Issue link: https://digital.copcomm.com/i/77744
Invisible Effects n n n n "We extended the crowds digitally through a combination of elements shot against greenscreen and with a custom crowd sys- tem," Franklin says. "But, the key thing was the collapse of the stadium. I suggested that we do a miniature, knowing Chris likes that sort of thing, and miniatures worked well for us on Inception, but he felt that using a min- iature wouldn't be precise enough. The explo- sion starts slowly at the back and comes to the edge of a man running. So we went with a digital solution." The team at Double Negative built an entire CG stadium, including all the under- ground levels beneath the field. Then, using a combination of proprietary tools, Side Ef- fects' Houdini and Autodesk's Maya, they created a rolling, tightly choreographed wave of destruction. "The physics simulations were very complicated," Franklin says. "We used an awful lot of in-house solvers. The system was an evolution of the system we created for Inception to collapse the buildings by the seafront, but this was an order of magnitude more complicated. We had to show destruc- tion in a wide shot from the whole of the field, which was hundreds of yards wide, to literally five feet from the camera. The detail increased as the shot progressed. Then, we had to show it from multiple angles, as well." Thus, they couldn't create the simulation from one camera's view; they had to create a solution viewable from all angles. "We started by previsualizing the sequence," smoke, and building destruction, after an ex- plosion that happens toward the end of the film, using Houdini, Maya fluids, and the stu- dio's in-house fluid system, called Squirt. Mod- elers extended a massive prison set in a huge well. In addition, the team modeled, animated, and rendered a colony of bats. "They explode out of the well and startle Batman," Franklin says. "We re-created the same species that was in Batman Begins, the Egyptian free-tailed bat. But because they would be in IMAX resolu- tion, we added details." throughout the film, from vehicle, to build- ing, to fire and smoke, but this team had met the challenge before. "In terms of working on The need to add detail was consistent Franklin says. "Chris had always been skeptical about previs, but this time around, our previs team laid out the timing used to choreograph the stunts on the day. It was so complicated. We got all the department heads together and decided what would be stunts, what would be practical, what would be visual effects, and came to an agreement." The simulation artists also created the fire, A team from Double Negative captured HDRI images using a proprietary camera system with four SLRs. the film, it felt familiar because we've main- tained many of the same people since 2003," Franklin says. "This is our fourth film, so we had a real sense of continuity. On Dark Knight, we were feeling our way, working at this incredibly high resolution. But a lot of the people who came back for this film knew what we were getting into." Franklin believes the result of their com- bined experience has lifted the state of the art of visual effects once again. "We pushed the believability of our CG-generated en- vironments and vehicles," he says. "And, in daylight. They fit in seamlessly with photog- raphy. I think that was particularly extraordi- nary with the Bat and the stunts we replaced. When you watch the film, it looks like it was all shot for real, and that's the goal. Although computers have gotten faster, which makes dealing with the increased amount of data much easier, and software tools have gotten better, especially compositing and rendering tools, Franklin attributes the success of this film to the skills of the artists. "They've gotten better and better," Franklin says. "The tools get more powerful and faster, but it's the artists' skills that make the differ- ence. The people on our team fully understand the world that Chris tries to create with his films, and that produces astonishing results." n Barbara Robertson is an award-winning writer and a contributing editor for Computer Graphics World. She can be reached at BarbaraRR@comcast.net. June/July 2012 25