Robert Altman was a legend behind the camera, but the Oscar-nominated icon behind such classics as “Nashville” and “McCabe & Mrs. Miller” dominates the screen in a new documentary devoted to his life and work.

Entitled “Altman,” the documentary airs on Epix on Aug. 6 at 8 p.m. and will also have a limited theatrical release. Ron Mann (“Comic Book Confidential”) produced and directed the picture.

Altman serves as a raconteur and a tour guide, as the picture dissects the over-lapping dialogue, non-conformist characters and relentless genre-hopping that gave birth to the term “Altman-esque.”

Altman was a cinematic genius, but he also undoubtedly benefited from the collapse of the studio system in the 1960s, which gave birth to a generation of edgier auteurs such as Martin Scorsese, Hal Ashby and Francis Ford Coppola. Together they pushed the boundaries of mainstream film in a way that wasn’t seen before and hasn’t happened since. However, friends say his zest for life would have enabled him to succeed whatever the circumstances.

“Robert Altman would have had to exist at whatever time he could exist,” said Elliott Gould, who worked with the director on “The Long Goodbye” and “M.A.S.H.” “Maybe he would have been making great pancakes instead of films, but he was just a force of nature.”

Altman died of leukemia in 2006 at the age of 81, but the new film features reams of interviews with the director on his distinctive, highly collaborative approach to film-making, as well as rare behind-the-scenes footage from his decades of shooting to the beat of his own drummer.

“It’s great because the thing we always wanted to know about Bob for a long time was how much do the films represent him and how much of Bob is in the movie,” said Bob Balaban, a producer and actor in “Gosford Park.” “Having him personally take you through this great body of work is an enormous treat.”

The picture draws extensively on Altman’s archives at the University of Michigan to document both the highs and lows of his time in Hollywood, during which he moved from the center to the periphery and back again. The savage critical reaction to 1980’s “Popeye” brought the director back down to earth and he struggled to get financing for projects, focusing primarily on the stage, until his triumphant return with 1992’s “The Player.”

Kathryn Altman, his wife of more than four decades, said even when banished to the studio wilderness, her husband didn’t let himself get depressed.

“He never stopped thinking and planning his next film,” she said. “There was no down time. He just kept working.”

Mann’s film also gives a sense of the loose nature of Altman’s sets, a method of controlled chaos that allowed actors to venture outside their comfort zones.

“It was a haven for actors,” said Balaban. “He was like a kid in a candy store. It was like his oxygen to be on a movie set.”

Not that there weren’t conflicts. Gould admitted that his close relationship with Altman got off to a rocky start.

“At the beginning, Bob struck me as being my enemy,” said Gould. “He was so anti-establishment, so pro-nature. During the course of our working together, he turned out to be more like my father.”