Automatic Reconstruction of Roof Overhangs for 3D City Models.

Most current 3D city models, created automatically from cadastral and remote sensing data and represented in CityGML, do not include roof overhangs, although these overhangs are very characteristic for the appearance of buildings. This paper describes an algorithm that procedurally adds such overhangs. When a CityGML model is textured, the size of the overhangs is determined by recognizing overhangs in facade textures. In this case, the method only needs an already existing model in CityGML representation. Alternatively, if an additional point cloud (e.g., from airborne laser scanning) is available, this cloud can be utilized to calculate the overhang sizes. We compare the results of both methods.