On Oct 19, 2004, at 3:49 AM, Dennis Ranke wrote: > I tried to keep the code as simple as possible on the expense of > calculating the vertices more than once but didn't expect the result > to be this slow... I think it's all the trigonometric functions. >> For reasons I couldn't figure out, Dennis' solution returns a bunch >> of NaN points when dealing with the icosahedron primitive. > > The slerp method I used assumes that the incoming vertices are > normalized which the vertices of the icosahedron in your testdata > aren't. (It's evident that the length of Vector[ 1, GOLDEN_MEAN, 0 ] > is > 1) Ah, you're right, of course. Sorry about providing the messy data. (And thanks for catching it; it means I need to either normalize them or make a small change to my library.)