Eclectia: Star Wars

In Episode I: The Phantom Menace, more than 800 shots feature digital characters with speaking roles, to help tell the story of a time long ago, and a galaxy far, far away

By Barbara Robertson

It's huge. For Star Wars Episode I: The Phantom Menace, George Lucas, writer, director, and producer (with Rick McCallum), transported a universe from his imagination onto film, with a richness of visual detail not seen before in a science fiction film. By integrating techniques often relegated to post production right into the heart of the movie, the people at Lucasfilm and at Lucas Digital's effects division, Industrial Light & Magic, have handcrafted a film unlike any other.

Jar Jar Binks and his guards (all members of the Gungan race) are three of the movie's 66 digital characters.

Ninety-five percent of this movie is digital. Actors mingle with digital characters, puppets, and people wearing "rubber heads;" and they all move through landscapes and cities on three planets, Tatooine, Coruscant, and Naboo, which have been assembled from bits and pieces of live-action footage, miniature sets, digital models, and matte paintings. Machines are sometimes physical models, sometimes digital models, sometimes background paintings. Water, dust, fire, and smoke might be real elements in a digital environment, or digital elements in a miniature set. At ILM, the artists, technical directors (TDs), and animators used every computer graphics technique in the shop, and when those weren't enough, they invented new ones. "This is the digital back lot George [Lucas] talked about," says Barry Armour, a CG supervisor.

In this prequel to the legendary Star Wars trilogy, we meet Anakin Skywalker (actor Jake Lloyd), the young son of a slave, who will become the dreaded Darth Vader in later episodes. Anakin lives on Tatooine, a desert-like planet filled with gamblers and outlaws, where wealthy slave-owning gangsters make money in the black market. All this is illegal in the Galactic Republic, but the criminals in this recently colonized, outer-rim territory find little opposition.

The center of the Galactic Republic is Coruscant, a planet covered almost entirely with skyscrapers and spaceports. It's the seat of galactic government, the power center. Coruscant's capital, Imperial City, is home to the Jedi Temple where the Jedi Council ponders the fluctuations of the Force, tests recruits, and monitors its far-traveling Jedi Knights. As the movie begins, two of these guardians of peace and justice-Obi-Wan Kenobi (Ewan McGregor), a determined young Jedi Knight, and Qui-Gon Jinn (Liam Neeson), his venerable Jedi master-have traveled to a spaceport orbiting Naboo to negotiate an agreement with the Trade Federation, which is threatening to blockade and invade the planet.

Dozens of Digital Characters
The garden-planet Naboo is made of rocks thousands of miles in diameter, surrounded by caves. Swampy lakes, open sea, and land masses rich with vegetation cover the surface. Naboo has two separate, highly advanced cultures. Most Naboo people live in the beautiful capital city of Theed and are governed by the young, elected Queen Amidala, played by actress Natalie Portman. (In later episodes, she marries Anakin and they have twin children, Luke and Leia Skywalker.) The Gungans, an amphibious race who live in domed, underwater cities on Naboo, are ruled by Boss Nass. This entire race was created at ILM with computer graphics tools, as were several Naboo animals.

When Qui-Gon's and Obi-Wan's negotiations in the orbiting spaceport fail, they go to Naboo to warn Queen Amidala. Their landing sets off a stampede of CG animals. In the longest shot in the stampede, 61 of these strange-looking animals (from six different species) emerge from a swamp running wild-eyed and scared. Each creature has skin that jiggles as the animal runs or stamps its feet, and each has facial expressions. "Their lips move up and down with their heads," explains Marjolaine Tremblay, lead animator. "The stampede is only a couple of shots, but it's important because it happens when Qui-Gon and Jar Jar first meet." They meet by literally running into each other. Jar Jar Binks, like all Gungans, is a loose-limbed, computer-generated character that looks a little like a lizard but has the mouth of a duck, eyes on top of his head, and ears than hang down to his waist. With actor Ahmed Best providing his voice, Jar Jar henceforth travels through the movie alongside Qui-Gon and Obi-Wan, providing comic relief as their well-meaning but clumsy sidekick whose mistakes often turn out to be helpful. "He's a little bit confused, but he tries to keep up," says Rob Coleman, animation director.

Surrounded by digital characters, Qui-Gon Jinn (Liam Neeson) banters with Watto, who has lifted himself high enough off the ground to meet the Jedi Knight face to face. Watto's wings are a blur as they work hard to hold him up. To Qui-Gon's left is Jar Jar. To Watto's right is Sebulba, who uses his feet as hands and walks on his forearms.

Jar Jar is one of many computer-generated characters in Episode I. "Most of the nonhuman characters are CG," says Coleman. "They're right in the fabric of the film. The camera doesn't even always focus on them; sometimes they're in the background." There are 66 CG characters and creatures in the film (plus 33 variations of them). Ten talk, and six have full lip sync, according to Coleman. The talking characters appear in 812 of the film's approximately 1900 shots.

In addition to Jar Jar, Coleman singles out three other main CG characters: Sebulba, a pod racer on Tatooine; Watto, a junk dealer on Tatooine; and Boss Nass, the king of the Gungans on Naboo. Actor Ray Griffiths provides Sebulba's voice, Andy Secomb provides Watto's, and Brian Blessed speaks for Boss Nass. The total number of shots for these characters ranges from 40 to 80, a number that, when compared to Jar Jar, causes Coleman to classify them as having "cameo" roles. As the self-imposed sidekick for Obi-Wan and Qui-Gon, Jar Jar stars in 350 shots.

The animation for all four characters was accomplished with several techniques. Each human-type character in the movie wears clothes, sometimes several layers, which were animated using procedural animation and simulation. In addition, procedural animation, dynamics, and simulation programs were used for certain elements such as Jar Jar's long ears and the phone cord hanging from Watto's waist. "The simulation gives the characters extra realism," Coleman says. "This isn't an all CG environment. Our CG characters are in the real world dealing with physics."

The animators, however, used keyframe animation to act out each character's performance, and shape blending to create facial expressions and lip sync. For performance animation, they relied on Avid's Softimage 3D; for facial animation, they used ILM's own Caricature software. All of these programs run on SGI workstations. "These fully digital characters have to hold their own in scenes with actors like Liam Neeson and Ewan McGregor and be as believable without calling attention to themselves. That requires a subtlety of performance," Coleman says

To organize the work, Coleman divided the animation crew, which fluctuated between 30 and 45, into teams. Fifteen animators worked on Jar Jar, two to three on Sebulba, four to five on Boss Nass, seven on Watto, and between five and 10 on the droids. There are nine CG droids (robots) in Episode I, with 12 variations; they appear in 250 shots. The droids are animated with a combination of keyframe animation for the "hero" droids and motion capture for the rest.

CG Stars
To help animate Jar Jar, the team could refer to video footage on location of Ahmed Best, who provided Jar Jar's voice. "We'd block out the performance with Ahmed in the shot, and then we'd get a clean plate," Coleman says. "It saved weeks and weeks of production time." The animators also followed directions from Lucas. "George described Jar Jar as not having any bones," Coleman says. Senior animator Kim Thompson adds, "George would say, 'Dare to be dopey.'"

For this exterior shot of Theed, capital of Naboo, ILM artists combined a miniature set with digital elements; for the waterfalls, they used salt. Interior shots are the opposite: digital with some practical elements.

To animate Jar Jar's long, floppy ears, the R&D group developed an algorithm that would move them automatically, thus relieving the animators of the task. In one scene, for example, when Jar Jar spins his head around, his ears wrap around his neck. "There are so many shots," Thompson says, "if we can get away with not animating something like that, we have more time to concentrate on the performance." Similarly, for the innermost layers of Jar Jar's costume, CG supervisor Doug Smythe wrote a program that automatically generates displacement maps to create wrinkles as Jar Jar moves. A cloth-simulation program created in the R&D department moves his outer layers of clothes.

The cloth simulation was also used for Gungan leader Boss Nass's costume, a long, flowing robe. To create a performance for the jolly king, the team borrowed actor Brian Blessed's mannerisms. "The way he wiggles his fingers is from Blessed," says animator Hal Hickel. Adds Coleman: "There's jowly stuff that comes straight from Brian. You're truer to the character if you can use the face that produces the sound." The spittle that flies out of Boss Nass's mouth when he shakes his head, though, is a practical, filmed effect-it was composited into the scene after the character was rendered.
Even though he looks quite different from Jar Jar, he's also Gungan, so Boss Nass's model is a Jar Jar derivative. "We started with the same mesh," says Geoff Campbell, model supervisor. Other Gungans derived from the Jar Jar model include guards, calvary, civilians, and an old soldier known as Captain Tarpals.

All told, Campbell supervised the work of 18 modelers who created more than 200 models for Episode I and, in addition, all the facial expressions and lip sync libraries for the six main talking characters. The models were created with Alias|Wavefront's Power Animator, and the shape libraries with ILM's own Caricature and I Sculpt software. All three programs run on SGI workstations. "We use shape libraries rather than trying to create actual facial anatomy, because all these characters are so different from one another," Campbell says. "We're not working with real creatures. We have to understand them sculpturally, but not technically."

One of the oddest characters is Watto, a Tatooine junk dealer who owns Anakin's mother, the slave Shmi (actress Pernilla August). We meet Watto-and Anakin-after Qui-Gon, Obi-Wan, and Jar Jar slip off Naboo in a damaged spaceship. A search for parts on Tatooine leads them to Watto. With wings like a hummingbird, a huge stomach, and an elephant-like trunk covering the front of his face, Watto presented two big challenges for the animators: making him fly and making him talk. "He looks like something that wouldn't work in the real world," says Tim Harrington, an animator who worked on both Watto and Boss Nass. To make him talk, they decided to have him use the left side of his mouth. "We had Rob [Coleman] do poses and we took Polaroids of him, and that's what the modelers used to model his mouth shapes," says Harrington. The animators used his shoulders to motivate his movement, tilting his wings accordingly. When Watto is hovering, his feet dangle beneath him.

The wings themselves were animated using cycles. CG supervisor Smythe explains that animators would create several cycles of flapping wings, then TDs would render each separately with motion blur in Pixar's RenderMan and blend them with the body. To create Watto's "five o'clock shadow," the TDs used a fur renderer with multiple shadow passes; to animate the phone cord, they used the same type of simulation as they used for the cloth. Because the simulator must begin its interpolation before the first frame of the shot, Smythe's group created scripts to help the animators generate "pre-roll" animation.

Pod Racing
The fourth main digital character, Sebulba, is a Tatooine master pod racer. Pods are complex racing machines-two engines and a cockpit connected by ropes-that travel up to 600 mph over the desert terrain. On the ground, they're models. In the race, they're CG. Sebulba, however, is always CG. When he's not in a pod, he walks on his forearms and uses his feet like hands, which looks bizarre, but when he's in the pod, having an extra set of hands helps him do nasty things to his competitors. "He cheats a lot," says Patrick Bonneu, who helped animate him. "He tries to win at all costs." To animate his face during the pod race to create an illusion of great speed, the Sebulba animation team used Caricature to move his skin, mustache, and goggles as if they were being pushed by the wind. Many of the other pod racers are also digital, as is the two-headed announcer.

The pod race takes place in a huge stadium, which is actually a miniature set that the technical directors filled with digital people. Some of these people were captured with digital video, then cloned and turned into 150,000 sprites to occupy the stands; however, the 4000 to 5000 digital people milling around in front of the stands were modeled and then animated procedurally using a proprietary plug-in written by Hiromi Ono that runs inside Alias|Wavefront's Maya. "These digital people have freedom of will," says Habib Zargarpour, CG supervisor. "They avoid each other, they move in different directions; they can even decide to run to the bathroom."

To create the pod-race environment, the technical directors used digital matte paintings, CG models, and numerous texture maps. "We had a library of rocks, crags, and buttes," says Kevin Rafferty, lead CG supervisor. "To place textures on them quickly, we created a program that manages texture assignment." For the terrain, the R&D department created a program that would generate an adaptive optimized terrain on the fly for the miles needed during the 600 mph race. The task of compositing all these pieces was supervised by Tim Alexander, who worked with special software that compensated for the idiosyncrasies of the wide-angle lens used in the live-action shots. For example, he noticed that on the live-action plates, the color at the edges around people and objects split the red and blue, so he added that aberration to the CG characters. All the CG elements were rendered in sharp focus; the compositors added film grain, rack focus, and depth of field.

ILM devoted between eight and ten 32-processor Origin 2000s, each with between eight and 12gb of memory; two 16-processor, R10K Power Challenge machines; and four 256-mhz Challenges from its large render farm to this movie; all the machines are from SGI. "And then everybody's O2 turns into a render farm at night," Rafferty says. That effectively added another 200 machines, the SGI O2s used by the artists, TDs, and animators working on Episode I, to the render farm.

Work on the movie was divided among three visual-effects units. Rafferty had the task of overseeing all the CG supervisors on these units. "I helped make sure the foundation was sound, that the R&D came together, and that the new software and scripts being written on each unit were put into the pipeline," he says. At the peak of production, he was working with 78 technical directors, 25 compositors, and six associate technical directors. The latter were a kind of "hit team" that would help out wherever needed.

The visual effects supervisor for the cut-throat pod race sequences on Tatooine was John Knoll; Scott Squires' unit worked on sequences set in Coruscant. Dennis Muren's unit created the two big Naboo sequences: The underwater scenes-during which Qui-Gon, Obi-Wan, and Jar Jar travel to the Gungan cities-and the huge ground battle between the Gungans and the droids at the end of the movie. In addition to the pod race, Knoll supervised the so-called Rebel unit, a close-knit team that used tools such as Power Animator on SGI machines, and auto·des•sys' FormZ, Play's Electric Image, Puffin Design's Commotion, and Adobe Systems' Photoshop and After Effects running on Macintoshes, to create and animate the space-battle scenes. "Our group works outside the pipeline," says Stu Mashwitz, space-battle sequence supervisor. "We like to have one person do the modeling, lighting, and compositing for an entire shot. It wouldn't work for character animation, but it works for spaceships."

When a Jedi Knight's lightsaber slices through a droid, the droid's parts crash to the ground and bounce according to the laws of physics, as encoded into a dynamics program written specifically for droid fight scenes.

The Battles

The space battle is waged by Naboo Starfighters, yellow, hot-rod like ships, that attack the Federation battleship, a fortress in orbit above Naboo. The battleship is a motion-control miniature; the Naboo Starfighters were created by Mashwitz and his team, whose aesthetic challenge was to make the battle look like a Star Wars battle. "No one has seen a space battle, but everyone knows what it's supposed to look like," Mashwitz says. "It's supposed to look like Star Wars." So rather than put lights at infinity, they set lights as if they were working on a motion-control stage (as in the first Star Wars movies). Similarly, rather than build 3D lasers, they created them in AfterEffects. For the big battles, they put background images on sprite cards. "One big card could hold a whole pre-rendered battle," he says. "Sometimes they're 2D, sometimes 3D. We'd do what worked for the shot." Interestingly, rather than follow a typical procedure for CG animation in which the look is created with the renderer, this group likes to create and control the look in AfterEffects by mixing several render passes. "We don't do anything straight out of a 3D program. Nothing. Even something as simple as a space ship flying by takes two or three composites," Mashwitz says.

While the Naboo Starfighters wage war with the Federation battleship in orbit above Naboo, on the ground, a huge battle is being waged between thousands of Gungan soldiers and Federation battle droids. Hero animation for this big scene was done by keyframe animators. Animation for the hundreds of Gungan soldiers and droids, however, was achieved with the help of motion capture. In its motion-capture studio, ILM has installed a 20-camera, Vicon8 system. Jeff Light, motion control supervisor, put on the optical dots and became a Gungan soldier. James Tooley, a technical animation supervisor, became a battle droid. Their motion was captured using Vicon software, and that data was fed into ILM's own MOJO motion-editing software, where it was converted to a form animators could easily use.

Although most of the Gungan soldiers in the front row (holding the power shields) were animated by hand, those behind were choreographed with the help of motion-capture data and motion cycles.

"By the time an animator sees the motion data, it looks as if it were handed to them by another animator," says Light. The captured motions were polished, stored as cycles, and used to animate thousands of characters. The choreography was created in Maya, according to Christophe Hery, CG supervisor, who organized the library of 143 motion cycles by creature types. To speed the rendering, Hery developed a system that cut the time from 13 minutes per frame to 3 seconds.

Light and Tooley also helped out in other areas. Light put on a motion-capture suit and acted out the entire movie to create quick animatics; Tooley set up the animation controls for all the creatures. "Some of the most complex animation controls were on the destroyer droids, because these droids compress into a wheel and accurately roll," he says.
In this movie, it seems the deeper you investigate, the more detail you can find, not only visual details, but in techniques for creating complex scenes more efficiently. Or, more to the point: "More, better, faster," says Rafferty, who describes a scene that illustrates this complexity. "There's an exterior establishing shot of Naboo," he says, "that was created with matte paintings, augmented with CG and practical elements. There are little CG people in it, some motion captured, some practical. Everybody gasps when they see it. It takes your breath away."

Barbara Robertson is West Coast senior editor for Computer Graphics World.

Next month, in Part II of our Star Wars coverage, we look at how the effects crew created the models for animators and for sets, and at the animation techniques emerging from ILM's new motion-capture studio.

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This article was taken from a magazine's web site and as soon as I find out what site I took it from I let you know, until then enjoy this fascinating article. Star Wars: Using Digital Tools to Handcraft a Fantastic World

This article was taken from a magazine's web site and as soon as I find out what site I took it from I let you know, until then enjoy this fascinating article.

Star Wars:
Using Digital Tools to Handcraft a Fantastic World