Evaluation of Real-Time Continuous Terrain Level of Detail Algorithms

In the world of 3D graphics many applications require the ability to render large 3D terrains in an efficient manner. To satisfy this need, algorithms have been devised that render height fields using a real-time continuous level of detail technique. Instead of drawing each of the many triangles that can make up a terrain, this technique renders the terrain with a highly reduced number of polygons at the expense of losing terrain accuracy. This project is an evaluation of three real-time continuous terrain level of detail algorithms described in the papers Real-Time Generation of Continuous Levels of Detail for Height Fields by [Röttger et al., 1998], ROAMing Terrain: Real-time Optimally Adapting Meshes by [Duchaineau et al., 1997] and Visualization of Large Terrains Made Easy by [Lindstrom and Pascucci, 2001]. The evaluation and comparison of the algorithms is based on the trade-off of polygon count to terrain accuracy over four separate test data sets. The results of this project show that the ROAM algorithm by [Duchaineau et al., 1997] almost always outperforms the other two algorithms. The one case where this algorithm is surpassed is when dealing with a very large, flat terrain. In this case, the algorithm by [Lindstrom and Pascucci, 2001] achieves the best terrain accuracy for a particularly low number of desired polygons, and the algorithm by [Röttger et al., 1998] displays the minimum number of polygons for a particularly high desired terrain accuracy.