# OpenBIM: An Enabling Solution for Information Interoperability
## 3 Overview of OpenBIM
### OpenBIM Software Platforms and Tools
#### 3.2.1 Platforms  
Participants and stakeholders of construction projects can use different BIM software to realize the timely sharing of information [11]. At present, BIM software mainly includes Autodesk, Bentley, and Trimble series. There is a high compatibility between the same company's software, but the interoperability between different companies' software is relatively low, which leads to the difficulty of information sharing between software. Although some of the software has plugin development interface, but still cannot fully meet the construction industry's BIM software requirements about customization and modularization. This section introduces two typical open source software platforms.  
1. BIMserver  
BIMserver is an open and stable software, which can easily build reliable BIM software tools for supporting dynamic collaboration processes of AEC domain users. BIMserver (BIMserver.org) platform enables users to create their own \"BIM operating system\". The core of the software is based on the open IFC standard, so it can handle IFC data well. In BIMserver, the intelligent core interprets IFC data and stores it in the underlying database as an object. The main advantage of this method is that it can query, merge and filter BIM data. In addition to the core database functions of merging, model checking, authorization, authentication, and comparison, there are many other functions that can lower the threshold for developers [12]. BIMserver's common plugins are as follows:  
* IfcOpenShell is an open source software library that helps users and software developers to parse IFC models [13].  
Figure 7: openBIM (building information model) software platforms and tools.  
* bimvie.ws developed an online viewing software tool of BIM built in HTML and Javascript. It is compatible with the BIM Service interface exchange (BIMSie) API interface and works with BIM on the cloud platform. BIMSie is a standard API for BIM Web Services to get BIM in the cloud. Users can use bimvie.ws with any BIMSie-compatible online BIM service [14].
* BIMSurfer is an open source IFC model viewer developed by SceneJS and WebGL to parse BIM data from IFC and gITF formats [15].
* BCFier is an application that can handle BCF files, and it can be integrated directly with BIM software as a plugin. BCFier allows users to create and open BCF files in Autodesk Revit, add multiple views and comments, and easily share them with other team members [16].
2. Extensible Building Information Modeling (xBIM)  
Extensible building information modeling (xBIM) is a free open source software development platform that allows developers to create custom BIM middleware for IFC-based applications [17]. xBIM provides a rich API for IFC data standards. It allows developers to read, write and update IFC files in a few lines of codes.  
xBIM has a complete geometric information engine that converts IFC geometric data objects (such as IfCsweptAreaSolid) into fully functional boundary representation (Brep) geometric models. These models support all Boolean operations, intersection, union, and calculation behaviors such as volume, area, and length. Geometric information engine not only provides optimized 3D triangulation and meshing for visualization, but also provides overall model optimization for repeated recognition and transformation to maps.