The hero of Kung Fu Panda , destined to be a hit movie this summer, may have the voice of actor Jack Black. But the appearance of Po the panda and his co-stars is the work of 2,200 computer systems.

DreamWorks Animation SKG's compute farm handles most of the heavy lifting involved in creating an animated movie. The computers become the studio lot, the sets, the sound stages and the lighting cameras, and even the preview screens used by the director to decide on the final cut.

As both animation and computer technology has advanced, so the compute farm has grown.

In 1999, DreamWorks had 140 computing cores, but as costs have fallen, the company greatly increased its processing and rendering capabilities. Three years ago, the compute farm switched to 1U rack servers, but these have mostly been replaced with blade servers from Hewlett-Packard, which offer significant advantages in power efficiency.

For the animators, though, power consumption is less interesting than raw computing power. More processing power allows animators to create more dynamic and more realistic films, but also keep to the studio's demanding release schedules. Effects such as water, hair, or in Po's case, fur are very demanding in terms of processing resources.

Unless studios can process more frames in the same or less time, adding the richness to the latest crop of animated films would simply take too long. For the studios, keeping up a schedule of releases is vital if movies are to make a profit.

DreamWorks Animation has produced a string of hit movies, including the Shrek series, Madagascar and most recently, Bee Movie . With Kung Fu Panda now being released, studio resources are being switched to the sequel to Madagascar , and the next instalment in the Shrek franchise.

Managing the often conflicting demands of movies in different stages of production is down to senior technologist, Scott Miller. The company uses load sharing facility scheduling and management software from high-performance computing specialist Platform Computing, not least because of its Fair Share resource allocation functions.

"We have a 'hard partition' for each movie," says Mr Miller. "We have a share for each movie, and for each department within each movie. The movie that is in the most intensive phase [of production] gets the most resources.

"So Kung Fu Panda had 90 per cent, and now Madagascar II has 90 per cent. Everyone in the studio is working in the same direction, but the most important movie is always the next movie."

A typical 90-minute feature film contains 125,000 frames of animation, or between two and a half and three terabytes of data. But before the final cut is rendered, ready for duplication on to 35mm film or to disc for digital cinemas, a movie will consist of about 45 terabytes of pre-computed caches of scenes and working copies, mostly at a low resolution. "Kung Fu Panda had a total footprint of about 50 terabytes," says Mr Miller.

Allocating the right computing resources to each film, and to each stage of its production, is critical if film-makers are to have the creative flexibility they need but still keep to the release schedules agreed with the distributors and cinema chains.

"We can't overrun," Mr Miller says. "We told people our release date two years ago. We pick a due date and allocate resources accordingly."

As a film moves through production, any changes become harder and more costly, because of the labour involved in reworking frames in the compute farm. After the initial creative work and storyboards, each film moves to a story reel, which is the whole movie, including scratch dialogue and music.

Then the animation team works out each sequence, in terms of its location, and each shot down to the camera angle. After that, the film moves to layout, cinematography, animation and lighting. At each step, the movie's resolution increases.

"Most changes take place in the story part of the process," says Mr Miller. "Changes in lighting are the most disruptive."

But it is also the lighting and other effects, such as textures, that make today's computergenerated animations so captivating visually, even if the voices are still provided by actors.

"Movies such as Toy Story [an early computer-generated animation] had static backgrounds and lighting that did not interact with different objects," says Mr Miller. "In Kung Fu Panda , we have a lot more long hair, fur and clothes. We did that because we could; 10 years ago we could not."

As a result, the number of CPU or computing hours needed to create a movie has grown from 5m for an early-generation animation to 25m for Kung Fu Panda . But the pace of production has increased too: the studio makes two films a year, despite all the additional detail required.

"We know what we are doing until 2012," says Mr Miller. "The compute grid lets the animation be more complex, and also lets us make more films." The constant efforts to improve the level of detail in the computer-based animation also allows the storywriters to put more of their imagination on screen.

The writers behind Shrek , for example, documented their green hero's world in an extensive style guide, even before technology advanced far enough to put much of that detail on screen.

"There is a conscious effort to do something more compelling, even if we start a movie without knowing how we will finish it," Mr Miller says. "If we insisted on using today's technology in 2011, we would be bored. One of the few constant technologies has been the LSF software, used by the studio from the start because, as Mr Miller says, it is "fire and forget", and it will continue to be used for as long as it helps control what he describes as a "digital sprawl" of increasing computing capabilities.

Despite sometimes likening the process to a "digital arms race" between studios, Mr Miller believes the investment has paid off in the way that matters most: on the screen and at the box office.

Mr Miller comments: "We could have a shorter time to do a production, but it usually leads to more iterations [of a movie] and a better picture."