After 20 years, the black bronze allegorical figure of Diana by Anna Hyatt Huntington is gone from the elegant spiral-staircase-lined rotunda at the 186-year-old National Academy Museum and School at 1083 Fifth Avenue (a half-block north of the Guggenheim Museum). In its place is a crumpled mass of chrome car bumpers and rusty automotive steel by second-generation Abstract Expressionist (and National Academician) John Chamberlain. Also absent is the academy's homely little gift shop that greeted visitors to the museum, replaced by an open entranceway, with a listing of the year's new academicians on one wall.

These changes, designed to help bring the 19th-century institution -- founded as an association of artists and architects -- into the 21st century, are part of an 18-month-long, $3.5 million overhaul that is being unveiled this weekend, starting Sept. 16, 2011, with several new exhibitions -- and free classes at the academy school. The renovation was overseen by architect Jane Stageberg of the New York firm Bade Stageberg Cox; the building committee included architect Bruce Fowle, an academician and president of the board, and academy director Carmine Branagan.

The major offering is certainly the full retrospective of painter Will Barnet(b. 1911), dubbed "Will Barnet at 100," Sept. 16-Dec. 31, 2011, organized by museum curator Bruce Weber. The selection of 43 works includes galleries devoted to the artist's WPA-era paintings of children (vaguely suggestive of Rufino Tamayo), his abstract Indian Space paintings, and works in the figurative style that led to his widespread fame in the 1960s.

Also on view is "An American Collection," a salon-style installation of approximately 100 works the museum's 7,000-work collection and a "Panorama of Great Artist Portraits" (members of the academy at one time were required to do a self-portrait). One gallery is now devoted to "Contemporary Selections," and currently features abstract color works by Bill Jensen, Harriet Korman, Melissa Meyer, Judith Murray and Stephen Westfall