WIP migrate attribute management to partial editing with 4 new features! See #1222.

New features include:

 - New clarity between null and empty string attributes
 - Attribute editing now shows appropriate UI widgets depending on data type
 - Attribute editing for enumerations now show a dropdown
 - Attribute editing is now schema sensitive

src/ifcblenderexport/blenderbim/bim/module/spatial/data.py

@@ -10,7 +10,9 @@ class Data:
         if not file:
             return
         product = file.by_id(product_id)
-        if product.ContainedInStructure:
+        if not hasattr(product, "ContainedInStructure"):
+            cls.products[product_id] = None
+        elif product.ContainedInStructure:
             structure = product.ContainedInStructure[0].RelatingStructure
             cls.products[product_id] = {"type": structure.is_a(), "Name": structure.Name, "id": int(structure.id())}
         else:

src/ifcblenderexport/blenderbim/bim/module/spatial/ui.py

@@ -11,7 +11,14 @@ class BIM_PT_spatial(Panel):
 
     @classmethod
     def poll(cls, context):
-        return bool(context.active_object.BIMObjectProperties.ifc_definition_id)
+        props = context.active_object.BIMObjectProperties
+        if not props.ifc_definition_id:
+            return False
+        if props.ifc_definition_id not in Data.products:
+            Data.load(props.ifc_definition_id)
+        if not Data.products[props.ifc_definition_id]:
+            return False
+        return True
 
     def draw(self, context):
         props = context.active_object.BIMObjectProperties
@@ -20,9 +27,6 @@ class BIM_PT_spatial(Panel):
         if props.ifc_definition_id not in Data.products:
             Data.load(props.ifc_definition_id)
 
-        if "Ifc" not in context.active_object.name:
-            return
-
         row = self.layout.row(align=True)
         name = "{}/{}".format(
             Data.products[props.ifc_definition_id]["type"], Data.products[props.ifc_definition_id]["Name"]