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Scanning for Success: How Lasers Are Improving Construction Projects
Travis Fischer is the Virtual Design & Construction Manager for Kinsley Construction, Inc. He first joined Kinsley in 2012 with extensive experience in BIM for construction. He earned his degree in Architectural Technology from Thaddeus Stevens College of Technology and is a member of the Central Pennsylvania Revit Users group, and BIM Curriculum Development Team at Towson University where he is also an adjunct professor.
Early in my career, while working at a design-build mechanical contractor, one of my first tasks was to survey a small office building’s existing HVAC system. I headed to the job site with a laser tape measure and notepad to track the dimensions and location of the current ductwork, piping and equipment. In the moment, I remember questioning if I had captured everything correctly. Were there any critical existing conditions or systems that I was overlooking?
After entering the information into AutoCAD, I quickly realized that I was unable to capture all of the dimensions needed to complete the drawings for this space. This resulted in additional trips to the job site to gather what I hoped were accurate and complete dimensions.
Other industry professionals have shared similar stories with me over the years. Luckily, with the evolution of technology in construction, laser scanning now provides a more accurate and efficient way to gather needed information.
How it works
A laser scanner is a piece of equipment than can accurately capture the shape or condition of an object and convert it into a three-dimensional digital format known as a “point cloud.” Laser scanners work with the same principals of a range finder - they measure the distance between an object and the scanner by shooting a laser beam out to the object and recording how long it takes that laser to bounce back. By using speed of light to measure that time, the scanner can compute the distance and angles to the object. It’s ability to rotate on a tripod and shoot lasers to create millions of points in just a few minutes allows it to be a more efficient tool compared to the standard range finder.
Laser scanners work through line of sight only. They aren’t able to see through walls, so in order to capture all sides of an object or a large area, the scanner must be moved to multiple locations to gather all the information needed.
Use of GPS, “targets”, and software allow the individual scans to be stitched together to create 3D “point clouds”. These point clouds are made up of millions of points where the laser was shot and measured the distance to an object. These point cloud files can then be imported into software like Autodesk Revit to create an accurate 3D model for design and construction.
While laser scanning isn’t the newest construction technology to hit the market, its ability to capture dimensions within existing spaces and systems provides highly accurate as-built or survey conditions. It’s also a more cost-effective resource for project teams – allowing them to quickly gather job site information and avoid sending teams out with laser tape measures and notepads hoping to get it right on the first try.
Putting it to use
Recently, on a historic auditorium renovation project, laser scanning technologies were used to finalize the design. The renovation included demolishing the space down to the structure then rebuilding with completely new architectural layouts and MEP systems.
The laser was used to scan the large, open area and capture dimensions of the existing masonry walls and structural steel. The structure’s point cloud was used to design and coordinate all of the new work. With ceiling clouds, ductwork, lights, sprinklers, catwalks, stage lighting and equipment, there were thousands of hangers to attach to the existing structure.
Through laser scanning, the project team was able to locate hanger attachment points, which also allowed the subcontractor to layout his attachment points and prefabricate the ceiling clouds off site. This process helped led to a seamless field installation and kept the project on schedule.
Laser scanning directly impacts the quality and effectiveness of capturing a building’s existing conditions and creating proactive designs. Project teams are able to collect accurate information while saving time and money for the owners. This process is another example of how technology, large and small, will continue to alter how we complete day-to-day tasks on the job site and deliver construction projects.
