Geometry videos: a new representation for three-dimentional animations

Animations of three-dimensional computer graphics are becoming an increasingly prevalent medium for communication. There are many sources of 3D animations including physical simulations, scientific visualizations, and classic key-frame animations generated by an artist. There are even computer vision systems available today that are capable of capturing 3D time-varying geometric models. In this research, we develop a new representation for an important class of 3D animations, specifically time-varying manifolds. We call this representation a “Geometry Video.” At present, a viewer of a 3D animation must either have a similar simulation or animation infrastructure to the animation's producer, or the producer must create a video from a predefined set of viewpoints. Geometry videos provide the ability to encode and transmit a time-varying mesh in a generic, source-independent, and view-independent format. Geometry videos are created by constructing a global two-dimensional parametrization of a manifold over a rectangular domain. Time sequences of such parametrizations are particularly well-suited to compression using methods akin to video compression. This dissertation develops the techniques necessary to encode and compress arbitrary 3D manifold animations. A system is presented for converting animations into geometry videos as well as compressing and decompressing such representations. We also discusses the problems, design-parameters, and trade-offs associated with building such a system. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)