A 3-D laser scanner—a line-of-sight device that uses light detection and ranging (LIDAR) technology—has become a necessity for contractors, architects, engineers and surveyors that want to stay ahead of the competition. 

Old school methods of measurement, such as a plumb bob and a measuring tape, often resulted in incorrect or inaccurate measurement documentation due to human error. Hand-measuring a commercial building could take weeks or even months, and it often involves multiple trips to the site, costing the client significant money due to increased labor hours and rework.

With efficient 3-D laser scanning technology, a time-of-flight 3-D scanner can capture millions of measurable data points in a matter of seconds within 4 millimeter accuracy at a distance of 300 meters. The “point cloud” of measurable data points can be imported easily into various AutoCAD software programs for use with BIM systems.

BIM Integration
BIM provides a digital layout of the real-world conditions that existed at the time of the scan. Using the BIM process, additional scans can be completed and tied back into the existing project to provide as-built data throughout the life cycle of a project. This allows construction layout points to be added from the point cloud to the BIM model as well.

Industry-Wide LIDAR Applications
Some AEC firms may feel like they are lagging behind by not getting on board with 3-D laser scanning before now, but that is simply not the case. Although LIDAR technology has been around since the 1960s, it did not become widely utilized by the construction industry until the last 10 years or so. 

Applications and uses for the construction industry are endless. Architects and engineers find working virtually with accurate measurable data is a huge benefit when they create their BIM model or drawings. Mechanical, electrical and plumbing contractors utilize the 3-D scanning technology to assist with spatial planning and clash detection. Surveyors use 3-D scanning to map topography and assist with calculating takeoffs. Having the ability to set the 3-D scanner and targets over a known control point makes it easier to validate changes in topography or various phases of construction over time.

Contractors, such as curtain-wall fabricators for high-rise buildings, have found 3-D laser scanning to be safer and more efficient. In the past, a laborer took measurements by leaning out of a high-rise window to measure the return of each window on each floor. This process was not only time-consuming, but also dangerous. Now, each window can be accurately measured within the software, and the materials can be prefabricated in the shop instead of onsite.

In the public sector, the U.S. General Services Administration (GSA) is encouraging the use of 3-D laser scanning on all government projects to assist with historical documentation of government buildings where blueprints are either unavailable or don’t match the existing conditions. GSA is currently requiring 3-D scanning for spatial program validation of all major renovation projects, as well as for design of new construction. For more information, visit gsa.gov/portal/content/102282.

Non-Invasive Scans for Historical Buildings
Blueprints can be created from 3-D scan data, making scanning of historic structures essential. The non-invasive, accurate documentation of these structures also historically archives the measurable data, which can be used in the event the structure is damaged or destroyed and needs to be recreated.                  

The “as-builts” that are captured by the 3-D laser scanner can be compared to the “as-designed” models to accurately identify any deviations or clashes between the design and reality. By integrating 3-D scan data into BIM, all team members can collaborate virtually when a difference of interpretation occurs. Any changes that are made to one component automatically update the other components at the same time, which greatly reduces costly coordination issues with future phases of construction. 

It can be difficult to see beyond the initial cost of using 3-D scanning; however, the return on investment is significant considering the total cost reduction due to fewer errors per job. As anyone in business knows, accuracy plus speed equals predictability, which in turn means increased profitability. 

3-D scanning allows the project manager to predict costs accurately during the bidding process, which ultimately reduces the total cost of the job due to a reduction in labor hours, rework and the total time to complete the project.

While the capital expense of purchasing 3-D scanning equipment and related software and training seems high initially,  contractors can form allegiances with companies that specialize in this technology to find cost-effective ways to begin using 3-D-to-BIM scans for their next project. 

Mary Anne Reuschling is president of TransCon Imaging Solutions. For more information, visit www.transconimagingsolutions.com.

Project Virtual

Members of Associated Builders and Contractors (ABC) can take advantage of affordable BIM training and products through Project Virtual, which has tools for contractors of every size and level of BIM sophistication. ABC members can test their BIM expertise with the Project Virtual assessment, or take advantage of exclusive discounts on Autodesk Design Suite licenses and subscriptions. Also, keep an eye out for BIMShare, a cost-effective way to bring construction partners together without making a significant investment in software. For more information, visit www.abcprojectvirtual.com.