Merge branch 'master' into refactor-mesh-position-generic

85 files changed, 1172 insertions, 766 deletions

diff --git a/source/blender/blenkernel/BKE_DerivedMesh.h b/source/blender/blenkernel/BKE_DerivedMesh.h
index ceadd036a2a..68ce3ca7318 100644
--- a/source/blender/blenkernel/BKE_DerivedMesh.h
+++ b/source/blender/blenkernel/BKE_DerivedMesh.h
@@ -140,14 +140,6 @@ 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 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.
  *
  * \note This function must always be thread-protected by caller.
diff --git a/source/blender/blenkernel/BKE_attribute.hh b/source/blender/blenkernel/BKE_attribute.hh
index 4aa6c133e9e..21d91af55d5 100644
--- a/source/blender/blenkernel/BKE_attribute.hh
+++ b/source/blender/blenkernel/BKE_attribute.hh
@@ -553,6 +553,11 @@ class MutableAttributeAccessor : public AttributeAccessor {
   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.
    * Make sure to call #finish after changes are done.
    */
@@ -569,6 +574,19 @@ class MutableAttributeAccessor : public AttributeAccessor {
   }
 
   /**
+   * Same as above, but returns a type that makes it easier to work with the attribute as a span.
+   */
+  template<typename T>
+  SpanAttributeWriter<T> lookup_for_write_span(const AttributeIDRef &attribute_id)
+  {
+    AttributeWriter<T> attribute = this->lookup_for_write<T>(attribute_id);
+    if (attribute) {
+      return SpanAttributeWriter<T>{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
    * this attribute or there is already an attribute with that id.
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_customdata.h b/source/blender/blenkernel/BKE_customdata.h
index 09d37682b3c..24fa5f0e87a 100644
--- a/source/blender/blenkernel/BKE_customdata.h
+++ b/source/blender/blenkernel/BKE_customdata.h
@@ -178,13 +178,11 @@ bool CustomData_merge_mesh_to_bmesh(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!
+ * 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`,
diff --git a/source/blender/blenkernel/BKE_paint.h b/source/blender/blenkernel/BKE_paint.h
index 49a303ade70..a5453b6eebd 100644
--- a/source/blender/blenkernel/BKE_paint.h
+++ b/source/blender/blenkernel/BKE_paint.h
@@ -212,9 +212,7 @@ bool BKE_paint_always_hide_test(struct Object *ob);
 /**
  * Returns non-zero if any of the face's vertices are hidden, zero otherwise.
  */
-bool paint_is_face_hidden(const struct MLoopTri *lt,
-                          const bool *hide_vert,
-                          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.
@@ -688,7 +686,7 @@ 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);
 
 /**
@@ -697,6 +695,7 @@ 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);
 int BKE_sculpt_mask_layers_ensure(struct Object *ob, struct MultiresModifierData *mmd);
 void BKE_sculpt_toolsettings_data_ensure(struct Scene *scene);
 
@@ -718,18 +717,17 @@ 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);
+ * If a face set layer exists, initialize its visiblity (sign) from the mesh's hidden values.
+ */
+void BKE_sculpt_face_sets_update_from_base_mesh_visibility(struct Mesh *mesh);
 
 /**
- * Ensures we do have expected mesh data in original mesh for the sculpt mode.
+ * Makes sculpt data consistent with other data on the mesh.
  *
  * \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_ensure_orig_mesh_data(struct Object *object);
 
 /**
  * Test if PBVH can be used directly for drawing, which is faster than
diff --git a/source/blender/blenkernel/BKE_pbvh.h b/source/blender/blenkernel/BKE_pbvh.h
index 3abc62b2070..037b02c1acb 100644
--- a/source/blender/blenkernel/BKE_pbvh.h
+++ b/source/blender/blenkernel/BKE_pbvh.h
@@ -670,6 +670,8 @@ 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);
 bool BKE_pbvh_get_color_layer(const struct Mesh *me,
diff --git a/source/blender/blenkernel/intern/DerivedMesh.cc b/source/blender/blenkernel/intern/DerivedMesh.cc
index dda9ee20e58..790f549b12d 100644
--- a/source/blender/blenkernel/intern/DerivedMesh.cc
+++ b/source/blender/blenkernel/intern/DerivedMesh.cc
@@ -148,54 +148,6 @@ 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));
@@ -234,10 +186,6 @@ 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;
 
@@ -332,36 +280,6 @@ 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;
@@ -1803,7 +1721,7 @@ 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
diff --git a/source/blender/blenkernel/intern/appdir.c b/source/blender/blenkernel/intern/appdir.c
index 24e4305d916..96ac81fdb63 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;
 #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;
diff --git a/source/blender/blenkernel/intern/attribute_access.cc b/source/blender/blenkernel/intern/attribute_access.cc
index 6ca3a286a5e..27c54a3d4a7 100644
--- a/source/blender/blenkernel/intern/attribute_access.cc
+++ b/source/blender/blenkernel/intern/attribute_access.cc
@@ -726,8 +726,22 @@ 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()
@@ -875,6 +889,16 @@ GAttributeWriter MutableAttributeAccessor::lookup_for_write(const AttributeIDRef
   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,
diff --git a/source/blender/blenkernel/intern/cdderivedmesh.c b/source/blender/blenkernel/intern/cdderivedmesh.c
index ab70596a739..e3dd26c0a20 100644
--- a/source/blender/blenkernel/intern/cdderivedmesh.c
+++ b/source/blender/blenkernel/intern/cdderivedmesh.c
@@ -244,44 +244,4 @@ 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->positions = source->dupVertArray(source);
-  cddm->medge = source->dupEdgeArray(source);
-
-  CustomData_add_layer_named(
-      &dm->vertData, CD_PROP_FLOAT3, CD_ASSIGN, cddm->positions, numVerts, "position");
-  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;
-}
+<<<<<<< HEAD
diff --git a/source/blender/blenkernel/intern/curves_geometry.cc b/source/blender/blenkernel/intern/curves_geometry.cc
index 35b209179d3..1b4508d99c1 100644
--- a/source/blender/blenkernel/intern/curves_geometry.cc
+++ b/source/blender/blenkernel/intern/curves_geometry.cc
@@ -963,11 +963,11 @@ void CurvesGeometry::ensure_can_interpolate_to_evaluated() 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));
   }
@@ -1392,57 +1392,47 @@ static bool layer_matches_name_and_type(const CustomDataLayer &layer,
 
 void CurvesGeometry::reverse_curves(const IndexMask curves_to_reverse)
 {
-  CustomData_duplicate_referenced_layers(&this->point_data, this->points_num());
+  Set<StringRef> 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<float3> positions_left;
-  MutableSpan<float3> positions_right;
-  MutableSpan<int8_t> types_left;
-  MutableSpan<int8_t> 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<float3 *>(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<float3 *>(layer.data), this->points_num()};
-      continue;
-    }
-    if (types_left.is_empty() &&
-        layer_matches_name_and_type(layer, ATTR_HANDLE_TYPE_LEFT, CD_PROP_INT8)) {
-      types_left = {static_cast<int8_t *>(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_right.is_empty() &&
-        layer_matches_name_and_type(layer, ATTR_HANDLE_TYPE_RIGHT, CD_PROP_INT8)) {
-      types_right = {static_cast<int8_t *>(layer.data), this->points_num()};
-      continue;
+    if (id.is_named() && bezier_handle_names.contains(id.name())) {
+      return true;
     }
 
-    const eCustomDataType data_type = static_cast<eCustomDataType>(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<T>(
-          *this, curves_to_reverse, {static_cast<T *>(layer.data), this->points_num()});
+      reverse_curve_point_data<T>(*this, curves_to_reverse, attribute.span.typed<T>());
     });
-  }
+    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();
@@ -1450,21 +1440,20 @@ 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);
   }
 }
 
diff --git a/source/blender/blenkernel/intern/customdata.cc b/source/blender/blenkernel/intern/customdata.cc
index a5c93e205b9..bf56fb7f044 100644
--- a/source/blender/blenkernel/intern/customdata.cc
+++ b/source/blender/blenkernel/intern/customdata.cc
@@ -2415,19 +2415,37 @@ bool CustomData_merge_mesh_to_bmesh(const CustomData *source,
   return result;
 }
 
-void CustomData_realloc(CustomData *data, const int totelem)
+void CustomData_realloc(CustomData *data, const int old_size, const int new_size)
 {
-  BLI_assert(totelem >= 0);
+  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);
   }
 }
 
diff --git a/source/blender/blenkernel/intern/image_save.cc b/source/blender/blenkernel/intern/image_save.cc
index e65a94d5301..6f62ee123cb 100644
--- a/source/blender/blenkernel/intern/image_save.cc
+++ b/source/blender/blenkernel/intern/image_save.cc
@@ -175,12 +175,12 @@ bool BKE_image_save_options_init(ImageSaveOptions *opts,
           BLI_strncpy(opts->filepath, G.ima, sizeof(opts->filepath));
         }
         else {
-          BLI_snprintf(opts->filepath, sizeof(opts->filepath), "//%s", DATA_("untitled"));
+          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));
       }
diff --git a/source/blender/blenkernel/intern/mesh.cc b/source/blender/blenkernel/intern/mesh.cc
index 965c8487f9a..58397da202f 100644
--- a/source/blender/blenkernel/intern/mesh.cc
+++ b/source/blender/blenkernel/intern/mesh.cc
@@ -1414,19 +1414,15 @@ void BKE_mesh_material_remap(Mesh *me, const uint *remap, uint remap_len)
   }
   else {
     MutableAttributeAccessor attributes = me->attributes_for_write();
-    AttributeWriter<int> material_indices = attributes.lookup_for_write<int>("material_index");
+    SpanAttributeWriter<int> material_indices = attributes.lookup_or_add_for_write_span<int>(
+        "material_index", ATTR_DOMAIN_FACE);
     if (!material_indices) {
       return;
     }
-    if (material_indices.domain != ATTR_DOMAIN_FACE) {
-      BLI_assert_unreachable();
-      return;
-    }
-    MutableVArraySpan<int> indices_span(material_indices.varray);
-    for (const int i : indices_span.index_range()) {
-      MAT_NR_REMAP(indices_span[i]);
+    for (const int i : material_indices.span.index_range()) {
+      MAT_NR_REMAP(material_indices.span[i]);
     }
-    indices_span.save();
+    material_indices.span.save();
     material_indices.finish();
   }
 
@@ -2081,11 +2077,11 @@ 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 normals manually to avoid recalculation after this operation. */
diff --git a/source/blender/blenkernel/intern/mesh_convert.cc b/source/blender/blenkernel/intern/mesh_convert.cc
index d57212e3d6d..0ae6e1e4a1f 100644
--- a/source/blender/blenkernel/intern/mesh_convert.cc
+++ b/source/blender/blenkernel/intern/mesh_convert.cc
@@ -105,8 +105,9 @@ static void make_edges_mdata_extend(Mesh &mesh)
 #endif
 
   if (totedge_new) {
-    CustomData_realloc(&mesh.edata, totedge + 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<MEdge> edges = mesh.edges_for_write();
     MEdge *medge = &edges[totedge];
@@ -629,9 +630,11 @@ void BKE_pointcloud_from_mesh(Mesh *me, PointCloud *pointcloud)
   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);
diff --git a/source/blender/blenkernel/intern/nla.c b/source/blender/blenkernel/intern/nla.c
index 9457c20eb7d..da508ff865c 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) {
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.cc b/source/blender/blenkernel/intern/paint.cc
index ca09567cb6b..ce004b6664a 100644
--- a/source/blender/blenkernel/intern/paint.cc
+++ b/source/blender/blenkernel/intern/paint.cc
@@ -1089,10 +1089,10 @@ bool BKE_paint_ensure(ToolSettings *ts, Paint **r_paint)
     Sculpt *data = MEM_cnew<Sculpt>(__func__);
     paint = &data->paint;
 
-    /* Turn on X plane mirror symmetry by default */
+    /* Turn on X plane mirror symmetry by default. */
     paint->symmetry_flags |= PAINT_SYMM_X;
 
-    /* Make sure at least dyntopo subdivision is enabled */
+    /* Make sure at least dyntopo subdivision is enabled. */
     data->flags |= SCULPT_DYNTOPO_SUBDIVIDE | SCULPT_DYNTOPO_COLLAPSE;
   }
   else if ((GpPaint **)r_paint == &ts->gp_paint) {
@@ -1147,7 +1147,7 @@ void BKE_paint_init(Main *bmain, Scene *sce, ePaintMode mode, const uchar col[3]
       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 */
+        id_us_min(&brush->id); /* Fake user only. */
       }
       BKE_paint_brush_set(paint, brush);
     }
@@ -1248,18 +1248,17 @@ void BKE_paint_blend_read_lib(BlendLibReader *reader, Scene *sce, Paint *p)
   }
 }
 
-bool paint_is_face_hidden(const MLoopTri *lt, const bool *hide_vert, const MLoop *mloop)
+bool paint_is_face_hidden(const MLoopTri *lt, const bool *hide_poly)
 {
-  if (!hide_vert) {
+  if (!hide_poly) {
     return false;
   }
-  return ((hide_vert[mloop[lt->tri[0]].v]) || (hide_vert[mloop[lt->tri[1]].v]) ||
-          (hide_vert[mloop[lt->tri[2]].v]));
+  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 */
+  /* 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) ||
@@ -1289,7 +1288,7 @@ float paint_grid_paint_mask(const GridPaintMask *gpm, uint level, uint x, uint y
   return gpm->data[(y * factor) * gridsize + (x * factor)];
 }
 
-/* threshold to move before updating the brush rotation */
+/* Threshold to move before updating the brush rotation. */
 #define RAKE_THRESHHOLD 20
 
 void paint_update_brush_rake_rotation(UnifiedPaintSettings *ups, Brush *brush, float rotation)
@@ -1332,8 +1331,8 @@ bool paint_calculate_rake_rotation(UnifiedPaintSettings *ups,
       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 */
+    /* 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;
@@ -1529,20 +1528,29 @@ void BKE_sculptsession_free(Object *ob)
   }
 }
 
-MultiresModifierData *BKE_sculpt_multires_active(const Scene *scene, Object *ob)
+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 */
+    /* Can't combine multires and dynamic topology. */
     return nullptr;
   }
 
+  bool need_mdisps = false;
+
   if (!CustomData_get_layer(&me->ldata, CD_MDISPS)) {
-    /* multires can't work without displacement layer */
-    return nullptr;
+    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
@@ -1560,6 +1568,10 @@ MultiresModifierData *BKE_sculpt_multires_active(const Scene *scene, Object *ob)
       }
 
       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;
       }
 
@@ -1570,6 +1582,11 @@ MultiresModifierData *BKE_sculpt_multires_active(const Scene *scene, Object *ob)
   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)
 {
@@ -1581,14 +1598,14 @@ static bool sculpt_modifiers_active(Scene *scene, Sculpt *sd, Object *ob)
     return false;
   }
 
-  /* non-locked shape keys could be handled in the same way as deformed mesh */
+  /* 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 */
+  /* Exception for shape keys because we can edit those. */
   for (; md; md = md->next) {
     const ModifierTypeInfo *mti = BKE_modifier_get_info(static_cast<ModifierType>(md->type));
     if (!BKE_modifier_is_enabled(scene, md, eModifierMode_Realtime)) {
@@ -1615,22 +1632,15 @@ static bool sculpt_modifiers_active(Scene *scene, Sculpt *sd, Object *ob)
   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,
-                                 Object *ob_eval,
-                                 bool need_pmap,
-                                 bool need_mask,
-                                 bool is_paint_tool)
+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 = BKE_sculpt_multires_active(scene, ob);
+  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);
@@ -1645,15 +1655,6 @@ static void sculpt_update_object(Depsgraph *depsgraph,
 
   ss->scene = scene;
 
-  if (need_mask) {
-    if (mmd == nullptr) {
-      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 == nullptr) ? BKE_keyblock_from_object(ob) : nullptr;
 
   /* NOTE: Weight pPaint require mesh info for loop lookup, but it never uses multires code path,
@@ -1709,7 +1710,6 @@ static void sculpt_update_object(Depsgraph *depsgraph,
 
   /* Sculpt Face Sets. */
   if (use_face_sets) {
-    BLI_assert(CustomData_has_layer(&me->pdata, CD_SCULPT_FACE_SETS));
     ss->face_sets = static_cast<int *>(CustomData_get_layer(&me->pdata, CD_SCULPT_FACE_SETS));
   }
   else {
@@ -1842,24 +1842,7 @@ static void sculpt_update_object(Depsgraph *depsgraph,
   }
 }
 
-static void sculpt_face_sets_ensure(Mesh *mesh)
-{
-  if (CustomData_has_layer(&mesh->pdata, CD_SCULPT_FACE_SETS)) {
-    return;
-  }
-
-  int *new_face_sets = static_cast<int *>(CustomData_add_layer(
-      &mesh->pdata, CD_SCULPT_FACE_SETS, CD_CONSTRUCT, nullptr, 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)
+void BKE_sculpt_update_object_before_eval(Object *ob_eval)
 {
   /* Update before mesh evaluation in the dependency graph. */
   SculptSession *ss = ob_eval->sculpt;
@@ -1889,16 +1872,6 @@ void BKE_sculpt_update_object_before_eval(const Scene *scene, Object *ob_eval)
       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)
@@ -1907,7 +1880,7 @@ void BKE_sculpt_update_object_after_eval(Depsgraph *depsgraph, Object *ob_eval)
    * 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, false);
+  sculpt_update_object(depsgraph, ob_orig, ob_eval, false, false);
 }
 
 void BKE_sculpt_color_layer_create_if_needed(Object *object)
@@ -1945,13 +1918,53 @@ void BKE_sculpt_color_layer_create_if_needed(Object *object)
 }
 
 void BKE_sculpt_update_object_for_edit(
-    Depsgraph *depsgraph, Object *ob_orig, bool need_pmap, bool need_mask, bool is_paint_tool)
+    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, need_mask, is_paint_tool);
+  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<int *>(CustomData_get_layer(&mesh->pdata, CD_SCULPT_FACE_SETS));
+  }
+
+  const AttributeAccessor attributes = mesh->attributes_for_write();
+  const VArray<bool> hide_poly = attributes.lookup_or_default<bool>(
+      ".hide_poly", ATTR_DOMAIN_FACE, false);
+
+  MutableSpan<int> face_sets = {
+      static_cast<int *>(CustomData_add_layer(
+          &mesh->pdata, CD_SCULPT_FACE_SETS, CD_CONSTRUCT, nullptr, mesh->totpoly)),
+      mesh->totpoly};
+
+  /* Initialize the new face sets with a default valid visible ID and set the default
+   * color to render it white. */
+  if (hide_poly.is_single() && !hide_poly.get_internal_single()) {
+    face_sets.fill(1);
+  }
+  else {
+    const int face_sets_default_visible_id = 1;
+    const int face_sets_default_hidden_id = -2;
+
+    const VArraySpan<bool> hide_poly_span{hide_poly};
+    for (const int i : face_sets.index_range()) {
+      /* Assign a new hidden ID to hidden faces. This way we get at initial split in two Face Sets
+       * between hidden and visible faces based on the previous mesh visibly from other mode that
+       * can be useful in some cases. */
+      face_sets[i] = hide_poly_span[i] ? face_sets_default_hidden_id :
+                                         face_sets_default_visible_id;
+    }
+  }
+
+  mesh->face_sets_color_default = 1;
+  return face_sets.data();
 }
 
 int BKE_sculpt_mask_layers_ensure(Object *ob, MultiresModifierData *mmd)
@@ -2015,7 +2028,7 @@ int BKE_sculpt_mask_layers_ensure(Object *ob, MultiresModifierData *mmd)
     ret |= SCULPT_MASK_LAYER_CALC_LOOP;
   }
 
-  /* create vertex paint mask layer if there isn't one already */
+  /* 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);
     ret |= SCULPT_MASK_LAYER_CALC_VERT;
@@ -2039,7 +2052,7 @@ void BKE_sculpt_toolsettings_data_ensure(Scene *scene)
     sd->constant_detail = 3.0f;
   }
 
-  /* Set sane default tiling offsets */
+  /* Set sane default tiling offsets. */
   if (!sd->paint.tile_offset[0]) {
     sd->paint.tile_offset[0] = 1.0f;
   }
@@ -2057,8 +2070,7 @@ static bool check_sculpt_object_deformed(Object *object, const bool for_construc
 
   /* 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.
-   */
+   * stuff and show final evaluated mesh so user would see actual object shape. */
   deformed |= object->sculpt->deform_modifiers_active;
 
   if (for_construction) {
@@ -2067,75 +2079,55 @@ static bool check_sculpt_object_deformed(Object *object, const bool for_construc
   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.
-     */
+     * 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)
+void BKE_sculpt_face_sets_update_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 = static_cast<int *>(
-        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 = static_cast<int *>(CustomData_add_layer(
-        &mesh->pdata, CD_SCULPT_FACE_SETS, CD_CONSTRUCT, nullptr, 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;
+  using namespace blender;
+  using namespace blender::bke;
+  if (!CustomData_has_layer(&mesh->pdata, CD_SCULPT_FACE_SETS)) {
+    return;
   }
 
-  int *face_sets = static_cast<int *>(CustomData_get_layer(&mesh->pdata, CD_SCULPT_FACE_SETS));
-  const bool *hide_poly = (const bool *)CustomData_get_layer_named(
-      &mesh->pdata, CD_PROP_BOOL, ".hide_poly");
+  const AttributeAccessor attributes = mesh->attributes();
+  const VArray<bool> hide_poly = attributes.lookup_or_default<bool>(
+      ".hide_poly", ATTR_DOMAIN_FACE, false);
+  if (hide_poly.is_single() && !hide_poly.get_internal_single()) {
+    return;
+  }
 
-  for (int i = 0; i < mesh->totpoly; i++) {
-    if (!(hide_poly && hide_poly[i])) {
-      continue;
-    }
+  MutableSpan<int> face_sets{
+      static_cast<int *>(CustomData_get_layer(&mesh->pdata, CD_SCULPT_FACE_SETS)), mesh->totpoly};
 
-    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]);
-    }
+  for (const int i : hide_poly.index_range()) {
+    face_sets[i] = hide_poly[i] ? -std::abs(face_sets[i]) : std::abs(face_sets[i]);
   }
 }
 
-void BKE_sculpt_sync_face_sets_visibility_to_base_mesh(Mesh *mesh)
+static void set_hide_poly_from_face_sets(Mesh &mesh)
 {
+  using namespace blender;
   using namespace blender::bke;
-  const int *face_sets = static_cast<const int *>(
-      CustomData_get_layer(&mesh->pdata, CD_SCULPT_FACE_SETS));
-  if (!face_sets) {
+  if (!CustomData_has_layer(&mesh.pdata, CD_SCULPT_FACE_SETS)) {
+    return;
+  }
+
+  const Span<int> face_sets{
+      static_cast<const int *>(CustomData_get_layer(&mesh.pdata, CD_SCULPT_FACE_SETS)),
+      mesh.totpoly};
+
+  MutableAttributeAccessor attributes = mesh.attributes_for_write();
+  if (std::all_of(
+          face_sets.begin(), face_sets.end(), [&](const int value) { return value > 0; })) {
+    attributes.remove(".hide_poly");
     return;
   }
 
-  MutableAttributeAccessor attributes = mesh->attributes_for_write();
   SpanAttributeWriter<bool> hide_poly = attributes.lookup_or_add_for_write_only_span<bool>(
       ".hide_poly", ATTR_DOMAIN_FACE);
   if (!hide_poly) {
@@ -2145,7 +2137,11 @@ void BKE_sculpt_sync_face_sets_visibility_to_base_mesh(Mesh *mesh)
     hide_poly.span[i] = face_sets[i] < 0;
   }
   hide_poly.finish();
+}
 
+void BKE_sculpt_sync_face_sets_visibility_to_base_mesh(Mesh *mesh)
+{
+  set_hide_poly_from_face_sets(*mesh);
   BKE_mesh_flush_hidden_from_polys(mesh);
 }
 
@@ -2183,41 +2179,29 @@ void BKE_sculpt_sync_face_sets_visibility_to_grids(Mesh *mesh, SubdivCCG *subdiv
 
 void BKE_sculpt_sync_face_set_visibility(Mesh *mesh, SubdivCCG *subdiv_ccg)
 {
-  BKE_sculpt_face_sets_ensure_from_base_mesh_visibility(mesh);
+  BKE_sculpt_face_sets_update_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)
+void BKE_sculpt_ensure_orig_mesh_data(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 != nullptr) {
-    /* If a sculpt session is active, ensure we have its face-set data properly up-to-date. */
-    object->sculpt->face_sets = static_cast<int *>(
-        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);
-  }
+  BKE_sculpt_face_sets_update_from_base_mesh_visibility(mesh);
 
   /* 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
+   * `BKE_sculpt_face_sets_update_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`).
+   *     (`BKE_sculpt_face_sets_update_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:
diff --git a/source/blender/blenkernel/intern/pbvh.c b/source/blender/blenkernel/intern/pbvh.c
index b1cb8862776..d63a52c383c 100644
--- a/source/blender/blenkernel/intern/pbvh.c
+++ b/source/blender/blenkernel/intern/pbvh.c
@@ -285,7 +285,7 @@ static void build_mesh_leaf_node(PBVH *pbvh, PBVHNode *node)
     }
 
     if (has_visible == false) {
-      if (!paint_is_face_hidden(lt, pbvh->hide_vert, pbvh->mloop)) {
+      if (!paint_is_face_hidden(lt, pbvh->hide_poly)) {
         has_visible = true;
       }
     }
@@ -552,6 +552,7 @@ void BKE_pbvh_build_mesh(PBVH *pbvh,
   pbvh->mesh = mesh;
   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;
@@ -1313,11 +1314,7 @@ static void pbvh_update_draw_buffer_cb(void *__restrict userdata,
       }
       case PBVH_FACES:
         node->draw_buffers = GPU_pbvh_mesh_buffers_build(
-            pbvh->mesh,
-            pbvh->looptri,
-            CustomData_get_layer(pbvh->pdata, CD_SCULPT_FACE_SETS),
-            node->prim_indices,
-            node->totprim);
+            pbvh->mesh, pbvh->looptri, node->prim_indices, node->totprim);
         break;
       case PBVH_BMESH:
         node->draw_buffers = GPU_pbvh_bmesh_buffers_build(pbvh->flags &
@@ -2282,7 +2279,7 @@ 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, pbvh->hide_vert, mloop)) {
+    if (pbvh->respect_hide && paint_is_face_hidden(lt, pbvh->hide_poly)) {
       continue;
     }
 
@@ -2591,7 +2588,7 @@ 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, pbvh->hide_vert, mloop)) {
+    if (pbvh->respect_hide && paint_is_face_hidden(lt, pbvh->hide_poly)) {
       continue;
     }
 
@@ -3202,6 +3199,12 @@ const bool *BKE_pbvh_get_vert_hide(const PBVH *pbvh)
   return pbvh->hide_vert;
 }
 
+const bool *BKE_pbvh_get_poly_hide(const PBVH *pbvh)
+{
+  BLI_assert(pbvh->header.type == PBVH_FACES);
+  return pbvh->hide_poly;
+}
+
 bool *BKE_pbvh_get_vert_hide_for_write(PBVH *pbvh)
 {
   BLI_assert(pbvh->header.type == PBVH_FACES);
diff --git a/source/blender/blenkernel/intern/pbvh_intern.h b/source/blender/blenkernel/intern/pbvh_intern.h
index 91533994932..00681e31c10 100644
--- a/source/blender/blenkernel/intern/pbvh_intern.h
+++ b/source/blender/blenkernel/intern/pbvh_intern.h
@@ -156,6 +156,7 @@ struct PBVH {
   bool *hide_vert;
   float (*positions)[3];
   const struct MPoly *mpoly;
+  bool *hide_poly;
   /** Material indices. Only valid for polygon meshes. */
   const int *material_indices;
   const struct MLoop *mloop;
diff --git a/source/blender/blenkernel/intern/pointcloud.cc b/source/blender/blenkernel/intern/pointcloud.cc
index fe6353bc72d..b45e164b594 100644
--- a/source/blender/blenkernel/intern/pointcloud.cc
+++ b/source/blender/blenkernel/intern/pointcloud.cc
@@ -189,8 +189,9 @@ IDTypeInfo IDType_ID_PT = {
 
 static void pointcloud_random(PointCloud *pointcloud)
 {
+  BLI_assert(pointcloud->totpoint == 0);
   pointcloud->totpoint = 400;
-  CustomData_realloc(&pointcloud->pdata, pointcloud->totpoint);
+  CustomData_realloc(&pointcloud->pdata, 0, pointcloud->totpoint);
 
   RNG *rng = BLI_rng_new(0);
 
@@ -238,9 +239,6 @@ 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_SET_DEFAULT,
@@ -248,8 +246,8 @@ PointCloud *BKE_pointcloud_new_nomain(const int totpoint)
                              pointcloud->totpoint,
                              POINTCLOUD_ATTR_RADIUS);
 
+  CustomData_realloc(&pointcloud->pdata, 0, totpoint);
   pointcloud->totpoint = totpoint;
-  CustomData_realloc(&pointcloud->pdata, pointcloud->totpoint);
 
   return pointcloud;
 }
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<int64_t>(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<int64_t>(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<int64_t>(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<int64_t>(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<int64_t>(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<int64_t>(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<int64_t>(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<int64_t>(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_path_util.h b/source/blender/blenlib/BLI_path_util.h
index 75002f52d94..136258e50f2 100644
--- a/source/blender/blenlib/BLI_path_util.h
+++ b/source/blender/blenlib/BLI_path_util.h
@@ -84,10 +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()`
diff --git a/source/blender/blenlib/intern/path_util.c b/source/blender/blenlib/intern/path_util.c
index 1e95aa3b7b0..c053c3907db 100644
--- a/source/blender/blenlib/intern/path_util.c
+++ b/source/blender/blenlib/intern/path_util.c
@@ -1505,8 +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/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/compositor/operations/COM_ViewerOperation.cc b/source/blender/compositor/operations/COM_ViewerOperation.cc
index aeadf8f255d..3bd5fa4ad14 100644
--- a/source/blender/compositor/operations/COM_ViewerOperation.cc
+++ b/source/blender/compositor/operations/COM_ViewerOperation.cc
@@ -156,7 +156,7 @@ void ViewerOperation::init_image()
     ibuf->y = display_height_;
     /* zero size can happen if no image buffers exist to define a sensible resolution */
     if (ibuf->x > 0 && ibuf->y > 0) {
-      imb_addrectfloatImBuf(ibuf);
+      imb_addrectfloatImBuf(ibuf, 4);
     }
 
     ibuf->userflags |= IB_DISPLAY_BUFFER_INVALID;
diff --git a/source/blender/draw/intern/draw_cache_impl_mesh.cc b/source/blender/draw/intern/draw_cache_impl_mesh.cc
index e60689f0237..c22382b3e09 100644
--- a/source/blender/draw/intern/draw_cache_impl_mesh.cc
+++ b/source/blender/draw/intern/draw_cache_impl_mesh.cc
@@ -556,8 +556,7 @@ static bool mesh_batch_cache_valid(Object *object, Mesh *me)
   }
 
   if (object->sculpt && object->sculpt->pbvh) {
-    if (cache->pbvh_is_drawing != BKE_pbvh_is_drawing(object->sculpt->pbvh) ||
-        BKE_pbvh_draw_cache_invalid(object->sculpt->pbvh)) {
+    if (cache->pbvh_is_drawing != BKE_pbvh_is_drawing(object->sculpt->pbvh)) {
       return false;
     }
 
diff --git a/source/blender/editors/gpencil/gpencil_edit.c b/source/blender/editors/gpencil/gpencil_edit.c
index 89ab9eda7f0..d28cefd4887 100644
--- a/source/blender/editors/gpencil/gpencil_edit.c
+++ b/source/blender/editors/gpencil/gpencil_edit.c
@@ -67,6 +67,7 @@
 
 #include "ED_armature.h"
 #include "ED_gpencil.h"
+#include "ED_keyframing.h"
 #include "ED_object.h"
 #include "ED_outliner.h"
 #include "ED_screen.h"
@@ -1715,10 +1716,15 @@ static int gpencil_strokes_paste_exec(bContext *C, wmOperator *op)
 
         /* Ensure we have a frame to draw into
          * NOTE: Since this is an op which creates strokes,
-         *       we are obliged to add a new frame if one
-         *       doesn't exist already
+         *       we resuse active frame or add a new frame if one
+         *       doesn't exist already depending on REC button status.
          */
-        gpf = BKE_gpencil_layer_frame_get(gpl, scene->r.cfra, GP_GETFRAME_ADD_NEW);
+        if (IS_AUTOKEY_ON(scene) || (gpl->actframe == NULL)) {
+          gpf = BKE_gpencil_layer_frame_get(gpl, scene->r.cfra, GP_GETFRAME_ADD_NEW);
+        }
+        else {
+          gpf = BKE_gpencil_layer_frame_get(gpl, scene->r.cfra, GP_GETFRAME_USE_PREV);
+        }
         if (gpf) {
           /* Create new stroke */
           bGPDstroke *new_stroke = BKE_gpencil_stroke_duplicate(gps, true, true);
diff --git a/source/blender/editors/include/ED_mesh.h b/source/blender/editors/include/ED_mesh.h
index b6a652bd3ab..26743a2bd08 100644
--- a/source/blender/editors/include/ED_mesh.h
+++ b/source/blender/editors/include/ED_mesh.h
@@ -139,6 +139,7 @@ struct UvElementMap *BM_uv_element_map_create(struct BMesh *bm,
                                               const struct Scene *scene,
                                               bool uv_selected,
                                               bool use_winding,
+                                              bool use_seams,
                                               bool do_islands);
 void BM_uv_element_map_free(struct UvElementMap *element_map);
 struct UvElement *BM_uv_element_get(const struct UvElementMap *map,
diff --git a/source/blender/editors/io/io_obj.c b/source/blender/editors/io/io_obj.c
index 66e95c019f6..619d8a34132 100644
--- a/source/blender/editors/io/io_obj.c
+++ b/source/blender/editors/io/io_obj.c
@@ -125,7 +125,7 @@ static void ui_obj_export_settings(uiLayout *layout, PointerRNA *imfptr)
   uiItemR(sub, imfptr, "scaling_factor", 0, NULL, ICON_NONE);
 
   row = uiLayoutRow(box, false);
-  uiItemR(row, imfptr, "forward_axis", UI_ITEM_R_EXPAND, IFACE_("Foward Axis"), ICON_NONE);
+  uiItemR(row, imfptr, "forward_axis", UI_ITEM_R_EXPAND, IFACE_("Forward Axis"), ICON_NONE);
   row = uiLayoutRow(box, false);
   uiItemR(row, imfptr, "up_axis", UI_ITEM_R_EXPAND, IFACE_("Up Axis"), ICON_NONE);
 
diff --git a/source/blender/editors/io/io_usd.c b/source/blender/editors/io/io_usd.c
index ba118a5e289..eb80cabcd7f 100644
--- a/source/blender/editors/io/io_usd.c
+++ b/source/blender/editors/io/io_usd.c
@@ -191,6 +191,19 @@ static void wm_usd_export_draw(bContext *UNUSED(C), wmOperator *op)
   uiItemR(box, ptr, "use_instancing", 0, NULL, ICON_NONE);
 }
 
+static void free_operator_customdata(wmOperator *op)
+{
+  if (op->customdata) {
+    MEM_freeN(op->customdata);
+    op->customdata = NULL;
+  }
+}
+
+static void wm_usd_export_cancel(bContext *UNUSED(C), wmOperator *op)
+{
+  free_operator_customdata(op);
+}
+
 static bool wm_usd_export_check(bContext *UNUSED(C), wmOperator *op)
 {
   char filepath[FILE_MAX];
@@ -215,6 +228,7 @@ void WM_OT_usd_export(struct wmOperatorType *ot)
   ot->exec = wm_usd_export_exec;
   ot->poll = WM_operator_winactive;
   ot->ui = wm_usd_export_draw;
+  ot->cancel = wm_usd_export_cancel;
   ot->check = wm_usd_export_check;
 
   ot->flag = OPTYPE_REGISTER | OPTYPE_PRESET; /* No UNDO possible. */
@@ -360,7 +374,7 @@ static int wm_usd_import_exec(bContext *C, wmOperator *op)
 
   const bool create_collection = RNA_boolean_get(op->ptr, "create_collection");
 
-  char *prim_path_mask = malloc(1024);
+  char prim_path_mask[1024];
   RNA_string_get(op->ptr, "prim_path_mask", prim_path_mask);
 
   const bool import_guide = RNA_boolean_get(op->ptr, "import_guide");
@@ -402,7 +416,6 @@ static int wm_usd_import_exec(bContext *C, wmOperator *op)
                                    .import_materials = import_materials,
                                    .import_meshes = import_meshes,
                                    .import_volumes = import_volumes,
-                                   .prim_path_mask = prim_path_mask,
                                    .import_subdiv = import_subdiv,
                                    .import_instance_proxies = import_instance_proxies,
                                    .create_collection = create_collection,
@@ -416,11 +429,18 @@ static int wm_usd_import_exec(bContext *C, wmOperator *op)
                                    .light_intensity_scale = light_intensity_scale,
                                    .mtl_name_collision_mode = mtl_name_collision_mode};
 
+  STRNCPY(params.prim_path_mask, prim_path_mask);
+
   const bool ok = USD_import(C, filename, &params, as_background_job);
 
   return as_background_job || ok ? OPERATOR_FINISHED : OPERATOR_CANCELLED;
 }
 
+static void wm_usd_import_cancel(bContext *UNUSED(C), wmOperator *op)
+{
+  free_operator_customdata(op);
+}
+
 static void wm_usd_import_draw(bContext *UNUSED(C), wmOperator *op)
 {
   uiLayout *layout = op->layout;
@@ -476,6 +496,7 @@ void WM_OT_usd_import(struct wmOperatorType *ot)
 
   ot->invoke = wm_usd_import_invoke;
   ot->exec = wm_usd_import_exec;
+  ot->cancel = wm_usd_import_cancel;
   ot->poll = WM_operator_winactive;
   ot->ui = wm_usd_import_draw;
 
diff --git a/source/blender/editors/mesh/editmesh_utils.c b/source/blender/editors/mesh/editmesh_utils.c
index a6a6b095c31..cca2aa11ac3 100644
--- a/source/blender/editors/mesh/editmesh_utils.c
+++ b/source/blender/editors/mesh/editmesh_utils.c
@@ -851,10 +851,99 @@ static void bm_uv_build_islands(UvElementMap *element_map,
   MEM_SAFE_FREE(map);
 }
 
+/* return true if `loop` has UV co-ordinates which match `luv_a` and `luv_b` */
+static bool loop_uv_match(BMLoop *loop, MLoopUV *luv_a, MLoopUV *luv_b, int cd_loop_uv_offset)
+{
+  MLoopUV *luv_c = BM_ELEM_CD_GET_VOID_P(loop, cd_loop_uv_offset);
+  MLoopUV *luv_d = BM_ELEM_CD_GET_VOID_P(loop->next, cd_loop_uv_offset);
+  return compare_v2v2(luv_a->uv, luv_c->uv, STD_UV_CONNECT_LIMIT) &&
+         compare_v2v2(luv_b->uv, luv_d->uv, STD_UV_CONNECT_LIMIT);
+}
+
+/* Given `anchor` and `edge`, return true if there are edges that fan between them that are
+ * seam-free. */
+static bool seam_connected_recursive(BMVert *anchor,
+                                     BMEdge *edge,
+                                     MLoopUV *luv_anchor,
+                                     MLoopUV *luv_fan,
+                                     BMLoop *needle,
+                                     GSet *visited,
+                                     int cd_loop_uv_offset)
+{
+  BLI_assert(edge->v1 == anchor || edge->v2 == anchor);
+  BLI_assert(needle->v == anchor || needle->next->v == anchor);
+
+  if (BM_elem_flag_test(edge, BM_ELEM_SEAM)) {
+    return false; /* Edge is a seam, don't traverse. */
+  }
+
+  if (!BLI_gset_add(visited, edge)) {
+    return false; /* Already visited. */
+  }
+
+  BMLoop *loop;
+  BMIter liter;
+  BM_ITER_ELEM (loop, &liter, edge, BM_LOOPS_OF_EDGE) {
+    if (loop->v == anchor) {
+      if (!loop_uv_match(loop, luv_anchor, luv_fan, cd_loop_uv_offset)) {
+        continue; /* `loop` is disjoint in UV space. */
+      }
+
+      if (loop->prev == needle) {
+        return true; /* Success. */
+      }
+
+      MLoopUV *luv_far = BM_ELEM_CD_GET_VOID_P(loop->prev, cd_loop_uv_offset);
+      if (seam_connected_recursive(
+              anchor, loop->prev->e, luv_anchor, luv_far, needle, visited, cd_loop_uv_offset)) {
+        return true;
+      }
+    }
+    else {
+      BLI_assert(loop->next->v == anchor);
+      if (!loop_uv_match(loop, luv_fan, luv_anchor, cd_loop_uv_offset)) {
+        continue; /* `loop` is disjoint in UV space. */
+      }
+
+      if (loop->next == needle) {
+        return true; /* Success. */
+      }
+
+      MLoopUV *luv_far = BM_ELEM_CD_GET_VOID_P(loop->next->next, cd_loop_uv_offset);
+      if (seam_connected_recursive(
+              anchor, loop->next->e, luv_anchor, luv_far, needle, visited, cd_loop_uv_offset)) {
+        return true;
+      }
+    }
+  }
+
+  return false;
+}
+
+/* Given `loop_a` and `loop_b` originate from the same vertex and share a UV,
+ * return true if there are edges that fan between them that are seam-free.
+ * return false otherwise.
+ */
+static bool seam_connected(BMLoop *loop_a, BMLoop *loop_b, GSet *visited, int cd_loop_uv_offset)
+{
+  BLI_assert(loop_a && loop_b);
+  BLI_assert(loop_a != loop_b);
+  BLI_assert(loop_a->v == loop_b->v);
+
+  BLI_gset_clear(visited, NULL);
+
+  MLoopUV *luv_anchor = BM_ELEM_CD_GET_VOID_P(loop_a, cd_loop_uv_offset);
+  MLoopUV *luv_fan = BM_ELEM_CD_GET_VOID_P(loop_a->next, cd_loop_uv_offset);
+  const bool result = seam_connected_recursive(
+      loop_a->v, loop_a->e, luv_anchor, luv_fan, loop_b, visited, cd_loop_uv_offset);
+  return result;
+}
+
 UvElementMap *BM_uv_element_map_create(BMesh *bm,
                                        const Scene *scene,
                                        const bool uv_selected,
                                        const bool use_winding,
+                                       const bool use_seams,
                                        const bool do_islands)
 {
   /* In uv sync selection, all UVs are visible. */
@@ -956,6 +1045,8 @@ UvElementMap *BM_uv_element_map_create(BMesh *bm,
   }
   BLI_buffer_free(&tf_uv_buf);
 
+  GSet *seam_visited_gset = use_seams ? BLI_gset_ptr_new(__func__) : NULL;
+
   /* For each BMVert, sort associated linked list into unique uvs. */
   int ev_index;
   BM_ITER_MESH_INDEX (ev, &iter, bm, BM_VERTS_OF_MESH, ev_index) {
@@ -1001,6 +1092,10 @@ UvElementMap *BM_uv_element_map_create(BMesh *bm,
                       winding[BM_elem_index_get(v->l->f)];
         }
 
+        if (connected && use_seams) {
+          connected = seam_connected(iterv->l, v->l, seam_visited_gset, cd_loop_uv_offset);
+        }
+
         if (connected) {
           if (lastv) {
             lastv->next = next;
@@ -1026,6 +1121,10 @@ UvElementMap *BM_uv_element_map_create(BMesh *bm,
     element_map->vertex[ev_index] = newvlist;
   }
 
+  if (seam_visited_gset) {
+    BLI_gset_free(seam_visited_gset, NULL);
+    seam_visited_gset = NULL;
+  }
   MEM_SAFE_FREE(winding);
 
   /* at this point, every UvElement in vert points to a UvElement sharing the same vertex.
diff --git a/source/blender/editors/object/object_remesh.cc b/source/blender/editors/object/object_remesh.cc
index c85c8f9535a..2fb6257885c 100644
--- a/source/blender/editors/object/object_remesh.cc
+++ b/source/blender/editors/object/object_remesh.cc
@@ -186,7 +186,7 @@ static int voxel_remesh_exec(bContext *C, wmOperator *op)
   }
 
   if (ob->mode == OB_MODE_SCULPT) {
-    BKE_sculpt_ensure_orig_mesh_data(CTX_data_scene(C), ob);
+    BKE_sculpt_ensure_orig_mesh_data(ob);
     ED_sculpt_undo_geometry_end(ob);
   }
 
@@ -910,7 +910,7 @@ static void quadriflow_start_job(void *customdata, short *stop, short *do_update
   }
 
   if (ob->mode == OB_MODE_SCULPT) {
-    BKE_sculpt_ensure_orig_mesh_data(qj->scene, ob);
+    BKE_sculpt_ensure_orig_mesh_data(ob);
     ED_sculpt_undo_geometry_end(ob);
   }
 
diff --git a/source/blender/editors/sculpt_paint/paint_mask.c b/source/blender/editors/sculpt_paint/paint_mask.c
index 24337477585..ac7002e9e43 100644
--- a/source/blender/editors/sculpt_paint/paint_mask.c
+++ b/source/blender/editors/sculpt_paint/paint_mask.c
@@ -134,6 +134,7 @@ static void mask_flood_fill_task_cb(void *__restrict userdata,
 
 static int mask_flood_fill_exec(bContext *C, wmOperator *op)
 {
+  const Scene *scene = CTX_data_scene(C);
   Object *ob = CTX_data_active_object(C);
   Depsgraph *depsgraph = CTX_data_ensure_evaluated_depsgraph(C);
   PaintMaskFloodMode mode;
@@ -146,6 +147,9 @@ static int mask_flood_fill_exec(bContext *C, wmOperator *op)
   mode = RNA_enum_get(op->ptr, "mode");
   value = RNA_float_get(op->ptr, "value");
 
+  MultiresModifierData *mmd = BKE_sculpt_multires_active(scene, ob);
+  BKE_sculpt_mask_layers_ensure(ob, mmd);
+
   BKE_sculpt_update_object_for_edit(depsgraph, ob, false, true, false);
   pbvh = ob->sculpt->pbvh;
   multires = (BKE_pbvh_type(pbvh) == PBVH_GRIDS);
@@ -774,6 +778,8 @@ static void sculpt_gesture_init_face_set_properties(SculptGestureContext *sgcont
   struct Mesh *mesh = BKE_mesh_from_object(sgcontext->vc.obact);
   sgcontext->operation = MEM_callocN(sizeof(SculptGestureFaceSetOperation), "Face Set Operation");
 
+  sgcontext->ss->face_sets = BKE_sculpt_face_sets_ensure(mesh);
+
   SculptGestureFaceSetOperation *face_set_operation = (SculptGestureFaceSetOperation *)
                                                           sgcontext->operation;
 
@@ -817,7 +823,7 @@ static void mask_gesture_apply_task_cb(void *__restrict userdata,
 
   BKE_pbvh_vertex_iter_begin (sgcontext->ss->pbvh, node, vd, PBVH_ITER_UNIQUE) {
     if (sculpt_gesture_is_vertex_effected(sgcontext, &vd)) {
-      float prevmask = *vd.mask;
+      float prevmask = vd.mask ? *vd.mask : 0.0f;
       if (!any_masked) {
         any_masked = true;
 
@@ -863,6 +869,10 @@ static void sculpt_gesture_init_mask_properties(SculptGestureContext *sgcontext,
 
   SculptGestureMaskOperation *mask_operation = (SculptGestureMaskOperation *)sgcontext->operation;
 
+  Object *object = sgcontext->vc.obact;
+  MultiresModifierData *mmd = BKE_sculpt_multires_active(sgcontext->vc.scene, object);
+  BKE_sculpt_mask_layers_ensure(sgcontext->vc.obact, mmd);
+
   mask_operation->op.sculpt_gesture_begin = sculpt_gesture_mask_begin;
   mask_operation->op.sculpt_gesture_apply_for_symmetry_pass =
       sculpt_gesture_mask_apply_for_symmetry_pass;
diff --git a/source/blender/editors/sculpt_paint/sculpt.c b/source/blender/editors/sculpt_paint/sculpt.c
index 9b6ddcd4b6d..31f3ccd2175 100644
--- a/source/blender/editors/sculpt_paint/sculpt.c
+++ b/source/blender/editors/sculpt_paint/sculpt.c
@@ -253,11 +253,11 @@ float SCULPT_vertex_mask_get(SculptSession *ss, PBVHVertRef vertex)
   float *mask;
   switch (BKE_pbvh_type(ss->pbvh)) {
     case PBVH_FACES:
-      return ss->vmask[vertex.i];
+      return ss->vmask ? ss->vmask[vertex.i] : 0.0f;
     case PBVH_BMESH:
       v = (BMVert *)vertex.i;
       mask = BM_ELEM_CD_GET_VOID_P(v, CustomData_get_offset(&ss->bm->vdata, CD_PAINT_MASK));
-      return *mask;
+      return mask ? *mask : 0.0f;
     case PBVH_GRIDS: {
       const CCGKey *key = BKE_pbvh_get_grid_key(ss->pbvh);
       const int grid_index = vertex.i / key->grid_area;
@@ -329,8 +329,14 @@ int SCULPT_active_face_set_get(SculptSession *ss)
 {
   switch (BKE_pbvh_type(ss->pbvh)) {
     case PBVH_FACES:
+      if (!ss->face_sets) {
+        return SCULPT_FACE_SET_NONE;
+      }
       return ss->face_sets[ss->active_face_index];
     case PBVH_GRIDS: {
+      if (!ss->face_sets) {
+        return SCULPT_FACE_SET_NONE;
+      }
       const int face_index = BKE_subdiv_ccg_grid_to_face_index(ss->subdiv_ccg,
                                                                ss->active_grid_index);
       return ss->face_sets[face_index];
@@ -383,6 +389,7 @@ bool SCULPT_vertex_visible_get(SculptSession *ss, PBVHVertRef vertex)
 
 void SCULPT_face_set_visibility_set(SculptSession *ss, int face_set, bool visible)
 {
+  BLI_assert(ss->face_sets != NULL);
   switch (BKE_pbvh_type(ss->pbvh)) {
     case PBVH_FACES:
     case PBVH_GRIDS:
@@ -405,6 +412,7 @@ void SCULPT_face_set_visibility_set(SculptSession *ss, int face_set, bool visibl
 
 void SCULPT_face_sets_visibility_invert(SculptSession *ss)
 {
+  BLI_assert(ss->face_sets != NULL);
   switch (BKE_pbvh_type(ss->pbvh)) {
     case PBVH_FACES:
     case PBVH_GRIDS:
@@ -422,6 +430,9 @@ void SCULPT_face_sets_visibility_all_set(SculptSession *ss, bool visible)
   switch (BKE_pbvh_type(ss->pbvh)) {
     case PBVH_FACES:
     case PBVH_GRIDS:
+      if (!ss->face_sets) {
+        return;
+      }
       for (int i = 0; i < ss->totfaces; i++) {
 
         /* This can run on geometry without a face set assigned, so its ID sign can't be changed to
@@ -446,11 +457,15 @@ void SCULPT_face_sets_visibility_all_set(SculptSession *ss, bool visible)
 
 bool SCULPT_vertex_any_face_set_visible_get(SculptSession *ss, PBVHVertRef vertex)
 {
+  const bool *hide_poly = BKE_pbvh_get_poly_hide(ss->pbvh);
+  if (!hide_poly) {
+    return true;
+  }
   switch (BKE_pbvh_type(ss->pbvh)) {
     case PBVH_FACES: {
       MeshElemMap *vert_map = &ss->pmap[vertex.i];
       for (int j = 0; j < ss->pmap[vertex.i].count; j++) {
-        if (ss->face_sets[vert_map->indices[j]] > 0) {
+        if (!hide_poly[vert_map->indices[j]]) {
           return true;
         }
       }
@@ -466,11 +481,15 @@ bool SCULPT_vertex_any_face_set_visible_get(SculptSession *ss, PBVHVertRef verte
 
 bool SCULPT_vertex_all_face_sets_visible_get(const SculptSession *ss, PBVHVertRef vertex)
 {
+  const bool *hide_poly = BKE_pbvh_get_poly_hide(ss->pbvh);
+  if (!hide_poly) {
+    return true;
+  }
   switch (BKE_pbvh_type(ss->pbvh)) {
     case PBVH_FACES: {
       MeshElemMap *vert_map = &ss->pmap[vertex.i];
       for (int j = 0; j < ss->pmap[vertex.i].count; j++) {
-        if (ss->face_sets[vert_map->indices[j]] < 0) {
+        if (hide_poly[vert_map->indices[j]]) {
           return false;
         }
       }
@@ -482,7 +501,7 @@ bool SCULPT_vertex_all_face_sets_visible_get(const SculptSession *ss, PBVHVertRe
       const CCGKey *key = BKE_pbvh_get_grid_key(ss->pbvh);
       const int grid_index = vertex.i / key->grid_area;
       const int face_index = BKE_subdiv_ccg_grid_to_face_index(ss->subdiv_ccg, grid_index);
-      return ss->face_sets[face_index] > 0;
+      return !hide_poly[face_index];
     }
   }
   return true;
@@ -492,6 +511,7 @@ void SCULPT_vertex_face_set_set(SculptSession *ss, PBVHVertRef vertex, int face_
 {
   switch (BKE_pbvh_type(ss->pbvh)) {
     case PBVH_FACES: {
+      BLI_assert(ss->face_sets != NULL);
       MeshElemMap *vert_map = &ss->pmap[vertex.i];
       for (int j = 0; j < ss->pmap[vertex.i].count; j++) {
         if (ss->face_sets[vert_map->indices[j]] > 0) {
@@ -502,6 +522,7 @@ void SCULPT_vertex_face_set_set(SculptSession *ss, PBVHVertRef vertex, int face_
     case PBVH_BMESH:
       break;
     case PBVH_GRIDS: {
+      BLI_assert(ss->face_sets != NULL);
       const CCGKey *key = BKE_pbvh_get_grid_key(ss->pbvh);
       const int grid_index = vertex.i / key->grid_area;
       const int face_index = BKE_subdiv_ccg_grid_to_face_index(ss->subdiv_ccg, grid_index);
@@ -517,6 +538,9 @@ int SCULPT_vertex_face_set_get(SculptSession *ss, PBVHVertRef vertex)
 {
   switch (BKE_pbvh_type(ss->pbvh)) {
     case PBVH_FACES: {
+      if (!ss->face_sets) {
+        return SCULPT_FACE_SET_NONE;
+      }
       MeshElemMap *vert_map = &ss->pmap[vertex.i];
       int face_set = 0;
       for (int i = 0; i < ss->pmap[vertex.i].count; i++) {
@@ -529,6 +553,9 @@ int SCULPT_vertex_face_set_get(SculptSession *ss, PBVHVertRef vertex)
     case PBVH_BMESH:
       return 0;
     case PBVH_GRIDS: {
+      if (!ss->face_sets) {
+        return SCULPT_FACE_SET_NONE;
+      }
       const CCGKey *key = BKE_pbvh_get_grid_key(ss->pbvh);
       const int grid_index = vertex.i / key->grid_area;
       const int face_index = BKE_subdiv_ccg_grid_to_face_index(ss->subdiv_ccg, grid_index);
@@ -542,6 +569,9 @@ bool SCULPT_vertex_has_face_set(SculptSession *ss, PBVHVertRef vertex, int face_
 {
   switch (BKE_pbvh_type(ss->pbvh)) {
     case PBVH_FACES: {
+      if (!ss->face_sets) {
+        return face_set == SCULPT_FACE_SET_NONE;
+      }
       MeshElemMap *vert_map = &ss->pmap[vertex.i];
       for (int i = 0; i < ss->pmap[vertex.i].count; i++) {
         if (ss->face_sets[vert_map->indices[i]] == face_set) {
@@ -553,6 +583,9 @@ bool SCULPT_vertex_has_face_set(SculptSession *ss, PBVHVertRef vertex, int face_
     case PBVH_BMESH:
       return true;
     case PBVH_GRIDS: {
+      if (!ss->face_sets) {
+        return face_set == SCULPT_FACE_SET_NONE;
+      }
       const CCGKey *key = BKE_pbvh_get_grid_key(ss->pbvh);
       const int grid_index = vertex.i / key->grid_area;
       const int face_index = BKE_subdiv_ccg_grid_to_face_index(ss->subdiv_ccg, grid_index);
@@ -599,6 +632,9 @@ static void UNUSED_FUNCTION(sculpt_visibility_sync_vertex_to_face_sets)(SculptSe
 void SCULPT_visibility_sync_all_vertex_to_face_sets(SculptSession *ss)
 {
   if (BKE_pbvh_type(ss->pbvh) == PBVH_FACES) {
+    if (ss->face_sets == NULL) {
+      return;
+    }
     for (int i = 0; i < ss->totfaces; i++) {
       const MPoly *poly = &ss->mpoly[i];
       bool poly_visible = true;
@@ -620,6 +656,9 @@ void SCULPT_visibility_sync_all_vertex_to_face_sets(SculptSession *ss)
 
 static bool sculpt_check_unique_face_set_in_base_mesh(SculptSession *ss, int index)
 {
+  if (!ss->face_sets) {
+    return true;
+  }
   MeshElemMap *vert_map = &ss->pmap[index];
   int face_set = -1;
   for (int i = 0; i < ss->pmap[index].count; i++) {
@@ -676,6 +715,9 @@ bool SCULPT_vertex_has_unique_face_set(SculptSession *ss, PBVHVertRef vertex)
     case PBVH_BMESH:
       return true;
     case PBVH_GRIDS: {
+      if (!ss->face_sets) {
+        return true;
+      }
       const CCGKey *key = BKE_pbvh_get_grid_key(ss->pbvh);
       const int grid_index = vertex.i / key->grid_area;
       const int vertex_index = vertex.i - grid_index * key->grid_area;
@@ -703,6 +745,9 @@ int SCULPT_face_set_next_available_get(SculptSession *ss)
   switch (BKE_pbvh_type(ss->pbvh)) {
     case PBVH_FACES:
     case PBVH_GRIDS: {
+      if (!ss->face_sets) {
+        return 0;
+      }
       int next_face_set = 0;
       for (int i = 0; i < ss->totfaces; i++) {
         if (abs(ss->face_sets[i]) > next_face_set) {
@@ -792,9 +837,10 @@ static void sculpt_vertex_neighbors_get_faces(SculptSession *ss,
   iter->capacity = SCULPT_VERTEX_NEIGHBOR_FIXED_CAPACITY;
   iter->neighbors = iter->neighbors_fixed;
   iter->neighbor_indices = iter->neighbor_indices_fixed;
+  const bool *hide_poly = BKE_pbvh_get_vert_hide(ss->pbvh);
 
   for (int i = 0; i < ss->pmap[vertex.i].count; i++) {
-    if (ss->face_sets[vert_map->indices[i]] < 0) {
+    if (hide_poly && hide_poly[vert_map->indices[i]]) {
       /* Skip connectivity from hidden faces. */
       continue;
     }
@@ -3297,6 +3343,15 @@ static void do_brush_action(Sculpt *sd,
     BKE_pbvh_ensure_node_loops(ss->pbvh);
   }
 
+  if (SCULPT_tool_is_mask(brush->sculpt_tool)) {
+    MultiresModifierData *mmd = BKE_sculpt_multires_active(ss->scene, ob);
+    BKE_sculpt_mask_layers_ensure(ob, mmd);
+  }
+  if (SCULPT_tool_is_face_sets(brush->sculpt_tool)) {
+    Mesh *mesh = BKE_object_get_original_mesh(ob);
+    ss->face_sets = BKE_sculpt_face_sets_ensure(mesh);
+  }
+
   /* Build a list of all nodes that are potentially within the brush's area of influence */
 
   if (SCULPT_tool_needs_all_pbvh_nodes(brush)) {
diff --git a/source/blender/editors/sculpt_paint/sculpt_dyntopo.c b/source/blender/editors/sculpt_paint/sculpt_dyntopo.c
index 8b7b26b127d..2f5a1baa866 100644
--- a/source/blender/editors/sculpt_paint/sculpt_dyntopo.c
+++ b/source/blender/editors/sculpt_paint/sculpt_dyntopo.c
@@ -215,13 +215,7 @@ static void SCULPT_dynamic_topology_disable_ex(
     BKE_sculptsession_bm_to_me(ob, true);
 
     /* Reset Face Sets as they are no longer valid. */
-    if (!CustomData_has_layer(&me->pdata, CD_SCULPT_FACE_SETS)) {
-      CustomData_add_layer(&me->pdata, CD_SCULPT_FACE_SETS, CD_SET_DEFAULT, NULL, me->totpoly);
-    }
-    ss->face_sets = CustomData_get_layer(&me->pdata, CD_SCULPT_FACE_SETS);
-    for (int i = 0; i < me->totpoly; i++) {
-      ss->face_sets[i] = 1;
-    }
+    CustomData_free_layers(&me->pdata, CD_SCULPT_FACE_SETS, me->totpoly);
     me->face_sets_color_default = 1;
 
     /* Sync the visibility to vertices manually as the pmap is still not initialized. */
diff --git a/source/blender/editors/sculpt_paint/sculpt_expand.c b/source/blender/editors/sculpt_paint/sculpt_expand.c
index 4aafeacfbff..414a855ab2f 100644
--- a/source/blender/editors/sculpt_paint/sculpt_expand.c
+++ b/source/blender/editors/sculpt_paint/sculpt_expand.c
@@ -17,6 +17,7 @@
 #include "DNA_brush_types.h"
 #include "DNA_mesh_types.h"
 #include "DNA_meshdata_types.h"
+#include "DNA_modifier_types.h"
 #include "DNA_object_types.h"
 
 #include "BKE_brush.h"
@@ -1390,9 +1391,15 @@ static void sculpt_expand_original_state_store(Object *ob, ExpandCache *expand_c
   /* Face Sets are always stored as they are needed for snapping. */
   expand_cache->initial_face_sets = MEM_malloc_arrayN(totface, sizeof(int), "initial face set");
   expand_cache->original_face_sets = MEM_malloc_arrayN(totface, sizeof(int), "original face set");
-  for (int i = 0; i < totface; i++) {
-    expand_cache->initial_face_sets[i] = ss->face_sets[i];
-    expand_cache->original_face_sets[i] = ss->face_sets[i];
+  if (ss->face_sets) {
+    for (int i = 0; i < totface; i++) {
+      expand_cache->initial_face_sets[i] = ss->face_sets[i];
+      expand_cache->original_face_sets[i] = ss->face_sets[i];
+    }
+  }
+  else {
+    memset(expand_cache->initial_face_sets, SCULPT_FACE_SET_NONE, sizeof(int) * totface);
+    memset(expand_cache->original_face_sets, SCULPT_FACE_SET_NONE, sizeof(int) * totface);
   }
 
   if (expand_cache->target == SCULPT_EXPAND_TARGET_MASK) {
@@ -2118,6 +2125,16 @@ static int sculpt_expand_invoke(bContext *C, wmOperator *op, const wmEvent *even
     return OPERATOR_CANCELLED;
   }
 
+  if (ss->expand_cache->target == SCULPT_EXPAND_TARGET_FACE_SETS) {
+    Mesh *mesh = ob->data;
+    ss->face_sets = BKE_sculpt_face_sets_ensure(mesh);
+  }
+
+  if (ss->expand_cache->target == SCULPT_EXPAND_TARGET_MASK) {
+    MultiresModifierData *mmd = BKE_sculpt_multires_active(ss->scene, ob);
+    BKE_sculpt_mask_layers_ensure(ob, mmd);
+  }
+
   /* Face Set operations are not supported in dyntopo. */
   if (ss->expand_cache->target == SCULPT_EXPAND_TARGET_FACE_SETS &&
       BKE_pbvh_type(ss->pbvh) == PBVH_BMESH) {
diff --git a/source/blender/editors/sculpt_paint/sculpt_face_set.c b/source/blender/editors/sculpt_paint/sculpt_face_set.c
index 3c724915102..d2030aa5505 100644
--- a/source/blender/editors/sculpt_paint/sculpt_face_set.c
+++ b/source/blender/editors/sculpt_paint/sculpt_face_set.c
@@ -303,6 +303,9 @@ static int sculpt_face_set_create_exec(bContext *C, wmOperator *op)
     return OPERATOR_CANCELLED;
   }
 
+  Mesh *mesh = ob->data;
+  ss->face_sets = BKE_sculpt_face_sets_ensure(mesh);
+
   BKE_sculpt_update_object_for_edit(depsgraph, ob, true, mode == SCULPT_FACE_SET_MASKED, false);
 
   const int tot_vert = SCULPT_vertex_count_get(ss);
@@ -349,7 +352,6 @@ static int sculpt_face_set_create_exec(bContext *C, wmOperator *op)
     }
 
     if (all_visible) {
-      Mesh *mesh = ob->data;
       mesh->face_sets_color_default = next_face_set;
       BKE_pbvh_face_sets_color_set(
           ss->pbvh, mesh->face_sets_color_seed, mesh->face_sets_color_default);
@@ -373,7 +375,6 @@ static int sculpt_face_set_create_exec(bContext *C, wmOperator *op)
   }
 
   if (mode == SCULPT_FACE_SET_SELECTION) {
-    Mesh *mesh = ob->data;
     BMesh *bm;
     const BMAllocTemplate allocsize = BMALLOC_TEMPLATE_FROM_ME(mesh);
     bm = BM_mesh_create(&allocsize,
@@ -850,6 +851,10 @@ static int sculpt_face_sets_change_visibility_exec(bContext *C, wmOperator *op)
     return OPERATOR_CANCELLED;
   }
 
+  if (!pbvh_has_face_sets(ss->pbvh)) {
+    return OPERATOR_CANCELLED;
+  }
+
   BKE_sculpt_update_object_for_edit(depsgraph, ob, true, true, false);
 
   const int tot_vert = SCULPT_vertex_count_get(ss);
@@ -1000,6 +1005,10 @@ static int sculpt_face_sets_randomize_colors_exec(bContext *C, wmOperator *UNUSE
     return OPERATOR_CANCELLED;
   }
 
+  if (!pbvh_has_face_sets(ss->pbvh)) {
+    return OPERATOR_CANCELLED;
+  }
+
   PBVH *pbvh = ob->sculpt->pbvh;
   PBVHNode **nodes;
   int totnode;
@@ -1154,7 +1163,9 @@ static void sculpt_face_set_shrink(Object *ob,
 
 static bool check_single_face_set(SculptSession *ss, int *face_sets, const bool check_visible_only)
 {
-
+  if (face_sets == NULL) {
+    return true;
+  }
   int first_face_set = SCULPT_FACE_SET_NONE;
   if (check_visible_only) {
     for (int f = 0; f < ss->totfaces; f++) {
diff --git a/source/blender/editors/sculpt_paint/sculpt_filter_mask.c b/source/blender/editors/sculpt_paint/sculpt_filter_mask.c
index cba1d3dcdc1..bb27e4f1e9e 100644
--- a/source/blender/editors/sculpt_paint/sculpt_filter_mask.c
+++ b/source/blender/editors/sculpt_paint/sculpt_filter_mask.c
@@ -14,6 +14,7 @@
 
 #include "DNA_mesh_types.h"
 #include "DNA_meshdata_types.h"
+#include "DNA_modifier_types.h"
 
 #include "BKE_brush.h"
 #include "BKE_context.h"
@@ -174,11 +175,15 @@ static int sculpt_mask_filter_exec(bContext *C, wmOperator *op)
 {
   Object *ob = CTX_data_active_object(C);
   Depsgraph *depsgraph = CTX_data_depsgraph_pointer(C);
+  const Scene *scene = CTX_data_scene(C);
   PBVHNode **nodes;
   Sculpt *sd = CTX_data_tool_settings(C)->sculpt;
   int totnode;
   int filter_type = RNA_enum_get(op->ptr, "filter_type");
 
+  MultiresModifierData *mmd = BKE_sculpt_multires_active(scene, ob);
+  BKE_sculpt_mask_layers_ensure(ob, mmd);
+
   BKE_sculpt_update_object_for_edit(depsgraph, ob, true, true, false);
 
   SculptSession *ss = ob->sculpt;
diff --git a/source/blender/editors/sculpt_paint/sculpt_geodesic.c b/source/blender/editors/sculpt_paint/sculpt_geodesic.c
index 7f6da27ddcf..6f813c9920e 100644
--- a/source/blender/editors/sculpt_paint/sculpt_geodesic.c
+++ b/source/blender/editors/sculpt_paint/sculpt_geodesic.c
@@ -174,6 +174,8 @@ static float *SCULPT_geodesic_mesh_create(Object *ob,
     }
   }
 
+  const bool *hide_poly = BKE_pbvh_get_poly_hide(ss->pbvh);
+
   /* Add edges adjacent to an initial vertex to the queue. */
   for (int i = 0; i < totedge; i++) {
     const int v1 = edges[i].v1;
@@ -203,7 +205,7 @@ static float *SCULPT_geodesic_mesh_create(Object *ob,
       if (ss->epmap[e].count != 0) {
         for (int poly_map_index = 0; poly_map_index < ss->epmap[e].count; poly_map_index++) {
           const int poly = ss->epmap[e].indices[poly_map_index];
-          if (ss->face_sets[poly] <= 0) {
+          if (hide_poly && hide_poly[poly]) {
             continue;
           }
           const MPoly *mpoly = &polys[poly];
diff --git a/source/blender/editors/sculpt_paint/sculpt_intern.h b/source/blender/editors/sculpt_paint/sculpt_intern.h
index cf901d7cf36..607e0fc3ef6 100644
--- a/source/blender/editors/sculpt_paint/sculpt_intern.h
+++ b/source/blender/editors/sculpt_paint/sculpt_intern.h
@@ -1837,6 +1837,16 @@ BLI_INLINE bool SCULPT_tool_is_paint(int tool)
   return ELEM(tool, SCULPT_TOOL_PAINT, SCULPT_TOOL_SMEAR);
 }
 
+BLI_INLINE bool SCULPT_tool_is_mask(int tool)
+{
+  return ELEM(tool, SCULPT_TOOL_MASK);
+}
+
+BLI_INLINE bool SCULPT_tool_is_face_sets(int tool)
+{
+  return ELEM(tool, SCULPT_TOOL_DRAW_FACE_SETS);
+}
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/blender/editors/sculpt_paint/sculpt_mask_expand.c b/source/blender/editors/sculpt_paint/sculpt_mask_expand.c
index 9556d24f12c..ec246cd3788 100644
--- a/source/blender/editors/sculpt_paint/sculpt_mask_expand.c
+++ b/source/blender/editors/sculpt_paint/sculpt_mask_expand.c
@@ -391,7 +391,7 @@ static int sculpt_mask_expand_invoke(bContext *C, wmOperator *op, const wmEvent
   if (create_face_set) {
     ss->filter_cache->prev_face_set = MEM_callocN(sizeof(float) * ss->totfaces, "prev face mask");
     for (int i = 0; i < ss->totfaces; i++) {
-      ss->filter_cache->prev_face_set[i] = ss->face_sets[i];
+      ss->filter_cache->prev_face_set[i] = ss->face_sets ? ss->face_sets[i] : 0;
     }
     ss->filter_cache->new_face_set = SCULPT_face_set_next_available_get(ss);
   }
diff --git a/source/blender/editors/sculpt_paint/sculpt_ops.c b/source/blender/editors/sculpt_paint/sculpt_ops.c
index 10a2ece73de..055e02a5703 100644
--- a/source/blender/editors/sculpt_paint/sculpt_ops.c
+++ b/source/blender/editors/sculpt_paint/sculpt_ops.c
@@ -300,28 +300,30 @@ static void sculpt_init_session(Main *bmain, Depsgraph *depsgraph, Scene *scene,
   ob->sculpt = MEM_callocN(sizeof(SculptSession), "sculpt session");
   ob->sculpt->mode_type = OB_MODE_SCULPT;
 
-  BKE_sculpt_ensure_orig_mesh_data(scene, ob);
+  BKE_sculpt_ensure_orig_mesh_data(ob);
 
   BKE_scene_graph_evaluated_ensure(depsgraph, bmain);
 
   /* This function expects a fully evaluated depsgraph. */
   BKE_sculpt_update_object_for_edit(depsgraph, ob, false, false, false);
 
-  /* Here we can detect geometry that was just added to Sculpt Mode as it has the
-   * SCULPT_FACE_SET_NONE assigned, so we can create a new Face Set for it. */
-  /* In sculpt mode all geometry that is assigned to SCULPT_FACE_SET_NONE is considered as not
-   * initialized, which is used is some operators that modify the mesh topology to perform certain
-   * actions in the new polys. After these operations are finished, all polys should have a valid
-   * face set ID assigned (different from SCULPT_FACE_SET_NONE) to manage their visibility
-   * correctly. */
-  /* TODO(pablodp606): Based on this we can improve the UX in future tools for creating new
-   * objects, like moving the transform pivot position to the new area or masking existing
-   * geometry. */
   SculptSession *ss = ob->sculpt;
-  const int new_face_set = SCULPT_face_set_next_available_get(ss);
-  for (int i = 0; i < ss->totfaces; i++) {
-    if (ss->face_sets[i] == SCULPT_FACE_SET_NONE) {
-      ss->face_sets[i] = new_face_set;
+  if (ss->face_sets) {
+    /* Here we can detect geometry that was just added to Sculpt Mode as it has the
+     * SCULPT_FACE_SET_NONE assigned, so we can create a new Face Set for it. */
+    /* In sculpt mode all geometry that is assigned to SCULPT_FACE_SET_NONE is considered as not
+     * initialized, which is used is some operators that modify the mesh topology to perform
+     * certain actions in the new polys. After these operations are finished, all polys should have
+     * a valid face set ID assigned (different from SCULPT_FACE_SET_NONE) to manage their
+     * visibility correctly. */
+    /* TODO(pablodp606): Based on this we can improve the UX in future tools for creating new
+     * objects, like moving the transform pivot position to the new area or masking existing
+     * geometry. */
+    const int new_face_set = SCULPT_face_set_next_available_get(ss);
+    for (int i = 0; i < ss->totfaces; i++) {
+      if (ss->face_sets[i] == SCULPT_FACE_SET_NONE) {
+        ss->face_sets[i] = new_face_set;
+      }
     }
   }
 }
diff --git a/source/blender/editors/sculpt_paint/sculpt_undo.c b/source/blender/editors/sculpt_paint/sculpt_undo.c
index fb8e2ae91b6..54ae6d84df7 100644
--- a/source/blender/editors/sculpt_paint/sculpt_undo.c
+++ b/source/blender/editors/sculpt_paint/sculpt_undo.c
@@ -474,9 +474,10 @@ static bool sculpt_undo_restore_face_sets(bContext *C, SculptUndoNode *unode)
   ViewLayer *view_layer = CTX_data_view_layer(C);
   Object *ob = BKE_view_layer_active_object_get(view_layer);
   Mesh *me = BKE_object_get_original_mesh(ob);
-  int *face_sets = CustomData_get_layer(&me->pdata, CD_SCULPT_FACE_SETS);
+  int *face_sets = CustomData_add_layer(
+      &me->pdata, CD_SCULPT_FACE_SETS, CD_CONSTRUCT, NULL, me->totpoly);
   for (int i = 0; i < me->totpoly; i++) {
-    face_sets[i] = unode->face_sets[i];
+    SWAP(int, face_sets[i], unode->face_sets[i]);
   }
   return false;
 }
@@ -1350,8 +1351,13 @@ static SculptUndoNode *sculpt_undo_face_sets_push(Object *ob, SculptUndoType typ
   unode->face_sets = MEM_callocN(me->totpoly * sizeof(int), "sculpt face sets");
 
   const int *face_sets = CustomData_get_layer(&me->pdata, CD_SCULPT_FACE_SETS);
-  for (int i = 0; i < me->totpoly; i++) {
-    unode->face_sets[i] = face_sets[i];
+  if (face_sets) {
+    for (int i = 0; i < me->totpoly; i++) {
+      unode->face_sets[i] = face_sets[i];
+    }
+  }
+  else {
+    memset(unode->face_sets, SCULPT_FACE_SET_NONE, sizeof(int) * me->totpoly);
   }
 
   BLI_addtail(&usculpt->nodes, unode);
@@ -1509,7 +1515,9 @@ SculptUndoNode *SCULPT_undo_push_node(Object *ob, PBVHNode *node, SculptUndoType
       sculpt_undo_store_hidden(ob, unode);
       break;
     case SCULPT_UNDO_MASK:
-      sculpt_undo_store_mask(ob, unode);
+      if (pbvh_has_mask(ss->pbvh)) {
+        sculpt_undo_store_mask(ob, unode);
+      }
       break;
     case SCULPT_UNDO_COLOR:
       sculpt_undo_store_color(ob, unode);
diff --git a/source/blender/editors/sculpt_paint/sculpt_uv.c b/source/blender/editors/sculpt_paint/sculpt_uv.c
index 8b9776cf94d..4739fa52674 100644
--- a/source/blender/editors/sculpt_paint/sculpt_uv.c
+++ b/source/blender/editors/sculpt_paint/sculpt_uv.c
@@ -686,9 +686,10 @@ static UvSculptData *uv_sculpt_stroke_init(bContext *C, wmOperator *op, const wm
     /* Winding was added to island detection in 5197aa04c6bd
      * However the sculpt tools can flip faces, potentially creating orphaned islands.
      * See T100132 */
-    bool use_winding = false;
+    const bool use_winding = false;
+    const bool use_seams = true;
     data->elementMap = BM_uv_element_map_create(
-        bm, scene, false, use_winding, do_island_optimization);
+        bm, scene, false, use_winding, use_seams, do_island_optimization);
 
     if (!data->elementMap) {
       uv_sculpt_stroke_exit(C, op);
diff --git a/source/blender/editors/space_image/image_undo.cc b/source/blender/editors/space_image/image_undo.cc
index 065641c4051..8f144264824 100644
--- a/source/blender/editors/space_image/image_undo.cc
+++ b/source/blender/editors/space_image/image_undo.cc
@@ -522,7 +522,7 @@ static void ubuf_ensure_compat_ibuf(const UndoImageBuf *ubuf, ImBuf *ibuf)
   IMB_rect_size_set(ibuf, ubuf->image_dims);
 
   if (ubuf->image_state.use_float) {
-    imb_addrectfloatImBuf(ibuf);
+    imb_addrectfloatImBuf(ibuf, 4);
   }
   else {
     imb_addrectImBuf(ibuf);
diff --git a/source/blender/editors/space_nla/nla_edit.c b/source/blender/editors/space_nla/nla_edit.c
index 801d032a861..bcdbbb00d1c 100644
--- a/source/blender/editors/space_nla/nla_edit.c
+++ b/source/blender/editors/space_nla/nla_edit.c
@@ -606,6 +606,36 @@ void NLA_OT_view_frame(wmOperatorType *ot)
  * (or the active block if no space in the track).
  * \{ */
 
+/* Get a list of the editable tracks being shown in the NLA. */
+static int nlaedit_get_editable_tracks(bAnimContext *ac, ListBase *anim_data)
+{
+  const int filter = (ANIMFILTER_DATA_VISIBLE | ANIMFILTER_ACTIVE | ANIMFILTER_FOREDIT |
+            ANIMFILTER_FCURVESONLY);
+  return ANIM_animdata_filter(ac, anim_data, filter, ac->data, ac->datatype);
+}
+
+static int nlaedit_add_actionclip_invoke(bContext *C, wmOperator *op, const wmEvent *event)
+{
+  /* Get editor data. */
+  bAnimContext ac;
+  if (ANIM_animdata_get_context(C, &ac) == 0) {
+    return OPERATOR_CANCELLED;
+  }
+
+  ListBase anim_data = {NULL, NULL};
+  const size_t items = nlaedit_get_editable_tracks(&ac, &anim_data);
+
+  if (items == 0) {
+    BKE_report(op->reports,
+               RPT_ERROR,
+               "No active track(s) to add strip to, select an existing track or add one before "
+               "trying again");
+    return OPERATOR_CANCELLED;
+  }
+
+  return WM_enum_search_invoke(C, op, event);
+}
+
 /* add the specified action as new strip */
 static int nlaedit_add_actionclip_exec(bContext *C, wmOperator *op)
 {
@@ -615,8 +645,6 @@ static int nlaedit_add_actionclip_exec(bContext *C, wmOperator *op)
 
   ListBase anim_data = {NULL, NULL};
   bAnimListElem *ale;
-  size_t items;
-  int filter;
 
   bAction *act;
 
@@ -654,20 +682,7 @@ static int nlaedit_add_actionclip_exec(bContext *C, wmOperator *op)
    */
   nlaedit_add_tracks_empty(&ac);
 
-  /* get a list of the editable tracks being shown in the NLA
-   * - this is limited to active ones for now, but could be expanded to
-   */
-  filter = (ANIMFILTER_DATA_VISIBLE | ANIMFILTER_ACTIVE | ANIMFILTER_FOREDIT |
-            ANIMFILTER_FCURVESONLY);
-  items = ANIM_animdata_filter(&ac, &anim_data, filter, ac.data, ac.datatype);
-
-  if (items == 0) {
-    BKE_report(op->reports,
-               RPT_ERROR,
-               "No active track(s) to add strip to, select an existing track or add one before "
-               "trying again");
-    return OPERATOR_CANCELLED;
-  }
+  nlaedit_get_editable_tracks(&ac, &anim_data);
 
   /* for every active track,
    * try to add strip to free space in track or to the top of the stack if no space */
@@ -736,7 +751,7 @@ void NLA_OT_actionclip_add(wmOperatorType *ot)
       "Add an Action-Clip strip (i.e. an NLA Strip referencing an Action) to the active track";
 
   /* api callbacks */
-  ot->invoke = WM_enum_search_invoke;
+  ot->invoke = nlaedit_add_actionclip_invoke;
   ot->exec = nlaedit_add_actionclip_exec;
   ot->poll = nlaop_poll_tweakmode_off;
 
diff --git a/source/blender/editors/space_node/link_drag_search.cc b/source/blender/editors/space_node/link_drag_search.cc
index a4be0a65230..f1387da97b5 100644
--- a/source/blender/editors/space_node/link_drag_search.cc
+++ b/source/blender/editors/space_node/link_drag_search.cc
@@ -227,12 +227,10 @@ static void link_drag_search_exec_fn(bContext *C, void *arg1, void *arg2)
   ED_node_tree_propagate_change(C, &bmain, snode.edittree);
 
   /* Start translation operator with the new node. */
-  wmOperatorType *ot = WM_operatortype_find("NODE_OT_translate_attach", true);
+  wmOperatorType *ot = WM_operatortype_find("NODE_OT_translate_attach_remove_on_cancel", true);
   BLI_assert(ot);
   PointerRNA ptr;
   WM_operator_properties_create_ptr(&ptr, ot);
-  RNA_boolean_set(&ptr, "view2d_edge_pan", true);
-  RNA_boolean_set(&ptr, "remove_on_cancel", true);
   WM_operator_name_call_ptr(C, ot, WM_OP_INVOKE_DEFAULT, &ptr, nullptr);
   WM_operator_properties_free(&ptr);
 }
diff --git a/source/blender/editors/space_node/node_ops.cc b/source/blender/editors/space_node/node_ops.cc
index 3b3189983e2..a208370a6f9 100644
--- a/source/blender/editors/space_node/node_ops.cc
+++ b/source/blender/editors/space_node/node_ops.cc
@@ -144,7 +144,7 @@ void ED_operatormacros_node()
   WM_operatortype_macro_define(ot, "NODE_OT_attach");
   WM_operatortype_macro_define(ot, "NODE_OT_insert_offset");
 
-  /* NODE_OT_translate_attach with remove_on_canel set to true */
+  /* NODE_OT_translate_attach with remove_on_cancel set to true. */
   ot = WM_operatortype_append_macro("NODE_OT_translate_attach_remove_on_cancel",
                                     "Move and Attach",
                                     "Move nodes and attach to frame",
diff --git a/source/blender/editors/space_node/node_relationships.cc b/source/blender/editors/space_node/node_relationships.cc
index 7dbaa8ccd6d..929fb64bd70 100644
--- a/source/blender/editors/space_node/node_relationships.cc
+++ b/source/blender/editors/space_node/node_relationships.cc
@@ -1727,32 +1727,34 @@ static int node_attach_invoke(bContext *C, wmOperator *UNUSED(op), const wmEvent
   SpaceNode &snode = *CTX_wm_space_node(C);
   bNodeTree &ntree = *snode.edittree;
   bNode *frame = node_find_frame_to_attach(region, ntree, event->mval);
+  if (frame == nullptr) {
+    /* Return "finished" so that auto offset operator macros can work. */
+    return OPERATOR_FINISHED;
+  }
 
-  if (frame) {
-    LISTBASE_FOREACH_BACKWARD (bNode *, node, &ntree.nodes) {
-      if (node->flag & NODE_SELECT) {
-        if (node->parent == nullptr) {
-          /* disallow moving a parent into its child */
-          if (nodeAttachNodeCheck(frame, node) == false) {
-            /* attach all unparented nodes */
-            nodeAttachNode(node, frame);
-          }
+  LISTBASE_FOREACH_BACKWARD (bNode *, node, &ntree.nodes) {
+    if (node->flag & NODE_SELECT) {
+      if (node->parent == nullptr) {
+        /* disallow moving a parent into its child */
+        if (nodeAttachNodeCheck(frame, node) == false) {
+          /* attach all unparented nodes */
+          nodeAttachNode(node, frame);
         }
-        else {
-          /* attach nodes which share parent with the frame */
-          bNode *parent;
-          for (parent = frame->parent; parent; parent = parent->parent) {
-            if (parent == node->parent) {
-              break;
-            }
+      }
+      else {
+        /* attach nodes which share parent with the frame */
+        bNode *parent;
+        for (parent = frame->parent; parent; parent = parent->parent) {
+          if (parent == node->parent) {
+            break;
           }
+        }
 
-          if (parent) {
-            /* disallow moving a parent into its child */
-            if (nodeAttachNodeCheck(frame, node) == false) {
-              nodeDetachNode(node);
-              nodeAttachNode(node, frame);
-            }
+        if (parent) {
+          /* disallow moving a parent into its child */
+          if (nodeAttachNodeCheck(frame, node) == false) {
+            nodeDetachNode(node);
+            nodeAttachNode(node, frame);
           }
         }
       }
diff --git a/source/blender/editors/space_node/node_select.cc b/source/blender/editors/space_node/node_select.cc
index 1f1ce9c0c2b..d93b205b1b7 100644
--- a/source/blender/editors/space_node/node_select.cc
+++ b/source/blender/editors/space_node/node_select.cc
@@ -644,28 +644,29 @@ static bool node_mouse_select(bContext *C,
     }
   }
 
-  /* update node order */
-  if (changed || found) {
-    bool active_texture_changed = false;
-    bool viewer_node_changed = false;
-    if ((node != nullptr) && (node_was_selected == false || params->select_passthrough == false)) {
-      viewer_node_changed = (node->flag & NODE_DO_OUTPUT) == 0 && node->type == GEO_NODE_VIEWER;
-      ED_node_set_active(&bmain, &snode, snode.edittree, node, &active_texture_changed);
-    }
-    else if (node != nullptr && node->type == GEO_NODE_VIEWER) {
-      ED_spreadsheet_context_paths_set_geometry_node(&bmain, &snode, node);
-    }
-    ED_node_set_active_viewer_key(&snode);
-    node_sort(*snode.edittree);
-    if ((active_texture_changed && has_workbench_in_texture_color(wm, scene, ob)) ||
-        viewer_node_changed) {
-      DEG_id_tag_update(&snode.edittree->id, ID_RECALC_COPY_ON_WRITE);
-    }
+  if (!(changed || found)) {
+    return false;
+  }
 
-    WM_event_add_notifier(C, NC_NODE | NA_SELECTED, nullptr);
+  bool active_texture_changed = false;
+  bool viewer_node_changed = false;
+  if ((node != nullptr) && (node_was_selected == false || params->select_passthrough == false)) {
+    viewer_node_changed = (node->flag & NODE_DO_OUTPUT) == 0 && node->type == GEO_NODE_VIEWER;
+    ED_node_set_active(&bmain, &snode, snode.edittree, node, &active_texture_changed);
   }
+  else if (node != nullptr && node->type == GEO_NODE_VIEWER) {
+    ED_spreadsheet_context_paths_set_geometry_node(&bmain, &snode, node);
+  }
+  ED_node_set_active_viewer_key(&snode);
+  node_sort(*snode.edittree);
+  if ((active_texture_changed && has_workbench_in_texture_color(wm, scene, ob)) ||
+      viewer_node_changed) {
+    DEG_id_tag_update(&snode.edittree->id, ID_RECALC_COPY_ON_WRITE);
+  }
+
+  WM_event_add_notifier(C, NC_NODE | NA_SELECTED, nullptr);
 
-  return changed || found;
+  return true;
 }
 
 static int node_select_exec(bContext *C, wmOperator *op)
diff --git a/source/blender/editors/transform/transform_convert_action.c b/source/blender/editors/transform/transform_convert_action.c
index 252f150995e..83e47d9acc0 100644
--- a/source/blender/editors/transform/transform_convert_action.c
+++ b/source/blender/editors/transform/transform_convert_action.c
@@ -902,18 +902,18 @@ static void special_aftertrans_update__actedit(bContext *C, TransInfo *t)
         if (ELEM(t->frame_side, 'L', 'R')) { /* TFM_TIME_EXTEND */
           /* same as below */
           ED_markers_post_apply_transform(
-              ED_context_get_markers(C), t->scene, t->mode, t->values[0], t->frame_side);
+              ED_context_get_markers(C), t->scene, t->mode, t->values_final[0], t->frame_side);
         }
         else /* TFM_TIME_TRANSLATE */
 #endif
       {
         ED_markers_post_apply_transform(
-            ED_context_get_markers(C), t->scene, t->mode, t->values[0], t->frame_side);
+            ED_context_get_markers(C), t->scene, t->mode, t->values_final[0], t->frame_side);
       }
     }
     else if (t->mode == TFM_TIME_SCALE) {
       ED_markers_post_apply_transform(
-          ED_context_get_markers(C), t->scene, t->mode, t->values[0], t->frame_side);
+          ED_context_get_markers(C), t->scene, t->mode, t->values_final[0], t->frame_side);
     }
   }
 
diff --git a/source/blender/editors/transform/transform_convert_mesh_uv.c b/source/blender/editors/transform/transform_convert_mesh_uv.c
index f3bef2c283b..27f12137e3a 100644
--- a/source/blender/editors/transform/transform_convert_mesh_uv.c
+++ b/source/blender/editors/transform/transform_convert_mesh_uv.c
@@ -265,7 +265,7 @@ static void createTransUVs(bContext *C, TransInfo *t)
     /* count */
     if (is_island_center) {
       /* create element map with island information */
-      elementmap = BM_uv_element_map_create(em->bm, scene, true, false, true);
+      elementmap = BM_uv_element_map_create(em->bm, scene, true, false, true, true);
       if (elementmap == NULL) {
         continue;
       }
diff --git a/source/blender/editors/transform/transform_convert_sequencer.c b/source/blender/editors/transform/transform_convert_sequencer.c
index eefc9d0cc2a..ddc99caeef5 100644
--- a/source/blender/editors/transform/transform_convert_sequencer.c
+++ b/source/blender/editors/transform/transform_convert_sequencer.c
@@ -708,12 +708,12 @@ static void special_aftertrans_update__sequencer(bContext *UNUSED(C), TransInfo
     if (t->mode == TFM_SEQ_SLIDE) {
       if (t->frame_side == 'B') {
         ED_markers_post_apply_transform(
-            &t->scene->markers, t->scene, TFM_TIME_TRANSLATE, t->values[0], t->frame_side);
+            &t->scene->markers, t->scene, TFM_TIME_TRANSLATE, t->values_final[0], t->frame_side);
       }
     }
     else if (ELEM(t->frame_side, 'L', 'R')) {
       ED_markers_post_apply_transform(
-          &t->scene->markers, t->scene, TFM_TIME_EXTEND, t->values[0], t->frame_side);
+          &t->scene->markers, t->scene, TFM_TIME_EXTEND, t->values_final[0], t->frame_side);
     }
   }
 }
diff --git a/source/blender/editors/util/ed_util.c b/source/blender/editors/util/ed_util.c
index 2f268d4ae23..e70851aedd6 100644
--- a/source/blender/editors/util/ed_util.c
+++ b/source/blender/editors/util/ed_util.c
@@ -377,7 +377,7 @@ void unpack_menu(bContext *C,
     char local_name[FILE_MAXDIR + FILE_MAX], fi[FILE_MAX];
 
     BLI_split_file_part(abs_name, fi, sizeof(fi));
-    BLI_snprintf(local_name, sizeof(local_name), "//%s/%s", folder, fi);
+    BLI_path_join(local_name, sizeof(local_name), "//", folder, fi, NULL);
     if (!STREQ(abs_name, local_name)) {
       switch (BKE_packedfile_compare_to_file(blendfile_path, local_name, pf)) {
         case PF_CMP_NOFILE:
diff --git a/source/blender/editors/uvedit/uvedit_ops.c b/source/blender/editors/uvedit/uvedit_ops.c
index c0dd7623ade..4cc2c6450df 100644
--- a/source/blender/editors/uvedit/uvedit_ops.c
+++ b/source/blender/editors/uvedit/uvedit_ops.c
@@ -535,7 +535,7 @@ static bool uvedit_uv_straighten(Scene *scene, BMesh *bm, eUVWeldAlign tool)
     return false;
   }
 
-  UvElementMap *element_map = BM_uv_element_map_create(bm, scene, true, false, true);
+  UvElementMap *element_map = BM_uv_element_map_create(bm, scene, true, false, true, true);
   if (element_map == NULL) {
     return false;
   }
diff --git a/source/blender/editors/uvedit/uvedit_select.c b/source/blender/editors/uvedit/uvedit_select.c
index cecf0ff7914..43c8620df1d 100644
--- a/source/blender/editors/uvedit/uvedit_select.c
+++ b/source/blender/editors/uvedit/uvedit_select.c
@@ -5384,7 +5384,7 @@ static void uv_isolate_selected_islands(const Scene *scene,
   BLI_assert((scene->toolsettings->uv_flag & UV_SYNC_SELECTION) == 0);
   BMFace *efa;
   BMIter iter, liter;
-  UvElementMap *elementmap = BM_uv_element_map_create(em->bm, scene, false, false, true);
+  UvElementMap *elementmap = BM_uv_element_map_create(em->bm, scene, false, false, true, true);
   if (elementmap == NULL) {
     return;
   }
diff --git a/source/blender/editors/uvedit/uvedit_smart_stitch.c b/source/blender/editors/uvedit/uvedit_smart_stitch.c
index e89f99fc412..e19cc67bd16 100644
--- a/source/blender/editors/uvedit/uvedit_smart_stitch.c
+++ b/source/blender/editors/uvedit/uvedit_smart_stitch.c
@@ -1855,7 +1855,7 @@ static StitchState *stitch_init(bContext *C,
    * for stitch this isn't useful behavior, see T86924. */
   const int selectmode_orig = scene->toolsettings->selectmode;
   scene->toolsettings->selectmode = SCE_SELECT_VERTEX;
-  state->element_map = BM_uv_element_map_create(state->em->bm, scene, false, true, true);
+  state->element_map = BM_uv_element_map_create(state->em->bm, scene, false, true, true, true);
   scene->toolsettings->selectmode = selectmode_orig;
 
   if (!state->element_map) {
diff --git a/source/blender/geometry/intern/add_curves_on_mesh.cc b/source/blender/geometry/intern/add_curves_on_mesh.cc
index 5173eaa3f1b..047f7dc7911 100644
--- a/source/blender/geometry/intern/add_curves_on_mesh.cc
+++ b/source/blender/geometry/intern/add_curves_on_mesh.cc
@@ -372,6 +372,28 @@ AddCurvesOnMeshOutputs add_curves_on_mesh(CurvesGeometry &curves,
 
   curves.fill_curve_types(new_curves_range, CURVE_TYPE_CATMULL_ROM);
 
+  /* Explicitly set all other attributes besides those processed above to default values. */
+  bke::MutableAttributeAccessor attributes = curves.attributes_for_write();
+  Set<std::string> attributes_to_skip{{"position",
+                                       "curve_type",
+                                       "surface_uv_coordinate",
+                                       ".selection_point_float",
+                                       ".selection_curve_float"}};
+  attributes.for_all(
+      [&](const bke::AttributeIDRef &id, const bke::AttributeMetaData /*meta_data*/) {
+        if (id.is_named() && attributes_to_skip.contains(id.name())) {
+          return true;
+        }
+        bke::GSpanAttributeWriter attribute = attributes.lookup_for_write_span(id);
+        const int new_elements_num = attribute.domain == ATTR_DOMAIN_POINT ? new_points_num :
+                                                                             new_curves_num;
+        const CPPType &type = attribute.span.type();
+        GMutableSpan new_data = attribute.span.take_back(new_elements_num);
+        type.fill_assign_n(type.default_value(), new_data.data(), new_data.size());
+        attribute.finish();
+        return true;
+      });
+
   return outputs;
 }
 
diff --git a/source/blender/geometry/intern/uv_parametrizer.cc b/source/blender/geometry/intern/uv_parametrizer.cc
index 4f763b09bef..f074febe23a 100644
--- a/source/blender/geometry/intern/uv_parametrizer.cc
+++ b/source/blender/geometry/intern/uv_parametrizer.cc
@@ -307,12 +307,70 @@ static float p_vec2_angle(const float v1[2], const float v2[2], const float v3[2
 {
   return angle_v2v2v2(v1, v2, v3);
 }
+
+/* Angles close to 0 or 180 degrees cause rows filled with zeros in the linear_solver.
+ * The matrix will then be rank deficient and / or have poor conditioning.
+ * => Reduce the maximum angle to 179 degrees, and spread the remainder to the other angles.
+ */
+static void fix_large_angle(const float v_fix[3],
+                            const float v1[3],
+                            const float v2[3],
+                            float *r_fix,
+                            float *r_a1,
+                            float *r_a2)
+{
+  const float max_angle = (float)M_PI * (179.0f / 180.0f);
+  const float fix_amount = *r_fix - max_angle;
+  if (fix_amount < 0.0f) {
+    return; /* angle is reasonable, i.e. less than 179 degrees. */
+  }
+
+  /* The triangle is probably degenerate, or close to it.
+   * Without loss of generality, transform the triangle such that
+   *   v_fix == {  0, s}, *r_fix = 180 degrees
+   *   v1    == {-x1, 0}, *r_a1  = 0
+   *   v2    == { x2, 0}, *r_a2  = 0
+   *
+   * With `s = 0`, `x1 > 0`, `x2 > 0`
+   *
+   * Now make `s` a small number and do some math:
+   *  tan(*r_a1) = s / x1
+   *  tan(*r_a2) = s / x2
+   *
+   * Remember that `tan = sin / cos`, `sin(s) ~= s` and `cos(s) = 1`
+   *
+   * Rearrange to obtain:
+   *  *r_a1 = fix_amount * x2 / (x1 + x2)
+   *  *r_a2 = fix_amount * x1 / (x1 + x2)
+   */
+
+  const float dist_v1 = len_v3v3(v_fix, v1);
+  const float dist_v2 = len_v3v3(v_fix, v2);
+  const float sum = dist_v1 + dist_v2;
+  const float weight = (sum > 1e-20f) ? dist_v2 / sum : 0.5f;
+
+  /* Ensure sum of angles in triangle is unchanged. */
+  *r_fix -= fix_amount;
+  *r_a1 += fix_amount * weight;
+  *r_a2 += fix_amount * (1.0f - weight);
+}
+
 static void p_triangle_angles(
     const float v1[3], const float v2[3], const float v3[3], float *r_a1, float *r_a2, float *r_a3)
 {
   *r_a1 = p_vec_angle(v3, v1, v2);
   *r_a2 = p_vec_angle(v1, v2, v3);
-  *r_a3 = (float)M_PI - *r_a2 - *r_a1;
+  *r_a3 = p_vec_angle(v2, v3, v1);
+
+  /* Fix for degenerate geometry e.g. v1 = sum(v2 + v3). See T100874 */
+  fix_large_angle(v1, v2, v3, r_a1, r_a2, r_a3);
+  fix_large_angle(v2, v3, v1, r_a2, r_a3, r_a1);
+  fix_large_angle(v3, v1, v2, r_a3, r_a1, r_a2);
+
+  /* Workaround for degenerate geometry, e.g. v1 == v2 == v3. */
+  *r_a1 = max_ff(*r_a1, 0.001f);
+  *r_a2 = max_ff(*r_a2, 0.001f);
+  *r_a3 = max_ff(*r_a3, 0.001f);
 }
 
 static void p_face_angles(PFace *f, float *r_a1, float *r_a2, float *r_a3)
@@ -2266,7 +2324,6 @@ using PAbfSystem = struct PAbfSystem {
   float *bAlpha, *bTriangle, *bInterior;
   float *lambdaTriangle, *lambdaPlanar, *lambdaLength;
   float (*J2dt)[3], *bstar, *dstar;
-  float minangle, maxangle;
 };
 
 static void p_abf_setup_system(PAbfSystem *sys)
@@ -2294,9 +2351,6 @@ static void p_abf_setup_system(PAbfSystem *sys)
   for (i = 0; i < sys->ninterior; i++) {
     sys->lambdaLength[i] = 1.0;
   }
-
-  sys->minangle = 1.0 * M_PI / 180.0;
-  sys->maxangle = (float)M_PI - sys->minangle;
 }
 
 static void p_abf_free_system(PAbfSystem *sys)
@@ -2707,25 +2761,6 @@ static bool p_chart_abf_solve(PChart *chart)
     e3 = e2->next;
     p_face_angles(f, &a1, &a2, &a3);
 
-    if (a1 < sys.minangle) {
-      a1 = sys.minangle;
-    }
-    else if (a1 > sys.maxangle) {
-      a1 = sys.maxangle;
-    }
-    if (a2 < sys.minangle) {
-      a2 = sys.minangle;
-    }
-    else if (a2 > sys.maxangle) {
-      a2 = sys.maxangle;
-    }
-    if (a3 < sys.minangle) {
-      a3 = sys.minangle;
-    }
-    else if (a3 > sys.maxangle) {
-      a3 = sys.maxangle;
-    }
-
     sys.alpha[e1->u.id] = sys.beta[e1->u.id] = a1;
     sys.alpha[e2->u.id] = sys.beta[e2->u.id] = a2;
     sys.alpha[e3->u.id] = sys.beta[e3->u.id] = a3;
diff --git a/source/blender/gpu/GPU_buffers.h b/source/blender/gpu/GPU_buffers.h
index 7af4f968942..74ce4806c3d 100644
--- a/source/blender/gpu/GPU_buffers.h
+++ b/source/blender/gpu/GPU_buffers.h
@@ -49,7 +49,6 @@ typedef struct GPU_PBVH_Buffers GPU_PBVH_Buffers;
  */
 GPU_PBVH_Buffers *GPU_pbvh_mesh_buffers_build(const struct Mesh *mesh,
                                               const struct MLoopTri *looptri,
-                                              const int *sculpt_face_sets,
                                               const int *face_indices,
                                               int face_indices_len);
 
diff --git a/source/blender/gpu/intern/gpu_buffers.c b/source/blender/gpu/intern/gpu_buffers.c
index 8a8c2ba3efe..e82a3833414 100644
--- a/source/blender/gpu/intern/gpu_buffers.c
+++ b/source/blender/gpu/intern/gpu_buffers.c
@@ -210,13 +210,9 @@ static void gpu_pbvh_batch_init(GPU_PBVH_Buffers *buffers, GPUPrimType prim)
 /** \name Mesh PBVH
  * \{ */
 
-static bool gpu_pbvh_is_looptri_visible(const MLoopTri *lt,
-                                        const bool *hide_vert,
-                                        const MLoop *mloop,
-                                        const int *sculpt_face_sets)
+static bool gpu_pbvh_is_looptri_visible(const MLoopTri *lt, const bool *hide_poly)
 {
-  return (!paint_is_face_hidden(lt, hide_vert, mloop) && sculpt_face_sets &&
-          sculpt_face_sets[lt->poly] > SCULPT_FACE_SET_NONE);
+  return !paint_is_face_hidden(lt, hide_poly);
 }
 
 void GPU_pbvh_mesh_buffers_update(PBVHGPUFormat *vbo_id,
@@ -233,8 +229,8 @@ void GPU_pbvh_mesh_buffers_update(PBVHGPUFormat *vbo_id,
   GPUAttrRef vcol_refs[MAX_GPU_ATTR];
   GPUAttrRef cd_uvs[MAX_GPU_ATTR];
 
-  const bool *hide_vert = (const bool *)CustomData_get_layer_named(
-      &mesh->vdata, CD_PROP_BOOL, ".hide_vert");
+  const bool *hide_poly = (const bool *)CustomData_get_layer_named(
+      &mesh->pdata, CD_PROP_BOOL, ".hide_poly");
   const int *material_indices = (const int *)CustomData_get_layer_named(
       &mesh->pdata, CD_PROP_INT32, "material_index");
 
@@ -315,7 +311,7 @@ void GPU_pbvh_mesh_buffers_update(PBVHGPUFormat *vbo_id,
           for (uint i = 0; i < buffers->face_indices_len; i++) {
             const MLoopTri *lt = &buffers->looptri[buffers->face_indices[i]];
 
-            if (!gpu_pbvh_is_looptri_visible(lt, hide_vert, buffers->mloop, sculpt_face_sets)) {
+            if (!gpu_pbvh_is_looptri_visible(lt, hide_poly)) {
               continue;
             }
 
@@ -355,7 +351,7 @@ void GPU_pbvh_mesh_buffers_update(PBVHGPUFormat *vbo_id,
               buffers->mloop[lt->tri[2]].v,
           };
 
-          if (!gpu_pbvh_is_looptri_visible(lt, hide_vert, buffers->mloop, sculpt_face_sets)) {
+          if (!gpu_pbvh_is_looptri_visible(lt, hide_poly)) {
             continue;
           }
 
@@ -395,7 +391,7 @@ void GPU_pbvh_mesh_buffers_update(PBVHGPUFormat *vbo_id,
             buffers->mloop[lt->tri[2]].v,
         };
 
-        if (!gpu_pbvh_is_looptri_visible(lt, hide_vert, buffers->mloop, sculpt_face_sets)) {
+        if (!gpu_pbvh_is_looptri_visible(lt, hide_poly)) {
           continue;
         }
 
@@ -458,7 +454,6 @@ void GPU_pbvh_mesh_buffers_update(PBVHGPUFormat *vbo_id,
 
 GPU_PBVH_Buffers *GPU_pbvh_mesh_buffers_build(const Mesh *mesh,
                                               const MLoopTri *looptri,
-                                              const int *sculpt_face_sets,
                                               const int *face_indices,
                                               const int face_indices_len)
 {
@@ -471,8 +466,8 @@ GPU_PBVH_Buffers *GPU_pbvh_mesh_buffers_build(const Mesh *mesh,
 
   buffers = MEM_callocN(sizeof(GPU_PBVH_Buffers), "GPU_Buffers");
 
-  const bool *hide_vert = (bool *)CustomData_get_layer_named(
-      &mesh->vdata, CD_PROP_BOOL, ".hide_vert");
+  const bool *hide_poly = (bool *)CustomData_get_layer_named(
+      &mesh->pdata, CD_PROP_BOOL, ".hide_poly");
 
   /* smooth or flat for all */
   buffers->smooth = polys[looptri[face_indices[0]].poly].flag & ME_SMOOTH;
@@ -482,7 +477,7 @@ GPU_PBVH_Buffers *GPU_pbvh_mesh_buffers_build(const Mesh *mesh,
   /* Count the number of visible triangles */
   for (i = 0, tottri = 0; i < face_indices_len; i++) {
     const MLoopTri *lt = &looptri[face_indices[i]];
-    if (gpu_pbvh_is_looptri_visible(lt, hide_vert, loops, sculpt_face_sets)) {
+    if (gpu_pbvh_is_looptri_visible(lt, hide_poly)) {
       int r_edges[3];
       BKE_mesh_looptri_get_real_edges(mesh, lt, r_edges);
       for (int j = 0; j < 3; j++) {
@@ -515,7 +510,7 @@ GPU_PBVH_Buffers *GPU_pbvh_mesh_buffers_build(const Mesh *mesh,
     const MLoopTri *lt = &looptri[face_indices[i]];
 
     /* Skip hidden faces */
-    if (!gpu_pbvh_is_looptri_visible(lt, hide_vert, loops, sculpt_face_sets)) {
+    if (!gpu_pbvh_is_looptri_visible(lt, hide_poly)) {
       continue;
     }
 
diff --git a/source/blender/gpu/intern/gpu_shader_builder_stubs.cc b/source/blender/gpu/intern/gpu_shader_builder_stubs.cc
index 0c8cec4e7dc..6202a97901f 100644
--- a/source/blender/gpu/intern/gpu_shader_builder_stubs.cc
+++ b/source/blender/gpu/intern/gpu_shader_builder_stubs.cc
@@ -136,9 +136,7 @@ eAttrDomain BKE_id_attribute_domain(const struct ID *UNUSED(id),
 /* -------------------------------------------------------------------- */
 /** \name Stubs of BKE_paint.h
  * \{ */
-bool paint_is_face_hidden(const struct MLoopTri *UNUSED(lt),
-                          const bool *UNUSED(hide_vert),
-                          const struct MLoop *UNUSED(mloop))
+bool paint_is_face_hidden(const struct MLoopTri *UNUSED(lt), const bool *UNUSED(hide_poly))
 {
   BLI_assert_unreachable();
   return false;
diff --git a/source/blender/imbuf/IMB_imbuf.h b/source/blender/imbuf/IMB_imbuf.h
index 6881916d1d2..7e652e31506 100644
--- a/source/blender/imbuf/IMB_imbuf.h
+++ b/source/blender/imbuf/IMB_imbuf.h
@@ -809,7 +809,7 @@ bool imb_addrectImBuf(struct ImBuf *ibuf);
  */
 void imb_freerectImBuf(struct ImBuf *ibuf);
 
-bool imb_addrectfloatImBuf(struct ImBuf *ibuf);
+bool imb_addrectfloatImBuf(struct ImBuf *ibuf, const unsigned int channels);
 /**
  * Any free `ibuf->rect` frees mipmaps to be sure, creation is in render on first request.
  */
diff --git a/source/blender/imbuf/IMB_imbuf_types.h b/source/blender/imbuf/IMB_imbuf_types.h
index 45d05e9b856..03bb11d0cf6 100644
--- a/source/blender/imbuf/IMB_imbuf_types.h
+++ b/source/blender/imbuf/IMB_imbuf_types.h
@@ -166,8 +166,6 @@ typedef enum eImBufFlags {
  * \{ */
 
 typedef struct ImBuf {
-  struct ImBuf *next, *prev; /** < allow lists of #ImBufs, for caches or flip-books. */
-
   /* dimensions */
   /** Width and Height of our image buffer.
    * Should be 'unsigned int' since most formats use this.
diff --git a/source/blender/imbuf/intern/IMB_filetype.h b/source/blender/imbuf/intern/IMB_filetype.h
index 9a0a6998fab..bd17316d173 100644
--- a/source/blender/imbuf/intern/IMB_filetype.h
+++ b/source/blender/imbuf/intern/IMB_filetype.h
@@ -264,6 +264,12 @@ struct ImBuf *imb_loadwebp(const unsigned char *mem,
                            size_t size,
                            int flags,
                            char colorspace[IM_MAX_SPACE]);
+struct ImBuf *imb_load_filepath_thumbnail_webp(const char *filepath,
+                                               const int flags,
+                                               const size_t max_thumb_size,
+                                               char colorspace[],
+                                               size_t *r_width,
+                                               size_t *r_height);
 bool imb_savewebp(struct ImBuf *ibuf, const char *name, int flags);
 
 /** \} */
diff --git a/source/blender/imbuf/intern/allocimbuf.c b/source/blender/imbuf/intern/allocimbuf.c
index 8b9ad94de0c..868040dc17a 100644
--- a/source/blender/imbuf/intern/allocimbuf.c
+++ b/source/blender/imbuf/intern/allocimbuf.c
@@ -364,7 +364,7 @@ void *imb_alloc_pixels(
   return MEM_callocN(size, name);
 }
 
-bool imb_addrectfloatImBuf(ImBuf *ibuf)
+bool imb_addrectfloatImBuf(ImBuf *ibuf, const unsigned int channels)
 {
   if (ibuf == NULL) {
     return false;
@@ -374,8 +374,8 @@ bool imb_addrectfloatImBuf(ImBuf *ibuf)
     imb_freerectfloatImBuf(ibuf); /* frees mipmap too, hrm */
   }
 
-  ibuf->channels = 4;
-  if ((ibuf->rect_float = imb_alloc_pixels(ibuf->x, ibuf->y, 4, sizeof(float), __func__))) {
+  ibuf->channels = channels;
+  if ((ibuf->rect_float = imb_alloc_pixels(ibuf->x, ibuf->y, channels, sizeof(float), __func__))) {
     ibuf->mall |= IB_rectfloat;
     ibuf->flags |= IB_rectfloat;
     return true;
@@ -536,7 +536,7 @@ bool IMB_initImBuf(
   }
 
   if (flags & IB_rectfloat) {
-    if (imb_addrectfloatImBuf(ibuf) == false) {
+    if (imb_addrectfloatImBuf(ibuf, ibuf->channels) == false) {
       return false;
     }
   }
diff --git a/source/blender/imbuf/intern/filetype.c b/source/blender/imbuf/intern/filetype.c
index 92fa980cd7f..e1d2bea4ae9 100644
--- a/source/blender/imbuf/intern/filetype.c
+++ b/source/blender/imbuf/intern/filetype.c
@@ -217,7 +217,7 @@ const ImFileType IMB_FILE_TYPES[] = {
         .is_a = imb_is_a_webp,
         .load = imb_loadwebp,
         .load_filepath = NULL,
-        .load_filepath_thumbnail = NULL,
+        .load_filepath_thumbnail = imb_load_filepath_thumbnail_webp,
         .save = imb_savewebp,
         .load_tile = NULL,
         .flag = 0,
diff --git a/source/blender/imbuf/intern/openexr/openexr_api.cpp b/source/blender/imbuf/intern/openexr/openexr_api.cpp
index eb6ce5df794..aaeb407abc4 100644
--- a/source/blender/imbuf/intern/openexr/openexr_api.cpp
+++ b/source/blender/imbuf/intern/openexr/openexr_api.cpp
@@ -2058,7 +2058,7 @@ struct ImBuf *imb_load_openexr(const unsigned char *mem,
           size_t xstride = sizeof(float[4]);
           size_t ystride = -xstride * width;
 
-          imb_addrectfloatImBuf(ibuf);
+          imb_addrectfloatImBuf(ibuf, 4);
 
           /* Inverse correct first pixel for data-window
            * coordinates (- dw.min.y because of y flip). */
diff --git a/source/blender/imbuf/intern/png.c b/source/blender/imbuf/intern/png.c
index 4d6dfac0ba0..e27d649ccbe 100644
--- a/source/blender/imbuf/intern/png.c
+++ b/source/blender/imbuf/intern/png.c
@@ -646,7 +646,7 @@ ImBuf *imb_loadpng(const unsigned char *mem, size_t size, int flags, char colors
 
   if (ibuf && ((flags & IB_test) == 0)) {
     if (bit_depth == 16) {
-      imb_addrectfloatImBuf(ibuf);
+      imb_addrectfloatImBuf(ibuf, 4);
       png_set_swap(png_ptr);
 
       pixels16 = imb_alloc_pixels(ibuf->x, ibuf->y, channels, sizeof(png_uint_16), "pixels");
diff --git a/source/blender/imbuf/intern/stereoimbuf.c b/source/blender/imbuf/intern/stereoimbuf.c
index 2a0baaf6172..ba1840a5fcd 100644
--- a/source/blender/imbuf/intern/stereoimbuf.c
+++ b/source/blender/imbuf/intern/stereoimbuf.c
@@ -761,11 +761,14 @@ ImBuf *IMB_stereo3d_ImBuf(const ImageFormatData *im_format, ImBuf *ibuf_left, Im
 
   IMB_stereo3d_write_dimensions(
       im_format->stereo3d_format.display_mode, false, ibuf_left->x, ibuf_left->y, &width, &height);
-  ibuf_stereo = IMB_allocImBuf(
-      width, height, ibuf_left->planes, (is_float ? IB_rectfloat : IB_rect));
+  ibuf_stereo = IMB_allocImBuf(width, height, ibuf_left->planes, 0);
 
-  ibuf_stereo->rect_colorspace = ibuf_left->rect_colorspace;
-  ibuf_stereo->float_colorspace = ibuf_left->float_colorspace;
+  if (is_float) {
+    imb_addrectfloatImBuf(ibuf_stereo, ibuf_left->channels);
+  }
+  else {
+    imb_addrectImBuf(ibuf_stereo);
+  }
 
   ibuf_stereo->flags = ibuf_left->flags;
 
@@ -773,7 +776,7 @@ ImBuf *IMB_stereo3d_ImBuf(const ImageFormatData *im_format, ImBuf *ibuf_left, Im
                          is_float,
                          ibuf_left->x,
                          ibuf_left->y,
-                         4,
+                         ibuf_left->channels,
                          (int *)ibuf_left->rect,
                          (int *)ibuf_right->rect,
                          (int *)ibuf_stereo->rect,
@@ -1286,10 +1289,17 @@ void IMB_ImBufFromStereo3d(const Stereo3dFormat *s3d,
                                &width,
                                &height);
 
-  ibuf_left = IMB_allocImBuf(
-      width, height, ibuf_stereo3d->planes, (is_float ? IB_rectfloat : IB_rect));
-  ibuf_right = IMB_allocImBuf(
-      width, height, ibuf_stereo3d->planes, (is_float ? IB_rectfloat : IB_rect));
+  ibuf_left = IMB_allocImBuf(width, height, ibuf_stereo3d->planes, 0);
+  ibuf_right = IMB_allocImBuf(width, height, ibuf_stereo3d->planes, 0);
+
+  if (is_float) {
+    imb_addrectfloatImBuf(ibuf_left, ibuf_stereo3d->channels);
+    imb_addrectfloatImBuf(ibuf_right, ibuf_stereo3d->channels);
+  }
+  else {
+    imb_addrectImBuf(ibuf_left);
+    imb_addrectImBuf(ibuf_right);
+  }
 
   ibuf_left->flags = ibuf_stereo3d->flags;
   ibuf_right->flags = ibuf_stereo3d->flags;
@@ -1307,7 +1317,7 @@ void IMB_ImBufFromStereo3d(const Stereo3dFormat *s3d,
                          is_float,
                          ibuf_left->x,
                          ibuf_left->y,
-                         4,
+                         ibuf_left->channels,
                          (int *)ibuf_left->rect,
                          (int *)ibuf_right->rect,
                          (int *)ibuf_stereo3d->rect,
diff --git a/source/blender/imbuf/intern/webp.c b/source/blender/imbuf/intern/webp.c
index 19fe2373ea0..94c8e3fb61d 100644
--- a/source/blender/imbuf/intern/webp.c
+++ b/source/blender/imbuf/intern/webp.c
@@ -4,14 +4,23 @@
  *  \ingroup imbuf
  */
 
+#ifdef _WIN32
+#  include <io.h>
+#else
+#  include <unistd.h>
+#endif
+
+#include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <webp/decode.h>
 #include <webp/encode.h>
 
 #include "BLI_fileops.h"
+#include "BLI_mmap.h"
 #include "BLI_utildefines.h"
 
+#include "IMB_allocimbuf.h"
 #include "IMB_colormanagement.h"
 #include "IMB_colormanagement_intern.h"
 #include "IMB_filetype.h"
@@ -67,6 +76,89 @@ ImBuf *imb_loadwebp(const unsigned char *mem,
   return ibuf;
 }
 
+struct ImBuf *imb_load_filepath_thumbnail_webp(const char *filepath,
+                                               const int UNUSED(flags),
+                                               const size_t max_thumb_size,
+                                               char colorspace[],
+                                               size_t *r_width,
+                                               size_t *r_height)
+{
+  const int file = BLI_open(filepath, O_BINARY | O_RDONLY, 0);
+  if (file == -1) {
+    return NULL;
+  }
+
+  const size_t data_size = BLI_file_descriptor_size(file);
+
+  imb_mmap_lock();
+  BLI_mmap_file *mmap_file = BLI_mmap_open(file);
+  imb_mmap_unlock();
+  close(file);
+  if (mmap_file == NULL) {
+    return NULL;
+  }
+
+  const unsigned char *data = BLI_mmap_get_pointer(mmap_file);
+
+  WebPDecoderConfig config;
+  if (!data || !WebPInitDecoderConfig(&config) ||
+      WebPGetFeatures(data, data_size, &config.input) != VP8_STATUS_OK) {
+    fprintf(stderr, "WebP: Invalid file\n");
+    imb_mmap_lock();
+    BLI_mmap_free(mmap_file);
+    imb_mmap_unlock();
+    return NULL;
+  }
+
+  /* Return full size of the image. */
+  *r_width = (size_t)config.input.width;
+  *r_height = (size_t)config.input.height;
+
+  const float scale = (float)max_thumb_size / MAX2(config.input.width, config.input.height);
+  const int dest_w = (int)(config.input.width * scale);
+  const int dest_h = (int)(config.input.height * scale);
+
+  colorspace_set_default_role(colorspace, IM_MAX_SPACE, COLOR_ROLE_DEFAULT_BYTE);
+  struct ImBuf *ibuf = IMB_allocImBuf(dest_w, dest_h, 32, IB_rect);
+  if (ibuf == NULL) {
+    fprintf(stderr, "WebP: Failed to allocate image memory\n");
+    imb_mmap_lock();
+    BLI_mmap_free(mmap_file);
+    imb_mmap_unlock();
+    return NULL;
+  }
+
+  config.options.no_fancy_upsampling = 1;
+  config.options.use_scaling = 1;
+  config.options.scaled_width = dest_w;
+  config.options.scaled_height = dest_h;
+  config.options.bypass_filtering = 1;
+  config.options.use_threads = 0;
+  config.options.flip = 1;
+  config.output.is_external_memory = 1;
+  config.output.colorspace = MODE_RGBA;
+  config.output.u.RGBA.rgba = (uint8_t *)ibuf->rect;
+  config.output.u.RGBA.stride = 4 * ibuf->x;
+  config.output.u.RGBA.size = (size_t)(config.output.u.RGBA.stride * ibuf->y);
+
+  if (WebPDecode(data, data_size, &config) != VP8_STATUS_OK) {
+    fprintf(stderr, "WebP: Failed to decode image\n");
+    imb_mmap_lock();
+    BLI_mmap_free(mmap_file);
+    imb_mmap_unlock();
+    return NULL;
+  }
+
+  /* Free the output buffer. */
+  WebPFreeDecBuffer(&config.output);
+
+  imb_mmap_lock();
+  BLI_mmap_free(mmap_file);
+  imb_mmap_unlock();
+
+  return ibuf;
+}
+
 bool imb_savewebp(struct ImBuf *ibuf, const char *name, int UNUSED(flags))
 {
   const int bytesperpixel = (ibuf->planes + 7) >> 3;
diff --git a/source/blender/io/usd/usd.h b/source/blender/io/usd/usd.h
index a07315d8b4e..3494d8ffdc3 100644
--- a/source/blender/io/usd/usd.h
+++ b/source/blender/io/usd/usd.h
@@ -52,7 +52,7 @@ struct USDImportParams {
   bool import_materials;
   bool import_meshes;
   bool import_volumes;
-  char *prim_path_mask;
+  char prim_path_mask[1024];
   bool import_subdiv;
   bool import_instance_proxies;
   bool create_collection;
diff --git a/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc b/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc
index 4d934960010..27526734624 100644
--- a/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc
+++ b/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc
@@ -558,24 +558,26 @@ void MTLWriter::write_bsdf_properties(const MTLMaterial &mtl)
   /* For various material properties, we only capture information
    * coming from the texture, or the default value of the socket.
    * When the texture is present, do not emit the default value. */
-  if (!mtl.tex_map_of_type(MTLTexMapType::Ns).is_valid()) {
-    fmt_handler_.write_mtl_float("Ns", mtl.Ns);
+  if (!mtl.tex_map_of_type(MTLTexMapType::SpecularExponent).is_valid()) {
+    fmt_handler_.write_mtl_float("Ns", mtl.spec_exponent);
   }
-  fmt_handler_.write_mtl_float3("Ka", mtl.Ka.x, mtl.Ka.y, mtl.Ka.z);
-  if (!mtl.tex_map_of_type(MTLTexMapType::Kd).is_valid()) {
-    fmt_handler_.write_mtl_float3("Kd", mtl.Kd.x, mtl.Kd.y, mtl.Kd.z);
+  fmt_handler_.write_mtl_float3(
+      "Ka", mtl.ambient_color.x, mtl.ambient_color.y, mtl.ambient_color.z);
+  if (!mtl.tex_map_of_type(MTLTexMapType::Color).is_valid()) {
+    fmt_handler_.write_mtl_float3("Kd", mtl.color.x, mtl.color.y, mtl.color.z);
   }
-  if (!mtl.tex_map_of_type(MTLTexMapType::Ks).is_valid()) {
-    fmt_handler_.write_mtl_float3("Ks", mtl.Ks.x, mtl.Ks.y, mtl.Ks.z);
+  if (!mtl.tex_map_of_type(MTLTexMapType::Specular).is_valid()) {
+    fmt_handler_.write_mtl_float3("Ks", mtl.spec_color.x, mtl.spec_color.y, mtl.spec_color.z);
   }
-  if (!mtl.tex_map_of_type(MTLTexMapType::Ke).is_valid()) {
-    fmt_handler_.write_mtl_float3("Ke", mtl.Ke.x, mtl.Ke.y, mtl.Ke.z);
+  if (!mtl.tex_map_of_type(MTLTexMapType::Emission).is_valid()) {
+    fmt_handler_.write_mtl_float3(
+        "Ke", mtl.emission_color.x, mtl.emission_color.y, mtl.emission_color.z);
   }
-  fmt_handler_.write_mtl_float("Ni", mtl.Ni);
-  if (!mtl.tex_map_of_type(MTLTexMapType::d).is_valid()) {
-    fmt_handler_.write_mtl_float("d", mtl.d);
+  fmt_handler_.write_mtl_float("Ni", mtl.ior);
+  if (!mtl.tex_map_of_type(MTLTexMapType::Alpha).is_valid()) {
+    fmt_handler_.write_mtl_float("d", mtl.alpha);
   }
-  fmt_handler_.write_mtl_illum(mtl.illum);
+  fmt_handler_.write_mtl_illum(mtl.illum_mode);
 }
 
 void MTLWriter::write_texture_map(const MTLMaterial &mtl_material,
@@ -594,8 +596,8 @@ void MTLWriter::write_texture_map(const MTLMaterial &mtl_material,
   if (texture_map.scale != float3{1.0f, 1.0f, 1.0f}) {
     options.append(" -s ").append(float3_to_string(texture_map.scale));
   }
-  if (texture_key == MTLTexMapType::bump && mtl_material.map_Bump_strength > 0.0001f) {
-    options.append(" -bm ").append(std::to_string(mtl_material.map_Bump_strength));
+  if (texture_key == MTLTexMapType::Normal && mtl_material.normal_strength > 0.0001f) {
+    options.append(" -bm ").append(std::to_string(mtl_material.normal_strength));
   }
 
   std::string path = path_reference(
diff --git a/source/blender/io/wavefront_obj/exporter/obj_export_mtl.cc b/source/blender/io/wavefront_obj/exporter/obj_export_mtl.cc
index 6a02695c304..77cad18a040 100644
--- a/source/blender/io/wavefront_obj/exporter/obj_export_mtl.cc
+++ b/source/blender/io/wavefront_obj/exporter/obj_export_mtl.cc
@@ -212,11 +212,11 @@ static void store_bsdf_properties(const bNode *bsdf_node,
     copy_property_from_node(SOCK_FLOAT, bsdf_node, "IOR", {&refraction_index, 1});
   }
 
-  float dissolved = material->a;
+  float alpha = material->a;
   if (bsdf_node) {
-    copy_property_from_node(SOCK_FLOAT, bsdf_node, "Alpha", {&dissolved, 1});
+    copy_property_from_node(SOCK_FLOAT, bsdf_node, "Alpha", {&alpha, 1});
   }
-  const bool transparent = dissolved != 1.0f;
+  const bool transparent = alpha != 1.0f;
 
   float3 diffuse_col = {material->r, material->g, material->b};
   if (bsdf_node) {
@@ -253,19 +253,19 @@ static void store_bsdf_properties(const bNode *bsdf_node,
     /* Transparency: Glass on, Reflection: Ray trace off */
     illum = 9;
   }
-  r_mtl_mat.Ns = spec_exponent;
+  r_mtl_mat.spec_exponent = spec_exponent;
   if (metallic != 0.0f) {
-    r_mtl_mat.Ka = {metallic, metallic, metallic};
+    r_mtl_mat.ambient_color = {metallic, metallic, metallic};
   }
   else {
-    r_mtl_mat.Ka = {1.0f, 1.0f, 1.0f};
+    r_mtl_mat.ambient_color = {1.0f, 1.0f, 1.0f};
   }
-  r_mtl_mat.Kd = diffuse_col;
-  r_mtl_mat.Ks = {specular, specular, specular};
-  r_mtl_mat.Ke = emission_col;
-  r_mtl_mat.Ni = refraction_index;
-  r_mtl_mat.d = dissolved;
-  r_mtl_mat.illum = illum;
+  r_mtl_mat.color = diffuse_col;
+  r_mtl_mat.spec_color = {specular, specular, specular};
+  r_mtl_mat.emission_color = emission_col;
+  r_mtl_mat.ior = refraction_index;
+  r_mtl_mat.alpha = alpha;
+  r_mtl_mat.illum_mode = illum;
 }
 
 /**
@@ -291,7 +291,7 @@ static void store_image_textures(const bNode *bsdf_node,
     Vector<const bNodeSocket *> linked_sockets;
     const bNode *normal_map_node{nullptr};
 
-    if (key == (int)MTLTexMapType::bump) {
+    if (key == (int)MTLTexMapType::Normal) {
       /* Find sockets linked to destination "Normal" socket in P-BSDF node. */
       linked_sockets_to_dest_id(bsdf_node, *node_tree, "Normal", linked_sockets);
       /* Among the linked sockets, find Normal Map shader node. */
@@ -302,7 +302,7 @@ static void store_image_textures(const bNode *bsdf_node,
     }
     else {
       /* Skip emission map if emission strength is zero. */
-      if (key == (int)MTLTexMapType::Ke) {
+      if (key == (int)MTLTexMapType::Emission) {
         float emission_strength = 0.0f;
         copy_property_from_node(
             SOCK_FLOAT, bsdf_node, "Emission Strength", {&emission_strength, 1});
@@ -331,7 +331,7 @@ static void store_image_textures(const bNode *bsdf_node,
 
     if (normal_map_node) {
       copy_property_from_node(
-          SOCK_FLOAT, normal_map_node, "Strength", {&r_mtl_mat.map_Bump_strength, 1});
+          SOCK_FLOAT, normal_map_node, "Strength", {&r_mtl_mat.normal_strength, 1});
     }
     /* Texture transform options. Only translation (origin offset, "-o") and scale
      * ("-o") are supported. */
diff --git a/source/blender/io/wavefront_obj/exporter/obj_export_mtl.hh b/source/blender/io/wavefront_obj/exporter/obj_export_mtl.hh
index d8eafff107b..0b94e4e43a3 100644
--- a/source/blender/io/wavefront_obj/exporter/obj_export_mtl.hh
+++ b/source/blender/io/wavefront_obj/exporter/obj_export_mtl.hh
@@ -13,7 +13,16 @@ struct Material;
 
 namespace blender::io::obj {
 
-enum class MTLTexMapType { Kd = 0, Ks, Ns, d, refl, Ke, bump, Count };
+enum class MTLTexMapType {
+  Color = 0,
+  Specular,
+  SpecularExponent,
+  Alpha,
+  Reflection,
+  Emission,
+  Normal,
+  Count
+};
 extern const char *tex_map_type_to_socket_id[];
 
 struct MTLTexMap {
@@ -47,17 +56,17 @@ struct MTLMaterial {
   std::string name;
   /* Always check for negative values while importing or exporting. Use defaults if
    * any value is negative. */
-  float Ns{-1.0f};
-  float3 Ka{-1.0f};
-  float3 Kd{-1.0f};
-  float3 Ks{-1.0f};
-  float3 Ke{-1.0f};
-  float Ni{-1.0f};
-  float d{-1.0f};
-  int illum{-1};
+  float spec_exponent{-1.0f};   /* Ns */
+  float3 ambient_color{-1.0f};  /* Ka */
+  float3 color{-1.0f};          /* Kd */
+  float3 spec_color{-1.0f};     /* Ks */
+  float3 emission_color{-1.0f}; /* Ke */
+  float ior{-1.0f};             /* Ni */
+  float alpha{-1.0f};           /* d */
+  int illum_mode{-1};
   MTLTexMap texture_maps[(int)MTLTexMapType::Count];
-  /** Only used for Normal Map node: "map_Bump". */
-  float map_Bump_strength{-1.0f};
+  /* Only used for Normal Map node: "map_Bump". */
+  float normal_strength{-1.0f};
 };
 
 MTLMaterial mtlmaterial_for_material(const Material *material);
diff --git a/source/blender/io/wavefront_obj/importer/obj_import_file_reader.cc b/source/blender/io/wavefront_obj/importer/obj_import_file_reader.cc
index 2ad8a09bd90..cc98dbdbf92 100644
--- a/source/blender/io/wavefront_obj/importer/obj_import_file_reader.cc
+++ b/source/blender/io/wavefront_obj/importer/obj_import_file_reader.cc
@@ -596,26 +596,26 @@ void OBJParser::parse(Vector<std::unique_ptr<Geometry>> &r_all_geometries,
 static MTLTexMapType mtl_line_start_to_texture_type(const char *&p, const char *end)
 {
   if (parse_keyword(p, end, "map_Kd")) {
-    return MTLTexMapType::Kd;
+    return MTLTexMapType::Color;
   }
   if (parse_keyword(p, end, "map_Ks")) {
-    return MTLTexMapType::Ks;
+    return MTLTexMapType::Specular;
   }
   if (parse_keyword(p, end, "map_Ns")) {
-    return MTLTexMapType::Ns;
+    return MTLTexMapType::SpecularExponent;
   }
   if (parse_keyword(p, end, "map_d")) {
-    return MTLTexMapType::d;
+    return MTLTexMapType::Alpha;
   }
   if (parse_keyword(p, end, "refl") || parse_keyword(p, end, "map_refl")) {
-    return MTLTexMapType::refl;
+    return MTLTexMapType::Reflection;
   }
   if (parse_keyword(p, end, "map_Ke")) {
-    return MTLTexMapType::Ke;
+    return MTLTexMapType::Emission;
   }
   if (parse_keyword(p, end, "bump") || parse_keyword(p, end, "map_Bump") ||
       parse_keyword(p, end, "map_bump")) {
-    return MTLTexMapType::bump;
+    return MTLTexMapType::Normal;
   }
   return MTLTexMapType::Count;
 }
@@ -647,7 +647,7 @@ static bool parse_texture_option(const char *&p,
     return true;
   }
   if (parse_keyword(p, end, "-bm")) {
-    p = parse_float(p, end, 1.0f, material->map_Bump_strength, true, true);
+    p = parse_float(p, end, 1.0f, material->normal_strength, true, true);
     return true;
   }
   if (parse_keyword(p, end, "-type")) {
@@ -780,31 +780,31 @@ void MTLParser::parse_and_store(Map<string, std::unique_ptr<MTLMaterial>> &r_mat
     }
     else if (material != nullptr) {
       if (parse_keyword(p, end, "Ns")) {
-        parse_float(p, end, 324.0f, material->Ns);
+        parse_float(p, end, 324.0f, material->spec_exponent);
       }
       else if (parse_keyword(p, end, "Ka")) {
-        parse_floats(p, end, 0.0f, material->Ka, 3);
+        parse_floats(p, end, 0.0f, material->ambient_color, 3);
       }
       else if (parse_keyword(p, end, "Kd")) {
-        parse_floats(p, end, 0.8f, material->Kd, 3);
+        parse_floats(p, end, 0.8f, material->color, 3);
       }
       else if (parse_keyword(p, end, "Ks")) {
-        parse_floats(p, end, 0.5f, material->Ks, 3);
+        parse_floats(p, end, 0.5f, material->spec_color, 3);
       }
       else if (parse_keyword(p, end, "Ke")) {
-        parse_floats(p, end, 0.0f, material->Ke, 3);
+        parse_floats(p, end, 0.0f, material->emission_color, 3);
       }
       else if (parse_keyword(p, end, "Ni")) {
-        parse_float(p, end, 1.45f, material->Ni);
+        parse_float(p, end, 1.45f, material->ior);
       }
       else if (parse_keyword(p, end, "d")) {
-        parse_float(p, end, 1.0f, material->d);
+        parse_float(p, end, 1.0f, material->alpha);
       }
       else if (parse_keyword(p, end, "illum")) {
         /* Some files incorrectly use a float (T60135). */
         float val;
         parse_float(p, end, 1.0f, val);
-        material->illum = val;
+        material->illum_mode = val;
       }
       else {
         parse_texture_map(p, end, material, mtl_dir_path_);
diff --git a/source/blender/io/wavefront_obj/importer/obj_import_mtl.cc b/source/blender/io/wavefront_obj/importer/obj_import_mtl.cc
index 0922a71979e..76568b2ddb4 100644
--- a/source/blender/io/wavefront_obj/importer/obj_import_mtl.cc
+++ b/source/blender/io/wavefront_obj/importer/obj_import_mtl.cc
@@ -178,7 +178,7 @@ static void link_sockets(bNodeTree *ntree,
 
 static void set_bsdf_socket_values(bNode *bsdf, Material *mat, const MTLMaterial &mtl_mat)
 {
-  const int illum = mtl_mat.illum;
+  const int illum = mtl_mat.illum_mode;
   bool do_highlight = false;
   bool do_tranparency = false;
   bool do_reflection = false;
@@ -244,21 +244,23 @@ static void set_bsdf_socket_values(bNode *bsdf, Material *mat, const MTLMaterial
   /* Approximations for trying to map obj/mtl material model into
    * Principled BSDF: */
   /* Specular: average of Ks components. */
-  float specular = (mtl_mat.Ks[0] + mtl_mat.Ks[1] + mtl_mat.Ks[2]) / 3;
+  float specular = (mtl_mat.spec_color[0] + mtl_mat.spec_color[1] + mtl_mat.spec_color[2]) / 3;
   if (specular < 0.0f) {
     specular = do_highlight ? 1.0f : 0.0f;
   }
   /* Roughness: map 0..1000 range to 1..0 and apply non-linearity. */
   float roughness;
-  if (mtl_mat.Ns < 0.0f) {
+  if (mtl_mat.spec_exponent < 0.0f) {
     roughness = do_highlight ? 0.0f : 1.0f;
   }
   else {
-    float clamped_ns = std::max(0.0f, std::min(1000.0f, mtl_mat.Ns));
+    float clamped_ns = std::max(0.0f, std::min(1000.0f, mtl_mat.spec_exponent));
     roughness = 1.0f - sqrt(clamped_ns / 1000.0f);
   }
   /* Metallic: average of Ka components. */
-  float metallic = (mtl_mat.Ka[0] + mtl_mat.Ka[1] + mtl_mat.Ka[2]) / 3;
+  float metallic = (mtl_mat.ambient_color[0] + mtl_mat.ambient_color[1] +
+                    mtl_mat.ambient_color[2]) /
+                   3;
   if (do_reflection) {
     if (metallic < 0.0f) {
       metallic = 1.0f;
@@ -268,7 +270,7 @@ static void set_bsdf_socket_values(bNode *bsdf, Material *mat, const MTLMaterial
     metallic = 0.0f;
   }
 
-  float ior = mtl_mat.Ni;
+  float ior = mtl_mat.ior;
   if (ior < 0) {
     if (do_tranparency) {
       ior = 1.0f;
@@ -277,12 +279,12 @@ static void set_bsdf_socket_values(bNode *bsdf, Material *mat, const MTLMaterial
       ior = 1.5f;
     }
   }
-  float alpha = mtl_mat.d;
+  float alpha = mtl_mat.alpha;
   if (do_tranparency && alpha < 0) {
     alpha = 1.0f;
   }
 
-  float3 base_color = {mtl_mat.Kd[0], mtl_mat.Kd[1], mtl_mat.Kd[2]};
+  float3 base_color = mtl_mat.color;
   if (base_color.x >= 0 && base_color.y >= 0 && base_color.z >= 0) {
     set_property_of_socket(SOCK_RGBA, "Base Color", {base_color, 3}, bsdf);
     /* Viewport shading uses legacy r,g,b base color. */
@@ -291,11 +293,11 @@ static void set_bsdf_socket_values(bNode *bsdf, Material *mat, const MTLMaterial
     mat->b = base_color.z;
   }
 
-  float3 emission_color = {mtl_mat.Ke[0], mtl_mat.Ke[1], mtl_mat.Ke[2]};
+  float3 emission_color = mtl_mat.emission_color;
   if (emission_color.x >= 0 && emission_color.y >= 0 && emission_color.z >= 0) {
     set_property_of_socket(SOCK_RGBA, "Emission", {emission_color, 3}, bsdf);
   }
-  if (mtl_mat.tex_map_of_type(MTLTexMapType::Ke).is_valid()) {
+  if (mtl_mat.tex_map_of_type(MTLTexMapType::Emission).is_valid()) {
     set_property_of_socket(SOCK_FLOAT, "Emission Strength", {1.0f}, bsdf);
   }
   set_property_of_socket(SOCK_FLOAT, "Specular", {specular}, bsdf);
@@ -341,9 +343,9 @@ static void add_image_textures(Main *bmain,
 
     /* Add normal map node if needed. */
     bNode *normal_map = nullptr;
-    if (key == (int)MTLTexMapType::bump) {
+    if (key == (int)MTLTexMapType::Normal) {
       normal_map = add_node(ntree, SH_NODE_NORMAL_MAP, node_locx_normalmap, node_locy);
-      const float bump = std::max(0.0f, mtl_mat.map_Bump_strength);
+      const float bump = std::max(0.0f, mtl_mat.normal_strength);
       set_property_of_socket(SOCK_FLOAT, "Strength", {bump}, normal_map);
     }
 
@@ -362,7 +364,7 @@ static void add_image_textures(Main *bmain,
       link_sockets(ntree, image_node, "Color", normal_map, "Color");
       link_sockets(ntree, normal_map, "Normal", bsdf, "Normal");
     }
-    else if (key == (int)MTLTexMapType::d) {
+    else if (key == (int)MTLTexMapType::Alpha) {
       link_sockets(ntree, image_node, "Alpha", bsdf, tex_map_type_to_socket_id[key]);
       mat->blend_method = MA_BM_BLEND;
     }
diff --git a/source/blender/io/wavefront_obj/tests/obj_mtl_parser_tests.cc b/source/blender/io/wavefront_obj/tests/obj_mtl_parser_tests.cc
index 5691aa5bea1..ff9485e99b5 100644
--- a/source/blender/io/wavefront_obj/tests/obj_mtl_parser_tests.cc
+++ b/source/blender/io/wavefront_obj/tests/obj_mtl_parser_tests.cc
@@ -50,15 +50,15 @@ class obj_mtl_parser_test : public testing::Test {
       }
       const MTLMaterial &got = *materials.lookup(exp.name);
       const float tol = 0.0001f;
-      EXPECT_V3_NEAR(exp.Ka, got.Ka, tol);
-      EXPECT_V3_NEAR(exp.Kd, got.Kd, tol);
-      EXPECT_V3_NEAR(exp.Ks, got.Ks, tol);
-      EXPECT_V3_NEAR(exp.Ke, got.Ke, tol);
-      EXPECT_NEAR(exp.Ns, got.Ns, tol);
-      EXPECT_NEAR(exp.Ni, got.Ni, tol);
-      EXPECT_NEAR(exp.d, got.d, tol);
-      EXPECT_NEAR(exp.map_Bump_strength, got.map_Bump_strength, tol);
-      EXPECT_EQ(exp.illum, got.illum);
+      EXPECT_V3_NEAR(exp.ambient_color, got.ambient_color, tol);
+      EXPECT_V3_NEAR(exp.color, got.color, tol);
+      EXPECT_V3_NEAR(exp.spec_color, got.spec_color, tol);
+      EXPECT_V3_NEAR(exp.emission_color, got.emission_color, tol);
+      EXPECT_NEAR(exp.spec_exponent, got.spec_exponent, tol);
+      EXPECT_NEAR(exp.ior, got.ior, tol);
+      EXPECT_NEAR(exp.alpha, got.alpha, tol);
+      EXPECT_NEAR(exp.normal_strength, got.normal_strength, tol);
+      EXPECT_EQ(exp.illum_mode, got.illum_mode);
       for (int key = 0; key < (int)MTLTexMapType::Count; key++) {
         const MTLTexMap &exp_tex = exp.texture_maps[key];
         const MTLTexMap &got_tex = got.texture_maps[key];
@@ -102,20 +102,20 @@ TEST_F(obj_mtl_parser_test, string_newlines_whitespace)
       "map_Ks sometex_s_spaces_after_name.png   \t   \r\n";
   MTLMaterial mat[6];
   mat[0].name = "simple";
-  mat[0].Ka = {0.1f, 0.2f, 0.3f};
-  mat[0].illum = 4;
+  mat[0].ambient_color = {0.1f, 0.2f, 0.3f};
+  mat[0].illum_mode = 4;
   mat[1].name = "tab_indentation";
-  mat[1].Kd = {0.2f, 0.3f, 0.4f};
+  mat[1].color = {0.2f, 0.3f, 0.4f};
   mat[2].name = "space_after_name";
-  mat[2].Ks = {0.4f, 0.5f, 0.6f};
+  mat[2].spec_color = {0.4f, 0.5f, 0.6f};
   mat[3].name = "space_before_name";
   mat[4].name = "indented_values";
-  mat[4].Ka = {0.5f, 0.6f, 0.7f};
-  mat[4].Kd = {0.6f, 0.7f, 0.8f};
+  mat[4].ambient_color = {0.5f, 0.6f, 0.7f};
+  mat[4].color = {0.6f, 0.7f, 0.8f};
   mat[5].name = "crlf_ending";
-  mat[5].Ns = 5.0f;
-  mat[5].tex_map_of_type(MTLTexMapType::Kd).image_path = "sometex_d.png";
-  mat[5].tex_map_of_type(MTLTexMapType::Ks).image_path = "sometex_s_spaces_after_name.png";
+  mat[5].spec_exponent = 5.0f;
+  mat[5].tex_map_of_type(MTLTexMapType::Color).image_path = "sometex_d.png";
+  mat[5].tex_map_of_type(MTLTexMapType::Specular).image_path = "sometex_s_spaces_after_name.png";
   check_string(text, mat, ARRAY_SIZE(mat));
 }
 
@@ -123,8 +123,8 @@ TEST_F(obj_mtl_parser_test, cube)
 {
   MTLMaterial mat;
   mat.name = "red";
-  mat.Ka = {0.2f, 0.2f, 0.2f};
-  mat.Kd = {1, 0, 0};
+  mat.ambient_color = {0.2f, 0.2f, 0.2f};
+  mat.color = {1, 0, 0};
   check("cube.mtl", &mat, 1);
 }
 
@@ -132,28 +132,28 @@ TEST_F(obj_mtl_parser_test, all_objects)
 {
   MTLMaterial mat[7];
   for (auto &m : mat) {
-    m.Ka = {1, 1, 1};
-    m.Ks = {0.5f, 0.5f, 0.5f};
-    m.Ke = {0, 0, 0};
-    m.Ns = 250;
-    m.Ni = 1;
-    m.d = 1;
-    m.illum = 2;
+    m.ambient_color = {1, 1, 1};
+    m.spec_color = {0.5f, 0.5f, 0.5f};
+    m.emission_color = {0, 0, 0};
+    m.spec_exponent = 250;
+    m.ior = 1;
+    m.alpha = 1;
+    m.illum_mode = 2;
   }
   mat[0].name = "Blue";
-  mat[0].Kd = {0, 0, 1};
+  mat[0].color = {0, 0, 1};
   mat[1].name = "BlueDark";
-  mat[1].Kd = {0, 0, 0.5f};
+  mat[1].color = {0, 0, 0.5f};
   mat[2].name = "Green";
-  mat[2].Kd = {0, 1, 0};
+  mat[2].color = {0, 1, 0};
   mat[3].name = "GreenDark";
-  mat[3].Kd = {0, 0.5f, 0};
+  mat[3].color = {0, 0.5f, 0};
   mat[4].name = "Material";
-  mat[4].Kd = {0.8f, 0.8f, 0.8f};
+  mat[4].color = {0.8f, 0.8f, 0.8f};
   mat[5].name = "Red";
-  mat[5].Kd = {1, 0, 0};
+  mat[5].color = {1, 0, 0};
   mat[6].name = "RedDark";
-  mat[6].Kd = {0.5f, 0, 0};
+  mat[6].color = {0.5f, 0, 0};
   check("all_objects.mtl", mat, ARRAY_SIZE(mat));
 }
 
@@ -161,92 +161,92 @@ TEST_F(obj_mtl_parser_test, materials)
 {
   MTLMaterial mat[6];
   mat[0].name = "no_textures_red";
-  mat[0].Ka = {0.3f, 0.3f, 0.3f};
-  mat[0].Kd = {0.8f, 0.3f, 0.1f};
-  mat[0].Ns = 5.624998f;
+  mat[0].ambient_color = {0.3f, 0.3f, 0.3f};
+  mat[0].color = {0.8f, 0.3f, 0.1f};
+  mat[0].spec_exponent = 5.624998f;
 
   mat[1].name = "four_maps";
-  mat[1].Ka = {1, 1, 1};
-  mat[1].Kd = {0.8f, 0.8f, 0.8f};
-  mat[1].Ks = {0.5f, 0.5f, 0.5f};
-  mat[1].Ke = {0, 0, 0};
-  mat[1].Ns = 1000;
-  mat[1].Ni = 1.45f;
-  mat[1].d = 1;
-  mat[1].illum = 2;
-  mat[1].map_Bump_strength = 1;
+  mat[1].ambient_color = {1, 1, 1};
+  mat[1].color = {0.8f, 0.8f, 0.8f};
+  mat[1].spec_color = {0.5f, 0.5f, 0.5f};
+  mat[1].emission_color = {0, 0, 0};
+  mat[1].spec_exponent = 1000;
+  mat[1].ior = 1.45f;
+  mat[1].alpha = 1;
+  mat[1].illum_mode = 2;
+  mat[1].normal_strength = 1;
   {
-    MTLTexMap &kd = mat[1].tex_map_of_type(MTLTexMapType::Kd);
+    MTLTexMap &kd = mat[1].tex_map_of_type(MTLTexMapType::Color);
     kd.image_path = "texture.png";
-    MTLTexMap &ns = mat[1].tex_map_of_type(MTLTexMapType::Ns);
+    MTLTexMap &ns = mat[1].tex_map_of_type(MTLTexMapType::SpecularExponent);
     ns.image_path = "sometexture_Roughness.png";
-    MTLTexMap &refl = mat[1].tex_map_of_type(MTLTexMapType::refl);
+    MTLTexMap &refl = mat[1].tex_map_of_type(MTLTexMapType::Reflection);
     refl.image_path = "sometexture_Metallic.png";
-    MTLTexMap &bump = mat[1].tex_map_of_type(MTLTexMapType::bump);
+    MTLTexMap &bump = mat[1].tex_map_of_type(MTLTexMapType::Normal);
     bump.image_path = "sometexture_Normal.png";
   }
 
   mat[2].name = "Clay";
-  mat[2].Ka = {1, 1, 1};
-  mat[2].Kd = {0.8f, 0.682657f, 0.536371f};
-  mat[2].Ks = {0.5f, 0.5f, 0.5f};
-  mat[2].Ke = {0, 0, 0};
-  mat[2].Ns = 440.924042f;
-  mat[2].Ni = 1.45f;
-  mat[2].d = 1;
-  mat[2].illum = 2;
+  mat[2].ambient_color = {1, 1, 1};
+  mat[2].color = {0.8f, 0.682657f, 0.536371f};
+  mat[2].spec_color = {0.5f, 0.5f, 0.5f};
+  mat[2].emission_color = {0, 0, 0};
+  mat[2].spec_exponent = 440.924042f;
+  mat[2].ior = 1.45f;
+  mat[2].alpha = 1;
+  mat[2].illum_mode = 2;
 
   mat[3].name = "Hat";
-  mat[3].Ka = {1, 1, 1};
-  mat[3].Kd = {0.8f, 0.8f, 0.8f};
-  mat[3].Ks = {0.5f, 0.5f, 0.5f};
-  mat[3].Ns = 800;
-  mat[3].map_Bump_strength = 0.5f;
+  mat[3].ambient_color = {1, 1, 1};
+  mat[3].color = {0.8f, 0.8f, 0.8f};
+  mat[3].spec_color = {0.5f, 0.5f, 0.5f};
+  mat[3].spec_exponent = 800;
+  mat[3].normal_strength = 0.5f;
   {
-    MTLTexMap &kd = mat[3].tex_map_of_type(MTLTexMapType::Kd);
+    MTLTexMap &kd = mat[3].tex_map_of_type(MTLTexMapType::Color);
     kd.image_path = "someHatTexture_BaseColor.jpg";
-    MTLTexMap &ns = mat[3].tex_map_of_type(MTLTexMapType::Ns);
+    MTLTexMap &ns = mat[3].tex_map_of_type(MTLTexMapType::SpecularExponent);
     ns.image_path = "someHatTexture_Roughness.jpg";
-    MTLTexMap &refl = mat[3].tex_map_of_type(MTLTexMapType::refl);
+    MTLTexMap &refl = mat[3].tex_map_of_type(MTLTexMapType::Reflection);
     refl.image_path = "someHatTexture_Metalness.jpg";
-    MTLTexMap &bump = mat[3].tex_map_of_type(MTLTexMapType::bump);
+    MTLTexMap &bump = mat[3].tex_map_of_type(MTLTexMapType::Normal);
     bump.image_path = "someHatTexture_Normal.jpg";
   }
 
   mat[4].name = "Parser_Test";
-  mat[4].Ka = {0.1f, 0.2f, 0.3f};
-  mat[4].Kd = {0.4f, 0.5f, 0.6f};
-  mat[4].Ks = {0.7f, 0.8f, 0.9f};
-  mat[4].illum = 6;
-  mat[4].Ns = 15.5;
-  mat[4].Ni = 1.5;
-  mat[4].d = 0.5;
-  mat[4].map_Bump_strength = 0.1f;
+  mat[4].ambient_color = {0.1f, 0.2f, 0.3f};
+  mat[4].color = {0.4f, 0.5f, 0.6f};
+  mat[4].spec_color = {0.7f, 0.8f, 0.9f};
+  mat[4].illum_mode = 6;
+  mat[4].spec_exponent = 15.5;
+  mat[4].ior = 1.5;
+  mat[4].alpha = 0.5;
+  mat[4].normal_strength = 0.1f;
   {
-    MTLTexMap &kd = mat[4].tex_map_of_type(MTLTexMapType::Kd);
+    MTLTexMap &kd = mat[4].tex_map_of_type(MTLTexMapType::Color);
     kd.image_path = "sometex_d.png";
-    MTLTexMap &ns = mat[4].tex_map_of_type(MTLTexMapType::Ns);
+    MTLTexMap &ns = mat[4].tex_map_of_type(MTLTexMapType::SpecularExponent);
     ns.image_path = "sometex_ns.psd";
-    MTLTexMap &refl = mat[4].tex_map_of_type(MTLTexMapType::refl);
+    MTLTexMap &refl = mat[4].tex_map_of_type(MTLTexMapType::Reflection);
     refl.image_path = "clouds.tiff";
     refl.scale = {1.5f, 2.5f, 3.5f};
     refl.translation = {4.5f, 5.5f, 6.5f};
     refl.projection_type = SHD_PROJ_SPHERE;
-    MTLTexMap &bump = mat[4].tex_map_of_type(MTLTexMapType::bump);
+    MTLTexMap &bump = mat[4].tex_map_of_type(MTLTexMapType::Normal);
     bump.image_path = "somebump.tga";
     bump.scale = {3, 4, 5};
   }
 
   mat[5].name = "Parser_ScaleOffset_Test";
   {
-    MTLTexMap &kd = mat[5].tex_map_of_type(MTLTexMapType::Kd);
+    MTLTexMap &kd = mat[5].tex_map_of_type(MTLTexMapType::Color);
     kd.translation = {2.5f, 0.0f, 0.0f};
     kd.image_path = "OffsetOneValue.png";
-    MTLTexMap &ks = mat[5].tex_map_of_type(MTLTexMapType::Ks);
+    MTLTexMap &ks = mat[5].tex_map_of_type(MTLTexMapType::Specular);
     ks.scale = {1.5f, 2.5f, 1.0f};
     ks.translation = {3.5f, 4.5f, 0.0f};
     ks.image_path = "ScaleOffsetBothTwovalues.png";
-    MTLTexMap &ns = mat[5].tex_map_of_type(MTLTexMapType::Ns);
+    MTLTexMap &ns = mat[5].tex_map_of_type(MTLTexMapType::SpecularExponent);
     ns.scale = {0.5f, 1.0f, 1.0f};
     ns.image_path = "1.Value.png";
   }
diff --git a/source/blender/makesrna/intern/rna_object.c b/source/blender/makesrna/intern/rna_object.c
index 6cbc24db2d8..cfc3a832166 100644
--- a/source/blender/makesrna/intern/rna_object.c
+++ b/source/blender/makesrna/intern/rna_object.c
@@ -500,7 +500,7 @@ void rna_Object_data_update(Main *bmain, Scene *scene, PointerRNA *ptr)
   Object *object = (Object *)ptr->data;
 
   if (object->mode == OB_MODE_SCULPT) {
-    BKE_sculpt_ensure_orig_mesh_data(scene, object);
+    BKE_sculpt_ensure_orig_mesh_data(object);
   }
 
   rna_Object_internal_update_data_dependency(bmain, scene, ptr);
diff --git a/source/blender/makesrna/intern/rna_userdef.c b/source/blender/makesrna/intern/rna_userdef.c
index 61d4edccb06..0031e023d39 100644
--- a/source/blender/makesrna/intern/rna_userdef.c
+++ b/source/blender/makesrna/intern/rna_userdef.c
@@ -6377,7 +6377,7 @@ static void rna_def_userdef_experimental(BlenderRNA *brna)
   RNA_def_property_boolean_sdna(prop, NULL, "use_viewport_debug", 1);
   RNA_def_property_ui_text(prop,
                            "Viewport Debug",
-                           "Enable viewport debugging options for developpers in the overlays "
+                           "Enable viewport debugging options for developers in the overlays "
                            "pop-over");
   RNA_def_property_update(prop, 0, "rna_userdef_ui_update");
 }
diff --git a/source/blender/nodes/geometry/nodes/node_geo_extrude_mesh.cc b/source/blender/nodes/geometry/nodes/node_geo_extrude_mesh.cc
index 3d45cb0d817..2295ae49174 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_extrude_mesh.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_extrude_mesh.cc
@@ -94,24 +94,24 @@ static void expand_mesh(Mesh &mesh,
                         const int loop_expand)
 {
   if (vert_expand != 0) {
-    CustomData_duplicate_referenced_layers(&mesh.vdata, mesh.totvert);
+    const int old_verts_num = mesh.totvert;
     mesh.totvert += vert_expand;
-    CustomData_realloc(&mesh.vdata, mesh.totvert);
+    CustomData_realloc(&mesh.vdata, old_verts_num, mesh.totvert);
   }
   if (edge_expand != 0) {
-    CustomData_duplicate_referenced_layers(&mesh.edata, mesh.totedge);
+    const int old_edges_num = mesh.totedge;
     mesh.totedge += edge_expand;
-    CustomData_realloc(&mesh.edata, mesh.totedge);
+    CustomData_realloc(&mesh.edata, old_edges_num, mesh.totedge);
   }
   if (poly_expand != 0) {
-    CustomData_duplicate_referenced_layers(&mesh.pdata, mesh.totpoly);
+    const int old_polys_num = mesh.totpoly;
     mesh.totpoly += poly_expand;
-    CustomData_realloc(&mesh.pdata, mesh.totpoly);
+    CustomData_realloc(&mesh.pdata, old_polys_num, mesh.totpoly);
   }
   if (loop_expand != 0) {
-    CustomData_duplicate_referenced_layers(&mesh.ldata, mesh.totloop);
+    const int old_loops_num = mesh.totloop;
     mesh.totloop += loop_expand;
-    CustomData_realloc(&mesh.ldata, mesh.totloop);
+    CustomData_realloc(&mesh.ldata, old_loops_num, mesh.totloop);
   }
 }
 
@@ -147,6 +147,7 @@ static MEdge new_edge(const int v1, const int v2)
   MEdge edge;
   edge.v1 = v1;
   edge.v2 = v2;
+  edge.crease = 0;
   edge.flag = (ME_EDGEDRAW | ME_EDGERENDER);
   return edge;
 }
@@ -156,6 +157,7 @@ static MEdge new_loose_edge(const int v1, const int v2)
   MEdge edge;
   edge.v1 = v1;
   edge.v2 = v2;
+  edge.crease = 0;
   edge.flag = ME_LOOSEEDGE;
   return edge;
 }
@@ -286,6 +288,7 @@ static void extrude_mesh_vertices(Mesh &mesh,
       for (const int i : range) {
         const float3 offset = offsets[selection[i]];
         add_v3_v3(new_verts[i].co, offset);
+        new_verts[i].flag = 0;
       }
     });
   });
@@ -608,6 +611,7 @@ static void extrude_mesh_edges(Mesh &mesh,
     threading::parallel_for(new_verts.index_range(), 1024, [&](const IndexRange range) {
       for (const int i : range) {
         add_v3_v3(new_verts[i].co, offset);
+        new_verts[i].flag = 0;
       }
     });
   }
@@ -615,6 +619,7 @@ static void extrude_mesh_edges(Mesh &mesh,
     threading::parallel_for(new_verts.index_range(), 1024, [&](const IndexRange range) {
       for (const int i : range) {
         add_v3_v3(new_verts[i].co, vert_offsets[new_vert_indices[i]]);
+        new_verts[i].flag = 0;
       }
     });
   }
@@ -996,6 +1001,10 @@ static void extrude_mesh_face_regions(Mesh &mesh,
         });
   }
 
+  for (MVert &vert : verts.slice(new_vert_range)) {
+    vert.flag = 0;
+  }
+
   MutableSpan<int> vert_orig_indices = get_orig_index_layer(mesh, ATTR_DOMAIN_POINT);
   vert_orig_indices.slice(new_vert_range).fill(ORIGINDEX_NONE);
 
@@ -1253,6 +1262,7 @@ static void extrude_individual_mesh_faces(Mesh &mesh,
       const IndexRange poly_corner_range = selected_corner_range(index_offsets, i_selection);
       for (MVert &vert : new_verts.slice(poly_corner_range)) {
         add_v3_v3(vert.co, poly_offset[poly_selection[i_selection]]);
+        vert.flag = 0;
       }
     }
   });
diff --git a/source/blender/render/intern/engine.cc b/source/blender/render/intern/engine.cc
index a440b34af78..0024ebe38f7 100644
--- a/source/blender/render/intern/engine.cc
+++ b/source/blender/render/intern/engine.cc
@@ -1276,8 +1276,6 @@ void RE_engine_gpu_context_destroy(RenderEngine *engine)
     return;
   }
 
-  BLI_assert(BLI_thread_is_main());
-
   const bool drw_state = DRW_opengl_context_release();
 
   WM_opengl_context_activate(engine->gpu_context);
diff --git a/source/blender/sequencer/intern/modifier.c b/source/blender/sequencer/intern/modifier.c
index b0f2f53396b..b17db8f762e 100644
--- a/source/blender/sequencer/intern/modifier.c
+++ b/source/blender/sequencer/intern/modifier.c
@@ -598,7 +598,7 @@ static void modifier_color_balance_apply(
   ColorBalanceInitData init_data;
 
   if (!ibuf->rect_float && make_float) {
-    imb_addrectfloatImBuf(ibuf);
+    imb_addrectfloatImBuf(ibuf, 4);
   }
 
   init_data.cb = cb;
diff --git a/source/blender/sequencer/intern/render.c b/source/blender/sequencer/intern/render.c
index b7dc0e7035d..fd3b6103b94 100644
--- a/source/blender/sequencer/intern/render.c
+++ b/source/blender/sequencer/intern/render.c
@@ -134,7 +134,7 @@ void seq_imbuf_to_sequencer_space(Scene *scene, ImBuf *ibuf, bool make_float)
       /* We perform conversion to a float buffer so we don't worry about
        * precision loss.
        */
-      imb_addrectfloatImBuf(ibuf);
+      imb_addrectfloatImBuf(ibuf, 4);
       IMB_colormanagement_transform_from_byte_threaded(ibuf->rect_float,
                                                        (unsigned char *)ibuf->rect,
                                                        ibuf->x,