bim.merge_identical_objects to support merging IfcMaterials

src/bonsai/bonsai/bim/module/debug/operator.py

@@ -691,6 +691,7 @@ class PurgeUnusedObjects(bpy.types.Operator, tool.Ifc.Operator):
 class MergeIdenticalObjects(bpy.types.Operator, tool.Ifc.Operator):
     bl_idname = "bim.merge_identical_objects"
     bl_label = "Merge Identical Objects"
+    bl_description = "For materials currently only IfcMaterials are supported"
     bl_options = {"REGISTER", "UNDO"}
 
     object_type: bpy.props.EnumProperty(
@@ -704,20 +705,21 @@ class MergeIdenticalObjects(bpy.types.Operator, tool.Ifc.Operator):
     )
 
     def _execute(self, context):
-        object_type = self.object_type
-        if object_type == "STYLE":
-            merged_data = tool.Debug.merge_identical_objects("style")
-            if merged_data:
-                print("Merged styles:")
-                for style_type, style_names in merged_data.items():
-                    print(f"- {style_type}: {', '.join(style_names)}")
-            merged = sum(len(v) for v in merged_data.values())
+        object_type: str = self.object_type
+        if object_type in ("STYLE", "MATERIAL"):
+            merged_data = tool.Debug.merge_identical_objects(object_type)
         else:
             self.report({"ERROR"}, f"Invalid object type {object_type}.")
             return {"CANCELLED"}
+        plural_object_type = f"{object_type.lower()}s"
+        if merged_data:
+            print(f"Merged {plural_object_type}:")
+            for element_type, element_names in merged_data.items():
+                print(f"- {element_type}: {', '.join(element_names)}")
+        merged = sum(len(v) for v in merged_data.values())
 
         msg = " See system console for details." if merged else ""
-        self.report({"INFO"}, f"{merged} identical {object_type.lower()}s were merged.{msg}")
+        self.report({"INFO"}, f"{merged} identical {plural_object_type} were merged.{msg}")
 
         if merged == 0:
             return

src/bonsai/bonsai/bim/module/project/ui.py

@@ -524,7 +524,10 @@ class BIM_PT_purge(Panel):
         layout = self.layout
         layout.operator("bim.purge_unused_objects", text="Purge Unused Profiles").object_type = "PROFILE"
         layout.operator("bim.purge_unused_objects", text="Purge Unused Types").object_type = "TYPE"
-        layout.operator("bim.purge_unused_objects", text="Purge Unused Materials").object_type = "MATERIAL"
+        row = layout.row(align=True)
+        row.label(text="Materials: ")
+        row.operator("bim.purge_unused_objects", text="Purge Unused").object_type = "MATERIAL"
+        row.operator("bim.merge_identical_objects", text="Merge Identical").object_type = "MATERIAL"
         row = layout.row(align=True)
         row.label(text="Styles: ")
         row.operator("bim.purge_unused_objects", text="Purge Unused").object_type = "STYLE"

src/bonsai/bonsai/tool/debug.py

@@ -19,6 +19,7 @@
 import os
 import json
 import bpy
+import ifcopenshell.api.material
 import ifcopenshell.express
 import ifcopenshell.express.schema
 import ifcopenshell.express.schema_class
@@ -104,7 +105,7 @@ class Debug(bonsai.core.tool.Debug):
         return sum(unused.values())
 
     @classmethod
-    def merge_identical_objects(cls, object_type: Literal["style"]) -> dict[str, list[str]]:
+    def merge_identical_objects(cls, object_type: Literal["STYLE", "MATERIAL"]) -> dict[str, list[str]]:
         """Merge identical objects.
 
         Note that Styles UI (or other UI) should be updated manually after using this method.
@@ -115,31 +116,35 @@ class Debug(bonsai.core.tool.Debug):
             return hash(json.dumps(element.get_info(include_identifier=False, recursive=True), sort_keys=True))
 
         ifc_file = tool.Ifc.get()
+        merged_element_types: dict[str, list[str]] = {}
 
-        if object_type == "style":
+        if object_type == "STYLE":
             declaration = tool.Ifc.schema().declaration_by_name("IfcPresentationStyle")
-            merged_element_types: dict[str, list[str]] = {}
             element_types = [e.name() for e in ifcopenshell.util.schema.get_subtypes(declaration)]
+        elif object_type == "MATERIAL":
+            # TODO: support other material types.
+            element_types = ["IfcMaterial"]
+
         for element_type in element_types:
-            elements = ifc_file.by_type(element_type)
+            elements = ifc_file.by_type(element_type, include_subtypes=False)
 
             # Calculate hashes.
             hash_to_elements: defaultdict[int, list[ifcopenshell.entity_instance]] = defaultdict(list)
             for element in elements:
-                # Ignore unnamed styles as they may be not safe to merge.
+                # Ignore unnamed elements as they may be not safe to merge.
                 if not element.Name:
                     continue
                 element_hash = get_hash(element)
                 hash_to_elements[element_hash].append(element)
 
             merged_elements_names: list[str] = []
-            # Merge styles.
+            # Merge elements.
             for elements in hash_to_elements.values():
                 if len(elements) == 1:
                     continue
 
                 main_element = elements[0]
-                if object_type == "style":
+                if object_type == "STYLE":
                     main_style_obj = tool.Ifc.get_object(main_element)
                     for style in elements[1:]:
                         ifcopenshell.util.element.replace_element(style, main_element)
@@ -151,6 +156,12 @@ class Debug(bonsai.core.tool.Debug):
                         merged_elements_names.append(style.Name)
                         bonsai.core.style.remove_style(tool.Ifc, tool.Style, style, reload_styles_ui=False)
 
+                elif object_type == "MATERIAL":
+                    for material in elements[1:]:
+                        ifcopenshell.util.element.replace_element(material, main_element)
+                        merged_elements_names.append(material.Name)
+                        ifcopenshell.api.material.remove_material(ifc_file, material)
+
             if merged_elements_names:
                 merged_element_types[element_type] = merged_elements_names
         return merged_element_types

src/bonsai/test/tool/test_debug.py

@@ -19,6 +19,7 @@
 import os
 import bpy
 import ifcopenshell
+import ifcopenshell.api.style
 import ifcopenshell.util.schema
 import bonsai.core.tool
 import bonsai.tool as tool
@@ -85,5 +86,21 @@ class TestMergeIdenticalObject(NewFile):
                 for style in ifc.by_type(style_type):
                     style.FillStyles = (ifc.create_entity("IfcFillAreaStyleHatching"),)
 
-        merge_data = subject.merge_identical_objects("style")
+        merge_data = subject.merge_identical_objects("STYLE")
         assert merge_data == {style_type: [style_type] for style_type in style_types}
+
+    def test_merge_identical_materials(self):
+        tool.Ifc.set(ifc := ifcopenshell.file())
+        context = ifc.create_entity("IfcGeometricRepresentationContext")
+        style = ifc.create_entity("IfcSurfaceStyle")
+        element_types = ["IfcMaterial"]
+        for element_type in element_types:
+            ifc.create_entity(element_type, Name=element_type, Category="Category")
+            ifc.create_entity(element_type, Name=element_type, Category="Category")
+            ifc.create_entity(element_type, Name="NotToMerge", Category="Category")
+
+            for material in ifc.by_type(element_type):
+                ifcopenshell.api.style.assign_material_style(ifc, material, style, context)
+
+        merge_data = subject.merge_identical_objects("MATERIAL")
+        assert merge_data == {element_type: [element_type] for element_type in element_types}