In the 20 years since its release, “Toy Story” has been celebrated with an Academy Award, inspired Disney theme park attractions and landed a perch in the Smithsonian Institution. Leading man Buzz Lightyear even visited the International Space Station for a prolonged float-about.

All of those landmarks came center stage Monday night in San Francisco, where the creators of “Toy Story” and founders of Pixar Animation Studios took a rapt audience on a 90-minute “personal tour” of the film and the company that brought the world computer animation.

It has become almost a cliche to say that Pixar’s two-decade winning streak is owed to the company valuing creative story telling over mere technical wizardry. But the cliche rang true in front of a packed crowd at the Castro Theater, as company pioneers John Lasseter, Ed Catmull, Pete Docter and Andrew Stanton traded inside stories on everything from the naming of their original star (inspired by NASA astronaut Buzz Aldrin), to the thrilling storyboard session that turned plastic Army men from extras into featured players, to the desperate round-the-clock rebuilding of the movie that prevented Disney from pulling the plug.

“Toy Story” has secured its spot in history by being the first feature-length film made entirely via computer animation. But the entire presentation Monday emphasized that Pixar built its brain, from the start, to better power its heart. Catmull, the computer scientist who co-founded the studio and is now president of Pixar and Walt Disney Animation Studios, acknowledged as much with a story about his team’s reaction to the first critical response to “Toy Story” in 1995.

“Most reviews only had one line saying it was computer animation,” Catmull recalled near the end of Monday’s event. “And I have to tell you, all the technological people took incredible pride in that, because it wasn’t about the technology. It was about the story. And that’s been the foundation of the company ever since.”

Monday night’s event benefited the San Francisco Film Society, the non-profit that supports filmmakers, hosts educational programs and sponsors the San Francisco Film Festival each spring. It was the latest in a limited series of events celebrating “Toy Story.” A March panel at the South by Southwest Film Festival outlined the multiple iterations of story that led to the final product.

In August, Pixar announced another expansion of the “Toy Story” footprint, with the creation of a new 11-acre “Toy Story Land” at Disney’s Hollywood Studios in Florida. The film got another boost with a panel earlier this month at the Academy of Motion Picture Arts and Sciences in Los Angeles.

The company hopes to connect its next release, “The Good Dinosaur,” on Nov. 25, to the tradition. The film’s director, Peter Sohn, introduced a long clip of the film Monday that unveils Pixar’s newest buddies, the apatosaurus Arlo and the little boy Spot.

Chief Creative Officer Lasseter and Catmull took the audience briefly through their own personal odysseys at art school and in the sciences. Catmull then described his early days at Lucasfilm, where he led a group of 40 people that harnessed technology for filmmaking. Their breakthroughs have become the building blocks of the computer generated imagery that is now at the center of modern filmmaking: digital non-linear film editing, digital sound editing, high resolution editing and 3D computer animation.

Lasseter described days so long in the early Pixar era that he scarcely ever left the office — as evidenced by a photo showing him sleeping on a futon beside his desk. A breakthrough came in 1986 with his creation of the animated short, “Luxo Junior,” that portrayed a parent and baby desk lamp, playing with a rubber ball. Another young creative named Steve Jobs saw the short at a technology conference in Dallas. “I was blown away when I saw Luxo,” Jobs said, in a video played for the San Francisco crowd. “Luxo was a big turning point for me. … You saw Luxo and said ‘Yes, I could watch and hour of this. I would love to watch an hour of this.'”

The Apple Computer founder went on to buy Pixar and to become a steadfast partner for Catmull and Lasseter. The two men remember the late Jobs in far different light that the martinet of recent biography and film. They recall Jobs telling them earnestly: “No matter what happens, we have to trust each other.”

What would later become “Toy Story” actually grew out of a project to make a half-hour holiday special, spun off from the Academy Award-winning short film, “Tin Toy.” The character that would become toy cowboy Woody started as a ventriloquist’s dummy. The project fizzled. But when Pixar signed a distribution deal with Disney, the young company suddenly needed ideas for feature films and it turned back to the ventriloquist’s dummy concept. Lasseter explained that the string puppets were quickly deemed “too creepy.” Super-creator and animator Docter soon joined Lasseter, writer/creator Andrew Stanton and artist/animator Joe Ranft in brainstorming how to improve the concept. They came up with a “karate-chop action” figure that would morph into Buzz Lightyear.

The team conceived as a “buddy picture,” featuring mismatched pals. They studied prototypes as obvious as “The Odd Couple” and as unlikely as “The Defiant Ones.” Together, the heroes had to forge their alliance in adversity, Lasseter believed. “We started thinking about we could do to an old toy that is a child’s favorite and the child gets a new toy on his birthday, which has got to be the most feared day in an old toy’s life … besides Christmas,” Lasseter said.

The filmmakers faced their own creative mortality, following a directive from Disney that the early drafts of “Toy Story” were too soft. They were told “edgy. Be more edgy.” But they pushed the character of Woody to the point that he became downright nasty — abundantly demonstrated in a sketch sequence played for Monday’s audience. The result, Lasseter declared flatly, “was horrible.”

“But beautiful, in a way,” quipped Stanton. Disney executives told the Pixar team they didn’t think the studio could support the film. The day of the disastrous presentation to Disney became known around Pixar as “Black Friday.” But creative master Lasseter begged Disney for two weeks. “I said give us two weeks and if you don’t like what you see, we will move down [to Los Angeles] and shut production down,” Lasseter said.

That led to a frenetic, all-hours rewriting of the film. “We completely redid the movie,” Lasseter said. In the process, the young company learned a lesson: “We took the notes that we think make the movie better and throw the ones away we think don’t. And start trusting our own instincts at that point.” Two weeks later, Disney was “stunned” by the film’s turnaround. A homemade video shows the creative team receiving the good news from Disney executives, including Bonnie Arnold, that “Toy Story” again had a green light.

Stanton said that, from their early days, the Pixar team determined to hold on to its own prerogatives. They loved the Disney animated films of the past, but wanted to make their own rules. And those included (only slightly tongue in cheek) “no songs, no happy village … no villains.” The rules would be bent, but the creative process would remain intact, the Pixar team said.

The Pixar brain trust did not have to review the ensuing record for the San Francisco gathering, as many in attendance already knew it. The sequel “Toy Story 3” (2010) easily outstripped the original in box office dollars — bagging more than $1 billion worldwide, compared to $362 million for the original. A solid hit like “Toy Story 2” (1999) registers as merely passable by the studio’s lofty standards, though most filmmakers would kill for its $485 million take.

This summer, the company hit again, with another concept that cut against conventional wisdom. “Inside Out” adopted the almost revolutionary conceit, for a “children’s” film, that embracing sadness is an essential facet of human happiness. That decision paid off not only in more critical acclaim but in another box office bonanza. Since its June opening, bittersweet “Inside Out” has taken in more than $842 million worldwide.