Journal of Geo-information Science >
Hybrid Modeling for Urban Buildings Based on Textures and SCSG-BRs Representation
Received date: 2017-11-30
Request revised date: 2018-02-09
Online published: 2018-04-20
Supported by
National Natural Science Foundation of China, No.41431179
Guangxi Natural Science Foundation, No.2015GXNSFDA139032.
Copyright
With the complexity of and the photorealistic requirement for urban buildings in rapid development of urbanization, the high accuracy of modeling for 3D urban buildings and the establishment of an effective data structure for those complicated building becomes a challenging work. With consideration of the shortage of the current CSG (Constructive Solid Geometry) modeling, this paper presents a hybrid modeling, which combines CSG and BR (Boundary Representation). In the proposed model, the traditional CSG model is improved by what is known as "Spatial CSG (SCSG)", which uses the dimensionally extended Nine-Intersection model (DE-9IM) to represent the topological relations between voxels and determines the unique SCSG tree to represent the exterior shape of the buildings. And then, the BR is used to represent the topological relationship between geometric elements of the urban buildings, which considers the texture as the attribute data of the wall and the top and combines SCSG as SCSG-BR method. This proposed method combines the file database and the relational database to manage the data of three-dimensional (3D) buildings. The attribute information of the building model and the texture are stored in the relational database. The file database contains a model file and a texture image file, which are used to store the building and the texture image. The texture images are separately stored in another relational database by a variable-length binary data type. During the storage and recall of texture images, the urban building model ID and the texture ID are linked through face ID in relational database. The texture images and the urban building model are loaded and stored at the same time. Thus, the management method has less complex processes in texture mapping and improves the model loading speed. In the data processing, the least squares algorithm is used to normalize the building polygons, and adjust the polygon topology to ensure the accuracy of the modeled data. Data sets, located in Denver, Colorado, USA, and Zurich, Switzerland, are selected to validate our method. The time-consuming comparison of model loading using the different modeling methods are conducted, and the experimental results demonstrated that our method consumes least time out of all methods. The experimental results also demonstrated that the hybrid modeling method proposed in this paper can not only accurately represent the topological relations of the building entities, but also quickly load the building texture images, which is capable to achieve fast and accurate modeling buildings, and effectively realize spatial query.
Key words: urban; three-dimensional modeling; building; CSG; BR
ZHOU Guoqing , HUANG Yu , YUE Tao , WANG Haoyu , HE Chaoshuang , LI Xiaozhu . Hybrid Modeling for Urban Buildings Based on Textures and SCSG-BRs Representation[J]. Journal of Geo-information Science, 2018 , 20(4) : 543 -551 . DOI: 10.12082/dqxxkx.2018.170574
Fig. 1 The description of SCSG representation图1 SCSG表示的描述 |
Fig. 2 The data organization of urban building model图2 城市建筑物模型的数据组织 |
Fig. 3 The storage method of urban buildings图3 城市建筑物数据存储方法 |
Fig. 4 The relationships of urban building models in the relational database图4 关系数据库中城市建筑物模型的关系 |
Fig. 6 The result of building polygon orthogonalized and the adjusted building polygon topology图6 建筑物多边形正交化和拓扑调整 |
Fig. 7 The construction demonstration of simple buildings图7 简单建筑物的构建 |
Fig. 8 Formation of the complicated buildings图8 复杂建筑物的形成 |
Fig. 9 Modelling the complicated buildings图9 复杂建筑物建模 |
Fig. 10 Three-dimensional urban building model represented by SCSG-BR图10 空间CSG-BR表示的城市三维建筑物模型 |
Fig. 11 The comparison analysis of three different types of methods for modeling urban buildings图11 3种不同城市建筑物建模方法的比较分析 |
Tab. 1 Time-consuming comparisons of four different types of modeling methods表1 4种不同类型建模方法模型加载耗时比较 |
建模方法 | 加载模型耗时 | 平均耗时 | 说明 |
---|---|---|---|
SCSG-BR混合建模方法 | 3.56″、3.44″、3.68″、3.57″、3.65″、3.6″、3.57″、3.55″、3.61″、3.43″ | 3.57″ | 包含真实纹理 |
Arc Scene建模 | 2.56″、2.40″、2.76″、2.72″、2.69″、2.78″、2.77″、2.76″、2.68″、2.75″ | 2.69″ | 无纹理 |
CAD建模 | 6.48″、6.23″、6.36″、6.38″、6.44″、6.23″、6.27″、6.28″、6.24″、6.38″ | 6.33″ | 无纹理 |
3Ds MAX建模 | 3.92″、3.63″、3.99″、3.77″、4.04″、3.66″、3.71″、3.70″、3.93″、4.06″ | 3.84″ | 包含真实纹理 |
The authors have declared that no competing interests exist.
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