HBO/Hisko Hulsing/"Kurt Cobain: Montage of Heck"
But there's one particular piece in the documentary, directed by Brett Morgen ("The Kid Stays in the Picture") that no one, not even Cobain's family or closest friends, ever knew existed.
Morgen had been working on the project for five years when he finally got the call. In 2013, he was granted access to a storage space where Cobain's most intimate materials - journals he wrote and paintings he created - are kept.
"One of the things that would change the direction of the film was a box that I found that said, 'cassettes,'" Morgen told Business Insider.
HBO/"Kurt Cobain: Montage of Heck"
Hidden among the hours of recordings of Cobain playing music and joking around, he came across a story Cobain taped in 1988.
"I knew instantly it was different because he was performing it and was doing multiple takes on it," Morgen explained. "It was a little more narrative than most of Kurt's art."
The story Cobain tells in the recording is of his first sexual encounter, which then leads to the first time he contemplated suicide.
Morgen brought the recording to the Cobain family, who had never heard it. He even brought it to the attention of Cobain's biographer, Charles R. Cross, who wasn't aware of its existence, either.
Morgen knew it needed to be in the film, but how could he make it work visually for the movie?
Morgen is famously known for using animation in his work. In "The Kid Stays in the Picture," he used effects to bring still photography to life in his story of Hollywood mogul Robert Evans.
YouTube/USA Films/"The Kid Stays In The Picture"
And the 2007 film, "Chicago 10" - a look at the anti-war protestors put on trial following the 1968 Democratic National Convention - is entirely animated.
But Morgen admits he initially had no intention of animating the Cobain audio.
"We were going to animate his art and his journals (made for the film by artist Stefan Nadelman), but there was never a discussion about animating Kurt," he said.
But then he came across the work of Dutch artist/filmmaker Hisko Hulsing and his animated film, "Junkyard."
"I felt that he had a similar dystopian view of the world that Kurt had, but a much better craftsman than Kurt," said Morgen of Hulsing. "But the view and the tone had a lot of similarities, a lot of darkness and twisted reality."
Hisko Hulsing/"Junkyard"
"I've never been a Nirvana fan," Hulsing admits. "I think I was 21 when 'Smells Like Teen Spirit' became a hit and I just had a dark, psychotic adolescence, so it didn't strike a right cord for me."
But Hulsing said he agreed to come on because he was fascinated by Morgen's mission to celebrate Cobain's life, not mythologize his death.
Wendy O'Connor/HBO
From his small studio in Amsterdam, Hulsing compiled a team of 27 people (18 of them animators) and for four months they worked on not only the Cobain audio story, but the other portion of the film Hulsing was responsible for. For the 85 shots that were Hulsing's responsibility, they produced 6,000 animations and 60 oil paintings on canvas. Some of those canvas paintings were as large as six feet.
Hulsing would then take a digital picture of the canvas, input the animation that would go in front of it, and send to Morgen back in L.A. for approval.
Here's an animated rendition of Cobain as a teenager.
HBO/Hisko Hulsing/"Kurt Cobain: Montage of Heck"
Hisko Hulsing/HBO/"Kurt Cobain: Montage of Heck"
HBO/Hisko Hulsing/"Kurt Cobain: Montage of Heck"
HBO/Hisko Hulsing/"Kurt Cobain: Montage of Heck"
And during that month happened to be the epitome of my mental abuse from my mother. It turned out that pot didn't help me escape my troubles too well anymore, and I was actually enjoying doing rebellious things like stealing booze and busting store windows.
HBO/Hisko Hulsing/"Kurt Cobain: Montage of Heck"
HBO/Hisko Hulsing/"Kurt Cobain: Montage of Heck"
HBO/Hisko Hulsing/"Kurt Cobain: Montage of Heck"
I got grossed out very heavily with her smell and her sweat reeked, so I left. My conscious grew to where I couldn't go to school for a week and when I did I got in-house suspension for skipping.
HBO/Hisko Hulsing/"Kurt Cobain: Montage of Heck"
HBO/Hisko Hulsing/"Kurt Cobain: Montage of Heck"
HBO/Hisko Hulsing/"Kurt Cobain: Montage of Heck"
HBO/Hisko Hulsing/"Kurt Cobain: Montage of Heck"
Hulsing said the bleak look he gave the animation came from what he observed looking at photos of Aberdeen, Washington, where Cobain grew up.
"Images and videos of Aberdeen clearly show that it's often grey and rainy," Hulsing said. "I believe that the somber palette adds a lot of darkness and hopelessness to the story of young, suicidal Kurt."
Hisko Hulsing/HBO/"Kurt Cobain: Montage of Heck"
HBO/Hisko Hulsing/"Kurt Cobain: Montage of Heck"
The music played over the telling of the story is a string arrangement of the Nirvana hit, "Smells Like Teen Spirit," arranged by composer Jeff Danna. "There was already some existing music of strings playing 'Smells Like Teen Spirit,'" Hulsing said. "So [Morgen] put that under my moving storyboards in the beginning and it really worked for Brett, so later he had a new composition done."
The End of Music LLC/HBO
"Once we saw the final assembly edit, Joe Beshenkovsky, who edited the film with me, both of us felt we were pretty comfortable where we landed," said Morgen. "But at the same time we knew Hisko was just getting started [on animating]. There was this fear, 'Hisko is going to be our Achilles heel if he doesn't deliver.' It's not like we could cut out the sequence. I've had some treacherous experiences with animation not really working out the way you'd hoped."
But when Hulsing delivered the first drawings, all the anxiety rushed away.
"He gave me a gift," Morgen said. "He was really committed to the work. He really wanted to get it right and I really appreciate that about him."
Hulsing said with a chuckle about the experience, "I'm still recovering."
Jaroslav Repta
"I met Krist Novoselic, the bass player for Nirvana, at Sundance and he said that he knew Kurt very well from a young age and he never heard that story before," said Hulsing.
Morgen and Cobain's wife, Courtney Love, also questioned the story's veracity at a Q&A following the film's screening at the Tribeca Film Festival last month.
But, Morgen told BI, whether it's real or not doesn't interest him.
"I'm not a writer or a historian," he said. "I'm making a movie and it's a depiction of his art, so I'm out for an emotional truth."