Publisher Summary This chapter discusses a numerical algorithm for ray-tracing implicit procedural functions. It is simple, fast, and general to all continuous functions F : Rn→R. It features a screen space geometric error bounded by a user-specified value. The speedup scheme, which is important to good performance in rendering height fields, is general to all incremental height field ray-tracing schemes. It is possible to use other methods, such as Lipschitz conditions to speed rendering by extending the average stride length. This speed is conjectured to be linked to the algorithm's simplicity, which allows it to reside entirely in cache memory for near-optimum microprocessor performance. The chapter adapts the method to render measured height field data sets to add an adaptive level of detail. For this application, the fractal function F is constrained by the measured data to render such data sets with added stochastic detail.