Claudia Chung joined Pixar in 2003 to work on FINDING NEMO. She then worked on THE INCREDIBLES, RATATOUILLE and UP. In the following interview, Claudia talks about the many challenges on BRAVE and especially the hair.

What is your background?
I have a Computer Science degree from University of California Berkeley. I came to Pixar as a Render TD, transitioned to Simulation on THE INCREDIBLES. On RATATOUILLE, I started tailoring and taking on more artistic aspects of Simulation. Initially I was terrible at tailoring so my lead at the time put me in a sewing class. I was Cloth Lead on Up and finally Simulation Supervisor on BRAVE.

How did you collaborates with the directors?
As the supervisor, I’m constantly working with the directors, art and animation departments to figure out what the creative hope and direction is. I can then translate this to the team and work with individual artists in hitting the goals of the director. When a story element is introduced to the film before the shots enter our department, for example Merida falling into the river, we’ll work with the director to understand his vision of what Merida looks like wet and how her hair and clothes should behave. We have 2-3 reviews with the director every week, showing models or shot work.

Merida hair are just amazing. Can you explain to us in detail how did you create these?
The groomer, Lena Petrovic, and the art director, Steve Pilcher, worked closely together to give Merida’s hair the personality it has. As Lena was grooming, she realized she needed a faster way to create curls. Thinking how she would do this in real life, Lena created essentially a curling iron in the computer so she could quickly create uniform curls. That would leave time for the more important aspect of hand sculpting these uniform curls to what Art and the director wanted.

How did you manage so many hairs and curls?
A new simulator, called Taz, was created. Taz was powerful in two key ways. It could handle hair-to-hair collisions in an intelligent, multi-threaded way. This gave Merida’s hair the volume that’s characteristic of curly hair. The second feature was it’s ability to solve the paradox of curly hair. Curly hair is stiff in the way that it never loses the curl or spiral, but yet in overall movement, it’s actually quite soft and light. Taz computed essentially two curves per hair curl, one that represented the curls and another that represented the overall wave and movement along the length of the curl.

How long did you work on the R&D for this hair system?
It took 3 years, from start to the day we declared we were successful in finally hitting the look of Merida’s hair. Many many smart minds contributed to the final result. To be clear, it wasn’t just the look and movement that took so long, but stability was a huge part of its success as well. We had to make sure the simulator could actually finish the film without artists having to constantly clean up and hand-tweak results. In the end, Merida’s hair was one of the easiest models we had to simulate.

Merida and her mother wears various long dress. Can you explain to us step by step their creation?
At Pixar, we model all our costumes in 3D. We model them as quads and then in the « sewing » process the meshes are tessellated into triangle meshes which are better suited for simulation. During this sewing process, we create the gathers and seams that you see in Merida’s dress. The mesh is then « relaxed » or fitted onto the character who is standing in an awkward neutral pose. It’s an iterative process until the garments fit the character whether she’s just standing there or animated. It mimics what you would do in real life. All of our dresses can be flattened into a pattern that could be conceivably printed out and sewn together in real life. This is important because this pattern is the foundation that gives the costumes the realistic motion and dynamics that our human eyes are sensitive to.

What was the biggest challenge on this project and how did you achieve it?
There were so many challenges. The biggest were Merida’s Hair, Angus’s groom (8 separate types of fur that each had to have unique dynamics, yet look graphically appealing) and Fergus’s costume (8 layers of cloth and the kilt itself is layered 8 times). Any of these challenges required a lot of patience and research.

Was there a shot or a sequence that prevented you from sleep?
Not really. I was lucky to have an amazing team of tailors, groomers, and simulation artists. They were always eager and willing to take on more and more challenges and convince me that anything thrown at them was possible. Whether they lost sleep over what they agreed to, however, you’d have to ask them.

What do you keep from this experience?
So many things. The top is how amazing the people I had the pleasure of working with here at Pixar were — from the directors to the individual artists on the team. These are the people who inspired me to come into work everyday. From a simulation point of view, I’m excited to see our very technical discipline carry into the artistic and creative realm. Discussions were no longer about what is technically possible but about communicating what is artistically sought after. It really rewards both sides of the brain.

What are the four movies that gave you the passion for cinema?

A big thanks for your time.


Pixar: Dedicated page about BRAVE on Pixar website.

© Vincent Frei – The Art of VFX – 2012


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