A metre rule, pen, notepad and a keen eye – you don’t need anything besides that to measure buildings or facilities. Or do you? As in many other areas of life, digitisation is also taking hold here.
For some years, 3D laser scanning has been revolutionising the ways things are documented and planned in archaeology, architecture and industry. The three-dimensional visualisation of buildings and complex shapes enables a more accurate, reliable and faster working method.
Laser scanners, as the name suggests, work with laser light. During a single scanning process, a short sequence of steps is carried out several million times: the scanner emits a laser beam, which is reflected by the surroundings. The scanner’s receiving optics pick the beam back up. The laser light received by the scanner is evaluated using special measuring procedures.
From the point cloud to the real image
The 3D laser scanner is fastened onto a tripod and rotates slowly around a vertical axis by means of a standard servomotor. A mirror, which rotates around its horizontal axis at several hundred revolutions a minute, deflects the emitted laser beam. In doing so, the laser scans all the surfaces surrounding it in a particular radius, records the intensity of the reflected signal and creates millions of tiny measuring points – up to 976,000 points per second. These measuring points result in an image of the surroundings in the form of a point cloud. The scanner links these points with photos of the real surroundings. The result is an image of the surfaces in three-dimensional space.
By means of so-called reference spheres, which act as orientation points for the scanner, several scans can be connected with each other to create a digital image, for instance of a complete floor of a building. Using a conventional CAD program, objects and designs can be added to the 3D images created by the scanner. This makes planning far easier.
Digital factory meets reality
Even the new construction of Festo’s Scharnhausen Technology Plant was planned with the help of an additive production method (3D printing). In a miniature factory, employees were able to get an initial impression of their future workplace whilst construction was still under way. When it came to modernising the electronics manufacturing, Festo opted for the 3D laser scanning. This enabled the future workstations to be planned quickly and, at the same time, in detail. Surprises after the planning phase, expensive adjustments and deadline extensions were avoided because the technical building systems were planned on the basis of real data, and missing dimensions were able to be determined quickly and easily.