Animating Explosions

Wednesday, October 8, 2003 - 17:30
TH 331
Prof. James O'Brien U.C. Berkeley, EECS Dept.

A suspended particle, or dust, explosion occurs when a flammable particulate, such as gunpowder or coal dust, is dispersed over a volume of air and then ignited. The behavior of the resulting explosion is determined by the non-linear, numerically stiff equations that govern compressible fluids. These equations give rise to the explosion's blast wave, and they shape the clouds of flame generated by the burning particles. However, solving these equations for explosive conditions is both algorithmically difficult and computationally expensive. The method that my students and I have developed models the large scale motion of the flame and smoke without explicitly modeling the transient behavior of the numerically troublesome blast wave. We accomplish this by directly manipulating an incompressible fluid field to generate appropriate expansive outflow in a fashion that is completely stable even at very large time integration steps. This method captures the visually important aspects of an explosion while ignoring visually irrelevant aspects that would have been expensive to compute. Using this method we can, in only a few minutes, compute realistic looking results that would previously have required days.


James F. O'Brien is an Assistant Professor of Computer Science at the University of California, Berkeley. His primary area of interest is Computer Animation, with an emphasis on generating realistic motion using physically based simulation and motion capture techniques. He received his Ph.D. in Computer Science from the Georgia Institute of Technology. James has authored numerous papers, including eight presented at the ACM SIGGRAPH conference, and his work has been featured multiple times in the SIGGRAPH Electronic Theater. He has been the recipient of several awards, most recently a research grant from the Okawa Foundation.