Believability is the hallmark of the vfx in the third Mission: Impossible movie. All images ™ & © 2006 Paramount Pictures. All rights reserved.

The first one was a stylized spy movie; the second one was pure action extravaganza. For the third Mission: Impossible movie (released by Paramount on May 5), producer Tom Cruise and director J.J. Abrams set out to firmly ground the story in reality. This time around, you won’t find a helicopter chasing a bullet train in a tunnel, or any acrobatics on motorbikes. In M:i:III, the action scenes needed to look absolutely believable.

Vfx supervisor Roger Guyett of ILM and his team invisibly enhanced the action in some 550 shots.

For lead visual effects vendor Industrial Light & Magic (ILM), this meant invisibly enhancing the action in some 550 shots. This was especially true for the nighttime sequence in which agent Ethan Hunt (Tom Cruise) jumps off the rooftop of a skyscraper in Shanghai, China. “Shooting the stunt on location presented major problems in terms of visibility, mainly because of haze and pollution,” recalls visual effects supervisor Roger Guyett, who oversaw the project with visual effects producer Shari Hanson. “So, we decided to recreate Shanghai in the computer in order to produce as spectacular a backdrop as possible for the sequence. Tom Cruise really jumped off a building, but it was a set piece built on top of the façade of a parking structure at Universal Studios. The entire Shanghai environment was digitally added later on.”

Building a CG Shanghai
To start with, associate visual effects supervisor Russell Earl and a small crew spent four weeks in Shanghai photographing all the downtown buildings in high- resolution. The high dynamic range images were photographed at night with long bracketed exposures, as to capture the trademark neon lights and signs of the Chinese city. For each shooting session, the Canon digital camera was placed on a “tilemaker,” a programmable computer-controlled head that moved around a few degrees after each shot. Still after still, the camera captured the entire environment of each location at 360°, building up a spherical representation of Shanghai from each particular point of view. “Since we were shooting with long exposures, the lighting conditions had changed quite a lot by the time we got to shoot the last image of a series,” Guyett adds. “When you looked at the stills, you could actually see the level of haze — or pollution — changing the dynamics of how far you could see in the city. The visibility basically changed from one day to the next, and some time, from one hour to the next! So, we had a lot of grading to do before we could actually tile those images together.”

A CG Shanghai was created for M:i:III based on hi-res images the vfx crew shot in China. Above, director J.J. Abrams sets up a shot that takes place in Shanghai. Photo Credit: Jasin Boland.

The tiled photographs were complemented with hundreds of additional stills of the “hero” buildings at closer range. The last step consisted of shooting high definition footage of all the main locations, as to capture the moving elements of the city. Since traffic was very limited in Shanghai’s office district at night, the ILM crew filmed busy streets in other areas of the city and later dropped those images into the main plates, creating the requested lively backdrop.

Back in California, the Canon raw images were converted to 32-bit EXR files, ILM’s new open format. Using in-house photogrammetry tools, the CG department led by Gerald Gutschmidt and Patrick Tubach took those images and managed to recreate the basic 3D geometry of each hero building. Architectural features were then added by projecting the Shanghai images onto the corresponding 3D models, a task that was accomplished in ILM’s proprietary Zeno: a hub that handles file conversion for multiple applications. The result was a three-dimensional high-resolution matte painting in which the camera could move around.

“Using Maya and RenderMan, we first did a rough layout of the city, deciding what we were going to keep, what we were going to delete, and where the hero structures would be located,” Guyett notes. “Based on that layout, we put more efforts into the modeling of the buildings that were going to be closer to camera, as to obtain different levels of parallax whenever the camera moved. One of the advantages of creating the sequence in the computer was that we could re-organize the city, so that every angle revealed a spectacular backdrop of Shanghai. Using matte painted elements, we also often modified existing buildings to add a sense of danger to the scene.” The various layers were mostly combined in Shake, but lead compositors Mike Conte, Robert Hoffmeister, Sean Mackenzie and Todd Vaziri also used ILM’s proprietary CompTime.