Hello Alicia,

Thanks for your question here on the Community forums!

Unfortunately, currently, the data input for the Grid Sag surface type is limited to an evenly spaced rectangular array of sag points.

The proper file format is always as follows:

nx ny delx dely unitflag xdec ydec z dz/dx dz/dy d2z/dxdy nodata

For more details about the formatting, please take a look at the Help files at:
The Setup Tab > Editors Group (Setup Tab) > Lens Data Editor > Sequential Surfaces (lens data editor) > Grid Sag

That said, you may apply a circular aperture in OpticStudio, or zero out all the data points outside of the region of interest directly in the .DAT file, if it is necessary for your application.

You may find more details about how to create the required .DAT files programmatically in this knowledgebase article:
How to write a Grid Sag DAT file programmatically – Knowledgebase (zemax.com)

If you have any further questions, please do not hesitate to ask!

Best,
Csilla

That’s true of the Grid Sag surface, but if you have a rotationally symmetric surface you can also use the Cubic Spline and Extended Cubic Spline surfaces.  

Thank you very much for your answers, I will try to use a surface different from the gird sag then

Kind regards,

Alicia