Issue: Volume: 26 Issue: 2 (Feb 2003)

Combining Forces

By: Martin McEachern
The best of the Lucas empire—game developer LucasArts and feature-film production company ILM—.joined forces to create the stunning scenes in the computer game Star Wars Bounty Hunter.

In Star Wars Episode II: Attack of the CThe best of the Lucas empire—game developer LucasArts and feature-film production company ILM—.joined forces to create the stunning scenes in the computer game Star Wars Bounty Hunter. lones, bounty hunter Jango Fett secured a pivotal role in that storied galaxy far, far away when he fell under the command of the nefarious Count Dooku and became the prototype for the clone army of the Republic. Now, the Mandalorian mercenary is assuming an equally important place in the history of George Lucas's effects empire by uniting Industrial Light & Magic (ILM) and LucasArts for their first joint endeavor: a thrilling third-person action game that plunges players into the role of Jango Fett and into the dark, deadly underworld of a bounty hunter.





In Star Wars Bounty Hunter, developed by LucasArts for the Sony PlayStation 2 and the Nintendo GameCube platforms, fans join the ruthless clone ranger on a quest that bridges the events in Episode I and II. In an effort to elevate the game to the pedigree of the films, LucasArts enlisted ILM to produce 18 rendered cinematics, comprising more than 300 shots, to advance the game's story. Through the production, ILM and LucasArts established a new pipeline for the storage and sharing of digital assets, demonstrating the growing synergy that's emerging between film and gaming.

Players of the game assume the role of bounty hunter Jango Fett (top left) and must negotiate six unique worlds, such as the run-down spaceport known as Outland Station (above).
Images courtesy LucasArts.




In Bounty Hunter, Darth Sidious's sinister plot to establish his empire by igniting an intergalactic war is threatened by a mysterious cult known as the Bando Gora, whose "shadow" assassins are slaughtering industrial leaders selected by Sidious for key positions in his planned regime. Sidious charges his apprentice, Dooku, with eradicating this threat and finding an ideal specimen to serve as the genetic template for a clone army to overthrow the Republic. Dooku resolves to accomplish both tasks by placing a generous bounty on the head of the Bando Gora leader—a rogue Jedi named Komari Vosa—and using the successful bounty hunter as the host for the clone army.





The "back story" game, written and directed by Jon Knoles (see "Gaming's Next Episode," pg. 44), reveals how Jango captures his prey to become the prototype for the clone soldiers. Along the way, he negotiates 18 levels spanning six unique worlds, beginning in a run-down spaceport called Outland Station, whose levels include a pit arena for fights, a crowded marketplace, and a hectic cargo conveyor system.

With the visual diversity in those environments, LucasArts' first challenge was to establish a consistent and cohesive look to the game. Rather than aspiring to photorealism, the Bounty Hunter concept artists aimed for the vibrant, comic-book style reflected in the paintings of veteran Star Wars artists Ralph McQuarrie, Joe Johnston, and Doug Chiang. The game's settings were designed to exhibit a mixture of high technology and primitive architecture steeped in the worn and weathered look that is the hallmark of the Star Wars canvas.

According to LucasArts lead artist Ian Milham, the most demanding environments to texture were the vast cityscape of Coruscant and the congested, Hong Kong-style "hives" of Outland Station. In re-creating Coruscant for the game, the artists had to texture surfaces that were monumental in size yet avoid a tiled, repetitive look. "We needed to achieve a busy, chaotic environment without exceeding the memory limitations of either game console," says Milham. "So we concentrated our texture memory in a few high-profile areas, using eye-catching, highly detailed animated textures [such as for electronic signs] in well-lit areas, then filling in the shadowy areas with lower resolution images."

The artists used customized shaders to achieve the light rays and the overall murky atmosphere for the level known as Malastare.




To maximize the capabilities of the PS2 and GameCube, the artists separated the texture pipelines of the two platforms. This enabled them to incorporate 24-bit textures into the GameCube edition, and downsampled 4- and 8-bit textures into the PS2 version, whose texture memory capacity is far smaller than that of the Nintendo console. By using the smaller textures, the artists were able to fit more textures onto the PS2 surfaces than would have been possible with the much larger GameCube versions.

Furthermore, the PS2 and GameCube editions were outfitted with entirely different graphics engines, customized to exploit the unique strengths of each platform. By taking advantage of the PS2's huge Direct Memory Access bandwidth and providing texture MIP mapping and full-screen anti-aliasing, the group was able to incorporate an exceptionally high number of textures into the game. The artists also maximized the performance of the PS2's two vector unit chips, using the second chip for character skinning and optimized render loops, while dedicating the first chip to skeletal animation, thus allowing dozens of characters to appear on screen simultaneously without slowing the frame rate. Although the graphics engine can draw 10 million triangles per second, after adding gameplay, collision, logic, sound, and so forth, the PS2 edition ultimately moves around 30,000 to 50,000 triangles per frame, at an average rate of 30 frames per second.

The GameCube graphics engine, on the other hand, adds projected shadows and up to 50 percent more polygons to all the characters. It also capitalizes on the system's faster CPU to boost the frame rate to 60 frames per second, and utilizes its texture compression ability to deliver high-resolution textures with improved color variance.

The texture maps for both versions were created in Adobe Systems' Photoshop, then applied to any one of a series of specially designed shaders that tell each console how to use the alpha channel of the texture to modify the surface's reflectivity, transparency, specularity, or other attributes during gameplay. These shaders were critical in texturing the swamps of Malastare, whose murky atmosphere depended less on texture variety and more on resolution and alpha-channel effects, such as for simulating "God rays" slicing through the veil of thick fog. The artists also added layers of background paintings at the edge of the Malastare jungles that were coordinated with the camera's distance and viewing angle to maintain the illusion of depth.

Because of memory constraints, the lighting effects that enliven the six worlds could not be achieved with light maps. So LucasArts created its own in-house renderer, Flux, to paint lighting directly onto the vertices. "We lit the world normally in [Alias|Wavefront's] Maya, using directional, ambient, and point lights, then baked the lighting into the vertices with Flux," says Milham. "We also created a robust set of tools for modifying the brightness, saturation, and hue of any group of vertices after they had been lit."

The artists also used another proprietary tool, VFX Editor, to create multi-layered sprite and particle imagery, including the combustive exhaust from Jango's jet pack and the streaming fire from his flamethrower. "Each object contains a collection of envelopes, or functions, for controlling the position, scale, ARGB (alpha/red/green/blue) channels, and other attributes over time," says senior programmer Chris Barnhouse. "This gives artists command over every aspect of the effect, which can then be applied to any model and set to play continuously or when triggered by a certain action."

While the VFX Editor was powering Jango's artillery effects, the modeling and animation crew was giving Jango the cat-like agility he needs to elude enemy fire and navigate the game's complex worlds. The character can dodge, jump, roll, hang from ledges, crawl through tunnels, dive with both guns blazing, or perform aerial acrobatics while jet-packing over dangerous chasms. Jango, composed of approximately 2700 polygons in the PS2 version and 7500 polygons in his GameCube incarnation, joins rival bounty hunter Zam Wesell, Komari Vosa, Montross, Count Dooku, and Rozatta (a Watto-like Toydarian) as the game's star models. In addition, there's a large supporting cast of lower resolution characters and creatures, both familiar and unfamiliar to fans.

To recreate the faces of the Attack of the Clones characters, the artists referenced photos of each actor while hand-sculpting meshes and hand-painting textures that matched the "rendered" quality of the game. The digital actors were modeled to appear slightly younger than their movie counterparts, which is one reason LucasArts chose not to digitize their faces. "Using scans also would have given the characters a strange, mannequin look in the game, often making them seem more fake," says Knoles. "Furthermore, they would have inherited the lighting used in the scanning process, which may not have worked in most lighting situations within the game."

For a range of expressions, LucasArts rigged the characters' heads with bones and Set Driven Keys for phoneme and muscle movements.




Since Bounty Hunter called for many of the characters to appear simultaneously on screen, the team implemented an efficient level-of-detail (LOD) system to optimize the use of polygons according to the complexity of a scene and the camera distance. For a basic biped character, the artists created three levels of detail, comprising 1000, 500, and 250 polygons.

Bounty Hunter's in-game playable characters, with their simplified hands and faces, were bound to skeletons containing 27 to 35 bones. However, for the prerendered cut-scenes, LucasArts provided ILM with augmented character rigs, adding approximately 35 additional bones to more fully articulate their hands and faces. The arms and legs of both sets of rigs were operated with a full complement of IK switches, while the sinuous motion of tails was achieved through IK spline handles. Both sets also shared a hand and face setup consisting of Maya Set Driven Keys (for storing a library of simple and easy-to-edit movements) and IK handles to tweak certain shapes into specific positions.

Like their counterparts performing in the cinematics, many of the in-game characters required extensive facial animation and lip synchronization. According to technical director Jeremie Talbot, the challenge of keeping these animations fast and clean enough for the game engine to run in real time was handled efficiently by the bone/Set Driven Key facial setup.

For the lip sync, the animators used Puppetworks' Voiceworks plug-in for Maya, then operated more than 30 muscle-based facial controls to refine the various mouth and facial movements.

ILM's 18 rendered cinematic cut-scenes, shown before and after each chapter, evolved through a typical film-like production process that included both videomatic and animatic stages. Most of the camera and staging setups developed at the animatic level were used verbatim at the animation level.

While all of LucasArts' in-game polygonal character models were appropriated for the cinematics, ILM subdivided and smoothed the meshes considerably, occasionally enhancing a texture map and remodeling some objects in greater detail—Jango's helmet, for instance—for close-ups. The cockpits of the ships and most of the sets and props seen in the sequences were also built by ILM using Maya, Softimage, and ISculpt (the studio's proprietary tool) for modeling, and Photoshop and Avid's Matador for painting textures. In fact, the exterior of Jango's Slave I ship was the one prop that was directly imported from the Attack of the Clones film into the cinematics, marking the first time a digital asset from a Star Wars film has been repurposed for a computer game.

Jango's rival, Montross, is a high-resolution main-character model with a skeletal structure containing 30-plus bones.




While ILM worked from concept art and storyboards developed by LucasArts, the staggered production schedules of the two companies often allowed ILM to finish sets and models for their cinematics before the corresponding level geometry had been constructed for the gameplay. In such instances, LucasArts' level designers would use ILM's models as a guide for their own. For example, ILM was able to pass on their models for the interior of Outland Station's fight arena as well as Komari Vosa's meditation and torture chambers, allowing the film artists to bring their talents to bear on the gaming environments.

While animating the models in the cinematics, ILM animators Greg Kyle and Jay Rennie preserved LucasArts' facial rigging so they could employ the same Voiceworks automated lip-syncing technique as the game developer, thus ensuring a consistency between the gameplay mouth movements and their own. This was ILM's first experience using the Maya plug-in, and it quickly proved to be a powerful tool for removing the drudgery of breaking down sounds into bar sheets. ILM animation director Paul Griffin estimates the group saved approximately 140 man-hours by using the Voiceworks plug-in.

The team at LucasArts used its proprietary VFX Editor to create particle-based imagery, such as the the combustive exhaust from Jango's jet pack.




Nevertheless, since the game's hectic production schedule spared little time for acquainting ILM animators with LucasArts' IK setups for the bodies, Griffin chose to convert some of the IK rigs to a style similar to the one used at ILM. The most significant modification involved the addition of expression-based macro controls that let the animators quickly shift the center of gravity, pose the chest or hips, or manipulate other parts of the body while implicit adjustments were made to the skeleton.





All told, the ILM animation crew, which fluctuated between six and 25 people, generated 20 minutes of finished animation, plus outtakes, in 11 weeks. At a resolution of 640 by 272 pixels, the animation was specifically rendered to resemble the style of a graphic novel, which blended nicely with the painted, comic book-style LucasArts sought for its gameplay graphics.

Though the two companies wanted the cinematics to outshine the gameplay graphics—as a reward to the game player for completing each stage—they took several steps to ensure cohesiveness to the imagery. First, ILM used as many of LucasArts' gameplay props and textures as possible. Second, ILM CG supervisors Doug Macmillan and Euan MacDonald established a look and lighting standard for each sequence that adhered to the corresponding gameplay environments. And finally, while render tests and animations were constantly shared and compared via an ftp conduit, a team from LucasArts visited ILM several times a week to review their work and ensure consistency between each other's versions of characters, props, and sets.

Star Wars Bounty Hunter is heralding a new era of increased collaboration between film and game artists. The offspring of two previously incompatible industry giants, the title has led to the assimilation of each other's numerous tools and the interchangeability of their many respective skills. Working closely with ILM gave LucasArts an opportunity to absorb ILM's techniques for lighting, staging, and organizing scenes, then apply that to 56 engine-driven cinematics it created to supplement ILM's prerendered cut-scenes.

ILM created 18 pre-rendered movies for the game, using many of LucasArts' in-game characters, which were often enhanced for the cinematics.
Images courtesy ILM.




In addition to embracing Voiceworks for facial animation, ILM's foray into video games resulted in the development of new Maya rigging techniques, a suite of streamlined tools for resolving high-speed production issues, and a new tool for automatically dropping shots into a scene as soon as they've been rendered, eliminating the need to manually assemble the shots on a non-linear editing system before viewing the cut. In fact, many of these tools are now being rolled into ILM's feature-film work.





Creating the cinematics also proved an empowering experience for many of ILM's artists, who, in contrast to assuming specialized roles in their film work, found themselves operating several stations in the animation pipeline. Moreover, the project has given ILM, a company accustomed to harnessing a wide variety of proprietary and off-the-shelf software for creating its blockbuster film effects, the experience of using Maya as a single-source production tool, demonstrating to software companies the value of including game-specific tools within their packages.

"Through the making of Bounty Hunter, it will be much easier to share our assets with LucasArts in the future," says ILM's Griffin. "I can see the day when computer games are truly the enabler of interactive digital cinema. It makes sense to build a master set of models, animation rigs, and materials that can be shared between us." While that goal may still loom beyond the reach of current technology, the two companies' once-divergent production pipelines are obviously beginning to converge. ..

Martin McEachern, a contributing editor for Computer Graphics World, can be reached at martin@globility.com.




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