Hi @Nim - it looks like you sent a ZMX file instead of a ZAR. This means that your material catalogs and analysis windows were not included. Can you send the ZAR instead? Also, what analysis are you using to read the image size?

Finally - I am wondering what you mean when you say “A co-worker wrote a code in Matlab with the exact same system”. Is this code hand-written by your co-worker to calculate refraction? Or are you using the ZOS-API to analyze the same system? How is their analysis calculating image size?

Any information you can provide will help us to understand where the discrepancies lie. If needed, we can also move this into a private support case as long as your license is supported. Let me know if that’s a route you’d prefer!