Hi Kevin, 

Are you referring to the True FreeForm surface in the lens data editor? I'm assuming that you are looking to optimize different propreties of this freeform surface to meet your illumination target of interest.

What kind of target illumination pattern are you looking to optimize too? And what kind of source are you using in your setup? Generally, non-sequential mode is more suited to tasks involving illumination analysis (including optimizing to an illumination target via bitmap optimization).  If you let me know what illumination pattern you are looking to optimize to, I'll be able to better answer your question! 

In the MyZemax knowledgebase, I was able to find an article that details how to transform a Gaussian illumination pattern to a top hat profile in sequential mode.  I've linked this article below.  However, this is a limited application and only involves using one field point in the system.  I thought you would at least be interested in taking a look at this article to help get you started in terms of thinking about what is possible in sequential mode.

How to design a Gaussian to Top Hat beam shaper · MyZemax

Looking forward to hearing back from you soon! 

Best, 

Jordan Teich

Hi Kevin,

Thanks for your post here on the forums. I just wanted to touch base here as I noticed that you had a case not too long ago on this topic as well. Did you have any outstanding questions on this topic?

In short, as Jordan said, I think the best route to using the TrueFreeForm surface to get the distribution you want will come down to the Merit Function Editor definition. For TrueFreeForm, the strength of that surface is that you have different surface definitions to expose as variables -- Zernike Standard Sag, Even Asphere, and discrete point-by-point control, to name a few. So, while you can set different parameters as variables, what it will come down to is constructing a merit function that targets your desired distribution. Since Bitmap Optimization is not supported in Sequential Mode, you will need to construct a function using operands like REAY/REAX to target landing coordinates of specific rays in your pupil at certain locations. This is what the article that Jordan shared demonstrates. If you have an idea about the shape you're looking for, a good place to start might be thinking about how rays that fill the pupil need to land on the image plane to generate your desired shape. This is really the most direct way to get a 'pattern' target in Sequential Mode. Depending on the pattern you want to achieve, your merit function may need to become quite granular in the targets:

Thanks again for your post!

~ Angel