Real-time Generation And Rendering Of Urban Buildings Based On Sweep Surfaces

An urban city is generally built-up with drastically different patterns of buildings due to influence of varied landscapes. Creating 3D buildings is not only a main task of city modeling but also the basis of 3D city visualization. Modeling of large-scale urban buildings usually requires a significant amount of manual work and consumes a lot of time.We introduce sweep surface assemblies to represent a 3D building in this paper. Superformulae and polylines are employed to describe the contour of sweep surfaces in order to capture all kinds of building shapes. Based on the representation, each bulding can be easily instanced according to its footprint curve and profile transformation. We also investigate an adaptive GPU tessellation approach to rendering of building surfaces.To make buildings approximate architectures in real world, we exploit a method to create contours and profiles of buildings from real data: extracting footprints from GIS data and from grammars of procedural modeling, and extracting profiles from the design section of buildings.To generate building details such as doors, windows and eaves, we propose sampling distance mapping as an improvement of distance mapping so as to reduce memory comsuption considerably.The proposed framework can achieve real-time rendering rate of urban buildings in a heavily built-up city while maintaining high quality and providing per pixel detail rendering of buildings. Experimental results on a NVIDIA GT 130M mobile GPU machine show its feasibility and flexibility.