Computer-generated graphics got off to a bit of a dodgy-looking start some time in the 1980s. Even with some 1990s films, your average five-year-old was not convinced. But quite a few of the big cartoon box-office smashes from about 1995 onward have taken computer animation to new highs.

Antz and A Bug's Life, released in 1998 from the two competing camps, DreamWorks and Disney/Pixar, have nonetheless something very important in common - ants. Hardly the loveable cuddily potential of soft furry animals, but ants are apparently quite easy to generate on a computer.

However, according to one reviewer, "Disney's Pinnochio of half a century ago had more individuality and visual wit than either ant epic."

In fact, the preoccupation with technical accuracy, at the expense of complex story lines and believable characters, has seen plots being written around technical effects.

Gradually, however, the ability to build in mannerisms and moods into animation programmes is coming to fruition and the genre is starting to mature. With Toy Story 2, animators have gone to phenomenal lengths to address the "sterility" of earlier films. In fact, they've gone to amazing effort to make it "dirty".

It seems that among the effects which are hard to achieve in animation is dust. According to director, John Lasseter, "We ended up making tiny little 3D particles, shaded in a soft way. I think (in one scene) there are two million of those little guys."

Two million minute scraps of perfectly formed cardboard - no wonder this sort of cartoon takes years to make. With one second of film using 24 individual frames and each frame taking over 20 hours of computer time to process, what else would you expect?

"What we do is take the editing phase and move it before the production phase, and we do it with still drawings, with storyboards," says Lasseter. "We really develop the story using storyboards. We will then make a version of the movie using still drawings, called the story reel."

When this is complete, the story reel is handed to computer animators. Once the animation is done, the scenes are lit. Computers work out how the light reflects and how shadows are formed on each object.

"One of the things that's most important about the development of the future is that . . . we always have the needs of the story dictate the technical development," Lasseter says. "It's the true blending of art and technology. The way we work is that art challenges the technology and technology inspires the art."