Technical Reports

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UBC CS TR-94-37 Summary

A Kinematic Model for Collision Response, July 13, 1994 Jason Harrison and David Forsey, 20 pages

One aspect of traditional 3D animation using clay or plasticine is the ease with which the object can be deformed. Animators take for granted the ability to interactively press complex objects together. In 3D computer animation, this ability is severely restricted and any improvement would drastically increase the range and style of animations that can be created within a production environment. This paper presents a simple, fast, geometric approach to controlling the nature, extent and timing of the surface deformations arising from the interpenetration of kinematically controlled animated objects. Rather than using dynamic simulations, which are difficult to configure, code, and control, the algorithm presented here formulates collision response kinematically by moving points on a multiresolution surface towards goal points at a certain rate. This new multi-resolution approach to deformation provides control over the response of the surface using a small number of parameters that determine how each level in the multi-resolution representation of the surface reacts to the interpenetration. The deformations are calculated in linear time and space proportional to the number of points used to define the surface.

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