Hi, 

I would like to step in here because I am trying to see diffraction from a prism plate, which in my design is imported as a CAD file. 

Firstly I have displayed coherent irradiance on a rectangular detector, but from my understanding I have thought I should make the CAD a user defined aperture as well. 

If this is right, how do I convert a CAD into a UDA to simulate diffraction?

Thank you very much for your help,

best,

Giulia.

[MOD split off into separate post thread.]