Solidify Modifier: support non-manifold input

This adds a new mode to solidify to support non-manifold geometry
with edges using 3 or more faces as input, resulting in a manifold mesh.

Since the differences between these methods don't translate well
into short terms, they're named "Simple" and "Complex" in the UI.

This also adds clamp with respect to angles
to the existing solidify modifier calculation.

1 files changed, 75 insertions, 3 deletions

diff --git a/source/blender/makesrna/intern/rna_modifier.c b/source/blender/makesrna/intern/rna_modifier.c
index 2a125625681..6e81b1343f5 100644
--- a/source/blender/makesrna/intern/rna_modifier.c
+++ b/source/blender/makesrna/intern/rna_modifier.c
@@ -4059,16 +4059,71 @@ static void rna_def_modifier_surface(BlenderRNA *brna)
 
 static void rna_def_modifier_solidify(BlenderRNA *brna)
 {
+  static const EnumPropertyItem mode_items[] = {
+      {MOD_SOLIDIFY_MODE_EXTRUDE,
+       "EXTRUDE",
+       0,
+       "Simple",
+       "Output a solidified version of a mesh by simple extrusion"},
+      {MOD_SOLIDIFY_MODE_NONMANIFOLD,
+       "NON_MANIFOLD",
+       0,
+       "Complex",
+       "Output a manifold mesh even if the base mesh is non-manifold, "
+       "where edges have 3 or more connecting faces."
+       "This method is slower"},
+      {0, NULL, 0, NULL, NULL},
+  };
+
+  static const EnumPropertyItem nonmanifold_thickness_mode_items[] = {
+      {MOD_SOLIDIFY_NONMANIFOLD_OFFSET_MODE_FIXED,
+       "FIXED",
+       0,
+       "Fixed",
+       "Most basic thickness calculation"},
+      {MOD_SOLIDIFY_NONMANIFOLD_OFFSET_MODE_EVEN,
+       "EVEN",
+       0,
+       "Even",
+       "Even thickness calculation which takes the angle between faces into account"},
+      {MOD_SOLIDIFY_NONMANIFOLD_OFFSET_MODE_CONSTRAINTS,
+       "CONSTRAINTS",
+       0,
+       "Constraints",
+       "Thickness calculation using constraints, most advanced"},
+      {0, NULL, 0, NULL, NULL},
+  };
+
+  static const EnumPropertyItem nonmanifold_boundary_mode_items[] = {
+      {MOD_SOLIDIFY_NONMANIFOLD_BOUNDARY_MODE_NONE, "NONE", 0, "None", "No shape correction"},
+      {MOD_SOLIDIFY_NONMANIFOLD_BOUNDARY_MODE_ROUND,
+       "ROUND",
+       0,
+       "Round",
+       "Round open perimeter shape"},
+      {MOD_SOLIDIFY_NONMANIFOLD_BOUNDARY_MODE_FLAT,
+       "FLAT",
+       0,
+       "Flat",
+       "Flat open perimeter shape"},
+      {0, NULL, 0, NULL, NULL},
+  };
+
   StructRNA *srna;
   PropertyRNA *prop;
 
   srna = RNA_def_struct(brna, "SolidifyModifier", "Modifier");
-  RNA_def_struct_ui_text(srna,
-                         "Solidify Modifier",
-                         "Create a solid skin by extruding, compensating for sharp angles");
+  RNA_def_struct_ui_text(
+      srna, "Solidify Modifier", "Create a solid skin, compensating for sharp angles");
   RNA_def_struct_sdna(srna, "SolidifyModifierData");
   RNA_def_struct_ui_icon(srna, ICON_MOD_SOLIDIFY);
 
+  prop = RNA_def_property(srna, "solidify_mode", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_sdna(prop, NULL, "mode");
+  RNA_def_property_enum_items(prop, mode_items);
+  RNA_def_property_ui_text(prop, "Mode", "Selects the used algorithm");
+  RNA_def_property_update(prop, 0, "rna_Modifier_update");
+
   prop = RNA_def_property(srna, "thickness", PROP_FLOAT, PROP_DISTANCE);
   RNA_def_property_float_sdna(prop, NULL, "offset");
   RNA_def_property_range(prop, -FLT_MAX, FLT_MAX);
@@ -4083,6 +4138,11 @@ static void rna_def_modifier_solidify(BlenderRNA *brna)
   RNA_def_property_ui_text(prop, "Clamp", "Offset clamp based on geometry scale");
   RNA_def_property_update(prop, 0, "rna_Modifier_update");
 
+  prop = RNA_def_property(srna, "use_thickness_angle_clamp", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "flag", MOD_SOLIDIFY_OFFSET_ANGLE_CLAMP);
+  RNA_def_property_ui_text(prop, "Angle Clamp", "Clamp thickness based on angles");
+  RNA_def_property_update(prop, 0, "rna_Modifier_update");
+
   prop = RNA_def_property(srna, "thickness_vertex_group", PROP_FLOAT, PROP_FACTOR);
   RNA_def_property_float_sdna(prop, NULL, "offset_fac_vg");
   RNA_def_property_range(prop, 0.0, 1.0);
@@ -4176,6 +4236,18 @@ static void rna_def_modifier_solidify(BlenderRNA *brna)
   RNA_def_property_boolean_sdna(prop, NULL, "flag", MOD_SOLIDIFY_NOSHELL);
   RNA_def_property_ui_text(prop, "Only Rim", "Only add the rim to the original data");
   RNA_def_property_update(prop, 0, "rna_Modifier_update");
+
+  /* Settings for #MOD_SOLIDIFY_MODE_NONMANIFOLD */
+  prop = RNA_def_property(srna, "nonmanifold_thickness_mode", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_sdna(prop, NULL, "nonmanifold_offset_mode");
+  RNA_def_property_enum_items(prop, nonmanifold_thickness_mode_items);
+  RNA_def_property_ui_text(prop, "Thickness Mode", "Selects the used thickness algorithm");
+  RNA_def_property_update(prop, 0, "rna_Modifier_update");
+
+  prop = RNA_def_property(srna, "nonmanifold_boundary_mode", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_items(prop, nonmanifold_boundary_mode_items);
+  RNA_def_property_ui_text(prop, "Boundary Shape", "Selects the boundary adjustment algorithm");
+  RNA_def_property_update(prop, 0, "rna_Modifier_update");
 }
 
 static void rna_def_modifier_screw(BlenderRNA *brna)