# Developing a BIM-Based MUVR Treadmill System for Architectural Design Review and Collaboration
## 6 Discussion  
This study developed a system that integrates MUVR applications into omnidirectional treadmills. A prototype was set up and tested by the participants to validate the system in user interaction, user locomotion, and system synchronization. This section discusses the results of applying the system in architectural design review and collaboration. Firstly, collaborative VR allows multiple users to attend design review sessions in the shared virtual environment. According to the results, the system can enhance interaction experiences facilitated by the interactive functions of the VR platform. Based on the means of the user interaction measures, they were rated well by the participants, especially the interactive experience during the design overview. In this case, the participants used most interaction tools (i.e., scale-model mode, measurement tool, and primitive creation tool) to review design options of the building model with their partners. With the VR treadmills, the participants could walk around the same way that they would in reality, achieving more realistic interactions and collaboration in the immersive virtual environment. Moreover, VR is not just a valuable means of design visualizations or model walkthroughs; it can also be used as an effective design tool. According to the results, designing in the virtual environment is possible. The interactive functions of the system allow the innovative design to be created in the shared virtual environment. For the conflict resolutions and design detailing, the participants were satisfied with the system. During the testing, the participants were involved in the tasks about clarifications of the headroom clearance of lift door openings and verifications of the assembly details of glass ballustrades. Using MUVR for architectural design review allows architects and their team members to step into the building model for interactions. They can assess any virtual spaces inside the building to better understand spatial requirements and stimulated final products. This type of collaborative immersion enhances strong team communication and enables true collaborative design, ultimately speeding up the whole design process. These findings are in line with those of previous studies on the effects of VR on the design review process, particularly the enhanced interactions arising from MUVR applications. Secondly, human locomotion is a VR technology that enables the movement from one place to another in the virtual environment. In this study, human locomotion was enabled by the omnidirectional treadmills that offer users high-level simulations of the natural movement and alleviate their VR sickness. The participants highly appreciated the system's safety, as the harness protection locks the user securely on the treadmills. Generally, VR applications can be set up in any space. For that reason, the larger the room space, the farther the users can walk within the perceived environment. However, for a room-scale VR setup, the users might come to the physical limits of the room and choose to teleport themselves to a different virtual location. In this study, the participants walked around the building models to review architectural design without limitations. However, the participants showed concerns about the agility and preciseness of using the system. The omnidirectional treadmills provide platforms that enhance the illusion of unconstrained movement. With the harness protections, the participants can move naturally in a linear direction on every building floor. Nevertheless, running motions inside the building model were not recommended, due to the slipperiness of the overshoes worn by the users. Most of the participants also felt difficulty stopping precisely, due to the reduced foot friction on the treadmills. This deficiency disturbed the participants, because they needed to move back and forth until reaching a particular location to discuss the design matter with their partners.