filename:       309
entry:          techreport

title:          Interactive Cuts through 3-Dimensional soft Tissue
author:         Daniel Bielser, Volker A. Maiwald and Markus H. Gross
address:        Institute of Scientific Computing
month:          December
year:           1998
keywords:       Physically Based Modeling, Surgery Simulation, Soft Tissue
language:       English
pages:          8
institution:    ETH Zürich

abstract: 

We describe a physically based framework for real-time modeling
and interactive cutting of 3-dimensional soft tissue that can be
used for surgery simulation. Unlike existing approaches which are 
mostly designed for tensorproduct grids our methods operate on 
tetrahedral decompositions giving more topological and geometric 
flexibility for the efficient modeling of complex anatomical 
structures. We start from an initial tetrahedralization such as 
being provided by any conventional meshing method. In order to 
track topological changes tetrahedra intersected by the virtual 
scalpel are split into substructures whose connectivity follows 
the trajectory of the cut, which can be arbitrary. For the efficient 
computation of collisions between the scalpel and individual tetrahedra 
we devised a local collision detection algorithm. The underlying 
physics is approximated through masses and springs attached to each 
tetrahedral vertex and edge. A hierarchical Runge-Kutta iteration 
computes the relaxation of the system by traversing the designed data 
structures in a breadth-first order. The framework includes a force-
feedback interface and uses real-time texture mapping to enhance the 
visual realism.