Heightfields have proved to be useful for rendering terrains or polygonal surfaces with fine-structured details. While GPU-based ray casting has become popular for the latter setting, terrains are commonly rendered by using mesh-based techniques, because the heightfields can be very large and hence ray casting on these data is usually less efficient. Compared to mesh-based techniques, ray casting is attractive, for it does not require to deal with mesh related problems such as tessellation of the heightfield, frustum culling or mesh optimizations. In this paper we present an approach to render heightfields of almost arbitrary size at real-time frame rates by means of GPU-based ray casting and clipmaps. Our technique uses level-of-detail dependent early ray termination to accelerate ray casting and avoids aliasing caused by texture sampling or spatial sampling. Furthermore, we use two different methods to improve the visual quality of the reconstructed surfaces obtained from point sampled data. We evaluate our implementation for four different data sets and two different hardware configurations.

@article{FH12,
  author = {Feldmann, Dirk and Hinrichs, Klaus H.},
  title = {GPU based Single-Pass Ray Casting of Large Heightfields Using Clipmaps},
  journal = {Proceedings of Computer Graphics International (CGI)},
  year = {2012},
  url = {http://viscg.uni-muenster.de/publications/2012/FH12},
}