Computer Graphics World

May/June 2014

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C G W M ay / Ju n e 2 014 ■ 15 VIDEO: Go to "Extras" in the May/June 2014 issue box .com .com ©2014 Disney The credibility of virtual humans, the possibility that CG actors could step in for real actors in more than wide shots, stunts, and brief glances, took a giant step forward when artists at Digital Domain created the character Benjamin Button for the movie of the same name and brought home a visual effects Oscar. Artists at that studio have continued pushing the technol- ogy and the process forward. Three pixies in Maleficent represent their latest efforts. "We built on the foundation we established with the facial animation, skin, and eye shader work on Benjamin Button and then Tron," says Kelly Port, visual effects super- visor at Digital Domain. "We took that to the next level. We had approximately 600 shots that made it into the film, but by far, [creating the pixies] was the place where we pushed the state of the art." Directed by Robert Stromberg and starring Angelina Jolie in the leading role, the film tells the story of Maleficent, the villain with a heart of stone in "Sleeping Beauty." (It's Maleficent who places the curse on newborn Aurora that will take effect on her 16 th birthday.) Carey Villegas was overall supervisor of the film, produced by The Moving Picture Company (MPC), Roth Films, and Walt Disney Pictures, and distributed by Disney Studios. In addition to Digital Domain, Method Studios, MPC, and The Senate provided visual effects, and The Third Floor did previs. Early in the film, when princess Aurora is born, the king asks the three little flower pixies – fairies – to take care of her and keep her safe. In the middle of the film, the pixies transform into humans. And then later, they become little pixies again. So, sometimes they are full-size humans played by live-action actors, but when they are only three feet tall, they are CG characters. Performance Capture Because the flower pixies would transform into actors later in the film, the actors drove the little fairies' performances, and each pixie resembled one of the actors: Imelda Staunton (Knotgrass), Juno Temple (Thistletwit), and Lesley Manville (Flittle). "The pixies are stylized versions of the actors," says Darren Hendler, digital effects supervisor. "Robert [Strom- berg] and Carey [Villegas] wanted photoreal characters that conveyed all the essence of the actors' performances. They are not animated creatures." Creating the stylized digital doubles was a multi-step process. The crews captured the actors' physical and facial performances, created CG models rigged to accommodate each actor's expressions, applied captured motion to the CG models, and textured, shaded, and lit the actors' faces. For the performances, the filmmakers brought the three actors and stunt actors to Digital Domain's virtual production studio where Gary Roberts supervised the motion capture. "We were able to do three face and body captures simultaneously with the stunt actors on rigs," Port says. "We used wishbone poles to move them around. So, we had six people in the capture volume while we were capturing the three helmet-cam setups. It was pretty involved." Each actor that was captured had two camera operators: one taking a wide shot and one taking tight shots. Six ad- ditional camera operators provided witness camera footage for wide and tight reference. Four cameras filmed the face. "We can analyze the black-and-white HD cameras from the helmet, but they have a really wide focal length and are a bit distorted," Port says. "It isn't the best for animators smoothing out facial capture. So, we also used cameras farther away and zoomed into the face." Pixie Style Before the team could apply the captured motion to the CG pixies, modelers and riggers needed to build the characters. "Traditionally, if we're just doing characters, we build the character first," Hendler says. "On this show, we built CG versions of the actors as our base so that our base was sound and really matched each actor." Thus, the artists created photoreal CG doubles for each actor early in the process, using a Light Stage system at USC's Institute for Creative Technologies (ICT) for high- resolution facial scans, and Gentle Giant for body and head scans. "Working with Paul Debevec, we got pore-level scans at ICT," Port says. "Those high-resolution scans for the base model were the best we've ever gotten." To accommodate facial expressions, the team had the ac- tors perform a set of FACS poses. Modelers and riggers used expressions captured in the FACS poses to sculpt shapes and design a system of control points for each pixie's face.

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