How to Bottle a Waterfall

by Neil Caudle


You can lead a robot to water, but…

This frame from the short film “Roboasis,” created by students in DPA 8600, shows a robot approaching the waterfall, divining rod in hand. The seven-second film includes 86,971 frames and required eleven terabytes of data. That’s eleven trillion bytes. See a web-friendly version of the short film.

What’s the cost of a second of film time?

If you have to ask, you can’t afford it.

Seven seconds. Not long, in a film. But if you’re one of the few brave souls chosen to toil in a lab while the laundry piles up and your friends assume you’ve been abducted, you’ll learn the real value of a second. A second is worth three hundred hours of mind-bending work.

At least that’s the going rate if you’re a student of Jerry Tessendorf, whose work in digital animation has established him as a pioneer in the field. Tessendorf contributed to Life of Pi, which won an Oscar for visual effects. He knows from experience that a single storm-tossed wave demands a hurricane of work.

“Students have other classes, so I can’t ask them for more than about twenty hours a week,” Tessendorf says. “I think all of them are doing at least double that right now—at least.”

Tessendorf is talking about a fall 2013 project his students called “Roboasis,” a seven-second scene from a story. Here’s the concept: Our intrepid robot has been deployed to explore a new world and find water. Equipped with a bottle and an old-fashioned divining rod, he trundles forth and finds a lush oasis, complete with thundering waterfall. So he ditches the divining rod and readies his water bottle. But uh-oh, there’s a tricky little problem of how to bottle a waterfall. Things don’t go according to plan.

The clip is comical, human, and visually rich—everything today’s audience has come to expect. It’s no accident that the production happened at Clemson. With Tessendorf and several other standouts in the field, the Department of Digital Production Arts has established itself as a national leader (see Making Magic). And industry has been taking notice.

Last summer, DreamWorks Animation came to campus for a hands-on summer workshop with selected Clemson students. With guidance from DreamWorks mentors, ten students divided into two teams, and each team created a fifteen-second animated film.

“The intent was that the students would produce films that are professional quality,” Tessendorf says. “That’s one reason the films are so short. The quality had to be professional, and it was.”

DreamWorks dispatched two of its supervisors to Clemson for two weeks, and for the entire ten-week workshop DreamWorks mentors reviewed the work remotely, a common practice in the industry, Tessendorf says. Twice a week for ten weeks, students uploaded their works in progress and used software to synchronize frame-by-frame what they and their mentors saw on the screen.


Along with Jerry Tessendorf, Timothy Davis and David Donar supervised the project.

Students included Alex Beaty, John Barry, Brianne Campbell, Liam Glover, Kara Gundersen, Gowthaman Llango, Marie Jarrell, Hugh Kinsey III, Virginia Nearing, and Sarah Runge.

The full treatment

This was a workshop with an emphasis on work. The day officially began at eight a.m. and ended at ten p.m. Welcome to the real world of digital animation, notorious for its punishing schedules. But pushing past the point of bleary-eyed exhaustion often yields an in-the-zone creative outburst absent in a nine-to-five office job, Tessendorf says.

“So the students got that part of the experience,” he says. “A few weeks into the workshop they hit this wall you have to pass, and you’re so exhausted that you focus on your work and get very productive, because you can focus so tightly, and any distraction away from that work is annoying, and you just don’t want to do it. You could actually see that happening with the students. On July Fourth, we had an official day off. Half of them did stay home to do their laundry, apparently. The other half came into the lab anyway, because it’s just an annoyance not to be in there doing that work.”

But students dare not geek themselves into joyless drones. They have to know what it’s like to be human, to laugh and love and cry, because the heart of any good film is a story. So the challenge, as Tessendorf sees it, is both technical and artistic.

Much of what the students actually do in the lab is, at its root, difficult math brought to life. Tessendorf, for example, developed a mathematical model useful for rendering water—and there’s an ocean of it in Life of Pi. For decades, the industry has been incorporating such advances into software code, helping animators do their jobs. Tessendorf’s students use the software, but they also pop the hood and get their heads around the math.

So there’s math and hard work behind the cinematic dream, and people who study the trade quickly abandon the notion that digital animation is fake, because you just can’t fake the good stuff. You have to feel it and you have to earn it, step by step.

In their simplest outline, the steps go something like this, Tessendorf says: You start with a concept, an idea, and build a model in wireframe—a grid-like shape composed of lines. Then you add texturing, which makes the model look like wood or plastic or whatever you need. Texturing requires artistry to make the surface look natural, with, say wrinkles, or the dents and dings of wear and tear. Today, animators call this surfacing, and the best ones make the likeness seem uncanny.

Putting it all in motion

But no matter how apt the structure and surface, films are first and foremost motion pictures. Objects and characters have to move; waterfalls have to plunge with wild abandon. “There’s a process called rigging,” Tessendorf explains. “You can think of it as adding controls to the model so that you can animate it, and a lot of times that’s represented graphically as if there’s a skeleton in the model. Different parts of the skeleton affect different parts of the model, so when you move the skeleton, those parts of the model move with it. That’s actually a very complex, mathematically intensive process.”

This kind of intensity requires high-powered computing. The rapid expansion of computing speed and capacity over the last decade has made it possible for animators to plant hundreds or even thousands of control points in their rigging, instead of the handful they once used. This means a much wider range of smooth, natural motion, Tessendorf says.

So it takes all of these steps—modeling, surfacing, and rigging—to reach the stage called animation. A big part of this final stage is lighting: Carefully simulated light sources yield natural-looking shadows and highlights that track with movements and changing environment. “That’s when we add all of the nuanced animations,” Tessendorf says. “You put together all the parts and characters into what you want the scene to look like.”

To sample the finished product, I found a seat in a darkened screening room to watch the two fifteen-second films his students built—a word Tessendorf uses because there’s so much construction involved—with guidance from DreamWorks. Each film featured an irresistibly klutzy little robot that bumbles its way toward disaster. And each made me laugh out loud. Somehow, the students had rendered, in pixels, authentic-looking characters moving in natural ways through richly detailed little scenes. They had also rendered a story, a comic and convincing glimpse of our own unruly humanity.

Jerry Tessendorf is a professor in the Digital Production Arts Program, School of Computing, College of Engineering and Science.

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