@Teun another relevant discussion: Proposal for standardisation of property set relationships
In IFC4, it became a lot more “standardised” to support material properties. In fact, I have a line of source code in the BlenderBIM Add-on which says this:
return False # We don't support material psets in IFC2X3 because they suck
If materials become rooted, then it becomes even easier to support them. If you’re looking for a free and open source BIM authoring tool that support IFC4 material properties, the BlenderBIM Add-on might help. For IFC2X3, it seemed too painful for what it was worth (IFC2X3 materials in general were missing a lot of basic information). I’m curious to know if anybody has implemented it for IFC2X3.