Real-time rendering of deformable parametric free-form surfaces

Deformable objects are required to improve the realism of virtual reality applications. They are particularly useful in modeling clothes, facial expression, human and animal characters. A common method to render these objects is by tessellation. However, the tessellation process is computationally very expensive. If the object deforms, we need to retessellate the surface every frame, as its shape changes from one frame to the next. This computational burden poses a significant challenge to the real-time rendering of deformable objects. Consequently, deformable objects are seldom incorporated in existing virtual reality systems. In this paper, we present an incremental method for rendering deformable objects modeled by parametric free-form surfaces. We also introduce two new frame coherence techniques for crack prevention and parameter caching. Finally, we present a single hierarchical data structure which provides a multi-resolution representation of the object model. © 1999 ACM