# Thermal Performance Visualization Using Object-Oriented Physical and Building Information Modeling
## 3 Objective and Approach  
The objective of this study was to facilitate sustainable design through information visualization of OOPM\(-\)BEPS results in the early design stage. To achieve this goal, we developed a platform by integrating BIM and the results from OOPM\(-\)BEPS tools (i.e., we integrated the capability of OOPM\(-\)BEPS visualization in BIM).  
For this integration, our research method is based on the BIM technologies including the API of the BIM tools and OOPM\(-\)BEPS using the OOPM method. Even BIM facilitates access to comprehensive building information that accumulate throughout the building's lifecycle [20] and allows parametric modeling in the design stage, OOPM supports object-oriented building performance simulation results [21]. Our research utilizes the advantages of BIM and OOPM\(-\)BEPS for visualization--an object-based modeling approach for building and energy modeling and an object-oriented programming method. The object-based modeling approach enables direct access to BIM and simulation results, and the object-oriented computer programming method facilitates a system interface for visualization between BIM and OOPM\(-\)BEPS. Figure 1 shows the overall process of this research, including all steps and activities (A1, A2, A3, and A4).  
The green component (A1) in Figure 1 represents the process of creating a BIM model, including the information required to create an OOPM\(-\)BEPS. The A1 activity consists of the following three major control components: (1) visibility setting and TEPI parameter, (2) physical properties, and (3) design intent and specifications. The stakeholders and specific tool, represented as architects/engineers and BIM authoring tools in the A1 activity, enable a BIM model to be created with particular values for the controls. The output from the A1 activity is a BIM model consisting of geometry and no geometry information.  
The blue component in Figure 1 is the OOPM\(-\)BEPS process adopted from [12; 14; 15; 23; 24]. Previous work integrating BIM and OOPM-based building energy model (BEM) evaluated the use of object-oriented BIM and BEM, enabling more reliable and efficient model translation and guaranteeing efficient maintainability [12; 14; 15; 23; 24]. The A2 activity represents the object-based BEPS method adopted for thermal energy performance simulations, based on the BIM model. The control components of the A2 activity include the physical BIM library developed from [14] and object-oriented physical library developed from [25]. The control components facilitate model translation and BIM-based OOPM\(-\)BEM [12; 14; 23]. The three main control components (i.e., OOPM using Modelica, API, and Mechanism) of the A1 activity enable model translation between BIM and OOPM\(-\)based BEM under two control components. Thus, three OOPM\(-\)BEM model translated from the BIM model can be used to conduct building energy performance simulations and provide object-oriented thermal simulation results.  
The simulation results from the A2 activity are converted as input data for the A3 activity. The main function of A3 is to create an external database to accumulate the object-based thermal simulation results from the A2 activity. Even simulation results consisting of object-based results mapped with specific building components including walls and floors are still composed of a large quantity of numerical simulation results. In order to access specific information among the results, each value needs to be stored in individual containers such as cells in the external database applications (Excel or Access).  
The A4 activity represents the TEPV workflow. The activity has geometric information from the A1 activity as the input and database information from the A3 activity as the control component. Based on the input and control component, the specific value is represented as a color-coded building component under the API mechanism and BIM authoring tool.  
Figure 1: Overall process diagram using Integration Definition of Function Modeling(IDEF)0 [22].