I've layered spheres before to get good-looking planets, as well as magical orbs and such where a glow or fuzz facter is needed. It is necessary to get the appearance of atmosphere. For dry worlds and airless moons, you need sharp shadows and crispness. It is all in the experimenting. :) More than a decade ago, someone named Joel (I'm blanking on his last name) wrote an article for Amiga which detailed how to build a planet and lay out the map in Deluxe Paint using the palette range and the gradiant brush tool to create the land masses and snow-capped poles. We wrapped that rectangular map around a sphere and... voila! It was oodles of fun and most of us game artists made lots of worlds. Carolly