Hi everyone!If you have ever tried to find a good reference for modeling a beam splitter in Zemax, you have probably noticed that most examples either go the Non-Sequential mode, which means losing access to aberration metrics, OPD, MTF and all the sequential analysis tools we rely on, or they use Sequential mode but with a multi-configuration setup, which works but can get unnecessarily complicated depending on what you are trying to simulate.After going through that myself, I put together this guide in case it helps anyone who runs into the same situation, since getting this right can be trickier than it looks. The goal is to show a simpler path: a non-polarizing beam splitter modeled entirely in Sequential mode, in a single configuration. No mode switching, no extra configurations. Just a clean sequential system that still gives you full access to all the analysis tools.To keep things concrete, the system I will use as an example is based on this layout, which is pretty close to wha

Hi guys!I am working on a tolerancing analysis of an optical system that includes a beam splitter, and I have come across a coupling issue that I would like to understand better.In the nominal configuration, all elements are centered and the system is fully aligned.When I introduce a Y decenter of +20 mm on the beam splitter on the lens data editor, this physically displaces the element along the vertical arm of the system. As a result, the optical path length in that arm should change accordingly. A +20 mm decenter on Y should reduce the effective thickness by 20 mm, from 239.617 mm to 219.617 mm. However, Zemax keeps the thickness at 239.617 mm regardless of the decenter, which is not physically correct.My question is: is there a way to link the Y decenter of the beam splitter to the thickness of the preceding surface, so that when the beam splitter is decentered by a given amount the thickness is automatically compensated by the same value? Ideally I would like to keep using TPAR to

Hi All,I am currently designing a low‑cost imaging lens for a sports application. In my lens model I use the REAY operand to control image height, the RAID operand to control chief‑ray angle (CRA), DIMX to control f‑theta distortion, LACL for lateral‑color correction, RSCH for spot size and MTFT/MTFS for resolution across the field. During optimization I can obtain either good MTF or good lateral color with CRA and distortion depending on the operand weightings, but I cannot find a stable balance even when I adjust the weights gradually. In both cases, my geometric spot‑size results were poor. Please suggest optimization techniques to achieve a better trade‑off, or alternative approaches to indirectly control these parameters.Note: candidate glass materials must have hardness greater than 450. Thank you in advance for your support.

HiI am trying to analyze scatter contribution in my imaging system for off axis mirrors using different surface roughness. For example I have calculated the A, B & g values for 10nm surface roughness and used those values to create an ABg file in the ABg scatter catalog,the TIS calculator showed 0.0058030 (The value is less than 1%).While trying to assign this created ABg file to the mirror the following error on Total integrated scatter pops up.Can anyone help me in understanding this error pops up  when my calculated TIS is less than 1% ? 

Dear all, In the manual, it is written : “Samp: The grid size. A value of 10 would yield a 10 x 10 grid of rays”. I need to use CENX(Y) with the highest accuracy. What is the maximum acceptable value of samp ? Is there another way to increase the accuracy of CENX(Y) ? Many thanks. Best regards, Thierry. 

Dear all,I’m working on a project of ultra-precise micro-arcsecond relative astrometry space observatory (Theia). Especially, I need to map the image plane (0.5°x0.5°) with a very high accuracy. For instance, I have to study the variations of positions of the PSF (with CENX/CENY) due to some perturbations (distortion, tilts of the mirrors...).By default, the number of fields is limited to 2025 for my premium version, but I would need 100x100 fields.It’s rather easy to generate such a new grid, but the parameter “i” (field number) of CENX/Y refers to the (default) field table.Is there a way to use CENX/Y with this new grid ?Many thanks,Thierry.

Dear all, I updated this morning to Zemax 2026 R1.01. Since then I get the following error message when trying to connect to Zemax with Python via API (e.g. by using the PythonStandAlone_01.py file):“InitializationException: Unable to locate Zemax OpticStudio.  Try using a hard-coded path.” Did anything change here? Thank you and best regards, Gregor

Hi all, unfortunately, I have a serious problem using Zemax. Since two days, Zemax (2026 R01.1) freezes completely after opening. I am currently in close contact with my IT department, however the problem has not been found so far.  It seems that other users are still able to open Zemax on my machine and I am still able to use Zemax on other laptops. I didn’t update to a new version, it just didn’t work anymore from one day to the other. Maybe there has been some update from my windows involved (Windows 11 Pro). Has anybody else similar problems? I used the “repair function” for Zemax, but it didn’t help. Moreover, I installed the former version again (2026 R01), yet it freezes as well.   All the best, Gregor  

Hello,I would like to model the propagation of a polarized light beam through a biaxial crystal.While methods for uniaxial crystals seem to be well established, I am unsure how to approach this problem for biaxial crystals.How do I handle this case?Thank you very much for your help.Best regards,Dirk

From this KB it is clear that we can pivot an element about any arbitrary pivot point in space. This is Ok for intermediary optical elements in the optical chain but breaks when you want to pivot either the Object of Image surface.Here is a an example showing a simple Optic Fiber with Chief ray centered on to Image surface. How can I pivot Surfaces 1→3 about the Pivot point centered on the Image surface?