SamTherapy, good question. I don't have the technical know-how of L_D but perhaps you could use the color picker to sample the hue of the object that you want other objects to "gather," then apply that color to subtle shadowless soft spotlights aimed appropriately? What I want is a relfection catcher in addition to the shadow catcher. Imagine the possibilities if an object could be made invisible with the exception of relfective properties. By the way, I've seen biolumenescent jellies with pink spots at the Monterey Bay Aquarium. Nelif, your jellyfish node is beautiful. Cool work!