Abstract: Most of the existing three-dimensional (3D) modeling methods focus on geometric model construction, which neglect the semantic representation and multiple levels of detail, making the outcomes difficult for data interoperability. To address these issues, this paper proposed a set of 3D modeling techniques to generate geometric and semantic coherent building models on the basis of city geography markup language (CityGML), an open international standard for 3D virtual data storage and exchange. Geometry extrusion, semantic information extraction based on geometry features and rules, geometric and semantic mapping were explored for generating CityGML models with multiple levels of detail. A WebGL-based 3D GIS platform was developed utilizing the open-source Cesium library, and CityGML building models with four levels of detail were presented on the case study of campus area of the Hong Kong Polytechnic University. Experimental results indicate that the proposed modeling approach is able to make full use of the existing 2D building footprints, 3D geometric models, and building information models, and that the generated CityGML models with geometric, semantic, topological and appearance characteristics can provide better solutions for various applications such as 3D building model interoperability, data sharing, spatial analysis, and fine management. 

Key words: building, semantic modeling, CityGML, levels of detail, building information model