The Serpentine does unsung heroes as well as it does art-world superstars, as Anthony McCall's new exhibition shows.

McCall, 51, is an experimental British film-maker who moved to New York in the Seventies. There he became an unduly peripheral figure on the minimal and conceptual art scene and is now, consequently, ripe for reassessment: this is his first major London exhibition.

Like his legendary American peers Sol Le Witt and Richard Serra he was searching for poetry in the simplest - "purest" they said at the time - use of materials.

Serra has made a life's work enumerating what can be done to solid forms with large slabs of rusting steel (leaning, throwing, balancing etc). Le Witt built modulating geometric structures painted gleaming white. McCall makes art out of the formal properties of film - time and light.

The Serpentine's well calculated installation begins with an arid room of the neat geometric drawings that are de rigueur for conceptual artists, including one arcane work of diagrams of the diminishing number of people watching one of the artist's works from five minutes after it begins, to 12 hours. The curators are being ironically arid, it turns out.

These analytical works do not prepare the viewer for the projections that follow - among the most beautiful and euphoric experiences that minimalism has ever produced.

In blacked-out rooms filled with dry ice, McCall's projectors trace slowly moving white lines - an undulating wave, two lines extending and intersecting - across the walls of the gallery.

The artificial smoke turns the beams of light into quasi-solid geometric shapes of cones and ellipses, through which visitors can pass. It creates the illusions of being able to walk through solid objects and of one's body becoming transparent.

These are terrifically original and intellectually solid works of art, which could be described as installations, sculptures, drawings and "dematerialised", all at once. But they are also thrilling in the way that works of art that convey the sensation of transcending the limits of the body are. It's art as science fiction.

• Until 3 February. Information: 020 7402 6075; www.serpentinegallery.org