"The severed body didn't fall to the floor with exactly the right trajectory, plus the director really wanted the actor's eyes open during the decapitation," recalls Jon Campfens of a scene in Saw V, fifth in the gloriously grisly horror series from Lion's Gate Films that opened to blockbuster business last week. Campfens' company, Switch VFX in Toronto has supervised visual effects on the last three Saw features.

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"The severed head didn't fall to the floor with exactly the right trajectory," says Saw V visual effects supervisor, Jon Campfens. Read about how Jon and his team augmented this scene and get the inside scoop on other Saw series' secrets. Clip courtesy of Lion's Gate Films and Switch VFX. (Click to play. Movie will begin playing once loaded.)

For those who haven't, well, seen Saw, the series revolves around the Jigsaw Killer who kidnaps a series of victims (usually pitted against each other) and places them in deadly Rube Goldbergian traps that afford them the opportunity to repent the ways in which they may have taken their wonderful lives—or the lives of loved ones—for granted, or suffer the consequences.

Saw Series Superstar: The Jigsaw Killer. Image courtesy of Lion's Gate Films.

In the first Saw, for instance, a doctor has to saw off his own foot and leave his fellow victim—chained to a rusty, old industrial wash basin—for dead in order to save his own skin. And though the series has tried to remain true to its gritty, low-budget roots (the first movie cost $1.2 million and grossed over $100 million worldwide), the visual effects have gotten more complex with each installment.

Head First

"Going into prep; we knew we had the decapitation to look forward to," jokes Jon. "Head comes off, body drops. Usually, we'd shoot that kind of thing against a green screen. But after seeing the trap, we knew there was no way to shoot the element, or actor, somewhere else, then bring back the trap in post. Everything would require rotoscoping."

Rotoscoping refers to the technique of matting, or separating, an "element"— an actor, prop or set piece—from a live-action "plate," or footage, so it can be composited, or digitally "blended," over another background later, in post-production.

The live-action plates didn't align exactly for this gruesome decapitation sequence in Saw V. Image courtesy of Lion's Gate Films and Switch VFX.

In the scene, five victims linked by a rotten real estate deal (hey, someone's gotta pay for the sub-prime mortgage mess) are tethered together via wire threaded through collars around their necks, and they're cuffed to guillotines timed to decapitate them. The "gag," as its known in Saw parlance, is that the keys to each collar lay tantalizingly out of reach in five glass cases. If the victims can work together to retrieve the keys, they'll escape. If not, at least one will go all Marie Antoinette on the audience.

Severed head image
Talk about a severance package! Image courtesy of Lion's Gate Films and Switch VFX.

"We shot a live-action plate of the actor yanked back into a cage without the guillotine," Jon explains, "and then shot the plate again with a sock around the actor's head to contain her hair and simulate the severed body falling forward." When the team got into post, though, there were problems with the plates, which didn't align properly. "We had to fix the alignment in post, and resize her body so that all the elements fit together," says Jon.

"The actor's eyes were closed during the part of the scene that was supposed to simulate the decapitation and the director wanted them open," recounts Campfens, "so we added open eyes from a different plate, which made the shot much more horrific. We had to create a computer-generated head, a CG 'dog collar,' and lots of digital blood." Now, a CG head typically requires a full, 360-degree laser scan of the actor, but, since the budget didn't allow for a fully-scanned digital double, Jon created his "poor man's" version through a series of hi-resolution still shots (10 megapixels) of the actor rotated through the same angles.

There Will Be Blood

"Budget constraints do force us to get creative," says Jon. Since VFX is his stock in trade, it might be surprising to know that Jon also likes his "elements" as real as possible—including blood. "Well, despite what you might think, we don't engage in ritual sacrifice around here," Jon laughs, "so, when I say 'real blood,' I mean shooting that element in-camera using practical effects like liquid corn syrup dyed red, which the crew shoots seven ways to Sunday." And still, they'll need to augment it. Like every other liquid, blood is tricky to render digitally. "There's a viscosity to it," says Jon, "and a way that light plays on its surface."

Blood picture
Sweet treat: That dripping blood (liquid corn syrup dyed red) began as a practical, in-camera effect before being enhanced in post-production. Image courtesy of Lion's Gate Films and Switch VFX.

Light and reflection are particularly difficult to render on shiny, hard-surface 3D objects like the pendulum in one scene that swings down and slices its victim open with the precision of a Ginsu knife. The resulting "object" is a combination of practical and virtual (the CG pendulum was created with Maya). Jon says working on these scenes is a lot of fun. In fact, he says co-worker Gudrun Heinze, a compositor he describes as a "gentle, animal-loving vegan" gets the most perverse pleasure out of doing "virtual harm." Better that than the real thing.

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Ever feel like the walls are closing in on you? The protruding bone is entirely virtual. Clip courtesy of Lion's Gate Films and Switch VFX. (Click to play. Movie will begin playing once loaded.)

Campfens and his band of merry mayhem-makers eagerly anticipate work on Saw VI, slated for an October 2009 release. After all, like the Macy's Thanksgiving Day Parade and a visit from Santa, the Saw films have become a holiday tradition.

Rocky Horror Redux

It was on the set of Saw IV that Campfens says then-director Darren Bousman started kicking around the idea for his magnum opus horror musical (think Rocky Horror), Repo: The Genetic Opera, for which Switch VFX created some of the most complex sequences in its history, including the entire opening: a two-minute CG cityscape using Maya, crafted by 3D Lead, David Alexander.

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One of Repo: The Genetic Opera's breathtaking virtual cityscapes, created using Maya. Image courtesy of Lion's Gate Films and Switch VFX.

"We started with 2D concept art, simple CG drawings, and Photoshop® layouts for the cityscapes," recounts Campfens. The live sets, including a graveyard and opera house, were a combination of studio and green screen to create Repo's dystopian society in which disease has caused a global plague of organ failure. Enter GeneCo, a biotech Big Brother that finances transplants and repossesses those who pay late or default (making that 19.9% introductory APR look pretty good by comparison). 

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One of VFX Supervisor Jon Campfens' favorite sequences in Repo: The Genetic Opera is "the bug sequence," featuring an array of CG arachnids. Clip courtesy of Lion's Gate Films and Switch VFX. (Click to play. Movie will begin playing once loaded.)

Yes, this is the film you may have heard about that features Paris Hilton, and while she added a certain camp value, stage veteran and Phantom of the Opera muse Sarah Brightman stars, along with Paul Sorvino, Anthony Head, and Alexa Vega. "We spent a year working on the visual effects for this film and they are spectacular," says Campfens, who promises: "I guarantee, it's like nothing you've ever seen!" Repo: The Genetic Opera opens Friday, November 7th from Lion's Gate.

A Horror Hybrid

If "horror musical" sounds like an oxymoron, how about "Christian horror film"? While acknowledging that the Bible is something of a horror show, what with all the plagues and the locusts and the smiting, VFX Supervisor Mike Webber insists the moniker makes sense. "It simply means no gratuitous sex, violence, or profanity, but still very scary," an apt description of House opening November 7th from Roadside Attractions.

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A maniac is out to get this terrified couple in the Christian horror film, House. Image courtesy of Roadside Attractions.

Webber first teamed up with producers Ralph Winter (X-Men, Fantastic Four) and Joe Goodman, who pioneered the hybrid genre, for The Visitation, a Christian horror film (actually, Webber prefers "supernatural thriller") in which an evil presence, uh, bedevils a small town and a stranger professing to be Jesus Christ. (Jesus is played by Edward Furlong from Terminator 2.)

In one scene, Furlong writhes and screams on a downtown street as a swarm of bugs fly out of his mouth. "We started with a simple, locked-down shot of the actor to capture the native, in-camera footage," says Webber, "then augmented Furlong's face in post and created a swarm of CG bugs using Maya."

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The actor's mouth was morphed to appear wider than normal as a swarm of CG bugs fly out. Image courtesy of 20th Century Fox.

Actually, there was some discussion as to whether the bugs were actually bugs or evil particles. "I came down on the side of bugs," laughs Webber. "Like little gnats, with wings." In fact, the buzzing sound of the wings foreshadows their appearance, which Webber believes made the scene even more disturbing. "We used 2D morphing software called Combustion to make Furlong's face and mouth open wider than normal," sort of like Soundgarden's "Black Hole Sun" video, but more creepy than cartoonish. "Then we mapped his face and mouth to get a rough 3D model, and used dynamic simulation to track the direction of the swarm—which had to seem both purposeful and random, like a real swarm of bugs or bees—and composited the whole thing."

Incarnating Evil

The next film on which Webber worked with Goodman was THR3E, a thriller about a serial killer, for which Webber decided to test a small VFX house in Poland called Lightcraft. "Oh, they saved us," Webber remembers. "Because of our budget and short shooting schedule, several shots we got in-camera didn't quite work." For instance, in one scene a bus blows up. Trouble was, the bus shot in the live-action plate and the stunt bus didn't exactly match. "The stunt bus was a different color and it had stripes on the side," laughs Webber, "but Daniel Markovich and his team at Lightcraft did a great job augmenting the sequence using rotoscoping, 3D models, and computer tracking and compositing."

Because of the confidence Lightcraft inspired on THR3E, Webber was willing to use the VFX house for all the visual effects on House, and the film was shot on location in Poland, which stood in for rural Alabama. In the film, two couples find themselves in a fight for survival against a maniac intent on killing them. "In the initial script breakdown, there were over a hundred visual effects shots, which escalated to 150 once we wrapped principal photography," notes Webber. Ordinarily, effects of this magnitude are found on features with ten times the film's modest $3 million budget.

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This is one house that takes possession of its owners, and not vice versa. Image courtesy of Roadside Attractions and Lightcraft.

Webber describes one "noticeable effects scene" in House (as opposed to augmentation, which simply corrects or enhances native footage). In this scene, two couples are trapped in the house that suddenly turns to ice as water pours in underneath the door and travels upward, across the ceiling. As one character frantically pounds on the floor, it turns to ice and cracks, and she falls through. "We shot the scene on a soundstage with a Plexiglas floor, the camera underneath," says Webber. "Then, using fluid dynamics and RealFlow, added the enveloping water and, later, 'breath' to frost going up the walls and on the floor."

Actress falling through ice
The camera was positioned underneath a Plexiglas floor on a soundstage to capture this footage of the character falling through. Images courtesy of Roadside Attractions and Lightcraft.

Webber credits Lightcraft's coordinator, Mariola Niedzwiecka, with making the logistics work. "First, the 35mm native footage was flown to Los Angeles for DI (a digital intermediate file that gets imported into nonlinear editing software such as Final Cut or Avid), then we'd send these huge 10-bit files back and forth over the internet via .ftp." Add to that the language barrier (Webber speaks very little Polish) and the fact that while the visual effects team was in Poland, editing was done in Los Angeles, and disaster could have ensued, but didn't.

A smoky, fluid substance personifies evil in House. Image courtesy of Roadside Attractions and Lightcraft.

"It's funny, a language barrier even comes into play when all the creative collaborators speak English," says Webber, who describes an element in House that was open to everyone's interpretation: "Evil was foreshadowed by a smoky, fluid substance that becomes ever-present by the end of the film, oozing—or wafting—out of characters' cuts and sores with that sense of, there's really no other word for it, intention we talked about with the bugs in The Visitation." It became clear that everyone had a different idea of what evil incarnate, especially smoky, fluid evil, looks like. "I realized probably the closest thing to what we were trying to create was dry ice, so I went out with a camera and captured as much footage of dry ice as I could, which got us all on the same page." The effect took several months to create using proprietary software. "But, to see this substance, this evil spirit on screen, creeping around and emanating from open sores," says Webber, sounding like a proud parent, "well, it was a thing of beauty."