Modelling Techniques

Abstract

Currently, most of the existing deformation methods are fully built on an elastic model. However, the behaviours of soft objects such as human tissues are extremely nonlinear. The common deformation methods, such as mass-spring methods, finite element methods and boundary element methods, are mainly based on linear elastic models because of the simplicity of linear elastic models and also because linear elastic models permit to reduce runtime computation. However, linear elastic models cannot accommodate large-range geometric deformations. Although the few methods which can handle the large-range deformations, the use of quadric strains generally causes a very expensive computation for realtime simulation. In addition, extra work often needs to be performed for anisotropic deformations. This paper presents a new methodology for deformable object simulation by drawing an analogy between reaction-diffusion and elastic deformation. The potential energy stored in an elastic body as a result of a deformation caused by an external force is propagated among mass points by the principle of reaction-diffusion. An improved reaction-diffusion model is developed for propagating the energy generated by the external force among mass points. A method is presented to derive the internal forces from the potential energy distribution.