Fear, anger, disgust, sadness and joy have taken over Pixar headquarters, and things are going great.

The Oscar-winning animation studio is celebrating the completion of “Inside Out,” a film that features each of those emotions as personified characters controlling operations inside a little girl’s head.

Sculptures, sketches, paintings and other concept art from the film 5½ years in the making fills a gallery at the studio’s resort-like headquarters in northern California. Some 350 artists and technicians collaborated under the direction of Pete Docter (“Up,” “Monsters, Inc.”) to bring the imaginative adventure to life.

“Inside Out” tells a story of two worlds — the external, human world and the internal landscape of the mind — and how they influence one another. As 11-year-old Riley navigates the human world, including a move from her native Minnesota to San Francisco, her mind’s staff of emotions handle her internal goings-on.

Joy (Amy Poehler) was the de facto leader of the emotion team, but when she and Sadness (Phyllis Smith) get lost deep in the recesses of Riley’s subconscious, Fear (Bill Hader), Anger (Lewis Black) and Disgust (Mindy Kaling) are left in charge. Joy and Sadness, with the help of a character named Bing Bong, must bridge their differences to ensure Riley’s happiness and the ongoing development of her personality — heady territory for an animated, family film.

With the project recently completed, Docter and producer Jonas Rivera invited reporters to Pixar to explain why “Inside Out” was so time-consuming.

Animated movies typically take longer than live action to produce because everything has to be built — not only the sets and costumes but the characters and cameras.

On this film, though, the artists had to create entire worlds.

“Inside Out” started with an idea from Docter, inspired by his daughter who’d gone from an outgoing, happy kid to a quiet, sullen pre-teen. He imagined a story set inside a little girl’s mind that explored what went on in there.

His team met with neuroscientists and psychologists to learn some basics about emotion, memory and mind function.

Then it was up to the story artists to develop characters based on that information, conceptualize how they should look and act, and come up with a script. Meanwhile, production designer Ralph Eggleston was dreaming up what the world of mind and personality might look like.

“It was an intellectual idea we had to conceptualize,” he said. “The biggest challenge was what is the mind?”

Filming comes next, before animation, inverting the familiar lights-camera-action formula.

“In animation, it’s camera, action, lights,” said director of photography Patrick Lin.

Animators — a team of 45 in the case of “Inside Out” — give expression and personality to the characters. It takes about a week to produce 3 seconds of animation, said directing animator Jamie Roe.

Lighting comes last, and it functions like a cinematographer would on a live-action film, shaping the shot and directing the eye, said lighting artist Angela Reisch. Like animation, lighting each scene is a painstaking process, and artists can complete only a few shots a week.

The film is set for release June 19.