By Karen Moltenbrey
Sony Pictures Imageworks may be captivating audiences with its groundbreaking computer-generated effects in the newly released Spider-Man feature film (see "Nitty Gritty Spider," page 14), but not all of the innovations are limited to the big screen. In a digital milestone, a team at Image works, working with interactive game creator WildTangent, successfully devised a method that enabled Sony Pictures Digital Entertainment (SPDE)-which oversees the activities and assets within Sony-to repurpose a robust 3D movie character for other types of media applications.
As a result, Sony has been able to promote Spider-Man on its Web site by offering fans a free downloadable screen saver and an audio visualizer (www.sony.com/Spider-man) containing an optimized version of the actual Spider-Man model from the film. These PC desktop applications, produced by WildTangent, feature the character patrol ling the city's rooftops, performing aerial acrobatics, crawling up the sides of high-rises, and using his webshooters to swing from building to building.
For years, Imageworks and SPDE have been exploring the concept of porting various movie assets for applications such as multimedia advertising and games, which would negate having to remodel characters from scratch. "We've been searching for a way to bridge the gap between what we create and what SPDE needs in terms of digital assets," says Chris Juen, digital production manager at Image works. "Until now, we had only been able to supply a gray [Maya] model but not the textures, which are generated later in the production process using proprietary software."
According to Juen, the problem has always had more to do with Imageworks' work flow processes than image-resolution requirements. Typically, the Imageworks team generates a high-resolution gray-shaded model in Alias|Wavefront's Maya, from which a lighter model is generated and this lighter model is used for previsualization purposes throughout three-quarters of the production pipeline before it's replaced with the robust model through a series of scripts. Neither model, though, contains the dazzling details that give a character its unique appearance. That's because the surfaces, highlights, lighting, shaders, and other effects are incorporated later during the texturing and rendering processes through complex proprietary software. At that stage, the models are transformed into a proprietary format, and they are incompatible with other applications.
|WildTangent integrated changeable billboards into the cityscape of Sony's PC screen saver and audio visualizer. Sony can use the billboards to promote its Spider-Man film, as well as upcoming attractions such as Men in Black II. When a user logs on to|
"Everyone wants us to provide a model as it appears in a film," Juen says, "but we've never been able to do that without incorporating our complex texturing and rendering solution." While second-party content creators could generate their own textures, they could never replicate Imageworks' minute details, so the models never looked the same.
The solution, which had eluded the group for so long, turned out to be relatively simple. Imageworks would provide a replica of its gray-shaded model along with fully rendered still images, from which the second party-in this case, Wild Tangent-would copy the textures and apply them to the 3D Maya model. "The simplicity of the approach turned out to be amazing," adds Juen. Spider-Man in Cyber-Land
Imageworks attempted to generate a workable multimedia model from its movie assets while working on Stuart Little nearly three years ago, but the model's joint structure and the studio's hair and fur pipeline that generated the textures were too complex to replicate on a non-film model. "I think that's why the concept didn't progress much since then," adds Juen. During R&D, the groups were able to export a gray-shaded Stuart Little model, even though it became slightly deformed during the conversion from Maya, used to model the character, to 3ds max, which was necessary for exporting it into a compatible Web format from WildTangent. Despite the less-than-ideal results, SPDE proudly displayed its technical achievement at the 2001 Game Developer's Conference.
Then, last year, Sony teamed with WildTangent to create a visualizer and Web-based game to promote its film A Knight's Tale, generating over a million downloads. "That, along with the reaction at the Game Developer's Conference, made us realize there is a market consisting of people wanting these types of offerings," says Shalom Mann, vice president of Sony's Advanced Platforms Group. However, since no viable cross-platform solution was available at the time, WildTangent had to create the Internet assets for the applications from scratch.
|Using its Web Server technology, WildTangent generated a five-minute looping animation for a screen saver and pulsating music visualizer that fans can download free from Sony's Web site. |
Images courtesy WildTangent.
Knowing that the Spider-Man property already had a huge fan base, SPDE further explored the technical possibilities that would enable it to accomplish a similar application to A Knight's Tale, only utilizing the film assets. This time, it was successful.
At first, the Imageworks team tried to apply a set of textures in Maya. However, this approach didn't work be cause of the complexity of both the Maya environment and the textures themselves. Instead, Imageworks consolidated its textures into a series of front-, back-, and two-side-view still images (JPG and TIF) of its fully textured high-resolution Spider-Man mod el. Along with those temporary textures, Image works also provided a copy of its gray-shaded previsualization model, which was large enough for WildTangent's needs.
The animators at WildTangent imported the Maya NURBS model into Discreet's 3ds max, and reduced the size from approximately 60,000 polygons to 6000. They also generated a 2000-polygon model for end users with less powerful PCs. Next, they imported the renderings of the textured images into Adobe Systems' Photo shop, where they tweaked the textures and combined them onto a single square texture sheet. In 3ds max, they then mapped the textures onto the final model.
Using 3ds max and Discreet's character studio, the group animated the character and generated a Manhattan-esque background-including a replica of the Sony building-through which the character runs, leaps, crawls, and climbs. Using its Web Driver technology, the WildTangent team exported the assets into its Visualizer, and integrated customized camera moves.
|The Spider-Man music visualizer analyzes the audio characteristics of a song and assigns them physical characteristics, such as certain buildings that pulsate in time to the music.|
"This was the first time we worked with an actual model used in a movie," says Wild Tangent artist Nick Trahan. "It really gave us a head start in the project, allowing us to finish in about nine weeks instead of 11."
From Sony's point of view, the biggest advantage is that it enables the company to retain the high-quality look of its characters. Mann admits, however, there is still a tremendous amount of R&D to be done on this front. "There's still a huge discrepancy between what you see in the movie and what's on the Web," he says. "It makes us realize we have a long, long way to go."
Mann, Juen, and Trahan also admit that certain factors made the Spider-Man model ideal for this process. First, Imageworks did not have to perform a lot of postprocessing to give the character its distinct look beyond the texture maps, and second, the character doesn't contain complicated surfaces such as hair or fur. "It was suitable for our current knowledge base," adds Juen. Nevertheless, the groups are optimistic about further developing the technique.
"Our technology, and digital content creation technology in general, has come a long way since we worked on A Knight's Tale," notes WildTangent senior producer Jeff Buccellato. Juen agrees: "Spider-Man kicked open the door this go-around."
While the gap remains wide between what Imageworks creates and what SPDE can use for other media, it is indeed narrowing. "A year ago we couldn't even work together [to share assets]," Mann says. "Now I wonder what we'll be able to ac complish a year from now." Excited about the prospects that can result from this achievement, SPDE is discussing follow-up projects. "Now's the chance for our divisions to work together and deploy more commercial applications that people will want and use."
Karen Moltenbrey is a senior associate editor for Computer Graphics World.