Feature Request: Add Data 40 to NSRA to report the Face Number

Thanks Sandrine for submitting this.  Unfortunately, I doubt anyone else will request this (most customers probably don’t even know the capability of NSRA, let alone the few data points it doesn’t currently calculate).

Although it’s a small improvement, I think Zemax could highlight this for a future release.  You can essentially recreate the NSC Sag Map with native speed & without the need to save a ZRD file, which has caused a few issues in the past (there are other smaller benefits like implementing a Angle of Incidence as a Universal Plot/ZPL macro with a little more ease/user control or you could implementing a “Filter String” builder that could output Filter Strings which have a Face number component).  Basically, any programming logic that requires Face Number as an input or output could greatly benefit from this with probably less than 4 hours of Development effort.

It’s a little awkward that NSST (mixed-mode) has the Face Number for the segment but NSRA (pure non-sequential) does not.

Hey @Sandrine Auriol, the 2 main areas where this could affect me are:

• Non-Sequential CAD to Sequential Extended Polynomial conversion (think CAD windshield for a HUD system)
• “Sequential” Stray Light analysis

I need to save a ZRD to disk for each of these processes and having direct access to Face Number programmatically without saving & parsing a ZRD can help with speed and stability.

For the CAD to Extended Polynomial, I use the same concept as the NSC Sag Map where I trace a grid of rays in the Z direction and simply get the z-sag component of the ray intersection.  The CAD part will need to be converted into 2 surfaces in Sequential mode so I need to know which face the ray hits.  Once I have the grid of sag data, I can exploit symmetry if needed & fit an n-th order polynomial (up to 10th order for Extended Polynomial) to the dataset.  Finally, I can save the sequential LDE with the 2 surfaces and then use the Insert Lens feature to add this to my optical system.

For the “Sequential” Stray Light analysis, I shared my vision for this with Bob & Tom last year at Optics & Photonics.  The concept is to create a copy of the optical system, convert this copy to non-sequential mode, run a non-sequential ray trace & then analyze the paths.  The few filter strings I use the most in this analysis are:

• X_XGT/X_XLT/X_YGT/X_YLT to isolate a region of interest on the detector
• X_IRLT to eliminate the intended path in the ROI
• Gn for ghosting off a lens
• X_HITFACE2 for double bounce ghosts

I always group these last two filter strings together (see my answer for Filter String for Ghost Analysis | Zemax Community) and when using a probing a ray to determine the Face Number for X_HITFACE2, saving a ZRD becomes very time consuming for a single ray.

I would need to perform the CAD to Extended Polynomial analysis maybe every 2-3 months but when I do the analysis, I need to analyze dozens of different CAD designs.  I perform the Stray Light analysis on a weekly basis for different designs, especially during the prototype phase if there is stray light once the entire camera system is assembled. 

Hi @MichaelH and @Mark.Nicholson ! Thank you for your comments. Yes I agree that it can be frustrating. I’ll take care of the feature request. Thank you.