The Boston Public Library is using three-dimensional laser scans in its $16 million renovation project on Boylston Street. At Mystic Seaport, such scans have been crucial in caring for a historic whaling ship. And 3-D images revealed a 300-year-old staircase within the walls of the Old State House downtown.
About five years ago, Feldman Land Surveyors, of Boston, embarked on a pro bono campaign to render 3-D images of historic sites such as the Paul Revere House in the North End, the Clapp Family Barn in Dorchester, and the African Meeting House on Beacon Hill. The initial idea was simply to create nifty images.
“When you combine technology and history, people get excited,” said Michael Feldman, the firm’s president. “We have so many historic buildings in Boston. We should be recording them.”
But the images have also become a useful tool for preservationists seeking minutely detailed renderings of historic properties. While the scans are an excellent way to document sites for posterity, experts say, they’ve also been helpful in millions of dollars’ worth of renovation work in New England and beyond.
“I think of how many historic vessels I’ve seen vanish in my career,” said Quentin Snediker, director of the shipyard at Mystic Seaport in Connecticut, where he oversees repairs and maintenance of hundreds of vintage tall ships and sea craft. “If this stuff was available 20, 30 years ago to quickly record the details of a ship that is now completely gone, it would have been a great boon to historic preservation.”
The renderings have also been good for Feldman’s business. The Boston Public Library and other institutions have paid for additional images since Feldman recorded parts of their buildings for free. “I knew on a business level it would be good,” he said.
After Feldman scanned the outside of the library’s iconic, late 19th century building facing Copley Square, officials decided they wanted a more extensive rendering of a modern addition, designed by the famed architect Philip Johnson, that opened in 1972.
Crews began a series of repairs and renovations to the addition in December.
“In terms of visualizing some possibilities, looking at concerns, and identifying areas of possible conflict, it’s much easier for the layman to see in 3-D than two-dimensional diagrams,” said David Leonard, who is overseeing the work as the library’s director of administration and technology.
Three-dimensional scans helped Leonard and others determine whether new corners inside the revamped Johnson addition would be too sharp and jarring for people walking through the building.
“It’s a mundane and practical example, but it’s very important when you are thinking not only about how it will look but also how it will be used by patrons and by staff,” Leonard said.
Created by lasers that record nearly every nook and cranny on surfaces within a quarter-inch of accuracy, the scans are commonly used in industrial engineering and other fields, Feldman said. “It’s really a measurement device,” he said.
For preservationists, the scans have proved to be crucial because they measure historic buildings, boats, and other items without touching or harming fragile materials. They record the settling, sagging, and other changes wrought by time on sensitive structures.
The Bostonian Society, which manages the Old State House, used Feldman’s three-dimensional scans to determine how the 1713 building shifted over the centuries — in part because an MBTA station was housed in the basement — as the group completed $3.5 million in renovations.
“It looks symmetrical but it’s not,” said Brian LeMay, the society’s executive director. “We needed detailed information about the dimensions of the building.”
Because the laser scans use light rather than a tape measure or any similar device, Feldman’s surveyors were able to insert scanners into holes and crevices to look within the building’s walls, ceilings, and floors that had been layered upon each other over many years. They discovered the remnants of an original staircase once used by British governors and their staffs.
“We thought it would be mostly useful to us as a PR device,” LeMay said. “We could put it on our website and show people how neat the building looks. But it actually proved useful with doing restoration work.’’
Such images were instrumental in the Mystic Seaport’s restoration of the Charles W. Morgan, an 1841 whaling ship that scheduled to dock in Boston Harbor on a tour this spring, Snediker said.
Feldman scanned the ship before and after restorers pulled apart the vessel, giving them a map for a complicated and perilous job.
“In the restoration process, it’s kind of an archeological investigation. You are destroying it as you are restoring it,” Snediker said.
As an added benefit, the 3-D images provide an archive for future scholars, he said.
The Charles W. Morgan is the oldest operating commercial wooden ship in the country.
“A wooden vessel of this type is a dynamic structure,” Snediker said. “It changes over time. What this scanning will do is help us monitor those changes over time in a much more precise way [than] we could with hand measures. Should disaster befall her, it’s recorded for posterity.”
Feldman hopes to bring together all of his scans into a database that might serve as an educational tool.
“We want some kind of mobile app where you can see historic Boston, whether it’s the Freedom Trail or other parts of the city,” he said.
He also hopes to partner with CyArk, a nonprofit in Oakland, Calif., that wants to render three-dimensional images of historic sites around the globe.
Motivated by the Taliban’s destruction of 1,600-year-old Buddhist statues in Afghanistan, the group has scanned temples in Angkor Wat, the statues of Easter Island, and other famous landmarks, according to its website.
Feldman said most of his work on historic sites has come from local, informal connections. He hopes CyArk can help him work in other regions and identify ways to pay for more ambitious scans.
“It would cost a lot of money to go and do the pyramids,” he said.