Playing a Role
By Barbara Robertson
August 17, 2010

Playing a Role

CIS Vancouver peppers Salt with delicious environmental effects

    The spy thriller Salt from Sony Pictures spices the action with a conundrum: Is the character Angelina Jolie, who plays a Russian spy, a CIA agent or both? Accused of the former while working for the latter, Evelyn Salt, the character, goes on the run, handing Jolie numerous opportunities for exercising her action-hero skills. Two visual effects studios helped her evade the wannabe captors: Framestore and CIS Vancouver.

     “Angelina does her own stunts,” says Mark Breakspear, visual effects supervisor at CIS. “She was one of the hardest working people on the crew. For a freeway sequence where she jumps out of a car and onto a truck, and jumps from one truck, to another, to a car, she was on wires, but she did the stunts herself. She worked so hard; I was really impressed.”

 Framestore handled effects for truck sequence, Breakspear explains. “They added CG cars in the background and made a New Jersey turnpike look like Washington DC,” he says. “It was a very cool, good sequence. Ivan [Moran] and his crew did a great job. The sequence is definitely part of this movie in a big way.”

     For his part, Breakspear led a crew at CIS that worked on approximately 300 shots. Although the biggest number of those involved enhancing fight sequences with guns and gunfire, from a visual effects standpoint, the most interesting were two sequences involving complex environments. In one, Salt jumps from side to side down the length of an elevator shaft, even though Jolie performed the stunt on a small set. In another, Salt’s captors pull her into a Black Hawk helicopter on the south lawn of the White House, even though director Phillip Noyce filmed Jolie on Long Island.
Going Down

    For the elevator shaft sequence, the set designer built a two-story elevator shaft large enough to hold Jolie and a cameraman, both attached to rigs, and placed bluescreen at the top and base. In the story, the president has run into an elevator, intending to take it eight stories down to a bunker, and closes the doors behind him. Salt pries open the doors and jumps down the shaft to catch the elevator car.

     “The original plan was that we would extend the practical set,” Breakspear says. “We never thought we’d build an entire background.”

     Starting with a 3D scan of the set, they added the eight floors called for in the script, and then realized that wasn’t enough. “With only eight floors, the stunt looked like something my grandfather could do,” Breakspear says. “So we added eight floors above and eight floors below. When the camera looked up, we’d have the roof get farther and farther away.”

     But, the shot still didn’t quite work. One problem was that the rope Jolie hung onto took some of her weight. “When we removed the rope, it looked like she was floating a bit,” Breakspear says. “We’d put all this effort into extending the elevator shaft and the shot just wasn’t happening. There was some thought about cutting the shots out. We weren’t sure what to do.”

To make Angelina Jolie’s stunt work look more dramatic, the visual
effects artists at CIS Hollywood replaced an elevator shaft set with a
digital replica that they moved rapidly past her rotoscoped images.

But, Robert Grasmere, the overall visual effects supervisor, challenged the CIS crew to make the stunt more dramatic. “He sent all the material shot on set to CIS and asked us where we could make the shots bigger,” Breakspear says. “But some shots were up close on her face, and we couldn’t make those more dramatic, no matter what we did.”  And, using a digital double to amp up the action was out of the question. “We need to know it’s Angelina,” Breakspear says. 

    Fortunately, the artists realized that shots in which the camera looked up as she jumped across the shaft and then down offered room for experimentation. They tried moving the CG background—the elevator shaft—quickly upward, and had a winner. “When we saw the test, we thought, ‘Wow, this is going to work,’” Breakspear says. “She really looked like she was jumping a long way down and hitting the wall hard. We ended up applying this process to 35 of the 50 shots.” 

     For those shots, the crew rotoscoped Jolie out of the filmed plates and then inserted her into a digital replica of the elevator shaft built on set. “It’s not as easy as it sounds,” Breakspear says. “When you do a complete CG environment and have to make it match something on film, it’s a big challenge. In CG, you have a million textures that look like metal and wood. But what no one seems to have done is to make a metal texture that looks like painted wood. That’s what the set construction guys do—paint wood to look like metal.” 

     When the crew tried to use a metal girder texture, for example, they discovered that the reflectance was slightly different than the painted wood on set. “It’s a crazy process, making CG look not like a real element, but like a set director’s version of a real element,” Breakspear. “We ended up taking a gray wood texture and making it slightly reflective.”

 For rendering, the CG artists used a combination of Pixar’s RenderMan, Side Effects Software’s Houdini, Mental Images’ Mental Ray, and proprietary software for point cloud data developed in conjunction with Skybucket.

Digital DC 

    CIS’s goal for the White House sequence was to convince the audience that Salt enters and then leaves the building, that a film crew shot her pulling up in a car and going to the front door, and later, boards a helicopter on the famous back lawn. 

    The director first shot Jolie entering the White House in a parking lot in Long Island, where a practical set provided the gate and the entrance. “We replaced everything with the White House and the grounds,” Breakspear says.

Placing a CG city around a digital White House helped convince audiences
that Salt (Jolie) entered and left the iconic building.

     And then, he decided to re-cut the ending and add the shots in the back. “There are only about 10 shots, but they are big shots in the movie,” Breakspear says. “The White House model was fairly dense, but what made the whole scene big was the fact that we have about 80,000 individual buildings all textured and lit so we get parallax. We had a completely CG city in the background.”

     In addition to the buildings, the crew peppered the backgrounds with traffic lights, flashing lights from emergency vehicles, trees, people, cars, and motorcycles. Massive’s software drives the vehicles, causing them to stay on the road, create traffic jams, move aside for fire trucks, and so forth. And, the people on the White House grounds are Massive agents. 

     “We were going to do a matte painting, but we said, ‘Why not do a CG background?’” Breakspear says. “When we sent temps, they were blown away by what we did. We had painted everything out and put our environment of Washington DC in, and the befores and afters are so dramatic.”

    To create the White House, the crew took pictures from a camera mounted, with permission, on the fence encircling the grounds, and then textured the CG model with those photographs “We didn’t have any bluescreens on set,” Breakspear says. “We told the director to shoot what he wanted and we’d roto [Jolie] out. We just asked them to tie her hair back. It was a brave move.”

The VFX crew replaced a stately home in the film plate with the iconic White House.
The process is illustrated here with the original film plate, the lighting, the occlusion pass,
and the final frame.

    Then, to add the environment surrounding the White House, which the audience sees as the helicopter flies over the city, the crew looked at Google Earth renditions of the area, which display the buildings as little boxes. “We found out that Google based the data on a free US government dataset,” Breakspear says. “So we applied for the dataset, loaded it in, and God help the government if they ever try to use it. The buildings are all inside out and back to front. But, it gave us rough positions.”  

    Modelers rebuilt all the objects, and artists textured the geometry with images taken of the city. “We used 3D models because we wanted parallax,” Breakspear says. “We could have textured them with anything and just used twinkly lights, but that part of Washington is modeled on Paris, and it has a specific look.”
To render the massive environments, the artists moved the hundreds of layers into The Foundry’s Nuke. “The buildings farther away rendered quickly,” Breakspear says, “but we still had to break the scene into eight scenes to render, with each part made of 60 layers.”

     Within Nuke, compositors could easily place and replace trees and other elements. “Normally, we’d have to go back into CG and tell the artists to render a tree in a particular position,” Breakspear says. “But Nuke shows you where all the objects are, and we could basically copy and paste simplified objects into the scene. We did that all the time.”

CIS Vancouver worked on close to 300 shots that stepped up the action, from
adding gunfire to re-creating Washington DC.

     Film critics gave Salt mixed reviews, praising Jolie as an action star and actor, while complaining about the story. But other than noting wire removal in postproduction, few, if any of the reviewers mention the visual effects. And that means the seasoned crews at CIS Vancouver, Framestore, and the other facilities, played their roles very well, too.

All images ©2010 CTMG, Inc. Courtesy CIS Vancouver.

Barbara Robertson is an award-winning writer and a contributing editor for Computer Graphics World. She can be reached at .