Fixed ifc window bugs

1) The bug occured if you would try to remove ifc window modifier and add it back again. Now adding new window checks if window was previously added
2) Second bug occured if you import .ifc project with window and some props were not used before (for example window was without transom), then newly added props would have incorrect units.

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

@@ -339,6 +339,7 @@ class BIMWindowProperties(PropertyGroup):
         "TRIPLE_PANEL_VERTICAL":   (3, ((200, 400), (0,   0  ))),
     }
 
+    window_added_previously: bpy.props.BoolProperty(default=False)
     is_editing: bpy.props.IntProperty(default=-1)
     window_type: bpy.props.EnumProperty(
         name="Window Type", items=window_types, default="SINGLE_PANEL", update=window_type_prop_update

src/blenderbim/blenderbim/bim/module/model/window.py

@@ -370,16 +370,18 @@ class AddWindow(bpy.types.Operator, tool.Ifc.Operator):
         element = tool.Ifc.get_entity(obj)
         props = obj.BIMWindowProperties
 
-        si_coversion = 0.001 / ifcopenshell.util.unit.calculate_unit_scale(tool.Ifc.get())
-        for prop_name in props.bl_rna.properties.keys():
-            if prop_name in ("rna_type", "name", "is_editing", "window_type"):
-                continue
-            prop_value = getattr(props, prop_name)
-            if type(prop_value) is float:
-                prop_value = prop_value * si_coversion
-            elif type(prop_value) is bpy.types.bpy_prop_array:
-                prop_value = [el * si_coversion for el in prop_value]
-            setattr(props, prop_name, prop_value)
+        # need to make sure all default props will have correct units
+        si_conversion = 0.001 / ifcopenshell.util.unit.calculate_unit_scale(tool.Ifc.get())
+        if not props.window_added_previously:
+            for prop_name in props.bl_rna.properties.keys():
+                if prop_name in ("rna_type", "name", "is_editing", "window_type", "window_added_previously"):
+                    continue
+                prop_value = getattr(props, prop_name)
+                if type(prop_value) is float:
+                    prop_value = prop_value * si_conversion
+                elif type(prop_value) is bpy.types.bpy_prop_array:
+                    prop_value = [el * si_conversion for el in prop_value]
+                setattr(props, prop_name, prop_value)
 
         window_data = props.get_general_kwargs()
         lining_props = props.get_lining_kwargs()
@@ -470,10 +472,24 @@ class EnableEditingWindow(bpy.types.Operator, tool.Ifc.Operator):
         element = tool.Ifc.get_entity(obj)
         pset = ifcopenshell.util.element.get_psets(element)
         data = json.loads(pset["BBIM_Window"]["Data"])
+        data.update(data.pop("lining_properties"))
+        data.update(data.pop("panel_properties"))
+
         # required since we could load pset from .ifc and BIMWindowProperties won't be set
         for prop_name in data:
             setattr(props, prop_name, data[prop_name])
-
+        
+        # need to make sure all props that weren't used before
+        # will have correct units
+        si_conversion = 0.001 / ifcopenshell.util.unit.calculate_unit_scale(tool.Ifc.get())
+        props_bl_rna = props.bl_rna.properties
+        for prop_name in props_bl_rna.keys():
+            if prop_name in data:
+                continue
+            if prop_name in ("rna_type", "name", "is_editing", "window_added_previously"):
+                continue
+            setattr(props, prop_name, props_bl_rna[prop_name].default*si_conversion)
+            
         props.is_editing = 1
         return {"FINISHED"}
 
@@ -485,12 +501,14 @@ class RemoveWindow(bpy.types.Operator, tool.Ifc.Operator):
 
     def _execute(self, context):
         obj = context.active_object
+        props = obj.BIMWindowProperties
         element = tool.Ifc.get_entity(obj)
         obj.BIMWindowProperties.is_editing = -1
 
         pset = ifcopenshell.util.element.get_psets(element)
         pset = tool.Ifc.get().by_id(pset["BBIM_Window"]["id"])
         ifcopenshell.api.run("pset.remove_pset", tool.Ifc.get(), pset=pset)
+        props.window_added_previously = True
 
         return {"FINISHED"}