FROM BIM TO INTERACTIVE DIGITAL TWIN: A WORKFLOW FOR INTEGRATING VIRTUAL AND PHYSICAL ENVIRONMENTS

The fragmentation among Building Information Models (BIM), IoT sensor networks, and facility management interfaces severely limits the operational value of digital construction investments. The architecture, engineering, and construction (AEC) sector requires practical workflows that extend the use of BIM beyond design and construction into facility operations. This paper presents a validated open-source methodology for transforming static IFC models into interactive augmented virtual reality (VR) digital twins using Unreal Engine 5.5. The approach has been implemented through a 4-level university building case study. The proposed system combines IFC building geometry with real-time HOBO sensor data (temperature, humidity, and CO2) using a three-tier navigation architecture that bridges 2D floor plans and 3D spatial exploration. Using Datasmith for model processing and Blueprint visual scripting for interaction logic, the workflow supports both desktop and VR deployment modes without requiring programming expertise. Performance validation demonstrates sub-100 ms response times for all interactions, teleportation for predefined spaces, and consistent 120 FPS desktop/90-120 FPS VR operation while processing live sensor streams. The multi-modal interface design enables progressive complexity adoption, allowing facility managers to transition from familiar 2D interfaces to immersive 3D environments at their own pace. This democratized approach uses freely available tools to make digital twin technology accessible to educational institutions and small-to-medium enterprises previously excluded by proprietary platform costs. The validated workflow directly provides practical implementation patterns for BIM-to-digital-twin transformation. This solution serves AEC researchers and academic institutions seeking an open, extensible framework for experimental digital twin development, immersive visualization research, and real-time BIM–IoT integration studies without reliance on proprietary platforms.