Design: Transparently good ideas

Transparency is all the rage. And this time round we're not talking naughty negligees or Iggy Pop's trousers. On the high street and in the smartest homes, see-through is stylish. Designers and architects are taking full advantage of new technologies in glass and plastics with some spectacular results; last year's fashion show by Alexander McQueen for London Fashion Week saw models sashaying down a sparkling Perspex catwalk, while architect Piers Gough won awards and plaudits for the Glass Building in Camden, north London, which uses huge sheets of curved glass, double-glazed and tinted against solar gain, to wrap its loft-style apartments in walls of window.

At the cheap and funky end are see-through inflatable chairs and cushions, their airy interiors variously filled with bright red feathers or tiny polystyrene balls; handbags which flash their innards; see-through mules for showing off Cinderella-perfect toes and see-through shower curtains for perfect bodies. Meanwhile, Perspex furniture is creeping out from under the shadow of kitsch. The new "La Marie" chair by Philippe Starck for Kartell, which is moulded from a single piece of polycarbonate and is completely transparent, leads the pack. Light, inexpensive (it retails for pounds 95) and barely there, it floats in an interior like a sketch of a chair more than its solid reality, picking up colours and patterns from its surroundings.

Bobo, a design duo who specialise in Perspex and are best known for their jokey, printed lavatory seats, also make some seriously beautiful transparent furniture. Nick Grant and Tanya Dean work closely with ICI, manufacturers of Perspex, and are passionate about their medium. "Unlike mass-produced glass, which has a distinctive green tinge from the lead used in its production, Perspex is crystal clear," says Nick. "Being able to see right through a material gives you scope to play with light and reflection as well as form."

The unique combination of the solid and invisible offered by clear plastics and, more significantly by glass, has long been a holy grail for architects. Le Corbusier famously characterised the history of architecture as "the history of windows" - a struggle "on behalf of light against the obstacles imposed by the laws of gravity". As the century draws to a close and glass is cheaper, stronger, safer and more perfectly transparent than ever before, that battle has been won. Glass is everywhere, inside and out - doors, windows, ceilings, walls, and still we are not tired of its magic. Today's architects can use glass as never before - for light, views and even to get around planning and building regulations; a glass balustrade, for example solves the problem of complying with requirements for the spacing of banisters and resulting "visual clutter", while an all-glass conservatory might be allowed in a conservation area where anything more solid would be considered inappropriate.

Structural uses of glass have resulted in ever more dramatic feats of transparency; glass lifts, glass floors and glass staircases. The Vancouver- based architects the Hulbert Group recently built a swimming pool with a transparent glass bottom suspended over a driveway between an apartment tower and a health club. The temptation to open the sunroof to gaze up at a watery sky full of flying people must be overwhelming.

While glass itself has become strong enough to be used structurally, there are now glues for bonding it which obviate the need for steel frames and bolts. Designer Thomas Heatherwick, who has just finished work on the new "Materials House" for the Science Museum, has a plan and a model for the first all-glass pedestrian bridge. "I'm a bit of an idealist," he confesses, "and I just thought it would be an amazing thing - like something from a fairy-tale." Developed with engineer Anthony Hunt, the structure uses new adhesives technology and is seamlessly transparent. To date, Heatherwick's glass bridge remains more fantasy than reality as no one has commissioned it.

Another architectural fantasy awaiting an adventurous client is an all- glass house designed by architects Allford Hall Monaghan Morris. Their "small weekend hideaway" exploits the limits of current glass technology with walls and ceilings entirely made of glass, and supported by glass beams. The problem of privacy is addressed by Privalite, a cutting-edge system which transforms glass from opaque to clear by passing a current through it. Heating is miraculously encased in transparent pads within the glass. Outer walls and the roof are photo-reactive. This is an impressively hi-tech design which, in their own poetic language "liberates the rooms from their imprisonment and rescues the garden from its status of feeble appendage" - in other words, minimises the barriers between the outdoors and the indoors.

On a smaller scale but no less romantic, Jeff Bell, of Glass Casts, has just seen his second glass staircase installed. The first was for Baggy House in Devon, probably the most famous modern house of the last decade, designed by Anthony Hudson. The latest is a double- height spiral for a house in Hampstead, London, "reorganised" by the architecture and design studio, Softroom. Glass Casts is well known for its ability to manipulate glass on a large scale. Another recent project was a glass bath, commissioned by the architect Matthew Priestman, cast as a seamless whole.

Some of the most futuristic uses of glass combine it with lighting, as in the Monte Carlo tower block apartment recently remodelled by Lazzarini and Pickering, where frosted glass panels are lit up and coloured by cinema gelatins to eery and beautiful effect. At this year's 100 Per Cent Design exhibition, Bobo will be showing furniture made from a revolutionary transparent plastic called Prismex. "It's screen printed with tiny, almost invisible prisms," Nick Gant explains. "When you illuminate it with a low energy bulb the prisms grab the light and spray it so you get a completely even glow - it's an incredible effect - cosmic." A science-fiction vision of luminous coffee tables and radiant chairs apparently levitating on glass floors springs to mind. The magic of glass persists.

Allford Hall Monaghan Morris, 0171-251 5261; Bobo, 01273 684753; Jeff Bell 0171-275 8481; Thomas Heatherwick 0171-485 3333; Hulbert Group (Vancouver), 0906 302 0400; Lazzarini Pickering (Rome), 0039 06 321 0305; Original Bathrooms, 0181-940 7554; Purves & Purves (for Starck chair), 0171-580 8223; Softroom, 0171-437 1550; New Designers, 0121-767 4787