Anais do IX SIBGRAPI'96 (1996), 265-272
Dynamic Animation of Elastic Bodies
Rogério L. W. Liesenfeld e Jorge Stolfi
Instituto de Computação - Unicamp
stolfi@dcc.unicamp.br
- Abstract:
-
We describe an animation system that simulates the dynamics
of viscoelastic bodies subject to equality and inequality
constraints. The equations of motion are derived from Lagrange's
equation, and constraint forces are computed by the method of Lagrange
multipliers. Each elastic body is modeled as a collection of
tetrahedral finite elements whose deformation is restricted to affine
transformations of their rest shapes. We use an original non-linear
formula for the elastic forces, especially devised to prevent elements
from collapsing to zero or negative volume. We also describe a
general algorithm to detect violation of inequality constraints. For
collisions, in particular, we use the optimization technique of Lin
and Manocha to cut the detection time from quadratic to almost linear.
Collisions are handled by temporary contact springs.
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