Hello,
In Cinema 4D there is a Xpresso node called "pmatterwaves" that lets one spawn particles based on light rays that hit the surface of an object. What would be the most straightforward way to achieve a similar effect in Houdini? I understand baking out light maps is an option, and also coding some custom ray trace calculations in VOPs or Wranglers, but if one didn't want to do neither, would there be some straightforward ways to get this information into SOPs, based on light values and positioning in the scene, a setup with just a few SOP VOP nodes. I've had a few ideas, but many of the lighting model related shader VOP nodes seem to be absent in SOP-context VOPs. I'd assume there have been enough people to want light-surface interaction effects, that there would be some relatively simple way.
This is more of a theoretical question. I'm not stuck on any current project, and my aversion to using light maps is mostly because of wanting to find possible alternatives.