A Unified Lagrangian Approach to Solid-Fluid Animation

Abstract

We present a framework for physics-based animation of deforming solids and fluids. By merging the equations of solid mechanics with the Navier-Stokes equations using a particle-based Lagrangian approach, we are able to employ a unified method to animate both solids and fluids as well as phase transitions. Central to our framework is a hybrid implicit-explicit surface generation approach which is capable of representing fine surface detail as well as handling topological changes in interactive time for moderately complex objects. The generated surface is represented by oriented point samples which adapt to the new position of the particles by minimizing the potential energy of the surface subject to geometric constraints.We illustrate our algorithm on a variety of examples ranging from stiff elastic and plasto-elastic materials to fluids with variable viscosity.