Fix #3169. Don't allow the user to create invalid material sets without items.

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

@@ -96,6 +96,7 @@ class ObjectMaterialData:
         cls.data["total_thickness"] = cls.total_thickness()
         cls.data["materials"] = cls.materials()
         cls.data["type_material"] = cls.type_material()
+        cls.data["material_type"] = cls.material_type()
         cls.is_loaded = True
 
     @classmethod
@@ -244,3 +245,17 @@ class ObjectMaterialData:
             else:
                 name_attr = "Name"
             return getattr(material, name_attr, "Unnamed") or "Unnamed"
+
+    @classmethod
+    def material_type(cls):
+        material_types = [
+            "IfcMaterial",
+            "IfcMaterialConstituentSet",
+            "IfcMaterialLayerSet",
+            "IfcMaterialProfileSet",
+            "IfcMaterialList",
+        ]
+        version = tool.Ifc.get_schema()
+        if version == "IFC2X3":
+            material_types = ["IfcMaterial", "IfcMaterialLayerSet", "IfcMaterialList"]
+        return [(m, m, ifcopenshell.util.doc.get_entity_doc(version, m).get("description", "")) for m in material_types]

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

@@ -189,23 +189,25 @@ class AssignMaterial(bpy.types.Operator, tool.Ifc.Operator):
                 material=material,
             )
             assigned_material = ifcopenshell.util.element.get_material(element)
-            if assigned_material.is_a() in ("IfcMaterialLayerSet", "IfcMaterialLayerSetUsage"):
+            if assigned_material.is_a("IfcMaterialConstituentSet"):
-                if assigned_material.is_a("IfcMaterialLayerSet"):
+                if not assigned_material.MaterialConstituents:
-                    layer_set = assigned_material
+                    ifcopenshell.api.run(
-                else:
+                        "material.add_constituent",
-                    layer_set = assigned_material.ForLayerSet
+                        tool.Ifc.get(),
-
+                        constituent_set=assigned_material,
-                if not layer_set.MaterialLayers:
+                        material=material,
+                    )
+            elif assigned_material.is_a() == "IfcMaterialLayerSet":
+                if not assigned_material.MaterialLayers:
                     unit_scale = ifcopenshell.util.unit.calculate_unit_scale(tool.Ifc.get())
                     layer = ifcopenshell.api.run(
                         "material.add_layer",
                         tool.Ifc.get(),
-                        layer_set=layer_set,
+                        layer_set=assigned_material,
                         material=material,
                     )
                     thickness = 0.1  # Arbitrary metric thickness for now
                     layer.LayerThickness = thickness / unit_scale
-
             elif assigned_material.is_a("IfcMaterialProfileSet"):
                 if not assigned_material.MaterialProfiles:
                     named_profiles = [p for p in tool.Ifc.get().by_type("IfcProfileDef") if p.ProfileName]
@@ -279,12 +281,12 @@ class RemoveConstituent(bpy.types.Operator, tool.Ifc.Operator):
     constituent: bpy.props.IntProperty()
 
     def _execute(self, context):
-        for inverse in tool.Ifc.get().get_inverse(tool.Ifc.get().by_id(self.constituent)):
+        constituent = tool.Ifc.get().by_id(self.constituent)
-            if inverse.is_a("IfcMaterialConstituentSet") and len(inverse.MaterialConstituents) == 1:
+        for material_set in layer.ToMaterialConstituentSet:
-                return
+            if len(material_set.MaterialConstituents) == 1:
-        ifcopenshell.api.run(
+                self.report({"ERROR"}, "At least one constituent must exist")
-            "material.remove_constituent", tool.Ifc.get(), constituent=tool.Ifc.get().by_id(self.constituent)
+                return {"ERROR"}
-        )
+        ifcopenshell.api.run("material.remove_constituent", tool.Ifc.get(), constituent=constituent)
 
 
 class AddProfile(bpy.types.Operator, tool.Ifc.Operator):
@@ -314,10 +316,12 @@ class RemoveProfile(bpy.types.Operator, tool.Ifc.Operator):
     profile: bpy.props.IntProperty()
 
     def _execute(self, context):
-        for inverse in tool.Ifc.get().get_inverse(tool.Ifc.get().by_id(self.profile)):
+        profile = tool.Ifc.get().by_id(self.profile)
-            if inverse.is_a("IfcMaterialProfileSet") and len(inverse.MaterialProfiles) == 1:
+        for material_set in profile.ToMaterialProfileSet:
-                return
+            if len(material_set.MaterialProfiles) == 1:
-        ifcopenshell.api.run("material.remove_profile", tool.Ifc.get(), profile=tool.Ifc.get().by_id(self.profile))
+                self.report({"ERROR"}, "At least one profile must exist")
+                return {"ERROR"}
+        ifcopenshell.api.run("material.remove_profile", tool.Ifc.get(), profile=profile)
 
 
 class AddLayer(bpy.types.Operator, tool.Ifc.Operator):
@@ -340,7 +344,7 @@ class AddLayer(bpy.types.Operator, tool.Ifc.Operator):
         )
 
         unit_scale = ifcopenshell.util.unit.calculate_unit_scale(tool.Ifc.get())
-        thickness = 0.1 # Arbitrary metric thickness for now
+        thickness = 0.1  # Arbitrary metric thickness for now
         layer.LayerThickness = thickness / unit_scale
 
 
@@ -376,13 +380,12 @@ class RemoveLayer(bpy.types.Operator, tool.Ifc.Operator):
     layer: bpy.props.IntProperty()
 
     def _execute(self, context):
-        for inverse in tool.Ifc.get().get_inverse(tool.Ifc.get().by_id(self.layer)):
+        layer = tool.Ifc.get().by_id(self.layer)
-            if inverse.is_a("IfcMaterialLayerSet") and len(inverse.MaterialLayers) == 1:
+        for material_set in layer.ToMaterialLayerSet:
-                self.report(
+            if len(material_set.MaterialLayers) == 1:
-                    {"ERROR"}, "Cannot remove material layer - IfcMaterialLayerSet should alawys have atleast 1 layer"
+                self.report({"ERROR"}, "At least one layer must exist")
-                )
                 return {"ERROR"}
-        ifcopenshell.api.run("material.remove_layer", tool.Ifc.get(), layer=tool.Ifc.get().by_id(self.layer))
+        ifcopenshell.api.run("material.remove_layer", tool.Ifc.get(), layer=layer)
 
 
 class AddListItem(bpy.types.Operator, tool.Ifc.Operator):

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

@@ -85,24 +85,10 @@ def get_materials(self, context):
     return ObjectMaterialData.data["materials"]
 
 
-def get_object_material_types(self, context):
+def get_object_material_type(self, context):
-    global materialtypes_enum
+    if not ObjectMaterialData.is_loaded:
-    if len(materialtypes_enum) == 0 and IfcStore.get_file():
+        ObjectMaterialData.load()
-        material_types = [
+    return ObjectMaterialData.data["material_type"]
-            "IfcMaterial",
-            "IfcMaterialConstituentSet",
-            "IfcMaterialLayerSet",
-            "IfcMaterialLayerSetUsage",
-            "IfcMaterialProfileSet",
-            "IfcMaterialProfileSetUsage",
-            "IfcMaterialList",
-        ]
-        version = tool.Ifc.get_schema()
-        if version == "IFC2X3":
-            material_types = ["IfcMaterial", "IfcMaterialLayerSet", "IfcMaterialLayerSetUsage", "IfcMaterialList"]
-        materialtypes_enum.clear()
-        materialtypes_enum = [(m, m, get_entity_doc(version, m).get("description", "")) for m in material_types]
-    return materialtypes_enum
 
 
 def get_material_types(self, context):
@@ -137,7 +123,7 @@ class BIMMaterialProperties(PropertyGroup):
 
 
 class BIMObjectMaterialProperties(PropertyGroup):
-    material_type: EnumProperty(items=get_object_material_types, name="Material Type")
+    material_type: EnumProperty(items=get_object_material_type, name="Material Type")
     material: EnumProperty(items=get_materials, name="Material")
     is_editing: BoolProperty(name="Is Editing", default=False)
     material_set_usage_attributes: CollectionProperty(name="Material Set Usage Attributes", type=Attribute)

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

@@ -155,13 +155,7 @@ class BIM_PT_object_material(Panel):
 
         row = self.layout.row(align=True)
         prop_with_search(row, self.props, "material_type", text="")
-        if self.props.material_type in (
+        prop_with_search(row, self.props, "material", text="")
-            "IfcMaterial",
-            "IfcMaterialList",
-            "IfcMaterialLayerSet",
-            "IfcMaterialLayerSetUsage",
-        ):
-            prop_with_search(row, self.props, "material", text="")
         row.operator("bim.assign_material", icon="ADD", text="")
 
     def draw_material_ui(self):