Fast Ray Traversal of Unstructured Volume Data using Plucker Tests

Gerd Marmitt, and Philipp Slusallek
Technical Report 2005-01, April, submitted for publication
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The importance of high-performance rendering of unstructured data sets has increased significantly mainly due to its use in scientific simulations such as computational fluid dynamics and finite element computations. However, the unstructured nature of these data sets complicate their handling and lead to low performance even with hardware support through GPUs.

In this paper, we present a new two-step interactive rendering approach for unstructured tetrahedral grids using ray tracing. The first tetrahedron along a ray is found using common techniques from realtime ray tracing. We then continue traversing the volume using a fast Pluecker test to select the next tetrahedra from the set of neighbors. The new traversal algorithm achieves interactive performance with simple shading on medium size data sets and scales linearly in a distributed setup. Since the volume is rendered directly, it is applicable for rendering isosurfaces as well as emission-absorption models.