slin's shadows (which are great for learning even if they aren't perfect - thanks for sharing!) use a similar idea but i think with pssm the splitting scheme is more sophisticated which will lead to better results:
http://www.coniserver.net/ubbthreads/showflat.php/Cat/0/Number/819786/an/0/page/0#Post819786but there is no example for gamestudio yet. i didn't get my try to work yet.
