New import workaround for vendors who create a silly amount of materials like DDS-CAD

src/ifcblenderexport/blenderbim/bim/import_ifc.py

@@ -63,10 +63,9 @@ class MaterialCreator():
             self.parse_styled_item(styled_item, self.materials[material_name])
 
         if self.ifc_import_settings.should_treat_styled_item_as_material:
-            # Revit workaround: since Revit exports all material
+            # Revit workaround: since Revit/DDS-CAD exports all material
-            # assignments as individual object styled items. Treating
+            # assignments as individual object styled items. Treating them as
-            # them as reusable materials makes things much more
+            # reusable materials makes things much more efficient in Blender.
-            # efficient in Blender.
             self.assign_material_to_mesh(self.materials[material_name])
         else:
             # Proper behaviour
@@ -233,10 +232,16 @@ class IfcImporter():
             self.merge_by_class()
         elif self.ifc_import_settings.should_merge_by_material:
             self.merge_by_material()
+        if self.ifc_import_settings.should_merge_materials_by_colour \
+                or (self.ifc_import_settings.should_auto_set_workarounds \
+                    and len(self.material_creator.materials) > 300):
+            self.merge_materials_by_colour()
         if self.ifc_import_settings.should_clean_mesh:
             self.clean_mesh()
 
     def auto_set_workarounds(self):
+        if 'DDS-CAD' in self.file.wrapped_data.header.file_name.originating_system:
+            self.ifc_import_settings.should_treat_styled_item_as_material = True
         applications = self.file.by_type('IfcApplication')
         if not applications:
             return
@@ -517,6 +522,28 @@ class IfcImporter():
             context_override['selected_objects'] = context_override['selected_editable_objects'] = objs
             bpy.ops.object.join(context_override)
 
+    def merge_materials_by_colour(self):
+        cleaned_materials = {}
+        for m in bpy.data.materials:
+            key = '-'.join([str(x) for x in m.diffuse_color])
+            cleaned_materials[key] = { 'diffuse_color': m.diffuse_color }
+
+        for cleaned_material in cleaned_materials.values():
+            cleaned_material['material'] = bpy.data.materials.new('Merged Material')
+            cleaned_material['material'].diffuse_color = cleaned_material['diffuse_color']
+
+        for obj in self.added_data.values():
+            if not hasattr(obj, 'material_slots') \
+                    or not obj.material_slots:
+                continue
+            for slot in obj.material_slots:
+                m = slot.material
+                key = '-'.join([str(x) for x in m.diffuse_color])
+                slot.material = cleaned_materials[key]['material']
+
+        for material in self.material_creator.materials.values():
+            bpy.data.materials.remove(material)
+
     def clean_mesh(self):
         obj = None
         last_obj = None
@@ -960,6 +987,7 @@ class IfcImportSettings:
         self.should_ignore_site_coordinates = False
         self.should_ignore_building_coordinates = False
         self.should_reset_absolute_coordinates = False
+        self.should_merge_materials_by_colour = False
         self.should_import_curves = False
         self.should_import_opening_elements = False
         self.should_import_spaces = False

src/ifcblenderexport/blenderbim/bim/operator.py

@@ -94,6 +94,7 @@ class ImportIFC(bpy.types.Operator, ImportHelper):
         ifc_import_settings.should_import_aggregates = bpy.context.scene.BIMProperties.import_should_import_aggregates
         ifc_import_settings.should_merge_by_class = bpy.context.scene.BIMProperties.import_should_merge_by_class
         ifc_import_settings.should_merge_by_material = bpy.context.scene.BIMProperties.import_should_merge_by_material
+        ifc_import_settings.should_merge_materials_by_colour = bpy.context.scene.BIMProperties.import_should_merge_materials_by_colour
         ifc_import_settings.should_clean_mesh = bpy.context.scene.BIMProperties.import_should_clean_mesh
         ifc_importer = import_ifc.IfcImporter(ifc_import_settings)
         ifc_importer.execute()

src/ifcblenderexport/blenderbim/bim/prop.py

@@ -813,6 +813,7 @@ class BIMProperties(PropertyGroup):
     import_should_import_aggregates: BoolProperty(name="Import Aggregates", default=True)
     import_should_merge_by_class: BoolProperty(name="Import and Merge by Class", default=False)
     import_should_merge_by_material: BoolProperty(name="Import and Merge by Material", default=False)
+    import_should_merge_materials_by_colour: BoolProperty(name="Import and Merge Materials by Colour", default=False)
     import_should_clean_mesh: BoolProperty(name="Import and Clean Mesh", default=True)
     qa_reject_element_reason: StringProperty(name="Element Rejection Reason")
     person: EnumProperty(items=getPersons, name="Person")

src/ifcblenderexport/blenderbim/bim/ui.py

@@ -940,6 +940,8 @@ class BIM_PT_mvd(Panel):
         row = layout.row()
         row.prop(bim_properties, 'import_should_merge_by_material')
         row = layout.row()
+        row.prop(bim_properties, 'import_should_merge_materials_by_colour')
+        row = layout.row()
         row.prop(bim_properties, 'import_should_clean_mesh')
 
         layout.label(text='Vendor Workarounds:')

src/ifcblenderexport/material_cleaner.py

@@ -1,34 +0,0 @@
-import bpy
-import pprint
-print('# Start')
-cleaned_materials = {}
-n = 0
-for m in bpy.data.materials:
-    r = m.diffuse_color[0]
-    g = m.diffuse_color[1]
-    b = m.diffuse_color[2]
-    key = str(r) + '-' + str(g) + '-' + str(b)
-    cleaned_materials[key] = {'name': 'name{}'.format(n)}
-    n += 1
-
-pprint.pprint(cleaned_materials)
-print(len(bpy.data.materials.keys()))
-print(len(cleaned_materials.keys()))
-
-for rgb, data in cleaned_materials.items():
-    m = bpy.data.materials.new(data['name'])
-    print(rgb)
-    m.diffuse_color = (
-        float(rgb.split('-')[0]),
-        float(rgb.split('-')[1]),
-        float(rgb.split('-')[2]),
-        1)
-    data['material'] = m
-        
-for o in bpy.context.selected_objects:
-    m = o.material_slots[0].material
-    r = m.diffuse_color[0]
-    g = m.diffuse_color[1]
-    b = m.diffuse_color[2]
-    key = str(r) + '-' + str(g) + '-' + str(b)
-    o.material_slots[0].material = cleaned_materials[key]['material']