建筑物BIM与实景三维模型融合方法研究

建筑物BIM和实景三维模型分别是建筑和地理信息领域两种三维模型，二者融合后的模型除了可展示建筑物自身内部细节，还可以分析建筑物与周边环境的相互作用，为智慧城市相关领域中的应用提供基础与支撑。二者融合的难点表现在建筑物几何信息融合、建筑物子组件语义信息的整合，以及空间位置的配准等方面。设计了二者融合的框架，选取IFC模型作为融合前的源模型，3DTitles作为融合后的目标模型，论述了融合流程和方法，包括：1） 重构BIM模型，根据建筑物构建类型，重构成子BIM模型； 2） 模型几何信息转换，采用中间交换格式法，选取obj和glTF格式实现交换； 3） 模型空间位置配准，先选取不同模型建筑物上的同名点，然后采用SVD算法计算配准参数完成配准； 4） 子组件语义信息映射，根据实景三维模型文件格式要求重新组织建筑物构建的语义信息。选取南京市某楼群开展了实验，验证了该融合方法，展示了此楼群BIM模型和实景三维模型的融合结果。总体上所论述的融合方法，除了可实现建筑物BIM与实景三维模型语义、几何和位置融合，在操作上除了需要手工选取同名点配准外，其他步骤均可通过程序自动实现，从而快速建立室内外一体化的建筑物模型。

Research on fusion method of building BIM and reality 3 D model

Building information model (BIM) and reality 3D model are two kinds of building models in civil engineering and geographic information fields, respectively. The merged model may not only be used to present the detailed information of inner building, but also to analyze the interaction between building and the around environment, which can provide good support to the application in different fields of the smart city. The difficulties of the fusion are building geometric information fusion, semantic integration of sub-components of building and spatial position registration. For this, the framework of fusion was described in which the IFC model was selected as the source model and 3DTitles model as the target model. The workflow and method of the fusion were discussed, including reconstruction of BIM model according to building components, geometric information transformation of the model using interchange format obj and glTF, spatial position registration according to the tie-points and SVD algorithm, and semantic mapping of building components regrading to the format of the reality 3D model. Finally, experiment on buildings of a company is engaged to verify the proposed fusion method and display the fusion results. Overall, the method discussed in the paper is able to realize the fusion of BIM model and the corresponding reality 3D model in perspective of semantics, geometry, and location. Meantime, the method can automatically realize the fusion steps except select registration tie-points, so as to quickly build an integrated indoor and outdoor building model.