COUP-XR: A Collaborative Cross-Reality System for Urban Planning

This paper presents COUP-XR, a collaborative Extended Reality (XR) system combining Augmented Reality (AR) and Virtual Reality (VR) for participatory urban planning. The system enables stakeholders to visualize and manipulate 3D-printed building models on a physical table (COUP-AR) while simultaneously allowing immersive exploration and modification in VR (COUP-VR). A real-time network setup using Normcore ensures synchronized interaction across devices. Three integrated simulations - pedestrian flow, traffic noise, and wind comfort - support informed decision-making through spatial feedback visualized as heatmaps. A user study with nine participants assessed usability, collaboration efficiency, and XR-based design workflows. Results show high engagement, intuitive handling of the AR interface, and clear potential for enhanced collaboration. Challenges were identified in VR navigation and spatial orientation, indicating a need for improved user support and interface design. COUP-XR demonstrates how XR technologies can bridge physical and digital planning processes, offering a promising direction for future urban design tools that are immersive, collaborative, and data-driven.