Generating extraterrestrial terrain

In recent years, generating both realistic and fanciful terrain has roused substantial interest among computer graphics specialists, motion picture and special-effects artists, geologists, and even mathematicians. Most fractal terrain models have been based on Fourier filtering, midpoint displacement, Poisson faulting, and successive random additions. Techniques such as these, while often creating convincing fractal forgeries of natural mountain terrain, do not always account for the fact that mountains are not statistically self-similar or identical from top to bottom. Nor do many prior methods naturally account for the beautiful ridges, craters, streaks, and various other features often associated with extraterrestrial terrain. The simple, flexible approach I present creates aesthetic extraterrestrial terrain with rich structures of varying asymmetry. >