Here's my first feeble attempt at Mark's approach... Still has a ways to go obviously; my handle on Carrara's shaders isn't as deep as it should be. Uh, let's see: Simple (hidden) cloud mesh with a squashed sphere distributed over it via a surface replicator. For the sphere shader: Simple gray color, Noise Factory alpha, turbulence displacement One high-intensity bulb in the middle. I guess this is a good place to start; suggestions? This is FUN!