Question about coordinate rotation using transformPoints -rotate

[CGH20171006]

Hi everyone,

I find that the following command is in some LaserBeamFoam tutorials:

runApplication transformPoints -rotate '((0 1 0) (0 0 1))'

It seems that this command rotates the coordinate system, but I’m not quite sure about its purpose.
Could you please clarify:

• Why this rotation is needed — why not just define the correct orientation at the beginning?

• Which coordinate system is being rotated here — the mesh, the laser, or another reference frame?

Any explanation or reference would be greatly appreciated.

Best regards,
Guanhong Chen