In creating its newest animated film, "Up," Pixar had to develop a technique for animating more than 10,000 interdependent balloons. The studio turned to its computers to make it work.
Daniel Terdiman
Daniel Terdiman is a senior writer at CNET News covering Twitter, Net culture, and everything in between.
In Pixar's new film, "Up," the studio faced the challenge of how to animate more than 10,000 interdependent balloons. In the film, Pixar's tenth feature, the balloons needed to behave realistically, which meant that if one bumped into another, the second one would move.
And this interdependence had to include all 10,000 in the cluster. The studio couldn't hand-animate the balloons, nor would traditional computer animation work. Instead, Pixar's animation and computer experts crafted a procedural animation technique that let them achieve the look they wanted.
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Progression 1 of 8
In this, the first of eight evolving versions of an animated scene from Pixar's "Up," we see early drawings depicting the film's two main characters--Carl and an eight-year-old stowaway named Russell--as they try to navigate a river.
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Progression 2 of 8
In the second version of the scene, we see the first round of computer animation of Carl Fredricksen, the film's 78-year-old main character, and Russell, the kid who joins Carl on his adventures.
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Progression 3 of 8
Here, we see the animators have filled in the detail on much of the background of the riverbed in the scene.
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Progression 4 of 8
Here, the animated characters are brought back in and superimposed on the newly-created riverbed.
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Progression 5 of 8
Here, the animation begins to take on a more completed look, and the animators have added water from the river for the first time.
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Progression 6 of 8
Now, many of the details of the riverbed are added, including colored flowers on one side and a much brighter color palette for the foliage behind the river.
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Progression 7 of 8
Here, the water has been removed, and the animators worked on the details of the characters' faces and clothing.
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Progression 8 of 8
Finally, all the elements of the scene are pulled together into the final version. We see ambient light added, as well as much more realistic shading and the characters' animation details. This is how the scene looks in the film.
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Interdependent balloons
"Up" revolves around the idea of using a cluster of more than 10,000 balloons to hoist a house aloft and carry it away for global adventuring. But animating the balloons was a major computing challenge, and here, with the cluster seen up close, we can see why: Each balloon has its own string, its own color, its own reflection of light, and each balloon is interdependent.
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Carl's face
Animating the film's main character, 78-year-old Carl Fredricksen, was a challenge, too. His face, designed with a cube-like shape to represent his lifelong feeling of being boxed in, required the animators to figure out how to make his facial expressions seem real.
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Feathers
Another challenge was animating the feathers on Kevin, the bird character in "Up." While Pixar has mastered animating flowing fur ("Monsters, Inc.") and underwater imagery ("Finding Nemo"), it had to figure out how to use procedural animation for something as interdependent as a bird's feathers.
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Balloon house
In this image from "Up," we see the balloon cluster carrying the house over a gorgeous canyon. This image allows us to see the full size of the balloon cluster, which was comprised of about 10,000 balloons. However, in real life, it would take more than a million balloons to hoist a house.
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Carl and Russell
This image captures both Carl's facial expressions and the balloon cluster--not to mention the childlike enthusiasm of Russell.
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Carl looks outside
This image captures Carl's sense of being at odds with the world. It shows him standing angrily at the door of his flying house as a host of other flying vehicles swarm around outside.
