Can someone help me out? Sidefx used to have their legacy tutorials online but no more. There was a good one for creating fake caustics using a vex compositing filter which I believe used voronoi noise but I can't remember how it was done. Does anyone remember or know where those legacy tutorials exists?

Don't remember this tutorial but I'd do this like presented in hip file. This is quick attempt. This can be extended of course. Caustics map is generated in COPS then projected onto geometry via light. Rays are created with zmap fog. I reduced sampling quality to speed up rendering.


(Turn on atmosphere “god_rays” to render with rays).

Thanks. That's exactly what I was looking for.

you are welcome!
cheers,
sy.