Set largely in a meticulous recreation of 1970s San Francisco, David Fincher's taut thriller Zodiac captures the devastating impact a cunning serial killer has on the public and especially on the journalists and policemen who hunted him. To help create this relentlessly tense film, Fincher relied on two visual effects supervisors he had worked with in the past. Eric Barba of Digital Domain began helping Fincher with commercial projects in 2002. Matte World Digital's founder Craig Barron knew him in 1981, when Fincher was a camera assistant in the matte department at Industrial Light & Magic, where they worked on Indiana Jones and the Temple of Doom.

Flash presentation: Matte World's work on the film, including videos and before-and-after slides.

Digital Domain created the effects for the crime scenes plus a sequence on a two-lane highway in the middle of nowhere. Matte World Digital handled the establishing shots, sent San Francisco back in time, and gave Fincher digital camera moves that would otherwise have been impossible to shoot. There are no helicopter shots in this film, even though it appears to have several. Most of the effects are invisible.

A History of Violence

All the crimes take place in the beginning of the film, as do most of the effects. The first murder the audience witnesses happens on July 4, 1969, at the Blue Rock Springs Golf Course parking lot near Vallejo, a town north of San Francisco. We fly over Vallejo in an establishing shot and see fireworks in the distance. The shot is completely digital.

"I photomapped the environment from a helicopter at dusk and made a crude animatic based on those photographs," says Barron. "Once David [Fincher] approved the basic look of the shot, we created a more dimensional environment. Because the film takes place in the Bay Area where we're located, it was easy to shoot reference photos and digital stills that the CG artists used as texture maps. We added a blue gradation tone to give the sky a nighttime value."

Tension quickly builds; we look out from inside a car moving slowing down a dark street. You can still see fireworks in the background. Matte World added the digital fireworks to the live action plate. "Originally, they shot it with the camera inside a car," says Glen Cotter, CG lead. "But it was too shaky. So, they mounted a car door to the front of a camera, dollied it down the street and then gave us a replacement plate. David Fincher wanted that perfectly unnatural smooth move. It gave the shot an eerie look."

When the young couple stop in the Blue Rock parking lot, a man comes up to the window and shoots them. Digital Domain added CG bullet hits, CG bone fragments, and blood using Maya particles for atomized blood and proprietary fluid simulation technology for seeping blood.

"David [Fincher] wanted the entire film to be as authentic as possible and he had done exhaustive research," says Barba. "We had crime scene photos. He had interviewed the detectives. We knew how [the victims] were shot and which wound killed them."

Fincher didn't use any squibs (liquid-filled balloons) or practical blood. "Squibs and practical blood have a particular style," says Barba. "The way we went about our work is much more striking and hard hitting in its realness and rawness. That's what David wanted in terms of authenticity."

For this shot, compositing supervisor Janelle Crowshaw worked in Nuke with elements that CG supervisor Karl Denham's team generated. The team used Inferno and Nuke for tracking.

Inferno was the primary compositing tool, however, for the second murder. This time, the killer binds and then repeatedly stabs two people on a small hill overlooking a lake north of San Francisco in late September.

"The woman was stabbed to death," Barba says. "We tracked where the knife went into the woman's dress in Inferno, created the entry wounds, and added CG blood and blood seepage. When you're working on fiction, you're disconnected. But when you're trying to recreate the murder of someone who actually did die, it gets to you. It's not the kind of subject matter that makes you want to go out and get the crew jacket."

Some of the most compelling visual effects surround the third murder, of cab driver Paul Stine, which takes place in San Francisco in early October. Leading into this sequence, Matte World Digital created an establishing shot of the San Francisco waterfront. The camera looks down on the water, tilts up, and flies in toward the city with the Ferry Building front and center as Fincher might have filmed it from a helicopter.

That 1969 waterfront differed greatly from today's post-earthquake San Francisco. New buildings have been constructed, the ferry building was restored, and most noticeably, an elevated freeway that once circled the waterfront is now gone. CG artist Luis Hernandez at Matte World used aerial photographs, archival photographs, and interviews with engineers from the port authority to construct the buildings and the freeway for the historically accurate shot. The studio used 3ds Max, Digital Fusion, Shake, SynthEyes, Photoshop, and ImageModeler. Tweak Films created the water.

"In the reviews I've read, no one mentions the matte shots," says Chris Evans, chief matte artist at Matte World, "although one reviewer said that the filmmakers got the waterfront right with the freeway. Little do they know. We researched and rebuilt every building [for that shot], scaled the freeway, and modeled individual cars and trucks with windshields that reflected light in the right way. The work went on for weeks, just to get that historical accuracy."

The studio also applied its reverse time machine to the streets of San Francisco. For example, in a night shot in downtown San Francisco that leads to the third murder, the camera cranes down as a man leaves the Curran Theater and hails a taxi. In the original plate, that camera move revealed a big Starbucks sign. Matte World's artists changed it to read "Barbara's Parlor."

"We had to keep the sign because it was a light source," says Barron. "It was reflecting everywhere." Also, because the camera aimed down Geary Street, past Union Square, toward the bay, the artists removed awnings from buildings (no awnings in 1969), replaced a billboard with one advertising the play Hair, enhanced the hazy atmosphere, and extended the viewpoint of the camera.

"We redesigned everything from about a block away and replaced it," says Cotter. "It's hard for a camera to get a good exposure at night for long distances. We tried to not be out of time, but the buildings weren't a focal point, so it was more a matter of getting the shot to look good."

When the man enters the taxi, the camera moves behind to follow the yellow cab as it drives west on Geary and turns onto Van Ness. The passenger inside is the Zodiac killer.

From the point when the Zodiac gets into the taxi until he kills the driver at the corner of Washington and Cherry in Presidio Heights, the sequence is entirely CG. Digital Domain modeled the cab and loaned it to Matte World. Matte World created the CG environments.

"David [Fincher] wanted it to look like it had been photographed from a helicopter," Barron says. "But, as the taxi goes around the corner, the framing keeps the taxi perfectly in the center. That couldn't have been done as precisely from a helicopter. Creating the shot in CG was a way to make the framing precise and because the camera move was a little unrealistic, it added tension. The important thing was that the environment look absolutely real, that it didn't telegraph the effect. The shot communicated subconsciously that something was wrong because the movement was somewhat unreal but the environment was real."

Evans used Google Earth to plot the taxi driver's route and decide where to place the cameras. "I could figure out, given the elevation of the camera, how many blocks we could see," he says. "If we were at 150 feet, I could tell how much of a rooftop we would see; I knew how many car lengths would we see from top to bottom. So, we could construct the shot very accurately." The result is a camera position that would have been too low for a helicopter and too high for a crane.

Hernandez used a combination of AutoCAD, 3ds Max, and ImageModeler to plot the CG environment, model the buildings, and texture them. "It was a photogrammetry exercise," he says. "I went from building to building, rooftop to rooftop, taking photographs of Geary Street and Van Ness Avenue from street level and from rooftops."

To capture the intersection of Geary and Van Ness, Hernandez rented the top floor suite of the Cathedral Hill Hotel, waited until traffic died down at 4:30 in the morning, and then shot bracketed stills with a Nikon D2X using 15, 20, and 30-second exposures. Once Hernandez had collected the photos, he laid them on an accurate street grid that he had drawn in AutoCAD.

"I found out as I started laying out this CAD plan, that it was all about resolving the basic scale," he says. He added the photographs to create a ground plane, and then created the buildings in photogrammetry. "The buildings created in photogrammetry gave us the basic framework," he says. "Even if the building was slightly off-scale, we could position it on the CAD drawing as a template." Photographs projected onto the geometry provided detailed textures.

Once Hernandez finished building the digital set, the animation team added the yellow cab and other cars. To accent the turn at the intersection and give the street dimension, Barron had the matte artists add a grid of trolley bus cables. In addition, he shot Matte World employees looking at the taxi, crossing the streets, walking their dogs, and so forth, with Fincher's Viper camera, and composited those elements into the shot.

"I think that working natively in a digital format makes it much easier for us," Barron says. "Because the whole film was shot in a digital format, we could take shots, manipulate them, add elements, and composite then without having to worry about scanning. In fact, we did plate shoots with the Viper camera for some shots during the day and worked on them that evening. It was almost as easy to bring in live digital movies and manipulate them as it is bringing digital stills into Photoshop."

Once the cab reached the killer's destination, Digital Domain took over. For the rest of the shot, the cab is real, but the neighborhood, for the most part, is not.

"The neighborhood has changed from when the original murder took place," Barba says. "David shot in San Francisco for some of the sequence, but most of the sequence was shot at Downey Studios in Downey, Calif. There, Fincher recreated Washington and Cherry streets, built the faà§ade for two houses, and brought in period vehicles. "We added everything else," Barba says. "The rest of the neighborhood, a CG police car and motorcycle, a fire truck, and reflections on the real cars. It was an elaborate amount of work."

Fincher picked out photographs of houses that Denham's modeling crew built at Digital Domain using 3ds max. Wei Zheng, the matte painting supervisor, created matte paintings from the photos, projected them onto the models of the houses, and rendered them with V-Ray through 3ds Max. Crowshaw's compositing team assembled the neighborhood in Nuke.

When the cab stops, the Zodiac killer shoots the driver in the head. When Paul Stine was shot in 1969, the shock wave from the blast forced a ripple in his face that Digital Domain had to match in addition to creating the wound. To do that, they scanned the actor's head to build a 3D model, tracked the image in the 3D plate to match the movement, then added the effect. "We tried to match our effect as closely to the crime scene photos as possible," says Barba. "We created a cavity in the head so that our CG blood would flow and stream correctly from the brain and used projection from the plates as well as images from the actor for textures."

The shot ends with the camera pulling back from the cab. The cab is real. The neighborhood, still, is not. "I think that 99 percent of the viewers won't know what we've done," says Barba. "The effects are there for narrative. They have to be seamless."

Digital Domain also created a CG environment for a scene in which a screaming woman is illuminated by the headlights of an oncoming truck. "David wasn't happy with the original performance on a deserted road," says Barba, "but rather than reshoot it on the road, he brought in the actress and a semi truck, shot it on bluescreen, and then said, ‘I want you to recreate it in CG.'"

So, Digital Domain took the performances, recreated the road, recreated the truck using projections from the real truck, recreated the original environment, and composited it all into a final shot. "I try to stay one step ahead, but with David, it's damn near impossible," Barba says. "He keeps me on my toes."

In addition to the establishing shots in Vallejo and San Francisco, and others for Sacramento and the Ontario, California airport, Matte World created a beautiful matte painting looking down from the top of the Golden Gate Bridge, tweaked various buildings to age them, replaced cars, and changed the marquee for the North Point Theater. The most dramatic sense of changing time, though, was a time-lapse sequence showing the building of the Transamerica Pyramid to show time passing.

Steven Messing was lead artist on the shot. "We sent all our employees out with digital cameras to shoot time-lapse clouds that Ken [Rogerson] edited together for backgrounds. They are the only real things in the shot," says Barron. Hernandez researched the building to make sure the construction techniques were accurate; Cotter modeled the building; Messing painted the shot.

"We found a series of photos taken from one angle of the Transamerica building under construction," says Rogerson. The photos had been taken from the roof of a building now owned by Francis Ford Coppola, and he gave the crew permission to shoot reference photos from the same location. "Everything in the final shot is CG from that location. It's a view that you can't get today because modern buildings are in the way."

In the final shot, the building is a hybrid of 2D and 3D. "We modeled the environment to get the lighting interactions," Cotter says. "Because it's a time lapse, the lighting changes in every frame, so instead of making matte paintings for every frame, we did a lighting pass. But there isn't any parallax in the scene, so the shot is really a 2D matte painting." A matte painting that is historically accurate.

"Our marching orders from David were to make the film as accurate as possible," Barron says. "He grew up in the Bay Area, so he felt an obligation to make it realistic."

Barron likens the work on Zodiac to an archaeological dig. "The whole film is about uncovering, finding clues, and being accurate to reveal the story," he says. "The visual effects needed to follow that narrative, and that was exciting for us. It's the type of film we love to work on."