| Summary: | This thesis presents a biomechanically based hand simulator. We make
contributions at two di erent levels: hand motion and hand appearance.
We rst develop a musculotendon simulator, and apply this simulator to
an anatomically based hand model. Anatomically based hand simulation is
challenging because the tendon network of the hand is complicated and it
is highly constrained by the skeleton of the hand. Our simulator employs
the elegance of the Eulerian-Lagrangian strand algorithm, and introduces
a 2D planar collision approach to e ciently eliminate unnecessary degrees
of freedom and constraints. We show that with our method, we obtain the
coupling between joints automatically, and achieve the storage of energy in
tendons for fast movements. Also, by injuring a tendon, we are able to
obtain simulations of common nger deformities.
Although the musculotendon based hand simulation produces natural
hand motion, hand animation is usually observed at the skin level. We
present a novel approach to simulate thin hyperelastic skin. Real human
skin is a thin tissue which can stretch and slide over underlying body structures
such as muscles, bones, and tendons, revealing rich details of a moving
character. Simulating such skin is challenging because it is in close contact
with the body and shares its geometry. We propose a novel Eulerian representation
of skin that avoids all the di culties of constraining the skin to lie
on the body surface by working directly on the surface itself. Skin is modeled
as a 2D hyperelastic membrane with arbitrary topology, which makes it easy
to cover an entire character or object. We use triangular meshes to model
body and skin geometry. The method is easy to implement, and can use low
resolution meshes to animate high resolution details stored in texture-like
maps. Skin movement is driven by the animation of body shape prescribed
by an artist or by another simulation, and so it can be easily added as a
post-processing stage to an existing animation pipeline. We demonstrate
realistic animations of the skin on the hand using this approach. We also
extend it to simulate other parts of human and animal skin, and skin-tight
clothes. === Science, Faculty of === Computer Science, Department of === Graduate
|
|---|
