The Hong Kong University of Science and Technology
Department of Computer Science


PhD Thesis Defence


"High Performance Virtual Clothing Dynamics"

By

Mr. Sai-Keung Wong


Abstract

There are three major problems in modeling the natural motion of virtual
clothing in a 3D environment: (1) a very large number of contact points,
(2) the computations of collision information in the presence of numerical
errors, and (3) friction, stiction and dynamic response in the presence of
objects with sharp features. This thesis proposes new techniques that
successfully address these three major problems. The results show that
these new techniques can be applied on virtual garments with complex
geometry and on unique interactions between continuous and non-smooth
surfaces. Our techniques are classified into four categories: (1) culling
non-colliding subsurfaces during collision detection, (2) intrinsic
collision detection, (3) collision response, and (4) the editing and
animation of special virtual garments.

For culling non-colliding subsurfaces during collision detection, we
propose an image-based method for interference test, a method of
decomposition of a surface into a new type of (B, I)-surfaces for exact
collision detection in the time domain and an adaptive backward
voxel-based (BVOX) hierarchical structure for dealing with highly
compressed deformable surfaces.

For intrinsic collision detection, we propose a new system architecture.
Robust treatments of numerical errors are devised.

For collision response, a penetration-free motion space is proposed for
handling features involved in multiple collision events and a static
analysis method is suggested for handling friction and stiction.
Interactions with objects having sharp feature are handled correctly.

For the editing and animation of special virtual garments, we propose
techniques to handle multi-layered surfaces, surfaces with sharp features
and sewn surfaces. A multi-layered surface is constructed by gluing
several surfaces together either along lines or over regions. A surface
with sharp features is represented by two meshes. A sewn surface is
obtained by systematically performing a stable sewing process.

These techniques have been integrated into a high performance system for
clothing dynamics. Although our focus is on virtual clothes, the
techniques can be applied to other kinds of deformable surfaces, for
example, rubber and skin.


Date:			Friday, 3 December 2004

Time:			2:30p.m.-4:30p.m.

Venue:			Room 4480
			Lifts 25-26

Chairman:		Prof Man Yu Wong (MATH)

Committee Members:	Prof. George Baciu (Supervisor)
			Prof. Andrew Horner (Supervisor)
			Prof. Siu-Wing Cheng
			Prof. Chi-Keung Tang
			Prof. Matthew Yuen (MECH)
			Prof. Enhua Wu (Comp. & Inf. Sci., Univ. of Macau)


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