Twenty years ago, Carmen Beuchat's intricately layered, multimedia dance-theater work titled "Exactly How It Is," performed at the Washington Project for the Arts last night by Beuchat and collaborators, might well have seemed daring, inventive, attractively bizarre and provocative. The attributes that would have produced such impact haven't lost their intrinsic potency, but our responses to them have been conditioned by all that's passed under the bridge artistically since the early '60s.

Today, Beuchat's helter-skelter charade looks less like radical chic than it does like radical antique--an avant-gardism gone stale in its own cliche's. "Exactly How It Is" has the veneer, the atmosphere and the techniques of the Judson Dance Theater era, and the "post-modernism" that followed, down pat, but the originality, the vivifying spark and the sense of outrageous revelation that gave these precedents their power to stir and inflame are missing.

Beuchat studied in her native Chile with Kurt Jooss' colleague Sigurd Leeder, and had an early career as a ballet dancer. In this country, she entered the mainstream of postmodernism as a founding member of Kei Takei's Moving Earth, and as a dancer with Trisha Brown's company for five years. Her own work discloses an indebtedness to Takei (in particulars of movement, in ritualisms, in visual and sonic accessories) and others, including Meredith Monk and Yvonne Rainer. Like Takei's "Light," "Exactly How It Is" is a magnum opus that has evolved over a period of years by accretion.

Still, there's an individual imagination at work here, and ingenuity as well. The piece is like a compendium of postmodern devices--slide projections; a TV set tuned in "real time" to last night's programs ("Shogun," a "Star Trek" rerun, "Dallas," etc.); dancers interacting with objects such as cardboard boxes, colored cellophane, folding chairs, scraps of newspaper, a pillow, a papier-ma che' storm cloud; sounds ranging from percussion ostinatos to "The Firebird" to rock 'n' roll to gurgling water; fragmentary and cryptic verbalizations in English, German and Spanish, as well as clappings, hissings and snatches of song; and movement idioms running the gamut from repetitive marching and spinning to convulsive seizures, animal mimicry, martial arts, flamenco and academic ballet.

All this was delivered last night by Beuchat, Kristen Moneagle and Victoria Rue not only with authority, conviction and precision, but also a fairly strong sense of personal identity among the dancers. And the whole performance drew a heavy sense of mystery from the surreal collage tradition it strove to extend.

Yet the result seemed tediously impenetrable. No controlling, central image or theme emerged to illuminate the chaos, or even to convince one that all the pieces belonged to the same puzzle. At one point, one of the dancers, presumably in self-parody, exclaimed, "If we slosh around here long enough, we're bound to come up with a few good ideas." A few good ideas were indeed in evidence, but no single governing idea to weld the piece into a coherent statement. About halfway through, one saw that the fog wasn't going to lift, and that the repertoire of effects would continue to multiply but neither deepen nor coalesce.