Generation and Rendering of Fractal Terrains on Approximated Spherical Surfaces

Terrain modelling and rendering is an important aspect of modern computer games, computer generated scene rendering in movies and is also used in scientific simulations and geographic modelling. Rendering a planetary surface without polar geometry issues has long been a difficult problem, and this is exacerbated when simulation models need approximately smooth and equal areas. We have developed a terrain approximation algorithm suited for planetary surfaces, that achieves a reasonably uniform spherical approximation by combining polyhedral subdivision and midpoint displacement. We give details of the algorithm and some examples of its use.