A 3D building model displays the surface of a building digitally in a three-dimensional space. For creating a 3D building model, a building is measured with a 3D laser measuring system, e. g. a laser scanner, from several positions. The scan data (point clouds) are merged into an overall point cloud in a software. Afterwards, a three-dimensional model of the scanned building is generated in a CAD software. Over the past years, the usage of a special BIM software has gained in importance more and more. In contrast to a pure 3D CAD model with interfering edges, the BIM system also saves technical data. Thus, BIM (Building Information Modeling System) can be used for the building's management (life cycle management). The 3D building model describes the actual state of the building at the time of the scan recordings.
More information: 3D documentation