From Richardson: "If you split relection/refraction at say, 0.6/0.4, what happens to the diffuse value setting? Is it still 0.4 ?" Reply from Ajax: " The sum of all three ought to add up to 1. Basically, you want all of the light coming off a surface to add up to 100% or less of the light that hits it, unless the surface is glowing or something." Errm - no, not quite. (I suspect that Ajax had "ambient" on his mind when he wrote that reply...) Refraction has very little to do with reflection, except in very special circumstances. Refraction is the amout by which light changes direction when entering/leaving a surface with transparency. Hold a pencil (or whatever) in a glass of water and look at it from an angle. The pencil seems to bend (abruptly) where it enters the water. It does this because the refraction index of water differs from the refraction index of air. Reflection is light being bounced off a surface. Since the light doesn't actually enter the surface (assuming total reflection), refraction doesn't enter the equation at all. There are times when it does, but that's usually only required for very close-up images... Cheers, Diolma