Impostor-based animation of deformable virtual characters with dynamic shadow

Abstract

Modeling and animation of human is still a challenging research topic in computer graphics. Some systems can achieve real-time animation of numerous characters. However, the models are often very simple in appearance. On the other hand, some researches aim to generate photo-realistic animation of human model. Due to the complex computation involved, the refresh rate of the animation is low. This project aims to develop a realistic human modeling as well as a fast frame rate animation system. In order to achieve a high quality human model, various kinds of deformation that may happen in the human body are designed. The deformation of each body part is tailor-made to be anatomically correct while the model remains seamless. The deformations are applicable to common mesh human models and easy to control. A fast frame rate of animation can be maintained by using impostor. It is well known that impostor has the visibility problem, especially when animating numerous models. To correct the visibility problem, the depth information is incorporated to each model by using stencil buffer and bounding box. The experimental results show that the stencil buffer and bounding box provide a good correction to the visibility problem and still gain good improvement in the frame rate. For a scene rendered in geometry, the speed of animation is only 3 frames per second. 20 frames per second can be achieved by using the impostor. By using the stencil buffer and bounding box to correct the visibility problem, 11 frames per second can be achieved in our simulation. Finally, a shadow generation method for impostor rendering is proposed. Since the impostor will represent the 3D object as an image, the standard shadow generation method cannot be applied to render the impostor directly. We propose to reuse the stencil buffer and bounding box, which are already used in the correction of impostor visibility problem, for rendering impostor shadow using standard shadow mapping algorithm. Therefore, the impostor can cast or receive shadow to or from other objects. The shadowed impostor can also help to increase the frame rate to 11 frames per second, as compared to a frame rate of 4 frames per second obtained by rendering in geometry. In summary, our system can generate fast rate and high quality animation of numerous deformable human models. Our system can be applied to human crowd rendering, computer game applications, movie production, etc.

Date of Award	4 Oct 2004
Original language	English
Awarding Institution	City University of Hong Kong
Supervisor	Kwok Leung CHAN (Supervisor)