Real Steel: A New Virtual Production Paradigm
According to Digital Domain's Erik Nash, the production VFX supervisor, previs was achieved completely through real time interactive means in which Levy was in the ring with the boxing performers, directing them as he would human boxers, and then was able to come up with his camera moves in a very hands-on way.
"So heading to Detroit we brought the motion capture technology with us, but, unlike Avatar, we were putting our synthetic characters into the real world," Nash explains. "We were able to make the boxing robots visible to the camera operator and to Sean on his monitor. We now have plates that are photographed as if the robots are there.
"So the efficiency is huge, but, to me, the reason for taking this technology and pushing it to the next level was to attain a grittier and more visceral experience.
But the motion capture was only a foundation for the performance. Because of the two-foot scale difference between the real actors and the CG robots, all of the data prior to virtual camera and the Simulcam process in Detroit slowed down 10%. "We did that to help sell the weight, size and mass of the robots," Nash offers. And then once that data was turned over to the animators at DD, the process had several phases: to attain the robotic nature of the characters, they addressed the fidelity with which motion capture records all of the subtle nuances of human motion by developing tools to filter the MoCap data. Then there was a lot of keyframing to heighten the action and make some of the movement less fluid. There's always inaccuracy when you have two CG characters making contact with each other. Plus the MoCap actors didn't actually hit each other as hard as the CG robots needed to, so they sped up punches, hardened the punch impact and exaggerated the reactions.
"One of the biggest challenges was a result of the fact that three of the hero robots had practical onset animatronic versions built by Legacy," Nash explains. "That was great to have something physical for our robots to be intercut with."
Digital Domain used Vray at the renderer in conjunction with its lighting pipeline, creating more than a half-dozen prime robots. The toughest was the villain, Zeus, to fight the hero, Atom, because he was all-black and didn't have an animatronic counterpart.
"But our job wasn't done until you couldn't tell them apart," Nash concludes.
Bill Desowitz is former senior editor of AWN and editor of VFXWorld. He has a new blog, Immersed in Movies (www.billdesowitz.com), and is currently writing a book about the evolution of James Bond from Connery to Craig, scheduled for publication next year, which is the 50th anniversary of the franchise.