Fast Polyhedral Cell Sorting for Interactive Rendering of Unstructured
Grids
João Comba (Stanford University),
James Klosowsky (IBM T.J. Watson), Nelson Max (Lawrence Livermore
National Laboratory) , Joseph S. B. Mitchell (University at
Stony Brook, Cláudio
T. Silva (IBM T.J. Watson) and Peter L. Willians(Lawrence Livermore
National Laboratory)
Appears in the Proceedings of the 1999 Eurographics
Abstract:
Direct volume rendering based on projective methods works by
projecting, in visibility order, the polyhedral cells of a mesh
onto the image plane, and incrementally compositing the cell's
color and opacity into the final image. Crucial to this method
is the computation of a visibility ordering of the cells. If the
mesh is "well-behaved" (acyclic and convex), then the MPVO
method of Willians provides a very fast sorting algorithm;
however, this method only computes an approximate ordering in
general datasets, resulting in visual artifacts when rendered. A
recent method of Silva et al. removed the assumption that the
mesh is convex, by means of a sweep algorithm used in
conjunction with the MPVO method; their algorithm is
substantially faster than previous exact methods for general meshes.
In this paper we propose a new technique, which we call BSP-XMPVO,
which is based on a fast and simple way of using binary space
partitions on the boundary elements of the mesh to augment the
ordering produced by MPVO. Our results are shown to be orders
of magnitude better than previous exact methods of sorting cells.
Paper:
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comba@graphics.stanford.edu