portsmouth
commented
6 years ago Also needed to render volume caustics properly, e.g. https://www.behance.net/gallery/53917965/LENSES-TEST
Suggest to implement this initially just as an optional mode where we pathtrace backwards from a given laser beam direction, and connect each vertex to a randomly sampled point on the primary ray according to the volume transmittance. This should produce similar
(But cannot include the forward pathtrace simultaneously without properly accounting for MIS, which will probably be too complex).
Only really needed if we implement more general area lighting, in which case scenes with dielectrics generate caustics which don't resolve well in a uni-directional pathtracer.