Creating Topologically Consistent 3D City Models of LOD+ with Extrusion

There are many methods to create 3D city model, in which the simplest one is to extrude building footprints to obtain “block-shaped” polyhedra representing buildings. While the resulting 3D city models are not topologically consistent, if the 2D topological relationships between the footprints are not taken into account. As a result, the created models only meet the purpose of visualization. In this paper, we focus on creating topologically consistent 3D city models from the footprints of heterogeneous structure buildings. The generated models are more detailed than LOD1 of CityGML and are called LOD1+, which not only construct topology between buildings but also generate internal structure topology of them. We have implemented the procedure, tested it with real-world datasets, and validated it.