Haptic subdivision: an approach to defining level-of-detail in haptic rendering

Soft objects are often desired in applications such as virtual surgery training. Soft object simulations are computationally intensive because object deformation involves numerically solving a large number of differential equations. However, realistic force feedback requires deformation be computed fast and graphic feedback requires deformation be highly detailed. In this paper, we propose an approach that balances these requirements by subdividing the area of interest on a relatively coarse mesh model. Thus we keep the number of nodes of the model under control so that the simulation can be run at a sufficiently high rate for force feedback. The model we use is based on a mass-spring model. When a portion of the surface is subdivided, new values of mass and spring constants are determined such that computed force feedback offers the user the same reaction force as before subdivision.