Hi Bernd,
Thanks for the update. In fact this issue ended up to create a few others for me that I reported into the Mac Version of FreeCAD and OCCT v6.x which crashed pretty "easily". I requested for a move forward with OCCT 7.0.0 which is fixing the issue I meet on Mac with OCCT optimized but requires a lot of changes into FreeCAD code, as well as FEM wb due to OCCT dependency. The other things is that the SMESH and meshing interface used from Salome is crazy old so I have updated to latest version of Salome 7.7.1. I have been able to recompile everything but still face some challenges on the Hypthesis interface which has totally changed from 2008 (hey the FreeCAD code on this side is crazy old). I will stop for now my tests except if I find somebody with the wish to move forward with me on this long path.
I will move back to a more "traditionnal" version and check if I can run the math of my stair on the Mac machine.
vejmarie