After some testing, I can confirm the problem. The coordinate system at reference points works for loads - concentrated force, - but it does not work for boundary conditions.
I see three possible solutions:
- Disable this option for BCs
- Show a warning when such an option is used
- Internally recompute the BCs to the selected coordinate system. This would work, but could give the user a feeling that the RP’s node is in local coordinates when analyzing the results (this is probably negligible).