Last month in the US, Pixar Animation Studios debuted their latest release, Toy Story 3, to the tune of $110m (£72m) and glowing reviews from all corners of the media. It's a familiar refrain for the company. In 15 years of making movies, they've never had a flop. Their competitors have tried and failed to come close to their level of critical acclaim. And while the law of diminishing returns affects most sequels, Pixar's Toy Story follow-ups have only heightened the experience of the original. What is it about the Emeryville, California-based company that has allowed this unparalleled run of success?

With its grand atrium basking in Californian sun and decorated with giant canvases of colourful concept art, Pixar's HQ – across the bay from San Francisco – feels less corporate office block, more Church of Animation. Its congregation, some 1,200 strong, gathers every breakfast and lunchtime, and then disperses back to offices around the building to get to work.

According to Pixar's co-founder and chief creative officer, John Lasseter, herding its staff into this central area for mealtimes inspires the departmental interaction necessary to keep the quality coming. As artists mix with model makers and animators meet engineers, everyone involved can appreciate the role of their particular cog in the larger machine, and the wider value of even the smallest contribution.

But architecture alone doesn't explain the company's unblemished record of 11 critical and commercial hits, he explains. "Pixar is a studio of innovators. It's a culture in which everyone is addicted to the idea of breaking new ground. They live for that. [And] every single animator that has been brought in from the very beginning believes in making great stories."

Ask any Pixar employee and they'll refute the suggestion that they can't make bad films. "We make bad films all the time," counters Bobby Podesta, one of Toy Story 3's supervising animators, who has been at Pixar since 1997. "Almost every film of ours has been a horrible film at some point, but we're very good about being honest with each other and saying, 'This is horrible. Here are some ways to make it better'."

The company's brutal self-review process demands that thin-skinned animators need not apply, says fellow supervising animator Mike Venturini. "Through the interview process, we'll decide if [prospective employees] are fit for the rigours of working at Pixar. But it takes time for animators that have worked at other studios to let their guard down and understand that when they're given feedback it's done in a non-judgmental, supportive way."

And Pixar is clearly unafraid of making tough decisions during that process. Animator Jan Pinkava joined the company during pre-production on the first Toy Story, and was to have made his directorial debut with 2007's Ratatouille, an idea he'd germinated at the studio seven years earlier. But just 18 months shy of the film's release, he was replaced by the director Brad Bird.

Similarly, rumours abound that story issues have prompted Lasseter to take a more active role in the development of Pixar's 2011 release, Cars 2. The project currently belongs to the first-time director Brad Lewis – who produced Ratatouille – but internet reports suggest that Lasseter will take a co-director credit and help with the last year of production. Disney denies any such decision has been made.

Keeping a firm hand at the rudder is key, says WALL-E's producer Jim Morris, who joined Pixar during Ratatouille's development. "Unlike other environments with this melting-pot of collaboration, [here] the director is always the final word. We rely on the director to deliver. In Pixar's history there've been some times when it hasn't [worked out], and we've had to make changes, but the preponderance of times it's paid off makes it worthwhile."

Pinkava left Pixar after losing the reins on Ratatouille, and has been reticent in discussing the circumstances of his departure. But with the film's box-office receipts in excess of $500m worldwide, and a best animated feature Oscar in the bag, it's hard to argue with the decision to replace him. Creative culture and canny architecture aside, it seems faith in making these big decisions is what has ensured such an unbeaten run for Pixar.

As the company closes the door on its most lucrative franchise and looks to the next 15 years of existence, its ability to sustain that run of form seems pretty comfortable. In Emeryville, the happy congregation's prayers to the gods of animation are clearly being answered.