For the .STL (only FW) the mesh looks pretty good, doesn’t it? And the same I would say for the .STEP… (By the way, do you know why in the .STL case 9 M volumes are created -only 2 M for the .STEP-?).
However the same errors appear again and again… But the simulation for the .STEP worked fine!! Do you know why did it work? It would be a valuable information.
And how did you split the .STEP FW in several parts? I am not able to do it.