Hi, > I think I understand it. But if I understand it right then I don't > understand why you don't put the randomization before the turbity object.
It is just a matter of the order of the computations. When you randomize the position, you need to compute the new map coords value from the new position. It was earlier done by the material map object (parallel, sphere or whatever map - the material should actually be independent of that). When the position changes, how can you re-evaluate Map coords again ? How does the VSL code know what kind of parent mapping was applied (what type, what size etc?). The answer is: using the Map vsl object, which re-evaluates the parent mapping. > Ray tracer: render engine computes position > Material mapping: Parallel map computes Map coords from position > Material: > randomize map coords **** how ????? > Position changes by randomization > Turbidity is computed from randomized Map coords I highlighted the important row above. How can you randomize the map coords channel so that it's randomization matches the randomization oif the position. Maybe you Map coords randomization goes to negative x axis direction, but position goes to +x axis direction! I repeat: Map coords depends on the size, orientation and type of the parent mapping, and VSL code normally does not know these. Map object takes care of such details:) Best regards, Vesa
