After five years of playing with clay, director Nick Park has taken the duo Wallace & Gromit to places Gumby and Mr. Bill never thought possible. But even he realizes the primitive art of claymation can benefit from the modern conveniences of a little computer-generated animation.

'"There are limits to Plasticine," Park says as he prepares for the nationwide release Friday of "Wallace & Gromit: The Curse of the Were Rabbit," his latest all-clay – or should we say mostly clay – kiddy comedy.

"You can't do fog or smoke or water. I mean, you could, but it would take forever, so we went to The Moving Picture Company to create our visual effects."

After the $172 million success of "Chicken Run" in 2000, Park has reason to feel confident that today's kids – who might as well be known as "The CGI Generation" – have the same affection for crude clay filmmaking as their parents. His Oscar-winning "Wallace & Gromit" shorts have achieved cult status and are a big hit on DVD.

In many ways, Park and his team at Aardman Animations are making "Wallace & Gromit" just as Park did when he began sculpting the Plasticine duo in 1983, as a student at Britain's Beaconsfield Film School. Of course, he's now working on a scale as elaborate as one of Wallace's inventions.

So Reliable, So Re-Pliable

In the new film, Wallace and Gromit guard their little British hamlet from vermin as proprietors of "Anti-Pesto," an extermination service. Wallace humanely captures garden-ravaging rodents with his Bun-Vac 6000, and his faithful dog, Gromit, keeps the critters in their basement, proving he's a true canine humanitarian.

To depict the epic battle with the Were-Rabbit, Park's team constructed a set with 400 clay puppets at a warehouse-sized set in Bristol, each figure formed from a metal skeleton and covered with a synthetic blend of clay they call "Aard-mix."

The clay figures are molded for each shot, and with 24 individual frames required for each second of film, it's easy to see how the 85-minute feature was five years in the making. It might be nice to program a computer to do that work. But the Aardman team believes audiences appreciate human effort – and human imperfections.

"You can see the fingerprints," says Producer Peter Lord of the cheese-loving inventor and his long-suffering pooch. "It tells you that they are real. They are tangible."

"Chicken Run" was made in a similar fashion. But Park now thinks that production was a little too slick. He's since gone back to the more rugged look of early "Wallace & Gromit," and that has hardly compromised the project.

With the first commercially released "Wallace & Gromit" short, 1991's "A Grand Day Out," Park proved that claymation could effectively and comically depict a lighthearted space race, where Wallace hoped to feast on the moon's abundant supply of cheese.

In the new film, CGI helped to illustrate some of Wallace's new inventions, including his brain-sucking Mind-O-Matic. But deciding just how much high-tech wizardry is right for decidedly low-tech claymation can set filmmakers on a slippery slope as steep as Gumby's forehead.

"We're not biased toward any one technique," says screenwriter Steve Box. "We used CGI for things like water and smoke and dust and dirt, and it added so much to the film. The way the vicar walks down the path toward the church and the fog swirls behind him. Gone are the days of cotton wool on strings."

For more sliver screen glitz, Helena Bonham Carter supplies the voice of Wallace's new love interest, Lady Tottington, and Ralph Fiennes plays the follicle-ly challenged bad guy.

Now, as the carrot-chomping were-rabbit bears down on this little clay village, Park and company have to hope their vegetarian monster has just enough bite to thrill kids, entertain parents and fill box offices with plenty of Play-Doh.