Bounding volumes are used to optimize many graphic algorithms. They permit to decide quickly if a more exact test is likely to succeed or not. The exact test is only applied if the bounding volume test succeeds, which saves time in most cases. Two of the most prominent applications are ray tracing and collision detection.
This paper presents a new method to calculate tight bounding volumes for primitives under arbitrary transformations and hierarchical scene descriptions. An optimized form of storing a convex hull is presented which allows efficient calculation of the bounding volume type used for later processing. Results are shown for the ray tracing of cyclic CSG-graphs used to render plants and other natural phenomena.