Export a roof as IfcSlab

[G_GRIESSEN]

Hello

I'm trying to export a roof as IfcSlab, but it is not working, it stays a roof no matter what I try.

First I opened the Ifc Export options and changed Roof to IfcSlab. That didn't work.

Then I tried the parameter IfcExportAs. Also no luck.

Is there any way to achieve this?

Thanks in advance.