[Colloquium] REMINDER: Wednesday's talk by ByungMoon Kim

[Margery Ishmael]

DEPARTMENT OF COMPUTER SCIENCE - TALK REMINDER

Date: Wednesday, April 25, 2007
Time: 2:30 p.m.
Place: Ryerson 251 (1100 E. 58th St.)

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Speaker: ByungMoon Kim from Georgia Institute of Technology

Web page:  http://www-static.cc.gatech.edu/~bmkim/

Title: Scientific Computing for Fluid Animation

Abstract:
Recent advances in simulation methods for three-dimensional
computer animation have led to a significant increase in
realism and have benefited the digital entertainment industry.
We will discuss two methods for improving the realism in fluid
simulations: (1) The improved BFECC advection that increases
the dynamic in simulated fluid motion and (2) a volume control
technique that prevent the loss of volume in gas bubbles.
We will demonstrate these advances on simulations of smoke,
liquid, bubbles, rigid bodies, and foam. More detailed summaries
of these two methods are provided below. We will also discuss
future opportunities afforded by the symbiotic relation
between scientific computing and computer animations.

Copies of the papers and videos of the animations may be accessed from:
http://www-static.cc.gatech.edu/~bmkim/all_publications.htm

The BFECC (Back and Forth Error Compensation and Correction) was
recently developed for interface computation using a level set method.
We show that BFECC can be applied to reduce dissipation and diffusion
encountered in a variety of advection steps, such as velocity, smoke
density, and image advections on uniform and adaptive grids and on a
triangulated surface.  BFECC can be implemented trivially as a small
modification of the first-order upwind or semi-Lagrangian integration
of advection equations. It provides second-order accuracy in both
space and time. When applied to level set evolution, BFECC reduces
volume loss significantly. We demonstrate the benefits of this
approach on image advection and on the simulation of smoke, bubbles in
water, and the highly dynamic interaction between water, a solid, and
air. We also apply BFECC to dye advection to visualize vector fields.

Liquid and gas interactions often contain bubbles that stay for a long
time without bursting on the surface, making a dry foam structure.
Such long lasting bubbles simulated by the level set method
can suffer from a slow but steady volume error that accumulates to a
visible amount of volume change. We propose to address this problem by
using the volume control method. We trace the volume change of each
connected region, and apply a carefully computed divergence that
compensates undesired volume changes. To compute the divergence, we
construct a mathematical model of the volume change, choose control
strategies that regulate the modeled volume error, and establish
methods to compute the control gains that provide robust and fast
reduction of the volume error, and (if desired) the control of how the
volume changes over time.

***The talk will be followed by refreshments in Ryerson 255***

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Hosts: Todd Dupont and John Reppy

People in need of assistance should call 773-834-8977 in advance.

For information on future CS talks: http://www.cs.uchicago.edu/events


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