In some cases the EC3 checks in RFEM's add-on module RF-STEEL EC3 give an error message "non designable". This can be due to a moment or torsion on a non symmetric profile:
As you can see in the screenshot above their is a design issue with a cold formed profile because of torsion.
You can change the max. portion limit in the details of RF-STEEL EC3:
If you change it you should be sure that the torsion as okay according to this limit.
Better solution is to use our new module RF-STEEL Warping:
This new add-on has a 7th degree of freedom and can check also these previous non designable cases.
Hereby a link to a webinar related to this specific topic:
https://youtu.be/Ym4GRiyx3UE?t=15m44s
You can download the latest RFEM release here and test this feature: