4 files changed, 33 insertions, 6 deletions

diff --git a/source/blender/blenkernel/BKE_customdata.h b/source/blender/blenkernel/BKE_customdata.h
index 266dc3e66f7..bc94ab8ed41 100644
--- a/source/blender/blenkernel/BKE_customdata.h
+++ b/source/blender/blenkernel/BKE_customdata.h
@@ -307,6 +307,7 @@ void CustomData_set_layer_flag(struct CustomData *data, int type, int flag);
 
 void CustomData_bmesh_set_default(struct CustomData *data, void **block);
 void CustomData_bmesh_free_block(struct CustomData *data, void **block);
+void CustomData_bmesh_free_block_data(struct CustomData *data, void **block);
 
 /* copy custom data to/from layers as in mesh/derivedmesh, to editmesh
  * blocks of data. the CustomData's must not be compatible */
diff --git a/source/blender/blenkernel/intern/customdata.c b/source/blender/blenkernel/intern/customdata.c
index 11c8ca5d3c4..0988af87589 100644
--- a/source/blender/blenkernel/intern/customdata.c
+++ b/source/blender/blenkernel/intern/customdata.c
@@ -2422,6 +2422,32 @@ void CustomData_bmesh_free_block(CustomData *data, void **block)
 	*block = NULL;
 }
 
+/**
+ * Same as #CustomData_bmesh_free_block but zero the memory rather then freeing.
+ */
+void CustomData_bmesh_free_block_data(CustomData *data, void **block)
+{
+	const LayerTypeInfo *typeInfo;
+	int i;
+
+	if (*block == NULL)
+		return;
+
+	for (i = 0; i < data->totlayer; ++i) {
+		if (!(data->layers[i].flag & CD_FLAG_NOFREE)) {
+			typeInfo = layerType_getInfo(data->layers[i].type);
+
+			if (typeInfo->free) {
+				int offset = data->layers[i].offset;
+				typeInfo->free((char *)*block + offset, 1, typeInfo->size);
+			}
+		}
+	}
+
+	if (data->totsize)
+		memset(*block, 0, data->totsize);
+}
+
 static void CustomData_bmesh_alloc_block(CustomData *data, void **block)
 {
 
diff --git a/source/blender/bmesh/intern/bmesh_construct.c b/source/blender/bmesh/intern/bmesh_construct.c
index a216e762401..55c738b04b4 100644
--- a/source/blender/bmesh/intern/bmesh_construct.c
+++ b/source/blender/bmesh/intern/bmesh_construct.c
@@ -759,7 +759,7 @@ static void bm_vert_attrs_copy(BMesh *source_mesh, BMesh *target_mesh,
 		return;
 	}
 	copy_v3_v3(target_vertex->no, source_vertex->no);
-	CustomData_bmesh_free_block(&target_mesh->vdata, &target_vertex->head.data);
+	CustomData_bmesh_free_block_data(&target_mesh->vdata, &target_vertex->head.data);
 	CustomData_bmesh_copy_data(&source_mesh->vdata, &target_mesh->vdata,
 	                           source_vertex->head.data, &target_vertex->head.data);
 }
@@ -771,7 +771,7 @@ static void bm_edge_attrs_copy(BMesh *source_mesh, BMesh *target_mesh,
 		BLI_assert(!"BMEdge: source and targer match");
 		return;
 	}
-	CustomData_bmesh_free_block(&target_mesh->edata, &target_edge->head.data);
+	CustomData_bmesh_free_block_data(&target_mesh->edata, &target_edge->head.data);
 	CustomData_bmesh_copy_data(&source_mesh->edata, &target_mesh->edata,
 	                           source_edge->head.data, &target_edge->head.data);
 }
@@ -783,7 +783,7 @@ static void bm_loop_attrs_copy(BMesh *source_mesh, BMesh *target_mesh,
 		BLI_assert(!"BMLoop: source and targer match");
 		return;
 	}
-	CustomData_bmesh_free_block(&target_mesh->ldata, &target_loop->head.data);
+	CustomData_bmesh_free_block_data(&target_mesh->ldata, &target_loop->head.data);
 	CustomData_bmesh_copy_data(&source_mesh->ldata, &target_mesh->ldata,
 	                           source_loop->head.data, &target_loop->head.data);
 }
@@ -796,7 +796,7 @@ static void bm_face_attrs_copy(BMesh *source_mesh, BMesh *target_mesh,
 		return;
 	}
 	copy_v3_v3(target_face->no, source_face->no);
-	CustomData_bmesh_free_block(&target_mesh->pdata, &target_face->head.data);
+	CustomData_bmesh_free_block_data(&target_mesh->pdata, &target_face->head.data);
 	CustomData_bmesh_copy_data(&source_mesh->pdata, &target_mesh->pdata,
 	                           source_face->head.data, &target_face->head.data);
 	target_face->mat_nr = source_face->mat_nr;
diff --git a/source/blender/bmesh/intern/bmesh_interp.c b/source/blender/bmesh/intern/bmesh_interp.c
index 290c6d9c9c8..bf7bfc1123c 100644
--- a/source/blender/bmesh/intern/bmesh_interp.c
+++ b/source/blender/bmesh/intern/bmesh_interp.c
@@ -55,7 +55,7 @@ static void bm_data_interp_from_elem(CustomData *data_layer, BMElem *ele1, BMEle
 				/* do nothing */
 			}
 			else {
-				CustomData_bmesh_free_block(data_layer, &ele_dst->head.data);
+				CustomData_bmesh_free_block_data(data_layer, &ele_dst->head.data);
 				CustomData_bmesh_copy_data(data_layer, data_layer, ele1->head.data, &ele_dst->head.data);
 			}
 		}
@@ -64,7 +64,7 @@ static void bm_data_interp_from_elem(CustomData *data_layer, BMElem *ele1, BMEle
 				/* do nothing */
 			}
 			else {
-				CustomData_bmesh_free_block(data_layer, &ele_dst->head.data);
+				CustomData_bmesh_free_block_data(data_layer, &ele_dst->head.data);
 				CustomData_bmesh_copy_data(data_layer, data_layer, ele2->head.data, &ele_dst->head.data);
 			}
 		}