## 2 Methodology  
The business problem encountered by AEC and CAFM professionals has been discussed in the preceding section. Specifically, spatially referenced building data, which are crucial for CAFM and reside within BIMs, are frequently inaccessible or overly complex for effective utilisation by facility managers. Through literature analysis and the author's empirical insights as research-driven facility managers and integrators of innovation into a research facility [64], this research determines that VT can offer a solution to the business problem. In this sense, and as illustrated in Figure 2, VT is regarded as an operational point of entry for CAFM users to access IoT and BIM data. Consequently, a VT has been developed based on the methodology outlined below. This VT enables navigation through the interiors and exteriors of various assets, as well as consultation of monitoring (IoT) and BIM data. The VT is composed of georeferenced photographs captured periodically on a lapse of one year using 360\({}^{\circ}\) cameras and drones [65; 66]. The tour also features an accreditation module providing access to building data according to user category, ranging from public to specialised scientists. To evaluate the IoT-VT-BIMs connectivity (see Figure 2), the Controlled Environments for Living Lab Studies (CELLS) [67] has been used. CELLS is a twin-room HVAC autonomous pavilion that allows the control and monitoring of indoor comfort conditions  
Figure 1: Added value of BIMs and VTs, in relation to the building life-cycle phase. Figure 2: AEC and CAFM entry points to the Information-control loop between the build object, BIMs, and VT.  
and building management systems, including automation of certain functionalities. CELLS operates as an \"incubator\" to benchmark and validate systems that will be functional on real buildings, including the current [68] and future offices of the Smart Living Lab [69]. This future application is relevant to this research, as it involves CAFM at a high level of complexity, including flexible monitoring and remote-control processes. The future office building features dismantlable facade modules for testing and monitoring new envelope materials, as well as flexible partitions accommodating a range of spatial layouts and various office sizes. This future system is based on a 3 by 3 m module, where each module can be individually controlled thanks to a specialised HVAC system [64]. The case study of CELLS provides a unique perspective on this integration, offering a practical example of how these technologies can be implemented in real-world settings. The constructive characteristics of this pavilion, including its building envelope, the double-glazed windows, and the HVAC and electric systems, provide optimal and reliable conditions for the operations and measurements involved in the experiment. To create the VT and establish its connection to IoT and BIM data, the following steps have been taken:  
1. System data setting * IoT: CELLS is equipped with a number of IoT elements, including sensors (temperature (interior and exterior), wind speed, rain, inlet power consumption, lighting fixtures, active power, lighting intensity, etc. ), as well as controllers (blinds (up/down), lighting switches (on/off), among others). For the demonstrative purposes of this research, two specific system elements have been fully integrated into the IoT-VT-BIMs (see Figure 2) connection: light control (on/off) and historical temperature inquiry (interior and exterior). Remote control and inquiring of these elements using HTTP protocols and interface are set. * BIMs: a digital replica of the pavilion was modelled using the BIM software Autodesk Revit v.2023 [70], and according to an LOI 400 standard [14]. In previous research, this model was successfully integrated into a VR environment and linked to the related IoT data [22].