The system uses a method of simulating low-viscosity fluids such as water and fire. Traditionally, computer graphic artists have used a series of blobs to represent water to varying degrees of success — they sometimes appear as unrealistic, grainy surfaces. Another popular method has been to employ a method called the “level set method,” which gives better surface representation, but does not render as well when broken down in smaller particles, such as a breaking wave.
The team’s innovative “particle level set method” uses a mix of particles and level sets, which allows artists to maintain smooth surfaces while still rendering the liquid when broken down. The rendering also uses an additional method to simulate how the water spray interacts with itself and the surrounding water, which results in more realistic representations.
Fedkiw explained that he does not design the graphics for the movies himself. Rather, along with the help of Rasmussen, Petterson and others from at the ILM, he designed a system that allows artists to create better water effects. Fedkiw’s research is focused on the design of new computational algorithms for a variety of purposes, such as computational fluid dynamics and solid mechanics, computer graphics, computer vision and computational biomechanics.
“The system is used for other things too, from motion capture to rendering, but I focus on physics-based simulation,” Fedkiw said.
The power of the system is evident in examples posted on Fedkiw’s Web site. He has included computer-generated clips of ocean waves crashing against a lighthouse, which produce huge and realistic sprays of water.
Fedkiw has worked on graphics and digital effects for approximately 20 movies.
“The most notable ones related to the award are the last two ‘Pirates of the Caribbean’ movies, the last ‘Harry Potter’ movie, ‘Evan Almighty’ and ‘Poseidon,’” he said. “I think the sinking ship shots in ‘Poseidon’ may be the best looking stuff.”
While Fedkiw expressed interest in working in the special effects industry, he said that if he switched careers full-time he would miss his academic pursuits too much.
“[I] would miss research with my Ph.D. students — it’s really fun. A lot of our research is on computer graphics too, so it’s synergistic with special effects.”
Fedkiw currently teaches CS205A: Mathematical Methods for Robotics, Vision and Graphics. Additionally, in spring quarter, he will teach a new class entitled CS205B: Mathematical Methods for Fluids, Solids and Interfaces.
“We have a great graphics group here at Stanford,” he said, “so taking some of those classes is a good start [to getting into the graphics industry].”
Two way coupled SPH and particle level set fluid simulation (with Frank Losasso, Jerry Talton and Nipun Kwatra).