A Bug's Life is the product of four years' work by Pixar and Disney - the collaboration that produced Toy Story, the world's first all-CGI movie. In financial terms, the film has already squished Antz - it took $46.5m (pounds 28m) in its first two days, breaking box-office records for the Thanksgiving weekend. True, its animation is furiously inventive, but the real secret of its success is the imaginative scrip. In truth, A Bug's Life still looks like an electronic technology incursion into a physical-and-chemical medium. Like Antz and Toy Story, it has a visual texture that, after 90 minutes of staring in the dark, gives you a slight eye-ache in the way that Lady and the Tramp never did. The CGI feature is often hailed as the future of cinema, but it has a long way to go before it produces an aesthetically satisfying experience.
This becomes most noticeable when digital images are combined with live action. In Hilary and Jackie, a scene in which Emily Watson acts her socks off performing the last stages of Jacqueline du Pre's multiple sclerosis is horribly undermined by the phoney digital hurricane outside. And James Cameron's Titanic may have pitched and rolled like a real ship, but the vessel was even less substantial than the script. It looked like a moving version of a Thirties Art Deco P&O poster - only with sickly New Age add- ons such as a flotilla of fake dolphins.
Indeed, CGI replicates some of the shortcomings of more old-fashioned trickery. Like the Daleks before them, computer-generated monsters abhor rough terrain, preferring to glide across smooth, uncomplicated surfaces: the adolescent Godzillas who patrolled the corridors of Madison Square Gardens; Jurassic Park's raptors, who loved tripping across kitchen floor- tiles; those spider-crab creatures in Lost in Space, whose legs seemed to float an inch above the metal floors of their spaceship. Directors often choose to sidestep this problem by using CGI to create emphatically insubstantial objects (go-faster green jelly in Flubber; liquid metal in Terminator 2; Casper the Friendly Ghost) or flying things that don't have to make contact with human actors (airborne robotic guns in Star Trek: Insurrection; asteroids in Armageddon).
But the results aren't convincing. If you want to see how dreadful CGI can be, take another look at the souped-up Star Wars special edition, in which frail computer animations are superimposed on to rich, gritty Seventies film stock.
Of course, CGI has not yet evolved into its most efficient form. But that only makes things worse - you can see it dating before your eyes. "If every film isn't better than the last one, the audience get up and leave the theatre saying, `that sucks'," says Heather Kenyon, editor-in- chief of the Hollywood-based industry journal, Animation World Network. "The comment I heard most often about Godzilla was that there was nothing new in it, nothing that they hadn't already seen in Jurassic Park: The Lost World. These things become passe in a fortnight."
However, according to Kenyon, the rubber puppet dinosaur is due for a comeback. "The smart people have realised that models have a warm, organic quality that CGI can't replicate," she argues. It's a heartening recognition that digital technology will never completely replace physical effects techniques. King Kong may have been just a hunk of latex, yet he and Fay Wray formed one of the great romances of cinema history. And though it's difficult not to giggle when Susan Penhaligon gets flapped at by a glass fibre pterodactyl in The Land that Time Forgot, at least the scene implies that she might have got a nasty jab if the puppeteer had shoved it at her too enthusiastically. The digital Godzilla posed no such threat.
`A Bug's Life' opens on 5 Feb