There are other things it's been used for like optimising roughening/regularisation parameters for light transport in order to provide better caustics with forw

There are other things it's been used for like optimising roughening/regularisation parameters for light transport in order to provide better caustics with forwards path tracing: https://diglib.eg.org/handle/10.1111/cgf14347 https://diglib.eg.org/handle/10.1111/cgf14347