T3: Man vs. Machine

Negative space: An innovation in digital makeup, ILM created an ultra-wounded Arnold complete with CG endo-skull, a CG wound-border abutting real skin and see-through backgrounds.

Terminator 3: Rise of the Machines pits a good Arnold against a bad female Terminator from the future, T-X, who's come looking for John Connor, the human destined to become such a pest to the mighty machines of the future. To make the battle between the two mechanized stars believable, the T-X needs to be super bad. Transformer-like, she can turn her arm into a "plasma cannon" and start blasting. She can run and catch up with you, diving off a cliff if need be, and land on your car's roof. And she can make any machine she comes in contact with, including police cars or a giant construction crane, do her bidding.

"One thing that [director] Jonathan Mostow said from the beginning was, 'Nothing's magic in this!' It's all science, basically," says ILM animation director Dan Taylor. "He didn't want anything that felt other-worldly. The Terminator movies have a very visceral feel to them." So a "huge design problem" for the ILM (www.ilm.com) team was "how's all this gonna work" in a plausible, mechanical way?

FIRE AWAY

When T-X turns into a full endoskeleton her movements still belong to actress Kristaana Loken thanks to motion capture.

Taylor adds, "There was plenty of 'cheating' going on," in making the fanciful cannon appear to grow out of T-X's arm, "but the end result is that what you see is very plausible; that this thing could move and transform the way it does. There's liquid metal that has to flow over this cannon and there's certain tech requirements that people doing the liquid-metal-particle work need to have for the metal to flow correctly."

REPLICATING ARNOLD

"There's a shot where one of the T-800s turns and looks right into the camera. We knew this was going to be kind of a neat moment. That Terminator's staring at every person in the audience! We added this really subtle thing where he comes around and pushes his head forward into the camera just a little. That's where the really creepy factor comes in." (This turns out to be John Connor's recurrent nightmare.)

It's part of a very busy aerial shot with innumerable Terminator/soldiers on patrol - easily 40 in a given scene. One challenge was to provide a sense of irregular terrain to this futuristic battlefield. "Usually on a mo-cap stage, people are walking on flat ground," says Taylor. But the team did not build a ground plain in the computer to match the uneven ground plain of the motion capture stage. "Mauricio Baiocchi, one of our animators, came up with a technique that was pretty clever," Taylor says. The ILM team threw all kinds of junk onto the mo-cap stage, apple crates, sandbags, wooden ramps and such and let the mocap performers maneuver through it all. Baiocchi wrote a program that recorded where in 3D space each actor's foot came down, creating a dot-pattern "like a point cloud of what the terrain would be like and we just mapped the grid to that! We just brought the ground to where their feet were. There was a lot of that type of thinking going on on this show - I call it a 'garage mentality' that sometimes is missing in this high-tech world."

Digital doubles often fill in for real actors, especially in explosive scenes with flying debris.

DIGITAL STUNT WORK Despite the obvious relief of expensive on-set accident insurance, a real danger in exploiting digital doubles comes from signaling the audience that the actor is suddenly not real when a stunt is called for. "People know what people move like," Taylor says, "they'll know on a subconscious level when something looks fake. With digital doubles, less is more - you don't want it to draw attention to itself because it's too active; you want to think it's a stunt person." But with explosions, for instance, Mostow wanted to have flying debris blow through the robotic combatants and not have to avoid vulnerable human actors. By placing digital doubles in such shots, an explosion's full fury can be captured (and ILM is known for staging and filming some furious live action pyrotechnic shots) without having to "choreograph" the positioning of live actors.

Among the threats the T-X character faces, we see her double struck by a crashing helicopter. And Arnold takes pains to crash a Jeep into her. "We did motion capture with Kristaana," says Taylor, "she came here and was a real sport about it; we put her in this Spandex suit with all the sensors on it." Director Mostow loves the first Terminator movie, Taylor says, "but in that film's climax, with the original stop-motion rendition of Arnold's endoskeleton, Jonathan felt a disconnect. He thought it was very cool but it wasn't Arnold anymore. Motion capturing Kristaana on the ILM mocap stage allowed her to drive the base performance and maintain those qualities so important to her T-X character. The result is no disconnect when she becomes a total endoskeleton. "We then did keyframe work on top of her mocaped performance." Taylor says. Work on ILM's mocap stage helped to reserve Loken's characterization of a female Terminator with her "definite, staccato moves. You still get a sense of it when you see the endoskeleton, where you go, 'That's still Kristaana!'"

TURNING THE OTHER CHEEK

Then there's the matter of destroying Arnold's face. In an intense action sequence Arnold loses half of his face when he crashes a helicopter into the "Terminatrix" in an attempt to disable her but sustains serious damage to himself. His wounded half reveals his underlying robotic skull, chest and other areas. "We were able to cyber scan a digital duplicate of Arnold," says Taylor. "We put our animation controls in there and do what we call 'matchimation.'" Arnold wore facial makeup that created a jagged edge over a green half-mask as well as other body parts: "anyplace that he was going to be endoskeleton, he was green." ILM's Marla Newall and her team would take their arsenal of software and CG Arnold model and match it "very precisely" frame by frame to the actor's movements "so that now you have our 3D Arnold moving exactly the way the real Arnold was moving." And within the look-alike 3D Arnold lay the CG robotic skeleton which allowed the animators to blow away portions of Arnold's human exterior - and head - at will. "What it means is you have negative spaces in his head," Taylor stresses, "you couldn't do that with an appliance. Where his head is split, you'll see right through the mechanics - a hole in his head. It's the first time we've been able to do that to a Terminator."

ILM created a 3D rendered crane and many layers of debris for a sequence that imparts exaggerated impact and weight to the ultimate crash.

ILM's innovative "negative space" work on Arnold's wounded face - a kind of 3D makeup - required plenty of careful compositing. "There are some real close-up shots of his face where you can see the incredibly detailed 3D renders," says compositing supervisor Jeff Doran. "There are actually holes in that part of the skull and you can see the plate behind him that we restored. There was a lot of hand painting and tracking work. Then it's a matter of getting the match-moved, 3D rendered skeleton of the Terminator and compositing that onto Arnold's face where the green patch is; then just adding atmospheric glows and making sure that what's revealed in that negative space is tracking correctly and working with the original. There's a lot of fire and smoke behind him and a lot of set details, things like flickering wall that had to be synced up with what was happening in the actual plate." There is even a rendered layer of soft-split "blend mattes" between the live action skin and the rendered skin. Now, Doran says, "It would be difficult to tell where the render stops and the live action Arnold starts."

EXIT, PURSUED BY CRANE

Another trick ILM used in T3 Taylor calls the "reality cam," a technique used in Jurassic Park III in which attacking dinosaurs seem to make the picture itself shudder. "It's got a real rough, panicky feel to it" as if the camera operator too is involved in the onscreen struggle, Taylor says. On a psychological level, the audience is meant to feel, "Oh yeah, we're looking at something real!" T3's jittery reality-cam scenes added to Mostow's quest for a sense of visceral, mechanical reality - especially when that huge construction crane flips into the air and comes crashing down, nearly skidding into the viewer's lap.

But one tough challenge was to impart that sense of reality to a high-speed pursuit scene involving T-X at the wheel of a giant construction crane. "We did an awful lot of compositing work in that," says Doran. The sequence was tricky due to the disparate camera angles and light issues that needed to look as if they were all shot during the same action sequence. "We had the big 3D rendered crane in a lot of the shots where it's crashing and flipping over," he says, "and lots of particle renders that had to blend in - digital smoke and debris coming off the crane when it impacts. We blended that with practical elements that we shot onstage."

ILM makes sure you can tell when it's over for the Terminatrix: "Throughout the whole movie she'd been about purpose, showing no emotion. But just before her lights go out, we were able to give her endoskeleton face a sense of fear," Dan Taylor concludes, "and it's a very powerful moment."

For more on T3 and Jeff Doran's compositing work, and an interview with ILM technical animation supervisor Dennis Turner, go to www.postmagazine.com.