Don't give up on your desire

Though he has moved from notorious performances into architecture Vito Acconci still deals with the diversity of human craving

Followers of the strange adventures of the modern have, alongside their knowledge of great works actually seen, surrogate experience of great moments missed, known only through photographs and second-hand descriptions. Moscow parades with outfits by Vavara Stepanova; Yves Klein's Leap into the Void, complete with judo fighters to catch him. Or Kurt Schwitters's Merzbau, biomorphic environments collaged from fragments of the actual world to create peculiar escapes from it. And Robert Smithson's glittering Spiral Jetty, before it was submerged under the Great Salt Lake.

Followers of the strange adventures of the modern have, alongside their knowledge of great works actually seen, surrogate experience of great moments missed, known only through photographs and second-hand descriptions. Moscow parades with outfits by Vavara Stepanova; Yves Klein's Leap into the Void, complete with judo fighters to catch him. Or Kurt Schwitters's Merzbau, biomorphic environments collaged from fragments of the actual world to create peculiar escapes from it. And Robert Smithson's glittering Spiral Jetty, before it was submerged under the Great Salt Lake.

Among these moments missed are the early performances of Vito Acconci in New York. In 1969 with Following Piece, Acconci followed randomly-chosen individuals in the street until they entered a building. He did it over a month, for minutes or for hours, without alerting the individuals. In 1971 he told secrets, "which could have been detrimental to me personally", to whoever chose to visit an abandoned wood shed on the Hudson river at specified hours of the early morning. And most famously, in the Sonnabend Gallery, he built a ramp - it looked as though the whole back of the gallery floor had been tipped up - and lay under it with a microphone, fantasising about the presence of visitors to the gallery and masturbating.

That last work, Seedbed, became notorious, but Acconci's works were not actually unhinged. They always took place in carefully-defined ways, however risky for performer or audience. Acconci has been described by Donald Kuspit as acting out the loneliness of the crowd, the longings customarily hidden or forbidden. There is no sudden sexual or social release: we have to think about why Acconci did those things, and why we don't, might, should or perhaps should not do them. The last possibility is not ruled out. His early works retain an art-like formality, but link unusually into the social loosening underway, as few artworks of that time usefully did.

Fortunately, Acconci was no purist about documenting performance. He made brilliant works in audio, film and video: such as Theme Song (1973), where, lying by the sofa on his living-room carpet, he presses his face close to the camera and curling his legs and stocking feet back and forth, implores the imagined and unknown viewer to join him. He boasts, begs, smokes cigarettes. The extraordinary voice seduces you. He puts on records and sings along, weaves the lyrics into his argument, exemplifies how clichéd and vulnerable anyone's longing is.

Film and Video Umbrella toured a selection of these works three years ago. Direct influence is not easy to demonstrate, but Acconci's humour and intimate daring really does chime with works by better, younger artists such as Steve McQueen and Jaki Irvine. Some of Acconci's classic works will be in the upcoming City Century show at Tate Modern, if you want to test out my high praise. Other works will be in a group show at the RCA in March, put together by students on the curating course who clearly think Acconci's hot. It's always good to think about why some artists are being thought about again, and Arnolfini in Bristol is spot on in showing what Acconci - now 60 and in possession of a voice perfected by chain-smoking - is doing now.

That long preamble is probably needed for this show, because these recent works are architectural plans and schemes, put together with a practice called Acconci Studio. It is not a retrospective, desirable as one might be. Acconci's move to public projects and architecture - he had wound down the audio, film and video works by the Eighties - seems to admit no going back. The show looks like an architecture display: models, briefs, text panels, sites and solutions, projectors firing away at skied screens, tensioned wire bench seating to pause on. But transforming the whole experience is Acconci's disembodied voice, amplified, and now, a good interval lower, resembling that of the computer in Godard's Alphaville.

The voice guides you around the schemes, emphasising how they would be experienced by people encountering them. The glass bubbles in the Munich Marienhof scheme are intended to seem "as if they have swelled up from below". (The diamond-shaped swimming pool in its sphere can be glimpsed from beneath.) The fractal splintering of chunks of land, tilted out into a water channel in a plan for the Netherlands, would mean visitors would jump from chunk to chunk and to rediscover the pleasures of a beach with big rocks, but in an urban setting.

Earth is perceived as a pliable plane, permitting folding, and water is clearly a fascination. In a scheme in Germany for a hill rich in mineral springs, the water from the outlets is channelled into a fantastical network of elevated pipes, which drain down and converge at visitor centres; these are built as though the land is being peeled back. Water is channelled over, not under the land, and even flows transparently over a major road. In another scheme skied lighting tubes illuminate a neglected urban river. Suspended triangular mirrors provide glimpses of water to parts of the town further away, and floating walkways snake along, rising and falling with the tide. Names catch the eye: Knutsford Road; Witherspool Causeway. We are in England, Warrington; this is the Mersey. Meanwhile, on a roundabout on the A13 near Dagenham, cars activate rings of turf, which rise up to make illuminated waterfalls. If there are no cars, the waterfall sinks back into the ground.

This remains something other than an architecture show. The sound of Acconci's voice transforms it, as does the formal interest in showing the models at angled planes, as the parks and gardens tilt and buckle; a bit like that ramp under which Acconci once fantasised to unseen spectators via a microphone. But before you start to think it's all fantasy, it should be pointed out that the Acconci Studio has been getting results. In Klapper Hall, Queens, large balls, seemingly of granite, but sliced open to provide possibilities for social encounters, rolled off the drawing board and into the courtyard. In an urban park in the Netherlands, water actually has invaded the land and bits have broken out into it, bearing lampposts and stray trees.

Acconci can seem like a visionary planner from the old days. The planner as God, a land artist who makes urban landscapes obstructive to our passage as well as delightful, aggressively friendly and not always even that. But a planner whose schemes might be impressive because they refuse a marketist language of end-user classification and social despair. They have a generous estimate of the intelligence of the people who will encounter them and use them; as fun, as solitary sculptural experiences, as social and civic possibility.

The way Acconci's work has evolved is exemplary in that it doesn't ruin the achievement of the early works - Lou Reed comes to mind, as a counter-example - and in reaching for new ways to explore the underlying motivations and questions he sets himself to understand. The fantasies of the crowd, of the crazy person next door and the crazy person you might be, too; the unknowable diversity of human wishes. Whenever I think again what Lacan meant by saying, "don't give up on your desire", I will hear it in Acconci's deep and sexy, bubbles-through-lava voice.

Vito Acconci and Acconci Studio, Para-Cities: Models for Public Spaces, Arnolfini, Bristol, to 4 Mar

Jaki Irvine, Ivana's Answers, Delfina Project Space, London, opens Friday