Film TED-Ed

# The math behind the movies: An interview with Tony DeRose of Pixar

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Tony DeRose captivated the young audience at TEDYouth, talking about how mathematics makes Pixar characters look so real. Photo: Ryan Lash

Pixar films are known for their thoughtful storytelling and groundbreaking animation. One of the coolest things about these movies: the math that Pixar’s team is actually inventing to improve the audience experience and the look of the characters. We caught up with Pixar’s Research Lead, Tony DeRose—who gave the TED-Ed Lesson, “The math behind the movies,” about how arithmetic, trigonometry and geometry helped bring Woody and the rest of your favorite characters to life—to hear more. Bonus: we got to hear about his own progression from building model rockets to creating Oscar-winning characters.

What got you interested in mathematics as a kid?

I can’t remember a time when I wasn’t interested in science, but my interest in mathematics really began when I was in 7th grade. I was into building model rockets, and my 7th grade science teacher, Mr. Belknap, showed me how to use trigonometry to calculate how high the rockets went. I thought it was magical that such a thing could be done by scratching equations on paper. I’ve been hooked ever since.

How did you end up at Pixar?

Before joining Pixar, I was a professor at the University of Washington teaching computer science and doing research in computer graphics. There were only a few people doing computer graphics at that time, so everybody knew everybody. Ed Catmull, the president of Pixar, was part of that community, so we stayed in touch from time to time. As Toy Story was being completed, Ed and I started talking about the possibility of me moving to Pixar. The opportunity to help develop the technology needed to tell compelling stories using computer graphics was too good to pass up, so I did the unthinkable and left a tenured position at UW. My parents thought I was crazy, by the way, but they trusted my decision.

Who is your favorite animated character that you have personally worked on?

Geri from the short film Geri’s Game. He was the first character I worked on, and he won an Oscar. He also made a cameo appearance in Toy Story 2 as the toy cleaner.

What advice would you give someone who wanted to use math to make movies?

Learn as much mathematics as you can, particularly applied math. The areas of mathematics we use most heavily today are Euclidean and affine geometry, trigonometry, linear algebra, calculus and numerical analysis. We don’t really know what the mathematical tools of tomorrow might be, so we’re counting on the next generation of employees to tell us.