Interactive dynamics

Abstract

Our goal is to use physical simulation as an interactive medium for building and manipulating a wide range of models. A key to achieving this goal is the ability to create complex physical models dynamically by snapping simple pieces together, integrating the process of model creation into the ongoing simulation. We present a mathematical and computational formulation for constrained dynamics that makes this possible, allowing encapsulated objects, constraints, and forces to be combined dynamically and simulated efficiently. The formulation handles arbitrary objects, including nonrigid bodies. We describe an implementation for interactive dynamics, and discuss applications to mechanism construction, geometric modeling, interactive optimization data fitting, and animation.