Syntax: fracland [surface] "seed" "subdiv" This primitive creates a fractal surface centered at x = 0.5, y = 0.5 and ranging from x = y = 0 to x = y = 1. It is actually a heightfield primitive that is generated within rayshade rather than being read in from a file. The "seed" value is the seed for the random number function. The seed value specifies the shape of the surface -- changing the seed value will randomly change the surface shape. The "subdiv" value is the number of subdivisions for the surface -- subdiv = 0 will produce a flat square, subdiv > 0 will produce a square with an ever more detailed surface. So far, rayshade seems to have trouble with subdivisions greater than eight (if anyone finds otherwise please tell me!!) and produces surfaces with "holes" in it for values greater than this. The number of points in the surface follows the following formulas: size (number of points per side) = (2^subdiv) + 1; total points = size^2. The four corner points will always have an altitude of zero, the max altitude should never be never be more 1.0 and the min should never be less than -1.0. Any bugs or comments can be sent to me at lcoffin@clciris.chem.umr.edu. ---Larry Coffin lcoffin@clciris.chem.umr.edu