A section of Rosslyn Chapel in Scotland, captured in minute detail with laser scanners. Credit Historic Scotland





Given a proposal for a new building in a city like Edinburgh, they can also create virtual realities, almost microscopically accurate, so viewers might see what the building looks like from all angles in the place where it’s intended to go, including the shadows it might cast at different times of day.

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The technology isn’t brand new or unique to Scotland, but the Glasgow team is on its cultural front line. Douglas Pritchard, a Canadian-born architect by training, is the wizard behind the Digital Design Studio at the art school. He heads the Scottish laser expedition with David Mitchell, director of Historic Scotland’s Technical Conservation Group. Describing how fast laser modeling has progressed and how far it might soon go, Mr. Pritchard said, “We’re no longer a million miles from the ‘Star Trek’ holodeck.”

He was perfectly serious.

The cultural implications of the technology are big, as are the political ones for Scotland, which, via the country’s culture minister, Michael Russell, has latched on to the laser team’s work.

It was about three years ago that Mr. Pritchard’s art school group began surveying a swath of the center of Glasgow, along the River Clyde, creating 3-D digital representations of some 1,400 buildings and dozens of streetscapes. They caught the attention of Mr. Mitchell, who enlisted Mr. Pritchard to scan a decaying iron bridge in Dundee, which was nearly impossible to survey with much accuracy except by laser. The bridge project led to scans of Stirling Castle and Rosslyn Chapel, the 15th-century Gothic fancy to which “The Da Vinci Code” has lately brought swarms of conspiracy-minded tourists. One of them was a man who tried one day to take a sledgehammer to the so-called Apprentice Pillar, convinced that the Holy Grail was hidden inside it.

No harm done, but the event illustrated, as Mr. Mitchell noted, why scans are necessary. “Remember Windsor?” he asked, referring to the fire in 1992 that burned parts of the British royal castle. “If restorers had had laser scans back then, they could have rebuilt everything to within three millimeters of accuracy, but instead they had to rely on conjecture from photographs.” He noted the more recent case of the Buddhas in Afghanistan that the Taliban blew up in 2001.

The basic principle behind the laser technology is simple: A box, with a laser inside, sits on a tripod; as the box slowly rotates 360 degrees, the laser, moving up and down, bounces its beam off whatever is solid in front of it. In so doing, it registers some 50,000 points in space every second. Traditional surveyors might produce a couple of hundred measurements a day, prone to subjectivity and human error. Lasers collect millions of measurements per hour. A scanner can even identify certain materials, determining whether something is, say, made of glass or stone.

Aerial lasers and a hand-held version operate the same way. Combined, they can bring to life as 3-D images entire cities or a mountainside, like Mount Rushmore’s.

This spring, at a digital-documentation conference in Glasgow, Mr. Russell met with Ben Kacyra, the American engineer and inventor of the scanner. Partly because of what had happened to the Buddhas in Afghanistan, Mr. Kacyra had established the nonprofit CyArk to compile scans of 500 Unesco World Heritage sites around the globe.

The Scottish crew was signed up to scan for CyArk five Scottish World Heritage sites (the Old and New Towns of Edinburgh; Neolithic Orkney; the island of St. Kilda; New Lanark; and the Antonine Wall, an ancient Roman ruin) as well as five other sites. Having been already in touch with the Park Service about Mount Rushmore, CyArk enlisted the team to start there.

What are the big cultural implications? For starters, Mr. Pritchard talked about “a new kind of empowerment.” He was referring to the prospect of using virtual-reality models to allow the public to judge all sorts of proposed urban plans. The drawings and computer simulations long cooked up by developers and architects will be replaced by more detailed, easier-to-comprehend, more objective views, in essence democratizing knowledge.

The benefits of storing and distributing state-of-the-art views of the world’s most precious cultural sites at low cost (the annual budget for the Scottish team is under a half-million dollars) are obvious.

By way of example Mr. Pritchard showed off on his laptop a ruined Victorian monument, Paisley Fountain. It was returned in virtual guise to its original lacquered green sheen, thanks to some paint scraping taken by Scottish restorers. When combined with the laser scans, the scrapings proved what the surface of the fountain first looked like. Nobody had imagined it to have been so shiny. “But,” as Mr. Pritchard said, “technology doesn’t lie.”

Then he clicked on a virtual model of a Maori canoe, bought in pieces not long ago by the National Museum of Scotland and never assembled. Laser scans proved it never could be: the pieces turned out not to belong together.

The demonstration pointed toward some bright, gleaming, globalized frontier of cultural information-sharing and progress, albeit curiously backward-glancing. In London at the moment there happens to be an exhibition of paintings by the German-born British artist Frank Auerbach from the 1950s and early ’60s, marvelous pictures that show the city rebuilding as if from scratch after the war.

Back then, death and destruction held out for midcentury Modernists the prospect of a new urbanism, a fresh start born of loss and industrial advances.

That was half a century ago.

The new cutting edge of laser technology offers instead a means to preserve and restore whole cities exactly as they once were. It promises a world kept as if in amber.

A virtual past that never dies.

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