Behind the stunning stop-motion magic of 'Kubo and the Two Strings'

Director Travis Knight reveals how the puppet masters at Laika combine CGI, 3D printing and other high-tech techniques with time-honoured stop-motion storytelling.

Richard Trenholm Former Movie and TV Senior Editor
Richard Trenholm was CNET's film and TV editor, covering the big screen, small screen and streaming. A member of the Film Critic's Circle, he's covered technology and culture from London's tech scene to Europe's refugee camps to the Sundance film festival.
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Richard Trenholm
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Laika/Focus Features

Amid a deluge of CGI movies, "Kubo and the Two Strings" could be considered something of a throwback. But while it was made using the time-honoured technique of stop-motion puppetry, it also relies on cutting-edge technology.

"Kubo" is the latest stop-motion movie from animation studio Laika, maker of "Coraline", "ParaNorman" and "The Boxtrolls". Those three films were nominated for Oscars in the animated-film category, and reviews give "Kubo" a solid thumbs-up with an aggregate score of 84 on Metacritic. I met with the film's director, Travis Knight, to find out how the stop-motion fans at Laika embraced "the infernal machine" of computer-generated imagery, and why "Kubo" balances dark and light.

The film, which just opened in the UK after an August release in the US and Australia, takes viewers to ancient Japan to tell the story of Kubo, a young boy with magic storytelling powers that bring his origami creations to life. Aided by a motley band of friends, Kubo must face the sinister Moon King in a series of magical escapades.

It's a joyous adventure seasoned with thoughtful themes, and comic voice acting from Charlize Theron and Matthew McConaughey adds life to remarkably expressive characters. Plus, it looks absolutely stunning.

In stop-motion, animators pose puppets and capture a still photo. They then move the puppet for the next photo. Playing back the resulting photos as frames of a film creates the illusion that the puppet is moving. For "Kubo", Laika made around 200 puppets.

"They're engineering marvels," director Travis Knight said of the puppets. "They have these little metal skeletons so we can pretty much put them in any position and they'll hold those poses...The wigs, which are all made by hand, are actually human hair that we comb through with silicone to give it durability, and then put in little wires and glue to make it animatable."

Stop-motion has existed as long as cinema itself, but with the advent of CGI it seemed like traditional techniques were obsolete.

"The computer could do everything we could do in stop-motion, but better...greater flexibility with fine-tuned precision," Knight recalled of his early years as an animator in the 1990s. He calls computers "the infernal machine" and describes how the team at Laika resolved "not only to make peace with [CGI], but to learn to love it, to embrace it, like a Luddite would embrace the loom."

Animators used computer-generated digital effects to fill in or extend backgrounds, add extras to crowd scenes or paint out wires used to support some models. But everything starts with puppets. "No matter what we do we always build it as a practical thing first. Even if we're going to build it digitally we give [the practical model] as a reference to our digital team."

For example, one sequence sees Kubo and his friends take to a vast lake. "Stop-motion and water are things that don't go well together," Knight said, "so we did some initial tests with rippled panes of shower glass that we would move against each other to try to see how the light would work. We used cloth, garbage bags and shower curtains on big metal grids and moved them around in an undulating way to see how that would simulate water."

Those tests were then given to digital animators to create the finished shots.

"We're not purists about stop-motion," Knight said. "If there's a tool we can use that makes more sense to bring something to life in a better way, we'll use it, whether that's hand-drawn animation or CG or some newfangled technology we're developing. There are some shots that are entirely practical. There are shots that are almost entirely CG. And then there are some shots that are blended."

Knight says some filmmakers use CGI as a crutch, but it's one his team can't lean on as stop-motion animation requires meticulous planning for literally every frame. "There's the old saying, 'we'll fix it in post', hoping someone else will solve the problem later. That's never something that we can do."

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The characters of "Kubo" are remarkably expressive.

Laika/Focus Features

The Laika team didn't stop at embracing the computer. They adopted and adapted other technology, including stereoscopic photography, laser-cutting, 3D printing and rapid prototyping to create ever more sophisticated models in ever shorter times.

"In 'Coraline', you really couldn't do anything on the fly," Knight said. "We needed somewhere between a two-, three- or four-month period for making changes to faces. With the way the technology and our processes have advanced, you can now get a new face in a matter of hours."

However, "you can't just pop them onto a puppet," he admitted. When a new face for a puppet comes out of the 3D printer it has to be cleaned, dipped into a vat of superglue to test its durability, and hand-painted to look more organic.

"We fuse craft and art and science and technology together in a big roiling gumbo of techniques to try to tell stories in the best possible way," Knight said, "because fundamentally that's all what technology is: a tool in service of its operators."

The most complex creation in the movie is a giant skeleton beast with flaming eyes. The puppet was a combination of high-tech and lo-fi techniques, standing on what the team dubbed a hexapod, a computer-controlled platform similar to the system that moves a flight simulator. "But then it was also an enormous marionette, where the monster had cables attached to its wrists that would be strung up to the ceiling and then dropped back down, held together with big plastic buckets filled with sandbags."

The puppet stood 18 feet (5.5 meters) tall, with a wingspan of 23 feet (7 meters). "We had clusters of magnets keeping the arms together with the shoulders. We used industrial, architectural, high-density foam to create the bones to be as light as possible. Even still the thing weighed 400 pounds (180 kilograms). The elbows were held together by automobile brake pads. We went through three sets of brake pads over the course of the film."

Knight is proud of the sense of "unbridled joy coursing through the film." But he doesn't shy away from balancing the fun of the story with deeper themes and darker moments.

"We come from a tradition of storytellers that include classic Greek myths, fables, the Disney films of the '30s, '40s, and '50s, even the Amblin films of the '80s," he said, "and the thing that unites those storytellers is they understood the best, most enriching stories balance darkness and light, intensity and warmth, humour and heart. Spending a little bit of time in the shadows makes the light that much brighter and warmer and more beautiful."

Knight believes the stylised prism of animation gives storytellers an opportunity to teach as well as entertain. "If you can do things in a stylised and hopefully poetic way," he said, "I think it's easier for a kid to understand and to try to contemplate and reconcile. Those film-going experiences I've had with my children where we've watched a movie that goes into the marrow of some of these important issues, where we're on the ride home talking about the things it's brought up, those are my favourite kind of experiences -- those are the kinds of experiences we want to create."

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"Kubo" combines stop-motion puppetry with cutting-edge CGI.

Laika/Focus Features