The tech behind Disney’s ‘Frozen’

By Ysabel Yates

The Walt Disney Co. has been inspiring audiences for generations. Every piece of a Disney production comes together to make each film unique and unforgettable: the storytelling, the songs, the characters inspired by folklore and, of course, the animation. That final piece is where the studio has always been able to stay ahead of the curve.

Take “Snow White and the Seven Dwarves.” When it came out in 1937, it was the first feature-length animated film where each frame was hand-drawn, a technique called cel-animation. The ambitious feat nearly bankrupted Walt Disney, but when “Snow White” hit the box office, the hard work paid off: Adjusting for inflation, it continues to be one of the top-10 grossing films in North America.

Cutting-edge animation

The Disney productions of today continue this cutting-edge tradition. The most recent example of this comes from “Frozen,” Disney’s Oscar-winning musical based on Hans Christian Andersen’s “The Snow Queen.” Disney animators turned to simulation-based engineering, the same computer simulations used to predict the effects of building explosions, In order to get the realistic snow in the film.

Called Material Point Method, the simulations were developed by researchers at the University of Missouri using a $400,000, five-year CAREER grant from the National Science Foundation. The simulations, developed 20 years ago, are consistently being tweaked by teams of researchers all over the globe to model real-world scenarios such as explosions, impacts and fires.

The information gained from the simulations helps inform designers on how to improve the construction of buildings, such as reinforcing walls, columns and windows. In “Frozen,” the simulations were used to add realism to snowball collisions and the snowy backdrops. You can see a video of how the simulation was used in “Frozen” here.

From snow to curls

Material Point Method isn’t the only computer simulation making animated films more realistic. A team of researchers from MIT and the Universit Pierre et Marie Curie in Paris have developed a 3D model for a strand of curly hair. Animated characters had curly hair in the past — Merida in Disney/Pixar’s “Brave” comes to mind. But even Merida’s hair, which was generated using a simulator named Taz, wasn’t true to form. Instead, Taz simulated individual coils around computer-generated cylinders for Merida’s hair.

The latest 3D model “characterizes all the different degrees of curliness of a hair and describes mathematically how the properties of the curl change along the arc length of a hair,” says study co-author Pedro Reis, an assistant professor in MIT’s Department of Civil and Environmental Engineering and Department of Mechanical Engineering, in a university statement.

The researchers didn’t initially set out to model curly hair. Rather, the study was meant to investigate the natural curves of flexible tubing. But once investigations started, Reis realized that tubes weren’t so different from curly hair. Following this, the model can be used to predict the behavior of not only hair, but also steel pipes and suspended Internet cables.

Like the Material Point Method, the 3D model may one day find its way into Disney films to make the magic just a little bit more realistic.

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