solidify modifier: thickness clamping helps prevent self intersections when there are small details on a larger model.

4 files changed, 70 insertions, 2 deletions

diff --git a/release/scripts/startup/bl_ui/properties_data_modifier.py b/release/scripts/startup/bl_ui/properties_data_modifier.py
index 66db1352032..b38e2a7e98c 100644
--- a/release/scripts/startup/bl_ui/properties_data_modifier.py
+++ b/release/scripts/startup/bl_ui/properties_data_modifier.py
@@ -750,6 +750,7 @@ class DATA_PT_modifiers(ModifierButtonsPanel, Panel):
 
         col = split.column()
         col.prop(md, "thickness")
+        col.prop(md, "thickness_clamp")
         col.prop_search(md, "vertex_group", ob, "vertex_groups", text="")
 
         col.label(text="Crease:")
@@ -761,6 +762,7 @@ class DATA_PT_modifiers(ModifierButtonsPanel, Panel):
         col = split.column()
 
         col.prop(md, "offset")
+        col.prop(md, "use_flip_normals")
         sub = col.column()
         sub.active = bool(md.vertex_group)
         sub.prop(md, "invert_vertex_group", text="Invert")
@@ -776,7 +778,6 @@ class DATA_PT_modifiers(ModifierButtonsPanel, Panel):
         row = row.row()
         row.active = md.use_rim
         row.prop(md, "material_offset_rim", text="Rim")
-        sub.prop(md, "use_flip_normals")
 
     def SUBSURF(self, layout, ob, md):
         layout.row().prop(md, "subdivision_type", expand=True)
diff --git a/source/blender/makesdna/DNA_modifier_types.h b/source/blender/makesdna/DNA_modifier_types.h
index 117eac0e42b..66685c131d4 100644
--- a/source/blender/makesdna/DNA_modifier_types.h
+++ b/source/blender/makesdna/DNA_modifier_types.h
@@ -744,6 +744,8 @@ typedef struct SolidifyModifierData {
 	float offset;			/* new surface offset level*/
 	float offset_fac;		/* midpoint of the offset  */
 	float offset_fac_vg;	/* factor for the minimum weight to use when vgroups are used, avoids 0.0 weights giving duplicate geometry */
+	float offset_clamp;		/* clamp offset based on surrounding geometry */
+	float pad;
 	float crease_inner;
 	float crease_outer;
 	float crease_rim;
diff --git a/source/blender/makesrna/intern/rna_modifier.c b/source/blender/makesrna/intern/rna_modifier.c
index 19333b3dbc8..fa436e30200 100644
--- a/source/blender/makesrna/intern/rna_modifier.c
+++ b/source/blender/makesrna/intern/rna_modifier.c
@@ -2648,6 +2648,13 @@ static void rna_def_modifier_solidify(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "Thickness", "Thickness of the shell");
 	RNA_def_property_update(prop, 0, "rna_Modifier_update");
 
+	prop = RNA_def_property(srna, "thickness_clamp", PROP_FLOAT, PROP_FACTOR);
+	RNA_def_property_float_sdna(prop, NULL, "offset_clamp");
+	RNA_def_property_range(prop, 0, 100.0);
+	RNA_def_property_ui_range(prop, 0, 2.0, 0.1, 4);
+	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, "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);
diff --git a/source/blender/modifiers/intern/MOD_solidify.c b/source/blender/modifiers/intern/MOD_solidify.c
index a198eaf8ca9..9cdd52f2375 100644
--- a/source/blender/modifiers/intern/MOD_solidify.c
+++ b/source/blender/modifiers/intern/MOD_solidify.c
@@ -251,7 +251,8 @@ static DerivedMesh *applyModifier(
 	const float ofs_new  = smd->offset + ofs_orig;
 	const float offset_fac_vg = smd->offset_fac_vg;
 	const float offset_fac_vg_inv = 1.0f - smd->offset_fac_vg;
-	const int do_flip = (smd->flag & MOD_SOLIDIFY_FLIP) != 0;
+	const bool do_flip = (smd->flag & MOD_SOLIDIFY_FLIP) != 0;
+	const bool do_clamp = (smd->offset_clamp != 0.0f);
 
 	/* weights */
 	MDeformVert *dvert, *dv = NULL;
@@ -423,6 +424,20 @@ static DerivedMesh *applyModifier(
 		float scalar_short;
 		float scalar_short_vgroup;
 
+		/* for clamping */
+		float *vert_lens = NULL;
+		const float offset    = fabsf(smd->offset) * smd->offset_clamp;
+		const float offset_sq = offset * offset;
+
+		if (do_clamp) {
+			vert_lens = MEM_callocN(sizeof(float) * numVerts, "vert_lens");
+			fill_vn_fl(vert_lens, numVerts, FLT_MAX);
+			for (i = 0; i < numEdges; i++) {
+				const float ed_len = len_squared_v3v3(mvert[medge[i].v1].co, mvert[medge[i].v2].co);
+				vert_lens[medge[i].v1] = min_ff(vert_lens[medge[i].v1], ed_len);
+				vert_lens[medge[i].v2] = min_ff(vert_lens[medge[i].v2], ed_len);
+			}
+		}
 
 		if (ofs_new != 0.0f) {
 			scalar_short = scalar_short_vgroup = ofs_new / 32767.0f;
@@ -435,6 +450,16 @@ static DerivedMesh *applyModifier(
 					scalar_short_vgroup = (offset_fac_vg + (scalar_short_vgroup * offset_fac_vg_inv)) * scalar_short;
 					dv++;
 				}
+				if (do_clamp) {
+					/* always reset becaise we may have set before */
+					if (dv == NULL) {
+						scalar_short_vgroup = scalar_short;
+					}
+					if (vert_lens[i] < offset_sq) {
+						float scalar = sqrtf(vert_lens[i]) / offset;
+						scalar_short_vgroup *= scalar;
+					}
+				}
 				madd_v3v3short_fl(mv->co, mv->no, scalar_short_vgroup);
 			}
 		}
@@ -450,9 +475,23 @@ static DerivedMesh *applyModifier(
 					scalar_short_vgroup = (offset_fac_vg + (scalar_short_vgroup * offset_fac_vg_inv)) * scalar_short;
 					dv++;
 				}
+				if (do_clamp) {
+					/* always reset becaise we may have set before */
+					if (dv == NULL) {
+						scalar_short_vgroup = scalar_short;
+					}
+					if (vert_lens[i] < offset_sq) {
+						float scalar = sqrtf(vert_lens[i]) / offset;
+						scalar_short_vgroup *= scalar;
+					}
+				}
 				madd_v3v3short_fl(mv->co, mv->no, scalar_short_vgroup);
 			}
 		}
+
+		if (do_clamp) {
+			MEM_freeN(vert_lens);
+		}
 	}
 	else {
 		/* make a face normal layer if not present */
@@ -540,6 +579,25 @@ static DerivedMesh *applyModifier(
 			}
 		}
 
+		if (do_clamp) {
+			float *vert_lens = MEM_callocN(sizeof(float) * numVerts, "vert_lens");
+			const float offset    = fabsf(smd->offset) * smd->offset_clamp;
+			const float offset_sq = offset * offset;
+			fill_vn_fl(vert_lens, numVerts, FLT_MAX);
+			for (i = 0; i < numEdges; i++) {
+				const float ed_len = len_squared_v3v3(mvert[medge[i].v1].co, mvert[medge[i].v2].co);
+				vert_lens[medge[i].v1] = min_ff(vert_lens[medge[i].v1], ed_len);
+				vert_lens[medge[i].v2] = min_ff(vert_lens[medge[i].v2], ed_len);
+			}
+			for (i = 0; i < numVerts; i++) {
+				if (vert_lens[i] < offset_sq) {
+					float scalar = sqrtf(vert_lens[i]) / offset;
+					vert_angles[i] *= scalar;
+				}
+			}
+			MEM_freeN(vert_lens);
+		}
+
 		if (ofs_new) {
 			mv = mvert + (((ofs_new >= ofs_orig) == do_flip) ? numVerts : 0);