# BIM-Based Management System for Off-Site Construction Projects
## 4 System Implementation
### Development Environment  
Table 1 summarizes the system implementation environment, which consists of the fundamental and functional parts for BIM-based project management. The proposed system has the following essential environmental elements. Considering the usability, Microsoft Windows, a popular OS, is used, and Microsoft.NET is applied to ensure smooth program development and execution. Moreover, the system involves a program based on Microsoft Visual Studio, an IDE that can develop all desktop and web applications to be run on Windows. The program is implemented in Microsoft C#, a language that works reliably and efficiently in this environment. The MariaDB is used to manage the massive data created, changed, and stored in the system. The MariaDB is an open DBMS with high compatibility and openness with other programs and is widely used for development owing to its stable performance. Each server is established based on CentOS Linux for web access authentication and content management, application execution and DB access, and the management of the DB and file data. Furthermore, the system has a 3D model view-based interface and API environment to implement BIM technology-based functions to facilitate OSC project execution. The 3D view interface environment is established using DevDept's Eyeshot, and DevExpress's UI is used for program input/output and operation control. The system also includes an API for xbim toolkit, openBIM, to ensure that the IFC format, which is a platform-neutral, open data scheme of BIM, can be recognized and edited in this program. In addition to the BIM models and drawings, this system includes APIs for Microsoft Excel to input or output various text and numerical data generated during OSC projects. ### Development Environment  
The system implementation is illustrated in Figure 1: the basic requirements of the system are designed and incorporated considering the OSC project management requirements presented in Section 3. After implementing the detailed functions, the development is performed through repeated testing and improvement processes. The system designs and implements the relational DB and UI to effectively manage the various kinds of information in the OSC project. The data loaded into the DB are divided into information already generated in the design phase and information to be additionally generated in the construction phase (Figure 2). \begin{table}
\begin{tabular}{l l} \hline \hline
**Name** & **Role** \\ \hline Microsoft Windows 8/8.1/10 & Operation system \\ Microsoft.NET 4x & Framework \\ Microsoft Visual Studio 201x & Integrated development environment (IDE) \\ MariaDB 10.x & Database management system (DBMS) \\ Microsoft C# 7.x & Programming language \\  & Server for web access authentication and content \\ CentOS 8.x & management, application execution environment and \\  & database (DB) connection, DB, and file data management \\ DevDept Eyeshot 12 & Three-dimensional view interface \\ DevExpress 18.x & Windows user interface (UI) control library \\ xbim toolkit 5.1.x & Application programming interface (API) for.ifc controls \\ Microsoft Excel 14.x & Data input/output format API \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Development environment and components. Figure 1: System development process. Tekla Structures, a widely used component design program for OSC projects, can export the model in an IFC format readable by the system. The core information in the IFC file imported into this system is stored in related objects (i.e., project and elements/drawing management) in the DB. According to the defined relationship in this system, the production, logistics, and installation steps are performed, and the information generated during the steps is managed. In addition to the model data, the information that needs to be pre-constructed is imported into the system and used for digital-based OSC project execution using BIM.