index(cdata, attr->proptype, attr->name);
+    if (layer_i != 0) {
+      CustomData_free_layer(cdata, attr->proptype, totelem, layer_i);
+    }
+
+    sculpt_attribute_update_refs(ob);
+  }
+
+  attr->data = NULL;
+  attr->used = false;
+
+  return true;
+}
diff --git a/source/blender/blenkernel/intern/particle.c b/source/blender/blenkernel/intern/particle.c
index 2471d3baa59..bbd462d5ae1 100644
--- a/source/blender/blenkernel/intern/particle.c
+++ b/source/blender/blenkernel/intern/particle.c
@@ -53,6 +53,7 @@
 #include "BKE_idtype.h"
 #include "BKE_key.h"
 #include "BKE_lattice.h"
+#include "BKE_layer.h"
 #include "BKE_lib_id.h"
 #include "BKE_lib_query.h"
 #include "BKE_main.h"
@@ -171,7 +172,7 @@ static void particle_settings_foreach_id(ID *id, LibraryForeachIDData *data)
   }
 
   if (psett->effector_weights) {
-    BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, psett->effector_weights->group, IDWALK_CB_NOP);
+    BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, psett->effector_weights->group, IDWALK_CB_USER);
   }
 
   if (psett->pd) {
@@ -494,7 +495,7 @@ IDTypeInfo IDType_ID_PA = {
     .foreach_id = particle_settings_foreach_id,
     .foreach_cache = NULL,
     .foreach_path = NULL,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = particle_settings_blend_write,
     .blend_read_data = particle_settings_blend_read_data,
@@ -761,13 +762,15 @@ static PTCacheEdit *psys_orig_edit_get(ParticleSystem *psys)
 
 bool psys_in_edit_mode(Depsgraph *depsgraph, const ParticleSystem *psys)
 {
-  const ViewLayer *view_layer = DEG_get_input_view_layer(depsgraph);
-  if (view_layer->basact == NULL) {
+  const Scene *scene = DEG_get_input_scene(depsgraph);
+  ViewLayer *view_layer = DEG_get_input_view_layer(depsgraph);
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  const Object *object = BKE_view_layer_active_object_get(view_layer);
+  if (object == NULL) {
     /* TODO(sergey): Needs double-check with multi-object edit. */
     return false;
   }
   const bool use_render_params = (DEG_get_mode(depsgraph) == DAG_EVAL_RENDER);
-  const Object *object = view_layer->basact->object;
   if (object->mode != OB_MODE_PARTICLE_EDIT) {
     return false;
   }
@@ -1399,7 +1402,8 @@ static void init_particle_interpolation(Object *ob,
     pind->dietime = (key + pa->totkey - 1)->time;
 
     if (pind->mesh) {
-      pind->mvert[0] = &pind->mesh->mvert[pa->hair_index];
+      MVert *verts = BKE_mesh_verts_for_write(pind->mesh);
+      pind->mvert[0] = &verts[pa->hair_index];
       pind->mvert[1] = pind->mvert[0] + 1;
     }
   }
@@ -1664,7 +1668,7 @@ static void interpolate_pathcache(ParticleCacheKey *first, float t, ParticleCach
 /************************************************/
 
 void psys_interpolate_face(Mesh *mesh,
-                           MVert *mvert,
+                           const MVert *mvert,
                            const float (*vert_normals)[3],
                            MFace *mface,
                            MTFace *tface,
@@ -1676,7 +1680,7 @@ void psys_interpolate_face(Mesh *mesh,
                            float vtan[3],
                            float orco[3])
 {
-  float *v1 = 0, *v2 = 0, *v3 = 0, *v4 = 0;
+  const float *v1 = 0, *v2 = 0, *v3 = 0, *v4 = 0;
   float e1[3], e2[3], s1, s2, t1, t2;
   float *uv1, *uv2, *uv3, *uv4;
   float n1[3], n2[3], n3[3], n4[3];
@@ -1852,7 +1856,8 @@ static float psys_interpolate_value_from_verts(
       return values[index];
     case PART_FROM_FACE:
     case PART_FROM_VOLUME: {
-      MFace *mf = &mesh->mface[index];
+      MFace *mfaces = CustomData_get_layer(&mesh->fdata, CD_MFACE);
+      MFace *mf = &mfaces[index];
       return interpolate_particle_value(
           values[mf->v1], values[mf->v2], values[mf->v3], values[mf->v4], fw, mf->v4);
     }
@@ -1941,7 +1946,7 @@ int psys_particle_dm_face_lookup(Mesh *mesh_final,
 
   index_mf_to_mpoly_deformed = NULL;
 
-  mtessface_final = mesh_final->mface;
+  mtessface_final = CustomData_get_layer(&mesh_final->fdata, CD_MFACE);
   osface_final = CustomData_get_layer(&mesh_final->fdata, CD_ORIGSPACE);
 
   if (osface_final == NULL) {
@@ -2061,7 +2066,8 @@ static int psys_map_index_on_dm(Mesh *mesh,
       /* modify the original weights to become
        * weights for the derived mesh face */
       OrigSpaceFace *osface = CustomData_get_layer(&mesh->fdata, CD_ORIGSPACE);
-      const MFace *mface = &mesh->mface[i];
+      const MFace *mfaces = CustomData_get_layer(&mesh->fdata, CD_MFACE);
+      const MFace *mface = &mfaces[i];
 
       if (osface == NULL) {
         mapfw[0] = mapfw[1] = mapfw[2] = mapfw[3] = 0.0f;
@@ -2117,7 +2123,8 @@ void psys_particle_on_dm(Mesh *mesh_final,
   const float(*vert_normals)[3] = BKE_mesh_vertex_normals_ensure(mesh_final);
 
   if (from == PART_FROM_VERT) {
-    copy_v3_v3(vec, mesh_final->mvert[mapindex].co);
+    const MVert *verts = BKE_mesh_verts(mesh_final);
+    copy_v3_v3(vec, verts[mapindex].co);
 
     if (nor) {
       copy_v3_v3(nor, vert_normals[mapindex]);
@@ -2143,9 +2150,10 @@ void psys_particle_on_dm(Mesh *mesh_final,
     MTFace *mtface;
     MVert *mvert;
 
-    mface = &mesh_final->mface[mapindex];
-    mvert = mesh_final->mvert;
-    mtface = mesh_final->mtface;
+    MFace *mfaces = CustomData_get_layer(&mesh_final->fdata, CD_MFACE);
+    mface = &mfaces[mapindex];
+    mvert = BKE_mesh_verts_for_write(mesh_final);
+    mtface = CustomData_get_layer(&mesh_final->fdata, CD_MTFACE);
 
     if (mtface) {
       mtface += mapindex;
@@ -2634,7 +2642,7 @@ float *psys_cache_vgroup(Mesh *mesh, ParticleSystem *psys, int vgroup)
     /* hair dynamics pinning vgroup */
   }
   else if (psys->vgroup[vgroup]) {
-    MDeformVert *dvert = mesh->dvert;
+    const MDeformVert *dvert = BKE_mesh_deform_verts(mesh);
     if (dvert) {
       int totvert = mesh->totvert, i;
       vg = MEM_callocN(sizeof(float) * totvert, "vg_cache");
@@ -3494,7 +3502,7 @@ void psys_cache_paths(ParticleSimulationData *sim, float cfra, const bool use_re
      * initial tangent, but taking that in to account will allow
      * the possibility of flipping again. -jahka
      */
-    mat3_to_quat_is_ok(cache[p]->rot, rotmat);
+    mat3_to_quat_legacy(cache[p]->rot, rotmat);
   }
 
   psys->totcached = totpart;
@@ -3684,7 +3692,7 @@ static void psys_cache_edit_paths_iter(void *__restrict iter_data_v,
      * initial tangent, but taking that in to account will allow
      * the possibility of flipping again. -jahka
      */
-    mat3_to_quat_is_ok(cache[iter]->rot, rotmat);
+    mat3_to_quat_legacy(cache[iter]->rot, rotmat);
   }
 }
 
@@ -3848,7 +3856,8 @@ static void psys_face_mat(Object *ob, Mesh *mesh, ParticleData *pa, float mat[4]
     return;
   }
 
-  mface = &mesh->mface[i];
+  MFace *mfaces = CustomData_get_layer(&mesh->fdata, CD_MFACE);
+  mface = &mfaces[i];
   const OrigSpaceFace *osface = CustomData_get(&mesh->fdata, i, CD_ORIGSPACE);
 
   if (orco && (orcodata = CustomData_get_layer(&mesh->vdata, CD_ORCO))) {
@@ -3863,9 +3872,10 @@ static void psys_face_mat(Object *ob, Mesh *mesh, ParticleData *pa, float mat[4]
     }
   }
   else {
-    copy_v3_v3(v[0], mesh->mvert[mface->v1].co);
-    copy_v3_v3(v[1], mesh->mvert[mface->v2].co);
-    copy_v3_v3(v[2], mesh->mvert[mface->v3].co);
+    const MVert *verts = BKE_mesh_verts(mesh);
+    copy_v3_v3(v[0], verts[mface->v1].co);
+    copy_v3_v3(v[1], verts[mface->v2].co);
+    copy_v3_v3(v[2], verts[mface->v3].co);
   }
 
   triatomat(v[0], v[1], v[2], (osface) ? osface->uv : NULL, mat);
@@ -4155,16 +4165,13 @@ static int get_particle_uv(Mesh *mesh,
                            float *texco,
                            bool from_vert)
 {
+  MFace *mfaces = (MFace *)CustomData_get_layer(&mesh->fdata, CD_MFACE);
   MFace *mf;
   const MTFace *tf;
   int i;
 
   tf = CustomData_get_layer_named(&mesh->fdata, CD_MTFACE, name);
 
-  if (tf == NULL) {
-    tf = mesh->mtface;
-  }
-
   if (tf == NULL) {
     return 0;
   }
@@ -4186,7 +4193,7 @@ static int get_particle_uv(Mesh *mesh,
   }
   else {
     if (from_vert) {
-      mf = mesh->mface;
+      mf = mfaces;
 
       /* This finds the first face to contain the emitting vertex,
        * this is not ideal, but is mostly fine as UV seams generally
@@ -4199,7 +4206,7 @@ static int get_particle_uv(Mesh *mesh,
       }
     }
     else {
-      mf = &mesh->mface[i];
+      mf = &mfaces[i];
     }
 
     psys_interpolate_uvs(&tf[i], mf->v4, fuv, texco);
@@ -5413,8 +5420,8 @@ void BKE_particle_system_blend_read_lib(BlendLibReader *reader,
       BLO_read_id_address(reader, id->lib, &psys->target_ob);
 
       if (psys->clmd) {
-        /* XXX(campbell): from reading existing code this seems correct but intended usage of
-         * pointcache /w cloth should be added in 'ParticleSystem'. */
+        /* XXX(@campbellbarton): from reading existing code this seems correct but intended usage
+         * of point-cache with cloth should be added in #ParticleSystem. */
         psys->clmd->point_cache = psys->pointcache;
         psys->clmd->ptcaches.first = psys->clmd->ptcaches.last = NULL;
         BLO_read_id_address(reader, id->lib, &psys->clmd->coll_parms->group);
@@ -5422,7 +5429,7 @@ void BKE_particle_system_blend_read_lib(BlendLibReader *reader,
       }
     }
     else {
-      /* particle modifier must be removed before particle system */
+      /* Particle modifier must be removed before particle system. */
       ParticleSystemModifierData *psmd = psys_get_modifier(ob, psys);
       BKE_modifier_remove_from_list(ob, (ModifierData *)psmd);
       BKE_modifier_free((ModifierData *)psmd);
diff --git a/source/blender/blenkernel/intern/particle_child.c b/source/blender/blenkernel/intern/particle_child.c
index 524ee31229b..a890812cfc4 100644
--- a/source/blender/blenkernel/intern/particle_child.c
+++ b/source/blender/blenkernel/intern/particle_child.c
@@ -158,10 +158,8 @@ static void do_kink_spiral(ParticleThreadContext *ctx,
   int start_index = 0, end_index = 0;
   float kink_base[3];
 
-  if (ptex) {
-    kink_amp *= ptex->kink_amp;
-    kink_freq *= ptex->kink_freq;
-  }
+  kink_amp *= ptex->kink_amp;
+  kink_freq *= ptex->kink_freq;
 
   cut_time = (totkeys - 1) * ptex->length;
   zero_v3(spiral_start);
@@ -405,7 +403,7 @@ void do_kink(ParticleKey *state,
              float obmat[4][4],
              int smooth_start)
 {
-  float kink[3] = {1.0f, 0.0f, 0.0f}, par_vec[3], q1[4] = {1.0f, 0.0f, 0.0f, 0.0f};
+  float kink[3] = {1.0f, 0.0f, 0.0f}, par_vec[3];
   float t, dt = 1.0f, result[3];
 
   if (ELEM(type, PART_KINK_NO, PART_KINK_SPIRAL)) {
@@ -455,6 +453,7 @@ void do_kink(ParticleKey *state,
   switch (type) {
     case PART_KINK_CURL: {
       float curl_offset[3];
+      float q1[4] = {1.0f, 0.0f, 0.0f, 0.0f};
 
       /* rotate kink vector around strand tangent */
       mul_v3_v3fl(curl_offset, kink, amplitude);
diff --git a/source/blender/blenkernel/intern/particle_distribute.c b/source/blender/blenkernel/intern/particle_distribute.c
index da769515f08..561043b553e 100644
--- a/source/blender/blenkernel/intern/particle_distribute.c
+++ b/source/blender/blenkernel/intern/particle_distribute.c
@@ -97,7 +97,7 @@ static void distribute_grid(Mesh *mesh, ParticleSystem *psys)
 {
   ParticleData *pa = NULL;
   float min[3], max[3], delta[3], d;
-  MVert *mv, *mvert = mesh->mvert;
+  MVert *mv, *mvert = BKE_mesh_verts_for_write(mesh);
   int totvert = mesh->totvert, from = psys->part->from;
   int i, j, k, p, res = psys->part->grid_res, size[3], axis;
 
@@ -181,7 +181,7 @@ static void distribute_grid(Mesh *mesh, ParticleSystem *psys)
     int amax = from == PART_FROM_FACE ? 3 : 1;
 
     totface = mesh->totface;
-    mface = mface_array = mesh->mface;
+    mface = mface_array = CustomData_get_layer(&mesh->fdata, CD_MFACE);
 
     for (a = 0; a < amax; a++) {
       if (a == 0) {
@@ -453,7 +453,7 @@ static int distribute_binary_search(const float *sum, int n, float value)
   return low;
 }
 
-/* the max number if calls to rng_* funcs within psys_thread_distribute_particle
+/* the max number if calls to rng_* functions within psys_thread_distribute_particle
  * be sure to keep up to date if this changes */
 #define PSYS_RND_DIST_SKIP 3
 
@@ -464,7 +464,7 @@ static void distribute_from_verts_exec(ParticleTask *thread, ParticleData *pa, i
   ParticleThreadContext *ctx = thread->ctx;
   MFace *mface;
 
-  mface = ctx->mesh->mface;
+  mface = CustomData_get_layer(&ctx->mesh->fdata, CD_MFACE);
 
   int rng_skip_tot = PSYS_RND_DIST_SKIP; /* count how many rng_* calls won't need skipping */
 
@@ -525,10 +525,11 @@ static void distribute_from_faces_exec(ParticleTask *thread, ParticleData *pa, i
   int i;
   int rng_skip_tot = PSYS_RND_DIST_SKIP; /* count how many rng_* calls won't need skipping */
 
+  MFace *mfaces = (MFace *)CustomData_get_layer(&mesh->fdata, CD_MFACE);
   MFace *mface;
 
   pa->num = i = ctx->index[p];
-  mface = &mesh->mface[i];
+  mface = &mfaces[i];
 
   switch (distr) {
     case PART_DISTR_JIT:
@@ -575,10 +576,11 @@ static void distribute_from_volume_exec(ParticleTask *thread, ParticleData *pa,
   int rng_skip_tot = PSYS_RND_DIST_SKIP; /* count how many rng_* calls won't need skipping */
 
   MFace *mface;
-  MVert *mvert = mesh->mvert;
+  MVert *mvert = BKE_mesh_verts_for_write(mesh);
 
   pa->num = i = ctx->index[p];
-  mface = &mesh->mface[i];
+  MFace *mfaces = (MFace *)CustomData_get_layer(&mesh->fdata, CD_MFACE);
+  mface = &mfaces[i];
 
   switch (distr) {
     case PART_DISTR_JIT:
@@ -619,8 +621,8 @@ static void distribute_from_volume_exec(ParticleTask *thread, ParticleData *pa,
 
   min_d = FLT_MAX;
   intersect = 0;
-
-  for (i = 0, mface = mesh->mface; i < tot; i++, mface++) {
+  mface = CustomData_get_layer(&mesh->fdata, CD_MFACE);
+  for (i = 0; i < tot; i++, mface++) {
     if (i == pa->num) {
       continue;
     }
@@ -689,7 +691,8 @@ static void distribute_children_exec(ParticleTask *thread, ChildParticle *cpa, i
     return;
   }
 
-  mf = &mesh->mface[ctx->index[p]];
+  MFace *mfaces = (MFace *)CustomData_get_layer(&mesh->fdata, CD_MFACE);
+  mf = &mfaces[ctx->index[p]];
 
   randu = BLI_rng_get_float(thread->rng);
   randv = BLI_rng_get_float(thread->rng);
@@ -989,7 +992,7 @@ static int psys_thread_context_init_distribute(ParticleThreadContext *ctx,
     BKE_mesh_orco_ensure(ob, mesh);
 
     if (from == PART_FROM_VERT) {
-      MVert *mv = mesh->mvert;
+      MVert *mv = BKE_mesh_verts_for_write(mesh);
       const float(*orcodata)[3] = CustomData_get_layer(&mesh->vdata, CD_ORCO);
       int totvert = mesh->totvert;
 
@@ -1042,8 +1045,9 @@ static int psys_thread_context_init_distribute(ParticleThreadContext *ctx,
 
     orcodata = CustomData_get_layer(&mesh->vdata, CD_ORCO);
 
+    MFace *mfaces = (MFace *)CustomData_get_layer(&mesh->fdata, CD_MFACE);
     for (i = 0; i < totelem; i++) {
-      MFace *mf = &mesh->mface[i];
+      MFace *mf = &mfaces[i];
 
       if (orcodata) {
         /* Transform orcos from normalized 0..1 to object space. */
@@ -1059,14 +1063,15 @@ static int psys_thread_context_init_distribute(ParticleThreadContext *ctx,
         }
       }
       else {
-        v1 = &mesh->mvert[mf->v1];
-        v2 = &mesh->mvert[mf->v2];
-        v3 = &mesh->mvert[mf->v3];
+        MVert *verts = BKE_mesh_verts_for_write(mesh);
+        v1 = &verts[mf->v1];
+        v2 = &verts[mf->v2];
+        v3 = &verts[mf->v3];
         copy_v3_v3(co1, v1->co);
         copy_v3_v3(co2, v2->co);
         copy_v3_v3(co3, v3->co);
         if (mf->v4) {
-          v4 = &mesh->mvert[mf->v4];
+          v4 = &verts[mf->v4];
           copy_v3_v3(co4, v4->co);
         }
       }
@@ -1105,8 +1110,9 @@ static int psys_thread_context_init_distribute(ParticleThreadContext *ctx,
       }
     }
     else { /* PART_FROM_FACE / PART_FROM_VOLUME */
+      MFace *mfaces = (MFace *)CustomData_get_layer(&mesh->fdata, CD_MFACE);
       for (i = 0; i < totelem; i++) {
-        MFace *mf = &mesh->mface[i];
+        MFace *mf = &mfaces[i];
         tweight = vweight[mf->v1] + vweight[mf->v2] + vweight[mf->v3];
 
         if (mf->v4) {
diff --git a/source/blender/blenkernel/intern/particle_system.c b/source/blender/blenkernel/intern/particle_system.c
index 4a8f029beee..9608676a153 100644
--- a/source/blender/blenkernel/intern/particle_system.c
+++ b/source/blender/blenkernel/intern/particle_system.c
@@ -837,7 +837,7 @@ void psys_get_birth_coords(
     cross_v3_v3v3(mat[1], mat[2], mat[0]);
 
     /* apply rotation */
-    mat3_to_quat_is_ok(q, mat);
+    mat3_to_quat_legacy(q, mat);
     copy_qt_qt(state->rot, q);
   }
   else {
@@ -969,7 +969,7 @@ void psys_get_birth_coords(
           float tmat[3][3];
 
           /* NOTE: utan_local is not taken from 'utan', we calculate from rot_vec/vtan. */
-          /* NOTE(campbell): it looks like rotation phase may be applied twice
+          /* NOTE(@campbellbarton): it looks like rotation phase may be applied twice
            * (once with vtan, again below) however this isn't the case. */
           float *rot_vec_local = tmat[0];
           float *vtan_local = tmat[1];
@@ -3322,12 +3322,10 @@ static void hair_create_input_mesh(ParticleSimulationData *sim,
   mesh = *r_mesh;
   if (!mesh) {
     *r_mesh = mesh = BKE_mesh_new_nomain(totpoint, totedge, 0, 0, 0);
-    CustomData_add_layer(&mesh->vdata, CD_MDEFORMVERT, CD_CALLOC, NULL, mesh->totvert);
-    BKE_mesh_update_customdata_pointers(mesh, false);
   }
-  mvert = mesh->mvert;
-  medge = mesh->medge;
-  dvert = mesh->dvert;
+  mvert = BKE_mesh_verts_for_write(mesh);
+  medge = BKE_mesh_edges_for_write(mesh);
+  dvert = BKE_mesh_deform_verts_for_write(mesh);
 
   if (psys->clmd->hairdata == NULL) {
     psys->clmd->hairdata = MEM_mallocN(sizeof(ClothHairData) * totpoint, "hair data");
diff --git a/source/blender/blenkernel/intern/pbvh.c b/source/blender/blenkernel/intern/pbvh.c
index 00a4eee47e3..2bed18de6cf 100644
--- a/source/blender/blenkernel/intern/pbvh.c
+++ b/source/blender/blenkernel/intern/pbvh.c
@@ -145,9 +145,14 @@ static void update_node_vb(PBVH *pbvh, PBVHNode *node)
 //  BB_expand(&node->vb, co);
 //}
 
-static bool face_materials_match(const MPoly *f1, const MPoly *f2)
+static bool face_materials_match(const PBVH *pbvh, const int a, const int b)
 {
-  return ((f1->flag & ME_SMOOTH) == (f2->flag & ME_SMOOTH) && (f1->mat_nr == f2->mat_nr));
+  if (pbvh->material_indices) {
+    if (pbvh->material_indices[a] != pbvh->material_indices[b]) {
+      return false;
+    }
+  }
+  return (pbvh->mpoly[a].flag & ME_SMOOTH) == (pbvh->mpoly[b].flag & ME_SMOOTH);
 }
 
 static bool grid_materials_match(const DMFlagMat *f1, const DMFlagMat *f2)
@@ -180,30 +185,23 @@ static int partition_indices(int *prim_indices, int lo, int hi, int axis, float
 /* Returns the index of the first element on the right of the partition */
 static int partition_indices_material(PBVH *pbvh, int lo, int hi)
 {
-  const MPoly *mpoly = pbvh->mpoly;
   const MLoopTri *looptri = pbvh->looptri;
   const DMFlagMat *flagmats = pbvh->grid_flag_mats;
   const int *indices = pbvh->prim_indices;
-  const void *first;
   int i = lo, j = hi;
 
-  if (pbvh->looptri) {
-    first = &mpoly[looptri[pbvh->prim_indices[lo]].poly];
-  }
-  else {
-    first = &flagmats[pbvh->prim_indices[lo]];
-  }
-
   for (;;) {
     if (pbvh->looptri) {
-      for (; face_materials_match(first, &mpoly[looptri[indices[i]].poly]); i++) {
+      const int first = looptri[pbvh->prim_indices[lo]].poly;
+      for (; face_materials_match(pbvh, first, looptri[indices[i]].poly); i++) {
         /* pass */
       }
-      for (; !face_materials_match(first, &mpoly[looptri[indices[j]].poly]); j--) {
+      for (; !face_materials_match(pbvh, first, looptri[indices[j]].poly); j--) {
         /* pass */
       }
     }
     else {
+      const DMFlagMat *first = &flagmats[pbvh->prim_indices[lo]];
       for (; grid_materials_match(first, &flagmats[indices[i]]); i++) {
         /* pass */
       }
@@ -287,7 +285,7 @@ static void build_mesh_leaf_node(PBVH *pbvh, PBVHNode *node)
     }
 
     if (has_visible == false) {
-      if (!paint_is_face_hidden(lt, pbvh->verts, pbvh->mloop)) {
+      if (!paint_is_face_hidden(lt, pbvh->hide_poly)) {
         has_visible = true;
       }
     }
@@ -368,26 +366,6 @@ int BKE_pbvh_count_grid_quads(BLI_bitmap **grid_hidden,
   return totquad;
 }
 
-void BKE_pbvh_sync_face_sets_to_grids(PBVH *pbvh)
-{
-  const int gridsize = pbvh->gridkey.grid_size;
-  for (int i = 0; i < pbvh->totgrid; i++) {
-    BLI_bitmap *gh = pbvh->grid_hidden[i];
-    const int face_index = BKE_subdiv_ccg_grid_to_face_index(pbvh->subdiv_ccg, i);
-    if (!gh && pbvh->face_sets[face_index] < 0) {
-      gh = pbvh->grid_hidden[i] = BLI_BITMAP_NEW(pbvh->gridkey.grid_area,
-                                                 "partialvis_update_grids");
-    }
-    if (gh) {
-      for (int y = 0; y < gridsize; y++) {
-        for (int x = 0; x < gridsize; x++) {
-          BLI_BITMAP_SET(gh, y * gridsize + x, pbvh->face_sets[face_index] < 0);
-        }
-      }
-    }
-  }
-}
-
 static void build_grid_leaf_node(PBVH *pbvh, PBVHNode *node)
 {
   int totquads = BKE_pbvh_count_grid_quads(
@@ -424,12 +402,9 @@ static bool leaf_needs_material_split(PBVH *pbvh, int offset, int count)
 
   if (pbvh->looptri) {
     const MLoopTri *first = &pbvh->looptri[pbvh->prim_indices[offset]];
-    const MPoly *mp = &pbvh->mpoly[first->poly];
-
     for (int i = offset + count - 1; i > offset; i--) {
       int prim = pbvh->prim_indices[i];
-      const MPoly *mp_other = &pbvh->mpoly[pbvh->looptri[prim].poly];
-      if (!face_materials_match(mp, mp_other)) {
+      if (!face_materials_match(pbvh, first->poly, pbvh->looptri[prim].poly)) {
         return true;
       }
     }
@@ -555,13 +530,17 @@ void BKE_pbvh_build_mesh(PBVH *pbvh,
   BB cb;
 
   pbvh->mesh = mesh;
-  pbvh->type = PBVH_FACES;
+  pbvh->header.type = PBVH_FACES;
   pbvh->mpoly = mpoly;
+  pbvh->hide_poly = (bool *)CustomData_get_layer_named(&mesh->pdata, CD_PROP_BOOL, ".hide_poly");
+  pbvh->material_indices = (const int *)CustomData_get_layer_named(
+      &mesh->pdata, CD_PROP_INT32, "material_index");
   pbvh->mloop = mloop;
   pbvh->looptri = looptri;
   pbvh->verts = verts;
   BKE_mesh_vertex_normals_ensure(mesh);
   pbvh->vert_normals = BKE_mesh_vertex_normals_for_write(mesh);
+  pbvh->hide_vert = (bool *)CustomData_get_layer_named(&mesh->vdata, CD_PROP_BOOL, ".hide_vert");
   pbvh->vert_bitmap = MEM_calloc_arrayN(totvert, sizeof(bool), "bvh->vert_bitmap");
   pbvh->totvert = totvert;
   pbvh->leaf_limit = LEAF_LIMIT;
@@ -615,7 +594,7 @@ void BKE_pbvh_build_grids(PBVH *pbvh,
 {
   const int gridsize = key->grid_size;
 
-  pbvh->type = PBVH_GRIDS;
+  pbvh->header.type = PBVH_GRIDS;
   pbvh->grids = grids;
   pbvh->gridfaces = gridfaces;
   pbvh->grid_flag_mats = flagmats;
@@ -652,11 +631,12 @@ void BKE_pbvh_build_grids(PBVH *pbvh,
   MEM_freeN(prim_bbc);
 }
 
-PBVH *BKE_pbvh_new(void)
+PBVH *BKE_pbvh_new(PBVHType type)
 {
   PBVH *pbvh = MEM_callocN(sizeof(PBVH), "pbvh");
   pbvh->respect_hide = true;
   pbvh->draw_cache_invalid = true;
+  pbvh->header.type = type;
   return pbvh;
 }
 
@@ -1274,7 +1254,7 @@ bool BKE_pbvh_get_color_layer(const Mesh *me, CustomDataLayer **r_layer, eAttrDo
 
   if (!layer || !ELEM(layer->type, CD_PROP_COLOR, CD_PROP_BYTE_COLOR)) {
     *r_layer = NULL;
-    *r_attr = ATTR_DOMAIN_NUM;
+    *r_attr = ATTR_DOMAIN_POINT;
     return false;
   }
 
@@ -1282,7 +1262,7 @@ bool BKE_pbvh_get_color_layer(const Mesh *me, CustomDataLayer **r_layer, eAttrDo
 
   if (!ELEM(domain, ATTR_DOMAIN_POINT, ATTR_DOMAIN_CORNER)) {
     *r_layer = NULL;
-    *r_attr = ATTR_DOMAIN_NUM;
+    *r_attr = ATTR_DOMAIN_POINT;
     return false;
   }
 
@@ -1303,19 +1283,8 @@ static void pbvh_update_draw_buffer_cb(void *__restrict userdata,
   PBVH *pbvh = data->pbvh;
   PBVHNode *node = data->nodes[n];
 
-  CustomData *vdata, *ldata;
-
-  if (!pbvh->bm) {
-    vdata = pbvh->vdata;
-    ldata = pbvh->ldata;
-  }
-  else {
-    vdata = &pbvh->bm->vdata;
-    ldata = &pbvh->bm->ldata;
-  }
-
   if (node->flag & PBVH_RebuildDrawBuffers) {
-    switch (pbvh->type) {
+    switch (pbvh->header.type) {
       case PBVH_GRIDS: {
         bool smooth = node->totprim > 0 ?
                           pbvh->grid_flag_mats[node->prim_indices[0]].flag & ME_SMOOTH :
@@ -1326,14 +1295,7 @@ static void pbvh_update_draw_buffer_cb(void *__restrict userdata,
       }
       case PBVH_FACES:
         node->draw_buffers = GPU_pbvh_mesh_buffers_build(
-            pbvh->mpoly,
-            pbvh->mloop,
-            pbvh->looptri,
-            pbvh->verts,
-            node->prim_indices,
-            CustomData_get_layer(pbvh->pdata, CD_SCULPT_FACE_SETS),
-            node->totprim,
-            pbvh->mesh);
+            pbvh->mesh, pbvh->looptri, node->prim_indices, node->totprim);
         break;
       case PBVH_BMESH:
         node->draw_buffers = GPU_pbvh_bmesh_buffers_build(pbvh->flags &
@@ -1343,8 +1305,10 @@ static void pbvh_update_draw_buffer_cb(void *__restrict userdata,
   }
 
   if (node->flag & PBVH_UpdateDrawBuffers) {
+    node->debug_draw_gen++;
+
     const int update_flags = pbvh_get_buffers_update_flags(pbvh);
-    switch (pbvh->type) {
+    switch (pbvh->header.type) {
       case PBVH_GRIDS:
         GPU_pbvh_grid_buffers_update(pbvh->vbo_id,
                                      node->draw_buffers,
@@ -1360,11 +1324,12 @@ static void pbvh_update_draw_buffer_cb(void *__restrict userdata,
                                      update_flags);
         break;
       case PBVH_FACES: {
+        /* Pass vertices separately because they may be not be the same as the mesh's vertices,
+         * and pass normals separately because they are managed by the PBVH. */
         GPU_pbvh_mesh_buffers_update(pbvh->vbo_id,
                                      node->draw_buffers,
+                                     pbvh->mesh,
                                      pbvh->verts,
-                                     vdata,
-                                     ldata,
                                      CustomData_get_layer(pbvh->vdata, CD_PAINT_MASK),
                                      CustomData_get_layer(pbvh->pdata, CD_SCULPT_FACE_SETS),
                                      pbvh->face_sets_color_seed,
@@ -1376,7 +1341,7 @@ static void pbvh_update_draw_buffer_cb(void *__restrict userdata,
       case PBVH_BMESH:
         GPU_pbvh_bmesh_buffers_update(pbvh->vbo_id,
                                       node->draw_buffers,
-                                      pbvh->bm,
+                                      pbvh->header.bm,
                                       node->bm_faces,
                                       node->bm_unique_verts,
                                       node->bm_other_verts,
@@ -1405,15 +1370,15 @@ static void pbvh_check_draw_layout(PBVH *pbvh)
     pbvh->vbo_id = GPU_pbvh_make_format();
   }
 
-  switch (pbvh->type) {
+  switch (pbvh->header.type) {
     case PBVH_BMESH:
-      if (!pbvh->bm) {
+      if (!pbvh->header.bm) {
         /* BMesh hasn't been created yet */
         return;
       }
 
-      vdata = &pbvh->bm->vdata;
-      ldata = &pbvh->bm->ldata;
+      vdata = &pbvh->header.bm->vdata;
+      ldata = &pbvh->header.bm->ldata;
       break;
     case PBVH_FACES:
       vdata = pbvh->vdata;
@@ -1431,7 +1396,7 @@ static void pbvh_check_draw_layout(PBVH *pbvh)
    * (there's no guarantee there isn't another EEVEE viewport which would
    *  free the draw buffers and corrupt the draw cache).
    */
-  if (GPU_pbvh_attribute_names_update(pbvh->type, pbvh->vbo_id, vdata, ldata, false)) {
+  if (GPU_pbvh_attribute_names_update(pbvh->header.type, pbvh->vbo_id, vdata, ldata, false)) {
     /* attribute layout changed; force rebuild */
     for (int i = 0; i < pbvh->totnode; i++) {
       PBVHNode *node = pbvh->nodes + i;
@@ -1451,14 +1416,14 @@ static void pbvh_update_draw_buffers(PBVH *pbvh, PBVHNode **nodes, int totnode,
     pbvh->vbo_id = GPU_pbvh_make_format();
   }
 
-  switch (pbvh->type) {
+  switch (pbvh->header.type) {
     case PBVH_BMESH:
-      if (!pbvh->bm) {
+      if (!pbvh->header.bm) {
         /* BMesh hasn't been created yet */
         return;
       }
 
-      vdata = &pbvh->bm->vdata;
+      vdata = &pbvh->header.bm->vdata;
       break;
     case PBVH_FACES:
       vdata = pbvh->vdata;
@@ -1469,7 +1434,7 @@ static void pbvh_update_draw_buffers(PBVH *pbvh, PBVHNode **nodes, int totnode,
   }
   UNUSED_VARS(vdata);
 
-  if ((update_flag & PBVH_RebuildDrawBuffers) || ELEM(pbvh->type, PBVH_GRIDS, PBVH_BMESH)) {
+  if ((update_flag & PBVH_RebuildDrawBuffers) || ELEM(pbvh->header.type, PBVH_GRIDS, PBVH_BMESH)) {
     /* Free buffers uses OpenGL, so not in parallel. */
     for (int n = 0; n < totnode; n++) {
       PBVHNode *node = nodes[n];
@@ -1477,11 +1442,11 @@ static void pbvh_update_draw_buffers(PBVH *pbvh, PBVHNode **nodes, int totnode,
         pbvh_free_draw_buffers(pbvh, node);
       }
       else if ((node->flag & PBVH_UpdateDrawBuffers) && node->draw_buffers) {
-        if (pbvh->type == PBVH_GRIDS) {
+        if (pbvh->header.type == PBVH_GRIDS) {
           GPU_pbvh_grid_buffers_update_free(
               node->draw_buffers, pbvh->grid_flag_mats, node->prim_indices);
         }
-        else if (pbvh->type == PBVH_BMESH) {
+        else if (pbvh->header.type == PBVH_BMESH) {
           GPU_pbvh_bmesh_buffers_update_free(node->draw_buffers);
         }
       }
@@ -1602,9 +1567,12 @@ static void pbvh_faces_node_visibility_update(PBVH *pbvh, PBVHNode *node)
   BKE_pbvh_node_num_verts(pbvh, node, NULL, &totvert);
   BKE_pbvh_node_get_verts(pbvh, node, &vert_indices, &mvert);
 
+  if (pbvh->hide_vert == NULL) {
+    BKE_pbvh_node_fully_hidden_set(node, false);
+    return;
+  }
   for (i = 0; i < totvert; i++) {
-    MVert *v = &mvert[vert_indices[i]];
-    if (!(v->flag & ME_HIDE)) {
+    if (!(pbvh->hide_vert[vert_indices[i]])) {
       BKE_pbvh_node_fully_hidden_set(node, false);
       return;
     }
@@ -1795,15 +1763,10 @@ void BKE_pbvh_get_grid_updates(PBVH *pbvh, bool clear, void ***r_gridfaces, int
 
 /***************************** PBVH Access ***********************************/
 
-PBVHType BKE_pbvh_type(const PBVH *pbvh)
-{
-  return pbvh->type;
-}
-
 bool BKE_pbvh_has_faces(const PBVH *pbvh)
 {
-  if (pbvh->type == PBVH_BMESH) {
-    return (pbvh->bm->totface != 0);
+  if (pbvh->header.type == PBVH_BMESH) {
+    return (pbvh->header.bm->totface != 0);
   }
 
   return (pbvh->totprim != 0);
@@ -1824,46 +1787,40 @@ void BKE_pbvh_bounding_box(const PBVH *pbvh, float min[3], float max[3])
 
 BLI_bitmap **BKE_pbvh_grid_hidden(const PBVH *pbvh)
 {
-  BLI_assert(pbvh->type == PBVH_GRIDS);
+  BLI_assert(pbvh->header.type == PBVH_GRIDS);
   return pbvh->grid_hidden;
 }
 
 const CCGKey *BKE_pbvh_get_grid_key(const PBVH *pbvh)
 {
-  BLI_assert(pbvh->type == PBVH_GRIDS);
+  BLI_assert(pbvh->header.type == PBVH_GRIDS);
   return &pbvh->gridkey;
 }
 
 struct CCGElem **BKE_pbvh_get_grids(const PBVH *pbvh)
 {
-  BLI_assert(pbvh->type == PBVH_GRIDS);
+  BLI_assert(pbvh->header.type == PBVH_GRIDS);
   return pbvh->grids;
 }
 
 BLI_bitmap **BKE_pbvh_get_grid_visibility(const PBVH *pbvh)
 {
-  BLI_assert(pbvh->type == PBVH_GRIDS);
+  BLI_assert(pbvh->header.type == PBVH_GRIDS);
   return pbvh->grid_hidden;
 }
 
-int BKE_pbvh_get_grid_num_vertices(const PBVH *pbvh)
+int BKE_pbvh_get_grid_num_verts(const PBVH *pbvh)
 {
-  BLI_assert(pbvh->type == PBVH_GRIDS);
+  BLI_assert(pbvh->header.type == PBVH_GRIDS);
   return pbvh->totgrid * pbvh->gridkey.grid_area;
 }
 
 int BKE_pbvh_get_grid_num_faces(const PBVH *pbvh)
 {
-  BLI_assert(pbvh->type == PBVH_GRIDS);
+  BLI_assert(pbvh->header.type == PBVH_GRIDS);
   return pbvh->totgrid * (pbvh->gridkey.grid_size - 1) * (pbvh->gridkey.grid_size - 1);
 }
 
-BMesh *BKE_pbvh_get_bmesh(PBVH *pbvh)
-{
-  BLI_assert(pbvh->type == PBVH_BMESH);
-  return pbvh->bm;
-}
-
 /***************************** Node Access ***********************************/
 
 void BKE_pbvh_node_mark_update(PBVHNode *node)
@@ -1964,10 +1921,10 @@ bool BKE_pbvh_node_fully_unmasked_get(PBVHNode *node)
   return (node->flag & PBVH_Leaf) && (node->flag & PBVH_FullyUnmasked);
 }
 
-void BKE_pbvh_vert_mark_update(PBVH *pbvh, int index)
+void BKE_pbvh_vert_tag_update_normal(PBVH *pbvh, PBVHVertRef vertex)
 {
-  BLI_assert(pbvh->type == PBVH_FACES);
-  pbvh->vert_bitmap[index] = true;
+  BLI_assert(pbvh->header.type == PBVH_FACES);
+  pbvh->vert_bitmap[vertex.i] = true;
 }
 
 void BKE_pbvh_node_get_loops(PBVH *pbvh,
@@ -2004,7 +1961,7 @@ void BKE_pbvh_node_num_verts(PBVH *pbvh, PBVHNode *node, int *r_uniquevert, int
 {
   int tot;
 
-  switch (pbvh->type) {
+  switch (pbvh->header.type) {
     case PBVH_GRIDS:
       tot = node->totprim * pbvh->gridkey.grid_area;
       if (r_totvert) {
@@ -2042,7 +1999,7 @@ void BKE_pbvh_node_get_grids(PBVH *pbvh,
                              int *r_gridsize,
                              CCGElem ***r_griddata)
 {
-  switch (pbvh->type) {
+  switch (pbvh->header.type) {
     case PBVH_GRIDS:
       if (r_grid_indices) {
         *r_grid_indices = node->prim_indices;
@@ -2123,9 +2080,9 @@ void BKE_pbvh_node_get_bm_orco_data(PBVHNode *node,
   *r_orco_coords = node->bm_orco;
 }
 
-bool BKE_pbvh_node_vert_update_check_any(PBVH *pbvh, PBVHNode *node)
+bool BKE_pbvh_node_has_vert_with_normal_update_tag(PBVH *pbvh, PBVHNode *node)
 {
-  BLI_assert(pbvh->type == PBVH_FACES);
+  BLI_assert(pbvh->header.type == PBVH_FACES);
   const int *verts = node->vert_indices;
   const int totvert = node->uniq_verts + node->face_verts;
 
@@ -2299,7 +2256,7 @@ static bool pbvh_faces_node_raycast(PBVH *pbvh,
                                     const float ray_normal[3],
                                     struct IsectRayPrecalc *isect_precalc,
                                     float *depth,
-                                    int *r_active_vertex_index,
+                                    PBVHVertRef *r_active_vertex,
                                     int *r_active_face_index,
                                     float *r_face_normal)
 {
@@ -2314,7 +2271,7 @@ static bool pbvh_faces_node_raycast(PBVH *pbvh,
     const MLoopTri *lt = &pbvh->looptri[faces[i]];
     const int *face_verts = node->face_vert_indices[i];
 
-    if (pbvh->respect_hide && paint_is_face_hidden(lt, vert, mloop)) {
+    if (pbvh->respect_hide && paint_is_face_hidden(lt, pbvh->hide_poly)) {
       continue;
     }
 
@@ -2339,7 +2296,7 @@ static bool pbvh_faces_node_raycast(PBVH *pbvh,
         normal_tri_v3(r_face_normal, co[0], co[1], co[2]);
       }
 
-      if (r_active_vertex_index) {
+      if (r_active_vertex) {
         float location[3] = {0.0f};
         madd_v3_v3v3fl(location, ray_start, ray_normal, *depth);
         for (int j = 0; j < 3; j++) {
@@ -2349,7 +2306,7 @@ static bool pbvh_faces_node_raycast(PBVH *pbvh,
           if (j == 0 ||
               len_squared_v3v3(location, co[j]) < len_squared_v3v3(location, nearest_vertex_co)) {
             copy_v3_v3(nearest_vertex_co, co[j]);
-            *r_active_vertex_index = mloop[lt->tri[j]].v;
+            r_active_vertex->i = mloop[lt->tri[j]].v;
             *r_active_face_index = lt->poly;
           }
         }
@@ -2367,7 +2324,7 @@ static bool pbvh_grids_node_raycast(PBVH *pbvh,
                                     const float ray_normal[3],
                                     struct IsectRayPrecalc *isect_precalc,
                                     float *depth,
-                                    int *r_active_vertex_index,
+                                    PBVHVertRef *r_active_vertex,
                                     int *r_active_grid_index,
                                     float *r_face_normal)
 {
@@ -2419,12 +2376,12 @@ static bool pbvh_grids_node_raycast(PBVH *pbvh,
             normal_quad_v3(r_face_normal, co[0], co[1], co[2], co[3]);
           }
 
-          if (r_active_vertex_index) {
+          if (r_active_vertex) {
             float location[3] = {0.0};
             madd_v3_v3v3fl(location, ray_start, ray_normal, *depth);
 
             const int x_it[4] = {0, 1, 1, 0};
-            const int y_it[4] = {0, 0, 1, 1};
+            const int y_it[4] = {1, 1, 0, 0};
 
             for (int j = 0; j < 4; j++) {
               /* Always assign nearest_vertex_co in the first iteration to avoid comparison against
@@ -2434,8 +2391,8 @@ static bool pbvh_grids_node_raycast(PBVH *pbvh,
                                 len_squared_v3v3(location, nearest_vertex_co)) {
                 copy_v3_v3(nearest_vertex_co, co[j]);
 
-                *r_active_vertex_index = gridkey->grid_area * grid_index +
-                                         (y + y_it[j]) * gridkey->grid_size + (x + x_it[j]);
+                r_active_vertex->i = gridkey->grid_area * grid_index +
+                                     (y + y_it[j]) * gridkey->grid_size + (x + x_it[j]);
               }
             }
           }
@@ -2462,7 +2419,7 @@ bool BKE_pbvh_node_raycast(PBVH *pbvh,
                            const float ray_normal[3],
                            struct IsectRayPrecalc *isect_precalc,
                            float *depth,
-                           int *active_vertex_index,
+                           PBVHVertRef *active_vertex,
                            int *active_face_grid_index,
                            float *face_normal)
 {
@@ -2472,7 +2429,7 @@ bool BKE_pbvh_node_raycast(PBVH *pbvh,
     return false;
   }
 
-  switch (pbvh->type) {
+  switch (pbvh->header.type) {
     case PBVH_FACES:
       hit |= pbvh_faces_node_raycast(pbvh,
                                      node,
@@ -2481,7 +2438,7 @@ bool BKE_pbvh_node_raycast(PBVH *pbvh,
                                      ray_normal,
                                      isect_precalc,
                                      depth,
-                                     active_vertex_index,
+                                     active_vertex,
                                      active_face_grid_index,
                                      face_normal);
       break;
@@ -2493,19 +2450,19 @@ bool BKE_pbvh_node_raycast(PBVH *pbvh,
                                      ray_normal,
                                      isect_precalc,
                                      depth,
-                                     active_vertex_index,
+                                     active_vertex,
                                      active_face_grid_index,
                                      face_normal);
       break;
     case PBVH_BMESH:
-      BM_mesh_elem_index_ensure(pbvh->bm, BM_VERT);
+      BM_mesh_elem_index_ensure(pbvh->header.bm, BM_VERT);
       hit = pbvh_bmesh_node_raycast(node,
                                     ray_start,
                                     ray_normal,
                                     isect_precalc,
                                     depth,
                                     use_origco,
-                                    active_vertex_index,
+                                    active_vertex,
                                     face_normal);
       break;
   }
@@ -2623,7 +2580,7 @@ static bool pbvh_faces_node_nearest_to_ray(PBVH *pbvh,
     const MLoopTri *lt = &pbvh->looptri[faces[i]];
     const int *face_verts = node->face_vert_indices[i];
 
-    if (pbvh->respect_hide && paint_is_face_hidden(lt, vert, mloop)) {
+    if (pbvh->respect_hide && paint_is_face_hidden(lt, pbvh->hide_poly)) {
       continue;
     }
 
@@ -2729,7 +2686,7 @@ bool BKE_pbvh_node_find_nearest_to_ray(PBVH *pbvh,
     return false;
   }
 
-  switch (pbvh->type) {
+  switch (pbvh->header.type) {
     case PBVH_FACES:
       hit |= pbvh_faces_node_nearest_to_ray(
           pbvh, node, origco, ray_start, ray_normal, depth, dist_sq);
@@ -2820,13 +2777,13 @@ void BKE_pbvh_update_normals(PBVH *pbvh, struct SubdivCCG *subdiv_ccg)
       pbvh, update_search_cb, POINTER_FROM_INT(PBVH_UpdateNormals), &nodes, &totnode);
 
   if (totnode > 0) {
-    if (pbvh->type == PBVH_BMESH) {
+    if (pbvh->header.type == PBVH_BMESH) {
       pbvh_bmesh_normals_update(nodes, totnode);
     }
-    else if (pbvh->type == PBVH_FACES) {
+    else if (pbvh->header.type == PBVH_FACES) {
       pbvh_faces_update_normals(pbvh, nodes, totnode);
     }
-    else if (pbvh->type == PBVH_GRIDS) {
+    else if (pbvh->header.type == PBVH_GRIDS) {
       struct CCGFace **faces;
       int num_faces;
       BKE_pbvh_get_grid_updates(pbvh, true, (void ***)&faces, &num_faces);
@@ -2917,15 +2874,18 @@ void BKE_pbvh_draw_cb(PBVH *pbvh,
   MEM_SAFE_FREE(nodes);
 }
 
-void BKE_pbvh_draw_debug_cb(
-    PBVH *pbvh,
-    void (*draw_fn)(void *user_data, const float bmin[3], const float bmax[3], PBVHNodeFlags flag),
-    void *user_data)
+void BKE_pbvh_draw_debug_cb(PBVH *pbvh,
+                            void (*draw_fn)(PBVHNode *node,
+                                            void *user_data,
+                                            const float bmin[3],
+                                            const float bmax[3],
+                                            PBVHNodeFlags flag),
+                            void *user_data)
 {
   for (int a = 0; a < pbvh->totnode; a++) {
     PBVHNode *node = &pbvh->nodes[a];
 
-    draw_fn(user_data, node->vb.bmin, node->vb.bmax, node->flag);
+    draw_fn(node, user_data, node->vb.bmin, node->vb.bmax, node->flag);
   }
 }
 
@@ -2991,7 +2951,7 @@ void BKE_pbvh_vert_coords_apply(PBVH *pbvh, const float (*vertCos)[3], const int
       /* no need for float comparison here (memory is exactly equal or not) */
       if (memcmp(mvert->co, vertCos[a], sizeof(float[3])) != 0) {
         copy_v3_v3(mvert->co, vertCos[a]);
-        BKE_pbvh_vert_mark_update(pbvh, a);
+        BKE_pbvh_vert_tag_update_normal(pbvh, BKE_pbvh_make_vref(a));
       }
     }
 
@@ -3108,6 +3068,7 @@ void pbvh_vertex_iter_init(PBVH *pbvh, PBVHNode *node, PBVHVertexIter *vi, int m
   vi->no = NULL;
   vi->fno = NULL;
   vi->mvert = NULL;
+  vi->vertex.i = 0LL;
 
   vi->respect_hide = pbvh->respect_hide;
   if (pbvh->respect_hide == false) {
@@ -3134,10 +3095,10 @@ void pbvh_vertex_iter_init(PBVH *pbvh, PBVHNode *node, PBVHVertexIter *vi, int m
   vi->vert_indices = vert_indices;
   vi->mverts = verts;
 
-  if (pbvh->type == PBVH_BMESH) {
+  if (pbvh->header.type == PBVH_BMESH) {
     BLI_gsetIterator_init(&vi->bm_unique_verts, node->bm_unique_verts);
     BLI_gsetIterator_init(&vi->bm_other_verts, node->bm_other_verts);
-    vi->bm_vdata = &pbvh->bm->vdata;
+    vi->bm_vdata = &pbvh->header.bm->vdata;
     vi->cd_vert_mask_offset = CustomData_get_offset(vi->bm_vdata, CD_PAINT_MASK);
   }
 
@@ -3147,8 +3108,9 @@ void pbvh_vertex_iter_init(PBVH *pbvh, PBVHNode *node, PBVHVertexIter *vi, int m
   }
 
   vi->mask = NULL;
-  if (pbvh->type == PBVH_FACES) {
+  if (pbvh->header.type == PBVH_FACES) {
     vi->vert_normals = pbvh->vert_normals;
+    vi->hide_vert = pbvh->hide_vert;
 
     vi->vmask = CustomData_get_layer(pbvh->vdata, CD_PAINT_MASK);
   }
@@ -3156,13 +3118,14 @@ void pbvh_vertex_iter_init(PBVH *pbvh, PBVHNode *node, PBVHVertexIter *vi, int m
 
 bool pbvh_has_mask(const PBVH *pbvh)
 {
-  switch (pbvh->type) {
+  switch (pbvh->header.type) {
     case PBVH_GRIDS:
       return (pbvh->gridkey.has_mask != 0);
     case PBVH_FACES:
       return (pbvh->vdata && CustomData_get_layer(pbvh->vdata, CD_PAINT_MASK));
     case PBVH_BMESH:
-      return (pbvh->bm && (CustomData_get_offset(&pbvh->bm->vdata, CD_PAINT_MASK) != -1));
+      return (pbvh->header.bm &&
+              (CustomData_get_offset(&pbvh->header.bm->vdata, CD_PAINT_MASK) != -1));
   }
 
   return false;
@@ -3170,7 +3133,7 @@ bool pbvh_has_mask(const PBVH *pbvh)
 
 bool pbvh_has_face_sets(PBVH *pbvh)
 {
-  switch (pbvh->type) {
+  switch (pbvh->header.type) {
     case PBVH_GRIDS:
       return (pbvh->pdata && CustomData_get_layer(pbvh->pdata, CD_SCULPT_FACE_SETS));
     case PBVH_FACES:
@@ -3218,16 +3181,43 @@ void BKE_pbvh_parallel_range_settings(TaskParallelSettings *settings,
 
 MVert *BKE_pbvh_get_verts(const PBVH *pbvh)
 {
-  BLI_assert(pbvh->type == PBVH_FACES);
+  BLI_assert(pbvh->header.type == PBVH_FACES);
   return pbvh->verts;
 }
 
 const float (*BKE_pbvh_get_vert_normals(const PBVH *pbvh))[3]
 {
-  BLI_assert(pbvh->type == PBVH_FACES);
+  BLI_assert(pbvh->header.type == PBVH_FACES);
   return pbvh->vert_normals;
 }
 
+const bool *BKE_pbvh_get_vert_hide(const PBVH *pbvh)
+{
+  BLI_assert(pbvh->header.type == PBVH_FACES);
+  return pbvh->hide_vert;
+}
+
+const bool *BKE_pbvh_get_poly_hide(const PBVH *pbvh)
+{
+  BLI_assert(ELEM(pbvh->header.type, PBVH_FACES, PBVH_GRIDS));
+  return pbvh->hide_poly;
+}
+
+bool *BKE_pbvh_get_vert_hide_for_write(PBVH *pbvh)
+{
+  BLI_assert(pbvh->header.type == PBVH_FACES);
+  if (pbvh->hide_vert) {
+    return pbvh->hide_vert;
+  }
+  pbvh->hide_vert = CustomData_get_layer_named(&pbvh->mesh->vdata, CD_PROP_BOOL, ".hide_vert");
+  if (pbvh->hide_vert) {
+    return pbvh->hide_vert;
+  }
+  pbvh->hide_vert = (bool *)CustomData_add_layer_named(
+      &pbvh->mesh->vdata, CD_PROP_BOOL, CD_SET_DEFAULT, NULL, pbvh->mesh->totvert, ".hide_vert");
+  return pbvh->hide_vert;
+}
+
 void BKE_pbvh_subdiv_cgg_set(PBVH *pbvh, SubdivCCG *subdiv_ccg)
 {
   pbvh->subdiv_ccg = subdiv_ccg;
@@ -3238,10 +3228,19 @@ void BKE_pbvh_face_sets_set(PBVH *pbvh, int *face_sets)
   pbvh->face_sets = face_sets;
 }
 
+void BKE_pbvh_update_hide_attributes_from_mesh(PBVH *pbvh)
+{
+  if (pbvh->header.type == PBVH_FACES) {
+    pbvh->hide_vert = CustomData_get_layer_named(&pbvh->mesh->vdata, CD_PROP_BOOL, ".hide_vert");
+    pbvh->hide_poly = CustomData_get_layer_named(&pbvh->mesh->pdata, CD_PROP_BOOL, ".hide_poly");
+  }
+}
+
 void BKE_pbvh_respect_hide_set(PBVH *pbvh, bool respect_hide)
 {
   pbvh->respect_hide = respect_hide;
 }
+
 bool BKE_pbvh_is_drawing(const PBVH *pbvh)
 {
   return pbvh->is_drawing;
@@ -3325,3 +3324,8 @@ void BKE_pbvh_ensure_node_loops(PBVH *pbvh)
 
   MEM_SAFE_FREE(visit);
 }
+
+int BKE_pbvh_debug_draw_gen_get(PBVHNode *node)
+{
+  return node->debug_draw_gen;
+}
diff --git a/source/blender/blenkernel/intern/pbvh.cc b/source/blender/blenkernel/intern/pbvh.cc
index dec93826b9b..70aeb10f087 100644
--- a/source/blender/blenkernel/intern/pbvh.cc
+++ b/source/blender/blenkernel/intern/pbvh.cc
@@ -86,10 +86,12 @@ template<> void from_float(const float src[4], MPropCol &dst)
 }
 
 template
-static void pbvh_vertex_color_get(const PBVH &pbvh, int vertex, float r_color[4])
+static void pbvh_vertex_color_get(const PBVH &pbvh, PBVHVertRef vertex, float r_color[4])
 {
+  int index = vertex.i;
+
   if (pbvh.color_domain == ATTR_DOMAIN_CORNER) {
-    const MeshElemMap &melem = pbvh.pmap[vertex];
+    const MeshElemMap &melem = pbvh.pmap[index];
 
     int count = 0;
     zero_v4(r_color);
@@ -99,7 +101,7 @@ static void pbvh_vertex_color_get(const PBVH &pbvh, int vertex, float r_color[4]
       Span loops{pbvh.mloop + mp.loopstart, mp.totloop};
 
       for (const int i_loop : IndexRange(mp.totloop)) {
-        if (loops[i_loop].v == vertex) {
+        if (loops[i_loop].v == index) {
           float temp[4];
           to_float(colors[i_loop], temp);
 
@@ -114,15 +116,17 @@ static void pbvh_vertex_color_get(const PBVH &pbvh, int vertex, float r_color[4]
     }
   }
   else {
-    to_float(static_cast(pbvh.color_layer->data)[vertex], r_color);
+    to_float(static_cast(pbvh.color_layer->data)[index], r_color);
   }
 }
 
 template
-static void pbvh_vertex_color_set(PBVH &pbvh, int vertex, const float color[4])
+static void pbvh_vertex_color_set(PBVH &pbvh, PBVHVertRef vertex, const float color[4])
 {
+  int index = vertex.i;
+
   if (pbvh.color_domain == ATTR_DOMAIN_CORNER) {
-    const MeshElemMap &melem = pbvh.pmap[vertex];
+    const MeshElemMap &melem = pbvh.pmap[index];
 
     for (const int i_poly : Span(melem.indices, melem.count)) {
       const MPoly &mp = pbvh.mpoly[i_poly];
@@ -130,21 +134,21 @@ static void pbvh_vertex_color_set(PBVH &pbvh, int vertex, const float color[4])
       Span loops{pbvh.mloop + mp.loopstart, mp.totloop};
 
       for (const int i_loop : IndexRange(mp.totloop)) {
-        if (loops[i_loop].v == vertex) {
+        if (loops[i_loop].v == index) {
           from_float(color, colors[i_loop]);
         }
       }
     }
   }
   else {
-    from_float(color, static_cast(pbvh.color_layer->data)[vertex]);
+    from_float(color, static_cast(pbvh.color_layer->data)[index]);
   }
 }
 
 }  // namespace blender::bke
 
 extern "C" {
-void BKE_pbvh_vertex_color_get(const PBVH *pbvh, int vertex, float r_color[4])
+void BKE_pbvh_vertex_color_get(const PBVH *pbvh, PBVHVertRef vertex, float r_color[4])
 {
   blender::bke::to_static_color_type(eCustomDataType(pbvh->color_layer->type), [&](auto dummy) {
     using T = decltype(dummy);
@@ -152,7 +156,7 @@ void BKE_pbvh_vertex_color_get(const PBVH *pbvh, int vertex, float r_color[4])
   });
 }
 
-void BKE_pbvh_vertex_color_set(PBVH *pbvh, int vertex, const float color[4])
+void BKE_pbvh_vertex_color_set(PBVH *pbvh, PBVHVertRef vertex, const float color[4])
 {
   blender::bke::to_static_color_type(eCustomDataType(pbvh->color_layer->type), [&](auto dummy) {
     using T = decltype(dummy);
@@ -202,7 +206,7 @@ void BKE_pbvh_store_colors_vertex(PBVH *pbvh,
     blender::bke::to_static_color_type(eCustomDataType(pbvh->color_layer->type), [&](auto dummy) {
       using T = decltype(dummy);
       for (const int i : IndexRange(indices_num)) {
-        blender::bke::pbvh_vertex_color_get(*pbvh, indices[i], r_colors[i]);
+        blender::bke::pbvh_vertex_color_get(*pbvh, BKE_pbvh_make_vref(indices[i]), r_colors[i]);
       }
     });
   }
diff --git a/source/blender/blenkernel/intern/pbvh_bmesh.c b/source/blender/blenkernel/intern/pbvh_bmesh.c
index 112fd01c699..70d442021fe 100644
--- a/source/blender/blenkernel/intern/pbvh_bmesh.c
+++ b/source/blender/blenkernel/intern/pbvh_bmesh.c
@@ -400,7 +400,7 @@ static bool pbvh_bmesh_node_limit_ensure(PBVH *pbvh, int node_index)
     BM_elem_index_set(f, i); /* set_dirty! */
   }
   /* Likely this is already dirty. */
-  pbvh->bm->elem_index_dirty |= BM_FACE;
+  pbvh->header.bm->elem_index_dirty |= BM_FACE;
 
   pbvh_bmesh_node_split(pbvh, bbc_array, node_index);
 
@@ -484,8 +484,8 @@ static BMVert *pbvh_bmesh_vert_create(PBVH *pbvh,
   BLI_assert((pbvh->totnode == 1 || node_index) && node_index <= pbvh->totnode);
 
   /* avoid initializing customdata because its quite involved */
-  BMVert *v = BM_vert_create(pbvh->bm, co, NULL, BM_CREATE_SKIP_CD);
-  CustomData_bmesh_set_default(&pbvh->bm->vdata, &v->head.data);
+  BMVert *v = BM_vert_create(pbvh->header.bm, co, NULL, BM_CREATE_SKIP_CD);
+  CustomData_bmesh_set_default(&pbvh->header.bm->vdata, &v->head.data);
 
   /* This value is logged below */
   copy_v3_v3(v->no, no);
@@ -512,7 +512,7 @@ static BMFace *pbvh_bmesh_face_create(
   /* ensure we never add existing face */
   BLI_assert(!BM_face_exists(v_tri, 3));
 
-  BMFace *f = BM_face_create(pbvh->bm, v_tri, e_tri, 3, f_example, BM_CREATE_NOP);
+  BMFace *f = BM_face_create(pbvh->header.bm, v_tri, e_tri, 3, f_example, BM_CREATE_NOP);
   f->head.hflag = f_example->head.hflag;
 
   BLI_gset_insert(node->bm_faces, f);
@@ -1185,22 +1185,22 @@ static void pbvh_bmesh_split_edge(EdgeQueueContext *eq_ctx,
     v_tri[0] = v1;
     v_tri[1] = v_new;
     v_tri[2] = v_opp;
-    bm_edges_from_tri(pbvh->bm, v_tri, e_tri);
+    bm_edges_from_tri(pbvh->header.bm, v_tri, e_tri);
     f_new = pbvh_bmesh_face_create(pbvh, ni, v_tri, e_tri, f_adj);
     long_edge_queue_face_add(eq_ctx, f_new);
 
     v_tri[0] = v_new;
     v_tri[1] = v2;
     /* v_tri[2] = v_opp; */ /* unchanged */
-    e_tri[0] = BM_edge_create(pbvh->bm, v_tri[0], v_tri[1], NULL, BM_CREATE_NO_DOUBLE);
+    e_tri[0] = BM_edge_create(pbvh->header.bm, v_tri[0], v_tri[1], NULL, BM_CREATE_NO_DOUBLE);
     e_tri[2] = e_tri[1]; /* switched */
-    e_tri[1] = BM_edge_create(pbvh->bm, v_tri[1], v_tri[2], NULL, BM_CREATE_NO_DOUBLE);
+    e_tri[1] = BM_edge_create(pbvh->header.bm, v_tri[1], v_tri[2], NULL, BM_CREATE_NO_DOUBLE);
     f_new = pbvh_bmesh_face_create(pbvh, ni, v_tri, e_tri, f_adj);
     long_edge_queue_face_add(eq_ctx, f_new);
 
     /* Delete original */
     pbvh_bmesh_face_remove(pbvh, f_adj);
-    BM_face_kill(pbvh->bm, f_adj);
+    BM_face_kill(pbvh->header.bm, f_adj);
 
     /* Ensure new vertex is in the node */
     if (!BLI_gset_haskey(pbvh->nodes[ni].bm_unique_verts, v_new)) {
@@ -1217,7 +1217,7 @@ static void pbvh_bmesh_split_edge(EdgeQueueContext *eq_ctx,
     }
   }
 
-  BM_edge_kill(pbvh->bm, e);
+  BM_edge_kill(pbvh->header.bm, e);
 }
 
 static bool pbvh_bmesh_subdivide_long_edges(EdgeQueueContext *eq_ctx,
@@ -1303,12 +1303,12 @@ static void pbvh_bmesh_collapse_edge(PBVH *pbvh,
     BMFace *f_adj = l_adj->f;
 
     pbvh_bmesh_face_remove(pbvh, f_adj);
-    BM_face_kill(pbvh->bm, f_adj);
+    BM_face_kill(pbvh->header.bm, f_adj);
   }
 
   /* Kill the edge */
   BLI_assert(BM_edge_is_wire(e));
-  BM_edge_kill(pbvh->bm, e);
+  BM_edge_kill(pbvh->header.bm, e);
 
   /* For all remaining faces of v_del, create a new face that is the
    * same except it uses v_conn instead of v_del */
@@ -1355,7 +1355,7 @@ static void pbvh_bmesh_collapse_edge(PBVH *pbvh,
       BMEdge *e_tri[3];
       PBVHNode *n = pbvh_bmesh_node_from_face(pbvh, f);
       int ni = n - pbvh->nodes;
-      bm_edges_from_tri(pbvh->bm, v_tri, e_tri);
+      bm_edges_from_tri(pbvh->header.bm, v_tri, e_tri);
       pbvh_bmesh_face_create(pbvh, ni, v_tri, e_tri, f);
 
       /* Ensure that v_conn is in the new face's node */
@@ -1388,13 +1388,13 @@ static void pbvh_bmesh_collapse_edge(PBVH *pbvh,
 
     /* Remove the face */
     pbvh_bmesh_face_remove(pbvh, f_del);
-    BM_face_kill(pbvh->bm, f_del);
+    BM_face_kill(pbvh->header.bm, f_del);
 
     /* Check if any of the face's edges are now unused by any
      * face, if so delete them */
     for (int j = 0; j < 3; j++) {
       if (BM_edge_is_wire(e_tri[j])) {
-        BM_edge_kill(pbvh->bm, e_tri[j]);
+        BM_edge_kill(pbvh->header.bm, e_tri[j]);
       }
     }
 
@@ -1410,7 +1410,7 @@ static void pbvh_bmesh_collapse_edge(PBVH *pbvh,
           v_conn = NULL;
         }
         BLI_ghash_insert(deleted_verts, v_tri[j], NULL);
-        BM_vert_kill(pbvh->bm, v_tri[j]);
+        BM_vert_kill(pbvh->header.bm, v_tri[j]);
       }
     }
   }
@@ -1437,7 +1437,7 @@ static void pbvh_bmesh_collapse_edge(PBVH *pbvh,
   BM_log_vert_removed(pbvh->bm_log, v_del, eq_ctx->cd_vert_mask_offset);
   /* v_conn == NULL is OK */
   BLI_ghash_insert(deleted_verts, v_del, v_conn);
-  BM_vert_kill(pbvh->bm, v_del);
+  BM_vert_kill(pbvh->header.bm, v_del);
 }
 
 static bool pbvh_bmesh_collapse_short_edges(EdgeQueueContext *eq_ctx,
@@ -1501,7 +1501,7 @@ bool pbvh_bmesh_node_raycast(PBVHNode *node,
                              struct IsectRayPrecalc *isect_precalc,
                              float *depth,
                              bool use_original,
-                             int *r_active_vertex_index,
+                             PBVHVertRef *r_active_vertex,
                              float *r_face_normal)
 {
   bool hit = false;
@@ -1538,14 +1538,14 @@ bool pbvh_bmesh_node_raycast(PBVHNode *node,
             normal_tri_v3(r_face_normal, v_tri[0]->co, v_tri[1]->co, v_tri[2]->co);
           }
 
-          if (r_active_vertex_index) {
+          if (r_active_vertex) {
             float location[3] = {0.0f};
             madd_v3_v3v3fl(location, ray_start, ray_normal, *depth);
             for (int j = 0; j < 3; j++) {
               if (len_squared_v3v3(location, v_tri[j]->co) <
                   len_squared_v3v3(location, nearest_vertex_co)) {
                 copy_v3_v3(nearest_vertex_co, v_tri[j]->co);
-                *r_active_vertex_index = BM_elem_index_get(v_tri[j]);
+                r_active_vertex->i = (intptr_t)v_tri[j];
               }
             }
           }
@@ -1863,6 +1863,12 @@ static void pbvh_bmesh_create_nodes_fast_recursive(
 
 /***************************** Public API *****************************/
 
+void BKE_pbvh_update_bmesh_offsets(PBVH *pbvh, int cd_vert_node_offset, int cd_face_node_offset)
+{
+  pbvh->cd_vert_node_offset = cd_vert_node_offset;
+  pbvh->cd_face_node_offset = cd_face_node_offset;
+}
+
 void BKE_pbvh_build_bmesh(PBVH *pbvh,
                           BMesh *bm,
                           bool smooth_shading,
@@ -1870,18 +1876,18 @@ void BKE_pbvh_build_bmesh(PBVH *pbvh,
                           const int cd_vert_node_offset,
                           const int cd_face_node_offset)
 {
-  pbvh->cd_vert_node_offset = cd_vert_node_offset;
-  pbvh->cd_face_node_offset = cd_face_node_offset;
-  pbvh->bm = bm;
+  pbvh->header.bm = bm;
 
   BKE_pbvh_bmesh_detail_size_set(pbvh, 0.75);
 
-  pbvh->type = PBVH_BMESH;
+  pbvh->header.type = PBVH_BMESH;
   pbvh->bm_log = log;
 
   /* TODO: choose leaf limit better */
   pbvh->leaf_limit = 100;
 
+  BKE_pbvh_update_bmesh_offsets(pbvh, cd_vert_node_offset, cd_face_node_offset);
+
   if (smooth_shading) {
     pbvh->flags |= PBVH_DYNTOPO_SMOOTH_SHADING;
   }
@@ -1951,7 +1957,7 @@ bool BKE_pbvh_bmesh_update_topology(PBVH *pbvh,
   /* 2 is enough for edge faces - manifold edge */
   BLI_buffer_declare_static(BMLoop *, edge_loops, BLI_BUFFER_NOP, 2);
   BLI_buffer_declare_static(BMFace *, deleted_faces, BLI_BUFFER_NOP, 32);
-  const int cd_vert_mask_offset = CustomData_get_offset(&pbvh->bm->vdata, CD_PAINT_MASK);
+  const int cd_vert_mask_offset = CustomData_get_offset(&pbvh->header.bm->vdata, CD_PAINT_MASK);
   const int cd_vert_node_offset = pbvh->cd_vert_node_offset;
   const int cd_face_node_offset = pbvh->cd_face_node_offset;
 
@@ -1967,7 +1973,7 @@ bool BKE_pbvh_bmesh_update_topology(PBVH *pbvh,
     EdgeQueueContext eq_ctx = {
         &q,
         queue_pool,
-        pbvh->bm,
+        pbvh->header.bm,
         cd_vert_mask_offset,
         cd_vert_node_offset,
         cd_face_node_offset,
@@ -1986,7 +1992,7 @@ bool BKE_pbvh_bmesh_update_topology(PBVH *pbvh,
     EdgeQueueContext eq_ctx = {
         &q,
         queue_pool,
-        pbvh->bm,
+        pbvh->header.bm,
         cd_vert_mask_offset,
         cd_vert_node_offset,
         cd_face_node_offset,
@@ -1999,7 +2005,7 @@ bool BKE_pbvh_bmesh_update_topology(PBVH *pbvh,
     BLI_mempool_destroy(queue_pool);
   }
 
-  /* Unmark nodes */
+  /* Unmark nodes. */
   for (int n = 0; n < pbvh->totnode; n++) {
     PBVHNode *node = &pbvh->nodes[n];
 
@@ -2126,13 +2132,13 @@ static void pbvh_bmesh_print(PBVH *pbvh)
 
   BMIter iter;
   BMFace *f;
-  BM_ITER_MESH (f, &iter, pbvh->bm, BM_FACES_OF_MESH) {
+  BM_ITER_MESH (f, &iter, pbvh->header.bm, BM_FACES_OF_MESH) {
     fprintf(stderr, "  %d -> %d\n", BM_elem_index_get(f), pbvh_bmesh_node_index_from_face(pbvh, f));
   }
 
   fprintf(stderr, "bm_vert_to_node:\n");
   BMVert *v;
-  BM_ITER_MESH (v, &iter, pbvh->bm, BM_FACES_OF_MESH) {
+  BM_ITER_MESH (v, &iter, pbvh->header.bm, BM_FACES_OF_MESH) {
     fprintf(stderr, "  %d -> %d\n", BM_elem_index_get(v), pbvh_bmesh_node_index_from_vert(pbvh, v));
   }
 
@@ -2171,21 +2177,21 @@ static void print_flag_factors(int flag)
 static void pbvh_bmesh_verify(PBVH *pbvh)
 {
   /* build list of faces & verts to lookup */
-  GSet *faces_all = BLI_gset_ptr_new_ex(__func__, pbvh->bm->totface);
+  GSet *faces_all = BLI_gset_ptr_new_ex(__func__, pbvh->header.bm->totface);
   BMIter iter;
 
   {
     BMFace *f;
-    BM_ITER_MESH (f, &iter, pbvh->bm, BM_FACES_OF_MESH) {
+    BM_ITER_MESH (f, &iter, pbvh->header.bm, BM_FACES_OF_MESH) {
       BLI_assert(BM_ELEM_CD_GET_INT(f, pbvh->cd_face_node_offset) != DYNTOPO_NODE_NONE);
       BLI_gset_insert(faces_all, f);
     }
   }
 
-  GSet *verts_all = BLI_gset_ptr_new_ex(__func__, pbvh->bm->totvert);
+  GSet *verts_all = BLI_gset_ptr_new_ex(__func__, pbvh->header.bm->totvert);
   {
     BMVert *v;
-    BM_ITER_MESH (v, &iter, pbvh->bm, BM_VERTS_OF_MESH) {
+    BM_ITER_MESH (v, &iter, pbvh->header.bm, BM_VERTS_OF_MESH) {
       if (BM_ELEM_CD_GET_INT(v, pbvh->cd_vert_node_offset) != DYNTOPO_NODE_NONE) {
         BLI_gset_insert(verts_all, v);
       }
@@ -2207,7 +2213,7 @@ static void pbvh_bmesh_verify(PBVH *pbvh)
 
   {
     BMFace *f;
-    BM_ITER_MESH (f, &iter, pbvh->bm, BM_FACES_OF_MESH) {
+    BM_ITER_MESH (f, &iter, pbvh->header.bm, BM_FACES_OF_MESH) {
       BMIter bm_iter;
       BMVert *v;
       PBVHNode *n = pbvh_bmesh_node_lookup(pbvh, f);
@@ -2240,7 +2246,7 @@ static void pbvh_bmesh_verify(PBVH *pbvh)
   /* Check verts */
   {
     BMVert *v;
-    BM_ITER_MESH (v, &iter, pbvh->bm, BM_VERTS_OF_MESH) {
+    BM_ITER_MESH (v, &iter, pbvh->header.bm, BM_VERTS_OF_MESH) {
       /* vertex isn't tracked */
       if (BM_ELEM_CD_GET_INT(v, pbvh->cd_vert_node_offset) == DYNTOPO_NODE_NONE) {
         continue;
@@ -2286,7 +2292,7 @@ static void pbvh_bmesh_verify(PBVH *pbvh)
 #  if 0
   /* check that every vert belongs somewhere */
   /* Slow */
-  BM_ITER_MESH (vi, &iter, pbvh->bm, BM_VERTS_OF_MESH) {
+  BM_ITER_MESH (vi, &iter, pbvh->header.bm, BM_VERTS_OF_MESH) {
     bool has_unique = false;
     for (int i = 0; i < pbvh->totnode; i++) {
       PBVHNode *n = &pbvh->nodes[i];
@@ -2299,7 +2305,7 @@ static void pbvh_bmesh_verify(PBVH *pbvh)
   }
 
   /* If totvert differs from number of verts inside the hash. hash-totvert is checked above. */
-  BLI_assert(vert_count == pbvh->bm->totvert);
+  BLI_assert(vert_count == pbvh->header.bm->totvert);
 #  endif
 
   /* Check that node elements are recorded in the top level */
diff --git a/source/blender/blenkernel/intern/pbvh_intern.h b/source/blender/blenkernel/intern/pbvh_intern.h
index a4ac2744a73..8ab56839f9c 100644
--- a/source/blender/blenkernel/intern/pbvh_intern.h
+++ b/source/blender/blenkernel/intern/pbvh_intern.h
@@ -123,6 +123,11 @@ struct PBVHNode {
   /* Used to store the brush color during a stroke and composite it over the original color */
   PBVHColorBufferNode color_buffer;
   PBVHPixelsNode pixels;
+
+  /* Used to flash colors of updated node bounding boxes in
+   * debug draw mode (when G.debug_value / bpy.app.debug_value is 889).
+   */
+  int debug_draw_gen;
 };
 
 typedef enum { PBVH_DYNTOPO_SMOOTH_SHADING = 1 } PBVHFlags;
@@ -130,7 +135,7 @@ typedef enum { PBVH_DYNTOPO_SMOOTH_SHADING = 1 } PBVHFlags;
 typedef struct PBVHBMeshLog PBVHBMeshLog;
 
 struct PBVH {
-  PBVHType type;
+  struct PBVHPublic header;
   PBVHFlags flags;
 
   PBVHNode *nodes;
@@ -144,12 +149,16 @@ struct PBVH {
   int leaf_limit;
 
   /* Mesh data */
-  const struct Mesh *mesh;
+  struct Mesh *mesh;
 
   /* NOTE: Normals are not `const` because they can be updated for drawing by sculpt code. */
   float (*vert_normals)[3];
+  bool *hide_vert;
   struct MVert *verts;
   const struct MPoly *mpoly;
+  bool *hide_poly;
+  /** Material indices. Only valid for polygon meshes. */
+  const int *material_indices;
   const struct MLoop *mloop;
   const struct MLoopTri *looptri;
   CustomData *vdata;
@@ -183,7 +192,6 @@ struct PBVH {
   bool respect_hide;
 
   /* Dynamic topology */
-  BMesh *bm;
   float bm_max_edge_len;
   float bm_min_edge_len;
   int cd_vert_node_offset;
@@ -265,7 +273,7 @@ bool pbvh_bmesh_node_raycast(PBVHNode *node,
                              struct IsectRayPrecalc *isect_precalc,
                              float *dist,
                              bool use_original,
-                             int *r_active_vertex_index,
+                             PBVHVertRef *r_active_vertex,
                              float *r_face_normal);
 bool pbvh_bmesh_node_nearest_to_ray(PBVHNode *node,
                                     const float ray_start[3],
diff --git a/source/blender/blenkernel/intern/pbvh_pixels.cc b/source/blender/blenkernel/intern/pbvh_pixels.cc
index 49397797c0d..f733f3145ec 100644
--- a/source/blender/blenkernel/intern/pbvh_pixels.cc
+++ b/source/blender/blenkernel/intern/pbvh_pixels.cc
@@ -2,6 +2,7 @@
  * Copyright 2022 Blender Foundation. All rights reserved. */
 
 #include "BKE_customdata.h"
+#include "BKE_mesh.h"
 #include "BKE_mesh_mapping.h"
 #include "BKE_pbvh.h"
 #include "BKE_pbvh_pixels.hh"
@@ -291,7 +292,8 @@ static void update_pixels(PBVH *pbvh, Mesh *mesh, Image *image, ImageUser *image
 
   for (PBVHNode *node : nodes_to_update) {
     NodeData *node_data = static_cast(node->pixels.node_data);
-    init_triangles(pbvh, node, node_data, mesh->mloop);
+    const Span loops = mesh->loops();
+    init_triangles(pbvh, node, node_data, loops.data());
   }
 
   EncodePixelsUserData user_data;
diff --git a/source/blender/blenkernel/intern/pointcache.c b/source/blender/blenkernel/intern/pointcache.c
index 5d8025dce8a..ce04d781980 100644
--- a/source/blender/blenkernel/intern/pointcache.c
+++ b/source/blender/blenkernel/intern/pointcache.c
@@ -1304,7 +1304,7 @@ static int ptcache_frame_from_filename(const char *filename, const char *ext)
 #define MAX_PTCACHE_PATH FILE_MAX
 #define MAX_PTCACHE_FILE (FILE_MAX * 2)
 
-static int ptcache_path(PTCacheID *pid, char *filename)
+static int ptcache_path(PTCacheID *pid, char *dirname)
 {
   const char *blendfile_path = BKE_main_blendfile_path_from_global();
   Library *lib = (pid->owner_id) ? pid->owner_id->lib : NULL;
@@ -1314,13 +1314,13 @@ static int ptcache_path(PTCacheID *pid, char *filename)
   size_t i;
 
   if (pid->cache->flag & PTCACHE_EXTERNAL) {
-    strcpy(filename, pid->cache->path);
+    strcpy(dirname, pid->cache->path);
 
-    if (BLI_path_is_rel(filename)) {
-      BLI_path_abs(filename, blendfilename);
+    if (BLI_path_is_rel(dirname)) {
+      BLI_path_abs(dirname, blendfilename);
     }
 
-    return BLI_path_slash_ensure(filename); /* new strlen() */
+    return BLI_path_slash_ensure(dirname); /* new strlen() */
   }
   if ((blendfile_path[0] != '\0') || lib) {
     char file[MAX_PTCACHE_PATH]; /* we don't want the dir, only the file */
@@ -1334,28 +1334,28 @@ static int ptcache_path(PTCacheID *pid, char *filename)
     }
 
     /* Add blend file name to pointcache dir. */
-    BLI_snprintf(filename, MAX_PTCACHE_PATH, "//" PTCACHE_PATH "%s", file);
+    BLI_snprintf(dirname, MAX_PTCACHE_PATH, "//" PTCACHE_PATH "%s", file);
 
-    BLI_path_abs(filename, blendfilename);
-    return BLI_path_slash_ensure(filename); /* new strlen() */
+    BLI_path_abs(dirname, blendfilename);
+    return BLI_path_slash_ensure(dirname); /* new strlen() */
   }
 
   /* use the temp path. this is weak but better than not using point cache at all */
   /* temporary directory is assumed to exist and ALWAYS has a trailing slash */
-  BLI_snprintf(filename, MAX_PTCACHE_PATH, "%s" PTCACHE_PATH, BKE_tempdir_session());
+  BLI_snprintf(dirname, MAX_PTCACHE_PATH, "%s" PTCACHE_PATH, BKE_tempdir_session());
 
-  return BLI_path_slash_ensure(filename); /* new strlen() */
+  return BLI_path_slash_ensure(dirname); /* new strlen() */
 }
 
-static size_t ptcache_filename_ext_append(PTCacheID *pid,
-                                          char *filename,
-                                          const size_t filename_len,
+static size_t ptcache_filepath_ext_append(PTCacheID *pid,
+                                          char *filepath,
+                                          const size_t filepath_len,
                                           const bool use_frame_number,
                                           const int cfra)
 {
-  size_t len = filename_len;
+  size_t len = filepath_len;
   char *filename_ext;
-  filename_ext = filename + filename_len;
+  filename_ext = filepath + filepath_len;
   *filename_ext = '\0';
 
   /* PointCaches are inserted in object's list on demand, we need a valid index now. */
@@ -1399,14 +1399,14 @@ static size_t ptcache_filename_ext_append(PTCacheID *pid,
   return len;
 }
 
-static int ptcache_filename(
-    PTCacheID *pid, char *filename, int cfra, const bool do_path, const bool do_ext)
+static int ptcache_filepath(
+    PTCacheID *pid, char *filepath, int cfra, const bool do_path, const bool do_ext)
 {
   int len = 0;
   char *idname;
   char *newname;
-  filename[0] = '\0';
-  newname = filename;
+  filepath[0] = '\0';
+  newname = filepath;
 
   if ((pid->cache->flag & PTCACHE_EXTERNAL) == 0) {
     const char *blendfile_path = BKE_main_blendfile_path_from_global();
@@ -1417,7 +1417,7 @@ static int ptcache_filename(
 
   /* start with temp dir */
   if (do_path) {
-    len = ptcache_path(pid, filename);
+    len = ptcache_path(pid, filepath);
     newname += len;
   }
   if (pid->cache->name[0] == '\0' && (pid->cache->flag & PTCACHE_EXTERNAL) == 0) {
@@ -1437,7 +1437,7 @@ static int ptcache_filename(
   }
 
   if (do_ext) {
-    len += ptcache_filename_ext_append(pid, filename, (size_t)len, true, cfra);
+    len += ptcache_filepath_ext_append(pid, filepath, (size_t)len, true, cfra);
   }
 
   return len; /* make sure the above string is always 16 chars */
@@ -1465,7 +1465,7 @@ static PTCacheFile *ptcache_file_open(PTCacheID *pid, int mode, int cfra)
     }
   }
 
-  ptcache_filename(pid, filepath, cfra, true, true);
+  ptcache_filepath(pid, filepath, cfra, true, true);
 
   if (mode == PTCACHE_FILE_READ) {
     fp = BLI_fopen(filepath, "rb");
@@ -2596,7 +2596,7 @@ void BKE_ptcache_id_clear(PTCacheID *pid, int mode, unsigned int cfra)
   DIR *dir;
   struct dirent *de;
   char path[MAX_PTCACHE_PATH];
-  char filename[MAX_PTCACHE_FILE];
+  char filepath[MAX_PTCACHE_FILE];
   char path_full[MAX_PTCACHE_FILE];
   char ext[MAX_PTCACHE_PATH];
 
@@ -2631,20 +2631,20 @@ void BKE_ptcache_id_clear(PTCacheID *pid, int mode, unsigned int cfra)
           return;
         }
 
-        len = ptcache_filename(pid, filename, cfra, false, false); /* no path */
+        len = ptcache_filepath(pid, filepath, cfra, false, false); /* no path */
         /* append underscore terminator to ensure we don't match similar names
          * from objects whose names start with the same prefix
          */
-        if (len < sizeof(filename) - 2) {
-          BLI_strncpy(filename + len, "_", sizeof(filename) - 2 - len);
+        if (len < sizeof(filepath) - 2) {
+          BLI_strncpy(filepath + len, "_", sizeof(filepath) - 2 - len);
           len += 1;
         }
 
-        ptcache_filename_ext_append(pid, ext, 0, false, 0);
+        ptcache_filepath_ext_append(pid, ext, 0, false, 0);
 
         while ((de = readdir(dir)) != NULL) {
           if (strstr(de->d_name, ext)) {               /* Do we have the right extension? */
-            if (STREQLEN(filename, de->d_name, len)) { /* Do we have the right prefix. */
+            if (STREQLEN(filepath, de->d_name, len)) { /* Do we have the right prefix. */
               if (mode == PTCACHE_CLEAR_ALL) {
                 pid->cache->last_exact = MIN2(pid->cache->startframe, 0);
                 BLI_join_dirfile(path_full, sizeof(path_full), path, de->d_name);
@@ -2713,8 +2713,8 @@ void BKE_ptcache_id_clear(PTCacheID *pid, int mode, unsigned int cfra)
     case PTCACHE_CLEAR_FRAME:
       if (pid->cache->flag & PTCACHE_DISK_CACHE) {
         if (BKE_ptcache_id_exist(pid, cfra)) {
-          ptcache_filename(pid, filename, cfra, true, true); /* no path */
-          BLI_delete(filename, false, false);
+          ptcache_filepath(pid, filepath, cfra, true, true); /* no path */
+          BLI_delete(filepath, false, false);
         }
       }
       else {
@@ -2752,11 +2752,11 @@ bool BKE_ptcache_id_exist(PTCacheID *pid, int cfra)
   }
 
   if (pid->cache->flag & PTCACHE_DISK_CACHE) {
-    char filename[MAX_PTCACHE_FILE];
+    char filepath[MAX_PTCACHE_FILE];
 
-    ptcache_filename(pid, filename, cfra, true, true);
+    ptcache_filepath(pid, filepath, cfra, true, true);
 
-    return BLI_exists(filename);
+    return BLI_exists(filepath);
   }
 
   PTCacheMem *pm = pid->cache->mem_cache.first;
@@ -2824,24 +2824,24 @@ void BKE_ptcache_id_time(
       DIR *dir;
       struct dirent *de;
       char path[MAX_PTCACHE_PATH];
-      char filename[MAX_PTCACHE_FILE];
+      char filepath[MAX_PTCACHE_FILE];
       char ext[MAX_PTCACHE_PATH];
       unsigned int len; /* store the length of the string */
 
       ptcache_path(pid, path);
 
-      len = ptcache_filename(pid, filename, (int)cfra, 0, 0); /* no path */
+      len = ptcache_filepath(pid, filepath, (int)cfra, 0, 0); /* no path */
 
       dir = opendir(path);
       if (dir == NULL) {
         return;
       }
 
-      ptcache_filename_ext_append(pid, ext, 0, false, 0);
+      ptcache_filepath_ext_append(pid, ext, 0, false, 0);
 
       while ((de = readdir(dir)) != NULL) {
         if (strstr(de->d_name, ext)) {               /* Do we have the right extension? */
-          if (STREQLEN(filename, de->d_name, len)) { /* Do we have the right prefix. */
+          if (STREQLEN(filepath, de->d_name, len)) { /* Do we have the right prefix. */
             /* read the number of the file */
             const int frame = ptcache_frame_from_filename(de->d_name, ext);
 
@@ -3494,7 +3494,7 @@ void BKE_ptcache_disk_cache_rename(PTCacheID *pid, const char *name_src, const c
   DIR *dir;
   struct dirent *de;
   char path[MAX_PTCACHE_PATH];
-  char old_filename[MAX_PTCACHE_FILE];
+  char old_filepath[MAX_PTCACHE_FILE];
   char new_path_full[MAX_PTCACHE_FILE];
   char old_path_full[MAX_PTCACHE_FILE];
   char ext[MAX_PTCACHE_PATH];
@@ -3510,7 +3510,7 @@ void BKE_ptcache_disk_cache_rename(PTCacheID *pid, const char *name_src, const c
   /* get "from" filename */
   BLI_strncpy(pid->cache->name, name_src, sizeof(pid->cache->name));
 
-  len = ptcache_filename(pid, old_filename, 0, false, false); /* no path */
+  len = ptcache_filepath(pid, old_filepath, 0, false, false); /* no path */
 
   ptcache_path(pid, path);
   dir = opendir(path);
@@ -3519,20 +3519,20 @@ void BKE_ptcache_disk_cache_rename(PTCacheID *pid, const char *name_src, const c
     return;
   }
 
-  ptcache_filename_ext_append(pid, ext, 0, false, 0);
+  ptcache_filepath_ext_append(pid, ext, 0, false, 0);
 
   /* put new name into cache */
   BLI_strncpy(pid->cache->name, name_dst, sizeof(pid->cache->name));
 
   while ((de = readdir(dir)) != NULL) {
     if (strstr(de->d_name, ext)) {                   /* Do we have the right extension? */
-      if (STREQLEN(old_filename, de->d_name, len)) { /* Do we have the right prefix. */
+      if (STREQLEN(old_filepath, de->d_name, len)) { /* Do we have the right prefix. */
         /* read the number of the file */
         const int frame = ptcache_frame_from_filename(de->d_name, ext);
 
         if (frame != -1) {
           BLI_join_dirfile(old_path_full, sizeof(old_path_full), path, de->d_name);
-          ptcache_filename(pid, new_path_full, frame, true, true);
+          ptcache_filepath(pid, new_path_full, frame, true, true);
           BLI_rename(old_path_full, new_path_full);
         }
       }
@@ -3556,7 +3556,7 @@ void BKE_ptcache_load_external(PTCacheID *pid)
   DIR *dir;
   struct dirent *de;
   char path[MAX_PTCACHE_PATH];
-  char filename[MAX_PTCACHE_FILE];
+  char filepath[MAX_PTCACHE_FILE];
   char ext[MAX_PTCACHE_PATH];
 
   if (!cache) {
@@ -3565,7 +3565,7 @@ void BKE_ptcache_load_external(PTCacheID *pid)
 
   ptcache_path(pid, path);
 
-  len = ptcache_filename(pid, filename, 1, false, false); /* no path */
+  len = ptcache_filepath(pid, filepath, 1, false, false); /* no path */
 
   dir = opendir(path);
   if (dir == NULL) {
@@ -3583,7 +3583,7 @@ void BKE_ptcache_load_external(PTCacheID *pid)
 
   while ((de = readdir(dir)) != NULL) {
     if (strstr(de->d_name, ext)) {               /* Do we have the right extension? */
-      if (STREQLEN(filename, de->d_name, len)) { /* Do we have the right prefix. */
+      if (STREQLEN(filepath, de->d_name, len)) { /* Do we have the right prefix. */
         /* read the number of the file */
         const int frame = ptcache_frame_from_filename(de->d_name, ext);
 
diff --git a/source/blender/blenkernel/intern/pointcloud.cc b/source/blender/blenkernel/intern/pointcloud.cc
index e38c20d8eb7..5c935bf6daf 100644
--- a/source/blender/blenkernel/intern/pointcloud.cc
+++ b/source/blender/blenkernel/intern/pointcloud.cc
@@ -64,11 +64,10 @@ static void pointcloud_init_data(ID *id)
   CustomData_reset(&pointcloud->pdata);
   CustomData_add_layer_named(&pointcloud->pdata,
                              CD_PROP_FLOAT3,
-                             CD_CALLOC,
+                             CD_SET_DEFAULT,
                              nullptr,
                              pointcloud->totpoint,
                              POINTCLOUD_ATTR_POSITION);
-  BKE_pointcloud_update_customdata_pointers(pointcloud);
 }
 
 static void pointcloud_copy_data(Main *UNUSED(bmain), ID *id_dst, const ID *id_src, const int flag)
@@ -83,7 +82,6 @@ static void pointcloud_copy_data(Main *UNUSED(bmain), ID *id_dst, const ID *id_s
                   CD_MASK_ALL,
                   alloc_type,
                   pointcloud_dst->totpoint);
-  BKE_pointcloud_update_customdata_pointers(pointcloud_dst);
 
   pointcloud_dst->batch_cache = nullptr;
 }
@@ -138,7 +136,6 @@ static void pointcloud_blend_read_data(BlendDataReader *reader, ID *id)
 
   /* Geometry */
   CustomData_blend_read(reader, &pointcloud->pdata, pointcloud->totpoint);
-  BKE_pointcloud_update_customdata_pointers(pointcloud);
 
   /* Materials */
   BLO_read_pointer_array(reader, (void **)&pointcloud->mat);
@@ -178,7 +175,7 @@ IDTypeInfo IDType_ID_PT = {
     /* foreach_id */ pointcloud_foreach_id,
     /* foreach_cache */ nullptr,
     /* foreach_path */ nullptr,
-    /* owner_get */ nullptr,
+    /* owner_pointer_get */ nullptr,
 
     /* blend_write */ pointcloud_blend_write,
     /* blend_read_data */ pointcloud_blend_read_data,
@@ -192,19 +189,30 @@ IDTypeInfo IDType_ID_PT = {
 
 static void pointcloud_random(PointCloud *pointcloud)
 {
+  BLI_assert(pointcloud->totpoint == 0);
   pointcloud->totpoint = 400;
-  CustomData_realloc(&pointcloud->pdata, pointcloud->totpoint);
-  BKE_pointcloud_update_customdata_pointers(pointcloud);
+  CustomData_realloc(&pointcloud->pdata, 0, pointcloud->totpoint);
 
   RNG *rng = BLI_rng_new(0);
 
-  for (int i = 0; i < pointcloud->totpoint; i++) {
-    pointcloud->co[i][0] = 2.0f * BLI_rng_get_float(rng) - 1.0f;
-    pointcloud->co[i][1] = 2.0f * BLI_rng_get_float(rng) - 1.0f;
-    pointcloud->co[i][2] = 2.0f * BLI_rng_get_float(rng) - 1.0f;
-    pointcloud->radius[i] = 0.05f * BLI_rng_get_float(rng);
+  blender::bke::MutableAttributeAccessor attributes = pointcloud->attributes_for_write();
+  blender::bke::SpanAttributeWriter positions =
+      attributes.lookup_or_add_for_write_only_span(POINTCLOUD_ATTR_POSITION,
+                                                           ATTR_DOMAIN_POINT);
+  blender::bke::SpanAttributeWriter radii =
+      attributes.lookup_or_add_for_write_only_span(POINTCLOUD_ATTR_RADIUS,
+                                                          ATTR_DOMAIN_POINT);
+
+  for (const int i : positions.span.index_range()) {
+    positions.span[i] =
+        float3(BLI_rng_get_float(rng), BLI_rng_get_float(rng), BLI_rng_get_float(rng)) * 2.0f -
+        1.0f;
+    radii.span[i] = 0.05f * BLI_rng_get_float(rng);
   }
 
+  positions.finish();
+  radii.finish();
+
   BLI_rng_free(rng);
 }
 
@@ -220,13 +228,6 @@ void *BKE_pointcloud_add_default(Main *bmain, const char *name)
   PointCloud *pointcloud = static_cast(BKE_libblock_alloc(bmain, ID_PT, name, 0));
 
   pointcloud_init_data(&pointcloud->id);
-
-  CustomData_add_layer_named(&pointcloud->pdata,
-                             CD_PROP_FLOAT,
-                             CD_CALLOC,
-                             nullptr,
-                             pointcloud->totpoint,
-                             POINTCLOUD_ATTR_RADIUS);
   pointcloud_random(pointcloud);
 
   return pointcloud;
@@ -238,30 +239,61 @@ PointCloud *BKE_pointcloud_new_nomain(const int totpoint)
       nullptr, ID_PT, BKE_idtype_idcode_to_name(ID_PT), LIB_ID_CREATE_LOCALIZE));
 
   pointcloud_init_data(&pointcloud->id);
-
-  pointcloud->totpoint = totpoint;
-
   CustomData_add_layer_named(&pointcloud->pdata,
                              CD_PROP_FLOAT,
-                             CD_CALLOC,
+                             CD_SET_DEFAULT,
                              nullptr,
                              pointcloud->totpoint,
                              POINTCLOUD_ATTR_RADIUS);
 
+  CustomData_realloc(&pointcloud->pdata, 0, totpoint);
   pointcloud->totpoint = totpoint;
-  CustomData_realloc(&pointcloud->pdata, pointcloud->totpoint);
-  BKE_pointcloud_update_customdata_pointers(pointcloud);
 
   return pointcloud;
 }
 
+void BKE_pointcloud_nomain_to_pointcloud(PointCloud *pointcloud_src,
+                                         PointCloud *pointcloud_dst,
+                                         bool take_ownership)
+{
+  BLI_assert(pointcloud_src->id.tag & LIB_TAG_NO_MAIN);
+
+  eCDAllocType alloctype = CD_DUPLICATE;
+
+  if (take_ownership) {
+    bool has_any_referenced_layers = CustomData_has_referenced(&pointcloud_src->pdata);
+
+    if (!has_any_referenced_layers) {
+      alloctype = CD_ASSIGN;
+    }
+  }
+
+  CustomData_free(&pointcloud_dst->pdata, pointcloud_dst->totpoint);
+
+  const int totpoint = pointcloud_dst->totpoint = pointcloud_src->totpoint;
+  CustomData_copy(
+      &pointcloud_src->pdata, &pointcloud_dst->pdata, CD_MASK_ALL, alloctype, totpoint);
+
+  if (take_ownership) {
+    if (alloctype == CD_ASSIGN) {
+      /* Free the CustomData but keep the layers. */
+      CustomData_free_typemask(&pointcloud_src->pdata, pointcloud_src->totpoint, 0);
+    }
+    BKE_id_free(nullptr, pointcloud_src);
+  }
+}
+
 static std::optional> point_cloud_bounds(
     const PointCloud &pointcloud)
 {
-  Span positions{reinterpret_cast(pointcloud.co), pointcloud.totpoint};
-  if (pointcloud.radius) {
-    Span radii{pointcloud.radius, pointcloud.totpoint};
-    return blender::bounds::min_max_with_radii(positions, radii);
+  blender::bke::AttributeAccessor attributes = pointcloud.attributes();
+  blender::VArraySpan positions = attributes.lookup_or_default(
+      POINTCLOUD_ATTR_POSITION, ATTR_DOMAIN_POINT, float3(0));
+  blender::VArray radii = attributes.lookup_or_default(
+      POINTCLOUD_ATTR_RADIUS, ATTR_DOMAIN_POINT, 0.0f);
+
+  if (!(radii.is_single() && radii.get_internal_single() == 0.0f)) {
+    return blender::bounds::min_max_with_radii(positions, radii.get_internal_span());
   }
   return blender::bounds::min_max(positions);
 }
@@ -307,38 +339,13 @@ BoundBox *BKE_pointcloud_boundbox_get(Object *ob)
   return ob->runtime.bb;
 }
 
-void BKE_pointcloud_update_customdata_pointers(PointCloud *pointcloud)
-{
-  pointcloud->co = static_cast(
-      CustomData_get_layer_named(&pointcloud->pdata, CD_PROP_FLOAT3, POINTCLOUD_ATTR_POSITION));
-  pointcloud->radius = static_cast(
-      CustomData_get_layer_named(&pointcloud->pdata, CD_PROP_FLOAT, POINTCLOUD_ATTR_RADIUS));
-}
-
-bool BKE_pointcloud_customdata_required(const PointCloud *UNUSED(pointcloud), const char *name)
+bool BKE_pointcloud_attribute_required(const PointCloud *UNUSED(pointcloud), const char *name)
 {
   return STREQ(name, POINTCLOUD_ATTR_POSITION);
 }
 
 /* Dependency Graph */
 
-PointCloud *BKE_pointcloud_new_for_eval(const PointCloud *pointcloud_src, int totpoint)
-{
-  PointCloud *pointcloud_dst = static_cast(BKE_id_new_nomain(ID_PT, nullptr));
-  CustomData_free(&pointcloud_dst->pdata, pointcloud_dst->totpoint);
-
-  STRNCPY(pointcloud_dst->id.name, pointcloud_src->id.name);
-  pointcloud_dst->mat = static_cast(MEM_dupallocN(pointcloud_src->mat));
-  pointcloud_dst->totcol = pointcloud_src->totcol;
-
-  pointcloud_dst->totpoint = totpoint;
-  CustomData_copy(
-      &pointcloud_src->pdata, &pointcloud_dst->pdata, CD_MASK_ALL, CD_CALLOC, totpoint);
-  BKE_pointcloud_update_customdata_pointers(pointcloud_dst);
-
-  return pointcloud_dst;
-}
-
 PointCloud *BKE_pointcloud_copy_for_eval(struct PointCloud *pointcloud_src, bool reference)
 {
   int flags = LIB_ID_COPY_LOCALIZE;
@@ -362,6 +369,8 @@ static void pointcloud_evaluate_modifiers(struct Depsgraph *depsgraph,
   ModifierApplyFlag apply_flag = use_render ? MOD_APPLY_RENDER : MOD_APPLY_USECACHE;
   const ModifierEvalContext mectx = {depsgraph, object, apply_flag};
 
+  BKE_modifiers_clear_errors(object);
+
   /* Get effective list of modifiers to execute. Some effects like shape keys
    * are added as virtual modifiers before the user created modifiers. */
   VirtualModifierData virtualModifierData;
diff --git a/source/blender/blenkernel/intern/report.c b/source/blender/blenkernel/intern/report.c
index 6d654730bca..ccec9c346a8 100644
--- a/source/blender/blenkernel/intern/report.c
+++ b/source/blender/blenkernel/intern/report.c
@@ -258,10 +258,20 @@ char *BKE_reports_string(ReportList *reports, eReportType level)
 
 bool BKE_reports_print_test(const ReportList *reports, eReportType type)
 {
+  if (reports == NULL) {
+    return true;
+  }
+  if (reports->flag & RPT_PRINT_HANDLED_BY_OWNER) {
+    return false;
+  }
   /* In background mode always print otherwise there are cases the errors won't be displayed,
-   * but still add to the report list since this is used for python exception handling. */
-  return (G.background || (reports == NULL) ||
-          ((reports->flag & RPT_PRINT) && (type >= reports->printlevel)));
+   * but still add to the report list since this is used for Python exception handling. */
+  if (G.background) {
+    return true;
+  }
+
+  /* Common case. */
+  return (reports->flag & RPT_PRINT) && (type >= reports->printlevel);
 }
 
 void BKE_reports_print(ReportList *reports, eReportType level)
diff --git a/source/blender/blenkernel/intern/rigidbody.c b/source/blender/blenkernel/intern/rigidbody.c
index 821976f8e0e..2705241425b 100644
--- a/source/blender/blenkernel/intern/rigidbody.c
+++ b/source/blender/blenkernel/intern/rigidbody.c
@@ -364,7 +364,7 @@ static rbCollisionShape *rigidbody_get_shape_convexhull_from_mesh(Object *ob,
 
   if (ob->type == OB_MESH && ob->data) {
     mesh = rigidbody_get_mesh(ob);
-    mvert = (mesh) ? mesh->mvert : NULL;
+    mvert = (mesh) ? BKE_mesh_verts_for_write(mesh) : NULL;
     totvert = (mesh) ? mesh->totvert : 0;
   }
   else {
@@ -390,11 +390,9 @@ static rbCollisionShape *rigidbody_get_shape_trimesh_from_mesh(Object *ob)
 
   if (ob->type == OB_MESH) {
     Mesh *mesh = NULL;
-    MVert *mvert;
     const MLoopTri *looptri;
     int totvert;
     int tottri;
-    const MLoop *mloop;
 
     mesh = rigidbody_get_mesh(ob);
 
@@ -403,11 +401,11 @@ static rbCollisionShape *rigidbody_get_shape_trimesh_from_mesh(Object *ob)
       return NULL;
     }
 
-    mvert = mesh->mvert;
+    const MVert *mvert = BKE_mesh_verts(mesh);
     totvert = mesh->totvert;
     looptri = BKE_mesh_runtime_looptri_ensure(mesh);
     tottri = mesh->runtime.looptris.len;
-    mloop = mesh->mloop;
+    const MLoop *mloop = BKE_mesh_loops(mesh);
 
     /* sanity checking - potential case when no data will be present */
     if ((totvert == 0) || (tottri == 0)) {
@@ -670,21 +668,19 @@ void BKE_rigidbody_calc_volume(Object *ob, float *r_vol)
     case RB_SHAPE_TRIMESH: {
       if (ob->type == OB_MESH) {
         Mesh *mesh = rigidbody_get_mesh(ob);
-        MVert *mvert;
         const MLoopTri *lt = NULL;
         int totvert, tottri = 0;
-        const MLoop *mloop = NULL;
 
         /* ensure mesh validity, then grab data */
         if (mesh == NULL) {
           return;
         }
 
-        mvert = mesh->mvert;
+        const MVert *mvert = BKE_mesh_verts(mesh);
         totvert = mesh->totvert;
         lt = BKE_mesh_runtime_looptri_ensure(mesh);
         tottri = mesh->runtime.looptris.len;
-        mloop = mesh->mloop;
+        const MLoop *mloop = BKE_mesh_loops(mesh);
 
         if (totvert > 0 && tottri > 0) {
           BKE_mesh_calc_volume(mvert, totvert, lt, tottri, mloop, &volume, NULL);
@@ -746,21 +742,19 @@ void BKE_rigidbody_calc_center_of_mass(Object *ob, float r_center[3])
     case RB_SHAPE_TRIMESH: {
       if (ob->type == OB_MESH) {
         Mesh *mesh = rigidbody_get_mesh(ob);
-        MVert *mvert;
         const MLoopTri *looptri;
         int totvert, tottri;
-        const MLoop *mloop;
 
         /* ensure mesh validity, then grab data */
         if (mesh == NULL) {
           return;
         }
 
-        mvert = mesh->mvert;
+        const MVert *mvert = BKE_mesh_verts(mesh);
         totvert = mesh->totvert;
         looptri = BKE_mesh_runtime_looptri_ensure(mesh);
         tottri = mesh->runtime.looptris.len;
-        mloop = mesh->mloop;
+        const MLoop *mloop = BKE_mesh_loops(mesh);
 
         if (totvert > 0 && tottri > 0) {
           BKE_mesh_calc_volume(mvert, totvert, looptri, tottri, mloop, NULL, r_center);
@@ -1176,6 +1170,9 @@ RigidBodyWorld *BKE_rigidbody_world_copy(RigidBodyWorld *rbw, const int flag)
 
   if (rbw->effector_weights) {
     rbw_copy->effector_weights = MEM_dupallocN(rbw->effector_weights);
+    if ((flag & LIB_ID_CREATE_NO_USER_REFCOUNT) == 0) {
+      id_us_plus((ID *)rbw->effector_weights->group);
+    }
   }
   if ((flag & LIB_ID_CREATE_NO_USER_REFCOUNT) == 0) {
     id_us_plus((ID *)rbw_copy->group);
@@ -1205,9 +1202,9 @@ void BKE_rigidbody_world_groups_relink(RigidBodyWorld *rbw)
 
 void BKE_rigidbody_world_id_loop(RigidBodyWorld *rbw, RigidbodyWorldIDFunc func, void *userdata)
 {
-  func(rbw, (ID **)&rbw->group, userdata, IDWALK_CB_NOP);
-  func(rbw, (ID **)&rbw->constraints, userdata, IDWALK_CB_NOP);
-  func(rbw, (ID **)&rbw->effector_weights->group, userdata, IDWALK_CB_NOP);
+  func(rbw, (ID **)&rbw->group, userdata, IDWALK_CB_USER);
+  func(rbw, (ID **)&rbw->constraints, userdata, IDWALK_CB_USER);
+  func(rbw, (ID **)&rbw->effector_weights->group, userdata, IDWALK_CB_USER);
 
   if (rbw->objects) {
     int i;
@@ -1424,7 +1421,7 @@ static bool rigidbody_add_object_to_scene(Main *bmain, Scene *scene, Object *ob)
 
   if (rbw->group == NULL) {
     rbw->group = BKE_collection_add(bmain, NULL, "RigidBodyWorld");
-    id_fake_user_set(&rbw->group->id);
+    id_us_plus(&rbw->group->id);
   }
 
   /* Add object to rigid body group. */
@@ -1453,7 +1450,7 @@ static bool rigidbody_add_constraint_to_scene(Main *bmain, Scene *scene, Object
 
   if (rbw->constraints == NULL) {
     rbw->constraints = BKE_collection_add(bmain, NULL, "RigidBodyConstraints");
-    id_fake_user_set(&rbw->constraints->id);
+    id_us_plus(&rbw->constraints->id);
   }
 
   /* Add object to rigid body group. */
@@ -1548,7 +1545,7 @@ void BKE_rigidbody_remove_object(Main *bmain, Scene *scene, Object *ob, const bo
       FOREACH_COLLECTION_OBJECT_RECURSIVE_END;
     }
 
-    /* Relying on usercount of the object should be OK, and it is much cheaper than looping in all
+    /* Relying on user-count of the object should be OK, and it is much cheaper than looping in all
      * collections to check whether the object is already in another one... */
     if (ID_REAL_USERS(&ob->id) == 1) {
       /* Some users seems to find it funny to use a view-layer instancing collection
@@ -1667,14 +1664,16 @@ static void rigidbody_update_sim_ob(Depsgraph *depsgraph, Object *ob, RigidBodyO
     return;
   }
 
+  const Scene *scene = DEG_get_input_scene(depsgraph);
   ViewLayer *view_layer = DEG_get_input_view_layer(depsgraph);
+  BKE_view_layer_synced_ensure(scene, view_layer);
   Base *base = BKE_view_layer_base_find(view_layer, ob);
   const bool is_selected = base ? (base->flag & BASE_SELECTED) != 0 : false;
 
   if (rbo->shape == RB_SHAPE_TRIMESH && rbo->flag & RBO_FLAG_USE_DEFORM) {
     Mesh *mesh = ob->runtime.mesh_deform_eval;
     if (mesh) {
-      MVert *mvert = mesh->mvert;
+      MVert *mvert = BKE_mesh_verts_for_write(mesh);
       int totvert = mesh->totvert;
       const BoundBox *bb = BKE_object_boundbox_get(ob);
 
@@ -2011,7 +2010,9 @@ static void rigidbody_free_substep_data(ListBase *substep_targets)
 }
 static void rigidbody_update_simulation_post_step(Depsgraph *depsgraph, RigidBodyWorld *rbw)
 {
+  const Scene *scene = DEG_get_input_scene(depsgraph);
   ViewLayer *view_layer = DEG_get_input_view_layer(depsgraph);
+  BKE_view_layer_synced_ensure(scene, view_layer);
 
   FOREACH_COLLECTION_OBJECT_RECURSIVE_BEGIN (rbw->group, ob) {
     Base *base = BKE_view_layer_base_find(view_layer, ob);
diff --git a/source/blender/blenkernel/intern/scene.cc b/source/blender/blenkernel/intern/scene.cc
index 39157bc9890..9c0e5a5534e 100644
--- a/source/blender/blenkernel/intern/scene.cc
+++ b/source/blender/blenkernel/intern/scene.cc
@@ -216,7 +216,7 @@ static void scene_init_data(ID *id)
   }
 
   /* Master Collection */
-  scene->master_collection = BKE_collection_master_add();
+  scene->master_collection = BKE_collection_master_add(scene);
 
   BKE_view_layer_add(scene, "ViewLayer", nullptr, VIEWLAYER_ADD_NEW);
 }
@@ -235,7 +235,7 @@ static void scene_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const int
 {
   Scene *scene_dst = (Scene *)id_dst;
   const Scene *scene_src = (const Scene *)id_src;
-  /* We never handle usercount here for own data. */
+  /* We never handle user-count here for own data. */
   const int flag_subdata = flag | LIB_ID_CREATE_NO_USER_REFCOUNT;
   /* We always need allocation of our private ID data. */
   const int flag_private_id_data = flag & ~LIB_ID_CREATE_NO_ALLOCATE;
@@ -250,6 +250,7 @@ static void scene_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const int
                    (ID *)scene_src->master_collection,
                    (ID **)&scene_dst->master_collection,
                    flag_private_id_data);
+    scene_dst->master_collection->owner_id = &scene_dst->id;
   }
 
   /* View Layers */
@@ -275,6 +276,7 @@ static void scene_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const int
                            (void *)(&scene_src->id),
                            &scene_dst->id,
                            ID_REMAP_SKIP_NEVER_NULL_USAGE | ID_REMAP_SKIP_USER_CLEAR);
+    scene_dst->nodetree->owner_id = &scene_dst->id;
   }
 
   if (scene_src->rigidbody_world) {
@@ -801,8 +803,8 @@ static void scene_foreach_id(ID *id, LibraryForeachIDData *data)
 
   LISTBASE_FOREACH (ViewLayer *, view_layer, &scene->view_layers) {
     BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, view_layer->mat_override, IDWALK_CB_USER);
-
-    LISTBASE_FOREACH (Base *, base, &view_layer->object_bases) {
+    BKE_view_layer_synced_ensure(scene, view_layer);
+    LISTBASE_FOREACH (Base *, base, BKE_view_layer_object_bases_get(view_layer)) {
       BKE_LIB_FOREACHID_PROCESS_IDSUPER(
           data, base->object, IDWALK_CB_NOP | IDWALK_CB_OVERRIDE_LIBRARY_NOT_OVERRIDABLE);
     }
@@ -1054,7 +1056,7 @@ static void scene_blend_write(BlendWriter *writer, ID *id, const void *id_addres
   BKE_curvemapping_curves_blend_write(writer, &sce->r.mblur_shutter_curve);
 
   LISTBASE_FOREACH (ViewLayer *, view_layer, &sce->view_layers) {
-    BKE_view_layer_blend_write(writer, view_layer);
+    BKE_view_layer_blend_write(writer, sce, view_layer);
   }
 
   if (sce->master_collection) {
@@ -1481,7 +1483,7 @@ static void scene_blend_read_lib(BlendLibReader *reader, ID *id)
   }
 
   LISTBASE_FOREACH (TimeMarker *, marker, &sce->markers) {
-    IDP_BlendReadLib(reader, marker->prop);
+    IDP_BlendReadLib(reader, sce->id.lib, marker->prop);
 
     if (marker->camera) {
       BLO_read_id_address(reader, sce->id.lib, &marker->camera);
@@ -1673,7 +1675,7 @@ constexpr IDTypeInfo get_type_info()
   info.foreach_id = scene_foreach_id;
   info.foreach_cache = scene_foreach_cache;
   info.foreach_path = scene_foreach_path;
-  info.owner_get = nullptr;
+  info.owner_pointer_get = nullptr;
 
   info.blend_write = scene_blend_write;
   info.blend_read_data = scene_blend_read_data;
@@ -2048,7 +2050,8 @@ Scene *BKE_scene_add(Main *bmain, const char *name)
 bool BKE_scene_object_find(Scene *scene, Object *ob)
 {
   LISTBASE_FOREACH (ViewLayer *, view_layer, &scene->view_layers) {
-    if (BLI_findptr(&view_layer->object_bases, ob, offsetof(Base, object))) {
+    BKE_view_layer_synced_ensure(scene, view_layer);
+    if (BLI_findptr(BKE_view_layer_object_bases_get(view_layer), ob, offsetof(Base, object))) {
       return true;
     }
   }
@@ -2058,7 +2061,8 @@ bool BKE_scene_object_find(Scene *scene, Object *ob)
 Object *BKE_scene_object_find_by_name(const Scene *scene, const char *name)
 {
   LISTBASE_FOREACH (ViewLayer *, view_layer, &scene->view_layers) {
-    LISTBASE_FOREACH (Base *, base, &view_layer->object_bases) {
+    BKE_view_layer_synced_ensure(scene, view_layer);
+    LISTBASE_FOREACH (Base *, base, BKE_view_layer_object_bases_get(view_layer)) {
       if (STREQ(base->object->id.name + 2, name)) {
         return base->object;
       }
@@ -2079,7 +2083,8 @@ void BKE_scene_set_background(Main *bmain, Scene *scene)
 
   /* copy layers and flags from bases to objects */
   LISTBASE_FOREACH (ViewLayer *, view_layer, &scene->view_layers) {
-    LISTBASE_FOREACH (Base *, base, &view_layer->object_bases) {
+    BKE_view_layer_synced_ensure(scene, view_layer);
+    LISTBASE_FOREACH (Base *, base, BKE_view_layer_object_bases_get(view_layer)) {
       /* collection patch... */
       BKE_scene_object_base_flag_sync_from_base(base);
     }
@@ -2122,7 +2127,8 @@ int BKE_scene_base_iter_next(
       if (iter->phase == F_START) {
         ViewLayer *view_layer = (depsgraph) ? DEG_get_evaluated_view_layer(depsgraph) :
                                               BKE_view_layer_context_active_PLACEHOLDER(*scene);
-        *base = static_cast(view_layer->object_bases.first);
+        BKE_view_layer_synced_ensure(*scene, view_layer);
+        *base = static_cast(BKE_view_layer_object_bases_get(view_layer)->first);
         if (*base) {
           *ob = (*base)->object;
           iter->phase = F_SCENE;
@@ -2132,8 +2138,10 @@ int BKE_scene_base_iter_next(
           while ((*scene)->set) {
             (*scene) = (*scene)->set;
             ViewLayer *view_layer_set = BKE_view_layer_default_render(*scene);
-            if (view_layer_set->object_bases.first) {
-              *base = static_cast(view_layer_set->object_bases.first);
+            BKE_view_layer_synced_ensure(*scene, view_layer_set);
+            ListBase *object_bases = BKE_view_layer_object_bases_get(view_layer_set);
+            if (object_bases->first) {
+              *base = static_cast(object_bases->first);
               *ob = (*base)->object;
               iter->phase = F_SCENE;
               break;
@@ -2153,8 +2161,10 @@ int BKE_scene_base_iter_next(
               while ((*scene)->set) {
                 (*scene) = (*scene)->set;
                 ViewLayer *view_layer_set = BKE_view_layer_default_render(*scene);
-                if (view_layer_set->object_bases.first) {
-                  *base = static_cast(view_layer_set->object_bases.first);
+                BKE_view_layer_synced_ensure(*scene, view_layer_set);
+                ListBase *object_bases = BKE_view_layer_object_bases_get(view_layer_set);
+                if (object_bases->first) {
+                  *base = static_cast(object_bases->first);
                   *ob = (*base)->object;
                   break;
                 }
@@ -2501,9 +2511,11 @@ static bool check_rendered_viewport_visible(Main *bmain)
   return false;
 }
 
-/* TODO(campbell): shouldn't we be able to use 'DEG_get_view_layer' here?
+/* TODO(@campbellbarton): shouldn't we be able to use 'DEG_get_view_layer' here?
  * Currently this is nullptr on load, so don't. */
-static void prepare_mesh_for_viewport_render(Main *bmain, const ViewLayer *view_layer)
+static void prepare_mesh_for_viewport_render(Main *bmain,
+                                             const Scene *scene,
+                                             ViewLayer *view_layer)
 {
   /* This is needed to prepare mesh to be used by the render
    * engine from the viewport rendering. We do loading here
@@ -2513,8 +2525,8 @@ static void prepare_mesh_for_viewport_render(Main *bmain, const ViewLayer *view_
    * This makes it so viewport render engine doesn't need to
    * call loading of the edit data for the mesh objects.
    */
-
-  Object *obedit = OBEDIT_FROM_VIEW_LAYER(view_layer);
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obedit = BKE_view_layer_edit_object_get(view_layer);
   if (obedit) {
     Mesh *mesh = static_cast(obedit->data);
     if ((obedit->type == OB_MESH) &&
@@ -2590,8 +2602,8 @@ static void scene_graph_update_tagged(Depsgraph *depsgraph, Main *bmain, bool on
     /* Uncomment this to check if graph was properly tagged for update. */
     // DEG_debug_graph_relations_validate(depsgraph, bmain, scene);
     /* Flush editing data if needed. */
-    prepare_mesh_for_viewport_render(bmain, view_layer);
-    /* Update all objects: drivers, matrices, #DispList, etc. flags set
+    prepare_mesh_for_viewport_render(bmain, scene, view_layer);
+    /* Update all objects: drivers, matrices, etc. flags set
      * by depsgraph or manual, no layer check here, gets correct flushed. */
     DEG_evaluate_on_refresh(depsgraph);
     /* Update sound system. */
@@ -2666,7 +2678,7 @@ void BKE_scene_graph_update_for_newframe_ex(Depsgraph *depsgraph, const bool cle
     BKE_image_editors_update_frame(bmain, scene->r.cfra);
     BKE_sound_set_cfra(scene->r.cfra);
     DEG_graph_relations_update(depsgraph);
-    /* Update all objects: drivers, matrices, #DispList, etc. flags set
+    /* Update all objects: drivers, matrices, etc. flags set
      * by depsgraph or manual, no layer check here, gets correct flushed.
      *
      * NOTE: Only update for new frame on first iteration. Second iteration is for ensuring user
@@ -2808,8 +2820,10 @@ Base *_setlooper_base_step(Scene **sce_iter, ViewLayer *view_layer, Base *base)
   if ((base == nullptr) && (view_layer != nullptr)) {
     /* First time looping, return the scenes first base. */
     /* For the first loop we should get the layer from workspace when available. */
-    if (view_layer->object_bases.first) {
-      return (Base *)view_layer->object_bases.first;
+    BKE_view_layer_synced_ensure(*sce_iter, view_layer);
+    ListBase *object_bases = BKE_view_layer_object_bases_get(view_layer);
+    if (object_bases->first) {
+      return static_cast(object_bases->first);
     }
     /* No base on this scene layer. */
     goto next_set;
@@ -2819,7 +2833,7 @@ Base *_setlooper_base_step(Scene **sce_iter, ViewLayer *view_layer, Base *base)
     /* Reached the end, get the next base in the set. */
     while ((*sce_iter = (*sce_iter)->set)) {
       ViewLayer *view_layer_set = BKE_view_layer_default_render(*sce_iter);
-      base = (Base *)view_layer_set->object_bases.first;
+      base = (Base *)BKE_view_layer_object_bases_get(view_layer_set)->first;
 
       if (base) {
         return base;
@@ -2878,13 +2892,11 @@ bool BKE_scene_uses_cycles_experimental_features(Scene *scene)
   return RNA_enum_get(&cycles_ptr, "feature_set") == CYCLES_FEATURES_EXPERIMENTAL;
 }
 
-void BKE_scene_base_flag_to_objects(ViewLayer *view_layer)
+void BKE_scene_base_flag_to_objects(const Scene *scene, ViewLayer *view_layer)
 {
-  Base *base = static_cast(view_layer->object_bases.first);
-
-  while (base) {
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  LISTBASE_FOREACH (Base *, base, BKE_view_layer_object_bases_get(view_layer)) {
     BKE_scene_object_base_flag_sync_from_base(base);
-    base = base->next;
   }
 }
 
@@ -2952,6 +2964,20 @@ int BKE_scene_num_threads(const Scene *scene)
   return BKE_render_num_threads(&scene->r);
 }
 
+void BKE_render_resolution(const struct RenderData *r,
+                           const bool use_crop,
+                           int *r_width,
+                           int *r_height)
+{
+  *r_width = (r->xsch * r->size) / 100;
+  *r_height = (r->ysch * r->size) / 100;
+
+  if (use_crop && (r->mode & R_BORDER) && (r->mode & R_CROP)) {
+    *r_width *= BLI_rctf_size_x(&r->border);
+    *r_height *= BLI_rctf_size_y(&r->border);
+  }
+}
+
 int BKE_render_preview_pixel_size(const RenderData *r)
 {
   if (r->preview_pixel_size == 0) {
diff --git a/source/blender/blenkernel/intern/screen.c b/source/blender/blenkernel/intern/screen.c
index 12dc1b6d1fa..03f0c3ff1e9 100644
--- a/source/blender/blenkernel/intern/screen.c
+++ b/source/blender/blenkernel/intern/screen.c
@@ -148,7 +148,6 @@ void BKE_screen_foreach_id_screen_area(LibraryForeachIDData *data, ScrArea *area
       }
       case SPACE_OUTLINER: {
         SpaceOutliner *space_outliner = (SpaceOutliner *)sl;
-        BKE_LIB_FOREACHID_PROCESS_ID(data, space_outliner->search_tse.id, IDWALK_CB_NOP);
         if (space_outliner->treestore != NULL) {
           TreeStoreElem *tselem;
           BLI_mempool_iter iter;
@@ -277,7 +276,7 @@ static void screen_blend_read_lib(BlendLibReader *reader, ID *id)
 
 IDTypeInfo IDType_ID_SCR = {
     .id_code = ID_SCR,
-    .id_filter = 0,
+    .id_filter = FILTER_ID_SCR,
     .main_listbase_index = INDEX_ID_SCR,
     .struct_size = sizeof(bScreen),
     .name = "Screen",
@@ -293,7 +292,7 @@ IDTypeInfo IDType_ID_SCR = {
     .foreach_id = screen_foreach_id,
     .foreach_cache = NULL,
     .foreach_path = NULL,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = screen_blend_write,
     /* Cannot be used yet, because #direct_link_screen has a return value. */
@@ -306,7 +305,7 @@ IDTypeInfo IDType_ID_SCR = {
     .lib_override_apply_post = NULL,
 };
 
-/* ************ Spacetype/regiontype handling ************** */
+/* ************ Space-type/region-type handling ************** */
 
 /* keep global; this has to be accessible outside of windowmanager */
 static ListBase spacetypes = {NULL, NULL};
@@ -1124,40 +1123,50 @@ static void write_uilist(BlendWriter *writer, uiList *ui_list)
   }
 }
 
-static void write_space_outliner(BlendWriter *writer, SpaceOutliner *space_outliner)
+static void write_space_outliner(BlendWriter *writer, const SpaceOutliner *space_outliner)
 {
   BLI_mempool *ts = space_outliner->treestore;
 
   if (ts) {
-    SpaceOutliner space_outliner_flat = *space_outliner;
-
-    int elems = BLI_mempool_len(ts);
+    const int elems = BLI_mempool_len(ts);
     /* linearize mempool to array */
     TreeStoreElem *data = elems ? BLI_mempool_as_arrayN(ts, "TreeStoreElem") : NULL;
 
     if (data) {
-      /* In this block we use the memory location of the treestore
-       * but _not_ its data, the addresses in this case are UUID's,
-       * since we can't rely on malloc giving us different values each time.
+      BLO_write_struct(writer, SpaceOutliner, space_outliner);
+
+      /* To store #TreeStore (instead of the mempool), two unique memory addresses are needed,
+       * which can be used to identify the data on read:
+       * 1) One for the #TreeStore data itself.
+       * 2) One for the array of #TreeStoreElem's inside #TreeStore (#TreeStore.data).
+       *
+       * For 1) we just use the mempool's address (#SpaceOutliner::treestore).
+       * For 2) we don't have such a direct choice. We can't just use the array's address from
+       * above, since that may not be unique over all Outliners. So instead use an address relative
+       * to 1).
        */
-      TreeStore ts_flat = {0};
+      /* TODO the mempool could be moved to #SpaceOutliner_Runtime so that #SpaceOutliner could
+       * hold the #TreeStore directly. */
 
-      /* we know the treestore is at least as big as a pointer,
-       * so offsetting works to give us a UUID. */
+      /* Address relative to the tree-store, as noted above.  */
       void *data_addr = (void *)POINTER_OFFSET(ts, sizeof(void *));
+      /* There should be plenty of memory addresses within the mempool data that we can point into,
+       * just double-check we don't potentially end up with a memory address that another DNA
+       * struct might use. Assumes BLI_mempool uses the guarded allocator. */
+      BLI_assert(MEM_allocN_len(ts) >= sizeof(void *) * 2);
 
+      TreeStore ts_flat = {0};
       ts_flat.usedelem = elems;
       ts_flat.totelem = elems;
       ts_flat.data = data_addr;
 
-      BLO_write_struct(writer, SpaceOutliner, space_outliner);
-
       BLO_write_struct_at_address(writer, TreeStore, ts, &ts_flat);
       BLO_write_struct_array_at_address(writer, TreeStoreElem, elems, data_addr, data);
 
       MEM_freeN(data);
     }
     else {
+      SpaceOutliner space_outliner_flat = *space_outliner;
       space_outliner_flat.treestore = NULL;
       BLO_write_struct_at_address(writer, SpaceOutliner, space_outliner, &space_outliner_flat);
     }
@@ -1653,7 +1662,7 @@ static void direct_link_area(BlendDataReader *reader, ScrArea *area)
       LISTBASE_FOREACH_MUTABLE (ConsoleLine *, cl, &sconsole->history) {
         BLO_read_data_address(reader, &cl->line);
         if (cl->line) {
-          /* the allocted length is not written, so reset here */
+          /* The allocated length is not written, so reset here. */
           cl->len_alloc = cl->len + 1;
         }
         else {
@@ -1873,7 +1882,6 @@ void BKE_screen_area_blend_read_lib(BlendLibReader *reader, ID *parent_id, ScrAr
       }
       case SPACE_OUTLINER: {
         SpaceOutliner *space_outliner = (SpaceOutliner *)sl;
-        BLO_read_id_address(reader, NULL, &space_outliner->search_tse.id);
 
         if (space_outliner->treestore) {
           TreeStoreElem *tselem;
diff --git a/source/blender/blenkernel/intern/shader_fx.c b/source/blender/blenkernel/intern/shader_fx.c
index 51ebd232978..745bd2a97e6 100644
--- a/source/blender/blenkernel/intern/shader_fx.c
+++ b/source/blender/blenkernel/intern/shader_fx.c
@@ -70,7 +70,8 @@ ShaderFxData *BKE_shaderfx_new(int type)
   fx->type = type;
   fx->mode = eShaderFxMode_Realtime | eShaderFxMode_Render;
   fx->flag = eShaderFxFlag_OverrideLibrary_Local;
-  fx->ui_expand_flag = 1; /* Expand only the parent panel by default. */
+  /* Expand only the parent panel by default. */
+  fx->ui_expand_flag = UI_PANEL_DATA_EXPAND_ROOT;
 
   if (fxi->flags & eShaderFxTypeFlag_EnableInEditmode) {
     fx->mode |= eShaderFxMode_Editmode;
diff --git a/source/blender/blenkernel/intern/shrinkwrap.c b/source/blender/blenkernel/intern/shrinkwrap.c
index 7c7aa80402d..4b4e3bdcfa6 100644
--- a/source/blender/blenkernel/intern/shrinkwrap.c
+++ b/source/blender/blenkernel/intern/shrinkwrap.c
@@ -64,9 +64,9 @@ typedef struct ShrinkwrapCalcData {
   float (*vertexCos)[3]; /* vertexs being shrinkwraped */
   int numVerts;
 
-  struct MDeformVert *dvert; /* Pointer to mdeform array */
-  int vgroup;                /* Vertex group num */
-  bool invert_vgroup;        /* invert vertex group influence */
+  const struct MDeformVert *dvert; /* Pointer to mdeform array */
+  int vgroup;                      /* Vertex group num */
+  bool invert_vgroup;              /* invert vertex group influence */
 
   struct Mesh *target;                /* mesh we are shrinking to */
   struct SpaceTransform local2target; /* transform to move between local and target space */
@@ -113,6 +113,7 @@ bool BKE_shrinkwrap_init_tree(
   }
 
   data->mesh = mesh;
+  data->polys = BKE_mesh_polys(mesh);
 
   if (shrinkType == MOD_SHRINKWRAP_NEAREST_VERTEX) {
     data->bvh = BKE_bvhtree_from_mesh_get(&data->treeData, mesh, BVHTREE_FROM_VERTS, 2);
@@ -191,9 +192,9 @@ static void merge_vert_dir(ShrinkwrapBoundaryVertData *vdata,
 
 static ShrinkwrapBoundaryData *shrinkwrap_build_boundary_data(struct Mesh *mesh)
 {
-  const MLoop *mloop = mesh->mloop;
-  const MEdge *medge = mesh->medge;
-  const MVert *mvert = mesh->mvert;
+  const MVert *mvert = BKE_mesh_verts(mesh);
+  const MEdge *medge = BKE_mesh_edges(mesh);
+  const MLoop *mloop = BKE_mesh_loops(mesh);
 
   /* Count faces per edge (up to 2). */
   char *edge_mode = MEM_calloc_arrayN((size_t)mesh->totedge, sizeof(char), __func__);
@@ -666,7 +667,7 @@ static void shrinkwrap_calc_normal_projection(ShrinkwrapCalcData *calc)
   }
 
   if (calc->aux_target) {
-    auxMesh = BKE_modifier_get_evaluated_mesh_from_evaluated_object(calc->aux_target, false);
+    auxMesh = BKE_modifier_get_evaluated_mesh_from_evaluated_object(calc->aux_target);
     if (!auxMesh) {
       return;
     }
@@ -937,7 +938,7 @@ static void target_project_edge(const ShrinkwrapTreeData *tree,
                                 int eidx)
 {
   const BVHTreeFromMesh *data = &tree->treeData;
-  const MEdge *edge = &tree->mesh->medge[eidx];
+  const MEdge *edge = &data->edge[eidx];
   const float *vedge_co[2] = {data->vert[edge->v1].co, data->vert[edge->v2].co};
 
 #ifdef TRACE_TARGET_PROJECT
@@ -1179,7 +1180,7 @@ void BKE_shrinkwrap_compute_smooth_normal(const struct ShrinkwrapTreeData *tree,
   const float(*vert_normals)[3] = tree->treeData.vert_normals;
 
   /* Interpolate smooth normals if enabled. */
-  if ((tree->mesh->mpoly[tri->poly].flag & ME_SMOOTH) != 0) {
+  if ((tree->polys[tri->poly].flag & ME_SMOOTH) != 0) {
     const uint32_t vert_indices[3] = {treeData->loop[tri->tri[0]].v,
                                       treeData->loop[tri->tri[1]].v,
                                       treeData->loop[tri->tri[2]].v};
@@ -1369,7 +1370,7 @@ void shrinkwrapModifier_deform(ShrinkwrapModifierData *smd,
                                struct Scene *scene,
                                Object *ob,
                                Mesh *mesh,
-                               MDeformVert *dvert,
+                               const MDeformVert *dvert,
                                const int defgrp_index,
                                float (*vertexCos)[3],
                                int numVerts)
@@ -1397,7 +1398,7 @@ void shrinkwrapModifier_deform(ShrinkwrapModifierData *smd,
 
   if (smd->target != NULL) {
     Object *ob_target = DEG_get_evaluated_object(ctx->depsgraph, smd->target);
-    calc.target = BKE_modifier_get_evaluated_mesh_from_evaluated_object(ob_target, false);
+    calc.target = BKE_modifier_get_evaluated_mesh_from_evaluated_object(ob_target);
 
     /* TODO: there might be several "bugs" with non-uniform scales matrices
      * because it will no longer be nearest surface, not sphere projection
@@ -1411,7 +1412,7 @@ void shrinkwrapModifier_deform(ShrinkwrapModifierData *smd,
 
   if (mesh != NULL && smd->shrinkType == MOD_SHRINKWRAP_PROJECT) {
     /* Setup arrays to get vertexs positions, normals and deform weights */
-    calc.vert = mesh->mvert;
+    calc.vert = BKE_mesh_verts_for_write(mesh);
     calc.vert_normals = BKE_mesh_vertex_normals_ensure(mesh);
 
     /* Using vertexs positions/normals as if a subsurface was applied */
@@ -1574,7 +1575,7 @@ void BKE_shrinkwrap_remesh_target_project(Mesh *src_me, Mesh *target_me, Object
   calc.vgroup = -1;
   calc.target = target_me;
   calc.keepDist = ssmd.keepDist;
-  calc.vert = src_me->mvert;
+  calc.vert = BKE_mesh_verts_for_write(src_me);
   BLI_SPACE_TRANSFORM_SETUP(&calc.local2target, ob_target, ob_target);
 
   ShrinkwrapTreeData tree;
diff --git a/source/blender/blenkernel/intern/simulation.cc b/source/blender/blenkernel/intern/simulation.cc
index 260d67de4d8..9d4d6a4e350 100644
--- a/source/blender/blenkernel/intern/simulation.cc
+++ b/source/blender/blenkernel/intern/simulation.cc
@@ -51,8 +51,7 @@ static void simulation_init_data(ID *id)
 
   MEMCPY_STRUCT_AFTER(simulation, DNA_struct_default_get(Simulation), id);
 
-  bNodeTree *ntree = ntreeAddTree(nullptr, "Geometry Nodetree", ntreeType_Geometry->idname);
-  simulation->nodetree = ntree;
+  ntreeAddTreeEmbedded(nullptr, id, "Geometry Nodetree", ntreeType_Geometry->idname);
 }
 
 static void simulation_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const int flag)
@@ -68,6 +67,7 @@ static void simulation_copy_data(Main *bmain, ID *id_dst, const ID *id_src, cons
                    (ID *)simulation_src->nodetree,
                    (ID **)&simulation_dst->nodetree,
                    flag_private_id_data);
+    simulation_dst->nodetree->owner_id = &simulation_dst->id;
   }
 }
 
@@ -149,7 +149,7 @@ IDTypeInfo IDType_ID_SIM = {
     /* foreach_id */ simulation_foreach_id,
     /* foreach_cache */ nullptr,
     /* foreach_path */ nullptr,
-    /* owner_get */ nullptr,
+    /* owner_pointer_get */ nullptr,
 
     /* blend_write */ simulation_blend_write,
     /* blend_read_data */ simulation_blend_read_data,
diff --git a/source/blender/blenkernel/intern/softbody.c b/source/blender/blenkernel/intern/softbody.c
index afb8d5cb9f8..d1451353feb 100644
--- a/source/blender/blenkernel/intern/softbody.c
+++ b/source/blender/blenkernel/intern/softbody.c
@@ -567,7 +567,7 @@ static void ccd_update_deflector_hash(Depsgraph *depsgraph,
 static int count_mesh_quads(Mesh *me)
 {
   int a, result = 0;
-  const MPoly *mp = me->mpoly;
+  const MPoly *mp = BKE_mesh_polys(me);
 
   if (mp) {
     for (a = me->totpoly; a > 0; a--, mp++) {
@@ -591,8 +591,8 @@ static void add_mesh_quad_diag_springs(Object *ob)
 
     nofquads = count_mesh_quads(me);
     if (nofquads) {
-      const MLoop *mloop = me->mloop;
-      const MPoly *mp = me->mpoly;
+      const MLoop *mloop = BKE_mesh_loops(me);
+      const MPoly *mp = BKE_mesh_polys(me);
       BodySpring *bs;
 
       /* resize spring-array to hold additional quad springs */
@@ -2632,6 +2632,7 @@ static void springs_from_mesh(Object *ob)
   BodyPoint *bp;
   int a;
   float scale = 1.0f;
+  const MVert *verts = BKE_mesh_verts(me);
 
   sb = ob->soft;
   if (me && sb) {
@@ -2642,7 +2643,7 @@ static void springs_from_mesh(Object *ob)
     if (me->totvert) {
       bp = ob->soft->bpoint;
       for (a = 0; a < me->totvert; a++, bp++) {
-        copy_v3_v3(bp->origS, me->mvert[a].co);
+        copy_v3_v3(bp->origS, verts[a].co);
         mul_m4_v3(ob->obmat, bp->origS);
       }
     }
@@ -2663,7 +2664,7 @@ static void mesh_to_softbody(Object *ob)
 {
   SoftBody *sb;
   Mesh *me = ob->data;
-  MEdge *medge = me->medge;
+  const MEdge *medge = BKE_mesh_edges(me);
   BodyPoint *bp;
   BodySpring *bs;
   int a, totedge;
@@ -2683,10 +2684,11 @@ static void mesh_to_softbody(Object *ob)
   sb = ob->soft;
   bp = sb->bpoint;
 
-  defgroup_index = me->dvert ? (sb->vertgroup - 1) : -1;
-  defgroup_index_mass = me->dvert ? BKE_id_defgroup_name_index(&me->id, sb->namedVG_Mass) : -1;
-  defgroup_index_spring = me->dvert ? BKE_id_defgroup_name_index(&me->id, sb->namedVG_Spring_K) :
-                                      -1;
+  const MDeformVert *dvert = BKE_mesh_deform_verts(me);
+
+  defgroup_index = dvert ? (sb->vertgroup - 1) : -1;
+  defgroup_index_mass = dvert ? BKE_id_defgroup_name_index(&me->id, sb->namedVG_Mass) : -1;
+  defgroup_index_spring = dvert ? BKE_id_defgroup_name_index(&me->id, sb->namedVG_Spring_K) : -1;
 
   for (a = 0; a < me->totvert; a++, bp++) {
     /* get scalar values needed  *per vertex* from vertex group functions,
@@ -2699,7 +2701,7 @@ static void mesh_to_softbody(Object *ob)
       BLI_assert(bp->goal == sb->defgoal);
     }
     if ((ob->softflag & OB_SB_GOAL) && (defgroup_index != -1)) {
-      bp->goal *= BKE_defvert_find_weight(&me->dvert[a], defgroup_index);
+      bp->goal *= BKE_defvert_find_weight(&dvert[a], defgroup_index);
     }
 
     /* to proof the concept
@@ -2707,11 +2709,11 @@ static void mesh_to_softbody(Object *ob)
      */
 
     if (defgroup_index_mass != -1) {
-      bp->mass *= BKE_defvert_find_weight(&me->dvert[a], defgroup_index_mass);
+      bp->mass *= BKE_defvert_find_weight(&dvert[a], defgroup_index_mass);
     }
 
     if (defgroup_index_spring != -1) {
-      bp->springweight *= BKE_defvert_find_weight(&me->dvert[a], defgroup_index_spring);
+      bp->springweight *= BKE_defvert_find_weight(&dvert[a], defgroup_index_spring);
     }
   }
 
@@ -2753,19 +2755,23 @@ static void mesh_faces_to_scratch(Object *ob)
   MLoopTri *looptri, *lt;
   BodyFace *bodyface;
   int a;
+  const MVert *verts = BKE_mesh_verts(me);
+  const MPoly *polys = BKE_mesh_polys(me);
+  const MLoop *loops = BKE_mesh_loops(me);
+
   /* Allocate and copy faces. */
 
   sb->scratch->totface = poly_to_tri_count(me->totpoly, me->totloop);
   looptri = lt = MEM_mallocN(sizeof(*looptri) * sb->scratch->totface, __func__);
-  BKE_mesh_recalc_looptri(me->mloop, me->mpoly, me->mvert, me->totloop, me->totpoly, looptri);
+  BKE_mesh_recalc_looptri(loops, polys, verts, me->totloop, me->totpoly, looptri);
 
   bodyface = sb->scratch->bodyface = MEM_mallocN(sizeof(BodyFace) * sb->scratch->totface,
                                                  "SB_body_Faces");
 
   for (a = 0; a < sb->scratch->totface; a++, lt++, bodyface++) {
-    bodyface->v1 = me->mloop[lt->tri[0]].v;
-    bodyface->v2 = me->mloop[lt->tri[1]].v;
-    bodyface->v3 = me->mloop[lt->tri[2]].v;
+    bodyface->v1 = loops[lt->tri[0]].v;
+    bodyface->v2 = loops[lt->tri[1]].v;
+    bodyface->v3 = loops[lt->tri[2]].v;
     zero_v3(bodyface->ext_force);
     bodyface->ext_force[0] = bodyface->ext_force[1] = bodyface->ext_force[2] = 0.0f;
     bodyface->flag = 0;
diff --git a/source/blender/blenkernel/intern/sound.c b/source/blender/blenkernel/intern/sound.c
index f459b5a82ac..de1d0d3c30e 100644
--- a/source/blender/blenkernel/intern/sound.c
+++ b/source/blender/blenkernel/intern/sound.c
@@ -211,7 +211,7 @@ IDTypeInfo IDType_ID_SO = {
     .foreach_id = NULL,
     .foreach_cache = sound_foreach_cache,
     .foreach_path = sound_foreach_path,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = sound_blend_write,
     .blend_read_data = sound_blend_read_data,
@@ -756,7 +756,7 @@ void BKE_sound_remove_scene_sound(Scene *scene, void *handle)
   AUD_Sequence_remove(scene->sound_scene, handle);
 }
 
-void BKE_sound_mute_scene_sound(void *handle, char mute)
+void BKE_sound_mute_scene_sound(void *handle, bool mute)
 {
   AUD_SequenceEntry_setMuted(handle, mute);
 }
@@ -1346,7 +1346,7 @@ void *BKE_sound_add_scene_sound_defaults(Scene *UNUSED(scene), Sequence *UNUSED(
 void BKE_sound_remove_scene_sound(Scene *UNUSED(scene), void *UNUSED(handle))
 {
 }
-void BKE_sound_mute_scene_sound(void *UNUSED(handle), char UNUSED(mute))
+void BKE_sound_mute_scene_sound(void *UNUSED(handle), bool UNUSED(mute))
 {
 }
 void BKE_sound_move_scene_sound(const Scene *UNUSED(scene),
diff --git a/source/blender/blenkernel/intern/speaker.c b/source/blender/blenkernel/intern/speaker.c
index a8b76954a6f..3d49176d00a 100644
--- a/source/blender/blenkernel/intern/speaker.c
+++ b/source/blender/blenkernel/intern/speaker.c
@@ -94,7 +94,7 @@ IDTypeInfo IDType_ID_SPK = {
     .foreach_id = speaker_foreach_id,
     .foreach_cache = NULL,
     .foreach_path = NULL,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = speaker_blend_write,
     .blend_read_data = speaker_blend_read_data,
diff --git a/source/blender/blenkernel/intern/spline_base.cc b/source/blender/blenkernel/intern/spline_base.cc
deleted file mode 100644
index a674bf7800a..00000000000
--- a/source/blender/blenkernel/intern/spline_base.cc
+++ /dev/null
@@ -1,526 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-
-#include "BLI_array.hh"
-#include "BLI_generic_virtual_array.hh"
-#include "BLI_span.hh"
-#include "BLI_task.hh"
-#include "BLI_timeit.hh"
-
-#include "BKE_attribute_math.hh"
-#include "BKE_spline.hh"
-
-using blender::Array;
-using blender::float3;
-using blender::GMutableSpan;
-using blender::GSpan;
-using blender::GVArray;
-using blender::IndexRange;
-using blender::MutableSpan;
-using blender::Span;
-using blender::VArray;
-using blender::attribute_math::convert_to_static_type;
-using blender::bke::AttributeIDRef;
-using blender::bke::AttributeMetaData;
-
-CurveType Spline::type() const
-{
-  return type_;
-}
-
-void Spline::copy_base_settings(const Spline &src, Spline &dst)
-{
-  dst.normal_mode = src.normal_mode;
-  dst.is_cyclic_ = src.is_cyclic_;
-}
-
-static SplinePtr create_spline(const CurveType type)
-{
-  switch (type) {
-    case CURVE_TYPE_POLY:
-      return std::make_unique();
-    case CURVE_TYPE_BEZIER:
-      return std::make_unique();
-    case CURVE_TYPE_NURBS:
-      return std::make_unique();
-    case CURVE_TYPE_CATMULL_ROM:
-      BLI_assert_unreachable();
-      return {};
-  }
-  BLI_assert_unreachable();
-  return {};
-}
-
-SplinePtr Spline::copy() const
-{
-  SplinePtr dst = this->copy_without_attributes();
-  dst->attributes = this->attributes;
-  return dst;
-}
-
-SplinePtr Spline::copy_only_settings() const
-{
-  SplinePtr dst = create_spline(type_);
-  this->copy_base_settings(*this, *dst);
-  this->copy_settings(*dst);
-  return dst;
-}
-
-SplinePtr Spline::copy_without_attributes() const
-{
-  SplinePtr dst = this->copy_only_settings();
-  this->copy_data(*dst);
-
-  /* Though the attributes storage is empty, it still needs to know the correct size. */
-  dst->attributes.reallocate(dst->size());
-  return dst;
-}
-
-void Spline::translate(const blender::float3 &translation)
-{
-  for (float3 &position : this->positions()) {
-    position += translation;
-  }
-  this->mark_cache_invalid();
-}
-
-void Spline::transform(const blender::float4x4 &matrix)
-{
-  for (float3 &position : this->positions()) {
-    position = matrix * position;
-  }
-  this->mark_cache_invalid();
-}
-
-void Spline::reverse()
-{
-  this->positions().reverse();
-  this->radii().reverse();
-  this->tilts().reverse();
-
-  this->attributes.foreach_attribute(
-      [&](const AttributeIDRef &id, const AttributeMetaData &meta_data) {
-        std::optional attribute = this->attributes.get_for_write(id);
-        if (!attribute) {
-          BLI_assert_unreachable();
-          return false;
-        }
-        convert_to_static_type(meta_data.data_type, [&](auto dummy) {
-          using T = decltype(dummy);
-          attribute->typed().reverse();
-        });
-        return true;
-      },
-      ATTR_DOMAIN_POINT);
-
-  this->reverse_impl();
-  this->mark_cache_invalid();
-}
-
-int Spline::evaluated_edges_num() const
-{
-  const int eval_num = this->evaluated_points_num();
-  if (eval_num < 2) {
-    /* Two points are required for an edge. */
-    return 0;
-  }
-
-  return this->is_cyclic_ ? eval_num : eval_num - 1;
-}
-
-float Spline::length() const
-{
-  Span lengths = this->evaluated_lengths();
-  return lengths.is_empty() ? 0.0f : this->evaluated_lengths().last();
-}
-
-int Spline::segments_num() const
-{
-  const int num = this->size();
-
-  return is_cyclic_ ? num : num - 1;
-}
-
-bool Spline::is_cyclic() const
-{
-  return is_cyclic_;
-}
-
-void Spline::set_cyclic(const bool value)
-{
-  is_cyclic_ = value;
-}
-
-static void accumulate_lengths(Span positions,
-                               const bool is_cyclic,
-                               MutableSpan lengths)
-{
-  using namespace blender::math;
-
-  float length = 0.0f;
-  for (const int i : IndexRange(positions.size() - 1)) {
-    length += distance(positions[i], positions[i + 1]);
-    lengths[i] = length;
-  }
-  if (is_cyclic) {
-    lengths.last() = length + distance(positions.last(), positions.first());
-  }
-}
-
-Span Spline::evaluated_lengths() const
-{
-  if (!length_cache_dirty_) {
-    return evaluated_lengths_cache_;
-  }
-
-  std::lock_guard lock{length_cache_mutex_};
-  if (!length_cache_dirty_) {
-    return evaluated_lengths_cache_;
-  }
-
-  const int total = evaluated_edges_num();
-  evaluated_lengths_cache_.resize(total);
-  if (total != 0) {
-    Span positions = this->evaluated_positions();
-    accumulate_lengths(positions, is_cyclic_, evaluated_lengths_cache_);
-  }
-
-  length_cache_dirty_ = false;
-  return evaluated_lengths_cache_;
-}
-
-static float3 direction_bisect(const float3 &prev, const float3 &middle, const float3 &next)
-{
-  using namespace blender::math;
-
-  const float3 dir_prev = normalize(middle - prev);
-  const float3 dir_next = normalize(next - middle);
-
-  const float3 result = normalize(dir_prev + dir_next);
-  if (UNLIKELY(is_zero(result))) {
-    return float3(0.0f, 0.0f, 1.0f);
-  }
-  return result;
-}
-
-static void calculate_tangents(Span positions,
-                               const bool is_cyclic,
-                               MutableSpan tangents)
-{
-  using namespace blender::math;
-
-  if (positions.size() == 1) {
-    tangents.first() = float3(0.0f, 0.0f, 1.0f);
-    return;
-  }
-
-  for (const int i : IndexRange(1, positions.size() - 2)) {
-    tangents[i] = direction_bisect(positions[i - 1], positions[i], positions[i + 1]);
-  }
-
-  if (is_cyclic) {
-    const float3 &second_to_last = positions[positions.size() - 2];
-    const float3 &last = positions.last();
-    const float3 &first = positions.first();
-    const float3 &second = positions[1];
-    tangents.first() = direction_bisect(last, first, second);
-    tangents.last() = direction_bisect(second_to_last, last, first);
-  }
-  else {
-    tangents.first() = normalize(positions[1] - positions[0]);
-    tangents.last() = normalize(positions.last() - positions[positions.size() - 2]);
-  }
-}
-
-Span Spline::evaluated_tangents() const
-{
-  if (!tangent_cache_dirty_) {
-    return evaluated_tangents_cache_;
-  }
-
-  std::lock_guard lock{tangent_cache_mutex_};
-  if (!tangent_cache_dirty_) {
-    return evaluated_tangents_cache_;
-  }
-
-  const int eval_num = this->evaluated_points_num();
-  evaluated_tangents_cache_.resize(eval_num);
-
-  Span positions = this->evaluated_positions();
-
-  calculate_tangents(positions, is_cyclic_, evaluated_tangents_cache_);
-  this->correct_end_tangents();
-
-  tangent_cache_dirty_ = false;
-  return evaluated_tangents_cache_;
-}
-
-static float3 rotate_direction_around_axis(const float3 &direction,
-                                           const float3 &axis,
-                                           const float angle)
-{
-  using namespace blender::math;
-
-  BLI_ASSERT_UNIT_V3(direction);
-  BLI_ASSERT_UNIT_V3(axis);
-
-  const float3 axis_scaled = axis * dot(direction, axis);
-  const float3 diff = direction - axis_scaled;
-  const float3 cross = blender::math::cross(axis, diff);
-
-  return axis_scaled + diff * std::cos(angle) + cross * std::sin(angle);
-}
-
-static void calculate_normals_z_up(Span tangents, MutableSpan r_normals)
-{
-  using namespace blender::math;
-
-  BLI_assert(r_normals.size() == tangents.size());
-
-  /* Same as in `vec_to_quat`. */
-  const float epsilon = 1e-4f;
-  for (const int i : r_normals.index_range()) {
-    const float3 &tangent = tangents[i];
-    if (fabsf(tangent.x) + fabsf(tangent.y) < epsilon) {
-      r_normals[i] = {1.0f, 0.0f, 0.0f};
-    }
-    else {
-      r_normals[i] = normalize(float3(tangent.y, -tangent.x, 0.0f));
-    }
-  }
-}
-
-/**
- * Rotate the last normal in the same way the tangent has been rotated.
- */
-static float3 calculate_next_normal(const float3 &last_normal,
-                                    const float3 &last_tangent,
-                                    const float3 ¤t_tangent)
-{
-  using namespace blender::math;
-
-  if (is_zero(last_tangent) || is_zero(current_tangent)) {
-    return last_normal;
-  }
-  const float angle = angle_normalized_v3v3(last_tangent, current_tangent);
-  if (angle != 0.0) {
-    const float3 axis = normalize(cross(last_tangent, current_tangent));
-    return rotate_direction_around_axis(last_normal, axis, angle);
-  }
-  return last_normal;
-}
-
-static void calculate_normals_minimum(Span tangents,
-                                      const bool cyclic,
-                                      MutableSpan r_normals)
-{
-  using namespace blender::math;
-  BLI_assert(r_normals.size() == tangents.size());
-
-  if (r_normals.is_empty()) {
-    return;
-  }
-
-  const float epsilon = 1e-4f;
-
-  /* Set initial normal. */
-  const float3 &first_tangent = tangents[0];
-  if (fabs(first_tangent.x) + fabs(first_tangent.y) < epsilon) {
-    r_normals[0] = {1.0f, 0.0f, 0.0f};
-  }
-  else {
-    r_normals[0] = normalize(float3(first_tangent.y, -first_tangent.x, 0.0f));
-  }
-
-  /* Forward normal with minimum twist along the entire spline. */
-  for (const int i : IndexRange(1, r_normals.size() - 1)) {
-    r_normals[i] = calculate_next_normal(r_normals[i - 1], tangents[i - 1], tangents[i]);
-  }
-
-  if (!cyclic) {
-    return;
-  }
-
-  /* Compute how much the first normal deviates from the normal that has been forwarded along the
-   * entire cyclic spline. */
-  const float3 uncorrected_last_normal = calculate_next_normal(
-      r_normals.last(), tangents.last(), tangents[0]);
-  float correction_angle = angle_signed_on_axis_v3v3_v3(
-      r_normals[0], uncorrected_last_normal, tangents[0]);
-  if (correction_angle > M_PI) {
-    correction_angle = correction_angle - 2 * M_PI;
-  }
-
-  /* Gradually apply correction by rotating all normals slightly. */
-  const float angle_step = correction_angle / r_normals.size();
-  for (const int i : r_normals.index_range()) {
-    const float angle = angle_step * i;
-    r_normals[i] = rotate_direction_around_axis(r_normals[i], tangents[i], angle);
-  }
-}
-
-Span Spline::evaluated_normals() const
-{
-  if (!normal_cache_dirty_) {
-    return evaluated_normals_cache_;
-  }
-
-  std::lock_guard lock{normal_cache_mutex_};
-  if (!normal_cache_dirty_) {
-    return evaluated_normals_cache_;
-  }
-
-  const int eval_num = this->evaluated_points_num();
-  evaluated_normals_cache_.resize(eval_num);
-
-  Span tangents = this->evaluated_tangents();
-  MutableSpan normals = evaluated_normals_cache_;
-
-  /* Only Z up normals are supported at the moment. */
-  switch (this->normal_mode) {
-    case NORMAL_MODE_Z_UP: {
-      calculate_normals_z_up(tangents, normals);
-      break;
-    }
-    case NORMAL_MODE_MINIMUM_TWIST: {
-      calculate_normals_minimum(tangents, is_cyclic_, normals);
-      break;
-    }
-  }
-
-  /* Rotate the generated normals with the interpolated tilt data. */
-  VArray tilts = this->interpolate_to_evaluated(this->tilts());
-  for (const int i : normals.index_range()) {
-    normals[i] = rotate_direction_around_axis(normals[i], tangents[i], tilts[i]);
-  }
-
-  normal_cache_dirty_ = false;
-  return evaluated_normals_cache_;
-}
-
-Spline::LookupResult Spline::lookup_evaluated_factor(const float factor) const
-{
-  return this->lookup_evaluated_length(this->length() * factor);
-}
-
-Spline::LookupResult Spline::lookup_evaluated_length(const float length) const
-{
-  BLI_assert(length >= 0.0f && length <= this->length());
-
-  Span lengths = this->evaluated_lengths();
-
-  const float *offset = std::lower_bound(lengths.begin(), lengths.end(), length);
-  const int index = offset - lengths.begin();
-  const int next_index = (index == this->evaluated_points_num() - 1) ? 0 : index + 1;
-
-  const float previous_length = (index == 0) ? 0.0f : lengths[index - 1];
-  const float length_in_segment = length - previous_length;
-  const float segment_length = lengths[index] - previous_length;
-  const float factor = segment_length == 0.0f ? 0.0f : length_in_segment / segment_length;
-
-  return LookupResult{index, next_index, factor};
-}
-
-Array Spline::sample_uniform_index_factors(const int samples_num) const
-{
-  const Span lengths = this->evaluated_lengths();
-
-  BLI_assert(samples_num > 0);
-  Array samples(samples_num);
-
-  samples[0] = 0.0f;
-  if (samples_num == 1) {
-    return samples;
-  }
-
-  const float total_length = this->length();
-  const float sample_length = total_length / (samples_num - (is_cyclic_ ? 0 : 1));
-
-  /* Store the length at the previous evaluated point in a variable so it can
-   * start out at zero (the lengths array doesn't contain 0 for the first point). */
-  float prev_length = 0.0f;
-  int i_sample = 1;
-  for (const int i_evaluated : IndexRange(this->evaluated_edges_num())) {
-    const float length = lengths[i_evaluated];
-
-    /* Add every sample that fits in this evaluated edge. */
-    while ((sample_length * i_sample) < length && i_sample < samples_num) {
-      const float factor = (sample_length * i_sample - prev_length) / (length - prev_length);
-      samples[i_sample] = i_evaluated + factor;
-      i_sample++;
-    }
-
-    prev_length = length;
-  }
-
-  /* Zero lengths or float inaccuracies can cause invalid values, or simply
-   * skip some, so set the values that weren't completed in the main loop. */
-  for (const int i : IndexRange(i_sample, samples_num - i_sample)) {
-    samples[i] = float(samples_num);
-  }
-
-  if (!is_cyclic_) {
-    /* In rare cases this can prevent overflow of the stored index. */
-    samples.last() = lengths.size();
-  }
-
-  return samples;
-}
-
-Spline::LookupResult Spline::lookup_data_from_index_factor(const float index_factor) const
-{
-  const int eval_num = this->evaluated_points_num();
-
-  if (is_cyclic_) {
-    if (index_factor < eval_num) {
-      const int index = std::floor(index_factor);
-      const int next_index = (index < eval_num - 1) ? index + 1 : 0;
-      return LookupResult{index, next_index, index_factor - index};
-    }
-    return LookupResult{eval_num - 1, 0, 1.0f};
-  }
-
-  if (index_factor < eval_num - 1) {
-    const int index = std::floor(index_factor);
-    const int next_index = index + 1;
-    return LookupResult{index, next_index, index_factor - index};
-  }
-  return LookupResult{eval_num - 2, eval_num - 1, 1.0f};
-}
-
-void Spline::bounds_min_max(float3 &min, float3 &max, const bool use_evaluated) const
-{
-  Span positions = use_evaluated ? this->evaluated_positions() : this->positions();
-  for (const float3 &position : positions) {
-    minmax_v3v3_v3(min, max, position);
-  }
-}
-
-GVArray Spline::interpolate_to_evaluated(GSpan data) const
-{
-  return this->interpolate_to_evaluated(GVArray::ForSpan(data));
-}
-
-void Spline::sample_with_index_factors(const GVArray &src,
-                                       Span index_factors,
-                                       GMutableSpan dst) const
-{
-  BLI_assert(src.size() == this->evaluated_points_num());
-
-  blender::attribute_math::convert_to_static_type(src.type(), [&](auto dummy) {
-    using T = decltype(dummy);
-    const VArray src_typed = src.typed();
-    MutableSpan dst_typed = dst.typed();
-    if (src.size() == 1) {
-      dst_typed.fill(src_typed[0]);
-      return;
-    }
-    blender::threading::parallel_for(dst_typed.index_range(), 1024, [&](IndexRange range) {
-      for (const int i : range) {
-        const LookupResult interp = this->lookup_data_from_index_factor(index_factors[i]);
-        dst_typed[i] = blender::attribute_math::mix2(interp.factor,
-                                                     src_typed[interp.evaluated_index],
-                                                     src_typed[interp.next_evaluated_index]);
-      }
-    });
-  });
-}
diff --git a/source/blender/blenkernel/intern/spline_bezier.cc b/source/blender/blenkernel/intern/spline_bezier.cc
deleted file mode 100644
index 80515d0ef37..00000000000
--- a/source/blender/blenkernel/intern/spline_bezier.cc
+++ /dev/null
@@ -1,646 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-
-#include "BLI_array.hh"
-#include "BLI_span.hh"
-#include "BLI_task.hh"
-
-#include "BKE_spline.hh"
-
-using blender::Array;
-using blender::float3;
-using blender::GVArray;
-using blender::IndexRange;
-using blender::MutableSpan;
-using blender::Span;
-using blender::VArray;
-
-void BezierSpline::copy_settings(Spline &dst) const
-{
-  BezierSpline &bezier = static_cast(dst);
-  bezier.resolution_ = resolution_;
-}
-
-void BezierSpline::copy_data(Spline &dst) const
-{
-  BezierSpline &bezier = static_cast(dst);
-  bezier.positions_ = positions_;
-  bezier.handle_types_left_ = handle_types_left_;
-  bezier.handle_positions_left_ = handle_positions_left_;
-  bezier.handle_types_right_ = handle_types_right_;
-  bezier.handle_positions_right_ = handle_positions_right_;
-  bezier.radii_ = radii_;
-  bezier.tilts_ = tilts_;
-}
-
-int BezierSpline::size() const
-{
-  const int size = positions_.size();
-  BLI_assert(size == handle_types_left_.size());
-  BLI_assert(size == handle_positions_left_.size());
-  BLI_assert(size == handle_types_right_.size());
-  BLI_assert(size == handle_positions_right_.size());
-  BLI_assert(size == radii_.size());
-  BLI_assert(size == tilts_.size());
-  return size;
-}
-
-int BezierSpline::resolution() const
-{
-  return resolution_;
-}
-
-void BezierSpline::set_resolution(const int value)
-{
-  BLI_assert(value > 0);
-  resolution_ = value;
-  this->mark_cache_invalid();
-}
-
-void BezierSpline::resize(const int size)
-{
-  handle_types_left_.resize(size);
-  handle_positions_left_.resize(size);
-  positions_.resize(size);
-  handle_types_right_.resize(size);
-  handle_positions_right_.resize(size);
-  radii_.resize(size);
-  tilts_.resize(size);
-  this->mark_cache_invalid();
-  attributes.reallocate(size);
-}
-
-MutableSpan BezierSpline::positions()
-{
-  return positions_;
-}
-Span BezierSpline::positions() const
-{
-  return positions_;
-}
-MutableSpan BezierSpline::radii()
-{
-  return radii_;
-}
-Span BezierSpline::radii() const
-{
-  return radii_;
-}
-MutableSpan BezierSpline::tilts()
-{
-  return tilts_;
-}
-Span BezierSpline::tilts() const
-{
-  return tilts_;
-}
-Span BezierSpline::handle_types_left() const
-{
-  return handle_types_left_;
-}
-MutableSpan BezierSpline::handle_types_left()
-{
-  return handle_types_left_;
-}
-Span BezierSpline::handle_positions_left() const
-{
-  this->ensure_auto_handles();
-  return handle_positions_left_;
-}
-MutableSpan BezierSpline::handle_positions_left(const bool write_only)
-{
-  if (!write_only) {
-    this->ensure_auto_handles();
-  }
-  return handle_positions_left_;
-}
-
-Span BezierSpline::handle_types_right() const
-{
-  return handle_types_right_;
-}
-MutableSpan BezierSpline::handle_types_right()
-{
-  return handle_types_right_;
-}
-Span BezierSpline::handle_positions_right() const
-{
-  this->ensure_auto_handles();
-  return handle_positions_right_;
-}
-MutableSpan BezierSpline::handle_positions_right(const bool write_only)
-{
-  if (!write_only) {
-    this->ensure_auto_handles();
-  }
-  return handle_positions_right_;
-}
-
-void BezierSpline::reverse_impl()
-{
-  this->handle_positions_left().reverse();
-  this->handle_positions_right().reverse();
-  std::swap(this->handle_positions_left_, this->handle_positions_right_);
-
-  this->handle_types_left().reverse();
-  this->handle_types_right().reverse();
-  std::swap(this->handle_types_left_, this->handle_types_right_);
-}
-
-static float3 previous_position(Span positions, const bool cyclic, const int i)
-{
-  if (i == 0) {
-    if (cyclic) {
-      return positions[positions.size() - 1];
-    }
-    return 2.0f * positions[i] - positions[i + 1];
-  }
-  return positions[i - 1];
-}
-
-static float3 next_position(Span positions, const bool cyclic, const int i)
-{
-  if (i == positions.size() - 1) {
-    if (cyclic) {
-      return positions[0];
-    }
-    return 2.0f * positions[i] - positions[i - 1];
-  }
-  return positions[i + 1];
-}
-
-void BezierSpline::ensure_auto_handles() const
-{
-  if (!auto_handles_dirty_) {
-    return;
-  }
-
-  std::lock_guard lock{auto_handle_mutex_};
-  if (!auto_handles_dirty_) {
-    return;
-  }
-
-  if (this->size() == 1) {
-    auto_handles_dirty_ = false;
-    return;
-  }
-
-  for (const int i : IndexRange(this->size())) {
-    using namespace blender;
-
-    if (ELEM(BEZIER_HANDLE_AUTO, handle_types_left_[i], handle_types_right_[i])) {
-      const float3 prev_diff = positions_[i] - previous_position(positions_, is_cyclic_, i);
-      const float3 next_diff = next_position(positions_, is_cyclic_, i) - positions_[i];
-      float prev_len = math::length(prev_diff);
-      float next_len = math::length(next_diff);
-      if (prev_len == 0.0f) {
-        prev_len = 1.0f;
-      }
-      if (next_len == 0.0f) {
-        next_len = 1.0f;
-      }
-      const float3 dir = next_diff / next_len + prev_diff / prev_len;
-
-      /* This magic number is unfortunate, but comes from elsewhere in Blender. */
-      const float len = math::length(dir) * 2.5614f;
-      if (len != 0.0f) {
-        if (handle_types_left_[i] == BEZIER_HANDLE_AUTO) {
-          const float prev_len_clamped = std::min(prev_len, next_len * 5.0f);
-          handle_positions_left_[i] = positions_[i] + dir * -(prev_len_clamped / len);
-        }
-        if (handle_types_right_[i] == BEZIER_HANDLE_AUTO) {
-          const float next_len_clamped = std::min(next_len, prev_len * 5.0f);
-          handle_positions_right_[i] = positions_[i] + dir * (next_len_clamped / len);
-        }
-      }
-    }
-
-    if (handle_types_left_[i] == BEZIER_HANDLE_VECTOR) {
-      const float3 prev = previous_position(positions_, is_cyclic_, i);
-      handle_positions_left_[i] = math::interpolate(positions_[i], prev, 1.0f / 3.0f);
-    }
-
-    if (handle_types_right_[i] == BEZIER_HANDLE_VECTOR) {
-      const float3 next = next_position(positions_, is_cyclic_, i);
-      handle_positions_right_[i] = math::interpolate(positions_[i], next, 1.0f / 3.0f);
-    }
-  }
-
-  auto_handles_dirty_ = false;
-}
-
-void BezierSpline::translate(const blender::float3 &translation)
-{
-  for (float3 &position : this->positions()) {
-    position += translation;
-  }
-  for (float3 &handle_position : this->handle_positions_left()) {
-    handle_position += translation;
-  }
-  for (float3 &handle_position : this->handle_positions_right()) {
-    handle_position += translation;
-  }
-  this->mark_cache_invalid();
-}
-
-void BezierSpline::transform(const blender::float4x4 &matrix)
-{
-  for (float3 &position : this->positions()) {
-    position = matrix * position;
-  }
-  for (float3 &handle_position : this->handle_positions_left()) {
-    handle_position = matrix * handle_position;
-  }
-  for (float3 &handle_position : this->handle_positions_right()) {
-    handle_position = matrix * handle_position;
-  }
-  this->mark_cache_invalid();
-}
-
-static void set_handle_position(const float3 &position,
-                                const HandleType type,
-                                const HandleType type_other,
-                                const float3 &new_value,
-                                float3 &handle,
-                                float3 &handle_other)
-{
-  using namespace blender::math;
-
-  /* Don't bother when the handle positions are calculated automatically anyway. */
-  if (ELEM(type, BEZIER_HANDLE_AUTO, BEZIER_HANDLE_VECTOR)) {
-    return;
-  }
-
-  handle = new_value;
-  if (type_other == BEZIER_HANDLE_ALIGN) {
-    /* Keep track of the old length of the opposite handle. */
-    const float length = distance(handle_other, position);
-    /* Set the other handle to directly opposite from the current handle. */
-    const float3 dir = normalize(handle - position);
-    handle_other = position - dir * length;
-  }
-}
-
-void BezierSpline::set_handle_position_right(const int index, const blender::float3 &value)
-{
-  set_handle_position(positions_[index],
-                      static_cast(handle_types_right_[index]),
-                      static_cast(handle_types_left_[index]),
-                      value,
-                      handle_positions_right_[index],
-                      handle_positions_left_[index]);
-}
-
-void BezierSpline::set_handle_position_left(const int index, const blender::float3 &value)
-{
-  set_handle_position(positions_[index],
-                      static_cast(handle_types_right_[index]),
-                      static_cast(handle_types_left_[index]),
-                      value,
-                      handle_positions_left_[index],
-                      handle_positions_right_[index]);
-}
-
-bool BezierSpline::point_is_sharp(const int index) const
-{
-  return ELEM(handle_types_left_[index], BEZIER_HANDLE_VECTOR, BEZIER_HANDLE_FREE) ||
-         ELEM(handle_types_right_[index], BEZIER_HANDLE_VECTOR, BEZIER_HANDLE_FREE);
-}
-
-bool BezierSpline::segment_is_vector(const int index) const
-{
-  /* Two control points are necessary to form a segment, that should be checked by the caller. */
-  BLI_assert(this->size() > 1);
-
-  if (index == this->size() - 1) {
-    if (is_cyclic_) {
-      return handle_types_right_.last() == BEZIER_HANDLE_VECTOR &&
-             handle_types_left_.first() == BEZIER_HANDLE_VECTOR;
-    }
-    /* There is actually no segment in this case, but it's nice to avoid
-     * having a special case for the last segment in calling code. */
-    return true;
-  }
-  return handle_types_right_[index] == BEZIER_HANDLE_VECTOR &&
-         handle_types_left_[index + 1] == BEZIER_HANDLE_VECTOR;
-}
-
-void BezierSpline::mark_cache_invalid()
-{
-  offset_cache_dirty_ = true;
-  position_cache_dirty_ = true;
-  mapping_cache_dirty_ = true;
-  tangent_cache_dirty_ = true;
-  normal_cache_dirty_ = true;
-  length_cache_dirty_ = true;
-  auto_handles_dirty_ = true;
-}
-
-int BezierSpline::evaluated_points_num() const
-{
-  BLI_assert(this->size() > 0);
-  return this->control_point_offsets().last();
-}
-
-void BezierSpline::correct_end_tangents() const
-{
-  using namespace blender::math;
-  if (is_cyclic_) {
-    return;
-  }
-
-  MutableSpan tangents(evaluated_tangents_cache_);
-
-  if (handle_positions_right_.first() != positions_.first()) {
-    tangents.first() = normalize(handle_positions_right_.first() - positions_.first());
-  }
-  if (handle_positions_left_.last() != positions_.last()) {
-    tangents.last() = normalize(positions_.last() - handle_positions_left_.last());
-  }
-}
-
-BezierSpline::InsertResult BezierSpline::calculate_segment_insertion(const int index,
-                                                                     const int next_index,
-                                                                     const float parameter)
-{
-  using namespace blender::math;
-
-  BLI_assert(parameter <= 1.0f && parameter >= 0.0f);
-  BLI_assert(ELEM(next_index, 0, index + 1));
-  const float3 &point_prev = positions_[index];
-  const float3 &handle_prev = handle_positions_right_[index];
-  const float3 &handle_next = handle_positions_left_[next_index];
-  const float3 &point_next = positions_[next_index];
-  const float3 center_point = interpolate(handle_prev, handle_next, parameter);
-
-  BezierSpline::InsertResult result;
-  result.handle_prev = interpolate(point_prev, handle_prev, parameter);
-  result.handle_next = interpolate(handle_next, point_next, parameter);
-  result.left_handle = interpolate(result.handle_prev, center_point, parameter);
-  result.right_handle = interpolate(center_point, result.handle_next, parameter);
-  result.position = interpolate(result.left_handle, result.right_handle, parameter);
-  return result;
-}
-
-static void bezier_forward_difference_3d(const float3 &point_0,
-                                         const float3 &point_1,
-                                         const float3 &point_2,
-                                         const float3 &point_3,
-                                         MutableSpan result)
-{
-  BLI_assert(result.size() > 0);
-  const float inv_len = 1.0f / static_cast(result.size());
-  const float inv_len_squared = inv_len * inv_len;
-  const float inv_len_cubed = inv_len_squared * inv_len;
-
-  const float3 rt1 = 3.0f * (point_1 - point_0) * inv_len;
-  const float3 rt2 = 3.0f * (point_0 - 2.0f * point_1 + point_2) * inv_len_squared;
-  const float3 rt3 = (point_3 - point_0 + 3.0f * (point_1 - point_2)) * inv_len_cubed;
-
-  float3 q0 = point_0;
-  float3 q1 = rt1 + rt2 + rt3;
-  float3 q2 = 2.0f * rt2 + 6.0f * rt3;
-  float3 q3 = 6.0f * rt3;
-  for (const int i : result.index_range()) {
-    result[i] = q0;
-    q0 += q1;
-    q1 += q2;
-    q2 += q3;
-  }
-}
-
-void BezierSpline::evaluate_segment(const int index,
-                                    const int next_index,
-                                    MutableSpan positions) const
-{
-  if (this->segment_is_vector(index)) {
-    BLI_assert(positions.size() == 1);
-    positions.first() = positions_[index];
-  }
-  else {
-    bezier_forward_difference_3d(positions_[index],
-                                 handle_positions_right_[index],
-                                 handle_positions_left_[next_index],
-                                 positions_[next_index],
-                                 positions);
-  }
-}
-
-Span BezierSpline::control_point_offsets() const
-{
-  if (!offset_cache_dirty_) {
-    return offset_cache_;
-  }
-
-  std::lock_guard lock{offset_cache_mutex_};
-  if (!offset_cache_dirty_) {
-    return offset_cache_;
-  }
-
-  const int size = this->size();
-  offset_cache_.resize(size + 1);
-
-  MutableSpan offsets = offset_cache_;
-  if (size == 1) {
-    offsets.first() = 0;
-    offsets.last() = 1;
-  }
-  else {
-    int offset = 0;
-    for (const int i : IndexRange(size)) {
-      offsets[i] = offset;
-      offset += this->segment_is_vector(i) ? 1 : resolution_;
-    }
-    offsets.last() = offset;
-  }
-
-  offset_cache_dirty_ = false;
-  return offsets;
-}
-
-static void calculate_mappings_linear_resolution(Span offsets,
-                                                 const int size,
-                                                 const int resolution,
-                                                 const bool is_cyclic,
-                                                 MutableSpan r_mappings)
-{
-  const float first_segment_len_inv = 1.0f / offsets[1];
-  for (const int i : IndexRange(0, offsets[1])) {
-    r_mappings[i] = i * first_segment_len_inv;
-  }
-
-  const int grain_size = std::max(2048 / resolution, 1);
-  blender::threading::parallel_for(IndexRange(1, size - 2), grain_size, [&](IndexRange range) {
-    for (const int i_control_point : range) {
-      const int segment_len = offsets[i_control_point + 1] - offsets[i_control_point];
-      const float segment_len_inv = 1.0f / segment_len;
-      for (const int i : IndexRange(segment_len)) {
-        r_mappings[offsets[i_control_point] + i] = i_control_point + i * segment_len_inv;
-      }
-    }
-  });
-
-  if (is_cyclic) {
-    const int last_segment_len = offsets[size] - offsets[size - 1];
-    const float last_segment_len_inv = 1.0f / last_segment_len;
-    for (const int i : IndexRange(last_segment_len)) {
-      r_mappings[offsets[size - 1] + i] = size - 1 + i * last_segment_len_inv;
-    }
-  }
-  else {
-    r_mappings.last() = size - 1;
-  }
-}
-
-Span BezierSpline::evaluated_mappings() const
-{
-  if (!mapping_cache_dirty_) {
-    return evaluated_mapping_cache_;
-  }
-
-  std::lock_guard lock{mapping_cache_mutex_};
-  if (!mapping_cache_dirty_) {
-    return evaluated_mapping_cache_;
-  }
-
-  const int num = this->size();
-  const int eval_num = this->evaluated_points_num();
-  evaluated_mapping_cache_.resize(eval_num);
-  MutableSpan mappings = evaluated_mapping_cache_;
-
-  if (eval_num == 1) {
-    mappings.first() = 0.0f;
-    mapping_cache_dirty_ = false;
-    return mappings;
-  }
-
-  Span offsets = this->control_point_offsets();
-
-  blender::threading::isolate_task([&]() {
-    /* Isolate the task, since this is function is multi-threaded and holds a lock. */
-    calculate_mappings_linear_resolution(offsets, num, resolution_, is_cyclic_, mappings);
-  });
-
-  mapping_cache_dirty_ = false;
-  return mappings;
-}
-
-Span BezierSpline::evaluated_positions() const
-{
-  if (!position_cache_dirty_) {
-    return evaluated_position_cache_;
-  }
-
-  std::lock_guard lock{position_cache_mutex_};
-  if (!position_cache_dirty_) {
-    return evaluated_position_cache_;
-  }
-
-  const int num = this->size();
-  const int eval_num = this->evaluated_points_num();
-  evaluated_position_cache_.resize(eval_num);
-
-  MutableSpan positions = evaluated_position_cache_;
-
-  if (num == 1) {
-    /* Use a special case for single point splines to avoid checking in #evaluate_segment. */
-    BLI_assert(eval_num == 1);
-    positions.first() = positions_.first();
-    position_cache_dirty_ = false;
-    return positions;
-  }
-
-  this->ensure_auto_handles();
-
-  Span offsets = this->control_point_offsets();
-
-  const int grain_size = std::max(512 / resolution_, 1);
-  blender::threading::isolate_task([&]() {
-    /* Isolate the task, since this is function is multi-threaded and holds a lock. */
-    blender::threading::parallel_for(IndexRange(num - 1), grain_size, [&](IndexRange range) {
-      for (const int i : range) {
-        this->evaluate_segment(i, i + 1, positions.slice(offsets[i], offsets[i + 1] - offsets[i]));
-      }
-    });
-  });
-  if (is_cyclic_) {
-    this->evaluate_segment(
-        num - 1, 0, positions.slice(offsets[num - 1], offsets[num] - offsets[num - 1]));
-  }
-  else {
-    /* Since evaluating the bezier segment doesn't add the final point,
-     * it must be added manually in the non-cyclic case. */
-    positions.last() = positions_.last();
-  }
-
-  position_cache_dirty_ = false;
-  return positions;
-}
-
-BezierSpline::InterpolationData BezierSpline::interpolation_data_from_index_factor(
-    const float index_factor) const
-{
-  const int num = this->size();
-
-  if (is_cyclic_) {
-    if (index_factor < num) {
-      const int index = std::floor(index_factor);
-      const int next_index = (index < num - 1) ? index + 1 : 0;
-      return InterpolationData{index, next_index, index_factor - index};
-    }
-    return InterpolationData{num - 1, 0, 1.0f};
-  }
-
-  if (index_factor < num - 1) {
-    const int index = std::floor(index_factor);
-    const int next_index = index + 1;
-    return InterpolationData{index, next_index, index_factor - index};
-  }
-  return InterpolationData{num - 2, num - 1, 1.0f};
-}
-
-/* Use a spline argument to avoid adding this to the header. */
-template
-static void interpolate_to_evaluated_impl(const BezierSpline &spline,
-                                          const blender::VArray &src,
-                                          MutableSpan dst)
-{
-  BLI_assert(src.size() == spline.size());
-  BLI_assert(dst.size() == spline.evaluated_points_num());
-  Span mappings = spline.evaluated_mappings();
-
-  for (const int i : dst.index_range()) {
-    BezierSpline::InterpolationData interp = spline.interpolation_data_from_index_factor(
-        mappings[i]);
-
-    const T &value = src[interp.control_point_index];
-    const T &next_value = src[interp.next_control_point_index];
-
-    dst[i] = blender::attribute_math::mix2(interp.factor, value, next_value);
-  }
-}
-
-GVArray BezierSpline::interpolate_to_evaluated(const GVArray &src) const
-{
-  BLI_assert(src.size() == this->size());
-
-  if (src.is_single()) {
-    return src;
-  }
-
-  const int eval_num = this->evaluated_points_num();
-  if (eval_num == 1) {
-    return src;
-  }
-
-  GVArray new_varray;
-  blender::attribute_math::convert_to_static_type(src.type(), [&](auto dummy) {
-    using T = decltype(dummy);
-    if constexpr (!std::is_void_v>) {
-      Array values(eval_num);
-      interpolate_to_evaluated_impl(*this, src.typed(), values);
-      new_varray = VArray::ForContainer(std::move(values));
-    }
-  });
-
-  return new_varray;
-}
diff --git a/source/blender/blenkernel/intern/spline_nurbs.cc b/source/blender/blenkernel/intern/spline_nurbs.cc
deleted file mode 100644
index a7eeb82d854..00000000000
--- a/source/blender/blenkernel/intern/spline_nurbs.cc
+++ /dev/null
@@ -1,395 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-
-#include "BLI_array.hh"
-#include "BLI_span.hh"
-#include "BLI_virtual_array.hh"
-
-#include "BKE_attribute_math.hh"
-#include "BKE_spline.hh"
-
-using blender::Array;
-using blender::float3;
-using blender::GVArray;
-using blender::IndexRange;
-using blender::MutableSpan;
-using blender::Span;
-using blender::VArray;
-
-void NURBSpline::copy_settings(Spline &dst) const
-{
-  NURBSpline &nurbs = static_cast(dst);
-  nurbs.knots_mode = knots_mode;
-  nurbs.resolution_ = resolution_;
-  nurbs.order_ = order_;
-}
-
-void NURBSpline::copy_data(Spline &dst) const
-{
-  NURBSpline &nurbs = static_cast(dst);
-  nurbs.positions_ = positions_;
-  nurbs.weights_ = weights_;
-  nurbs.knots_ = knots_;
-  nurbs.knots_dirty_ = knots_dirty_;
-  nurbs.radii_ = radii_;
-  nurbs.tilts_ = tilts_;
-}
-
-int NURBSpline::size() const
-{
-  const int size = positions_.size();
-  BLI_assert(size == radii_.size());
-  BLI_assert(size == tilts_.size());
-  BLI_assert(size == weights_.size());
-  return size;
-}
-
-int NURBSpline::resolution() const
-{
-  return resolution_;
-}
-
-void NURBSpline::set_resolution(const int value)
-{
-  BLI_assert(value > 0);
-  resolution_ = value;
-  this->mark_cache_invalid();
-}
-
-uint8_t NURBSpline::order() const
-{
-  return order_;
-}
-
-void NURBSpline::set_order(const uint8_t value)
-{
-  BLI_assert(value >= 2 && value <= 6);
-  order_ = value;
-  this->mark_cache_invalid();
-}
-
-void NURBSpline::resize(const int size)
-{
-  positions_.resize(size);
-  radii_.resize(size);
-  tilts_.resize(size);
-  weights_.resize(size);
-  this->mark_cache_invalid();
-  attributes.reallocate(size);
-}
-
-MutableSpan NURBSpline::positions()
-{
-  return positions_;
-}
-Span NURBSpline::positions() const
-{
-  return positions_;
-}
-MutableSpan NURBSpline::radii()
-{
-  return radii_;
-}
-Span NURBSpline::radii() const
-{
-  return radii_;
-}
-MutableSpan NURBSpline::tilts()
-{
-  return tilts_;
-}
-Span NURBSpline::tilts() const
-{
-  return tilts_;
-}
-MutableSpan NURBSpline::weights()
-{
-  return weights_;
-}
-Span NURBSpline::weights() const
-{
-  return weights_;
-}
-
-void NURBSpline::reverse_impl()
-{
-  this->weights().reverse();
-}
-
-void NURBSpline::mark_cache_invalid()
-{
-  basis_cache_dirty_ = true;
-  position_cache_dirty_ = true;
-  tangent_cache_dirty_ = true;
-  normal_cache_dirty_ = true;
-  length_cache_dirty_ = true;
-}
-
-int NURBSpline::evaluated_points_num() const
-{
-  if (!this->check_valid_num_and_order()) {
-    return 0;
-  }
-  return resolution_ * this->segments_num();
-}
-
-void NURBSpline::correct_end_tangents() const
-{
-}
-
-bool NURBSpline::check_valid_num_and_order() const
-{
-  if (this->size() < order_) {
-    return false;
-  }
-
-  if (ELEM(this->knots_mode, NURBS_KNOT_MODE_BEZIER, NURBS_KNOT_MODE_ENDPOINT_BEZIER)) {
-    if (this->knots_mode == NURBS_KNOT_MODE_BEZIER && this->size() <= order_) {
-      return false;
-    }
-    return (!is_cyclic_ || this->size() % (order_ - 1) == 0);
-  }
-
-  return true;
-}
-
-int NURBSpline::knots_num() const
-{
-  const int num = this->size() + order_;
-  return is_cyclic_ ? num + order_ - 1 : num;
-}
-
-void NURBSpline::calculate_knots() const
-{
-  const KnotsMode mode = this->knots_mode;
-  const int order = order_;
-  const bool is_bezier = ELEM(mode, NURBS_KNOT_MODE_BEZIER, NURBS_KNOT_MODE_ENDPOINT_BEZIER);
-  const bool is_end_point = ELEM(mode, NURBS_KNOT_MODE_ENDPOINT, NURBS_KNOT_MODE_ENDPOINT_BEZIER);
-  /* Inner knots are always repeated once except on Bezier case. */
-  const int repeat_inner = is_bezier ? order - 1 : 1;
-  /* How many times to repeat 0.0 at the beginning of knot. */
-  const int head = is_end_point ? (order - (is_cyclic_ ? 1 : 0)) :
-                                  (is_bezier ? min_ii(2, repeat_inner) : 1);
-  /* Number of knots replicating widths of the starting knots.
-   * Covers both Cyclic and EndPoint cases. */
-  const int tail = is_cyclic_ ? 2 * order - 1 : (is_end_point ? order : 0);
-
-  knots_.resize(this->knots_num());
-  MutableSpan knots = knots_;
-
-  int r = head;
-  float current = 0.0f;
-
-  const int offset = is_end_point && is_cyclic_ ? 1 : 0;
-  if (offset) {
-    knots[0] = current;
-    current += 1.0f;
-  }
-
-  for (const int i : IndexRange(offset, knots.size() - offset - tail)) {
-    knots[i] = current;
-    r--;
-    if (r == 0) {
-      current += 1.0;
-      r = repeat_inner;
-    }
-  }
-
-  const int tail_index = knots.size() - tail;
-  for (const int i : IndexRange(tail)) {
-    knots[tail_index + i] = current + (knots[i] - knots[0]);
-  }
-}
-
-Span NURBSpline::knots() const
-{
-  if (!knots_dirty_) {
-    BLI_assert(knots_.size() == this->knots_num());
-    return knots_;
-  }
-
-  std::lock_guard lock{knots_mutex_};
-  if (!knots_dirty_) {
-    BLI_assert(knots_.size() == this->knots_num());
-    return knots_;
-  }
-
-  this->calculate_knots();
-
-  knots_dirty_ = false;
-
-  return knots_;
-}
-
-static void calculate_basis_for_point(const float parameter,
-                                      const int num,
-                                      const int degree,
-                                      const Span knots,
-                                      MutableSpan r_weights,
-                                      int &r_start_index)
-{
-  const int order = degree + 1;
-
-  int start = 0;
-  int end = 0;
-  for (const int i : IndexRange(num + degree)) {
-    const bool knots_equal = knots[i] == knots[i + 1];
-    if (knots_equal || parameter < knots[i] || parameter > knots[i + 1]) {
-      continue;
-    }
-
-    start = std::max(i - degree, 0);
-    end = i;
-    break;
-  }
-
-  Array buffer(order * 2, 0.0f);
-
-  buffer[end - start] = 1.0f;
-
-  for (const int i_order : IndexRange(2, degree)) {
-    if (end + i_order >= knots.size()) {
-      end = num + degree - i_order;
-    }
-    for (const int i : IndexRange(end - start + 1)) {
-      const int knot_index = start + i;
-
-      float new_basis = 0.0f;
-      if (buffer[i] != 0.0f) {
-        new_basis += ((parameter - knots[knot_index]) * buffer[i]) /
-                     (knots[knot_index + i_order - 1] - knots[knot_index]);
-      }
-
-      if (buffer[i + 1] != 0.0f) {
-        new_basis += ((knots[knot_index + i_order] - parameter) * buffer[i + 1]) /
-                     (knots[knot_index + i_order] - knots[knot_index + 1]);
-      }
-
-      buffer[i] = new_basis;
-    }
-  }
-
-  buffer.as_mutable_span().drop_front(end - start + 1).fill(0.0f);
-  r_weights.copy_from(buffer.as_span().take_front(order));
-  r_start_index = start;
-}
-
-const NURBSpline::BasisCache &NURBSpline::calculate_basis_cache() const
-{
-  if (!basis_cache_dirty_) {
-    return basis_cache_;
-  }
-
-  std::lock_guard lock{basis_cache_mutex_};
-  if (!basis_cache_dirty_) {
-    return basis_cache_;
-  }
-
-  const int num = this->size();
-  const int eval_num = this->evaluated_points_num();
-
-  const int order = this->order();
-  const int degree = order - 1;
-
-  basis_cache_.weights.resize(eval_num * order);
-  basis_cache_.start_indices.resize(eval_num);
-
-  if (eval_num == 0) {
-    return basis_cache_;
-  }
-
-  MutableSpan basis_weights(basis_cache_.weights);
-  MutableSpan basis_start_indices(basis_cache_.start_indices);
-
-  const Span control_weights = this->weights();
-  const Span knots = this->knots();
-
-  const int last_control_point_index = is_cyclic_ ? num + degree : num;
-
-  const float start = knots[degree];
-  const float end = knots[last_control_point_index];
-  const float step = (end - start) / this->evaluated_edges_num();
-  for (const int i : IndexRange(eval_num)) {
-    /* Clamp parameter due to floating point inaccuracy. */
-    const float parameter = std::clamp(start + step * i, knots[0], knots[num + degree]);
-
-    MutableSpan point_weights = basis_weights.slice(i * order, order);
-
-    calculate_basis_for_point(
-        parameter, last_control_point_index, degree, knots, point_weights, basis_start_indices[i]);
-
-    for (const int j : point_weights.index_range()) {
-      const int point_index = (basis_start_indices[i] + j) % num;
-      point_weights[j] *= control_weights[point_index];
-    }
-  }
-
-  basis_cache_dirty_ = false;
-  return basis_cache_;
-}
-
-template
-void interpolate_to_evaluated_impl(const NURBSpline::BasisCache &basis_cache,
-                                   const int order,
-                                   const blender::VArray &src,
-                                   MutableSpan dst)
-{
-  const int num = src.size();
-  blender::attribute_math::DefaultMixer mixer(dst);
-
-  for (const int i : dst.index_range()) {
-    Span point_weights = basis_cache.weights.as_span().slice(i * order, order);
-    const int start_index = basis_cache.start_indices[i];
-
-    for (const int j : point_weights.index_range()) {
-      const int point_index = (start_index + j) % num;
-      mixer.mix_in(i, src[point_index], point_weights[j]);
-    }
-  }
-
-  mixer.finalize();
-}
-
-GVArray NURBSpline::interpolate_to_evaluated(const GVArray &src) const
-{
-  BLI_assert(src.size() == this->size());
-
-  if (src.is_single()) {
-    return src;
-  }
-
-  const BasisCache &basis_cache = this->calculate_basis_cache();
-
-  GVArray new_varray;
-  blender::attribute_math::convert_to_static_type(src.type(), [&](auto dummy) {
-    using T = decltype(dummy);
-    if constexpr (!std::is_void_v>) {
-      Array values(this->evaluated_points_num());
-      interpolate_to_evaluated_impl(basis_cache, this->order(), src.typed(), values);
-      new_varray = VArray::ForContainer(std::move(values));
-    }
-  });
-
-  return new_varray;
-}
-
-Span NURBSpline::evaluated_positions() const
-{
-  if (!position_cache_dirty_) {
-    return evaluated_position_cache_;
-  }
-
-  std::lock_guard lock{position_cache_mutex_};
-  if (!position_cache_dirty_) {
-    return evaluated_position_cache_;
-  }
-
-  const int eval_num = this->evaluated_points_num();
-  evaluated_position_cache_.resize(eval_num);
-
-  /* TODO: Avoid copying the evaluated data from the temporary array. */
-  VArray evaluated = Spline::interpolate_to_evaluated(positions_.as_span());
-  evaluated.materialize(evaluated_position_cache_);
-
-  position_cache_dirty_ = false;
-  return evaluated_position_cache_;
-}
diff --git a/source/blender/blenkernel/intern/spline_poly.cc b/source/blender/blenkernel/intern/spline_poly.cc
deleted file mode 100644
index c3cc268c81c..00000000000
--- a/source/blender/blenkernel/intern/spline_poly.cc
+++ /dev/null
@@ -1,97 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-
-#include "BLI_span.hh"
-#include "BLI_virtual_array.hh"
-
-#include "BKE_spline.hh"
-
-using blender::float3;
-using blender::GVArray;
-using blender::MutableSpan;
-using blender::Span;
-
-void PolySpline::copy_settings(Spline &UNUSED(dst)) const
-{
-  /* Poly splines have no settings not covered by the base class. */
-}
-
-void PolySpline::copy_data(Spline &dst) const
-{
-  PolySpline &poly = static_cast(dst);
-  poly.positions_ = positions_;
-  poly.radii_ = radii_;
-  poly.tilts_ = tilts_;
-}
-
-int PolySpline::size() const
-{
-  const int size = positions_.size();
-  BLI_assert(size == radii_.size());
-  BLI_assert(size == tilts_.size());
-  return size;
-}
-
-void PolySpline::resize(const int size)
-{
-  positions_.resize(size);
-  radii_.resize(size);
-  tilts_.resize(size);
-  this->mark_cache_invalid();
-  attributes.reallocate(size);
-}
-
-MutableSpan PolySpline::positions()
-{
-  return positions_;
-}
-Span PolySpline::positions() const
-{
-  return positions_;
-}
-MutableSpan PolySpline::radii()
-{
-  return radii_;
-}
-Span PolySpline::radii() const
-{
-  return radii_;
-}
-MutableSpan PolySpline::tilts()
-{
-  return tilts_;
-}
-Span PolySpline::tilts() const
-{
-  return tilts_;
-}
-
-void PolySpline::reverse_impl()
-{
-}
-
-void PolySpline::mark_cache_invalid()
-{
-  tangent_cache_dirty_ = true;
-  normal_cache_dirty_ = true;
-  length_cache_dirty_ = true;
-}
-
-int PolySpline::evaluated_points_num() const
-{
-  return this->size();
-}
-
-void PolySpline::correct_end_tangents() const
-{
-}
-
-Span PolySpline::evaluated_positions() const
-{
-  return this->positions();
-}
-
-GVArray PolySpline::interpolate_to_evaluated(const GVArray &src) const
-{
-  BLI_assert(src.size() == this->size());
-  return src;
-}
diff --git a/source/blender/blenkernel/intern/studiolight.c b/source/blender/blenkernel/intern/studiolight.c
index f17450ac3f4..64f998ea67f 100644
--- a/source/blender/blenkernel/intern/studiolight.c
+++ b/source/blender/blenkernel/intern/studiolight.c
@@ -1166,19 +1166,21 @@ static void studiolight_add_files_from_datafolder(const int folder_id,
                                                   const char *subfolder,
                                                   int flag)
 {
-  struct direntry *dirs;
   const char *folder = BKE_appdir_folder_id(folder_id, subfolder);
-  if (folder) {
-    const uint dirs_num = BLI_filelist_dir_contents(folder, &dirs);
-    int i;
-    for (i = 0; i < dirs_num; i++) {
-      if (dirs[i].type & S_IFREG) {
-        studiolight_add_file(dirs[i].path, flag);
-      }
+  if (!folder) {
+    return;
+  }
+
+  struct direntry *dirs;
+  const uint dirs_num = BLI_filelist_dir_contents(folder, &dirs);
+  int i;
+  for (i = 0; i < dirs_num; i++) {
+    if (dirs[i].type & S_IFREG) {
+      studiolight_add_file(dirs[i].path, flag);
     }
-    BLI_filelist_free(dirs, dirs_num);
-    dirs = NULL;
   }
+  BLI_filelist_free(dirs, dirs_num);
+  dirs = NULL;
 }
 
 static int studiolight_flag_cmp_order(const StudioLight *sl)
diff --git a/source/blender/blenkernel/intern/subdiv_ccg.c b/source/blender/blenkernel/intern/subdiv_ccg.c
index c956ef09af3..03937b270bc 100644
--- a/source/blender/blenkernel/intern/subdiv_ccg.c
+++ b/source/blender/blenkernel/intern/subdiv_ccg.c
@@ -2043,6 +2043,11 @@ void BKE_subdiv_ccg_grid_hidden_ensure(SubdivCCG *subdiv_ccg, int grid_index)
   subdiv_ccg->grid_hidden[grid_index] = BLI_BITMAP_NEW(key.grid_area, __func__);
 }
 
+void BKE_subdiv_ccg_grid_hidden_free(SubdivCCG *subdiv_ccg, int grid_index)
+{
+  MEM_SAFE_FREE(subdiv_ccg->grid_hidden[grid_index]);
+}
+
 static void subdiv_ccg_coord_to_ptex_coord(const SubdivCCG *subdiv_ccg,
                                            const SubdivCCGCoord *coord,
                                            int *r_ptex_face_index,
diff --git a/source/blender/blenkernel/intern/subdiv_ccg_mask.c b/source/blender/blenkernel/intern/subdiv_ccg_mask.c
index 1290f1e0834..86891f0fa6e 100644
--- a/source/blender/blenkernel/intern/subdiv_ccg_mask.c
+++ b/source/blender/blenkernel/intern/subdiv_ccg_mask.c
@@ -17,6 +17,7 @@
 #include "BLI_utildefines.h"
 
 #include "BKE_customdata.h"
+#include "BKE_mesh.h"
 #include "BKE_subdiv.h"
 
 #include "MEM_guardedalloc.h"
@@ -102,7 +103,7 @@ static void free_mask_data(SubdivCCGMaskEvaluator *mask_evaluator)
 static int count_num_ptex_faces(const Mesh *mesh)
 {
   int num_ptex_faces = 0;
-  const MPoly *mpoly = mesh->mpoly;
+  const MPoly *mpoly = BKE_mesh_polys(mesh);
   for (int poly_index = 0; poly_index < mesh->totpoly; poly_index++) {
     const MPoly *poly = &mpoly[poly_index];
     num_ptex_faces += (poly->totloop == 4) ? 1 : poly->totloop;
@@ -113,7 +114,7 @@ static int count_num_ptex_faces(const Mesh *mesh)
 static void mask_data_init_mapping(SubdivCCGMaskEvaluator *mask_evaluator, const Mesh *mesh)
 {
   GridPaintMaskData *data = mask_evaluator->user_data;
-  const MPoly *mpoly = mesh->mpoly;
+  const MPoly *mpoly = BKE_mesh_polys(mesh);
   const int num_ptex_faces = count_num_ptex_faces(mesh);
   /* Allocate memory. */
   data->ptex_poly_corner = MEM_malloc_arrayN(
@@ -141,7 +142,7 @@ static void mask_data_init_mapping(SubdivCCGMaskEvaluator *mask_evaluator, const
 static void mask_init_data(SubdivCCGMaskEvaluator *mask_evaluator, const Mesh *mesh)
 {
   GridPaintMaskData *data = mask_evaluator->user_data;
-  data->mpoly = mesh->mpoly;
+  data->mpoly = BKE_mesh_polys(mesh);
   data->grid_paint_mask = CustomData_get_layer(&mesh->ldata, CD_GRID_PAINT_MASK);
   mask_data_init_mapping(mask_evaluator, mesh);
 }
diff --git a/source/blender/blenkernel/intern/subdiv_ccg_material.c b/source/blender/blenkernel/intern/subdiv_ccg_material.c
index cf49db15b7b..891e1d1b630 100644
--- a/source/blender/blenkernel/intern/subdiv_ccg_material.c
+++ b/source/blender/blenkernel/intern/subdiv_ccg_material.c
@@ -5,6 +5,7 @@
  * \ingroup bke
  */
 
+#include "BKE_mesh.h"
 #include "BKE_subdiv_ccg.h"
 
 #include "MEM_guardedalloc.h"
@@ -14,19 +15,19 @@
 
 typedef struct CCGMaterialFromMeshData {
   const Mesh *mesh;
+  const MPoly *polys;
+  const int *material_indices;
 } CCGMaterialFromMeshData;
 
 static DMFlagMat subdiv_ccg_material_flags_eval(
     SubdivCCGMaterialFlagsEvaluator *material_flags_evaluator, const int coarse_face_index)
 {
   CCGMaterialFromMeshData *data = (CCGMaterialFromMeshData *)material_flags_evaluator->user_data;
-  const Mesh *mesh = data->mesh;
-  BLI_assert(coarse_face_index < mesh->totpoly);
-  const MPoly *mpoly = mesh->mpoly;
-  const MPoly *poly = &mpoly[coarse_face_index];
+  BLI_assert(coarse_face_index < data->mesh->totpoly);
+  const MPoly *poly = &data->polys[coarse_face_index];
   DMFlagMat material_flags;
   material_flags.flag = poly->flag;
-  material_flags.mat_nr = poly->mat_nr;
+  material_flags.mat_nr = data->material_indices ? data->material_indices[coarse_face_index] : 0;
   return material_flags;
 }
 
@@ -42,6 +43,9 @@ void BKE_subdiv_ccg_material_flags_init_from_mesh(
   CCGMaterialFromMeshData *data = MEM_mallocN(sizeof(CCGMaterialFromMeshData),
                                               "ccg material eval");
   data->mesh = mesh;
+  data->material_indices = (const int *)CustomData_get_layer_named(
+      &mesh->pdata, CD_PROP_INT32, "material_index");
+  data->polys = BKE_mesh_polys(mesh);
   material_flags_evaluator->eval_material_flags = subdiv_ccg_material_flags_eval;
   material_flags_evaluator->free = subdiv_ccg_material_flags_free;
   material_flags_evaluator->user_data = data;
diff --git a/source/blender/blenkernel/intern/subdiv_converter_mesh.c b/source/blender/blenkernel/intern/subdiv_converter_mesh.c
index 12a5f00a68b..b13aec37c78 100644
--- a/source/blender/blenkernel/intern/subdiv_converter_mesh.c
+++ b/source/blender/blenkernel/intern/subdiv_converter_mesh.c
@@ -16,6 +16,7 @@
 #include "BLI_utildefines.h"
 
 #include "BKE_customdata.h"
+#include "BKE_mesh.h"
 #include "BKE_mesh_mapping.h"
 #include "BKE_subdiv.h"
 
@@ -33,6 +34,11 @@
 typedef struct ConverterStorage {
   SubdivSettings settings;
   const Mesh *mesh;
+  const MVert *verts;
+  const MEdge *edges;
+  const MPoly *polys;
+  const MLoop *loops;
+
   /* CustomData layer for vertex sharpnesses. */
   const float *cd_vertex_crease;
   /* Indexed by loop index, value denotes index of face-varying vertex
@@ -116,7 +122,7 @@ static int get_num_vertices(const OpenSubdiv_Converter *converter)
 static int get_num_face_vertices(const OpenSubdiv_Converter *converter, int manifold_face_index)
 {
   ConverterStorage *storage = converter->user_data;
-  return storage->mesh->mpoly[manifold_face_index].totloop;
+  return storage->polys[manifold_face_index].totloop;
 }
 
 static void get_face_vertices(const OpenSubdiv_Converter *converter,
@@ -124,8 +130,8 @@ static void get_face_vertices(const OpenSubdiv_Converter *converter,
                               int *manifold_face_vertices)
 {
   ConverterStorage *storage = converter->user_data;
-  const MPoly *poly = &storage->mesh->mpoly[manifold_face_index];
-  const MLoop *mloop = storage->mesh->mloop;
+  const MPoly *poly = &storage->polys[manifold_face_index];
+  const MLoop *mloop = storage->loops;
   for (int corner = 0; corner < poly->totloop; corner++) {
     manifold_face_vertices[corner] =
         storage->manifold_vertex_index[mloop[poly->loopstart + corner].v];
@@ -138,7 +144,7 @@ static void get_edge_vertices(const OpenSubdiv_Converter *converter,
 {
   ConverterStorage *storage = converter->user_data;
   const int edge_index = storage->manifold_edge_index_reverse[manifold_edge_index];
-  const MEdge *edge = &storage->mesh->medge[edge_index];
+  const MEdge *edge = &storage->edges[edge_index];
   manifold_edge_vertices[0] = storage->manifold_vertex_index[edge->v1];
   manifold_edge_vertices[1] = storage->manifold_vertex_index[edge->v2];
 }
@@ -155,7 +161,7 @@ static float get_edge_sharpness(const OpenSubdiv_Converter *converter, int manif
     return 0.0f;
   }
   const int edge_index = storage->manifold_edge_index_reverse[manifold_edge_index];
-  const MEdge *medge = storage->mesh->medge;
+  const MEdge *medge = storage->edges;
   return BKE_subdiv_crease_to_sharpness_char(medge[edge_index].crease);
 }
 
@@ -193,8 +199,6 @@ static void precalc_uv_layer(const OpenSubdiv_Converter *converter, const int la
 {
   ConverterStorage *storage = converter->user_data;
   const Mesh *mesh = storage->mesh;
-  const MPoly *mpoly = mesh->mpoly;
-  const MLoop *mloop = mesh->mloop;
   const MLoopUV *mloopuv = CustomData_get_layer_n(&mesh->ldata, CD_MLOOPUV, layer_index);
   const int num_poly = mesh->totpoly;
   const int num_vert = mesh->totvert;
@@ -205,7 +209,15 @@ static void precalc_uv_layer(const OpenSubdiv_Converter *converter, const int la
         mesh->totloop, sizeof(int), "loop uv vertex index");
   }
   UvVertMap *uv_vert_map = BKE_mesh_uv_vert_map_create(
-      mpoly, mloop, mloopuv, num_poly, num_vert, limit, false, true);
+      storage->polys,
+      (const bool *)CustomData_get_layer_named(&mesh->pdata, CD_PROP_BOOL, ".hide_poly"),
+      storage->loops,
+      mloopuv,
+      num_poly,
+      num_vert,
+      limit,
+      false,
+      true);
   /* NOTE: First UV vertex is supposed to be always marked as separate. */
   storage->num_uv_coordinates = -1;
   for (int vertex_index = 0; vertex_index < num_vert; vertex_index++) {
@@ -214,7 +226,7 @@ static void precalc_uv_layer(const OpenSubdiv_Converter *converter, const int la
       if (uv_vert->separate) {
         storage->num_uv_coordinates++;
       }
-      const MPoly *mp = &mpoly[uv_vert->poly_index];
+      const MPoly *mp = &storage->polys[uv_vert->poly_index];
       const int global_loop_index = mp->loopstart + uv_vert->loop_of_poly_index;
       storage->loop_uv_indices[global_loop_index] = storage->num_uv_coordinates;
       uv_vert = uv_vert->next;
@@ -242,7 +254,7 @@ static int get_face_corner_uv_index(const OpenSubdiv_Converter *converter,
                                     const int corner)
 {
   ConverterStorage *storage = converter->user_data;
-  const MPoly *mp = &storage->mesh->mpoly[face_index];
+  const MPoly *mp = &storage->polys[face_index];
   return storage->loop_uv_indices[mp->loopstart + corner];
 }
 
@@ -336,9 +348,9 @@ static void initialize_manifold_index_array(const BLI_bitmap *used_map,
 static void initialize_manifold_indices(ConverterStorage *storage)
 {
   const Mesh *mesh = storage->mesh;
-  const MEdge *medge = mesh->medge;
-  const MLoop *mloop = mesh->mloop;
-  const MPoly *mpoly = mesh->mpoly;
+  const MEdge *medge = storage->edges;
+  const MLoop *mloop = storage->loops;
+  const MPoly *mpoly = storage->polys;
   /* Set bits of elements which are not loose. */
   BLI_bitmap *vert_used_map = BLI_BITMAP_NEW(mesh->totvert, "vert used map");
   BLI_bitmap *edge_used_map = BLI_BITMAP_NEW(mesh->totedge, "edge used map");
@@ -381,6 +393,10 @@ static void init_user_data(OpenSubdiv_Converter *converter,
   ConverterStorage *user_data = MEM_mallocN(sizeof(ConverterStorage), __func__);
   user_data->settings = *settings;
   user_data->mesh = mesh;
+  user_data->verts = BKE_mesh_verts(mesh);
+  user_data->edges = BKE_mesh_edges(mesh);
+  user_data->polys = BKE_mesh_polys(mesh);
+  user_data->loops = BKE_mesh_loops(mesh);
   user_data->cd_vertex_crease = CustomData_get_layer(&mesh->vdata, CD_CREASE);
   user_data->loop_uv_indices = NULL;
   initialize_manifold_indices(user_data);
diff --git a/source/blender/blenkernel/intern/subdiv_displacement_multires.c b/source/blender/blenkernel/intern/subdiv_displacement_multires.c
index 0decb57bb38..398a4083ee2 100644
--- a/source/blender/blenkernel/intern/subdiv_displacement_multires.c
+++ b/source/blender/blenkernel/intern/subdiv_displacement_multires.c
@@ -18,6 +18,7 @@
 #include "BLI_utildefines.h"
 
 #include "BKE_customdata.h"
+#include "BKE_mesh.h"
 #include "BKE_multires.h"
 #include "BKE_subdiv_eval.h"
 
@@ -360,7 +361,7 @@ static void free_displacement(SubdivDisplacement *displacement)
 static int count_num_ptex_faces(const Mesh *mesh)
 {
   int num_ptex_faces = 0;
-  const MPoly *mpoly = mesh->mpoly;
+  const MPoly *mpoly = BKE_mesh_polys(mesh);
   for (int poly_index = 0; poly_index < mesh->totpoly; poly_index++) {
     const MPoly *poly = &mpoly[poly_index];
     num_ptex_faces += (poly->totloop == 4) ? 1 : poly->totloop;
@@ -371,7 +372,7 @@ static int count_num_ptex_faces(const Mesh *mesh)
 static void displacement_data_init_mapping(SubdivDisplacement *displacement, const Mesh *mesh)
 {
   MultiresDisplacementData *data = displacement->user_data;
-  const MPoly *mpoly = mesh->mpoly;
+  const MPoly *mpoly = BKE_mesh_polys(mesh);
   const int num_ptex_faces = count_num_ptex_faces(mesh);
   /* Allocate memory. */
   data->ptex_poly_corner = MEM_malloc_arrayN(
@@ -406,7 +407,7 @@ static void displacement_init_data(SubdivDisplacement *displacement,
   data->grid_size = BKE_subdiv_grid_size_from_level(mmd->totlvl);
   data->mesh = mesh;
   data->mmd = mmd;
-  data->mpoly = mesh->mpoly;
+  data->mpoly = BKE_mesh_polys(mesh);
   data->mdisps = CustomData_get_layer(&mesh->ldata, CD_MDISPS);
   data->face_ptex_offset = BKE_subdiv_face_ptex_offset_get(subdiv);
   data->is_initialized = false;
diff --git a/source/blender/blenkernel/intern/subdiv_eval.c b/source/blender/blenkernel/intern/subdiv_eval.c
index fda833ffd27..e6f24aa6ff8 100644
--- a/source/blender/blenkernel/intern/subdiv_eval.c
+++ b/source/blender/blenkernel/intern/subdiv_eval.c
@@ -16,6 +16,7 @@
 #include "BLI_utildefines.h"
 
 #include "BKE_customdata.h"
+#include "BKE_mesh.h"
 #include "BKE_subdiv.h"
 
 #include "MEM_guardedalloc.h"
@@ -34,8 +35,8 @@ static eOpenSubdivEvaluator opensubdiv_evalutor_from_subdiv_evaluator_type(
     case SUBDIV_EVALUATOR_TYPE_CPU: {
       return OPENSUBDIV_EVALUATOR_CPU;
     }
-    case SUBDIV_EVALUATOR_TYPE_GLSL_COMPUTE: {
-      return OPENSUBDIV_EVALUATOR_GLSL_COMPUTE;
+    case SUBDIV_EVALUATOR_TYPE_GPU: {
+      return OPENSUBDIV_EVALUATOR_GPU;
     }
   }
   BLI_assert_msg(0, "Unknown evaluator type");
@@ -80,9 +81,9 @@ static void set_coarse_positions(Subdiv *subdiv,
                                  const Mesh *mesh,
                                  const float (*coarse_vertex_cos)[3])
 {
-  const MVert *mvert = mesh->mvert;
-  const MLoop *mloop = mesh->mloop;
-  const MPoly *mpoly = mesh->mpoly;
+  const MVert *mvert = BKE_mesh_verts(mesh);
+  const MPoly *mpoly = BKE_mesh_polys(mesh);
+  const MLoop *mloop = BKE_mesh_loops(mesh);
   /* Mark vertices which needs new coordinates. */
   /* TODO(sergey): This is annoying to calculate this on every update,
    * maybe it's better to cache this mapping. Or make it possible to have
@@ -125,6 +126,7 @@ static void set_coarse_positions(Subdiv *subdiv,
 typedef struct FaceVaryingDataFromUVContext {
   OpenSubdiv_TopologyRefiner *topology_refiner;
   const Mesh *mesh;
+  const MPoly *polys;
   const MLoopUV *mloopuv;
   float (*buffer)[2];
   int layer_index;
@@ -137,8 +139,7 @@ static void set_face_varying_data_from_uv_task(void *__restrict userdata,
   FaceVaryingDataFromUVContext *ctx = userdata;
   OpenSubdiv_TopologyRefiner *topology_refiner = ctx->topology_refiner;
   const int layer_index = ctx->layer_index;
-  const Mesh *mesh = ctx->mesh;
-  const MPoly *mpoly = &mesh->mpoly[face_index];
+  const MPoly *mpoly = &ctx->polys[face_index];
   const MLoopUV *mluv = &ctx->mloopuv[mpoly->loopstart];
 
   /* TODO(sergey): OpenSubdiv's C-API converter can change winding of
@@ -171,6 +172,7 @@ static void set_face_varying_data_from_uv(Subdiv *subdiv,
   ctx.layer_index = layer_index;
   ctx.mloopuv = mluv;
   ctx.mesh = mesh;
+  ctx.polys = BKE_mesh_polys(mesh);
   ctx.buffer = buffer;
 
   TaskParallelSettings parallel_range_settings;
diff --git a/source/blender/blenkernel/intern/subdiv_foreach.c b/source/blender/blenkernel/intern/subdiv_foreach.c
index 80364561d01..faf531b0f5e 100644
--- a/source/blender/blenkernel/intern/subdiv_foreach.c
+++ b/source/blender/blenkernel/intern/subdiv_foreach.c
@@ -158,8 +158,8 @@ static void subdiv_foreach_ctx_count(SubdivForeachTaskContext *ctx)
   const int num_inner_vertices_per_noquad_patch = (no_quad_patch_resolution - 2) *
                                                   (no_quad_patch_resolution - 2);
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MLoop *coarse_mloop = coarse_mesh->mloop;
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
+  const MLoop *coarse_mloop = BKE_mesh_loops(coarse_mesh);
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
   ctx->num_subdiv_vertices = coarse_mesh->totvert;
   ctx->num_subdiv_edges = coarse_mesh->totedge * (num_subdiv_vertices_per_coarse_edge + 1);
   /* Calculate extra vertices and edges created by non-loose geometry. */
@@ -225,7 +225,7 @@ static void subdiv_foreach_ctx_init_offsets(SubdivForeachTaskContext *ctx)
   ctx->edge_inner_offset = ctx->edge_boundary_offset +
                            coarse_mesh->totedge * num_subdiv_edges_per_coarse_edge;
   /* "Indexed" offsets. */
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
   int vertex_offset = 0;
   int edge_offset = 0;
   int polygon_offset = 0;
@@ -301,8 +301,9 @@ static void subdiv_foreach_corner_vertices_regular_do(
 {
   const float weights[4][2] = {{0.0f, 0.0f}, {1.0f, 0.0f}, {1.0f, 1.0f}, {0.0f, 1.0f}};
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MLoop *coarse_mloop = coarse_mesh->mloop;
-  const int coarse_poly_index = coarse_poly - coarse_mesh->mpoly;
+  const MLoop *coarse_mloop = BKE_mesh_loops(coarse_mesh);
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
+  const int coarse_poly_index = coarse_poly - coarse_mpoly;
   const int ptex_face_index = ctx->face_ptex_offset[coarse_poly_index];
   for (int corner = 0; corner < coarse_poly->totloop; corner++) {
     const MLoop *coarse_loop = &coarse_mloop[coarse_poly->loopstart + corner];
@@ -342,8 +343,9 @@ static void subdiv_foreach_corner_vertices_special_do(
     bool check_usage)
 {
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MLoop *coarse_mloop = coarse_mesh->mloop;
-  const int coarse_poly_index = coarse_poly - coarse_mesh->mpoly;
+  const MLoop *coarse_mloop = BKE_mesh_loops(coarse_mesh);
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
+  const int coarse_poly_index = coarse_poly - coarse_mpoly;
   int ptex_face_index = ctx->face_ptex_offset[coarse_poly_index];
   for (int corner = 0; corner < coarse_poly->totloop; corner++, ptex_face_index++) {
     const MLoop *coarse_loop = &coarse_mloop[coarse_poly->loopstart + corner];
@@ -407,7 +409,7 @@ static void subdiv_foreach_every_corner_vertices(SubdivForeachTaskContext *ctx,
     return;
   }
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
   for (int poly_index = 0; poly_index < coarse_mesh->totpoly; poly_index++) {
     const MPoly *coarse_poly = &coarse_mpoly[poly_index];
     if (coarse_poly->totloop == 4) {
@@ -432,11 +434,11 @@ static void subdiv_foreach_edge_vertices_regular_do(SubdivForeachTaskContext *ct
   const float inv_resolution_1 = 1.0f / (float)resolution_1;
   const int num_subdiv_vertices_per_coarse_edge = resolution - 2;
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MEdge *coarse_medge = coarse_mesh->medge;
-  const MLoop *coarse_mloop = coarse_mesh->mloop;
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
+  const MEdge *coarse_medge = BKE_mesh_edges(coarse_mesh);
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
+  const MLoop *coarse_mloop = BKE_mesh_loops(coarse_mesh);
   const int coarse_poly_index = coarse_poly - coarse_mpoly;
-  const int poly_index = coarse_poly - coarse_mesh->mpoly;
+  const int poly_index = coarse_poly - coarse_mpoly;
   const int ptex_face_index = ctx->face_ptex_offset[poly_index];
   for (int corner = 0; corner < coarse_poly->totloop; corner++) {
     const MLoop *coarse_loop = &coarse_mloop[coarse_poly->loopstart + corner];
@@ -499,11 +501,11 @@ static void subdiv_foreach_edge_vertices_special_do(SubdivForeachTaskContext *ct
   const int num_vertices_per_ptex_edge = ((resolution >> 1) + 1);
   const float inv_ptex_resolution_1 = 1.0f / (float)(num_vertices_per_ptex_edge - 1);
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MEdge *coarse_medge = coarse_mesh->medge;
-  const MLoop *coarse_mloop = coarse_mesh->mloop;
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
+  const MEdge *coarse_medge = BKE_mesh_edges(coarse_mesh);
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
+  const MLoop *coarse_mloop = BKE_mesh_loops(coarse_mesh);
   const int coarse_poly_index = coarse_poly - coarse_mpoly;
-  const int poly_index = coarse_poly - coarse_mesh->mpoly;
+  const int poly_index = coarse_poly - coarse_mpoly;
   const int ptex_face_start_index = ctx->face_ptex_offset[poly_index];
   int ptex_face_index = ptex_face_start_index;
   for (int corner = 0; corner < coarse_poly->totloop; corner++, ptex_face_index++) {
@@ -595,7 +597,7 @@ static void subdiv_foreach_every_edge_vertices(SubdivForeachTaskContext *ctx, vo
     return;
   }
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
   for (int poly_index = 0; poly_index < coarse_mesh->totpoly; poly_index++) {
     const MPoly *coarse_poly = &coarse_mpoly[poly_index];
     if (coarse_poly->totloop == 4) {
@@ -616,7 +618,8 @@ static void subdiv_foreach_inner_vertices_regular(SubdivForeachTaskContext *ctx,
   const int resolution = ctx->settings->resolution;
   const float inv_resolution_1 = 1.0f / (float)(resolution - 1);
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const int coarse_poly_index = coarse_poly - coarse_mesh->mpoly;
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
+  const int coarse_poly_index = coarse_poly - coarse_mpoly;
   const int ptex_face_index = ctx->face_ptex_offset[coarse_poly_index];
   const int start_vertex_index = ctx->subdiv_vertex_offset[coarse_poly_index];
   int subdiv_vertex_index = ctx->vertices_inner_offset + start_vertex_index;
@@ -644,7 +647,8 @@ static void subdiv_foreach_inner_vertices_special(SubdivForeachTaskContext *ctx,
   const int ptex_face_resolution = ptex_face_resolution_get(coarse_poly, resolution);
   const float inv_ptex_face_resolution_1 = 1.0f / (float)(ptex_face_resolution - 1);
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const int coarse_poly_index = coarse_poly - coarse_mesh->mpoly;
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
+  const int coarse_poly_index = coarse_poly - coarse_mpoly;
   int ptex_face_index = ctx->face_ptex_offset[coarse_poly_index];
   const int start_vertex_index = ctx->subdiv_vertex_offset[coarse_poly_index];
   int subdiv_vertex_index = ctx->vertices_inner_offset + start_vertex_index;
@@ -691,7 +695,7 @@ static void subdiv_foreach_inner_vertices(SubdivForeachTaskContext *ctx,
 static void subdiv_foreach_vertices(SubdivForeachTaskContext *ctx, void *tls, const int poly_index)
 {
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
   const MPoly *coarse_poly = &coarse_mpoly[poly_index];
   if (ctx->foreach_context->vertex_inner != NULL) {
     subdiv_foreach_inner_vertices(ctx, tls, coarse_poly);
@@ -775,9 +779,9 @@ static void subdiv_foreach_edges_all_patches_regular(SubdivForeachTaskContext *c
                                                      const MPoly *coarse_poly)
 {
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MEdge *coarse_medge = coarse_mesh->medge;
-  const MLoop *coarse_mloop = coarse_mesh->mloop;
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
+  const MEdge *coarse_medge = BKE_mesh_edges(coarse_mesh);
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
+  const MLoop *coarse_mloop = BKE_mesh_loops(coarse_mesh);
   const int poly_index = coarse_poly - coarse_mpoly;
   const int resolution = ctx->settings->resolution;
   const int start_vertex_index = ctx->vertices_inner_offset +
@@ -856,9 +860,9 @@ static void subdiv_foreach_edges_all_patches_special(SubdivForeachTaskContext *c
                                                      const MPoly *coarse_poly)
 {
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MEdge *coarse_medge = coarse_mesh->medge;
-  const MLoop *coarse_mloop = coarse_mesh->mloop;
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
+  const MEdge *coarse_medge = BKE_mesh_edges(coarse_mesh);
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
+  const MLoop *coarse_mloop = BKE_mesh_loops(coarse_mesh);
   const int poly_index = coarse_poly - coarse_mpoly;
   const int resolution = ctx->settings->resolution;
   const int ptex_face_resolution = ptex_face_resolution_get(coarse_poly, resolution);
@@ -984,7 +988,7 @@ static void subdiv_foreach_edges_all_patches(SubdivForeachTaskContext *ctx,
 static void subdiv_foreach_edges(SubdivForeachTaskContext *ctx, void *tls, int poly_index)
 {
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
   const MPoly *coarse_poly = &coarse_mpoly[poly_index];
   subdiv_foreach_edges_all_patches(ctx, tls, coarse_poly);
 }
@@ -994,7 +998,7 @@ static void subdiv_foreach_boundary_edges(SubdivForeachTaskContext *ctx,
                                           int coarse_edge_index)
 {
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MEdge *coarse_medge = coarse_mesh->medge;
+  const MEdge *coarse_medge = BKE_mesh_edges(coarse_mesh);
   const MEdge *coarse_edge = &coarse_medge[coarse_edge_index];
   const int resolution = ctx->settings->resolution;
   const int num_subdiv_vertices_per_coarse_edge = resolution - 2;
@@ -1125,9 +1129,9 @@ static void subdiv_foreach_loops_regular(SubdivForeachTaskContext *ctx,
   const int resolution = ctx->settings->resolution;
   /* Base/coarse mesh information. */
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MEdge *coarse_medge = coarse_mesh->medge;
-  const MLoop *coarse_mloop = coarse_mesh->mloop;
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
+  const MEdge *coarse_medge = BKE_mesh_edges(coarse_mesh);
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
+  const MLoop *coarse_mloop = BKE_mesh_loops(coarse_mesh);
   const int coarse_poly_index = coarse_poly - coarse_mpoly;
   const int ptex_resolution = ptex_face_resolution_get(coarse_poly, resolution);
   const int ptex_inner_resolution = ptex_resolution - 2;
@@ -1319,9 +1323,9 @@ static void subdiv_foreach_loops_special(SubdivForeachTaskContext *ctx,
   const int resolution = ctx->settings->resolution;
   /* Base/coarse mesh information. */
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MEdge *coarse_medge = coarse_mesh->medge;
-  const MLoop *coarse_mloop = coarse_mesh->mloop;
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
+  const MEdge *coarse_medge = BKE_mesh_edges(coarse_mesh);
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
+  const MLoop *coarse_mloop = BKE_mesh_loops(coarse_mesh);
   const int coarse_poly_index = coarse_poly - coarse_mpoly;
   const int ptex_face_resolution = ptex_face_resolution_get(coarse_poly, resolution);
   const int ptex_face_inner_resolution = ptex_face_resolution - 2;
@@ -1654,7 +1658,7 @@ static void subdiv_foreach_loops_special(SubdivForeachTaskContext *ctx,
 static void subdiv_foreach_loops(SubdivForeachTaskContext *ctx, void *tls, int poly_index)
 {
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
   const MPoly *coarse_poly = &coarse_mpoly[poly_index];
   if (coarse_poly->totloop == 4) {
     subdiv_foreach_loops_regular(ctx, tls, coarse_poly);
@@ -1676,7 +1680,7 @@ static void subdiv_foreach_polys(SubdivForeachTaskContext *ctx, void *tls, int p
   const int start_poly_index = ctx->subdiv_polygon_offset[poly_index];
   /* Base/coarse mesh information. */
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
   const MPoly *coarse_poly = &coarse_mpoly[poly_index];
   const int num_ptex_faces_per_poly = num_ptex_faces_per_poly_get(coarse_poly);
   const int ptex_resolution = ptex_face_resolution_get(coarse_poly, resolution);
@@ -1731,7 +1735,8 @@ static void subdiv_foreach_vertices_of_loose_edges_task(void *__restrict userdat
   const float inv_resolution_1 = 1.0f / (float)resolution_1;
   const int num_subdiv_vertices_per_coarse_edge = resolution - 2;
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MEdge *coarse_edge = &coarse_mesh->medge[coarse_edge_index];
+  const MEdge *coarse_edges = BKE_mesh_edges(coarse_mesh);
+  const MEdge *coarse_edge = &coarse_edges[coarse_edge_index];
   /* Subdivision vertices which corresponds to edge's v1 and v2. */
   const int subdiv_v1_index = ctx->vertices_corner_offset + coarse_edge->v1;
   const int subdiv_v2_index = ctx->vertices_corner_offset + coarse_edge->v2;
@@ -1768,7 +1773,7 @@ static void subdiv_foreach_single_geometry_vertices(SubdivForeachTaskContext *ct
     return;
   }
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
   for (int poly_index = 0; poly_index < coarse_mesh->totpoly; poly_index++) {
     const MPoly *coarse_poly = &coarse_mpoly[poly_index];
     subdiv_foreach_corner_vertices(ctx, tls, coarse_poly);
@@ -1779,8 +1784,8 @@ static void subdiv_foreach_single_geometry_vertices(SubdivForeachTaskContext *ct
 static void subdiv_foreach_mark_non_loose_geometry(SubdivForeachTaskContext *ctx)
 {
   const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
-  const MLoop *coarse_mloop = coarse_mesh->mloop;
+  const MPoly *coarse_mpoly = BKE_mesh_polys(coarse_mesh);
+  const MLoop *coarse_mloop = BKE_mesh_loops(coarse_mesh);
   for (int poly_index = 0; poly_index < coarse_mesh->totpoly; poly_index++) {
     const MPoly *coarse_poly = &coarse_mpoly[poly_index];
     for (int corner = 0; corner < coarse_poly->totloop; corner++) {
diff --git a/source/blender/blenkernel/intern/subdiv_mesh.c b/source/blender/blenkernel/intern/subdiv_mesh.c
deleted file mode 100644
index 433bad34479..00000000000
--- a/source/blender/blenkernel/intern/subdiv_mesh.c
+++ /dev/null
@@ -1,1201 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later
- * Copyright 2018 Blender Foundation. All rights reserved. */
-
-/** \file
- * \ingroup bke
- */
-
-#include "atomic_ops.h"
-
-#include "DNA_key_types.h"
-#include "DNA_mesh_types.h"
-#include "DNA_meshdata_types.h"
-
-#include "BLI_alloca.h"
-#include "BLI_bitmap.h"
-#include "BLI_math_vector.h"
-
-#include "BKE_customdata.h"
-#include "BKE_key.h"
-#include "BKE_mesh.h"
-#include "BKE_subdiv.h"
-#include "BKE_subdiv_eval.h"
-#include "BKE_subdiv_foreach.h"
-#include "BKE_subdiv_mesh.h"
-
-#include "MEM_guardedalloc.h"
-
-/* -------------------------------------------------------------------- */
-/** \name Subdivision Context
- * \{ */
-
-typedef struct SubdivMeshContext {
-  const SubdivToMeshSettings *settings;
-  const Mesh *coarse_mesh;
-  Subdiv *subdiv;
-  Mesh *subdiv_mesh;
-  /* Cached custom data arrays for faster access. */
-  int *vert_origindex;
-  int *edge_origindex;
-  int *loop_origindex;
-  int *poly_origindex;
-  /* UV layers interpolation. */
-  int num_uv_layers;
-  MLoopUV *uv_layers[MAX_MTFACE];
-  /* Original coordinates (ORCO) interpolation. */
-  float (*orco)[3];
-  float (*cloth_orco)[3];
-  /* Per-subdivided vertex counter of averaged values. */
-  int *accumulated_counters;
-  bool have_displacement;
-} SubdivMeshContext;
-
-static void subdiv_mesh_ctx_cache_uv_layers(SubdivMeshContext *ctx)
-{
-  Mesh *subdiv_mesh = ctx->subdiv_mesh;
-  ctx->num_uv_layers = CustomData_number_of_layers(&subdiv_mesh->ldata, CD_MLOOPUV);
-  for (int layer_index = 0; layer_index < ctx->num_uv_layers; layer_index++) {
-    ctx->uv_layers[layer_index] = CustomData_get_layer_n(
-        &subdiv_mesh->ldata, CD_MLOOPUV, layer_index);
-  }
-}
-
-static void subdiv_mesh_ctx_cache_custom_data_layers(SubdivMeshContext *ctx)
-{
-  Mesh *subdiv_mesh = ctx->subdiv_mesh;
-  /* Pointers to original indices layers. */
-  ctx->vert_origindex = CustomData_get_layer(&subdiv_mesh->vdata, CD_ORIGINDEX);
-  ctx->edge_origindex = CustomData_get_layer(&subdiv_mesh->edata, CD_ORIGINDEX);
-  ctx->loop_origindex = CustomData_get_layer(&subdiv_mesh->ldata, CD_ORIGINDEX);
-  ctx->poly_origindex = CustomData_get_layer(&subdiv_mesh->pdata, CD_ORIGINDEX);
-  /* UV layers interpolation. */
-  subdiv_mesh_ctx_cache_uv_layers(ctx);
-  /* Orco interpolation. */
-  ctx->orco = CustomData_get_layer(&subdiv_mesh->vdata, CD_ORCO);
-  ctx->cloth_orco = CustomData_get_layer(&subdiv_mesh->vdata, CD_CLOTH_ORCO);
-}
-
-static void subdiv_mesh_prepare_accumulator(SubdivMeshContext *ctx, int num_vertices)
-{
-  if (!ctx->have_displacement) {
-    return;
-  }
-  ctx->accumulated_counters = MEM_calloc_arrayN(
-      num_vertices, sizeof(*ctx->accumulated_counters), "subdiv accumulated counters");
-}
-
-static void subdiv_mesh_context_free(SubdivMeshContext *ctx)
-{
-  MEM_SAFE_FREE(ctx->accumulated_counters);
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Loop custom data copy helpers
- * \{ */
-
-typedef struct LoopsOfPtex {
-  /* First loop of the ptex, starts at ptex (0, 0) and goes in u direction. */
-  const MLoop *first_loop;
-  /* Last loop of the ptex, starts at ptex (0, 0) and goes in v direction. */
-  const MLoop *last_loop;
-  /* For quad coarse faces only. */
-  const MLoop *second_loop;
-  const MLoop *third_loop;
-} LoopsOfPtex;
-
-static void loops_of_ptex_get(const SubdivMeshContext *ctx,
-                              LoopsOfPtex *loops_of_ptex,
-                              const MPoly *coarse_poly,
-                              const int ptex_of_poly_index)
-{
-  const MLoop *coarse_mloop = ctx->coarse_mesh->mloop;
-  const int first_ptex_loop_index = coarse_poly->loopstart + ptex_of_poly_index;
-  /* Loop which look in the (opposite) V direction of the current
-   * ptex face.
-   *
-   * TODO(sergey): Get rid of using module on every iteration. */
-  const int last_ptex_loop_index = coarse_poly->loopstart +
-                                   (ptex_of_poly_index + coarse_poly->totloop - 1) %
-                                       coarse_poly->totloop;
-  loops_of_ptex->first_loop = &coarse_mloop[first_ptex_loop_index];
-  loops_of_ptex->last_loop = &coarse_mloop[last_ptex_loop_index];
-  if (coarse_poly->totloop == 4) {
-    loops_of_ptex->second_loop = loops_of_ptex->first_loop + 1;
-    loops_of_ptex->third_loop = loops_of_ptex->first_loop + 2;
-  }
-  else {
-    loops_of_ptex->second_loop = NULL;
-    loops_of_ptex->third_loop = NULL;
-  }
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Vertex custom data interpolation helpers
- * \{ */
-
-/* TODO(sergey): Somehow de-duplicate with loops storage, without too much
- * exception cases all over the code. */
-
-typedef struct VerticesForInterpolation {
-  /* This field points to a vertex data which is to be used for interpolation.
-   * The idea is to avoid unnecessary allocations for regular faces, where
-   * we can simply use corner vertices. */
-  const CustomData *vertex_data;
-  /* Vertices data calculated for ptex corners. There are always 4 elements
-   * in this custom data, aligned the following way:
-   *
-   *   index 0 -> uv (0, 0)
-   *   index 1 -> uv (0, 1)
-   *   index 2 -> uv (1, 1)
-   *   index 3 -> uv (1, 0)
-   *
-   * Is allocated for non-regular faces (triangles and n-gons). */
-  CustomData vertex_data_storage;
-  bool vertex_data_storage_allocated;
-  /* Indices within vertex_data to interpolate for. The indices are aligned
-   * with uv coordinates in a similar way as indices in loop_data_storage. */
-  int vertex_indices[4];
-} VerticesForInterpolation;
-
-static void vertex_interpolation_init(const SubdivMeshContext *ctx,
-                                      VerticesForInterpolation *vertex_interpolation,
-                                      const MPoly *coarse_poly)
-{
-  const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MLoop *coarse_mloop = coarse_mesh->mloop;
-  if (coarse_poly->totloop == 4) {
-    vertex_interpolation->vertex_data = &coarse_mesh->vdata;
-    vertex_interpolation->vertex_indices[0] = coarse_mloop[coarse_poly->loopstart + 0].v;
-    vertex_interpolation->vertex_indices[1] = coarse_mloop[coarse_poly->loopstart + 1].v;
-    vertex_interpolation->vertex_indices[2] = coarse_mloop[coarse_poly->loopstart + 2].v;
-    vertex_interpolation->vertex_indices[3] = coarse_mloop[coarse_poly->loopstart + 3].v;
-    vertex_interpolation->vertex_data_storage_allocated = false;
-  }
-  else {
-    vertex_interpolation->vertex_data = &vertex_interpolation->vertex_data_storage;
-    /* Allocate storage for loops corresponding to ptex corners. */
-    CustomData_copy(&ctx->coarse_mesh->vdata,
-                    &vertex_interpolation->vertex_data_storage,
-                    CD_MASK_EVERYTHING.vmask,
-                    CD_CALLOC,
-                    4);
-    /* Initialize indices. */
-    vertex_interpolation->vertex_indices[0] = 0;
-    vertex_interpolation->vertex_indices[1] = 1;
-    vertex_interpolation->vertex_indices[2] = 2;
-    vertex_interpolation->vertex_indices[3] = 3;
-    vertex_interpolation->vertex_data_storage_allocated = true;
-    /* Interpolate center of poly right away, it stays unchanged for all
-     * ptex faces. */
-    const float weight = 1.0f / (float)coarse_poly->totloop;
-    float *weights = BLI_array_alloca(weights, coarse_poly->totloop);
-    int *indices = BLI_array_alloca(indices, coarse_poly->totloop);
-    for (int i = 0; i < coarse_poly->totloop; i++) {
-      weights[i] = weight;
-      indices[i] = coarse_mloop[coarse_poly->loopstart + i].v;
-    }
-    CustomData_interp(&coarse_mesh->vdata,
-                      &vertex_interpolation->vertex_data_storage,
-                      indices,
-                      weights,
-                      NULL,
-                      coarse_poly->totloop,
-                      2);
-  }
-}
-
-static void vertex_interpolation_from_corner(const SubdivMeshContext *ctx,
-                                             VerticesForInterpolation *vertex_interpolation,
-                                             const MPoly *coarse_poly,
-                                             const int corner)
-{
-  if (coarse_poly->totloop == 4) {
-    /* Nothing to do, all indices and data is already assigned. */
-  }
-  else {
-    const CustomData *vertex_data = &ctx->coarse_mesh->vdata;
-    const Mesh *coarse_mesh = ctx->coarse_mesh;
-    const MLoop *coarse_mloop = coarse_mesh->mloop;
-    LoopsOfPtex loops_of_ptex;
-    loops_of_ptex_get(ctx, &loops_of_ptex, coarse_poly, corner);
-    /* Ptex face corner corresponds to a poly loop with same index. */
-    CustomData_copy_data(vertex_data,
-                         &vertex_interpolation->vertex_data_storage,
-                         coarse_mloop[coarse_poly->loopstart + corner].v,
-                         0,
-                         1);
-    /* Interpolate remaining ptex face corners, which hits loops
-     * middle points.
-     *
-     * TODO(sergey): Re-use one of interpolation results from previous
-     * iteration. */
-    const float weights[2] = {0.5f, 0.5f};
-    const int first_loop_index = loops_of_ptex.first_loop - coarse_mloop;
-    const int last_loop_index = loops_of_ptex.last_loop - coarse_mloop;
-    const int first_indices[2] = {
-        coarse_mloop[first_loop_index].v,
-        coarse_mloop[coarse_poly->loopstart +
-                     (first_loop_index - coarse_poly->loopstart + 1) % coarse_poly->totloop]
-            .v};
-    const int last_indices[2] = {
-        coarse_mloop[first_loop_index].v,
-        coarse_mloop[last_loop_index].v,
-    };
-    CustomData_interp(vertex_data,
-                      &vertex_interpolation->vertex_data_storage,
-                      first_indices,
-                      weights,
-                      NULL,
-                      2,
-                      1);
-    CustomData_interp(vertex_data,
-                      &vertex_interpolation->vertex_data_storage,
-                      last_indices,
-                      weights,
-                      NULL,
-                      2,
-                      3);
-  }
-}
-
-static void vertex_interpolation_end(VerticesForInterpolation *vertex_interpolation)
-{
-  if (vertex_interpolation->vertex_data_storage_allocated) {
-    CustomData_free(&vertex_interpolation->vertex_data_storage, 4);
-  }
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Loop custom data interpolation helpers
- * \{ */
-
-typedef struct LoopsForInterpolation {
-  /* This field points to a loop data which is to be used for interpolation.
-   * The idea is to avoid unnecessary allocations for regular faces, where
-   * we can simply interpolate corner vertices. */
-  const CustomData *loop_data;
-  /* Loops data calculated for ptex corners. There are always 4 elements
-   * in this custom data, aligned the following way:
-   *
-   *   index 0 -> uv (0, 0)
-   *   index 1 -> uv (0, 1)
-   *   index 2 -> uv (1, 1)
-   *   index 3 -> uv (1, 0)
-   *
-   * Is allocated for non-regular faces (triangles and n-gons). */
-  CustomData loop_data_storage;
-  bool loop_data_storage_allocated;
-  /* Infices within loop_data to interpolate for. The indices are aligned with
-   * uv coordinates in a similar way as indices in loop_data_storage. */
-  int loop_indices[4];
-} LoopsForInterpolation;
-
-static void loop_interpolation_init(const SubdivMeshContext *ctx,
-                                    LoopsForInterpolation *loop_interpolation,
-                                    const MPoly *coarse_poly)
-{
-  const Mesh *coarse_mesh = ctx->coarse_mesh;
-  if (coarse_poly->totloop == 4) {
-    loop_interpolation->loop_data = &coarse_mesh->ldata;
-    loop_interpolation->loop_indices[0] = coarse_poly->loopstart + 0;
-    loop_interpolation->loop_indices[1] = coarse_poly->loopstart + 1;
-    loop_interpolation->loop_indices[2] = coarse_poly->loopstart + 2;
-    loop_interpolation->loop_indices[3] = coarse_poly->loopstart + 3;
-    loop_interpolation->loop_data_storage_allocated = false;
-  }
-  else {
-    loop_interpolation->loop_data = &loop_interpolation->loop_data_storage;
-    /* Allocate storage for loops corresponding to ptex corners. */
-    CustomData_copy(&ctx->coarse_mesh->ldata,
-                    &loop_interpolation->loop_data_storage,
-                    CD_MASK_EVERYTHING.lmask,
-                    CD_CALLOC,
-                    4);
-    /* Initialize indices. */
-    loop_interpolation->loop_indices[0] = 0;
-    loop_interpolation->loop_indices[1] = 1;
-    loop_interpolation->loop_indices[2] = 2;
-    loop_interpolation->loop_indices[3] = 3;
-    loop_interpolation->loop_data_storage_allocated = true;
-    /* Interpolate center of poly right away, it stays unchanged for all
-     * ptex faces. */
-    const float weight = 1.0f / (float)coarse_poly->totloop;
-    float *weights = BLI_array_alloca(weights, coarse_poly->totloop);
-    int *indices = BLI_array_alloca(indices, coarse_poly->totloop);
-    for (int i = 0; i < coarse_poly->totloop; i++) {
-      weights[i] = weight;
-      indices[i] = coarse_poly->loopstart + i;
-    }
-    CustomData_interp(&coarse_mesh->ldata,
-                      &loop_interpolation->loop_data_storage,
-                      indices,
-                      weights,
-                      NULL,
-                      coarse_poly->totloop,
-                      2);
-  }
-}
-
-static void loop_interpolation_from_corner(const SubdivMeshContext *ctx,
-                                           LoopsForInterpolation *loop_interpolation,
-                                           const MPoly *coarse_poly,
-                                           const int corner)
-{
-  if (coarse_poly->totloop == 4) {
-    /* Nothing to do, all indices and data is already assigned. */
-  }
-  else {
-    const CustomData *loop_data = &ctx->coarse_mesh->ldata;
-    const Mesh *coarse_mesh = ctx->coarse_mesh;
-    const MLoop *coarse_mloop = coarse_mesh->mloop;
-    LoopsOfPtex loops_of_ptex;
-    loops_of_ptex_get(ctx, &loops_of_ptex, coarse_poly, corner);
-    /* Ptex face corner corresponds to a poly loop with same index. */
-    CustomData_free_elem(&loop_interpolation->loop_data_storage, 0, 1);
-    CustomData_copy_data(
-        loop_data, &loop_interpolation->loop_data_storage, coarse_poly->loopstart + corner, 0, 1);
-    /* Interpolate remaining ptex face corners, which hits loops
-     * middle points.
-     *
-     * TODO(sergey): Re-use one of interpolation results from previous
-     * iteration. */
-    const float weights[2] = {0.5f, 0.5f};
-    const int base_loop_index = coarse_poly->loopstart;
-    const int first_loop_index = loops_of_ptex.first_loop - coarse_mloop;
-    const int second_loop_index = base_loop_index +
-                                  (first_loop_index - base_loop_index + 1) % coarse_poly->totloop;
-    const int first_indices[2] = {first_loop_index, second_loop_index};
-    const int last_indices[2] = {
-        loops_of_ptex.last_loop - coarse_mloop,
-        loops_of_ptex.first_loop - coarse_mloop,
-    };
-    CustomData_interp(
-        loop_data, &loop_interpolation->loop_data_storage, first_indices, weights, NULL, 2, 1);
-    CustomData_interp(
-        loop_data, &loop_interpolation->loop_data_storage, last_indices, weights, NULL, 2, 3);
-  }
-}
-
-static void loop_interpolation_end(LoopsForInterpolation *loop_interpolation)
-{
-  if (loop_interpolation->loop_data_storage_allocated) {
-    CustomData_free(&loop_interpolation->loop_data_storage, 4);
-  }
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name TLS
- * \{ */
-
-typedef struct SubdivMeshTLS {
-  bool vertex_interpolation_initialized;
-  VerticesForInterpolation vertex_interpolation;
-  const MPoly *vertex_interpolation_coarse_poly;
-  int vertex_interpolation_coarse_corner;
-
-  bool loop_interpolation_initialized;
-  LoopsForInterpolation loop_interpolation;
-  const MPoly *loop_interpolation_coarse_poly;
-  int loop_interpolation_coarse_corner;
-} SubdivMeshTLS;
-
-static void subdiv_mesh_tls_free(void *tls_v)
-{
-  SubdivMeshTLS *tls = tls_v;
-  if (tls->vertex_interpolation_initialized) {
-    vertex_interpolation_end(&tls->vertex_interpolation);
-  }
-  if (tls->loop_interpolation_initialized) {
-    loop_interpolation_end(&tls->loop_interpolation);
-  }
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Evaluation helper functions
- * \{ */
-
-static void subdiv_vertex_orco_evaluate(const SubdivMeshContext *ctx,
-                                        const int ptex_face_index,
-                                        const float u,
-                                        const float v,
-                                        const int subdiv_vertex_index)
-{
-  if (ctx->orco || ctx->cloth_orco) {
-    float vertex_data[6];
-    BKE_subdiv_eval_vertex_data(ctx->subdiv, ptex_face_index, u, v, vertex_data);
-
-    if (ctx->orco) {
-      copy_v3_v3(ctx->orco[subdiv_vertex_index], vertex_data);
-      if (ctx->cloth_orco) {
-        copy_v3_v3(ctx->orco[subdiv_vertex_index], vertex_data + 3);
-      }
-    }
-    else if (ctx->cloth_orco) {
-      copy_v3_v3(ctx->orco[subdiv_vertex_index], vertex_data);
-    }
-  }
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Accumulation helpers
- * \{ */
-
-static void subdiv_accumulate_vertex_displacement(SubdivMeshContext *ctx,
-                                                  const int ptex_face_index,
-                                                  const float u,
-                                                  const float v,
-                                                  MVert *subdiv_vert)
-{
-  /* Accumulate displacement. */
-  Subdiv *subdiv = ctx->subdiv;
-  const int subdiv_vertex_index = subdiv_vert - ctx->subdiv_mesh->mvert;
-  float dummy_P[3], dPdu[3], dPdv[3], D[3];
-  BKE_subdiv_eval_limit_point_and_derivatives(subdiv, ptex_face_index, u, v, dummy_P, dPdu, dPdv);
-
-  /* NOTE: The subdivided mesh is allocated in this module, and its vertices are kept at zero
-   * locations as a default calloc(). */
-  BKE_subdiv_eval_displacement(subdiv, ptex_face_index, u, v, dPdu, dPdv, D);
-  add_v3_v3(subdiv_vert->co, D);
-
-  if (ctx->accumulated_counters) {
-    ++ctx->accumulated_counters[subdiv_vertex_index];
-  }
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Callbacks
- * \{ */
-
-static bool subdiv_mesh_topology_info(const SubdivForeachContext *foreach_context,
-                                      const int num_vertices,
-                                      const int num_edges,
-                                      const int num_loops,
-                                      const int num_polygons,
-                                      const int *UNUSED(subdiv_polygon_offset))
-{
-  /* Multi-resolution grid data will be applied or become invalid after subdivision,
-   * so don't try to preserve it and use memory. */
-  CustomData_MeshMasks mask = CD_MASK_EVERYTHING;
-  mask.lmask &= ~CD_MASK_MULTIRES_GRIDS;
-
-  SubdivMeshContext *subdiv_context = foreach_context->user_data;
-  subdiv_context->subdiv_mesh = BKE_mesh_new_nomain_from_template_ex(
-      subdiv_context->coarse_mesh, num_vertices, num_edges, 0, num_loops, num_polygons, mask);
-  subdiv_mesh_ctx_cache_custom_data_layers(subdiv_context);
-  subdiv_mesh_prepare_accumulator(subdiv_context, num_vertices);
-  MEM_SAFE_FREE(subdiv_context->subdiv_mesh->runtime.subsurf_face_dot_tags);
-  subdiv_context->subdiv_mesh->runtime.subsurf_face_dot_tags = BLI_BITMAP_NEW(num_vertices,
-                                                                              __func__);
-  return true;
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Vertex subdivision process
- * \{ */
-
-static void subdiv_vertex_data_copy(const SubdivMeshContext *ctx,
-                                    const MVert *coarse_vertex,
-                                    MVert *subdiv_vertex)
-{
-  const Mesh *coarse_mesh = ctx->coarse_mesh;
-  Mesh *subdiv_mesh = ctx->subdiv_mesh;
-  const int coarse_vertex_index = coarse_vertex - coarse_mesh->mvert;
-  const int subdiv_vertex_index = subdiv_vertex - subdiv_mesh->mvert;
-  CustomData_copy_data(
-      &coarse_mesh->vdata, &ctx->subdiv_mesh->vdata, coarse_vertex_index, subdiv_vertex_index, 1);
-}
-
-static void subdiv_vertex_data_interpolate(const SubdivMeshContext *ctx,
-                                           MVert *subdiv_vertex,
-                                           const VerticesForInterpolation *vertex_interpolation,
-                                           const float u,
-                                           const float v)
-{
-  const int subdiv_vertex_index = subdiv_vertex - ctx->subdiv_mesh->mvert;
-  const float weights[4] = {(1.0f - u) * (1.0f - v), u * (1.0f - v), u * v, (1.0f - u) * v};
-  CustomData_interp(vertex_interpolation->vertex_data,
-                    &ctx->subdiv_mesh->vdata,
-                    vertex_interpolation->vertex_indices,
-                    weights,
-                    NULL,
-                    4,
-                    subdiv_vertex_index);
-  if (ctx->vert_origindex != NULL) {
-    ctx->vert_origindex[subdiv_vertex_index] = ORIGINDEX_NONE;
-  }
-}
-
-static void evaluate_vertex_and_apply_displacement_copy(const SubdivMeshContext *ctx,
-                                                        const int ptex_face_index,
-                                                        const float u,
-                                                        const float v,
-                                                        const MVert *coarse_vert,
-                                                        MVert *subdiv_vert)
-{
-  const int subdiv_vertex_index = subdiv_vert - ctx->subdiv_mesh->mvert;
-  /* Displacement is accumulated in subdiv vertex position.
-   * Needs to be backed up before copying data from original vertex. */
-  float D[3] = {0.0f, 0.0f, 0.0f};
-  if (ctx->have_displacement) {
-    const float inv_num_accumulated = 1.0f / ctx->accumulated_counters[subdiv_vertex_index];
-    copy_v3_v3(D, subdiv_vert->co);
-    mul_v3_fl(D, inv_num_accumulated);
-  }
-  /* Copy custom data and evaluate position. */
-  subdiv_vertex_data_copy(ctx, coarse_vert, subdiv_vert);
-  BKE_subdiv_eval_limit_point(ctx->subdiv, ptex_face_index, u, v, subdiv_vert->co);
-  /* Apply displacement. */
-  add_v3_v3(subdiv_vert->co, D);
-  /* Evaluate undeformed texture coordinate. */
-  subdiv_vertex_orco_evaluate(ctx, ptex_face_index, u, v, subdiv_vertex_index);
-  /* Remove facedot flag. This can happen if there is more than one subsurf modifier. */
-  BLI_BITMAP_DISABLE(ctx->subdiv_mesh->runtime.subsurf_face_dot_tags, subdiv_vertex_index);
-}
-
-static void evaluate_vertex_and_apply_displacement_interpolate(
-    const SubdivMeshContext *ctx,
-    const int ptex_face_index,
-    const float u,
-    const float v,
-    VerticesForInterpolation *vertex_interpolation,
-    MVert *subdiv_vert)
-{
-  const int subdiv_vertex_index = subdiv_vert - ctx->subdiv_mesh->mvert;
-  /* Displacement is accumulated in subdiv vertex position.
-   * Needs to be backed up before copying data from original vertex. */
-  float D[3] = {0.0f, 0.0f, 0.0f};
-  if (ctx->have_displacement) {
-    const float inv_num_accumulated = 1.0f / ctx->accumulated_counters[subdiv_vertex_index];
-    copy_v3_v3(D, subdiv_vert->co);
-    mul_v3_fl(D, inv_num_accumulated);
-  }
-  /* Interpolate custom data and evaluate position. */
-  subdiv_vertex_data_interpolate(ctx, subdiv_vert, vertex_interpolation, u, v);
-  BKE_subdiv_eval_limit_point(ctx->subdiv, ptex_face_index, u, v, subdiv_vert->co);
-  /* Apply displacement. */
-  add_v3_v3(subdiv_vert->co, D);
-  /* Evaluate undeformed texture coordinate. */
-  subdiv_vertex_orco_evaluate(ctx, ptex_face_index, u, v, subdiv_vertex_index);
-}
-
-static void subdiv_mesh_vertex_displacement_every_corner_or_edge(
-    const SubdivForeachContext *foreach_context,
-    void *UNUSED(tls),
-    const int ptex_face_index,
-    const float u,
-    const float v,
-    const int subdiv_vertex_index)
-{
-  SubdivMeshContext *ctx = foreach_context->user_data;
-  Mesh *subdiv_mesh = ctx->subdiv_mesh;
-  MVert *subdiv_mvert = subdiv_mesh->mvert;
-  MVert *subdiv_vert = &subdiv_mvert[subdiv_vertex_index];
-  subdiv_accumulate_vertex_displacement(ctx, ptex_face_index, u, v, subdiv_vert);
-}
-
-static void subdiv_mesh_vertex_displacement_every_corner(
-    const SubdivForeachContext *foreach_context,
-    void *tls,
-    const int ptex_face_index,
-    const float u,
-    const float v,
-    const int UNUSED(coarse_vertex_index),
-    const int UNUSED(coarse_poly_index),
-    const int UNUSED(coarse_corner),
-    const int subdiv_vertex_index)
-{
-  subdiv_mesh_vertex_displacement_every_corner_or_edge(
-      foreach_context, tls, ptex_face_index, u, v, subdiv_vertex_index);
-}
-
-static void subdiv_mesh_vertex_displacement_every_edge(const SubdivForeachContext *foreach_context,
-                                                       void *tls,
-                                                       const int ptex_face_index,
-                                                       const float u,
-                                                       const float v,
-                                                       const int UNUSED(coarse_edge_index),
-                                                       const int UNUSED(coarse_poly_index),
-                                                       const int UNUSED(coarse_corner),
-                                                       const int subdiv_vertex_index)
-{
-  subdiv_mesh_vertex_displacement_every_corner_or_edge(
-      foreach_context, tls, ptex_face_index, u, v, subdiv_vertex_index);
-}
-
-static void subdiv_mesh_vertex_corner(const SubdivForeachContext *foreach_context,
-                                      void *UNUSED(tls),
-                                      const int ptex_face_index,
-                                      const float u,
-                                      const float v,
-                                      const int coarse_vertex_index,
-                                      const int UNUSED(coarse_poly_index),
-                                      const int UNUSED(coarse_corner),
-                                      const int subdiv_vertex_index)
-{
-  BLI_assert(coarse_vertex_index != ORIGINDEX_NONE);
-  SubdivMeshContext *ctx = foreach_context->user_data;
-  const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MVert *coarse_mvert = coarse_mesh->mvert;
-  Mesh *subdiv_mesh = ctx->subdiv_mesh;
-  MVert *subdiv_mvert = subdiv_mesh->mvert;
-  const MVert *coarse_vert = &coarse_mvert[coarse_vertex_index];
-  MVert *subdiv_vert = &subdiv_mvert[subdiv_vertex_index];
-  evaluate_vertex_and_apply_displacement_copy(
-      ctx, ptex_face_index, u, v, coarse_vert, subdiv_vert);
-}
-
-static void subdiv_mesh_ensure_vertex_interpolation(SubdivMeshContext *ctx,
-                                                    SubdivMeshTLS *tls,
-                                                    const MPoly *coarse_poly,
-                                                    const int coarse_corner)
-{
-  /* Check whether we've moved to another corner or polygon. */
-  if (tls->vertex_interpolation_initialized) {
-    if (tls->vertex_interpolation_coarse_poly != coarse_poly ||
-        tls->vertex_interpolation_coarse_corner != coarse_corner) {
-      vertex_interpolation_end(&tls->vertex_interpolation);
-      tls->vertex_interpolation_initialized = false;
-    }
-  }
-  /* Initialize the interpolation. */
-  if (!tls->vertex_interpolation_initialized) {
-    vertex_interpolation_init(ctx, &tls->vertex_interpolation, coarse_poly);
-  }
-  /* Update it for a new corner if needed. */
-  if (!tls->vertex_interpolation_initialized ||
-      tls->vertex_interpolation_coarse_corner != coarse_corner) {
-    vertex_interpolation_from_corner(ctx, &tls->vertex_interpolation, coarse_poly, coarse_corner);
-  }
-  /* Store settings used for the current state of interpolator. */
-  tls->vertex_interpolation_initialized = true;
-  tls->vertex_interpolation_coarse_poly = coarse_poly;
-  tls->vertex_interpolation_coarse_corner = coarse_corner;
-}
-
-static void subdiv_mesh_vertex_edge(const SubdivForeachContext *foreach_context,
-                                    void *tls_v,
-                                    const int ptex_face_index,
-                                    const float u,
-                                    const float v,
-                                    const int UNUSED(coarse_edge_index),
-                                    const int coarse_poly_index,
-                                    const int coarse_corner,
-                                    const int subdiv_vertex_index)
-{
-  SubdivMeshContext *ctx = foreach_context->user_data;
-  SubdivMeshTLS *tls = tls_v;
-  const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
-  const MPoly *coarse_poly = &coarse_mpoly[coarse_poly_index];
-  Mesh *subdiv_mesh = ctx->subdiv_mesh;
-  MVert *subdiv_mvert = subdiv_mesh->mvert;
-  MVert *subdiv_vert = &subdiv_mvert[subdiv_vertex_index];
-  subdiv_mesh_ensure_vertex_interpolation(ctx, tls, coarse_poly, coarse_corner);
-  evaluate_vertex_and_apply_displacement_interpolate(
-      ctx, ptex_face_index, u, v, &tls->vertex_interpolation, subdiv_vert);
-}
-
-static bool subdiv_mesh_is_center_vertex(const MPoly *coarse_poly, const float u, const float v)
-{
-  if (coarse_poly->totloop == 4) {
-    if (u == 0.5f && v == 0.5f) {
-      return true;
-    }
-  }
-  else {
-    if (u == 1.0f && v == 1.0f) {
-      return true;
-    }
-  }
-  return false;
-}
-
-static void subdiv_mesh_tag_center_vertex(const MPoly *coarse_poly,
-                                          const int subdiv_vertex_index,
-                                          const float u,
-                                          const float v,
-                                          Mesh *subdiv_mesh)
-{
-  if (subdiv_mesh_is_center_vertex(coarse_poly, u, v)) {
-    BLI_BITMAP_ENABLE(subdiv_mesh->runtime.subsurf_face_dot_tags, subdiv_vertex_index);
-  }
-}
-
-static void subdiv_mesh_vertex_inner(const SubdivForeachContext *foreach_context,
-                                     void *tls_v,
-                                     const int ptex_face_index,
-                                     const float u,
-                                     const float v,
-                                     const int coarse_poly_index,
-                                     const int coarse_corner,
-                                     const int subdiv_vertex_index)
-{
-  SubdivMeshContext *ctx = foreach_context->user_data;
-  SubdivMeshTLS *tls = tls_v;
-  Subdiv *subdiv = ctx->subdiv;
-  const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
-  const MPoly *coarse_poly = &coarse_mpoly[coarse_poly_index];
-  Mesh *subdiv_mesh = ctx->subdiv_mesh;
-  MVert *subdiv_mvert = subdiv_mesh->mvert;
-  MVert *subdiv_vert = &subdiv_mvert[subdiv_vertex_index];
-  subdiv_mesh_ensure_vertex_interpolation(ctx, tls, coarse_poly, coarse_corner);
-  subdiv_vertex_data_interpolate(ctx, subdiv_vert, &tls->vertex_interpolation, u, v);
-  BKE_subdiv_eval_final_point(subdiv, ptex_face_index, u, v, subdiv_vert->co);
-  subdiv_mesh_tag_center_vertex(coarse_poly, subdiv_vertex_index, u, v, subdiv_mesh);
-  subdiv_vertex_orco_evaluate(ctx, ptex_face_index, u, v, subdiv_vertex_index);
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Edge subdivision process
- * \{ */
-
-static void subdiv_copy_edge_data(SubdivMeshContext *ctx,
-                                  MEdge *subdiv_edge,
-                                  const MEdge *coarse_edge)
-{
-  const int subdiv_edge_index = subdiv_edge - ctx->subdiv_mesh->medge;
-  if (coarse_edge == NULL) {
-    subdiv_edge->crease = 0;
-    subdiv_edge->bweight = 0;
-    subdiv_edge->flag = 0;
-    if (!ctx->settings->use_optimal_display) {
-      subdiv_edge->flag |= ME_EDGERENDER;
-    }
-    if (ctx->edge_origindex != NULL) {
-      ctx->edge_origindex[subdiv_edge_index] = ORIGINDEX_NONE;
-    }
-    return;
-  }
-  const int coarse_edge_index = coarse_edge - ctx->coarse_mesh->medge;
-  CustomData_copy_data(
-      &ctx->coarse_mesh->edata, &ctx->subdiv_mesh->edata, coarse_edge_index, subdiv_edge_index, 1);
-  subdiv_edge->flag |= ME_EDGERENDER;
-}
-
-static void subdiv_mesh_edge(const SubdivForeachContext *foreach_context,
-                             void *UNUSED(tls),
-                             const int coarse_edge_index,
-                             const int subdiv_edge_index,
-                             const bool UNUSED(is_loose),
-                             const int subdiv_v1,
-                             const int subdiv_v2)
-{
-  SubdivMeshContext *ctx = foreach_context->user_data;
-  Mesh *subdiv_mesh = ctx->subdiv_mesh;
-  MEdge *subdiv_medge = subdiv_mesh->medge;
-  MEdge *subdiv_edge = &subdiv_medge[subdiv_edge_index];
-  const MEdge *coarse_edge = NULL;
-  if (coarse_edge_index != ORIGINDEX_NONE) {
-    const Mesh *coarse_mesh = ctx->coarse_mesh;
-    const MEdge *coarse_medge = coarse_mesh->medge;
-    coarse_edge = &coarse_medge[coarse_edge_index];
-  }
-  subdiv_copy_edge_data(ctx, subdiv_edge, coarse_edge);
-  subdiv_edge->v1 = subdiv_v1;
-  subdiv_edge->v2 = subdiv_v2;
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Loops creation/interpolation
- * \{ */
-
-static void subdiv_interpolate_loop_data(const SubdivMeshContext *ctx,
-                                         MLoop *subdiv_loop,
-                                         const LoopsForInterpolation *loop_interpolation,
-                                         const float u,
-                                         const float v)
-{
-  const int subdiv_loop_index = subdiv_loop - ctx->subdiv_mesh->mloop;
-  const float weights[4] = {(1.0f - u) * (1.0f - v), u * (1.0f - v), u * v, (1.0f - u) * v};
-  CustomData_interp(loop_interpolation->loop_data,
-                    &ctx->subdiv_mesh->ldata,
-                    loop_interpolation->loop_indices,
-                    weights,
-                    NULL,
-                    4,
-                    subdiv_loop_index);
-  /* TODO(sergey): Set ORIGINDEX. */
-}
-
-static void subdiv_eval_uv_layer(SubdivMeshContext *ctx,
-                                 MLoop *subdiv_loop,
-                                 const int ptex_face_index,
-                                 const float u,
-                                 const float v)
-{
-  if (ctx->num_uv_layers == 0) {
-    return;
-  }
-  Subdiv *subdiv = ctx->subdiv;
-  const int mloop_index = subdiv_loop - ctx->subdiv_mesh->mloop;
-  for (int layer_index = 0; layer_index < ctx->num_uv_layers; layer_index++) {
-    MLoopUV *subdiv_loopuv = &ctx->uv_layers[layer_index][mloop_index];
-    BKE_subdiv_eval_face_varying(subdiv, layer_index, ptex_face_index, u, v, subdiv_loopuv->uv);
-  }
-}
-
-static void subdiv_mesh_ensure_loop_interpolation(SubdivMeshContext *ctx,
-                                                  SubdivMeshTLS *tls,
-                                                  const MPoly *coarse_poly,
-                                                  const int coarse_corner)
-{
-  /* Check whether we've moved to another corner or polygon. */
-  if (tls->loop_interpolation_initialized) {
-    if (tls->loop_interpolation_coarse_poly != coarse_poly ||
-        tls->loop_interpolation_coarse_corner != coarse_corner) {
-      loop_interpolation_end(&tls->loop_interpolation);
-      tls->loop_interpolation_initialized = false;
-    }
-  }
-  /* Initialize the interpolation. */
-  if (!tls->loop_interpolation_initialized) {
-    loop_interpolation_init(ctx, &tls->loop_interpolation, coarse_poly);
-  }
-  /* Update it for a new corner if needed. */
-  if (!tls->loop_interpolation_initialized ||
-      tls->loop_interpolation_coarse_corner != coarse_corner) {
-    loop_interpolation_from_corner(ctx, &tls->loop_interpolation, coarse_poly, coarse_corner);
-  }
-  /* Store settings used for the current state of interpolator. */
-  tls->loop_interpolation_initialized = true;
-  tls->loop_interpolation_coarse_poly = coarse_poly;
-  tls->loop_interpolation_coarse_corner = coarse_corner;
-}
-
-static void subdiv_mesh_loop(const SubdivForeachContext *foreach_context,
-                             void *tls_v,
-                             const int ptex_face_index,
-                             const float u,
-                             const float v,
-                             const int UNUSED(coarse_loop_index),
-                             const int coarse_poly_index,
-                             const int coarse_corner,
-                             const int subdiv_loop_index,
-                             const int subdiv_vertex_index,
-                             const int subdiv_edge_index)
-{
-  SubdivMeshContext *ctx = foreach_context->user_data;
-  SubdivMeshTLS *tls = tls_v;
-  const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
-  const MPoly *coarse_poly = &coarse_mpoly[coarse_poly_index];
-  Mesh *subdiv_mesh = ctx->subdiv_mesh;
-  MLoop *subdiv_mloop = subdiv_mesh->mloop;
-  MLoop *subdiv_loop = &subdiv_mloop[subdiv_loop_index];
-  subdiv_mesh_ensure_loop_interpolation(ctx, tls, coarse_poly, coarse_corner);
-  subdiv_interpolate_loop_data(ctx, subdiv_loop, &tls->loop_interpolation, u, v);
-  subdiv_eval_uv_layer(ctx, subdiv_loop, ptex_face_index, u, v);
-  subdiv_loop->v = subdiv_vertex_index;
-  subdiv_loop->e = subdiv_edge_index;
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Polygons subdivision process
- * \{ */
-
-static void subdiv_copy_poly_data(const SubdivMeshContext *ctx,
-                                  MPoly *subdiv_poly,
-                                  const MPoly *coarse_poly)
-{
-  const int coarse_poly_index = coarse_poly - ctx->coarse_mesh->mpoly;
-  const int subdiv_poly_index = subdiv_poly - ctx->subdiv_mesh->mpoly;
-  CustomData_copy_data(
-      &ctx->coarse_mesh->pdata, &ctx->subdiv_mesh->pdata, coarse_poly_index, subdiv_poly_index, 1);
-}
-
-static void subdiv_mesh_poly(const SubdivForeachContext *foreach_context,
-                             void *UNUSED(tls),
-                             const int coarse_poly_index,
-                             const int subdiv_poly_index,
-                             const int start_loop_index,
-                             const int num_loops)
-{
-  BLI_assert(coarse_poly_index != ORIGINDEX_NONE);
-  SubdivMeshContext *ctx = foreach_context->user_data;
-  const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MPoly *coarse_mpoly = coarse_mesh->mpoly;
-  const MPoly *coarse_poly = &coarse_mpoly[coarse_poly_index];
-  Mesh *subdiv_mesh = ctx->subdiv_mesh;
-  MPoly *subdiv_mpoly = subdiv_mesh->mpoly;
-  MPoly *subdiv_poly = &subdiv_mpoly[subdiv_poly_index];
-  subdiv_copy_poly_data(ctx, subdiv_poly, coarse_poly);
-  subdiv_poly->loopstart = start_loop_index;
-  subdiv_poly->totloop = num_loops;
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Loose elements subdivision process
- * \{ */
-
-static void subdiv_mesh_vertex_loose(const SubdivForeachContext *foreach_context,
-                                     void *UNUSED(tls),
-                                     const int coarse_vertex_index,
-                                     const int subdiv_vertex_index)
-{
-  SubdivMeshContext *ctx = foreach_context->user_data;
-  const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MVert *coarse_mvert = coarse_mesh->mvert;
-  const MVert *coarse_vertex = &coarse_mvert[coarse_vertex_index];
-  Mesh *subdiv_mesh = ctx->subdiv_mesh;
-  MVert *subdiv_mvert = subdiv_mesh->mvert;
-  MVert *subdiv_vertex = &subdiv_mvert[subdiv_vertex_index];
-  subdiv_vertex_data_copy(ctx, coarse_vertex, subdiv_vertex);
-}
-
-/* Get neighbor edges of the given one.
- * - neighbors[0] is an edge adjacent to edge->v1.
- * - neighbors[1] is an edge adjacent to edge->v2. */
-static void find_edge_neighbors(const Mesh *coarse_mesh,
-                                const MEdge *edge,
-                                const MEdge *neighbors[2])
-{
-  const MEdge *coarse_medge = coarse_mesh->medge;
-  neighbors[0] = NULL;
-  neighbors[1] = NULL;
-  int neighbor_counters[2] = {0, 0};
-  for (int edge_index = 0; edge_index < coarse_mesh->totedge; edge_index++) {
-    const MEdge *current_edge = &coarse_medge[edge_index];
-    if (current_edge == edge) {
-      continue;
-    }
-    if (ELEM(edge->v1, current_edge->v1, current_edge->v2)) {
-      neighbors[0] = current_edge;
-      ++neighbor_counters[0];
-    }
-    if (ELEM(edge->v2, current_edge->v1, current_edge->v2)) {
-      neighbors[1] = current_edge;
-      ++neighbor_counters[1];
-    }
-  }
-  /* Vertices which has more than one neighbor are considered infinitely
-   * sharp. This is also how topology factory treats vertices of a surface
-   * which are adjacent to a loose edge. */
-  if (neighbor_counters[0] > 1) {
-    neighbors[0] = NULL;
-  }
-  if (neighbor_counters[1] > 1) {
-    neighbors[1] = NULL;
-  }
-}
-
-static void points_for_loose_edges_interpolation_get(const Mesh *coarse_mesh,
-                                                     const MEdge *coarse_edge,
-                                                     const MEdge *neighbors[2],
-                                                     float points_r[4][3])
-{
-  const MVert *coarse_mvert = coarse_mesh->mvert;
-  /* Middle points corresponds to the edge. */
-  copy_v3_v3(points_r[1], coarse_mvert[coarse_edge->v1].co);
-  copy_v3_v3(points_r[2], coarse_mvert[coarse_edge->v2].co);
-  /* Start point, duplicate from edge start if no neighbor. */
-  if (neighbors[0] != NULL) {
-    if (neighbors[0]->v1 == coarse_edge->v1) {
-      copy_v3_v3(points_r[0], coarse_mvert[neighbors[0]->v2].co);
-    }
-    else {
-      copy_v3_v3(points_r[0], coarse_mvert[neighbors[0]->v1].co);
-    }
-  }
-  else {
-    sub_v3_v3v3(points_r[0], points_r[1], points_r[2]);
-    add_v3_v3(points_r[0], points_r[1]);
-  }
-  /* End point, duplicate from edge end if no neighbor. */
-  if (neighbors[1] != NULL) {
-    if (neighbors[1]->v1 == coarse_edge->v2) {
-      copy_v3_v3(points_r[3], coarse_mvert[neighbors[1]->v2].co);
-    }
-    else {
-      copy_v3_v3(points_r[3], coarse_mvert[neighbors[1]->v1].co);
-    }
-  }
-  else {
-    sub_v3_v3v3(points_r[3], points_r[2], points_r[1]);
-    add_v3_v3(points_r[3], points_r[2]);
-  }
-}
-
-void BKE_subdiv_mesh_interpolate_position_on_edge(const Mesh *coarse_mesh,
-                                                  const MEdge *coarse_edge,
-                                                  const bool is_simple,
-                                                  const float u,
-                                                  float pos_r[3])
-{
-  if (is_simple) {
-    const MVert *coarse_mvert = coarse_mesh->mvert;
-    const MVert *vert_1 = &coarse_mvert[coarse_edge->v1];
-    const MVert *vert_2 = &coarse_mvert[coarse_edge->v2];
-    interp_v3_v3v3(pos_r, vert_1->co, vert_2->co, u);
-  }
-  else {
-    /* Find neighbors of the coarse edge. */
-    const MEdge *neighbors[2];
-    find_edge_neighbors(coarse_mesh, coarse_edge, neighbors);
-    float points[4][3];
-    points_for_loose_edges_interpolation_get(coarse_mesh, coarse_edge, neighbors, points);
-    float weights[4];
-    key_curve_position_weights(u, weights, KEY_BSPLINE);
-    interp_v3_v3v3v3v3(pos_r, points[0], points[1], points[2], points[3], weights);
-  }
-}
-
-static void subdiv_mesh_vertex_of_loose_edge_interpolate(SubdivMeshContext *ctx,
-                                                         const MEdge *coarse_edge,
-                                                         const float u,
-                                                         const int subdiv_vertex_index)
-{
-  const Mesh *coarse_mesh = ctx->coarse_mesh;
-  Mesh *subdiv_mesh = ctx->subdiv_mesh;
-  /* This is never used for end-points (which are copied from the original). */
-  BLI_assert(u > 0.0f);
-  BLI_assert(u < 1.0f);
-  const float interpolation_weights[2] = {1.0f - u, u};
-  const int coarse_vertex_indices[2] = {coarse_edge->v1, coarse_edge->v2};
-  CustomData_interp(&coarse_mesh->vdata,
-                    &subdiv_mesh->vdata,
-                    coarse_vertex_indices,
-                    interpolation_weights,
-                    NULL,
-                    2,
-                    subdiv_vertex_index);
-  if (ctx->vert_origindex != NULL) {
-    ctx->vert_origindex[subdiv_vertex_index] = ORIGINDEX_NONE;
-  }
-}
-
-static void subdiv_mesh_vertex_of_loose_edge(const struct SubdivForeachContext *foreach_context,
-                                             void *UNUSED(tls),
-                                             const int coarse_edge_index,
-                                             const float u,
-                                             const int subdiv_vertex_index)
-{
-  SubdivMeshContext *ctx = foreach_context->user_data;
-  const Mesh *coarse_mesh = ctx->coarse_mesh;
-  const MEdge *coarse_edge = &coarse_mesh->medge[coarse_edge_index];
-  Mesh *subdiv_mesh = ctx->subdiv_mesh;
-  MVert *subdiv_mvert = subdiv_mesh->mvert;
-  const bool is_simple = ctx->subdiv->settings.is_simple;
-  /* Interpolate custom data when not an end point.
-   * This data has already been copied from the original vertex by #subdiv_mesh_vertex_loose. */
-  if (!ELEM(u, 0.0, 1.0)) {
-    subdiv_mesh_vertex_of_loose_edge_interpolate(ctx, coarse_edge, u, subdiv_vertex_index);
-  }
-  /* Interpolate coordinate. */
-  MVert *subdiv_vertex = &subdiv_mvert[subdiv_vertex_index];
-  BKE_subdiv_mesh_interpolate_position_on_edge(
-      coarse_mesh, coarse_edge, is_simple, u, subdiv_vertex->co);
-  /* Reset flags and such. */
-  subdiv_vertex->flag = 0;
-  /* TODO(sergey): This matches old behavior, but we can as well interpolate
-   * it. Maybe even using vertex varying attributes. */
-  subdiv_vertex->bweight = 0.0f;
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Initialization
- * \{ */
-
-static void setup_foreach_callbacks(const SubdivMeshContext *subdiv_context,
-                                    SubdivForeachContext *foreach_context)
-{
-  memset(foreach_context, 0, sizeof(*foreach_context));
-  /* General information. */
-  foreach_context->topology_info = subdiv_mesh_topology_info;
-  /* Every boundary geometry. Used for displacement averaging. */
-  if (subdiv_context->have_displacement) {
-    foreach_context->vertex_every_corner = subdiv_mesh_vertex_displacement_every_corner;
-    foreach_context->vertex_every_edge = subdiv_mesh_vertex_displacement_every_edge;
-  }
-  foreach_context->vertex_corner = subdiv_mesh_vertex_corner;
-  foreach_context->vertex_edge = subdiv_mesh_vertex_edge;
-  foreach_context->vertex_inner = subdiv_mesh_vertex_inner;
-  foreach_context->edge = subdiv_mesh_edge;
-  foreach_context->loop = subdiv_mesh_loop;
-  foreach_context->poly = subdiv_mesh_poly;
-  foreach_context->vertex_loose = subdiv_mesh_vertex_loose;
-  foreach_context->vertex_of_loose_edge = subdiv_mesh_vertex_of_loose_edge;
-  foreach_context->user_data_tls_free = subdiv_mesh_tls_free;
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Public entry point
- * \{ */
-
-Mesh *BKE_subdiv_to_mesh(Subdiv *subdiv,
-                         const SubdivToMeshSettings *settings,
-                         const Mesh *coarse_mesh)
-{
-  BKE_subdiv_stats_begin(&subdiv->stats, SUBDIV_STATS_SUBDIV_TO_MESH);
-  /* Make sure evaluator is up to date with possible new topology, and that
-   * it is refined for the new positions of coarse vertices. */
-  if (!BKE_subdiv_eval_begin_from_mesh(
-          subdiv, coarse_mesh, NULL, SUBDIV_EVALUATOR_TYPE_CPU, NULL)) {
-    /* This could happen in two situations:
-     * - OpenSubdiv is disabled.
-     * - Something totally bad happened, and OpenSubdiv rejected our
-     *   topology.
-     * In either way, we can't safely continue. */
-    if (coarse_mesh->totpoly) {
-      BKE_subdiv_stats_end(&subdiv->stats, SUBDIV_STATS_SUBDIV_TO_MESH);
-      return NULL;
-    }
-  }
-  /* Initialize subdivision mesh creation context. */
-  SubdivMeshContext subdiv_context = {0};
-  subdiv_context.settings = settings;
-  subdiv_context.coarse_mesh = coarse_mesh;
-  subdiv_context.subdiv = subdiv;
-  subdiv_context.have_displacement = (subdiv->displacement_evaluator != NULL);
-  /* Multi-threaded traversal/evaluation. */
-  BKE_subdiv_stats_begin(&subdiv->stats, SUBDIV_STATS_SUBDIV_TO_MESH_GEOMETRY);
-  SubdivForeachContext foreach_context;
-  setup_foreach_callbacks(&subdiv_context, &foreach_context);
-  SubdivMeshTLS tls = {0};
-  foreach_context.user_data = &subdiv_context;
-  foreach_context.user_data_tls_size = sizeof(SubdivMeshTLS);
-  foreach_context.user_data_tls = &tls;
-  BKE_subdiv_foreach_subdiv_geometry(subdiv, &foreach_context, settings, coarse_mesh);
-  BKE_subdiv_stats_end(&subdiv->stats, SUBDIV_STATS_SUBDIV_TO_MESH_GEOMETRY);
-  Mesh *result = subdiv_context.subdiv_mesh;
-  // BKE_mesh_validate(result, true, true);
-  BKE_subdiv_stats_end(&subdiv->stats, SUBDIV_STATS_SUBDIV_TO_MESH);
-  /* Using normals from the limit surface gives different results than Blender's vertex normal
-   * calculation. Since vertex normals are supposed to be a consistent cache, don't bother
-   * calculating them here. The work may have been pointless anyway if the mesh is deformed or
-   * changed afterwards. */
-  BLI_assert(BKE_mesh_vertex_normals_are_dirty(result) || BKE_mesh_poly_normals_are_dirty(result));
-  /* Free used memory. */
-  subdiv_mesh_context_free(&subdiv_context);
-  return result;
-}
-
-/** \} */
diff --git a/source/blender/blenkernel/intern/subdiv_mesh.cc b/source/blender/blenkernel/intern/subdiv_mesh.cc
new file mode 100644
index 00000000000..44bdd6e6d06
--- /dev/null
+++ b/source/blender/blenkernel/intern/subdiv_mesh.cc
@@ -0,0 +1,1230 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright 2018 Blender Foundation. All rights reserved. */
+
+/** \file
+ * \ingroup bke
+ */
+
+#include 
+
+#include "atomic_ops.h"
+
+#include "DNA_key_types.h"
+#include "DNA_mesh_types.h"
+#include "DNA_meshdata_types.h"
+
+#include "BLI_array.hh"
+#include "BLI_bitmap.h"
+#include "BLI_math_vector.h"
+
+#include "BKE_customdata.h"
+#include "BKE_key.h"
+#include "BKE_mesh.h"
+#include "BKE_mesh_mapping.h"
+#include "BKE_subdiv.h"
+#include "BKE_subdiv_eval.h"
+#include "BKE_subdiv_foreach.h"
+#include "BKE_subdiv_mesh.h"
+
+#include "MEM_guardedalloc.h"
+
+using blender::Span;
+
+/* -------------------------------------------------------------------- */
+/** \name Subdivision Context
+ * \{ */
+
+struct SubdivMeshContext {
+  const SubdivToMeshSettings *settings;
+  const Mesh *coarse_mesh;
+  const MVert *coarse_verts;
+  const MEdge *coarse_edges;
+  const MPoly *coarse_polys;
+  const MLoop *coarse_loops;
+
+  Subdiv *subdiv;
+  Mesh *subdiv_mesh;
+  MVert *subdiv_verts;
+  MEdge *subdiv_edges;
+  MPoly *subdiv_polys;
+  MLoop *subdiv_loops;
+
+  /* Cached custom data arrays for faster access. */
+  int *vert_origindex;
+  int *edge_origindex;
+  int *loop_origindex;
+  int *poly_origindex;
+  /* UV layers interpolation. */
+  int num_uv_layers;
+  MLoopUV *uv_layers[MAX_MTFACE];
+  /* Original coordinates (ORCO) interpolation. */
+  float (*orco)[3];
+  float (*cloth_orco)[3];
+  /* Per-subdivided vertex counter of averaged values. */
+  int *accumulated_counters;
+  bool have_displacement;
+
+  /* Lazily initialize a map from vertices to connected edges. */
+  std::mutex vert_to_edge_map_mutex;
+  int *vert_to_edge_buffer;
+  MeshElemMap *vert_to_edge_map;
+};
+
+static void subdiv_mesh_ctx_cache_uv_layers(SubdivMeshContext *ctx)
+{
+  Mesh *subdiv_mesh = ctx->subdiv_mesh;
+  ctx->num_uv_layers = CustomData_number_of_layers(&subdiv_mesh->ldata, CD_MLOOPUV);
+  for (int layer_index = 0; layer_index < ctx->num_uv_layers; layer_index++) {
+    ctx->uv_layers[layer_index] = static_cast(
+        CustomData_get_layer_n(&subdiv_mesh->ldata, CD_MLOOPUV, layer_index));
+  }
+}
+
+static void subdiv_mesh_ctx_cache_custom_data_layers(SubdivMeshContext *ctx)
+{
+  Mesh *subdiv_mesh = ctx->subdiv_mesh;
+  ctx->subdiv_verts = BKE_mesh_verts_for_write(subdiv_mesh);
+  ctx->subdiv_edges = BKE_mesh_edges_for_write(subdiv_mesh);
+  ctx->subdiv_polys = BKE_mesh_polys_for_write(subdiv_mesh);
+  ctx->subdiv_loops = BKE_mesh_loops_for_write(subdiv_mesh);
+  /* Pointers to original indices layers. */
+  ctx->vert_origindex = static_cast(
+      CustomData_get_layer(&subdiv_mesh->vdata, CD_ORIGINDEX));
+  ctx->edge_origindex = static_cast(
+      CustomData_get_layer(&subdiv_mesh->edata, CD_ORIGINDEX));
+  ctx->loop_origindex = static_cast(
+      CustomData_get_layer(&subdiv_mesh->ldata, CD_ORIGINDEX));
+  ctx->poly_origindex = static_cast(
+      CustomData_get_layer(&subdiv_mesh->pdata, CD_ORIGINDEX));
+  /* UV layers interpolation. */
+  subdiv_mesh_ctx_cache_uv_layers(ctx);
+  /* Orco interpolation. */
+  ctx->orco = static_cast(CustomData_get_layer(&subdiv_mesh->vdata, CD_ORCO));
+  ctx->cloth_orco = static_cast(
+      CustomData_get_layer(&subdiv_mesh->vdata, CD_CLOTH_ORCO));
+}
+
+static void subdiv_mesh_prepare_accumulator(SubdivMeshContext *ctx, int num_vertices)
+{
+  if (!ctx->have_displacement) {
+    return;
+  }
+  ctx->accumulated_counters = static_cast(
+      MEM_calloc_arrayN(num_vertices, sizeof(*ctx->accumulated_counters), __func__));
+}
+
+static void subdiv_mesh_context_free(SubdivMeshContext *ctx)
+{
+  MEM_SAFE_FREE(ctx->accumulated_counters);
+  MEM_SAFE_FREE(ctx->vert_to_edge_buffer);
+  MEM_SAFE_FREE(ctx->vert_to_edge_map);
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Loop custom data copy helpers
+ * \{ */
+
+struct LoopsOfPtex {
+  /* First loop of the ptex, starts at ptex (0, 0) and goes in u direction. */
+  const MLoop *first_loop;
+  /* Last loop of the ptex, starts at ptex (0, 0) and goes in v direction. */
+  const MLoop *last_loop;
+  /* For quad coarse faces only. */
+  const MLoop *second_loop;
+  const MLoop *third_loop;
+};
+
+static void loops_of_ptex_get(const SubdivMeshContext *ctx,
+                              LoopsOfPtex *loops_of_ptex,
+                              const MPoly *coarse_poly,
+                              const int ptex_of_poly_index)
+{
+  const MLoop *coarse_mloop = ctx->coarse_loops;
+  const int first_ptex_loop_index = coarse_poly->loopstart + ptex_of_poly_index;
+  /* Loop which look in the (opposite) V direction of the current
+   * ptex face.
+   *
+   * TODO(sergey): Get rid of using module on every iteration. */
+  const int last_ptex_loop_index = coarse_poly->loopstart +
+                                   (ptex_of_poly_index + coarse_poly->totloop - 1) %
+                                       coarse_poly->totloop;
+  loops_of_ptex->first_loop = &coarse_mloop[first_ptex_loop_index];
+  loops_of_ptex->last_loop = &coarse_mloop[last_ptex_loop_index];
+  if (coarse_poly->totloop == 4) {
+    loops_of_ptex->second_loop = loops_of_ptex->first_loop + 1;
+    loops_of_ptex->third_loop = loops_of_ptex->first_loop + 2;
+  }
+  else {
+    loops_of_ptex->second_loop = nullptr;
+    loops_of_ptex->third_loop = nullptr;
+  }
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Vertex custom data interpolation helpers
+ * \{ */
+
+/* TODO(sergey): Somehow de-duplicate with loops storage, without too much
+ * exception cases all over the code. */
+
+struct VerticesForInterpolation {
+  /* This field points to a vertex data which is to be used for interpolation.
+   * The idea is to avoid unnecessary allocations for regular faces, where
+   * we can simply use corner vertices. */
+  const CustomData *vertex_data;
+  /* Vertices data calculated for ptex corners. There are always 4 elements
+   * in this custom data, aligned the following way:
+   *
+   *   index 0 -> uv (0, 0)
+   *   index 1 -> uv (0, 1)
+   *   index 2 -> uv (1, 1)
+   *   index 3 -> uv (1, 0)
+   *
+   * Is allocated for non-regular faces (triangles and n-gons). */
+  CustomData vertex_data_storage;
+  bool vertex_data_storage_allocated;
+  /* Indices within vertex_data to interpolate for. The indices are aligned
+   * with uv coordinates in a similar way as indices in loop_data_storage. */
+  int vertex_indices[4];
+};
+
+static void vertex_interpolation_init(const SubdivMeshContext *ctx,
+                                      VerticesForInterpolation *vertex_interpolation,
+                                      const MPoly *coarse_poly)
+{
+  const Mesh *coarse_mesh = ctx->coarse_mesh;
+  const MLoop *coarse_mloop = ctx->coarse_loops;
+  if (coarse_poly->totloop == 4) {
+    vertex_interpolation->vertex_data = &coarse_mesh->vdata;
+    vertex_interpolation->vertex_indices[0] = coarse_mloop[coarse_poly->loopstart + 0].v;
+    vertex_interpolation->vertex_indices[1] = coarse_mloop[coarse_poly->loopstart + 1].v;
+    vertex_interpolation->vertex_indices[2] = coarse_mloop[coarse_poly->loopstart + 2].v;
+    vertex_interpolation->vertex_indices[3] = coarse_mloop[coarse_poly->loopstart + 3].v;
+    vertex_interpolation->vertex_data_storage_allocated = false;
+  }
+  else {
+    vertex_interpolation->vertex_data = &vertex_interpolation->vertex_data_storage;
+    /* Allocate storage for loops corresponding to ptex corners. */
+    CustomData_copy(&ctx->coarse_mesh->vdata,
+                    &vertex_interpolation->vertex_data_storage,
+                    CD_MASK_EVERYTHING.vmask,
+                    CD_SET_DEFAULT,
+                    4);
+    /* Initialize indices. */
+    vertex_interpolation->vertex_indices[0] = 0;
+    vertex_interpolation->vertex_indices[1] = 1;
+    vertex_interpolation->vertex_indices[2] = 2;
+    vertex_interpolation->vertex_indices[3] = 3;
+    vertex_interpolation->vertex_data_storage_allocated = true;
+    /* Interpolate center of poly right away, it stays unchanged for all
+     * ptex faces. */
+    const float weight = 1.0f / (float)coarse_poly->totloop;
+    blender::Array weights(coarse_poly->totloop);
+    blender::Array indices(coarse_poly->totloop);
+    for (int i = 0; i < coarse_poly->totloop; i++) {
+      weights[i] = weight;
+      indices[i] = coarse_mloop[coarse_poly->loopstart + i].v;
+    }
+    CustomData_interp(&coarse_mesh->vdata,
+                      &vertex_interpolation->vertex_data_storage,
+                      indices.data(),
+                      weights.data(),
+                      nullptr,
+                      coarse_poly->totloop,
+                      2);
+  }
+}
+
+static void vertex_interpolation_from_corner(const SubdivMeshContext *ctx,
+                                             VerticesForInterpolation *vertex_interpolation,
+                                             const MPoly *coarse_poly,
+                                             const int corner)
+{
+  if (coarse_poly->totloop == 4) {
+    /* Nothing to do, all indices and data is already assigned. */
+  }
+  else {
+    const CustomData *vertex_data = &ctx->coarse_mesh->vdata;
+    const MLoop *coarse_mloop = ctx->coarse_loops;
+    LoopsOfPtex loops_of_ptex;
+    loops_of_ptex_get(ctx, &loops_of_ptex, coarse_poly, corner);
+    /* Ptex face corner corresponds to a poly loop with same index. */
+    CustomData_copy_data(vertex_data,
+                         &vertex_interpolation->vertex_data_storage,
+                         coarse_mloop[coarse_poly->loopstart + corner].v,
+                         0,
+                         1);
+    /* Interpolate remaining ptex face corners, which hits loops
+     * middle points.
+     *
+     * TODO(sergey): Re-use one of interpolation results from previous
+     * iteration. */
+    const float weights[2] = {0.5f, 0.5f};
+    const int first_loop_index = loops_of_ptex.first_loop - coarse_mloop;
+    const int last_loop_index = loops_of_ptex.last_loop - coarse_mloop;
+    const int first_indices[2] = {
+        static_cast(coarse_mloop[first_loop_index].v),
+        static_cast(
+            coarse_mloop[coarse_poly->loopstart +
+                         (first_loop_index - coarse_poly->loopstart + 1) % coarse_poly->totloop]
+                .v)};
+    const int last_indices[2] = {
+        static_cast(coarse_mloop[first_loop_index].v),
+        static_cast(coarse_mloop[last_loop_index].v),
+    };
+    CustomData_interp(vertex_data,
+                      &vertex_interpolation->vertex_data_storage,
+                      first_indices,
+                      weights,
+                      nullptr,
+                      2,
+                      1);
+    CustomData_interp(vertex_data,
+                      &vertex_interpolation->vertex_data_storage,
+                      last_indices,
+                      weights,
+                      nullptr,
+                      2,
+                      3);
+  }
+}
+
+static void vertex_interpolation_end(VerticesForInterpolation *vertex_interpolation)
+{
+  if (vertex_interpolation->vertex_data_storage_allocated) {
+    CustomData_free(&vertex_interpolation->vertex_data_storage, 4);
+  }
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Loop custom data interpolation helpers
+ * \{ */
+
+struct LoopsForInterpolation {
+  /* This field points to a loop data which is to be used for interpolation.
+   * The idea is to avoid unnecessary allocations for regular faces, where
+   * we can simply interpolate corner vertices. */
+  const CustomData *loop_data;
+  /* Loops data calculated for ptex corners. There are always 4 elements
+   * in this custom data, aligned the following way:
+   *
+   *   index 0 -> uv (0, 0)
+   *   index 1 -> uv (0, 1)
+   *   index 2 -> uv (1, 1)
+   *   index 3 -> uv (1, 0)
+   *
+   * Is allocated for non-regular faces (triangles and n-gons). */
+  CustomData loop_data_storage;
+  bool loop_data_storage_allocated;
+  /* Indices within loop_data to interpolate for. The indices are aligned with
+   * uv coordinates in a similar way as indices in loop_data_storage. */
+  int loop_indices[4];
+};
+
+static void loop_interpolation_init(const SubdivMeshContext *ctx,
+                                    LoopsForInterpolation *loop_interpolation,
+                                    const MPoly *coarse_poly)
+{
+  const Mesh *coarse_mesh = ctx->coarse_mesh;
+  if (coarse_poly->totloop == 4) {
+    loop_interpolation->loop_data = &coarse_mesh->ldata;
+    loop_interpolation->loop_indices[0] = coarse_poly->loopstart + 0;
+    loop_interpolation->loop_indices[1] = coarse_poly->loopstart + 1;
+    loop_interpolation->loop_indices[2] = coarse_poly->loopstart + 2;
+    loop_interpolation->loop_indices[3] = coarse_poly->loopstart + 3;
+    loop_interpolation->loop_data_storage_allocated = false;
+  }
+  else {
+    loop_interpolation->loop_data = &loop_interpolation->loop_data_storage;
+    /* Allocate storage for loops corresponding to ptex corners. */
+    CustomData_copy(&ctx->coarse_mesh->ldata,
+                    &loop_interpolation->loop_data_storage,
+                    CD_MASK_EVERYTHING.lmask,
+                    CD_SET_DEFAULT,
+                    4);
+    /* Initialize indices. */
+    loop_interpolation->loop_indices[0] = 0;
+    loop_interpolation->loop_indices[1] = 1;
+    loop_interpolation->loop_indices[2] = 2;
+    loop_interpolation->loop_indices[3] = 3;
+    loop_interpolation->loop_data_storage_allocated = true;
+    /* Interpolate center of poly right away, it stays unchanged for all
+     * ptex faces. */
+    const float weight = 1.0f / (float)coarse_poly->totloop;
+    blender::Array weights(coarse_poly->totloop);
+    blender::Array indices(coarse_poly->totloop);
+    for (int i = 0; i < coarse_poly->totloop; i++) {
+      weights[i] = weight;
+      indices[i] = coarse_poly->loopstart + i;
+    }
+    CustomData_interp(&coarse_mesh->ldata,
+                      &loop_interpolation->loop_data_storage,
+                      indices.data(),
+                      weights.data(),
+                      nullptr,
+                      coarse_poly->totloop,
+                      2);
+  }
+}
+
+static void loop_interpolation_from_corner(const SubdivMeshContext *ctx,
+                                           LoopsForInterpolation *loop_interpolation,
+                                           const MPoly *coarse_poly,
+                                           const int corner)
+{
+  if (coarse_poly->totloop == 4) {
+    /* Nothing to do, all indices and data is already assigned. */
+  }
+  else {
+    const CustomData *loop_data = &ctx->coarse_mesh->ldata;
+    const MLoop *coarse_mloop = ctx->coarse_loops;
+    LoopsOfPtex loops_of_ptex;
+    loops_of_ptex_get(ctx, &loops_of_ptex, coarse_poly, corner);
+    /* Ptex face corner corresponds to a poly loop with same index. */
+    CustomData_free_elem(&loop_interpolation->loop_data_storage, 0, 1);
+    CustomData_copy_data(
+        loop_data, &loop_interpolation->loop_data_storage, coarse_poly->loopstart + corner, 0, 1);
+    /* Interpolate remaining ptex face corners, which hits loops
+     * middle points.
+     *
+     * TODO(sergey): Re-use one of interpolation results from previous
+     * iteration. */
+    const float weights[2] = {0.5f, 0.5f};
+    const int base_loop_index = coarse_poly->loopstart;
+    const int first_loop_index = loops_of_ptex.first_loop - coarse_mloop;
+    const int second_loop_index = base_loop_index +
+                                  (first_loop_index - base_loop_index + 1) % coarse_poly->totloop;
+    const int first_indices[2] = {first_loop_index, second_loop_index};
+    const int last_indices[2] = {
+        static_cast(loops_of_ptex.last_loop - coarse_mloop),
+        static_cast(loops_of_ptex.first_loop - coarse_mloop),
+    };
+    CustomData_interp(
+        loop_data, &loop_interpolation->loop_data_storage, first_indices, weights, nullptr, 2, 1);
+    CustomData_interp(
+        loop_data, &loop_interpolation->loop_data_storage, last_indices, weights, nullptr, 2, 3);
+  }
+}
+
+static void loop_interpolation_end(LoopsForInterpolation *loop_interpolation)
+{
+  if (loop_interpolation->loop_data_storage_allocated) {
+    CustomData_free(&loop_interpolation->loop_data_storage, 4);
+  }
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name TLS
+ * \{ */
+
+struct SubdivMeshTLS {
+  bool vertex_interpolation_initialized;
+  VerticesForInterpolation vertex_interpolation;
+  const MPoly *vertex_interpolation_coarse_poly;
+  int vertex_interpolation_coarse_corner;
+
+  bool loop_interpolation_initialized;
+  LoopsForInterpolation loop_interpolation;
+  const MPoly *loop_interpolation_coarse_poly;
+  int loop_interpolation_coarse_corner;
+};
+
+static void subdiv_mesh_tls_free(void *tls_v)
+{
+  SubdivMeshTLS *tls = static_cast(tls_v);
+  if (tls->vertex_interpolation_initialized) {
+    vertex_interpolation_end(&tls->vertex_interpolation);
+  }
+  if (tls->loop_interpolation_initialized) {
+    loop_interpolation_end(&tls->loop_interpolation);
+  }
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Evaluation helper functions
+ * \{ */
+
+static void subdiv_vertex_orco_evaluate(const SubdivMeshContext *ctx,
+                                        const int ptex_face_index,
+                                        const float u,
+                                        const float v,
+                                        const int subdiv_vertex_index)
+{
+  if (ctx->orco || ctx->cloth_orco) {
+    float vertex_data[6];
+    BKE_subdiv_eval_vertex_data(ctx->subdiv, ptex_face_index, u, v, vertex_data);
+
+    if (ctx->orco) {
+      copy_v3_v3(ctx->orco[subdiv_vertex_index], vertex_data);
+      if (ctx->cloth_orco) {
+        copy_v3_v3(ctx->orco[subdiv_vertex_index], vertex_data + 3);
+      }
+    }
+    else if (ctx->cloth_orco) {
+      copy_v3_v3(ctx->orco[subdiv_vertex_index], vertex_data);
+    }
+  }
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Accumulation helpers
+ * \{ */
+
+static void subdiv_accumulate_vertex_displacement(SubdivMeshContext *ctx,
+                                                  const int ptex_face_index,
+                                                  const float u,
+                                                  const float v,
+                                                  MVert *subdiv_vert)
+{
+  /* Accumulate displacement. */
+  Subdiv *subdiv = ctx->subdiv;
+  const int subdiv_vertex_index = subdiv_vert - ctx->subdiv_verts;
+  float dummy_P[3], dPdu[3], dPdv[3], D[3];
+  BKE_subdiv_eval_limit_point_and_derivatives(subdiv, ptex_face_index, u, v, dummy_P, dPdu, dPdv);
+
+  /* NOTE: The subdivided mesh is allocated in this module, and its vertices are kept at zero
+   * locations as a default calloc(). */
+  BKE_subdiv_eval_displacement(subdiv, ptex_face_index, u, v, dPdu, dPdv, D);
+  add_v3_v3(subdiv_vert->co, D);
+
+  if (ctx->accumulated_counters) {
+    ++ctx->accumulated_counters[subdiv_vertex_index];
+  }
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Callbacks
+ * \{ */
+
+static bool subdiv_mesh_topology_info(const SubdivForeachContext *foreach_context,
+                                      const int num_vertices,
+                                      const int num_edges,
+                                      const int num_loops,
+                                      const int num_polygons,
+                                      const int *UNUSED(subdiv_polygon_offset))
+{
+  /* Multi-resolution grid data will be applied or become invalid after subdivision,
+   * so don't try to preserve it and use memory. */
+  CustomData_MeshMasks mask = CD_MASK_EVERYTHING;
+  mask.lmask &= ~CD_MASK_MULTIRES_GRIDS;
+
+  SubdivMeshContext *subdiv_context = static_cast(foreach_context->user_data);
+  subdiv_context->subdiv_mesh = BKE_mesh_new_nomain_from_template_ex(
+      subdiv_context->coarse_mesh, num_vertices, num_edges, 0, num_loops, num_polygons, mask);
+  subdiv_mesh_ctx_cache_custom_data_layers(subdiv_context);
+  subdiv_mesh_prepare_accumulator(subdiv_context, num_vertices);
+  MEM_SAFE_FREE(subdiv_context->subdiv_mesh->runtime.subsurf_face_dot_tags);
+  subdiv_context->subdiv_mesh->runtime.subsurf_face_dot_tags = BLI_BITMAP_NEW(num_vertices,
+                                                                              __func__);
+  return true;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Vertex subdivision process
+ * \{ */
+
+static void subdiv_vertex_data_copy(const SubdivMeshContext *ctx,
+                                    const MVert *coarse_vertex,
+                                    MVert *subdiv_vertex)
+{
+  const Mesh *coarse_mesh = ctx->coarse_mesh;
+  const int coarse_vertex_index = coarse_vertex - ctx->coarse_verts;
+  const int subdiv_vertex_index = subdiv_vertex - ctx->subdiv_verts;
+  CustomData_copy_data(
+      &coarse_mesh->vdata, &ctx->subdiv_mesh->vdata, coarse_vertex_index, subdiv_vertex_index, 1);
+}
+
+static void subdiv_vertex_data_interpolate(const SubdivMeshContext *ctx,
+                                           MVert *subdiv_vertex,
+                                           const VerticesForInterpolation *vertex_interpolation,
+                                           const float u,
+                                           const float v)
+{
+  const int subdiv_vertex_index = subdiv_vertex - ctx->subdiv_verts;
+  const float weights[4] = {(1.0f - u) * (1.0f - v), u * (1.0f - v), u * v, (1.0f - u) * v};
+  CustomData_interp(vertex_interpolation->vertex_data,
+                    &ctx->subdiv_mesh->vdata,
+                    vertex_interpolation->vertex_indices,
+                    weights,
+                    nullptr,
+                    4,
+                    subdiv_vertex_index);
+  if (ctx->vert_origindex != nullptr) {
+    ctx->vert_origindex[subdiv_vertex_index] = ORIGINDEX_NONE;
+  }
+}
+
+static void evaluate_vertex_and_apply_displacement_copy(const SubdivMeshContext *ctx,
+                                                        const int ptex_face_index,
+                                                        const float u,
+                                                        const float v,
+                                                        const MVert *coarse_vert,
+                                                        MVert *subdiv_vert)
+{
+  const int subdiv_vertex_index = subdiv_vert - ctx->subdiv_verts;
+  /* Displacement is accumulated in subdiv vertex position.
+   * Needs to be backed up before copying data from original vertex. */
+  float D[3] = {0.0f, 0.0f, 0.0f};
+  if (ctx->have_displacement) {
+    const float inv_num_accumulated = 1.0f / ctx->accumulated_counters[subdiv_vertex_index];
+    copy_v3_v3(D, subdiv_vert->co);
+    mul_v3_fl(D, inv_num_accumulated);
+  }
+  /* Copy custom data and evaluate position. */
+  subdiv_vertex_data_copy(ctx, coarse_vert, subdiv_vert);
+  BKE_subdiv_eval_limit_point(ctx->subdiv, ptex_face_index, u, v, subdiv_vert->co);
+  /* Apply displacement. */
+  add_v3_v3(subdiv_vert->co, D);
+  /* Evaluate undeformed texture coordinate. */
+  subdiv_vertex_orco_evaluate(ctx, ptex_face_index, u, v, subdiv_vertex_index);
+  /* Remove face-dot flag. This can happen if there is more than one subsurf modifier. */
+  BLI_BITMAP_DISABLE(ctx->subdiv_mesh->runtime.subsurf_face_dot_tags, subdiv_vertex_index);
+}
+
+static void evaluate_vertex_and_apply_displacement_interpolate(
+    const SubdivMeshContext *ctx,
+    const int ptex_face_index,
+    const float u,
+    const float v,
+    VerticesForInterpolation *vertex_interpolation,
+    MVert *subdiv_vert)
+{
+  const int subdiv_vertex_index = subdiv_vert - ctx->subdiv_verts;
+  /* Displacement is accumulated in subdiv vertex position.
+   * Needs to be backed up before copying data from original vertex. */
+  float D[3] = {0.0f, 0.0f, 0.0f};
+  if (ctx->have_displacement) {
+    const float inv_num_accumulated = 1.0f / ctx->accumulated_counters[subdiv_vertex_index];
+    copy_v3_v3(D, subdiv_vert->co);
+    mul_v3_fl(D, inv_num_accumulated);
+  }
+  /* Interpolate custom data and evaluate position. */
+  subdiv_vertex_data_interpolate(ctx, subdiv_vert, vertex_interpolation, u, v);
+  BKE_subdiv_eval_limit_point(ctx->subdiv, ptex_face_index, u, v, subdiv_vert->co);
+  /* Apply displacement. */
+  add_v3_v3(subdiv_vert->co, D);
+  /* Evaluate undeformed texture coordinate. */
+  subdiv_vertex_orco_evaluate(ctx, ptex_face_index, u, v, subdiv_vertex_index);
+}
+
+static void subdiv_mesh_vertex_displacement_every_corner_or_edge(
+    const SubdivForeachContext *foreach_context,
+    void *UNUSED(tls),
+    const int ptex_face_index,
+    const float u,
+    const float v,
+    const int subdiv_vertex_index)
+{
+  SubdivMeshContext *ctx = static_cast(foreach_context->user_data);
+  MVert *subdiv_vert = &ctx->subdiv_verts[subdiv_vertex_index];
+  subdiv_accumulate_vertex_displacement(ctx, ptex_face_index, u, v, subdiv_vert);
+}
+
+static void subdiv_mesh_vertex_displacement_every_corner(
+    const SubdivForeachContext *foreach_context,
+    void *tls,
+    const int ptex_face_index,
+    const float u,
+    const float v,
+    const int UNUSED(coarse_vertex_index),
+    const int UNUSED(coarse_poly_index),
+    const int UNUSED(coarse_corner),
+    const int subdiv_vertex_index)
+{
+  subdiv_mesh_vertex_displacement_every_corner_or_edge(
+      foreach_context, tls, ptex_face_index, u, v, subdiv_vertex_index);
+}
+
+static void subdiv_mesh_vertex_displacement_every_edge(const SubdivForeachContext *foreach_context,
+                                                       void *tls,
+                                                       const int ptex_face_index,
+                                                       const float u,
+                                                       const float v,
+                                                       const int UNUSED(coarse_edge_index),
+                                                       const int UNUSED(coarse_poly_index),
+                                                       const int UNUSED(coarse_corner),
+                                                       const int subdiv_vertex_index)
+{
+  subdiv_mesh_vertex_displacement_every_corner_or_edge(
+      foreach_context, tls, ptex_face_index, u, v, subdiv_vertex_index);
+}
+
+static void subdiv_mesh_vertex_corner(const SubdivForeachContext *foreach_context,
+                                      void *UNUSED(tls),
+                                      const int ptex_face_index,
+                                      const float u,
+                                      const float v,
+                                      const int coarse_vertex_index,
+                                      const int UNUSED(coarse_poly_index),
+                                      const int UNUSED(coarse_corner),
+                                      const int subdiv_vertex_index)
+{
+  BLI_assert(coarse_vertex_index != ORIGINDEX_NONE);
+  SubdivMeshContext *ctx = static_cast(foreach_context->user_data);
+  const MVert *coarse_vert = &ctx->coarse_verts[coarse_vertex_index];
+  MVert *subdiv_vert = &ctx->subdiv_verts[subdiv_vertex_index];
+  evaluate_vertex_and_apply_displacement_copy(
+      ctx, ptex_face_index, u, v, coarse_vert, subdiv_vert);
+}
+
+static void subdiv_mesh_ensure_vertex_interpolation(SubdivMeshContext *ctx,
+                                                    SubdivMeshTLS *tls,
+                                                    const MPoly *coarse_poly,
+                                                    const int coarse_corner)
+{
+  /* Check whether we've moved to another corner or polygon. */
+  if (tls->vertex_interpolation_initialized) {
+    if (tls->vertex_interpolation_coarse_poly != coarse_poly ||
+        tls->vertex_interpolation_coarse_corner != coarse_corner) {
+      vertex_interpolation_end(&tls->vertex_interpolation);
+      tls->vertex_interpolation_initialized = false;
+    }
+  }
+  /* Initialize the interpolation. */
+  if (!tls->vertex_interpolation_initialized) {
+    vertex_interpolation_init(ctx, &tls->vertex_interpolation, coarse_poly);
+  }
+  /* Update it for a new corner if needed. */
+  if (!tls->vertex_interpolation_initialized ||
+      tls->vertex_interpolation_coarse_corner != coarse_corner) {
+    vertex_interpolation_from_corner(ctx, &tls->vertex_interpolation, coarse_poly, coarse_corner);
+  }
+  /* Store settings used for the current state of interpolator. */
+  tls->vertex_interpolation_initialized = true;
+  tls->vertex_interpolation_coarse_poly = coarse_poly;
+  tls->vertex_interpolation_coarse_corner = coarse_corner;
+}
+
+static void subdiv_mesh_vertex_edge(const SubdivForeachContext *foreach_context,
+                                    void *tls_v,
+                                    const int ptex_face_index,
+                                    const float u,
+                                    const float v,
+                                    const int UNUSED(coarse_edge_index),
+                                    const int coarse_poly_index,
+                                    const int coarse_corner,
+                                    const int subdiv_vertex_index)
+{
+  SubdivMeshContext *ctx = static_cast(foreach_context->user_data);
+  SubdivMeshTLS *tls = static_cast(tls_v);
+  const MPoly *coarse_poly = &ctx->coarse_polys[coarse_poly_index];
+  MVert *subdiv_vert = &ctx->subdiv_verts[subdiv_vertex_index];
+  subdiv_mesh_ensure_vertex_interpolation(ctx, tls, coarse_poly, coarse_corner);
+  evaluate_vertex_and_apply_displacement_interpolate(
+      ctx, ptex_face_index, u, v, &tls->vertex_interpolation, subdiv_vert);
+}
+
+static bool subdiv_mesh_is_center_vertex(const MPoly *coarse_poly, const float u, const float v)
+{
+  if (coarse_poly->totloop == 4) {
+    if (u == 0.5f && v == 0.5f) {
+      return true;
+    }
+  }
+  else {
+    if (u == 1.0f && v == 1.0f) {
+      return true;
+    }
+  }
+  return false;
+}
+
+static void subdiv_mesh_tag_center_vertex(const MPoly *coarse_poly,
+                                          const int subdiv_vertex_index,
+                                          const float u,
+                                          const float v,
+                                          Mesh *subdiv_mesh)
+{
+  if (subdiv_mesh_is_center_vertex(coarse_poly, u, v)) {
+    BLI_BITMAP_ENABLE(subdiv_mesh->runtime.subsurf_face_dot_tags, subdiv_vertex_index);
+  }
+}
+
+static void subdiv_mesh_vertex_inner(const SubdivForeachContext *foreach_context,
+                                     void *tls_v,
+                                     const int ptex_face_index,
+                                     const float u,
+                                     const float v,
+                                     const int coarse_poly_index,
+                                     const int coarse_corner,
+                                     const int subdiv_vertex_index)
+{
+  SubdivMeshContext *ctx = static_cast(foreach_context->user_data);
+  SubdivMeshTLS *tls = static_cast(tls_v);
+  Subdiv *subdiv = ctx->subdiv;
+  const MPoly *coarse_poly = &ctx->coarse_polys[coarse_poly_index];
+  Mesh *subdiv_mesh = ctx->subdiv_mesh;
+  MVert *subdiv_vert = &ctx->subdiv_verts[subdiv_vertex_index];
+  subdiv_mesh_ensure_vertex_interpolation(ctx, tls, coarse_poly, coarse_corner);
+  subdiv_vertex_data_interpolate(ctx, subdiv_vert, &tls->vertex_interpolation, u, v);
+  BKE_subdiv_eval_final_point(subdiv, ptex_face_index, u, v, subdiv_vert->co);
+  subdiv_mesh_tag_center_vertex(coarse_poly, subdiv_vertex_index, u, v, subdiv_mesh);
+  subdiv_vertex_orco_evaluate(ctx, ptex_face_index, u, v, subdiv_vertex_index);
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Edge subdivision process
+ * \{ */
+
+static void subdiv_copy_edge_data(SubdivMeshContext *ctx,
+                                  MEdge *subdiv_edge,
+                                  const MEdge *coarse_edge)
+{
+  const int subdiv_edge_index = subdiv_edge - ctx->subdiv_edges;
+  if (coarse_edge == nullptr) {
+    subdiv_edge->crease = 0;
+    subdiv_edge->flag = 0;
+    if (!ctx->settings->use_optimal_display) {
+      subdiv_edge->flag |= ME_EDGERENDER;
+    }
+    if (ctx->edge_origindex != nullptr) {
+      ctx->edge_origindex[subdiv_edge_index] = ORIGINDEX_NONE;
+    }
+    return;
+  }
+  const int coarse_edge_index = coarse_edge - ctx->coarse_edges;
+  CustomData_copy_data(
+      &ctx->coarse_mesh->edata, &ctx->subdiv_mesh->edata, coarse_edge_index, subdiv_edge_index, 1);
+  subdiv_edge->flag |= ME_EDGERENDER;
+}
+
+static void subdiv_mesh_edge(const SubdivForeachContext *foreach_context,
+                             void *UNUSED(tls),
+                             const int coarse_edge_index,
+                             const int subdiv_edge_index,
+                             const bool UNUSED(is_loose),
+                             const int subdiv_v1,
+                             const int subdiv_v2)
+{
+  SubdivMeshContext *ctx = static_cast(foreach_context->user_data);
+  MEdge *subdiv_medge = ctx->subdiv_edges;
+  MEdge *subdiv_edge = &subdiv_medge[subdiv_edge_index];
+  const MEdge *coarse_edge = nullptr;
+  if (coarse_edge_index != ORIGINDEX_NONE) {
+    const MEdge *coarse_medge = ctx->coarse_edges;
+    coarse_edge = &coarse_medge[coarse_edge_index];
+  }
+  subdiv_copy_edge_data(ctx, subdiv_edge, coarse_edge);
+  subdiv_edge->v1 = subdiv_v1;
+  subdiv_edge->v2 = subdiv_v2;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Loops creation/interpolation
+ * \{ */
+
+static void subdiv_interpolate_loop_data(const SubdivMeshContext *ctx,
+                                         MLoop *subdiv_loop,
+                                         const LoopsForInterpolation *loop_interpolation,
+                                         const float u,
+                                         const float v)
+{
+  const int subdiv_loop_index = subdiv_loop - ctx->subdiv_loops;
+  const float weights[4] = {(1.0f - u) * (1.0f - v), u * (1.0f - v), u * v, (1.0f - u) * v};
+  CustomData_interp(loop_interpolation->loop_data,
+                    &ctx->subdiv_mesh->ldata,
+                    loop_interpolation->loop_indices,
+                    weights,
+                    nullptr,
+                    4,
+                    subdiv_loop_index);
+  /* TODO(sergey): Set ORIGINDEX. */
+}
+
+static void subdiv_eval_uv_layer(SubdivMeshContext *ctx,
+                                 MLoop *subdiv_loop,
+                                 const int ptex_face_index,
+                                 const float u,
+                                 const float v)
+{
+  if (ctx->num_uv_layers == 0) {
+    return;
+  }
+  Subdiv *subdiv = ctx->subdiv;
+  const int mloop_index = subdiv_loop - ctx->subdiv_loops;
+  for (int layer_index = 0; layer_index < ctx->num_uv_layers; layer_index++) {
+    MLoopUV *subdiv_loopuv = &ctx->uv_layers[layer_index][mloop_index];
+    BKE_subdiv_eval_face_varying(subdiv, layer_index, ptex_face_index, u, v, subdiv_loopuv->uv);
+  }
+}
+
+static void subdiv_mesh_ensure_loop_interpolation(SubdivMeshContext *ctx,
+                                                  SubdivMeshTLS *tls,
+                                                  const MPoly *coarse_poly,
+                                                  const int coarse_corner)
+{
+  /* Check whether we've moved to another corner or polygon. */
+  if (tls->loop_interpolation_initialized) {
+    if (tls->loop_interpolation_coarse_poly != coarse_poly ||
+        tls->loop_interpolation_coarse_corner != coarse_corner) {
+      loop_interpolation_end(&tls->loop_interpolation);
+      tls->loop_interpolation_initialized = false;
+    }
+  }
+  /* Initialize the interpolation. */
+  if (!tls->loop_interpolation_initialized) {
+    loop_interpolation_init(ctx, &tls->loop_interpolation, coarse_poly);
+  }
+  /* Update it for a new corner if needed. */
+  if (!tls->loop_interpolation_initialized ||
+      tls->loop_interpolation_coarse_corner != coarse_corner) {
+    loop_interpolation_from_corner(ctx, &tls->loop_interpolation, coarse_poly, coarse_corner);
+  }
+  /* Store settings used for the current state of interpolator. */
+  tls->loop_interpolation_initialized = true;
+  tls->loop_interpolation_coarse_poly = coarse_poly;
+  tls->loop_interpolation_coarse_corner = coarse_corner;
+}
+
+static void subdiv_mesh_loop(const SubdivForeachContext *foreach_context,
+                             void *tls_v,
+                             const int ptex_face_index,
+                             const float u,
+                             const float v,
+                             const int UNUSED(coarse_loop_index),
+                             const int coarse_poly_index,
+                             const int coarse_corner,
+                             const int subdiv_loop_index,
+                             const int subdiv_vertex_index,
+                             const int subdiv_edge_index)
+{
+  SubdivMeshContext *ctx = static_cast(foreach_context->user_data);
+  SubdivMeshTLS *tls = static_cast(tls_v);
+  const MPoly *coarse_mpoly = ctx->coarse_polys;
+  const MPoly *coarse_poly = &coarse_mpoly[coarse_poly_index];
+  MLoop *subdiv_loop = &ctx->subdiv_loops[subdiv_loop_index];
+  subdiv_mesh_ensure_loop_interpolation(ctx, tls, coarse_poly, coarse_corner);
+  subdiv_interpolate_loop_data(ctx, subdiv_loop, &tls->loop_interpolation, u, v);
+  subdiv_eval_uv_layer(ctx, subdiv_loop, ptex_face_index, u, v);
+  subdiv_loop->v = subdiv_vertex_index;
+  subdiv_loop->e = subdiv_edge_index;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Polygons subdivision process
+ * \{ */
+
+static void subdiv_copy_poly_data(const SubdivMeshContext *ctx,
+                                  MPoly *subdiv_poly,
+                                  const MPoly *coarse_poly)
+{
+  const int coarse_poly_index = coarse_poly - ctx->coarse_polys;
+  const int subdiv_poly_index = subdiv_poly - ctx->subdiv_polys;
+  CustomData_copy_data(
+      &ctx->coarse_mesh->pdata, &ctx->subdiv_mesh->pdata, coarse_poly_index, subdiv_poly_index, 1);
+}
+
+static void subdiv_mesh_poly(const SubdivForeachContext *foreach_context,
+                             void *UNUSED(tls),
+                             const int coarse_poly_index,
+                             const int subdiv_poly_index,
+                             const int start_loop_index,
+                             const int num_loops)
+{
+  BLI_assert(coarse_poly_index != ORIGINDEX_NONE);
+  SubdivMeshContext *ctx = static_cast(foreach_context->user_data);
+  const MPoly *coarse_poly = &ctx->coarse_polys[coarse_poly_index];
+  MPoly *subdiv_poly = &ctx->subdiv_polys[subdiv_poly_index];
+  subdiv_copy_poly_data(ctx, subdiv_poly, coarse_poly);
+  subdiv_poly->loopstart = start_loop_index;
+  subdiv_poly->totloop = num_loops;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Loose elements subdivision process
+ * \{ */
+
+static void subdiv_mesh_vertex_loose(const SubdivForeachContext *foreach_context,
+                                     void *UNUSED(tls),
+                                     const int coarse_vertex_index,
+                                     const int subdiv_vertex_index)
+{
+  SubdivMeshContext *ctx = static_cast(foreach_context->user_data);
+  const MVert *coarse_vertex = &ctx->coarse_verts[coarse_vertex_index];
+  MVert *subdiv_vertex = &ctx->subdiv_verts[subdiv_vertex_index];
+  subdiv_vertex_data_copy(ctx, coarse_vertex, subdiv_vertex);
+}
+
+/* Get neighbor edges of the given one.
+ * - neighbors[0] is an edge adjacent to edge->v1.
+ * - neighbors[1] is an edge adjacent to edge->v2. */
+static void find_edge_neighbors(const MEdge *coarse_edges,
+                                const MeshElemMap *vert_to_edge_map,
+                                const int edge_index,
+                                const MEdge *neighbors[2])
+{
+  const MEdge *edge = &coarse_edges[edge_index];
+  neighbors[0] = nullptr;
+  neighbors[1] = nullptr;
+  int neighbor_counters[2] = {0, 0};
+  for (const int i : Span(vert_to_edge_map[edge->v1].indices, vert_to_edge_map[edge->v1].count)) {
+    if (i == edge_index) {
+      continue;
+    }
+    if (ELEM(edge->v1, coarse_edges[i].v1, coarse_edges[i].v2)) {
+      neighbors[0] = &coarse_edges[i];
+      ++neighbor_counters[0];
+    }
+  }
+  for (const int i : Span(vert_to_edge_map[edge->v2].indices, vert_to_edge_map[edge->v2].count)) {
+    if (i == edge_index) {
+      continue;
+    }
+    if (ELEM(edge->v2, coarse_edges[i].v1, coarse_edges[i].v2)) {
+      neighbors[1] = &coarse_edges[i];
+      ++neighbor_counters[1];
+    }
+  }
+  /* Vertices which has more than one neighbor are considered infinitely
+   * sharp. This is also how topology factory treats vertices of a surface
+   * which are adjacent to a loose edge. */
+  if (neighbor_counters[0] > 1) {
+    neighbors[0] = nullptr;
+  }
+  if (neighbor_counters[1] > 1) {
+    neighbors[1] = nullptr;
+  }
+}
+
+static void points_for_loose_edges_interpolation_get(const MVert *coarse_mvert,
+                                                     const MEdge *coarse_edge,
+                                                     const MEdge *neighbors[2],
+                                                     float points_r[4][3])
+{
+  /* Middle points corresponds to the edge. */
+  copy_v3_v3(points_r[1], coarse_mvert[coarse_edge->v1].co);
+  copy_v3_v3(points_r[2], coarse_mvert[coarse_edge->v2].co);
+  /* Start point, duplicate from edge start if no neighbor. */
+  if (neighbors[0] != nullptr) {
+    if (neighbors[0]->v1 == coarse_edge->v1) {
+      copy_v3_v3(points_r[0], coarse_mvert[neighbors[0]->v2].co);
+    }
+    else {
+      copy_v3_v3(points_r[0], coarse_mvert[neighbors[0]->v1].co);
+    }
+  }
+  else {
+    sub_v3_v3v3(points_r[0], points_r[1], points_r[2]);
+    add_v3_v3(points_r[0], points_r[1]);
+  }
+  /* End point, duplicate from edge end if no neighbor. */
+  if (neighbors[1] != nullptr) {
+    if (neighbors[1]->v1 == coarse_edge->v2) {
+      copy_v3_v3(points_r[3], coarse_mvert[neighbors[1]->v2].co);
+    }
+    else {
+      copy_v3_v3(points_r[3], coarse_mvert[neighbors[1]->v1].co);
+    }
+  }
+  else {
+    sub_v3_v3v3(points_r[3], points_r[2], points_r[1]);
+    add_v3_v3(points_r[3], points_r[2]);
+  }
+}
+
+void BKE_subdiv_mesh_interpolate_position_on_edge(const MVert *coarse_verts,
+                                                  const MEdge *coarse_edges,
+                                                  const MeshElemMap *vert_to_edge_map,
+                                                  const int coarse_edge_index,
+                                                  const bool is_simple,
+                                                  const float u,
+                                                  float pos_r[3])
+{
+  const MEdge *coarse_edge = &coarse_edges[coarse_edge_index];
+  if (is_simple) {
+    const MVert *vert_1 = &coarse_verts[coarse_edge->v1];
+    const MVert *vert_2 = &coarse_verts[coarse_edge->v2];
+    interp_v3_v3v3(pos_r, vert_1->co, vert_2->co, u);
+  }
+  else {
+    /* Find neighbors of the coarse edge. */
+    const MEdge *neighbors[2];
+    find_edge_neighbors(coarse_edges, vert_to_edge_map, coarse_edge_index, neighbors);
+    float points[4][3];
+    points_for_loose_edges_interpolation_get(coarse_verts, coarse_edge, neighbors, points);
+    float weights[4];
+    key_curve_position_weights(u, weights, KEY_BSPLINE);
+    interp_v3_v3v3v3v3(pos_r, points[0], points[1], points[2], points[3], weights);
+  }
+}
+
+static void subdiv_mesh_vertex_of_loose_edge_interpolate(SubdivMeshContext *ctx,
+                                                         const MEdge *coarse_edge,
+                                                         const float u,
+                                                         const int subdiv_vertex_index)
+{
+  const Mesh *coarse_mesh = ctx->coarse_mesh;
+  Mesh *subdiv_mesh = ctx->subdiv_mesh;
+  /* This is never used for end-points (which are copied from the original). */
+  BLI_assert(u > 0.0f);
+  BLI_assert(u < 1.0f);
+  const float interpolation_weights[2] = {1.0f - u, u};
+  const int coarse_vertex_indices[2] = {static_cast(coarse_edge->v1),
+                                        static_cast(coarse_edge->v2)};
+  CustomData_interp(&coarse_mesh->vdata,
+                    &subdiv_mesh->vdata,
+                    coarse_vertex_indices,
+                    interpolation_weights,
+                    nullptr,
+                    2,
+                    subdiv_vertex_index);
+  if (ctx->vert_origindex != nullptr) {
+    ctx->vert_origindex[subdiv_vertex_index] = ORIGINDEX_NONE;
+  }
+}
+
+static void subdiv_mesh_vertex_of_loose_edge(const SubdivForeachContext *foreach_context,
+                                             void *UNUSED(tls),
+                                             const int coarse_edge_index,
+                                             const float u,
+                                             const int subdiv_vertex_index)
+{
+  SubdivMeshContext *ctx = static_cast(foreach_context->user_data);
+  const Mesh *coarse_mesh = ctx->coarse_mesh;
+  const MEdge *coarse_edge = &ctx->coarse_edges[coarse_edge_index];
+  const bool is_simple = ctx->subdiv->settings.is_simple;
+
+  /* Lazily initialize a vertex to edge map to avoid quadratic runtime when subdividing loose
+   * edges. Do this here to avoid the cost in common cases when there are no loose edges at all. */
+  if (ctx->vert_to_edge_map == NULL) {
+    std::lock_guard lock{ctx->vert_to_edge_map_mutex};
+    if (ctx->vert_to_edge_map == NULL) {
+      BKE_mesh_vert_edge_map_create(&ctx->vert_to_edge_map,
+                                    &ctx->vert_to_edge_buffer,
+                                    ctx->coarse_edges,
+                                    coarse_mesh->totvert,
+                                    ctx->coarse_mesh->totedge);
+    }
+  }
+
+  /* Interpolate custom data when not an end point.
+   * This data has already been copied from the original vertex by #subdiv_mesh_vertex_loose. */
+  if (!ELEM(u, 0.0, 1.0)) {
+    subdiv_mesh_vertex_of_loose_edge_interpolate(ctx, coarse_edge, u, subdiv_vertex_index);
+  }
+  /* Interpolate coordinate. */
+  MVert *subdiv_vertex = &ctx->subdiv_verts[subdiv_vertex_index];
+  BKE_subdiv_mesh_interpolate_position_on_edge(ctx->coarse_verts,
+                                               ctx->coarse_edges,
+                                               ctx->vert_to_edge_map,
+                                               coarse_edge_index,
+                                               is_simple,
+                                               u,
+                                               subdiv_vertex->co);
+  /* Reset flags and such. */
+  subdiv_vertex->flag = 0;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Initialization
+ * \{ */
+
+static void setup_foreach_callbacks(const SubdivMeshContext *subdiv_context,
+                                    SubdivForeachContext *foreach_context)
+{
+  memset(foreach_context, 0, sizeof(*foreach_context));
+  /* General information. */
+  foreach_context->topology_info = subdiv_mesh_topology_info;
+  /* Every boundary geometry. Used for displacement averaging. */
+  if (subdiv_context->have_displacement) {
+    foreach_context->vertex_every_corner = subdiv_mesh_vertex_displacement_every_corner;
+    foreach_context->vertex_every_edge = subdiv_mesh_vertex_displacement_every_edge;
+  }
+  foreach_context->vertex_corner = subdiv_mesh_vertex_corner;
+  foreach_context->vertex_edge = subdiv_mesh_vertex_edge;
+  foreach_context->vertex_inner = subdiv_mesh_vertex_inner;
+  foreach_context->edge = subdiv_mesh_edge;
+  foreach_context->loop = subdiv_mesh_loop;
+  foreach_context->poly = subdiv_mesh_poly;
+  foreach_context->vertex_loose = subdiv_mesh_vertex_loose;
+  foreach_context->vertex_of_loose_edge = subdiv_mesh_vertex_of_loose_edge;
+  foreach_context->user_data_tls_free = subdiv_mesh_tls_free;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Public entry point
+ * \{ */
+
+Mesh *BKE_subdiv_to_mesh(Subdiv *subdiv,
+                         const SubdivToMeshSettings *settings,
+                         const Mesh *coarse_mesh)
+{
+  BKE_subdiv_stats_begin(&subdiv->stats, SUBDIV_STATS_SUBDIV_TO_MESH);
+  /* Make sure evaluator is up to date with possible new topology, and that
+   * it is refined for the new positions of coarse vertices. */
+  if (!BKE_subdiv_eval_begin_from_mesh(
+          subdiv, coarse_mesh, nullptr, SUBDIV_EVALUATOR_TYPE_CPU, nullptr)) {
+    /* This could happen in two situations:
+     * - OpenSubdiv is disabled.
+     * - Something totally bad happened, and OpenSubdiv rejected our
+     *   topology.
+     * In either way, we can't safely continue. */
+    if (coarse_mesh->totpoly) {
+      BKE_subdiv_stats_end(&subdiv->stats, SUBDIV_STATS_SUBDIV_TO_MESH);
+      return nullptr;
+    }
+  }
+  /* Initialize subdivision mesh creation context. */
+  SubdivMeshContext subdiv_context = {0};
+  subdiv_context.settings = settings;
+
+  subdiv_context.coarse_mesh = coarse_mesh;
+  subdiv_context.coarse_verts = BKE_mesh_verts(coarse_mesh);
+  subdiv_context.coarse_edges = BKE_mesh_edges(coarse_mesh);
+  subdiv_context.coarse_polys = BKE_mesh_polys(coarse_mesh);
+  subdiv_context.coarse_loops = BKE_mesh_loops(coarse_mesh);
+
+  subdiv_context.subdiv = subdiv;
+  subdiv_context.have_displacement = (subdiv->displacement_evaluator != nullptr);
+  /* Multi-threaded traversal/evaluation. */
+  BKE_subdiv_stats_begin(&subdiv->stats, SUBDIV_STATS_SUBDIV_TO_MESH_GEOMETRY);
+  SubdivForeachContext foreach_context;
+  setup_foreach_callbacks(&subdiv_context, &foreach_context);
+  SubdivMeshTLS tls = {0};
+  foreach_context.user_data = &subdiv_context;
+  foreach_context.user_data_tls_size = sizeof(SubdivMeshTLS);
+  foreach_context.user_data_tls = &tls;
+  BKE_subdiv_foreach_subdiv_geometry(subdiv, &foreach_context, settings, coarse_mesh);
+  BKE_subdiv_stats_end(&subdiv->stats, SUBDIV_STATS_SUBDIV_TO_MESH_GEOMETRY);
+  Mesh *result = subdiv_context.subdiv_mesh;
+  // BKE_mesh_validate(result, true, true);
+  BKE_subdiv_stats_end(&subdiv->stats, SUBDIV_STATS_SUBDIV_TO_MESH);
+  /* Using normals from the limit surface gives different results than Blender's vertex normal
+   * calculation. Since vertex normals are supposed to be a consistent cache, don't bother
+   * calculating them here. The work may have been pointless anyway if the mesh is deformed or
+   * changed afterwards. */
+  BLI_assert(BKE_mesh_vertex_normals_are_dirty(result) || BKE_mesh_poly_normals_are_dirty(result));
+  /* Free used memory. */
+  subdiv_mesh_context_free(&subdiv_context);
+  return result;
+}
+
+/** \} */
diff --git a/source/blender/blenkernel/intern/subdiv_modifier.c b/source/blender/blenkernel/intern/subdiv_modifier.c
index 57af0192d59..2271fd90bda 100644
--- a/source/blender/blenkernel/intern/subdiv_modifier.c
+++ b/source/blender/blenkernel/intern/subdiv_modifier.c
@@ -98,11 +98,6 @@ static bool is_subdivision_evaluation_possible_on_gpu(void)
     return false;
   }
 
-  const int available_evaluators = openSubdiv_getAvailableEvaluators();
-  if ((available_evaluators & OPENSUBDIV_EVALUATOR_GLSL_COMPUTE) == 0) {
-    return false;
-  }
-
   return true;
 }
 
diff --git a/source/blender/blenkernel/intern/subsurf_ccg.c b/source/blender/blenkernel/intern/subsurf_ccg.c
index efabb4f039a..0e5f9f30243 100644
--- a/source/blender/blenkernel/intern/subsurf_ccg.c
+++ b/source/blender/blenkernel/intern/subsurf_ccg.c
@@ -284,7 +284,8 @@ static int ss_sync_from_uv(CCGSubSurf *ss,
    * UV map in really simple cases with mirror + subsurf, see second part of T44530.
    * Also, initially intention is to treat merged vertices from mirror modifier as seams.
    * This fixes a very old regression (2.49 was correct here) */
-  vmap = BKE_mesh_uv_vert_map_create(mpoly, mloop, mloopuv, totface, totvert, limit, false, true);
+  vmap = BKE_mesh_uv_vert_map_create(
+      mpoly, NULL, mloop, mloopuv, totface, totvert, limit, false, true);
   if (!vmap) {
     return 0;
   }
@@ -878,7 +879,7 @@ static void ccgDM_getFinalVertNo(DerivedMesh *dm, int vertNum, float r_no[3])
 BLI_INLINE void ccgDM_to_MVert(MVert *mv, const CCGKey *key, CCGElem *elem)
 {
   copy_v3_v3(mv->co, CCG_elem_co(key, elem));
-  mv->flag = mv->bweight = 0;
+  mv->flag = 0;
 }
 
 static void ccgDM_copyFinalVertArray(DerivedMesh *dm, MVert *mvert)
@@ -948,7 +949,7 @@ BLI_INLINE void ccgDM_to_MEdge(MEdge *med, const int v1, const int v2, const sho
 {
   med->v1 = v1;
   med->v2 = v2;
-  med->crease = med->bweight = 0;
+  med->crease = 0;
   med->flag = flag;
 }
 
@@ -1133,14 +1134,12 @@ static void ccgDM_copyFinalPolyArray(DerivedMesh *dm, MPoly *mpoly)
     CCGFace *f = ccgdm->faceMap[index].face;
     int x, y, S, numVerts = ccgSubSurf_getFaceNumVerts(f);
     int flag = (faceFlags) ? faceFlags[index].flag : ME_SMOOTH;
-    int mat_nr = (faceFlags) ? faceFlags[index].mat_nr : 0;
 
     for (S = 0; S < numVerts; S++) {
       for (y = 0; y < gridSize - 1; y++) {
         for (x = 0; x < gridSize - 1; x++) {
           MPoly *mp = &mpoly[i];
 
-          mp->mat_nr = mat_nr;
           mp->flag = flag;
           mp->loopstart = k;
           mp->totloop = 4;
@@ -1247,7 +1246,7 @@ static void *ccgDM_get_vert_data_layer(DerivedMesh *dm, int type)
     BLI_rw_mutex_lock(&ccgdm->origindex_cache_rwlock, THREAD_LOCK_WRITE);
 
     origindex = CustomData_add_layer(
-        &dm->vertData, CD_ORIGINDEX, CD_CALLOC, NULL, dm->numVertData);
+        &dm->vertData, CD_ORIGINDEX, CD_SET_DEFAULT, NULL, dm->numVertData);
 
     totorig = ccgSubSurf_getNumVerts(ss);
     totnone = dm->numVertData - totorig;
@@ -1286,7 +1285,7 @@ static void *ccgDM_get_edge_data_layer(DerivedMesh *dm, int type)
     }
 
     origindex = CustomData_add_layer(
-        &dm->edgeData, CD_ORIGINDEX, CD_CALLOC, NULL, dm->numEdgeData);
+        &dm->edgeData, CD_ORIGINDEX, CD_SET_DEFAULT, NULL, dm->numEdgeData);
 
     totedge = ccgSubSurf_getNumEdges(ss);
     totorig = totedge * (edgeSize - 1);
@@ -1329,7 +1328,7 @@ static void *ccgDM_get_poly_data_layer(DerivedMesh *dm, int type)
     }
 
     origindex = CustomData_add_layer(
-        &dm->polyData, CD_ORIGINDEX, CD_CALLOC, NULL, dm->numPolyData);
+        &dm->polyData, CD_ORIGINDEX, CD_SET_DEFAULT, NULL, dm->numPolyData);
 
     totface = ccgSubSurf_getNumFaces(ss);
 
@@ -1599,13 +1598,15 @@ static void set_ccgdm_all_geometry(CCGDerivedMesh *ccgdm,
   gridSize = ccgSubSurf_getGridSize(ss);
   gridFaces = gridSize - 1;
   gridCuts = gridSize - 2;
-  /*gridInternalVerts = gridSideVerts * gridSideVerts; - as yet, unused */
+  // gridInternalVerts = gridSideVerts * gridSideVerts; /* As yet, unused. */
   gridSideEdges = gridSize - 1;
   gridInternalEdges = (gridSideEdges - 1) * gridSideEdges * 2;
 
   medge = dm->getEdgeArray(dm);
 
   const MPoly *mpoly = CustomData_get_layer(&dm->polyData, CD_MPOLY);
+  const int *material_indices = CustomData_get_layer_named(
+      &dm->polyData, CD_MPOLY, "material_index");
   const int *base_polyOrigIndex = CustomData_get_layer(&dm->polyData, CD_ORIGINDEX);
 
   int *vertOrigIndex = DM_get_vert_data_layer(&ccgdm->dm, CD_ORIGINDEX);
@@ -1634,7 +1635,7 @@ static void set_ccgdm_all_geometry(CCGDerivedMesh *ccgdm,
     ccgdm->faceMap[index].startFace = faceNum;
 
     faceFlags->flag = mpoly ? mpoly[origIndex].flag : 0;
-    faceFlags->mat_nr = mpoly ? mpoly[origIndex].mat_nr : 0;
+    faceFlags->mat_nr = material_indices ? material_indices[origIndex] : 0;
     faceFlags++;
 
     /* set the face base vert */
diff --git a/source/blender/blenkernel/intern/text.c b/source/blender/blenkernel/intern/text.c
index 9acf387b930..1444ba1e1c4 100644
--- a/source/blender/blenkernel/intern/text.c
+++ b/source/blender/blenkernel/intern/text.c
@@ -245,7 +245,7 @@ IDTypeInfo IDType_ID_TXT = {
     .foreach_id = NULL,
     .foreach_cache = NULL,
     .foreach_path = text_foreach_path,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = text_blend_write,
     .blend_read_data = text_blend_read_data,
diff --git a/source/blender/blenkernel/intern/texture.c b/source/blender/blenkernel/intern/texture.c
index d9e5887a9a8..5cdaa12f514 100644
--- a/source/blender/blenkernel/intern/texture.c
+++ b/source/blender/blenkernel/intern/texture.c
@@ -96,6 +96,7 @@ static void texture_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const i
       BKE_id_copy_ex(
           bmain, (ID *)texture_src->nodetree, (ID **)&texture_dst->nodetree, flag_private_id_data);
     }
+    texture_dst->nodetree->owner_id = &texture_dst->id;
   }
 
   if ((flag & LIB_ID_COPY_NO_PREVIEW) == 0) {
@@ -206,7 +207,7 @@ IDTypeInfo IDType_ID_TE = {
     .foreach_id = texture_foreach_id,
     .foreach_cache = NULL,
     .foreach_path = NULL,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = texture_blend_write,
     .blend_read_data = texture_blend_read_data,
diff --git a/source/blender/blenkernel/intern/tracking_detect.c b/source/blender/blenkernel/intern/tracking_detect.c
index 51ffce4a3e3..540f880905d 100644
--- a/source/blender/blenkernel/intern/tracking_detect.c
+++ b/source/blender/blenkernel/intern/tracking_detect.c
@@ -81,7 +81,6 @@ static void detect_retrieve_libmv_features(MovieTracking *tracking,
 
   a = libmv_countFeatures(features);
   while (a--) {
-    MovieTrackingTrack *track;
     double x, y, size, score;
     bool ok = true;
     float xu, yu;
@@ -99,7 +98,8 @@ static void detect_retrieve_libmv_features(MovieTracking *tracking,
     }
 
     if (ok) {
-      track = BKE_tracking_track_add(tracking, tracksbase, xu, yu, framenr, width, height);
+      MovieTrackingTrack *track = BKE_tracking_track_add(
+          tracking, tracksbase, xu, yu, framenr, width, height);
       track->flag |= SELECT;
       track->pat_flag |= SELECT;
       track->search_flag |= SELECT;
diff --git a/source/blender/blenkernel/intern/tracking_stabilize.c b/source/blender/blenkernel/intern/tracking_stabilize.c
index e2e0b4227e3..b03d226964c 100644
--- a/source/blender/blenkernel/intern/tracking_stabilize.c
+++ b/source/blender/blenkernel/intern/tracking_stabilize.c
@@ -1342,7 +1342,7 @@ ImBuf *BKE_tracking_stabilize_frame(
     return ibuf;
   }
 
-  /* Allocate frame for stabilization result, copy alpha mode and colorspace. */
+  /* Allocate frame for stabilization result, copy alpha mode and color-space. */
   ibuf_flags = 0;
   if (ibuf->rect) {
     ibuf_flags |= IB_rect;
diff --git a/source/blender/blenkernel/intern/type_conversions.cc b/source/blender/blenkernel/intern/type_conversions.cc
index 0b5d6ad7b10..a01f5d19088 100644
--- a/source/blender/blenkernel/intern/type_conversions.cc
+++ b/source/blender/blenkernel/intern/type_conversions.cc
@@ -367,20 +367,38 @@ void DataTypeConversions::convert_to_uninitialized(const CPPType &from_type,
   functions->convert_single_to_uninitialized(from_value, to_value);
 }
 
+static void call_convert_to_uninitialized_fn(const GVArray &from,
+                                             const fn::MultiFunction &fn,
+                                             const IndexMask mask,
+                                             GMutableSpan to)
+{
+  fn::MFParamsBuilder params{fn, from.size()};
+  params.add_readonly_single_input(from);
+  params.add_uninitialized_single_output(to);
+  fn::MFContextBuilder context;
+  fn.call_auto(mask, params, context);
+}
+
+static void call_convert_to_uninitialized_fn(const GVArray &from,
+                                             const fn::MultiFunction &fn,
+                                             GMutableSpan to)
+{
+  call_convert_to_uninitialized_fn(from, fn, IndexMask(from.size()), to);
+}
+
 void DataTypeConversions::convert_to_initialized_n(GSpan from_span, GMutableSpan to_span) const
 {
   const CPPType &from_type = from_span.type();
   const CPPType &to_type = to_span.type();
+
   BLI_assert(from_span.size() == to_span.size());
   BLI_assert(this->is_convertible(from_type, to_type));
+
   const fn::MultiFunction *fn = this->get_conversion_multi_function(
       MFDataType::ForSingle(from_type), MFDataType::ForSingle(to_type));
-  fn::MFParamsBuilder params{*fn, from_span.size()};
-  params.add_readonly_single_input(from_span);
+
   to_type.destruct_n(to_span.data(), to_span.size());
-  params.add_uninitialized_single_output(to_span);
-  fn::MFContextBuilder context;
-  fn->call_auto(IndexRange(from_span.size()), params, context);
+  call_convert_to_uninitialized_fn(GVArray::ForSpan(from_span), *fn, to_span);
 }
 
 class GVArray_For_ConvertedGVArray : public GVArrayImpl {
@@ -414,6 +432,20 @@ class GVArray_For_ConvertedGVArray : public GVArrayImpl {
     old_to_new_conversions_.convert_single_to_uninitialized(buffer, r_value);
     from_type_.destruct(buffer);
   }
+
+  void materialize(const IndexMask mask, void *dst) const override
+  {
+    type_->destruct_n(dst, mask.min_array_size());
+    this->materialize_to_uninitialized(mask, dst);
+  }
+
+  void materialize_to_uninitialized(const IndexMask mask, void *dst) const override
+  {
+    call_convert_to_uninitialized_fn(varray_,
+                                     *old_to_new_conversions_.multi_function,
+                                     mask,
+                                     {this->type(), dst, mask.min_array_size()});
+  }
 };
 
 class GVMutableArray_For_ConvertedGVMutableArray : public GVMutableArrayImpl {
@@ -458,6 +490,20 @@ class GVMutableArray_For_ConvertedGVMutableArray : public GVMutableArrayImpl {
     new_to_old_conversions_.convert_single_to_uninitialized(value, buffer);
     varray_.set_by_relocate(index, buffer);
   }
+
+  void materialize(const IndexMask mask, void *dst) const override
+  {
+    type_->destruct_n(dst, mask.min_array_size());
+    this->materialize_to_uninitialized(mask, dst);
+  }
+
+  void materialize_to_uninitialized(const IndexMask mask, void *dst) const override
+  {
+    call_convert_to_uninitialized_fn(varray_,
+                                     *old_to_new_conversions_.multi_function,
+                                     mask,
+                                     {this->type(), dst, mask.min_array_size()});
+  }
 };
 
 GVArray DataTypeConversions::try_convert(GVArray varray, const CPPType &to_type) const
@@ -495,9 +541,8 @@ fn::GField DataTypeConversions::try_convert(fn::GField field, const CPPType &to_
   if (!this->is_convertible(from_type, to_type)) {
     return {};
   }
-  const fn::MultiFunction &fn =
-      *bke::get_implicit_type_conversions().get_conversion_multi_function(
-          fn::MFDataType::ForSingle(from_type), fn::MFDataType::ForSingle(to_type));
+  const fn::MultiFunction &fn = *this->get_conversion_multi_function(
+      fn::MFDataType::ForSingle(from_type), fn::MFDataType::ForSingle(to_type));
   return {std::make_shared(fn, Vector{std::move(field)})};
 }
 
diff --git a/source/blender/blenkernel/intern/unit.c b/source/blender/blenkernel/intern/unit.c
index b31632f0234..f7ea4c81fbf 100644
--- a/source/blender/blenkernel/intern/unit.c
+++ b/source/blender/blenkernel/intern/unit.c
@@ -845,8 +845,8 @@ static bool unit_distribute_negatives(char *str, const int len_max)
   bool changed = false;
 
   char *remaining_str = str;
-  int remaining_str_len = len_max;
   while ((remaining_str = find_next_negative(str, remaining_str)) != NULL) {
+    int remaining_str_len;
     /* Exit early in the unlikely situation that we've run out of length to add the parentheses. */
     remaining_str_len = len_max - (int)(remaining_str - str);
     if (remaining_str_len <= 2) {
@@ -1025,6 +1025,16 @@ static bool unit_find(const char *str, const bUnitDef *unit)
   return false;
 }
 
+static const bUnitDef *unit_find_in_collection(const bUnitCollection *usys, const char *str)
+{
+  for (const bUnitDef *unit = usys->units; unit->name; unit++) {
+    if (unit_find(str, unit)) {
+      return unit;
+    }
+  }
+  return NULL;
+}
+
 /**
  * Try to find a default unit from current or previous string.
  * This allows us to handle cases like 2 + 2mm, people would expect to get 4mm, not 2.002m!
@@ -1035,25 +1045,15 @@ static const bUnitDef *unit_detect_from_str(const bUnitCollection *usys,
                                             const char *str,
                                             const char *str_prev)
 {
-  const bUnitDef *unit = NULL;
-
   /* See which units the new value has. */
-  for (unit = usys->units; unit->name; unit++) {
-    if (unit_find(str, unit)) {
-      break;
-    }
-  }
+  const bUnitDef *unit = unit_find_in_collection(usys, str);
   /* Else, try to infer the default unit from the previous string. */
-  if (str_prev && (unit == NULL || unit->name == NULL)) {
+  if (str_prev && (unit == NULL)) {
     /* See which units the original value had. */
-    for (unit = usys->units; unit->name; unit++) {
-      if (unit_find(str_prev, unit)) {
-        break;
-      }
-    }
+    unit = unit_find_in_collection(usys, str_prev);
   }
   /* Else, fall back to default unit. */
-  if (unit == NULL || unit->name == NULL) {
+  if (unit == NULL) {
     unit = unit_default(usys);
   }
 
@@ -1067,11 +1067,8 @@ bool BKE_unit_string_contains_unit(const char *str, int type)
     if (!is_valid_unit_collection(usys)) {
       continue;
     }
-
-    for (int i = 0; i < usys->length; i++) {
-      if (unit_find(str, usys->units + i)) {
-        return true;
-      }
+    if (unit_find_in_collection(usys, str)) {
+      return true;
     }
   }
   return false;
@@ -1155,13 +1152,12 @@ bool BKE_unit_replace_string(
    */
   {
     char *str_found = str;
-    const char *ch = str;
 
     while ((str_found = strchr(str_found, SEP_CHR))) {
       bool op_found = false;
 
       /* Any operators after this? */
-      for (ch = str_found + 1; *ch != '\0'; ch++) {
+      for (const char *ch = str_found + 1; *ch != '\0'; ch++) {
         if (ELEM(*ch, ' ', '\t')) {
           continue;
         }
diff --git a/source/blender/blenkernel/intern/vfont.c b/source/blender/blenkernel/intern/vfont.c
index 9a6f861eae8..ddc758c6887 100644
--- a/source/blender/blenkernel/intern/vfont.c
+++ b/source/blender/blenkernel/intern/vfont.c
@@ -81,7 +81,7 @@ static void vfont_copy_data(Main *UNUSED(bmain),
 {
   VFont *vfont_dst = (VFont *)id_dst;
 
-  /* We never handle usercount here for own data. */
+  /* We never handle user-count here for own data. */
   const int flag_subdata = flag | LIB_ID_CREATE_NO_USER_REFCOUNT;
 
   /* Just to be sure, should not have any value actually after reading time. */
@@ -171,7 +171,7 @@ IDTypeInfo IDType_ID_VF = {
     .foreach_id = NULL,
     .foreach_cache = NULL,
     .foreach_path = vfont_foreach_path,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = vfont_blend_write,
     .blend_read_data = vfont_blend_read_data,
@@ -1422,7 +1422,8 @@ static bool vfont_to_curve(Object *ob,
     for (i = 0; i <= selend; i++, ct++) {
       if (i >= selstart) {
         selboxes[i - selstart].x = ct->xof * font_size;
-        selboxes[i - selstart].y = ct->yof * font_size;
+        selboxes[i - selstart].y = (ct->yof - 0.25f) * font_size;
+        selboxes[i - selstart].h = font_size;
       }
     }
   }
@@ -1481,17 +1482,17 @@ static bool vfont_to_curve(Object *ob,
 
     f = ef->textcurs[0];
 
-    f[0] = font_size * (-0.1f * co + ct->xof);
-    f[1] = font_size * (0.1f * si + ct->yof);
+    f[0] = font_size * (-0.02f * co + ct->xof);
+    f[1] = font_size * (0.1f * si - (0.25f * co) + ct->yof);
 
-    f[2] = font_size * (0.1f * co + ct->xof);
-    f[3] = font_size * (-0.1f * si + ct->yof);
+    f[2] = font_size * (0.02f * co + ct->xof);
+    f[3] = font_size * (-0.1f * si - (0.25f * co) + ct->yof);
 
-    f[4] = font_size * (0.1f * co + 0.8f * si + ct->xof);
-    f[5] = font_size * (-0.1f * si + 0.8f * co + ct->yof);
+    f[4] = font_size * (0.02f * co + 0.8f * si + ct->xof);
+    f[5] = font_size * (-0.1f * si + 0.75f * co + ct->yof);
 
-    f[6] = font_size * (-0.1f * co + 0.8f * si + ct->xof);
-    f[7] = font_size * (0.1f * si + 0.8f * co + ct->yof);
+    f[6] = font_size * (-0.02f * co + 0.8f * si + ct->xof);
+    f[7] = font_size * (0.1f * si + 0.75f * co + ct->yof);
   }
 
   if (mode == FO_SELCHANGE) {
diff --git a/source/blender/blenkernel/intern/volume.cc b/source/blender/blenkernel/intern/volume.cc
index 82405830437..502d3ac6d40 100644
--- a/source/blender/blenkernel/intern/volume.cc
+++ b/source/blender/blenkernel/intern/volume.cc
@@ -661,7 +661,7 @@ IDTypeInfo IDType_ID_VO = {
     /* foreach_id */ volume_foreach_id,
     /* foreach_cache */ volume_foreach_cache,
     /* foreach_path */ volume_foreach_path,
-    /* owner_get */ nullptr,
+    /* owner_pointer_get */ nullptr,
 
     /* blend_write */ volume_blend_write,
     /* blend_read_data */ volume_blend_read_data,
@@ -1089,6 +1089,8 @@ static void volume_evaluate_modifiers(struct Depsgraph *depsgraph,
   ModifierApplyFlag apply_flag = use_render ? MOD_APPLY_RENDER : MOD_APPLY_USECACHE;
   const ModifierEvalContext mectx = {depsgraph, object, apply_flag};
 
+  BKE_modifiers_clear_errors(object);
+
   /* Get effective list of modifiers to execute. Some effects like shape keys
    * are added as virtual modifiers before the user created modifiers. */
   VirtualModifierData virtualModifierData;
@@ -1359,6 +1361,26 @@ const char *BKE_volume_grid_name(const VolumeGrid *volume_grid)
 }
 
 #ifdef WITH_OPENVDB
+struct ClearGridOp {
+  openvdb::GridBase &grid;
+
+  template void operator()()
+  {
+    static_cast(grid).clear();
+  }
+};
+void BKE_volume_grid_clear_tree(openvdb::GridBase &grid)
+{
+  const VolumeGridType grid_type = BKE_volume_grid_type_openvdb(grid);
+  ClearGridOp op{grid};
+  BKE_volume_grid_type_operation(grid_type, op);
+}
+void BKE_volume_grid_clear_tree(Volume &volume, VolumeGrid &volume_grid)
+{
+  openvdb::GridBase::Ptr grid = BKE_volume_grid_openvdb_for_write(&volume, &volume_grid, false);
+  BKE_volume_grid_clear_tree(*grid);
+}
+
 VolumeGridType BKE_volume_grid_type_openvdb(const openvdb::GridBase &grid)
 {
   if (grid.isType()) {
@@ -1449,6 +1471,23 @@ void BKE_volume_grid_transform_matrix(const VolumeGrid *volume_grid, float mat[4
 #endif
 }
 
+void BKE_volume_grid_transform_matrix_set(struct VolumeGrid *volume_grid, const float mat[4][4])
+{
+#ifdef WITH_OPENVDB
+  openvdb::math::Mat4f mat_openvdb;
+  for (int col = 0; col < 4; col++) {
+    for (int row = 0; row < 4; row++) {
+      mat_openvdb(col, row) = mat[col][row];
+    }
+  }
+  openvdb::GridBase::Ptr grid = volume_grid->grid();
+  grid->setTransform(std::make_shared(
+      std::make_shared(mat_openvdb)));
+#else
+  UNUSED_VARS(volume_grid, mat);
+#endif
+}
+
 /* Grid Tree and Voxels */
 
 /* Volume Editing */
@@ -1545,6 +1584,17 @@ void BKE_volume_grid_remove(Volume *volume, VolumeGrid *grid)
 #endif
 }
 
+bool BKE_volume_grid_determinant_valid(const double determinant)
+{
+#ifdef WITH_OPENVDB
+  /* Limit taken from openvdb/math/Maps.h. */
+  return std::abs(determinant) >= 3.0 * openvdb::math::Tolerance::value();
+#else
+  UNUSED_VARS(determinant);
+  return true;
+#endif
+}
+
 int BKE_volume_simplify_level(const Depsgraph *depsgraph)
 {
   if (DEG_get_mode(depsgraph) != DAG_EVAL_RENDER) {
diff --git a/source/blender/blenkernel/intern/volume_to_mesh.cc b/source/blender/blenkernel/intern/volume_to_mesh.cc
index ef75d3d2482..f3bb8726b4f 100644
--- a/source/blender/blenkernel/intern/volume_to_mesh.cc
+++ b/source/blender/blenkernel/intern/volume_to_mesh.cc
@@ -178,9 +178,9 @@ Mesh *volume_to_mesh(const openvdb::GridBase &grid,
                               0,
                               0,
                               0,
-                              {mesh->mvert, mesh->totvert},
-                              {mesh->mpoly, mesh->totpoly},
-                              {mesh->mloop, mesh->totloop});
+                              mesh->verts_for_write(),
+                              mesh->polys_for_write(),
+                              mesh->loops_for_write());
 
   BKE_mesh_calc_edges(mesh, false, false);
 
diff --git a/source/blender/blenkernel/intern/workspace.c b/source/blender/blenkernel/intern/workspace.c
deleted file mode 100644
index 0265dd037b1..00000000000
--- a/source/blender/blenkernel/intern/workspace.c
+++ /dev/null
@@ -1,596 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-
-/** \file
- * \ingroup bke
- */
-
-#include 
-#include 
-#include 
-
-#include "BLI_listbase.h"
-#include "BLI_string.h"
-#include "BLI_string_utils.h"
-#include "BLI_utildefines.h"
-
-#include "BLT_translation.h"
-
-#include "BKE_asset.h"
-#include "BKE_global.h"
-#include "BKE_idprop.h"
-#include "BKE_idtype.h"
-#include "BKE_lib_id.h"
-#include "BKE_lib_query.h"
-#include "BKE_main.h"
-#include "BKE_object.h"
-#include "BKE_scene.h"
-#include "BKE_workspace.h"
-
-#include "DNA_object_types.h"
-#include "DNA_scene_types.h"
-#include "DNA_screen_types.h"
-#include "DNA_windowmanager_types.h"
-#include "DNA_workspace_types.h"
-
-#include "DEG_depsgraph.h"
-
-#include "MEM_guardedalloc.h"
-
-#include "BLO_read_write.h"
-
-/* -------------------------------------------------------------------- */
-
-static void workspace_init_data(ID *id)
-{
-  WorkSpace *workspace = (WorkSpace *)id;
-
-  BKE_asset_library_reference_init_default(&workspace->asset_library_ref);
-}
-
-static void workspace_free_data(ID *id)
-{
-  WorkSpace *workspace = (WorkSpace *)id;
-
-  BKE_workspace_relations_free(&workspace->hook_layout_relations);
-
-  BLI_freelistN(&workspace->owner_ids);
-  BLI_freelistN(&workspace->layouts);
-
-  while (!BLI_listbase_is_empty(&workspace->tools)) {
-    BKE_workspace_tool_remove(workspace, workspace->tools.first);
-  }
-
-  MEM_SAFE_FREE(workspace->status_text);
-}
-
-static void workspace_foreach_id(ID *id, LibraryForeachIDData *data)
-{
-  WorkSpace *workspace = (WorkSpace *)id;
-
-  BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, workspace->pin_scene, IDWALK_CB_NOP);
-
-  LISTBASE_FOREACH (WorkSpaceLayout *, layout, &workspace->layouts) {
-    BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, layout->screen, IDWALK_CB_USER);
-  }
-}
-
-static void workspace_blend_write(BlendWriter *writer, ID *id, const void *id_address)
-{
-  WorkSpace *workspace = (WorkSpace *)id;
-
-  BLO_write_id_struct(writer, WorkSpace, id_address, &workspace->id);
-  BKE_id_blend_write(writer, &workspace->id);
-  BLO_write_struct_list(writer, WorkSpaceLayout, &workspace->layouts);
-  BLO_write_struct_list(writer, WorkSpaceDataRelation, &workspace->hook_layout_relations);
-  BLO_write_struct_list(writer, wmOwnerID, &workspace->owner_ids);
-  BLO_write_struct_list(writer, bToolRef, &workspace->tools);
-  LISTBASE_FOREACH (bToolRef *, tref, &workspace->tools) {
-    if (tref->properties) {
-      IDP_BlendWrite(writer, tref->properties);
-    }
-  }
-}
-
-static void workspace_blend_read_data(BlendDataReader *reader, ID *id)
-{
-  WorkSpace *workspace = (WorkSpace *)id;
-
-  BLO_read_list(reader, &workspace->layouts);
-  BLO_read_list(reader, &workspace->hook_layout_relations);
-  BLO_read_list(reader, &workspace->owner_ids);
-  BLO_read_list(reader, &workspace->tools);
-
-  LISTBASE_FOREACH (WorkSpaceDataRelation *, relation, &workspace->hook_layout_relations) {
-    /* Parent pointer does not belong to workspace data and is therefore restored in lib_link step
-     * of window manager. */
-    BLO_read_data_address(reader, &relation->value);
-  }
-
-  LISTBASE_FOREACH (bToolRef *, tref, &workspace->tools) {
-    tref->runtime = NULL;
-    BLO_read_data_address(reader, &tref->properties);
-    IDP_BlendDataRead(reader, &tref->properties);
-  }
-
-  workspace->status_text = NULL;
-
-  id_us_ensure_real(&workspace->id);
-}
-
-static void workspace_blend_read_lib(BlendLibReader *reader, ID *id)
-{
-  WorkSpace *workspace = (WorkSpace *)id;
-  Main *bmain = BLO_read_lib_get_main(reader);
-
-  /* Do not keep the scene reference when appending a workspace. Setting a scene for a workspace is
-   * a convenience feature, but the workspace should never truly depend on scene data. */
-  if (ID_IS_LINKED(id)) {
-    workspace->pin_scene = NULL;
-  }
-  else {
-    BLO_read_id_address(reader, NULL, &workspace->pin_scene);
-  }
-
-  /* Restore proper 'parent' pointers to relevant data, and clean up unused/invalid entries. */
-  LISTBASE_FOREACH_MUTABLE (WorkSpaceDataRelation *, relation, &workspace->hook_layout_relations) {
-    relation->parent = NULL;
-    LISTBASE_FOREACH (wmWindowManager *, wm, &bmain->wm) {
-      LISTBASE_FOREACH (wmWindow *, win, &wm->windows) {
-        if (win->winid == relation->parentid) {
-          relation->parent = win->workspace_hook;
-        }
-      }
-    }
-    if (relation->parent == NULL) {
-      BLI_freelinkN(&workspace->hook_layout_relations, relation);
-    }
-  }
-
-  LISTBASE_FOREACH_MUTABLE (WorkSpaceLayout *, layout, &workspace->layouts) {
-    BLO_read_id_address(reader, id->lib, &layout->screen);
-
-    if (layout->screen) {
-      if (ID_IS_LINKED(id)) {
-        layout->screen->winid = 0;
-        if (layout->screen->temp) {
-          /* delete temp layouts when appending */
-          BKE_workspace_layout_remove(bmain, workspace, layout);
-        }
-      }
-    }
-    else {
-      /* If we're reading a layout without screen stored, it's useless and we shouldn't keep it
-       * around. */
-      BKE_workspace_layout_remove(bmain, workspace, layout);
-    }
-  }
-}
-
-static void workspace_blend_read_expand(BlendExpander *expander, ID *id)
-{
-  WorkSpace *workspace = (WorkSpace *)id;
-
-  LISTBASE_FOREACH (WorkSpaceLayout *, layout, &workspace->layouts) {
-    BLO_expand(expander, BKE_workspace_layout_screen_get(layout));
-  }
-}
-
-IDTypeInfo IDType_ID_WS = {
-    .id_code = ID_WS,
-    .id_filter = FILTER_ID_WS,
-    .main_listbase_index = INDEX_ID_WS,
-    .struct_size = sizeof(WorkSpace),
-    .name = "WorkSpace",
-    .name_plural = "workspaces",
-    .translation_context = BLT_I18NCONTEXT_ID_WORKSPACE,
-    .flags = IDTYPE_FLAGS_NO_COPY | IDTYPE_FLAGS_ONLY_APPEND | IDTYPE_FLAGS_NO_ANIMDATA,
-    .asset_type_info = NULL,
-
-    .init_data = workspace_init_data,
-    .copy_data = NULL,
-    .free_data = workspace_free_data,
-    .make_local = NULL,
-    .foreach_id = workspace_foreach_id,
-    .foreach_cache = NULL,
-    .foreach_path = NULL,
-    .owner_get = NULL,
-
-    .blend_write = workspace_blend_write,
-    .blend_read_data = workspace_blend_read_data,
-    .blend_read_lib = workspace_blend_read_lib,
-    .blend_read_expand = workspace_blend_read_expand,
-
-    .blend_read_undo_preserve = NULL,
-
-    .lib_override_apply_post = NULL,
-};
-
-/* -------------------------------------------------------------------- */
-/** \name Internal Utils
- * \{ */
-
-static void workspace_layout_name_set(WorkSpace *workspace,
-                                      WorkSpaceLayout *layout,
-                                      const char *new_name)
-{
-  BLI_strncpy(layout->name, new_name, sizeof(layout->name));
-  BLI_uniquename(&workspace->layouts,
-                 layout,
-                 "Layout",
-                 '.',
-                 offsetof(WorkSpaceLayout, name),
-                 sizeof(layout->name));
-}
-
-/**
- * This should only be used directly when it is to be expected that there isn't
- * a layout within \a workspace that wraps \a screen. Usually - especially outside
- * of BKE_workspace - #BKE_workspace_layout_find should be used!
- */
-static WorkSpaceLayout *workspace_layout_find_exec(const WorkSpace *workspace,
-                                                   const bScreen *screen)
-{
-  return BLI_findptr(&workspace->layouts, screen, offsetof(WorkSpaceLayout, screen));
-}
-
-static void workspace_relation_add(ListBase *relation_list,
-                                   void *parent,
-                                   const int parentid,
-                                   void *data)
-{
-  WorkSpaceDataRelation *relation = MEM_callocN(sizeof(*relation), __func__);
-  relation->parent = parent;
-  relation->parentid = parentid;
-  relation->value = data;
-  /* add to head, if we switch back to it soon we find it faster. */
-  BLI_addhead(relation_list, relation);
-}
-static void workspace_relation_remove(ListBase *relation_list, WorkSpaceDataRelation *relation)
-{
-  BLI_remlink(relation_list, relation);
-  MEM_freeN(relation);
-}
-
-static void workspace_relation_ensure_updated(ListBase *relation_list,
-                                              void *parent,
-                                              const int parentid,
-                                              void *data)
-{
-  WorkSpaceDataRelation *relation = BLI_listbase_bytes_find(
-      relation_list, &parentid, sizeof(parentid), offsetof(WorkSpaceDataRelation, parentid));
-  if (relation != NULL) {
-    relation->parent = parent;
-    relation->value = data;
-    /* reinsert at the head of the list, so that more commonly used relations are found faster. */
-    BLI_remlink(relation_list, relation);
-    BLI_addhead(relation_list, relation);
-  }
-  else {
-    /* no matching relation found, add new one */
-    workspace_relation_add(relation_list, parent, parentid, data);
-  }
-}
-
-static void *workspace_relation_get_data_matching_parent(const ListBase *relation_list,
-                                                         const void *parent)
-{
-  WorkSpaceDataRelation *relation = BLI_findptr(
-      relation_list, parent, offsetof(WorkSpaceDataRelation, parent));
-  if (relation != NULL) {
-    return relation->value;
-  }
-
-  return NULL;
-}
-
-/**
- * Checks if \a screen is already used within any workspace. A screen should never be assigned to
- * multiple WorkSpaceLayouts, but that should be ensured outside of the BKE_workspace module
- * and without such checks.
- * Hence, this should only be used as assert check before assigning a screen to a workspace.
- */
-#ifndef NDEBUG
-static bool workspaces_is_screen_used
-#else
-static bool UNUSED_FUNCTION(workspaces_is_screen_used)
-#endif
-    (const Main *bmain, bScreen *screen)
-{
-  for (WorkSpace *workspace = bmain->workspaces.first; workspace; workspace = workspace->id.next) {
-    if (workspace_layout_find_exec(workspace, screen)) {
-      return true;
-    }
-  }
-
-  return false;
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Create, Delete, Init
- * \{ */
-
-WorkSpace *BKE_workspace_add(Main *bmain, const char *name)
-{
-  WorkSpace *new_workspace = BKE_id_new(bmain, ID_WS, name);
-  id_us_ensure_real(&new_workspace->id);
-  return new_workspace;
-}
-
-void BKE_workspace_remove(Main *bmain, WorkSpace *workspace)
-{
-  for (WorkSpaceLayout *layout = workspace->layouts.first, *layout_next; layout;
-       layout = layout_next) {
-    layout_next = layout->next;
-    BKE_workspace_layout_remove(bmain, workspace, layout);
-  }
-  BKE_id_free(bmain, workspace);
-}
-
-WorkSpaceInstanceHook *BKE_workspace_instance_hook_create(const Main *bmain, const int winid)
-{
-  WorkSpaceInstanceHook *hook = MEM_callocN(sizeof(WorkSpaceInstanceHook), __func__);
-
-  /* set an active screen-layout for each possible window/workspace combination */
-  for (WorkSpace *workspace = bmain->workspaces.first; workspace; workspace = workspace->id.next) {
-    BKE_workspace_active_layout_set(hook, winid, workspace, workspace->layouts.first);
-  }
-
-  return hook;
-}
-void BKE_workspace_instance_hook_free(const Main *bmain, WorkSpaceInstanceHook *hook)
-{
-  /* workspaces should never be freed before wm (during which we call this function).
-   * However, when running in background mode, loading a blend file may allocate windows (that need
-   * to be freed) without creating workspaces. This happens in BlendfileLoadingBaseTest. */
-  BLI_assert(!BLI_listbase_is_empty(&bmain->workspaces) || G.background);
-
-  /* Free relations for this hook */
-  for (WorkSpace *workspace = bmain->workspaces.first; workspace; workspace = workspace->id.next) {
-    for (WorkSpaceDataRelation *relation = workspace->hook_layout_relations.first, *relation_next;
-         relation;
-         relation = relation_next) {
-      relation_next = relation->next;
-      if (relation->parent == hook) {
-        workspace_relation_remove(&workspace->hook_layout_relations, relation);
-      }
-    }
-  }
-
-  MEM_freeN(hook);
-}
-
-WorkSpaceLayout *BKE_workspace_layout_add(Main *bmain,
-                                          WorkSpace *workspace,
-                                          bScreen *screen,
-                                          const char *name)
-{
-  WorkSpaceLayout *layout = MEM_callocN(sizeof(*layout), __func__);
-
-  BLI_assert(!workspaces_is_screen_used(bmain, screen));
-#ifndef DEBUG
-  UNUSED_VARS(bmain);
-#endif
-  layout->screen = screen;
-  id_us_plus(&layout->screen->id);
-  workspace_layout_name_set(workspace, layout, name);
-  BLI_addtail(&workspace->layouts, layout);
-
-  return layout;
-}
-
-void BKE_workspace_layout_remove(Main *bmain, WorkSpace *workspace, WorkSpaceLayout *layout)
-{
-  /* Screen should usually be set, but we call this from file reading to get rid of invalid
-   * layouts. */
-  if (layout->screen) {
-    id_us_min(&layout->screen->id);
-    BKE_id_free(bmain, layout->screen);
-  }
-  BLI_freelinkN(&workspace->layouts, layout);
-}
-
-void BKE_workspace_relations_free(ListBase *relation_list)
-{
-  for (WorkSpaceDataRelation *relation = relation_list->first, *relation_next; relation;
-       relation = relation_next) {
-    relation_next = relation->next;
-    workspace_relation_remove(relation_list, relation);
-  }
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name General Utils
- * \{ */
-
-WorkSpaceLayout *BKE_workspace_layout_find(const WorkSpace *workspace, const bScreen *screen)
-{
-  WorkSpaceLayout *layout = workspace_layout_find_exec(workspace, screen);
-  if (layout) {
-    return layout;
-  }
-
-  printf(
-      "%s: Couldn't find layout in this workspace: '%s' screen: '%s'. "
-      "This should not happen!\n",
-      __func__,
-      workspace->id.name + 2,
-      screen->id.name + 2);
-
-  return NULL;
-}
-
-WorkSpaceLayout *BKE_workspace_layout_find_global(const Main *bmain,
-                                                  const bScreen *screen,
-                                                  WorkSpace **r_workspace)
-{
-  WorkSpaceLayout *layout;
-
-  if (r_workspace) {
-    *r_workspace = NULL;
-  }
-
-  for (WorkSpace *workspace = bmain->workspaces.first; workspace; workspace = workspace->id.next) {
-    if ((layout = workspace_layout_find_exec(workspace, screen))) {
-      if (r_workspace) {
-        *r_workspace = workspace;
-      }
-
-      return layout;
-    }
-  }
-
-  return NULL;
-}
-
-WorkSpaceLayout *BKE_workspace_layout_iter_circular(const WorkSpace *workspace,
-                                                    WorkSpaceLayout *start,
-                                                    bool (*callback)(const WorkSpaceLayout *layout,
-                                                                     void *arg),
-                                                    void *arg,
-                                                    const bool iter_backward)
-{
-  WorkSpaceLayout *iter_layout;
-
-  if (iter_backward) {
-    LISTBASE_CIRCULAR_BACKWARD_BEGIN (&workspace->layouts, iter_layout, start) {
-      if (!callback(iter_layout, arg)) {
-        return iter_layout;
-      }
-    }
-    LISTBASE_CIRCULAR_BACKWARD_END(&workspace->layouts, iter_layout, start);
-  }
-  else {
-    LISTBASE_CIRCULAR_FORWARD_BEGIN (&workspace->layouts, iter_layout, start) {
-      if (!callback(iter_layout, arg)) {
-        return iter_layout;
-      }
-    }
-    LISTBASE_CIRCULAR_FORWARD_END(&workspace->layouts, iter_layout, start);
-  }
-
-  return NULL;
-}
-
-void BKE_workspace_tool_remove(struct WorkSpace *workspace, struct bToolRef *tref)
-{
-  if (tref->runtime) {
-    MEM_freeN(tref->runtime);
-  }
-  if (tref->properties) {
-    IDP_FreeProperty(tref->properties);
-  }
-  BLI_remlink(&workspace->tools, tref);
-  MEM_freeN(tref);
-}
-
-bool BKE_workspace_owner_id_check(const WorkSpace *workspace, const char *owner_id)
-{
-  if ((*owner_id == '\0') || ((workspace->flags & WORKSPACE_USE_FILTER_BY_ORIGIN) == 0)) {
-    return true;
-  }
-
-  /* We could use hash lookup, for now this list is highly likely under < ~16 items. */
-  return BLI_findstring(&workspace->owner_ids, owner_id, offsetof(wmOwnerID, name)) != NULL;
-}
-
-void BKE_workspace_id_tag_all_visible(Main *bmain, int tag)
-{
-  BKE_main_id_tag_listbase(&bmain->workspaces, tag, false);
-  wmWindowManager *wm = bmain->wm.first;
-  LISTBASE_FOREACH (wmWindow *, win, &wm->windows) {
-    WorkSpace *workspace = BKE_workspace_active_get(win->workspace_hook);
-    workspace->id.tag |= tag;
-  }
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Getters/Setters
- * \{ */
-
-WorkSpace *BKE_workspace_active_get(WorkSpaceInstanceHook *hook)
-{
-  return hook->active;
-}
-void BKE_workspace_active_set(WorkSpaceInstanceHook *hook, WorkSpace *workspace)
-{
-  /* DO NOT check for `hook->active == workspace` here. Caller code is supposed to do it if
-   * that optimization is possible and needed.
-   * This code can be called from places where we might have this equality, but still want to
-   * ensure/update the active layout below.
-   * Known case where this is buggy and will crash later due to NULL active layout: reading
-   * a blend file, when the new read workspace ID happens to have the exact same memory address
-   * as when it was saved in the blend file (extremely unlikely, but possible). */
-
-  hook->active = workspace;
-  if (workspace) {
-    WorkSpaceLayout *layout = workspace_relation_get_data_matching_parent(
-        &workspace->hook_layout_relations, hook);
-    if (layout) {
-      hook->act_layout = layout;
-    }
-  }
-}
-
-WorkSpaceLayout *BKE_workspace_active_layout_get(const WorkSpaceInstanceHook *hook)
-{
-  return hook->act_layout;
-}
-
-WorkSpaceLayout *BKE_workspace_active_layout_for_workspace_get(const WorkSpaceInstanceHook *hook,
-                                                               const WorkSpace *workspace)
-{
-  /* If the workspace is active, the active layout can be returned, no need for a lookup. */
-  if (hook->active == workspace) {
-    return hook->act_layout;
-  }
-
-  /* Inactive workspace */
-  return workspace_relation_get_data_matching_parent(&workspace->hook_layout_relations, hook);
-}
-
-void BKE_workspace_active_layout_set(WorkSpaceInstanceHook *hook,
-                                     const int winid,
-                                     WorkSpace *workspace,
-                                     WorkSpaceLayout *layout)
-{
-  hook->act_layout = layout;
-  workspace_relation_ensure_updated(&workspace->hook_layout_relations, hook, winid, layout);
-}
-
-bScreen *BKE_workspace_active_screen_get(const WorkSpaceInstanceHook *hook)
-{
-  return hook->act_layout->screen;
-}
-void BKE_workspace_active_screen_set(WorkSpaceInstanceHook *hook,
-                                     const int winid,
-                                     WorkSpace *workspace,
-                                     bScreen *screen)
-{
-  /* we need to find the WorkspaceLayout that wraps this screen */
-  WorkSpaceLayout *layout = BKE_workspace_layout_find(hook->active, screen);
-  BKE_workspace_active_layout_set(hook, winid, workspace, layout);
-}
-
-const char *BKE_workspace_layout_name_get(const WorkSpaceLayout *layout)
-{
-  return layout->name;
-}
-void BKE_workspace_layout_name_set(WorkSpace *workspace,
-                                   WorkSpaceLayout *layout,
-                                   const char *new_name)
-{
-  workspace_layout_name_set(workspace, layout, new_name);
-}
-
-bScreen *BKE_workspace_layout_screen_get(const WorkSpaceLayout *layout)
-{
-  return layout->screen;
-}
-
-/** \} */
diff --git a/source/blender/blenkernel/intern/workspace.cc b/source/blender/blenkernel/intern/workspace.cc
new file mode 100644
index 00000000000..8008dacc853
--- /dev/null
+++ b/source/blender/blenkernel/intern/workspace.cc
@@ -0,0 +1,610 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/** \file
+ * \ingroup bke
+ */
+
+#include 
+#include 
+#include 
+
+#include "BLI_listbase.h"
+#include "BLI_string.h"
+#include "BLI_string_utils.h"
+#include "BLI_utildefines.h"
+
+#include "BLT_translation.h"
+
+#include "BKE_asset.h"
+#include "BKE_global.h"
+#include "BKE_idprop.h"
+#include "BKE_idtype.h"
+#include "BKE_lib_id.h"
+#include "BKE_lib_query.h"
+#include "BKE_main.h"
+#include "BKE_object.h"
+#include "BKE_scene.h"
+#include "BKE_workspace.h"
+
+#include "DNA_object_types.h"
+#include "DNA_scene_types.h"
+#include "DNA_screen_types.h"
+#include "DNA_windowmanager_types.h"
+#include "DNA_workspace_types.h"
+
+#include "DEG_depsgraph.h"
+
+#include "MEM_guardedalloc.h"
+
+#include "BLO_read_write.h"
+
+/* -------------------------------------------------------------------- */
+
+static void workspace_init_data(ID *id)
+{
+  WorkSpace *workspace = (WorkSpace *)id;
+
+  BKE_asset_library_reference_init_default(&workspace->asset_library_ref);
+}
+
+static void workspace_free_data(ID *id)
+{
+  WorkSpace *workspace = (WorkSpace *)id;
+
+  BKE_workspace_relations_free(&workspace->hook_layout_relations);
+
+  BLI_freelistN(&workspace->owner_ids);
+  BLI_freelistN(&workspace->layouts);
+
+  while (!BLI_listbase_is_empty(&workspace->tools)) {
+    BKE_workspace_tool_remove(workspace, static_cast(workspace->tools.first));
+  }
+
+  MEM_SAFE_FREE(workspace->status_text);
+}
+
+static void workspace_foreach_id(ID *id, LibraryForeachIDData *data)
+{
+  WorkSpace *workspace = (WorkSpace *)id;
+
+  BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, workspace->pin_scene, IDWALK_CB_NOP);
+
+  LISTBASE_FOREACH (WorkSpaceLayout *, layout, &workspace->layouts) {
+    BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, layout->screen, IDWALK_CB_USER);
+  }
+}
+
+static void workspace_blend_write(BlendWriter *writer, ID *id, const void *id_address)
+{
+  WorkSpace *workspace = (WorkSpace *)id;
+
+  BLO_write_id_struct(writer, WorkSpace, id_address, &workspace->id);
+  BKE_id_blend_write(writer, &workspace->id);
+  BLO_write_struct_list(writer, WorkSpaceLayout, &workspace->layouts);
+  BLO_write_struct_list(writer, WorkSpaceDataRelation, &workspace->hook_layout_relations);
+  BLO_write_struct_list(writer, wmOwnerID, &workspace->owner_ids);
+  BLO_write_struct_list(writer, bToolRef, &workspace->tools);
+  LISTBASE_FOREACH (bToolRef *, tref, &workspace->tools) {
+    if (tref->properties) {
+      IDP_BlendWrite(writer, tref->properties);
+    }
+  }
+}
+
+static void workspace_blend_read_data(BlendDataReader *reader, ID *id)
+{
+  WorkSpace *workspace = (WorkSpace *)id;
+
+  BLO_read_list(reader, &workspace->layouts);
+  BLO_read_list(reader, &workspace->hook_layout_relations);
+  BLO_read_list(reader, &workspace->owner_ids);
+  BLO_read_list(reader, &workspace->tools);
+
+  LISTBASE_FOREACH (WorkSpaceDataRelation *, relation, &workspace->hook_layout_relations) {
+    /* Parent pointer does not belong to workspace data and is therefore restored in lib_link step
+     * of window manager. */
+    BLO_read_data_address(reader, &relation->value);
+  }
+
+  LISTBASE_FOREACH (bToolRef *, tref, &workspace->tools) {
+    tref->runtime = nullptr;
+    BLO_read_data_address(reader, &tref->properties);
+    IDP_BlendDataRead(reader, &tref->properties);
+  }
+
+  workspace->status_text = nullptr;
+
+  id_us_ensure_real(&workspace->id);
+}
+
+static void workspace_blend_read_lib(BlendLibReader *reader, ID *id)
+{
+  WorkSpace *workspace = (WorkSpace *)id;
+  Main *bmain = BLO_read_lib_get_main(reader);
+
+  /* Do not keep the scene reference when appending a workspace. Setting a scene for a workspace is
+   * a convenience feature, but the workspace should never truly depend on scene data. */
+  if (ID_IS_LINKED(id)) {
+    workspace->pin_scene = nullptr;
+  }
+  else {
+    BLO_read_id_address(reader, nullptr, &workspace->pin_scene);
+  }
+
+  /* Restore proper 'parent' pointers to relevant data, and clean up unused/invalid entries. */
+  LISTBASE_FOREACH_MUTABLE (WorkSpaceDataRelation *, relation, &workspace->hook_layout_relations) {
+    relation->parent = nullptr;
+    LISTBASE_FOREACH (wmWindowManager *, wm, &bmain->wm) {
+      LISTBASE_FOREACH (wmWindow *, win, &wm->windows) {
+        if (win->winid == relation->parentid) {
+          relation->parent = win->workspace_hook;
+        }
+      }
+    }
+    if (relation->parent == nullptr) {
+      BLI_freelinkN(&workspace->hook_layout_relations, relation);
+    }
+  }
+
+  LISTBASE_FOREACH_MUTABLE (WorkSpaceLayout *, layout, &workspace->layouts) {
+    BLO_read_id_address(reader, id->lib, &layout->screen);
+
+    if (layout->screen) {
+      if (ID_IS_LINKED(id)) {
+        layout->screen->winid = 0;
+        if (layout->screen->temp) {
+          /* delete temp layouts when appending */
+          BKE_workspace_layout_remove(bmain, workspace, layout);
+        }
+      }
+    }
+    else {
+      /* If we're reading a layout without screen stored, it's useless and we shouldn't keep it
+       * around. */
+      BKE_workspace_layout_remove(bmain, workspace, layout);
+    }
+  }
+}
+
+static void workspace_blend_read_expand(BlendExpander *expander, ID *id)
+{
+  WorkSpace *workspace = (WorkSpace *)id;
+
+  LISTBASE_FOREACH (WorkSpaceLayout *, layout, &workspace->layouts) {
+    BLO_expand(expander, BKE_workspace_layout_screen_get(layout));
+  }
+}
+
+IDTypeInfo IDType_ID_WS = {
+    /* id_code */ ID_WS,
+    /* id_filter */ FILTER_ID_WS,
+    /* main_listbase_index */ INDEX_ID_WS,
+    /* struct_size */ sizeof(WorkSpace),
+    /* name */ "WorkSpace",
+    /* name_plural */ "workspaces",
+    /* translation_context */ BLT_I18NCONTEXT_ID_WORKSPACE,
+    /* flags */ IDTYPE_FLAGS_NO_COPY | IDTYPE_FLAGS_ONLY_APPEND | IDTYPE_FLAGS_NO_ANIMDATA,
+    /* asset_type_info */ nullptr,
+
+    /* init_data */ workspace_init_data,
+    /* copy_data */ nullptr,
+    /* free_data */ workspace_free_data,
+    /* make_local */ nullptr,
+    /* foreach_id */ workspace_foreach_id,
+    /* foreach_cache */ nullptr,
+    /* foreach_path */ nullptr,
+    /* owner_pointer_get */ nullptr,
+
+    /* blend_write */ workspace_blend_write,
+    /* blend_read_data */ workspace_blend_read_data,
+    /* blend_read_lib */ workspace_blend_read_lib,
+    /* blend_read_expand */ workspace_blend_read_expand,
+
+    /* blend_read_undo_preserve */ nullptr,
+
+    /* lib_override_apply_post */ nullptr,
+};
+
+/* -------------------------------------------------------------------- */
+/** \name Internal Utils
+ * \{ */
+
+static void workspace_layout_name_set(WorkSpace *workspace,
+                                      WorkSpaceLayout *layout,
+                                      const char *new_name)
+{
+  BLI_strncpy(layout->name, new_name, sizeof(layout->name));
+  BLI_uniquename(&workspace->layouts,
+                 layout,
+                 "Layout",
+                 '.',
+                 offsetof(WorkSpaceLayout, name),
+                 sizeof(layout->name));
+}
+
+/**
+ * This should only be used directly when it is to be expected that there isn't
+ * a layout within \a workspace that wraps \a screen. Usually - especially outside
+ * of BKE_workspace - #BKE_workspace_layout_find should be used!
+ */
+static WorkSpaceLayout *workspace_layout_find_exec(const WorkSpace *workspace,
+                                                   const bScreen *screen)
+{
+  return static_cast(
+      BLI_findptr(&workspace->layouts, screen, offsetof(WorkSpaceLayout, screen)));
+}
+
+static void workspace_relation_add(ListBase *relation_list,
+                                   void *parent,
+                                   const int parentid,
+                                   void *data)
+{
+  WorkSpaceDataRelation *relation = MEM_cnew(__func__);
+  relation->parent = parent;
+  relation->parentid = parentid;
+  relation->value = data;
+  /* add to head, if we switch back to it soon we find it faster. */
+  BLI_addhead(relation_list, relation);
+}
+static void workspace_relation_remove(ListBase *relation_list, WorkSpaceDataRelation *relation)
+{
+  BLI_remlink(relation_list, relation);
+  MEM_freeN(relation);
+}
+
+static void workspace_relation_ensure_updated(ListBase *relation_list,
+                                              void *parent,
+                                              const int parentid,
+                                              void *data)
+{
+  WorkSpaceDataRelation *relation = static_cast(BLI_listbase_bytes_find(
+      relation_list, &parentid, sizeof(parentid), offsetof(WorkSpaceDataRelation, parentid)));
+  if (relation != nullptr) {
+    relation->parent = parent;
+    relation->value = data;
+    /* reinsert at the head of the list, so that more commonly used relations are found faster. */
+    BLI_remlink(relation_list, relation);
+    BLI_addhead(relation_list, relation);
+  }
+  else {
+    /* no matching relation found, add new one */
+    workspace_relation_add(relation_list, parent, parentid, data);
+  }
+}
+
+static void *workspace_relation_get_data_matching_parent(const ListBase *relation_list,
+                                                         const void *parent)
+{
+  WorkSpaceDataRelation *relation = static_cast(
+      BLI_findptr(relation_list, parent, offsetof(WorkSpaceDataRelation, parent)));
+  if (relation != nullptr) {
+    return relation->value;
+  }
+
+  return nullptr;
+}
+
+/**
+ * Checks if \a screen is already used within any workspace. A screen should never be assigned to
+ * multiple WorkSpaceLayouts, but that should be ensured outside of the BKE_workspace module
+ * and without such checks.
+ * Hence, this should only be used as assert check before assigning a screen to a workspace.
+ */
+#ifndef NDEBUG
+static bool workspaces_is_screen_used
+#else
+static bool UNUSED_FUNCTION(workspaces_is_screen_used)
+#endif
+    (const Main *bmain, bScreen *screen)
+{
+  for (WorkSpace *workspace = static_cast(bmain->workspaces.first); workspace;
+       workspace = static_cast(workspace->id.next)) {
+    if (workspace_layout_find_exec(workspace, screen)) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Create, Delete, Init
+ * \{ */
+
+WorkSpace *BKE_workspace_add(Main *bmain, const char *name)
+{
+  WorkSpace *new_workspace = static_cast(BKE_id_new(bmain, ID_WS, name));
+  id_us_ensure_real(&new_workspace->id);
+  return new_workspace;
+}
+
+void BKE_workspace_remove(Main *bmain, WorkSpace *workspace)
+{
+  for (WorkSpaceLayout *layout = static_cast(workspace->layouts.first),
+                       *layout_next;
+       layout;
+       layout = layout_next) {
+    layout_next = layout->next;
+    BKE_workspace_layout_remove(bmain, workspace, layout);
+  }
+  BKE_id_free(bmain, workspace);
+}
+
+WorkSpaceInstanceHook *BKE_workspace_instance_hook_create(const Main *bmain, const int winid)
+{
+  WorkSpaceInstanceHook *hook = MEM_cnew(__func__);
+
+  /* set an active screen-layout for each possible window/workspace combination */
+  for (WorkSpace *workspace = static_cast(bmain->workspaces.first); workspace;
+       workspace = static_cast(workspace->id.next)) {
+    BKE_workspace_active_layout_set(
+        hook, winid, workspace, static_cast(workspace->layouts.first));
+  }
+
+  return hook;
+}
+void BKE_workspace_instance_hook_free(const Main *bmain, WorkSpaceInstanceHook *hook)
+{
+  /* workspaces should never be freed before wm (during which we call this function).
+   * However, when running in background mode, loading a blend file may allocate windows (that need
+   * to be freed) without creating workspaces. This happens in BlendfileLoadingBaseTest. */
+  BLI_assert(!BLI_listbase_is_empty(&bmain->workspaces) || G.background);
+
+  /* Free relations for this hook */
+  for (WorkSpace *workspace = static_cast(bmain->workspaces.first); workspace;
+       workspace = static_cast(workspace->id.next)) {
+    for (WorkSpaceDataRelation *relation = static_cast(
+                                   workspace->hook_layout_relations.first),
+                               *relation_next;
+         relation;
+         relation = relation_next) {
+      relation_next = relation->next;
+      if (relation->parent == hook) {
+        workspace_relation_remove(&workspace->hook_layout_relations, relation);
+      }
+    }
+  }
+
+  MEM_freeN(hook);
+}
+
+WorkSpaceLayout *BKE_workspace_layout_add(Main *bmain,
+                                          WorkSpace *workspace,
+                                          bScreen *screen,
+                                          const char *name)
+{
+  WorkSpaceLayout *layout = MEM_cnew(__func__);
+
+  BLI_assert(!workspaces_is_screen_used(bmain, screen));
+#ifndef DEBUG
+  UNUSED_VARS(bmain);
+#endif
+  layout->screen = screen;
+  id_us_plus(&layout->screen->id);
+  workspace_layout_name_set(workspace, layout, name);
+  BLI_addtail(&workspace->layouts, layout);
+
+  return layout;
+}
+
+void BKE_workspace_layout_remove(Main *bmain, WorkSpace *workspace, WorkSpaceLayout *layout)
+{
+  /* Screen should usually be set, but we call this from file reading to get rid of invalid
+   * layouts. */
+  if (layout->screen) {
+    id_us_min(&layout->screen->id);
+    BKE_id_free(bmain, layout->screen);
+  }
+  BLI_freelinkN(&workspace->layouts, layout);
+}
+
+void BKE_workspace_relations_free(ListBase *relation_list)
+{
+  for (WorkSpaceDataRelation *
+           relation = static_cast(relation_list->first),
+          *relation_next;
+       relation;
+       relation = relation_next) {
+    relation_next = relation->next;
+    workspace_relation_remove(relation_list, relation);
+  }
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name General Utils
+ * \{ */
+
+WorkSpaceLayout *BKE_workspace_layout_find(const WorkSpace *workspace, const bScreen *screen)
+{
+  WorkSpaceLayout *layout = workspace_layout_find_exec(workspace, screen);
+  if (layout) {
+    return layout;
+  }
+
+  printf(
+      "%s: Couldn't find layout in this workspace: '%s' screen: '%s'. "
+      "This should not happen!\n",
+      __func__,
+      workspace->id.name + 2,
+      screen->id.name + 2);
+
+  return nullptr;
+}
+
+WorkSpaceLayout *BKE_workspace_layout_find_global(const Main *bmain,
+                                                  const bScreen *screen,
+                                                  WorkSpace **r_workspace)
+{
+  WorkSpaceLayout *layout;
+
+  if (r_workspace) {
+    *r_workspace = nullptr;
+  }
+
+  for (WorkSpace *workspace = static_cast(bmain->workspaces.first); workspace;
+       workspace = static_cast(workspace->id.next)) {
+    if ((layout = workspace_layout_find_exec(workspace, screen))) {
+      if (r_workspace) {
+        *r_workspace = workspace;
+      }
+
+      return layout;
+    }
+  }
+
+  return nullptr;
+}
+
+WorkSpaceLayout *BKE_workspace_layout_iter_circular(const WorkSpace *workspace,
+                                                    WorkSpaceLayout *start,
+                                                    bool (*callback)(const WorkSpaceLayout *layout,
+                                                                     void *arg),
+                                                    void *arg,
+                                                    const bool iter_backward)
+{
+  WorkSpaceLayout *iter_layout;
+
+  if (iter_backward) {
+    LISTBASE_CIRCULAR_BACKWARD_BEGIN (WorkSpaceLayout *, &workspace->layouts, iter_layout, start) {
+      if (!callback(iter_layout, arg)) {
+        return iter_layout;
+      }
+    }
+    LISTBASE_CIRCULAR_BACKWARD_END(WorkSpaceLayout *, &workspace->layouts, iter_layout, start);
+  }
+  else {
+    LISTBASE_CIRCULAR_FORWARD_BEGIN (WorkSpaceLayout *, &workspace->layouts, iter_layout, start) {
+      if (!callback(iter_layout, arg)) {
+        return iter_layout;
+      }
+    }
+    LISTBASE_CIRCULAR_FORWARD_END(WorkSpaceLayout *, &workspace->layouts, iter_layout, start);
+  }
+
+  return nullptr;
+}
+
+void BKE_workspace_tool_remove(struct WorkSpace *workspace, struct bToolRef *tref)
+{
+  if (tref->runtime) {
+    MEM_freeN(tref->runtime);
+  }
+  if (tref->properties) {
+    IDP_FreeProperty(tref->properties);
+  }
+  BLI_remlink(&workspace->tools, tref);
+  MEM_freeN(tref);
+}
+
+bool BKE_workspace_owner_id_check(const WorkSpace *workspace, const char *owner_id)
+{
+  if ((*owner_id == '\0') || ((workspace->flags & WORKSPACE_USE_FILTER_BY_ORIGIN) == 0)) {
+    return true;
+  }
+
+  /* We could use hash lookup, for now this list is highly likely under < ~16 items. */
+  return BLI_findstring(&workspace->owner_ids, owner_id, offsetof(wmOwnerID, name)) != nullptr;
+}
+
+void BKE_workspace_id_tag_all_visible(Main *bmain, int tag)
+{
+  BKE_main_id_tag_listbase(&bmain->workspaces, tag, false);
+  wmWindowManager *wm = static_cast(bmain->wm.first);
+  LISTBASE_FOREACH (wmWindow *, win, &wm->windows) {
+    WorkSpace *workspace = BKE_workspace_active_get(win->workspace_hook);
+    workspace->id.tag |= tag;
+  }
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Getters/Setters
+ * \{ */
+
+WorkSpace *BKE_workspace_active_get(WorkSpaceInstanceHook *hook)
+{
+  return hook->active;
+}
+void BKE_workspace_active_set(WorkSpaceInstanceHook *hook, WorkSpace *workspace)
+{
+  /* DO NOT check for `hook->active == workspace` here. Caller code is supposed to do it if
+   * that optimization is possible and needed.
+   * This code can be called from places where we might have this equality, but still want to
+   * ensure/update the active layout below.
+   * Known case where this is buggy and will crash later due to nullptr active layout: reading
+   * a blend file, when the new read workspace ID happens to have the exact same memory address
+   * as when it was saved in the blend file (extremely unlikely, but possible). */
+
+  hook->active = workspace;
+  if (workspace) {
+    WorkSpaceLayout *layout = static_cast(
+        workspace_relation_get_data_matching_parent(&workspace->hook_layout_relations, hook));
+    if (layout) {
+      hook->act_layout = layout;
+    }
+  }
+}
+
+WorkSpaceLayout *BKE_workspace_active_layout_get(const WorkSpaceInstanceHook *hook)
+{
+  return hook->act_layout;
+}
+
+WorkSpaceLayout *BKE_workspace_active_layout_for_workspace_get(const WorkSpaceInstanceHook *hook,
+                                                               const WorkSpace *workspace)
+{
+  /* If the workspace is active, the active layout can be returned, no need for a lookup. */
+  if (hook->active == workspace) {
+    return hook->act_layout;
+  }
+
+  /* Inactive workspace */
+  return static_cast(
+      workspace_relation_get_data_matching_parent(&workspace->hook_layout_relations, hook));
+}
+
+void BKE_workspace_active_layout_set(WorkSpaceInstanceHook *hook,
+                                     const int winid,
+                                     WorkSpace *workspace,
+                                     WorkSpaceLayout *layout)
+{
+  hook->act_layout = layout;
+  workspace_relation_ensure_updated(&workspace->hook_layout_relations, hook, winid, layout);
+}
+
+bScreen *BKE_workspace_active_screen_get(const WorkSpaceInstanceHook *hook)
+{
+  return hook->act_layout->screen;
+}
+void BKE_workspace_active_screen_set(WorkSpaceInstanceHook *hook,
+                                     const int winid,
+                                     WorkSpace *workspace,
+                                     bScreen *screen)
+{
+  /* we need to find the WorkspaceLayout that wraps this screen */
+  WorkSpaceLayout *layout = BKE_workspace_layout_find(hook->active, screen);
+  BKE_workspace_active_layout_set(hook, winid, workspace, layout);
+}
+
+const char *BKE_workspace_layout_name_get(const WorkSpaceLayout *layout)
+{
+  return layout->name;
+}
+void BKE_workspace_layout_name_set(WorkSpace *workspace,
+                                   WorkSpaceLayout *layout,
+                                   const char *new_name)
+{
+  workspace_layout_name_set(workspace, layout, new_name);
+}
+
+bScreen *BKE_workspace_layout_screen_get(const WorkSpaceLayout *layout)
+{
+  return layout->screen;
+}
+
+/** \} */
diff --git a/source/blender/blenkernel/intern/world.c b/source/blender/blenkernel/intern/world.c
index cc3ee06f539..c6c50ee068c 100644
--- a/source/blender/blenkernel/intern/world.c
+++ b/source/blender/blenkernel/intern/world.c
@@ -98,6 +98,7 @@ static void world_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const int
       BKE_id_copy_ex(
           bmain, (ID *)wrld_src->nodetree, (ID **)&wrld_dst->nodetree, flag_private_id_data);
     }
+    wrld_dst->nodetree->owner_id = &wrld_dst->id;
   }
 
   BLI_listbase_clear(&wrld_dst->gpumaterial);
@@ -197,7 +198,7 @@ IDTypeInfo IDType_ID_WO = {
     .foreach_id = world_foreach_id,
     .foreach_cache = NULL,
     .foreach_path = NULL,
-    .owner_get = NULL,
+    .owner_pointer_get = NULL,
 
     .blend_write = world_blend_write,
     .blend_read_data = world_blend_read_data,
diff --git a/source/blender/blenkernel/intern/writeffmpeg.c b/source/blender/blenkernel/intern/writeffmpeg.c
index 5e11cd0703a..883591e3e87 100644
--- a/source/blender/blenkernel/intern/writeffmpeg.c
+++ b/source/blender/blenkernel/intern/writeffmpeg.c
@@ -1485,7 +1485,7 @@ void BKE_ffmpeg_preset_set(RenderData *rd, int preset)
   }
 }
 
-void BKE_ffmpeg_image_type_verify(RenderData *rd, ImageFormatData *imf)
+void BKE_ffmpeg_image_type_verify(RenderData *rd, const ImageFormatData *imf)
 {
   int audio = 0;
 
diff --git a/source/blender/blenkernel/nla_private.h b/source/blender/blenkernel/nla_private.h
index 41d1eef733c..96aecadd3f5 100644
--- a/source/blender/blenkernel/nla_private.h
+++ b/source/blender/blenkernel/nla_private.h
@@ -128,7 +128,7 @@ typedef struct NlaEvalData {
   int num_channels;
   NlaEvalSnapshot base_snapshot;
 
-  /* Evaluation result shapshot. */
+  /* Evaluation result snapshot. */
   NlaEvalSnapshot eval_snapshot;
 } NlaEvalData;
 
@@ -241,6 +241,17 @@ void nlasnapshot_blend_get_inverted_upper_snapshot(NlaEvalData *eval_data,
                                                    float upper_influence,
                                                    NlaEvalSnapshot *r_upper_snapshot);
 
+/**
+ * Using \a blended_snapshot and \a upper_snapshot, we can solve for the \a r_lower_snapshot.
+ *
+ * Only channels that exist within \a blended_snapshot are processed.
+ * Only blended values within the \a remap_domain are processed.
+ *
+ * Writes to \a r_upper_snapshot `NlaEvalChannelSnapshot->remap_domain` to match remapping success.
+ *
+ * Assumes caller marked upper values that are in the \a blend_domain. This determines whether the
+ * blended value came directly from the lower snapshot or a result of blending.
+ */
 void nlasnapshot_blend_get_inverted_lower_snapshot(NlaEvalData *eval_data,
                                                    NlaEvalSnapshot *blended_snapshot,
                                                    NlaEvalSnapshot *upper_snapshot,
diff --git a/source/blender/blenlib/BLI_any.hh b/source/blender/blenlib/BLI_any.hh
index a20239f214f..f9b53436763 100644
--- a/source/blender/blenlib/BLI_any.hh
+++ b/source/blender/blenlib/BLI_any.hh
@@ -39,7 +39,7 @@ template struct AnyTypeInfo {
  * Used when #T is stored directly in the inline buffer of the #Any.
  */
 template
-static constexpr AnyTypeInfo info_for_inline = {
+inline constexpr AnyTypeInfo info_for_inline = {
     is_trivially_copy_constructible_extended_v ?
         nullptr :
         +[](void *dst, const void *src) { new (dst) T(*(const T *)src); },
@@ -57,7 +57,7 @@ static constexpr AnyTypeInfo info_for_inline = {
  */
 template using Ptr = std::unique_ptr;
 template
-static constexpr AnyTypeInfo info_for_unique_ptr = {
+inline constexpr AnyTypeInfo info_for_unique_ptr = {
     [](void *dst, const void *src) { new (dst) Ptr(new T(**(const Ptr *)src)); },
     [](void *dst, void *src) { new (dst) Ptr(new T(std::move(**(Ptr *)src))); },
     [](void *src) { std::destroy_at((Ptr *)src); },
diff --git a/source/blender/blenlib/BLI_array_store.h b/source/blender/blenlib/BLI_array_store.h
index 8a91825da6f..c04c392627d 100644
--- a/source/blender/blenlib/BLI_array_store.h
+++ b/source/blender/blenlib/BLI_array_store.h
@@ -57,7 +57,6 @@ size_t BLI_array_store_calc_size_expanded_get(const BArrayStore *bs);
 size_t BLI_array_store_calc_size_compacted_get(const BArrayStore *bs);
 
 /**
- *
  * \param data: Data used to create
  * \param state_reference: The state to use as a reference when adding the new state,
  * typically this is the previous state,
diff --git a/source/blender/blenlib/BLI_array_utils.hh b/source/blender/blenlib/BLI_array_utils.hh
new file mode 100644
index 00000000000..95b3bde10f4
--- /dev/null
+++ b/source/blender/blenlib/BLI_array_utils.hh
@@ -0,0 +1,110 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#pragma once
+
+#include "BLI_generic_span.hh"
+#include "BLI_generic_virtual_array.hh"
+#include "BLI_index_mask.hh"
+#include "BLI_task.hh"
+#include "BLI_virtual_array.hh"
+
+namespace blender::array_utils {
+
+/**
+ * Fill the destination span by copying masked values from the `src` array. Threaded based on
+ * grain-size.
+ */
+void copy(const GVArray &src, IndexMask selection, GMutableSpan dst, int64_t grain_size = 4096);
+
+/**
+ * Fill the destination span by copying values from the `src` array. Threaded based on
+ * grain-size.
+ */
+template
+inline void copy(const Span src,
+                 const IndexMask selection,
+                 MutableSpan dst,
+                 const int64_t grain_size = 4096)
+{
+  BLI_assert(src.size() == dst.size());
+  threading::parallel_for(selection.index_range(), grain_size, [&](const IndexRange range) {
+    for (const int64_t index : selection.slice(range)) {
+      dst[index] = src[index];
+    }
+  });
+}
+
+/**
+ * Fill the destination span by gathering indexed values from the `src` array.
+ */
+void gather(const GVArray &src, IndexMask indices, GMutableSpan dst, int64_t grain_size = 4096);
+
+/**
+ * Fill the destination span by gathering indexed values from the `src` array.
+ */
+template
+inline void gather(const VArray &src,
+                   const IndexMask indices,
+                   MutableSpan dst,
+                   const int64_t grain_size = 4096)
+{
+  BLI_assert(indices.size() == dst.size());
+  threading::parallel_for(indices.index_range(), grain_size, [&](const IndexRange range) {
+    src.materialize_compressed_to_uninitialized(indices.slice(range), dst.slice(range).data());
+  });
+}
+
+/**
+ * Fill the destination span by gathering indexed values from the `src` array.
+ */
+template
+inline void gather(const Span src,
+                   const IndexMask indices,
+                   MutableSpan dst,
+                   const int64_t grain_size = 4096)
+{
+  BLI_assert(indices.size() == dst.size());
+  threading::parallel_for(indices.index_range(), grain_size, [&](const IndexRange range) {
+    for (const int64_t i : range) {
+      dst[i] = src[indices[i]];
+    }
+  });
+}
+
+/**
+ * Fill the destination span by gathering indexed values from the `src` array.
+ */
+template
+inline void gather(const Span src,
+                   const Span indices,
+                   MutableSpan dst,
+                   const int64_t grain_size = 4096)
+{
+  BLI_assert(indices.size() == dst.size());
+  threading::parallel_for(indices.index_range(), grain_size, [&](const IndexRange range) {
+    for (const int64_t i : range) {
+      dst[i] = src[indices[i]];
+    }
+  });
+}
+
+/**
+ * Fill the destination span by gathering indexed values from the `src` array.
+ */
+template
+inline void gather(const VArray &src,
+                   const Span indices,
+                   MutableSpan dst,
+                   const int64_t grain_size = 4096)
+{
+  BLI_assert(indices.size() == dst.size());
+  devirtualize_varray(src, [&](const auto &src) {
+    threading::parallel_for(indices.index_range(), grain_size, [&](const IndexRange range) {
+      for (const int64_t i : range) {
+        dst[i] = src[indices[i]];
+      }
+    });
+  });
+}
+
+}  // namespace blender::array_utils
diff --git a/source/blender/blenlib/BLI_bit_vector.hh b/source/blender/blenlib/BLI_bit_vector.hh
new file mode 100644
index 00000000000..2cec190f84a
--- /dev/null
+++ b/source/blender/blenlib/BLI_bit_vector.hh
@@ -0,0 +1,529 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#pragma once
+
+/** \file
+ * \ingroup bli
+ *
+ * A `blender::BitVector` is a dynamically growing contiguous arrays of bits. Its main purpose is
+ * to provide a compact way to map indices to bools. It requires 8 times less memory compared to a
+ * `blender::Vector`.
+ *
+ * Advantages of using a bit- instead of byte-vector are:
+ * - Uses less memory.
+ * - Allows checking the state of many elements at the same time (8 times more bits than bytes fit
+ *   into a CPU register). This can improve performance.
+ *
+ * The compact nature of storing bools in individual bits has some downsides that have to be kept
+ * in mind:
+ * - Writing to separate bits in the same byte is not thread-safe. Therefore, an existing vector of
+ *   bool can't easily be replaced with a bit vector, if it is written to from multiple threads.
+ *   Read-only access from multiple threads is fine though.
+ * - Writing individual elements is more expensive when the array is in cache already. That is
+ *   because changing a bit is always a read-modify-write operation on the byte the bit resides in.
+ * - Reading individual elements is more expensive when the array is in cache already. That is
+ *   because additional bit-wise operations have to be applied after the corresponding byte is
+ *   read.
+ *
+ * Comparison to `std::vector`:
+ * - `blender::BitVector` has an interface that is more optimized for dealing with bits.
+ * - `blender::BitVector` has an inline buffer that is used to avoid allocations when the vector is
+ *   small.
+ *
+ * Comparison to `BLI_bitmap`:
+ * - `blender::BitVector` offers a more C++ friendly interface.
+ * - `BLI_bitmap` should only be used in C code that can not use `blender::BitVector`.
+ */
+
+#include 
+
+#include "BLI_allocator.hh"
+#include "BLI_index_range.hh"
+#include "BLI_memory_utils.hh"
+#include "BLI_span.hh"
+
+namespace blender {
+
+/**
+ * This is a read-only pointer to a specific bit. The value of the bit can be retrieved, but not
+ * changed.
+ */
+class BitRef {
+ private:
+  /** Points to the exact byte that the bit is in. */
+  const uint8_t *byte_ptr_;
+  /** All zeros except for a single one at the bit that is referenced. */
+  uint8_t mask_;
+
+  friend class MutableBitRef;
+
+ public:
+  BitRef() = default;
+
+  /**
+   * Reference a specific bit in a byte array. Note that #byte_ptr does *not* have to point to the
+   * exact byte the bit is in.
+   */
+  BitRef(const uint8_t *byte_ptr, const int64_t bit_index)
+  {
+    byte_ptr_ = byte_ptr + (bit_index >> 3);
+    mask_ = 1 << (bit_index & 7);
+  }
+
+  /**
+   * Return true when the bit is currently 1 and false otherwise.
+   */
+  bool test() const
+  {
+    const uint8_t byte = *byte_ptr_;
+    const uint8_t masked_byte = byte & mask_;
+    return masked_byte != 0;
+  }
+
+  operator bool() const
+  {
+    return this->test();
+  }
+};
+
+/**
+ * Similar to #BitRef, but also allows changing the referenced bit.
+ */
+class MutableBitRef {
+ private:
+  /** Points to the exact byte that the bit is in. */
+  uint8_t *byte_ptr_;
+  /** All zeros except for a single one at the bit that is referenced. */
+  uint8_t mask_;
+
+ public:
+  MutableBitRef() = default;
+
+  /**
+   * Reference a specific bit in a byte array. Note that #byte_ptr does *not* have to point to the
+   * exact byte the bit is in.
+   */
+  MutableBitRef(uint8_t *byte_ptr, const int64_t bit_index)
+  {
+    byte_ptr_ = byte_ptr + (bit_index >> 3);
+    mask_ = 1 << static_cast(bit_index & 7);
+  }
+
+  /**
+   * Support implicitly casting to a read-only #BitRef.
+   */
+  operator BitRef() const
+  {
+    BitRef bit_ref;
+    bit_ref.byte_ptr_ = byte_ptr_;
+    bit_ref.mask_ = mask_;
+    return bit_ref;
+  }
+
+  /**
+   * Return true when the bit is currently 1 and false otherwise.
+   */
+  bool test() const
+  {
+    const uint8_t byte = *byte_ptr_;
+    const uint8_t masked_byte = byte & mask_;
+    return masked_byte != 0;
+  }
+
+  operator bool() const
+  {
+    return this->test();
+  }
+
+  /**
+   * Change the bit to a 1.
+   */
+  void set()
+  {
+    *byte_ptr_ |= mask_;
+  }
+
+  /**
+   * Change the bit to a 0.
+   */
+  void reset()
+  {
+    *byte_ptr_ &= ~mask_;
+  }
+
+  /**
+   * Change the bit to a 1 if #value is true and 0 otherwise.
+   */
+  void set(const bool value)
+  {
+    if (value) {
+      this->set();
+    }
+    else {
+      this->reset();
+    }
+  }
+};
+
+template<
+    /**
+     * Number of bits that can be stored in the vector without doing an allocation.
+     */
+    int64_t InlineBufferCapacity = 32,
+    /**
+     * The allocator used by this vector. Should rarely be changed, except when you don't want that
+     * MEM_* is used internally.
+     */
+    typename Allocator = GuardedAllocator>
+class BitVector {
+ private:
+  static constexpr int64_t required_bytes_for_bits(const int64_t number_of_bits)
+  {
+    return (number_of_bits + BitsPerByte - 1) / BitsPerByte;
+  }
+
+  static constexpr int64_t BitsPerByte = 8;
+  static constexpr int64_t BytesInInlineBuffer = required_bytes_for_bits(InlineBufferCapacity);
+  static constexpr int64_t BitsInInlineBuffer = BytesInInlineBuffer * BitsPerByte;
+  static constexpr int64_t AllocationAlignment = 8;
+
+  /**
+   * Points to the first byte used by the vector. It might point to the memory in the inline
+   * buffer.
+   */
+  uint8_t *data_;
+
+  /** Current size of the vector in bits. */
+  int64_t size_in_bits_;
+
+  /** Number of bits that fit into the vector until a reallocation has to occur. */
+  int64_t capacity_in_bits_;
+
+  /** Used for allocations when the inline buffer is too small. */
+  Allocator allocator_;
+
+  /** Contains the bits as long as the vector is small enough. */
+  TypedBuffer inline_buffer_;
+
+ public:
+  BitVector(Allocator allocator = {}) noexcept : allocator_(allocator)
+  {
+    data_ = inline_buffer_;
+    size_in_bits_ = 0;
+    capacity_in_bits_ = BitsInInlineBuffer;
+    uninitialized_fill_n(data_, BytesInInlineBuffer, static_cast(0));
+  }
+
+  BitVector(NoExceptConstructor, Allocator allocator = {}) noexcept : BitVector(allocator)
+  {
+  }
+
+  BitVector(const BitVector &other) : BitVector(NoExceptConstructor(), other.allocator_)
+  {
+    const int64_t bytes_to_copy = other.used_bytes_amount();
+    if (other.size_in_bits_ <= BitsInInlineBuffer) {
+      /* The data is copied into the owned inline buffer. */
+      data_ = inline_buffer_;
+      capacity_in_bits_ = BitsInInlineBuffer;
+    }
+    else {
+      /* Allocate a new byte array because the inline buffer is too small. */
+      data_ = static_cast(
+          allocator_.allocate(bytes_to_copy, AllocationAlignment, __func__));
+      capacity_in_bits_ = bytes_to_copy * BitsPerByte;
+    }
+    size_in_bits_ = other.size_in_bits_;
+    uninitialized_copy_n(other.data_, bytes_to_copy, data_);
+  }
+
+  BitVector(BitVector &&other) noexcept : BitVector(NoExceptConstructor(), other.allocator_)
+  {
+    if (other.is_inline()) {
+      /* Copy the data into the inline buffer. */
+      const int64_t bytes_to_copy = other.used_bytes_amount();
+      data_ = inline_buffer_;
+      uninitialized_copy_n(other.data_, bytes_to_copy, data_);
+    }
+    else {
+      /* Steal the pointer. */
+      data_ = other.data_;
+    }
+    size_in_bits_ = other.size_in_bits_;
+    capacity_in_bits_ = other.capacity_in_bits_;
+
+    /* Clear the other vector because it has been moved from. */
+    other.data_ = other.inline_buffer_;
+    other.size_in_bits_ = 0;
+    other.capacity_in_bits_ = BitsInInlineBuffer;
+  }
+
+  /**
+   * Create a new vector with the given size and fill it with #value.
+   */
+  BitVector(const int64_t size_in_bits, const bool value = false, Allocator allocator = {})
+      : BitVector(NoExceptConstructor(), allocator)
+  {
+    this->resize(size_in_bits, value);
+  }
+
+  /**
+   * Create a bit vector based on an array of bools. Each byte of the input array maps to one bit.
+   */
+  explicit BitVector(const Span values, Allocator allocator = {})
+      : BitVector(NoExceptConstructor(), allocator)
+  {
+    this->resize(values.size());
+    for (const int64_t i : this->index_range()) {
+      (*this)[i].set(values[i]);
+    }
+  }
+
+  ~BitVector()
+  {
+    if (!this->is_inline()) {
+      allocator_.deallocate(data_);
+    }
+  }
+
+  BitVector &operator=(const BitVector &other)
+  {
+    return copy_assign_container(*this, other);
+  }
+
+  BitVector &operator=(BitVector &&other)
+  {
+    return move_assign_container(*this, std::move(other));
+  }
+
+  /**
+   * Number of bits in the bit vector.
+   */
+  int64_t size() const
+  {
+    return size_in_bits_;
+  }
+
+  /**
+   * Get a read-only reference to a specific bit.
+   */
+  BitRef operator[](const int64_t index) const
+  {
+    BLI_assert(index >= 0);
+    BLI_assert(index < size_in_bits_);
+    return {data_, index};
+  }
+
+  /**
+   * Get a mutable reference to a specific bit.
+   */
+  MutableBitRef operator[](const int64_t index)
+  {
+    BLI_assert(index >= 0);
+    BLI_assert(index < size_in_bits_);
+    return {data_, index};
+  }
+
+  IndexRange index_range() const
+  {
+    return {0, size_in_bits_};
+  }
+
+  /**
+   * Add a new bit to the end of the vector.
+   */
+  void append(const bool value)
+  {
+    this->ensure_space_for_one();
+    MutableBitRef bit{data_, size_in_bits_};
+    bit.set(value);
+    size_in_bits_++;
+  }
+
+  class Iterator {
+   private:
+    const BitVector *vector_;
+    int64_t index_;
+
+   public:
+    Iterator(const BitVector &vector, const int64_t index) : vector_(&vector), index_(index)
+    {
+    }
+
+    Iterator &operator++()
+    {
+      index_++;
+      return *this;
+    }
+
+    friend bool operator!=(const Iterator &a, const Iterator &b)
+    {
+      BLI_assert(a.vector_ == b.vector_);
+      return a.index_ != b.index_;
+    }
+
+    BitRef operator*() const
+    {
+      return (*vector_)[index_];
+    }
+  };
+
+  class MutableIterator {
+   private:
+    BitVector *vector_;
+    int64_t index_;
+
+   public:
+    MutableIterator(BitVector &vector, const int64_t index) : vector_(&vector), index_(index)
+    {
+    }
+
+    MutableIterator &operator++()
+    {
+      index_++;
+      return *this;
+    }
+
+    friend bool operator!=(const MutableIterator &a, const MutableIterator &b)
+    {
+      BLI_assert(a.vector_ == b.vector_);
+      return a.index_ != b.index_;
+    }
+
+    MutableBitRef operator*() const
+    {
+      return (*vector_)[index_];
+    }
+  };
+
+  Iterator begin() const
+  {
+    return {*this, 0};
+  }
+
+  Iterator end() const
+  {
+    return {*this, size_in_bits_};
+  }
+
+  MutableIterator begin()
+  {
+    return {*this, 0};
+  }
+
+  MutableIterator end()
+  {
+    return {*this, size_in_bits_};
+  }
+
+  /**
+   * Change the size of the vector. If the new vector is larger than the old one, the new elements
+   * are filled with #value.
+   */
+  void resize(const int64_t new_size_in_bits, const bool value = false)
+  {
+    BLI_assert(new_size_in_bits >= 0);
+    const int64_t old_size_in_bits = size_in_bits_;
+    if (new_size_in_bits > old_size_in_bits) {
+      this->reserve(new_size_in_bits);
+    }
+    size_in_bits_ = new_size_in_bits;
+    if (old_size_in_bits < new_size_in_bits) {
+      this->fill_range(IndexRange(old_size_in_bits, new_size_in_bits - old_size_in_bits), value);
+    }
+  }
+
+  /**
+   * Set #value for every element in #range.
+   */
+  void fill_range(const IndexRange range, const bool value)
+  {
+    const AlignedIndexRanges aligned_ranges = split_index_range_by_alignment(range, BitsPerByte);
+
+    /* Fill first few bits. */
+    for (const int64_t i : aligned_ranges.prefix) {
+      (*this)[i].set(value);
+    }
+
+    /* Fill entire bytes at once. */
+    const int64_t start_fill_byte_index = aligned_ranges.aligned.start() / BitsPerByte;
+    const int64_t bytes_to_fill = aligned_ranges.aligned.size() / BitsPerByte;
+    const uint8_t fill_value = value ? (uint8_t)0xff : (uint8_t)0x00;
+    initialized_fill_n(data_ + start_fill_byte_index, bytes_to_fill, fill_value);
+
+    /* Fill bits in the end that don't cover a full byte. */
+    for (const int64_t i : aligned_ranges.suffix) {
+      (*this)[i].set(value);
+    }
+  }
+
+  /**
+   * Set #value on every element.
+   */
+  void fill(const bool value)
+  {
+    this->fill_range(IndexRange(0, size_in_bits_), value);
+  }
+
+  /**
+   * Make sure that the capacity of the vector is large enough to hold the given amount of bits.
+   * The actual size is not changed.
+   */
+  void reserve(const int new_capacity_in_bits)
+  {
+    this->realloc_to_at_least(new_capacity_in_bits);
+  }
+
+ private:
+  void ensure_space_for_one()
+  {
+    if (UNLIKELY(size_in_bits_ >= capacity_in_bits_)) {
+      this->realloc_to_at_least(size_in_bits_ + 1);
+    }
+  }
+
+  BLI_NOINLINE void realloc_to_at_least(const int64_t min_capacity_in_bits,
+                                        const uint8_t initial_value_for_new_bytes = 0x00)
+  {
+    if (capacity_in_bits_ >= min_capacity_in_bits) {
+      return;
+    }
+
+    const int64_t min_capacity_in_bytes = this->required_bytes_for_bits(min_capacity_in_bits);
+
+    /* At least double the size of the previous allocation. */
+    const int64_t min_new_capacity_in_bytes = capacity_in_bits_ * 2;
+
+    const int64_t new_capacity_in_bytes = std::max(min_capacity_in_bytes,
+                                                   min_new_capacity_in_bytes);
+    const int64_t bytes_to_copy = this->used_bytes_amount();
+
+    uint8_t *new_data = static_cast(
+        allocator_.allocate(new_capacity_in_bytes, AllocationAlignment, __func__));
+    uninitialized_copy_n(data_, bytes_to_copy, new_data);
+    /* Always initialize new capacity even if it isn't used yet. That's necessary to avoid warnings
+     * caused by using uninitialized memory. This happens when e.g. setting a clearing a bit in an
+     * uninitialized byte. */
+    uninitialized_fill_n(new_data + bytes_to_copy,
+                         new_capacity_in_bytes - bytes_to_copy,
+                         (uint8_t)initial_value_for_new_bytes);
+
+    if (!this->is_inline()) {
+      allocator_.deallocate(data_);
+    }
+
+    data_ = new_data;
+    capacity_in_bits_ = new_capacity_in_bytes * BitsPerByte;
+  }
+
+  bool is_inline() const
+  {
+    return data_ == inline_buffer_;
+  }
+
+  int64_t used_bytes_amount() const
+  {
+    return this->required_bytes_for_bits(size_in_bits_);
+  }
+};
+
+}  // namespace blender
diff --git a/source/blender/blenlib/BLI_bitmap.h b/source/blender/blenlib/BLI_bitmap.h
index 19d8525311c..973cc5c3d1e 100644
--- a/source/blender/blenlib/BLI_bitmap.h
+++ b/source/blender/blenlib/BLI_bitmap.h
@@ -27,7 +27,7 @@ typedef unsigned int BLI_bitmap;
 /**
  * Number of blocks needed to hold '_num' bits.
  */
-#define _BITMAP_NUM_BLOCKS(_num) (((_num) >> _BITMAP_POWER) + 1)
+#define _BITMAP_NUM_BLOCKS(_num) (((_num) + _BITMAP_MASK) >> _BITMAP_POWER)
 
 /**
  * Size (in bytes) used to hold '_num' bits.
@@ -53,6 +53,11 @@ typedef unsigned int BLI_bitmap;
   (CHECK_TYPE_INLINE(_mem, MemArena *), \
    ((BLI_bitmap *)BLI_memarena_calloc(_mem, BLI_BITMAP_SIZE(_num))))
 
+/**
+ * Declares a bitmap as a variable.
+ */
+#define BLI_BITMAP_DECLARE(_name, _num) BLI_bitmap _name[_BITMAP_NUM_BLOCKS(_num)] = {}
+
 /**
  * Get the value of a single bit at '_index'.
  */
@@ -137,6 +142,12 @@ void BLI_bitmap_and_all(BLI_bitmap *dst, const BLI_bitmap *src, size_t bits);
  */
 void BLI_bitmap_or_all(BLI_bitmap *dst, const BLI_bitmap *src, size_t bits);
 
+/**
+ * Find index of the lowest unset bit.
+ * Returns -1 if all the bits are set.
+ */
+int BLI_bitmap_find_first_unset(const BLI_bitmap *bitmap, size_t bits);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/blender/blenlib/BLI_compute_context.hh b/source/blender/blenlib/BLI_compute_context.hh
new file mode 100644
index 00000000000..e3e5b6f9e85
--- /dev/null
+++ b/source/blender/blenlib/BLI_compute_context.hh
@@ -0,0 +1,173 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#pragma once
+
+/** \file
+ * \ingroup bli
+ *
+ * When logging computed values, we generally want to know where the value was computed. For
+ * example, geometry nodes logs socket values so that they can be displayed in the ui. For that we
+ * can combine the logged value with a `ComputeContext`, which identifies the place where the value
+ * was computed.
+ *
+ * This is not a trivial problem because e.g. just storing a pointer to the socket a value
+ * belongs to is not enough. That's because the same socket may correspond to many different values
+ * when the socket is used in a node group that is used multiple times. In this case, not only does
+ * the socket have to be stored but also the entire nested node group path that led to the
+ * evaluation of the socket.
+ *
+ * Storing the entire "context path" for every logged value is not feasible, because that path can
+ * become quite long. So that would need much more memory, more compute overhead and makes it
+ * complicated to compare if two contexts are the same. If the identifier for a compute context
+ * would have a variable size, it would also be much harder to create a map from context to values.
+ *
+ * The solution implemented below uses the following key ideas:
+ * - Every compute context can be hashed to a unique fixed size value (`ComputeContextHash`). While
+ *   technically there could be hash collisions, the hashing algorithm has to be chosen to make
+ *   that practically impossible. This way an entire context path, possibly consisting of many
+ *   nested contexts, is represented by a single value that can be stored easily.
+ * - A nested compute context is build as singly linked list, where every compute context has a
+ *   pointer to the parent compute context. Note that a link in the other direction is not possible
+ *   because the same parent compute context may be used by many different children which possibly
+ *   run on different threads.
+ */
+
+#include "BLI_array.hh"
+#include "BLI_linear_allocator.hh"
+#include "BLI_stack.hh"
+#include "BLI_string_ref.hh"
+
+namespace blender {
+
+/**
+ * A hash that uniquely identifies a specific (non-fixed-size) compute context. The hash has to
+ * have enough bits to make collisions practically impossible.
+ */
+struct ComputeContextHash {
+  static constexpr int64_t HashSizeInBytes = 16;
+  uint64_t v1 = 0;
+  uint64_t v2 = 0;
+
+  uint64_t hash() const
+  {
+    return v1;
+  }
+
+  friend bool operator==(const ComputeContextHash &a, const ComputeContextHash &b)
+  {
+    return a.v1 == b.v1 && a.v2 == b.v2;
+  }
+
+  void mix_in(const void *data, int64_t len);
+
+  friend std::ostream &operator<<(std::ostream &stream, const ComputeContextHash &hash);
+};
+
+static_assert(sizeof(ComputeContextHash) == ComputeContextHash::HashSizeInBytes);
+
+/**
+ * Identifies the context in which a computation happens. This context can be used to identify
+ * values logged during the computation. For more details, see the comment at the top of the file.
+ *
+ * This class should be subclassed to implement specific contexts.
+ */
+class ComputeContext {
+ private:
+  /**
+   * Only used for debugging currently.
+   */
+  const char *static_type_;
+  /**
+   * Pointer to the context that this context is child of. That allows nesting compute contexts.
+   */
+  const ComputeContext *parent_ = nullptr;
+
+ protected:
+  /**
+   * The hash that uniquely identifies this context. It's a combined hash of this context as well
+   * as all the parent contexts.
+   */
+  ComputeContextHash hash_;
+
+ public:
+  ComputeContext(const char *static_type, const ComputeContext *parent)
+      : static_type_(static_type), parent_(parent)
+  {
+    if (parent != nullptr) {
+      hash_ = parent_->hash_;
+    }
+  }
+  virtual ~ComputeContext() = default;
+
+  const ComputeContextHash &hash() const
+  {
+    return hash_;
+  }
+
+  const char *static_type() const
+  {
+    return static_type_;
+  }
+
+  const ComputeContext *parent() const
+  {
+    return parent_;
+  }
+
+  /**
+   * Print the entire nested context stack.
+   */
+  void print_stack(std::ostream &stream, StringRef name) const;
+
+  /**
+   * Print information about this specific context. This has to be implemented by each subclass.
+   */
+  virtual void print_current_in_line(std::ostream &stream) const = 0;
+
+  friend std::ostream &operator<<(std::ostream &stream, const ComputeContext &compute_context);
+};
+
+/**
+ * Utility class to build a context stack in one place. This is typically used to get the hash that
+ * corresponds to a specific nested compute context, in order to look up corresponding logged
+ * values.
+ */
+class ComputeContextBuilder {
+ private:
+  LinearAllocator<> allocator_;
+  Stack> contexts_;
+
+ public:
+  bool is_empty() const
+  {
+    return contexts_.is_empty();
+  }
+
+  const ComputeContext *current() const
+  {
+    if (contexts_.is_empty()) {
+      return nullptr;
+    }
+    return contexts_.peek().get();
+  }
+
+  const ComputeContextHash hash() const
+  {
+    BLI_assert(!contexts_.is_empty());
+    return this->current()->hash();
+  }
+
+  template void push(Args &&...args)
+  {
+    const ComputeContext *current = this->current();
+    destruct_ptr context = allocator_.construct(current, std::forward(args)...);
+    contexts_.push(std::move(context));
+  }
+
+  void pop()
+  {
+    contexts_.pop();
+  }
+};
+
+}  // namespace blender
diff --git a/source/blender/blenlib/BLI_cpp_type.hh b/source/blender/blenlib/BLI_cpp_type.hh
index cc48b456da7..8cf5ead1c7b 100644
--- a/source/blender/blenlib/BLI_cpp_type.hh
+++ b/source/blender/blenlib/BLI_cpp_type.hh
@@ -20,7 +20,7 @@
  *     cost of longer compile time, a larger binary and the complexity that comes from using
  *     templates).
  *   - If the code is not performance sensitive, it usually makes sense to use #CPPType instead.
- * - Sometimes a combination can make sense. Optimized code can be be generated at compile-time for
+ * - Sometimes a combination can make sense. Optimized code can be generated at compile-time for
  *   some types, while there is a fallback code path using #CPPType for all other types.
  *   #CPPType::to_static_type allows dispatching between both versions based on the type.
  *
diff --git a/source/blender/blenlib/BLI_fileops.h b/source/blender/blenlib/BLI_fileops.h
index 063e60ecf03..0ff75ca16e5 100644
--- a/source/blender/blenlib/BLI_fileops.h
+++ b/source/blender/blenlib/BLI_fileops.h
@@ -101,6 +101,7 @@ typedef enum eFileAttributes {
   FILE_ATTR_MOUNT_POINT = 1 << 14,    /* Volume mounted as a folder. */
   FILE_ATTR_HARDLINK = 1 << 15,       /* Duplicated directory entry. */
 } eFileAttributes;
+ENUM_OPERATORS(eFileAttributes, FILE_ATTR_HARDLINK);
 
 #define FILE_ATTR_ANY_LINK \
   (FILE_ATTR_ALIAS | FILE_ATTR_REPARSE_POINT | FILE_ATTR_SYMLINK | FILE_ATTR_JUNCTION_POINT | \
diff --git a/source/blender/blenlib/BLI_float3x3.hh b/source/blender/blenlib/BLI_float3x3.hh
index 6a9e7dd04f0..178973c155d 100644
--- a/source/blender/blenlib/BLI_float3x3.hh
+++ b/source/blender/blenlib/BLI_float3x3.hh
@@ -63,6 +63,15 @@ struct float3x3 {
     return result;
   }
 
+  static float3x3 from_scale(const float2 scale)
+  {
+    float3x3 result = zero();
+    result.values[0][0] = scale.x;
+    result.values[1][1] = scale.y;
+    result.values[2][2] = 1.0f;
+    return result;
+  }
+
   static float3x3 from_translation_rotation_scale(const float2 translation,
                                                   float rotation,
                                                   const float2 scale)
@@ -190,6 +199,13 @@ struct float3x3 {
     return result;
   }
 
+  float2 scale_2d() const
+  {
+    float2 scale;
+    mat3_to_size_2d(scale, values);
+    return scale;
+  }
+
   friend bool operator==(const float3x3 &a, const float3x3 &b)
   {
     return equals_m3m3(a.values, b.values);
diff --git a/source/blender/blenlib/BLI_float4x4.hh b/source/blender/blenlib/BLI_float4x4.hh
index 64e6e68432f..ca0d9ea0028 100644
--- a/source/blender/blenlib/BLI_float4x4.hh
+++ b/source/blender/blenlib/BLI_float4x4.hh
@@ -266,7 +266,7 @@ struct float4x4 {
       for (int j = 0; j < 4; j++) {
         snprintf(fchar, sizeof(fchar), "%11.6f", mat[j][i]);
         stream << fchar;
-        if (i != 3) {
+        if (j != 3) {
           stream << ", ";
         }
       }
diff --git a/source/blender/blenlib/BLI_function_ref.hh b/source/blender/blenlib/BLI_function_ref.hh
index 5f18e994991..9a38176c988 100644
--- a/source/blender/blenlib/BLI_function_ref.hh
+++ b/source/blender/blenlib/BLI_function_ref.hh
@@ -63,7 +63,6 @@
  *
  *   void some_function(FunctionRef f);
  *   some_function([]() { return 0; });
- *
  */
 
 #include "BLI_memory_utils.hh"
diff --git a/source/blender/blenlib/BLI_generic_span.hh b/source/blender/blenlib/BLI_generic_span.hh
index 143ab235d2e..e7a08988c46 100644
--- a/source/blender/blenlib/BLI_generic_span.hh
+++ b/source/blender/blenlib/BLI_generic_span.hh
@@ -100,6 +100,34 @@ class GSpan {
   {
     return this->slice(range.start(), range.size());
   }
+
+  GSpan drop_front(const int64_t n) const
+  {
+    BLI_assert(n >= 0);
+    const int64_t new_size = std::max(0, size_ - n);
+    return GSpan(*type_, POINTER_OFFSET(data_, type_->size() * n), new_size);
+  }
+
+  GSpan drop_back(const int64_t n) const
+  {
+    BLI_assert(n >= 0);
+    const int64_t new_size = std::max(0, size_ - n);
+    return GSpan(*type_, data_, new_size);
+  }
+
+  GSpan take_front(const int64_t n) const
+  {
+    BLI_assert(n >= 0);
+    const int64_t new_size = std::min(size_, n);
+    return GSpan(*type_, data_, new_size);
+  }
+
+  GSpan take_back(const int64_t n) const
+  {
+    BLI_assert(n >= 0);
+    const int64_t new_size = std::min(size_, n);
+    return GSpan(*type_, POINTER_OFFSET(data_, type_->size() * (size_ - new_size)), new_size);
+  }
 };
 
 /**
@@ -199,6 +227,35 @@ class GMutableSpan {
     return this->slice(range.start(), range.size());
   }
 
+  GMutableSpan drop_front(const int64_t n) const
+  {
+    BLI_assert(n >= 0);
+    const int64_t new_size = std::max(0, size_ - n);
+    return GMutableSpan(*type_, POINTER_OFFSET(data_, type_->size() * n), new_size);
+  }
+
+  GMutableSpan drop_back(const int64_t n) const
+  {
+    BLI_assert(n >= 0);
+    const int64_t new_size = std::max(0, size_ - n);
+    return GMutableSpan(*type_, data_, new_size);
+  }
+
+  GMutableSpan take_front(const int64_t n) const
+  {
+    BLI_assert(n >= 0);
+    const int64_t new_size = std::min(size_, n);
+    return GMutableSpan(*type_, data_, new_size);
+  }
+
+  GMutableSpan take_back(const int64_t n) const
+  {
+    BLI_assert(n >= 0);
+    const int64_t new_size = std::min(size_, n);
+    return GMutableSpan(
+        *type_, POINTER_OFFSET(data_, type_->size() * (size_ - new_size)), new_size);
+  }
+
   /**
    * Copy all values from another span into this span. This invokes undefined behavior when the
    * destination contains uninitialized data and T is not trivially copy constructible.
diff --git a/source/blender/blenlib/BLI_generic_virtual_array.hh b/source/blender/blenlib/BLI_generic_virtual_array.hh
index 43ca16a894f..21549896f45 100644
--- a/source/blender/blenlib/BLI_generic_virtual_array.hh
+++ b/source/blender/blenlib/BLI_generic_virtual_array.hh
@@ -860,6 +860,7 @@ template inline GVArray::GVArray(const VArray &varray)
    * #this is destructed. */
   if (info.type == CommonVArrayInfo::Type::Span && !info.may_have_ownership) {
     *this = GVArray::ForSpan(GSpan(CPPType::get(), info.data, varray.size()));
+    return;
   }
   if (varray.try_assign_GVArray(*this)) {
     return;
diff --git a/source/blender/blenlib/BLI_index_range.hh b/source/blender/blenlib/BLI_index_range.hh
index bd0a7e5bb7a..c259282ca64 100644
--- a/source/blender/blenlib/BLI_index_range.hh
+++ b/source/blender/blenlib/BLI_index_range.hh
@@ -90,10 +90,10 @@ class IndexRange {
       return *this;
     }
 
-    constexpr Iterator operator++(int) const
+    constexpr Iterator operator++(int)
     {
       Iterator copied_iterator = *this;
-      ++copied_iterator;
+      ++(*this);
       return copied_iterator;
     }
 
@@ -140,6 +140,10 @@ class IndexRange {
   {
     return (a.size_ == b.size_) && (a.start_ == b.start_ || a.size_ == 0);
   }
+  constexpr friend bool operator!=(IndexRange a, IndexRange b)
+  {
+    return !(a == b);
+  }
 
   /**
    * Get the amount of numbers in the range.
@@ -197,6 +201,16 @@ class IndexRange {
     return start_ + size_ - 1 - n;
   }
 
+  /**
+   * Get the element one before the beginning. The returned value is undefined when the range is
+   * empty, and the range must start after zero already.
+   */
+  constexpr int64_t one_before_start() const
+  {
+    BLI_assert(start_ > 0);
+    return start_ - 1;
+  }
+
   /**
    * Get the element one after the end. The returned value is undefined when the range is empty.
    */
@@ -237,6 +251,19 @@ class IndexRange {
     return this->slice(range.start(), range.size());
   }
 
+  /**
+   * Returns a new IndexRange that contains the intersection of the current one with the given
+   * range. Returns empty range if there are no overlapping indices. The returned range is always
+   * a valid slice of this range.
+   */
+  constexpr IndexRange intersect(IndexRange other) const
+  {
+    const int64_t old_end = start_ + size_;
+    const int64_t new_start = std::min(old_end, std::max(start_, other.start_));
+    const int64_t new_end = std::max(new_start, std::min(old_end, other.start_ + other.size_));
+    return IndexRange(new_start, new_end - new_start);
+  }
+
   /**
    * Returns a new IndexRange with n elements removed from the beginning of the range.
    * This invokes undefined behavior when n is negative.
@@ -308,4 +335,19 @@ class IndexRange {
   Span as_span_internal() const;
 };
 
+struct AlignedIndexRanges {
+  IndexRange prefix;
+  IndexRange aligned;
+  IndexRange suffix;
+};
+
+/**
+ * Split a range into three parts so that the boundaries of the middle part are aligned to some
+ * power of two.
+ *
+ * This can be used when an algorithm can be optimized on aligned indices/memory. The algorithm
+ * then needs a slow path for the beginning and end, and a fast path for the aligned elements.
+ */
+AlignedIndexRanges split_index_range_by_alignment(const IndexRange range, const int64_t alignment);
+
 }  // namespace blender
diff --git a/source/blender/blenlib/BLI_kdopbvh.h b/source/blender/blenlib/BLI_kdopbvh.h
index 8642d728909..17759b6a8ac 100644
--- a/source/blender/blenlib/BLI_kdopbvh.h
+++ b/source/blender/blenlib/BLI_kdopbvh.h
@@ -332,6 +332,29 @@ extern const float bvhtree_kdop_axes[13][3];
 
 namespace blender {
 
+using BVHTree_RayCastCallback_CPP =
+    FunctionRef;
+
+inline void BLI_bvhtree_ray_cast_all_cpp(BVHTree &tree,
+                                         const float3 co,
+                                         const float3 dir,
+                                         float radius,
+                                         float hit_dist,
+                                         BVHTree_RayCastCallback_CPP fn)
+{
+  BLI_bvhtree_ray_cast_all(
+      &tree,
+      co,
+      dir,
+      radius,
+      hit_dist,
+      [](void *userdata, int index, const BVHTreeRay *ray, BVHTreeRayHit *hit) {
+        BVHTree_RayCastCallback_CPP fn = *static_cast(userdata);
+        fn(index, *ray, *hit);
+      },
+      &fn);
+}
+
 using BVHTree_RangeQuery_CPP = FunctionRef;
 
 inline void BLI_bvhtree_range_query_cpp(BVHTree &tree,
diff --git a/source/blender/blenlib/BLI_lazy_threading.hh b/source/blender/blenlib/BLI_lazy_threading.hh
new file mode 100644
index 00000000000..b5a15919c89
--- /dev/null
+++ b/source/blender/blenlib/BLI_lazy_threading.hh
@@ -0,0 +1,83 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#pragma once
+
+/** \file
+ * \ingroup bli
+ *
+ * The goal of "lazy threading" is to avoid using threads unless one can reasonably assume that it
+ * is worth distributing work over multiple threads. Using threads can lead to worse overall
+ * performance by introducing inter-thread communication overhead. Keeping all work on a single
+ * thread reduces this overhead to zero and also makes better use of the CPU cache.
+ *
+ * Functions like #parallel_for also solve this to some degree by using a "grain size". When the
+ * number of individual tasks is too small, no multi-threading is used. This works very well when
+ * there are many homogeneous tasks that can be expected to take approximately the same time.
+ *
+ * The situation becomes more difficult when:
+ * - The individual tasks are not homogeneous, i.e. they take different amounts of time to compute.
+ * - It is practically impossible to guess how long each task will take in advance.
+ *
+ * Given those constraints, a single grain size cannot be determined. One could just schedule all
+ * tasks individually but that would create a lot of overhead when the tasks happen to be very
+ * small. While TBB will keep all tasks on a single thread if the other threads are busy, if they
+ * are idle they will start stealing the work even if that's not beneficial for overall
+ * performance.
+ *
+ * This file provides a simple API that allows a task scheduler to properly handle tasks whose size
+ * is not known in advance. The key idea is this:
+ *
+ * > By default, all work stays on a single thread. If an individual task notices that it is about
+ * > start a computation that will take a while, it notifies the task scheduler further up on the
+ * > stack. The scheduler then allows other threads to take over other tasks that were originally
+ * > meant for the current thread.
+ *
+ * This way, when all tasks are small, no threading overhead has to be paid for. Whenever there is
+ * a task that keeps the current thread busy for a while, the other tasks are moved to a separate
+ * thread so that they can be executed without waiting for the long computation to finish.
+ *
+ * Consequently, the earlier a task knows during it execution that it will take a while, the
+ * better. That's because if it is blocking anyway, it's more efficient to move the other tasks to
+ * another thread earlier.
+ *
+ * To make this work, three things have to be solved:
+ * 1. The task scheduler has to be able to start single-threaded and become multi-threaded after
+ *    tasks have started executing. This has to be solved in the specific task scheduler.
+ * 2. There has to be a way for the currently running task to tell the task scheduler that it is
+ *    about to perform a computation that will take a while and that it would be reasonable to move
+ *    other tasks to other threads. This part is implemented in the API provided by this file.
+ * 3. Individual tasks have to decide when a computation is long enough to justify talking to the
+ *    scheduler. This is always based on heuristics that have to be fine tuned over time. One could
+ *    assume that this means adding new work-size checks to many parts in Blender, but that's
+ *    actually not necessary, because these checks exist already in the form of grain sizes passed
+ *    to e.g. #parallel_for. The assumption here is that when the task thinks the current work load
+ *    is big enough to justify using threads, it's also big enough to justify using another thread
+ *    for waiting tasks on the current thread.
+ */
+
+#include "BLI_function_ref.hh"
+
+namespace blender::lazy_threading {
+
+/**
+ * Tell task schedulers on the current thread that it is about to start a long computation
+ * and that other waiting tasks should better be moved to another thread if possible.
+ */
+void send_hint();
+
+/**
+ * Used by the task scheduler to receive hints from current tasks that they will take a while.
+ * This should only be allocated on the stack.
+ */
+class HintReceiver {
+ public:
+  /**
+   * The passed in function is called when a task signals that it will take a while.
+   * \note The function has to stay alive after the call to the constructor. So one must not pass a
+   * lambda directly into this constructor but store it in a separate variable on the stack first.
+   */
+  HintReceiver(FunctionRef fn);
+  ~HintReceiver();
+};
+
+}  // namespace blender::lazy_threading
diff --git a/source/blender/blenlib/BLI_length_parameterize.hh b/source/blender/blenlib/BLI_length_parameterize.hh
index c44bb94f65d..d81bcbe1e7a 100644
--- a/source/blender/blenlib/BLI_length_parameterize.hh
+++ b/source/blender/blenlib/BLI_length_parameterize.hh
@@ -6,10 +6,10 @@
  * \ingroup bli
  */
 
+#include "BLI_index_mask.hh"
 #include "BLI_math_base.hh"
 #include "BLI_math_color.hh"
 #include "BLI_math_vector.hh"
-#include "BLI_vector.hh"
 
 namespace blender::length_parameterize {
 
@@ -42,26 +42,38 @@ void accumulate_lengths(const Span values, const bool cyclic, MutableSpan
-inline void linear_interpolation(const Span src,
-                                 const Span indices,
-                                 const Span factors,
-                                 MutableSpan dst)
+inline void interpolate_to_masked(const Span src,
+                                  const Span indices,
+                                  const Span factors,
+                                  const IndexMask dst_mask,
+                                  MutableSpan dst)
 {
   BLI_assert(indices.size() == factors.size());
-  BLI_assert(indices.size() == dst.size());
+  BLI_assert(indices.size() == dst_mask.size());
   const int last_src_index = src.size() - 1;
 
-  for (const int i : dst.index_range()) {
-    const int prev_index = indices[i];
-    const float factor = factors[i];
-    const bool is_cyclic_case = prev_index == last_src_index;
-    if (is_cyclic_case) {
-      dst[i] = math::interpolate(src.last(), src.first(), factor);
+  dst_mask.to_best_mask_type([&](auto dst_mask) {
+    for (const int i : IndexRange(dst_mask.size())) {
+      const int prev_index = indices[i];
+      const float factor = factors[i];
+      const bool is_cyclic_case = prev_index == last_src_index;
+      if (is_cyclic_case) {
+        dst[dst_mask[i]] = math::interpolate(src.last(), src.first(), factor);
+      }
+      else {
+        dst[dst_mask[i]] = math::interpolate(src[prev_index], src[prev_index + 1], factor);
+      }
     }
-    else {
-      dst[i] = math::interpolate(src[prev_index], src[prev_index + 1], factor);
-    }
-  }
+  });
+}
+
+template
+inline void interpolate(const Span src,
+                        const Span indices,
+                        const Span factors,
+                        MutableSpan dst)
+{
+  interpolate_to_masked(src, indices, factors, dst.index_range(), dst);
 }
 
 /**
@@ -75,6 +87,7 @@ struct SampleSegmentHint {
 
 /**
  * \param accumulated_segment_lengths: Lengths of individual segments added up.
+ * Each value describes the total length at the end of the segment following a point.
  * \param sample_length: The position to sample at.
  * \param r_segment_index: Returns the index of the segment that #sample_length is in.
  * \param r_factor: Returns the position within the segment.
@@ -82,7 +95,7 @@ struct SampleSegmentHint {
  * \note #sample_length must not be outside of any segment.
  */
 inline void sample_at_length(const Span accumulated_segment_lengths,
-                             float sample_length,
+                             const float sample_length,
                              int &r_segment_index,
                              float &r_factor,
                              SampleSegmentHint *hint = nullptr)
@@ -117,7 +130,7 @@ inline void sample_at_length(const Span accumulated_segment_lengths,
   const float segment_start = prev_point_index == 0 ? 0.0f : lengths[prev_point_index - 1];
   const float segment_end = lengths[prev_point_index];
   const float segment_length = segment_end - segment_start;
-  const float segment_length_inv = safe_divide(1.0f, segment_length);
+  const float segment_length_inv = math::safe_divide(1.0f, segment_length);
   const float length_in_segment = sample_length - segment_start;
   const float factor = length_in_segment * segment_length_inv;
 
diff --git a/source/blender/blenlib/BLI_listbase.h b/source/blender/blenlib/BLI_listbase.h
index 237fcdae8b9..6a41fce27b3 100644
--- a/source/blender/blenlib/BLI_listbase.h
+++ b/source/blender/blenlib/BLI_listbase.h
@@ -301,32 +301,33 @@ struct LinkData *BLI_genericNodeN(void *data);
  *
  * \code{.c}
  *
- * LISTBASE_CIRCULAR_FORWARD_BEGIN(listbase, item, item_init)
+ * LISTBASE_CIRCULAR_FORWARD_BEGIN(type, listbase, item, item_init)
  * {
  *     ...operate on marker...
  * }
- * LISTBASE_CIRCULAR_FORWARD_END (listbase, item, item_init);
+ * LISTBASE_CIRCULAR_FORWARD_END (type, listbase, item, item_init);
  *
  * \endcode
  */
-#define LISTBASE_CIRCULAR_FORWARD_BEGIN(lb, lb_iter, lb_init) \
-  if ((lb)->first && (lb_init || (lb_init = (lb)->first))) { \
-    lb_iter = lb_init; \
+#define LISTBASE_CIRCULAR_FORWARD_BEGIN(type, lb, lb_iter, lb_init) \
+  if ((lb)->first && (lb_init || (lb_init = (type)(lb)->first))) { \
+    lb_iter = (type)(lb_init); \
     do {
-#define LISTBASE_CIRCULAR_FORWARD_END(lb, lb_iter, lb_init) \
+#define LISTBASE_CIRCULAR_FORWARD_END(type, lb, lb_iter, lb_init) \
   } \
-  while ((lb_iter = (lb_iter)->next ? (lb_iter)->next : (lb)->first), (lb_iter != lb_init)) \
+  while ((lb_iter = (lb_iter)->next ? (type)(lb_iter)->next : (type)(lb)->first), \
+         (lb_iter != lb_init)) \
     ; \
   } \
   ((void)0)
 
-#define LISTBASE_CIRCULAR_BACKWARD_BEGIN(lb, lb_iter, lb_init) \
-  if ((lb)->last && (lb_init || (lb_init = (lb)->last))) { \
+#define LISTBASE_CIRCULAR_BACKWARD_BEGIN(type, lb, lb_iter, lb_init) \
+  if ((lb)->last && (lb_init || (lb_init = (type)(lb)->last))) { \
     lb_iter = lb_init; \
     do {
-#define LISTBASE_CIRCULAR_BACKWARD_END(lb, lb_iter, lb_init) \
+#define LISTBASE_CIRCULAR_BACKWARD_END(type, lb, lb_iter, lb_init) \
   } \
-  while ((lb_iter = (lb_iter)->prev ? (lb_iter)->prev : (lb)->last), (lb_iter != lb_init)) \
+  while ((lb_iter = (lb_iter)->prev ? (lb_iter)->prev : (type)(lb)->last), (lb_iter != lb_init)) \
     ; \
   } \
   ((void)0)
diff --git a/source/blender/blenlib/BLI_listbase_wrapper.hh b/source/blender/blenlib/BLI_listbase_wrapper.hh
index 25e029a5616..a32243bc411 100644
--- a/source/blender/blenlib/BLI_listbase_wrapper.hh
+++ b/source/blender/blenlib/BLI_listbase_wrapper.hh
@@ -42,7 +42,7 @@ template class ListBaseWrapper {
 
     Iterator &operator++()
     {
-      /* Some types store next/prev using `void *`, so cast is necessary. */
+      /* Some types store `next/prev` using `void *`, so cast is necessary. */
       current_ = static_cast(current_->next);
       return *this;
     }
@@ -50,7 +50,7 @@ template class ListBaseWrapper {
     Iterator operator++(int)
     {
       Iterator iterator = *this;
-      ++*this;
+      ++(*this);
       return iterator;
     }
 
diff --git a/source/blender/blenlib/BLI_map.hh b/source/blender/blenlib/BLI_map.hh
index 55233676ed8..95d1e344894 100644
--- a/source/blender/blenlib/BLI_map.hh
+++ b/source/blender/blenlib/BLI_map.hh
@@ -669,10 +669,10 @@ class Map {
       return *this;
     }
 
-    BaseIterator operator++(int) const
+    BaseIterator operator++(int)
     {
       BaseIterator copied_iterator = *this;
-      ++copied_iterator;
+      ++(*this);
       return copied_iterator;
     }
 
diff --git a/source/blender/blenlib/BLI_math_color.h b/source/blender/blenlib/BLI_math_color.h
index 6386a7f76f8..3aa2e35476d 100644
--- a/source/blender/blenlib/BLI_math_color.h
+++ b/source/blender/blenlib/BLI_math_color.h
@@ -164,7 +164,9 @@ void rgba_float_to_uchar(unsigned char r_col[4], const float col_f[4]);
 MINLINE float rgb_to_grayscale(const float rgb[3]);
 MINLINE unsigned char rgb_to_grayscale_byte(const unsigned char rgb[3]);
 
-MINLINE int compare_rgb_uchar(const unsigned char a[3], const unsigned char b[3], int limit);
+MINLINE int compare_rgb_uchar(const unsigned char col_a[3],
+                              const unsigned char col_b[3],
+                              int limit);
 
 /**
  * Return triangle noise in [-0.5..1.5] range.
diff --git a/source/blender/blenlib/BLI_math_geom.h b/source/blender/blenlib/BLI_math_geom.h
index 93b413ab755..d056c42e019 100644
--- a/source/blender/blenlib/BLI_math_geom.h
+++ b/source/blender/blenlib/BLI_math_geom.h
@@ -1270,8 +1270,8 @@ MINLINE void mul_sh_fl(float r[9], float f);
 MINLINE void add_sh_shsh(float r[9], const float a[9], const float b[9]);
 MINLINE float dot_shsh(const float a[9], const float b[9]);
 
-MINLINE float eval_shv3(float r[9], const float v[3]);
-MINLINE float diffuse_shv3(const float r[9], const float v[3]);
+MINLINE float eval_shv3(float sh[9], const float v[3]);
+MINLINE float diffuse_shv3(const float sh[9], const float v[3]);
 MINLINE void vec_fac_to_sh(float r[9], const float v[3], float f);
 MINLINE void madd_sh_shfl(float r[9], const float sh[9], float f);
 
diff --git a/source/blender/blenlib/BLI_math_matrix.h b/source/blender/blenlib/BLI_math_matrix.h
index 2cd2a299d53..19943614881 100644
--- a/source/blender/blenlib/BLI_math_matrix.h
+++ b/source/blender/blenlib/BLI_math_matrix.h
@@ -98,110 +98,110 @@ void mul_m4_m4_post(float R[4][4], const float B[4][4]);
 
 /* Implement #mul_m3_series macro. */
 
-void _va_mul_m3_series_3(float R[3][3], const float M1[3][3], const float M2[3][3]) ATTR_NONNULL();
-void _va_mul_m3_series_4(float R[3][3],
-                         const float M1[3][3],
-                         const float M2[3][3],
-                         const float M3[3][3]) ATTR_NONNULL();
-void _va_mul_m3_series_5(float R[3][3],
-                         const float M1[3][3],
-                         const float M2[3][3],
-                         const float M3[3][3],
-                         const float M4[3][3]) ATTR_NONNULL();
-void _va_mul_m3_series_6(float R[3][3],
-                         const float M1[3][3],
-                         const float M2[3][3],
-                         const float M3[3][3],
-                         const float M4[3][3],
-                         const float M5[3][3]) ATTR_NONNULL();
-void _va_mul_m3_series_7(float R[3][3],
-                         const float M1[3][3],
-                         const float M2[3][3],
-                         const float M3[3][3],
-                         const float M4[3][3],
-                         const float M5[3][3],
-                         const float M6[3][3]) ATTR_NONNULL();
-void _va_mul_m3_series_8(float R[3][3],
-                         const float M1[3][3],
-                         const float M2[3][3],
-                         const float M3[3][3],
-                         const float M4[3][3],
-                         const float M5[3][3],
-                         const float M6[3][3],
-                         const float M7[3][3]) ATTR_NONNULL();
-void _va_mul_m3_series_9(float R[3][3],
-                         const float M1[3][3],
-                         const float M2[3][3],
-                         const float M3[3][3],
-                         const float M4[3][3],
-                         const float M5[3][3],
-                         const float M6[3][3],
-                         const float M7[3][3],
-                         const float M8[3][3]) ATTR_NONNULL();
+void _va_mul_m3_series_3(float r[3][3], const float m1[3][3], const float m2[3][3]) ATTR_NONNULL();
+void _va_mul_m3_series_4(float r[3][3],
+                         const float m1[3][3],
+                         const float m2[3][3],
+                         const float m3[3][3]) ATTR_NONNULL();
+void _va_mul_m3_series_5(float r[3][3],
+                         const float m1[3][3],
+                         const float m2[3][3],
+                         const float m3[3][3],
+                         const float m4[3][3]) ATTR_NONNULL();
+void _va_mul_m3_series_6(float r[3][3],
+                         const float m1[3][3],
+                         const float m2[3][3],
+                         const float m3[3][3],
+                         const float m4[3][3],
+                         const float m5[3][3]) ATTR_NONNULL();
+void _va_mul_m3_series_7(float r[3][3],
+                         const float m1[3][3],
+                         const float m2[3][3],
+                         const float m3[3][3],
+                         const float m4[3][3],
+                         const float m5[3][3],
+                         const float m6[3][3]) ATTR_NONNULL();
+void _va_mul_m3_series_8(float r[3][3],
+                         const float m1[3][3],
+                         const float m2[3][3],
+                         const float m3[3][3],
+                         const float m4[3][3],
+                         const float m5[3][3],
+                         const float m6[3][3],
+                         const float m7[3][3]) ATTR_NONNULL();
+void _va_mul_m3_series_9(float r[3][3],
+                         const float m1[3][3],
+                         const float m2[3][3],
+                         const float m3[3][3],
+                         const float m4[3][3],
+                         const float m5[3][3],
+                         const float m6[3][3],
+                         const float m7[3][3],
+                         const float m8[3][3]) ATTR_NONNULL();
 
 /* Implement #mul_m4_series macro. */
 
-void _va_mul_m4_series_3(float R[4][4], const float M1[4][4], const float M2[4][4]) ATTR_NONNULL();
-void _va_mul_m4_series_4(float R[4][4],
-                         const float M1[4][4],
-                         const float M2[4][4],
-                         const float M3[4][4]) ATTR_NONNULL();
-void _va_mul_m4_series_5(float R[4][4],
-                         const float M1[4][4],
-                         const float M2[4][4],
-                         const float M3[4][4],
-                         const float M4[4][4]) ATTR_NONNULL();
-void _va_mul_m4_series_6(float R[4][4],
-                         const float M1[4][4],
-                         const float M2[4][4],
-                         const float M3[4][4],
-                         const float M4[4][4],
-                         const float M5[4][4]) ATTR_NONNULL();
-void _va_mul_m4_series_7(float R[4][4],
-                         const float M1[4][4],
-                         const float M2[4][4],
-                         const float M3[4][4],
-                         const float M4[4][4],
-                         const float M5[4][4],
-                         const float M6[4][4]) ATTR_NONNULL();
-void _va_mul_m4_series_8(float R[4][4],
-                         const float M1[4][4],
-                         const float M2[4][4],
-                         const float M3[4][4],
-                         const float M4[4][4],
-                         const float M5[4][4],
-                         const float M6[4][4],
-                         const float M7[4][4]) ATTR_NONNULL();
-void _va_mul_m4_series_9(float R[4][4],
-                         const float M1[4][4],
-                         const float M2[4][4],
-                         const float M3[4][4],
-                         const float M4[4][4],
-                         const float M5[4][4],
-                         const float M6[4][4],
-                         const float M7[4][4],
-                         const float M8[4][4]) ATTR_NONNULL();
+void _va_mul_m4_series_3(float r[4][4], const float m1[4][4], const float m2[4][4]) ATTR_NONNULL();
+void _va_mul_m4_series_4(float r[4][4],
+                         const float m1[4][4],
+                         const float m2[4][4],
+                         const float m3[4][4]) ATTR_NONNULL();
+void _va_mul_m4_series_5(float r[4][4],
+                         const float m1[4][4],
+                         const float m2[4][4],
+                         const float m3[4][4],
+                         const float m4[4][4]) ATTR_NONNULL();
+void _va_mul_m4_series_6(float r[4][4],
+                         const float m1[4][4],
+                         const float m2[4][4],
+                         const float m3[4][4],
+                         const float m4[4][4],
+                         const float m5[4][4]) ATTR_NONNULL();
+void _va_mul_m4_series_7(float r[4][4],
+                         const float m1[4][4],
+                         const float m2[4][4],
+                         const float m3[4][4],
+                         const float m4[4][4],
+                         const float m5[4][4],
+                         const float m6[4][4]) ATTR_NONNULL();
+void _va_mul_m4_series_8(float r[4][4],
+                         const float m1[4][4],
+                         const float m2[4][4],
+                         const float m3[4][4],
+                         const float m4[4][4],
+                         const float m5[4][4],
+                         const float m6[4][4],
+                         const float m7[4][4]) ATTR_NONNULL();
+void _va_mul_m4_series_9(float r[4][4],
+                         const float m1[4][4],
+                         const float m2[4][4],
+                         const float m3[4][4],
+                         const float m4[4][4],
+                         const float m5[4][4],
+                         const float m6[4][4],
+                         const float m7[4][4],
+                         const float m8[4][4]) ATTR_NONNULL();
 
 #define mul_m3_series(...) VA_NARGS_CALL_OVERLOAD(_va_mul_m3_series_, __VA_ARGS__)
 #define mul_m4_series(...) VA_NARGS_CALL_OVERLOAD(_va_mul_m4_series_, __VA_ARGS__)
 
 void mul_m4_v3(const float M[4][4], float r[3]);
-void mul_v3_m4v3(float r[3], const float M[4][4], const float v[3]);
+void mul_v3_m4v3(float r[3], const float mat[4][4], const float vec[3]);
 void mul_v3_m4v3_db(double r[3], const double mat[4][4], const double vec[3]);
 void mul_v4_m4v3_db(double r[4], const double mat[4][4], const double vec[3]);
-void mul_v2_m4v3(float r[2], const float M[4][4], const float v[3]);
-void mul_v2_m2v2(float r[2], const float M[2][2], const float v[2]);
-void mul_m2_v2(const float M[2][2], float v[2]);
+void mul_v2_m4v3(float r[2], const float mat[4][4], const float vec[3]);
+void mul_v2_m2v2(float r[2], const float mat[2][2], const float vec[2]);
+void mul_m2_v2(const float mat[2][2], float vec[2]);
 /** Same as #mul_m4_v3() but doesn't apply translation component. */
-void mul_mat3_m4_v3(const float M[4][4], float r[3]);
-void mul_v3_mat3_m4v3(float r[3], const float M[4][4], const float v[3]);
-void mul_v3_mat3_m4v3_db(double r[3], const double M[4][4], const double v[3]);
-void mul_m4_v4(const float M[4][4], float r[4]);
-void mul_v4_m4v4(float r[4], const float M[4][4], const float v[4]);
+void mul_mat3_m4_v3(const float mat[4][4], float r[3]);
+void mul_v3_mat3_m4v3(float r[3], const float mat[4][4], const float vec[3]);
+void mul_v3_mat3_m4v3_db(double r[3], const double mat[4][4], const double vec[3]);
+void mul_m4_v4(const float mat[4][4], float r[4]);
+void mul_v4_m4v4(float r[4], const float mat[4][4], const float v[4]);
 void mul_v4_m4v3(float r[4], const float M[4][4], const float v[3]); /* v has implicit w = 1.0f */
-void mul_project_m4_v3(const float M[4][4], float vec[3]);
+void mul_project_m4_v3(const float mat[4][4], float vec[3]);
 void mul_v3_project_m4_v3(float r[3], const float mat[4][4], const float vec[3]);
-void mul_v2_project_m4_v3(float r[2], const float M[4][4], const float vec[3]);
+void mul_v2_project_m4_v3(float r[2], const float mat[4][4], const float vec[3]);
 
 void mul_m3_v2(const float m[3][3], float r[2]);
 void mul_v2_m3v2(float r[2], const float m[3][3], const float v[2]);
@@ -234,13 +234,14 @@ void negate_m3(float R[3][3]);
 void negate_mat3_m4(float R[4][4]);
 void negate_m4(float R[4][4]);
 
-bool invert_m3_ex(float m[3][3], float epsilon);
-bool invert_m3_m3_ex(float m1[3][3], const float m2[3][3], float epsilon);
+bool invert_m3_ex(float mat[3][3], float epsilon);
+bool invert_m3_m3_ex(float inverse[3][3], const float mat[3][3], float epsilon);
 
-bool invert_m3(float R[3][3]);
-bool invert_m3_m3(float R[3][3], const float A[3][3]);
-bool invert_m4(float R[4][4]);
-bool invert_m4_m4(float R[4][4], const float A[4][4]);
+bool invert_m3(float mat[3][3]);
+bool invert_m2_m2(float inverse[2][2], const float mat[2][2]);
+bool invert_m3_m3(float inverse[3][3], const float mat[3][3]);
+bool invert_m4(float mat[4][4]);
+bool invert_m4_m4(float inverse[4][4], const float mat[4][4]);
 /**
  * Computes the inverse of mat and puts it in inverse.
  * Uses Gaussian Elimination with partial (maximal column) pivoting.
@@ -251,12 +252,12 @@ bool invert_m4_m4(float R[4][4], const float A[4][4]);
  * for non-invertible scale matrices, finding a partial solution can
  * be useful to have a valid local transform center, see T57767.
  */
-bool invert_m4_m4_fallback(float R[4][4], const float A[4][4]);
+bool invert_m4_m4_fallback(float inverse[4][4], const float mat[4][4]);
 
 /* Double arithmetic (mixed float/double). */
 
-void mul_m4_v4d(const float M[4][4], double r[4]);
-void mul_v4d_m4v4d(double r[4], const float M[4][4], const double v[4]);
+void mul_m4_v4d(const float mat[4][4], double r[4]);
+void mul_v4d_m4v4d(double r[4], const float mat[4][4], const double v[4]);
 
 /* Double matrix functions (no mixing types). */
 
@@ -290,8 +291,8 @@ void normalize_m3_m3_ex(float R[3][3], const float M[3][3], float r_scale[3]) AT
 void normalize_m3_m3(float R[3][3], const float M[3][3]) ATTR_NONNULL();
 void normalize_m4_ex(float R[4][4], float r_scale[3]) ATTR_NONNULL();
 void normalize_m4(float R[4][4]) ATTR_NONNULL();
-void normalize_m4_m4_ex(float R[4][4], const float M[4][4], float r_scale[3]) ATTR_NONNULL();
-void normalize_m4_m4(float R[4][4], const float M[4][4]) ATTR_NONNULL();
+void normalize_m4_m4_ex(float rmat[4][4], const float mat[4][4], float r_scale[3]) ATTR_NONNULL();
+void normalize_m4_m4(float rmat[4][4], const float mat[4][4]) ATTR_NONNULL();
 
 /**
  * Make an orthonormal matrix around the selected axis of the given matrix.
@@ -325,15 +326,15 @@ void orthogonalize_m3_stable(float R[3][3], int axis, bool normalize);
  */
 void orthogonalize_m4_stable(float R[4][4], int axis, bool normalize);
 
-bool orthogonalize_m3_zero_axes(float R[3][3], float unit_length);
-bool orthogonalize_m4_zero_axes(float R[4][4], float unit_length);
+bool orthogonalize_m3_zero_axes(float m[3][3], float unit_length);
+bool orthogonalize_m4_zero_axes(float m[4][4], float unit_length);
 
-bool is_orthogonal_m3(const float mat[3][3]);
-bool is_orthogonal_m4(const float mat[4][4]);
-bool is_orthonormal_m3(const float mat[3][3]);
-bool is_orthonormal_m4(const float mat[4][4]);
+bool is_orthogonal_m3(const float m[3][3]);
+bool is_orthogonal_m4(const float m[4][4]);
+bool is_orthonormal_m3(const float m[3][3]);
+bool is_orthonormal_m4(const float m[4][4]);
 
-bool is_uniform_scaled_m3(const float mat[3][3]);
+bool is_uniform_scaled_m3(const float m[3][3]);
 bool is_uniform_scaled_m4(const float m[4][4]);
 
 /* NOTE: 'adjoint' here means the adjugate (adjunct, "classical adjoint") matrix!
@@ -361,22 +362,22 @@ float determinant_m4(const float m[4][4]);
  * From this decomposition it is trivial to compute the (pseudo-inverse)
  * of `A` as `Ainv = V.Winv.transpose(U)`.
  */
-void svd_m4(float U[4][4], float s[4], float V[4][4], float A[4][4]);
-void pseudoinverse_m4_m4(float Ainv[4][4], const float A[4][4], float epsilon);
-void pseudoinverse_m3_m3(float Ainv[3][3], const float A[3][3], float epsilon);
+void svd_m4(float U[4][4], float s[4], float V[4][4], float A_[4][4]);
+void pseudoinverse_m4_m4(float inverse[4][4], const float mat[4][4], float epsilon);
+void pseudoinverse_m3_m3(float inverse[3][3], const float mat[3][3], float epsilon);
 
 bool has_zero_axis_m4(const float matrix[4][4]);
 
-void invert_m4_m4_safe(float Ainv[4][4], const float A[4][4]);
+void invert_m4_m4_safe(float inverse[4][4], const float mat[4][4]);
 
-void invert_m3_m3_safe_ortho(float Ainv[3][3], const float A[3][3]);
+void invert_m3_m3_safe_ortho(float inverse[3][3], const float mat[3][3]);
 /**
  * A safe version of invert that uses valid axes, calculating the zero'd axis
  * based on the non-zero ones.
  *
  * This works well for transformation matrices, when a single axis is zeroed.
  */
-void invert_m4_m4_safe_ortho(float Ainv[4][4], const float A[4][4]);
+void invert_m4_m4_safe_ortho(float inverse[4][4], const float mat[4][4]);
 
 /** \} */
 
@@ -393,22 +394,24 @@ void scale_m4_v2(float R[4][4], const float scale[2]);
  * For an orthogonal matrix, it is the product of all three scale values.
  * Returns a negative value if the transform is flipped by negative scale.
  */
-float mat3_to_volume_scale(const float M[3][3]);
-float mat4_to_volume_scale(const float M[4][4]);
+float mat3_to_volume_scale(const float mat[3][3]);
+float mat4_to_volume_scale(const float mat[4][4]);
 
 /**
  * This gets the average scale of a matrix, only use when your scaling
  * data that has no idea of scale axis, examples are bone-envelope-radius
  * and curve radius.
  */
-float mat3_to_scale(const float M[3][3]);
-float mat4_to_scale(const float M[4][4]);
+float mat3_to_scale(const float mat[3][3]);
+float mat4_to_scale(const float mat[4][4]);
 /** Return 2D scale (in XY plane) of given mat4. */
-float mat4_to_xy_scale(const float M[4][4]);
+float mat4_to_xy_scale(const float mat[4][4]);
 
 void size_to_mat3(float R[3][3], const float size[3]);
 void size_to_mat4(float R[4][4], const float size[3]);
 
+/** Return 2D size assuming the given matrix is a 2D affine matrix. */
+void mat3_to_size_2d(float size[2], const float M[3][3]);
 void mat3_to_size(float size[3], const float M[3][3]);
 void mat4_to_size(float size[3], const float M[4][4]);
 
@@ -432,7 +435,7 @@ float mat4_to_size_max_axis(const float M[4][4]);
  */
 void mat4_to_size_fix_shear(float size[3], const float M[4][4]);
 
-void translate_m4(float mat[4][4], float tx, float ty, float tz);
+void translate_m4(float mat[4][4], float Tx, float Ty, float Tz);
 /**
  * Rotate a matrix in-place.
  *
@@ -453,8 +456,20 @@ void rescale_m4(float mat[4][4], const float scale[3]);
  */
 void transform_pivot_set_m4(float mat[4][4], const float pivot[3]);
 
+/**
+ * \param rot: A 3x3 rotation matrix, normalized never negative.
+ */
 void mat4_to_rot(float rot[3][3], const float wmat[4][4]);
+
+/**
+ * \param rot: A 3x3 rotation matrix, normalized never negative.
+ * \param size: The scale, negative if `mat3` is negative.
+ */
 void mat3_to_rot_size(float rot[3][3], float size[3], const float mat3[3][3]);
+/**
+ * \param rot: A 3x3 rotation matrix, normalized never negative.
+ * \param size: The scale, negative if `mat3` is negative.
+ */
 void mat4_to_loc_rot_size(float loc[3], float rot[3][3], float size[3], const float wmat[4][4]);
 void mat4_to_loc_quat(float loc[3], float quat[4], const float wmat[4][4]);
 void mat4_decompose(float loc[3], float quat[4], float size[3], const float wmat[4][4]);
@@ -527,7 +542,18 @@ void interp_m3_m3m3(float R[3][3], const float A[3][3], const float B[3][3], flo
  */
 void interp_m4_m4m4(float R[4][4], const float A[4][4], const float B[4][4], float t);
 
+/**
+ * Return true when the matrices determinant is less than zero.
+ *
+ * \note This is often used to check if a matrix flips content in 3D space,
+ * where transforming geometry (for example) would flip the direction of polygon normals
+ * from pointing outside a closed volume, to pointing inside (or the reverse).
+ *
+ * When the matrix is constructed from location, rotation & scale
+ * as matrix will be negative when it has an odd number of negative scales.
+ */
 bool is_negative_m3(const float mat[3][3]);
+/** A version of #is_negative_m3 that takes a 4x4 matrix. */
 bool is_negative_m4(const float mat[4][4]);
 
 bool is_zero_m3(const float mat[3][3]);
@@ -604,8 +630,8 @@ void BLI_space_transform_invert_normal(const struct SpaceTransform *data, float
 /** \name Other
  * \{ */
 
-void print_m3(const char *str, const float M[3][3]);
-void print_m4(const char *str, const float M[4][4]);
+void print_m3(const char *str, const float m[3][3]);
+void print_m4(const char *str, const float m[4][4]);
 
 #define print_m3_id(M) print_m3(STRINGIFY(M), M)
 #define print_m4_id(M) print_m4(STRINGIFY(M), M)
diff --git a/source/blender/blenlib/BLI_math_rotation.h b/source/blender/blenlib/BLI_math_rotation.h
index 192ad482a69..7fb7085360b 100644
--- a/source/blender/blenlib/BLI_math_rotation.h
+++ b/source/blender/blenlib/BLI_math_rotation.h
@@ -71,7 +71,7 @@ void mul_qt_fl(float q[4], float f);
 /**
  * Raise a unit quaternion to the specified power.
  */
-void pow_qt_fl_normalized(float q[4], float f);
+void pow_qt_fl_normalized(float q[4], float fac);
 
 void sub_qt_qtqt(float q[4], const float a[4], const float b[4]);
 
@@ -109,8 +109,8 @@ void add_qt_qtqt(float q[4], const float a[4], const float b[4], float t);
 
 /* Conversion. */
 
-void quat_to_mat3(float mat[3][3], const float q[4]);
-void quat_to_mat4(float mat[4][4], const float q[4]);
+void quat_to_mat3(float m[3][3], const float q[4]);
+void quat_to_mat4(float m[4][4], const float q[4]);
 
 /**
  * Apply the rotation of \a a to \a q keeping the values compatible with \a old.
@@ -118,6 +118,11 @@ void quat_to_mat4(float mat[4][4], const float q[4]);
  */
 void quat_to_compatible_quat(float q[4], const float a[4], const float old[4]);
 
+/**
+ * A version of #mat3_normalized_to_quat that skips error checking.
+ */
+void mat3_normalized_to_quat_fast(float q[4], const float mat[3][3]);
+
 void mat3_normalized_to_quat(float q[4], const float mat[3][3]);
 void mat4_normalized_to_quat(float q[4], const float mat[4][4]);
 void mat3_to_quat(float q[4], const float mat[3][3]);
@@ -157,7 +162,10 @@ void rotation_between_quats_to_quat(float q[4], const float q1[4], const float q
  * \param r_twist: if not NULL, receives the twist quaternion.
  * \returns twist angle.
  */
-float quat_split_swing_and_twist(const float q[4], int axis, float r_swing[4], float r_twist[4]);
+float quat_split_swing_and_twist(const float q_in[4],
+                                 int axis,
+                                 float r_swing[4],
+                                 float r_twist[4]);
 
 float angle_normalized_qt(const float q[4]);
 float angle_normalized_qtqt(const float q1[4], const float q2[4]);
@@ -170,12 +178,32 @@ float angle_signed_qt(const float q[4]);
 float angle_signed_qtqt(const float q1[4], const float q2[4]);
 
 /**
- * TODO: don't what this is, but it's not the same as #mat3_to_quat.
+ * Legacy matrix to quaternion conversion, keep to prevent changes to existing
+ * boids & particle-system behavior. Use #mat3_to_quat for new code.
  */
-void mat3_to_quat_is_ok(float q[4], const float mat[3][3]);
+void mat3_to_quat_legacy(float q[4], const float wmat[3][3]);
 
 /* Other. */
 
+/**
+ * Utility that performs `sinf` & `cosf` intended for plotting a 2D circle,
+ * where the values of the coordinates with are exactly symmetrical although this
+ * favors even numbers as odd numbers can only be symmetrical on a single axis.
+ *
+ * Besides adjustments to precision, this function is the equivalent of:
+ * \code {.c}
+ * float phi = (2 * M_PI) * (float)i / (float)denominator;
+ * *r_sin = sinf(phi);
+ * *r_cos = cosf(phi);
+ * \endcode
+ *
+ * \param numerator: An integer factor in [0..denominator] (inclusive).
+ * \param denominator: The fraction denominator (typically the number of segments of the circle).
+ * \param r_sin: The resulting sine.
+ * \param r_cos: The resulting cosine.
+ */
+void sin_cos_from_fraction(int numerator, int denominator, float *r_sin, float *r_cos);
+
 void print_qt(const char *str, const float q[4]);
 
 #define print_qt_id(q) print_qt(STRINGIFY(q), q)
@@ -216,16 +244,16 @@ void axis_angle_to_mat4(float R[4][4], const float axis[3], float angle);
 /**
  * 3x3 matrix to axis angle.
  */
-void mat3_normalized_to_axis_angle(float axis[3], float *angle, const float M[3][3]);
+void mat3_normalized_to_axis_angle(float axis[3], float *angle, const float mat[3][3]);
 /**
  * 4x4 matrix to axis angle.
  */
-void mat4_normalized_to_axis_angle(float axis[3], float *angle, const float M[4][4]);
-void mat3_to_axis_angle(float axis[3], float *angle, const float M[3][3]);
+void mat4_normalized_to_axis_angle(float axis[3], float *angle, const float mat[4][4]);
+void mat3_to_axis_angle(float axis[3], float *angle, const float mat[3][3]);
 /**
  * 4x4 matrix to axis angle.
  */
-void mat4_to_axis_angle(float axis[3], float *angle, const float M[4][4]);
+void mat4_to_axis_angle(float axis[3], float *angle, const float mat[4][4]);
 /**
  * Quaternions to Axis Angle.
  */
@@ -264,19 +292,19 @@ void eul_to_mat3(float mat[3][3], const float eul[3]);
 void eul_to_mat4(float mat[4][4], const float eul[3]);
 
 void mat3_normalized_to_eul(float eul[3], const float mat[3][3]);
-void mat4_normalized_to_eul(float eul[3], const float mat[4][4]);
+void mat4_normalized_to_eul(float eul[3], const float m[4][4]);
 void mat3_to_eul(float eul[3], const float mat[3][3]);
 void mat4_to_eul(float eul[3], const float mat[4][4]);
 void quat_to_eul(float eul[3], const float quat[4]);
 
-void mat3_normalized_to_compatible_eul(float eul[3], const float old[3], float mat[3][3]);
-void mat3_to_compatible_eul(float eul[3], const float old[3], float mat[3][3]);
+void mat3_normalized_to_compatible_eul(float eul[3], const float oldrot[3], float mat[3][3]);
+void mat3_to_compatible_eul(float eul[3], const float oldrot[3], float mat[3][3]);
 void quat_to_compatible_eul(float eul[3], const float oldrot[3], const float quat[4]);
-void rotate_eul(float eul[3], char axis, float angle);
+void rotate_eul(float beul[3], char axis, float angle);
 
 /* Order independent. */
 
-void compatible_eul(float eul[3], const float old[3]);
+void compatible_eul(float eul[3], const float oldrot[3]);
 
 void add_eul_euleul(float r_eul[3], float a[3], float b[3], short order);
 void sub_eul_euleul(float r_eul[3], float a[3], float b[3], short order);
@@ -304,15 +332,15 @@ typedef enum eEulerRotationOrders {
 /**
  * Construct quaternion from Euler angles (in radians).
  */
-void eulO_to_quat(float quat[4], const float eul[3], short order);
+void eulO_to_quat(float q[4], const float e[3], short order);
 /**
  * Construct 3x3 matrix from Euler angles (in radians).
  */
-void eulO_to_mat3(float mat[3][3], const float eul[3], short order);
+void eulO_to_mat3(float M[3][3], const float e[3], short order);
 /**
  * Construct 4x4 matrix from Euler angles (in radians).
  */
-void eulO_to_mat4(float mat[4][4], const float eul[3], short order);
+void eulO_to_mat4(float mat[4][4], const float e[3], short order);
 /**
  * Euler Rotation to Axis Angle.
  */
@@ -325,17 +353,17 @@ void eulO_to_gimbal_axis(float gmat[3][3], const float eul[3], short order);
 /**
  * Convert 3x3 matrix to Euler angles (in radians).
  */
-void mat3_normalized_to_eulO(float eul[3], short order, const float mat[3][3]);
+void mat3_normalized_to_eulO(float eul[3], short order, const float m[3][3]);
 /**
  * Convert 4x4 matrix to Euler angles (in radians).
  */
-void mat4_normalized_to_eulO(float eul[3], short order, const float mat[4][4]);
-void mat3_to_eulO(float eul[3], short order, const float mat[3][3]);
-void mat4_to_eulO(float eul[3], short order, const float mat[4][4]);
+void mat4_normalized_to_eulO(float eul[3], short order, const float m[4][4]);
+void mat3_to_eulO(float eul[3], short order, const float m[3][3]);
+void mat4_to_eulO(float eul[3], short order, const float m[4][4]);
 /**
  * Convert quaternion to Euler angles (in radians).
  */
-void quat_to_eulO(float eul[3], short order, const float quat[4]);
+void quat_to_eulO(float e[3], short order, const float q[4]);
 /**
  * Axis Angle to Euler Rotation.
  */
@@ -344,18 +372,27 @@ void axis_angle_to_eulO(float eul[3], short order, const float axis[3], float an
 /* Uses 2 methods to retrieve eulers, and picks the closest. */
 
 void mat3_normalized_to_compatible_eulO(float eul[3],
-                                        const float old[3],
+                                        const float oldrot[3],
                                         short order,
                                         const float mat[3][3]);
 void mat4_normalized_to_compatible_eulO(float eul[3],
-                                        const float old[3],
+                                        const float oldrot[3],
                                         short order,
                                         const float mat[4][4]);
-void mat3_to_compatible_eulO(float eul[3], const float old[3], short order, const float mat[3][3]);
-void mat4_to_compatible_eulO(float eul[3], const float old[3], short order, const float mat[4][4]);
-void quat_to_compatible_eulO(float eul[3], const float old[3], short order, const float quat[4]);
-
-void rotate_eulO(float eul[3], short order, char axis, float angle);
+void mat3_to_compatible_eulO(float eul[3],
+                             const float oldrot[3],
+                             short order,
+                             const float mat[3][3]);
+void mat4_to_compatible_eulO(float eul[3],
+                             const float oldrot[3],
+                             short order,
+                             const float mat[4][4]);
+void quat_to_compatible_eulO(float eul[3],
+                             const float oldrot[3],
+                             short order,
+                             const float quat[4]);
+
+void rotate_eulO(float beul[3], short order, char axis, float angle);
 
 /** \} */
 
@@ -364,7 +401,7 @@ void rotate_eulO(float eul[3], short order, char axis, float angle);
  * \{ */
 
 void copy_dq_dq(DualQuat *r, const DualQuat *dq);
-void normalize_dq(DualQuat *dq, float totw);
+void normalize_dq(DualQuat *dq, float totweight);
 void add_weighted_dq_dq(DualQuat *dq_sum, const DualQuat *dq, float weight);
 void mul_v3m3_dq(float r[3], float R[3][3], DualQuat *dq);
 
@@ -381,7 +418,7 @@ void vec_apply_track(float vec[3], short axis);
  * Lens/angle conversion (radians).
  */
 float focallength_to_fov(float focal_length, float sensor);
-float fov_to_focallength(float fov, float sensor);
+float fov_to_focallength(float hfov, float sensor);
 
 float angle_wrap_rad(float angle);
 float angle_wrap_deg(float angle);
diff --git a/source/blender/blenlib/BLI_math_rotation.hh b/source/blender/blenlib/BLI_math_rotation.hh
index e8b746b34df..50a062162ad 100644
--- a/source/blender/blenlib/BLI_math_rotation.hh
+++ b/source/blender/blenlib/BLI_math_rotation.hh
@@ -15,4 +15,13 @@ namespace blender::math {
  */
 float3 rotate_direction_around_axis(const float3 &direction, const float3 &axis, float angle);
 
+/**
+ * Rotate any arbitrary \a vector around the \a center position, with a unit-length \a axis
+ * and the specified \a angle.
+ */
+float3 rotate_around_axis(const float3 &vector,
+                          const float3 ¢er,
+                          const float3 &axis,
+                          float angle);
+
 }  // namespace blender::math
diff --git a/source/blender/blenlib/BLI_math_vector.h b/source/blender/blenlib/BLI_math_vector.h
index 0b178064a4c..17fe25ec67b 100644
--- a/source/blender/blenlib/BLI_math_vector.h
+++ b/source/blender/blenlib/BLI_math_vector.h
@@ -155,7 +155,7 @@ MINLINE void mul_v3_v3db_db(double r[3], const double a[3], double f);
 MINLINE void mul_v2_v2(float r[2], const float a[2]);
 MINLINE void mul_v2_v2v2(float r[2], const float a[2], const float b[2]);
 MINLINE void mul_v3_v3(float r[3], const float a[3]);
-MINLINE void mul_v3_v3v3(float r[3], const float a[3], const float b[3]);
+MINLINE void mul_v3_v3v3(float r[3], const float v1[3], const float v2[3]);
 MINLINE void mul_v4_fl(float r[4], float f);
 MINLINE void mul_v4_v4(float r[4], const float a[4]);
 MINLINE void mul_v4_v4fl(float r[4], const float a[4], float f);
@@ -271,10 +271,10 @@ MINLINE float len_squared_v3(const float v[3]) ATTR_WARN_UNUSED_RESULT;
 MINLINE float len_manhattan_v2(const float v[2]) ATTR_WARN_UNUSED_RESULT;
 MINLINE int len_manhattan_v2_int(const int v[2]) ATTR_WARN_UNUSED_RESULT;
 MINLINE float len_manhattan_v3(const float v[3]) ATTR_WARN_UNUSED_RESULT;
-MINLINE float len_v2(const float a[2]) ATTR_WARN_UNUSED_RESULT;
+MINLINE float len_v2(const float v[2]) ATTR_WARN_UNUSED_RESULT;
 MINLINE double len_v2_db(const double v[2]) ATTR_WARN_UNUSED_RESULT;
-MINLINE float len_v2v2(const float a[2], const float b[2]) ATTR_WARN_UNUSED_RESULT;
-MINLINE double len_v2v2_db(const double a[2], const double b[2]) ATTR_WARN_UNUSED_RESULT;
+MINLINE float len_v2v2(const float v1[2], const float v2[2]) ATTR_WARN_UNUSED_RESULT;
+MINLINE double len_v2v2_db(const double v1[2], const double v2[2]) ATTR_WARN_UNUSED_RESULT;
 MINLINE float len_v2v2_int(const int v1[2], const int v2[2]);
 MINLINE float len_squared_v2v2(const float a[2], const float b[2]) ATTR_WARN_UNUSED_RESULT;
 MINLINE double len_squared_v2v2_db(const double a[2], const double b[2]) ATTR_WARN_UNUSED_RESULT;
@@ -288,22 +288,22 @@ MINLINE float len_v3v3(const float a[3], const float b[3]) ATTR_WARN_UNUSED_RESU
 
 MINLINE double len_v3_db(const double a[3]) ATTR_WARN_UNUSED_RESULT;
 MINLINE double len_squared_v3_db(const double v[3]) ATTR_WARN_UNUSED_RESULT;
-MINLINE float normalize_v2_length(float r[2], float unit_scale);
+MINLINE float normalize_v2_length(float n[2], float unit_length);
 /**
  * \note any vectors containing `nan` will be zeroed out.
  */
-MINLINE float normalize_v2_v2_length(float r[2], const float a[2], float unit_scale);
-MINLINE float normalize_v3_length(float r[3], float unit_scale);
+MINLINE float normalize_v2_v2_length(float r[2], const float a[2], float unit_length);
+MINLINE float normalize_v3_length(float n[3], float unit_length);
 /**
  * \note any vectors containing `nan` will be zeroed out.
  */
-MINLINE float normalize_v3_v3_length(float r[3], const float a[3], float unit_scale);
-MINLINE double normalize_v3_length_db(double n[3], double unit_scale);
-MINLINE double normalize_v3_v3_length_db(double r[3], const double a[3], double unit_scale);
+MINLINE float normalize_v3_v3_length(float r[3], const float a[3], float unit_length);
+MINLINE double normalize_v3_length_db(double n[3], double unit_length);
+MINLINE double normalize_v3_v3_length_db(double r[3], const double a[3], double unit_length);
 
-MINLINE float normalize_v2(float r[2]);
+MINLINE float normalize_v2(float n[2]);
 MINLINE float normalize_v2_v2(float r[2], const float a[2]);
-MINLINE float normalize_v3(float r[3]);
+MINLINE float normalize_v3(float n[3]);
 MINLINE float normalize_v3_v3(float r[3], const float a[3]);
 MINLINE double normalize_v3_v3_db(double r[3], const double a[3]);
 MINLINE double normalize_v3_db(double n[3]);
@@ -424,45 +424,51 @@ void flip_v2_v2v2(float v[2], const float v1[2], const float v2[2]);
 /** \name Comparison
  * \{ */
 
-MINLINE bool is_zero_v2(const float a[2]) ATTR_WARN_UNUSED_RESULT;
-MINLINE bool is_zero_v3(const float a[3]) ATTR_WARN_UNUSED_RESULT;
-MINLINE bool is_zero_v4(const float a[4]) ATTR_WARN_UNUSED_RESULT;
+MINLINE bool is_zero_v2(const float v[2]) ATTR_WARN_UNUSED_RESULT;
+MINLINE bool is_zero_v3(const float v[3]) ATTR_WARN_UNUSED_RESULT;
+MINLINE bool is_zero_v4(const float v[4]) ATTR_WARN_UNUSED_RESULT;
 
-MINLINE bool is_zero_v2_db(const double a[2]) ATTR_WARN_UNUSED_RESULT;
-MINLINE bool is_zero_v3_db(const double a[3]) ATTR_WARN_UNUSED_RESULT;
-MINLINE bool is_zero_v4_db(const double a[4]) ATTR_WARN_UNUSED_RESULT;
+MINLINE bool is_zero_v2_db(const double v[2]) ATTR_WARN_UNUSED_RESULT;
+MINLINE bool is_zero_v3_db(const double v[3]) ATTR_WARN_UNUSED_RESULT;
+MINLINE bool is_zero_v4_db(const double v[4]) ATTR_WARN_UNUSED_RESULT;
 
-bool is_finite_v2(const float a[2]) ATTR_WARN_UNUSED_RESULT;
-bool is_finite_v3(const float a[3]) ATTR_WARN_UNUSED_RESULT;
-bool is_finite_v4(const float a[4]) ATTR_WARN_UNUSED_RESULT;
+bool is_finite_v2(const float v[2]) ATTR_WARN_UNUSED_RESULT;
+bool is_finite_v3(const float v[3]) ATTR_WARN_UNUSED_RESULT;
+bool is_finite_v4(const float v[4]) ATTR_WARN_UNUSED_RESULT;
 
-MINLINE bool is_one_v3(const float a[3]) ATTR_WARN_UNUSED_RESULT;
+MINLINE bool is_one_v3(const float v[3]) ATTR_WARN_UNUSED_RESULT;
 
 MINLINE bool equals_v2v2(const float v1[2], const float v2[2]) ATTR_WARN_UNUSED_RESULT;
-MINLINE bool equals_v3v3(const float a[3], const float b[3]) ATTR_WARN_UNUSED_RESULT;
-MINLINE bool equals_v4v4(const float a[4], const float b[4]) ATTR_WARN_UNUSED_RESULT;
+MINLINE bool equals_v3v3(const float v1[3], const float v2[3]) ATTR_WARN_UNUSED_RESULT;
+MINLINE bool equals_v4v4(const float v1[4], const float v2[4]) ATTR_WARN_UNUSED_RESULT;
 
 MINLINE bool equals_v2v2_int(const int v1[2], const int v2[2]) ATTR_WARN_UNUSED_RESULT;
 MINLINE bool equals_v3v3_int(const int v1[3], const int v2[3]) ATTR_WARN_UNUSED_RESULT;
 MINLINE bool equals_v4v4_int(const int v1[4], const int v2[4]) ATTR_WARN_UNUSED_RESULT;
 
-MINLINE bool compare_v2v2(const float a[2], const float b[2], float limit) ATTR_WARN_UNUSED_RESULT;
-MINLINE bool compare_v3v3(const float a[3], const float b[3], float limit) ATTR_WARN_UNUSED_RESULT;
-MINLINE bool compare_v4v4(const float a[4], const float b[4], float limit) ATTR_WARN_UNUSED_RESULT;
-
-MINLINE bool compare_v2v2_relative(const float a[2], const float b[2], float limit, int max_ulps)
+MINLINE bool compare_v2v2(const float v1[2],
+                          const float v2[2],
+                          float limit) ATTR_WARN_UNUSED_RESULT;
+MINLINE bool compare_v3v3(const float v1[3],
+                          const float v2[3],
+                          float limit) ATTR_WARN_UNUSED_RESULT;
+MINLINE bool compare_v4v4(const float v1[4],
+                          const float v2[4],
+                          float limit) ATTR_WARN_UNUSED_RESULT;
+
+MINLINE bool compare_v2v2_relative(const float v1[2], const float v2[2], float limit, int max_ulps)
     ATTR_WARN_UNUSED_RESULT;
-MINLINE bool compare_v3v3_relative(const float a[3], const float b[3], float limit, int max_ulps)
+MINLINE bool compare_v3v3_relative(const float v1[3], const float v2[3], float limit, int max_ulps)
     ATTR_WARN_UNUSED_RESULT;
-MINLINE bool compare_v4v4_relative(const float a[4], const float b[4], float limit, int max_ulps)
+MINLINE bool compare_v4v4_relative(const float v1[4], const float v2[4], float limit, int max_ulps)
     ATTR_WARN_UNUSED_RESULT;
 
-MINLINE bool compare_len_v3v3(const float a[3],
-                              const float b[3],
+MINLINE bool compare_len_v3v3(const float v1[3],
+                              const float v2[3],
                               float limit) ATTR_WARN_UNUSED_RESULT;
 
-MINLINE bool compare_size_v3v3(const float a[3],
-                               const float b[3],
+MINLINE bool compare_size_v3v3(const float v1[3],
+                               const float v2[3],
                                float limit) ATTR_WARN_UNUSED_RESULT;
 
 /**
@@ -606,8 +612,8 @@ void project_v3_plane(float out[3], const float plane_no[3], const float plane_c
  * out: result (negate for a 'bounce').
  * 
  */
-void reflect_v3_v3v3(float out[3], const float vec[3], const float normal[3]);
-void reflect_v3_v3v3_db(double out[3], const double vec[3], const double normal[3]);
+void reflect_v3_v3v3(float out[3], const float v[3], const float normal[3]);
+void reflect_v3_v3v3_db(double out[3], const double v[3], const double normal[3]);
 /**
  * Takes a vector and computes 2 orthogonal directions.
  *
@@ -655,10 +661,10 @@ void print_vn(const char *str, const float v[], int n);
 #define print_v4_id(v) print_v4(STRINGIFY(v), v)
 #define print_vn_id(v, n) print_vn(STRINGIFY(v), v, n)
 
-MINLINE void normal_float_to_short_v2(short r[2], const float n[2]);
-MINLINE void normal_short_to_float_v3(float r[3], const short n[3]);
-MINLINE void normal_float_to_short_v3(short r[3], const float n[3]);
-MINLINE void normal_float_to_short_v4(short r[4], const float n[4]);
+MINLINE void normal_float_to_short_v2(short out[2], const float in[2]);
+MINLINE void normal_short_to_float_v3(float out[3], const short in[3]);
+MINLINE void normal_float_to_short_v3(short out[3], const float in[3]);
+MINLINE void normal_float_to_short_v4(short out[4], const float in[4]);
 
 void minmax_v4v4_v4(float min[4], float max[4], const float vec[4]);
 void minmax_v3v3_v3(float min[3], float max[3], const float vec[3]);
diff --git a/source/blender/blenlib/BLI_memory_utils.hh b/source/blender/blenlib/BLI_memory_utils.hh
index 39b73deb276..7d504c18b4b 100644
--- a/source/blender/blenlib/BLI_memory_utils.hh
+++ b/source/blender/blenlib/BLI_memory_utils.hh
@@ -195,51 +195,51 @@ template void initialized_move_n(T *src, int64_t n, T *dst)
 }
 
 /**
- * Move n values from src to dst starting with the last value.
+ * Move n values from src to dst.
  *
  * Exception Safety: Basic.
  *
  * Before:
  *  src: initialized
- *  dst: initialized
+ *  dst: uninitialized
  * After:
  *  src: initialized, moved-from
  *  dst: initialized
  */
-template void initialized_reversed_move_n(T *src, int64_t n, T *dst)
+template void uninitialized_move_n(T *src, int64_t n, T *dst)
 {
   BLI_assert(n >= 0);
 
-  for (int64_t i = n - 1; i >= 0; i--) {
-    dst[i] = std::move(src[i]);
+  int64_t current = 0;
+  try {
+    for (; current < n; current++) {
+      new (static_cast(dst + current)) T(std::move(src[current]));
+    }
+  }
+  catch (...) {
+    destruct_n(dst, current);
+    throw;
   }
 }
 
 /**
- * Move n values from src to dst.
+ * Move n values from src to dst starting with the last value.
  *
  * Exception Safety: Basic.
  *
  * Before:
  *  src: initialized
- *  dst: uninitialized
+ *  dst: initialized
  * After:
  *  src: initialized, moved-from
  *  dst: initialized
  */
-template void uninitialized_move_n(T *src, int64_t n, T *dst)
+template void initialized_reversed_move_n(T *src, int64_t n, T *dst)
 {
   BLI_assert(n >= 0);
 
-  int64_t current = 0;
-  try {
-    for (; current < n; current++) {
-      new (static_cast(dst + current)) T(std::move(src[current]));
-    }
-  }
-  catch (...) {
-    destruct_n(dst, current);
-    throw;
+  for (int64_t i = n - 1; i >= 0; i--) {
+    dst[i] = std::move(src[i]);
   }
 }
 
@@ -354,8 +354,7 @@ template using destruct_ptr = std::unique_ptr class AlignedBuffer {
-  struct Empty {
-  };
+  struct Empty {};
   struct alignas(Alignment) Sized {
     /* Don't create an empty array. This causes problems with some compilers. */
     std::byte buffer_[Size > 0 ? Size : 1];
@@ -485,8 +484,7 @@ class alignas(ReservedAlignment) DynamicStackBuffer {
  * This can be used by container constructors. A parameter of this type should be used to indicate
  * that the constructor does not construct the elements.
  */
-class NoInitialization {
-};
+class NoInitialization {};
 
 /**
  * This can be used to mark a constructor of an object that does not throw exceptions. Other
@@ -494,8 +492,7 @@ class NoInitialization {
  * With this, the destructor of the object will be called, even when the remaining constructor
  * throws.
  */
-class NoExceptConstructor {
-};
+class NoExceptConstructor {};
 
 /**
  * Helper variable that checks if a pointer type can be converted into another pointer type without
diff --git a/source/blender/blenlib/BLI_multi_value_map.hh b/source/blender/blenlib/BLI_multi_value_map.hh
index 4b6300c09aa..81b536e7d3c 100644
--- a/source/blender/blenlib/BLI_multi_value_map.hh
+++ b/source/blender/blenlib/BLI_multi_value_map.hh
@@ -114,6 +114,14 @@ template class MultiValueMap {
     return {};
   }
 
+  /**
+   * Get the number of keys.
+   */
+  int64_t size() const
+  {
+    return map_.size();
+  }
+
   /**
    * NOTE: This signature will change when the implementation changes.
    */
@@ -137,6 +145,11 @@ template class MultiValueMap {
   {
     return map_.values();
   }
+
+  void clear()
+  {
+    map_.clear();
+  }
 };
 
 }  // namespace blender
diff --git a/source/blender/blenlib/BLI_path_util.h b/source/blender/blenlib/BLI_path_util.h
index 06dd9ab0db9..1e45e76afe1 100644
--- a/source/blender/blenlib/BLI_path_util.h
+++ b/source/blender/blenlib/BLI_path_util.h
@@ -35,16 +35,6 @@ void BLI_setenv_if_new(const char *env, const char *val) ATTR_NONNULL(1);
  */
 const char *BLI_getenv(const char *env) ATTR_NONNULL(1) ATTR_WARN_UNUSED_RESULT;
 
-/**
- * Returns in `string` the concatenation of `dir` and `file` (also with `relabase` on the
- * front if specified and `dir` begins with "//"). Normalizes all occurrences of path
- * separators, including ensuring there is exactly one between the copies of `dir` and `file`,
- * and between the copies of `relabase` and `dir`.
- *
- * \param relabase: Optional prefix to substitute for "//" on front of `dir`.
- * \param string: Area to return result.
- */
-void BLI_make_file_string(const char *relabase, char *string, const char *dir, const char *file);
 /**
  * Ensures that the parent directory of `name` exists.
  *
@@ -94,10 +84,18 @@ void BLI_join_dirfile(char *__restrict dst,
  * Join multiple strings into a path, ensuring only a single path separator between each,
  * and trailing slash is kept.
  *
+ * \param path: The first patch which has special treatment,
+ * allowing `//` prefix which is kept intact unlike double-slashes which are stripped
+ * from the bounds of all other paths passed in.
+ * Passing in the following paths all result in the same output (`//a/b/c`):
+ * - `"//", "a", "b", "c"`.
+ * - `"//", "/a/", "/b/", "/c"`.
+ * - `"//a", "b/c"`.
+ *
  * \note If you want a trailing slash, add `SEP_STR` as the last path argument,
  * duplicate slashes will be cleaned up.
  */
-size_t BLI_path_join(char *__restrict dst, size_t dst_len, const char *path_first, ...)
+size_t BLI_path_join(char *__restrict dst, size_t dst_len, const char *path, ...)
     ATTR_NONNULL(1, 3) ATTR_SENTINEL(0);
 /**
  * Like Python's `os.path.basename()`
@@ -108,10 +106,10 @@ size_t BLI_path_join(char *__restrict dst, size_t dst_len, const char *path_firs
 const char *BLI_path_basename(const char *path) ATTR_NONNULL() ATTR_WARN_UNUSED_RESULT;
 /**
  * Get an element of the path at an index, eg:
- * "/some/path/file.txt" where an index of:
- * - 0 or -3: "some"
- * - 1 or -2: "path"
- * - 2 or -1: "file.txt"
+ * `/some/path/file.txt` where an index of:
+ * - 0 or -3: `some`
+ * - 1 or -2: `path`
+ * - 2 or -1: `file.txt`
  *
  * Ignores multiple slashes at any point in the path (including start/end).
  */
@@ -367,8 +365,8 @@ void BLI_path_normalize_unc(char *path_16, int maxlen);
 /**
  * Appends a suffix to the string, fitting it before the extension
  *
- * string = Foo.png, suffix = 123, separator = _
- * Foo.png -> Foo_123.png
+ * string = `Foo.png`, suffix = `123`, separator = `_`.
+ * `Foo.png` -> `Foo_123.png`.
  *
  * \param string: original (and final) string
  * \param maxlen: Maximum length of string
diff --git a/source/blender/blenlib/BLI_pool.hh b/source/blender/blenlib/BLI_pool.hh
new file mode 100644
index 00000000000..8745c019db5
--- /dev/null
+++ b/source/blender/blenlib/BLI_pool.hh
@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/** \file
+ * \ingroup bli
+ *
+ * A `blender::Pool` allows fast allocation and deallocation of many elements of the same type.
+ *
+ * It is compatible with types that are not movable.
+ *
+ * Freed elements memory will be reused by next allocations.
+ * Elements are allocated in chunks to reduce memory fragmentation and avoid reallocation.
+ */
+
+#pragma once
+
+#include "BLI_stack.hh"
+#include "BLI_utility_mixins.hh"
+#include "BLI_vector.hh"
+
+namespace blender {
+
+template class Pool : NonCopyable {
+ private:
+  using Chunk = TypedBuffer;
+
+  /** Allocated item buffer. */
+  Vector> values_;
+  /** List of freed elements to be use for the next allocations. A Stack is best here to avoid
+   * overhead when growing the free list. It also offers better cache performance than a queue
+   * since last added entries will be reused first. */
+  Stack free_list_;
+
+ public:
+  ~Pool()
+  {
+    /* All elements need to be freed before freeing the pool. */
+    BLI_assert(this->size() == 0);
+  }
+
+  /**
+   * Construct an object inside this pool's memory.
+   */
+  template T &construct(ForwardT &&...value)
+  {
+    if (free_list_.is_empty()) {
+      values_.append(std::make_unique());
+      T *chunk_start = values_.last()->ptr();
+      for (auto i : IndexRange(ChunkLen)) {
+        free_list_.push(chunk_start + i);
+      }
+    }
+    T *ptr = free_list_.pop();
+    new (ptr) T(std::forward(value)...);
+    return *ptr;
+  }
+
+  /**
+   * Destroy the given element inside this memory pool. Memory will be reused by next element
+   * construction. This invokes undefined behavior if the item is not from this pool.
+   */
+  void destruct(T &value)
+  {
+    value.~T();
+    free_list_.push(&value);
+  }
+
+  /**
+   * Return the number of constructed elements in this pool.
+   */
+  int64_t size() const
+  {
+    return values_.size() * ChunkLen - free_list_.size();
+  }
+
+  /**
+   * Returns true when the pool contains no elements, otherwise false.
+   */
+  bool is_empty() const
+  {
+    return this->size() == 0;
+  }
+};
+
+}  // namespace blender
diff --git a/source/blender/blenlib/BLI_probing_strategies.hh b/source/blender/blenlib/BLI_probing_strategies.hh
index c6152e4d03d..2c001270495 100644
--- a/source/blender/blenlib/BLI_probing_strategies.hh
+++ b/source/blender/blenlib/BLI_probing_strategies.hh
@@ -2,6 +2,8 @@
 
 #pragma once
 
+#include 
+
 /** \file
  * \ingroup bli
  *
@@ -20,7 +22,7 @@
  * clustering issues. However, more linear steps can also make things slower when the initial hash
  * produces many collisions.
  *
- * Every probing strategy has to guarantee, that every possible uint64_t is returned eventually.
+ * Every probing strategy has to guarantee that every possible uint64_t is returned eventually.
  * This is necessary for correctness. If this is not the case, empty slots might not be found.
  *
  * The SLOT_PROBING_BEGIN and SLOT_PROBING_END macros can be used to implement a loop that iterates
@@ -69,7 +71,7 @@ class LinearProbingStrategy {
 
   int64_t linear_steps() const
   {
-    return UINT32_MAX;
+    return std::numeric_limits::max();
   }
 };
 
diff --git a/source/blender/blenlib/BLI_scanfill.h b/source/blender/blenlib/BLI_scanfill.h
index 04ac7cb05e4..b5b100ac27d 100644
--- a/source/blender/blenlib/BLI_scanfill.h
+++ b/source/blender/blenlib/BLI_scanfill.h
@@ -82,7 +82,7 @@ struct ScanFillEdge *BLI_scanfill_edge_add(ScanFillContext *sf_ctx,
                                            struct ScanFillVert *v2);
 
 enum {
-  /* NOTE(campbell): using BLI_SCANFILL_CALC_REMOVE_DOUBLES
+  /* NOTE(@campbellbarton): using #BLI_SCANFILL_CALC_REMOVE_DOUBLES
    * Assumes ordered edges, otherwise we risk an eternal loop
    * removing double verts. */
   BLI_SCANFILL_CALC_REMOVE_DOUBLES = (1 << 1),
diff --git a/source/blender/blenlib/BLI_serialize.hh b/source/blender/blenlib/BLI_serialize.hh
index bd91c522d06..e23d7d20d0b 100644
--- a/source/blender/blenlib/BLI_serialize.hh
+++ b/source/blender/blenlib/BLI_serialize.hh
@@ -55,7 +55,6 @@
  *
  * To add a new formatter a new sub-class of `Formatter` must be created and the
  * `serialize`/`deserialize` methods should be implemented.
- *
  */
 
 #include 
@@ -110,7 +109,6 @@ using ArrayValue = ContainerValue>, eValueType::Ar
  * - `DoubleValue`: contains a double precision floating point number.
  * - `DictionaryValue`: represents an object (key value pairs where keys are strings and values can
  *   be of different types.
- *
  */
 class Value {
  private:
diff --git a/source/blender/blenlib/BLI_set.hh b/source/blender/blenlib/BLI_set.hh
index 62de4b79e41..a1b6ad9754e 100644
--- a/source/blender/blenlib/BLI_set.hh
+++ b/source/blender/blenlib/BLI_set.hh
@@ -427,10 +427,10 @@ class Set {
       return *this;
     }
 
-    Iterator operator++(int) const
+    Iterator operator++(int)
     {
       Iterator copied_iterator = *this;
-      ++copied_iterator;
+      ++(*this);
       return copied_iterator;
     }
 
diff --git a/source/blender/blenlib/BLI_string_utf8.h b/source/blender/blenlib/BLI_string_utf8.h
index 4c5cc3fd9c5..61a21fd8bbf 100644
--- a/source/blender/blenlib/BLI_string_utf8.h
+++ b/source/blender/blenlib/BLI_string_utf8.h
@@ -157,8 +157,8 @@ size_t BLI_strnlen_utf8(const char *strc, size_t maxlen) ATTR_NONNULL(1) ATTR_WA
 size_t BLI_strncpy_wchar_as_utf8(char *__restrict dst,
                                  const wchar_t *__restrict src,
                                  size_t maxncpy) ATTR_NONNULL(1, 2);
-size_t BLI_strncpy_wchar_from_utf8(wchar_t *__restrict dst,
-                                   const char *__restrict src,
+size_t BLI_strncpy_wchar_from_utf8(wchar_t *__restrict dst_w,
+                                   const char *__restrict src_c,
                                    size_t maxncpy) ATTR_NONNULL(1, 2);
 
 /**
@@ -174,17 +174,17 @@ int BLI_str_utf8_char_width_safe(const char *p) ATTR_WARN_UNUSED_RESULT ATTR_NON
 
 size_t BLI_str_partition_utf8(const char *str,
                               const unsigned int delim[],
-                              const char **sep,
-                              const char **suf) ATTR_NONNULL(1, 2, 3, 4);
+                              const char **r_sep,
+                              const char **r_suf) ATTR_NONNULL(1, 2, 3, 4);
 size_t BLI_str_rpartition_utf8(const char *str,
                                const unsigned int delim[],
-                               const char **sep,
-                               const char **suf) ATTR_NONNULL(1, 2, 3, 4);
+                               const char **r_sep,
+                               const char **r_suf) ATTR_NONNULL(1, 2, 3, 4);
 size_t BLI_str_partition_ex_utf8(const char *str,
                                  const char *end,
                                  const unsigned int delim[],
-                                 const char **sep,
-                                 const char **suf,
+                                 const char **r_sep,
+                                 const char **r_suf,
                                  bool from_right) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL(1, 3, 4, 5);
 
 int BLI_str_utf8_offset_to_index(const char *str, int offset) ATTR_WARN_UNUSED_RESULT
diff --git a/source/blender/blenlib/BLI_task.hh b/source/blender/blenlib/BLI_task.hh
index 904dea66f7a..9f9a57be634 100644
--- a/source/blender/blenlib/BLI_task.hh
+++ b/source/blender/blenlib/BLI_task.hh
@@ -31,6 +31,7 @@
 #endif
 
 #include "BLI_index_range.hh"
+#include "BLI_lazy_threading.hh"
 #include "BLI_utildefines.h"
 
 namespace blender::threading {
@@ -56,6 +57,7 @@ void parallel_for(IndexRange range, int64_t grain_size, const Function &function
 #ifdef WITH_TBB
   /* Invoking tbb for small workloads has a large overhead. */
   if (range.size() >= grain_size) {
+    lazy_threading::send_hint();
     tbb::parallel_for(
         tbb::blocked_range(range.first(), range.one_after_last(), grain_size),
         [&](const tbb::blocked_range &subrange) {
@@ -78,6 +80,7 @@ Value parallel_reduce(IndexRange range,
 {
 #ifdef WITH_TBB
   if (range.size() >= grain_size) {
+    lazy_threading::send_hint();
     return tbb::parallel_reduce(
         tbb::blocked_range(range.first(), range.one_after_last(), grain_size),
         identity,
@@ -105,6 +108,23 @@ template void parallel_invoke(Functions &&...functions)
 #endif
 }
 
+/**
+ * Same #parallel_invoke, but allows disabling threading dynamically. This is useful because when
+ * the individual functions do very little work, there is a lot of overhead from starting parallel
+ * tasks.
+ */
+template
+void parallel_invoke(const bool use_threading, Functions &&...functions)
+{
+  if (use_threading) {
+    lazy_threading::send_hint();
+    parallel_invoke(std::forward(functions)...);
+  }
+  else {
+    (functions(), ...);
+  }
+}
+
 /** See #BLI_task_isolate for a description of what isolating a task means. */
 template void isolate_task(const Function &function)
 {
diff --git a/source/blender/blenlib/BLI_utildefines.h b/source/blender/blenlib/BLI_utildefines.h
index 7f9470a9111..9f68795a4a2 100644
--- a/source/blender/blenlib/BLI_utildefines.h
+++ b/source/blender/blenlib/BLI_utildefines.h
@@ -589,7 +589,7 @@ extern "C" {
 
 /** Performs `offsetof(typeof(data), member) + sizeof((data)->member)` for non-gcc compilers. */
 #define OFFSETOF_STRUCT_AFTER(_struct, _member) \
-  ((((const char *)&((_struct)->_member)) - ((const char *)(_struct))) + \
+  ((size_t)(((const char *)&((_struct)->_member)) - ((const char *)(_struct))) + \
    sizeof((_struct)->_member))
 
 /**
diff --git a/source/blender/blenlib/BLI_vector_adaptor.hh b/source/blender/blenlib/BLI_vector_adaptor.hh
deleted file mode 100644
index 82d731aacd8..00000000000
--- a/source/blender/blenlib/BLI_vector_adaptor.hh
+++ /dev/null
@@ -1,88 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-
-#pragma once
-
-/** \file
- * \ingroup bli
- *
- * A `blender::VectorAdaptor` is a container with a fixed maximum size and does not own the
- * underlying memory. When an adaptor is constructed, you have to provide it with an uninitialized
- * array that will be filled when elements are added to the vector. The vector adaptor is not able
- * to grow. Therefore, it is undefined behavior to add more elements than fit into the provided
- * buffer.
- */
-
-#include "BLI_span.hh"
-
-namespace blender {
-
-template class VectorAdaptor {
- private:
-  T *begin_;
-  T *end_;
-  T *capacity_end_;
-
- public:
-  VectorAdaptor() : begin_(nullptr), end_(nullptr), capacity_end_(nullptr)
-  {
-  }
-
-  VectorAdaptor(T *data, int64_t capacity, int64_t size = 0)
-      : begin_(data), end_(data + size), capacity_end_(data + capacity)
-  {
-  }
-
-  VectorAdaptor(MutableSpan span) : VectorAdaptor(span.data(), span.size(), 0)
-  {
-  }
-
-  void append(const T &value)
-  {
-    BLI_assert(end_ < capacity_end_);
-    new (end_) T(value);
-    end_++;
-  }
-
-  void append(T &&value)
-  {
-    BLI_assert(end_ < capacity_end_);
-    new (end_) T(std::move(value));
-    end_++;
-  }
-
-  void append_n_times(const T &value, int64_t n)
-  {
-    BLI_assert(end_ + n <= capacity_end_);
-    uninitialized_fill_n(end_, n, value);
-    end_ += n;
-  }
-
-  void extend(Span values)
-  {
-    BLI_assert(end_ + values.size() <= capacity_end_);
-    uninitialized_copy_n(values.data(), values.size(), end_);
-    end_ += values.size();
-  }
-
-  int64_t capacity() const
-  {
-    return capacity_end_ - begin_;
-  }
-
-  int64_t size() const
-  {
-    return end_ - begin_;
-  }
-
-  bool is_empty() const
-  {
-    return begin_ == end_;
-  }
-
-  bool is_full() const
-  {
-    return end_ == capacity_end_;
-  }
-};
-
-}  // namespace blender
diff --git a/source/blender/blenlib/BLI_vector_set.hh b/source/blender/blenlib/BLI_vector_set.hh
index b0a3696f245..1a42e776d3d 100644
--- a/source/blender/blenlib/BLI_vector_set.hh
+++ b/source/blender/blenlib/BLI_vector_set.hh
@@ -358,7 +358,7 @@ class VectorSet {
   }
 
   /**
-   * Return the location of the key in the vector. It is assumed, that the key is in the vector
+   * Return the location of the key in the vector. It is assumed that the key is in the vector
    * set. If this is not necessarily the case, use `index_of_try`.
    */
   int64_t index_of(const Key &key) const
diff --git a/source/blender/blenlib/BLI_virtual_array.hh b/source/blender/blenlib/BLI_virtual_array.hh
index 438fcc4b8f7..19ee2334bd9 100644
--- a/source/blender/blenlib/BLI_virtual_array.hh
+++ b/source/blender/blenlib/BLI_virtual_array.hh
@@ -23,6 +23,8 @@
  * see of the increased compile time and binary size is worth it.
  */
 
+#include 
+
 #include "BLI_any.hh"
 #include "BLI_array.hh"
 #include "BLI_index_mask.hh"
@@ -106,25 +108,7 @@ template class VArrayImpl {
    */
   virtual void materialize(IndexMask mask, MutableSpan r_span) const
   {
-    T *dst = r_span.data();
-    /* Optimize for a few different common cases. */
-    const CommonVArrayInfo info = this->common_info();
-    switch (info.type) {
-      case CommonVArrayInfo::Type::Any: {
-        mask.foreach_index([&](const int64_t i) { dst[i] = this->get(i); });
-        break;
-      }
-      case CommonVArrayInfo::Type::Span: {
-        const T *src = static_cast(info.data);
-        mask.foreach_index([&](const int64_t i) { dst[i] = src[i]; });
-        break;
-      }
-      case CommonVArrayInfo::Type::Single: {
-        const T single = *static_cast(info.data);
-        mask.foreach_index([&](const int64_t i) { dst[i] = single; });
-        break;
-      }
-    }
+    mask.foreach_index([&](const int64_t i) { r_span[i] = this->get(i); });
   }
 
   /**
@@ -133,24 +117,7 @@ template class VArrayImpl {
   virtual void materialize_to_uninitialized(IndexMask mask, MutableSpan r_span) const
   {
     T *dst = r_span.data();
-    /* Optimize for a few different common cases. */
-    const CommonVArrayInfo info = this->common_info();
-    switch (info.type) {
-      case CommonVArrayInfo::Type::Any: {
-        mask.foreach_index([&](const int64_t i) { new (dst + i) T(this->get(i)); });
-        break;
-      }
-      case CommonVArrayInfo::Type::Span: {
-        const T *src = static_cast(info.data);
-        mask.foreach_index([&](const int64_t i) { new (dst + i) T(src[i]); });
-        break;
-      }
-      case CommonVArrayInfo::Type::Single: {
-        const T single = *static_cast(info.data);
-        mask.foreach_index([&](const int64_t i) { new (dst + i) T(single); });
-        break;
-      }
-    }
+    mask.foreach_index([&](const int64_t i) { new (dst + i) T(this->get(i)); });
   }
 
   /**
@@ -286,8 +253,20 @@ template class VArrayImpl_For_Span : public VMutableArrayImpl {
     return data_ == static_cast(other_info.data);
   }
 
+  void materialize(IndexMask mask, MutableSpan r_span) const override
+  {
+    mask.foreach_index([&](const int64_t i) { r_span[i] = data_[i]; });
+  }
+
+  void materialize_to_uninitialized(IndexMask mask, MutableSpan r_span) const override
+  {
+    T *dst = r_span.data();
+    mask.foreach_index([&](const int64_t i) { new (dst + i) T(data_[i]); });
+  }
+
   void materialize_compressed(IndexMask mask, MutableSpan r_span) const override
   {
+    BLI_assert(mask.size() == r_span.size());
     mask.to_best_mask_type([&](auto best_mask) {
       for (const int64_t i : IndexRange(best_mask.size())) {
         r_span[i] = data_[best_mask[i]];
@@ -298,6 +277,7 @@ template class VArrayImpl_For_Span : public VMutableArrayImpl {
   void materialize_compressed_to_uninitialized(IndexMask mask,
                                                MutableSpan r_span) const override
   {
+    BLI_assert(mask.size() == r_span.size());
     T *dst = r_span.data();
     mask.to_best_mask_type([&](auto best_mask) {
       for (const int64_t i : IndexRange(best_mask.size())) {
@@ -315,6 +295,12 @@ template class VArrayImpl_For_Span_final final : public VArrayImpl_F
  public:
   using VArrayImpl_For_Span::VArrayImpl_For_Span;
 
+  VArrayImpl_For_Span_final(const Span data)
+      /* Cast const away, because the implementation for const and non const spans is shared. */
+      : VArrayImpl_For_Span({const_cast(data.data()), data.size()})
+  {
+  }
+
  private:
   CommonVArrayInfo common_info() const final
   {
@@ -370,6 +356,17 @@ template class VArrayImpl_For_Single final : public VArrayImpl {
     return CommonVArrayInfo(CommonVArrayInfo::Type::Single, true, &value_);
   }
 
+  void materialize(IndexMask mask, MutableSpan r_span) const override
+  {
+    r_span.fill_indices(mask, value_);
+  }
+
+  void materialize_to_uninitialized(IndexMask mask, MutableSpan r_span) const override
+  {
+    T *dst = r_span.data();
+    mask.foreach_index([&](const int64_t i) { new (dst + i) T(value_); });
+  }
+
   void materialize_compressed(IndexMask mask, MutableSpan r_span) const override
   {
     BLI_assert(mask.size() == r_span.size());
@@ -796,6 +793,18 @@ template class VArrayCommon {
     return *static_cast(info.data);
   }
 
+  /**
+   * Return the value that is returned for every index, if the array is stored as a single value.
+   */
+  std::optional get_if_single() const
+  {
+    const CommonVArrayInfo info = impl_->common_info();
+    if (info.type != CommonVArrayInfo::Type::Single) {
+      return std::nullopt;
+    }
+    return *static_cast(info.data);
+  }
+
   /**
    * Return true when the other virtual references the same underlying memory.
    */
@@ -898,10 +907,7 @@ template class VArray : public VArrayCommon {
 
   VArray(varray_tag::span /* tag */, Span span)
   {
-    /* Cast const away, because the virtual array implementation for const and non const spans is
-     * shared. */
-    MutableSpan mutable_span{const_cast(span.data()), span.size()};
-    this->template emplace>(mutable_span);
+    this->template emplace>(span);
   }
 
   VArray(varray_tag::single /* tag */, T value, const int64_t size)
diff --git a/source/blender/blenlib/CMakeLists.txt b/source/blender/blenlib/CMakeLists.txt
index 95b4987596e..e0d05f8c36a 100644
--- a/source/blender/blenlib/CMakeLists.txt
+++ b/source/blender/blenlib/CMakeLists.txt
@@ -1,8 +1,13 @@
 # SPDX-License-Identifier: GPL-2.0-or-later
 # Copyright 2006 Blender Foundation. All rights reserved.
 
+if(HAVE_EXECINFO_H)
+  add_definitions(-DHAVE_EXECINFO_H)
+endif()
+
 set(INC
   .
+  ..
   # ../blenkernel  # don't add this back!
   ../makesdna
   ../../../intern/atomic
@@ -19,7 +24,6 @@ set(INC_SYS
 )
 
 set(SRC
-  intern/BLI_args.c
   intern/BLI_array.c
   intern/BLI_assert.c
   intern/BLI_color.cc
@@ -44,11 +48,13 @@ set(SRC
   intern/array_store.c
   intern/array_store_utils.c
   intern/array_utils.c
+  intern/array_utils.cc
   intern/astar.c
   intern/bitmap.c
   intern/bitmap_draw_2d.c
   intern/boxpack_2d.c
   intern/buffer.c
+  intern/compute_context.cc
   intern/convexhull_2d.c
   intern/cpp_type.cc
   intern/delaunay_2d.cc
@@ -79,6 +85,7 @@ set(SRC
   intern/kdtree_3d.c
   intern/kdtree_4d.c
   intern/lasso_2d.c
+  intern/lazy_threading.cc
   intern/length_parameterize.cc
   intern/listbase.c
   intern/math_base.c
@@ -155,17 +162,18 @@ set(SRC
   BLI_alloca.h
   BLI_allocator.hh
   BLI_any.hh
-  BLI_args.h
   BLI_array.h
   BLI_array.hh
   BLI_array_store.h
   BLI_array_store_utils.h
   BLI_array_utils.h
+  BLI_array_utils.hh
   BLI_asan.h
   BLI_assert.h
   BLI_astar.h
   BLI_bitmap.h
   BLI_bitmap_draw_2d.h
+  BLI_bit_vector.hh
   BLI_blenlib.h
   BLI_bounds.hh
   BLI_boxpack_2d.h
@@ -175,6 +183,7 @@ set(SRC
   BLI_compiler_attrs.h
   BLI_compiler_compat.h
   BLI_compiler_typecheck.h
+  BLI_compute_context.hh
   BLI_console.h
   BLI_convexhull_2d.h
   BLI_cpp_type.hh
@@ -279,6 +288,7 @@ set(SRC
   BLI_path_util.h
   BLI_polyfill_2d.h
   BLI_polyfill_2d_beautify.h
+  BLI_pool.hh
   BLI_probing_strategies.hh
   BLI_quadric.h
   BLI_rand.h
@@ -323,7 +333,6 @@ set(SRC
   BLI_uuid.h
   BLI_uvproject.h
   BLI_vector.hh
-  BLI_vector_adaptor.hh
   BLI_vector_set.hh
   BLI_vector_set_slots.hh
   BLI_virtual_array.hh
@@ -347,6 +356,14 @@ set(LIB
   ${ZSTD_LIBRARIES}
 )
 
+if(NOT WITH_PYTHON_MODULE)
+  list(APPEND SRC
+    intern/BLI_args.c
+
+    BLI_args.h
+  )
+endif()
+
 if(WITH_MEM_VALGRIND)
   add_definitions(-DWITH_MEM_VALGRIND)
 endif()
@@ -424,6 +441,8 @@ if(WITH_GTESTS)
     tests/BLI_array_store_test.cc
     tests/BLI_array_test.cc
     tests/BLI_array_utils_test.cc
+    tests/BLI_bit_vector_test.cc
+    tests/BLI_bitmap_test.cc
     tests/BLI_bounds_test.cc
     tests/BLI_color_test.cc
     tests/BLI_cpp_type_test.cc
@@ -469,6 +488,7 @@ if(WITH_GTESTS)
     tests/BLI_multi_value_map_test.cc
     tests/BLI_path_util_test.cc
     tests/BLI_polyfill_2d_test.cc
+    tests/BLI_pool_test.cc
     tests/BLI_ressource_strings.h
     tests/BLI_serialize_test.cc
     tests/BLI_session_uuid_test.cc
diff --git a/source/blender/blenlib/intern/BLI_index_range.cc b/source/blender/blenlib/intern/BLI_index_range.cc
index 398228ab461..624dcc39fc5 100644
--- a/source/blender/blenlib/intern/BLI_index_range.cc
+++ b/source/blender/blenlib/intern/BLI_index_range.cc
@@ -44,4 +44,34 @@ Span IndexRange::as_span_internal() const
   return Span(s_current_array + start_, size_);
 }
 
+AlignedIndexRanges split_index_range_by_alignment(const IndexRange range, const int64_t alignment)
+{
+  BLI_assert(is_power_of_2_i(alignment));
+  const int64_t mask = alignment - 1;
+
+  AlignedIndexRanges aligned_ranges;
+
+  const int64_t start_chunk = range.start() & ~mask;
+  const int64_t end_chunk = range.one_after_last() & ~mask;
+  if (start_chunk == end_chunk) {
+    aligned_ranges.prefix = range;
+  }
+  else {
+    int64_t prefix_size = 0;
+    int64_t suffix_size = 0;
+    if (range.start() != start_chunk) {
+      prefix_size = alignment - (range.start() & mask);
+    }
+    if (range.one_after_last() != end_chunk) {
+      suffix_size = range.one_after_last() - end_chunk;
+    }
+    aligned_ranges.prefix = IndexRange(range.start(), prefix_size);
+    aligned_ranges.suffix = IndexRange(end_chunk, suffix_size);
+    aligned_ranges.aligned = IndexRange(aligned_ranges.prefix.one_after_last(),
+                                        range.size() - prefix_size - suffix_size);
+  }
+
+  return aligned_ranges;
+}
+
 }  // namespace blender
diff --git a/source/blender/blenlib/intern/BLI_kdopbvh.c b/source/blender/blenlib/intern/BLI_kdopbvh.c
index 62bf17bd415..a43b725b6e3 100644
--- a/source/blender/blenlib/intern/BLI_kdopbvh.c
+++ b/source/blender/blenlib/intern/BLI_kdopbvh.c
@@ -1385,7 +1385,7 @@ BVHTreeOverlap *BLI_bvhtree_overlap(
 
 static bool tree_intersect_plane_test(const float *bv, const float plane[4])
 {
-  /* TODO(germano): Support other KDOP geometries. */
+  /* TODO(@germano): Support other KDOP geometries. */
   const float bb_min[3] = {bv[0], bv[2], bv[4]};
   const float bb_max[3] = {bv[1], bv[3], bv[5]};
   float bb_near[3], bb_far[3];
diff --git a/source/blender/blenlib/intern/BLI_memarena.c b/source/blender/blenlib/intern/BLI_memarena.c
index 3b73a81012d..71a5dd0e044 100644
--- a/source/blender/blenlib/intern/BLI_memarena.c
+++ b/source/blender/blenlib/intern/BLI_memarena.c
@@ -53,7 +53,7 @@ static void memarena_buf_free_all(struct MemBuf *mb)
   while (mb != NULL) {
     struct MemBuf *mb_next = mb->next;
 
-    /* Unpoison memory because MEM_freeN might overwrite it. */
+    /* Unpoison memory because #MEM_freeN might overwrite it. */
     BLI_asan_unpoison(mb, (uint)MEM_allocN_len(mb));
 
     MEM_freeN(mb);
@@ -158,6 +158,7 @@ void *BLI_memarena_calloc(MemArena *ma, size_t size)
   BLI_assert(ma->use_calloc == false);
 
   ptr = BLI_memarena_alloc(ma, size);
+  BLI_assert(ptr != NULL);
   memset(ptr, 0, size);
 
   return ptr;
diff --git a/source/blender/blenlib/intern/BLI_memblock.c b/source/blender/blenlib/intern/BLI_memblock.c
index f780d520301..b03efd2b8a2 100644
--- a/source/blender/blenlib/intern/BLI_memblock.c
+++ b/source/blender/blenlib/intern/BLI_memblock.c
@@ -5,7 +5,6 @@
  * \ingroup bli
  *
  * Dead simple, fast memory allocator for allocating many elements of the same size.
- *
  */
 
 #include 
diff --git a/source/blender/blenlib/intern/array_utils.cc b/source/blender/blenlib/intern/array_utils.cc
new file mode 100644
index 00000000000..a837d6aceec
--- /dev/null
+++ b/source/blender/blenlib/intern/array_utils.cc
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "BLI_array_utils.hh"
+
+namespace blender::array_utils {
+
+void copy(const GVArray &src,
+          const IndexMask selection,
+          GMutableSpan dst,
+          const int64_t grain_size)
+{
+  BLI_assert(src.type() == dst.type());
+  BLI_assert(src.size() == dst.size());
+  threading::parallel_for(selection.index_range(), grain_size, [&](const IndexRange range) {
+    src.materialize_to_uninitialized(selection.slice(range), dst.data());
+  });
+}
+
+void gather(const GVArray &src,
+            const IndexMask indices,
+            GMutableSpan dst,
+            const int64_t grain_size)
+{
+  BLI_assert(src.type() == dst.type());
+  BLI_assert(indices.size() == dst.size());
+  threading::parallel_for(indices.index_range(), grain_size, [&](const IndexRange range) {
+    src.materialize_compressed_to_uninitialized(indices.slice(range), dst.slice(range).data());
+  });
+}
+
+}  // namespace blender::array_utils
diff --git a/source/blender/blenlib/intern/bitmap.c b/source/blender/blenlib/intern/bitmap.c
index 7fcbc31c066..2cc2fbc3e2f 100644
--- a/source/blender/blenlib/intern/bitmap.c
+++ b/source/blender/blenlib/intern/bitmap.c
@@ -11,6 +11,7 @@
 #include 
 
 #include "BLI_bitmap.h"
+#include "BLI_math_bits.h"
 #include "BLI_utildefines.h"
 
 void BLI_bitmap_set_all(BLI_bitmap *bitmap, bool set, size_t bits)
@@ -46,3 +47,22 @@ void BLI_bitmap_or_all(BLI_bitmap *dst, const BLI_bitmap *src, size_t bits)
     dst[i] |= src[i];
   }
 }
+
+int BLI_bitmap_find_first_unset(const BLI_bitmap *bitmap, const size_t bits)
+{
+  const size_t blocks_num = _BITMAP_NUM_BLOCKS(bits);
+  int result = -1;
+  /* Skip over completely set blocks. */
+  int index = 0;
+  while (index < blocks_num && bitmap[index] == ~0u) {
+    index++;
+  }
+  if (index < blocks_num) {
+    /* Found a partially used block: find the lowest unused bit. */
+    const uint m = ~bitmap[index];
+    BLI_assert(m != 0);
+    const uint bit_index = bitscan_forward_uint(m);
+    result = bit_index + (index << _BITMAP_POWER);
+  }
+  return result;
+}
diff --git a/source/blender/blenlib/intern/boxpack_2d.c b/source/blender/blenlib/intern/boxpack_2d.c
index 78f5088e8b1..d55a4a8c9ff 100644
--- a/source/blender/blenlib/intern/boxpack_2d.c
+++ b/source/blender/blenlib/intern/boxpack_2d.c
@@ -712,7 +712,6 @@ void BLI_box_pack_2d_fixedarea(ListBase *boxes, int width, int height, ListBase
          * #  Box  *  Small  #        #  Box  *         #
          * #       *         #        #       *         #
          * ###################        ###################
-         *
          */
         int area_hsplit_large = space->w * (space->h - box->h);
         int area_vsplit_large = (space->w - box->w) * space->h;
diff --git a/source/blender/blenlib/intern/compute_context.cc b/source/blender/blenlib/intern/compute_context.cc
new file mode 100644
index 00000000000..50a4a90a4a9
--- /dev/null
+++ b/source/blender/blenlib/intern/compute_context.cc
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "BLI_compute_context.hh"
+#include "BLI_hash_md5.h"
+
+namespace blender {
+
+void ComputeContextHash::mix_in(const void *data, int64_t len)
+{
+  DynamicStackBuffer<> buffer_owner(HashSizeInBytes + len, 8);
+  char *buffer = static_cast(buffer_owner.buffer());
+  memcpy(buffer, this, HashSizeInBytes);
+  memcpy(buffer + HashSizeInBytes, data, len);
+
+  BLI_hash_md5_buffer(buffer, HashSizeInBytes + len, this);
+}
+
+std::ostream &operator<<(std::ostream &stream, const ComputeContextHash &hash)
+{
+  std::stringstream ss;
+  ss << "0x" << std::hex << hash.v1 << hash.v2;
+  stream << ss.str();
+  return stream;
+}
+
+void ComputeContext::print_stack(std::ostream &stream, StringRef name) const
+{
+  Stack stack;
+  for (const ComputeContext *current = this; current; current = current->parent_) {
+    stack.push(current);
+  }
+  stream << "Context Stack: " << name << "\n";
+  while (!stack.is_empty()) {
+    const ComputeContext *current = stack.pop();
+    stream << "-> ";
+    current->print_current_in_line(stream);
+    const ComputeContextHash ¤t_hash = current->hash_;
+    stream << " \t(hash: " << current_hash << ")\n";
+  }
+}
+
+std::ostream &operator<<(std::ostream &stream, const ComputeContext &compute_context)
+{
+  compute_context.print_stack(stream, "");
+  return stream;
+}
+
+}  // namespace blender
diff --git a/source/blender/blenlib/intern/cpp_type.cc b/source/blender/blenlib/intern/cpp_type.cc
index d6a087cf175..38de32d3ec8 100644
--- a/source/blender/blenlib/intern/cpp_type.cc
+++ b/source/blender/blenlib/intern/cpp_type.cc
@@ -26,3 +26,4 @@ BLI_CPP_TYPE_MAKE(ColorGeometry4f, blender::ColorGeometry4f, CPPTypeFlags::Basic
 BLI_CPP_TYPE_MAKE(ColorGeometry4b, blender::ColorGeometry4b, CPPTypeFlags::BasicType)
 
 BLI_CPP_TYPE_MAKE(string, std::string, CPPTypeFlags::BasicType)
+BLI_CPP_TYPE_MAKE(StringVector, blender::Vector, CPPTypeFlags::None)
diff --git a/source/blender/blenlib/intern/filereader_zstd.c b/source/blender/blenlib/intern/filereader_zstd.c
index 5f114f24fb0..aeb000e9754 100644
--- a/source/blender/blenlib/intern/filereader_zstd.c
+++ b/source/blender/blenlib/intern/filereader_zstd.c
@@ -281,7 +281,10 @@ static void zstd_close(FileReader *reader)
   if (zstd->reader.seek) {
     MEM_freeN(zstd->seek.uncompressed_ofs);
     MEM_freeN(zstd->seek.compressed_ofs);
-    MEM_freeN(zstd->seek.cached_content);
+    /* When an error has occurred this may be NULL, see: T99744. */
+    if (zstd->seek.cached_content) {
+      MEM_freeN(zstd->seek.cached_content);
+    }
   }
   else {
     MEM_freeN((void *)zstd->in_buf.src);
diff --git a/source/blender/blenlib/intern/generic_virtual_array.cc b/source/blender/blenlib/intern/generic_virtual_array.cc
index 28bc66e8524..f66b1e14fc6 100644
--- a/source/blender/blenlib/intern/generic_virtual_array.cc
+++ b/source/blender/blenlib/intern/generic_virtual_array.cc
@@ -323,6 +323,7 @@ GVArraySpan::GVArraySpan(GVArraySpan &&other)
   else {
     data_ = owned_data_;
   }
+  other.owned_data_ = nullptr;
   other.data_ = nullptr;
   other.size_ = 0;
 }
@@ -393,6 +394,7 @@ GMutableVArraySpan::GMutableVArraySpan(GMutableVArraySpan &&other)
   else {
     data_ = owned_data_;
   }
+  other.owned_data_ = nullptr;
   other.data_ = nullptr;
   other.size_ = 0;
 }
@@ -402,7 +404,7 @@ GMutableVArraySpan::~GMutableVArraySpan()
   if (varray_) {
     if (show_not_saved_warning_) {
       if (!save_has_been_called_) {
-        std::cout << "Warning: Call `apply()` to make sure that changes persist in all cases.\n";
+        std::cout << "Warning: Call `save()` to make sure that changes persist in all cases.\n";
       }
     }
   }
diff --git a/source/blender/blenlib/intern/index_mask.cc b/source/blender/blenlib/intern/index_mask.cc
index f3590e4a41c..e9af183d60d 100644
--- a/source/blender/blenlib/intern/index_mask.cc
+++ b/source/blender/blenlib/intern/index_mask.cc
@@ -142,6 +142,7 @@ IndexMask find_indices_based_on_predicate__merge(
   int64_t result_mask_size = 0;
   for (Vector> &local_sub_masks : sub_masks) {
     for (Vector &sub_mask : local_sub_masks) {
+      BLI_assert(!sub_mask.is_empty());
       all_vectors.append(&sub_mask);
       result_mask_size += sub_mask.size();
     }
@@ -232,7 +233,9 @@ IndexMask find_indices_from_virtual_array(const IndexMask indices_to_check,
             }
           }
         });
-        sub_masks.local().append(std::move(masked_indices));
+        if (!masked_indices.is_empty()) {
+          sub_masks.local().append(std::move(masked_indices));
+        }
       });
 
   return detail::find_indices_based_on_predicate__merge(indices_to_check, sub_masks, r_indices);
diff --git a/source/blender/blenlib/intern/lazy_threading.cc b/source/blender/blenlib/intern/lazy_threading.cc
new file mode 100644
index 00000000000..803fd81a96d
--- /dev/null
+++ b/source/blender/blenlib/intern/lazy_threading.cc
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "BLI_lazy_threading.hh"
+#include "BLI_vector.hh"
+
+namespace blender::lazy_threading {
+
+/**
+ * This is a #RawVector so that it can be destructed after Blender checks for memory leaks.
+ */
+thread_local RawVector, 0> hint_receivers;
+
+void send_hint()
+{
+  for (const FunctionRef &fn : hint_receivers) {
+    fn();
+  }
+}
+
+HintReceiver::HintReceiver(const FunctionRef fn)
+{
+  hint_receivers.append(fn);
+}
+
+HintReceiver::~HintReceiver()
+{
+  hint_receivers.pop_last();
+}
+
+}  // namespace blender::lazy_threading
diff --git a/source/blender/blenlib/intern/math_geom.c b/source/blender/blenlib/intern/math_geom.c
index e7ccdeab80a..773aac95193 100644
--- a/source/blender/blenlib/intern/math_geom.c
+++ b/source/blender/blenlib/intern/math_geom.c
@@ -1667,8 +1667,8 @@ bool isect_ray_tri_v3(const float ray_origin[3],
                       float *r_lambda,
                       float r_uv[2])
 {
-  /* NOTE(campbell): these values were 0.000001 in 2.4x but for projection snapping on
-   * a human head (1BU == 1m), subsurf level 2, this gave many errors. */
+  /* NOTE(@campbellbarton): these values were 0.000001 in 2.4x but for projection snapping on
+   * a human head `(1BU == 1m)`, subdivision-surface level 2, this gave many errors. */
   const float epsilon = 0.00000001f;
   float p[3], s[3], e1[3], e2[3], q[3];
   float a, f, u, v;
@@ -3773,7 +3773,7 @@ void barycentric_weights_v2_quad(const float v1[2],
                                  const float co[2],
                                  float w[4])
 {
-  /* NOTE(campbell): fabsf() here is not needed for convex quads
+  /* NOTE(@campbellbarton): fabsf() here is not needed for convex quads
    * (and not used in #interp_weights_poly_v2).
    * But in the case of concave/bow-tie quads for the mask rasterizer it
    * gives unreliable results without adding `absf()`. If this becomes an issue for more general
diff --git a/source/blender/blenlib/intern/math_matrix.c b/source/blender/blenlib/intern/math_matrix.c
index ce9abc36cad..221ae84e74d 100644
--- a/source/blender/blenlib/intern/math_matrix.c
+++ b/source/blender/blenlib/intern/math_matrix.c
@@ -113,7 +113,6 @@ void copy_m4_m3(float m1[4][4], const float m2[3][3]) /* no clear */
   m1[2][1] = m2[2][1];
   m1[2][2] = m2[2][2];
 
-  /*  Reevan's Bugfix */
   m1[0][3] = 0.0f;
   m1[1][3] = 0.0f;
   m1[2][3] = 0.0f;
@@ -787,14 +786,14 @@ void mul_m2_v2(const float mat[2][2], float vec[2])
   mul_v2_m2v2(vec, mat, vec);
 }
 
-void mul_mat3_m4_v3(const float M[4][4], float r[3])
+void mul_mat3_m4_v3(const float mat[4][4], float r[3])
 {
   const float x = r[0];
   const float y = r[1];
 
-  r[0] = x * M[0][0] + y * M[1][0] + M[2][0] * r[2];
-  r[1] = x * M[0][1] + y * M[1][1] + M[2][1] * r[2];
-  r[2] = x * M[0][2] + y * M[1][2] + M[2][2] * r[2];
+  r[0] = x * mat[0][0] + y * mat[1][0] + mat[2][0] * r[2];
+  r[1] = x * mat[0][1] + y * mat[1][1] + mat[2][1] * r[2];
+  r[2] = x * mat[0][2] + y * mat[1][2] + mat[2][2] * r[2];
 }
 
 void mul_v3_mat3_m4v3(float r[3], const float mat[4][4], const float vec[3])
@@ -1116,16 +1115,32 @@ double determinant_m3_array_db(const double m[3][3])
           m[2][0] * (m[0][1] * m[1][2] - m[0][2] * m[1][1]));
 }
 
-bool invert_m3_ex(float m[3][3], const float epsilon)
+bool invert_m2_m2(float inverse[2][2], const float mat[2][2])
 {
-  float tmp[3][3];
-  const bool success = invert_m3_m3_ex(tmp, m, epsilon);
+  adjoint_m2_m2(inverse, mat);
+  float det = determinant_m2(mat[0][0], mat[1][0], mat[0][1], mat[1][1]);
 
-  copy_m3_m3(m, tmp);
+  bool success = (det != 0.0f);
+  if (success) {
+    inverse[0][0] /= det;
+    inverse[1][0] /= det;
+    inverse[0][1] /= det;
+    inverse[1][1] /= det;
+  }
+
+  return success;
+}
+
+bool invert_m3_ex(float mat[3][3], const float epsilon)
+{
+  float mat_tmp[3][3];
+  const bool success = invert_m3_m3_ex(mat_tmp, mat, epsilon);
+
+  copy_m3_m3(mat, mat_tmp);
   return success;
 }
 
-bool invert_m3_m3_ex(float m1[3][3], const float m2[3][3], const float epsilon)
+bool invert_m3_m3_ex(float inverse[3][3], const float mat[3][3], const float epsilon)
 {
   float det;
   int a, b;
@@ -1134,10 +1149,10 @@ bool invert_m3_m3_ex(float m1[3][3], const float m2[3][3], const float epsilon)
   BLI_assert(epsilon >= 0.0f);
 
   /* calc adjoint */
-  adjoint_m3_m3(m1, m2);
+  adjoint_m3_m3(inverse, mat);
 
   /* then determinant old matrix! */
-  det = determinant_m3_array(m2);
+  det = determinant_m3_array(mat);
 
   success = (fabsf(det) > epsilon);
 
@@ -1145,33 +1160,33 @@ bool invert_m3_m3_ex(float m1[3][3], const float m2[3][3], const float epsilon)
     det = 1.0f / det;
     for (a = 0; a < 3; a++) {
       for (b = 0; b < 3; b++) {
-        m1[a][b] *= det;
+        inverse[a][b] *= det;
       }
     }
   }
   return success;
 }
 
-bool invert_m3(float m[3][3])
+bool invert_m3(float mat[3][3])
 {
-  float tmp[3][3];
-  const bool success = invert_m3_m3(tmp, m);
+  float mat_tmp[3][3];
+  const bool success = invert_m3_m3(mat_tmp, mat);
 
-  copy_m3_m3(m, tmp);
+  copy_m3_m3(mat, mat_tmp);
   return success;
 }
 
-bool invert_m3_m3(float m1[3][3], const float m2[3][3])
+bool invert_m3_m3(float inverse[3][3], const float mat[3][3])
 {
   float det;
   int a, b;
   bool success;
 
   /* calc adjoint */
-  adjoint_m3_m3(m1, m2);
+  adjoint_m3_m3(inverse, mat);
 
   /* then determinant old matrix! */
-  det = determinant_m3_array(m2);
+  det = determinant_m3_array(mat);
 
   success = (det != 0.0f);
 
@@ -1179,7 +1194,7 @@ bool invert_m3_m3(float m1[3][3], const float m2[3][3])
     det = 1.0f / det;
     for (a = 0; a < 3; a++) {
       for (b = 0; b < 3; b++) {
-        m1[a][b] *= det;
+        inverse[a][b] *= det;
       }
     }
   }
@@ -1187,12 +1202,12 @@ bool invert_m3_m3(float m1[3][3], const float m2[3][3])
   return success;
 }
 
-bool invert_m4(float m[4][4])
+bool invert_m4(float mat[4][4])
 {
-  float tmp[4][4];
-  const bool success = invert_m4_m4(tmp, m);
+  float mat_tmp[4][4];
+  const bool success = invert_m4_m4(mat_tmp, mat);
 
-  copy_m4_m4(m, tmp);
+  copy_m4_m4(mat, mat_tmp);
   return success;
 }
 
@@ -2112,6 +2127,12 @@ void size_to_mat4(float R[4][4], const float size[3])
   R[3][3] = 1.0f;
 }
 
+void mat3_to_size_2d(float size[2], const float M[3][3])
+{
+  size[0] = len_v2(M[0]);
+  size[1] = len_v2(M[1]);
+}
+
 void mat3_to_size(float size[3], const float M[3][3])
 {
   size[0] = len_v3(M[0]);
@@ -2175,11 +2196,11 @@ float mat4_to_scale(const float mat[4][4])
   return len_v3(unit_vec);
 }
 
-float mat4_to_xy_scale(const float M[4][4])
+float mat4_to_xy_scale(const float mat[4][4])
 {
   /* unit length vector in xy plane */
   float unit_vec[3] = {(float)M_SQRT1_2, (float)M_SQRT1_2, 0.0f};
-  mul_mat3_m4_v3(M, unit_vec);
+  mul_mat3_m4_v3(mat, unit_vec);
   return len_v3(unit_vec);
 }
 
@@ -2224,12 +2245,6 @@ void mat4_to_loc_quat(float loc[3], float quat[4], const float wmat[4][4])
   copy_m3_m4(mat3, wmat);
   normalize_m3_m3(mat3_n, mat3);
 
-  /* So scale doesn't interfere with rotation T24291. */
-  /* FIXME: this is a workaround for negative matrix not working for rotation conversion. */
-  if (is_negative_m3(mat3)) {
-    negate_m3(mat3_n);
-  }
-
   mat3_normalized_to_quat(quat, mat3_n);
   copy_v3_v3(loc, wmat[3]);
 }
@@ -2238,7 +2253,7 @@ void mat4_decompose(float loc[3], float quat[4], float size[3], const float wmat
 {
   float rot[3][3];
   mat4_to_loc_rot_size(loc, rot, size, wmat);
-  mat3_normalized_to_quat(quat, rot);
+  mat3_normalized_to_quat_fast(quat, rot);
 }
 
 /**
@@ -2377,8 +2392,8 @@ void blend_m3_m3m3(float out[3][3],
   mat3_to_rot_size(drot, dscale, dst);
   mat3_to_rot_size(srot, sscale, src);
 
-  mat3_normalized_to_quat(dquat, drot);
-  mat3_normalized_to_quat(squat, srot);
+  mat3_normalized_to_quat_fast(dquat, drot);
+  mat3_normalized_to_quat_fast(squat, srot);
 
   /* do blending */
   interp_qt_qtqt(fquat, dquat, squat, srcweight);
@@ -2403,8 +2418,8 @@ void blend_m4_m4m4(float out[4][4],
   mat4_to_loc_rot_size(dloc, drot, dscale, dst);
   mat4_to_loc_rot_size(sloc, srot, sscale, src);
 
-  mat3_normalized_to_quat(dquat, drot);
-  mat3_normalized_to_quat(squat, srot);
+  mat3_normalized_to_quat_fast(dquat, drot);
+  mat3_normalized_to_quat_fast(squat, srot);
 
   /* do blending */
   interp_v3_v3v3(floc, dloc, sloc, srcweight);
@@ -2440,11 +2455,11 @@ void interp_m3_m3m3(float R[3][3], const float A[3][3], const float B[3][3], con
    * Note that a flip of two axes is just a rotation of 180 degrees around the third axis, and
    * three flipped axes are just an 180 degree rotation + a single axis flip. It is thus sufficient
    * to solve this problem for single axis flips. */
-  if (determinant_m3_array(U_A) < 0) {
+  if (is_negative_m3(U_A)) {
     mul_m3_fl(U_A, -1.0f);
     mul_m3_fl(P_A, -1.0f);
   }
-  if (determinant_m3_array(U_B) < 0) {
+  if (is_negative_m3(U_B)) {
     mul_m3_fl(U_B, -1.0f);
     mul_m3_fl(P_B, -1.0f);
   }
@@ -2485,16 +2500,14 @@ void interp_m4_m4m4(float R[4][4], const float A[4][4], const float B[4][4], con
 
 bool is_negative_m3(const float mat[3][3])
 {
-  float vec[3];
-  cross_v3_v3v3(vec, mat[0], mat[1]);
-  return (dot_v3v3(vec, mat[2]) < 0.0f);
+  return determinant_m3_array(mat) < 0.0f;
 }
 
 bool is_negative_m4(const float mat[4][4])
 {
-  float vec[3];
-  cross_v3_v3v3(vec, mat[0], mat[1]);
-  return (dot_v3v3(vec, mat[2]) < 0.0f);
+  /* Don't use #determinant_m4 as only the 3x3 components are needed
+   * when the matrix is used as a transformation to represent location/scale/rotation. */
+  return determinant_m4_mat3_array(mat) < 0.0f;
 }
 
 bool is_zero_m3(const float mat[3][3])
@@ -2552,11 +2565,8 @@ void loc_eul_size_to_mat4(float R[4][4],
   R[3][2] = loc[2];
 }
 
-void loc_eulO_size_to_mat4(float R[4][4],
-                           const float loc[3],
-                           const float eul[3],
-                           const float size[3],
-                           const short rotOrder)
+void loc_eulO_size_to_mat4(
+    float R[4][4], const float loc[3], const float eul[3], const float size[3], const short order)
 {
   float rmat[3][3], smat[3][3], tmat[3][3];
 
@@ -2564,7 +2574,7 @@ void loc_eulO_size_to_mat4(float R[4][4],
   unit_m4(R);
 
   /* Make rotation + scaling part. */
-  eulO_to_mat3(rmat, eul, rotOrder);
+  eulO_to_mat3(rmat, eul, order);
   size_to_mat3(smat, size);
   mul_m3_m3m3(tmat, rmat, smat);
 
@@ -3066,14 +3076,14 @@ void svd_m4(float U[4][4], float s[4], float V[4][4], float A_[4][4])
   }
 }
 
-void pseudoinverse_m4_m4(float Ainv[4][4], const float A_[4][4], float epsilon)
+void pseudoinverse_m4_m4(float inverse[4][4], const float mat[4][4], float epsilon)
 {
   /* compute Moore-Penrose pseudo inverse of matrix, singular values
    * below epsilon are ignored for stability (truncated SVD) */
   float A[4][4], V[4][4], W[4], Wm[4][4], U[4][4];
   int i;
 
-  transpose_m4_m4(A, A_);
+  transpose_m4_m4(A, mat);
   svd_m4(V, W, U, A);
   transpose_m4(U);
   transpose_m4(V);
@@ -3085,18 +3095,18 @@ void pseudoinverse_m4_m4(float Ainv[4][4], const float A_[4][4], float epsilon)
 
   transpose_m4(V);
 
-  mul_m4_series(Ainv, U, Wm, V);
+  mul_m4_series(inverse, U, Wm, V);
 }
 
-void pseudoinverse_m3_m3(float Ainv[3][3], const float A[3][3], float epsilon)
+void pseudoinverse_m3_m3(float inverse[3][3], const float mat[3][3], float epsilon)
 {
   /* try regular inverse when possible, otherwise fall back to slow svd */
-  if (!invert_m3_m3(Ainv, A)) {
-    float tmp[4][4], tmpinv[4][4];
+  if (!invert_m3_m3(inverse, mat)) {
+    float mat_tmp[4][4], tmpinv[4][4];
 
-    copy_m4_m3(tmp, A);
-    pseudoinverse_m4_m4(tmpinv, tmp, epsilon);
-    copy_m3_m4(Ainv, tmpinv);
+    copy_m4_m3(mat_tmp, mat);
+    pseudoinverse_m4_m4(tmpinv, mat_tmp, epsilon);
+    copy_m3_m4(inverse, tmpinv);
   }
 }
 
@@ -3106,22 +3116,22 @@ bool has_zero_axis_m4(const float matrix[4][4])
          len_squared_v3(matrix[2]) < FLT_EPSILON;
 }
 
-void invert_m4_m4_safe(float Ainv[4][4], const float A[4][4])
+void invert_m4_m4_safe(float inverse[4][4], const float mat[4][4])
 {
-  if (!invert_m4_m4(Ainv, A)) {
-    float Atemp[4][4];
+  if (!invert_m4_m4(inverse, mat)) {
+    float mat_tmp[4][4];
 
-    copy_m4_m4(Atemp, A);
+    copy_m4_m4(mat_tmp, mat);
 
     /* Matrix is degenerate (e.g. 0 scale on some axis), ideally we should
      * never be in this situation, but try to invert it anyway with tweak.
      */
-    Atemp[0][0] += 1e-8f;
-    Atemp[1][1] += 1e-8f;
-    Atemp[2][2] += 1e-8f;
+    mat_tmp[0][0] += 1e-8f;
+    mat_tmp[1][1] += 1e-8f;
+    mat_tmp[2][2] += 1e-8f;
 
-    if (!invert_m4_m4(Ainv, Atemp)) {
-      unit_m4(Ainv);
+    if (!invert_m4_m4(inverse, mat_tmp)) {
+      unit_m4(inverse);
     }
   }
 }
@@ -3141,24 +3151,24 @@ void invert_m4_m4_safe(float Ainv[4][4], const float A[4][4])
  * where we want to specify the length of the degenerate axes.
  * \{ */
 
-void invert_m4_m4_safe_ortho(float Ainv[4][4], const float A[4][4])
+void invert_m4_m4_safe_ortho(float inverse[4][4], const float mat[4][4])
 {
-  if (UNLIKELY(!invert_m4_m4(Ainv, A))) {
-    float Atemp[4][4];
-    copy_m4_m4(Atemp, A);
-    if (UNLIKELY(!(orthogonalize_m4_zero_axes(Atemp, 1.0f) && invert_m4_m4(Ainv, Atemp)))) {
-      unit_m4(Ainv);
+  if (UNLIKELY(!invert_m4_m4(inverse, mat))) {
+    float mat_tmp[4][4];
+    copy_m4_m4(mat_tmp, mat);
+    if (UNLIKELY(!(orthogonalize_m4_zero_axes(mat_tmp, 1.0f) && invert_m4_m4(inverse, mat_tmp)))) {
+      unit_m4(inverse);
     }
   }
 }
 
-void invert_m3_m3_safe_ortho(float Ainv[3][3], const float A[3][3])
+void invert_m3_m3_safe_ortho(float inverse[3][3], const float mat[3][3])
 {
-  if (UNLIKELY(!invert_m3_m3(Ainv, A))) {
-    float Atemp[3][3];
-    copy_m3_m3(Atemp, A);
-    if (UNLIKELY(!(orthogonalize_m3_zero_axes(Atemp, 1.0f) && invert_m3_m3(Ainv, Atemp)))) {
-      unit_m3(Ainv);
+  if (UNLIKELY(!invert_m3_m3(inverse, mat))) {
+    float mat_tmp[3][3];
+    copy_m3_m3(mat_tmp, mat);
+    if (UNLIKELY(!(orthogonalize_m3_zero_axes(mat_tmp, 1.0f) && invert_m3_m3(inverse, mat_tmp)))) {
+      unit_m3(inverse);
     }
   }
 }
diff --git a/source/blender/blenlib/intern/math_rotation.c b/source/blender/blenlib/intern/math_rotation.c
index 92223bdf1d5..ae068e3fb19 100644
--- a/source/blender/blenlib/intern/math_rotation.c
+++ b/source/blender/blenlib/intern/math_rotation.c
@@ -176,7 +176,7 @@ void quat_to_compatible_quat(float q[4], const float a[4], const float old[4])
   }
 }
 
-/* skip error check, currently only needed by mat3_to_quat_is_ok */
+/* Skip error check, currently only needed by #mat3_to_quat_legacy. */
 static void quat_to_mat3_no_error(float m[3][3], const float q[4])
 {
   double q0, q1, q2, q3, qda, qdb, qdc, qaa, qab, qac, qbb, qbc, qcc;
@@ -269,9 +269,11 @@ void quat_to_mat4(float m[4][4], const float q[4])
   m[3][3] = 1.0f;
 }
 
-void mat3_normalized_to_quat(float q[4], const float mat[3][3])
+void mat3_normalized_to_quat_fast(float q[4], const float mat[3][3])
 {
   BLI_ASSERT_UNIT_M3(mat);
+  /* Caller must ensure matrices aren't negative for valid results, see: T24291, T94231. */
+  BLI_assert(!is_negative_m3(mat));
 
   /* Check the trace of the matrix - bad precision if close to -1. */
   const float trace = mat[0][0] + mat[1][1] + mat[2][2];
@@ -332,34 +334,54 @@ void mat3_normalized_to_quat(float q[4], const float mat[3][3])
 
   normalize_qt(q);
 }
-void mat3_to_quat(float q[4], const float m[3][3])
-{
-  float unit_mat[3][3];
 
-  /* work on a copy */
-  /* this is needed AND a 'normalize_qt' in the end */
-  normalize_m3_m3(unit_mat, m);
-  mat3_normalized_to_quat(q, unit_mat);
+static void mat3_normalized_to_quat_with_checks(float q[4], float mat[3][3])
+{
+  const float det = determinant_m3_array(mat);
+  if (UNLIKELY(!isfinite(det))) {
+    unit_m3(mat);
+  }
+  else if (UNLIKELY(det < 0.0f)) {
+    negate_m3(mat);
+  }
+  mat3_normalized_to_quat_fast(q, mat);
 }
 
-void mat4_normalized_to_quat(float q[4], const float m[4][4])
+void mat3_normalized_to_quat(float q[4], const float mat[3][3])
 {
-  float mat3[3][3];
+  float unit_mat_abs[3][3];
+  copy_m3_m3(unit_mat_abs, mat);
+  mat3_normalized_to_quat_with_checks(q, unit_mat_abs);
+}
 
-  copy_m3_m4(mat3, m);
-  mat3_normalized_to_quat(q, mat3);
+void mat3_to_quat(float q[4], const float mat[3][3])
+{
+  float unit_mat_abs[3][3];
+  normalize_m3_m3(unit_mat_abs, mat);
+  mat3_normalized_to_quat_with_checks(q, unit_mat_abs);
 }
 
-void mat4_to_quat(float q[4], const float m[4][4])
+void mat4_normalized_to_quat(float q[4], const float mat[4][4])
 {
-  float mat3[3][3];
+  float unit_mat_abs[3][3];
+  copy_m3_m4(unit_mat_abs, mat);
+  mat3_normalized_to_quat_with_checks(q, unit_mat_abs);
+}
 
-  copy_m3_m4(mat3, m);
-  mat3_to_quat(q, mat3);
+void mat4_to_quat(float q[4], const float mat[4][4])
+{
+  float unit_mat_abs[3][3];
+  copy_m3_m4(unit_mat_abs, mat);
+  normalize_m3(unit_mat_abs);
+  mat3_normalized_to_quat_with_checks(q, unit_mat_abs);
 }
 
-void mat3_to_quat_is_ok(float q[4], const float wmat[3][3])
+void mat3_to_quat_legacy(float q[4], const float wmat[3][3])
 {
+  /* Legacy version of #mat3_to_quat which has slightly different behavior.
+   * Keep for particle-system & boids since replacing this will make subtle changes
+   * that impact hair in existing files. See: D15772. */
+
   float mat[3][3], matr[3][3], matn[3][3], q1[4], q2[4], angle, si, co, nor[3];
 
   /* work on a copy */
@@ -498,7 +520,10 @@ void rotation_between_quats_to_quat(float q[4], const float q1[4], const float q
   mul_qt_qtqt(q, tquat, q2);
 }
 
-float quat_split_swing_and_twist(const float q_in[4], int axis, float r_swing[4], float r_twist[4])
+float quat_split_swing_and_twist(const float q_in[4],
+                                 const int axis,
+                                 float r_swing[4],
+                                 float r_twist[4])
 {
   BLI_assert(axis >= 0 && axis <= 2);
 
@@ -915,6 +940,65 @@ float tri_to_quat(float q[4], const float a[3], const float b[3], const float c[
   return len;
 }
 
+void sin_cos_from_fraction(int numerator, int denominator, float *r_sin, float *r_cos)
+{
+  /* By default, creating a circle from an integer: calling #sinf & #cosf on the fraction doesn't
+   * create symmetrical values (because floats can't represent Pi exactly).
+   * Resolve this when the rotation is calculated from a fraction by mapping the `numerator`
+   * to lower values so X/Y values for points around a circle are exactly symmetrical, see T87779.
+   *
+   * Multiply both the `numerator` and `denominator` by eight to ensure we can divide the circle
+   * into 8 octants. For each octant, we then use symmetry and negation to bring the `numerator`
+   * closer to the origin where precision is highest.
+   *
+   * Cases 2, 4, 5 and 7, use the trigonometric identity sin(-x) == -sin(x).
+   * Cases 1, 2, 5 and 6, swap the pointers `r_sin` and `r_cos`.
+   */
+  BLI_assert(0 <= numerator);
+  BLI_assert(numerator <= denominator);
+  BLI_assert(denominator > 0);
+
+  numerator *= 8;                             /* Multiply numerator the same as denominator. */
+  const int octant = numerator / denominator; /* Determine the octant. */
+  denominator *= 8;                           /* Ensure denominator is a multiple of eight. */
+  float cos_sign = 1.0f;                      /* Either 1.0f or -1.0f. */
+
+  switch (octant) {
+    case 0:
+      /* Primary octant, nothing to do. */
+      break;
+    case 1:
+    case 2:
+      numerator = (denominator / 4) - numerator;
+      SWAP(float *, r_sin, r_cos);
+      break;
+    case 3:
+    case 4:
+      numerator = (denominator / 2) - numerator;
+      cos_sign = -1.0f;
+      break;
+    case 5:
+    case 6:
+      numerator = numerator - (denominator * 3 / 4);
+      SWAP(float *, r_sin, r_cos);
+      cos_sign = -1.0f;
+      break;
+    case 7:
+      numerator = numerator - denominator;
+      break;
+    default:
+      BLI_assert_unreachable();
+  }
+
+  BLI_assert(-denominator / 4 <= numerator); /* Numerator may be negative. */
+  BLI_assert(numerator <= denominator / 4);
+  BLI_assert(cos_sign == -1.0f || cos_sign == 1.0f);
+
+  const float angle = (float)(2.0 * M_PI) * ((float)numerator / (float)denominator);
+  *r_sin = sinf(angle);
+  *r_cos = cosf(angle) * cos_sign;
+}
+
 void print_qt(const char *str, const float q[4])
 {
   printf("%s: %.3f %.3f %.3f %.3f\n", str, q[0], q[1], q[2], q[3]);
@@ -1322,10 +1406,10 @@ void mat4_normalized_to_eul(float eul[3], const float m[4][4])
   copy_m3_m4(mat3, m);
   mat3_normalized_to_eul(eul, mat3);
 }
-void mat4_to_eul(float eul[3], const float m[4][4])
+void mat4_to_eul(float eul[3], const float mat[4][4])
 {
   float mat3[3][3];
-  copy_m3_m4(mat3, m);
+  copy_m3_m4(mat3, mat);
   mat3_to_eul(eul, mat3);
 }
 
@@ -1360,7 +1444,7 @@ void eul_to_quat(float quat[4], const float eul[3])
   quat[3] = cj * cs - sj * sc;
 }
 
-void rotate_eul(float beul[3], const char axis, const float ang)
+void rotate_eul(float beul[3], const char axis, const float angle)
 {
   float eul[3], mat1[3][3], mat2[3][3], totmat[3][3];
 
@@ -1368,13 +1452,13 @@ void rotate_eul(float beul[3], const char axis, const float ang)
 
   eul[0] = eul[1] = eul[2] = 0.0f;
   if (axis == 'X') {
-    eul[0] = ang;
+    eul[0] = angle;
   }
   else if (axis == 'Y') {
-    eul[1] = ang;
+    eul[1] = angle;
   }
   else {
-    eul[2] = ang;
+    eul[2] = angle;
   }
 
   eul_to_mat3(mat1, eul);
@@ -1730,23 +1814,23 @@ void mat3_to_compatible_eulO(float eul[3],
 void mat4_normalized_to_compatible_eulO(float eul[3],
                                         const float oldrot[3],
                                         const short order,
-                                        const float m[4][4])
+                                        const float mat[4][4])
 {
   float mat3[3][3];
 
   /* for now, we'll just do this the slow way (i.e. copying matrices) */
-  copy_m3_m4(mat3, m);
+  copy_m3_m4(mat3, mat);
   mat3_normalized_to_compatible_eulO(eul, oldrot, order, mat3);
 }
 void mat4_to_compatible_eulO(float eul[3],
                              const float oldrot[3],
                              const short order,
-                             const float m[4][4])
+                             const float mat[4][4])
 {
   float mat3[3][3];
 
   /* for now, we'll just do this the slow way (i.e. copying matrices) */
-  copy_m3_m4(mat3, m);
+  copy_m3_m4(mat3, mat);
   normalize_m3(mat3);
   mat3_normalized_to_compatible_eulO(eul, oldrot, order, mat3);
 }
@@ -1765,7 +1849,7 @@ void quat_to_compatible_eulO(float eul[3],
 /* rotate the given euler by the given angle on the specified axis */
 /* NOTE: is this safe to do with different axis orders? */
 
-void rotate_eulO(float beul[3], const short order, char axis, float ang)
+void rotate_eulO(float beul[3], const short order, const char axis, const float angle)
 {
   float eul[3], mat1[3][3], mat2[3][3], totmat[3][3];
 
@@ -1774,13 +1858,13 @@ void rotate_eulO(float beul[3], const short order, char axis, float ang)
   zero_v3(eul);
 
   if (axis == 'X') {
-    eul[0] = ang;
+    eul[0] = angle;
   }
   else if (axis == 'Y') {
-    eul[1] = ang;
+    eul[1] = angle;
   }
   else {
-    eul[2] = ang;
+    eul[2] = angle;
   }
 
   eulO_to_mat3(mat1, eul, order);
diff --git a/source/blender/blenlib/intern/math_rotation.cc b/source/blender/blenlib/intern/math_rotation.cc
index 74300d55954..091e8af85d9 100644
--- a/source/blender/blenlib/intern/math_rotation.cc
+++ b/source/blender/blenlib/intern/math_rotation.cc
@@ -23,4 +23,17 @@ float3 rotate_direction_around_axis(const float3 &direction, const float3 &axis,
   return axis_scaled + diff * std::cos(angle) + cross * std::sin(angle);
 }
 
+float3 rotate_around_axis(const float3 &vector,
+                          const float3 ¢er,
+                          const float3 &axis,
+                          const float angle)
+
+{
+  float3 result = vector - center;
+  float mat[3][3];
+  axis_angle_normalized_to_mat3(mat, axis, angle);
+  mul_m3_v3(mat, result);
+  return result + center;
+}
+
 }  // namespace blender::math
diff --git a/source/blender/blenlib/intern/mesh_boolean.cc b/source/blender/blenlib/intern/mesh_boolean.cc
index 700c126ca4c..0d8ad1da582 100644
--- a/source/blender/blenlib/intern/mesh_boolean.cc
+++ b/source/blender/blenlib/intern/mesh_boolean.cc
@@ -1675,7 +1675,7 @@ static Edge find_good_sorting_edge(const Vert *testp,
  * The algorithm is similar to the one for find_ambient_cell, except that
  * instead of an arbitrary point known to be outside the whole mesh, we
  * have a particular point (v) and we just want to determine the patches
- * that that point is between in sorting-around-an-edge order.
+ * that point is between in sorting-around-an-edge order.
  */
 static int find_containing_cell(const Vert *v,
                                 int t,
@@ -2966,6 +2966,11 @@ static std::ostream &operator<<(std::ostream &os, const FaceMergeState &fms)
  * \a tris all have the same original face.
  * Find the 2d edge/triangle topology for these triangles, but only the ones facing in the
  * norm direction, and whether each edge is dissolvable or not.
+ * If we did the initial triangulation properly, and any Delaunay triangulations of intersections
+ * properly, then each triangle edge should have at most one neighbor.
+ * However, there can be anomalies. For example, if an input face is self-intersecting, we fall
+ * back on the floating point poly-fill triangulation, which, after which all bets are off.
+ * Hence, try to be tolerant of such unexpected topology.
  */
 static void init_face_merge_state(FaceMergeState *fms,
                                   const Vector &tris,
@@ -3053,16 +3058,35 @@ static void init_face_merge_state(FaceMergeState *fms,
           std::cout << "me.v1 == mf.vert[i] so set edge[" << me_index << "].left_face = " << f
                     << "\n";
         }
-        BLI_assert(me.left_face == -1);
-        fms->edge[me_index].left_face = f;
+        if (me.left_face != -1) {
+          /* Unexpected in the normal case: this means more than one triangle shares this
+           * edge in the same orientation. But be tolerant of this case. By making this
+           * edge not dissolvable, we'll avoid future problems due to this non-manifold topology.
+           */
+          if (dbg_level > 1) {
+            std::cout << "me.left_face was already occupied, so triangulation wasn't good\n";
+          }
+          me.dissolvable = false;
+        }
+        else {
+          fms->edge[me_index].left_face = f;
+        }
       }
       else {
         if (dbg_level > 1) {
           std::cout << "me.v1 != mf.vert[i] so set edge[" << me_index << "].right_face = " << f
                     << "\n";
         }
-        BLI_assert(me.right_face == -1);
-        fms->edge[me_index].right_face = f;
+        if (me.right_face != -1) {
+          /* Unexpected, analogous to the me.left_face != -1 case above. */
+          if (dbg_level > 1) {
+            std::cout << "me.right_face was already occupied, so triangulation wasn't good\n";
+          }
+          me.dissolvable = false;
+        }
+        else {
+          fms->edge[me_index].right_face = f;
+        }
       }
       fms->face[f].edge.append(me_index);
     }
diff --git a/source/blender/blenlib/intern/mesh_intersect.cc b/source/blender/blenlib/intern/mesh_intersect.cc
index d5585f953ec..e8aa359fbe4 100644
--- a/source/blender/blenlib/intern/mesh_intersect.cc
+++ b/source/blender/blenlib/intern/mesh_intersect.cc
@@ -710,7 +710,7 @@ bool IMesh::erase_face_positions(int f_index, Span face_pos_erase, IMeshAr
      * mark with null pointer and caller should call remove_null_faces().
      * the loop is done.
      */
-    this->face_[f_index] = NULL;
+    this->face_[f_index] = nullptr;
     return true;
   }
   Array new_vert(new_len);
diff --git a/source/blender/blenlib/intern/noise.c b/source/blender/blenlib/intern/noise.c
index c39a2b5a27e..3ec7c3f9804 100644
--- a/source/blender/blenlib/intern/noise.c
+++ b/source/blender/blenlib/intern/noise.c
@@ -1125,7 +1125,7 @@ float BLI_noise_cell(float x, float y, float z)
   return (2.0f * BLI_cellNoiseU(x, y, z) - 1.0f);
 }
 
-void BLI_noise_cell_v3(float x, float y, float z, float ca[3])
+void BLI_noise_cell_v3(float x, float y, float z, float r_ca[3])
 {
   /* avoid precision issues on unit coordinates */
   x = (x + 0.000001f) * 1.00001f;
@@ -1136,9 +1136,9 @@ void BLI_noise_cell_v3(float x, float y, float z, float ca[3])
   int yi = (int)(floor(y));
   int zi = (int)(floor(z));
   const float *p = HASHPNT(xi, yi, zi);
-  ca[0] = p[0];
-  ca[1] = p[1];
-  ca[2] = p[2];
+  r_ca[0] = p[0];
+  r_ca[1] = p[1];
+  r_ca[2] = p[2];
 }
 
 /** \} */
diff --git a/source/blender/blenlib/intern/noise.cc b/source/blender/blenlib/intern/noise.cc
index a514c9e5183..8a073239b31 100644
--- a/source/blender/blenlib/intern/noise.cc
+++ b/source/blender/blenlib/intern/noise.cc
@@ -263,7 +263,6 @@ BLI_INLINE float mix(float v0, float v1, float x)
  *  +         +       |
  *  @ + + + + @       @------> x
  * v0          v1
- *
  */
 BLI_INLINE float mix(float v0, float v1, float v2, float v3, float x, float y)
 {
@@ -809,15 +808,14 @@ float musgrave_hybrid_multi_fractal(const float co,
 {
   float p = co;
   const float pwHL = std::pow(lacunarity, -H);
-  float pwr = pwHL;
 
-  float value = perlin_signed(p) + offset;
-  float weight = gain * value;
-  p *= lacunarity;
+  float pwr = 1.0f;
+  float value = 0.0f;
+  float weight = 1.0f;
 
   const float octaves = CLAMPIS(octaves_unclamped, 0.0f, 15.0f);
 
-  for (int i = 1; (weight > 0.001f) && (i < (int)octaves); i++) {
+  for (int i = 0; (weight > 0.001f) && (i < (int)octaves); i++) {
     if (weight > 1.0f) {
       weight = 1.0f;
     }
@@ -830,8 +828,12 @@ float musgrave_hybrid_multi_fractal(const float co,
   }
 
   const float rmd = octaves - floorf(octaves);
-  if (rmd != 0.0f) {
-    value += rmd * ((perlin_signed(p) + offset) * pwr);
+  if ((rmd != 0.0f) && (weight > 0.001f)) {
+    if (weight > 1.0f) {
+      weight = 1.0f;
+    }
+    float signal = (perlin_signed(p) + offset) * pwr;
+    value += rmd * weight * signal;
   }
 
   return value;
@@ -961,15 +963,14 @@ float musgrave_hybrid_multi_fractal(const float2 co,
 {
   float2 p = co;
   const float pwHL = std::pow(lacunarity, -H);
-  float pwr = pwHL;
 
-  float value = perlin_signed(p) + offset;
-  float weight = gain * value;
-  p *= lacunarity;
+  float pwr = 1.0f;
+  float value = 0.0f;
+  float weight = 1.0f;
 
   const float octaves = CLAMPIS(octaves_unclamped, 0.0f, 15.0f);
 
-  for (int i = 1; (weight > 0.001f) && (i < (int)octaves); i++) {
+  for (int i = 0; (weight > 0.001f) && (i < (int)octaves); i++) {
     if (weight > 1.0f) {
       weight = 1.0f;
     }
@@ -982,8 +983,12 @@ float musgrave_hybrid_multi_fractal(const float2 co,
   }
 
   const float rmd = octaves - floorf(octaves);
-  if (rmd != 0.0f) {
-    value += rmd * ((perlin_signed(p) + offset) * pwr);
+  if ((rmd != 0.0f) && (weight > 0.001f)) {
+    if (weight > 1.0f) {
+      weight = 1.0f;
+    }
+    float signal = (perlin_signed(p) + offset) * pwr;
+    value += rmd * weight * signal;
   }
 
   return value;
@@ -1115,15 +1120,14 @@ float musgrave_hybrid_multi_fractal(const float3 co,
 {
   float3 p = co;
   const float pwHL = std::pow(lacunarity, -H);
-  float pwr = pwHL;
 
-  float value = perlin_signed(p) + offset;
-  float weight = gain * value;
-  p *= lacunarity;
+  float pwr = 1.0f;
+  float value = 0.0f;
+  float weight = 1.0f;
 
   const float octaves = CLAMPIS(octaves_unclamped, 0.0f, 15.0f);
 
-  for (int i = 1; (weight > 0.001f) && (i < (int)octaves); i++) {
+  for (int i = 0; (weight > 0.001f) && (i < (int)octaves); i++) {
     if (weight > 1.0f) {
       weight = 1.0f;
     }
@@ -1136,8 +1140,12 @@ float musgrave_hybrid_multi_fractal(const float3 co,
   }
 
   const float rmd = octaves - floorf(octaves);
-  if (rmd != 0.0f) {
-    value += rmd * ((perlin_signed(p) + offset) * pwr);
+  if ((rmd != 0.0f) && (weight > 0.001f)) {
+    if (weight > 1.0f) {
+      weight = 1.0f;
+    }
+    float signal = (perlin_signed(p) + offset) * pwr;
+    value += rmd * weight * signal;
   }
 
   return value;
@@ -1269,15 +1277,14 @@ float musgrave_hybrid_multi_fractal(const float4 co,
 {
   float4 p = co;
   const float pwHL = std::pow(lacunarity, -H);
-  float pwr = pwHL;
 
-  float value = perlin_signed(p) + offset;
-  float weight = gain * value;
-  p *= lacunarity;
+  float pwr = 1.0f;
+  float value = 0.0f;
+  float weight = 1.0f;
 
   const float octaves = CLAMPIS(octaves_unclamped, 0.0f, 15.0f);
 
-  for (int i = 1; (weight > 0.001f) && (i < (int)octaves); i++) {
+  for (int i = 0; (weight > 0.001f) && (i < (int)octaves); i++) {
     if (weight > 1.0f) {
       weight = 1.0f;
     }
@@ -1290,8 +1297,12 @@ float musgrave_hybrid_multi_fractal(const float4 co,
   }
 
   const float rmd = octaves - floorf(octaves);
-  if (rmd != 0.0f) {
-    value += rmd * ((perlin_signed(p) + offset) * pwr);
+  if ((rmd != 0.0f) && (weight > 0.001f)) {
+    if (weight > 1.0f) {
+      weight = 1.0f;
+    }
+    float signal = (perlin_signed(p) + offset) * pwr;
+    value += rmd * weight * signal;
   }
 
   return value;
diff --git a/source/blender/blenlib/intern/path_util.c b/source/blender/blenlib/intern/path_util.c
index 5a96221c8d1..9b91636b055 100644
--- a/source/blender/blenlib/intern/path_util.c
+++ b/source/blender/blenlib/intern/path_util.c
@@ -466,8 +466,8 @@ void BLI_path_rel(char *file, const char *relfile)
 #ifdef WIN32
   if (BLI_strnlen(relfile, 3) > 2 && !BLI_path_is_abs(relfile)) {
     char *ptemp;
-    /* fix missing volume name in relative base,
-     * can happen with old recent-files.txt files */
+    /* Fix missing volume name in relative base,
+     * can happen with old `recent-files.txt` files. */
     BLI_windows_get_default_root_dir(temp);
     ptemp = &temp[2];
     if (!ELEM(relfile[0], '\\', '/')) {
@@ -1105,29 +1105,29 @@ bool BLI_path_program_search(char *fullname, const size_t maxlen, const char *na
 
   path = BLI_getenv("PATH");
   if (path) {
-    char filename[FILE_MAX];
+    char filepath_test[FILE_MAX];
     const char *temp;
 
     do {
       temp = strchr(path, separator);
       if (temp) {
-        memcpy(filename, path, temp - path);
-        filename[temp - path] = 0;
+        memcpy(filepath_test, path, temp - path);
+        filepath_test[temp - path] = 0;
         path = temp + 1;
       }
       else {
-        BLI_strncpy(filename, path, sizeof(filename));
+        BLI_strncpy(filepath_test, path, sizeof(filepath_test));
       }
 
-      BLI_path_append(filename, maxlen, name);
+      BLI_path_append(filepath_test, maxlen, name);
       if (
 #ifdef _WIN32
-          BLI_path_program_extensions_add_win32(filename, maxlen)
+          BLI_path_program_extensions_add_win32(filepath_test, maxlen)
 #else
-          BLI_exists(filename)
+          BLI_exists(filepath_test)
 #endif
       ) {
-        BLI_strncpy(fullname, filename, maxlen);
+        BLI_strncpy(fullname, filepath_test, maxlen);
         retval = true;
         break;
       }
@@ -1204,87 +1204,6 @@ bool BLI_make_existing_file(const char *name)
   return BLI_dir_create_recursive(di);
 }
 
-void BLI_make_file_string(const char *relabase, char *string, const char *dir, const char *file)
-{
-  int sl;
-
-  if (string) {
-    /* ensure this is always set even if dir/file are NULL */
-    string[0] = '\0';
-
-    if (ELEM(NULL, dir, file)) {
-      return; /* We don't want any NULLs */
-    }
-  }
-  else {
-    return; /* string is NULL, probably shouldn't happen but return anyway */
-  }
-
-  /* Resolve relative references */
-  if (relabase && dir[0] == '/' && dir[1] == '/') {
-    char *lslash;
-
-    /* Get the file name, chop everything past the last slash (ie. the filename) */
-    strcpy(string, relabase);
-
-    lslash = (char *)BLI_path_slash_rfind(string);
-    if (lslash) {
-      *(lslash + 1) = 0;
-    }
-
-    dir += 2; /* Skip over the relative reference */
-  }
-#ifdef WIN32
-  else {
-    if (BLI_strnlen(dir, 3) >= 2 && dir[1] == ':') {
-      BLI_strncpy(string, dir, 3);
-      dir += 2;
-    }
-    else if (BLI_strnlen(dir, 3) >= 2 && BLI_path_is_unc(dir)) {
-      string[0] = 0;
-    }
-    else { /* no drive specified */
-           /* first option: get the drive from the relabase if it has one */
-      if (relabase && BLI_strnlen(relabase, 3) >= 2 && relabase[1] == ':') {
-        BLI_strncpy(string, relabase, 3);
-        string[2] = '\\';
-        string[3] = '\0';
-      }
-      else { /* we're out of luck here, guessing the first valid drive, usually c:\ */
-        BLI_windows_get_default_root_dir(string);
-      }
-
-      /* ignore leading slashes */
-      while (ELEM(*dir, '/', '\\')) {
-        dir++;
-      }
-    }
-  }
-#endif
-
-  strcat(string, dir);
-
-  /* Make sure string ends in one (and only one) slash */
-  /* first trim all slashes from the end of the string */
-  sl = strlen(string);
-  while ((sl > 0) && ELEM(string[sl - 1], '/', '\\')) {
-    string[sl - 1] = '\0';
-    sl--;
-  }
-  /* since we've now removed all slashes, put back one slash at the end. */
-  strcat(string, "/");
-
-  while (ELEM(*file, '/', '\\')) {
-    /* Trim slashes from the front of file */
-    file++;
-  }
-
-  strcat(string, file);
-
-  /* Push all slashes to the system preferred direction */
-  BLI_path_slash_native(string);
-}
-
 static bool path_extension_check_ex(const char *str,
                                     const size_t str_len,
                                     const char *ext,
@@ -1586,8 +1505,8 @@ size_t BLI_path_join(char *__restrict dst, const size_t dst_len, const char *pat
     return ofs;
   }
 
-  /* remove trailing slashes, unless there are _only_ trailing slashes
-   * (allow "//" as the first argument). */
+  /* Remove trailing slashes, unless there are *only* trailing slashes
+   * (allow `//` or `//some_path` as the first argument). */
   bool has_trailing_slash = false;
   if (ofs != 0) {
     size_t len = ofs;
diff --git a/source/blender/blenlib/intern/rct.c b/source/blender/blenlib/intern/rct.c
index 0bb606c288e..7248db5b718 100644
--- a/source/blender/blenlib/intern/rct.c
+++ b/source/blender/blenlib/intern/rct.c
@@ -265,7 +265,7 @@ bool BLI_rcti_isect_segment(const rcti *rect, const int s1[2], const int s2[2])
   /* diagonal: [/] */
   tvec1[0] = rect->xmin;
   tvec1[1] = rect->ymin;
-  tvec2[0] = rect->xmin;
+  tvec2[0] = rect->xmax;
   tvec2[1] = rect->ymax;
   if (isect_segments_i(s1, s2, tvec1, tvec2)) {
     return true;
@@ -311,7 +311,7 @@ bool BLI_rctf_isect_segment(const rctf *rect, const float s1[2], const float s2[
   /* diagonal: [/] */
   tvec1[0] = rect->xmin;
   tvec1[1] = rect->ymin;
-  tvec2[0] = rect->xmin;
+  tvec2[0] = rect->xmax;
   tvec2[1] = rect->ymax;
   if (isect_segments_fl(s1, s2, tvec1, tvec2)) {
     return true;
diff --git a/source/blender/blenlib/intern/scanfill.c b/source/blender/blenlib/intern/scanfill.c
index 92fd7f5937b..33d387a5447 100644
--- a/source/blender/blenlib/intern/scanfill.c
+++ b/source/blender/blenlib/intern/scanfill.c
@@ -44,7 +44,7 @@ typedef struct ScanFillVertLink {
   ScanFillEdge *edge_first, *edge_last;
 } ScanFillVertLink;
 
-/* local funcs */
+/* Local functions. */
 
 #define SF_EPSILON 0.00003f
 #define SF_EPSILON_SQ (SF_EPSILON * SF_EPSILON)
diff --git a/source/blender/blenlib/intern/smallhash.c b/source/blender/blenlib/intern/smallhash.c
index 2d76f662611..8263f8ff34e 100644
--- a/source/blender/blenlib/intern/smallhash.c
+++ b/source/blender/blenlib/intern/smallhash.c
@@ -329,8 +329,7 @@ void **BLI_smallhash_iternew_p(const SmallHash *sh, SmallHashIter *iter, uintptr
 /** \name Debugging & Introspection
  * \{ */
 
-/* NOTE(campbell): this was called _print_smhash in knifetool.c
- * it may not be intended for general use. */
+/* NOTE(@campbellbarton): useful for debugging but may not be intended for general use. */
 #if 0
 void BLI_smallhash_print(SmallHash *sh)
 {
diff --git a/source/blender/blenlib/intern/storage.c b/source/blender/blenlib/intern/storage.c
index 4fa5ca0c088..c04fc41ab4d 100644
--- a/source/blender/blenlib/intern/storage.c
+++ b/source/blender/blenlib/intern/storage.c
@@ -259,7 +259,7 @@ eFileAttributes BLI_file_attributes(const char *path)
 #ifndef __APPLE__
 bool BLI_file_alias_target(const char *filepath,
                            /* This parameter can only be `const` on Linux since
-                            * redirections are not supported there.
+                            * redirection is not supported there.
                             * NOLINTNEXTLINE: readability-non-const-parameter. */
                            char r_targetpath[/*FILE_MAXDIR*/])
 {
diff --git a/source/blender/blenlib/intern/string_cursor_utf8.c b/source/blender/blenlib/intern/string_cursor_utf8.c
index 7a23b4bb4ad..6b7151be969 100644
--- a/source/blender/blenlib/intern/string_cursor_utf8.c
+++ b/source/blender/blenlib/intern/string_cursor_utf8.c
@@ -206,7 +206,7 @@ void BLI_str_cursor_step_utf8(const char *str,
  * less complex since it doesn't need to do multi-byte stepping.
  */
 
-/* helper funcs so we can match BLI_str_cursor_step_utf8 */
+/* Helper functions so we can match #BLI_str_cursor_step_utf8. */
 static bool cursor_step_next_utf32(const char32_t *UNUSED(str), size_t maxlen, int *pos)
 {
   if ((*pos) >= (int)maxlen) {
diff --git a/source/blender/blenlib/intern/string_search.cc b/source/blender/blenlib/intern/string_search.cc
index 14d85b99739..31ea24eb494 100644
--- a/source/blender/blenlib/intern/string_search.cc
+++ b/source/blender/blenlib/intern/string_search.cc
@@ -11,8 +11,8 @@
 #include "BLI_timeit.hh"
 
 /* Right arrow, keep in sync with #UI_MENU_ARROW_SEP in `UI_interface.h`. */
-#define UI_MENU_ARROW_SEP "\xe2\x96\xb6"
-#define UI_MENU_ARROW_SEP_UNICODE 0x25b6
+#define UI_MENU_ARROW_SEP "\xe2\x96\xb8"
+#define UI_MENU_ARROW_SEP_UNICODE 0x25b8
 
 namespace blender::string_search {
 
diff --git a/source/blender/blenlib/intern/string_utf8.c b/source/blender/blenlib/intern/string_utf8.c
index 0cbf62cce03..17fb451e422 100644
--- a/source/blender/blenlib/intern/string_utf8.c
+++ b/source/blender/blenlib/intern/string_utf8.c
@@ -403,7 +403,7 @@ int BLI_str_utf8_char_width_safe(const char *p)
 
 /* copied from glib's gutf8.c, added 'Err' arg */
 
-/* NOTE(campbell): glib uses uint for unicode, best we do the same,
+/* NOTE(@campbellbarton): glib uses uint for unicode, best we do the same,
  * though we don't typedef it. */
 
 #define UTF8_COMPUTE(Char, Mask, Len, Err) \
@@ -692,25 +692,25 @@ const char *BLI_str_find_next_char_utf8(const char *p, const char *str_end)
 
 size_t BLI_str_partition_utf8(const char *str,
                               const uint delim[],
-                              const char **sep,
-                              const char **suf)
+                              const char **r_sep,
+                              const char **r_suf)
 {
-  return BLI_str_partition_ex_utf8(str, NULL, delim, sep, suf, false);
+  return BLI_str_partition_ex_utf8(str, NULL, delim, r_sep, r_suf, false);
 }
 
 size_t BLI_str_rpartition_utf8(const char *str,
                                const uint delim[],
-                               const char **sep,
-                               const char **suf)
+                               const char **r_sep,
+                               const char **r_suf)
 {
-  return BLI_str_partition_ex_utf8(str, NULL, delim, sep, suf, true);
+  return BLI_str_partition_ex_utf8(str, NULL, delim, r_sep, r_suf, true);
 }
 
 size_t BLI_str_partition_ex_utf8(const char *str,
                                  const char *end,
                                  const uint delim[],
-                                 const char **sep,
-                                 const char **suf,
+                                 const char **r_sep,
+                                 const char **r_suf,
                                  const bool from_right)
 {
   const size_t str_len = end ? (size_t)(end - str) : strlen(str);
@@ -721,36 +721,32 @@ size_t BLI_str_partition_ex_utf8(const char *str,
   /* Note that here, we assume end points to a valid utf8 char! */
   BLI_assert((end >= str) && (BLI_str_utf8_as_unicode(end) != BLI_UTF8_ERR));
 
-  *suf = (char *)(str + str_len);
-
-  size_t index;
-  for (*sep = (char *)(from_right ? BLI_str_find_prev_char_utf8(end, str) : str), index = 0;
-       from_right ? (*sep > str) : ((*sep < end) && (**sep != '\0'));
-       *sep = (char *)(from_right ? (str != *sep ? BLI_str_find_prev_char_utf8(*sep, str) : NULL) :
-                                    str + index)) {
+  char *suf = (char *)(str + str_len);
+  size_t index = 0;
+  for (char *sep = (char *)(from_right ? BLI_str_find_prev_char_utf8(end, str) : str);
+       from_right ? (sep > str) : ((sep < end) && (*sep != '\0'));
+       sep = (char *)(from_right ? (str != sep ? BLI_str_find_prev_char_utf8(sep, str) : NULL) :
+                                   str + index)) {
     size_t index_ofs = 0;
-    const uint c = BLI_str_utf8_as_unicode_step_or_error(*sep, (size_t)(end - *sep), &index_ofs);
-    index += index_ofs;
-
-    if (c == BLI_UTF8_ERR) {
-      *suf = *sep = NULL;
+    const uint c = BLI_str_utf8_as_unicode_step_or_error(sep, (size_t)(end - sep), &index_ofs);
+    if (UNLIKELY(c == BLI_UTF8_ERR)) {
       break;
     }
+    index += index_ofs;
 
     for (const uint *d = delim; *d != '\0'; d++) {
       if (*d == c) {
-        /* *suf is already correct in case from_right is true. */
-        if (!from_right) {
-          *suf = (char *)(str + index);
-        }
-        return (size_t)(*sep - str);
+        /* `suf` is already correct in case from_right is true. */
+        *r_sep = sep;
+        *r_suf = from_right ? suf : (char *)(str + index);
+        return (size_t)(sep - str);
       }
     }
 
-    *suf = *sep; /* Useful in 'from_right' case! */
+    suf = sep; /* Useful in 'from_right' case! */
   }
 
-  *suf = *sep = NULL;
+  *r_suf = *r_sep = NULL;
   return str_len;
 }
 
@@ -790,9 +786,9 @@ int BLI_str_utf8_offset_to_column(const char *str, int offset)
 
 int BLI_str_utf8_offset_from_column(const char *str, int column)
 {
-  int offset = 0, pos = 0, col;
+  int offset = 0, pos = 0;
   while (*(str + offset) && pos < column) {
-    col = BLI_str_utf8_char_width_safe(str + offset);
+    const int col = BLI_str_utf8_char_width_safe(str + offset);
     if (pos + col > column) {
       break;
     }
diff --git a/source/blender/blenlib/intern/system.c b/source/blender/blenlib/intern/system.c
index 35e26e0cb33..f7249e491d7 100644
--- a/source/blender/blenlib/intern/system.c
+++ b/source/blender/blenlib/intern/system.c
@@ -21,7 +21,9 @@
 
 #  include "BLI_winstuff.h"
 #else
-#  include 
+#  if defined(HAVE_EXECINFO_H)
+#    include 
+#  endif
 #  include 
 #endif
 
@@ -61,9 +63,9 @@ int BLI_cpu_support_sse2(void)
 #if !defined(_MSC_VER)
 void BLI_system_backtrace(FILE *fp)
 {
-  /* ------------- */
-  /* Linux / Apple */
-#  if defined(__linux__) || defined(__APPLE__)
+  /* ----------------------- */
+  /* If system as execinfo.h */
+#  if defined(HAVE_EXECINFO_H)
 
 #    define SIZE 100
   void *buffer[SIZE];
@@ -152,12 +154,12 @@ void BLI_hostname_get(char *buffer, size_t bufsize)
   if (gethostname(buffer, bufsize - 1) < 0) {
     BLI_strncpy(buffer, "-unknown-", bufsize);
   }
-  /* When gethostname() truncates, it doesn't guarantee the trailing \0. */
+  /* When `gethostname()` truncates, it doesn't guarantee the trailing `\0`. */
   buffer[bufsize - 1] = '\0';
 #else
   DWORD bufsize_inout = bufsize;
   if (!GetComputerName(buffer, &bufsize_inout)) {
-    strncpy(buffer, "-unknown-", bufsize);
+    BLI_strncpy(buffer, "-unknown-", bufsize);
   }
 #endif
 }
diff --git a/source/blender/blenlib/intern/task_pool.cc b/source/blender/blenlib/intern/task_pool.cc
index a29dbe95ba9..c335d04413c 100644
--- a/source/blender/blenlib/intern/task_pool.cc
+++ b/source/blender/blenlib/intern/task_pool.cc
@@ -84,11 +84,11 @@ class Task {
         free_taskdata(other.free_taskdata),
         freedata(other.freedata)
   {
-    ((Task &)other).pool = NULL;
-    ((Task &)other).run = NULL;
-    ((Task &)other).taskdata = NULL;
+    ((Task &)other).pool = nullptr;
+    ((Task &)other).run = nullptr;
+    ((Task &)other).taskdata = nullptr;
     ((Task &)other).free_taskdata = false;
-    ((Task &)other).freedata = NULL;
+    ((Task &)other).freedata = nullptr;
   }
 #else
   Task(const Task &other) = delete;
diff --git a/source/blender/blenlib/intern/task_range.cc b/source/blender/blenlib/intern/task_range.cc
index 7e405529f03..181b760bea1 100644
--- a/source/blender/blenlib/intern/task_range.cc
+++ b/source/blender/blenlib/intern/task_range.cc
@@ -12,6 +12,7 @@
 
 #include "DNA_listBase.h"
 
+#include "BLI_lazy_threading.hh"
 #include "BLI_task.h"
 #include "BLI_threads.h"
 
@@ -104,6 +105,8 @@ void BLI_task_parallel_range(const int start,
     const size_t grainsize = MAX2(settings->min_iter_per_thread, 1);
     const tbb::blocked_range range(start, stop, grainsize);
 
+    blender::lazy_threading::send_hint();
+
     if (settings->func_reduce) {
       parallel_reduce(range, task);
       if (settings->userdata_chunk) {
diff --git a/source/blender/blenlib/intern/winstuff.c b/source/blender/blenlib/intern/winstuff.c
index e90a0ee02db..7e2c5e8f1dd 100644
--- a/source/blender/blenlib/intern/winstuff.c
+++ b/source/blender/blenlib/intern/winstuff.c
@@ -63,23 +63,17 @@ bool BLI_windows_register_blend_extension(const bool background)
   char buffer[256];
 
   char BlPath[MAX_PATH];
-  char InstallDir[FILE_MAXDIR];
-  char SysDir[FILE_MAXDIR];
-  const char *ThumbHandlerDLL;
-  char RegCmd[MAX_PATH * 2];
   char MBox[256];
-  char *blender_app;
-#  ifndef _WIN64
-  BOOL IsWOW64;
-#  endif
 
   printf("Registering file extension...");
   GetModuleFileName(0, BlPath, MAX_PATH);
 
   /* Replace the actual app name with the wrapper. */
-  blender_app = strstr(BlPath, "blender.exe");
-  if (blender_app != NULL) {
-    strcpy(blender_app, "blender-launcher.exe");
+  {
+    char *blender_app = strstr(BlPath, "blender.exe");
+    if (blender_app != NULL) {
+      strcpy(blender_app, "blender-launcher.exe");
+    }
   }
 
   /* root is HKLM by default */
@@ -157,12 +151,17 @@ bool BLI_windows_register_blend_extension(const bool background)
   }
 
 #  ifdef WITH_BLENDER_THUMBNAILER
-  BLI_windows_get_executable_dir(InstallDir);
-  GetSystemDirectory(SysDir, FILE_MAXDIR);
-  ThumbHandlerDLL = "BlendThumb.dll";
-  snprintf(
-      RegCmd, MAX_PATH * 2, "%s\\regsvr32 /s \"%s\\%s\"", SysDir, InstallDir, ThumbHandlerDLL);
-  system(RegCmd);
+  {
+    char RegCmd[MAX_PATH * 2];
+    char InstallDir[FILE_MAXDIR];
+    char SysDir[FILE_MAXDIR];
+    BLI_windows_get_executable_dir(InstallDir);
+    GetSystemDirectory(SysDir, FILE_MAXDIR);
+    const char *ThumbHandlerDLL = "BlendThumb.dll";
+    snprintf(
+        RegCmd, MAX_PATH * 2, "%s\\regsvr32 /s \"%s\\%s\"", SysDir, InstallDir, ThumbHandlerDLL);
+    system(RegCmd);
+  }
 #  endif
 
   RegCloseKey(root);
diff --git a/source/blender/blenlib/tests/BLI_array_store_test.cc b/source/blender/blenlib/tests/BLI_array_store_test.cc
index 20e2a4d88f8..5d05e3be1f3 100644
--- a/source/blender/blenlib/tests/BLI_array_store_test.cc
+++ b/source/blender/blenlib/tests/BLI_array_store_test.cc
@@ -181,7 +181,7 @@ static void testbuffer_list_state_from_data__stride_expand(ListBase *lb,
 #define TESTBUFFER_STRINGS_CREATE(lb, ...) \
   { \
     BLI_listbase_clear(lb); \
-    const char *data_array[] = {__VA_ARGS__ NULL}; \
+    const char *data_array[] = {__VA_ARGS__ nullptr}; \
     testbuffer_list_state_from_string_array((lb), data_array); \
   } \
   ((void)0)
@@ -795,10 +795,10 @@ TEST(array_store, TestChunk_Rand31_Stride11_Chunk21)
 
 /* Test From Files (disabled, keep for local tests.) */
 
-void *file_read_binary_as_mem(const char *filepath, size_t pad_bytes, size_t *r_size)
+static void *file_read_binary_as_mem(const char *filepath, size_t pad_bytes, size_t *r_size)
 {
   FILE *fp = fopen(filepath, "rb");
-  void *mem = NULL;
+  void *mem = nullptr;
 
   if (fp) {
     long int filelen_read;
@@ -810,14 +810,14 @@ void *file_read_binary_as_mem(const char *filepath, size_t pad_bytes, size_t *r_
     fseek(fp, 0L, SEEK_SET);
 
     mem = MEM_mallocN(filelen + pad_bytes, __func__);
-    if (mem == NULL) {
+    if (mem == nullptr) {
       goto finally;
     }
 
     filelen_read = fread(mem, 1, filelen, fp);
     if ((filelen_read != filelen) || ferror(fp)) {
       MEM_freeN(mem);
-      mem = NULL;
+      mem = nullptr;
       goto finally;
     }
 
diff --git a/source/blender/blenlib/tests/BLI_bit_vector_test.cc b/source/blender/blenlib/tests/BLI_bit_vector_test.cc
new file mode 100644
index 00000000000..210f2be012d
--- /dev/null
+++ b/source/blender/blenlib/tests/BLI_bit_vector_test.cc
@@ -0,0 +1,186 @@
+/* SPDX-License-Identifier: Apache-2.0 */
+
+#include "BLI_bit_vector.hh"
+#include "BLI_exception_safety_test_utils.hh"
+#include "BLI_strict_flags.h"
+
+#include "testing/testing.h"
+
+namespace blender::tests {
+
+TEST(bit_vector, DefaultConstructor)
+{
+  BitVector vec;
+  EXPECT_EQ(vec.size(), 0);
+}
+
+TEST(bit_vector, CopyConstructorInline)
+{
+  BitVector<> vec({false, false, true, true, false});
+  BitVector<> vec2 = vec;
+
+  EXPECT_EQ(vec.size(), 5);
+  EXPECT_EQ(vec2.size(), 5);
+
+  vec2[1].set();
+  EXPECT_FALSE(vec[1]);
+
+  EXPECT_FALSE(vec2[0]);
+  EXPECT_TRUE(vec2[1]);
+  EXPECT_TRUE(vec2[2]);
+  EXPECT_TRUE(vec2[3]);
+  EXPECT_FALSE(vec2[4]);
+}
+
+TEST(bit_vector, CopyConstructorLarge)
+{
+  BitVector<> vec(500, false);
+  vec[1].set();
+
+  BitVector<> vec2 = vec;
+
+  EXPECT_EQ(vec.size(), 500);
+  EXPECT_EQ(vec2.size(), 500);
+
+  vec2[2].set();
+  EXPECT_FALSE(vec[2]);
+
+  EXPECT_FALSE(vec2[0]);
+  EXPECT_TRUE(vec2[1]);
+  EXPECT_TRUE(vec2[2]);
+}
+
+TEST(bit_vector, MoveConstructorInline)
+{
+  BitVector<> vec({false, false, true, true, false});
+  BitVector<> vec2 = std::move(vec);
+
+  EXPECT_EQ(vec.size(), 0);
+  EXPECT_EQ(vec2.size(), 5);
+
+  EXPECT_FALSE(vec2[0]);
+  EXPECT_FALSE(vec2[1]);
+  EXPECT_TRUE(vec2[2]);
+  EXPECT_TRUE(vec2[3]);
+  EXPECT_FALSE(vec2[4]);
+}
+
+TEST(bit_vector, MoveConstructorLarge)
+{
+  BitVector<> vec(500, false);
+  vec[3].set();
+
+  BitVector<> vec2 = std::move(vec);
+
+  EXPECT_EQ(vec.size(), 0);
+  EXPECT_EQ(vec2.size(), 500);
+
+  EXPECT_FALSE(vec2[0]);
+  EXPECT_FALSE(vec2[1]);
+  EXPECT_FALSE(vec2[2]);
+  EXPECT_TRUE(vec2[3]);
+  EXPECT_FALSE(vec2[4]);
+}
+
+TEST(bit_vector, SizeConstructor)
+{
+  {
+    BitVector<> vec(0);
+    EXPECT_EQ(vec.size(), 0);
+  }
+  {
+    BitVector<> vec(5);
+    EXPECT_EQ(vec.size(), 5);
+    for (BitRef bit : vec) {
+      EXPECT_FALSE(bit);
+    }
+  }
+  {
+    BitVector<> vec(123);
+    EXPECT_EQ(vec.size(), 123);
+    for (BitRef bit : vec) {
+      EXPECT_FALSE(bit);
+    }
+  }
+}
+
+TEST(bit_vector, SizeFillConstructor)
+{
+  {
+    BitVector<> vec(5, false);
+    for (const int64_t i : IndexRange(5)) {
+      EXPECT_FALSE(vec[i]);
+    }
+  }
+  {
+    BitVector<> vec(123, true);
+    for (const int64_t i : IndexRange(123)) {
+      EXPECT_TRUE(vec[i]);
+    }
+  }
+}
+
+TEST(bit_vector, IndexAccess)
+{
+  BitVector<> vec(100, false);
+  vec[55].set();
+  EXPECT_FALSE(vec[50]);
+  EXPECT_FALSE(vec[51]);
+  EXPECT_FALSE(vec[52]);
+  EXPECT_FALSE(vec[53]);
+  EXPECT_FALSE(vec[54]);
+  EXPECT_TRUE(vec[55]);
+  EXPECT_FALSE(vec[56]);
+  EXPECT_FALSE(vec[57]);
+  EXPECT_FALSE(vec[58]);
+}
+
+TEST(bit_vector, Iterator)
+{
+  BitVector<> vec(100, false);
+  {
+    int64_t index = 0;
+    for (MutableBitRef bit : vec) {
+      bit.set(ELEM(index, 0, 4, 7, 10, 11));
+      index++;
+    }
+  }
+  {
+    int64_t index = 0;
+    for (BitRef bit : const_cast &>(vec)) {
+      EXPECT_EQ(bit, ELEM(index, 0, 4, 7, 10, 11));
+      index++;
+    }
+  }
+}
+
+TEST(bit_vector, Append)
+{
+  BitVector<> vec;
+  vec.append(false);
+  vec.append(true);
+  vec.append(true);
+  vec.append(false);
+
+  EXPECT_EQ(vec.size(), 4);
+  EXPECT_FALSE(vec[0]);
+  EXPECT_TRUE(vec[1]);
+  EXPECT_TRUE(vec[2]);
+  EXPECT_FALSE(vec[3]);
+}
+
+TEST(bit_vector, AppendMany)
+{
+  BitVector<> vec;
+  for (const int64_t i : IndexRange(1000)) {
+    vec.append(i % 2);
+  }
+  EXPECT_FALSE(vec[0]);
+  EXPECT_TRUE(vec[1]);
+  EXPECT_FALSE(vec[2]);
+  EXPECT_TRUE(vec[3]);
+  EXPECT_FALSE(vec[4]);
+  EXPECT_TRUE(vec[5]);
+}
+
+}  // namespace blender::tests
diff --git a/source/blender/blenlib/tests/BLI_bitmap_test.cc b/source/blender/blenlib/tests/BLI_bitmap_test.cc
new file mode 100644
index 00000000000..fb9e03e3136
--- /dev/null
+++ b/source/blender/blenlib/tests/BLI_bitmap_test.cc
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: Apache-2.0 */
+
+#include "BLI_bitmap.h"
+#include "testing/testing.h"
+
+namespace blender::tests {
+
+TEST(bitmap, empty_is_all_unset)
+{
+  BLI_BITMAP_DECLARE(bitmap, 10);
+  for (int i = 0; i < 10; ++i) {
+    EXPECT_FALSE(BLI_BITMAP_TEST_BOOL(bitmap, i));
+  }
+}
+
+TEST(bitmap, find_first_unset_empty)
+{
+  BLI_BITMAP_DECLARE(bitmap, 10);
+  EXPECT_EQ(0, BLI_bitmap_find_first_unset(bitmap, 10));
+}
+
+TEST(bitmap, find_first_unset_full)
+{
+  BLI_BITMAP_DECLARE(bitmap, 10);
+  BLI_bitmap_flip_all(bitmap, 10);
+  EXPECT_EQ(-1, BLI_bitmap_find_first_unset(bitmap, 10));
+}
+
+TEST(bitmap, find_first_unset_middle)
+{
+  BLI_BITMAP_DECLARE(bitmap, 100);
+  BLI_bitmap_flip_all(bitmap, 100);
+  /* Turn some bits off */
+  BLI_BITMAP_DISABLE(bitmap, 53);
+  BLI_BITMAP_DISABLE(bitmap, 81);
+  BLI_BITMAP_DISABLE(bitmap, 85);
+  BLI_BITMAP_DISABLE(bitmap, 86);
+
+  /* Find lowest unset bit, and set it. */
+  EXPECT_EQ(53, BLI_bitmap_find_first_unset(bitmap, 100));
+  BLI_BITMAP_ENABLE(bitmap, 53);
+  /* Now should find the next lowest bit. */
+  EXPECT_EQ(81, BLI_bitmap_find_first_unset(bitmap, 100));
+}
+
+}  // namespace blender::tests
diff --git a/source/blender/blenlib/tests/BLI_float3x3_test.cc b/source/blender/blenlib/tests/BLI_float3x3_test.cc
index d22993ee69e..cd823b6e368 100644
--- a/source/blender/blenlib/tests/BLI_float3x3_test.cc
+++ b/source/blender/blenlib/tests/BLI_float3x3_test.cc
@@ -34,6 +34,15 @@ TEST(float3x3, Rotation)
   EXPECT_FLOAT_EQ(result[1], 1.0f);
 }
 
+TEST(float3x3, Scale)
+{
+  float2 point(1.0f, 2.0f);
+  float3x3 transformation = float3x3::from_scale(float2(2.0f, 3.0f));
+  float2 result = transformation * point;
+  EXPECT_FLOAT_EQ(result[0], 2.0f);
+  EXPECT_FLOAT_EQ(result[1], 6.0f);
+}
+
 TEST(float3x3, TranslationRotationScale)
 {
   float2 point(1.0f, 2.0f);
@@ -116,4 +125,11 @@ TEST(float3x3, Origin)
   EXPECT_FLOAT_EQ(result[1], 3.0f);
 }
 
+TEST(float3x3, GetScale2D)
+{
+  float2 scale(2.0f, 3.0f);
+  float3x3 transformation = float3x3::from_scale(scale);
+  EXPECT_EQ(scale, transformation.scale_2d());
+}
+
 }  // namespace blender::tests
diff --git a/source/blender/blenlib/tests/BLI_index_range_test.cc b/source/blender/blenlib/tests/BLI_index_range_test.cc
index 10f6784cd44..8ec7ad85d9c 100644
--- a/source/blender/blenlib/tests/BLI_index_range_test.cc
+++ b/source/blender/blenlib/tests/BLI_index_range_test.cc
@@ -105,6 +105,12 @@ TEST(index_range, OneAfterEnd)
   EXPECT_EQ(range.one_after_last(), 8);
 }
 
+TEST(index_range, OneBeforeStart)
+{
+  IndexRange range = IndexRange(5, 3);
+  EXPECT_EQ(range.one_before_start(), 4);
+}
+
 TEST(index_range, Start)
 {
   IndexRange range = IndexRange(6, 2);
@@ -120,6 +126,17 @@ TEST(index_range, Slice)
   EXPECT_EQ(slice.last(), 12);
 }
 
+TEST(index_range, Intersect)
+{
+  IndexRange range = IndexRange(5, 15);
+  EXPECT_EQ(range.intersect(IndexRange(2, 2)), IndexRange(5, 0));
+  EXPECT_EQ(range.intersect(IndexRange(4, 2)), IndexRange(5, 1));
+  EXPECT_EQ(range.intersect(IndexRange(3, 20)), IndexRange(5, 15));
+  EXPECT_EQ(range.intersect(IndexRange(5, 15)), IndexRange(5, 15));
+  EXPECT_EQ(range.intersect(IndexRange(15, 10)), IndexRange(15, 5));
+  EXPECT_EQ(range.intersect(IndexRange(22, 2)), IndexRange(20, 0));
+}
+
 TEST(index_range, SliceRange)
 {
   IndexRange range = IndexRange(5, 15);
@@ -229,4 +246,50 @@ TEST(index_range, GenericAlgorithms)
   EXPECT_EQ(std::count_if(range.begin(), range.end(), [](int v) { return v < 7; }), 3);
 }
 
+TEST(index_range, SplitByAlignment)
+{
+  {
+    AlignedIndexRanges ranges = split_index_range_by_alignment(IndexRange(0, 0), 16);
+    EXPECT_EQ(ranges.prefix, IndexRange());
+    EXPECT_EQ(ranges.aligned, IndexRange());
+    EXPECT_EQ(ranges.suffix, IndexRange());
+  }
+  {
+    AlignedIndexRanges ranges = split_index_range_by_alignment(IndexRange(0, 24), 8);
+    EXPECT_EQ(ranges.prefix, IndexRange());
+    EXPECT_EQ(ranges.aligned, IndexRange(0, 24));
+    EXPECT_EQ(ranges.suffix, IndexRange());
+  }
+  {
+    AlignedIndexRanges ranges = split_index_range_by_alignment(IndexRange(1, 2), 4);
+    EXPECT_EQ(ranges.prefix, IndexRange(1, 2));
+    EXPECT_EQ(ranges.aligned, IndexRange());
+    EXPECT_EQ(ranges.suffix, IndexRange());
+  }
+  {
+    AlignedIndexRanges ranges = split_index_range_by_alignment(IndexRange(3, 50), 8);
+    EXPECT_EQ(ranges.prefix, IndexRange(3, 5));
+    EXPECT_EQ(ranges.aligned, IndexRange(8, 40));
+    EXPECT_EQ(ranges.suffix, IndexRange(48, 5));
+  }
+  {
+    AlignedIndexRanges ranges = split_index_range_by_alignment(IndexRange(3, 50), 1);
+    EXPECT_EQ(ranges.prefix, IndexRange());
+    EXPECT_EQ(ranges.aligned, IndexRange(3, 50));
+    EXPECT_EQ(ranges.suffix, IndexRange());
+  }
+  {
+    AlignedIndexRanges ranges = split_index_range_by_alignment(IndexRange(64, 16), 16);
+    EXPECT_EQ(ranges.prefix, IndexRange());
+    EXPECT_EQ(ranges.aligned, IndexRange(64, 16));
+    EXPECT_EQ(ranges.suffix, IndexRange());
+  }
+  {
+    AlignedIndexRanges ranges = split_index_range_by_alignment(IndexRange(3, 5), 8);
+    EXPECT_EQ(ranges.prefix, IndexRange(3, 5));
+    EXPECT_EQ(ranges.aligned, IndexRange());
+    EXPECT_EQ(ranges.suffix, IndexRange());
+  }
+}
+
 }  // namespace blender::tests
diff --git a/source/blender/blenlib/tests/BLI_length_parameterize_test.cc b/source/blender/blenlib/tests/BLI_length_parameterize_test.cc
index 11f4997f563..3b41a7aed0c 100644
--- a/source/blender/blenlib/tests/BLI_length_parameterize_test.cc
+++ b/source/blender/blenlib/tests/BLI_length_parameterize_test.cc
@@ -32,7 +32,7 @@ TEST(length_parameterize, FloatSimple)
   Array factors(4);
   sample_uniform(lengths, true, indices, factors);
   Array results(4);
-  linear_interpolation(values, indices, factors, results);
+  interpolate(values, indices, factors, results);
   Array expected({
       0.0f,
       1.33333f,
@@ -54,7 +54,7 @@ TEST(length_parameterize, Float)
   Array factors(20);
   sample_uniform(lengths, true, indices, factors);
   Array results(20);
-  linear_interpolation(values, indices, factors, results);
+  interpolate(values, indices, factors, results);
   Array expected({
       1.0f,     1.47368f, 1.94737f, 2.42105f, 2.89474f, 3.36842f, 3.84211f,
       4.31579f, 4.78947f, 5.26316f, 5.73684f, 6.21053f, 6.68421f, 7.1579f,
@@ -75,7 +75,7 @@ TEST(length_parameterize, Float2)
   Array factors(12);
   sample_uniform(lengths, true, indices, factors);
   Array results(12);
-  linear_interpolation(values, indices, factors, results);
+  interpolate(values, indices, factors, results);
   Array expected({
       {0.0f, 0.0f},
       {0.272727f, 0.0f},
@@ -105,7 +105,7 @@ TEST(length_parameterize, Float2Cyclic)
   Array factors(12);
   sample_uniform(lengths, false, indices, factors);
   Array results(12);
-  linear_interpolation(values, indices, factors, results);
+  interpolate(values, indices, factors, results);
   Array expected({
       {0.0f, 0.0f},
       {0.333333f, 0.0f},
@@ -135,7 +135,7 @@ TEST(length_parameterize, LineMany)
   Array factors(5007);
   sample_uniform(lengths, true, indices, factors);
   Array results(5007);
-  linear_interpolation(values, indices, factors, results);
+  interpolate(values, indices, factors, results);
   Array expected({
       1.9962f, 1.9964f, 1.9966f, 1.9968f, 1.997f, 1.9972f, 1.9974f, 1.9976f, 1.9978f, 1.998f,
       1.9982f, 1.9984f, 1.9986f, 1.9988f, 1.999f, 1.9992f, 1.9994f, 1.9996f, 1.9998f, 2.0f,
@@ -154,7 +154,7 @@ TEST(length_parameterize, CyclicMany)
   Array factors(5007);
   sample_uniform(lengths, false, indices, factors);
   Array results(5007);
-  linear_interpolation(values, indices, factors, results);
+  interpolate(values, indices, factors, results);
   Array expected({
       {0, 0.0159776},  {0, 0.0151787},  {0, 0.0143797},  {0, 0.013581},   {0, 0.0127821},
       {0, 0.0119832},  {0, 0.0111842},  {0, 0.0103855},  {0, 0.00958657}, {0, 0.00878763},
@@ -178,7 +178,7 @@ TEST(length_parameterize, InterpolateColor)
   Array factors(10);
   sample_uniform(lengths, false, indices, factors);
   Array results(10);
-  linear_interpolation(colors, indices, factors, results);
+  interpolate(colors, indices, factors, results);
   Array expected({
       {0, 0, 0, 1},
       {0.4, 0, 0, 1},
@@ -209,8 +209,7 @@ TEST(length_parameterize, ArbitraryFloatSimple)
   Array factors(4);
   sample_at_lengths(lengths, sample_lengths, indices, factors);
   Array results(4);
-  linear_interpolation(values, indices, factors, results);
-  results.as_span().print_as_lines("results");
+  interpolate(values, indices, factors, results);
   Array expected({
       0.5f,
       1.5f,
@@ -233,8 +232,7 @@ TEST(length_parameterize, ArbitraryFloat2)
   Array factors(12);
   sample_at_lengths(lengths, sample_lengths, indices, factors);
   Array results(12);
-  linear_interpolation(values, indices, factors, results);
-  results.as_span().print_as_lines("results");
+  interpolate(values, indices, factors, results);
   Array expected({
       {0.5f, 0.0f},
       {1.0f, 0.5f},
diff --git a/source/blender/blenlib/tests/BLI_math_rotation_test.cc b/source/blender/blenlib/tests/BLI_math_rotation_test.cc
index a283118bea2..460cfd2d36c 100644
--- a/source/blender/blenlib/tests/BLI_math_rotation_test.cc
+++ b/source/blender/blenlib/tests/BLI_math_rotation_test.cc
@@ -7,6 +7,8 @@
 #include "BLI_math_rotation.hh"
 #include "BLI_math_vector.hh"
 
+#include "BLI_vector.hh"
+
 #include 
 
 /* Test that quaternion converts to itself via matrix. */
@@ -150,6 +152,107 @@ TEST(math_rotation, quat_split_swing_and_twist_negative)
   EXPECT_V4_NEAR(twist, expected_twist, FLT_EPSILON);
 }
 
+/* -------------------------------------------------------------------- */
+/** \name Test `sin_cos_from_fraction` Accuracy & Exact Symmetry
+ * \{ */
+
+static void test_sin_cos_from_fraction_accuracy(const int range, const float expected_eps)
+{
+  for (int i = 0; i < range; i++) {
+    float sin_cos_fl[2];
+    sin_cos_from_fraction(i, range, &sin_cos_fl[0], &sin_cos_fl[1]);
+    const float phi = (float)(2.0 * M_PI) * ((float)i / (float)range);
+    const float sin_cos_test_fl[2] = {sinf(phi), cosf(phi)};
+    EXPECT_V2_NEAR(sin_cos_fl, sin_cos_test_fl, expected_eps);
+  }
+}
+
+/** Ensure the result of #sin_cos_from_fraction match #sinf & #cosf. */
+TEST(math_rotation, sin_cos_from_fraction_accuracy)
+{
+  for (int range = 1; range <= 64; range++) {
+    test_sin_cos_from_fraction_accuracy(range, 1e-6f);
+  }
+}
+
+/** Ensure values are exactly symmetrical where possible. */
+static void test_sin_cos_from_fraction_symmetry(const int range)
+{
+  /* The expected number of unique numbers depends on the range being a multiple of 4/2/1. */
+  const enum {
+    MULTIPLE_OF_1 = 1,
+    MULTIPLE_OF_2 = 2,
+    MULTIPLE_OF_4 = 3,
+  } multiple_of = (range & 1) ? MULTIPLE_OF_1 : ((range & 3) ? MULTIPLE_OF_2 : MULTIPLE_OF_4);
+
+  blender::Vector coords;
+  coords.reserve(range);
+  for (int i = 0; i < range; i++) {
+    float sin_cos_fl[2];
+    sin_cos_from_fraction(i, range, &sin_cos_fl[0], &sin_cos_fl[1]);
+    switch (multiple_of) {
+      case MULTIPLE_OF_1: {
+        sin_cos_fl[0] = fabsf(sin_cos_fl[0]);
+        break;
+      }
+      case MULTIPLE_OF_2: {
+        sin_cos_fl[0] = fabsf(sin_cos_fl[0]);
+        sin_cos_fl[1] = fabsf(sin_cos_fl[1]);
+        break;
+      }
+      case MULTIPLE_OF_4: {
+        sin_cos_fl[0] = fabsf(sin_cos_fl[0]);
+        sin_cos_fl[1] = fabsf(sin_cos_fl[1]);
+        if (sin_cos_fl[0] > sin_cos_fl[1]) {
+          SWAP(float, sin_cos_fl[0], sin_cos_fl[1]);
+        }
+        break;
+      }
+    }
+    coords.append_unchecked(sin_cos_fl);
+  }
+  /* Sort, then count unique items. */
+  std::sort(coords.begin(), coords.end(), [](const blender::float2 &a, const blender::float2 &b) {
+    float delta = b[0] - a[0];
+    if (delta == 0.0f) {
+      delta = b[1] - a[1];
+    }
+    return delta > 0.0f;
+  });
+  int unique_coords_count = 1;
+  if (range > 1) {
+    int i_prev = 0;
+    for (int i = 1; i < range; i_prev = i++) {
+      if (coords[i_prev] != coords[i]) {
+        unique_coords_count += 1;
+      }
+    }
+  }
+  switch (multiple_of) {
+    case MULTIPLE_OF_1: {
+      EXPECT_EQ(unique_coords_count, (range / 2) + 1);
+      break;
+    }
+    case MULTIPLE_OF_2: {
+      EXPECT_EQ(unique_coords_count, (range / 4) + 1);
+      break;
+    }
+    case MULTIPLE_OF_4: {
+      EXPECT_EQ(unique_coords_count, (range / 8) + 1);
+      break;
+    }
+  }
+}
+
+TEST(math_rotation, sin_cos_from_fraction_symmetry)
+{
+  for (int range = 1; range <= 64; range++) {
+    test_sin_cos_from_fraction_symmetry(range);
+  }
+}
+
+/** \} */
+
 namespace blender::math::tests {
 
 TEST(math_rotation, RotateDirectionAroundAxis)
diff --git a/source/blender/blenlib/tests/BLI_path_util_test.cc b/source/blender/blenlib/tests/BLI_path_util_test.cc
index 4f6f4a5c413..54afc3d975d 100644
--- a/source/blender/blenlib/tests/BLI_path_util_test.cc
+++ b/source/blender/blenlib/tests/BLI_path_util_test.cc
@@ -298,6 +298,13 @@ TEST(path_util, JoinComplex)
   JOIN("1/2/3/", 100, "1", "////////", "", "2", "3\\");
 }
 
+TEST(path_util, JoinRelativePrefix)
+{
+  JOIN("//a/b/c", 100, "//a", "b", "c");
+  JOIN("//a/b/c", 100, "//", "//a//", "//b//", "//c");
+  JOIN("//a/b/c", 100, "//", "//", "a", "//", "b", "//", "c");
+}
+
 #undef JOIN
 
 /* BLI_path_frame */
diff --git a/source/blender/blenlib/tests/BLI_pool_test.cc b/source/blender/blenlib/tests/BLI_pool_test.cc
new file mode 100644
index 00000000000..31cb255d997
--- /dev/null
+++ b/source/blender/blenlib/tests/BLI_pool_test.cc
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: Apache-2.0 */
+
+#include "BLI_exception_safety_test_utils.hh"
+#include "BLI_pool.hh"
+#include "BLI_strict_flags.h"
+#include "testing/testing.h"
+
+namespace blender::tests {
+
+TEST(pool, DefaultConstructor)
+{
+  Pool pool;
+  EXPECT_EQ(pool.size(), 0);
+}
+
+TEST(pool, Allocation)
+{
+  Vector ptrs;
+  Pool pool;
+  for (int i = 0; i < 100; i++) {
+    ptrs.append(&pool.construct(i));
+  }
+  EXPECT_EQ(pool.size(), 100);
+
+  for (int *ptr : ptrs) {
+    pool.destruct(*ptr);
+  }
+  EXPECT_EQ(pool.size(), 0);
+}
+
+TEST(pool, Reuse)
+{
+  Vector ptrs;
+  Pool pool;
+  for (int i = 0; i < 32; i++) {
+    ptrs.append(&pool.construct(i));
+  }
+
+  int *freed_ptr = ptrs[6];
+  pool.destruct(*freed_ptr);
+
+  ptrs[6] = &pool.construct(0);
+
+  EXPECT_EQ(ptrs[6], freed_ptr);
+
+  for (int *ptr : ptrs) {
+    pool.destruct(*ptr);
+  }
+}
+
+}  // namespace blender::tests
diff --git a/source/blender/blenlib/tests/BLI_set_test.cc b/source/blender/blenlib/tests/BLI_set_test.cc
index 5a97b2c7999..9dfa48b5822 100644
--- a/source/blender/blenlib/tests/BLI_set_test.cc
+++ b/source/blender/blenlib/tests/BLI_set_test.cc
@@ -532,8 +532,14 @@ TEST(set, ForwardIterator)
   Set::iterator iter1 = set.begin();
   int value1 = *iter1;
   Set::iterator iter2 = iter1++;
-  EXPECT_EQ(*iter1, value1);
-  EXPECT_EQ(*iter2, *(++iter1));
+  EXPECT_EQ(*iter2, value1);
+  EXPECT_EQ(*(++iter2), *iter1);
+  /* Interesting find: On GCC & MSVC this will succeed, as the 2nd argument is evaluated before the
+   * 1st. On Apple Clang it's the other way around, and the test fails. */
+  // EXPECT_EQ(*iter1, *(++iter1));
+  Set::iterator iter3 = ++iter1;
+  /* Check that #iter1 itself changed. */
+  EXPECT_EQ(*iter3, *iter1);
 }
 
 TEST(set, GenericAlgorithms)
diff --git a/source/blender/blenlib/tests/BLI_string_search_test.cc b/source/blender/blenlib/tests/BLI_string_search_test.cc
index aa6adae8d76..ab1d073ed33 100644
--- a/source/blender/blenlib/tests/BLI_string_search_test.cc
+++ b/source/blender/blenlib/tests/BLI_string_search_test.cc
@@ -9,7 +9,7 @@
 namespace blender::string_search::tests {
 
 /* Right arrow, keep in sync with #UI_MENU_ARROW_SEP in `UI_interface.h`. */
-#define UI_MENU_ARROW_SEP "\xe2\x96\xb6"
+#define UI_MENU_ARROW_SEP "\xe2\x96\xb8"
 
 TEST(string_search, damerau_levenshtein_distance)
 {
diff --git a/source/blender/blenlib/tests/BLI_vector_test.cc b/source/blender/blenlib/tests/BLI_vector_test.cc
index 3a12fe14de3..bbc4cecee4a 100644
--- a/source/blender/blenlib/tests/BLI_vector_test.cc
+++ b/source/blender/blenlib/tests/BLI_vector_test.cc
@@ -416,7 +416,7 @@ TEST(vector, Remove)
   vec.remove(1);
   EXPECT_TRUE(std::equal(vec.begin(), vec.end(), Span({2}).begin()));
   vec.remove(0);
-  EXPECT_TRUE(std::equal(vec.begin(), vec.end(), Span({}).begin()));
+  EXPECT_EQ(vec.begin(), vec.end());
 }
 
 TEST(vector, ExtendSmallVector)
diff --git a/source/blender/blenlib/tests/performance/CMakeLists.txt b/source/blender/blenlib/tests/performance/CMakeLists.txt
index c4f03255a11..2e4fcd4516c 100644
--- a/source/blender/blenlib/tests/performance/CMakeLists.txt
+++ b/source/blender/blenlib/tests/performance/CMakeLists.txt
@@ -4,6 +4,10 @@
 set(INC
   .
   ..
+  ../..
+  ../../../makesdna
+  ../../../../../intern/guardedalloc
+  ../../../../../intern/atomic
 )
 
 include_directories(${INC})
diff --git a/source/blender/blenloader/BLO_blend_validate.h b/source/blender/blenloader/BLO_blend_validate.h
index 0ce40987adc..4594f730758 100644
--- a/source/blender/blenloader/BLO_blend_validate.h
+++ b/source/blender/blenloader/BLO_blend_validate.h
@@ -12,6 +12,10 @@
 struct Main;
 struct ReportList;
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /**
  * Check (but do *not* fix) that all linked data-blocks are still valid
  * (i.e. pointing to the right library).
@@ -21,3 +25,7 @@ bool BLO_main_validate_libraries(struct Main *bmain, struct ReportList *reports)
  * * Check (and fix if needed) that shape key's 'from' pointer is valid.
  */
 bool BLO_main_validate_shapekeys(struct Main *bmain, struct ReportList *reports);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/source/blender/blenloader/BLO_read_write.h b/source/blender/blenloader/BLO_read_write.h
index 536c3989aff..6f39670a226 100644
--- a/source/blender/blenloader/BLO_read_write.h
+++ b/source/blender/blenloader/BLO_read_write.h
@@ -219,8 +219,8 @@ void *BLO_read_get_new_packed_address(BlendDataReader *reader, const void *old_a
 
 typedef void (*BlendReadListFn)(BlendDataReader *reader, void *data);
 /**
- * Updates all ->prev and ->next pointers of the list elements.
- * Updates the list->first and list->last pointers.
+ * Updates all `->prev` and `->next` pointers of the list elements.
+ * Updates the `list->first` and `list->last` pointers.
  * When not NULL, calls the callback on every element.
  */
 void BLO_read_list_cb(BlendDataReader *reader, struct ListBase *list, BlendReadListFn callback);
@@ -237,6 +237,7 @@ void BLO_read_pointer_array(BlendDataReader *reader, void **ptr_p);
 
 /* Misc. */
 
+int BLO_read_fileversion_get(BlendDataReader *reader);
 bool BLO_read_requires_endian_switch(BlendDataReader *reader);
 bool BLO_read_data_is_undo(BlendDataReader *reader);
 void BLO_read_data_globmap_add(BlendDataReader *reader, void *oldaddr, void *newaddr);
diff --git a/source/blender/blenloader/BLO_readfile.h b/source/blender/blenloader/BLO_readfile.h
index 043f9ffd723..93040fa01ee 100644
--- a/source/blender/blenloader/BLO_readfile.h
+++ b/source/blender/blenloader/BLO_readfile.h
@@ -229,10 +229,10 @@ struct LinkNode *BLO_blendhandle_get_datablock_names(BlendHandle *bh,
  * \return A BLI_linklist of `BLODataBlockInfo *`.
  * The links and #BLODataBlockInfo.asset_data should be freed with MEM_freeN.
  */
-struct LinkNode * /*BLODataBlockInfo */ BLO_blendhandle_get_datablock_info(BlendHandle *bh,
-                                                                           int ofblocktype,
-                                                                           bool use_assets_only,
-                                                                           int *r_tot_info_items);
+struct LinkNode * /*BLODataBlockInfo*/ BLO_blendhandle_get_datablock_info(BlendHandle *bh,
+                                                                          int ofblocktype,
+                                                                          bool use_assets_only,
+                                                                          int *r_tot_info_items);
 /**
  * Gets the previews of all the data-blocks in a file of a certain type
  * (e.g. all the scene previews in a file).
diff --git a/source/blender/blenloader/BLO_undofile.h b/source/blender/blenloader/BLO_undofile.h
index 0584f95d85f..0dee167db53 100644
--- a/source/blender/blenloader/BLO_undofile.h
+++ b/source/blender/blenloader/BLO_undofile.h
@@ -61,6 +61,10 @@ typedef struct {
   bool memchunk_identical;
 } UndoReader;
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Actually only used `writefile.c`. */
 
 void BLO_memfile_write_init(MemFileWriteData *mem_data,
@@ -101,3 +105,7 @@ extern struct Main *BLO_memfile_main_get(struct MemFile *memfile,
 extern bool BLO_memfile_write_file(struct MemFile *memfile, const char *filepath);
 
 FileReader *BLO_memfile_new_filereader(MemFile *memfile, int undo_direction);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/source/blender/blenloader/CMakeLists.txt b/source/blender/blenloader/CMakeLists.txt
index 5ca026ae9a3..f0209d1337c 100644
--- a/source/blender/blenloader/CMakeLists.txt
+++ b/source/blender/blenloader/CMakeLists.txt
@@ -19,6 +19,7 @@ set(INC
   ../windowmanager
   ../../../intern/clog
   ../../../intern/guardedalloc
+  ../bmesh
 
   # for writefile.c: dna_type_offsets.h
   ${CMAKE_BINARY_DIR}/source/blender/makesdna/intern
@@ -32,24 +33,25 @@ set(INC_SYS
 
 set(SRC
   ${CMAKE_SOURCE_DIR}/release/datafiles/userdef/userdef_default_theme.c
-  intern/blend_validate.c
-  intern/readblenentry.c
-  intern/readfile.c
-  intern/readfile_tempload.c
-  intern/undofile.c
+  intern/blend_validate.cc
+  intern/readblenentry.cc
+  intern/readfile.cc
+  intern/readfile_tempload.cc
+  intern/undofile.cc
   intern/versioning_250.c
   intern/versioning_260.c
   intern/versioning_270.c
   intern/versioning_280.c
   intern/versioning_290.c
-  intern/versioning_300.c
+  intern/versioning_300.cc
+  intern/versioning_400.cc
   intern/versioning_common.cc
   intern/versioning_cycles.c
   intern/versioning_defaults.c
   intern/versioning_dna.c
   intern/versioning_legacy.c
   intern/versioning_userdef.c
-  intern/writefile.c
+  intern/writefile.cc
 
   BLO_blend_defs.h
   BLO_blend_validate.h
@@ -81,6 +83,17 @@ if(WITH_ALEMBIC)
   add_definitions(-DWITH_ALEMBIC)
 endif()
 
+if(WITH_TBB)
+  list(APPEND INC_SYS
+    ${TBB_INCLUDE_DIRS}
+  )
+  add_definitions(-DWITH_TBB)
+endif()
+
+if(WIN32)
+  add_definitions(-DNOMINMAX)
+endif()
+
 blender_add_lib(bf_blenloader "${SRC}" "${INC}" "${INC_SYS}" "${LIB}")
 
 # needed so writefile.c can use dna_type_offsets.h
diff --git a/source/blender/blenloader/intern/blend_validate.c b/source/blender/blenloader/intern/blend_validate.c
deleted file mode 100644
index e1527201e22..00000000000
--- a/source/blender/blenloader/intern/blend_validate.c
+++ /dev/null
@@ -1,200 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-
-/** \file
- * \ingroup blenloader
- *
- * Utils to check/validate a Main is in sane state,
- * only checks relations between data-blocks and libraries for now.
- *
- * \note Does not *fix* anything, only reports found errors.
- */
-
-#include  /* for #strrchr #strncmp #strstr */
-
-#include "BLI_utildefines.h"
-
-#include "BLI_blenlib.h"
-#include "BLI_linklist.h"
-
-#include "MEM_guardedalloc.h"
-
-#include "DNA_key_types.h"
-#include "DNA_sdna_types.h"
-#include "DNA_windowmanager_types.h"
-
-#include "BKE_key.h"
-#include "BKE_lib_id.h"
-#include "BKE_library.h"
-#include "BKE_main.h"
-#include "BKE_report.h"
-
-#include "BLO_blend_validate.h"
-#include "BLO_readfile.h"
-
-#include "readfile.h"
-
-bool BLO_main_validate_libraries(Main *bmain, ReportList *reports)
-{
-  ListBase mainlist;
-  bool is_valid = true;
-
-  BKE_main_lock(bmain);
-
-  blo_split_main(&mainlist, bmain);
-
-  ListBase *lbarray[INDEX_ID_MAX];
-  int i = set_listbasepointers(bmain, lbarray);
-  while (i--) {
-    for (ID *id = lbarray[i]->first; id != NULL; id = id->next) {
-      if (ID_IS_LINKED(id)) {
-        is_valid = false;
-        BKE_reportf(reports,
-                    RPT_ERROR,
-                    "ID %s is in local database while being linked from library %s!",
-                    id->name,
-                    id->lib->filepath);
-      }
-    }
-  }
-
-  for (Main *curmain = bmain->next; curmain != NULL; curmain = curmain->next) {
-    Library *curlib = curmain->curlib;
-    if (curlib == NULL) {
-      BKE_report(reports, RPT_ERROR, "Library database with NULL library data-block!");
-      continue;
-    }
-
-    BKE_library_filepath_set(bmain, curlib, curlib->filepath);
-    BlendFileReadReport bf_reports = {.reports = reports};
-    BlendHandle *bh = BLO_blendhandle_from_file(curlib->filepath_abs, &bf_reports);
-
-    if (bh == NULL) {
-      BKE_reportf(reports,
-                  RPT_ERROR,
-                  "Library ID %s not found at expected path %s!",
-                  curlib->id.name,
-                  curlib->filepath_abs);
-      continue;
-    }
-
-    i = set_listbasepointers(curmain, lbarray);
-    while (i--) {
-      ID *id = lbarray[i]->first;
-      if (id == NULL) {
-        continue;
-      }
-
-      if (GS(id->name) == ID_LI) {
-        is_valid = false;
-        BKE_reportf(reports,
-                    RPT_ERROR,
-                    "Library ID %s in library %s, this should not happen!",
-                    id->name,
-                    curlib->filepath);
-        continue;
-      }
-
-      int totnames = 0;
-      LinkNode *names = BLO_blendhandle_get_datablock_names(bh, GS(id->name), false, &totnames);
-      for (; id != NULL; id = id->next) {
-        if (!ID_IS_LINKED(id)) {
-          is_valid = false;
-          BKE_reportf(reports,
-                      RPT_ERROR,
-                      "ID %s has NULL lib pointer while being in library %s!",
-                      id->name,
-                      curlib->filepath);
-          continue;
-        }
-        if (id->lib != curlib) {
-          is_valid = false;
-          BKE_reportf(reports, RPT_ERROR, "ID %s has mismatched lib pointer!", id->name);
-          continue;
-        }
-
-        LinkNode *name = names;
-        for (; name; name = name->next) {
-          char *str_name = (char *)name->link;
-          if (id->name[2] == str_name[0] && STREQ(str_name, id->name + 2)) {
-            break;
-          }
-        }
-
-        if (name == NULL) {
-          is_valid = false;
-          BKE_reportf(reports,
-                      RPT_ERROR,
-                      "ID %s not found in library %s anymore!",
-                      id->name,
-                      id->lib->filepath);
-          continue;
-        }
-      }
-
-      BLI_linklist_freeN(names);
-    }
-
-    BLO_blendhandle_close(bh);
-  }
-
-  blo_join_main(&mainlist);
-
-  BLI_assert(BLI_listbase_is_single(&mainlist));
-  BLI_assert(mainlist.first == (void *)bmain);
-
-  BKE_main_unlock(bmain);
-
-  return is_valid;
-}
-
-bool BLO_main_validate_shapekeys(Main *bmain, ReportList *reports)
-{
-  ListBase *lb;
-  ID *id;
-  bool is_valid = true;
-
-  BKE_main_lock(bmain);
-
-  FOREACH_MAIN_LISTBASE_BEGIN (bmain, lb) {
-    FOREACH_MAIN_LISTBASE_ID_BEGIN (lb, id) {
-      if (!BKE_key_idtype_support(GS(id->name))) {
-        break;
-      }
-      if (!ID_IS_LINKED(id)) {
-        /* We assume lib data is valid... */
-        Key *shapekey = BKE_key_from_id(id);
-        if (shapekey != NULL && shapekey->from != id) {
-          is_valid = false;
-          BKE_reportf(reports,
-                      RPT_ERROR,
-                      "ID %s uses shapekey %s, but its 'from' pointer is invalid (%p), fixing...",
-                      id->name,
-                      shapekey->id.name,
-                      shapekey->from);
-          shapekey->from = id;
-        }
-      }
-    }
-    FOREACH_MAIN_LISTBASE_ID_END;
-  }
-  FOREACH_MAIN_LISTBASE_END;
-
-  BKE_main_unlock(bmain);
-
-  /* NOTE: #BKE_id_delete also locks `bmain`, so we need to do this loop outside of the lock here.
-   */
-  LISTBASE_FOREACH_MUTABLE (Key *, shapekey, &bmain->shapekeys) {
-    if (shapekey->from != NULL) {
-      continue;
-    }
-
-    BKE_reportf(reports,
-                RPT_ERROR,
-                "Shapekey %s has an invalid 'from' pointer (%p), it will be deleted",
-                shapekey->id.name,
-                shapekey->from);
-    BKE_id_delete(bmain, shapekey);
-  }
-
-  return is_valid;
-}
diff --git a/source/blender/blenloader/intern/blend_validate.cc b/source/blender/blenloader/intern/blend_validate.cc
new file mode 100644
index 00000000000..96314ab4324
--- /dev/null
+++ b/source/blender/blenloader/intern/blend_validate.cc
@@ -0,0 +1,202 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/** \file
+ * \ingroup blenloader
+ *
+ * Utils to check/validate a Main is in sane state,
+ * only checks relations between data-blocks and libraries for now.
+ *
+ * \note Does not *fix* anything, only reports found errors.
+ */
+
+#include  /* for #strrchr #strncmp #strstr */
+
+#include "BLI_utildefines.h"
+
+#include "BLI_blenlib.h"
+#include "BLI_linklist.h"
+
+#include "MEM_guardedalloc.h"
+
+#include "DNA_key_types.h"
+#include "DNA_sdna_types.h"
+#include "DNA_windowmanager_types.h"
+
+#include "BKE_key.h"
+#include "BKE_lib_id.h"
+#include "BKE_library.h"
+#include "BKE_main.h"
+#include "BKE_report.h"
+
+#include "BLO_blend_validate.h"
+#include "BLO_readfile.h"
+
+#include "readfile.h"
+
+bool BLO_main_validate_libraries(Main *bmain, ReportList *reports)
+{
+  ListBase mainlist;
+  bool is_valid = true;
+
+  BKE_main_lock(bmain);
+
+  blo_split_main(&mainlist, bmain);
+
+  ListBase *lbarray[INDEX_ID_MAX];
+  int i = set_listbasepointers(bmain, lbarray);
+  while (i--) {
+    for (ID *id = static_cast(lbarray[i]->first); id != nullptr;
+         id = static_cast(id->next)) {
+      if (ID_IS_LINKED(id)) {
+        is_valid = false;
+        BKE_reportf(reports,
+                    RPT_ERROR,
+                    "ID %s is in local database while being linked from library %s!",
+                    id->name,
+                    id->lib->filepath);
+      }
+    }
+  }
+
+  for (Main *curmain = bmain->next; curmain != nullptr; curmain = curmain->next) {
+    Library *curlib = curmain->curlib;
+    if (curlib == nullptr) {
+      BKE_report(reports, RPT_ERROR, "Library database with nullptr library data-block!");
+      continue;
+    }
+
+    BKE_library_filepath_set(bmain, curlib, curlib->filepath);
+    BlendFileReadReport bf_reports{};
+    bf_reports.reports = reports;
+    BlendHandle *bh = BLO_blendhandle_from_file(curlib->filepath_abs, &bf_reports);
+
+    if (bh == nullptr) {
+      BKE_reportf(reports,
+                  RPT_ERROR,
+                  "Library ID %s not found at expected path %s!",
+                  curlib->id.name,
+                  curlib->filepath_abs);
+      continue;
+    }
+
+    i = set_listbasepointers(curmain, lbarray);
+    while (i--) {
+      ID *id = static_cast(lbarray[i]->first);
+      if (id == nullptr) {
+        continue;
+      }
+
+      if (GS(id->name) == ID_LI) {
+        is_valid = false;
+        BKE_reportf(reports,
+                    RPT_ERROR,
+                    "Library ID %s in library %s, this should not happen!",
+                    id->name,
+                    curlib->filepath);
+        continue;
+      }
+
+      int totnames = 0;
+      LinkNode *names = BLO_blendhandle_get_datablock_names(bh, GS(id->name), false, &totnames);
+      for (; id != nullptr; id = static_cast(id->next)) {
+        if (!ID_IS_LINKED(id)) {
+          is_valid = false;
+          BKE_reportf(reports,
+                      RPT_ERROR,
+                      "ID %s has nullptr lib pointer while being in library %s!",
+                      id->name,
+                      curlib->filepath);
+          continue;
+        }
+        if (id->lib != curlib) {
+          is_valid = false;
+          BKE_reportf(reports, RPT_ERROR, "ID %s has mismatched lib pointer!", id->name);
+          continue;
+        }
+
+        LinkNode *name = names;
+        for (; name; name = name->next) {
+          char *str_name = (char *)name->link;
+          if (id->name[2] == str_name[0] && STREQ(str_name, id->name + 2)) {
+            break;
+          }
+        }
+
+        if (name == nullptr) {
+          is_valid = false;
+          BKE_reportf(reports,
+                      RPT_ERROR,
+                      "ID %s not found in library %s anymore!",
+                      id->name,
+                      id->lib->filepath);
+          continue;
+        }
+      }
+
+      BLI_linklist_freeN(names);
+    }
+
+    BLO_blendhandle_close(bh);
+  }
+
+  blo_join_main(&mainlist);
+
+  BLI_assert(BLI_listbase_is_single(&mainlist));
+  BLI_assert(mainlist.first == (void *)bmain);
+
+  BKE_main_unlock(bmain);
+
+  return is_valid;
+}
+
+bool BLO_main_validate_shapekeys(Main *bmain, ReportList *reports)
+{
+  ListBase *lb;
+  ID *id;
+  bool is_valid = true;
+
+  BKE_main_lock(bmain);
+
+  FOREACH_MAIN_LISTBASE_BEGIN (bmain, lb) {
+    FOREACH_MAIN_LISTBASE_ID_BEGIN (lb, id) {
+      if (!BKE_key_idtype_support(GS(id->name))) {
+        break;
+      }
+      if (!ID_IS_LINKED(id)) {
+        /* We assume lib data is valid... */
+        Key *shapekey = BKE_key_from_id(id);
+        if (shapekey != nullptr && shapekey->from != id) {
+          is_valid = false;
+          BKE_reportf(reports,
+                      RPT_ERROR,
+                      "ID %s uses shapekey %s, but its 'from' pointer is invalid (%p), fixing...",
+                      id->name,
+                      shapekey->id.name,
+                      shapekey->from);
+          shapekey->from = id;
+        }
+      }
+    }
+    FOREACH_MAIN_LISTBASE_ID_END;
+  }
+  FOREACH_MAIN_LISTBASE_END;
+
+  BKE_main_unlock(bmain);
+
+  /* NOTE: #BKE_id_delete also locks `bmain`, so we need to do this loop outside of the lock here.
+   */
+  LISTBASE_FOREACH_MUTABLE (Key *, shapekey, &bmain->shapekeys) {
+    if (shapekey->from != nullptr) {
+      continue;
+    }
+
+    BKE_reportf(reports,
+                RPT_ERROR,
+                "Shapekey %s has an invalid 'from' pointer (%p), it will be deleted",
+                shapekey->id.name,
+                shapekey->from);
+    BKE_id_delete(bmain, shapekey);
+  }
+
+  return is_valid;
+}
diff --git a/source/blender/blenloader/intern/readblenentry.c b/source/blender/blenloader/intern/readblenentry.c
deleted file mode 100644
index 1bfa3b0e2bb..00000000000
--- a/source/blender/blenloader/intern/readblenentry.c
+++ /dev/null
@@ -1,453 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later
- * Copyright 2001-2002 NaN Holding BV. All rights reserved. */
-
-/** \file
- * \ingroup blenloader
- * `.blend` file reading entry point.
- */
-
-#include 
-
-#include 
-#include 
-#include 
-#include 
-
-#include "MEM_guardedalloc.h"
-
-#include "BLI_ghash.h"
-#include "BLI_linklist.h"
-#include "BLI_listbase.h"
-#include "BLI_string.h"
-#include "BLI_utildefines.h"
-
-#include "DNA_genfile.h"
-#include "DNA_sdna_types.h"
-
-#include "BKE_icons.h"
-#include "BKE_idtype.h"
-#include "BKE_main.h"
-
-#include "BLO_blend_defs.h"
-#include "BLO_readfile.h"
-#include "BLO_undofile.h"
-
-#include "readfile.h"
-
-#include "BLI_sys_types.h" /* Needed for `intptr_t`. */
-
-#ifdef WIN32
-#  include "BLI_winstuff.h"
-#endif
-
-/* local prototypes --------------------- */
-void BLO_blendhandle_print_sizes(BlendHandle *bh, void *fp);
-
-/* Access routines used by filesel. */
-
-BlendHandle *BLO_blendhandle_from_file(const char *filepath, BlendFileReadReport *reports)
-{
-  BlendHandle *bh;
-
-  bh = (BlendHandle *)blo_filedata_from_file(filepath, reports);
-
-  return bh;
-}
-
-BlendHandle *BLO_blendhandle_from_memory(const void *mem,
-                                         int memsize,
-                                         BlendFileReadReport *reports)
-{
-  BlendHandle *bh;
-
-  bh = (BlendHandle *)blo_filedata_from_memory(mem, memsize, reports);
-
-  return bh;
-}
-
-void BLO_blendhandle_print_sizes(BlendHandle *bh, void *fp)
-{
-  FileData *fd = (FileData *)bh;
-  BHead *bhead;
-
-  fprintf(fp, "[\n");
-  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
-    if (bhead->code == ENDB) {
-      break;
-    }
-
-    const SDNA_Struct *struct_info = fd->filesdna->structs[bhead->SDNAnr];
-    const char *name = fd->filesdna->types[struct_info->type];
-    char buf[4];
-
-    buf[0] = (bhead->code >> 24) & 0xFF;
-    buf[1] = (bhead->code >> 16) & 0xFF;
-    buf[2] = (bhead->code >> 8) & 0xFF;
-    buf[3] = (bhead->code >> 0) & 0xFF;
-
-    buf[0] = buf[0] ? buf[0] : ' ';
-    buf[1] = buf[1] ? buf[1] : ' ';
-    buf[2] = buf[2] ? buf[2] : ' ';
-    buf[3] = buf[3] ? buf[3] : ' ';
-
-    fprintf(fp,
-            "['%.4s', '%s', %d, %ld ],\n",
-            buf,
-            name,
-            bhead->nr,
-            (long int)(bhead->len + sizeof(BHead)));
-  }
-  fprintf(fp, "]\n");
-}
-
-LinkNode *BLO_blendhandle_get_datablock_names(BlendHandle *bh,
-                                              int ofblocktype,
-                                              const bool use_assets_only,
-                                              int *r_tot_names)
-{
-  FileData *fd = (FileData *)bh;
-  LinkNode *names = NULL;
-  BHead *bhead;
-  int tot = 0;
-
-  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
-    if (bhead->code == ofblocktype) {
-      const char *idname = blo_bhead_id_name(fd, bhead);
-      if (use_assets_only && blo_bhead_id_asset_data_address(fd, bhead) == NULL) {
-        continue;
-      }
-
-      BLI_linklist_prepend(&names, BLI_strdup(idname + 2));
-      tot++;
-    }
-    else if (bhead->code == ENDB) {
-      break;
-    }
-  }
-
-  *r_tot_names = tot;
-  return names;
-}
-
-LinkNode *BLO_blendhandle_get_datablock_info(BlendHandle *bh,
-                                             int ofblocktype,
-                                             const bool use_assets_only,
-                                             int *r_tot_info_items)
-{
-  FileData *fd = (FileData *)bh;
-  LinkNode *infos = NULL;
-  BHead *bhead;
-  int tot = 0;
-
-  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
-    if (bhead->code == ENDB) {
-      break;
-    }
-    if (bhead->code == ofblocktype) {
-      const char *name = blo_bhead_id_name(fd, bhead) + 2;
-      AssetMetaData *asset_meta_data = blo_bhead_id_asset_data_address(fd, bhead);
-
-      const bool is_asset = asset_meta_data != NULL;
-      const bool skip_datablock = use_assets_only && !is_asset;
-      if (skip_datablock) {
-        continue;
-      }
-      struct BLODataBlockInfo *info = MEM_mallocN(sizeof(*info), __func__);
-
-      /* Lastly, read asset data from the following blocks. */
-      if (asset_meta_data) {
-        bhead = blo_read_asset_data_block(fd, bhead, &asset_meta_data);
-        /* blo_read_asset_data_block() reads all DATA heads and already advances bhead to the
-         * next non-DATA one. Go back, so the loop doesn't skip the non-DATA head. */
-        bhead = blo_bhead_prev(fd, bhead);
-      }
-
-      STRNCPY(info->name, name);
-      info->asset_data = asset_meta_data;
-
-      BLI_linklist_prepend(&infos, info);
-      tot++;
-    }
-  }
-
-  *r_tot_info_items = tot;
-  return infos;
-}
-
-/**
- * Read the preview rects and store in `result`.
- *
- * `bhead` should point to the block that sourced the `preview_from_file`
- *     parameter.
- * `bhead` parameter is consumed. The correct bhead pointing to the next bhead in the file after
- * the preview rects is returned by this function.
- * \param fd: The filedata to read the data from.
- * \param bhead: should point to the block that sourced the `preview_from_file parameter`.
- *               bhead is consumed. the new bhead is returned by this function.
- * \param result: the Preview Image where the preview rect will be stored.
- * \param preview_from_file: The read PreviewImage where the bhead points to. The rects of this
- * \return PreviewImage or NULL when no preview Images have been found. Caller owns the returned
- */
-static BHead *blo_blendhandle_read_preview_rects(FileData *fd,
-                                                 BHead *bhead,
-                                                 PreviewImage *result,
-                                                 const PreviewImage *preview_from_file)
-{
-  for (int preview_index = 0; preview_index < NUM_ICON_SIZES; preview_index++) {
-    if (preview_from_file->rect[preview_index] && preview_from_file->w[preview_index] &&
-        preview_from_file->h[preview_index]) {
-      bhead = blo_bhead_next(fd, bhead);
-      BLI_assert((preview_from_file->w[preview_index] * preview_from_file->h[preview_index] *
-                  sizeof(uint)) == bhead->len);
-      result->rect[preview_index] = BLO_library_read_struct(fd, bhead, "PreviewImage Icon Rect");
-    }
-    else {
-      /* This should not be needed, but can happen in 'broken' .blend files,
-       * better handle this gracefully than crashing. */
-      BLI_assert(preview_from_file->rect[preview_index] == NULL &&
-                 preview_from_file->w[preview_index] == 0 &&
-                 preview_from_file->h[preview_index] == 0);
-      result->rect[preview_index] = NULL;
-      result->w[preview_index] = result->h[preview_index] = 0;
-    }
-    BKE_previewimg_finish(result, preview_index);
-  }
-
-  return bhead;
-}
-
-PreviewImage *BLO_blendhandle_get_preview_for_id(BlendHandle *bh,
-                                                 int ofblocktype,
-                                                 const char *name)
-{
-  FileData *fd = (FileData *)bh;
-  bool looking = false;
-  const int sdna_preview_image = DNA_struct_find_nr(fd->filesdna, "PreviewImage");
-
-  for (BHead *bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
-    if (bhead->code == DATA) {
-      if (looking && bhead->SDNAnr == sdna_preview_image) {
-        PreviewImage *preview_from_file = BLO_library_read_struct(fd, bhead, "PreviewImage");
-
-        if (preview_from_file == NULL) {
-          break;
-        }
-
-        PreviewImage *result = MEM_dupallocN(preview_from_file);
-        bhead = blo_blendhandle_read_preview_rects(fd, bhead, result, preview_from_file);
-        MEM_freeN(preview_from_file);
-        return result;
-      }
-    }
-    else if (looking || bhead->code == ENDB) {
-      /* We were looking for a preview image, but didn't find any belonging to block. So it doesn't
-       * exist. */
-      break;
-    }
-    else if (bhead->code == ofblocktype) {
-      const char *idname = blo_bhead_id_name(fd, bhead);
-      if (STREQ(&idname[2], name)) {
-        looking = true;
-      }
-    }
-  }
-
-  return NULL;
-}
-
-LinkNode *BLO_blendhandle_get_previews(BlendHandle *bh, int ofblocktype, int *r_tot_prev)
-{
-  FileData *fd = (FileData *)bh;
-  LinkNode *previews = NULL;
-  BHead *bhead;
-  int looking = 0;
-  PreviewImage *prv = NULL;
-  PreviewImage *new_prv = NULL;
-  int tot = 0;
-
-  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
-    if (bhead->code == ofblocktype) {
-      const char *idname = blo_bhead_id_name(fd, bhead);
-      switch (GS(idname)) {
-        case ID_MA:  /* fall through */
-        case ID_TE:  /* fall through */
-        case ID_IM:  /* fall through */
-        case ID_WO:  /* fall through */
-        case ID_LA:  /* fall through */
-        case ID_OB:  /* fall through */
-        case ID_GR:  /* fall through */
-        case ID_SCE: /* fall through */
-        case ID_AC:  /* fall through */
-        case ID_NT:  /* fall through */
-          new_prv = MEM_callocN(sizeof(PreviewImage), "newpreview");
-          BLI_linklist_prepend(&previews, new_prv);
-          tot++;
-          looking = 1;
-          break;
-        default:
-          break;
-      }
-    }
-    else if (bhead->code == DATA) {
-      if (looking) {
-        if (bhead->SDNAnr == DNA_struct_find_nr(fd->filesdna, "PreviewImage")) {
-          prv = BLO_library_read_struct(fd, bhead, "PreviewImage");
-
-          if (prv) {
-            memcpy(new_prv, prv, sizeof(PreviewImage));
-            bhead = blo_blendhandle_read_preview_rects(fd, bhead, new_prv, prv);
-            MEM_freeN(prv);
-          }
-        }
-      }
-    }
-    else if (bhead->code == ENDB) {
-      break;
-    }
-    else {
-      looking = 0;
-      new_prv = NULL;
-      prv = NULL;
-    }
-  }
-
-  *r_tot_prev = tot;
-  return previews;
-}
-
-LinkNode *BLO_blendhandle_get_linkable_groups(BlendHandle *bh)
-{
-  FileData *fd = (FileData *)bh;
-  GSet *gathered = BLI_gset_ptr_new("linkable_groups gh");
-  LinkNode *names = NULL;
-  BHead *bhead;
-
-  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
-    if (bhead->code == ENDB) {
-      break;
-    }
-    if (BKE_idtype_idcode_is_valid(bhead->code)) {
-      if (BKE_idtype_idcode_is_linkable(bhead->code)) {
-        const char *str = BKE_idtype_idcode_to_name(bhead->code);
-
-        if (BLI_gset_add(gathered, (void *)str)) {
-          BLI_linklist_prepend(&names, BLI_strdup(str));
-        }
-      }
-    }
-  }
-
-  BLI_gset_free(gathered, NULL);
-
-  return names;
-}
-
-void BLO_blendhandle_close(BlendHandle *bh)
-{
-  FileData *fd = (FileData *)bh;
-
-  blo_filedata_free(fd);
-}
-
-/**********/
-
-BlendFileData *BLO_read_from_file(const char *filepath,
-                                  eBLOReadSkip skip_flags,
-                                  BlendFileReadReport *reports)
-{
-  BlendFileData *bfd = NULL;
-  FileData *fd;
-
-  fd = blo_filedata_from_file(filepath, reports);
-  if (fd) {
-    fd->skip_flags = skip_flags;
-    bfd = blo_read_file_internal(fd, filepath);
-    blo_filedata_free(fd);
-  }
-
-  return bfd;
-}
-
-BlendFileData *BLO_read_from_memory(const void *mem,
-                                    int memsize,
-                                    eBLOReadSkip skip_flags,
-                                    ReportList *reports)
-{
-  BlendFileData *bfd = NULL;
-  FileData *fd;
-  BlendFileReadReport bf_reports = {.reports = reports};
-
-  fd = blo_filedata_from_memory(mem, memsize, &bf_reports);
-  if (fd) {
-    fd->skip_flags = skip_flags;
-    bfd = blo_read_file_internal(fd, "");
-    blo_filedata_free(fd);
-  }
-
-  return bfd;
-}
-
-BlendFileData *BLO_read_from_memfile(Main *oldmain,
-                                     const char *filepath,
-                                     MemFile *memfile,
-                                     const struct BlendFileReadParams *params,
-                                     ReportList *reports)
-{
-  BlendFileData *bfd = NULL;
-  FileData *fd;
-  ListBase old_mainlist;
-  BlendFileReadReport bf_reports = {.reports = reports};
-
-  fd = blo_filedata_from_memfile(memfile, params, &bf_reports);
-  if (fd) {
-    fd->skip_flags = params->skip_flags;
-    BLI_strncpy(fd->relabase, filepath, sizeof(fd->relabase));
-
-    /* separate libraries from old main */
-    blo_split_main(&old_mainlist, oldmain);
-    /* add the library pointers in oldmap lookup */
-    blo_add_library_pointer_map(&old_mainlist, fd);
-
-    if ((params->skip_flags & BLO_READ_SKIP_UNDO_OLD_MAIN) == 0) {
-      /* Build idmap of old main (we only care about local data here, so we can do that after
-       * split_main() call. */
-      blo_make_old_idmap_from_main(fd, old_mainlist.first);
-    }
-
-    /* removed packed data from this trick - it's internal data that needs saves */
-
-    /* Store all existing ID caches pointers into a mapping, to allow restoring them into newly
-     * read IDs whenever possible. */
-    blo_cache_storage_init(fd, oldmain);
-
-    bfd = blo_read_file_internal(fd, filepath);
-
-    /* Ensure relinked caches are not freed together with their old IDs. */
-    blo_cache_storage_old_bmain_clear(fd, oldmain);
-
-    /* Still in-use libraries have already been moved from oldmain to new mainlist,
-     * but oldmain itself shall *never* be 'transferred' to new mainlist! */
-    BLI_assert(old_mainlist.first == oldmain);
-
-    /* That way, libs (aka mains) we did not reuse in new undone/redone state
-     * will be cleared together with oldmain... */
-    blo_join_main(&old_mainlist);
-
-    blo_filedata_free(fd);
-  }
-
-  return bfd;
-}
-
-void BLO_blendfiledata_free(BlendFileData *bfd)
-{
-  if (bfd->main) {
-    BKE_main_free(bfd->main);
-  }
-
-  if (bfd->user) {
-    MEM_freeN(bfd->user);
-  }
-
-  MEM_freeN(bfd);
-}
diff --git a/source/blender/blenloader/intern/readblenentry.cc b/source/blender/blenloader/intern/readblenentry.cc
new file mode 100644
index 00000000000..e3d6864b962
--- /dev/null
+++ b/source/blender/blenloader/intern/readblenentry.cc
@@ -0,0 +1,458 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright 2001-2002 NaN Holding BV. All rights reserved. */
+
+/** \file
+ * \ingroup blenloader
+ * `.blend` file reading entry point.
+ */
+
+#include 
+
+#include 
+#include 
+#include 
+#include 
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_ghash.h"
+#include "BLI_linklist.h"
+#include "BLI_listbase.h"
+#include "BLI_string.h"
+#include "BLI_utildefines.h"
+
+#include "DNA_genfile.h"
+#include "DNA_sdna_types.h"
+
+#include "BKE_icons.h"
+#include "BKE_idtype.h"
+#include "BKE_main.h"
+
+#include "BLO_blend_defs.h"
+#include "BLO_readfile.h"
+#include "BLO_undofile.h"
+
+#include "readfile.h"
+
+#include "BLI_sys_types.h" /* Needed for `intptr_t`. */
+
+#ifdef WIN32
+#  include "BLI_winstuff.h"
+#endif
+
+/* local prototypes --------------------- */
+void BLO_blendhandle_print_sizes(BlendHandle *bh, void *fp);
+
+/* Access routines used by filesel. */
+
+BlendHandle *BLO_blendhandle_from_file(const char *filepath, BlendFileReadReport *reports)
+{
+  BlendHandle *bh;
+
+  bh = (BlendHandle *)blo_filedata_from_file(filepath, reports);
+
+  return bh;
+}
+
+BlendHandle *BLO_blendhandle_from_memory(const void *mem,
+                                         int memsize,
+                                         BlendFileReadReport *reports)
+{
+  BlendHandle *bh;
+
+  bh = (BlendHandle *)blo_filedata_from_memory(mem, memsize, reports);
+
+  return bh;
+}
+
+void BLO_blendhandle_print_sizes(BlendHandle *bh, void *fp)
+{
+  FileData *fd = (FileData *)bh;
+  BHead *bhead;
+
+  fprintf(static_cast(fp), "[\n");
+  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
+    if (bhead->code == ENDB) {
+      break;
+    }
+
+    const SDNA_Struct *struct_info = fd->filesdna->structs[bhead->SDNAnr];
+    const char *name = fd->filesdna->types[struct_info->type];
+    char buf[4];
+
+    buf[0] = (bhead->code >> 24) & 0xFF;
+    buf[1] = (bhead->code >> 16) & 0xFF;
+    buf[2] = (bhead->code >> 8) & 0xFF;
+    buf[3] = (bhead->code >> 0) & 0xFF;
+
+    buf[0] = buf[0] ? buf[0] : ' ';
+    buf[1] = buf[1] ? buf[1] : ' ';
+    buf[2] = buf[2] ? buf[2] : ' ';
+    buf[3] = buf[3] ? buf[3] : ' ';
+
+    fprintf(static_cast(fp),
+            "['%.4s', '%s', %d, %ld ],\n",
+            buf,
+            name,
+            bhead->nr,
+            (long int)(bhead->len + sizeof(BHead)));
+  }
+  fprintf(static_cast(fp), "]\n");
+}
+
+LinkNode *BLO_blendhandle_get_datablock_names(BlendHandle *bh,
+                                              int ofblocktype,
+                                              const bool use_assets_only,
+                                              int *r_tot_names)
+{
+  FileData *fd = (FileData *)bh;
+  LinkNode *names = NULL;
+  BHead *bhead;
+  int tot = 0;
+
+  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
+    if (bhead->code == ofblocktype) {
+      const char *idname = blo_bhead_id_name(fd, bhead);
+      if (use_assets_only && blo_bhead_id_asset_data_address(fd, bhead) == NULL) {
+        continue;
+      }
+
+      BLI_linklist_prepend(&names, BLI_strdup(idname + 2));
+      tot++;
+    }
+    else if (bhead->code == ENDB) {
+      break;
+    }
+  }
+
+  *r_tot_names = tot;
+  return names;
+}
+
+LinkNode *BLO_blendhandle_get_datablock_info(BlendHandle *bh,
+                                             int ofblocktype,
+                                             const bool use_assets_only,
+                                             int *r_tot_info_items)
+{
+  FileData *fd = (FileData *)bh;
+  LinkNode *infos = NULL;
+  BHead *bhead;
+  int tot = 0;
+
+  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
+    if (bhead->code == ENDB) {
+      break;
+    }
+    if (bhead->code == ofblocktype) {
+      const char *name = blo_bhead_id_name(fd, bhead) + 2;
+      AssetMetaData *asset_meta_data = blo_bhead_id_asset_data_address(fd, bhead);
+
+      const bool is_asset = asset_meta_data != NULL;
+      const bool skip_datablock = use_assets_only && !is_asset;
+      if (skip_datablock) {
+        continue;
+      }
+      struct BLODataBlockInfo *info = static_cast(
+          MEM_mallocN(sizeof(*info), __func__));
+
+      /* Lastly, read asset data from the following blocks. */
+      if (asset_meta_data) {
+        bhead = blo_read_asset_data_block(fd, bhead, &asset_meta_data);
+        /* blo_read_asset_data_block() reads all DATA heads and already advances bhead to the
+         * next non-DATA one. Go back, so the loop doesn't skip the non-DATA head. */
+        bhead = blo_bhead_prev(fd, bhead);
+      }
+
+      STRNCPY(info->name, name);
+      info->asset_data = asset_meta_data;
+
+      BLI_linklist_prepend(&infos, info);
+      tot++;
+    }
+  }
+
+  *r_tot_info_items = tot;
+  return infos;
+}
+
+/**
+ * Read the preview rects and store in `result`.
+ *
+ * `bhead` should point to the block that sourced the `preview_from_file`
+ *     parameter.
+ * `bhead` parameter is consumed. The correct bhead pointing to the next bhead in the file after
+ * the preview rects is returned by this function.
+ * \param fd: The filedata to read the data from.
+ * \param bhead: should point to the block that sourced the `preview_from_file parameter`.
+ *               bhead is consumed. the new bhead is returned by this function.
+ * \param result: the Preview Image where the preview rect will be stored.
+ * \param preview_from_file: The read PreviewImage where the bhead points to. The rects of this
+ * \return PreviewImage or NULL when no preview Images have been found. Caller owns the returned
+ */
+static BHead *blo_blendhandle_read_preview_rects(FileData *fd,
+                                                 BHead *bhead,
+                                                 PreviewImage *result,
+                                                 const PreviewImage *preview_from_file)
+{
+  for (int preview_index = 0; preview_index < NUM_ICON_SIZES; preview_index++) {
+    if (preview_from_file->rect[preview_index] && preview_from_file->w[preview_index] &&
+        preview_from_file->h[preview_index]) {
+      bhead = blo_bhead_next(fd, bhead);
+      BLI_assert((preview_from_file->w[preview_index] * preview_from_file->h[preview_index] *
+                  sizeof(uint)) == bhead->len);
+      result->rect[preview_index] = static_cast(
+          BLO_library_read_struct(fd, bhead, "PreviewImage Icon Rect"));
+    }
+    else {
+      /* This should not be needed, but can happen in 'broken' .blend files,
+       * better handle this gracefully than crashing. */
+      BLI_assert(preview_from_file->rect[preview_index] == NULL &&
+                 preview_from_file->w[preview_index] == 0 &&
+                 preview_from_file->h[preview_index] == 0);
+      result->rect[preview_index] = NULL;
+      result->w[preview_index] = result->h[preview_index] = 0;
+    }
+    BKE_previewimg_finish(result, preview_index);
+  }
+
+  return bhead;
+}
+
+PreviewImage *BLO_blendhandle_get_preview_for_id(BlendHandle *bh,
+                                                 int ofblocktype,
+                                                 const char *name)
+{
+  FileData *fd = (FileData *)bh;
+  bool looking = false;
+  const int sdna_preview_image = DNA_struct_find_nr(fd->filesdna, "PreviewImage");
+
+  for (BHead *bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
+    if (bhead->code == DATA) {
+      if (looking && bhead->SDNAnr == sdna_preview_image) {
+        PreviewImage *preview_from_file = static_cast(
+            BLO_library_read_struct(fd, bhead, "PreviewImage"));
+
+        if (preview_from_file == NULL) {
+          break;
+        }
+
+        PreviewImage *result = static_cast(MEM_dupallocN(preview_from_file));
+        bhead = blo_blendhandle_read_preview_rects(fd, bhead, result, preview_from_file);
+        MEM_freeN(preview_from_file);
+        return result;
+      }
+    }
+    else if (looking || bhead->code == ENDB) {
+      /* We were looking for a preview image, but didn't find any belonging to block. So it doesn't
+       * exist. */
+      break;
+    }
+    else if (bhead->code == ofblocktype) {
+      const char *idname = blo_bhead_id_name(fd, bhead);
+      if (STREQ(&idname[2], name)) {
+        looking = true;
+      }
+    }
+  }
+
+  return NULL;
+}
+
+LinkNode *BLO_blendhandle_get_previews(BlendHandle *bh, int ofblocktype, int *r_tot_prev)
+{
+  FileData *fd = (FileData *)bh;
+  LinkNode *previews = NULL;
+  BHead *bhead;
+  int looking = 0;
+  PreviewImage *prv = NULL;
+  PreviewImage *new_prv = NULL;
+  int tot = 0;
+
+  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
+    if (bhead->code == ofblocktype) {
+      const char *idname = blo_bhead_id_name(fd, bhead);
+      switch (GS(idname)) {
+        case ID_MA:  /* fall through */
+        case ID_TE:  /* fall through */
+        case ID_IM:  /* fall through */
+        case ID_WO:  /* fall through */
+        case ID_LA:  /* fall through */
+        case ID_OB:  /* fall through */
+        case ID_GR:  /* fall through */
+        case ID_SCE: /* fall through */
+        case ID_AC:  /* fall through */
+        case ID_NT:  /* fall through */
+          new_prv = static_cast(MEM_callocN(sizeof(PreviewImage), "newpreview"));
+          BLI_linklist_prepend(&previews, new_prv);
+          tot++;
+          looking = 1;
+          break;
+        default:
+          break;
+      }
+    }
+    else if (bhead->code == DATA) {
+      if (looking) {
+        if (bhead->SDNAnr == DNA_struct_find_nr(fd->filesdna, "PreviewImage")) {
+          prv = static_cast(BLO_library_read_struct(fd, bhead, "PreviewImage"));
+
+          if (prv) {
+            memcpy(new_prv, prv, sizeof(PreviewImage));
+            bhead = blo_blendhandle_read_preview_rects(fd, bhead, new_prv, prv);
+            MEM_freeN(prv);
+          }
+        }
+      }
+    }
+    else if (bhead->code == ENDB) {
+      break;
+    }
+    else {
+      looking = 0;
+      new_prv = NULL;
+      prv = NULL;
+    }
+  }
+
+  *r_tot_prev = tot;
+  return previews;
+}
+
+LinkNode *BLO_blendhandle_get_linkable_groups(BlendHandle *bh)
+{
+  FileData *fd = (FileData *)bh;
+  GSet *gathered = BLI_gset_ptr_new("linkable_groups gh");
+  LinkNode *names = NULL;
+  BHead *bhead;
+
+  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
+    if (bhead->code == ENDB) {
+      break;
+    }
+    if (BKE_idtype_idcode_is_valid(bhead->code)) {
+      if (BKE_idtype_idcode_is_linkable(bhead->code)) {
+        const char *str = BKE_idtype_idcode_to_name(bhead->code);
+
+        if (BLI_gset_add(gathered, (void *)str)) {
+          BLI_linklist_prepend(&names, BLI_strdup(str));
+        }
+      }
+    }
+  }
+
+  BLI_gset_free(gathered, NULL);
+
+  return names;
+}
+
+void BLO_blendhandle_close(BlendHandle *bh)
+{
+  FileData *fd = (FileData *)bh;
+
+  blo_filedata_free(fd);
+}
+
+/**********/
+
+BlendFileData *BLO_read_from_file(const char *filepath,
+                                  eBLOReadSkip skip_flags,
+                                  BlendFileReadReport *reports)
+{
+  BlendFileData *bfd = NULL;
+  FileData *fd;
+
+  fd = blo_filedata_from_file(filepath, reports);
+  if (fd) {
+    fd->skip_flags = skip_flags;
+    bfd = blo_read_file_internal(fd, filepath);
+    blo_filedata_free(fd);
+  }
+
+  return bfd;
+}
+
+BlendFileData *BLO_read_from_memory(const void *mem,
+                                    int memsize,
+                                    eBLOReadSkip skip_flags,
+                                    ReportList *reports)
+{
+  BlendFileData *bfd = NULL;
+  FileData *fd;
+  BlendFileReadReport bf_reports{};
+  bf_reports.reports = reports;
+
+  fd = blo_filedata_from_memory(mem, memsize, &bf_reports);
+  if (fd) {
+    fd->skip_flags = skip_flags;
+    bfd = blo_read_file_internal(fd, "");
+    blo_filedata_free(fd);
+  }
+
+  return bfd;
+}
+
+BlendFileData *BLO_read_from_memfile(Main *oldmain,
+                                     const char *filepath,
+                                     MemFile *memfile,
+                                     const struct BlendFileReadParams *params,
+                                     ReportList *reports)
+{
+  BlendFileData *bfd = NULL;
+  FileData *fd;
+  ListBase old_mainlist;
+  BlendFileReadReport bf_reports{};
+  bf_reports.reports = reports;
+
+  fd = blo_filedata_from_memfile(memfile, params, &bf_reports);
+  if (fd) {
+    fd->skip_flags = eBLOReadSkip(params->skip_flags);
+    BLI_strncpy(fd->relabase, filepath, sizeof(fd->relabase));
+
+    /* separate libraries from old main */
+    blo_split_main(&old_mainlist, oldmain);
+    /* add the library pointers in oldmap lookup */
+    blo_add_library_pointer_map(&old_mainlist, fd);
+
+    if ((params->skip_flags & BLO_READ_SKIP_UNDO_OLD_MAIN) == 0) {
+      /* Build idmap of old main (we only care about local data here, so we can do that after
+       * split_main() call. */
+      blo_make_old_idmap_from_main(fd, static_cast
(old_mainlist.first));
+    }
+
+    /* removed packed data from this trick - it's internal data that needs saves */
+
+    /* Store all existing ID caches pointers into a mapping, to allow restoring them into newly
+     * read IDs whenever possible. */
+    blo_cache_storage_init(fd, oldmain);
+
+    bfd = blo_read_file_internal(fd, filepath);
+
+    /* Ensure relinked caches are not freed together with their old IDs. */
+    blo_cache_storage_old_bmain_clear(fd, oldmain);
+
+    /* Still in-use libraries have already been moved from oldmain to new mainlist,
+     * but oldmain itself shall *never* be 'transferred' to new mainlist! */
+    BLI_assert(old_mainlist.first == oldmain);
+
+    /* That way, libs (aka mains) we did not reuse in new undone/redone state
+     * will be cleared together with oldmain... */
+    blo_join_main(&old_mainlist);
+
+    blo_filedata_free(fd);
+  }
+
+  return bfd;
+}
+
+void BLO_blendfiledata_free(BlendFileData *bfd)
+{
+  if (bfd->main) {
+    BKE_main_free(bfd->main);
+  }
+
+  if (bfd->user) {
+    MEM_freeN(bfd->user);
+  }
+
+  MEM_freeN(bfd);
+}
diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
deleted file mode 100644
index f0d390677bb..00000000000
--- a/source/blender/blenloader/intern/readfile.c
+++ /dev/null
@@ -1,5152 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later
- * Copyright 2001-2002 NaN Holding BV. All rights reserved. */
-
-/** \file
- * \ingroup blenloader
- */
-
-#include  /* for isdigit. */
-#include  /* for open flags (O_BINARY, O_RDONLY). */
-#include 
-#include  /* for va_start/end. */
-#include  /* for offsetof. */
-#include  /* for atoi. */
-#include    /* for gmtime. */
-
-#include "BLI_utildefines.h"
-#ifndef WIN32
-#  include  /* for read close */
-#else
-#  include "BLI_winstuff.h"
-#  include "winsock2.h"
-#  include  /* for open close read */
-#endif
-
-#include "CLG_log.h"
-
-/* allow readfile to use deprecated functionality */
-#define DNA_DEPRECATED_ALLOW
-
-#include "DNA_anim_types.h"
-#include "DNA_asset_types.h"
-#include "DNA_cachefile_types.h"
-#include "DNA_collection_types.h"
-#include "DNA_fileglobal_types.h"
-#include "DNA_genfile.h"
-#include "DNA_key_types.h"
-#include "DNA_layer_types.h"
-#include "DNA_node_types.h"
-#include "DNA_packedFile_types.h"
-#include "DNA_sdna_types.h"
-#include "DNA_sound_types.h"
-#include "DNA_vfont_types.h"
-#include "DNA_volume_types.h"
-#include "DNA_workspace_types.h"
-
-#include "MEM_guardedalloc.h"
-
-#include "BLI_blenlib.h"
-#include "BLI_endian_defines.h"
-#include "BLI_endian_switch.h"
-#include "BLI_ghash.h"
-#include "BLI_linklist.h"
-#include "BLI_math.h"
-#include "BLI_memarena.h"
-#include "BLI_mempool.h"
-#include "BLI_threads.h"
-
-#include "PIL_time.h"
-
-#include "BLT_translation.h"
-
-#include "BKE_anim_data.h"
-#include "BKE_animsys.h"
-#include "BKE_asset.h"
-#include "BKE_collection.h"
-#include "BKE_global.h" /* for G */
-#include "BKE_idprop.h"
-#include "BKE_idtype.h"
-#include "BKE_layer.h"
-#include "BKE_lib_id.h"
-#include "BKE_lib_override.h"
-#include "BKE_lib_query.h"
-#include "BKE_main.h" /* for Main */
-#include "BKE_main_idmap.h"
-#include "BKE_material.h"
-#include "BKE_modifier.h"
-#include "BKE_node.h" /* for tree type defines */
-#include "BKE_object.h"
-#include "BKE_packedFile.h"
-#include "BKE_report.h"
-#include "BKE_scene.h"
-#include "BKE_screen.h"
-#include "BKE_undo_system.h"
-#include "BKE_workspace.h"
-
-#include "DRW_engine.h"
-
-#include "DEG_depsgraph.h"
-
-#include "BLO_blend_defs.h"
-#include "BLO_blend_validate.h"
-#include "BLO_read_write.h"
-#include "BLO_readfile.h"
-#include "BLO_undofile.h"
-
-#include "SEQ_clipboard.h"
-#include "SEQ_iterator.h"
-#include "SEQ_modifier.h"
-#include "SEQ_sequencer.h"
-#include "SEQ_utils.h"
-
-#include "readfile.h"
-
-#include 
-
-/* Make preferences read-only. */
-#define U (*((const UserDef *)&U))
-
-/**
- * READ
- * ====
- *
- * - Existing Library (#Main) push or free
- * - allocate new #Main
- * - load file
- * - read #SDNA
- * - for each LibBlock
- *   - read LibBlock
- *   - if a Library
- *     - make a new #Main
- *     - attach ID's to it
- *   - else
- *     - read associated 'direct data'
- *     - link direct data (internal and to LibBlock)
- * - read #FileGlobal
- * - read #USER data, only when indicated (file is `~/.config/blender/X.XX/config/userpref.blend`)
- * - free file
- * - per Library (per #Main)
- *   - read file
- *   - read #SDNA
- *   - find LibBlocks and attach #ID's to #Main
- *     - if external LibBlock
- *       - search all #Main's
- *         - or it's already read,
- *         - or not read yet
- *         - or make new #Main
- *   - per LibBlock
- *     - read recursive
- *     - read associated direct data
- *     - link direct data (internal and to LibBlock)
- *   - free file
- * - per Library with unread LibBlocks
- *   - read file
- *   - read #SDNA
- *   - per LibBlock
- *     - read recursive
- *     - read associated direct data
- *     - link direct data (internal and to LibBlock)
- *   - free file
- * - join all #Main's
- * - link all LibBlocks and indirect pointers to libblocks
- * - initialize #FileGlobal and copy pointers to #Global
- *
- * \note Still a weak point is the new-address function, that doesn't solve reading from
- * multiple files at the same time.
- * (added remark: oh, i thought that was solved? will look at that... (ton).
- */
-
-/**
- * Delay reading blocks we might not use (especially applies to library linking).
- * which keeps large arrays in memory from data-blocks we may not even use.
- *
- * \note This is disabled when using compression,
- * while ZLIB supports seek it's unusably slow, see: T61880.
- */
-#define USE_BHEAD_READ_ON_DEMAND
-
-/** Use #GHash for #BHead name-based lookups (speeds up linking). */
-#define USE_GHASH_BHEAD
-
-/** Use #GHash for restoring pointers by name. */
-#define USE_GHASH_RESTORE_POINTER
-
-static CLG_LogRef LOG = {"blo.readfile"};
-static CLG_LogRef LOG_UNDO = {"blo.readfile.undo"};
-
-/* local prototypes */
-static void read_libraries(FileData *basefd, ListBase *mainlist);
-static void *read_struct(FileData *fd, BHead *bh, const char *blockname);
-static BHead *find_bhead_from_code_name(FileData *fd, const short idcode, const char *name);
-static BHead *find_bhead_from_idname(FileData *fd, const char *idname);
-
-typedef struct BHeadN {
-  struct BHeadN *next, *prev;
-#ifdef USE_BHEAD_READ_ON_DEMAND
-  /** Use to read the data from the file directly into memory as needed. */
-  off64_t file_offset;
-  /** When set, the remainder of this allocation is the data, otherwise it needs to be read. */
-  bool has_data;
-#endif
-  bool is_memchunk_identical;
-  struct BHead bhead;
-} BHeadN;
-
-#define BHEADN_FROM_BHEAD(bh) ((BHeadN *)POINTER_OFFSET(bh, -(int)offsetof(BHeadN, bhead)))
-
-/**
- * We could change this in the future, for now it's simplest if only data is delayed
- * because ID names are used in lookup tables.
- */
-#define BHEAD_USE_READ_ON_DEMAND(bhead) ((bhead)->code == DATA)
-
-void BLO_reportf_wrap(BlendFileReadReport *reports, eReportType type, const char *format, ...)
-{
-  char fixed_buf[1024]; /* should be long enough */
-
-  va_list args;
-
-  va_start(args, format);
-  vsnprintf(fixed_buf, sizeof(fixed_buf), format, args);
-  va_end(args);
-
-  fixed_buf[sizeof(fixed_buf) - 1] = '\0';
-
-  BKE_report(reports->reports, type, fixed_buf);
-
-  if (G.background == 0) {
-    printf("%s: %s\n", BKE_report_type_str(type), fixed_buf);
-  }
-}
-
-/* for reporting linking messages */
-static const char *library_parent_filepath(Library *lib)
-{
-  return lib->parent ? lib->parent->filepath_abs : "";
-}
-
-/* -------------------------------------------------------------------- */
-/** \name OldNewMap API
- * \{ */
-
-typedef struct OldNew {
-  const void *oldp;
-  void *newp;
-  /* `nr` is "user count" for data, and ID code for libdata. */
-  int nr;
-} OldNew;
-
-typedef struct OldNewMap {
-  /* Array that stores the actual entries. */
-  OldNew *entries;
-  int nentries;
-  /* Hash-map that stores indices into the `entries` array. */
-  int32_t *map;
-
-  int capacity_exp;
-} OldNewMap;
-
-#define ENTRIES_CAPACITY(onm) (1ll << (onm)->capacity_exp)
-#define MAP_CAPACITY(onm) (1ll << ((onm)->capacity_exp + 1))
-#define SLOT_MASK(onm) (MAP_CAPACITY(onm) - 1)
-#define DEFAULT_SIZE_EXP 6
-#define PERTURB_SHIFT 5
-
-/* based on the probing algorithm used in Python dicts. */
-#define ITER_SLOTS(onm, KEY, SLOT_NAME, INDEX_NAME) \
-  uint32_t hash = BLI_ghashutil_ptrhash(KEY); \
-  uint32_t mask = SLOT_MASK(onm); \
-  uint perturb = hash; \
-  int SLOT_NAME = mask & hash; \
-  int INDEX_NAME = onm->map[SLOT_NAME]; \
-  for (;; SLOT_NAME = mask & ((5 * SLOT_NAME) + 1 + perturb), \
-          perturb >>= PERTURB_SHIFT, \
-          INDEX_NAME = onm->map[SLOT_NAME])
-
-static void oldnewmap_insert_index_in_map(OldNewMap *onm, const void *ptr, int index)
-{
-  ITER_SLOTS (onm, ptr, slot, stored_index) {
-    if (stored_index == -1) {
-      onm->map[slot] = index;
-      break;
-    }
-  }
-}
-
-static void oldnewmap_insert_or_replace(OldNewMap *onm, OldNew entry)
-{
-  ITER_SLOTS (onm, entry.oldp, slot, index) {
-    if (index == -1) {
-      onm->entries[onm->nentries] = entry;
-      onm->map[slot] = onm->nentries;
-      onm->nentries++;
-      break;
-    }
-    if (onm->entries[index].oldp == entry.oldp) {
-      onm->entries[index] = entry;
-      break;
-    }
-  }
-}
-
-static OldNew *oldnewmap_lookup_entry(const OldNewMap *onm, const void *addr)
-{
-  ITER_SLOTS (onm, addr, slot, index) {
-    if (index >= 0) {
-      OldNew *entry = &onm->entries[index];
-      if (entry->oldp == addr) {
-        return entry;
-      }
-    }
-    else {
-      return NULL;
-    }
-  }
-}
-
-static void oldnewmap_clear_map(OldNewMap *onm)
-{
-  memset(onm->map, 0xFF, MAP_CAPACITY(onm) * sizeof(*onm->map));
-}
-
-static void oldnewmap_increase_size(OldNewMap *onm)
-{
-  onm->capacity_exp++;
-  onm->entries = MEM_reallocN(onm->entries, sizeof(*onm->entries) * ENTRIES_CAPACITY(onm));
-  onm->map = MEM_reallocN(onm->map, sizeof(*onm->map) * MAP_CAPACITY(onm));
-  oldnewmap_clear_map(onm);
-  for (int i = 0; i < onm->nentries; i++) {
-    oldnewmap_insert_index_in_map(onm, onm->entries[i].oldp, i);
-  }
-}
-
-/* Public OldNewMap API */
-
-static void oldnewmap_init_data(OldNewMap *onm, const int capacity_exp)
-{
-  memset(onm, 0x0, sizeof(*onm));
-
-  onm->capacity_exp = capacity_exp;
-  onm->entries = MEM_malloc_arrayN(
-      ENTRIES_CAPACITY(onm), sizeof(*onm->entries), "OldNewMap.entries");
-  onm->map = MEM_malloc_arrayN(MAP_CAPACITY(onm), sizeof(*onm->map), "OldNewMap.map");
-  oldnewmap_clear_map(onm);
-}
-
-static OldNewMap *oldnewmap_new(void)
-{
-  OldNewMap *onm = MEM_mallocN(sizeof(*onm), "OldNewMap");
-
-  oldnewmap_init_data(onm, DEFAULT_SIZE_EXP);
-
-  return onm;
-}
-
-static void oldnewmap_insert(OldNewMap *onm, const void *oldaddr, void *newaddr, int nr)
-{
-  if (oldaddr == NULL || newaddr == NULL) {
-    return;
-  }
-
-  if (UNLIKELY(onm->nentries == ENTRIES_CAPACITY(onm))) {
-    oldnewmap_increase_size(onm);
-  }
-
-  OldNew entry;
-  entry.oldp = oldaddr;
-  entry.newp = newaddr;
-  entry.nr = nr;
-  oldnewmap_insert_or_replace(onm, entry);
-}
-
-void blo_do_versions_oldnewmap_insert(OldNewMap *onm, const void *oldaddr, void *newaddr, int nr)
-{
-  oldnewmap_insert(onm, oldaddr, newaddr, nr);
-}
-
-static void *oldnewmap_lookup_and_inc(OldNewMap *onm, const void *addr, bool increase_users)
-{
-  OldNew *entry = oldnewmap_lookup_entry(onm, addr);
-  if (entry == NULL) {
-    return NULL;
-  }
-  if (increase_users) {
-    entry->nr++;
-  }
-  return entry->newp;
-}
-
-/* for libdata, OldNew.nr has ID code, no increment */
-static void *oldnewmap_liblookup(OldNewMap *onm, const void *addr, const void *lib)
-{
-  if (addr == NULL) {
-    return NULL;
-  }
-
-  ID *id = oldnewmap_lookup_and_inc(onm, addr, false);
-  if (id == NULL) {
-    return NULL;
-  }
-  if (!lib || id->lib) {
-    return id;
-  }
-  return NULL;
-}
-
-static void oldnewmap_clear(OldNewMap *onm)
-{
-  /* Free unused data. */
-  for (int i = 0; i < onm->nentries; i++) {
-    OldNew *entry = &onm->entries[i];
-    if (entry->nr == 0) {
-      MEM_freeN(entry->newp);
-      entry->newp = NULL;
-    }
-  }
-
-  MEM_freeN(onm->entries);
-  MEM_freeN(onm->map);
-
-  oldnewmap_init_data(onm, DEFAULT_SIZE_EXP);
-}
-
-static void oldnewmap_free(OldNewMap *onm)
-{
-  MEM_freeN(onm->entries);
-  MEM_freeN(onm->map);
-  MEM_freeN(onm);
-}
-
-#undef ENTRIES_CAPACITY
-#undef MAP_CAPACITY
-#undef SLOT_MASK
-#undef DEFAULT_SIZE_EXP
-#undef PERTURB_SHIFT
-#undef ITER_SLOTS
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Helper Functions
- * \{ */
-
-static void add_main_to_main(Main *mainvar, Main *from)
-{
-  ListBase *lbarray[INDEX_ID_MAX], *fromarray[INDEX_ID_MAX];
-  int a;
-
-  set_listbasepointers(mainvar, lbarray);
-  a = set_listbasepointers(from, fromarray);
-  while (a--) {
-    BLI_movelisttolist(lbarray[a], fromarray[a]);
-  }
-}
-
-void blo_join_main(ListBase *mainlist)
-{
-  Main *tojoin, *mainl;
-
-  mainl = mainlist->first;
-
-  if (mainl->id_map != NULL) {
-    /* Cannot keep this since we add some IDs from joined mains. */
-    BKE_main_idmap_destroy(mainl->id_map);
-    mainl->id_map = NULL;
-  }
-
-  while ((tojoin = mainl->next)) {
-    add_main_to_main(mainl, tojoin);
-    BLI_remlink(mainlist, tojoin);
-    BKE_main_free(tojoin);
-  }
-}
-
-static void split_libdata(ListBase *lb_src, Main **lib_main_array, const uint lib_main_array_len)
-{
-  for (ID *id = lb_src->first, *idnext; id; id = idnext) {
-    idnext = id->next;
-
-    if (id->lib) {
-      if (((uint)id->lib->temp_index < lib_main_array_len) &&
-          /* this check should never fail, just in case 'id->lib' is a dangling pointer. */
-          (lib_main_array[id->lib->temp_index]->curlib == id->lib)) {
-        Main *mainvar = lib_main_array[id->lib->temp_index];
-        ListBase *lb_dst = which_libbase(mainvar, GS(id->name));
-        BLI_remlink(lb_src, id);
-        BLI_addtail(lb_dst, id);
-      }
-      else {
-        CLOG_ERROR(&LOG, "Invalid library for '%s'", id->name);
-      }
-    }
-  }
-}
-
-void blo_split_main(ListBase *mainlist, Main *main)
-{
-  mainlist->first = mainlist->last = main;
-  main->next = NULL;
-
-  if (BLI_listbase_is_empty(&main->libraries)) {
-    return;
-  }
-
-  if (main->id_map != NULL) {
-    /* Cannot keep this since we remove some IDs from given main. */
-    BKE_main_idmap_destroy(main->id_map);
-    main->id_map = NULL;
-  }
-
-  /* (Library.temp_index -> Main), lookup table */
-  const uint lib_main_array_len = BLI_listbase_count(&main->libraries);
-  Main **lib_main_array = MEM_malloc_arrayN(lib_main_array_len, sizeof(*lib_main_array), __func__);
-
-  int i = 0;
-  for (Library *lib = main->libraries.first; lib; lib = lib->id.next, i++) {
-    Main *libmain = BKE_main_new();
-    libmain->curlib = lib;
-    libmain->versionfile = lib->versionfile;
-    libmain->subversionfile = lib->subversionfile;
-    BLI_addtail(mainlist, libmain);
-    lib->temp_index = i;
-    lib_main_array[i] = libmain;
-  }
-
-  ListBase *lbarray[INDEX_ID_MAX];
-  i = set_listbasepointers(main, lbarray);
-  while (i--) {
-    ID *id = lbarray[i]->first;
-    if (id == NULL || GS(id->name) == ID_LI) {
-      /* No ID_LI data-lock should ever be linked anyway, but just in case, better be explicit. */
-      continue;
-    }
-    split_libdata(lbarray[i], lib_main_array, lib_main_array_len);
-  }
-
-  MEM_freeN(lib_main_array);
-}
-
-static void read_file_version(FileData *fd, Main *main)
-{
-  BHead *bhead;
-
-  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
-    if (bhead->code == GLOB) {
-      FileGlobal *fg = read_struct(fd, bhead, "Global");
-      if (fg) {
-        main->subversionfile = fg->subversion;
-        main->minversionfile = fg->minversion;
-        main->minsubversionfile = fg->minsubversion;
-        MEM_freeN(fg);
-      }
-      else if (bhead->code == ENDB) {
-        break;
-      }
-    }
-  }
-  if (main->curlib) {
-    main->curlib->versionfile = main->versionfile;
-    main->curlib->subversionfile = main->subversionfile;
-  }
-}
-
-static bool blo_bhead_is_id(const BHead *bhead)
-{
-  /* BHead codes are four bytes (like 'ENDB', 'TEST', etc.), but if the two most-significant bytes
-   * are zero, the values actually indicate an ID type. */
-  return bhead->code <= 0xFFFF;
-}
-
-static bool blo_bhead_is_id_valid_type(const BHead *bhead)
-{
-  if (!blo_bhead_is_id(bhead)) {
-    return false;
-  }
-
-  const short id_type_code = bhead->code & 0xFFFF;
-  return BKE_idtype_idcode_is_valid(id_type_code);
-}
-
-#ifdef USE_GHASH_BHEAD
-static void read_file_bhead_idname_map_create(FileData *fd)
-{
-  BHead *bhead;
-
-  /* dummy values */
-  bool is_link = false;
-  int code_prev = ENDB;
-  uint reserve = 0;
-
-  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
-    if (code_prev != bhead->code) {
-      code_prev = bhead->code;
-      is_link = blo_bhead_is_id_valid_type(bhead) ?
-                    BKE_idtype_idcode_is_linkable((short)code_prev) :
-                    false;
-    }
-
-    if (is_link) {
-      reserve += 1;
-    }
-  }
-
-  BLI_assert(fd->bhead_idname_hash == NULL);
-
-  fd->bhead_idname_hash = BLI_ghash_str_new_ex(__func__, reserve);
-
-  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
-    if (code_prev != bhead->code) {
-      code_prev = bhead->code;
-      is_link = blo_bhead_is_id_valid_type(bhead) ?
-                    BKE_idtype_idcode_is_linkable((short)code_prev) :
-                    false;
-    }
-
-    if (is_link) {
-      BLI_ghash_insert(fd->bhead_idname_hash, (void *)blo_bhead_id_name(fd, bhead), bhead);
-    }
-  }
-}
-#endif
-
-static Main *blo_find_main(FileData *fd, const char *filepath, const char *relabase)
-{
-  ListBase *mainlist = fd->mainlist;
-  Main *m;
-  Library *lib;
-  char name1[FILE_MAX];
-
-  BLI_strncpy(name1, filepath, sizeof(name1));
-  BLI_path_normalize(relabase, name1);
-
-  //  printf("blo_find_main: relabase  %s\n", relabase);
-  //  printf("blo_find_main: original in  %s\n", filepath);
-  //  printf("blo_find_main: converted to %s\n", name1);
-
-  for (m = mainlist->first; m; m = m->next) {
-    const char *libname = (m->curlib) ? m->curlib->filepath_abs : m->filepath;
-
-    if (BLI_path_cmp(name1, libname) == 0) {
-      if (G.debug & G_DEBUG) {
-        CLOG_INFO(&LOG, 3, "Found library %s", libname);
-      }
-      return m;
-    }
-  }
-
-  m = BKE_main_new();
-  BLI_addtail(mainlist, m);
-
-  /* Add library data-block itself to 'main' Main, since libraries are **never** linked data.
-   * Fixes bug where you could end with all ID_LI data-blocks having the same name... */
-  lib = BKE_libblock_alloc(mainlist->first, ID_LI, BLI_path_basename(filepath), 0);
-
-  /* Important, consistency with main ID reading code from read_libblock(). */
-  lib->id.us = ID_FAKE_USERS(lib);
-
-  /* Matches direct_link_library(). */
-  id_us_ensure_real(&lib->id);
-
-  BLI_strncpy(lib->filepath, filepath, sizeof(lib->filepath));
-  BLI_strncpy(lib->filepath_abs, name1, sizeof(lib->filepath_abs));
-
-  m->curlib = lib;
-
-  read_file_version(fd, m);
-
-  if (G.debug & G_DEBUG) {
-    CLOG_INFO(&LOG, 3, "Added new lib %s", filepath);
-  }
-  return m;
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name File Parsing
- * \{ */
-
-typedef struct BlendDataReader {
-  FileData *fd;
-} BlendDataReader;
-
-typedef struct BlendLibReader {
-  FileData *fd;
-  Main *main;
-} BlendLibReader;
-
-typedef struct BlendExpander {
-  FileData *fd;
-  Main *main;
-} BlendExpander;
-
-static void switch_endian_bh4(BHead4 *bhead)
-{
-  /* the ID_.. codes */
-  if ((bhead->code & 0xFFFF) == 0) {
-    bhead->code >>= 16;
-  }
-
-  if (bhead->code != ENDB) {
-    BLI_endian_switch_int32(&bhead->len);
-    BLI_endian_switch_int32(&bhead->SDNAnr);
-    BLI_endian_switch_int32(&bhead->nr);
-  }
-}
-
-static void switch_endian_bh8(BHead8 *bhead)
-{
-  /* the ID_.. codes */
-  if ((bhead->code & 0xFFFF) == 0) {
-    bhead->code >>= 16;
-  }
-
-  if (bhead->code != ENDB) {
-    BLI_endian_switch_int32(&bhead->len);
-    BLI_endian_switch_int32(&bhead->SDNAnr);
-    BLI_endian_switch_int32(&bhead->nr);
-  }
-}
-
-static void bh4_from_bh8(BHead *bhead, BHead8 *bhead8, bool do_endian_swap)
-{
-  BHead4 *bhead4 = (BHead4 *)bhead;
-  int64_t old;
-
-  bhead4->code = bhead8->code;
-  bhead4->len = bhead8->len;
-
-  if (bhead4->code != ENDB) {
-    /* perform a endian swap on 64bit pointers, otherwise the pointer might map to zero
-     * 0x0000000000000000000012345678 would become 0x12345678000000000000000000000000
-     */
-    if (do_endian_swap) {
-      BLI_endian_switch_uint64(&bhead8->old);
-    }
-
-    /* this patch is to avoid `intptr_t` being read from not-eight aligned positions
-     * is necessary on any modern 64bit architecture) */
-    memcpy(&old, &bhead8->old, 8);
-    bhead4->old = (int)(old >> 3);
-
-    bhead4->SDNAnr = bhead8->SDNAnr;
-    bhead4->nr = bhead8->nr;
-  }
-}
-
-static void bh8_from_bh4(BHead *bhead, BHead4 *bhead4)
-{
-  BHead8 *bhead8 = (BHead8 *)bhead;
-
-  bhead8->code = bhead4->code;
-  bhead8->len = bhead4->len;
-
-  if (bhead8->code != ENDB) {
-    bhead8->old = bhead4->old;
-    bhead8->SDNAnr = bhead4->SDNAnr;
-    bhead8->nr = bhead4->nr;
-  }
-}
-
-static BHeadN *get_bhead(FileData *fd)
-{
-  BHeadN *new_bhead = NULL;
-  ssize_t readsize;
-
-  if (fd) {
-    if (!fd->is_eof) {
-      /* initializing to zero isn't strictly needed but shuts valgrind up
-       * since uninitialized memory gets compared */
-      BHead8 bhead8 = {0};
-      BHead4 bhead4 = {0};
-      BHead bhead = {0};
-
-      /* First read the bhead structure.
-       * Depending on the platform the file was written on this can
-       * be a big or little endian BHead4 or BHead8 structure.
-       *
-       * As usual 'ENDB' (the last *partial* bhead of the file)
-       * needs some special handling. We don't want to EOF just yet.
-       */
-      if (fd->flags & FD_FLAGS_FILE_POINTSIZE_IS_4) {
-        bhead4.code = DATA;
-        readsize = fd->file->read(fd->file, &bhead4, sizeof(bhead4));
-
-        if (readsize == sizeof(bhead4) || bhead4.code == ENDB) {
-          if (fd->flags & FD_FLAGS_SWITCH_ENDIAN) {
-            switch_endian_bh4(&bhead4);
-          }
-
-          if (fd->flags & FD_FLAGS_POINTSIZE_DIFFERS) {
-            bh8_from_bh4(&bhead, &bhead4);
-          }
-          else {
-            /* MIN2 is only to quiet '-Warray-bounds' compiler warning. */
-            BLI_assert(sizeof(bhead) == sizeof(bhead4));
-            memcpy(&bhead, &bhead4, MIN2(sizeof(bhead), sizeof(bhead4)));
-          }
-        }
-        else {
-          fd->is_eof = true;
-          bhead.len = 0;
-        }
-      }
-      else {
-        bhead8.code = DATA;
-        readsize = fd->file->read(fd->file, &bhead8, sizeof(bhead8));
-
-        if (readsize == sizeof(bhead8) || bhead8.code == ENDB) {
-          if (fd->flags & FD_FLAGS_SWITCH_ENDIAN) {
-            switch_endian_bh8(&bhead8);
-          }
-
-          if (fd->flags & FD_FLAGS_POINTSIZE_DIFFERS) {
-            bh4_from_bh8(&bhead, &bhead8, (fd->flags & FD_FLAGS_SWITCH_ENDIAN) != 0);
-          }
-          else {
-            /* MIN2 is only to quiet '-Warray-bounds' compiler warning. */
-            BLI_assert(sizeof(bhead) == sizeof(bhead8));
-            memcpy(&bhead, &bhead8, MIN2(sizeof(bhead), sizeof(bhead8)));
-          }
-        }
-        else {
-          fd->is_eof = true;
-          bhead.len = 0;
-        }
-      }
-
-      /* make sure people are not trying to pass bad blend files */
-      if (bhead.len < 0) {
-        fd->is_eof = true;
-      }
-
-      /* bhead now contains the (converted) bhead structure. Now read
-       * the associated data and put everything in a BHeadN (creative naming !)
-       */
-      if (fd->is_eof) {
-        /* pass */
-      }
-#ifdef USE_BHEAD_READ_ON_DEMAND
-      else if (fd->file->seek != NULL && BHEAD_USE_READ_ON_DEMAND(&bhead)) {
-        /* Delay reading bhead content. */
-        new_bhead = MEM_mallocN(sizeof(BHeadN), "new_bhead");
-        if (new_bhead) {
-          new_bhead->next = new_bhead->prev = NULL;
-          new_bhead->file_offset = fd->file->offset;
-          new_bhead->has_data = false;
-          new_bhead->is_memchunk_identical = false;
-          new_bhead->bhead = bhead;
-          off64_t seek_new = fd->file->seek(fd->file, bhead.len, SEEK_CUR);
-          if (seek_new == -1) {
-            fd->is_eof = true;
-            MEM_freeN(new_bhead);
-            new_bhead = NULL;
-          }
-          BLI_assert(fd->file->offset == seek_new);
-        }
-        else {
-          fd->is_eof = true;
-        }
-      }
-#endif
-      else {
-        new_bhead = MEM_mallocN(sizeof(BHeadN) + (size_t)bhead.len, "new_bhead");
-        if (new_bhead) {
-          new_bhead->next = new_bhead->prev = NULL;
-#ifdef USE_BHEAD_READ_ON_DEMAND
-          new_bhead->file_offset = 0; /* don't seek. */
-          new_bhead->has_data = true;
-#endif
-          new_bhead->is_memchunk_identical = false;
-          new_bhead->bhead = bhead;
-
-          readsize = fd->file->read(fd->file, new_bhead + 1, (size_t)bhead.len);
-
-          if (readsize != bhead.len) {
-            fd->is_eof = true;
-            MEM_freeN(new_bhead);
-            new_bhead = NULL;
-          }
-
-          if (fd->flags & FD_FLAGS_IS_MEMFILE) {
-            new_bhead->is_memchunk_identical = ((UndoReader *)fd->file)->memchunk_identical;
-          }
-        }
-        else {
-          fd->is_eof = true;
-        }
-      }
-    }
-  }
-
-  /* We've read a new block. Now add it to the list
-   * of blocks.
-   */
-  if (new_bhead) {
-    BLI_addtail(&fd->bhead_list, new_bhead);
-  }
-
-  return new_bhead;
-}
-
-BHead *blo_bhead_first(FileData *fd)
-{
-  BHeadN *new_bhead;
-  BHead *bhead = NULL;
-
-  /* Rewind the file
-   * Read in a new block if necessary
-   */
-  new_bhead = fd->bhead_list.first;
-  if (new_bhead == NULL) {
-    new_bhead = get_bhead(fd);
-  }
-
-  if (new_bhead) {
-    bhead = &new_bhead->bhead;
-  }
-
-  return bhead;
-}
-
-BHead *blo_bhead_prev(FileData *UNUSED(fd), BHead *thisblock)
-{
-  BHeadN *bheadn = BHEADN_FROM_BHEAD(thisblock);
-  BHeadN *prev = bheadn->prev;
-
-  return (prev) ? &prev->bhead : NULL;
-}
-
-BHead *blo_bhead_next(FileData *fd, BHead *thisblock)
-{
-  BHeadN *new_bhead = NULL;
-  BHead *bhead = NULL;
-
-  if (thisblock) {
-    /* bhead is actually a sub part of BHeadN
-     * We calculate the BHeadN pointer from the BHead pointer below */
-    new_bhead = BHEADN_FROM_BHEAD(thisblock);
-
-    /* get the next BHeadN. If it doesn't exist we read in the next one */
-    new_bhead = new_bhead->next;
-    if (new_bhead == NULL) {
-      new_bhead = get_bhead(fd);
-    }
-  }
-
-  if (new_bhead) {
-    /* here we do the reverse:
-     * go from the BHeadN pointer to the BHead pointer */
-    bhead = &new_bhead->bhead;
-  }
-
-  return bhead;
-}
-
-#ifdef USE_BHEAD_READ_ON_DEMAND
-static bool blo_bhead_read_data(FileData *fd, BHead *thisblock, void *buf)
-{
-  bool success = true;
-  BHeadN *new_bhead = BHEADN_FROM_BHEAD(thisblock);
-  BLI_assert(new_bhead->has_data == false && new_bhead->file_offset != 0);
-  off64_t offset_backup = fd->file->offset;
-  if (UNLIKELY(fd->file->seek(fd->file, new_bhead->file_offset, SEEK_SET) == -1)) {
-    success = false;
-  }
-  else {
-    if (fd->file->read(fd->file, buf, (size_t)new_bhead->bhead.len) != new_bhead->bhead.len) {
-      success = false;
-    }
-    if (fd->flags & FD_FLAGS_IS_MEMFILE) {
-      new_bhead->is_memchunk_identical = ((UndoReader *)fd->file)->memchunk_identical;
-    }
-  }
-  if (fd->file->seek(fd->file, offset_backup, SEEK_SET) == -1) {
-    success = false;
-  }
-  return success;
-}
-
-static BHead *blo_bhead_read_full(FileData *fd, BHead *thisblock)
-{
-  BHeadN *new_bhead = BHEADN_FROM_BHEAD(thisblock);
-  BHeadN *new_bhead_data = MEM_mallocN(sizeof(BHeadN) + new_bhead->bhead.len, "new_bhead");
-  new_bhead_data->bhead = new_bhead->bhead;
-  new_bhead_data->file_offset = new_bhead->file_offset;
-  new_bhead_data->has_data = true;
-  new_bhead_data->is_memchunk_identical = false;
-  if (!blo_bhead_read_data(fd, thisblock, new_bhead_data + 1)) {
-    MEM_freeN(new_bhead_data);
-    return NULL;
-  }
-  return &new_bhead_data->bhead;
-}
-#endif /* USE_BHEAD_READ_ON_DEMAND */
-
-const char *blo_bhead_id_name(const FileData *fd, const BHead *bhead)
-{
-  return (const char *)POINTER_OFFSET(bhead, sizeof(*bhead) + fd->id_name_offset);
-}
-
-AssetMetaData *blo_bhead_id_asset_data_address(const FileData *fd, const BHead *bhead)
-{
-  BLI_assert(blo_bhead_is_id_valid_type(bhead));
-  return (fd->id_asset_data_offset >= 0) ?
-             *(AssetMetaData **)POINTER_OFFSET(bhead, sizeof(*bhead) + fd->id_asset_data_offset) :
-             NULL;
-}
-
-static void decode_blender_header(FileData *fd)
-{
-  char header[SIZEOFBLENDERHEADER], num[4];
-  ssize_t readsize;
-
-  /* read in the header data */
-  readsize = fd->file->read(fd->file, header, sizeof(header));
-
-  if (readsize == sizeof(header) && STREQLEN(header, "BLENDER", 7) && ELEM(header[7], '_', '-') &&
-      ELEM(header[8], 'v', 'V') &&
-      (isdigit(header[9]) && isdigit(header[10]) && isdigit(header[11]))) {
-    fd->flags |= FD_FLAGS_FILE_OK;
-
-    /* what size are pointers in the file ? */
-    if (header[7] == '_') {
-      fd->flags |= FD_FLAGS_FILE_POINTSIZE_IS_4;
-      if (sizeof(void *) != 4) {
-        fd->flags |= FD_FLAGS_POINTSIZE_DIFFERS;
-      }
-    }
-    else {
-      if (sizeof(void *) != 8) {
-        fd->flags |= FD_FLAGS_POINTSIZE_DIFFERS;
-      }
-    }
-
-    /* is the file saved in a different endian
-     * than we need ?
-     */
-    if (((header[8] == 'v') ? L_ENDIAN : B_ENDIAN) != ENDIAN_ORDER) {
-      fd->flags |= FD_FLAGS_SWITCH_ENDIAN;
-    }
-
-    /* get the version number */
-    memcpy(num, header + 9, 3);
-    num[3] = 0;
-    fd->fileversion = atoi(num);
-  }
-}
-
-/**
- * \return Success if the file is read correctly, else set \a r_error_message.
- */
-static bool read_file_dna(FileData *fd, const char **r_error_message)
-{
-  BHead *bhead;
-  int subversion = 0;
-
-  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
-    if (bhead->code == GLOB) {
-      /* Before this, the subversion didn't exist in 'FileGlobal' so the subversion
-       * value isn't accessible for the purpose of DNA versioning in this case. */
-      if (fd->fileversion <= 242) {
-        continue;
-      }
-      /* We can't use read_global because this needs 'DNA1' to be decoded,
-       * however the first 4 chars are _always_ the subversion. */
-      FileGlobal *fg = (void *)&bhead[1];
-      BLI_STATIC_ASSERT(offsetof(FileGlobal, subvstr) == 0, "Must be first: subvstr")
-      char num[5];
-      memcpy(num, fg->subvstr, 4);
-      num[4] = 0;
-      subversion = atoi(num);
-    }
-    else if (bhead->code == DNA1) {
-      const bool do_endian_swap = (fd->flags & FD_FLAGS_SWITCH_ENDIAN) != 0;
-
-      fd->filesdna = DNA_sdna_from_data(
-          &bhead[1], bhead->len, do_endian_swap, true, r_error_message);
-      if (fd->filesdna) {
-        blo_do_versions_dna(fd->filesdna, fd->fileversion, subversion);
-        fd->compflags = DNA_struct_get_compareflags(fd->filesdna, fd->memsdna);
-        fd->reconstruct_info = DNA_reconstruct_info_create(
-            fd->filesdna, fd->memsdna, fd->compflags);
-        /* used to retrieve ID names from (bhead+1) */
-        fd->id_name_offset = DNA_elem_offset(fd->filesdna, "ID", "char", "name[]");
-        BLI_assert(fd->id_name_offset != -1);
-        fd->id_asset_data_offset = DNA_elem_offset(
-            fd->filesdna, "ID", "AssetMetaData", "*asset_data");
-
-        return true;
-      }
-
-      return false;
-    }
-    else if (bhead->code == ENDB) {
-      break;
-    }
-  }
-
-  *r_error_message = "Missing DNA block";
-  return false;
-}
-
-static int *read_file_thumbnail(FileData *fd)
-{
-  BHead *bhead;
-  int *blend_thumb = NULL;
-
-  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
-    if (bhead->code == TEST) {
-      const bool do_endian_swap = (fd->flags & FD_FLAGS_SWITCH_ENDIAN) != 0;
-      int *data = (int *)(bhead + 1);
-
-      if (bhead->len < (sizeof(int[2]))) {
-        break;
-      }
-
-      if (do_endian_swap) {
-        BLI_endian_switch_int32(&data[0]);
-        BLI_endian_switch_int32(&data[1]);
-      }
-
-      const int width = data[0];
-      const int height = data[1];
-      if (!BLEN_THUMB_MEMSIZE_IS_VALID(width, height)) {
-        break;
-      }
-      if (bhead->len < BLEN_THUMB_MEMSIZE_FILE(width, height)) {
-        break;
-      }
-
-      blend_thumb = data;
-      break;
-    }
-    if (bhead->code != REND) {
-      /* Thumbnail is stored in TEST immediately after first REND... */
-      break;
-    }
-  }
-
-  return blend_thumb;
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name File Data API
- * \{ */
-
-static FileData *filedata_new(BlendFileReadReport *reports)
-{
-  BLI_assert(reports != NULL);
-
-  FileData *fd = MEM_callocN(sizeof(FileData), "FileData");
-
-  fd->memsdna = DNA_sdna_current_get();
-
-  fd->datamap = oldnewmap_new();
-  fd->globmap = oldnewmap_new();
-  fd->libmap = oldnewmap_new();
-
-  fd->reports = reports;
-
-  return fd;
-}
-
-static FileData *blo_decode_and_check(FileData *fd, ReportList *reports)
-{
-  decode_blender_header(fd);
-
-  if (fd->flags & FD_FLAGS_FILE_OK) {
-    const char *error_message = NULL;
-    if (read_file_dna(fd, &error_message) == false) {
-      BKE_reportf(
-          reports, RPT_ERROR, "Failed to read blend file '%s': %s", fd->relabase, error_message);
-      blo_filedata_free(fd);
-      fd = NULL;
-    }
-  }
-  else {
-    BKE_reportf(
-        reports, RPT_ERROR, "Failed to read blend file '%s', not a blend file", fd->relabase);
-    blo_filedata_free(fd);
-    fd = NULL;
-  }
-
-  return fd;
-}
-
-static FileData *blo_filedata_from_file_descriptor(const char *filepath,
-                                                   BlendFileReadReport *reports,
-                                                   int filedes)
-{
-  char header[7];
-  FileReader *rawfile = BLI_filereader_new_file(filedes);
-  FileReader *file = NULL;
-
-  errno = 0;
-  /* If opening the file failed or we can't read the header, give up. */
-  if (rawfile == NULL || rawfile->read(rawfile, header, sizeof(header)) != sizeof(header)) {
-    BKE_reportf(reports->reports,
-                RPT_WARNING,
-                "Unable to read '%s': %s",
-                filepath,
-                errno ? strerror(errno) : TIP_("insufficient content"));
-    if (rawfile) {
-      rawfile->close(rawfile);
-    }
-    else {
-      close(filedes);
-    }
-    return NULL;
-  }
-
-  /* Rewind the file after reading the header. */
-  rawfile->seek(rawfile, 0, SEEK_SET);
-
-  /* Check if we have a regular file. */
-  if (memcmp(header, "BLENDER", sizeof(header)) == 0) {
-    /* Try opening the file with memory-mapped IO. */
-    file = BLI_filereader_new_mmap(filedes);
-    if (file == NULL) {
-      /* mmap failed, so just keep using rawfile. */
-      file = rawfile;
-      rawfile = NULL;
-    }
-  }
-  else if (BLI_file_magic_is_gzip(header)) {
-    file = BLI_filereader_new_gzip(rawfile);
-    if (file != NULL) {
-      rawfile = NULL; /* The `Gzip` #FileReader takes ownership of `rawfile`. */
-    }
-  }
-  else if (BLI_file_magic_is_zstd(header)) {
-    file = BLI_filereader_new_zstd(rawfile);
-    if (file != NULL) {
-      rawfile = NULL; /* The `Zstd` #FileReader takes ownership of `rawfile`. */
-    }
-  }
-
-  /* Clean up `rawfile` if it wasn't taken over. */
-  if (rawfile != NULL) {
-    rawfile->close(rawfile);
-  }
-  if (file == NULL) {
-    BKE_reportf(reports->reports, RPT_WARNING, "Unrecognized file format '%s'", filepath);
-    return NULL;
-  }
-
-  FileData *fd = filedata_new(reports);
-  fd->file = file;
-
-  return fd;
-}
-
-static FileData *blo_filedata_from_file_open(const char *filepath, BlendFileReadReport *reports)
-{
-  errno = 0;
-  const int file = BLI_open(filepath, O_BINARY | O_RDONLY, 0);
-  if (file == -1) {
-    BKE_reportf(reports->reports,
-                RPT_WARNING,
-                "Unable to open '%s': %s",
-                filepath,
-                errno ? strerror(errno) : TIP_("unknown error reading file"));
-    return NULL;
-  }
-  return blo_filedata_from_file_descriptor(filepath, reports, file);
-}
-
-FileData *blo_filedata_from_file(const char *filepath, BlendFileReadReport *reports)
-{
-  FileData *fd = blo_filedata_from_file_open(filepath, reports);
-  if (fd != NULL) {
-    /* needed for library_append and read_libraries */
-    BLI_strncpy(fd->relabase, filepath, sizeof(fd->relabase));
-
-    return blo_decode_and_check(fd, reports->reports);
-  }
-  return NULL;
-}
-
-/**
- * Same as blo_filedata_from_file(), but does not reads DNA data, only header.
- * Use it for light access (e.g. thumbnail reading).
- */
-static FileData *blo_filedata_from_file_minimal(const char *filepath)
-{
-  FileData *fd = blo_filedata_from_file_open(filepath, &(BlendFileReadReport){.reports = NULL});
-  if (fd != NULL) {
-    decode_blender_header(fd);
-    if (fd->flags & FD_FLAGS_FILE_OK) {
-      return fd;
-    }
-    blo_filedata_free(fd);
-  }
-  return NULL;
-}
-
-FileData *blo_filedata_from_memory(const void *mem, int memsize, BlendFileReadReport *reports)
-{
-  if (!mem || memsize < SIZEOFBLENDERHEADER) {
-    BKE_report(
-        reports->reports, RPT_WARNING, (mem) ? TIP_("Unable to read") : TIP_("Unable to open"));
-    return NULL;
-  }
-
-  FileReader *mem_file = BLI_filereader_new_memory(mem, memsize);
-  FileReader *file = mem_file;
-
-  if (BLI_file_magic_is_gzip(mem)) {
-    file = BLI_filereader_new_gzip(mem_file);
-  }
-  else if (BLI_file_magic_is_zstd(mem)) {
-    file = BLI_filereader_new_zstd(mem_file);
-  }
-
-  if (file == NULL) {
-    /* Compression initialization failed. */
-    mem_file->close(mem_file);
-    return NULL;
-  }
-
-  FileData *fd = filedata_new(reports);
-  fd->file = file;
-
-  return blo_decode_and_check(fd, reports->reports);
-}
-
-FileData *blo_filedata_from_memfile(MemFile *memfile,
-                                    const struct BlendFileReadParams *params,
-                                    BlendFileReadReport *reports)
-{
-  if (!memfile) {
-    BKE_report(reports->reports, RPT_WARNING, "Unable to open blend ");
-    return NULL;
-  }
-
-  FileData *fd = filedata_new(reports);
-  fd->file = BLO_memfile_new_filereader(memfile, params->undo_direction);
-  fd->undo_direction = params->undo_direction;
-  fd->flags |= FD_FLAGS_IS_MEMFILE;
-
-  return blo_decode_and_check(fd, reports->reports);
-}
-
-void blo_filedata_free(FileData *fd)
-{
-  if (fd) {
-
-    /* Free all BHeadN data blocks */
-#ifndef NDEBUG
-    BLI_freelistN(&fd->bhead_list);
-#else
-    /* Sanity check we're not keeping memory we don't need. */
-    LISTBASE_FOREACH_MUTABLE (BHeadN *, new_bhead, &fd->bhead_list) {
-      if (fd->file->seek != NULL && BHEAD_USE_READ_ON_DEMAND(&new_bhead->bhead)) {
-        BLI_assert(new_bhead->has_data == 0);
-      }
-      MEM_freeN(new_bhead);
-    }
-#endif
-    fd->file->close(fd->file);
-
-    if (fd->filesdna) {
-      DNA_sdna_free(fd->filesdna);
-    }
-    if (fd->compflags) {
-      MEM_freeN((void *)fd->compflags);
-    }
-    if (fd->reconstruct_info) {
-      DNA_reconstruct_info_free(fd->reconstruct_info);
-    }
-
-    if (fd->datamap) {
-      oldnewmap_free(fd->datamap);
-    }
-    if (fd->globmap) {
-      oldnewmap_free(fd->globmap);
-    }
-    if (fd->packedmap) {
-      oldnewmap_free(fd->packedmap);
-    }
-    if (fd->libmap && !(fd->flags & FD_FLAGS_NOT_MY_LIBMAP)) {
-      oldnewmap_free(fd->libmap);
-    }
-    if (fd->old_idmap != NULL) {
-      BKE_main_idmap_destroy(fd->old_idmap);
-    }
-    blo_cache_storage_end(fd);
-    if (fd->bheadmap) {
-      MEM_freeN(fd->bheadmap);
-    }
-
-#ifdef USE_GHASH_BHEAD
-    if (fd->bhead_idname_hash) {
-      BLI_ghash_free(fd->bhead_idname_hash, NULL, NULL);
-    }
-#endif
-
-    MEM_freeN(fd);
-  }
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Public Utilities
- * \{ */
-
-bool BLO_has_bfile_extension(const char *str)
-{
-  const char *ext_test[4] = {".blend", ".ble", ".blend.gz", NULL};
-  return BLI_path_extension_check_array(str, ext_test);
-}
-
-bool BLO_library_path_explode(const char *path, char *r_dir, char **r_group, char **r_name)
-{
-  /* We might get some data names with slashes,
-   * so we have to go up in path until we find blend file itself,
-   * then we know next path item is group, and everything else is data name. */
-  char *slash = NULL, *prev_slash = NULL, c = '\0';
-
-  r_dir[0] = '\0';
-  if (r_group) {
-    *r_group = NULL;
-  }
-  if (r_name) {
-    *r_name = NULL;
-  }
-
-  /* if path leads to an existing directory, we can be sure we're not (in) a library */
-  if (BLI_is_dir(path)) {
-    return false;
-  }
-
-  strcpy(r_dir, path);
-
-  while ((slash = (char *)BLI_path_slash_rfind(r_dir))) {
-    char tc = *slash;
-    *slash = '\0';
-    if (BLO_has_bfile_extension(r_dir) && BLI_is_file(r_dir)) {
-      break;
-    }
-    if (STREQ(r_dir, BLO_EMBEDDED_STARTUP_BLEND)) {
-      break;
-    }
-
-    if (prev_slash) {
-      *prev_slash = c;
-    }
-    prev_slash = slash;
-    c = tc;
-  }
-
-  if (!slash) {
-    return false;
-  }
-
-  if (slash[1] != '\0') {
-    BLI_assert(strlen(slash + 1) < BLO_GROUP_MAX);
-    if (r_group) {
-      *r_group = slash + 1;
-    }
-  }
-
-  if (prev_slash && (prev_slash[1] != '\0')) {
-    BLI_assert(strlen(prev_slash + 1) < MAX_ID_NAME - 2);
-    if (r_name) {
-      *r_name = prev_slash + 1;
-    }
-  }
-
-  return true;
-}
-
-BlendThumbnail *BLO_thumbnail_from_file(const char *filepath)
-{
-  FileData *fd;
-  BlendThumbnail *data = NULL;
-  int *fd_data;
-
-  fd = blo_filedata_from_file_minimal(filepath);
-  fd_data = fd ? read_file_thumbnail(fd) : NULL;
-
-  if (fd_data) {
-    const int width = fd_data[0];
-    const int height = fd_data[1];
-    if (BLEN_THUMB_MEMSIZE_IS_VALID(width, height)) {
-      const size_t data_size = BLEN_THUMB_MEMSIZE(width, height);
-      data = MEM_mallocN(data_size, __func__);
-      if (data) {
-        BLI_assert((data_size - sizeof(*data)) ==
-                   (BLEN_THUMB_MEMSIZE_FILE(width, height) - (sizeof(*fd_data) * 2)));
-        data->width = width;
-        data->height = height;
-        memcpy(data->rect, &fd_data[2], data_size - sizeof(*data));
-      }
-    }
-  }
-
-  blo_filedata_free(fd);
-
-  return data;
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Old/New Pointer Map
- * \{ */
-
-/* Only direct data-blocks. */
-static void *newdataadr(FileData *fd, const void *adr)
-{
-  return oldnewmap_lookup_and_inc(fd->datamap, adr, true);
-}
-
-/* Only direct data-blocks. */
-static void *newdataadr_no_us(FileData *fd, const void *adr)
-{
-  return oldnewmap_lookup_and_inc(fd->datamap, adr, false);
-}
-
-void *blo_read_get_new_globaldata_address(FileData *fd, const void *adr)
-{
-  return oldnewmap_lookup_and_inc(fd->globmap, adr, true);
-}
-
-/* Used to restore packed data after undo. */
-static void *newpackedadr(FileData *fd, const void *adr)
-{
-  if (fd->packedmap && adr) {
-    return oldnewmap_lookup_and_inc(fd->packedmap, adr, true);
-  }
-
-  return oldnewmap_lookup_and_inc(fd->datamap, adr, true);
-}
-
-/* only lib data */
-static void *newlibadr(FileData *fd, const void *lib, const void *adr)
-{
-  return oldnewmap_liblookup(fd->libmap, adr, lib);
-}
-
-void *blo_do_versions_newlibadr(FileData *fd, const void *lib, const void *adr)
-{
-  return newlibadr(fd, lib, adr);
-}
-
-/* increases user number */
-static void change_link_placeholder_to_real_ID_pointer_fd(FileData *fd, const void *old, void *new)
-{
-  for (int i = 0; i < fd->libmap->nentries; i++) {
-    OldNew *entry = &fd->libmap->entries[i];
-
-    if (old == entry->newp && entry->nr == ID_LINK_PLACEHOLDER) {
-      entry->newp = new;
-      if (new) {
-        entry->nr = GS(((ID *)new)->name);
-      }
-    }
-  }
-}
-
-static void change_link_placeholder_to_real_ID_pointer(ListBase *mainlist,
-                                                       FileData *basefd,
-                                                       void *old,
-                                                       void *new)
-{
-  LISTBASE_FOREACH (Main *, mainptr, mainlist) {
-    FileData *fd;
-
-    if (mainptr->curlib) {
-      fd = mainptr->curlib->filedata;
-    }
-    else {
-      fd = basefd;
-    }
-
-    if (fd) {
-      change_link_placeholder_to_real_ID_pointer_fd(fd, old, new);
-    }
-  }
-}
-
-/* XXX disabled this feature - packed files also belong in temp saves and quit.blend,
- * to make restore work. */
-
-static void insert_packedmap(FileData *fd, PackedFile *pf)
-{
-  oldnewmap_insert(fd->packedmap, pf, pf, 0);
-  oldnewmap_insert(fd->packedmap, pf->data, pf->data, 0);
-}
-
-void blo_make_packed_pointer_map(FileData *fd, Main *oldmain)
-{
-  fd->packedmap = oldnewmap_new();
-
-  LISTBASE_FOREACH (Image *, ima, &oldmain->images) {
-    if (ima->packedfile) {
-      insert_packedmap(fd, ima->packedfile);
-    }
-
-    LISTBASE_FOREACH (ImagePackedFile *, imapf, &ima->packedfiles) {
-      if (imapf->packedfile) {
-        insert_packedmap(fd, imapf->packedfile);
-      }
-    }
-  }
-
-  LISTBASE_FOREACH (VFont *, vfont, &oldmain->fonts) {
-    if (vfont->packedfile) {
-      insert_packedmap(fd, vfont->packedfile);
-    }
-  }
-
-  LISTBASE_FOREACH (bSound *, sound, &oldmain->sounds) {
-    if (sound->packedfile) {
-      insert_packedmap(fd, sound->packedfile);
-    }
-  }
-
-  LISTBASE_FOREACH (Volume *, volume, &oldmain->volumes) {
-    if (volume->packedfile) {
-      insert_packedmap(fd, volume->packedfile);
-    }
-  }
-
-  LISTBASE_FOREACH (Library *, lib, &oldmain->libraries) {
-    if (lib->packedfile) {
-      insert_packedmap(fd, lib->packedfile);
-    }
-  }
-}
-
-void blo_end_packed_pointer_map(FileData *fd, Main *oldmain)
-{
-  OldNew *entry = fd->packedmap->entries;
-
-  /* used entries were restored, so we put them to zero */
-  for (int i = 0; i < fd->packedmap->nentries; i++, entry++) {
-    if (entry->nr > 0) {
-      entry->newp = NULL;
-    }
-  }
-
-  LISTBASE_FOREACH (Image *, ima, &oldmain->images) {
-    ima->packedfile = newpackedadr(fd, ima->packedfile);
-
-    LISTBASE_FOREACH (ImagePackedFile *, imapf, &ima->packedfiles) {
-      imapf->packedfile = newpackedadr(fd, imapf->packedfile);
-    }
-  }
-
-  LISTBASE_FOREACH (VFont *, vfont, &oldmain->fonts) {
-    vfont->packedfile = newpackedadr(fd, vfont->packedfile);
-  }
-
-  LISTBASE_FOREACH (bSound *, sound, &oldmain->sounds) {
-    sound->packedfile = newpackedadr(fd, sound->packedfile);
-  }
-
-  LISTBASE_FOREACH (Library *, lib, &oldmain->libraries) {
-    lib->packedfile = newpackedadr(fd, lib->packedfile);
-  }
-
-  LISTBASE_FOREACH (Volume *, volume, &oldmain->volumes) {
-    volume->packedfile = newpackedadr(fd, volume->packedfile);
-  }
-}
-
-void blo_add_library_pointer_map(ListBase *old_mainlist, FileData *fd)
-{
-  ListBase *lbarray[INDEX_ID_MAX];
-
-  LISTBASE_FOREACH (Main *, ptr, old_mainlist) {
-    int i = set_listbasepointers(ptr, lbarray);
-    while (i--) {
-      LISTBASE_FOREACH (ID *, id, lbarray[i]) {
-        oldnewmap_insert(fd->libmap, id, id, GS(id->name));
-      }
-    }
-  }
-
-  fd->old_mainlist = old_mainlist;
-}
-
-void blo_make_old_idmap_from_main(FileData *fd, Main *bmain)
-{
-  if (fd->old_idmap != NULL) {
-    BKE_main_idmap_destroy(fd->old_idmap);
-  }
-  fd->old_idmap = BKE_main_idmap_create(bmain, false, NULL, MAIN_IDMAP_TYPE_UUID);
-}
-
-typedef struct BLOCacheStorage {
-  GHash *cache_map;
-  MemArena *memarena;
-} BLOCacheStorage;
-
-typedef struct BLOCacheStorageValue {
-  void *cache_v;
-  uint new_usage_count;
-} BLOCacheStorageValue;
-
-/** Register a cache data entry to be preserved when reading some undo memfile. */
-static void blo_cache_storage_entry_register(
-    ID *id, const IDCacheKey *key, void **cache_p, uint UNUSED(flags), void *cache_storage_v)
-{
-  BLI_assert(key->id_session_uuid == id->session_uuid);
-  UNUSED_VARS_NDEBUG(id);
-
-  BLOCacheStorage *cache_storage = cache_storage_v;
-  BLI_assert(!BLI_ghash_haskey(cache_storage->cache_map, key));
-
-  IDCacheKey *storage_key = BLI_memarena_alloc(cache_storage->memarena, sizeof(*storage_key));
-  *storage_key = *key;
-  BLOCacheStorageValue *storage_value = BLI_memarena_alloc(cache_storage->memarena,
-                                                           sizeof(*storage_value));
-  storage_value->cache_v = *cache_p;
-  storage_value->new_usage_count = 0;
-  BLI_ghash_insert(cache_storage->cache_map, storage_key, storage_value);
-}
-
-/** Restore a cache data entry from old ID into new one, when reading some undo memfile. */
-static void blo_cache_storage_entry_restore_in_new(
-    ID *UNUSED(id), const IDCacheKey *key, void **cache_p, uint flags, void *cache_storage_v)
-{
-  BLOCacheStorage *cache_storage = cache_storage_v;
-
-  if (cache_storage == NULL) {
-    /* In non-undo case, only clear the pointer if it is a purely runtime one.
-     * If it may be stored in a persistent way in the .blend file, direct_link code is responsible
-     * to properly deal with it. */
-    if ((flags & IDTYPE_CACHE_CB_FLAGS_PERSISTENT) == 0) {
-      *cache_p = NULL;
-    }
-    return;
-  }
-
-  BLOCacheStorageValue *storage_value = BLI_ghash_lookup(cache_storage->cache_map, key);
-  if (storage_value == NULL) {
-    *cache_p = NULL;
-    return;
-  }
-  storage_value->new_usage_count++;
-  *cache_p = storage_value->cache_v;
-}
-
-/** Clear as needed a cache data entry from old ID, when reading some undo memfile. */
-static void blo_cache_storage_entry_clear_in_old(ID *UNUSED(id),
-                                                 const IDCacheKey *key,
-                                                 void **cache_p,
-                                                 uint UNUSED(flags),
-                                                 void *cache_storage_v)
-{
-  BLOCacheStorage *cache_storage = cache_storage_v;
-
-  BLOCacheStorageValue *storage_value = BLI_ghash_lookup(cache_storage->cache_map, key);
-  if (storage_value == NULL) {
-    *cache_p = NULL;
-    return;
-  }
-  /* If that cache has been restored into some new ID, we want to remove it from old one, otherwise
-   * keep it there so that it gets properly freed together with its ID. */
-  if (storage_value->new_usage_count != 0) {
-    *cache_p = NULL;
-  }
-  else {
-    BLI_assert(*cache_p == storage_value->cache_v);
-  }
-}
-
-void blo_cache_storage_init(FileData *fd, Main *bmain)
-{
-  if (fd->flags & FD_FLAGS_IS_MEMFILE) {
-    BLI_assert(fd->cache_storage == NULL);
-    fd->cache_storage = MEM_mallocN(sizeof(*fd->cache_storage), __func__);
-    fd->cache_storage->memarena = BLI_memarena_new(BLI_MEMARENA_STD_BUFSIZE, __func__);
-    fd->cache_storage->cache_map = BLI_ghash_new(
-        BKE_idtype_cache_key_hash, BKE_idtype_cache_key_cmp, __func__);
-
-    ListBase *lb;
-    FOREACH_MAIN_LISTBASE_BEGIN (bmain, lb) {
-      ID *id = lb->first;
-      if (id == NULL) {
-        continue;
-      }
-
-      const IDTypeInfo *type_info = BKE_idtype_get_info_from_id(id);
-      if (type_info->foreach_cache == NULL) {
-        continue;
-      }
-
-      FOREACH_MAIN_LISTBASE_ID_BEGIN (lb, id) {
-        if (ID_IS_LINKED(id)) {
-          continue;
-        }
-        BKE_idtype_id_foreach_cache(id, blo_cache_storage_entry_register, fd->cache_storage);
-      }
-      FOREACH_MAIN_LISTBASE_ID_END;
-    }
-    FOREACH_MAIN_LISTBASE_END;
-  }
-  else {
-    fd->cache_storage = NULL;
-  }
-}
-
-void blo_cache_storage_old_bmain_clear(FileData *fd, Main *bmain_old)
-{
-  if (fd->cache_storage != NULL) {
-    ListBase *lb;
-    FOREACH_MAIN_LISTBASE_BEGIN (bmain_old, lb) {
-      ID *id = lb->first;
-      if (id == NULL) {
-        continue;
-      }
-
-      const IDTypeInfo *type_info = BKE_idtype_get_info_from_id(id);
-      if (type_info->foreach_cache == NULL) {
-        continue;
-      }
-
-      FOREACH_MAIN_LISTBASE_ID_BEGIN (lb, id) {
-        if (ID_IS_LINKED(id)) {
-          continue;
-        }
-        BKE_idtype_id_foreach_cache(id, blo_cache_storage_entry_clear_in_old, fd->cache_storage);
-      }
-      FOREACH_MAIN_LISTBASE_ID_END;
-    }
-    FOREACH_MAIN_LISTBASE_END;
-  }
-}
-
-void blo_cache_storage_end(FileData *fd)
-{
-  if (fd->cache_storage != NULL) {
-    BLI_ghash_free(fd->cache_storage->cache_map, NULL, NULL);
-    BLI_memarena_free(fd->cache_storage->memarena);
-    MEM_freeN(fd->cache_storage);
-    fd->cache_storage = NULL;
-  }
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name DNA Struct Loading
- * \{ */
-
-static void switch_endian_structs(const struct SDNA *filesdna, BHead *bhead)
-{
-  int blocksize, nblocks;
-  char *data;
-
-  data = (char *)(bhead + 1);
-  blocksize = filesdna->types_size[filesdna->structs[bhead->SDNAnr]->type];
-
-  nblocks = bhead->nr;
-  while (nblocks--) {
-    DNA_struct_switch_endian(filesdna, bhead->SDNAnr, data);
-
-    data += blocksize;
-  }
-}
-
-static void *read_struct(FileData *fd, BHead *bh, const char *blockname)
-{
-  void *temp = NULL;
-
-  if (bh->len) {
-#ifdef USE_BHEAD_READ_ON_DEMAND
-    BHead *bh_orig = bh;
-#endif
-
-    /* switch is based on file dna */
-    if (bh->SDNAnr && (fd->flags & FD_FLAGS_SWITCH_ENDIAN)) {
-#ifdef USE_BHEAD_READ_ON_DEMAND
-      if (BHEADN_FROM_BHEAD(bh)->has_data == false) {
-        bh = blo_bhead_read_full(fd, bh);
-        if (UNLIKELY(bh == NULL)) {
-          fd->flags &= ~FD_FLAGS_FILE_OK;
-          return NULL;
-        }
-      }
-#endif
-      switch_endian_structs(fd->filesdna, bh);
-    }
-
-    if (fd->compflags[bh->SDNAnr] != SDNA_CMP_REMOVED) {
-      if (fd->compflags[bh->SDNAnr] == SDNA_CMP_NOT_EQUAL) {
-#ifdef USE_BHEAD_READ_ON_DEMAND
-        if (BHEADN_FROM_BHEAD(bh)->has_data == false) {
-          bh = blo_bhead_read_full(fd, bh);
-          if (UNLIKELY(bh == NULL)) {
-            fd->flags &= ~FD_FLAGS_FILE_OK;
-            return NULL;
-          }
-        }
-#endif
-        temp = DNA_struct_reconstruct(fd->reconstruct_info, bh->SDNAnr, bh->nr, (bh + 1));
-      }
-      else {
-        /* SDNA_CMP_EQUAL */
-        temp = MEM_mallocN(bh->len, blockname);
-#ifdef USE_BHEAD_READ_ON_DEMAND
-        if (BHEADN_FROM_BHEAD(bh)->has_data) {
-          memcpy(temp, (bh + 1), bh->len);
-        }
-        else {
-          /* Instead of allocating the bhead, then copying it,
-           * read the data from the file directly into the memory. */
-          if (UNLIKELY(!blo_bhead_read_data(fd, bh, temp))) {
-            fd->flags &= ~FD_FLAGS_FILE_OK;
-            MEM_freeN(temp);
-            temp = NULL;
-          }
-        }
-#else
-        memcpy(temp, (bh + 1), bh->len);
-#endif
-      }
-    }
-
-#ifdef USE_BHEAD_READ_ON_DEMAND
-    if (bh_orig != bh) {
-      MEM_freeN(BHEADN_FROM_BHEAD(bh));
-    }
-#endif
-  }
-
-  return temp;
-}
-
-/* Like read_struct, but gets a pointer without allocating. Only works for
- * undo since DNA must match. */
-static const void *peek_struct_undo(FileData *fd, BHead *bhead)
-{
-  BLI_assert(fd->flags & FD_FLAGS_IS_MEMFILE);
-  UNUSED_VARS_NDEBUG(fd);
-  return (bhead->len) ? (const void *)(bhead + 1) : NULL;
-}
-
-static void link_glob_list(FileData *fd, ListBase *lb) /* for glob data */
-{
-  Link *ln, *prev;
-  void *poin;
-
-  if (BLI_listbase_is_empty(lb)) {
-    return;
-  }
-  poin = newdataadr(fd, lb->first);
-  if (lb->first) {
-    oldnewmap_insert(fd->globmap, lb->first, poin, 0);
-  }
-  lb->first = poin;
-
-  ln = lb->first;
-  prev = NULL;
-  while (ln) {
-    poin = newdataadr(fd, ln->next);
-    if (ln->next) {
-      oldnewmap_insert(fd->globmap, ln->next, poin, 0);
-    }
-    ln->next = poin;
-    ln->prev = prev;
-    prev = ln;
-    ln = ln->next;
-  }
-  lb->last = prev;
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Read ID
- * \{ */
-
-static void lib_link_id(BlendLibReader *reader, ID *id);
-
-static void lib_link_id_embedded_id(BlendLibReader *reader, ID *id)
-{
-
-  /* Handle 'private IDs'. */
-  bNodeTree *nodetree = ntreeFromID(id);
-  if (nodetree != NULL) {
-    lib_link_id(reader, &nodetree->id);
-    ntreeBlendReadLib(reader, nodetree);
-  }
-
-  if (GS(id->name) == ID_SCE) {
-    Scene *scene = (Scene *)id;
-    if (scene->master_collection != NULL) {
-      lib_link_id(reader, &scene->master_collection->id);
-      BKE_collection_blend_read_lib(reader, scene->master_collection);
-    }
-  }
-}
-
-static void lib_link_id(BlendLibReader *reader, ID *id)
-{
-  /* NOTE: WM IDProperties are never written to file, hence they should always be NULL here. */
-  BLI_assert((GS(id->name) != ID_WM) || id->properties == NULL);
-  IDP_BlendReadLib(reader, id->properties);
-
-  AnimData *adt = BKE_animdata_from_id(id);
-  if (adt != NULL) {
-    BKE_animdata_blend_read_lib(reader, id, adt);
-  }
-
-  if (id->override_library) {
-    BLO_read_id_address(reader, id->lib, &id->override_library->reference);
-    BLO_read_id_address(reader, id->lib, &id->override_library->storage);
-    BLO_read_id_address(reader, id->lib, &id->override_library->hierarchy_root);
-  }
-
-  lib_link_id_embedded_id(reader, id);
-}
-
-static void direct_link_id_override_property_operation_cb(BlendDataReader *reader, void *data)
-{
-  IDOverrideLibraryPropertyOperation *opop = data;
-
-  BLO_read_data_address(reader, &opop->subitem_reference_name);
-  BLO_read_data_address(reader, &opop->subitem_local_name);
-
-  opop->tag = 0; /* Runtime only. */
-}
-
-static void direct_link_id_override_property_cb(BlendDataReader *reader, void *data)
-{
-  IDOverrideLibraryProperty *op = data;
-
-  BLO_read_data_address(reader, &op->rna_path);
-
-  op->tag = 0; /* Runtime only. */
-
-  BLO_read_list_cb(reader, &op->operations, direct_link_id_override_property_operation_cb);
-}
-
-static void direct_link_id_common(
-    BlendDataReader *reader, Library *current_library, ID *id, ID *id_old, const int tag);
-
-static void direct_link_id_embedded_id(BlendDataReader *reader,
-                                       Library *current_library,
-                                       ID *id,
-                                       ID *id_old)
-{
-  /* Handle 'private IDs'. */
-  bNodeTree **nodetree = BKE_ntree_ptr_from_id(id);
-  if (nodetree != NULL && *nodetree != NULL) {
-    BLO_read_data_address(reader, nodetree);
-    direct_link_id_common(reader,
-                          current_library,
-                          (ID *)*nodetree,
-                          id_old != NULL ? (ID *)ntreeFromID(id_old) : NULL,
-                          0);
-    ntreeBlendReadData(reader, *nodetree);
-  }
-
-  if (GS(id->name) == ID_SCE) {
-    Scene *scene = (Scene *)id;
-    if (scene->master_collection != NULL) {
-      BLO_read_data_address(reader, &scene->master_collection);
-      direct_link_id_common(reader,
-                            current_library,
-                            &scene->master_collection->id,
-                            id_old != NULL ? &((Scene *)id_old)->master_collection->id : NULL,
-                            0);
-      BKE_collection_blend_read_data(reader, scene->master_collection);
-    }
-  }
-}
-
-static int direct_link_id_restore_recalc_exceptions(const ID *id_current)
-{
-  /* Exception for armature objects, where the pose has direct points to the
-   * armature data-block. */
-  if (GS(id_current->name) == ID_OB && ((Object *)id_current)->pose) {
-    return ID_RECALC_GEOMETRY;
-  }
-
-  return 0;
-}
-
-static int direct_link_id_restore_recalc(const FileData *fd,
-                                         const ID *id_target,
-                                         const ID *id_current,
-                                         const bool is_identical)
-{
-  /* These are the evaluations that had not been performed yet at the time the
-   * target undo state was written. These need to be done again, since they may
-   * flush back changes to the original datablock. */
-  int recalc = id_target->recalc;
-
-  if (id_current == NULL) {
-    /* ID does not currently exist in the database, so also will not exist in
-     * the dependency graphs. That means it will be newly created and as a
-     * result also fully re-evaluated regardless of the recalc flag set here. */
-    recalc |= ID_RECALC_ALL;
-  }
-  else {
-    /* If the contents datablock changed, the depsgraph needs to copy the
-     * datablock again to ensure it matches the original datablock. */
-    if (!is_identical) {
-      recalc |= ID_RECALC_COPY_ON_WRITE;
-    }
-
-    /* Special exceptions. */
-    recalc |= direct_link_id_restore_recalc_exceptions(id_current);
-
-    /* Evaluations for the current state that have not been performed yet
-     * by the time we are performing this undo step. */
-    recalc |= id_current->recalc;
-
-    /* Tags that were set between the target state and the current state,
-     * that we need to perform again. */
-    if (fd->undo_direction == STEP_UNDO) {
-      /* Undo: tags from target to the current state. */
-      recalc |= id_current->recalc_up_to_undo_push;
-    }
-    else {
-      BLI_assert(fd->undo_direction == STEP_REDO);
-      /* Redo: tags from current to the target state. */
-      recalc |= id_target->recalc_up_to_undo_push;
-    }
-  }
-
-  return recalc;
-}
-
-static void direct_link_id_common(
-    BlendDataReader *reader, Library *current_library, ID *id, ID *id_old, const int tag)
-{
-  if (!BLO_read_data_is_undo(reader)) {
-    /* When actually reading a file, we do want to reset/re-generate session uuids.
-     * In undo case, we want to re-use existing ones. */
-    id->session_uuid = MAIN_ID_SESSION_UUID_UNSET;
-  }
-
-  if ((tag & LIB_TAG_TEMP_MAIN) == 0) {
-    BKE_lib_libblock_session_uuid_ensure(id);
-  }
-
-  id->lib = current_library;
-  id->us = ID_FAKE_USERS(id);
-  id->icon_id = 0;
-  id->newid = NULL; /* Needed because .blend may have been saved with crap value here... */
-  id->orig_id = NULL;
-  id->py_instance = NULL;
-
-  /* Initialize with provided tag. */
-  id->tag = tag;
-
-  if (ID_IS_LINKED(id)) {
-    id->library_weak_reference = NULL;
-  }
-  else {
-    BLO_read_data_address(reader, &id->library_weak_reference);
-  }
-
-  if (tag & LIB_TAG_ID_LINK_PLACEHOLDER) {
-    /* For placeholder we only need to set the tag and properly initialize generic ID fields above,
-     * no further data to read. */
-    return;
-  }
-
-  if (id->asset_data) {
-    BLO_read_data_address(reader, &id->asset_data);
-    BKE_asset_metadata_read(reader, id->asset_data);
-    /* Restore runtime asset type info. */
-    const IDTypeInfo *id_type = BKE_idtype_get_info_from_id(id);
-    id->asset_data->local_type_info = id_type->asset_type_info;
-  }
-
-  /* Link direct data of ID properties. */
-  if (id->properties) {
-    BLO_read_data_address(reader, &id->properties);
-    /* this case means the data was written incorrectly, it should not happen */
-    IDP_BlendDataRead(reader, &id->properties);
-  }
-
-  id->flag &= ~LIB_INDIRECT_WEAK_LINK;
-
-  /* NOTE: It is important to not clear the recalc flags for undo/redo.
-   * Preserving recalc flags on redo/undo is the only way to make dependency graph detect
-   * that animation is to be evaluated on undo/redo. If this is not enforced by the recalc
-   * flags dependency graph does not do animation update to avoid loss of unkeyed changes.,
-   * which conflicts with undo/redo of changes to animation data itself.
-   *
-   * But for regular file load we clear the flag, since the flags might have been changed since
-   * the version the file has been saved with. */
-  if (!BLO_read_data_is_undo(reader)) {
-    id->recalc = 0;
-    id->recalc_after_undo_push = 0;
-  }
-  else if ((reader->fd->skip_flags & BLO_READ_SKIP_UNDO_OLD_MAIN) == 0) {
-    id->recalc = direct_link_id_restore_recalc(reader->fd, id, id_old, false);
-    id->recalc_after_undo_push = 0;
-  }
-
-  /* Link direct data of overrides. */
-  if (id->override_library) {
-    BLO_read_data_address(reader, &id->override_library);
-    /* Work around file corruption on writing, see T86853. */
-    if (id->override_library != NULL) {
-      BLO_read_list_cb(
-          reader, &id->override_library->properties, direct_link_id_override_property_cb);
-      id->override_library->runtime = NULL;
-    }
-  }
-
-  DrawDataList *drawdata = DRW_drawdatalist_from_id(id);
-  if (drawdata) {
-    BLI_listbase_clear((ListBase *)drawdata);
-  }
-
-  /* Handle 'private IDs'. */
-  direct_link_id_embedded_id(reader, current_library, id, id_old);
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Read Animation (legacy for version patching)
- * \{ */
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Read ID: Shape Keys
- * \{ */
-
-void blo_do_versions_key_uidgen(Key *key)
-{
-  key->uidgen = 1;
-  LISTBASE_FOREACH (KeyBlock *, block, &key->block) {
-    block->uid = key->uidgen++;
-  }
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Read ID: Scene
- * \{ */
-
-#ifdef USE_SETSCENE_CHECK
-/**
- * A version of #BKE_scene_validate_setscene with special checks for linked libs.
- */
-static bool scene_validate_setscene__liblink(Scene *sce, const int totscene)
-{
-  Scene *sce_iter;
-  int a;
-
-  if (sce->set == NULL) {
-    return true;
-  }
-
-  for (a = 0, sce_iter = sce; sce_iter->set; sce_iter = sce_iter->set, a++) {
-    /* This runs per library (before each libraries #Main has been joined),
-     * so we can't step into other libraries since `totscene` is only for this library.
-     *
-     * Also, other libraries may not have been linked yet,
-     * while we could check #LIB_TAG_NEED_LINK the library pointer check is sufficient. */
-    if (sce->id.lib != sce_iter->id.lib) {
-      return true;
-    }
-    if (sce_iter->flag & SCE_READFILE_LIBLINK_NEED_SETSCENE_CHECK) {
-      return true;
-    }
-
-    if (a > totscene) {
-      sce->set = NULL;
-      return false;
-    }
-  }
-
-  return true;
-}
-#endif
-
-static void lib_link_scenes_check_set(Main *bmain)
-{
-#ifdef USE_SETSCENE_CHECK
-  const int totscene = BLI_listbase_count(&bmain->scenes);
-  LISTBASE_FOREACH (Scene *, sce, &bmain->scenes) {
-    if (sce->flag & SCE_READFILE_LIBLINK_NEED_SETSCENE_CHECK) {
-      sce->flag &= ~SCE_READFILE_LIBLINK_NEED_SETSCENE_CHECK;
-      if (!scene_validate_setscene__liblink(sce, totscene)) {
-        CLOG_WARN(&LOG, "Found cyclic background scene when linking %s", sce->id.name + 2);
-      }
-    }
-  }
-#else
-  UNUSED_VARS(bmain, totscene);
-#endif
-}
-
-#undef USE_SETSCENE_CHECK
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Read ID: Screen
- * \{ */
-
-/* how to handle user count on pointer restore */
-typedef enum ePointerUserMode {
-  USER_IGNORE = 0, /* ignore user count */
-  USER_REAL = 1,   /* ensure at least one real user (fake user ignored) */
-} ePointerUserMode;
-
-static void restore_pointer_user(ID *id, ID *newid, ePointerUserMode user)
-{
-  BLI_assert(STREQ(newid->name + 2, id->name + 2));
-  BLI_assert(newid->lib == id->lib);
-  UNUSED_VARS_NDEBUG(id);
-
-  if (user == USER_REAL) {
-    id_us_ensure_real(newid);
-  }
-}
-
-#ifndef USE_GHASH_RESTORE_POINTER
-/**
- * A version of #restore_pointer_by_name that performs a full search (slow!).
- * Use only for limited lookups, when the overhead of
- * creating a #IDNameLib_Map for a single lookup isn't worthwhile.
- */
-static void *restore_pointer_by_name_main(Main *mainp, ID *id, ePointerUserMode user)
-{
-  if (id) {
-    ListBase *lb = which_libbase(mainp, GS(id->name));
-    if (lb) { /* there's still risk of checking corrupt mem (freed Ids in oops) */
-      ID *idn = lb->first;
-      for (; idn; idn = idn->next) {
-        if (STREQ(idn->name + 2, id->name + 2)) {
-          if (idn->lib == id->lib) {
-            restore_pointer_user(id, idn, user);
-            break;
-          }
-        }
-      }
-      return idn;
-    }
-  }
-  return NULL;
-}
-#endif
-
-/**
- * Only for undo files, or to restore a screen after reading without UI...
- *
- * \param user:
- * - USER_IGNORE: no user-count change.
- * - USER_REAL: ensure a real user (even if a fake one is set).
- * \param id_map: lookup table, use when performing many lookups.
- * this could be made an optional argument (falling back to a full lookup),
- * however at the moment it's always available.
- */
-static void *restore_pointer_by_name(struct IDNameLib_Map *id_map, ID *id, ePointerUserMode user)
-{
-#ifdef USE_GHASH_RESTORE_POINTER
-  if (id) {
-    /* use fast lookup when available */
-    ID *idn = BKE_main_idmap_lookup_id(id_map, id);
-    if (idn) {
-      restore_pointer_user(id, idn, user);
-    }
-    return idn;
-  }
-  return NULL;
-#else
-  Main *mainp = BKE_main_idmap_main_get(id_map);
-  return restore_pointer_by_name_main(mainp, id, user);
-#endif
-}
-
-static void lib_link_seq_clipboard_pt_restore(ID *id, struct IDNameLib_Map *id_map)
-{
-  if (id) {
-    /* clipboard must ensure this */
-    BLI_assert(id->newid != NULL);
-    id->newid = restore_pointer_by_name(id_map, id->newid, USER_REAL);
-  }
-}
-static bool lib_link_seq_clipboard_cb(Sequence *seq, void *arg_pt)
-{
-  struct IDNameLib_Map *id_map = arg_pt;
-
-  lib_link_seq_clipboard_pt_restore((ID *)seq->scene, id_map);
-  lib_link_seq_clipboard_pt_restore((ID *)seq->scene_camera, id_map);
-  lib_link_seq_clipboard_pt_restore((ID *)seq->clip, id_map);
-  lib_link_seq_clipboard_pt_restore((ID *)seq->mask, id_map);
-  lib_link_seq_clipboard_pt_restore((ID *)seq->sound, id_map);
-  return true;
-}
-
-static void lib_link_clipboard_restore(struct IDNameLib_Map *id_map)
-{
-  /* update IDs stored in sequencer clipboard */
-  SEQ_for_each_callback(&seqbase_clipboard, lib_link_seq_clipboard_cb, id_map);
-}
-
-static int lib_link_main_data_restore_cb(LibraryIDLinkCallbackData *cb_data)
-{
-  const int cb_flag = cb_data->cb_flag;
-  ID **id_pointer = cb_data->id_pointer;
-  if (cb_flag & IDWALK_CB_EMBEDDED || *id_pointer == NULL) {
-    return IDWALK_RET_NOP;
-  }
-
-  /* Special ugly case here, thanks again for those non-IDs IDs... */
-  /* We probably need to add more cases here (hint: nodetrees),
-   * but will wait for changes from D5559 to get in first. */
-  if (GS((*id_pointer)->name) == ID_GR) {
-    Collection *collection = (Collection *)*id_pointer;
-    if (collection->flag & COLLECTION_IS_MASTER) {
-      /* We should never reach that point anymore, since master collection private ID should be
-       * properly tagged with IDWALK_CB_EMBEDDED. */
-      BLI_assert_unreachable();
-      return IDWALK_RET_NOP;
-    }
-  }
-
-  struct IDNameLib_Map *id_map = cb_data->user_data;
-
-  /* NOTE: Handling of usercount here is really bad, defining its own system...
-   * Will have to be refactored at some point, but that is not top priority task for now.
-   * And all user-counts are properly recomputed at the end of the undo management code anyway. */
-  *id_pointer = restore_pointer_by_name(
-      id_map, *id_pointer, (cb_flag & IDWALK_CB_USER_ONE) ? USER_REAL : USER_IGNORE);
-
-  return IDWALK_RET_NOP;
-}
-
-static void lib_link_main_data_restore(struct IDNameLib_Map *id_map, Main *newmain)
-{
-  ID *id;
-  FOREACH_MAIN_ID_BEGIN (newmain, id) {
-    BKE_library_foreach_ID_link(newmain, id, lib_link_main_data_restore_cb, id_map, IDWALK_NOP);
-  }
-  FOREACH_MAIN_ID_END;
-}
-
-static void lib_link_wm_xr_data_restore(struct IDNameLib_Map *id_map, wmXrData *xr_data)
-{
-  xr_data->session_settings.base_pose_object = restore_pointer_by_name(
-      id_map, (ID *)xr_data->session_settings.base_pose_object, USER_REAL);
-}
-
-static void lib_link_window_scene_data_restore(wmWindow *win, Scene *scene, ViewLayer *view_layer)
-{
-  bScreen *screen = BKE_workspace_active_screen_get(win->workspace_hook);
-
-  LISTBASE_FOREACH (ScrArea *, area, &screen->areabase) {
-    LISTBASE_FOREACH (SpaceLink *, sl, &area->spacedata) {
-      if (sl->spacetype == SPACE_VIEW3D) {
-        View3D *v3d = (View3D *)sl;
-
-        if (v3d->camera == NULL || v3d->scenelock) {
-          v3d->camera = scene->camera;
-        }
-
-        if (v3d->localvd) {
-          Base *base = NULL;
-
-          v3d->localvd->camera = scene->camera;
-
-          /* Local-view can become invalid during undo/redo steps,
-           * so we exit it when no could be found. */
-          for (base = view_layer->object_bases.first; base; base = base->next) {
-            if (base->local_view_bits & v3d->local_view_uuid) {
-              break;
-            }
-          }
-          if (base == NULL) {
-            MEM_freeN(v3d->localvd);
-            v3d->localvd = NULL;
-            v3d->local_view_uuid = 0;
-
-            /* Region-base storage is different depending if the space is active. */
-            ListBase *regionbase = (sl == area->spacedata.first) ? &area->regionbase :
-                                                                   &sl->regionbase;
-            LISTBASE_FOREACH (ARegion *, region, regionbase) {
-              if (region->regiontype == RGN_TYPE_WINDOW) {
-                RegionView3D *rv3d = region->regiondata;
-                if (rv3d->localvd) {
-                  MEM_freeN(rv3d->localvd);
-                  rv3d->localvd = NULL;
-                }
-              }
-            }
-          }
-        }
-      }
-    }
-  }
-}
-
-static void lib_link_workspace_layout_restore(struct IDNameLib_Map *id_map,
-                                              Main *newmain,
-                                              WorkSpaceLayout *layout)
-{
-  bScreen *screen = BKE_workspace_layout_screen_get(layout);
-
-  /* avoid conflicts with 2.8x branch */
-  {
-    LISTBASE_FOREACH (ScrArea *, area, &screen->areabase) {
-      LISTBASE_FOREACH (SpaceLink *, sl, &area->spacedata) {
-        if (sl->spacetype == SPACE_VIEW3D) {
-          View3D *v3d = (View3D *)sl;
-
-          v3d->camera = restore_pointer_by_name(id_map, (ID *)v3d->camera, USER_REAL);
-          v3d->ob_center = restore_pointer_by_name(id_map, (ID *)v3d->ob_center, USER_REAL);
-        }
-        else if (sl->spacetype == SPACE_GRAPH) {
-          SpaceGraph *sipo = (SpaceGraph *)sl;
-          bDopeSheet *ads = sipo->ads;
-
-          if (ads) {
-            ads->source = restore_pointer_by_name(id_map, (ID *)ads->source, USER_REAL);
-
-            if (ads->filter_grp) {
-              ads->filter_grp = restore_pointer_by_name(
-                  id_map, (ID *)ads->filter_grp, USER_IGNORE);
-            }
-          }
-
-          /* force recalc of list of channels (i.e. includes calculating F-Curve colors)
-           * thus preventing the "black curves" problem post-undo
-           */
-          sipo->runtime.flag |= SIPO_RUNTIME_FLAG_NEED_CHAN_SYNC_COLOR;
-        }
-        else if (sl->spacetype == SPACE_PROPERTIES) {
-          SpaceProperties *sbuts = (SpaceProperties *)sl;
-          sbuts->pinid = restore_pointer_by_name(id_map, sbuts->pinid, USER_IGNORE);
-          if (sbuts->pinid == NULL) {
-            sbuts->flag &= ~SB_PIN_CONTEXT;
-          }
-
-          /* TODO: restore path pointers: T40046
-           * (complicated because this contains data pointers too, not just ID). */
-          MEM_SAFE_FREE(sbuts->path);
-        }
-        else if (sl->spacetype == SPACE_FILE) {
-          SpaceFile *sfile = (SpaceFile *)sl;
-          sfile->op = NULL;
-          sfile->tags = FILE_TAG_REBUILD_MAIN_FILES;
-        }
-        else if (sl->spacetype == SPACE_ACTION) {
-          SpaceAction *saction = (SpaceAction *)sl;
-
-          saction->action = restore_pointer_by_name(id_map, (ID *)saction->action, USER_REAL);
-          saction->ads.source = restore_pointer_by_name(
-              id_map, (ID *)saction->ads.source, USER_REAL);
-
-          if (saction->ads.filter_grp) {
-            saction->ads.filter_grp = restore_pointer_by_name(
-                id_map, (ID *)saction->ads.filter_grp, USER_IGNORE);
-          }
-
-          /* force recalc of list of channels, potentially updating the active action
-           * while we're at it (as it can only be updated that way) T28962.
-           */
-          saction->runtime.flag |= SACTION_RUNTIME_FLAG_NEED_CHAN_SYNC;
-        }
-        else if (sl->spacetype == SPACE_IMAGE) {
-          SpaceImage *sima = (SpaceImage *)sl;
-
-          sima->image = restore_pointer_by_name(id_map, (ID *)sima->image, USER_REAL);
-
-          /* this will be freed, not worth attempting to find same scene,
-           * since it gets initialized later */
-          sima->iuser.scene = NULL;
-
-#if 0
-          /* Those are allocated and freed by space code, no need to handle them here. */
-          MEM_SAFE_FREE(sima->scopes.waveform_1);
-          MEM_SAFE_FREE(sima->scopes.waveform_2);
-          MEM_SAFE_FREE(sima->scopes.waveform_3);
-          MEM_SAFE_FREE(sima->scopes.vecscope);
-#endif
-          sima->scopes.ok = 0;
-
-          /* NOTE: pre-2.5, this was local data not lib data, but now we need this as lib data
-           * so assume that here we're doing for undo only...
-           */
-          sima->gpd = restore_pointer_by_name(id_map, (ID *)sima->gpd, USER_REAL);
-          sima->mask_info.mask = restore_pointer_by_name(
-              id_map, (ID *)sima->mask_info.mask, USER_REAL);
-        }
-        else if (sl->spacetype == SPACE_SEQ) {
-          SpaceSeq *sseq = (SpaceSeq *)sl;
-
-          /* NOTE: pre-2.5, this was local data not lib data, but now we need this as lib data
-           * so assume that here we're doing for undo only...
-           */
-          sseq->gpd = restore_pointer_by_name(id_map, (ID *)sseq->gpd, USER_REAL);
-        }
-        else if (sl->spacetype == SPACE_NLA) {
-          SpaceNla *snla = (SpaceNla *)sl;
-          bDopeSheet *ads = snla->ads;
-
-          if (ads) {
-            ads->source = restore_pointer_by_name(id_map, (ID *)ads->source, USER_REAL);
-
-            if (ads->filter_grp) {
-              ads->filter_grp = restore_pointer_by_name(
-                  id_map, (ID *)ads->filter_grp, USER_IGNORE);
-            }
-          }
-        }
-        else if (sl->spacetype == SPACE_TEXT) {
-          SpaceText *st = (SpaceText *)sl;
-
-          st->text = restore_pointer_by_name(id_map, (ID *)st->text, USER_IGNORE);
-          if (st->text == NULL) {
-            st->text = newmain->texts.first;
-          }
-        }
-        else if (sl->spacetype == SPACE_SCRIPT) {
-          SpaceScript *scpt = (SpaceScript *)sl;
-
-          scpt->script = restore_pointer_by_name(id_map, (ID *)scpt->script, USER_REAL);
-
-          // screen->script = NULL; /* 2.45 set to null, better re-run the script. */
-          if (scpt->script) {
-            SCRIPT_SET_NULL(scpt->script);
-          }
-        }
-        else if (sl->spacetype == SPACE_OUTLINER) {
-          SpaceOutliner *space_outliner = (SpaceOutliner *)sl;
-
-          space_outliner->search_tse.id = restore_pointer_by_name(
-              id_map, space_outliner->search_tse.id, USER_IGNORE);
-
-          if (space_outliner->treestore) {
-            TreeStoreElem *tselem;
-            BLI_mempool_iter iter;
-
-            BLI_mempool_iternew(space_outliner->treestore, &iter);
-            while ((tselem = BLI_mempool_iterstep(&iter))) {
-              /* Do not try to restore pointers to drivers/sequence/etc.,
-               * can crash in undo case! */
-              if (TSE_IS_REAL_ID(tselem)) {
-                tselem->id = restore_pointer_by_name(id_map, tselem->id, USER_IGNORE);
-              }
-              else {
-                tselem->id = NULL;
-              }
-            }
-            /* rebuild hash table, because it depends on ids too */
-            space_outliner->storeflag |= SO_TREESTORE_REBUILD;
-          }
-        }
-        else if (sl->spacetype == SPACE_NODE) {
-          SpaceNode *snode = (SpaceNode *)sl;
-          bNodeTreePath *path, *path_next;
-          bNodeTree *ntree;
-
-          /* node tree can be stored locally in id too, link this first */
-          snode->id = restore_pointer_by_name(id_map, snode->id, USER_REAL);
-          snode->from = restore_pointer_by_name(id_map, snode->from, USER_IGNORE);
-
-          ntree = snode->id ? ntreeFromID(snode->id) : NULL;
-          snode->nodetree = ntree ?
-                                ntree :
-                                restore_pointer_by_name(id_map, (ID *)snode->nodetree, USER_REAL);
-
-          for (path = snode->treepath.first; path; path = path->next) {
-            if (path == snode->treepath.first) {
-              /* first nodetree in path is same as snode->nodetree */
-              path->nodetree = snode->nodetree;
-            }
-            else {
-              path->nodetree = restore_pointer_by_name(id_map, (ID *)path->nodetree, USER_REAL);
-            }
-
-            if (!path->nodetree) {
-              break;
-            }
-          }
-
-          /* remaining path entries are invalid, remove */
-          for (; path; path = path_next) {
-            path_next = path->next;
-
-            BLI_remlink(&snode->treepath, path);
-            MEM_freeN(path);
-          }
-
-          /* edittree is just the last in the path,
-           * set this directly since the path may have been shortened above */
-          if (snode->treepath.last) {
-            path = snode->treepath.last;
-            snode->edittree = path->nodetree;
-          }
-          else {
-            snode->edittree = NULL;
-          }
-        }
-        else if (sl->spacetype == SPACE_CLIP) {
-          SpaceClip *sclip = (SpaceClip *)sl;
-
-          sclip->clip = restore_pointer_by_name(id_map, (ID *)sclip->clip, USER_REAL);
-          sclip->mask_info.mask = restore_pointer_by_name(
-              id_map, (ID *)sclip->mask_info.mask, USER_REAL);
-
-          sclip->scopes.ok = 0;
-        }
-        else if (sl->spacetype == SPACE_SPREADSHEET) {
-          SpaceSpreadsheet *sspreadsheet = (SpaceSpreadsheet *)sl;
-
-          LISTBASE_FOREACH (SpreadsheetContext *, context, &sspreadsheet->context_path) {
-            if (context->type == SPREADSHEET_CONTEXT_OBJECT) {
-              SpreadsheetContextObject *object_context = (SpreadsheetContextObject *)context;
-              object_context->object = restore_pointer_by_name(
-                  id_map, (ID *)object_context->object, USER_IGNORE);
-            }
-          }
-        }
-      }
-    }
-  }
-}
-
-void blo_lib_link_restore(Main *oldmain,
-                          Main *newmain,
-                          wmWindowManager *curwm,
-                          Scene *curscene,
-                          ViewLayer *cur_view_layer)
-{
-  struct IDNameLib_Map *id_map = BKE_main_idmap_create(
-      newmain, true, oldmain, MAIN_IDMAP_TYPE_NAME);
-
-  LISTBASE_FOREACH (WorkSpace *, workspace, &newmain->workspaces) {
-    LISTBASE_FOREACH (WorkSpaceLayout *, layout, &workspace->layouts) {
-      lib_link_workspace_layout_restore(id_map, newmain, layout);
-    }
-    workspace->pin_scene = restore_pointer_by_name(
-        id_map, (ID *)workspace->pin_scene, USER_IGNORE);
-  }
-
-  LISTBASE_FOREACH (wmWindow *, win, &curwm->windows) {
-    WorkSpace *workspace = BKE_workspace_active_get(win->workspace_hook);
-    ID *workspace_id = (ID *)workspace;
-    Scene *oldscene = win->scene;
-
-    workspace = restore_pointer_by_name(id_map, workspace_id, USER_REAL);
-    BKE_workspace_active_set(win->workspace_hook, workspace);
-    win->scene = restore_pointer_by_name(id_map, (ID *)win->scene, USER_REAL);
-    if (win->scene == NULL) {
-      win->scene = curscene;
-    }
-    win->unpinned_scene = restore_pointer_by_name(id_map, (ID *)win->unpinned_scene, USER_IGNORE);
-    if (BKE_view_layer_find(win->scene, win->view_layer_name) == NULL) {
-      STRNCPY(win->view_layer_name, cur_view_layer->name);
-    }
-    BKE_workspace_active_set(win->workspace_hook, workspace);
-
-    /* keep cursor location through undo */
-    memcpy(&win->scene->cursor, &oldscene->cursor, sizeof(win->scene->cursor));
-
-    /* NOTE: even though that function seems to redo part of what is done by
-     * `lib_link_workspace_layout_restore()` above, it seems to have a slightly different scope:
-     * while the former updates the whole UI pointers from Main db (going over all layouts of
-     * all workspaces), that one only focuses one current active screen, takes care of
-     * potential local view, and needs window's scene pointer to be final... */
-    lib_link_window_scene_data_restore(win, win->scene, cur_view_layer);
-
-    BLI_assert(win->screen == NULL);
-  }
-
-  lib_link_wm_xr_data_restore(id_map, &curwm->xr);
-
-  /* Restore all ID pointers in Main database itself
-   * (especially IDProperties might point to some word-space of other 'weirdly unchanged' ID
-   * pointers, see T69146).
-   * Note that this will re-apply again a few pointers in workspaces or so,
-   * but since we are remapping final ones already set above,
-   * that is just some minor harmless double-processing. */
-  lib_link_main_data_restore(id_map, newmain);
-
-  /* update IDs stored in all possible clipboards */
-  lib_link_clipboard_restore(id_map);
-
-  BKE_main_idmap_destroy(id_map);
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Read ID: Library
- * \{ */
-
-static void direct_link_library(FileData *fd, Library *lib, Main *main)
-{
-  Main *newmain;
-
-  /* check if the library was already read */
-  for (newmain = fd->mainlist->first; newmain; newmain = newmain->next) {
-    if (newmain->curlib) {
-      if (BLI_path_cmp(newmain->curlib->filepath_abs, lib->filepath_abs) == 0) {
-        BLO_reportf_wrap(fd->reports,
-                         RPT_WARNING,
-                         TIP_("Library '%s', '%s' had multiple instances, save and reload!"),
-                         lib->filepath,
-                         lib->filepath_abs);
-
-        change_link_placeholder_to_real_ID_pointer(fd->mainlist, fd, lib, newmain->curlib);
-        /*              change_link_placeholder_to_real_ID_pointer_fd(fd, lib, newmain->curlib); */
-
-        BLI_remlink(&main->libraries, lib);
-        MEM_freeN(lib);
-
-        /* Now, since Blender always expect **latest** Main pointer from fd->mainlist
-         * to be the active library Main pointer,
-         * where to add all non-library data-blocks found in file next, we have to switch that
-         * 'dupli' found Main to latest position in the list!
-         * Otherwise, you get weird disappearing linked data on a rather inconsistent basis.
-         * See also T53977 for reproducible case. */
-        BLI_remlink(fd->mainlist, newmain);
-        BLI_addtail(fd->mainlist, newmain);
-
-        return;
-      }
-    }
-  }
-
-  /* Make sure we have full path in lib->filepath_abs */
-  BLI_strncpy(lib->filepath_abs, lib->filepath, sizeof(lib->filepath));
-  BLI_path_normalize(fd->relabase, lib->filepath_abs);
-
-  //  printf("direct_link_library: filepath %s\n", lib->filepath);
-  //  printf("direct_link_library: filepath_abs %s\n", lib->filepath_abs);
-
-  BlendDataReader reader = {fd};
-  BKE_packedfile_blend_read(&reader, &lib->packedfile);
-
-  /* new main */
-  newmain = BKE_main_new();
-  BLI_addtail(fd->mainlist, newmain);
-  newmain->curlib = lib;
-
-  lib->parent = NULL;
-
-  id_us_ensure_real(&lib->id);
-}
-
-static void lib_link_library(BlendLibReader *UNUSED(reader), Library *UNUSED(lib))
-{
-}
-
-/* Always call this once you have loaded new library data to set the relative paths correctly
- * in relation to the blend file. */
-static void fix_relpaths_library(const char *basepath, Main *main)
-{
-  /* #BLO_read_from_memory uses a blank file-path. */
-  if (basepath == NULL || basepath[0] == '\0') {
-    LISTBASE_FOREACH (Library *, lib, &main->libraries) {
-      /* when loading a linked lib into a file which has not been saved,
-       * there is nothing we can be relative to, so instead we need to make
-       * it absolute. This can happen when appending an object with a relative
-       * link into an unsaved blend file. See T27405.
-       * The remap relative option will make it relative again on save - campbell */
-      if (BLI_path_is_rel(lib->filepath)) {
-        BLI_strncpy(lib->filepath, lib->filepath_abs, sizeof(lib->filepath));
-      }
-    }
-  }
-  else {
-    LISTBASE_FOREACH (Library *, lib, &main->libraries) {
-      /* Libraries store both relative and abs paths, recreate relative paths,
-       * relative to the blend file since indirectly linked libs will be
-       * relative to their direct linked library. */
-      if (BLI_path_is_rel(lib->filepath)) { /* if this is relative to begin with? */
-        BLI_strncpy(lib->filepath, lib->filepath_abs, sizeof(lib->filepath));
-        BLI_path_rel(lib->filepath, basepath);
-      }
-    }
-  }
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Read Library Data Block
- * \{ */
-
-static ID *create_placeholder(Main *mainvar, const short idcode, const char *idname, const int tag)
-{
-  ListBase *lb = which_libbase(mainvar, idcode);
-  ID *ph_id = BKE_libblock_alloc_notest(idcode);
-
-  *((short *)ph_id->name) = idcode;
-  BLI_strncpy(ph_id->name + 2, idname, sizeof(ph_id->name) - 2);
-  BKE_libblock_init_empty(ph_id);
-  ph_id->lib = mainvar->curlib;
-  ph_id->tag = tag | LIB_TAG_MISSING;
-  ph_id->us = ID_FAKE_USERS(ph_id);
-  ph_id->icon_id = 0;
-
-  BLI_addtail(lb, ph_id);
-  id_sort_by_name(lb, ph_id, NULL);
-
-  if (mainvar->id_map != NULL) {
-    BKE_main_idmap_insert_id(mainvar->id_map, ph_id);
-  }
-
-  if ((tag & LIB_TAG_TEMP_MAIN) == 0) {
-    BKE_lib_libblock_session_uuid_ensure(ph_id);
-  }
-
-  return ph_id;
-}
-
-static void placeholders_ensure_valid(Main *bmain)
-{
-  /* Placeholder ObData IDs won't have any material, we have to update their objects for that,
-   * otherwise the inconsistency between both will lead to crashes (especially in Eevee?). */
-  LISTBASE_FOREACH (Object *, ob, &bmain->objects) {
-    ID *obdata = ob->data;
-    if (obdata != NULL && obdata->tag & LIB_TAG_MISSING) {
-      BKE_object_materials_test(bmain, ob, obdata);
-    }
-  }
-}
-
-static const char *dataname(short id_code)
-{
-  switch ((ID_Type)id_code) {
-    case ID_OB:
-      return "Data from OB";
-    case ID_ME:
-      return "Data from ME";
-    case ID_IP:
-      return "Data from IP";
-    case ID_SCE:
-      return "Data from SCE";
-    case ID_MA:
-      return "Data from MA";
-    case ID_TE:
-      return "Data from TE";
-    case ID_CU_LEGACY:
-      return "Data from CU";
-    case ID_GR:
-      return "Data from GR";
-    case ID_AR:
-      return "Data from AR";
-    case ID_AC:
-      return "Data from AC";
-    case ID_LI:
-      return "Data from LI";
-    case ID_MB:
-      return "Data from MB";
-    case ID_IM:
-      return "Data from IM";
-    case ID_LT:
-      return "Data from LT";
-    case ID_LA:
-      return "Data from LA";
-    case ID_CA:
-      return "Data from CA";
-    case ID_KE:
-      return "Data from KE";
-    case ID_WO:
-      return "Data from WO";
-    case ID_SCR:
-      return "Data from SCR";
-    case ID_VF:
-      return "Data from VF";
-    case ID_TXT:
-      return "Data from TXT";
-    case ID_SPK:
-      return "Data from SPK";
-    case ID_LP:
-      return "Data from LP";
-    case ID_SO:
-      return "Data from SO";
-    case ID_NT:
-      return "Data from NT";
-    case ID_BR:
-      return "Data from BR";
-    case ID_PA:
-      return "Data from PA";
-    case ID_PAL:
-      return "Data from PAL";
-    case ID_PC:
-      return "Data from PCRV";
-    case ID_GD:
-      return "Data from GD";
-    case ID_WM:
-      return "Data from WM";
-    case ID_MC:
-      return "Data from MC";
-    case ID_MSK:
-      return "Data from MSK";
-    case ID_LS:
-      return "Data from LS";
-    case ID_CF:
-      return "Data from CF";
-    case ID_WS:
-      return "Data from WS";
-    case ID_CV:
-      return "Data from HA";
-    case ID_PT:
-      return "Data from PT";
-    case ID_VO:
-      return "Data from VO";
-    case ID_SIM:
-      return "Data from SIM";
-  }
-  return "Data from Lib Block";
-}
-
-static bool direct_link_id(FileData *fd, Main *main, const int tag, ID *id, ID *id_old)
-{
-  BlendDataReader reader = {fd};
-
-  /* Read part of datablock that is common between real and embedded datablocks. */
-  direct_link_id_common(&reader, main->curlib, id, id_old, tag);
-
-  if (tag & LIB_TAG_ID_LINK_PLACEHOLDER) {
-    /* For placeholder we only need to set the tag, no further data to read. */
-    id->tag = tag;
-    return true;
-  }
-
-  const IDTypeInfo *id_type = BKE_idtype_get_info_from_id(id);
-  if (id_type->blend_read_data != NULL) {
-    id_type->blend_read_data(&reader, id);
-  }
-
-  /* XXX Very weakly handled currently, see comment in read_libblock() before trying to
-   * use it for anything new. */
-  bool success = true;
-
-  switch (GS(id->name)) {
-    case ID_SCR:
-      success = BKE_screen_blend_read_data(&reader, (bScreen *)id);
-      break;
-    case ID_LI:
-      direct_link_library(fd, (Library *)id, main);
-      break;
-    default:
-      /* Do nothing. Handled by IDTypeInfo callback. */
-      break;
-  }
-
-  /* try to restore (when undoing) or clear ID's cache pointers. */
-  if (id_type->foreach_cache != NULL) {
-    BKE_idtype_id_foreach_cache(
-        id, blo_cache_storage_entry_restore_in_new, reader.fd->cache_storage);
-  }
-
-  return success;
-}
-
-/* Read all data associated with a datablock into datamap. */
-static BHead *read_data_into_datamap(FileData *fd, BHead *bhead, const char *allocname)
-{
-  bhead = blo_bhead_next(fd, bhead);
-
-  while (bhead && bhead->code == DATA) {
-    /* The code below is useful for debugging leaks in data read from the blend file.
-     * Without this the messages only tell us what ID-type the memory came from,
-     * eg: `Data from OB len 64`, see #dataname.
-     * With the code below we get the struct-name to help tracking down the leak.
-     * This is kept disabled as the #malloc for the text always leaks memory. */
-#if 0
-    {
-      const short *sp = fd->filesdna->structs[bhead->SDNAnr];
-      allocname = fd->filesdna->types[sp[0]];
-      size_t allocname_size = strlen(allocname) + 1;
-      char *allocname_buf = malloc(allocname_size);
-      memcpy(allocname_buf, allocname, allocname_size);
-      allocname = allocname_buf;
-    }
-#endif
-
-    void *data = read_struct(fd, bhead, allocname);
-    if (data) {
-      oldnewmap_insert(fd->datamap, bhead->old, data, 0);
-    }
-
-    bhead = blo_bhead_next(fd, bhead);
-  }
-
-  return bhead;
-}
-
-/* Verify if the datablock and all associated data is identical. */
-static bool read_libblock_is_identical(FileData *fd, BHead *bhead)
-{
-  /* Test ID itself. */
-  if (bhead->len && !BHEADN_FROM_BHEAD(bhead)->is_memchunk_identical) {
-    return false;
-  }
-
-  /* Test any other data that is part of ID (logic must match read_data_into_datamap). */
-  bhead = blo_bhead_next(fd, bhead);
-
-  while (bhead && bhead->code == DATA) {
-    if (bhead->len && !BHEADN_FROM_BHEAD(bhead)->is_memchunk_identical) {
-      return false;
-    }
-
-    bhead = blo_bhead_next(fd, bhead);
-  }
-
-  return true;
-}
-
-/* For undo, restore matching library datablock from the old main. */
-static bool read_libblock_undo_restore_library(FileData *fd, Main *main, const ID *id)
-{
-  /* In undo case, most libs and linked data should be kept as is from previous state
-   * (see BLO_read_from_memfile).
-   * However, some needed by the snapshot being read may have been removed in previous one,
-   * and would go missing.
-   * This leads e.g. to disappearing objects in some undo/redo case, see T34446.
-   * That means we have to carefully check whether current lib or
-   * libdata already exits in old main, if it does we merely copy it over into new main area,
-   * otherwise we have to do a full read of that bhead... */
-  CLOG_INFO(&LOG_UNDO, 2, "UNDO: restore library %s", id->name);
-
-  Main *libmain = fd->old_mainlist->first;
-  /* Skip oldmain itself... */
-  for (libmain = libmain->next; libmain; libmain = libmain->next) {
-    if (libmain->curlib && STREQ(id->name, libmain->curlib->id.name)) {
-      Main *oldmain = fd->old_mainlist->first;
-      CLOG_INFO(&LOG_UNDO,
-                2,
-                "    compare with %s -> match",
-                libmain->curlib ? libmain->curlib->id.name : "");
-      /* In case of a library, we need to re-add its main to fd->mainlist,
-       * because if we have later a missing ID_LINK_PLACEHOLDER,
-       * we need to get the correct lib it is linked to!
-       * Order is crucial, we cannot bulk-add it in BLO_read_from_memfile()
-       * like it used to be. */
-      BLI_remlink(fd->old_mainlist, libmain);
-      BLI_remlink_safe(&oldmain->libraries, libmain->curlib);
-      BLI_addtail(fd->mainlist, libmain);
-      BLI_addtail(&main->libraries, libmain->curlib);
-      return true;
-    }
-    CLOG_INFO(&LOG_UNDO,
-              2,
-              "    compare with %s -> NO match",
-              libmain->curlib ? libmain->curlib->id.name : "");
-  }
-
-  return false;
-}
-
-/* For undo, restore existing linked datablock from the old main. */
-static bool read_libblock_undo_restore_linked(FileData *fd, Main *main, const ID *id, BHead *bhead)
-{
-  CLOG_INFO(&LOG_UNDO, 2, "UNDO: restore linked datablock %s", id->name);
-
-  ID *id_old = BKE_libblock_find_name(main, GS(id->name), id->name + 2);
-  if (id_old != NULL) {
-    CLOG_INFO(&LOG_UNDO,
-              2,
-              "    from %s (%s): found",
-              main->curlib ? main->curlib->id.name : "",
-              main->curlib ? main->curlib->filepath : "");
-    /* Even though we found our linked ID, there is no guarantee its address
-     * is still the same. */
-    if (id_old != bhead->old) {
-      oldnewmap_insert(fd->libmap, bhead->old, id_old, GS(id_old->name));
-    }
-
-    /* No need to do anything else for ID_LINK_PLACEHOLDER, it's assumed
-     * already present in its lib's main. */
-    return true;
-  }
-
-  CLOG_INFO(&LOG_UNDO,
-            2,
-            "    from %s (%s): NOT found",
-            main->curlib ? main->curlib->id.name : "",
-            main->curlib ? main->curlib->filepath : "");
-  return false;
-}
-
-/* For undo, restore unchanged datablock from old main. */
-static void read_libblock_undo_restore_identical(
-    FileData *fd, Main *main, const ID *UNUSED(id), ID *id_old, const int tag)
-{
-  BLI_assert((fd->skip_flags & BLO_READ_SKIP_UNDO_OLD_MAIN) == 0);
-  BLI_assert(id_old != NULL);
-
-  /* Some tags need to be preserved here. */
-  id_old->tag = tag | (id_old->tag & LIB_TAG_EXTRAUSER);
-  id_old->lib = main->curlib;
-  id_old->us = ID_FAKE_USERS(id_old);
-  /* Do not reset id->icon_id here, memory allocated for it remains valid. */
-  /* Needed because .blend may have been saved with crap value here... */
-  id_old->newid = NULL;
-  id_old->orig_id = NULL;
-
-  const short idcode = GS(id_old->name);
-  Main *old_bmain = fd->old_mainlist->first;
-  ListBase *old_lb = which_libbase(old_bmain, idcode);
-  ListBase *new_lb = which_libbase(main, idcode);
-  BLI_remlink(old_lb, id_old);
-  BLI_addtail(new_lb, id_old);
-
-  /* Recalc flags, mostly these just remain as they are. */
-  id_old->recalc |= direct_link_id_restore_recalc_exceptions(id_old);
-  id_old->recalc_after_undo_push = 0;
-
-  if (GS(id_old->name) == ID_OB) {
-    Object *ob = (Object *)id_old;
-    /* For undo we stay in object mode during undo presses, so keep editmode disabled for re-used
-     * data-blocks too. */
-    ob->mode &= ~OB_MODE_EDIT;
-  }
-}
-
-/* For undo, store changed datablock at old address. */
-static void read_libblock_undo_restore_at_old_address(FileData *fd, Main *main, ID *id, ID *id_old)
-{
-  /* During memfile undo, if an ID changed and we cannot directly re-use existing one from old
-   * bmain, we do a full read of the new id from the memfile, and then fully swap its content
-   * with the old id. This allows us to keep the same pointer even for modified data, which
-   * helps reducing further detected changes by the depsgraph (since unchanged IDs remain fully
-   * unchanged, even if they are using/pointing to a changed one). */
-  BLI_assert((fd->skip_flags & BLO_READ_SKIP_UNDO_OLD_MAIN) == 0);
-  BLI_assert(id_old != NULL);
-
-  const short idcode = GS(id->name);
-
-  Main *old_bmain = fd->old_mainlist->first;
-  ListBase *old_lb = which_libbase(old_bmain, idcode);
-  ListBase *new_lb = which_libbase(main, idcode);
-  BLI_remlink(old_lb, id_old);
-  BLI_remlink(new_lb, id);
-
-  /* We do not need any remapping from this call here, since no ID pointer is valid in the data
-   * currently (they are all pointing to old addresses, and need to go through `lib_link`
-   * process). So we can pass NULL for the Main pointer parameter. */
-  BKE_lib_id_swap_full(NULL, id, id_old);
-
-  /* Special temporary usage of this pointer, necessary for the `undo_preserve` call after
-   * lib-linking to restore some data that should never be affected by undo, e.g. the 3D cursor of
-   * #Scene. */
-  id_old->orig_id = id;
-
-  BLI_addtail(new_lb, id_old);
-  BLI_addtail(old_lb, id);
-}
-
-static bool read_libblock_undo_restore(
-    FileData *fd, Main *main, BHead *bhead, const int tag, ID **r_id_old)
-{
-  /* Get pointer to memory of new ID that we will be reading. */
-  const ID *id = peek_struct_undo(fd, bhead);
-  const short idcode = GS(id->name);
-
-  if (bhead->code == ID_LI) {
-    /* Restore library datablock. */
-    if (read_libblock_undo_restore_library(fd, main, id)) {
-      return true;
-    }
-  }
-  else if (bhead->code == ID_LINK_PLACEHOLDER) {
-    /* Restore linked datablock. */
-    if (read_libblock_undo_restore_linked(fd, main, id, bhead)) {
-      return true;
-    }
-  }
-  else if (ELEM(idcode, ID_WM, ID_SCR, ID_WS)) {
-    /* Skip reading any UI datablocks, existing ones are kept. We don't
-     * support pointers from other datablocks to UI datablocks so those
-     * we also don't put UI datablocks in fd->libmap. */
-    return true;
-  }
-
-  /* Restore local datablocks. */
-  ID *id_old = NULL;
-  const bool do_partial_undo = (fd->skip_flags & BLO_READ_SKIP_UNDO_OLD_MAIN) == 0;
-  if (do_partial_undo && (bhead->code != ID_LINK_PLACEHOLDER)) {
-    /* This code should only ever be reached for local data-blocks. */
-    BLI_assert(main->curlib == NULL);
-
-    /* Find the 'current' existing ID we want to reuse instead of the one we
-     * would read from the undo memfile. */
-    BLI_assert(fd->old_idmap != NULL);
-    id_old = BKE_main_idmap_lookup_uuid(fd->old_idmap, id->session_uuid);
-  }
-
-  if (id_old != NULL && read_libblock_is_identical(fd, bhead)) {
-    /* Local datablock was unchanged, restore from the old main. */
-    CLOG_INFO(&LOG_UNDO,
-              2,
-              "UNDO: read %s (uuid %u) -> keep identical datablock",
-              id->name,
-              id->session_uuid);
-
-    /* Do not add LIB_TAG_NEW here, this should not be needed/used in undo case anyway (as
-     * this is only for do_version-like code), but for sake of consistency, and also because
-     * it will tell us which ID is re-used from old Main, and which one is actually new. */
-    /* Also do not add LIB_TAG_NEED_LINK, those IDs will never be re-liblinked, hence that tag will
-     * never be cleared, leading to critical issue in link/append code. */
-    const int id_tag = tag | LIB_TAG_UNDO_OLD_ID_REUSED;
-    read_libblock_undo_restore_identical(fd, main, id, id_old, id_tag);
-
-    /* Insert into library map for lookup by newly read datablocks (with pointer value bhead->old).
-     * Note that existing datablocks in memory (which pointer value would be id_old) are not
-     * remapped anymore, so no need to store this info here. */
-    oldnewmap_insert(fd->libmap, bhead->old, id_old, bhead->code);
-
-    *r_id_old = id_old;
-    return true;
-  }
-  if (id_old != NULL) {
-    /* Local datablock was changed. Restore at the address of the old datablock. */
-    CLOG_INFO(&LOG_UNDO,
-              2,
-              "UNDO: read %s (uuid %u) -> read to old existing address",
-              id->name,
-              id->session_uuid);
-    *r_id_old = id_old;
-    return false;
-  }
-
-  /* Local datablock does not exist in the undo step, so read from scratch. */
-  CLOG_INFO(
-      &LOG_UNDO, 2, "UNDO: read %s (uuid %u) -> read at new address", id->name, id->session_uuid);
-  return false;
-}
-
-/* This routine reads a datablock and its direct data, and advances bhead to
- * the next datablock. For library linked datablocks, only a placeholder will
- * be generated, to be replaced in read_library_linked_ids.
- *
- * When reading for undo, libraries, linked datablocks and unchanged datablocks
- * will be restored from the old database. Only new or changed datablocks will
- * actually be read. */
-static BHead *read_libblock(FileData *fd,
-                            Main *main,
-                            BHead *bhead,
-                            const int tag,
-                            const bool placeholder_set_indirect_extern,
-                            ID **r_id)
-{
-  /* First attempt to restore existing datablocks for undo.
-   * When datablocks are changed but still exist, we restore them at the old
-   * address and inherit recalc flags for the dependency graph. */
-  ID *id_old = NULL;
-  if (fd->flags & FD_FLAGS_IS_MEMFILE) {
-    if (read_libblock_undo_restore(fd, main, bhead, tag, &id_old)) {
-      if (r_id) {
-        *r_id = id_old;
-      }
-      if (main->id_map != NULL) {
-        BKE_main_idmap_insert_id(main->id_map, id_old);
-      }
-
-      return blo_bhead_next(fd, bhead);
-    }
-  }
-
-  /* Read libblock struct. */
-  ID *id = read_struct(fd, bhead, "lib block");
-  if (id == NULL) {
-    if (r_id) {
-      *r_id = NULL;
-    }
-    return blo_bhead_next(fd, bhead);
-  }
-
-  /* Determine ID type and add to main database list. */
-  const short idcode = GS(id->name);
-  ListBase *lb = which_libbase(main, idcode);
-  if (lb == NULL) {
-    /* Unknown ID type. */
-    CLOG_WARN(&LOG, "Unknown id code '%c%c'", (idcode & 0xff), (idcode >> 8));
-    MEM_freeN(id);
-    if (r_id) {
-      *r_id = NULL;
-    }
-    return blo_bhead_next(fd, bhead);
-  }
-
-  /* NOTE: id must be added to the list before direct_link_id(), since
-   * direct_link_library() may remove it from there in case of duplicates. */
-  BLI_addtail(lb, id);
-
-  /* Insert into library map for lookup by newly read datablocks (with pointer value bhead->old).
-   * Note that existing datablocks in memory (which pointer value would be id_old) are not remapped
-   * remapped anymore, so no need to store this info here. */
-  ID *id_target = id_old ? id_old : id;
-  oldnewmap_insert(fd->libmap, bhead->old, id_target, bhead->code);
-
-  if (r_id) {
-    *r_id = id_target;
-  }
-
-  /* Set tag for new datablock to indicate lib linking and versioning needs
-   * to be done still. */
-  int id_tag = tag | LIB_TAG_NEED_LINK | LIB_TAG_NEW;
-
-  if (bhead->code == ID_LINK_PLACEHOLDER) {
-    /* Read placeholder for linked datablock. */
-    id_tag |= LIB_TAG_ID_LINK_PLACEHOLDER;
-
-    if (placeholder_set_indirect_extern) {
-      if (id->flag & LIB_INDIRECT_WEAK_LINK) {
-        id_tag |= LIB_TAG_INDIRECT;
-      }
-      else {
-        id_tag |= LIB_TAG_EXTERN;
-      }
-    }
-
-    direct_link_id(fd, main, id_tag, id, id_old);
-
-    if (main->id_map != NULL) {
-      BKE_main_idmap_insert_id(main->id_map, id);
-    }
-
-    return blo_bhead_next(fd, bhead);
-  }
-
-  /* Read datablock contents.
-   * Use convenient malloc name for debugging and better memory link prints. */
-  const char *allocname = dataname(idcode);
-  bhead = read_data_into_datamap(fd, bhead, allocname);
-  const bool success = direct_link_id(fd, main, id_tag, id, id_old);
-  oldnewmap_clear(fd->datamap);
-
-  if (!success) {
-    /* XXX This is probably working OK currently given the very limited scope of that flag.
-     * However, it is absolutely **not** handled correctly: it is freeing an ID pointer that has
-     * been added to the fd->libmap mapping, which in theory could lead to nice crashes...
-     * This should be properly solved at some point. */
-    BKE_id_free(main, id);
-    if (r_id != NULL) {
-      *r_id = NULL;
-    }
-  }
-  else if (id_old) {
-    /* For undo, store contents read into id at id_old. */
-    read_libblock_undo_restore_at_old_address(fd, main, id, id_old);
-
-    if (main->id_map != NULL) {
-      BKE_main_idmap_insert_id(main->id_map, id_old);
-    }
-  }
-  else if (main->id_map != NULL) {
-    BKE_main_idmap_insert_id(main->id_map, id);
-  }
-
-  return bhead;
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Read Asset Data
- * \{ */
-
-BHead *blo_read_asset_data_block(FileData *fd, BHead *bhead, AssetMetaData **r_asset_data)
-{
-  BLI_assert(blo_bhead_is_id_valid_type(bhead));
-
-  bhead = read_data_into_datamap(fd, bhead, "asset-data read");
-
-  BlendDataReader reader = {fd};
-  BLO_read_data_address(&reader, r_asset_data);
-  BKE_asset_metadata_read(&reader, *r_asset_data);
-
-  oldnewmap_clear(fd->datamap);
-
-  return bhead;
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Read Global Data
- * \{ */
-
-/* NOTE: this has to be kept for reading older files... */
-/* also version info is written here */
-static BHead *read_global(BlendFileData *bfd, FileData *fd, BHead *bhead)
-{
-  FileGlobal *fg = read_struct(fd, bhead, "Global");
-
-  /* copy to bfd handle */
-  bfd->main->subversionfile = fg->subversion;
-  bfd->main->minversionfile = fg->minversion;
-  bfd->main->minsubversionfile = fg->minsubversion;
-  bfd->main->build_commit_timestamp = fg->build_commit_timestamp;
-  BLI_strncpy(bfd->main->build_hash, fg->build_hash, sizeof(bfd->main->build_hash));
-
-  bfd->fileflags = fg->fileflags;
-  bfd->globalf = fg->globalf;
-  STRNCPY(bfd->filepath, fg->filepath);
-
-  /* Error in 2.65 and older: `main->filepath` was not set if you save from startup
-   * (not after loading file). */
-  if (bfd->filepath[0] == 0) {
-    if (fd->fileversion < 265 || (fd->fileversion == 265 && fg->subversion < 1)) {
-      if ((G.fileflags & G_FILE_RECOVER_READ) == 0) {
-        STRNCPY(bfd->filepath, BKE_main_blendfile_path(bfd->main));
-      }
-    }
-
-    /* early 2.50 version patch - filepath not in FileGlobal struct at all */
-    if (fd->fileversion <= 250) {
-      STRNCPY(bfd->filepath, BKE_main_blendfile_path(bfd->main));
-    }
-  }
-
-  if (G.fileflags & G_FILE_RECOVER_READ) {
-    BLI_strncpy(fd->relabase, fg->filepath, sizeof(fd->relabase));
-  }
-
-  bfd->curscreen = fg->curscreen;
-  bfd->curscene = fg->curscene;
-  bfd->cur_view_layer = fg->cur_view_layer;
-
-  MEM_freeN(fg);
-
-  fd->globalf = bfd->globalf;
-  fd->fileflags = bfd->fileflags;
-
-  return blo_bhead_next(fd, bhead);
-}
-
-/* NOTE: this has to be kept for reading older files... */
-static void link_global(FileData *fd, BlendFileData *bfd)
-{
-  bfd->cur_view_layer = blo_read_get_new_globaldata_address(fd, bfd->cur_view_layer);
-  bfd->curscreen = newlibadr(fd, NULL, bfd->curscreen);
-  bfd->curscene = newlibadr(fd, NULL, bfd->curscene);
-  /* this happens in files older than 2.35 */
-  if (bfd->curscene == NULL) {
-    if (bfd->curscreen) {
-      bfd->curscene = bfd->curscreen->scene;
-    }
-  }
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Versioning
- * \{ */
-
-static void do_versions_userdef(FileData *UNUSED(fd), BlendFileData *bfd)
-{
-  UserDef *user = bfd->user;
-
-  if (user == NULL) {
-    return;
-  }
-
-  blo_do_versions_userdef(user);
-}
-
-static void do_versions(FileData *fd, Library *lib, Main *main)
-{
-  /* WATCH IT!!!: pointers from libdata have not been converted */
-
-  /* Don't allow versioning to create new data-blocks. */
-  main->is_locked_for_linking = true;
-
-  if (G.debug & G_DEBUG) {
-    char build_commit_datetime[32];
-    time_t temp_time = main->build_commit_timestamp;
-    struct tm *tm = (temp_time) ? gmtime(&temp_time) : NULL;
-    if (LIKELY(tm)) {
-      strftime(build_commit_datetime, sizeof(build_commit_datetime), "%Y-%m-%d %H:%M", tm);
-    }
-    else {
-      BLI_strncpy(build_commit_datetime, "unknown", sizeof(build_commit_datetime));
-    }
-
-    CLOG_INFO(&LOG, 0, "Read file %s", fd->relabase);
-    CLOG_INFO(&LOG,
-              0,
-              "    Version %d sub %d date %s hash %s",
-              main->versionfile,
-              main->subversionfile,
-              build_commit_datetime,
-              main->build_hash);
-  }
-
-  blo_do_versions_pre250(fd, lib, main);
-  blo_do_versions_250(fd, lib, main);
-  blo_do_versions_260(fd, lib, main);
-  blo_do_versions_270(fd, lib, main);
-  blo_do_versions_280(fd, lib, main);
-  blo_do_versions_290(fd, lib, main);
-  blo_do_versions_300(fd, lib, main);
-  blo_do_versions_cycles(fd, lib, main);
-
-  /* WATCH IT!!!: pointers from libdata have not been converted yet here! */
-  /* WATCH IT 2!: Userdef struct init see do_versions_userdef() above! */
-
-  /* don't forget to set version number in BKE_blender_version.h! */
-
-  main->is_locked_for_linking = false;
-}
-
-static void do_versions_after_linking(Main *main, ReportList *reports)
-{
-  CLOG_INFO(&LOG,
-            2,
-            "Processing %s (%s), %d.%d",
-            main->curlib ? main->curlib->filepath : main->filepath,
-            main->curlib ? "LIB" : "MAIN",
-            main->versionfile,
-            main->subversionfile);
-
-  /* Don't allow versioning to create new data-blocks. */
-  main->is_locked_for_linking = true;
-
-  do_versions_after_linking_250(main);
-  do_versions_after_linking_260(main);
-  do_versions_after_linking_270(main);
-  do_versions_after_linking_280(main, reports);
-  do_versions_after_linking_290(main, reports);
-  do_versions_after_linking_300(main, reports);
-  do_versions_after_linking_cycles(main);
-
-  main->is_locked_for_linking = false;
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Read Library Data Block (all)
- * \{ */
-
-static void lib_link_all(FileData *fd, Main *bmain)
-{
-  const bool do_partial_undo = (fd->skip_flags & BLO_READ_SKIP_UNDO_OLD_MAIN) == 0;
-
-  BlendLibReader reader = {fd, bmain};
-
-  ID *id;
-  FOREACH_MAIN_ID_BEGIN (bmain, id) {
-    if ((id->tag & LIB_TAG_NEED_LINK) == 0) {
-      /* This ID does not need liblink, just skip to next one. */
-      continue;
-    }
-
-    if ((fd->flags & FD_FLAGS_IS_MEMFILE) && GS(id->name) == ID_WM) {
-      /* No load UI for undo memfiles.
-       * Only WM currently, SCR needs it still (see below), and so does WS? */
-      continue;
-    }
-
-    if ((fd->flags & FD_FLAGS_IS_MEMFILE) && do_partial_undo &&
-        (id->tag & LIB_TAG_UNDO_OLD_ID_REUSED) != 0) {
-      /* This ID has been re-used from 'old' bmain. Since it was therefore unchanged across
-       * current undo step, and old IDs re-use their old memory address, we do not need to liblink
-       * it at all. */
-      continue;
-    }
-
-    lib_link_id(&reader, id);
-
-    const IDTypeInfo *id_type = BKE_idtype_get_info_from_id(id);
-    if (id_type->blend_read_lib != NULL) {
-      id_type->blend_read_lib(&reader, id);
-    }
-
-    if (GS(id->name) == ID_LI) {
-      lib_link_library(&reader, (Library *)id); /* Only init users. */
-    }
-
-    id->tag &= ~LIB_TAG_NEED_LINK;
-
-    /* Some data that should be persistent, like the 3DCursor or the tool settings, are
-     * stored in IDs affected by undo, like Scene. So this requires some specific handling. */
-    if (id_type->blend_read_undo_preserve != NULL && id->orig_id != NULL) {
-      id_type->blend_read_undo_preserve(&reader, id, id->orig_id);
-    }
-  }
-  FOREACH_MAIN_ID_END;
-
-  /* Cleanup `ID.orig_id`, this is now reserved for depsgraph/COW usage only. */
-  FOREACH_MAIN_ID_BEGIN (bmain, id) {
-    id->orig_id = NULL;
-  }
-  FOREACH_MAIN_ID_END;
-
-#ifndef NDEBUG
-  /* Double check we do not have any 'need link' tag remaining, this should never be the case once
-   * this function has run. */
-  FOREACH_MAIN_ID_BEGIN (bmain, id) {
-    BLI_assert((id->tag & LIB_TAG_NEED_LINK) == 0);
-  }
-  FOREACH_MAIN_ID_END;
-#endif
-}
-
-/**
- * Checks to perform after `lib_link_all`.
- * Those operations cannot perform properly in a split bmain case, since some data from other
- * bmain's (aka libraries) may not have been processed yet.
- */
-static void after_liblink_merged_bmain_process(Main *bmain)
-{
-  /* We only expect a merged Main here, not a split one. */
-  BLI_assert((bmain->prev == NULL) && (bmain->next == NULL));
-
-  /* Check for possible cycles in scenes' 'set' background property. */
-  lib_link_scenes_check_set(bmain);
-
-  /* We could integrate that to mesh/curve/lattice lib_link, but this is really cheap process,
-   * so simpler to just use it directly in this single call. */
-  BLO_main_validate_shapekeys(bmain, NULL);
-
-  /* We have to rebuild that runtime information *after* all data-blocks have been properly linked.
-   */
-  BKE_main_collections_parent_relations_rebuild(bmain);
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Read User Preferences
- * \{ */
-
-static void direct_link_keymapitem(BlendDataReader *reader, wmKeyMapItem *kmi)
-{
-  BLO_read_data_address(reader, &kmi->properties);
-  IDP_BlendDataRead(reader, &kmi->properties);
-  kmi->ptr = NULL;
-  kmi->flag &= ~KMI_UPDATE;
-}
-
-static BHead *read_userdef(BlendFileData *bfd, FileData *fd, BHead *bhead)
-{
-  UserDef *user;
-  bfd->user = user = read_struct(fd, bhead, "user def");
-
-  /* User struct has separate do-version handling */
-  user->versionfile = bfd->main->versionfile;
-  user->subversionfile = bfd->main->subversionfile;
-
-  /* read all data into fd->datamap */
-  bhead = read_data_into_datamap(fd, bhead, "user def");
-
-  BlendDataReader reader_ = {fd};
-  BlendDataReader *reader = &reader_;
-
-  BLO_read_list(reader, &user->themes);
-  BLO_read_list(reader, &user->user_keymaps);
-  BLO_read_list(reader, &user->user_keyconfig_prefs);
-  BLO_read_list(reader, &user->user_menus);
-  BLO_read_list(reader, &user->addons);
-  BLO_read_list(reader, &user->autoexec_paths);
-  BLO_read_list(reader, &user->asset_libraries);
-
-  LISTBASE_FOREACH (wmKeyMap *, keymap, &user->user_keymaps) {
-    keymap->modal_items = NULL;
-    keymap->poll = NULL;
-    keymap->flag &= ~KEYMAP_UPDATE;
-
-    BLO_read_list(reader, &keymap->diff_items);
-    BLO_read_list(reader, &keymap->items);
-
-    LISTBASE_FOREACH (wmKeyMapDiffItem *, kmdi, &keymap->diff_items) {
-      BLO_read_data_address(reader, &kmdi->remove_item);
-      BLO_read_data_address(reader, &kmdi->add_item);
-
-      if (kmdi->remove_item) {
-        direct_link_keymapitem(reader, kmdi->remove_item);
-      }
-      if (kmdi->add_item) {
-        direct_link_keymapitem(reader, kmdi->add_item);
-      }
-    }
-
-    LISTBASE_FOREACH (wmKeyMapItem *, kmi, &keymap->items) {
-      direct_link_keymapitem(reader, kmi);
-    }
-  }
-
-  LISTBASE_FOREACH (wmKeyConfigPref *, kpt, &user->user_keyconfig_prefs) {
-    BLO_read_data_address(reader, &kpt->prop);
-    IDP_BlendDataRead(reader, &kpt->prop);
-  }
-
-  LISTBASE_FOREACH (bUserMenu *, um, &user->user_menus) {
-    BLO_read_list(reader, &um->items);
-    LISTBASE_FOREACH (bUserMenuItem *, umi, &um->items) {
-      if (umi->type == USER_MENU_TYPE_OPERATOR) {
-        bUserMenuItem_Op *umi_op = (bUserMenuItem_Op *)umi;
-        BLO_read_data_address(reader, &umi_op->prop);
-        IDP_BlendDataRead(reader, &umi_op->prop);
-      }
-    }
-  }
-
-  LISTBASE_FOREACH (bAddon *, addon, &user->addons) {
-    BLO_read_data_address(reader, &addon->prop);
-    IDP_BlendDataRead(reader, &addon->prop);
-  }
-
-  /* XXX */
-  user->uifonts.first = user->uifonts.last = NULL;
-
-  BLO_read_list(reader, &user->uistyles);
-
-  /* Don't read the active app template, use the default one. */
-  user->app_template[0] = '\0';
-
-  /* Clear runtime data. */
-  user->runtime.is_dirty = false;
-  user->edit_studio_light = 0;
-
-  /* free fd->datamap again */
-  oldnewmap_clear(fd->datamap);
-
-  return bhead;
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Read File (Internal)
- * \{ */
-
-BlendFileData *blo_read_file_internal(FileData *fd, const char *filepath)
-{
-  BHead *bhead = blo_bhead_first(fd);
-  BlendFileData *bfd;
-  ListBase mainlist = {NULL, NULL};
-
-  if (fd->flags & FD_FLAGS_IS_MEMFILE) {
-    CLOG_INFO(&LOG_UNDO, 2, "UNDO: read step");
-  }
-
-  bfd = MEM_callocN(sizeof(BlendFileData), "blendfiledata");
-
-  bfd->main = BKE_main_new();
-  bfd->main->versionfile = fd->fileversion;
-
-  bfd->type = BLENFILETYPE_BLEND;
-
-  if ((fd->skip_flags & BLO_READ_SKIP_DATA) == 0) {
-    BLI_addtail(&mainlist, bfd->main);
-    fd->mainlist = &mainlist;
-    STRNCPY(bfd->main->filepath, filepath);
-  }
-
-  if (G.background) {
-    /* We only read & store .blend thumbnail in background mode
-     * (because we cannot re-generate it, no OpenGL available).
-     */
-    const int *data = read_file_thumbnail(fd);
-
-    if (data) {
-      const int width = data[0];
-      const int height = data[1];
-      if (BLEN_THUMB_MEMSIZE_IS_VALID(width, height)) {
-        const size_t data_size = BLEN_THUMB_MEMSIZE(width, height);
-        bfd->main->blen_thumb = MEM_mallocN(data_size, __func__);
-
-        BLI_assert((data_size - sizeof(*bfd->main->blen_thumb)) ==
-                   (BLEN_THUMB_MEMSIZE_FILE(width, height) - (sizeof(*data) * 2)));
-        bfd->main->blen_thumb->width = width;
-        bfd->main->blen_thumb->height = height;
-        memcpy(bfd->main->blen_thumb->rect, &data[2], data_size - sizeof(*bfd->main->blen_thumb));
-      }
-    }
-  }
-
-  while (bhead) {
-    switch (bhead->code) {
-      case DATA:
-      case DNA1:
-      case TEST: /* used as preview since 2.5x */
-      case REND:
-        bhead = blo_bhead_next(fd, bhead);
-        break;
-      case GLOB:
-        bhead = read_global(bfd, fd, bhead);
-        break;
-      case USER:
-        if (fd->skip_flags & BLO_READ_SKIP_USERDEF) {
-          bhead = blo_bhead_next(fd, bhead);
-        }
-        else {
-          bhead = read_userdef(bfd, fd, bhead);
-        }
-        break;
-      case ENDB:
-        bhead = NULL;
-        break;
-
-      case ID_LINK_PLACEHOLDER:
-        if (fd->skip_flags & BLO_READ_SKIP_DATA) {
-          bhead = blo_bhead_next(fd, bhead);
-        }
-        else {
-          /* Add link placeholder to the main of the library it belongs to.
-           * The library is the most recently loaded ID_LI block, according
-           * to the file format definition. So we can use the entry at the
-           * end of mainlist, added in direct_link_library. */
-          Main *libmain = mainlist.last;
-          bhead = read_libblock(fd, libmain, bhead, 0, true, NULL);
-        }
-        break;
-        /* in 2.50+ files, the file identifier for screens is patched, forward compatibility */
-      case ID_SCRN:
-        bhead->code = ID_SCR;
-        /* pass on to default */
-        ATTR_FALLTHROUGH;
-      default:
-        if (fd->skip_flags & BLO_READ_SKIP_DATA) {
-          bhead = blo_bhead_next(fd, bhead);
-        }
-        else {
-          bhead = read_libblock(fd, bfd->main, bhead, LIB_TAG_LOCAL, false, NULL);
-        }
-    }
-  }
-
-  /* do before read_libraries, but skip undo case */
-  if ((fd->flags & FD_FLAGS_IS_MEMFILE) == 0) {
-    if ((fd->skip_flags & BLO_READ_SKIP_DATA) == 0) {
-      do_versions(fd, NULL, bfd->main);
-    }
-
-    if ((fd->skip_flags & BLO_READ_SKIP_USERDEF) == 0) {
-      do_versions_userdef(fd, bfd);
-    }
-  }
-
-  if ((fd->skip_flags & BLO_READ_SKIP_DATA) == 0) {
-    fd->reports->duration.libraries = PIL_check_seconds_timer();
-    read_libraries(fd, &mainlist);
-
-    blo_join_main(&mainlist);
-
-    lib_link_all(fd, bfd->main);
-    after_liblink_merged_bmain_process(bfd->main);
-
-    fd->reports->duration.libraries = PIL_check_seconds_timer() - fd->reports->duration.libraries;
-
-    /* Skip in undo case. */
-    if ((fd->flags & FD_FLAGS_IS_MEMFILE) == 0) {
-      /* Note that we can't recompute user-counts at this point in undo case, we play too much with
-       * IDs from different memory realms, and Main database is not in a fully valid state yet.
-       */
-      /* Some versioning code does expect some proper user-reference-counting, e.g. in conversion
-       * from groups to collections... We could optimize out that first call when we are reading a
-       * current version file, but again this is really not a bottle neck currently.
-       * So not worth it. */
-      BKE_main_id_refcount_recompute(bfd->main, false);
-
-      /* Yep, second splitting... but this is a very cheap operation, so no big deal. */
-      blo_split_main(&mainlist, bfd->main);
-      LISTBASE_FOREACH (Main *, mainvar, &mainlist) {
-        BLI_assert(mainvar->versionfile != 0);
-        do_versions_after_linking(mainvar, fd->reports->reports);
-      }
-      blo_join_main(&mainlist);
-
-      /* And we have to compute those user-reference-counts again, as `do_versions_after_linking()`
-       * does not always properly handle user counts, and/or that function does not take into
-       * account old, deprecated data. */
-      BKE_main_id_refcount_recompute(bfd->main, false);
-    }
-
-    /* After all data has been read and versioned, uses LIB_TAG_NEW. Theoretically this should
-     * not be calculated in the undo case, but it is currently needed even on undo to recalculate
-     * a cache. */
-    ntreeUpdateAllNew(bfd->main);
-
-    placeholders_ensure_valid(bfd->main);
-
-    BKE_main_id_tag_all(bfd->main, LIB_TAG_NEW, false);
-
-    /* Now that all our data-blocks are loaded,
-     * we can re-generate overrides from their references. */
-    if ((fd->flags & FD_FLAGS_IS_MEMFILE) == 0) {
-      /* Do not apply in undo case! */
-      fd->reports->duration.lib_overrides = PIL_check_seconds_timer();
-
-      BKE_lib_override_library_main_validate(bfd->main, fd->reports->reports);
-      BKE_lib_override_library_main_update(bfd->main);
-
-      fd->reports->duration.lib_overrides = PIL_check_seconds_timer() -
-                                            fd->reports->duration.lib_overrides;
-    }
-
-    BKE_collections_after_lib_link(bfd->main);
-
-    /* Make all relative paths, relative to the open blend file. */
-    fix_relpaths_library(fd->relabase, bfd->main);
-
-    link_global(fd, bfd); /* as last */
-  }
-
-  fd->mainlist = NULL; /* Safety, this is local variable, shall not be used afterward. */
-
-  BLI_assert(bfd->main->id_map == NULL);
-
-  return bfd;
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Library Linking
- *
- * Also used for append.
- * \{ */
-
-struct BHeadSort {
-  BHead *bhead;
-  const void *old;
-};
-
-static int verg_bheadsort(const void *v1, const void *v2)
-{
-  const struct BHeadSort *x1 = v1, *x2 = v2;
-
-  if (x1->old > x2->old) {
-    return 1;
-  }
-  if (x1->old < x2->old) {
-    return -1;
-  }
-  return 0;
-}
-
-static void sort_bhead_old_map(FileData *fd)
-{
-  BHead *bhead;
-  struct BHeadSort *bhs;
-  int tot = 0;
-
-  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
-    tot++;
-  }
-
-  fd->tot_bheadmap = tot;
-  if (tot == 0) {
-    return;
-  }
-
-  bhs = fd->bheadmap = MEM_malloc_arrayN(tot, sizeof(struct BHeadSort), "BHeadSort");
-
-  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead), bhs++) {
-    bhs->bhead = bhead;
-    bhs->old = bhead->old;
-  }
-
-  qsort(fd->bheadmap, tot, sizeof(struct BHeadSort), verg_bheadsort);
-}
-
-static BHead *find_previous_lib(FileData *fd, BHead *bhead)
-{
-  /* Skip library data-blocks in undo, see comment in read_libblock. */
-  if (fd->flags & FD_FLAGS_IS_MEMFILE) {
-    return NULL;
-  }
-
-  for (; bhead; bhead = blo_bhead_prev(fd, bhead)) {
-    if (bhead->code == ID_LI) {
-      break;
-    }
-  }
-
-  return bhead;
-}
-
-static BHead *find_bhead(FileData *fd, void *old)
-{
-#if 0
-  BHead* bhead;
-#endif
-  struct BHeadSort *bhs, bhs_s;
-
-  if (!old) {
-    return NULL;
-  }
-
-  if (fd->bheadmap == NULL) {
-    sort_bhead_old_map(fd);
-  }
-
-  bhs_s.old = old;
-  bhs = bsearch(&bhs_s, fd->bheadmap, fd->tot_bheadmap, sizeof(struct BHeadSort), verg_bheadsort);
-
-  if (bhs) {
-    return bhs->bhead;
-  }
-
-#if 0
-  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
-    if (bhead->old == old) {
-      return bhead;
-    }
-  }
-#endif
-
-  return NULL;
-}
-
-static BHead *find_bhead_from_code_name(FileData *fd, const short idcode, const char *name)
-{
-#ifdef USE_GHASH_BHEAD
-
-  char idname_full[MAX_ID_NAME];
-
-  *((short *)idname_full) = idcode;
-  BLI_strncpy(idname_full + 2, name, sizeof(idname_full) - 2);
-
-  return BLI_ghash_lookup(fd->bhead_idname_hash, idname_full);
-
-#else
-  BHead *bhead;
-
-  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
-    if (bhead->code == idcode) {
-      const char *idname_test = blo_bhead_id_name(fd, bhead);
-      if (STREQ(idname_test + 2, name)) {
-        return bhead;
-      }
-    }
-    else if (bhead->code == ENDB) {
-      break;
-    }
-  }
-
-  return NULL;
-#endif
-}
-
-static BHead *find_bhead_from_idname(FileData *fd, const char *idname)
-{
-#ifdef USE_GHASH_BHEAD
-  return BLI_ghash_lookup(fd->bhead_idname_hash, idname);
-#else
-  return find_bhead_from_code_name(fd, GS(idname), idname + 2);
-#endif
-}
-
-static ID *is_yet_read(FileData *fd, Main *mainvar, BHead *bhead)
-{
-  if (mainvar->id_map == NULL) {
-    mainvar->id_map = BKE_main_idmap_create(mainvar, false, NULL, MAIN_IDMAP_TYPE_NAME);
-  }
-  BLI_assert(BKE_main_idmap_main_get(mainvar->id_map) == mainvar);
-
-  const char *idname = blo_bhead_id_name(fd, bhead);
-
-  ID *id = BKE_main_idmap_lookup_name(mainvar->id_map, GS(idname), idname + 2, mainvar->curlib);
-  BLI_assert(id == BLI_findstring(which_libbase(mainvar, GS(idname)), idname, offsetof(ID, name)));
-  return id;
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Library Linking (expand pointers)
- * \{ */
-
-static void expand_doit_library(void *fdhandle, Main *mainvar, void *old)
-{
-  FileData *fd = fdhandle;
-
-  BHead *bhead = find_bhead(fd, old);
-  if (bhead == NULL) {
-    return;
-  }
-
-  if (bhead->code == ID_LINK_PLACEHOLDER) {
-    /* Placeholder link to data-lock in another library. */
-    BHead *bheadlib = find_previous_lib(fd, bhead);
-    if (bheadlib == NULL) {
-      return;
-    }
-
-    Library *lib = read_struct(fd, bheadlib, "Library");
-    Main *libmain = blo_find_main(fd, lib->filepath, fd->relabase);
-
-    if (libmain->curlib == NULL) {
-      const char *idname = blo_bhead_id_name(fd, bhead);
-
-      BLO_reportf_wrap(fd->reports,
-                       RPT_WARNING,
-                       TIP_("LIB: Data refers to main .blend file: '%s' from %s"),
-                       idname,
-                       mainvar->curlib->filepath_abs);
-      return;
-    }
-
-    ID *id = is_yet_read(fd, libmain, bhead);
-
-    if (id == NULL) {
-      /* ID has not been read yet, add placeholder to the main of the
-       * library it belongs to, so that it will be read later. */
-      read_libblock(fd, libmain, bhead, fd->id_tag_extra | LIB_TAG_INDIRECT, false, &id);
-      id_sort_by_name(which_libbase(libmain, GS(id->name)), id, id->prev);
-
-      /* commented because this can print way too much */
-      // if (G.debug & G_DEBUG) printf("expand_doit: other lib %s\n", lib->filepath);
-
-      /* for outliner dependency only */
-      libmain->curlib->parent = mainvar->curlib;
-    }
-    else {
-      /* Convert any previously read weak link to regular link
-       * to signal that we want to read this data-block. */
-      if (id->tag & LIB_TAG_ID_LINK_PLACEHOLDER) {
-        id->flag &= ~LIB_INDIRECT_WEAK_LINK;
-      }
-
-      /* "id" is either a placeholder or real ID that is already in the
-       * main of the library (A) it belongs to. However it might have been
-       * put there by another library (C) which only updated its own
-       * fd->libmap. In that case we also need to update the fd->libmap
-       * of the current library (B) so we can find it for lookups.
-       *
-       * An example of such a setup is:
-       * (A) tree.blend: contains Tree object.
-       * (B) forest.blend: contains Forest collection linking in Tree from tree.blend.
-       * (C) shot.blend: links in both Tree from tree.blend and Forest from forest.blend.
-       */
-      oldnewmap_insert(fd->libmap, bhead->old, id, bhead->code);
-
-      /* If "id" is a real data-lock and not a placeholder, we need to
-       * update fd->libmap to replace ID_LINK_PLACEHOLDER with the real
-       * ID_* code.
-       *
-       * When the real ID is read this replacement happens for all
-       * libraries read so far, but not for libraries that have not been
-       * read yet at that point. */
-      change_link_placeholder_to_real_ID_pointer_fd(fd, bhead->old, id);
-
-      /* Commented because this can print way too much. */
-#if 0
-      if (G.debug & G_DEBUG) {
-        printf("expand_doit: already linked: %s lib: %s\n", id->name, lib->filepath);
-      }
-#endif
-    }
-
-    MEM_freeN(lib);
-  }
-  else {
-    /* Data-block in same library. */
-    /* In 2.50+ file identifier for screens is patched, forward compatibility. */
-    if (bhead->code == ID_SCRN) {
-      bhead->code = ID_SCR;
-    }
-
-    ID *id = is_yet_read(fd, mainvar, bhead);
-    if (id == NULL) {
-      read_libblock(fd,
-                    mainvar,
-                    bhead,
-                    fd->id_tag_extra | LIB_TAG_NEED_EXPAND | LIB_TAG_INDIRECT,
-                    false,
-                    &id);
-      id_sort_by_name(which_libbase(mainvar, GS(id->name)), id, id->prev);
-    }
-    else {
-      /* Convert any previously read weak link to regular link
-       * to signal that we want to read this data-block. */
-      if (id->tag & LIB_TAG_ID_LINK_PLACEHOLDER) {
-        id->flag &= ~LIB_INDIRECT_WEAK_LINK;
-      }
-
-      /* this is actually only needed on UI call? when ID was already read before,
-       * and another append happens which invokes same ID...
-       * in that case the lookup table needs this entry */
-      oldnewmap_insert(fd->libmap, bhead->old, id, bhead->code);
-      /* commented because this can print way too much */
-      // if (G.debug & G_DEBUG) printf("expand: already read %s\n", id->name);
-    }
-  }
-}
-
-static BLOExpandDoitCallback expand_doit;
-
-static void expand_id(BlendExpander *expander, ID *id);
-
-static void expand_id_embedded_id(BlendExpander *expander, ID *id)
-{
-  /* Handle 'private IDs'. */
-  bNodeTree *nodetree = ntreeFromID(id);
-  if (nodetree != NULL) {
-    expand_id(expander, &nodetree->id);
-    ntreeBlendReadExpand(expander, nodetree);
-  }
-
-  if (GS(id->name) == ID_SCE) {
-    Scene *scene = (Scene *)id;
-    if (scene->master_collection != NULL) {
-      expand_id(expander, &scene->master_collection->id);
-      BKE_collection_blend_read_expand(expander, scene->master_collection);
-    }
-  }
-}
-
-static void expand_id(BlendExpander *expander, ID *id)
-{
-  IDP_BlendReadExpand(expander, id->properties);
-
-  if (id->override_library) {
-    BLO_expand(expander, id->override_library->reference);
-    BLO_expand(expander, id->override_library->storage);
-  }
-
-  AnimData *adt = BKE_animdata_from_id(id);
-  if (adt != NULL) {
-    BKE_animdata_blend_read_expand(expander, adt);
-  }
-
-  expand_id_embedded_id(expander, id);
-}
-
-void BLO_main_expander(BLOExpandDoitCallback expand_doit_func)
-{
-  expand_doit = expand_doit_func;
-}
-
-void BLO_expand_main(void *fdhandle, Main *mainvar)
-{
-  ListBase *lbarray[INDEX_ID_MAX];
-  FileData *fd = fdhandle;
-  ID *id;
-  int a;
-  bool do_it = true;
-
-  BlendExpander expander = {fd, mainvar};
-
-  while (do_it) {
-    do_it = false;
-
-    a = set_listbasepointers(mainvar, lbarray);
-    while (a--) {
-      id = lbarray[a]->first;
-      while (id) {
-        if (id->tag & LIB_TAG_NEED_EXPAND) {
-          expand_id(&expander, id);
-
-          const IDTypeInfo *id_type = BKE_idtype_get_info_from_id(id);
-          if (id_type->blend_read_expand != NULL) {
-            id_type->blend_read_expand(&expander, id);
-          }
-
-          do_it = true;
-          id->tag &= ~LIB_TAG_NEED_EXPAND;
-        }
-        id = id->next;
-      }
-    }
-  }
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Library Linking (helper functions)
- * \{ */
-
-/* returns true if the item was found
- * but it may already have already been appended/linked */
-static ID *link_named_part(
-    Main *mainl, FileData *fd, const short idcode, const char *name, const int flag)
-{
-  BHead *bhead = find_bhead_from_code_name(fd, idcode, name);
-  ID *id;
-
-  const bool use_placeholders = (flag & BLO_LIBLINK_USE_PLACEHOLDERS) != 0;
-  const bool force_indirect = (flag & BLO_LIBLINK_FORCE_INDIRECT) != 0;
-
-  BLI_assert(BKE_idtype_idcode_is_linkable(idcode) && BKE_idtype_idcode_is_valid(idcode));
-
-  if (bhead) {
-    id = is_yet_read(fd, mainl, bhead);
-    if (id == NULL) {
-      /* not read yet */
-      const int tag = ((force_indirect ? LIB_TAG_INDIRECT : LIB_TAG_EXTERN) | fd->id_tag_extra);
-      read_libblock(fd, mainl, bhead, tag | LIB_TAG_NEED_EXPAND, false, &id);
-
-      if (id) {
-        /* sort by name in list */
-        ListBase *lb = which_libbase(mainl, idcode);
-        id_sort_by_name(lb, id, NULL);
-      }
-    }
-    else {
-      /* already linked */
-      CLOG_WARN(&LOG, "Append: ID '%s' is already linked", id->name);
-      oldnewmap_insert(fd->libmap, bhead->old, id, bhead->code);
-      if (!force_indirect && (id->tag & LIB_TAG_INDIRECT)) {
-        id->tag &= ~LIB_TAG_INDIRECT;
-        id->flag &= ~LIB_INDIRECT_WEAK_LINK;
-        id->tag |= LIB_TAG_EXTERN;
-      }
-    }
-  }
-  else if (use_placeholders) {
-    /* XXX flag part is weak! */
-    id = create_placeholder(
-        mainl, idcode, name, force_indirect ? LIB_TAG_INDIRECT : LIB_TAG_EXTERN);
-  }
-  else {
-    id = NULL;
-  }
-
-  /* if we found the id but the id is NULL, this is really bad */
-  BLI_assert(!((bhead != NULL) && (id == NULL)));
-
-  return id;
-}
-
-ID *BLO_library_link_named_part(Main *mainl,
-                                BlendHandle **bh,
-                                const short idcode,
-                                const char *name,
-                                const struct LibraryLink_Params *params)
-{
-  FileData *fd = (FileData *)(*bh);
-  return link_named_part(mainl, fd, idcode, name, params->flag);
-}
-
-/* common routine to append/link something from a library */
-
-static Main *library_link_begin(Main *mainvar,
-                                FileData **fd,
-                                const char *filepath,
-                                const int id_tag_extra)
-{
-  Main *mainl;
-
-  /* Only allow specific tags to be set as extra,
-   * otherwise this could conflict with library loading logic.
-   * Other flags can be added here, as long as they are safe. */
-  BLI_assert((id_tag_extra & ~LIB_TAG_TEMP_MAIN) == 0);
-
-  (*fd)->id_tag_extra = id_tag_extra;
-
-  (*fd)->mainlist = MEM_callocN(sizeof(ListBase), "FileData.mainlist");
-
-  /* make mains */
-  blo_split_main((*fd)->mainlist, mainvar);
-
-  /* which one do we need? */
-  mainl = blo_find_main(*fd, filepath, BKE_main_blendfile_path(mainvar));
-
-  /* needed for do_version */
-  mainl->versionfile = (*fd)->fileversion;
-  read_file_version(*fd, mainl);
-#ifdef USE_GHASH_BHEAD
-  read_file_bhead_idname_map_create(*fd);
-#endif
-
-  return mainl;
-}
-
-void BLO_library_link_params_init(struct LibraryLink_Params *params,
-                                  struct Main *bmain,
-                                  const int flag,
-                                  const int id_tag_extra)
-{
-  memset(params, 0, sizeof(*params));
-  params->bmain = bmain;
-  params->flag = flag;
-  params->id_tag_extra = id_tag_extra;
-}
-
-void BLO_library_link_params_init_with_context(struct LibraryLink_Params *params,
-                                               struct Main *bmain,
-                                               const int flag,
-                                               const int id_tag_extra,
-                                               /* Context arguments. */
-                                               struct Scene *scene,
-                                               struct ViewLayer *view_layer,
-                                               const struct View3D *v3d)
-{
-  BLO_library_link_params_init(params, bmain, flag, id_tag_extra);
-  if (scene != NULL) {
-    params->context.scene = scene;
-    params->context.view_layer = view_layer;
-    params->context.v3d = v3d;
-  }
-}
-
-Main *BLO_library_link_begin(BlendHandle **bh,
-                             const char *filepath,
-                             const struct LibraryLink_Params *params)
-{
-  FileData *fd = (FileData *)(*bh);
-  return library_link_begin(params->bmain, &fd, filepath, params->id_tag_extra);
-}
-
-static void split_main_newid(Main *mainptr, Main *main_newid)
-{
-  /* We only copy the necessary subset of data in this temp main. */
-  main_newid->versionfile = mainptr->versionfile;
-  main_newid->subversionfile = mainptr->subversionfile;
-  STRNCPY(main_newid->filepath, mainptr->filepath);
-  main_newid->curlib = mainptr->curlib;
-
-  ListBase *lbarray[INDEX_ID_MAX];
-  ListBase *lbarray_newid[INDEX_ID_MAX];
-  int i = set_listbasepointers(mainptr, lbarray);
-  set_listbasepointers(main_newid, lbarray_newid);
-  while (i--) {
-    BLI_listbase_clear(lbarray_newid[i]);
-
-    LISTBASE_FOREACH_MUTABLE (ID *, id, lbarray[i]) {
-      if (id->tag & LIB_TAG_NEW) {
-        BLI_remlink(lbarray[i], id);
-        BLI_addtail(lbarray_newid[i], id);
-      }
-    }
-  }
-}
-
-static void library_link_end(Main *mainl, FileData **fd, const int flag)
-{
-  Main *mainvar;
-  Library *curlib;
-
-  if (mainl->id_map == NULL) {
-    mainl->id_map = BKE_main_idmap_create(mainl, false, NULL, MAIN_IDMAP_TYPE_NAME);
-  }
-
-  /* expander now is callback function */
-  BLO_main_expander(expand_doit_library);
-
-  /* make main consistent */
-  BLO_expand_main(*fd, mainl);
-
-  /* do this when expand found other libs */
-  read_libraries(*fd, (*fd)->mainlist);
-
-  curlib = mainl->curlib;
-
-  /* make the lib path relative if required */
-  if (flag & FILE_RELPATH) {
-    /* use the full path, this could have been read by other library even */
-    BLI_strncpy(curlib->filepath, curlib->filepath_abs, sizeof(curlib->filepath));
-
-    /* uses current .blend file as reference */
-    BLI_path_rel(curlib->filepath, BKE_main_blendfile_path_from_global());
-  }
-
-  blo_join_main((*fd)->mainlist);
-  mainvar = (*fd)->mainlist->first;
-  mainl = NULL; /* blo_join_main free's mainl, can't use anymore */
-
-  lib_link_all(*fd, mainvar);
-  after_liblink_merged_bmain_process(mainvar);
-
-  /* Some versioning code does expect some proper userrefcounting, e.g. in conversion from
-   * groups to collections... We could optimize out that first call when we are reading a
-   * current version file, but again this is really not a bottle neck currently. so not worth
-   * it. */
-  BKE_main_id_refcount_recompute(mainvar, false);
-
-  BKE_collections_after_lib_link(mainvar);
-
-  /* Yep, second splitting... but this is a very cheap operation, so no big deal. */
-  blo_split_main((*fd)->mainlist, mainvar);
-  Main *main_newid = BKE_main_new();
-  for (mainvar = ((Main *)(*fd)->mainlist->first)->next; mainvar; mainvar = mainvar->next) {
-    BLI_assert(mainvar->versionfile != 0);
-    /* We need to split out IDs already existing,
-     * or they will go again through do_versions - bad, very bad! */
-    split_main_newid(mainvar, main_newid);
-
-    do_versions_after_linking(main_newid, (*fd)->reports->reports);
-
-    add_main_to_main(mainvar, main_newid);
-  }
-
-  blo_join_main((*fd)->mainlist);
-  mainvar = (*fd)->mainlist->first;
-  MEM_freeN((*fd)->mainlist);
-
-  /* This does not take into account old, deprecated data, so we also have to do it after
-   * `do_versions_after_linking()`. */
-  BKE_main_id_refcount_recompute(mainvar, false);
-
-  /* After all data has been read and versioned, uses LIB_TAG_NEW. */
-  ntreeUpdateAllNew(mainvar);
-
-  placeholders_ensure_valid(mainvar);
-
-  /* Apply overrides of newly linked data if needed. Already existing IDs need to split out, to
-   * avoid re-applying their own overrides. */
-  BLI_assert(BKE_main_is_empty(main_newid));
-  split_main_newid(mainvar, main_newid);
-  BKE_lib_override_library_main_validate(main_newid, (*fd)->reports->reports);
-  BKE_lib_override_library_main_update(main_newid);
-  add_main_to_main(mainvar, main_newid);
-  BKE_main_free(main_newid);
-
-  BKE_main_id_tag_all(mainvar, LIB_TAG_NEW, false);
-
-  /* Make all relative paths, relative to the open blend file. */
-  fix_relpaths_library(BKE_main_blendfile_path(mainvar), mainvar);
-
-  /* patch to prevent switch_endian happens twice */
-  if ((*fd)->flags & FD_FLAGS_SWITCH_ENDIAN) {
-    blo_filedata_free(*fd);
-    *fd = NULL;
-  }
-}
-
-void BLO_library_link_end(Main *mainl, BlendHandle **bh, const struct LibraryLink_Params *params)
-{
-  FileData *fd = (FileData *)(*bh);
-  library_link_end(mainl, &fd, params->flag);
-  *bh = (BlendHandle *)fd;
-}
-
-void *BLO_library_read_struct(FileData *fd, BHead *bh, const char *blockname)
-{
-  return read_struct(fd, bh, blockname);
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Library Reading
- * \{ */
-
-static int has_linked_ids_to_read(Main *mainvar)
-{
-  ListBase *lbarray[INDEX_ID_MAX];
-  int a = set_listbasepointers(mainvar, lbarray);
-
-  while (a--) {
-    LISTBASE_FOREACH (ID *, id, lbarray[a]) {
-      if ((id->tag & LIB_TAG_ID_LINK_PLACEHOLDER) && !(id->flag & LIB_INDIRECT_WEAK_LINK)) {
-        return true;
-      }
-    }
-  }
-
-  return false;
-}
-
-static void read_library_linked_id(
-    FileData *basefd, FileData *fd, Main *mainvar, ID *id, ID **r_id)
-{
-  BHead *bhead = NULL;
-  const bool is_valid = BKE_idtype_idcode_is_linkable(GS(id->name)) ||
-                        ((id->tag & LIB_TAG_EXTERN) == 0);
-
-  if (fd) {
-    bhead = find_bhead_from_idname(fd, id->name);
-  }
-
-  if (!is_valid) {
-    BLO_reportf_wrap(basefd->reports,
-                     RPT_ERROR,
-                     TIP_("LIB: %s: '%s' is directly linked from '%s' (parent '%s'), but is a "
-                          "non-linkable data type"),
-                     BKE_idtype_idcode_to_name(GS(id->name)),
-                     id->name + 2,
-                     mainvar->curlib->filepath_abs,
-                     library_parent_filepath(mainvar->curlib));
-  }
-
-  id->tag &= ~LIB_TAG_ID_LINK_PLACEHOLDER;
-  id->flag &= ~LIB_INDIRECT_WEAK_LINK;
-
-  if (bhead) {
-    id->tag |= LIB_TAG_NEED_EXPAND;
-    // printf("read lib block %s\n", id->name);
-    read_libblock(fd, mainvar, bhead, id->tag, false, r_id);
-  }
-  else {
-    BLO_reportf_wrap(basefd->reports,
-                     RPT_INFO,
-                     TIP_("LIB: %s: '%s' missing from '%s', parent '%s'"),
-                     BKE_idtype_idcode_to_name(GS(id->name)),
-                     id->name + 2,
-                     mainvar->curlib->filepath_abs,
-                     library_parent_filepath(mainvar->curlib));
-    basefd->reports->count.missing_linked_id++;
-
-    /* Generate a placeholder for this ID (simplified version of read_libblock actually...). */
-    if (r_id) {
-      *r_id = is_valid ? create_placeholder(mainvar, GS(id->name), id->name + 2, id->tag) : NULL;
-    }
-  }
-}
-
-static void read_library_linked_ids(FileData *basefd,
-                                    FileData *fd,
-                                    ListBase *mainlist,
-                                    Main *mainvar)
-{
-  GHash *loaded_ids = BLI_ghash_str_new(__func__);
-
-  ListBase *lbarray[INDEX_ID_MAX];
-  int a = set_listbasepointers(mainvar, lbarray);
-
-  while (a--) {
-    ID *id = lbarray[a]->first;
-    ListBase pending_free_ids = {NULL};
-
-    while (id) {
-      ID *id_next = id->next;
-      if ((id->tag & LIB_TAG_ID_LINK_PLACEHOLDER) && !(id->flag & LIB_INDIRECT_WEAK_LINK)) {
-        BLI_remlink(lbarray[a], id);
-        if (mainvar->id_map != NULL) {
-          BKE_main_idmap_remove_id(mainvar->id_map, id);
-        }
-
-        /* When playing with lib renaming and such, you may end with cases where
-         * you have more than one linked ID of the same data-block from same
-         * library. This is absolutely horrible, hence we use a ghash to ensure
-         * we go back to a single linked data when loading the file. */
-        ID **realid = NULL;
-        if (!BLI_ghash_ensure_p(loaded_ids, id->name, (void ***)&realid)) {
-          read_library_linked_id(basefd, fd, mainvar, id, realid);
-        }
-
-        /* `realid` shall never be NULL - unless some source file/lib is broken
-         * (known case: some directly linked shapekey from a missing lib...). */
-        // BLI_assert(*realid != NULL);
-
-        /* Now that we have a real ID, replace all pointers to placeholders in
-         * fd->libmap with pointers to the real data-blocks. We do this for all
-         * libraries since multiple might be referencing this ID. */
-        change_link_placeholder_to_real_ID_pointer(mainlist, basefd, id, *realid);
-
-        /* We cannot free old lib-ref placeholder ID here anymore, since we use
-         * its name as key in loaded_ids hash. */
-        BLI_addtail(&pending_free_ids, id);
-      }
-      id = id_next;
-    }
-
-    /* Clear GHash and free link placeholder IDs of the current type. */
-    BLI_ghash_clear(loaded_ids, NULL, NULL);
-    BLI_freelistN(&pending_free_ids);
-  }
-
-  BLI_ghash_free(loaded_ids, NULL, NULL);
-}
-
-static void read_library_clear_weak_links(FileData *basefd, ListBase *mainlist, Main *mainvar)
-{
-  /* Any remaining weak links at this point have been lost, silently drop
-   * those by setting them to NULL pointers. */
-  ListBase *lbarray[INDEX_ID_MAX];
-  int a = set_listbasepointers(mainvar, lbarray);
-
-  while (a--) {
-    ID *id = lbarray[a]->first;
-
-    while (id) {
-      ID *id_next = id->next;
-      if ((id->tag & LIB_TAG_ID_LINK_PLACEHOLDER) && (id->flag & LIB_INDIRECT_WEAK_LINK)) {
-        CLOG_INFO(&LOG, 3, "Dropping weak link to '%s'", id->name);
-        change_link_placeholder_to_real_ID_pointer(mainlist, basefd, id, NULL);
-        BLI_freelinkN(lbarray[a], id);
-      }
-      id = id_next;
-    }
-  }
-}
-
-static FileData *read_library_file_data(FileData *basefd,
-                                        ListBase *mainlist,
-                                        Main *mainl,
-                                        Main *mainptr)
-{
-  FileData *fd = mainptr->curlib->filedata;
-
-  if (fd != NULL) {
-    /* File already open. */
-    return fd;
-  }
-
-  if (mainptr->curlib->packedfile) {
-    /* Read packed file. */
-    PackedFile *pf = mainptr->curlib->packedfile;
-
-    BLO_reportf_wrap(basefd->reports,
-                     RPT_INFO,
-                     TIP_("Read packed library:  '%s', parent '%s'"),
-                     mainptr->curlib->filepath,
-                     library_parent_filepath(mainptr->curlib));
-    fd = blo_filedata_from_memory(pf->data, pf->size, basefd->reports);
-
-    /* Needed for library_append and read_libraries. */
-    BLI_strncpy(fd->relabase, mainptr->curlib->filepath_abs, sizeof(fd->relabase));
-  }
-  else {
-    /* Read file on disk. */
-    BLO_reportf_wrap(basefd->reports,
-                     RPT_INFO,
-                     TIP_("Read library:  '%s', '%s', parent '%s'"),
-                     mainptr->curlib->filepath_abs,
-                     mainptr->curlib->filepath,
-                     library_parent_filepath(mainptr->curlib));
-    fd = blo_filedata_from_file(mainptr->curlib->filepath_abs, basefd->reports);
-  }
-
-  if (fd) {
-    /* Share the mainlist, so all libraries are added immediately in a
-     * single list. It used to be that all FileData's had their own list,
-     * but with indirectly linking this meant we didn't catch duplicate
-     * libraries properly. */
-    fd->mainlist = mainlist;
-
-    fd->reports = basefd->reports;
-
-    if (fd->libmap) {
-      oldnewmap_free(fd->libmap);
-    }
-
-    fd->libmap = oldnewmap_new();
-
-    mainptr->curlib->filedata = fd;
-    mainptr->versionfile = fd->fileversion;
-
-    /* subversion */
-    read_file_version(fd, mainptr);
-#ifdef USE_GHASH_BHEAD
-    read_file_bhead_idname_map_create(fd);
-#endif
-  }
-  else {
-    mainptr->curlib->filedata = NULL;
-    mainptr->curlib->id.tag |= LIB_TAG_MISSING;
-    /* Set lib version to current main one... Makes assert later happy. */
-    mainptr->versionfile = mainptr->curlib->versionfile = mainl->versionfile;
-    mainptr->subversionfile = mainptr->curlib->subversionfile = mainl->subversionfile;
-  }
-
-  if (fd == NULL) {
-    BLO_reportf_wrap(
-        basefd->reports, RPT_INFO, TIP_("Cannot find lib '%s'"), mainptr->curlib->filepath_abs);
-    basefd->reports->count.missing_libraries++;
-  }
-
-  return fd;
-}
-
-static void read_libraries(FileData *basefd, ListBase *mainlist)
-{
-  Main *mainl = mainlist->first;
-  bool do_it = true;
-
-  /* Expander is now callback function. */
-  BLO_main_expander(expand_doit_library);
-
-  /* At this point the base blend file has been read, and each library blend
-   * encountered so far has a main with placeholders for linked data-blocks.
-   *
-   * Now we will read the library blend files and replace the placeholders
-   * with actual data-blocks. We loop over library mains multiple times in
-   * case a library needs to link additional data-blocks from another library
-   * that had been read previously. */
-  while (do_it) {
-    do_it = false;
-
-    /* Loop over mains of all library blend files encountered so far. Note
-     * this list gets longer as more indirectly library blends are found. */
-    for (Main *mainptr = mainl->next; mainptr; mainptr = mainptr->next) {
-      /* Does this library have any more linked data-blocks we need to read? */
-      if (has_linked_ids_to_read(mainptr)) {
-        CLOG_INFO(&LOG,
-                  3,
-                  "Reading linked data-blocks from %s (%s)",
-                  mainptr->curlib->id.name,
-                  mainptr->curlib->filepath);
-
-        /* Open file if it has not been done yet. */
-        FileData *fd = read_library_file_data(basefd, mainlist, mainl, mainptr);
-
-        if (fd) {
-          do_it = true;
-
-          if (mainptr->id_map == NULL) {
-            mainptr->id_map = BKE_main_idmap_create(mainptr, false, NULL, MAIN_IDMAP_TYPE_NAME);
-          }
-        }
-
-        /* Read linked data-locks for each link placeholder, and replace
-         * the placeholder with the real data-lock. */
-        read_library_linked_ids(basefd, fd, mainlist, mainptr);
-
-        /* Test if linked data-locks need to read further linked data-locks
-         * and create link placeholders for them. */
-        BLO_expand_main(fd, mainptr);
-      }
-    }
-  }
-
-  Main *main_newid = BKE_main_new();
-  for (Main *mainptr = mainl->next; mainptr; mainptr = mainptr->next) {
-    /* Drop weak links for which no data-block was found. */
-    read_library_clear_weak_links(basefd, mainlist, mainptr);
-
-    /* Do versioning for newly added linked data-locks. If no data-locks
-     * were read from a library versionfile will still be zero and we can
-     * skip it. */
-    if (mainptr->versionfile) {
-      /* Split out already existing IDs to avoid them going through
-       * do_versions multiple times, which would have bad consequences. */
-      split_main_newid(mainptr, main_newid);
-
-      /* File data can be zero with link/append. */
-      if (mainptr->curlib->filedata) {
-        do_versions(mainptr->curlib->filedata, mainptr->curlib, main_newid);
-      }
-      else {
-        do_versions(basefd, NULL, main_newid);
-      }
-
-      add_main_to_main(mainptr, main_newid);
-    }
-
-    /* Lib linking. */
-    if (mainptr->curlib->filedata) {
-      lib_link_all(mainptr->curlib->filedata, mainptr);
-    }
-
-    /* NOTE: No need to call #do_versions_after_linking() or #BKE_main_id_refcount_recompute()
-     * here, as this function is only called for library 'subset' data handling, as part of
-     * either full blendfile reading (#blo_read_file_internal()), or library-data linking
-     * (#library_link_end()). */
-
-    /* Free file data we no longer need. */
-    if (mainptr->curlib->filedata) {
-      blo_filedata_free(mainptr->curlib->filedata);
-    }
-    mainptr->curlib->filedata = NULL;
-  }
-  BKE_main_free(main_newid);
-}
-
-void *BLO_read_get_new_data_address(BlendDataReader *reader, const void *old_address)
-{
-  return newdataadr(reader->fd, old_address);
-}
-
-void *BLO_read_get_new_data_address_no_us(BlendDataReader *reader, const void *old_address)
-{
-  return newdataadr_no_us(reader->fd, old_address);
-}
-
-void *BLO_read_get_new_packed_address(BlendDataReader *reader, const void *old_address)
-{
-  return newpackedadr(reader->fd, old_address);
-}
-
-ID *BLO_read_get_new_id_address(BlendLibReader *reader, Library *lib, ID *id)
-{
-  return newlibadr(reader->fd, lib, id);
-}
-
-bool BLO_read_requires_endian_switch(BlendDataReader *reader)
-{
-  return (reader->fd->flags & FD_FLAGS_SWITCH_ENDIAN) != 0;
-}
-
-void BLO_read_list_cb(BlendDataReader *reader, ListBase *list, BlendReadListFn callback)
-{
-  if (BLI_listbase_is_empty(list)) {
-    return;
-  }
-
-  BLO_read_data_address(reader, &list->first);
-  if (callback != NULL) {
-    callback(reader, list->first);
-  }
-  Link *ln = list->first;
-  Link *prev = NULL;
-  while (ln) {
-    BLO_read_data_address(reader, &ln->next);
-    if (ln->next != NULL && callback != NULL) {
-      callback(reader, ln->next);
-    }
-    ln->prev = prev;
-    prev = ln;
-    ln = ln->next;
-  }
-  list->last = prev;
-}
-
-void BLO_read_list(BlendDataReader *reader, struct ListBase *list)
-{
-  BLO_read_list_cb(reader, list, NULL);
-}
-
-void BLO_read_int32_array(BlendDataReader *reader, int array_size, int32_t **ptr_p)
-{
-  BLO_read_data_address(reader, ptr_p);
-  if (BLO_read_requires_endian_switch(reader)) {
-    BLI_endian_switch_int32_array(*ptr_p, array_size);
-  }
-}
-
-void BLO_read_uint32_array(BlendDataReader *reader, int array_size, uint32_t **ptr_p)
-{
-  BLO_read_data_address(reader, ptr_p);
-  if (BLO_read_requires_endian_switch(reader)) {
-    BLI_endian_switch_uint32_array(*ptr_p, array_size);
-  }
-}
-
-void BLO_read_float_array(BlendDataReader *reader, int array_size, float **ptr_p)
-{
-  BLO_read_data_address(reader, ptr_p);
-  if (BLO_read_requires_endian_switch(reader)) {
-    BLI_endian_switch_float_array(*ptr_p, array_size);
-  }
-}
-
-void BLO_read_float3_array(BlendDataReader *reader, int array_size, float **ptr_p)
-{
-  BLO_read_float_array(reader, array_size * 3, ptr_p);
-}
-
-void BLO_read_double_array(BlendDataReader *reader, int array_size, double **ptr_p)
-{
-  BLO_read_data_address(reader, ptr_p);
-  if (BLO_read_requires_endian_switch(reader)) {
-    BLI_endian_switch_double_array(*ptr_p, array_size);
-  }
-}
-
-static void convert_pointer_array_64_to_32(BlendDataReader *reader,
-                                           uint array_size,
-                                           const uint64_t *src,
-                                           uint32_t *dst)
-{
-  /* Match pointer conversion rules from bh4_from_bh8 and cast_pointer. */
-  if (BLO_read_requires_endian_switch(reader)) {
-    for (int i = 0; i < array_size; i++) {
-      uint64_t ptr = src[i];
-      BLI_endian_switch_uint64(&ptr);
-      dst[i] = (uint32_t)(ptr >> 3);
-    }
-  }
-  else {
-    for (int i = 0; i < array_size; i++) {
-      dst[i] = (uint32_t)(src[i] >> 3);
-    }
-  }
-}
-
-static void convert_pointer_array_32_to_64(BlendDataReader *UNUSED(reader),
-                                           uint array_size,
-                                           const uint32_t *src,
-                                           uint64_t *dst)
-{
-  /* Match pointer conversion rules from bh8_from_bh4 and cast_pointer_32_to_64. */
-  for (int i = 0; i < array_size; i++) {
-    dst[i] = src[i];
-  }
-}
-
-void BLO_read_pointer_array(BlendDataReader *reader, void **ptr_p)
-{
-  FileData *fd = reader->fd;
-
-  void *orig_array = newdataadr(fd, *ptr_p);
-  if (orig_array == NULL) {
-    *ptr_p = NULL;
-    return;
-  }
-
-  int file_pointer_size = fd->filesdna->pointer_size;
-  int current_pointer_size = fd->memsdna->pointer_size;
-
-  /* Over-allocation is fine, but might be better to pass the length as parameter. */
-  int array_size = MEM_allocN_len(orig_array) / file_pointer_size;
-
-  void *final_array = NULL;
-
-  if (file_pointer_size == current_pointer_size) {
-    /* No pointer conversion necessary. */
-    final_array = orig_array;
-  }
-  else if (file_pointer_size == 8 && current_pointer_size == 4) {
-    /* Convert pointers from 64 to 32 bit. */
-    final_array = MEM_malloc_arrayN(array_size, 4, "new pointer array");
-    convert_pointer_array_64_to_32(
-        reader, array_size, (uint64_t *)orig_array, (uint32_t *)final_array);
-    MEM_freeN(orig_array);
-  }
-  else if (file_pointer_size == 4 && current_pointer_size == 8) {
-    /* Convert pointers from 32 to 64 bit. */
-    final_array = MEM_malloc_arrayN(array_size, 8, "new pointer array");
-    convert_pointer_array_32_to_64(
-        reader, array_size, (uint32_t *)orig_array, (uint64_t *)final_array);
-    MEM_freeN(orig_array);
-  }
-  else {
-    BLI_assert(false);
-  }
-
-  *ptr_p = final_array;
-}
-
-bool BLO_read_data_is_undo(BlendDataReader *reader)
-{
-  return (reader->fd->flags & FD_FLAGS_IS_MEMFILE);
-}
-
-void BLO_read_data_globmap_add(BlendDataReader *reader, void *oldaddr, void *newaddr)
-{
-  oldnewmap_insert(reader->fd->globmap, oldaddr, newaddr, 0);
-}
-
-void BLO_read_glob_list(BlendDataReader *reader, ListBase *list)
-{
-  link_glob_list(reader->fd, list);
-}
-
-BlendFileReadReport *BLO_read_data_reports(BlendDataReader *reader)
-{
-  return reader->fd->reports;
-}
-
-bool BLO_read_lib_is_undo(BlendLibReader *reader)
-{
-  return (reader->fd->flags & FD_FLAGS_IS_MEMFILE);
-}
-
-Main *BLO_read_lib_get_main(BlendLibReader *reader)
-{
-  return reader->main;
-}
-
-BlendFileReadReport *BLO_read_lib_reports(BlendLibReader *reader)
-{
-  return reader->fd->reports;
-}
-
-void BLO_expand_id(BlendExpander *expander, ID *id)
-{
-  expand_doit(expander->fd, expander->main, id);
-}
-
-/** \} */
diff --git a/source/blender/blenloader/intern/readfile.cc b/source/blender/blenloader/intern/readfile.cc
new file mode 100644
index 00000000000..71708c09c01
--- /dev/null
+++ b/source/blender/blenloader/intern/readfile.cc
@@ -0,0 +1,5211 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright 2001-2002 NaN Holding BV. All rights reserved. */
+
+/** \file
+ * \ingroup blenloader
+ */
+
+#include  /* for isdigit. */
+#include  /* for open flags (O_BINARY, O_RDONLY). */
+#include 
+#include  /* for va_start/end. */
+#include  /* for offsetof. */
+#include  /* for atoi. */
+#include    /* for gmtime. */
+
+#include "BLI_utildefines.h"
+#ifndef WIN32
+#  include  /* for read close */
+#else
+#  include "BLI_winstuff.h"
+#  include "winsock2.h"
+#  include  /* for open close read */
+#endif
+
+#include "CLG_log.h"
+
+/* allow readfile to use deprecated functionality */
+#define DNA_DEPRECATED_ALLOW
+
+#include "DNA_anim_types.h"
+#include "DNA_asset_types.h"
+#include "DNA_cachefile_types.h"
+#include "DNA_collection_types.h"
+#include "DNA_fileglobal_types.h"
+#include "DNA_genfile.h"
+#include "DNA_key_types.h"
+#include "DNA_layer_types.h"
+#include "DNA_node_types.h"
+#include "DNA_packedFile_types.h"
+#include "DNA_sdna_types.h"
+#include "DNA_sound_types.h"
+#include "DNA_vfont_types.h"
+#include "DNA_volume_types.h"
+#include "DNA_workspace_types.h"
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_blenlib.h"
+#include "BLI_endian_defines.h"
+#include "BLI_endian_switch.h"
+#include "BLI_ghash.h"
+#include "BLI_linklist.h"
+#include "BLI_math.h"
+#include "BLI_memarena.h"
+#include "BLI_mempool.h"
+#include "BLI_threads.h"
+
+#include "PIL_time.h"
+
+#include "BLT_translation.h"
+
+#include "BKE_anim_data.h"
+#include "BKE_animsys.h"
+#include "BKE_asset.h"
+#include "BKE_collection.h"
+#include "BKE_global.h" /* for G */
+#include "BKE_idprop.h"
+#include "BKE_idtype.h"
+#include "BKE_layer.h"
+#include "BKE_lib_id.h"
+#include "BKE_lib_override.h"
+#include "BKE_lib_query.h"
+#include "BKE_main.h" /* for Main */
+#include "BKE_main_idmap.h"
+#include "BKE_material.h"
+#include "BKE_mesh.h"
+#include "BKE_modifier.h"
+#include "BKE_node.h" /* for tree type defines */
+#include "BKE_object.h"
+#include "BKE_packedFile.h"
+#include "BKE_report.h"
+#include "BKE_scene.h"
+#include "BKE_screen.h"
+#include "BKE_undo_system.h"
+#include "BKE_workspace.h"
+
+#include "DRW_engine.h"
+
+#include "DEG_depsgraph.h"
+
+#include "BLO_blend_defs.h"
+#include "BLO_blend_validate.h"
+#include "BLO_read_write.h"
+#include "BLO_readfile.h"
+#include "BLO_undofile.h"
+
+#include "SEQ_clipboard.h"
+#include "SEQ_iterator.h"
+#include "SEQ_modifier.h"
+#include "SEQ_sequencer.h"
+#include "SEQ_utils.h"
+
+#include "readfile.h"
+
+#include 
+
+/* Make preferences read-only. */
+#define U (*((const UserDef *)&U))
+
+/**
+ * READ
+ * ====
+ *
+ * - Existing Library (#Main) push or free
+ * - allocate new #Main
+ * - load file
+ * - read #SDNA
+ * - for each LibBlock
+ *   - read LibBlock
+ *   - if a Library
+ *     - make a new #Main
+ *     - attach ID's to it
+ *   - else
+ *     - read associated 'direct data'
+ *     - link direct data (internal and to LibBlock)
+ * - read #FileGlobal
+ * - read #USER data, only when indicated (file is `~/.config/blender/X.XX/config/userpref.blend`)
+ * - free file
+ * - per Library (per #Main)
+ *   - read file
+ *   - read #SDNA
+ *   - find LibBlocks and attach #ID's to #Main
+ *     - if external LibBlock
+ *       - search all #Main's
+ *         - or it's already read,
+ *         - or not read yet
+ *         - or make new #Main
+ *   - per LibBlock
+ *     - read recursive
+ *     - read associated direct data
+ *     - link direct data (internal and to LibBlock)
+ *   - free file
+ * - per Library with unread LibBlocks
+ *   - read file
+ *   - read #SDNA
+ *   - per LibBlock
+ *     - read recursive
+ *     - read associated direct data
+ *     - link direct data (internal and to LibBlock)
+ *   - free file
+ * - join all #Main's
+ * - link all LibBlocks and indirect pointers to libblocks
+ * - initialize #FileGlobal and copy pointers to #Global
+ *
+ * \note Still a weak point is the new-address function, that doesn't solve reading from
+ * multiple files at the same time.
+ * (added remark: oh, i thought that was solved? will look at that... (ton).
+ */
+
+/**
+ * Delay reading blocks we might not use (especially applies to library linking).
+ * which keeps large arrays in memory from data-blocks we may not even use.
+ *
+ * \note This is disabled when using compression,
+ * while ZLIB supports seek it's unusably slow, see: T61880.
+ */
+#define USE_BHEAD_READ_ON_DEMAND
+
+/** Use #GHash for #BHead name-based lookups (speeds up linking). */
+#define USE_GHASH_BHEAD
+
+/** Use #GHash for restoring pointers by name. */
+#define USE_GHASH_RESTORE_POINTER
+
+static CLG_LogRef LOG = {"blo.readfile"};
+static CLG_LogRef LOG_UNDO = {"blo.readfile.undo"};
+
+/* local prototypes */
+static void read_libraries(FileData *basefd, ListBase *mainlist);
+static void *read_struct(FileData *fd, BHead *bh, const char *blockname);
+static BHead *find_bhead_from_code_name(FileData *fd, const short idcode, const char *name);
+static BHead *find_bhead_from_idname(FileData *fd, const char *idname);
+
+typedef struct BHeadN {
+  struct BHeadN *next, *prev;
+#ifdef USE_BHEAD_READ_ON_DEMAND
+  /** Use to read the data from the file directly into memory as needed. */
+  off64_t file_offset;
+  /** When set, the remainder of this allocation is the data, otherwise it needs to be read. */
+  bool has_data;
+#endif
+  bool is_memchunk_identical;
+  struct BHead bhead;
+} BHeadN;
+
+#define BHEADN_FROM_BHEAD(bh) ((BHeadN *)POINTER_OFFSET(bh, -(int)offsetof(BHeadN, bhead)))
+
+/**
+ * We could change this in the future, for now it's simplest if only data is delayed
+ * because ID names are used in lookup tables.
+ */
+#define BHEAD_USE_READ_ON_DEMAND(bhead) ((bhead)->code == DATA)
+
+void BLO_reportf_wrap(BlendFileReadReport *reports, eReportType type, const char *format, ...)
+{
+  char fixed_buf[1024]; /* should be long enough */
+
+  va_list args;
+
+  va_start(args, format);
+  vsnprintf(fixed_buf, sizeof(fixed_buf), format, args);
+  va_end(args);
+
+  fixed_buf[sizeof(fixed_buf) - 1] = '\0';
+
+  BKE_report(reports->reports, type, fixed_buf);
+
+  if (G.background == 0) {
+    printf("%s: %s\n", BKE_report_type_str(type), fixed_buf);
+  }
+}
+
+/* for reporting linking messages */
+static const char *library_parent_filepath(Library *lib)
+{
+  return lib->parent ? lib->parent->filepath_abs : "";
+}
+
+/* -------------------------------------------------------------------- */
+/** \name OldNewMap API
+ * \{ */
+
+typedef struct OldNew {
+  const void *oldp;
+  void *newp;
+  /* `nr` is "user count" for data, and ID code for libdata. */
+  int nr;
+} OldNew;
+
+typedef struct OldNewMap {
+  /* Array that stores the actual entries. */
+  OldNew *entries;
+  int nentries;
+  /* Hash-map that stores indices into the `entries` array. */
+  int32_t *map;
+
+  int capacity_exp;
+} OldNewMap;
+
+#define ENTRIES_CAPACITY(onm) (1ll << (onm)->capacity_exp)
+#define MAP_CAPACITY(onm) (1ll << ((onm)->capacity_exp + 1))
+#define SLOT_MASK(onm) (MAP_CAPACITY(onm) - 1)
+#define DEFAULT_SIZE_EXP 6
+#define PERTURB_SHIFT 5
+
+/* based on the probing algorithm used in Python dicts. */
+#define ITER_SLOTS(onm, KEY, SLOT_NAME, INDEX_NAME) \
+  uint32_t hash = BLI_ghashutil_ptrhash(KEY); \
+  uint32_t mask = SLOT_MASK(onm); \
+  uint perturb = hash; \
+  int SLOT_NAME = mask & hash; \
+  int INDEX_NAME = onm->map[SLOT_NAME]; \
+  for (;; SLOT_NAME = mask & ((5 * SLOT_NAME) + 1 + perturb), \
+          perturb >>= PERTURB_SHIFT, \
+          INDEX_NAME = onm->map[SLOT_NAME])
+
+static void oldnewmap_insert_index_in_map(OldNewMap *onm, const void *ptr, int index)
+{
+  ITER_SLOTS (onm, ptr, slot, stored_index) {
+    if (stored_index == -1) {
+      onm->map[slot] = index;
+      break;
+    }
+  }
+}
+
+static void oldnewmap_insert_or_replace(OldNewMap *onm, OldNew entry)
+{
+  ITER_SLOTS (onm, entry.oldp, slot, index) {
+    if (index == -1) {
+      onm->entries[onm->nentries] = entry;
+      onm->map[slot] = onm->nentries;
+      onm->nentries++;
+      break;
+    }
+    if (onm->entries[index].oldp == entry.oldp) {
+      onm->entries[index] = entry;
+      break;
+    }
+  }
+}
+
+static OldNew *oldnewmap_lookup_entry(const OldNewMap *onm, const void *addr)
+{
+  ITER_SLOTS (onm, addr, slot, index) {
+    if (index >= 0) {
+      OldNew *entry = &onm->entries[index];
+      if (entry->oldp == addr) {
+        return entry;
+      }
+    }
+    else {
+      return nullptr;
+    }
+  }
+}
+
+static void oldnewmap_clear_map(OldNewMap *onm)
+{
+  memset(onm->map, 0xFF, MAP_CAPACITY(onm) * sizeof(*onm->map));
+}
+
+static void oldnewmap_increase_size(OldNewMap *onm)
+{
+  onm->capacity_exp++;
+  onm->entries = static_cast(
+      MEM_reallocN(onm->entries, sizeof(*onm->entries) * ENTRIES_CAPACITY(onm)));
+  onm->map = static_cast(MEM_reallocN(onm->map, sizeof(*onm->map) * MAP_CAPACITY(onm)));
+  oldnewmap_clear_map(onm);
+  for (int i = 0; i < onm->nentries; i++) {
+    oldnewmap_insert_index_in_map(onm, onm->entries[i].oldp, i);
+  }
+}
+
+/* Public OldNewMap API */
+
+static void oldnewmap_init_data(OldNewMap *onm, const int capacity_exp)
+{
+  memset(onm, 0x0, sizeof(*onm));
+
+  onm->capacity_exp = capacity_exp;
+  onm->entries = static_cast(
+      MEM_malloc_arrayN(ENTRIES_CAPACITY(onm), sizeof(*onm->entries), "OldNewMap.entries"));
+  onm->map = static_cast(
+      MEM_malloc_arrayN(MAP_CAPACITY(onm), sizeof(*onm->map), "OldNewMap.map"));
+  oldnewmap_clear_map(onm);
+}
+
+static OldNewMap *oldnewmap_new(void)
+{
+  OldNewMap *onm = static_cast(MEM_mallocN(sizeof(*onm), "OldNewMap"));
+
+  oldnewmap_init_data(onm, DEFAULT_SIZE_EXP);
+
+  return onm;
+}
+
+static void oldnewmap_insert(OldNewMap *onm, const void *oldaddr, void *newaddr, int nr)
+{
+  if (oldaddr == nullptr || newaddr == nullptr) {
+    return;
+  }
+
+  if (UNLIKELY(onm->nentries == ENTRIES_CAPACITY(onm))) {
+    oldnewmap_increase_size(onm);
+  }
+
+  OldNew entry;
+  entry.oldp = oldaddr;
+  entry.newp = newaddr;
+  entry.nr = nr;
+  oldnewmap_insert_or_replace(onm, entry);
+}
+
+static void oldnewmap_lib_insert(FileData *fd, const void *oldaddr, ID *newaddr, int nr)
+{
+  oldnewmap_insert(fd->libmap, oldaddr, newaddr, nr);
+}
+
+void blo_do_versions_oldnewmap_insert(OldNewMap *onm, const void *oldaddr, void *newaddr, int nr)
+{
+  oldnewmap_insert(onm, oldaddr, newaddr, nr);
+}
+
+static void *oldnewmap_lookup_and_inc(OldNewMap *onm, const void *addr, bool increase_users)
+{
+  OldNew *entry = oldnewmap_lookup_entry(onm, addr);
+  if (entry == nullptr) {
+    return nullptr;
+  }
+  if (increase_users) {
+    entry->nr++;
+  }
+  return entry->newp;
+}
+
+/* for libdata, OldNew.nr has ID code, no increment */
+static void *oldnewmap_liblookup(OldNewMap *onm, const void *addr, const void *lib)
+{
+  if (addr == nullptr) {
+    return nullptr;
+  }
+
+  ID *id = static_cast(oldnewmap_lookup_and_inc(onm, addr, false));
+  if (id == nullptr) {
+    return nullptr;
+  }
+  if (!lib || id->lib) {
+    return id;
+  }
+  return nullptr;
+}
+
+static void oldnewmap_clear(OldNewMap *onm)
+{
+  /* Free unused data. */
+  for (int i = 0; i < onm->nentries; i++) {
+    OldNew *entry = &onm->entries[i];
+    if (entry->nr == 0) {
+      MEM_freeN(entry->newp);
+      entry->newp = nullptr;
+    }
+  }
+
+  MEM_freeN(onm->entries);
+  MEM_freeN(onm->map);
+
+  oldnewmap_init_data(onm, DEFAULT_SIZE_EXP);
+}
+
+static void oldnewmap_free(OldNewMap *onm)
+{
+  MEM_freeN(onm->entries);
+  MEM_freeN(onm->map);
+  MEM_freeN(onm);
+}
+
+#undef ENTRIES_CAPACITY
+#undef MAP_CAPACITY
+#undef SLOT_MASK
+#undef DEFAULT_SIZE_EXP
+#undef PERTURB_SHIFT
+#undef ITER_SLOTS
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Helper Functions
+ * \{ */
+
+static void add_main_to_main(Main *mainvar, Main *from)
+{
+  ListBase *lbarray[INDEX_ID_MAX], *fromarray[INDEX_ID_MAX];
+  int a;
+
+  set_listbasepointers(mainvar, lbarray);
+  a = set_listbasepointers(from, fromarray);
+  while (a--) {
+    BLI_movelisttolist(lbarray[a], fromarray[a]);
+  }
+}
+
+void blo_join_main(ListBase *mainlist)
+{
+  Main *tojoin, *mainl;
+
+  mainl = static_cast
(mainlist->first);
+
+  if (mainl->id_map != nullptr) {
+    /* Cannot keep this since we add some IDs from joined mains. */
+    BKE_main_idmap_destroy(mainl->id_map);
+    mainl->id_map = nullptr;
+  }
+
+  while ((tojoin = mainl->next)) {
+    add_main_to_main(mainl, tojoin);
+    BLI_remlink(mainlist, tojoin);
+    BKE_main_free(tojoin);
+  }
+}
+
+static void split_libdata(ListBase *lb_src, Main **lib_main_array, const uint lib_main_array_len)
+{
+  for (ID *id = static_cast(lb_src->first), *idnext; id; id = idnext) {
+    idnext = static_cast(id->next);
+
+    if (id->lib) {
+      if (((uint)id->lib->temp_index < lib_main_array_len) &&
+          /* this check should never fail, just in case 'id->lib' is a dangling pointer. */
+          (lib_main_array[id->lib->temp_index]->curlib == id->lib)) {
+        Main *mainvar = lib_main_array[id->lib->temp_index];
+        ListBase *lb_dst = which_libbase(mainvar, GS(id->name));
+        BLI_remlink(lb_src, id);
+        BLI_addtail(lb_dst, id);
+      }
+      else {
+        CLOG_ERROR(&LOG, "Invalid library for '%s'", id->name);
+      }
+    }
+  }
+}
+
+void blo_split_main(ListBase *mainlist, Main *main)
+{
+  mainlist->first = mainlist->last = main;
+  main->next = nullptr;
+
+  if (BLI_listbase_is_empty(&main->libraries)) {
+    return;
+  }
+
+  if (main->id_map != nullptr) {
+    /* Cannot keep this since we remove some IDs from given main. */
+    BKE_main_idmap_destroy(main->id_map);
+    main->id_map = nullptr;
+  }
+
+  /* (Library.temp_index -> Main), lookup table */
+  const uint lib_main_array_len = BLI_listbase_count(&main->libraries);
+  Main **lib_main_array = static_cast
(
+      MEM_malloc_arrayN(lib_main_array_len, sizeof(*lib_main_array), __func__));
+
+  int i = 0;
+  for (Library *lib = static_cast(main->libraries.first); lib;
+       lib = static_cast(lib->id.next), i++) {
+    Main *libmain = BKE_main_new();
+    libmain->curlib = lib;
+    libmain->versionfile = lib->versionfile;
+    libmain->subversionfile = lib->subversionfile;
+    BLI_addtail(mainlist, libmain);
+    lib->temp_index = i;
+    lib_main_array[i] = libmain;
+  }
+
+  ListBase *lbarray[INDEX_ID_MAX];
+  i = set_listbasepointers(main, lbarray);
+  while (i--) {
+    ID *id = static_cast(lbarray[i]->first);
+    if (id == nullptr || GS(id->name) == ID_LI) {
+      /* No ID_LI data-block should ever be linked anyway, but just in case, better be explicit. */
+      continue;
+    }
+    split_libdata(lbarray[i], lib_main_array, lib_main_array_len);
+  }
+
+  MEM_freeN(lib_main_array);
+}
+
+static void read_file_version(FileData *fd, Main *main)
+{
+  BHead *bhead;
+
+  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
+    if (bhead->code == GLOB) {
+      FileGlobal *fg = static_cast(read_struct(fd, bhead, "Global"));
+      if (fg) {
+        main->subversionfile = fg->subversion;
+        main->minversionfile = fg->minversion;
+        main->minsubversionfile = fg->minsubversion;
+        MEM_freeN(fg);
+      }
+      else if (bhead->code == ENDB) {
+        break;
+      }
+    }
+  }
+  if (main->curlib) {
+    main->curlib->versionfile = main->versionfile;
+    main->curlib->subversionfile = main->subversionfile;
+  }
+}
+
+static bool blo_bhead_is_id(const BHead *bhead)
+{
+  /* BHead codes are four bytes (like 'ENDB', 'TEST', etc.), but if the two most-significant bytes
+   * are zero, the values actually indicate an ID type. */
+  return bhead->code <= 0xFFFF;
+}
+
+static bool blo_bhead_is_id_valid_type(const BHead *bhead)
+{
+  if (!blo_bhead_is_id(bhead)) {
+    return false;
+  }
+
+  const short id_type_code = bhead->code & 0xFFFF;
+  return BKE_idtype_idcode_is_valid(id_type_code);
+}
+
+#ifdef USE_GHASH_BHEAD
+static void read_file_bhead_idname_map_create(FileData *fd)
+{
+  BHead *bhead;
+
+  /* dummy values */
+  bool is_link = false;
+  int code_prev = ENDB;
+  uint reserve = 0;
+
+  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
+    if (code_prev != bhead->code) {
+      code_prev = bhead->code;
+      is_link = blo_bhead_is_id_valid_type(bhead) ?
+                    BKE_idtype_idcode_is_linkable((short)code_prev) :
+                    false;
+    }
+
+    if (is_link) {
+      reserve += 1;
+    }
+  }
+
+  BLI_assert(fd->bhead_idname_hash == nullptr);
+
+  fd->bhead_idname_hash = BLI_ghash_str_new_ex(__func__, reserve);
+
+  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
+    if (code_prev != bhead->code) {
+      code_prev = bhead->code;
+      is_link = blo_bhead_is_id_valid_type(bhead) ?
+                    BKE_idtype_idcode_is_linkable((short)code_prev) :
+                    false;
+    }
+
+    if (is_link) {
+      BLI_ghash_insert(fd->bhead_idname_hash, (void *)blo_bhead_id_name(fd, bhead), bhead);
+    }
+  }
+}
+#endif
+
+static Main *blo_find_main(FileData *fd, const char *filepath, const char *relabase)
+{
+  ListBase *mainlist = fd->mainlist;
+  Main *m;
+  Library *lib;
+  char name1[FILE_MAX];
+
+  BLI_strncpy(name1, filepath, sizeof(name1));
+  BLI_path_normalize(relabase, name1);
+
+  //  printf("blo_find_main: relabase  %s\n", relabase);
+  //  printf("blo_find_main: original in  %s\n", filepath);
+  //  printf("blo_find_main: converted to %s\n", name1);
+
+  for (m = static_cast
(mainlist->first); m; m = m->next) {
+    const char *libname = (m->curlib) ? m->curlib->filepath_abs : m->filepath;
+
+    if (BLI_path_cmp(name1, libname) == 0) {
+      if (G.debug & G_DEBUG) {
+        CLOG_INFO(&LOG, 3, "Found library %s", libname);
+      }
+      return m;
+    }
+  }
+
+  m = BKE_main_new();
+  BLI_addtail(mainlist, m);
+
+  /* Add library data-block itself to 'main' Main, since libraries are **never** linked data.
+   * Fixes bug where you could end with all ID_LI data-blocks having the same name... */
+  lib = static_cast(BKE_libblock_alloc(
+      static_cast
(mainlist->first), ID_LI, BLI_path_basename(filepath), 0));
+
+  /* Important, consistency with main ID reading code from read_libblock(). */
+  lib->id.us = ID_FAKE_USERS(lib);
+
+  /* Matches direct_link_library(). */
+  id_us_ensure_real(&lib->id);
+
+  BLI_strncpy(lib->filepath, filepath, sizeof(lib->filepath));
+  BLI_strncpy(lib->filepath_abs, name1, sizeof(lib->filepath_abs));
+
+  m->curlib = lib;
+
+  read_file_version(fd, m);
+
+  if (G.debug & G_DEBUG) {
+    CLOG_INFO(&LOG, 3, "Added new lib %s", filepath);
+  }
+  return m;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name File Parsing
+ * \{ */
+
+typedef struct BlendDataReader {
+  FileData *fd;
+} BlendDataReader;
+
+typedef struct BlendLibReader {
+  FileData *fd;
+  Main *main;
+} BlendLibReader;
+
+typedef struct BlendExpander {
+  FileData *fd;
+  Main *main;
+} BlendExpander;
+
+static void switch_endian_bh4(BHead4 *bhead)
+{
+  /* the ID_.. codes */
+  if ((bhead->code & 0xFFFF) == 0) {
+    bhead->code >>= 16;
+  }
+
+  if (bhead->code != ENDB) {
+    BLI_endian_switch_int32(&bhead->len);
+    BLI_endian_switch_int32(&bhead->SDNAnr);
+    BLI_endian_switch_int32(&bhead->nr);
+  }
+}
+
+static void switch_endian_bh8(BHead8 *bhead)
+{
+  /* the ID_.. codes */
+  if ((bhead->code & 0xFFFF) == 0) {
+    bhead->code >>= 16;
+  }
+
+  if (bhead->code != ENDB) {
+    BLI_endian_switch_int32(&bhead->len);
+    BLI_endian_switch_int32(&bhead->SDNAnr);
+    BLI_endian_switch_int32(&bhead->nr);
+  }
+}
+
+static void bh4_from_bh8(BHead *bhead, BHead8 *bhead8, bool do_endian_swap)
+{
+  BHead4 *bhead4 = (BHead4 *)bhead;
+  int64_t old;
+
+  bhead4->code = bhead8->code;
+  bhead4->len = bhead8->len;
+
+  if (bhead4->code != ENDB) {
+    /* perform a endian swap on 64bit pointers, otherwise the pointer might map to zero
+     * 0x0000000000000000000012345678 would become 0x12345678000000000000000000000000
+     */
+    if (do_endian_swap) {
+      BLI_endian_switch_uint64(&bhead8->old);
+    }
+
+    /* this patch is to avoid `intptr_t` being read from not-eight aligned positions
+     * is necessary on any modern 64bit architecture) */
+    memcpy(&old, &bhead8->old, 8);
+    bhead4->old = (int)(old >> 3);
+
+    bhead4->SDNAnr = bhead8->SDNAnr;
+    bhead4->nr = bhead8->nr;
+  }
+}
+
+static void bh8_from_bh4(BHead *bhead, BHead4 *bhead4)
+{
+  BHead8 *bhead8 = (BHead8 *)bhead;
+
+  bhead8->code = bhead4->code;
+  bhead8->len = bhead4->len;
+
+  if (bhead8->code != ENDB) {
+    bhead8->old = bhead4->old;
+    bhead8->SDNAnr = bhead4->SDNAnr;
+    bhead8->nr = bhead4->nr;
+  }
+}
+
+static BHeadN *get_bhead(FileData *fd)
+{
+  BHeadN *new_bhead = nullptr;
+  ssize_t readsize;
+
+  if (fd) {
+    if (!fd->is_eof) {
+      /* initializing to zero isn't strictly needed but shuts valgrind up
+       * since uninitialized memory gets compared */
+      BHead8 bhead8 = {0};
+      BHead4 bhead4 = {0};
+      BHead bhead = {0};
+
+      /* First read the bhead structure.
+       * Depending on the platform the file was written on this can
+       * be a big or little endian BHead4 or BHead8 structure.
+       *
+       * As usual 'ENDB' (the last *partial* bhead of the file)
+       * needs some special handling. We don't want to EOF just yet.
+       */
+      if (fd->flags & FD_FLAGS_FILE_POINTSIZE_IS_4) {
+        bhead4.code = DATA;
+        readsize = fd->file->read(fd->file, &bhead4, sizeof(bhead4));
+
+        if (readsize == sizeof(bhead4) || bhead4.code == ENDB) {
+          if (fd->flags & FD_FLAGS_SWITCH_ENDIAN) {
+            switch_endian_bh4(&bhead4);
+          }
+
+          if (fd->flags & FD_FLAGS_POINTSIZE_DIFFERS) {
+            bh8_from_bh4(&bhead, &bhead4);
+          }
+          else {
+            /* MIN2 is only to quiet '-Warray-bounds' compiler warning. */
+            BLI_assert(sizeof(bhead) == sizeof(bhead4));
+            memcpy(&bhead, &bhead4, MIN2(sizeof(bhead), sizeof(bhead4)));
+          }
+        }
+        else {
+          fd->is_eof = true;
+          bhead.len = 0;
+        }
+      }
+      else {
+        bhead8.code = DATA;
+        readsize = fd->file->read(fd->file, &bhead8, sizeof(bhead8));
+
+        if (readsize == sizeof(bhead8) || bhead8.code == ENDB) {
+          if (fd->flags & FD_FLAGS_SWITCH_ENDIAN) {
+            switch_endian_bh8(&bhead8);
+          }
+
+          if (fd->flags & FD_FLAGS_POINTSIZE_DIFFERS) {
+            bh4_from_bh8(&bhead, &bhead8, (fd->flags & FD_FLAGS_SWITCH_ENDIAN) != 0);
+          }
+          else {
+            /* MIN2 is only to quiet '-Warray-bounds' compiler warning. */
+            BLI_assert(sizeof(bhead) == sizeof(bhead8));
+            memcpy(&bhead, &bhead8, MIN2(sizeof(bhead), sizeof(bhead8)));
+          }
+        }
+        else {
+          fd->is_eof = true;
+          bhead.len = 0;
+        }
+      }
+
+      /* make sure people are not trying to pass bad blend files */
+      if (bhead.len < 0) {
+        fd->is_eof = true;
+      }
+
+      /* bhead now contains the (converted) bhead structure. Now read
+       * the associated data and put everything in a BHeadN (creative naming !)
+       */
+      if (fd->is_eof) {
+        /* pass */
+      }
+#ifdef USE_BHEAD_READ_ON_DEMAND
+      else if (fd->file->seek != nullptr && BHEAD_USE_READ_ON_DEMAND(&bhead)) {
+        /* Delay reading bhead content. */
+        new_bhead = static_cast(MEM_mallocN(sizeof(BHeadN), "new_bhead"));
+        if (new_bhead) {
+          new_bhead->next = new_bhead->prev = nullptr;
+          new_bhead->file_offset = fd->file->offset;
+          new_bhead->has_data = false;
+          new_bhead->is_memchunk_identical = false;
+          new_bhead->bhead = bhead;
+          off64_t seek_new = fd->file->seek(fd->file, bhead.len, SEEK_CUR);
+          if (seek_new == -1) {
+            fd->is_eof = true;
+            MEM_freeN(new_bhead);
+            new_bhead = nullptr;
+          }
+          BLI_assert(fd->file->offset == seek_new);
+        }
+        else {
+          fd->is_eof = true;
+        }
+      }
+#endif
+      else {
+        new_bhead = static_cast(
+            MEM_mallocN(sizeof(BHeadN) + (size_t)bhead.len, "new_bhead"));
+        if (new_bhead) {
+          new_bhead->next = new_bhead->prev = nullptr;
+#ifdef USE_BHEAD_READ_ON_DEMAND
+          new_bhead->file_offset = 0; /* don't seek. */
+          new_bhead->has_data = true;
+#endif
+          new_bhead->is_memchunk_identical = false;
+          new_bhead->bhead = bhead;
+
+          readsize = fd->file->read(fd->file, new_bhead + 1, (size_t)bhead.len);
+
+          if (readsize != bhead.len) {
+            fd->is_eof = true;
+            MEM_freeN(new_bhead);
+            new_bhead = nullptr;
+          }
+
+          if (fd->flags & FD_FLAGS_IS_MEMFILE) {
+            new_bhead->is_memchunk_identical = ((UndoReader *)fd->file)->memchunk_identical;
+          }
+        }
+        else {
+          fd->is_eof = true;
+        }
+      }
+    }
+  }
+
+  /* We've read a new block. Now add it to the list
+   * of blocks.
+   */
+  if (new_bhead) {
+    BLI_addtail(&fd->bhead_list, new_bhead);
+  }
+
+  return new_bhead;
+}
+
+BHead *blo_bhead_first(FileData *fd)
+{
+  BHeadN *new_bhead;
+  BHead *bhead = nullptr;
+
+  /* Rewind the file
+   * Read in a new block if necessary
+   */
+  new_bhead = static_cast(fd->bhead_list.first);
+  if (new_bhead == nullptr) {
+    new_bhead = get_bhead(fd);
+  }
+
+  if (new_bhead) {
+    bhead = &new_bhead->bhead;
+  }
+
+  return bhead;
+}
+
+BHead *blo_bhead_prev(FileData *UNUSED(fd), BHead *thisblock)
+{
+  BHeadN *bheadn = BHEADN_FROM_BHEAD(thisblock);
+  BHeadN *prev = bheadn->prev;
+
+  return (prev) ? &prev->bhead : nullptr;
+}
+
+BHead *blo_bhead_next(FileData *fd, BHead *thisblock)
+{
+  BHeadN *new_bhead = nullptr;
+  BHead *bhead = nullptr;
+
+  if (thisblock) {
+    /* bhead is actually a sub part of BHeadN
+     * We calculate the BHeadN pointer from the BHead pointer below */
+    new_bhead = BHEADN_FROM_BHEAD(thisblock);
+
+    /* get the next BHeadN. If it doesn't exist we read in the next one */
+    new_bhead = new_bhead->next;
+    if (new_bhead == nullptr) {
+      new_bhead = get_bhead(fd);
+    }
+  }
+
+  if (new_bhead) {
+    /* here we do the reverse:
+     * go from the BHeadN pointer to the BHead pointer */
+    bhead = &new_bhead->bhead;
+  }
+
+  return bhead;
+}
+
+#ifdef USE_BHEAD_READ_ON_DEMAND
+static bool blo_bhead_read_data(FileData *fd, BHead *thisblock, void *buf)
+{
+  bool success = true;
+  BHeadN *new_bhead = BHEADN_FROM_BHEAD(thisblock);
+  BLI_assert(new_bhead->has_data == false && new_bhead->file_offset != 0);
+  off64_t offset_backup = fd->file->offset;
+  if (UNLIKELY(fd->file->seek(fd->file, new_bhead->file_offset, SEEK_SET) == -1)) {
+    success = false;
+  }
+  else {
+    if (fd->file->read(fd->file, buf, (size_t)new_bhead->bhead.len) != new_bhead->bhead.len) {
+      success = false;
+    }
+    if (fd->flags & FD_FLAGS_IS_MEMFILE) {
+      new_bhead->is_memchunk_identical = ((UndoReader *)fd->file)->memchunk_identical;
+    }
+  }
+  if (fd->file->seek(fd->file, offset_backup, SEEK_SET) == -1) {
+    success = false;
+  }
+  return success;
+}
+
+static BHead *blo_bhead_read_full(FileData *fd, BHead *thisblock)
+{
+  BHeadN *new_bhead = BHEADN_FROM_BHEAD(thisblock);
+  BHeadN *new_bhead_data = static_cast(
+      MEM_mallocN(sizeof(BHeadN) + new_bhead->bhead.len, "new_bhead"));
+  new_bhead_data->bhead = new_bhead->bhead;
+  new_bhead_data->file_offset = new_bhead->file_offset;
+  new_bhead_data->has_data = true;
+  new_bhead_data->is_memchunk_identical = false;
+  if (!blo_bhead_read_data(fd, thisblock, new_bhead_data + 1)) {
+    MEM_freeN(new_bhead_data);
+    return nullptr;
+  }
+  return &new_bhead_data->bhead;
+}
+#endif /* USE_BHEAD_READ_ON_DEMAND */
+
+const char *blo_bhead_id_name(const FileData *fd, const BHead *bhead)
+{
+  return (const char *)POINTER_OFFSET(bhead, sizeof(*bhead) + fd->id_name_offset);
+}
+
+AssetMetaData *blo_bhead_id_asset_data_address(const FileData *fd, const BHead *bhead)
+{
+  BLI_assert(blo_bhead_is_id_valid_type(bhead));
+  return (fd->id_asset_data_offset >= 0) ?
+             *(AssetMetaData **)POINTER_OFFSET(bhead, sizeof(*bhead) + fd->id_asset_data_offset) :
+             nullptr;
+}
+
+static void decode_blender_header(FileData *fd)
+{
+  char header[SIZEOFBLENDERHEADER], num[4];
+  ssize_t readsize;
+
+  /* read in the header data */
+  readsize = fd->file->read(fd->file, header, sizeof(header));
+
+  if (readsize == sizeof(header) && STREQLEN(header, "BLENDER", 7) && ELEM(header[7], '_', '-') &&
+      ELEM(header[8], 'v', 'V') &&
+      (isdigit(header[9]) && isdigit(header[10]) && isdigit(header[11]))) {
+    fd->flags |= FD_FLAGS_FILE_OK;
+
+    /* what size are pointers in the file ? */
+    if (header[7] == '_') {
+      fd->flags |= FD_FLAGS_FILE_POINTSIZE_IS_4;
+      if (sizeof(void *) != 4) {
+        fd->flags |= FD_FLAGS_POINTSIZE_DIFFERS;
+      }
+    }
+    else {
+      if (sizeof(void *) != 8) {
+        fd->flags |= FD_FLAGS_POINTSIZE_DIFFERS;
+      }
+    }
+
+    /* is the file saved in a different endian
+     * than we need ?
+     */
+    if (((header[8] == 'v') ? L_ENDIAN : B_ENDIAN) != ENDIAN_ORDER) {
+      fd->flags |= FD_FLAGS_SWITCH_ENDIAN;
+    }
+
+    /* get the version number */
+    memcpy(num, header + 9, 3);
+    num[3] = 0;
+    fd->fileversion = atoi(num);
+  }
+}
+
+/**
+ * \return Success if the file is read correctly, else set \a r_error_message.
+ */
+static bool read_file_dna(FileData *fd, const char **r_error_message)
+{
+  BHead *bhead;
+  int subversion = 0;
+
+  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
+    if (bhead->code == GLOB) {
+      /* Before this, the subversion didn't exist in 'FileGlobal' so the subversion
+       * value isn't accessible for the purpose of DNA versioning in this case. */
+      if (fd->fileversion <= 242) {
+        continue;
+      }
+      /* We can't use read_global because this needs 'DNA1' to be decoded,
+       * however the first 4 chars are _always_ the subversion. */
+      FileGlobal *fg = reinterpret_cast(&bhead[1]);
+      BLI_STATIC_ASSERT(offsetof(FileGlobal, subvstr) == 0, "Must be first: subvstr")
+      char num[5];
+      memcpy(num, fg->subvstr, 4);
+      num[4] = 0;
+      subversion = atoi(num);
+    }
+    else if (bhead->code == DNA1) {
+      const bool do_endian_swap = (fd->flags & FD_FLAGS_SWITCH_ENDIAN) != 0;
+
+      fd->filesdna = DNA_sdna_from_data(
+          &bhead[1], bhead->len, do_endian_swap, true, r_error_message);
+      if (fd->filesdna) {
+        blo_do_versions_dna(fd->filesdna, fd->fileversion, subversion);
+        fd->compflags = DNA_struct_get_compareflags(fd->filesdna, fd->memsdna);
+        fd->reconstruct_info = DNA_reconstruct_info_create(
+            fd->filesdna, fd->memsdna, fd->compflags);
+        /* used to retrieve ID names from (bhead+1) */
+        fd->id_name_offset = DNA_elem_offset(fd->filesdna, "ID", "char", "name[]");
+        BLI_assert(fd->id_name_offset != -1);
+        fd->id_asset_data_offset = DNA_elem_offset(
+            fd->filesdna, "ID", "AssetMetaData", "*asset_data");
+
+        return true;
+      }
+
+      return false;
+    }
+    else if (bhead->code == ENDB) {
+      break;
+    }
+  }
+
+  *r_error_message = "Missing DNA block";
+  return false;
+}
+
+static int *read_file_thumbnail(FileData *fd)
+{
+  BHead *bhead;
+  int *blend_thumb = nullptr;
+
+  for (bhead = blo_bhead_first(fd); bhead; bhead = blo_bhead_next(fd, bhead)) {
+    if (bhead->code == TEST) {
+      const bool do_endian_swap = (fd->flags & FD_FLAGS_SWITCH_ENDIAN) != 0;
+      int *data = (int *)(bhead + 1);
+
+      if (bhead->len < (sizeof(int[2]))) {
+        break;
+      }
+
+      if (do_endian_swap) {
+        BLI_endian_switch_int32(&data[0]);
+        BLI_endian_switch_int32(&data[1]);
+      }
+
+      const int width = data[0];
+      const int height = data[1];
+      if (!BLEN_THUMB_MEMSIZE_IS_VALID(width, height)) {
+        break;
+      }
+      if (bhead->len < BLEN_THUMB_MEMSIZE_FILE(width, height)) {
+        break;
+      }
+
+      blend_thumb = data;
+      break;
+    }
+    if (bhead->code != REND) {
+      /* Thumbnail is stored in TEST immediately after first REND... */
+      break;
+    }
+  }
+
+  return blend_thumb;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name File Data API
+ * \{ */
+
+static FileData *filedata_new(BlendFileReadReport *reports)
+{
+  BLI_assert(reports != nullptr);
+
+  FileData *fd = static_cast(MEM_callocN(sizeof(FileData), "FileData"));
+
+  fd->memsdna = DNA_sdna_current_get();
+
+  fd->datamap = oldnewmap_new();
+  fd->globmap = oldnewmap_new();
+  fd->libmap = oldnewmap_new();
+
+  fd->reports = reports;
+
+  return fd;
+}
+
+static FileData *blo_decode_and_check(FileData *fd, ReportList *reports)
+{
+  decode_blender_header(fd);
+
+  if (fd->flags & FD_FLAGS_FILE_OK) {
+    const char *error_message = nullptr;
+    if (read_file_dna(fd, &error_message) == false) {
+      BKE_reportf(
+          reports, RPT_ERROR, "Failed to read blend file '%s': %s", fd->relabase, error_message);
+      blo_filedata_free(fd);
+      fd = nullptr;
+    }
+  }
+  else {
+    BKE_reportf(
+        reports, RPT_ERROR, "Failed to read blend file '%s', not a blend file", fd->relabase);
+    blo_filedata_free(fd);
+    fd = nullptr;
+  }
+
+  return fd;
+}
+
+static FileData *blo_filedata_from_file_descriptor(const char *filepath,
+                                                   BlendFileReadReport *reports,
+                                                   int filedes)
+{
+  char header[7];
+  FileReader *rawfile = BLI_filereader_new_file(filedes);
+  FileReader *file = nullptr;
+
+  errno = 0;
+  /* If opening the file failed or we can't read the header, give up. */
+  if (rawfile == nullptr || rawfile->read(rawfile, header, sizeof(header)) != sizeof(header)) {
+    BKE_reportf(reports->reports,
+                RPT_WARNING,
+                "Unable to read '%s': %s",
+                filepath,
+                errno ? strerror(errno) : TIP_("insufficient content"));
+    if (rawfile) {
+      rawfile->close(rawfile);
+    }
+    else {
+      close(filedes);
+    }
+    return nullptr;
+  }
+
+  /* Rewind the file after reading the header. */
+  rawfile->seek(rawfile, 0, SEEK_SET);
+
+  /* Check if we have a regular file. */
+  if (memcmp(header, "BLENDER", sizeof(header)) == 0) {
+    /* Try opening the file with memory-mapped IO. */
+    file = BLI_filereader_new_mmap(filedes);
+    if (file == nullptr) {
+      /* mmap failed, so just keep using rawfile. */
+      file = rawfile;
+      rawfile = nullptr;
+    }
+  }
+  else if (BLI_file_magic_is_gzip(header)) {
+    file = BLI_filereader_new_gzip(rawfile);
+    if (file != nullptr) {
+      rawfile = nullptr; /* The `Gzip` #FileReader takes ownership of `rawfile`. */
+    }
+  }
+  else if (BLI_file_magic_is_zstd(header)) {
+    file = BLI_filereader_new_zstd(rawfile);
+    if (file != nullptr) {
+      rawfile = nullptr; /* The `Zstd` #FileReader takes ownership of `rawfile`. */
+    }
+  }
+
+  /* Clean up `rawfile` if it wasn't taken over. */
+  if (rawfile != nullptr) {
+    rawfile->close(rawfile);
+  }
+  if (file == nullptr) {
+    BKE_reportf(reports->reports, RPT_WARNING, "Unrecognized file format '%s'", filepath);
+    return nullptr;
+  }
+
+  FileData *fd = filedata_new(reports);
+  fd->file = file;
+
+  return fd;
+}
+
+static FileData *blo_filedata_from_file_open(const char *filepath, BlendFileReadReport *reports)
+{
+  errno = 0;
+  const int file = BLI_open(filepath, O_BINARY | O_RDONLY, 0);
+  if (file == -1) {
+    BKE_reportf(reports->reports,
+                RPT_WARNING,
+                "Unable to open '%s': %s",
+                filepath,
+                errno ? strerror(errno) : TIP_("unknown error reading file"));
+    return nullptr;
+  }
+  return blo_filedata_from_file_descriptor(filepath, reports, file);
+}
+
+FileData *blo_filedata_from_file(const char *filepath, BlendFileReadReport *reports)
+{
+  FileData *fd = blo_filedata_from_file_open(filepath, reports);
+  if (fd != nullptr) {
+    /* needed for library_append and read_libraries */
+    BLI_strncpy(fd->relabase, filepath, sizeof(fd->relabase));
+
+    return blo_decode_and_check(fd, reports->reports);
+  }
+  return nullptr;
+}
+
+/**
+ * Same as blo_filedata_from_file(), but does not reads DNA data, only header.
+ * Use it for light access (e.g. thumbnail reading).
+ */
+static FileData *blo_filedata_from_file_minimal(const char *filepath)
+{
+  BlendFileReadReport read_report{};
+  FileData *fd = blo_filedata_from_file_open(filepath, &read_report);
+  if (fd != nullptr) {
+    decode_blender_header(fd);
+    if (fd->flags & FD_FLAGS_FILE_OK) {
+      return fd;
+    }
+    blo_filedata_free(fd);
+  }
+  return nullptr;
+}
+
+FileData *blo_filedata_from_memory(const void *mem, int memsize, BlendFileReadReport *reports)
+{
+  if (!mem || memsize < SIZEOFBLENDERHEADER) {
+    BKE_report(
+        reports->reports, RPT_WARNING, (mem) ? TIP_("Unable to read") : TIP_("Unable to open"));
+    return nullptr;
+  }
+
+  FileReader *mem_file = BLI_filereader_new_memory(mem, memsize);
+  FileReader *file = mem_file;
+
+  if (BLI_file_magic_is_gzip(static_cast(mem))) {
+    file = BLI_filereader_new_gzip(mem_file);
+  }
+  else if (BLI_file_magic_is_zstd(static_cast(mem))) {
+    file = BLI_filereader_new_zstd(mem_file);
+  }
+
+  if (file == nullptr) {
+    /* Compression initialization failed. */
+    mem_file->close(mem_file);
+    return nullptr;
+  }
+
+  FileData *fd = filedata_new(reports);
+  fd->file = file;
+
+  return blo_decode_and_check(fd, reports->reports);
+}
+
+FileData *blo_filedata_from_memfile(MemFile *memfile,
+                                    const struct BlendFileReadParams *params,
+                                    BlendFileReadReport *reports)
+{
+  if (!memfile) {
+    BKE_report(reports->reports, RPT_WARNING, "Unable to open blend ");
+    return nullptr;
+  }
+
+  FileData *fd = filedata_new(reports);
+  fd->file = BLO_memfile_new_filereader(memfile, params->undo_direction);
+  fd->undo_direction = params->undo_direction;
+  fd->flags |= FD_FLAGS_IS_MEMFILE;
+
+  return blo_decode_and_check(fd, reports->reports);
+}
+
+void blo_filedata_free(FileData *fd)
+{
+  if (fd) {
+
+    /* Free all BHeadN data blocks */
+#ifndef NDEBUG
+    BLI_freelistN(&fd->bhead_list);
+#else
+    /* Sanity check we're not keeping memory we don't need. */
+    LISTBASE_FOREACH_MUTABLE (BHeadN *, new_bhead, &fd->bhead_list) {
+      if (fd->file->seek != nullptr && BHEAD_USE_READ_ON_DEMAND(&new_bhead->bhead)) {
+        BLI_assert(new_bhead->has_data == 0);
+      }
+      MEM_freeN(new_bhead);
+    }
+#endif
+    fd->file->close(fd->file);
+
+    if (fd->filesdna) {
+      DNA_sdna_free(fd->filesdna);
+    }
+    if (fd->compflags) {
+      MEM_freeN((void *)fd->compflags);
+    }
+    if (fd->reconstruct_info) {
+      DNA_reconstruct_info_free(fd->reconstruct_info);
+    }
+
+    if (fd->datamap) {
+      oldnewmap_free(fd->datamap);
+    }
+    if (fd->globmap) {
+      oldnewmap_free(fd->globmap);
+    }
+    if (fd->packedmap) {
+      oldnewmap_free(fd->packedmap);
+    }
+    if (fd->libmap && !(fd->flags & FD_FLAGS_NOT_MY_LIBMAP)) {
+      oldnewmap_free(fd->libmap);
+    }
+    if (fd->old_idmap != nullptr) {
+      BKE_main_idmap_destroy(fd->old_idmap);
+    }
+    blo_cache_storage_end(fd);
+    if (fd->bheadmap) {
+      MEM_freeN(fd->bheadmap);
+    }
+
+#ifdef USE_GHASH_BHEAD
+    if (fd->bhead_idname_hash) {
+      BLI_ghash_free(fd->bhead_idname_hash, nullptr, nullptr);
+    }
+#endif
+
+    MEM_freeN(fd);
+  }
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Public Utilities
+ * \{ */
+
+bool BLO_has_bfile_extension(const char *str)
+{
+  const char *ext_test[4] = {".blend", ".ble", ".blend.gz", nullptr};
+  return BLI_path_extension_check_array(str, ext_test);
+}
+
+bool BLO_library_path_explode(const char *path, char *r_dir, char **r_group, char **r_name)
+{
+  /* We might get some data names with slashes,
+   * so we have to go up in path until we find blend file itself,
+   * then we know next path item is group, and everything else is data name. */
+  char *slash = nullptr, *prev_slash = nullptr, c = '\0';
+
+  r_dir[0] = '\0';
+  if (r_group) {
+    *r_group = nullptr;
+  }
+  if (r_name) {
+    *r_name = nullptr;
+  }
+
+  /* if path leads to an existing directory, we can be sure we're not (in) a library */
+  if (BLI_is_dir(path)) {
+    return false;
+  }
+
+  strcpy(r_dir, path);
+
+  while ((slash = (char *)BLI_path_slash_rfind(r_dir))) {
+    char tc = *slash;
+    *slash = '\0';
+    if (BLO_has_bfile_extension(r_dir) && BLI_is_file(r_dir)) {
+      break;
+    }
+    if (STREQ(r_dir, BLO_EMBEDDED_STARTUP_BLEND)) {
+      break;
+    }
+
+    if (prev_slash) {
+      *prev_slash = c;
+    }
+    prev_slash = slash;
+    c = tc;
+  }
+
+  if (!slash) {
+    return false;
+  }
+
+  if (slash[1] != '\0') {
+    BLI_assert(strlen(slash + 1) < BLO_GROUP_MAX);
+    if (r_group) {
+      *r_group = slash + 1;
+    }
+  }
+
+  if (prev_slash && (prev_slash[1] != '\0')) {
+    BLI_assert(strlen(prev_slash + 1) < MAX_ID_NAME - 2);
+    if (r_name) {
+      *r_name = prev_slash + 1;
+    }
+  }
+
+  return true;
+}
+
+BlendThumbnail *BLO_thumbnail_from_file(const char *filepath)
+{
+  FileData *fd;
+  BlendThumbnail *data = nullptr;
+  int *fd_data;
+
+  fd = blo_filedata_from_file_minimal(filepath);
+  fd_data = fd ? read_file_thumbnail(fd) : nullptr;
+
+  if (fd_data) {
+    const int width = fd_data[0];
+    const int height = fd_data[1];
+    if (BLEN_THUMB_MEMSIZE_IS_VALID(width, height)) {
+      const size_t data_size = BLEN_THUMB_MEMSIZE(width, height);
+      data = static_cast(MEM_mallocN(data_size, __func__));
+      if (data) {
+        BLI_assert((data_size - sizeof(*data)) ==
+                   (BLEN_THUMB_MEMSIZE_FILE(width, height) - (sizeof(*fd_data) * 2)));
+        data->width = width;
+        data->height = height;
+        memcpy(data->rect, &fd_data[2], data_size - sizeof(*data));
+      }
+    }
+  }
+
+  blo_filedata_free(fd);
+
+  return data;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Old/New Pointer Map
+ * \{ */
+
+/* Only direct data-blocks. */
+static void *newdataadr(FileData *fd, const void *adr)
+{
+  return oldnewmap_lookup_and_inc(fd->datamap, adr, true);
+}
+
+/* Only direct data-blocks. */
+static void *newdataadr_no_us(FileData *fd, const void *adr)
+{
+  return oldnewmap_lookup_and_inc(fd->datamap, adr, false);
+}
+
+void *blo_read_get_new_globaldata_address(FileData *fd, const void *adr)
+{
+  return oldnewmap_lookup_and_inc(fd->globmap, adr, true);
+}
+
+/* Used to restore packed data after undo. */
+static void *newpackedadr(FileData *fd, const void *adr)
+{
+  if (fd->packedmap && adr) {
+    return oldnewmap_lookup_and_inc(fd->packedmap, adr, true);
+  }
+
+  return oldnewmap_lookup_and_inc(fd->datamap, adr, true);
+}
+
+/* only lib data */
+static void *newlibadr(FileData *fd, const void *lib, const void *adr)
+{
+  return oldnewmap_liblookup(fd->libmap, adr, lib);
+}
+
+void *blo_do_versions_newlibadr(FileData *fd, const void *lib, const void *adr)
+{
+  return newlibadr(fd, lib, adr);
+}
+
+/* increases user number */
+static void change_link_placeholder_to_real_ID_pointer_fd(FileData *fd,
+                                                          const void *old,
+                                                          void *newp)
+{
+  for (int i = 0; i < fd->libmap->nentries; i++) {
+    OldNew *entry = &fd->libmap->entries[i];
+
+    if (old == entry->newp && entry->nr == ID_LINK_PLACEHOLDER) {
+      entry->newp = newp;
+      if (newp) {
+        entry->nr = GS(((ID *)newp)->name);
+      }
+    }
+  }
+}
+
+static void change_link_placeholder_to_real_ID_pointer(ListBase *mainlist,
+                                                       FileData *basefd,
+                                                       void *old,
+                                                       void *newp)
+{
+  LISTBASE_FOREACH (Main *, mainptr, mainlist) {
+    FileData *fd;
+
+    if (mainptr->curlib) {
+      fd = mainptr->curlib->filedata;
+    }
+    else {
+      fd = basefd;
+    }
+
+    if (fd) {
+      change_link_placeholder_to_real_ID_pointer_fd(fd, old, newp);
+    }
+  }
+}
+
+/* XXX disabled this feature - packed files also belong in temp saves and quit.blend,
+ * to make restore work. */
+
+static void insert_packedmap(FileData *fd, PackedFile *pf)
+{
+  oldnewmap_insert(fd->packedmap, pf, pf, 0);
+  oldnewmap_insert(fd->packedmap, pf->data, pf->data, 0);
+}
+
+void blo_make_packed_pointer_map(FileData *fd, Main *oldmain)
+{
+  fd->packedmap = oldnewmap_new();
+
+  LISTBASE_FOREACH (Image *, ima, &oldmain->images) {
+    if (ima->packedfile) {
+      insert_packedmap(fd, ima->packedfile);
+    }
+
+    LISTBASE_FOREACH (ImagePackedFile *, imapf, &ima->packedfiles) {
+      if (imapf->packedfile) {
+        insert_packedmap(fd, imapf->packedfile);
+      }
+    }
+  }
+
+  LISTBASE_FOREACH (VFont *, vfont, &oldmain->fonts) {
+    if (vfont->packedfile) {
+      insert_packedmap(fd, vfont->packedfile);
+    }
+  }
+
+  LISTBASE_FOREACH (bSound *, sound, &oldmain->sounds) {
+    if (sound->packedfile) {
+      insert_packedmap(fd, sound->packedfile);
+    }
+  }
+
+  LISTBASE_FOREACH (Volume *, volume, &oldmain->volumes) {
+    if (volume->packedfile) {
+      insert_packedmap(fd, volume->packedfile);
+    }
+  }
+
+  LISTBASE_FOREACH (Library *, lib, &oldmain->libraries) {
+    if (lib->packedfile) {
+      insert_packedmap(fd, lib->packedfile);
+    }
+  }
+}
+
+void blo_end_packed_pointer_map(FileData *fd, Main *oldmain)
+{
+  OldNew *entry = fd->packedmap->entries;
+
+  /* used entries were restored, so we put them to zero */
+  for (int i = 0; i < fd->packedmap->nentries; i++, entry++) {
+    if (entry->nr > 0) {
+      entry->newp = nullptr;
+    }
+  }
+
+  LISTBASE_FOREACH (Image *, ima, &oldmain->images) {
+    ima->packedfile = static_cast(newpackedadr(fd, ima->packedfile));
+
+    LISTBASE_FOREACH (ImagePackedFile *, imapf, &ima->packedfiles) {
+      imapf->packedfile = static_cast(newpackedadr(fd, imapf->packedfile));
+    }
+  }
+
+  LISTBASE_FOREACH (VFont *, vfont, &oldmain->fonts) {
+    vfont->packedfile = static_cast(newpackedadr(fd, vfont->packedfile));
+  }
+
+  LISTBASE_FOREACH (bSound *, sound, &oldmain->sounds) {
+    sound->packedfile = static_cast(newpackedadr(fd, sound->packedfile));
+  }
+
+  LISTBASE_FOREACH (Library *, lib, &oldmain->libraries) {
+    lib->packedfile = static_cast(newpackedadr(fd, lib->packedfile));
+  }
+
+  LISTBASE_FOREACH (Volume *, volume, &oldmain->volumes) {
+    volume->packedfile = static_cast(newpackedadr(fd, volume->packedfile));
+  }
+}
+
+void blo_add_library_pointer_map(ListBase *old_mainlist, FileData *fd)
+{
+  ListBase *lbarray[INDEX_ID_MAX];
+
+  LISTBASE_FOREACH (Main *, ptr, old_mainlist) {
+    int i = set_listbasepointers(ptr, lbarray);
+    while (i--) {
+      LISTBASE_FOREACH (ID *, id, lbarray[i]) {
+        oldnewmap_lib_insert(fd, id, id, GS(id->name));
+      }
+    }
+  }
+
+  fd->old_mainlist = old_mainlist;
+}
+
+void blo_make_old_idmap_from_main(FileData *fd, Main *bmain)
+{
+  if (fd->old_idmap != nullptr) {
+    BKE_main_idmap_destroy(fd->old_idmap);
+  }
+  fd->old_idmap = BKE_main_idmap_create(bmain, false, nullptr, MAIN_IDMAP_TYPE_UUID);
+}
+
+typedef struct BLOCacheStorage {
+  GHash *cache_map;
+  MemArena *memarena;
+} BLOCacheStorage;
+
+typedef struct BLOCacheStorageValue {
+  void *cache_v;
+  uint new_usage_count;
+} BLOCacheStorageValue;
+
+/** Register a cache data entry to be preserved when reading some undo memfile. */
+static void blo_cache_storage_entry_register(
+    ID *id, const IDCacheKey *key, void **cache_p, uint UNUSED(flags), void *cache_storage_v)
+{
+  BLI_assert(key->id_session_uuid == id->session_uuid);
+  UNUSED_VARS_NDEBUG(id);
+
+  BLOCacheStorage *cache_storage = static_cast(cache_storage_v);
+  BLI_assert(!BLI_ghash_haskey(cache_storage->cache_map, key));
+
+  IDCacheKey *storage_key = static_cast(
+      BLI_memarena_alloc(cache_storage->memarena, sizeof(*storage_key)));
+  *storage_key = *key;
+  BLOCacheStorageValue *storage_value = static_cast(
+      BLI_memarena_alloc(cache_storage->memarena, sizeof(*storage_value)));
+  storage_value->cache_v = *cache_p;
+  storage_value->new_usage_count = 0;
+  BLI_ghash_insert(cache_storage->cache_map, storage_key, storage_value);
+}
+
+/** Restore a cache data entry from old ID into new one, when reading some undo memfile. */
+static void blo_cache_storage_entry_restore_in_new(
+    ID *UNUSED(id), const IDCacheKey *key, void **cache_p, uint flags, void *cache_storage_v)
+{
+  BLOCacheStorage *cache_storage = static_cast(cache_storage_v);
+
+  if (cache_storage == nullptr) {
+    /* In non-undo case, only clear the pointer if it is a purely runtime one.
+     * If it may be stored in a persistent way in the .blend file, direct_link code is responsible
+     * to properly deal with it. */
+    if ((flags & IDTYPE_CACHE_CB_FLAGS_PERSISTENT) == 0) {
+      *cache_p = nullptr;
+    }
+    return;
+  }
+
+  BLOCacheStorageValue *storage_value = static_cast(
+      BLI_ghash_lookup(cache_storage->cache_map, key));
+  if (storage_value == nullptr) {
+    *cache_p = nullptr;
+    return;
+  }
+  storage_value->new_usage_count++;
+  *cache_p = storage_value->cache_v;
+}
+
+/** Clear as needed a cache data entry from old ID, when reading some undo memfile. */
+static void blo_cache_storage_entry_clear_in_old(ID *UNUSED(id),
+                                                 const IDCacheKey *key,
+                                                 void **cache_p,
+                                                 uint UNUSED(flags),
+                                                 void *cache_storage_v)
+{
+  BLOCacheStorage *cache_storage = static_cast(cache_storage_v);
+
+  BLOCacheStorageValue *storage_value = static_cast(
+      BLI_ghash_lookup(cache_storage->cache_map, key));
+  if (storage_value == nullptr) {
+    *cache_p = nullptr;
+    return;
+  }
+  /* If that cache has been restored into some new ID, we want to remove it from old one, otherwise
+   * keep it there so that it gets properly freed together with its ID. */
+  if (storage_value->new_usage_count != 0) {
+    *cache_p = nullptr;
+  }
+  else {
+    BLI_assert(*cache_p == storage_value->cache_v);
+  }
+}
+
+void blo_cache_storage_init(FileData *fd, Main *bmain)
+{
+  if (fd->flags & FD_FLAGS_IS_MEMFILE) {
+    BLI_assert(fd->cache_storage == nullptr);
+    fd->cache_storage = static_cast(
+        MEM_mallocN(sizeof(*fd->cache_storage), __func__));
+    fd->cache_storage->memarena = BLI_memarena_new(BLI_MEMARENA_STD_BUFSIZE, __func__);
+    fd->cache_storage->cache_map = BLI_ghash_new(
+        BKE_idtype_cache_key_hash, BKE_idtype_cache_key_cmp, __func__);
+
+    ListBase *lb;
+    FOREACH_MAIN_LISTBASE_BEGIN (bmain, lb) {
+      ID *id = static_cast(lb->first);
+      if (id == nullptr) {
+        continue;
+      }
+
+      const IDTypeInfo *type_info = BKE_idtype_get_info_from_id(id);
+      if (type_info->foreach_cache == nullptr) {
+        continue;
+      }
+
+      FOREACH_MAIN_LISTBASE_ID_BEGIN (lb, id) {
+        if (ID_IS_LINKED(id)) {
+          continue;
+        }
+        BKE_idtype_id_foreach_cache(id, blo_cache_storage_entry_register, fd->cache_storage);
+      }
+      FOREACH_MAIN_LISTBASE_ID_END;
+    }
+    FOREACH_MAIN_LISTBASE_END;
+  }
+  else {
+    fd->cache_storage = nullptr;
+  }
+}
+
+void blo_cache_storage_old_bmain_clear(FileData *fd, Main *bmain_old)
+{
+  if (fd->cache_storage != nullptr) {
+    ListBase *lb;
+    FOREACH_MAIN_LISTBASE_BEGIN (bmain_old, lb) {
+      ID *id = static_cast(lb->first);
+      if (id == nullptr) {
+        continue;
+      }
+
+      const IDTypeInfo *type_info = BKE_idtype_get_info_from_id(id);
+      if (type_info->foreach_cache == nullptr) {
+        continue;
+      }
+
+      FOREACH_MAIN_LISTBASE_ID_BEGIN (lb, id) {
+        if (ID_IS_LINKED(id)) {
+          continue;
+        }
+        BKE_idtype_id_foreach_cache(id, blo_cache_storage_entry_clear_in_old, fd->cache_storage);
+      }
+      FOREACH_MAIN_LISTBASE_ID_END;
+    }
+    FOREACH_MAIN_LISTBASE_END;
+  }
+}
+
+void blo_cache_storage_end(FileData *fd)
+{
+  if (fd->cache_storage != nullptr) {
+    BLI_ghash_free(fd->cache_storage->cache_map, nullptr, nullptr);
+    BLI_memarena_free(fd->cache_storage->memarena);
+    MEM_freeN(fd->cache_storage);
+    fd->cache_storage = nullptr;
+  }
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name DNA Struct Loading
+ * \{ */
+
+static void switch_endian_structs(const struct SDNA *filesdna, BHead *bhead)
+{
+  int blocksize, nblocks;
+  char *data;
+
+  data = (char *)(bhead + 1);
+  blocksize = filesdna->types_size[filesdna->structs[bhead->SDNAnr]->type];
+
+  nblocks = bhead->nr;
+  while (nblocks--) {
+    DNA_struct_switch_endian(filesdna, bhead->SDNAnr, data);
+
+    data += blocksize;
+  }
+}
+
+static void *read_struct(FileData *fd, BHead *bh, const char *blockname)
+{
+  void *temp = nullptr;
+
+  if (bh->len) {
+#ifdef USE_BHEAD_READ_ON_DEMAND
+    BHead *bh_orig = bh;
+#endif
+
+    /* switch is based on file dna */
+    if (bh->SDNAnr && (fd->flags & FD_FLAGS_SWITCH_ENDIAN)) {
+#ifdef USE_BHEAD_READ_ON_DEMAND
+      if (BHEADN_FROM_BHEAD(bh)->has_data == false) {
+        bh = blo_bhead_read_full(fd, bh);
+        if (UNLIKELY(bh == nullptr)) {
+          fd->flags &= ~FD_FLAGS_FILE_OK;
+          return nullptr;
+        }
+      }
+#endif
+      switch_endian_structs(fd->filesdna, bh);
+    }
+
+    if (fd->compflags[bh->SDNAnr] != SDNA_CMP_REMOVED) {
+      if (fd->compflags[bh->SDNAnr] == SDNA_CMP_NOT_EQUAL) {
+#ifdef USE_BHEAD_READ_ON_DEMAND
+        if (BHEADN_FROM_BHEAD(bh)->has_data == false) {
+          bh = blo_bhead_read_full(fd, bh);
+          if (UNLIKELY(bh == nullptr)) {
+            fd->flags &= ~FD_FLAGS_FILE_OK;
+            return nullptr;
+          }
+        }
+#endif
+        temp = DNA_struct_reconstruct(fd->reconstruct_info, bh->SDNAnr, bh->nr, (bh + 1));
+      }
+      else {
+        /* SDNA_CMP_EQUAL */
+        temp = MEM_mallocN(bh->len, blockname);
+#ifdef USE_BHEAD_READ_ON_DEMAND
+        if (BHEADN_FROM_BHEAD(bh)->has_data) {
+          memcpy(temp, (bh + 1), bh->len);
+        }
+        else {
+          /* Instead of allocating the bhead, then copying it,
+           * read the data from the file directly into the memory. */
+          if (UNLIKELY(!blo_bhead_read_data(fd, bh, temp))) {
+            fd->flags &= ~FD_FLAGS_FILE_OK;
+            MEM_freeN(temp);
+            temp = nullptr;
+          }
+        }
+#else
+        memcpy(temp, (bh + 1), bh->len);
+#endif
+      }
+    }
+
+#ifdef USE_BHEAD_READ_ON_DEMAND
+    if (bh_orig != bh) {
+      MEM_freeN(BHEADN_FROM_BHEAD(bh));
+    }
+#endif
+  }
+
+  return temp;
+}
+
+/* Like read_struct, but gets a pointer without allocating. Only works for
+ * undo since DNA must match. */
+static const void *peek_struct_undo(FileData *fd, BHead *bhead)
+{
+  BLI_assert(fd->flags & FD_FLAGS_IS_MEMFILE);
+  UNUSED_VARS_NDEBUG(fd);
+  return (bhead->len) ? (const void *)(bhead + 1) : nullptr;
+}
+
+static void link_glob_list(FileData *fd, ListBase *lb) /* for glob data */
+{
+  Link *ln, *prev;
+  void *poin;
+
+  if (BLI_listbase_is_empty(lb)) {
+    return;
+  }
+  poin = newdataadr(fd, lb->first);
+  if (lb->first) {
+    oldnewmap_insert(fd->globmap, lb->first, poin, 0);
+  }
+  lb->first = poin;
+
+  ln = static_cast(lb->first);
+  prev = nullptr;
+  while (ln) {
+    poin = newdataadr(fd, ln->next);
+    if (ln->next) {
+      oldnewmap_insert(fd->globmap, ln->next, poin, 0);
+    }
+    ln->next = static_cast(poin);
+    ln->prev = prev;
+    prev = ln;
+    ln = ln->next;
+  }
+  lb->last = prev;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Read ID
+ * \{ */
+
+static void lib_link_id(BlendLibReader *reader, ID *id);
+
+static void lib_link_id_embedded_id(BlendLibReader *reader, ID *id)
+{
+
+  /* Handle 'private IDs'. */
+  bNodeTree *nodetree = ntreeFromID(id);
+  if (nodetree != nullptr) {
+    lib_link_id(reader, &nodetree->id);
+    ntreeBlendReadLib(reader, nodetree);
+  }
+
+  if (GS(id->name) == ID_SCE) {
+    Scene *scene = (Scene *)id;
+    if (scene->master_collection != nullptr) {
+      lib_link_id(reader, &scene->master_collection->id);
+      BKE_collection_blend_read_lib(reader, scene->master_collection);
+    }
+  }
+}
+
+static void lib_link_id(BlendLibReader *reader, ID *id)
+{
+  /* NOTE: WM IDProperties are never written to file, hence they should always be nullptr here. */
+  BLI_assert((GS(id->name) != ID_WM) || id->properties == nullptr);
+  IDP_BlendReadLib(reader, id->lib, id->properties);
+
+  AnimData *adt = BKE_animdata_from_id(id);
+  if (adt != nullptr) {
+    BKE_animdata_blend_read_lib(reader, id, adt);
+  }
+
+  if (id->override_library) {
+    BLO_read_id_address(reader, id->lib, &id->override_library->reference);
+    BLO_read_id_address(reader, id->lib, &id->override_library->storage);
+    BLO_read_id_address(reader, id->lib, &id->override_library->hierarchy_root);
+  }
+
+  lib_link_id_embedded_id(reader, id);
+}
+
+static void direct_link_id_override_property_operation_cb(BlendDataReader *reader, void *data)
+{
+  IDOverrideLibraryPropertyOperation *opop = static_cast(
+      data);
+
+  BLO_read_data_address(reader, &opop->subitem_reference_name);
+  BLO_read_data_address(reader, &opop->subitem_local_name);
+
+  opop->tag = 0; /* Runtime only. */
+}
+
+static void direct_link_id_override_property_cb(BlendDataReader *reader, void *data)
+{
+  IDOverrideLibraryProperty *op = static_cast(data);
+
+  BLO_read_data_address(reader, &op->rna_path);
+
+  op->tag = 0; /* Runtime only. */
+
+  BLO_read_list_cb(reader, &op->operations, direct_link_id_override_property_operation_cb);
+}
+
+static void direct_link_id_common(
+    BlendDataReader *reader, Library *current_library, ID *id, ID *id_old, const int tag);
+
+static void direct_link_id_embedded_id(BlendDataReader *reader,
+                                       Library *current_library,
+                                       ID *id,
+                                       ID *id_old)
+{
+  /* Handle 'private IDs'. */
+  bNodeTree **nodetree = BKE_ntree_ptr_from_id(id);
+  if (nodetree != nullptr && *nodetree != nullptr) {
+    BLO_read_data_address(reader, nodetree);
+    direct_link_id_common(reader,
+                          current_library,
+                          (ID *)*nodetree,
+                          id_old != nullptr ? (ID *)ntreeFromID(id_old) : nullptr,
+                          0);
+    ntreeBlendReadData(reader, id, *nodetree);
+  }
+
+  if (GS(id->name) == ID_SCE) {
+    Scene *scene = (Scene *)id;
+    if (scene->master_collection != nullptr) {
+      BLO_read_data_address(reader, &scene->master_collection);
+      direct_link_id_common(reader,
+                            current_library,
+                            &scene->master_collection->id,
+                            id_old != nullptr ? &((Scene *)id_old)->master_collection->id :
+                                                nullptr,
+                            0);
+      BKE_collection_blend_read_data(reader, scene->master_collection, &scene->id);
+    }
+  }
+}
+
+static int direct_link_id_restore_recalc_exceptions(const ID *id_current)
+{
+  /* Exception for armature objects, where the pose has direct points to the
+   * armature data-block. */
+  if (GS(id_current->name) == ID_OB && ((Object *)id_current)->pose) {
+    return ID_RECALC_GEOMETRY;
+  }
+
+  return 0;
+}
+
+static int direct_link_id_restore_recalc(const FileData *fd,
+                                         const ID *id_target,
+                                         const ID *id_current,
+                                         const bool is_identical)
+{
+  /* These are the evaluations that had not been performed yet at the time the
+   * target undo state was written. These need to be done again, since they may
+   * flush back changes to the original datablock. */
+  int recalc = id_target->recalc;
+
+  if (id_current == nullptr) {
+    /* ID does not currently exist in the database, so also will not exist in
+     * the dependency graphs. That means it will be newly created and as a
+     * result also fully re-evaluated regardless of the recalc flag set here. */
+    recalc |= ID_RECALC_ALL;
+  }
+  else {
+    /* If the contents datablock changed, the depsgraph needs to copy the
+     * datablock again to ensure it matches the original datablock. */
+    if (!is_identical) {
+      recalc |= ID_RECALC_COPY_ON_WRITE;
+    }
+
+    /* Special exceptions. */
+    recalc |= direct_link_id_restore_recalc_exceptions(id_current);
+
+    /* Evaluations for the current state that have not been performed yet
+     * by the time we are performing this undo step. */
+    recalc |= id_current->recalc;
+
+    /* Tags that were set between the target state and the current state,
+     * that we need to perform again. */
+    if (fd->undo_direction == STEP_UNDO) {
+      /* Undo: tags from target to the current state. */
+      recalc |= id_current->recalc_up_to_undo_push;
+    }
+    else {
+      BLI_assert(fd->undo_direction == STEP_REDO);
+      /* Redo: tags from current to the target state. */
+      recalc |= id_target->recalc_up_to_undo_push;
+    }
+  }
+
+  return recalc;
+}
+
+static void direct_link_id_common(
+    BlendDataReader *reader, Library *current_library, ID *id, ID *id_old, const int tag)
+{
+  if (!BLO_read_data_is_undo(reader)) {
+    /* When actually reading a file, we do want to reset/re-generate session uuids.
+     * In undo case, we want to re-use existing ones. */
+    id->session_uuid = MAIN_ID_SESSION_UUID_UNSET;
+  }
+
+  if ((tag & LIB_TAG_TEMP_MAIN) == 0) {
+    BKE_lib_libblock_session_uuid_ensure(id);
+  }
+
+  id->lib = current_library;
+  id->us = ID_FAKE_USERS(id);
+  id->icon_id = 0;
+  id->newid = nullptr; /* Needed because .blend may have been saved with crap value here... */
+  id->orig_id = nullptr;
+  id->py_instance = nullptr;
+
+  /* Initialize with provided tag. */
+  id->tag = tag;
+
+  if (ID_IS_LINKED(id)) {
+    id->library_weak_reference = nullptr;
+  }
+  else {
+    BLO_read_data_address(reader, &id->library_weak_reference);
+  }
+
+  if (tag & LIB_TAG_ID_LINK_PLACEHOLDER) {
+    /* For placeholder we only need to set the tag and properly initialize generic ID fields above,
+     * no further data to read. */
+    return;
+  }
+
+  if (id->asset_data) {
+    BLO_read_data_address(reader, &id->asset_data);
+    BKE_asset_metadata_read(reader, id->asset_data);
+    /* Restore runtime asset type info. */
+    const IDTypeInfo *id_type = BKE_idtype_get_info_from_id(id);
+    id->asset_data->local_type_info = id_type->asset_type_info;
+  }
+
+  /* Link direct data of ID properties. */
+  if (id->properties) {
+    BLO_read_data_address(reader, &id->properties);
+    /* this case means the data was written incorrectly, it should not happen */
+    IDP_BlendDataRead(reader, &id->properties);
+  }
+
+  id->flag &= ~LIB_INDIRECT_WEAK_LINK;
+
+  /* NOTE: It is important to not clear the recalc flags for undo/redo.
+   * Preserving recalc flags on redo/undo is the only way to make dependency graph detect
+   * that animation is to be evaluated on undo/redo. If this is not enforced by the recalc
+   * flags dependency graph does not do animation update to avoid loss of unkeyed changes.,
+   * which conflicts with undo/redo of changes to animation data itself.
+   *
+   * But for regular file load we clear the flag, since the flags might have been changed since
+   * the version the file has been saved with. */
+  if (!BLO_read_data_is_undo(reader)) {
+    id->recalc = 0;
+    id->recalc_after_undo_push = 0;
+  }
+  else if ((reader->fd->skip_flags & BLO_READ_SKIP_UNDO_OLD_MAIN) == 0) {
+    id->recalc = direct_link_id_restore_recalc(reader->fd, id, id_old, false);
+    id->recalc_after_undo_push = 0;
+  }
+
+  /* Link direct data of overrides. */
+  if (id->override_library) {
+    BLO_read_data_address(reader, &id->override_library);
+    /* Work around file corruption on writing, see T86853. */
+    if (id->override_library != nullptr) {
+      BLO_read_list_cb(
+          reader, &id->override_library->properties, direct_link_id_override_property_cb);
+      id->override_library->runtime = nullptr;
+    }
+  }
+
+  DrawDataList *drawdata = DRW_drawdatalist_from_id(id);
+  if (drawdata) {
+    BLI_listbase_clear((ListBase *)drawdata);
+  }
+
+  /* Handle 'private IDs'. */
+  direct_link_id_embedded_id(reader, current_library, id, id_old);
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Read Animation (legacy for version patching)
+ * \{ */
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Read ID: Shape Keys
+ * \{ */
+
+void blo_do_versions_key_uidgen(Key *key)
+{
+  key->uidgen = 1;
+  LISTBASE_FOREACH (KeyBlock *, block, &key->block) {
+    block->uid = key->uidgen++;
+  }
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Read ID: Scene
+ * \{ */
+
+#ifdef USE_SETSCENE_CHECK
+/**
+ * A version of #BKE_scene_validate_setscene with special checks for linked libs.
+ */
+static bool scene_validate_setscene__liblink(Scene *sce, const int totscene)
+{
+  Scene *sce_iter;
+  int a;
+
+  if (sce->set == nullptr) {
+    return true;
+  }
+
+  for (a = 0, sce_iter = sce; sce_iter->set; sce_iter = sce_iter->set, a++) {
+    /* This runs per library (before each libraries #Main has been joined),
+     * so we can't step into other libraries since `totscene` is only for this library.
+     *
+     * Also, other libraries may not have been linked yet,
+     * while we could check #LIB_TAG_NEED_LINK the library pointer check is sufficient. */
+    if (sce->id.lib != sce_iter->id.lib) {
+      return true;
+    }
+    if (sce_iter->flag & SCE_READFILE_LIBLINK_NEED_SETSCENE_CHECK) {
+      return true;
+    }
+
+    if (a > totscene) {
+      sce->set = nullptr;
+      return false;
+    }
+  }
+
+  return true;
+}
+#endif
+
+static void lib_link_scenes_check_set(Main *bmain)
+{
+#ifdef USE_SETSCENE_CHECK
+  const int totscene = BLI_listbase_count(&bmain->scenes);
+  LISTBASE_FOREACH (Scene *, sce, &bmain->scenes) {
+    if (sce->flag & SCE_READFILE_LIBLINK_NEED_SETSCENE_CHECK) {
+      sce->flag &= ~SCE_READFILE_LIBLINK_NEED_SETSCENE_CHECK;
+      if (!scene_validate_setscene__liblink(sce, totscene)) {
+        CLOG_WARN(&LOG, "Found cyclic background scene when linking %s", sce->id.name + 2);
+      }
+    }
+  }
+#else
+  UNUSED_VARS(bmain, totscene);
+#endif
+}
+
+#undef USE_SETSCENE_CHECK
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Read ID: Screen
+ * \{ */
+
+/* how to handle user count on pointer restore */
+typedef enum ePointerUserMode {
+  USER_IGNORE = 0, /* ignore user count */
+  USER_REAL = 1,   /* ensure at least one real user (fake user ignored) */
+} ePointerUserMode;
+
+static void restore_pointer_user(ID *id, ID *newid, ePointerUserMode user)
+{
+  BLI_assert(STREQ(newid->name + 2, id->name + 2));
+  BLI_assert(newid->lib == id->lib);
+  UNUSED_VARS_NDEBUG(id);
+
+  if (user == USER_REAL) {
+    id_us_ensure_real(newid);
+  }
+}
+
+#ifndef USE_GHASH_RESTORE_POINTER
+/**
+ * A version of #restore_pointer_by_name that performs a full search (slow!).
+ * Use only for limited lookups, when the overhead of
+ * creating a #IDNameLib_Map for a single lookup isn't worthwhile.
+ */
+static void *restore_pointer_by_name_main(Main *mainp, ID *id, ePointerUserMode user)
+{
+  if (id) {
+    ListBase *lb = which_libbase(mainp, GS(id->name));
+    if (lb) { /* there's still risk of checking corrupt mem (freed Ids in oops) */
+      ID *idn = lb->first;
+      for (; idn; idn = idn->next) {
+        if (STREQ(idn->name + 2, id->name + 2)) {
+          if (idn->lib == id->lib) {
+            restore_pointer_user(id, idn, user);
+            break;
+          }
+        }
+      }
+      return idn;
+    }
+  }
+  return nullptr;
+}
+#endif
+
+/**
+ * Only for undo files, or to restore a screen after reading without UI...
+ *
+ * \param user:
+ * - USER_IGNORE: no user-count change.
+ * - USER_REAL: ensure a real user (even if a fake one is set).
+ * \param id_map: lookup table, use when performing many lookups.
+ * this could be made an optional argument (falling back to a full lookup),
+ * however at the moment it's always available.
+ */
+static void *restore_pointer_by_name(struct IDNameLib_Map *id_map, ID *id, ePointerUserMode user)
+{
+#ifdef USE_GHASH_RESTORE_POINTER
+  if (id) {
+    /* use fast lookup when available */
+    ID *idn = BKE_main_idmap_lookup_id(id_map, id);
+    if (idn) {
+      restore_pointer_user(id, idn, user);
+    }
+    return idn;
+  }
+  return nullptr;
+#else
+  Main *mainp = BKE_main_idmap_main_get(id_map);
+  return restore_pointer_by_name_main(mainp, id, user);
+#endif
+}
+
+static void lib_link_seq_clipboard_pt_restore(ID *id, struct IDNameLib_Map *id_map)
+{
+  if (id) {
+    /* clipboard must ensure this */
+    BLI_assert(id->newid != nullptr);
+    id->newid = static_cast(restore_pointer_by_name(id_map, id->newid, USER_REAL));
+  }
+}
+static bool lib_link_seq_clipboard_cb(Sequence *seq, void *arg_pt)
+{
+  struct IDNameLib_Map *id_map = static_cast(arg_pt);
+
+  lib_link_seq_clipboard_pt_restore((ID *)seq->scene, id_map);
+  lib_link_seq_clipboard_pt_restore((ID *)seq->scene_camera, id_map);
+  lib_link_seq_clipboard_pt_restore((ID *)seq->clip, id_map);
+  lib_link_seq_clipboard_pt_restore((ID *)seq->mask, id_map);
+  lib_link_seq_clipboard_pt_restore((ID *)seq->sound, id_map);
+  return true;
+}
+
+static void lib_link_clipboard_restore(struct IDNameLib_Map *id_map)
+{
+  /* update IDs stored in sequencer clipboard */
+  SEQ_for_each_callback(&seqbase_clipboard, lib_link_seq_clipboard_cb, id_map);
+}
+
+static int lib_link_main_data_restore_cb(LibraryIDLinkCallbackData *cb_data)
+{
+  const int cb_flag = cb_data->cb_flag;
+  ID **id_pointer = cb_data->id_pointer;
+  if (cb_flag & IDWALK_CB_EMBEDDED || *id_pointer == nullptr) {
+    return IDWALK_RET_NOP;
+  }
+
+  /* Special ugly case here, thanks again for those non-IDs IDs... */
+  /* We probably need to add more cases here (hint: nodetrees),
+   * but will wait for changes from D5559 to get in first. */
+  if (GS((*id_pointer)->name) == ID_GR) {
+    Collection *collection = (Collection *)*id_pointer;
+    if (collection->flag & COLLECTION_IS_MASTER) {
+      /* We should never reach that point anymore, since master collection private ID should be
+       * properly tagged with IDWALK_CB_EMBEDDED. */
+      BLI_assert_unreachable();
+      return IDWALK_RET_NOP;
+    }
+  }
+
+  struct IDNameLib_Map *id_map = static_cast(cb_data->user_data);
+
+  /* NOTE: Handling of user-count here is really bad, defining its own system...
+   * Will have to be refactored at some point, but that is not top priority task for now.
+   * And all user-counts are properly recomputed at the end of the undo management code anyway. */
+  *id_pointer = static_cast(restore_pointer_by_name(
+      id_map, *id_pointer, (cb_flag & IDWALK_CB_USER_ONE) ? USER_REAL : USER_IGNORE));
+
+  return IDWALK_RET_NOP;
+}
+
+static void lib_link_main_data_restore(struct IDNameLib_Map *id_map, Main *newmain)
+{
+  ID *id;
+  FOREACH_MAIN_ID_BEGIN (newmain, id) {
+    BKE_library_foreach_ID_link(newmain, id, lib_link_main_data_restore_cb, id_map, IDWALK_NOP);
+  }
+  FOREACH_MAIN_ID_END;
+}
+
+static void lib_link_wm_xr_data_restore(struct IDNameLib_Map *id_map, wmXrData *xr_data)
+{
+  xr_data->session_settings.base_pose_object = static_cast(restore_pointer_by_name(
+      id_map, (ID *)xr_data->session_settings.base_pose_object, USER_REAL));
+}
+
+static void lib_link_window_scene_data_restore(wmWindow *win, Scene *scene, ViewLayer *view_layer)
+{
+  bScreen *screen = BKE_workspace_active_screen_get(win->workspace_hook);
+
+  LISTBASE_FOREACH (ScrArea *, area, &screen->areabase) {
+    LISTBASE_FOREACH (SpaceLink *, sl, &area->spacedata) {
+      if (sl->spacetype == SPACE_VIEW3D) {
+        View3D *v3d = (View3D *)sl;
+
+        if (v3d->camera == nullptr || v3d->scenelock) {
+          v3d->camera = scene->camera;
+        }
+
+        if (v3d->localvd) {
+          Base *base = nullptr;
+
+          v3d->localvd->camera = scene->camera;
+
+          /* Local-view can become invalid during undo/redo steps,
+           * so we exit it when no could be found. */
+          for (base = static_cast(view_layer->object_bases.first); base;
+               base = base->next) {
+            if (base->local_view_bits & v3d->local_view_uuid) {
+              break;
+            }
+          }
+          if (base == nullptr) {
+            MEM_freeN(v3d->localvd);
+            v3d->localvd = nullptr;
+            v3d->local_view_uuid = 0;
+
+            /* Region-base storage is different depending if the space is active. */
+            ListBase *regionbase = (sl == area->spacedata.first) ? &area->regionbase :
+                                                                   &sl->regionbase;
+            LISTBASE_FOREACH (ARegion *, region, regionbase) {
+              if (region->regiontype == RGN_TYPE_WINDOW) {
+                RegionView3D *rv3d = static_cast(region->regiondata);
+                if (rv3d->localvd) {
+                  MEM_freeN(rv3d->localvd);
+                  rv3d->localvd = nullptr;
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+}
+
+static void lib_link_workspace_layout_restore(struct IDNameLib_Map *id_map,
+                                              Main *newmain,
+                                              WorkSpaceLayout *layout)
+{
+  bScreen *screen = BKE_workspace_layout_screen_get(layout);
+
+  /* avoid conflicts with 2.8x branch */
+  {
+    LISTBASE_FOREACH (ScrArea *, area, &screen->areabase) {
+      LISTBASE_FOREACH (SpaceLink *, sl, &area->spacedata) {
+        if (sl->spacetype == SPACE_VIEW3D) {
+          View3D *v3d = (View3D *)sl;
+
+          v3d->camera = static_cast(
+              restore_pointer_by_name(id_map, (ID *)v3d->camera, USER_REAL));
+          v3d->ob_center = static_cast(
+              restore_pointer_by_name(id_map, (ID *)v3d->ob_center, USER_REAL));
+        }
+        else if (sl->spacetype == SPACE_GRAPH) {
+          SpaceGraph *sipo = (SpaceGraph *)sl;
+          bDopeSheet *ads = sipo->ads;
+
+          if (ads) {
+            ads->source = static_cast(
+                restore_pointer_by_name(id_map, (ID *)ads->source, USER_REAL));
+
+            if (ads->filter_grp) {
+              ads->filter_grp = static_cast(
+                  restore_pointer_by_name(id_map, (ID *)ads->filter_grp, USER_IGNORE));
+            }
+          }
+
+          /* force recalc of list of channels (i.e. includes calculating F-Curve colors)
+           * thus preventing the "black curves" problem post-undo
+           */
+          sipo->runtime.flag |= SIPO_RUNTIME_FLAG_NEED_CHAN_SYNC_COLOR;
+        }
+        else if (sl->spacetype == SPACE_PROPERTIES) {
+          SpaceProperties *sbuts = (SpaceProperties *)sl;
+          sbuts->pinid = static_cast(
+              restore_pointer_by_name(id_map, sbuts->pinid, USER_IGNORE));
+          if (sbuts->pinid == nullptr) {
+            sbuts->flag &= ~SB_PIN_CONTEXT;
+          }
+
+          /* TODO: restore path pointers: T40046
+           * (complicated because this contains data pointers too, not just ID). */
+          MEM_SAFE_FREE(sbuts->path);
+        }
+        else if (sl->spacetype == SPACE_FILE) {
+          SpaceFile *sfile = (SpaceFile *)sl;
+          sfile->op = nullptr;
+          sfile->tags = FILE_TAG_REBUILD_MAIN_FILES;
+        }
+        else if (sl->spacetype == SPACE_ACTION) {
+          SpaceAction *saction = (SpaceAction *)sl;
+
+          saction->action = static_cast(
+              restore_pointer_by_name(id_map, (ID *)saction->action, USER_REAL));
+          saction->ads.source = static_cast(
+              restore_pointer_by_name(id_map, (ID *)saction->ads.source, USER_REAL));
+
+          if (saction->ads.filter_grp) {
+            saction->ads.filter_grp = static_cast(
+                restore_pointer_by_name(id_map, (ID *)saction->ads.filter_grp, USER_IGNORE));
+          }
+
+          /* force recalc of list of channels, potentially updating the active action
+           * while we're at it (as it can only be updated that way) T28962.
+           */
+          saction->runtime.flag |= SACTION_RUNTIME_FLAG_NEED_CHAN_SYNC;
+        }
+        else if (sl->spacetype == SPACE_IMAGE) {
+          SpaceImage *sima = (SpaceImage *)sl;
+
+          sima->image = static_cast(
+              restore_pointer_by_name(id_map, (ID *)sima->image, USER_REAL));
+
+          /* this will be freed, not worth attempting to find same scene,
+           * since it gets initialized later */
+          sima->iuser.scene = nullptr;
+
+#if 0
+          /* Those are allocated and freed by space code, no need to handle them here. */
+          MEM_SAFE_FREE(sima->scopes.waveform_1);
+          MEM_SAFE_FREE(sima->scopes.waveform_2);
+          MEM_SAFE_FREE(sima->scopes.waveform_3);
+          MEM_SAFE_FREE(sima->scopes.vecscope);
+#endif
+          sima->scopes.ok = 0;
+
+          /* NOTE: pre-2.5, this was local data not lib data, but now we need this as lib data
+           * so assume that here we're doing for undo only...
+           */
+          sima->gpd = static_cast(
+              restore_pointer_by_name(id_map, (ID *)sima->gpd, USER_REAL));
+          sima->mask_info.mask = static_cast(
+              restore_pointer_by_name(id_map, (ID *)sima->mask_info.mask, USER_REAL));
+        }
+        else if (sl->spacetype == SPACE_SEQ) {
+          SpaceSeq *sseq = (SpaceSeq *)sl;
+
+          /* NOTE: pre-2.5, this was local data not lib data, but now we need this as lib data
+           * so assume that here we're doing for undo only...
+           */
+          sseq->gpd = static_cast(
+              restore_pointer_by_name(id_map, (ID *)sseq->gpd, USER_REAL));
+        }
+        else if (sl->spacetype == SPACE_NLA) {
+          SpaceNla *snla = (SpaceNla *)sl;
+          bDopeSheet *ads = snla->ads;
+
+          if (ads) {
+            ads->source = static_cast(
+                restore_pointer_by_name(id_map, (ID *)ads->source, USER_REAL));
+
+            if (ads->filter_grp) {
+              ads->filter_grp = static_cast(
+                  restore_pointer_by_name(id_map, (ID *)ads->filter_grp, USER_IGNORE));
+            }
+          }
+        }
+        else if (sl->spacetype == SPACE_TEXT) {
+          SpaceText *st = (SpaceText *)sl;
+
+          st->text = static_cast(
+              restore_pointer_by_name(id_map, (ID *)st->text, USER_IGNORE));
+          if (st->text == nullptr) {
+            st->text = static_cast(newmain->texts.first);
+          }
+        }
+        else if (sl->spacetype == SPACE_SCRIPT) {
+          SpaceScript *scpt = (SpaceScript *)sl;
+
+          scpt->script = static_cast