This fairy tale is large in scope, with songs by "The Book of Mormon" composer Robert Lopez and his wife, Kristen Anderson-Lopez, and a nordic setting of fiords and ice castles. The story follows a young girl named Anna (voiced by Kristen Bell) as she sets off on a journey to find her sister Elsa (Idina Menzel), who has trapped the kingdom in an endless winter. In April 2012, Buck enlisted Lee, who had joined Disney as a writer on "Wreck-It Ralph," to help shape the project.

One of the signature moves of the Lasseter and Catmull era at Disney has been the creation of the story trust, a group modeled on Pixar's so-called brain trust, where a dozen or so filmmakers gather to screen work for one another and consult on thorny problems of character, structure and tone. Attendees vary but typically include Lasseter, Moore, "Little Mermaid" directors Ron Clements and John Musker, "Tangled" directors Nathan Greno and Byron Howard and the studio's other directors.

During story meetings on "Wreck-It Ralph," Lee had distinguished herself as someone with a particularly rare mix of qualities — an assertive perspective as a writer but an ability to listen as well.

"We were all impressed by her voice in the story room," Lasseter said. "It's very important to have this real open, creative room for each movie, where the story team and directors and writers and everybody can discuss and be honest with each other. Her voice in this room was so strong on structure, character development, but very open too. We wanted that strong female voice."

Traditionally, the studio hadn't employed formal writers but let the story instead be shaped by animators — but contemporary movies have more complex storylines, with multiple plotlines and characters. "When you're writing in live action, you have more ownership," Lee said at the studio as she and Buck were in the final weeks of making story changes to "Frozen" last month. "In animation, you have to let the best idea win. You're constantly killing your darlings.

"What I like about doing a fairy tale today is, audiences want something big and meaty. It's not as simple as some of the classics like 'Cinderella.' It's not focusing on princess stories as much as family stories. It's one ordinary girl's struggle to help save the world, with her sister as the main obstacle."

Photos: Disney animates Marvel

When filmmakers are in the last year of production, they meet with Lasseter weekly — a change from the more insulated chief executives of earlier eras. (Lasseter still serves as chief creative officer at Pixar, consults on Disney's theme parks and occasionally directs his own movie, such as 2011's "Cars 2.")

"We used to have what we called the gates, or gatekeepers," said Buck, who left Disney in 2004 before returning in 2008. "There were all these executives who we had to show our work to before we got to the boss. Now you go straight to John, he gives you his gut reaction and you move on."

Life at the studio hasn't been all Disneyland smiles — last month, as part of a wider restructuring at its corporate parent, the animation studio laid off fewer than 10 people out of a staff of more than 800. Because some were 2-D animators, there was speculation on some animation blogs that the studio was abandoning its commitment to that art form, an idea Millstein dismissed.

"There's natural ebb and flow within an organization like ours," he said. "We have a deep cross-section of artists at our studio — hand-drawn artists, CG artists, software technologists who understand what's gone into our 2-D. We have deep, deep capabilities."

Competition in the animated features world has grown more intense, with more studios in the game — this year, in addition to films from Disney Animation's sister companies, the primarily direct-to-DVD unit DisneyToon Studios ("Planes") and Pixar ("Monsters University"), there are animated features from companies such as Blue Sky Studios ("Epic"), DreamWorks Animation ("The Croods," "Turbo"), Illumination Studios ("Despicable Me 2") and Sony Pictures Animation ("Cloudy With a Chance of Meatballs 2," "The Smurfs 2").

"The playing field for everybody is rising, and it's getting crowded," said Jerry Beck, a cartoon historian and editor of the website

Disney Animation's shorts program, which Lasseter and Catmull relaunched in 2007, has been part of a plan to build a deep bench of artists there. With budgets a fraction of Disney's features, the short films provide a lower-pressure venue for experimentation, both in technology and personnel.

When John Kahrs pitched his idea for "Paperman," a black-and-white, dialogue-less short that relies on both 2-D and 3-D animation, the movie had no obvious commercial value for the studio. But it became a vehicle to develop a new in-house drawing tool called Meander that integrates expressive, hand-drawn animation with CG animation. "Paperman" won an Oscar, Kahrs' producer, Kristina Reed, has gone on to be producer on "Big Hero 6," and Kahrs is working on a new film as well.

"Yeah, I don't know why they did that," Kahrs said of his executives backing the film. "I guess it had something cool and exciting in it, and it made you feel something."


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