'Gravity' Stereo Supervisor Reveals How 3D Was Used to Put Sandra Bullock in Space

Director Alfonso Cuaron told Chris Parks that he wanted "realistic 3D, the way that your eyes would see it."

To create the illusion that Sandra Bullock and George Clooney are floating in endless space, Gravity director Alfonso Cuaron used 3D -- and thanks to Cuaron and other filmmakers such as Ang Lee and Baz Luhrmann, audiences are starting to see more examples of the format's use as part of the storytelling and not as a gimmick.

In fact, in Gravity, there wasn't gratuitous use of objects popping out in front of the screen; rather, 3D was used to create the depth of space. In his own words, the director said he wanted "realistic 3D, the way that your eyes would see it."

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This was the mandate that Cuaron gave the film's stereo supervisor, Chris Parks (Jack the Giant Slayer, Pirates of the Caribbean: At World's End), who was brought onto the project more than a year before the team started principal photography.

"We talked about how his signature shots – [long takes during which] the camera moves around the subject -- could work fantastically well in 3D and about using wide-angle lenses to achieve the type of roundness and volume he was looking for," Parks tells The Hollywood Reporter. In fact, Cuaron made extensive use of long takes, including the first shot in the film that lasts 12 minutes before the first cut.

The use of wide-angle lenses throughout the shoot enabled Parks to pull elements into the theater space. These included sun flares, debris like a ballpoint pen, air bubbles and parts of the escape pods.

"We were able to make narrative use of 3D because Alfonso had integrated 3D with cinematography, visual effects and every other craft department from the outset," Parks says.

SPOILER ALERT: "For example, we deliberately floated a Marvin the Martian doll into the audience space using significant negative parallax (the space in front of the screen plane) to give a moment of light heartedness," he says. "This is designed to relax the audience's tension ahead of a whipped camera move as the characters come face to face with something dreadful (a dead body) inside the cockpit of the capsule. Rather than making that shocking moment the time when we bring the 3D out into the theater, a trick we felt would have been out of keeping with the story, we did something to alter the mood of the audience in the period immediately beforehand. That same emotion could not have been achieved in 2D."

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In 2010, when Robert Downey Jr. and Angelina Jolie were still attached to the project, the plan was to shoot the movie with a 3D camera rig. Says Parks: "I ran some tests with [director of photography] Emmanuel Lubezki using Arri Alexas on 3Ality rigs at Leavesden Studios to give Alfonso a taste for how 3D could enhance the feeling of weightlessness and how stereo could work with camera movement and lighting."

But to capture the fluidity of movement that Cuaron and Lubezki wanted, it eventually was decided to use robotic camera arms, for which the bulk and weight of the dual cameras on a 3D rig were unsuitable.

"There were several scenes that I would have loved to shoot natively, but at the end of the day, it was impossible to get the rigs into the confined shooting spaces or to support them on the robotic arms needed to get the zero-gravity feel," says Parks.

Instead, 25 minutes of the film, notably shots in the two capsules and the film's final shot, were lensed in 2D and went through a 2D-to-3D conversion at Prime Focus under Parks' supervision.

"Prime took the geometry of the escape pods from the scene, which gave us a pretty accurate foundation within which to put the characters," he says. "I also shot stereo reference plates of a moving model with different focal length lenses and different distances to demonstrate the sort of feel that I wanted to help me communicate with the conversion artists. From a 2D image alone, it can be surprisingly hard to create an accurate looking human. But with 3D shots for reference the team was able to judge, for example, how far the ears lie back from the forehead or the depth of an eye socket."

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The exterior scenes -- which mostly were CG -- were rendered in stereo in the computer at lead VFX house Framestore. In conjunction with Framestore and visual effects supervisor Tim Webber, Parks used a "virtual rig" and was able to manipulate the amount of depth per shot in similar manner to operating the interaxial distance between native stereo cameras.

Parks -- who is supervising the 3D on Doug Liman's Edge of Tomorrow -- likens native and postconverted stereo to the creative choice between special (in-camera) and visual (produced in the computer) effects.

"In some ways, post can never achieve what you can get from native or stereo-rendered 3D, particularly when it comes to shooting close-ups of human faces, but you will often get the best results and the best audience experience by putting both into play," he says.

"3D films have quite rightly received a lot of bad press," Parks adds. "There are very few worth seeing in 3D. The majority of 3D is not good since it doesn't add anything to the experience. The main thing I hope the audience will take away from Gravity is that good 3D can definitely enhance the experience.

"What is so vital to achieving that goal is that everybody involved in production needs to be onboard with 3D. Everyone has to be prepared to accommodate and achieve the ambition of creating fantastic 3D. That approach stems from the director. If the director's ambition is to create a great 3D experience, then everything from pre-viz to DI [digital intermediate] will be integrated to that make that happen."