Study of an SCSG-OSM for the Creation of an Urban Three-Dimensional Building

With the increasing needs of and rapid developments in digital and/or smart cities, an effective method for the management of various types of complex and massive buildings for the creation of a three-dimensional (3D) photorealistic city has become crucial for high-quality “digital/smart city” construction. To this end, this paper proposes a data model called the “SCSG-OSM”, which combines spatial constructive solid geometry (SCSG) and the object-based spatial model (OSM). The SCSG-OSM assumes an object can be represented by four element types: point, line, face and body. The SCSG applies an extension of the dimensionally extended nine-intersection model (DE-9IM) to describe the spatial topological relationship. The OSM consists of nine definitions that define the points, lines, faces, and bodies of an object and applies point sets instead of node sets and face sets instead of surface sets to model buildings. Two data sets, depicting Denver, Colorado, USA, and Zurich, Switzerland, are employed to assess the storage space and the time consumption averages during the modelling of 3D buildings using the proposed data model. The experimental results demonstrate that the proposed SCSG-OSM is able to save storage space and reduce the computational time compared with the CSG-BR model, TIN model, POLYGON model, Patch model, SSM and CityGML model. Therefore, it can be concluded that the method proposed in this paper is a simple and effective method for the 3D photorealistic visualization of a large city.