The NSC Surface Sag (available in Ansys Zemax OpticStudio 2023 R1 and OpticStudio 23.1) is fully implemented in ZOS-API. It means that you can open that analysis, define the settings and get the results. It makes it easy to convert an object face into a Grid Sag Surface.

Here is an example of a Matlab code:

TheSystem=TheApplication.PrimarySystem;

MyNSCSag = TheSystem.Analyses.New_Analysis(ZOSAPI.Analysis.AnalysisIDM.NSCSurfaceSag)

MyNSCSag.HasAnalysisSpecificSettings

returns True

The settings are:

MyNSCSag.ApplyAndWaitForCompletion

MyNSCSag_results = MyNSCSag.GetResults

returns a DataGrid containing the sag points

Sag = MyNSCSag_results.GetDataGrid(0).Values.double;