With three major New York shows in the last year alone, Pablo Picasso is making Jeff Koons look underexposed. Yet the Museum of Modern Art’s fall exhibit “Picasso Sculpture” is not a case of market saturation. For all the artist’s fame, his sculpture remains largely unknown. Reduced in the popular imagination to a Sunday hobby picked up late in life at Vallauris, his important 3-D output was first (and last) exhibited on these shores in 1967. “At the time, the mere fact that these sculptures existed was big news,” cocurator Ann Temkin says. “Now, we’ve realized it’s Picasso at his most personal.” The 150-piece survey considers the painter’s radical career-long reappraisal of the form. “As a sculptor, he’s self-taught,” cocurator Anne Umland says, “so there’s this wonderful improvisation and ingenuity. He’s devising new solutions, with an immediacy that feels utterly contemporary.” On view September 14 through February 7; moma.org.