Yep, I use TIR (usually set on 12 or more) every time i render glass objects, which turned to disaster when I rendered my Chess image (129 glass objects), I turned on everything : soft shadows, tir on 24, and ray depth on 20, it rendered for more then 15 days, so be careful with Bryce 5, lol, new options are cool but sometimes time demanding (usualy TIR itself is not that bad) !!! :)