Miguel A. Otaduy: Research

Topological Changes: Cutting and Fracture

The field of medical simulation has targeted numerous medical interventions that involve cutting of tissue; modeling by virtual carving and sculpting requires elementary operations that produce topological changes; and videogames and special effects for feature films often animate exploding and breaking objects. The simulation of cutting and fracture of deformable objects encompasses two main aspects: the geometric and topological aspect, concerned with the synthesis of crack surfaces and how these surfaces affect the discretization of the domain in the physically-based simulation; and the mechanical aspect, concerned with the computation of forces, deformations, and crack initiation and propagation.

The simulation of topological changes can be handled efficiently by separating the representations for the object surface and the material volume. A mesh-based surface representation allows for efficient detection of cracks and robust handling of boundary conditions. A meshless volume discretization, on the other hand, allows for efficient topological changes without complex remeshing [→]. Similar ideas can be applied to deformation models based on shape-matching [→]. But, when objects are cut or break, previously connected parts become disjoint and collide with each other. In order to efficiently simulate topological changes, it is also crucial to design collision detection data structures that address the particular problems in place [→].

Another interesting aspect associated with breaking objects is that fracture reveals their internal structure. Suddenly, the simulation must render previously inexistent surfaces, with unknown color and texture. Such surfaces can be modeled using solid texture synthesis techniques, combining the information from real photographs of cut objects [→].

Collaborators: Denis Steinemann (VirtaMed) [→], Nico Pietroni (CNR Pisa) [→], Markus Gross (ETH Zurich) [→].

Last modified June 10, 2009