Fast polyhedral cell sorting for interactive rendering of unstructured grids

Joao Comba, James T. Klosowski, Nelson Max, Joseph S B Mitchell, Claudio T. Silval, Peter L.williams

Research output: Contribution to journalConference articlepeer-review


Direct volume rendering based on protective 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-beliaved (acyclic and convex), then the MPVO method of Williams 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 ofSilva et al. removed the assumption tliat 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.

Original languageEnglish (US)
Pages (from-to)369-376
Number of pages8
JournalComputer Graphics Forum
Issue number3
StatePublished - 1999
EventProceedings of the 1999 20th Annual Conference of the European Association for Computer Graphics, EUROGRAPHICS '99 - Milano, Italy
Duration: Sep 7 1999Sep 11 1999


  • Depth ordering
  • Finite element methods
  • Scientific visualization
  • Visibility ordering
  • Volume rendering
  • Volume visualization

ASJC Scopus subject areas

  • Computer Graphics and Computer-Aided Design


Dive into the research topics of 'Fast polyhedral cell sorting for interactive rendering of unstructured grids'. Together they form a unique fingerprint.

Cite this