Hi Aaron,

Your current model is running in hybrid model (sequential with an NSC object included).  In this case, the sequential rays coming in through the entry port cannot split:

However, if I make your STL plate reflective, then the sequential rays make it out of the NSC group:

I think the best way to model your system may be full NSC mode.  If needed, you can optimize a lens train in sequential mode, and then convert it to NSC using the built-in conversion tool.  At that point you can add one or more sources, along with other objects as needed, and then utilize all of the ray tracing features provided in NSC mode.

That being said, if you are only interested in rays that reflect from the plate (and don’t really need ray splitting per se), then you can just use a fully sequential model in which a tilted plate surface has a material setting of “mirror” (so propagation space becomes negative after reflection), and whatever coating you like can be included on this reflective surface.