At the moment the non-permanent GUIDs are “faked” to look like the permanent GUIDs, but there should not be any real need to do. This is only causing problems to regression testing , to diffs, etc.
Therefore I’m proposing to have an null-GUID for non-permanent GUIDs i.e. ‘0000000000000000000000’
The only thing what we need to agree is that this particular GUID value has a special nature and does not need to be unigue in the IFC model. Many entities could share the same GUID.
This would also improve the certification process and testing , because now the non-permanent GUIDS are more visible.
This agreement has no effect to permanent GUIDs of physical entities.
Of course it would be the best not to need non-permanent GUIDs, but unfortunately that is not the case at the moment. For example property sets and quantity sets have GUIDs that needs to be created on-the-fly, because there is nothing corresponding in the native data model.