In collaboration once again with Industrial Light & Magic, Hybride, a division of Ubisoft, produced a total of 50 undetectable VFX shots, including large-scale crowd simulations and a virtual replica of the Berlin stadium for the 1936 Olympic games, for Angelina Jolie’s epic drama, Unbroken.
"It was a great experience working with the entire team at Hybride. They were quick to pick up on the unique sensibility of the period "look" of Unbroken and also did their own research on the 1936 Berlin Olympics to make sure the work they were creating was historically accurate,” said Bill George, visual effects supervisor on Unbroken.
To shoot the sequence for the Olympics, an 8-foot stone wall was dressed at the base of a modern stadium in Sydney, Australia. Everything seen above this wall was created digitally by Hybride to extend the stadium. “The location was fairly empty,” noted Hybride visual effects supervisor Philippe Théroux. “On one side there were modern bleachers that had to be removed, and on the other side there were trees in the background, but no buildings. So we cleaned up all of that, and then added the stadium in CG. We did a lot of research to find original photography and footage of the stadium, and matched it. We modeled the correct architecture, textured it with the same stone used in the original stadium, and added details such as the giant clock on the pillar, the scoreboard, Hitler’s Nazi banners and Olympic flags. We then added features such as the big screen that displayed the names of the athletes and their times. We found pictures of those scoreboards and figured out how they worked—basically, they would spin little blocks around to write the names of the athletes backwards, which would be frontwards when seen from the outside. We re-created that, as well.”
The massive crowd of extras was shot live action, in period costumes, from a number of angles to populate the stands. “The creation of CG crowds is a complex technique than we’ve developed over several projects. Since no existing software allowed the flexibility we needed, we created a tool that would allow us to combine all kinds of variations, therefore avoiding a "cloning" effect,” explained Théroux.
Considering the stadium’s size and camera movements, the technique for creating the computer generated crowd varied according to each point of view. “Our crowd system is a lot easier to use than the crowd tools that are on the market. It allows us to use either a CG character or elements of people that have been shot against green screen,” said Théroux. “For example, in shots where the cameras were close to the crowd, we were afraid that using CG characters would look CG. So instead of creating digital characters, we went through all of the shots in the sequence and defined the various actions that would be needed in the crowd—people standing up, sitting down, applauding, waving flags, and so on. Then we shot 72 people in different costumes, performing all of those actions against green screen, from five different camera orientations, and from two different heights. We also did two different lighting conditions, depending on which side of the stadium those people would be sitting. We ended up with approximately 1,444 elements, which we cleaned up and introduced into our crowd system. 3D characters were also used in places where 2D cards were not practical.”
The size of the environment and camera movements made it impossible to use a green screen so most of the live action foreground plates had to be rotoscoped and integrated over the computer generated backgrounds. This technique allowed for greater speed and freedom in shooting the foreground action. A major design influence for the effects seen in Unbroken was the visual style established in the film by cinematographer Roger Deakins. The goal was to always have the effects shots fit seamlessly into the beautifully composted and lit shots that made up the live action portion of the film so tracking and layout work required the highest accuracy to be able to perfectly blend the CG elements, and final rendering of the shots needed to be done in accordance with the rest of film’s look and feel. “I was very impressed with their flexibility and responsiveness to changes as we moved through the creative process with the Director” said George. “Their strong production ability and focus on creative details makes it easy to trust that their work will be of the highest quality.”
Take a closer look at how our artists created the massive crowds and stadium replica here: http://www.artofvfx.com/?p=10826