Fix [#37266] Skin modifier can't be copied.

Patch by Martin Felke, many thanks.

When copying that modifier across objects, we also have to ensure that a skin CDLayer is present in dest objects (just as when adding it).

3 files changed, 8 insertions, 3 deletions

diff --git a/source/blender/blenkernel/BKE_modifier.h b/source/blender/blenkernel/BKE_modifier.h
index 6bf42a3e885..65038c7f09c 100644
--- a/source/blender/blenkernel/BKE_modifier.h
+++ b/source/blender/blenkernel/BKE_modifier.h
@@ -357,6 +357,7 @@ bool          modifiers_usesArmature(struct Object *ob, struct bArmature *arm);
 bool          modifiers_isCorrectableDeformed(struct Scene *scene, struct Object *ob);
 void          modifier_freeTemporaryData(struct ModifierData *md);
 bool          modifiers_isPreview(struct Object *ob);
+void          modifier_skin_customdata_ensure(struct Object *ob);
 
 typedef struct CDMaskLink {
 	struct CDMaskLink *next;
diff --git a/source/blender/blenkernel/intern/object.c b/source/blender/blenkernel/intern/object.c
index bef0263b2f5..45d9d144f55 100644
--- a/source/blender/blenkernel/intern/object.c
+++ b/source/blender/blenkernel/intern/object.c
@@ -32,7 +32,7 @@
 
 #include <string.h>
 #include <math.h>
-#include <stdio.h>			
+#include <stdio.h>
 
 #include "MEM_guardedalloc.h"
 
@@ -256,6 +256,11 @@ void BKE_object_link_modifiers(struct Object *ob_dst, struct Object *ob_src)
 
 		if (!BKE_object_support_modifier_type_check(ob_dst, md->type))
 			continue;
+		
+		if (md->type == eModifierType_Skin) {
+			/* ensure skin-node customdata exists */
+			modifier_skin_customdata_ensure(ob_dst);
+		}
 
 		nmd = modifier_new(md->type);
 		BLI_strncpy(nmd->name, md->name, sizeof(nmd->name));
diff --git a/source/blender/editors/object/object_modifier.c b/source/blender/editors/object/object_modifier.c
index 0ba84e27420..ec0423d7480 100644
--- a/source/blender/editors/object/object_modifier.c
+++ b/source/blender/editors/object/object_modifier.c
@@ -87,7 +87,6 @@
 
 #include "object_intern.h"
 
-static void modifier_skin_customdata_ensure(struct Object *ob);
 static void modifier_skin_customdata_delete(struct Object *ob);
 
 /******************************** API ****************************/
@@ -1434,7 +1433,7 @@ void OBJECT_OT_multires_base_apply(wmOperatorType *ot)
 
 /************************** skin modifier ***********************/
 
-static void modifier_skin_customdata_ensure(Object *ob)
+void modifier_skin_customdata_ensure(Object *ob)
 {
 	Mesh *me = ob->data;
 	BMesh *bm = me->edit_btmesh ? me->edit_btmesh->bm : NULL;