Shape Deformation Using a Skeleton to Drive Simplex Transformations

This paper presents a novel skeleton-based method for deforming meshes (using an approximate skeleton, rather than a precise medial axis). The significant difference from previous skeleton-based methods is that the latter use the skeleton to control movement of vertices whereas we use it to control the simplices defining the model. By doing so, errors that occur near joints in other methods can be spread over the whole mesh, using an optimization process, resulting in smooth transitions near joints of the skeleton. By controlling simplices, our method has the advantage that no vertex weights need to be defined on the bones, which is a tedious requirement in previous skeleton-based methods. Our method can also easily be extended to control deformation by moving a few chosen line segments or vertices embedded in the object, rather than a skeleton.

1 Introduction

Mesh deformation is widely used in computer animation and computer modeling to represent moving objects of changing shape. Many techniques have been developed to help artists sculpt stylized body shapes and corresponding deformations for 2D and 3D characters, for example. These techniques include free-form deformation (FFD), multiresolution approaches, differential methods, and skeleton-based methods.