Hayley Iben: Science and math meet artistic expression

In February, the Academy of Motion Picture Arts and Sciences presented Scientific and Technical Awards to three women in a single season — a first for the organization, which also awards the Oscars. Since 1961, only 20 women have received the award, which honors the level of technical achievement based on overall impact to the film industry

Among those honorees was Berkeley Engineering alumnus Hayley Iben (M.S.’05, Ph.D.’07 CS), director of engineering at Pixar Animation Studios, for her work in developing Pixar’s Taz Hair Simulation System.

The Taz Hair Simulation System was first developed for the film “Brave” to create the massive red curls of its leading character, Merida. To mimic the thousands of interactions found in real hair, Iben’s team created a new model that captured the interactions within a single curly lock. The technique combines physics with a method that efficiently and stably computes the large number of interactions of locks with each other — particularly impressive with the signature volume of Merida’s naturally curly red hair.

Since “Brave” was released in 2012, nearly every Pixar film has used the technology. The system can be used to digitally create any type of hair style, from straight to wavy to curly. The team has since added new features to the same hair simulator to support hundreds of animated characters and a variety of iconic hair styles in Pixar films, including Helen’s swoop in “Incredibles 2”; Joy’s cowlick in “Inside Out”; the feathers and fur of Ducky and Bunny in “Toy Story 4”; and the blue ’dos of Ian and Barley in “Onward.” Their work on Taz has been patented and published as a conference paper and talks.

Pixar Director of Engineering Hayley Iben

For Iben, working in the film industry combines her childhood love of cartoons — especially hand-animated Disney movies — with her longstanding academic interests in computer graphics. As a graduate student at Berkeley, she completed her master’s thesis on morphing polygonal shapes and wrote her Ph.D. dissertation on the simulation of crack patterns on surfaces (think: drying mud).

“Hayley’s thesis work on simulating crack patterns was a nice example of using complex simulation algorithms to provide simple, yet powerful, tools for artistic expression,” said her doctoral adviser, electrical engineering and computer sciences professor James O’Brien. “This hair simulation project that she’s being recognized for is also an example of using simulation for building artistic tools, but the algorithms under the hood come from totally new ideas that she and her Pixar collaborators developed.”

Iben said that both degrees have contributed to different parts of her Pixar career. “The master’s was more relevant for my first position, where I was implementing inverse kinematics algorithms for character animation,” she said. And when an opening came up on the simulation team, her Ph.D. work prepared her for that new role, which is when she began working on the Taz Hair Simulation System.

After seven years on the simulation team, she was promoted to her current role as director of engineering, overseeing the teams who create and support technology spanning the production pipeline, including technology for the sets; the characters and crowds; the animation team; the simulation team, which creates the hair and cloth technology; effects; lighting and shading.

At any given time, Pixar has four to six films in various stages of production, each of which takes several years to produce; engineering teams like Iben’s support all of them simultaneously. They recently finished the technology for the upcoming “Luca,” which will be released this summer, and are actively working on “Turning Red” and “Lightyear,” due to be released in 2022.

When she’s not working on films, Iben does community outreach at schools as a founding member of Pixar Women in Technology, aiming to encourage students at all levels to consider computer science careers. At Berkeley, she was president of Women in Computer Science and Engineering, where she became acutely aware of the value of expanding engineering roles for women.

Because for Iben, a career as an engineer has brought tremendous fulfillment. Even after 14 years at Pixar and 16 film credits, she gets excited when she sees her credit roll by on the big screen when watching movies with her family and friends. “Brave” is still her favorite film and Merida her favorite character.

“It was such a struggle to get her hair right, and you’re so intimately connected to those characters,” she said. “So much new technology debuted in that film, including the award-winning Presto Animation System. It brought us all joy to complete that project.”

Maryann Simmons (M.S.’97, Ph.D.’01 CS) was also honored this year by the Academy of Motion Picture Arts and Sciences with a Scientific and Technical Award for her work on Walt Disney Animation Studios’ hair simulation system.