With its back to a wall, the Walt Disney Company shelled out $7.6 billion in 2006 to buy Pixar, the animation powerhouse behind “Toy Story” and “Finding Nemo.”

This weekend, the smashing success of “Zootopia” confirmed the wisdom of that decade-old acquisition. It continues a string of box office hits such as “Tangled,” “Big Hero 6,” “Wreck-It Ralph” and “Frozen” that might not have been possible had Disney not absorbed Pixar and its brain trust.

Although they were released under the Walt Disney Animation Studios banner, Pixar’s DNA — a double helix of artistic daring and technological innovation — is evident in all of these films. That makes sense given that as part of the Pixar purchase, the company’s leaders Ed Catmull and John Lasseter assumed responsibility for all of Disney’s animated output.

“What they have focused on in each of these films is having an original voice and an original story, all set in an original world,” said Dave Hollis, Disney’s distribution chief, who dubbed Walt Disney Animation Studios a “momentum machine.”

It wasn’t always clear that the bet would pay off. Some on Wall Street questioned whether Pixar was worth the astronomical purchase price, but the fact remained that the house that Mickey Mouse built was in need of some renovation, and Disney didn’t have much choice other than to pony up. It had surrendered its dominant position in the animation market to a gang of computer wizards who had an uncanny ability to create a new generation of animation icons. From Buzz Lightyear to Mr. Incredible, the Pixar heroes were every bit the equal of Peter Pan, Cinderella, Simba and other staples of Disney’s family friendly empire.

In the process, Pixar had supplanted Disney’s feature animation arm. As Pixar thrived, Walt Disney Animation Studios spent the late ’90s and early aughts mired in a creative and commercial torpor. “Home on the Range,” “Atlantis: The Lost Empire,” “Treasure Planet” and “Brother Bear” failed to stir the imagination, floundering at the box office and making the glory days of “The Lion King” and “Beauty and the Beast” seem very long ago indeed.

“It was the bottom of the barrel,” remembers Jeff Bock, a box office analyst with Exhibitor Relations.

To fix the animation unit, Catmull and Lasseter essentially remade it in Pixar’s own image. It took Pixar innovations — namely an emphasis on story and a workshop approach to working through the problems and thorny elements of a film — and exported them to Walt Disney Animation Studios. As part of the Pixar-ization, Catmull and Lasseter instituted an open office plan, recruited new talent and emphasized jettisoning the generic.

“They’ve surrounded storytellers with other storytellers and that’s created an environment where collectively they can focus on delivering something great,” said Hollis. “They’ve empowered storytellers.”

In the process, Walt Disney Animation has become perhaps the most original voice in the animated world. At times it has worked from well known source material. “Frozen” was inspired by Hans Christian Andersen’s fairy tale “The Snow Queen” and “Big Hero 6” was based on a comic-book, but the studio’s artists have embraced myriad genres and approaches while crafting each of their movies in ways that make them feel unique.

“Frozen” embraces the showmanship and emotionalism of the Broadway musical, “Big Hero 6” integrates visual elements of Japanese anime and “Wreck-It Ralph” serves up a heartfelt ode to arcade games. “Zootopia,” which opened to a record-breaking $73.7 million this weekend, is no different. The story of a rabbit trying to break into the police force plays like a buddy cop comedy with cuter squad car inhabitants. It has also been embraced by critics for bucking convention, with the New York Post’s Lou Lumenick calling it the year’s best film so far

and Variety‘s Peter DeBruge calling it “an adult-friendly whodunit with a chipper ‘you can do it!’ message for the cubs.”

The Disney animation rebound has taken place as the family film business has grown crowded. For a time, the animation sector was carved up between Disney/Pixar and DreamWorks Animation, but over the past decade, many new players have entered the marketplace. Fox’s Blue Sky and Universal’s Illumination have all fielded breakout hits such as “Ice Age” and “Despicable Me,” while Warner Bros., Paramount and Sony are investing heavily in their animation divisions. The margin for error has never been slimmer.

“It is a far, far more competitive landscape now than it was three, four, five, six years ago,” DreamWorks Animation chief Jeffrey Katzenberg said this week at the Morgan Stanley Technology, Media & Telecom Conference.

He noted that in the old days, a company’s name above the title was enough to guarantee a certain level of financial performance. That’s no longer the case, he added.

“It was the brand that did the work for us,” said Katzenberg. “We can’t rely on that anymore.”

Ironically, Disney Animation’s revival has occurred at a time when Pixar has seemed less sure-footed. Though “Inside Out,” an imaginative look at the emotional landscape of a pre-teen girl, was one of the studio’s most beloved and acclaimed productions, it has been the exception and not the rule, of late. Pixar stumbled badly with “The Good Dinosaur,” its first financial flop, and has been increasingly focused on churning out sequels to past successes such as “Monsters University” and “Cars 2.” They have been financially successful, but lack the shock of fresh that characterized earlier Pixar efforts. This summer brings “Finding Dory,” a follow-up to “Finding Nemo,” and new installments in “The Incredibles,” “Cars” and “Toy Story” franchises are also on the horizon.

“Pixar used to be all about originality,” said Bock. “But they fell into sequel mode as most studios do and now it’s Disney Animation that is the one trying new things.”

At some point, Bock says, the studio will get sucked into making sequels to “Tangled” and “Frozen,” but until that time, it’s Walt Disney Animation Studios and not Pixar, that is extending the boundaries of what is possible in animation.