A construction research group is throwing away its 3D virtual reality goggles and putting on 2.5D 'multimedia hard-hats', writes Keith Devlin
Retreat from reality
Virtual reality may be too real for the construction industry. Until now, the accepted wisdom has been that expensive cock-ups on construction sites can be best avoided by simulating the entire process beforehand on a 25,000 Silicon Graphics workstation. But according to David Leevers, project manager of the Collaborative Integrated Communications for Construction initiative, more practical benefits are likely to come from what he calls "augmented reality".

CICC was set up in September 1995 with three years' funding from the European Community to investigate the uses of new technology in reducing spiralling costs in the construction industry - with the aim of saving up to 30 per cent.

Leevers, who is also manager of multimedia communications for the BICC Construction Group, believes the answer is not 3D immersion but 2.5D theatre. Instead of the 3D goggles of VR, Leevers prefers a "multimedia hard-hat" fitted with earphones, microphone and computer, its display visible out of one eye, to the side of the field of vision.

From a cognitive point of view, we don't really live in a 3D world at all, says Leevers, but rather in a "2.5D world", a term invented by vision expert David Marr to describe the mental image we produce in our minds from the two 2-D images provided by our eyes.

"We are so swamped by the immediacy of visible surfaces that we are more comfortable treating the world as a 2.5D panorama," Leevers explains. "Our binocular vision does little more than build a private z-axis buffer."

"Thus 3D VR may be preserving one of the most inconvenient aspects of the real world, the fact that bodies take up space and prevent everyone seeing the world from the same point of view."

To emphasise his point, Leevers asks us to think of a standard theatre stage. "The 2.5D stage with its simplified layers of scenery has more dramatic impact than the 3D 'theatre in the round'. True immersion is best when limited to brief dramatic moments - the actor bursting from the audience or the thunderous opening to Star Wars."

Talking to Leevers, you are never sure whether you are talking to a hard-headed businessman or a futuristic technothinker. His far-reaching vision of the future appears to be matched equally by the firmness with which his feet are placed in the muddy ground of the real construction site.

"My own interest in virtual reality was not from a need to simulate a real environment, but to resolve the problem of fitting increasingly rich telecommunications services into day-to-day activities in manufacturing and construction," he says. "Because these group activities deal with 3D spatial problems, they can be expected to be a ready market for collaborative virtual environments."

He argues that by using modern multimedia communications technologies, widely scattered teams can keep in close contact without the expense of jetting people around the globe. And increasingly the overall cost of modern construction projects is dominated by the money spent on managing the information, rather than on the steel and concrete. More efficient information management means more efficient construction.

[For details on the CICC project, consult CICC. David Leevers is due to speak at the Virtual Environments on Internet, WWW and Networks conference in Bradford, April 14-17. Details from r.a.earnshaw@bradford.ac.uk]

26 March 1997