When the documentary filmmaker Brett Morgen hit his eighth month of writer’s block on an epic project about David Bowie, he decided it was time to hit the road. With just a few hours’ notice, he left his home in Los Angeles one morning and grabbed the first flight to Albuquerque, where Bowie had filmed “The Man Who Fell to Earth” (1976). When Morgen arrived, he took a cab to the train station and hopped aboard an Amtrak, heading west.

“Being in transit was an important theme in David’s life,” he said. “He talked a lot about riding the rails through the West. And a lot of songs that he wrote happened during some of his trips across America.”

Morgen pulled out his notes; his phone, packed with all the albums; and his copy of “The Hero With a Thousand Faces” by Joseph Campbell. “I was thinking about ‘The Iliad,’” he said, “and I started to see David’s journey. Not all that dissimilar — but he was creating the storms for himself.” Suddenly, the script for his film, already three years in the making, began flowing.

That trip was one of the many ways in which Bowie, the protean rock icon who died in 2016, influenced Morgen, an atmospheric documentarian known for showcasing big, world-changing personalities in “Kurt Cobain: Montage of Heck”; “The Kid Stays in the Picture,” about the Hollywood producer Robert Evans (co-directed with Nanette Burstein); and “Jane,” about Jane Goodall.

Morgen’s opus about Bowie, “Moonage Daydream,” which opens in theaters and IMAX on Sept. 16, is billed not as a traditional documentary but as an immersive experience. It’s equal parts psychedelic and philosophical — a corkscrew into Bowie’s carefully constructed personae, assembled entirely from archival footage and audio, some of it rare and never broadcast before. The effect is “a hallucinatory jukebox doc with killer subtext,” as one reviewer wrote, appreciatively, after it premiered at the Cannes Film Festival this spring.

Though there have been other documentaries, and many books, this is the first project that had the full cooperation of Bowie’s estate, and total entrée to his voluminous archives. The songs have been stripped and rejuvenated for the soundtrack, and any narration there is comes from Bowie himself.

But that level of intimacy proved its own challenge as Morgen, the writer, director and producer, grappled with a mountain of material and wound up the sole editor after the production ran out of money. “I felt very confident that the through line of David’s artistic life was chaos and fragmentation,” Morgen said. He had heard those ideas come up again and again in Bowie’s interviews from 1971 on, and eventually decided to embrace them himself.

Tony Visconti, Bowie’s longtime collaborator and producer, who served as a resource for the audio, came away impressed with the way the film kaleidoscoped the visuals, narration and music. “There is technical wizardry in all that,” he wrote in an email. “And when seen and heard, especially in an IMAX theater, you will get the most Bowie ever — sensory overload.”

“David would be very impressed with this film,” he added.

What Morgen didn’t realize was how much making the film would change him, especially after he had a debilitating heart attack, at 47. He flatlined and was in a coma for a week, he said in a phone interview. He emerged with a mind-set that shaped his approach to the story and refocused his own life, as a married father of three. Perversely, the driven Bowie helped Morgen, now 53, a fellow workaholic, find equilibrium.

And he needed it, when he was editing, entirely solo, during the first peak of Covid (his health scare made him extra-cautious). “I was sitting alone in this building, making a film about an artist whose stock in trade is isolation, and how to channel it creatively,” he said. “So I felt that he was consistently describing the world that I was inhabiting.”

Early on, he had visited Visconti in his New York studio. “We were in the room where he recorded David doing ‘Blackstar,’” the album Bowie released two days before his death, Morgen said. “It was quite intense.” Visconti played him “Cygnet Committee,” a prog-y folk-rock track off Bowie’s second album, stripping out vocals. The song, written when Bowie was around 22, ends with a repeated lyric: “I want to live.”

“David was crying throughout the performance,” Morgen said.

That sort of emotion — ravenous and vulnerable — set the tone for the film. “Moonage Daydream” was five years in the making. It took Morgen and his team over a year just to transfer hours of concert and performance footage, images of Bowie’s paintings and other content from the Bowie estate, along with additional footage acquired by Morgen’s archivist, and about two years to watch it all.

But the movie is hardly completist. There are no interviews with anyone else, and no mention of, for example, Iggy Pop, whom Bowie holed up with in Berlin during one of his most creatively fertile periods, or Nile Rodgers, who helped him reinvent his career as a pop artist in the ’80s. The sexual voraciousness and drug addiction that usually feature heavily in Bowie’s story are referenced only with montages and jumpy interview clips. (“Do I need to spell it out? It seems kind of blatant to me,” Morgen said of one where Bowie appears sweating and grinning maniacally.) Though the movie dips into his childhood and family, it glosses over his personal life until his marriage to Iman, the model and entrepreneur.

“It was never designed to be a film about David Jones,” Morgen said, using Bowie’s given name. Every time Bowie was onscreen, including interviews, was a performative moment, Morgen added, and that’s what he wanted to capture. “It’s a film about Bowie in quotations.”

He had first pitched Bowie directly on making a hybrid nonfiction film in 2007, when the artist was already wondering how to showcase his archives, but the timing and scope wasn’t right, Morgen said. He was exploring a similar nonfiction idea with the remaining Beatles when Bowie died, and a call with Bowie’s longtime business manager, Bill Zysblat, resurrected the film.

Bowie’s estate gave him unfettered access but not much guidance, Morgen said. At one point, he wanted to discuss what direction to take. “Should we go more toward ‘Bohemian Rhapsody,’” the 2018 Queen biopic, “and create a kind of populist singalong?” he asked. “Or should we do it more in the spirit of Bowie, which may be a little more adventurous?” And they said, “Well, that’s your problem.” (He employed Paul Massey, who shared an Oscar for sound mixing on “Bohemian Rhapsody” — which Morgen said he watched 14 or 15 times — for “Moonage Daydream.”)

The estate, which is overseen by Zysblat, and includes Bowie’s family — his widow, Iman; their daughter, Alexandria Zahra Jones; and his son from his first marriage, the filmmaker Duncan Jones — declined to answer any questions, but they support the film. “Brett Morgen has created a stunning testament to David’s lasting influence on the world,” they said in a statement delivered through a representative. The estate has continued to earn money, selling Bowie’s songwriting catalog to Warner Music for an estimated $250 million this year, as his popularity (more than 1 billion streams on Spotify) and reputation as a cultural visionary — especially when it comes to technology and music — has only grown.

For Morgen, one of the most illustrative points was the way Bowie behaved in many interviews, often with people who clearly did not get him; one, trying to suss out just how alien this gender-bending artist was, asked if he’d had a teddy bear as a child. And yet, “I never saw David talk down, be disrespectful, short, annoyed,” Morgen said.

Maybe this was just politesse as a disarming tactic, but Morgen saw it as something deeper — an ability to seek connection and profundity in any situation. It was a message that he tried to convey in the film. Bowie was “trying to make each moment matter,” he said. “It’s a life-affirming sort of road map, on how to lead a satisfying and complete life.”