So perhaps the question is how to get a Surface Model from an IFC model using ETABS ?
Probably not easy. But I don't know of any programs that can generate file formats that ETABS can use for structural surface analysis either. Probably have to just use the IFC model as an aid in modeling it all over again with ETABS ?
Did you try classifying the ArchiCAD IFC model as "IfcStructuralSurfaceMember" before saving it as an IFC file?
Theoretically that should be a part of the IFC file that ETABS can import and use for analysis.
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