Semi-Realistic Balloon Simulation

This paper describes a technique to accurately simulate a balloon expanding and bursting. Physical simulation is achieved through use of a spring-damper model with point masses to represent the surface of the balloon. Visual characteristics of the balloon, such as variable opacity and variable shininess are also addressed by this approach using material attributes in the SGI lighting model. Spring constants are user-de nable as a function of height and internal pressure of the balloon is also controlled by the user. Bursting is achieved by using spring thresholds which allow for fractures in the surface and lead to a chain reaction of spring failures. Balloon models can be created in a 3D sculpting program by an isosurface algorithm and can be used by the simulation. By using physically based modeling techniques, the problem can be simpli ed and easily implemented using a few simple data structures. To maintain simplicity and minimize elapsed time between frames, collision detection will not be implemented in this model. By using SGI graphics hardware to render the balloon, interactive rates can be achieved for simple balloon models, however, more complex balloons will result in longer delays between frames.