Two-way coupling of rigid and deformable bodies
Proceedings of the 2008 ACM SIGGRAPH/Eurographics Symposium on Computer Animation
| Hi-index | 0.00 |
This thesis presents methods for the physically-based simulation of various solid and fluid phenomena, including coupled rigid and deformable bodies, multiphase incompressible flow, and rigid and deformable volumes or shells coupled to incompressible flows. First, we develop a hybrid deformable solid simulation framework for combining mesh-based and point-based representations of deformable solids. Kinematic relationships between sets of points or simulation objects are defined by introducing hard bindings, providing a variety of capabilities such as the simulation of meshes with T-junctions and improved collision resolution. Soft bindings are then introduced, allowing for additional degrees of freedom while using spring-like forces to target an underlying state. We further apply this framework to partially couple rigid and deformable bodies. We then develop a framework for the full two-way coupling of rigid and deformable bodies, which is achieved with both a unified time integration scheme as well as individual two-way coupled algorithms at each point of that scheme. Thus we do not require specialized methods for dealing with stability issues or interleaving parts of the simulation. We maintain the ability to treat the key desirable aspects of rigid bodies (e.g. contact, collision, stacking, and friction) and deformable bodies (e.g. arbitrary constitutive models, thin shells, and self-collisions). In addition, our simulation framework supports more advanced features such as proportional derivative controlled articulation between rigid bodies. This not only allows for the robust simulation of a number of new phenomena, but also directly lends itself to the design of deformable creatures with proportional derivative controlled articulated rigid skeletons that interact in a life-like way with their environment. Next, we extend the particle level set method for the geometric representation of three or more fluid regions. The method uses a separate level set function and a separate set of particles for each region. A novel projection algorithm is used to uniquely define the interface at any given point, providing a dictionary for translating the vector-valued multiple level set function into the standard single-valued level set representation. We use this method to simulate multiple interacting liquids with varying densities and viscosities, viscoelastic properties, surface tension forces and surface reactions such as combustion. Finally, we present a novel scheme for the two-way coupling of incompressible fluids and rigid or deformable volumetric solids or thin shells. The scheme uses an Eulerian representation for the fluid and a Lagrangian representation for the solid and enforces the no-slip boundary condition at the solid/fluid interface in a momentum conserving way. The coupling is treated implicitly, and the resulting linear system is symmetric indefinite.