Unexpected ROT-DEF error

Dear community

My name is David and I try to rotate a custom FLUKA model for arbitrary yaw, pitch and roll angles.

I’ve implemeted this rotation in my FLUKA model using the ROT-DEF cards in combination with the transform card. Now, for a very specific angle, I get some unexpected geometry errors highlighted in FLAIR. These angle is Yaw=45 degree (TH_yaw parameter in the attached input script). For all other tested angles, no errors occured.


  1. I have no idea, what the reason for this error could be. Is there a problem with my geometry?
  2. How can I prevent such errors?

I’ve copied the problematic region to the input file “rotation_test.inp”. The three rotation parameters are TH_yaw, TH_pitch and TH_roll. As already said, the problematic angle combination is TH_yaw=45, TH_pitch=0 and TH_roll=0.

rotation_test.flair (4.3 KB)
rotation_test.inp (5.3 KB)

If you need more information/details or have further questions, please contact me in the personal fluka section or by e-mail (david.breitenmoser@psi.ch).

Thank you very much for your support
Kind regards,

P. S. I’ve used the newest CERN version FLUKA4-3.1 for the test simulations together with the newest FLAIR software version 3.2-1.

Thank you @BV96 for the bug report. This error is already fixed in the development version of flair. In the next days we are going to push an update of flair correcting it.

Hi Vasilis

Great, thanks for your swift reply. So did I understand correctly that this is a FLAIR bug an my geometry input is correct?

I’m looking forward to the new FLAIR version!

Thanks for your support.