Infinite Spaces Using Recursive Portals

One of the strongest aspects of virtual reality (VR) hardware and applications is the immersion it provides to the user. While combination of techniques such as real-walking for locomotion, head movement for gaze direction and hand detection for controls are great for immersive experience; when the real space and the virtual environment does not match, developers must resort to alternative locomotion techniques such as teleportation, controller-assisted movement or in-place walking via external devices. Despite lifting the restrictions on physical spaces, these techniques may need expensive or cumbersome hardware, cause nausea and dizziness on the user or simply diminish the immersion. We propose a portal based environment design method and a modern rendering engine to visualize the created scenes. Our method uses the same physical space by overlapping multiple regions of the virtual environment on top of each other while keeping the affine properties of the scene. The user can walk between different virtual rooms while staying in a limited physical space. We also conduct a user study to compare user experience to state-of-the-art physical-virtual environment mapping method; in which, the users strongly favored our method.