IT'S NOT EASY putting together a vast regional survey like Yerba Buena Center for the Arts' triennial "Bay Area Now." Shows like this have to please an entire community of artists, bring a sense of cohesion to a broad sampling of artwork, and, at their best, present a curatorial thesis. BAN could easily come off as a smorgasbord of painting, sculpture, video, and/or whatever else. Such a show might be diverting, but it never quite makes for a satisfying meal.

"BAN 4," organized by René de Guzman (who has cocurated the other three "BAN"s), along with new assistant curator Berin Golonu, does seem diverse, though the shadow of the so-called Mission School, which previous "BAN"s have done much to publicize, hangs over this endeavor in the way it presents a next generation of the handmade, the humble, and the drawn. Yet you have to work to find thematic threads here, or the reasoning behind some of the inclusions.

To be sure, there is interesting art. Among my favorites are Neck Face's giant metal monster sculpture; Libby Black's elaborate paper-and-glue re-creation of a Kate Spade retail lifestyle bubble; Adriane Colburn's superintricate, eco-conscious paper cutout map of San Francisco's sewage infrastructure; Chris Kubik and Ann Walsh's elegant sculptural-audio presentation of violent-sound-effects catalogs; and Christine Shields's portraits of Mission District-associated scenesters that capture their essence – the latter contribute to a somewhat cohesive thematic thread of portraiture.

More surprising is the way that artists whose work I admire or had looked forward to seeing seemed to evaporate from my mind after multiple visits: Liz Cohen's complex and attractively lurid project of cultural transformation and assimilation by turning herself and a car into icons of customized hot rod culture; Christian Maychack's intriguing site-specific acts of architectural morphing; Chris Ballantyne's painting installation, which coolly depicts the clash of nature and suburban culture; Xylor Jane's mathematically derived drawings; and Robert Gutierrez's fleshy, surrealistic landscape paintings.

Without the rollicking good energy of the opening-night party, a clear indication of the Bay Area's interest in forging community and having fun, the show itself seemed surprisingly inert. "BAN 4" features an interesting range of artists – known up-and-comers, discoveries, and a few head-scratchers – yet the grouping never quite congeals. The whole is less than the sum of its parts.

Why? For one, the design and layout of the show, particularly in the main gallery, is too jumbled to allow the artwork to sparkle. Josephine Taylor's delicate renderings of creepy interpersonal and sexual situations lose a sense of quiet confrontation in the cavernous room. While allotted a large amount of space, Colburn's map feels squeezed; and Tommy Becker, an artist whose work I'd heard much about but had never seen, shows poetic video works in an open area, where I had a hard time concentrating on them. Becker's projection was right next to Emily Prince's visually and metaphorically massive ongoing project of drawings of every US military casualty in Iraq, a memorial that needs more space for reflection than it's given here. (The Prince work is conceptually admirable, yet its chartlike literalness reads more treacly than trenchant.) One friend at the opening whispered to me that the large room looked like a freewheeling MFA show – not necessarily a bad thing, but perhaps not what the organizers were aiming for, nor what visitors expect.

The show includes a number of projects that require audience participation to complete, and to explore themes of community. It's an interesting and timely impulse, but one that doesn't come off well in the galleries, where absence is conveyed more insistently than substance. When I visited the show on a Saturday afternoon, Ted Purves's Momentary Academy, a series of classes and a spin on arts education, seemed like an empty, albeit nicely designed, schoolroom. Margaret Tedesco's installation seemed cryptic without its performance element. Kate Pocrass's Mundane Journeys, a tour of the neighborhood, is represented by a pile of handsomely designed broadside maps; its major component takes place elsewhere, at other times. These works might be great, but the presentations themselves don't convey what it might be like to participate in them, or offer much in the way of visual appeal to lure viewers back for more.

The only participatory piece that was operative was Edie Tsong's drawing exchange, in which the artist appears in the gallery via Webcam and renders a viewer and vice versa. The piece brings up cyber-connection dialogues that are so turn-of-the-millennium and results in drawings that aren't particularly intriguing. I couldn't have been less interested.

Previous "BAN" installments included projects that emerged from the fray and became works that people still associate with the exhibition: pieces like Jim Christensen's sculptural recreation of his kindergarten classroom, in "BAN 2," or Kota Ezawa's OJ Simpson trial cartoon, in "BAN 3." There are no such touchstones in this show, which may be a sign of the times or of a curatorial intention – are they suggesting that the Bay Area now is aesthetically wide-open and amorphous? Regardless, this snapshot of our artistic moment is a bit of a blur.

'Bay Area Now 4' runs through Nov. 6 (downstairs) and through Sept. 25 (upstairs) at Yerba Buena Center for the Arts, 701 Mission, SF. Thurs.-Sat., noon-8 p.m.; Sun. and Tues.-Wed., noon-5 p.m. $3-$6 (free first Tuesdays). (415) 978-ARTS.