Hello Zemax Community,

I've modeled a freeform lens in sequential mode using the Extended Toroidal Grating Surface Type in Zemax. I defined my lens with parameters for Radius, Conic Constant, and Extended Polynomial Terms. Since the lens is an astigmatic component, it has curvature along the Y-axis while remaining flat along the X-axis, which is why I selected the extended toroidal grating surface.

When I converted the sequential model to a non-sequential model using Zemax’s “Convert to NSC Group” feature, the lens appeared as a combination of Standard Surface, Grid Sag Surface, and Compound Lens. However, the performance doesn’t match my original sequential model, and I suspect the conversion process may not have fully captured the lens design.

My question is:

• Is there an object type in NSC mode that allows me to manually enter my Radius, Conic Constant, and Extended Polynomial Terms to recreate the lens accurately?
• Are there recommended steps for converting this type of lens from Sequential to Non-Sequential?

Thank you in advance for your help!

Best regards,
Ben