I don’t see how to correctly use the values of the “PredifinedType” attribute in IFC.
I had understood that when it’s set to USERDEFINED, it’s for example the “ObjectType” attribute that should be used to define the granularity of the object.
However, whether “PredifinedType” is set to USERDEFINED or NOTDEFINED, it doesn’t change the value of “ObjectType”.
Could someone please enlighten me on the use of these two values?
Thanks in advance

Your understanding is correct that if you set PredefinedType to USERDEFINED, you need to fill out the value in ObjectType (for occurrences, or ElementType for types).

This is up to you to fill out manually in your IFC authoring software. IFC will not know what your userdefined type is.


All right. Now I understand.
Thanks for the clarification.

Thanks for the clarification @Moult I had a strong struggle today with the concept.
Just out of curiosity, after my experience with Vectorworks and Revit, I am afraid is either difficult or not-possible to define “ObjectTypes” as they are not actually related to any “object” in the authoring softwares. Am I wrong?

You can fill out the object type in Revit. You can use this type parameter or this instance parameter.

I haven’t used Vectorworks.