Moving in strange circles

The choreographer William Forsythe's latest project uses light, motion - and no dancers. He explains himself to Jenny Gilbert

LONDON'S Roundhouse, that great grey lump of a place in Camden, means very different things to different people. To railway historians it is a unique and poignant relic of the glorious days of steam. To theatregoers it's the failed promise of an arts complex that never happened. To a colony of rats, it's home. But the rats' days are numbered. Reg, the caretaker, who runs a daily watch in this dark, dank echo-chamber of a place, has hired a ferret for a day. Something's going to happen to the Roundhouse. This time it really is.

Artangel is an organisation whose business is to nose out unexpected urban venues and put artists in them. Each Artangel project is shaped by the physical and historical characteristics of the place, and each is a unique collaboration, sometimes between art forms and always between artists and audience. Rachel Whiteread's plaster-cast House was one project; in another, Laurie Anderson and Brian Eno mapped out a labyrinthine journey through a furniture storage depot in Wembley. Later this month, the 20,000 square feet of the Roundhouse interior will be transformed by the American choreographer William Forsythe into a "Tight Roaring Circle". Don't go expecting dance, though.This will be something else.

Choreography to Forsythe and his long-term collaborator Dana Caspersen is not about steps, it's about "making a frame". But quite what will be within that frame in the Roundhouse was at first a thing of some mystery, even to the artists, apparently. Forsythe, whose first radical act as the new director of the Frankfurt Ballet 12 years ago was to chuck out its entire classical repertoire, is famous for his drastic deconstruction of the ballet vocabulary: here a shoulder slipping from its socket; there an ankle whipping past an ear. But there are no double-jointed Sylvie Guillems in this project - no dancers at all as such, just "choreography".

Forsythe tries to explain. "Choreography exists before the dancing happens. It's to do with someone organising the relationship in the room." He tries a historical tack. "As we know it today, dancing is a primary art and choreography a secondary one. While dancing seems to be becoming more and more natural, choreography has become arch and artificial. But it originally meant the drawing of lines and circles for a chorus. So ours is the art of drawing circles, of circularity, of circulation. I'm really getting in circular synonyms for this project ... so what we're doing is ... uh ... creating a kind of circulation with fields of light and movement."

Caspersen, a steady, diminutive presence beside his 500-words-a-minute, six foot three, quietly intervenes. "We're focusing on ways to direct gaze. In choreography that's what you're doing all the time, directing people to where they should look. Here we're directing them to the interior of an interior, and the exterior of an interior." Forsythe leaps back in. "Just like in ballet! En dedans ... en dehors. Inside and out. No one can have the same experience because there are lots of different things being shown, and some are very intimate and the project involves over three hours of it all."

"Four actually," says Caspersen. "It's open for four hours a day."

"Anyway," continues Forsythe, "it's not a performance that starts, then everyone claps at the end. No no no no no no NO!"

"It's a kind of landscape of events," Caspersen puts in firmly. And I think we get the picture.

I am meeting Forsythe on a very bad day. He has a humdinger of a head- cold, having spent the previous day "auditioning" in the dark, unheated Roundhouse. When first introduced to it, he had "almost fainted ... such a beautiful space". Now his reactions seem more sober. How had the auditions gone? He looks glum. "None of them could do what we wanted. What we want is very subtle." So subtle, in fact, that they eventually decided to do without any performers at all.

By the time "Tight Roaring Circle" opens, the Roundhouse will be transformed. There will be heat. There will be light. There will be a variety of "internal structures" in addition to the Roundhouse's own; most notably its circle of 24 iron pillars topped with decorative arches and spandrels and 24 iron ribs which curve majestically up to a vast domed roof. Who but the early Victorians would have expended such care over a garage for 23 steam engines? Too bad the huge central turntable - a device for revolving engines into their berths - had its innards removed long ago. Forsythe the boy genius would have loved to play with that.

Forsythe the adult polymath will play instead with light and motion. Quite what will be in motion remains to be seen. At the same time his sound man, Joel Ryan, a pioneer of digital music systems, will "tune and play the building as if it were some vast musical instrument". Wow. Nineteenth- century engineering meets galloping late-20th-century technology. Stiff- collared Robert Stephenson, who designed the New Great Circular Engine House in the early 1840s, would have appreciated the irony. He himself lived in a time of such rapid change that his creation was obsolete only 15 years after it was built, and demoted to a humble goods shed. Which leaves us to wonder: how will Nineties installation art be regarded in the year 2012?

! 'Tight Roaring Circle': Roundhouse, Chalk Farm Rd, NW1 (0171 336 6803), 26 Mar to 20 Apr.