Answer:
The "Simulate and Generate Wind Loads" interface application allows you to exchange member, surface, and solid elements in RFEM, and member elements in RSTAB.
To avoid mesh that is too fine and thus calculation time that is too long, the program simulates all members with a rectangular cross-section by default. In this case, the size of the rectangular cross-section is selected in such a way that it barely includes the real cross-section geometry.
By deactivating the "Export optimized member topology" option, you can avoid this additional optimization of the model and allow consideration of the real cross-section geometry within the existing cross-section settings.
If the exact display of the cross-section geometry requires more than 1,000,000 elements, the interface automatically switches to the simplified rectangular cross-section display.