Use of PERTURB command in Tolerance Scripts for Thickness

Question

While populating the Tolerance Data Editor (TDE), the editor automatically generates and also allows the user to specify/modify the Adjuster with a specified column. But in tolerance scripting using PERTURB command, there seems to be no way to specify the Adjuster surface number while specifying the tolerance on a surface thickness . Is this a limitation of PERTURB command for scripting the thickness parameter or that Zemax automatically assigns an adjuster surface leaving no chance for the user to select another surface thickness?

Any help greatly appreciated. Thanks!

MichaelH · Answer

HiKrishna,The Tolerance Script (TSC) is a very low-level tool primarily designed to help automate multi-step tolerancing processes (typically for multi-step optical assemblies). To my knowledge, the TSC hasn’t been touched/updated in decades, even with the recent enhancements to tolerancing such as Roll operands, off-axis pivot tool, quick sensitivity & tolerance data retention.Almost all the effort for tolerancing has been put into the Tolerance Data Editor. I suspect the TTHI operand originally did not have anAdjustsurface so the PERTURB keyword originally did not accept theAdjustcolumn; when theAdjustcolumn was added to the TDE, the PERTURB keyword was not updated.There are several areas of the TSC that are more difficult to use than simply using operands + TDE (such as constraining the min/max values for a compensator) and I suspect this shortcoming fails into this category.Luckily, the Lens Data Editor has 2 solves which you can manually set to simulate theAdjustsurface:Compensator Solve (more useful)Position SolveThe Compensator solve is more useful because it only considers 2 surfaces while the Position solve could include multiple surfaces. For example, if I want to adjust Surface 2 and adjust Surface 3, the LDE & TDE might look like:Since both the Min & Max are the same value, I know that every MC file will have a S2 thickness of 1.1 and a S3 thickness of 1.4:If I want to get the same results from a TSC, then the nominal LDE should have a Compensator solve on S3 (note you need to include the thickness of both S2 + S3 in the solveSumvalue):This produces the same result when selecting User Script as the criterion in the Tolerancing window: