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Motion Capture n n n n directors want to concentrate on the action," says Casey Schatz, previsualization supervisor at Giant. "And, it's crucial to get the motion capture perfect. We didn't want Shawn [Levy] worrying about camera angles." Camera an- gles would happen later. After the capture sessions, Giant applied the data to Digital Domain's robots, and Levy picked the performances he liked. "Sometimes he liked the performance from one take," Schatz says. "But sometimes he liked the first half of one fight and the second half of an- other, so we would stitch the parts together." Giant also adjusted the motion as needed to give Levy the performances he wanted. "The 'bots are superhuman, and sometimes the stunt actors weren't capable of doing the actions Shawn [Levy] wanted," Madden says. "We might speed up a punch cycle to give the robot a hyper-drive move. Or, layer additional motion when a robot jumped across the ring so it didn't look like he was on a pulley system. This allowed Shawn to bring the actions closer to final performances so he could explore the camera angles he wanted for final shots." Camera Capture Once the crew at Giant knew which perfor- mances Levy wanted, they applied the data to Digital Domain's low-res robots, placed the ro- ment. The structures were accurate, and we lit it close to the final lighting. He wanted it to be as seamless as it could be on location." Exactly what Levy saw on the Giant stage through his virtual camera depended on the camera lens and camera angles he chose. Schatz had made sure that the virtual camera had the same lens kit that the cinematogra- pher would use later. "Shawn [Levy] would move around the stage holding the device, and he could see what I streamed from MotionBuilder, the robots, and the environments through the [virtual] lens," Schatz explains. "He might say, 'Put on a 35mm camera,' and I'd change the lens. He drove the camera. If he did a take and didn't like it, we wouldn't save the data. When he got a take he loved, we'd dump it into the cut." Giant had an Avid system on site, and Levy's editor was there on the days they cap- tured the camera to assemble into a cut the shots Levy liked. "The cut would grow organi- cally," Schatz says. "We started with the first shot, put it in the Avid, and then the second shot." At lunchtime, Levy would look at the assembled edit to see whether the progression worked in the way he had in mind. If not, he could go back to the stage to, perhaps, change a camera angle. "Covering a fight can be difficult," Madden multiple revisions in real time," says Digital Domain's Gillberg. "It was a refined, advanced previs that we used as a very appropriate guide for principal photography." At the end of a week, the team had the shots locked down. On location, everyone knew which lens Levy wanted for each frame and every fight beat. In addition to the previs, Schatz created a PDF for every shot that showed the camera's placement, field of view, how fast it was mov- ing, and a time-code range. "The PDF also had the subject distance and height," Schatz says. "It even showed the seating area to help Nash and the assistant director move the ex- tras around and schedule the shots." With all these fight specifics in a database, the crew could sort and organize shots based on the type of camera, where the camera was looking, and how many extras were visible. "We could be extremely efficient," Nash says. "By organizing the shots in groups by lens and camera rather than in continuity, it made shooting the plates incredibly time efficient." The previs also helped the actors and extras during principal photography, which took place from June through September 2010. Although the camera operator would see the CG robots during filming, the actors and extras needed to react to fights they couldn't see. "We cued up the fight on the day so the bots into environments created by Digital Do- main and at Giant from art department plans. Then, they handed Levy a virtual camera. The virtual camera, a tablet-like device, had mo- tion-capture markers on it so the crew at Gi- ant could track it in much the same way they had tracked the stunt actors' perfor mances. Levy held the "camera" on the motion-capture stage. On the display, he could see the CG robots—boxing with the performances he had selected and properly scaled in CG environ- ments that matched the locations and sets in which he would later film. "We even put crowds in the arena," Mad- den says. "They were static, but it gave the director a real-time version of the environ- Above left, Giant captured stunt actors in motion-capture suits at its studio for the virtual boxers who performed in the rings. Above right, stunt actors wearing IBC (image-based capture) "jammies" performed the robots' actions outside the ring while standing on stilts to give actor Hugh Jackman a proper eye line. says. "It's so fast paced. There is frenetic move- ment with the camera. This session allowed us to create a realistic cut of the fights with game- level CG graphics and resolution. The timing of the action and the timing of the camera movement were close to the final result." Extreme Previs, Extreme Shoot It was, in fact, an extreme form of previs. Di- rected by Levy, the previs included sequences representing all the robot fights. "The edit had good mocap motion, accurate backgrounds, and the director had the opportunity to do actors could see it, and we also had the robot performers there on stilts as reference for the ac- tors," Madden says. "The performers knew the moves and re-created them as best they could as a run-through so the crowd knew what would happen. They would understand what it meant later when someone held out a tennis ball." When filming began, the crew would use a Simulcam process for the real-time compos- iting, with Giant and Glenn Derry's Video Hawks installing an evolution of the system used for Avatar. To make this possible, before principal photography, Digital Domain and October/November 2011 21

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