Geometry compression

Abstract

This paper introduces the concept of Geometry Compression, lowing 3D triangle data to be represented with a factor of 6 to times fewer bits than conventional techniques, with only slight los es in object quality. The technique is amenable to rapid decomp sion in both software and hardware implementations; if 3D rend ing hardware contains a geometry decompression unit, applicat geometry can be stored in memory in compressed format. Geo try is first represented as a generalized triangle mesh, a data s ture that allows each instance of a vertex in a linear stream to sp ify an average of two triangles. Then a variable length compress is applied to individual positions, colors, and normals. Delta com pression followed by a modified Huffman compression is used f positions and colors; a novel table-based approach is used for mals. The table allows any useful normal to be represented by 18-bit index, many normals can be represented with index deltas 8 bits or less. Geometry compression is a general space-time tr off, and offers advantages at every level of the memory/interco nect hierarchy: less storage space is needed on disk, less trans sion time is needed on networks.