Answer:
CAD programs that are not primarily used for structural design usually model the structural elements as solids. A simple rectangular column would consist of 12 lines and 6 surfaces, for example (see the image).
The solids can also be defined in different ways. Either by the boundary surfaces (BREP) or as a sort of "swept solid". The difficulty now is to generate a 1D element from this 3D element. This is usually only possible if the solids were created as a swept solid. The "face" surface defines the cross-section. The correct member position can be determined by the direction and length of the extrusion.
However, in your case, it is a BREP. At this time, we cannot guarantee the correct conversion for this type. This is also referred to in the warning that should appear during the import.
