Reflections on a scene: effects artists use digital techniques to generate a period look. (Digital Video).(Road to Perdition motion picture uses Cinesite services, Cineon image-processing software)

TIMING WAS EVERYTHING when it came to creating the effects for Road to Perdition, a feature film set in Depression-era Chicago. The story line focuses on a hit man whose wife and youngest son are killed when his private and personal lives collide, and details his subsequent journey of revenge, which he takes with his surviving son in tow. In the live-action drama from DreamWorks/Fox, set designers re-created this stormy time period in the Windy City's past. However, for one particular sequence, Cinesite, an effects studio based in Los Angeles, transported viewers using digital imagery that was precisely tracked and integrated into the scenes.

A Reflective Moment

The 45-second segment opens as the camera focuses on the hit man, played by Tom Hanks, who is seen through the windshield of his car as it approaches the city. His son, who had been sleeping in the back seat, awakes in amazement as he sees the impressive cityscape for the first time, with reflections of tall buildings playing on the windows. As the car drives away, the shot pulls back to an overhead view showing the car passing over Chicago's LaSalle Street Bridge.

To create the splendor of the sequence, Cinesite lead compositor Ted Andre seamlessly combined imagery from two separately filmed locations in Chicago to simulate the 1931 period look. The live action for the entire sequence was filmed without greenscreen at the LaSalle Street set location. For the first portion of the shot, the car was stationary, though it was rocked gently to help simulate actual forward movement. Certain windows on the car were covered with opaque white paper, which was digitally replaced with moving background footage that was filmed at the Belbow Street location and then composited into the live-action scene using Kodak's Cineon software running on SGI's Irix platform. When the shot progressed to the appropriate point, some of the paper was removed from the windows to reveal certain LaSalle Street backgrounds.

Visual effects supervisor Michael McAlister set up three cameras on a truck, in a panoramic fashion, with overlap between three different images, to capture the background footage that would later be used to create the illusion of movement in the car element. According to Andre, the background plates were anamorphic, or squeezed cinemascope, that had to be stitched together to form one continuous plate. As a result, even the smallest amount of jitter would be amplified because of the additional distortion that cinemascope lenses inherently introduce at the edges where the plates meet. To overcome this situation, Andre removed the distortion, and masked the "stitched" seams using parts of the car.

"At the edge of the frame, these plates had a tendency to slide against each other if the stabilization was the least bit off," Andre says. "So it was imperative for this step to be done with extreme accuracy, to prevent issues with the positioning of the horizon line." He used Cinesite's proprietary tracking software for most of the background stabilization, with some of the elements requiring more than 800 tracking points due to the nature of the camera move. Once the plates were stabilized, digital camera shake was added to simulate motion, making it appear as though the car were moving along the road the entire time.

Using a combination of Cineon and proprietary software, Andre gathered motion data from the foreground car element and applied it to the background images (at a percentage, to account for parallax) so that when they were composited, the two perspectives would match. "For the overall positioning of the horizon line, I ended up having to do a lot of hand tracking. Procedural methods work up to a point, but then it becomes an artistic call," explains Andre.