Attached Link: http://www.renderosity.com/mod/forumpro/showthread.php?message_id=3523037&ebot_calc_page#message_3523037

it works in carrara with refractive squares of zero thickness (see att lnk).  ask in carrara forum for details.  they don't always answer the hard questions, but this is an easy one.

in re: poser 7, the short answer is no.  poser 8 or later, yes, but it's either gonna be a lousy-looking
diffuse effect using IDL and translucent channel and some fake lighting tricks, or a crazy-looking
effect involving a coloured image map applied to diffuse and/or specular channels of directional lite.
it's not strictly a caustic effect, as it works in carrara with caustics disabled.