London heritage properties marked for demolition digitally preserved by city

A growing number of heritage buildings primed for demolition in London will live on virtually with the help of high-end 3D technology.

The city has amassed a small but growing number of virtual building replicas as part of its regular process to document and photograph heritage properties, or properties with heritage components, before their date with the wrecking ball.

Three buildings have already been documented this way and two are on their way. They include two properties along Wellington Road near Grand Avenue where work is being done on the southern leg of the city's bus rapid transit network. 

16 Wellington Rd., a one-storey Art Moderne-style building built in 1946, is set to be demolished, while 28 Wellington Rd., a storey-and-a-half Queen Anne-style home constructed in 1906, was levelled earlier this year, along with two identical homes on either side of it.

Both were documented last year at the request of the city by the London-based firm SkyDeploy, which used drone photogrammetry and LiDAR scans, or light detection and ranging, to create detailed 3D duplicates which can be moved and viewed close up in virtual space.

"I don't think there's a lot of awareness about the capabilities and how straightforward this is. It may seem very daunting and expensive and out of reach, but it's really become a commodity," said Ted Strazimiri, who founded SkyDeploy in 2017.

The city had tapped SkyDeploy to inspect some buildings using drones, including the London Normal School, Strazimiri said. A 3D model he produced out of the data piqued the city's interest in the technology.

For the city, the appeal is the accuracy, speed, and cost-effectiveness, said Kyle Gonyou, the city's manager of heritage and urban design. Along with the 3D model, the process can also spit out a 2D technical drawing of a property's elevation.

"We're finding that it's at a high degree of detail, which provides a really great resource and record of the buildings prior to their demolition," he said.

"We're still trying to explore the opportunities that this kind of digital documentation produces."

Photogrammetry and LiDAR aren't new, but the technology has advanced rapidly over the last decade thanks to drones, higher-resolution cameras, more advanced software, and increasing computer power.

The goal is to create an extremely detailed 3D model, something which requires a significant number of photographs — upwards of 3,000 — covering every angle of the building, Strazimiri said.

Technology has improved to the point where all Strazimiri has to do is give the drone an area in space and tell it to scan what it finds, he said.

"The drone intelligently will pick up all of those surfaces, understand what the shape of that structure is, and fly around it taking pictures," he said. The images are mapped onto a 3D model the drone creates.