Computer Graphics World

December 2008 42 ■ ■ ■ ■ CG I One model that especially challenged the group was not a character, but a palace throne room, which had to be destroyed in a final sequence. "It's one thing to model a structure for animation, but when it came time to break parts of it off, we realized there were a lot of subtle things that had to go into making it believable," Grubb says. First, the team cut out pieces of geome- try to make the "parts" seem as if they were broken out, but this produced a "cheap, toy appearance," Grubb recalls. e artists then created subsequent versions by adding more substructure—such as different types of stone and mortar, reinforcement bars, bricks, and even bits of broken and cracked plaster and stone around the edges. As for texturing, the artists began the process by creating a library of images that formed the basis for the color palettes and textures that would be representative of the two major character races. For charac- ters, they wrote MEL scripts to help with the UV layout process, and used Adobe's Photoshop to paint the surfaces, adding ef- fects and filters to give them natural variety and a painterly hue and tone. Environmental Impact e epic-size environments and sweeping vistas are lush, beautiful, and colorful, with a soft fantasy-like appearance. Although they may look like matte paintings, most of the backgrounds began as 3D models and were later intensified with painted de- tail. "e way we lit the backgrounds made them look more painterly. We took things like a sky and clouds on mattes, and placed them onto a dome inside Maya, then color- corrected the layer. is gave us one mas- sive painting that we tweaked for various scenes," says Adler. "Again, we used what we had and modified it as much as possible to take things as far as we could." e environments often are teeming with foliage, grasses, and moss, all grown with Joe Alter's Shave and a Hair- cut. Procedural textures were used exclusively for these elements, making them more resolution independent for both close and long shots. e film also con- tains a good amount of clouds and smoke, cre- ated with Maya Fluids. As Grubb explains, the characters had to move through each—the flying Razorwings through the clouds, the ground dwellers through the smoke and fire. To avoid the problems inherent in rendering meshes within Maya containers, the artists used depth and normal renders of the characters and set elements to place them within the volumes during compos- iting, which occurred within Adobe's After Effects and Apple's Shake. is also gave them more control while manipulating the density and placement of those effects. e group also used a variety of proce- dural techniques, particularly in one scene that proved to be deceptively difficult. "We started out just modeling tubes of caverns, but they looked too simple and bland; to make them more believable, we added lots of rock and cracks, but the sets were get- ting incredibly dense," says Grubb. "So we ended up using a procedural particle re- placement to add a variety of stones to the walls of the caverns at render time, so the models were light for animation and base lighting, and would render quickly with the instances added in the final frames." Taking Control Due to financial considerations, the group used the renderer inside Maya. "It's free," notes Adler. "But we did have to be more creative in getting the overall look we want- ed out of that renderer." So they leaned heavily on the lighting team to come up with the desired look for the movie. Because the tool did not offer a lot of flexibility out of the box, the group ren- dered in layers, using a good deal of RGB and normal maps to control the images in comp. "is gave us a lot of control over the color and effects, and it let us achieve a uniform, painterly look via Shake mac- ros, which let us dictate the light bleeding, blooming, and other effects," adds Adler. DrQueue open-source software automat- ed and managed the rendering process. is was done on a Linux-based renderfarm of 1000 CPUs, some donated by AMD. Perhaps the biggest technical investment the group made was in the creation of a pro- prietary Web-based asset management and collaboration tool, dubbed Storyline, that tracked the film's 1500 shots from layout, through animation and comp'ing, to final output. e visual system enabled any art- ist, regardless of location, to browse a series of thumbnail images and access the desired sequence. By clicking on a shot in that se- quence, the person is presented the shot along with a range of information about it. "We could track the shots through the different steps in the pipeline, and with a button click, we could look at a shot and determine where it was in the overall pro- cess," explains Grubb. By focusing on the end result rather than on a particular tool, the group at Fathom Stu- dios was able to turn a dream into reality. ■ Karen Moltenbrey is the chief editor of Computer Graphics World. The majority of the environments are 3D models enhanced with painted detail. Lighting intensified the aesthetic.

• Cover