Is there a way to disable the specular/transmission visibility of an analytic light aside from turning off the spec/trans contribution or light-linking?
For example, I would like to have a quad light not be visible in a mirror but still have specular contribution. I understand that the specular reflection of a light is part of it's specular contribution but I was hoping there's a workaround, similar to how trace sets work with geometry.
1. Turning off specular contribution, but it turns specular rays completely off, not just the visibility of the light in the reflection.
2. Using light-linking, which again effectively disconnects the light from the mirror
3. Trace sets: do not seem to work with lights, only geometry.
4. One workaround is using mesh lights and creating a trace set with the geometry and add it to the trace set for the mirror.
(On a similar topic, mesh light does not have transmission contribution attribute, is this intentional?)
I want to avoid rendering multiple passes and/or compositing as well as using LPE's.
Any details on how best to go about setting this up would be great.