in regard to antoine clappier's gemstone render (see attached). my question is: how to light the scene to get the same brilliance - the little spots and lines of caustics. I know where to get cut stones, what general settings to use in refraction and transparency. all those are covered in previous threads here. however, I wasn't able to find a thread that describes the lighting. there are at least two refs to antoine's gem tutorial, but I believe that's about how to model the gem. when I try the render, I get pools of caustics under the gems, but not the lines and spots as in the attached. p.s. I tried it in poser first, as somebody said it could handle caustics thru some means, but I found it was hopelessly slow in any case.