I'm a bit puzzled how best to handle two touching, but different materials. Lets assume material 1 extends for 0,0,0 to 0,0,1, and material 2 should go from 0,0,1 to 0,0,2. Do you end 1 at 0,0,1, and start 2 at 0,0,2, or perhaps have a very small gap between them, even though they are supposed to be touching. For example, should 1 end at 0,0,0.99999999 and 2 start at 0,0,`1.0000000001 ? I wonder what happens with rounding errors in the floating point processor some times.
Deborah