Purdue News


A QuickTime video showing the cloud animation

Purdue University

April 13, 2005

Purdue student helps movie animators take clouds to new highs

WEST LAFAYETTE, Ind. – A new animated motion picture coming to a theater near you features the work of Purdue University graduate student Joshua Schpok and faculty member David Ebert.

three-dimensional clouds
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Schpok developed the software that was used to create three-dimensional clouds in the film "Valiant," which tells the story of a small pigeon trying to do something big in Great Britain's Royal Homing Pigeon Service during World War II. The mission for Valiant, the pigeon hero of the film, is to deliver important dispatches from the French Resistance while evading enemy falcons.

"Valiant," created by the producer of blockbusters "Shrek" and "Shrek 2" and distributed by Disney, will open in U.S. theaters this summer.

"Because the film's main characters are pigeons, many scenes take place in the sky and require clouds," said Schpok, a graduate student in Purdue's School of Electrical and Computer Engineering.

Schpok adapted techniques pioneered by Ebert, an associate professor of electrical and computer engineering, to tailor the cloud-animation software for "Valiant."

"While we were developing the film, we knew that rendering clouds for the European sky was going to be another new challenge in our computer-generated animation," said Valiant co-producer Buckley Collum. "Our CG supervisor Gray Horsfield had read about early tests Joshua was doing with real-time cloud rendering. We realized that his software, with some work, could be tuned to help us provide a faster means of creating film-quality clouds within our pipeline."

The software is many times faster than conventional techniques used in the film industry to create cloud animations, Ebert said. Movie animators typically use separate software packages to first preview low-resolution images and then more complex, time-consuming software to create the final high-quality product. The software developed by Schpok, however, can be used both to create the preview images and the final high-quality images, saving time and money in the process.

Because the software is interactive, it shows results immediately, whereas conventional programs might take hours to complete such animations, Ebert said.

"With Josh's software you can design the clouds, change the way the light looks on them and move them around interactively," Ebert said.

The "Valiant" application is an outgrowth of work by Ebert and Schpok to combine simple, intuitive controls with complex mathematical algorithms – or software tools that carry out specific step-by-step tasks. Film animators and artists can use the software to make realistic depictions of cloud formations, explosions, smoke, steam, fog and other gaseous phenomena for movies and video games.

The software used to make clouds for "Valiant" is a more user-friendly, less scientific version of programs developed in Ebert's lab that are intended for meteorologists and researchers to create accurate representations of quickly developing weather conditions.

"For instance, we made it so that you can alter details in a cloud, such as its dirtiness and puffiness and how dark the shadows are, whereas analogous controls in applications geared toward scientists might specify light scattering, attenuation coefficients and complex physics, which animators might not know," Ebert said. "We are assuming that most animators don't have a Ph.D. in atmospheric optics."

Ebert and Schpok wrote a research paper and presented findings about their work in 2003. Shortly afterward, they were contacted by Vanguard Animation, which was in the process of making the film and wanted to know whether the software might be used specifically to create three-dimensional clouds for the movie.

"I worked with one of the film's software developers and a computer-graphics supervisor to turn the software into a plug-in for a commercial animation package that they were using," Schpok said.

An added benefit of the software is that it can be used with recent PC graphics cards sold in computer stores and used to play video games in personal computers.

"It's impressive that clouds for movie-quality resolution were rendered using PC graphics hardware cards from NVIDIA Corp.," Ebert said. "Movie makers often use game-class graphics cards to interactively design and preview images, but they still go through a lengthy process of doing the high-quality, off-line movie rendering for each frame.

"The reason a graphics card is so much faster than the main processors in personal computers is because it has limited flexibility – it is designed to perform only certain types of graphics. But graphics cards for games are improving all the time so that you are getting better and better images while still being interactive.

"Joshua's software speeds up the process to about 10 frames per second for modeling and animation preview and about a minute for final images, instead of potentially hours per frame. He's gotten the process much faster so you can interact with the changing images in real time."

Purdue provided the movie producer with a free license to use the software specifically for "Valiant."

Ebert said he hoped that a license for Schpok's software might eventually be sold to additional film companies for use in other movies.

Research to develop the software has been funded by the National Science Foundation, the Purdue Research Foundation, a grant from Vanguard Animation and donations from NVIDIA and Alias Systems Corp., a computer animation software company.

Writer: Emil Venere, (765) 494-4709, venere@purdue.edu

Sources: Joshua Schpok, (765) 494-5943, schpokj@purdue.edu

David S. Ebert, (765) 494-9064, ebertd@purdue.edu

Purdue News Service: (765) 494-2096; purduenews@purdue.edu


Related Web sites:

Purdue University: https://www.purdue.edu

"Valiant": https://www.ultimatedisney.com/intheaters.html#val

This image, taken from the new animated film "Valiant," is an example of three-dimensional clouds created with the help of software developed by Joshua Schpok, a graduate student in Purdue's School of Electrical and Computer Engineering, and David Ebert, an associate professor of electrical and computer engineering. "Valiant" tells the story of a pigeon in Great Britain's Royal Homing Pigeon Service during World War II. Because the film's main characters are pigeons, many scenes take place in the sky and require clouds. Schpok adapted techniques pioneered by Ebert to tailor the cloud-animation software for the movie. The software enabled the film's producers to more quickly create animated images of clouds. (Image Courtesy of Vanguard Animation)

A publication-quality photo is available at https://www.purdue.edu/uns/images/+2005/schpok-animation.jpg


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