Caustics refers to the light bending lens quality of glass and liquids. Carrara does not support that at this time. The work around for that is to create some gels and apply them to lights in appropriate places as in the example above. If I had any spare time today I'd tweak the gel that's inside the glass for a better rim refraction but I've gotta pay the bills. :*0 Other uses would be underwater scenes, and any scene where there is glass type of objects. Some of the pixel pushers with programs that have caustics still create gel/light set-ups to avoid speed hits in rendering plus complete control over the caustics themselves. (there are times that you may not want them everywhere) Pretty fun stuff. Mark