Currently, the undo system works by wrapping the execute operator. What was not considered was that execute() isn't the only entry point to operators. Operators can be invoked. If an invoked operator calls a bpy.ops.bim.something in its invoke() function, then bpy.ops.bim.something will start and finish its own transaction, and then when the invoke finishes and finally runs execute(), another transaction will be started and finished. This means that we get at least one extra transaction logged (one per any call to bpy.ops.bim.foo in invoke()).
This mismatch of number of transactions and undo stack means that when the user presses ctrl-z, the undo doesn't actually occur. This leads to a sync bug.
To be safe, all IFC invokes must be wrapped. This will take some time to review so expect another commit soon.
Blender property tabs are hardcoded and we cannot customise them. IFC data only "somewhat" maps to Blender property tabs, and some things fail to map causing user confusion. For example material and styles are very confusing. Also scene and object properties are crazy overpopulated (see how many times IFCArchitect bulk collapses things). And this also causes things to be spread out and lost (e.g. some random panels in viewport N menu). This should give us a lot more control to organise panels exactly how we want them.
The layout uses three columns with a focus on a larger outliner (important as BIM models have lots of objects and complex hierarchies!) and properties, and removes the mostly irrelevant timeline for beginners.
if you switch ifc_class then relating_type_id can become invalid and we wasn't taking it into account
Also fixed bunch of warning like `pyrna_enum_to_py: current value '17' matches no enum in 'BIMModelProperties', '', 'relating_type_id'`` when some ifc_class has N related types and then you switch to other ifc_class that has less than N related types.
This reverts commit 4bc987924d since there was some unintentional changes.
Now when you use select_type in object properties - ifc class and related type gets selected in the BIM Tool - https://i.imgur.com/drIHYDz.png#3318
Massimo Fabbro
