Accurate measurements are a crucial element in the construction process, from design studies through final construction. This is especially true for historic buildings, where maintenance or renovation projects may rely on timeworn linen drawings, which may be incomplete or inaccurate.
Technological advancements mean facilities experts can document measurements assisted by computer-aided design (CAD) programs – saving us time and money, now and into the future.
In the past, measurements were typically taken with a tape measure, paper and pencil. The layout was pieced together from countless dimensions, photos, and experience. As projects evolved, multiple site visits were required to fill in information gaps. 3D laser scanning provides an efficient, technologically advanced way to quickly and accurately capture as-built conditions for building documentation.
While Facilities Services has employed 3D scanning on new construction projects and some renovation projects in recent years, FS fully embraced the benefits of 3D scanning in FY2014 by executing exterior and interior building scans of some of the oldest and most historically significant structures on campus. This project encompassed all 35 Main Quadrangle buildings, including such icons as the Harper Memorial Library and Rosenwald and Swift halls. Scanners captured exact images of 205 floors encompassing nearly 2 million square feet, according to Charles Maher, director, business applications & data management.
“Capturing accurate as-built data has long been challenging for building owners, architects, engineers and contractors. Due to the age of some University buildings, we often rely on record drawings to provide information on existing conditions, but it’s common for record drawings to be inaccurate or out-of-date,” Maher said. “3D scanning provides cross sectional views of floors from building to building, and exact sizes of structural members, angles and complicated dimensions that can easily be derived or modeled for planning or future renovations.”
Laser scanning is essentially the swift capture of three-dimensional information reflected from an object or surface to a light sensor. It creates a 3D construct called a point cloud made from multiple scans that have been unified through a process of registration.
Once the point cloud data is consolidated, traditional deliverables such as 2D plans, elevations, and sections can be readily extracted. The point cloud data can also be the foundation for 3D modeling, such as Building Information Modeling (BIM), saving many hours of digital model building.
“Our Operations team really benefits from these scans. Not only are the data available online, making it easy to access, it provides a virtual representation of building, floor and room space that shows visible attributes such as outlets, lighting, diffusers and so on,” Maher said. “This allows them to virtually be ‘in’ a space and ensure they have the right equipment on hand when performing maintenance and other tasks.”
Scanned data is visual, intuitive and immediately useful. While the raw scan data looks like a black and white photograph (shown at right), it is actually 3D geometric data that can be dimensioned and used to prepare CAD drawings and models, and thus ensure all construction and renovation projects at the University begin on solid and accurate footing.