Hi Daniel,

Here’s how I would access the field number of a Huygens PSF analysis in a Python interactive extension:

# Open the Huygens PSF analysis
huygens_psf = TheSystem.Analyses.New_HuygensPsf()

# Get analysis settings
huygens_psf_settings = huygens_psf.GetSettings()

# Get field number
field_number = huygens_psf_settings.Field.GetFieldNumber()

# Print field number
print('Field number: ' + str(field_number))

# Close the analysis
huygens_psf.Close()

The result in a new filed looks like so:

Field number: 1

Hope this helps.

Take care,

David

A further update:

I downgraded to python 3.8.13, and the issue persists exactly as before. It seems like it’s an issue of New_HuygensPsf() returning an instance of the base class IAS_ rather than IAS_HuygensPsf(). This is actually consistent with the documentation, but it’s strange that the consequent behavior differs from David’s expectation. Casting with typing.cast as in my original post solves this issue for the settings object but does NOT solve this issue for the object returned by huygens_psf_settings.Field. I provide a modification of David’s code to demonstrate:

First, casting huygens_psf_settings:

# Open the Huygens PSF analysis
huygens_psf = TheSystem.Analyses.New_HuygensPsf()

# Get analysis settings
huygens_psf_settings = huygens_psf.GetSettings()

# MY ADDITION: Cast huygens_psf_settings
import typing
huygens_psf_settings = typing.cast(huygens_psf_settings, ZOSAPI.Analysis.Settings.Psf.IAS_HuygensPsf)

# Get field number
field_number = huygens_psf_settings.Field.GetFieldNumber()

# Print field number
print('Field number: ' + str(field_number))

# Close the analysis
huygens_psf.Close()

This resolves the issue raised by David’s original code as per my previous reply, but produces a new error:

Found OpticStudio at:   %sc:\program files\zemax opticstudio                                                                                                                                           Connected to OpticStudio                                                                                                                                                                               Serial #:  L118546                                                                                                                                                                                     Traceback (most recent call last):                                                                                                                                                                       File "PythonZOSConnection1.py", line 126, in <module>                                                                                                                                                    field_number = huygens_psf_settings.Field.GetFieldNumber()                                                                                                                                         AttributeError: 'PropertyObject' object has no attribute 'GetFieldNumber'    

Here, we circle back to the original problem presented in my first post. huygens_psf_settings.Field does not return a type consistent with the documentation! I think this is a bug, and perhaps I should open an issue. Anyway, proceeding further to cast this result of huygens_psf_settings.Field to the type that should be returned according to the documentation leaves GetFieldNumber as an unbound method, and calling it raises an error of “incorrect number of arguments” because it has no implementation. This seems to me to be a problem with ZOS-API itself, but I may be wrong.

I am using Zemax OpticStudio 22.2.1 Professional (64 bit)

Hi David,

Thank you very much for the response, you were right. I downgraded pythonnet to 2.5.2 and that resolved all issues. I was previously running pythonnet 3.0.0 which explains everything.

Thanks again for your time,

Daniel