Andy Gent says it was clear as soon as he read Wes Anderson’s script for “Isle of Dogs” that the project was very ambitious. It just took a while to understand exactly how ambitious.

For example, it was originally estimated the animated movie would require between 300 and 400 puppets, the same number needed for Anderson’s previous stop-motion feature, “Fantastic Mr. Fox.” But giving the movie the scale and look Anderson wanted quickly inflated that number to more than 1,100.

”He pushes you to levels that are amazing levels,” says Gent, who was head of the puppet department on both “Isle of Dogs” and “Fantastic Mr. Fox.” “Out of that push to do something new, new things would eventually pop out and they could be very happy accidents.”

Anderson wanted his canines to have a bit of humanity in their faces, but aside from more expressive eyes and the ability to talk, the puppets were to mimic canine anatomy and motion. The dogs all were intended to be mutts instead of specific breeds. “We sculpted hundreds of different versions and we would pick and choose between them,” Gent says.

Building the puppets starts with a mechanical armature made of a variety of metals from brass to titanium alloys, with ball-and-socket joints. Fiberglass skulls and modeling clay-silicon tongues are added, along with silicon muscle and flesh. Mohair and alpaca fur of the type used for teddy bears is cut and glued onto stretchable nylon fabric using medical adhesive.

Fur has always been a challenge for stop-motion. ”You avoid it like the plague because it’s just difficult to do,” says Gent. “We tested all manner of gels in the fur to stabilize it, but of course Wes would want it to flutter and move around so we had to learn ways to animate the fur.”

For example, the puppet for Nutmeg has long fur anchored to her head that goes down past her chest. “The animators have to learn this technique of placing their finger on the same place every time, pushing it back and then moving the puppet,” says Gent. “It takes an incredible amount of patience.”

The process from an approved sculpt to finished, animatable dog puppet took about 15 weeks for most characters, though some, like Nutmeg, took as long as 20 to 30 weeks to get right. Dogs were built in five scales, from a one small enough to fit entirely on a thumbnail to a mouth needed for a closeup that was large enough for someone to climb into, Gent says.

For the human characters, Anderson wanted a new look and the production quickly focused in on using a translucent resin to replicate the glow of real skin. A face-replacement system was used, but each face had to made by hand in a laborious process that required multiple molds to get the final face. A mistake anywhere along the process meant starting over

“Every face you see in the film has been done two or three times to get to the one that actually made it on screen, and there are thousands of them,” he says.

Gent says the film tested his expertise in just about every way possible. ”Over 20 years of making puppets and working in stop motion … it was all put to play on this film.”