Mist, fog and dark clouds, set against lush backgrounds was a production challenge throughout.  All images ©2012 Disney/Pixar. All Rights Reserved.

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Yes, Brave is Pixar's first "chick flick": a mother-daughter test of wills set in medieval Scotland. Inspired by Brenda Chapman's own tempestuous relationship with her teenage daughter, she wanted to turn the princess story on its head with a dose of modern reality. They just happen to be royalty, which raises the stakes with an entire kingdom in the balance. But it's certainly fun watching Queen Elinor (voiced by Emma Thompson) and Princess Merida (voiced by Kelly MacDonald) butt heads. And then the story gets very Grimm with a magical twist. It's a bit like Freaky Friday only darker and much more ambitious.

Alas, Chapman butted heads with the Pixar brain trust after six-and-a-half years and was replaced by Mark Andrews, though she still retains director credit. For his part, Andrews credits Chapman with providing a great mother-daughter relationship, but suggests she couldn't see the forest through the trees, so he pared it down. Even Chapman agrees her story was way too complicated. But what an achievement: Pixar delves more deeply into human relations while creating a lush, organic world.

For Brave, Pixar overhauled its animation program, creating Presto (named in honor of the 2008 short). This allowed a lot more flexibility for previewing during animation and they could write tools right into it, such as the advanced simulation for Merida's hair, which was the most daunting task of all. Back on Monsters, Inc., they wanted Boo to have curly hair but it just wasn't possible to achieve the necessary hair to hair collision. But with Merida, technology caught up with need, with her wild, unkempt orange hair being such a vital part of her fiery personality.

The most daunting task of all was perfecting the advanced simulation used on Merida's hair.

"The basic model is the same for the hair but we realized two key things," explains simulation supervisor Claudia Chung. "Hair to hair collision is really slow, so in order to do that the engineers that created our simulator parallelized everything. They split the simulation into eight processors. Then we painted her and we don't see the color until the very end."

Speaking of hair, Merida's faithful Clydesdale, Angus, is arguably the best CG horse ever animated. The musculature is so believable and the hair flows just right. Credit goes to Presto once again as well as the simulation team. "The challenge with Angus was simulating so many layers and making sure his mane flows smoothly through the wind," Chung continues. "Unlike Merida, where her hair sims all at once, Angus' pieces sim separately because they all have to interact at the same time. Hers take eight cores to simulate and his takes 64 because of his eight layers. Also, Merida is the same setting out of the box, whereas Angus has different settings for mane and other clumps."

Angus, is arguably the best CG horse ever animated.