Andrew Price over at Blender Guru recently released a new tutorial on how to make a realistic looking asteroid using some really simple modifiers and simple tools. Some of the specific things he shows you are how to use displacement maps to generate rough terrain, how to apply a tiling texture, how to create a randomly generated particle field for debris and how to use the compositor to fine tune the appearance of the finished image.
Here is my finished result from my first try.
PS. Make sure to check it out at the 1080P resolution.
UPDATE:
I decided to try it again with more detail and some changes to the overall feel. The only thing I don’t like about it is the smaller rocks that fly into the main asteroid instead of bouncing off.