Aye, aside from what Ornlu and the others said, Diolma, you ALWAYS encounter TIR in real life. At a level that is inifinite... Bryce, or ANY renderer, cannot handle this quite yet. Which is why in Bryce 5, you can set the depth of this effect, the higher the depth, the longer the render... At 100 Ray Depth/TIR, this image would probably take a much, much longer time than at 8, for example...