What are As-Builts and what do they have to do with point clouds? Let's explore the different options in creating As-builts and how new technologies can advance workflows and minimize errors.
An As-built is a documentation of an existing building. This can include floor plans, elevations and cut sections of a building. All you need to create an As built is a tape measure, a pen and a piece of paper. This is the method in which As builts were created for a long time and in theory it works just fine. Although this method may seem simple there are many problems that can come up and errors that can occur. First and foremost, the original method is extremely time consuming. Each measurement must be taken individually and immediately documented. In addition, there are some measurements that are impossible to capture such as some wall thicknesses. Since even in a small building there are hundreds of measurements taken, there is a large room for errors.
Recently many As Built providers have been adapting to the use of 3D laser scanners. A laser scanner is a sophisticated piece of technology that can capture millions of measurements throughout a scan of a building. During a scan, the scanner emits laser beams in all directions. When one of these laser beams hits an object, it returns to the sensor. Leveraging the speed of light the scanner processes the distance of the object. The process is repeated millions of times throughout a scan. Using advanced software the data is processed, creating a complete 3d model of the scanned area. This model is called a point cloud- a cloud of points forming a model.
This scan is imported into a CAD (Computer Aided Design) software where the point cloud is traced by a drafter. The drafter adds walls, windows, doors, staircases, and roofs to complete a plan of the building. Now there is a full floorplan of the entire building ready to be exported into any format needed.
This workflow has many advantages. Primarily, everything in the building is documented. There is never a need to revisit a location because the scanner captures everything it sees. For example, at a later stage of a project an architect may need to know a soffit height. All he needs to do is pull up the scan and measure on his computer the height, length and width of the soffit. Another major advantage is the efficiency of laser scanning. A complete house can be scanned in half an hour. Massive commercial spaces can be scanned completely and accurately in several hours. This would be impossible using traditional methods.
The construction industry is continuously advancing in technology. New laser scanning machines and software are constantly expanding the possibilities of capturing space.
