## 5 Interactive Function Development and Plug-In Application Interface Design
### Platform Usage Evaluation
#### 5.3.2 Questionnaire Statistical Results  
This section is explained based on the above expert interview results. First, the questionnaire results are divided into six grades according to the SUS calculation method [26], which presents the calculation and evaluation results of the usability of the system built in this study. According to the statistical results of the questionnaire (Figure 9), the Unity integration platform helps to expand the application of the BIM models of historic information, which uses game technology to visualize information and develop interactive functions, strengthens the interaction between the user and information, includes restoration information for added value, and effectively reduces the difficulty of traditional BIM operation. The dynamic and static perspective switch provided by the platform improved the interactive experience between the user and the model, and information can be accurately transmitted between Revit and the Unity integration platform through the iData+ application interface. The automatic bi-directional information transmission function makes the integration process more logical and easier to operate. The interface application design is relatively user-friendly and achieves the design purpose of providing the user with information interaction. Intensifying the application of value-added information brings more possibilities for the restoration and conservation of historic buildings in the future.  
Regarding the platform management end, the workflow of importing the models and information into the integration platform may be simplified through the iData+ application interface, which also reduces the development complexity of application functions and programs. More auxiliary functions can be developed in the future, including classifying the restoration information and building the automatic information classification function according to the restoration craftsmen or the different periods of restoration. At present, users are required to complete input fields; however, if the workflow can be automated,  
Figure 9: Statistical results of the questionnaire.  
the application to historic buildings will be more diversified, and the feasibility of big data application will be improved.  
In addition, regarding the option of the \"visual information list\", as provided by the Unity integration platform (Figure 7), the relationship between the physical model component and corresponding component name button is not intuitive enough; thus, users cannot directly click on the physical model, but must find the corresponding component name button in the information list before pressing the button, which is not convenient or intuitive for the user. In addition, as the interface switch between Unity and Revit platforms requires supplementary instructions, this system is not easy enough for beginners, but usage may be improved as the user becomes familiar with the operation process.  
This research focuses on the combination of the Revit plug-in interface application and the Unity platform. It is an experimental interactive interface development. The current preliminary results are evaluated by expert questionnaires. In this questionnaire, architects with experience in restoration of historical sites and experts with experience in system development are selected as the subjects of the questionnaire. The limited number of architects with experience in restoration of historical sites does limit the number of questionnaires and also affects the validity. However, the evaluation recommendations obtained from the results of the current research phase can still be expected as a reference for future research and subsequent system improvements (see Section 6.2 for the reference).