Laser scanning and 360° photo documentation are two technologies that provide builders, engineers, and architects with the ability to capture the specific details of as-built projects.
Their use cases, however, differ markedly, according to Nicolas Arnold of software firm HoloBuilder, which makes applications for 360° photography.
Laser scanning, specifically terrestrial laser scanning, can be used for a variety of functions that demand extreme precision, but at a high cost and with high complexity.
“When you want to capture a structure with high precision, or if you want to measure something, you use a laser scanner,” Arnold said, adding that some scanners offer accuracy down to two to three millimeters.
Laser scanners create a detailed three-dimensional model of a structure called a “point cloud.” The point cloud can have thousands and even millions of points, so it’s data intensive. Creating the point cloud can be labor intensive for complex structures, and therefore costly, Arnold said.
Laser scanning is ideal for creating a 3D model of an existing structure, such as power plants, stadiums, and other complex structures.
“If you want to reconstruct the model from reality, especially for an existing plant where there's a lot of pipes and other objects, for example, you want to start with a with a good laser scan," Arnold said. "Then you process that data with software and you get a 3D or BIM model out of that.”
The scanners can be combined with drones, as well, to capture data that would be difficult to capture in any other way, for instance if you're looking to generate a model of an existing bridge with hard-to-reach areas.
Another use case for laser scanning is comparing the as-built structure with the model created prior to construction.
“It's basically comparing a point cloud to models to see with what precision you have actually built based on the model that was used to build,” Arnold said.
Complex structures require multiple scans to “see” all rooms and spaces, as scanners can’t “see” through walls. Those scans create multiple point clouds that must be combined into a unified whole.
All that precision comes at a price. Scanners from Leica and Faro sell for $15,000 US and up. High-end scanners from Reigl, used for civil projects, cost $150,000 or more. The massive amounts of data generated in scanning must also be stored. That level of cost makes laser scanning out of reach for smaller firms.
Photo documentation with a 360° camera does not offer the same level of precision as laser scanning, Arnold said, but it’s fast, cheap, and easy.
“360° photos are good when you want to have a holistic view of your project,” he added. “You don't want to do close-ups, you just want to get an overall impression of the space.”
Because they capture everything within a space, 360° photos are used for documenting as-built projects during the construction process.
“You know after the fact how or what was built so that you don't have to tear off the drywall to see where the plumbing and electrical are located,” Arnold said.
For greater detail, 360° photos can be combined with standard photos, or “flat” photos, Arnold said, with the flat photos offering close-up views of specific details.
The cost for an entire kit is minimal. One popular camera, the Ricoh Theta S, sells for about $300. A tripod and mobile device complete the kit, plus any cost for the software that can help with organisation of the 360° photos.
360° photo documentation is user friendly, as well.
“When you take a 360° picture, you just take the camera out of your pocket,” Arnold said. “Maybe you put it on a tripod and you take a picture and you're done.”