Weight maps helped make that movement believable. “We painted weight maps – grayscale texture maps – to define range of movement,” says Breakspear. The weight maps controlled how much influence each dot had over the geometry. “The skin on the nose doesn’t move far, so the weight map would be tight there,” explains Breakspear. “But a weight map for the cheek would be squashy.” Thus, if an anomalous dot tried to stray from reality, the weight maps pinned it in place.
The result gave them fully CG versions of the actors’ faces performing as they did on set. “It was a breakthrough,” says Breakspear of the team’s solution. “A eureka moment.”
Getting the Texture
After a final cleanup of the performance using hands-on animation — a tweak to animate the lips or the eyes a bit more, perhaps — the effects artists began texturing the faces. “We had textures captured at 24 frames per second that matched the performance we captured,” says Sabourin, “So we applied those animated textures to the mesh.” To tidy the textures and remove the tracking markers, the artists used Eyeon Software’s Digital Fusion, Right Hemisphere’s Deep Paint, and Adobe’s Photoshop.
Then, especially for close-up shots, they extracted high-resolution displacement maps from the XYZ RGB scans to add such details as scars and pores. “That, combined with the animated texture maps, gave us wrinkles,” says Sabourin. “Because we had 150 face replacements with unique performances to do, we gave the faces that were far away only the bare minimum, but a lot of the shots were close-ups.”
To match the lighting on the digital face to lights used when filming the skating doubles, Breakspear relied on HDRI. “For every shot of the doubles, we had shots of a gray ball, a chrome ball, and images taken with a fish eye camera,” he says. Even so, the lighting team faced unique challenges. “The ice created a big bouncing light environment. Our lighting team did a fantastic job making the digital faces look right.” For rendering, Rainmaker used Mental Ray.
Crowd Control
In addition to the facelifts for the skaters, Rainmaker also did digital surgery on the LA sports arena where the directors shot all live-action footage, but all the action in the film takes place in three other skating rinks in three different locations.
“Creating full CG stadium replacements with CG crowds was roughly half our work,” says Breakspear. Although the studio had devised a method to create crowds in 2D for the film She’s the Man [see F&V's coverage here], the camera moves needed for the swirling skating sequences dictated a 3D solution.
During the live-action shoot, 800 people and 5000 inflatable stuffies sat in the stands. “The stuffies worked well for a blurring background,” says Breakspear. “They look like real people. But in some shots we needed to have the people moving and clapping.”
For those shots, Rainmaker either replaced everything in the L.A. arena from the second level of seats up or created fully 3D stadiums by building digital sets in Maya. For the crowds, the studio used Massive software, building brains that signaled the fans to clap, cheer, stand up, sit down, walk through the aisles, and even order hot dogs. The CG characters moved using animation cycles created from motion data captured at the studio’s new division, Mainframe Entertainment, which Rainmaker acquired during 2006.
Beware of the 'Iron Lotus'
The climax of the film revolves around the “Iron Lotus,” a secret move never before successfully performed, that the characters played by Farrell and Heder try in front of a crowd of 15,000 screaming fans. “It has never been performed before because if a skater gets it one percent wrong, it could decapitate him,” says Breakspear. “We dreamed up this move during previz. When we explained it to our professional skating doubles, they wouldn’t speak to me for a week. They were teasing me. We all had a good laugh making it.”
Creating the Iron Lotus moves for the film involved face replacements, rig removals, CG crowds, CG stadiums, and green-screen composites. “Everything came together,” says Breakspear. “It was so dramatic. John Heder grabs Will’s leg and throws him in the air. Will spins in the air backwards. Then, John puts one leg in the air, does his own spin and jumps into the air ... and ... it’s so dramatic.”
That people walk out of the theater laughing, not wondering how the actors could possibly have performed their skating moves is a tribute to the VFX moves performed at Rainmaker. “Without our new face-replacement technology, we couldn’t have done it,” says Breakspear.
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