'Deconstructing Gravity' Gives an Inside Look at Oscar-Winning VFX Technologies
An Academy panel provided a look at the unusual processes and technology that made the Alfonso Cuaron film possible.
The Oscar-winning hit Gravity was back on the big screen Monday night at the DGA – or, at least, portions of it were, in the form of a variety of finished and behind-the-scenes clips as part of an Academy of Motion Picture Arts and Sciences panel. The event, called "Deconstructing Gravity," was a look at the innovative technologies used to make the film.
The film represents a “landmark moment,” moderator and Academy governor and animator Bill Kroyer told The Hollywood Reporter prior to the panel. That’s because the film manages to be simultaneously an animated film, a live-action production and a VFX film – and because, in the words of director Alfonso Cuaron (as relayed by Kroyer), "we had to finish post-production before we could start pre-production."
By that, he meant that the entire film was pre-visualized – animated – before pre-production even started. Indeed, as Framestore VFX supervisor Tim Webber explained, even before pre-vis, the filmmakers used a rougher form of visualization referred to as pitch-vis to create rough sequences that were used to pitch the project. Since the film at that point had no financing, the pitch-vis was put together using models available at no cost on the Internet.
The pre-vis was more than just visual though: several of the filmmakers actually performed and recorded the entire script as part of the process, so that the dialog and intricate shots would work together properly. At one point, 20 animators were working on the pre-vis.
“We were blocking the movie in advance of filming,” said editor Mark Sanger, who was involved in the project from its earliest days. Sanger, Webber, Cuaron and others won Oscars for their work on the film, which won seven Academy Awards and was nominated for a total of ten.
The pre-vis was challenging even at the most basic level. Pixels and ink have no mass, but “animators are trained to portray weight,” said Webber. In the case of the perhaps-ironically named Gravity – set in a zero-G world – that required animators to do a mental reboot. “It’s breaking a lifetime habit,” he said.
Other technologies used in planning the film included models, physics simulations, motion capture and, prior to the pre-vis, traditional storyboards. As animation supervisor Max Solomon explained, yet another challenge was how to move the camera in order to "make [the film] feel more like a documentary, not sci-fi." In effect, he said, the camera was the third character in the film.
The pre-vis was not just used for planning purposes though. The metadata – such as position information regarding the lighting, characters and camera – was used to drive robots, lights, wire harnesses and other rigs during live action shooting itself. None of the shooting involved green screen. Instead, virtually everything but the actors’ faces and helmets was filled in later using CGI. In most cases, the boundary between live action and CGI was the edge of the helmet.
Even Sandra Bullock’s legs, visible when she sheds her spacesuit inside a space station, were the product of VFX artists.
Often, the actors performed inside a lightbox constructed of LED panels. (A smaller version of the lightbox was set up in the DGA lobby and was a crowd-pleaser.) When Bullock goes spinning off into space in a terrifying sequence early in the film, she was actually in a rig being moved around no more than 45 degrees off axis from vertical. The camera was moving too, but what was actually spinning were pre-vis images in the lightbox. Those images created realistic reflected light on the actress’s face and visor, and also gave her something to react to. “Without the pre-vis, she wouldn’t have known what she was supposed to do,” said Webber.
The early sequence in the film is also noteworthy because it’s a single shot, almost 12 minutes long, without an edit. And it’s not the only one: 17 shots make up 70 percent of the film, and the entire movie is about 350 shots, as contrasted with a more typical count of 2,000 shots for features.
But those shots aren’t actually as uninterrupted as they seem. In reality, they contain hidden edits, places where Sanger and his colleagues used a variety of tricks – morphs, racking focus, and more – to join separate shots but hide the seams.
The event was put on by the Academy’s Science and Technology Council, and was introduced by NASA astronaut Cady Coleman, who advised Bullock as she prepared for the film. Coleman kicked things off by saying “the hardest part of my job is that I get to go into space and other people don’t, [but] Gravity brought them to the place that they can’t go.”
And for those who wondered about the wizardry behind the screen, “Deconstructing Gravity” was likewise a journey to a place almost as magical as space itself.