# OpenBIM: An Enabling Solution for Information Interoperability
## 4 Engineering Information Interoperability Research Supported by OpenBIM
### Information Integration  
Information integration means that the information of the subsystems and users in the system uses unified standards, specifications and codes to realize the information sharing of the whole system, and then the interaction can be realized. openBIM provides a general standard of data exchange in this process. * BIM-based workflow  
It is evident that there is a pressing need for the standardization and uniformity of modelling. A well-defined workflow based on BIM can exploit and extend openBIM standard to improve information integration. Under this circumstance, [PERSON] et al. described the significant elements of an integrated BIM-based workflow, explained that openBIM comprised a standardized file format and stated what can be achieved with the help of the already available technology named IDM and MVD. Python language and open source IfcOpenShell were used in case study to illustrate the benefits of this workflow [73]. * Integration of BIM and geographic information system (GIS)  
In recent years, the integrated application of BIM and GIS is gaining more and more attention. The method of realizing information interaction through simple model conversion in different fields makes only a small amount of semantic information retained, which leads to the dispersion and independence of the application. IFC and CityGML are the common data model standards of BIM and GIS respectively, and the geometric and semantic information sharing will lay the foundation for the integration of BIM and GIS. For example, in order to import semantic IFC data into the GIS environment, [PERSON] et al. described the development of CityGML extension called GeoBIM, which is mainly the development and the implementation of GeoBIM extension for IFC data on CityGML, thus facilitated the integration of BIM and GIS [74]. To achieve Neighborhood Scale Modelling, [PERSON] et al. focused on ways of exchanging information and bringing together CityGML and IFC. The transformation system was developed using Feature Manipulation Engine (FME) by Safe Software. With the help of FME, data model (IFC) can be restructured and transformed to the destination data format (CityGML). The test results showed that CityGML format, as well as a Sketchup file, could be generated from detailed BIM models. These models can be imported to web visualization applications for urban energy modeling [75]. [PERSON] et al. reviewed the development and difference of BIM and GIS, the existing integration methods, and discussed their potential in many applications. The author pointed out that semantic web technology provided a promising generalized integration solution and openness was the key factor to the integration of BIM and GIS [76]. [PERSON] et al. described a new method of data integration based on the unified building model (UBM), which not only encapsulated CityGML and IFC models,  
Figure 14: openBIM for information extension. but also avoided the translations between the models and information loss. The case scenario and four queries have verified that the developed UBM can integrate CityGML data and IFC data in a seamless manner [77]. [PERSON] et al. reviewed relevant research papers to (1) determine the most relevant data modellings used in BIM/GIS integration; (2) look for the possibility of other data modellings which can be used for data-level integration; and (3) provide guidance for future's BIM/GIS data integration [78]. In order to solve the problem of integration of BIM and GIS heterogeneous models, [PERSON] et al. defined the integration process of BIM-GIS through the BIM-GIS conceptual mapping (B2 GM) standard and proposed a mapping mechanism related to it. Based on IFC and CityGML, the schema structure of BIM and GIS were analyzed from the perspective of BIM-GIS integration. In addition, the IFC standard was also used for database integration and query process based on B2 GM [79]. BIM and GIS information integration can effectively solve specific practical problems. [PERSON] et al.