Different results for the same code with different Ifc versions

Question

When I run the code below to get ifcWindow Area quantity using Ifc4 file and Xbim.Ifc4 interfaces it works perfectly.

But, When I'm trying to run on the same schema as Ifc2x3 file and using Xbim.Ifc2x3 interfaces it doesn't recognize RelatingPropertyDefinition property and performs the following error: error

Thanks

Answer 1

IFC 2x3 schema implementation in xbim Toolkit implements IFC4 interfaces to keep the code backwards compatible and to be able to write one code base for both schemas. But IFC4 doesn't implement IFC2x3 interfaces. RelatingPropertyDefinition is new in IFC4, so you would have to restructure the code. But bare i mind, that if you use IFC2x3 interfaces, it will only work for IFC2x3 files. If you use IFC4 interfaces, it will work for both schema versions. In fact, we plan that in the future there will always only be one set of interfaces to avoid confusion.