Fix #3483. You can now conveniently duplicate material layers.

src/blenderbim/blenderbim/bim/module/material/__init__.py

@@ -32,9 +32,10 @@ classes = (
     operator.CopyMaterial,
     operator.DisableEditingAssignedMaterial,
     operator.DisableEditingMaterial,
-    operator.DisableEditingMaterials,
     operator.DisableEditingMaterialSetItem,
     operator.DisableEditingMaterialSetItemProfile,
+    operator.DisableEditingMaterials,
+    operator.DuplicateLayer,
     operator.EditAssignedMaterial,
     operator.EditMaterial,
     operator.EditMaterialSetItem,

src/blenderbim/blenderbim/bim/module/material/operator.py

@@ -311,7 +311,6 @@ class RemoveLayer(bpy.types.Operator, tool.Ifc.Operator):
     bl_idname = "bim.remove_layer"
     bl_label = "Remove Layer"
     bl_options = {"REGISTER", "UNDO"}
-    obj: bpy.props.StringProperty()
     layer: bpy.props.IntProperty()
 
     def _execute(self, context):
@@ -323,6 +322,21 @@ class RemoveLayer(bpy.types.Operator, tool.Ifc.Operator):
         ifcopenshell.api.run("material.remove_layer", tool.Ifc.get(), layer=layer)
 
 
+class DuplicateLayer(bpy.types.Operator, tool.Ifc.Operator):
+    bl_idname = "bim.duplicate_layer"
+    bl_label = "Duplicate Layer"
+    bl_options = {"REGISTER", "UNDO"}
+    layer: bpy.props.IntProperty()
+
+    def _execute(self, context):
+        layer = tool.Ifc.get().by_id(self.layer)
+        new_layer = ifcopenshell.util.element.copy(tool.Ifc.get(), layer)
+        for material_set in layer.ToMaterialLayerSet:
+            layers = list(material_set.MaterialLayers)
+            layers.insert(layers.index(layer), new_layer)
+            material_set.MaterialLayers = layers
+
+
 class AddListItem(bpy.types.Operator, tool.Ifc.Operator):
     bl_idname = "bim.add_list_item"
     bl_label = "Add List Item"

src/blenderbim/blenderbim/bim/module/material/ui.py

@@ -275,6 +275,8 @@ class BIM_PT_object_material(Panel):
                 op.material_set_item = set_item["id"]
             op = row.operator("bim.enable_editing_material_set_item", icon="GREASEPENCIL", text="")
             op.material_set_item = set_item["id"]
+        if ObjectMaterialData.data["set_item_name"] == "layer":
+            row.operator("bim.duplicate_layer", icon="DUPLICATE", text="").layer = set_item["id"]
         op = row.operator(f"bim.remove_{ObjectMaterialData.data['set_item_name']}", icon="X", text="")
         if ObjectMaterialData.data["material_class"] == "IfcMaterialList":
             setattr(op, "list_item_set", ObjectMaterialData.data["set"]["id"])