Some artist biopics trace the linear flow of their subjects' lives from start to finish; others center on their subjects' careers, noting how and why they developed their aesthetics. Pie In The Sky: The Brigid Berlin Story does neither. It mostly just tosses intriguing moments at the screen, seemingly at random, just to see what sticks. The film's eponymous focus was an Andy Warhol confidante who obsessively taped all her phone conversations, documented her surroundings with Polaroids, and allowed Warhol to record her wandering rants, so there are many such moments to explore. The film footage of Berlin's life begins practically at birth; her father, the wealthy and well-connected head of the Hearst newspaper conglomerate, shot copious home movies of her as a baby and a young girl, often clutched in the arms of her traditionalist, image-conscious socialite mother. After Berlin, pudgy and orally fixated from an early age, was forced through a series of exclusive schools and expensive fat farms, she rebelled and left home. She soon fell in with Warhol's Factory crowd, supporting Warhol emotionally and artistically while creating her own artworks, notably by pressing her paint-covered breasts against paper to create "tit prints" as crowds of fans watched, and by phoning friends and family who weren't aware the conversations were being broadcast to a theater's audience. Vincent and Shelly Dunn Fremont's documentary combines archival films of all these events, interviews with Berlin friends and admirers (most notably John Waters, who gushes over Berlin's work and describes her as having "great confidence, for a fat girl"), and present-day interviews, in which the once-260-pound Berlin, at age 60, is briefly trim, though still frighteningly obsessed with food. In a series of rants reminiscent of her '60s film pieces, she documents her low-fat meals in minute detail, but returns time and time again to her love of key lime pie. By the film's end, she's off the wagon, eating several pies at a sitting and vibrating maniacally around her intimidatingly rococo home like Ellen Burstyn in Requiem For A Dream. Like much of Pie In The Sky, this sequence is riveting, yet appallingly raw; Berlin is so clearly in emotional pain that filming her implies a brutal voyeurism. It would help if Pie treated her more like a human being and less like a fascinating but opaque puzzle: The documentary showcases her most neurotic and unpredictable behavior, but rarely attempts to get at its causes. Nor does it examine how she developed her art, or how she feels about it now, or even whatever happened to all those Polaroids and audiotapes. Like Terry Zwigoff's Crumb, Pie is bruisingly, uneasily compelling. But the film's blend of intimacy, merciless accuracy, and unwillingness to probe below the shocking surfaces begs the question of whether this is exploration or exploitation.