US 5,793,371 A · Method and apparatus for geometric compression of three-dimensional graphics data

Abstract

In a compression system, three-dimensional geometry is first represented as a generalized triangle mesh, a data structure that allows each instance of a vertex in a linear stream to specify an average of two triangles. Individual positions, colors, and normals are quantized, preferably quantizing normals using a novel translation to non-rectilinear representation. A variable length compression is applied to individual positions, colors, and normals. The quantized values are then delta-compression encoded between neighbors, followed by a modified Huffman compression for positions and colors. A table-based approach is used for normals. Decompression reverses this process. The decompressed stream of triangle data may then be passed to a traditional rendering pipeline, where it is processed in full floating point accuracy.

Claims20

Dependent claims

A method for compression in which a three-dimensional object whose surface defines surface characteristics including at least one characteristic selected from the group consisting of (i) position, (ii) normals, (iii) colors, (iv) texture map coordinates, (v) material surface properties of said object, said object being representable as three-dimensional triangular data defining a plurality of triangles having vertices, the method comprising:

(a) converting said triangular data into linear strip format;
(b) quantizing individual ones of said surface characteristics;
(c) applying variable length compression to a difference between sequential ones said surface characteristics;
and
(d) providing a data stream representing said three-dimensional object as a collection of data generated in step (b) and step (c).

2 more elements

A system for compressing data representing a three-dimensional object whose surface defines surface characteristics including at least one characteristic selected from the group consisting of (i) position, (ii) normals, (iii) colors, (iv) texture map coordinates, (v) material surface properties of said object, said object being representable as three-dimensional triangular data defining a plurality of triangles having vertices, the system comprising:

a computer system including a central processing unit (CPU) and memory coupled to said CPU;
a first unit programmed to convert said triangular data into linear strip format;
a quantizing unit that quantizes individual ones of said surface characteristics;
a compression unit that applies variable length compression to a difference between sequential ones said surface characteristics;
and
a data stream generator that provides a data stream representing said three-dimensional object as a collection of data generated by said quantizing unit and by said compression unit.

3 more elements

Dependencies are inferred from the claim text.

Method and apparatus for geometric compression of three-dimensional graphics data

Life of this patent

Method and apparatus for geometric compression of three-dimensional graphics data

Life of this patent

Abstract

Claims20