Hi Ramya,

If the script is actually able to run to the end but you just don’t see anything change, then I think pythonnet is correct, however please take David’s advice and ensure you’re not using pythonnet 3.0.

You might not have copied the entire script, but I don’t see where you initialize the type of connection from the zosapi module (zosapi.App() or zosapi.Interactive()).  So assume you have the proper connection to OpticStudio in another part of the script, I think you might be failing around lines 3-4; the LoadFile is looking for a full file path.  The default LENS.ZMX file which is loaded in OpticStudio has 0 aperture size, so I always like to add the following code immediately after a TheSystemLoadFile() command:

import zosapi

zos = zosapi.App()
TheSystem = zos.TheSystem
TheApplication = zos.TheApplication
ZOSAPI = zos.ZOSAPI

fullfilename = r'c:\user\Documents\Zemax\file.zmx'
TheSystem.LoadFile(fullfilename, False)

# this checks to make sure a valid file was loaded
if TheSystem.SystemData.Aperture.ApertureValue == 0:
    raise SystemError('The Aperture Value is "0".  Please ensure the filename is valid')

# rest of code goes below here

Also, unless it’s absolutely necessary, I would suggest simplifying how you generate your px/py values; there is no reason to use mgrid, vstack, revel, or transpose.  Since the pythonic way is to keep it simple, I would simply use 2 for loops (you can do this with a simple range but numpy already has the ability to normalize the coordinates with linspace):

n = 100
x = np.linspace(-1, 1, n)
y = np.linspace(-1, 1, n)
for px in x:
   for py in y:
      # make sure the ray is inside the pupil
      if px*px + py*py <= 1:
         # run code