For some reason in the scene properties context.object returns None even if an object is active in the viewport, so ifc modifiers would randomly throw errors. AFAIK functionally they are supposed to point to the same thing, but active_object seems to be the superior one and context.object deprecated and kept for legacy reasons. Couldn't find dev quote but I'm sure I saw it at some point
Taking into account that now we have error messages if user will try to remove the last material layer which would make layer set invalid ifc.
FAILED test/bim/test_feature.py::test_remove_material_set_layer - AssertionError: Failed to run operator bpy.ops.bim.remove_layer(layer=IfcStore.get_file().by_id(93).MaterialLayers[...
FAILED test/bim/test_feature.py::test_export_ifc__with_basic_contents_and_saving_as_a_relative_path - AssertionError: Value is C:\IfcOpenShell\src\blenderbim\test\files\temp\export.ifc
1) Explicitly set empty ifc project not to load demo library - was still loading because it was using my default scene which caused errors.
2) typo in dimension check assertion message
It works exactly the same as schedules - you add some .svg file, path to it stored in ifc and you can attach it to the sheet.
UI - https://i.imgur.com/tGbCGBb.png
Still need to add some tests for references
Can be easily called with `pytest .\test\bim\test_feature.py -k "issue"`
Commented some lines out to make sure it doesn't interrupt someone's test process.
Need to uncomment `When I press "bim.create_drawing"` if you want to see if it freezes for you.
You can also uncomment `And I save sample test files and open in blender` to see the freeze manually in Blender client.
Before that commit if you created those types of annotations and then reopened .ifc file (without .blend) then you would lose their z coordinate and therefore would lose their value (because they were created previously as 2d annotations).
Now those annotations created as 3d to avoid that problem. I've also added temporary fallback that will turn your existing annotations to 3d next time you edit them.
Bug appeared after 046940f but it was there before - it was just kind of compensated by the other bug.
Because of that bug blender text size value was reupdated before saving it to pset therefore pset never received a new value.
Also added some refactor, planned to write some test to get this error covered.
Now shading styles are stored in ifc. It's actually stored in json file (by default it's in projects "assets/shading_styles.json") and the path to it saved in `EPset_Drawing.ShadingStyles`.
Current shading styles is stored in `EPset_Drawing.CurrentShadingStyle`.
This change could potentially cause problems but I've added some temporary fallback to make sure `EPset_Drawing.ShadingStyles` will be set to some default path and default shading styles will be copied to the project's folder.
Dion Moult
