I'm working on a project and we want to create a render that is stylized in a painterly art style that is all the rage these days. One of the areas I'm struggling with is how to color these strokes. The overall concept seems rather straightforward. Create point cloud with instanced cards, sample the color of the path traced camera ray, apply that color to the card. I'm a little stuck as to how to sample color data from the path tracer. I see there's a karma point read node, but that samples data on the geometry, not data generated by the ray caster at render time. I also looked at the karma ray import, but that also doesn't sample the combined color of the ray bounce. What I've found that pretty spot on for what I want to do is this. [zenopelgrims.com] Which is an arnold setup that uses a plugin to extend the aronld renderer. Is Karma capable of achieving this type of effect with its current mtlX nodes or would a more custom extension need to be written in order to make this work.
Cheers.