You can fake radiosity though.. create a low-intensity radial light, adjust the falloff (ranged falloff) to where you want it, and put it inside the mountain. Then select the mountain, go to material editor, and in the same dropdown list as the Light choice uncheck "cast shadows". That'll let the light shine through. You'll have to play with it to get the effect exactly how you want it, but it's pretty useful. Unfortunately, there's no way to set selective lights just yet.. maybe in Bryce 5? =) Rosh