He directed hits like ''Bruce Almighty,'' ''The Nutty Professor,'' and ''Ace Ventura.'' Then everything changed.

Tom Shadyac used to live at a 17,000-square-foot estate on seven acres, a spread so vast it took him a good half hour to give a visitor a tour. It was exactly the sort of home you’d expect the director of smash comedies like Ace Ventura: Pet Detective, The Nutty Professor, Liar Liar, and Bruce Almighty to own. At a certain point, though, the spoils of a successful Hollywood career — the big house with the full-time staff, the limousines, the multimillion-dollar paychecks — began to feel excessive, wasteful, and just plain wrong. Shadyac decided he couldn’t stomach that life anymore.

These days, he can give a tour of his home in 10 seconds with a single sweep of his arm. In late 2003, Shadyac sold his estate in Pasadena, started to divest himself of his possessions, and by 2007 had downsized to a modest 1,000-square-foot mobile home in a seaside trailer park called Paradise Cove. Granted, this is Malibu, not Mobile, Ala. — units in Paradise Cove routinely sell for more than $1 million. Still, the radical transition brought turbulent moments. ”The first night I was here, my neighbors had a party on their deck, and I thought, ‘My God, what have I done?”’ says Shadyac, 52. ”I thought that I’d made the biggest mistake of my life, that this was crazy.” He laughs. ”Which is what a lot of my friends were telling me.”

Shortly after Shadyac moved into Paradise Cove, his life got upended again, this time by forces beyond his control. In September 2007 — just a few months after his first box office comedy flop, Evan Almighty — he got into a bicycle accident while visiting relatives in Virginia. The fall initially appeared minor, but the next day he felt wobbly and disoriented — and from there things got worse. His brain no longer seemed able to filter out extraneous stimuli. Sounds were too loud. Lights were too bright. He couldn’t carry on simple conversations. Diagnosed with post-concussion syndrome, Shadyac fell into a paralyzing depression, spending days in the bedroom of his mobile home with the curtains taped shut. ”I couldn’t even make a phone call,” he says. ”Just going to the store was torture. I literally thought I was going to die — This is it, I’m done. So I asked myself, ‘If I have one chapter left, what do I want to do?”’

As he slowly recovered, Shadyac — like the comedy director played by Joel McCrea in Preston Sturges’ 1941 classic Sullivan’s Travels — decided to make a movie that would be a complete departure from the broad laughfests he’d trafficked in. No people talking out of their butts. No fat suits. Instead the movie would delve into spiritual questions that had been rumbling inside him for years: What is really important in life, and how can we fully wake up to it?

The result is Shadyac’s new documentary I Am, which opens in select cities Feb. 18. Completely self-financed for around $1 million and shot with a crew of four people, I Am explores the ways in which the director believes humankind has lost its spiritual compass: the materialism, the dearth of compassion, the despoliation of the planet. He interviews scientists, philosophers, authors, and moral leaders, including Desmond Tutu, Noam Chomsky, and Howard Zinn. He also connects himself to a dish of yogurt via electrodes to demonstrate how all living things are interrelated. Looking at his own life, Shadyac concludes that what he once thought were the measures of success were actually symptoms of a soul-corrupting mental illness that the Cree call wetiko. ”As a movie director, I stood on the top of the heap and said, ‘I’m more valuable,”’ he says. ”I don’t believe that anymore.” Not surprisingly, Shadyac’s extreme downshifting has aroused some cynicism. On Internet comment boards, some have taken potshots at him, dismissing I Am as ”Hippie Bulls—: The Movie” and wondering if he is simply trying to reboot his career after the high-profile bomb of Evan Almighty.