Interactive Character Deformation Using Simplified Elastic Models

Abstract

This thesis describes the results of our research into realistic skin and model deformation methods aimed at the field of character deformation and animation. The main contributions lie in the properties of our deformation scheme. Our approach preserves the volume of the deformed object while retaining shape details. Furthermore, we also consider interior dynamics such as muscles, which are key to producing realistic skin deformation. We model skin elasticity either by physically modeling and simulating the musculoskeletal system and the skin, or by minimizing an elastic energy constructed over a representation of the subject surface. We propose a number of simplifications so that we are able to produce plausible elastic deformations at interactive, or even real-time rates. As such, our methods are attractive to real-time graphics applications such as computer games. Based on scattered data interpolation and domain decomposition, we developed a space deformation method that supports localized, smooth, limb deformation changes. This method can be combined with the aforementioned methods for elastic deformation to deform the character skin. Finally, we present a novel rig control that can be easily combined with the elastic deformation methods in order to reduce the man effort of producing a skin animation. The rig control results from a deformation metaphor consisting of point handles that are controlled by the user. Based on this rig control, a new skinning scheme is obtained. Our preliminary results show its effectiveness at expanding the space of deformations provided by skeletal skinning.