in-depth features about how cutting-edge CG was created for various movies
making Oscar buzz.
Once upon a time in the 1980s, so the story goes, the US was sliding down the slippery slope toward nuclear war with the Soviet Union. Enter a group of retired crime fighters and costumed superheroes who either had melted into everyday society a decade earlier after being outlawed or are working covertly for the government. The murder of a government-sponsored superhero pulls these vigilantes, the Watchmen, back into action. As they investigate the murder, some of the Watchmen discover an evil plot by one of their own that could lead to nuclear war, and they uncover a conspiracy aimed at killing them, one by one.
Originally a 12-issue graphic novel created by Alan Moore (writer), Dave Gibbons (artist), and John Higgins (colorist), and published by DC Comics in 1986 and 1987, the Watchmen have now leapt onto the big screen. Directed by Zack Snyder of 300 fame, the Warner Bros. film brings to life the superheroes Ozymandias, Rorschach, Nite Owl, the Comedian, the Mystic, Silk Spectre II, her mother Silk Spectre, and Dr. Manhattan.
Although called “superheroes,” only one has super powers: Dr. Manhattan, the former scientist Jon Osterman (actor Billy Crudup), who acquired his power when an intrinsic field subtractor accidentally zapped him. He still looks like Osterman (Crudup), but he’s bigger, buck naked, blue, and he glows. Also, he can cause people to explode.
In the film, once Osterman becomes Dr. Manhattan, he’s CG, a character created at Sony Pictures Imageworks who stars in approximately 38 minutes of the film—mostly in close-ups.
“It was ambitious, and scary,” says Peter Travers, visual effects supervisor at Imageworks. “Digital humans are so hard to do. When I read the graphic novel, I thought it was the weirdest comic I ever read. I said, ‘We have to do Dr. Manhattan, and it has to be all CG.’ DJ was on the same page.” DJ is John Des Jardin, overall visual effects supervisor.
They reached that conclusion after first painting an actor blue. “He looked like what he was: like a member of the Blue Man Group,” Travers says. “But, the director wanted to see his internal structure, and we could make him translucent. It was an opportunity for us to focus on one primary character.”
Although digital doubles, even blue doubles, are usually CG because the human actor can’t do the superhero stunts called for in a film, this superhero isn’t particularly action-oriented. “That’s what makes him creepy and scary in the movie,” Travers says. “He does a subtle gesture with his hand and explodes people. What we had to stress was the subtlety of performance. It was cool. And, challenging.”
A Thousand Lights On Set
The decision to create Dr. Manhattan in CG freed the director to cast any actor he wanted in the role; he didn’t need to pick a large, muscle-bound, supersized actor. Instead, Snyder cast 5-foot-8-inch Crudup. On set, Crudup wore a white suit designed by Chris Gilman of Global Effects that was covered with approximately 1000 blue LEDs and a handful of tracking markers. The soles of his shoes had blue LEDs baked into them so Crudup would emit light under his feet as he walked. He also wore a hat and gloves covered with LEDs. Technicians could dim and turn on and off all the lights remotely.
Tiny hairs covering Dr. Manhattan’s body catch the light and help make his impossibly blue skin seem to have possibly human origins. The glow surrounding the blue superhero is a 3D volume parented to his computer-generated body.
“The LEDs were bright, but they didn’t encumber the suit,” Travers says. “Without them, we would have been guessing in every shot how the character emitted light and how that light affected the environment. He looked like a walking discotheque, but in scenes where he makes physical contact, the lights were really important.”
That was especially true for a love scene. “He sticks his thumb in a girl’s mouth, and there’s blue light everywhere,” Travers says. “We see localized light moving across her face, pinpoints of light. It’s like they are making love in a tanning booth.”
First You Take Manhattan
To capture Crudup’s performance, Imageworks placed tracking markers amidst the LEDs attached to his suit, two-inch squares with unique black and yellow patterns for manual and procedural tracking. They also sprinkled dots on his face.
“The movie is close to three hours long, so Zack [Snyder] did a lot of quick shooting,” Travers says. “He’s notorious for being really good and really quick. We couldn’t drag in a big motion-capture set; we had to get what we needed, but stay out of the way. And, I wanted to make sure we didn’t sacrifice Billy’s performance for the sake of motion capture.”
Thus, rather than setting up motion-capture equipment, the Imageworks crew filmed Crudup’s performance with HD witness cameras and derived motion data from the digital video as well as the primary film camera.
“There was a moment on set, maybe a week or two in, when Billy was getting familiar with the suit,” Travers says. “He walked over to me after a take and said, ‘I think I was slouching. Can you take my slouch out?’ I said, ‘Of course we can.’ And he said, ‘This is great.’ That was a moment. He opened up after that.”
In addition to the performance capture during shooting, the crew put dots on Crudup’s face and captured data with six HD cameras as he performed FACS-based phonemes and emotional expressions. Modelers and riggers used this data to create and control face shapes and poses.
“The motion-capture team would analyze the video footage, tracking the dots on Billy’s face in 2D with proprietary software, run an analysis, and get back a ‘solve,’ and that drove the FACS poses,” Travers explains. “As the dots moved, they triggered a certain percentage of each pose, and that fed into the control system. The main thing the facial-tracking system gave us was a good sense of timing.”
Thus, although the system didn’t match the shape of Crudup’s expressions exactly, the timing helped an animation team led by Kenn McDonald re-create performances more quickly. “When you’re matching an individual performance, it’s the number of frames, not the number of shots, that’s important,” Travers says. “We had dialog shots that were 500 to 600 frames long.”
To reproduce Crudup’s expressions, the animators painstakingly worked on a split screen, with video footage on one side and the CG model on the other. “In my opinion, the only way to make human animation look right is to give talented animators time to do their work,” Travers says. “We tried to supply the animators with as much weaponry as we could to get it done.”
Riggers provided some of that weaponry in the form of facial controls designed for subtle touches and a stoic demeanor—a slight nostril flare, an eye twitch, crow’s feet, facial tics. “There’s a shot in the expanded DVD release in which Malin tells Dr. Manhattan she slept with another guy,” Travers says, referring to actress Malin Akerman who plays Silk Spectre II. “Doc’s head turns a little and you see a little bit of muscle flex on the back of his jaw because that’s what Billy did.”
Although Dr. Manhattan has a human form and facial features, he’s made of galactic material. Internally, he has a fibrous structure, but no bones. Gases swirl throughout his translucent body, in his chest, and in his appendages, becoming wilder when he attacks an opponent.
To achieve that look, the Imageworks crew borrowed techniques and technology from a system originally developed to art-direct the fire in Ghost Rider (see “Blazing Effects,” February 2007). For Dr. Manhattan, they created layers of dense particles in Side Effects’ Houdini that, in turn, derived a volume. Imageworks’ proprietary volume renderer, SVEA, rendered the flowing particles.
Actor Billy Crudup wore a suit fastened with a thousand blue LEDs to cast Dr. Manhattan’s blue glow on his fellow actors. Animators at Sony Pictures Imageworks began with data captured from Crudup and applied his performance to the CG character.
The crew also spent time creating detailed skin textures by starting with photographs of Crudup, and then tinting the painted textures blue. “He looks like a blue man, but not a painted blue man,” Travers says. “I’ve learned that when you do texture capture, you have lighting built in. When you add lighting after you apply the texture to the model, you’ve double lit it. So we cranked the contrast in the texture, the bump, the sheen, everything, and the detail looked right. You could read the texture.”
To keep the CG character’s skin from looking too smooth, they covered his body with peach fuzz, little hairs that caught the light. On his face, they added eyebrows, lashes, and tear ducts. And, as is common now, the lighting artists used subsurface scattering to make the skin look fleshy, but they reversed the typical use of ambient occlusion. Usually, ambient occlusion creates soft shadows in areas light can’t reach—like a character’s armpits. But because the skin of this character emits light, his armpits were doubly lit.
Am I Blue?
In addition to Dr. Manhattan’s well-lit internal structure, the character also has an external glow. Rather than cheating the glow using a 2D system, the crew built a 3D volume that surrounded the CG character as he walked around.
“We parented the glow to his body,” Travers says. “We could dial in how much glow he had. If he put his hand on his chest, we doubled it up.”
The color of the glow ranged from cyan close to the character’s body, to indigo farther away. Similarly, Dr. Manhattan’s skin is indigo, but his internal structure, that is, his internal light source, is cyan. The color matched how the LEDs on Crudup’s suit responded to light. “We tried to match the real lighting in spirit with our fake lighting,” Travers says.
Most of the time, the superhero is bright, and the lighting artists could take lighting direction from the environment. “When we looked at the plates, they weren’t quite good to go because we had to remove Billy, but the lighting was incredibly effective,” Travers says. “We got all that emitted light and the reflections for free.”
When the lighting artists needed to simulate the lighting in the environment, when a scene called for the character to light himself, and when he was in a CG environment, they would cover the CG character with 10,000 point lights.
His eyes are also a light source. They don’t have irises or pupils; they’re white with a soft gradation from a pupil area to the edges, to make eye movement noticeable. When he blinks or closes his eyes, the lights turn off. The effect of the white eyes against a blue face that closely resembles Billy Crudup on a glowing blue body filled with swirling gases is dramatic. Dr. Manhattan may be one of the weirdest members of the digital human family tree, but he’s successful.
“We were sitting in the truck one day watching dailies, and Zack [Snyder, the director] pipes up with, ‘What the hell are we watching? This is the strangest thing.’ But, he always says that if it’s really strange-looking, then it’s right.”
Barbara Robertson is an award-winning writer and a contributing editor for Computer Graphics World. She can be reached at BarbaraRR@comcast.net.