SpeedRock: procedural rocks through grammars and evolution

Abstract

We present an approach to procedurally generating diverse and believable rocks for usage in games and virtual worlds. The basic idea is to evolve rulesets for three-dimensional L-systems. The fitness calculation involves expanding these rulesets a number of times, collapsing the resulting structure and evaluating how well the collapsed structure conforms to a user-specified shape. Texture is then applied through ray-casting from a sphere around the evolved "skeleton". The result is a lightweight, stand-alone tool for rock generation capable of exporting assets to mainstream modelling programs.