A simultaneous walking experience in virtual and real spaces can provide a high sense of presence. However, users may face challenges when walking within a large virtual space while walking in a small and complex real space. Several methods such as Redirected Walking (RDW) and Substitutional Reality (SR) have been proposed as different approaches to this problem. However, the users must “reset” their movement direction at unpredictable moments to avoid collision in a small and complex real space when using subtle RDW that does not maintain the correspondence between virtual and real space. Contrarily, exploration through the SR has a limitation in that the VR scene is restricted to a controlled area. In this paper, we propose Reset at Fixed Positions (RFP), a method that combines RDW with the advantage of the SR and matches walkable real space with walkable virtual space. To utilize RFP, we defined Guaranteed Space Block (GSB), a unit space that constitutes a walkable virtual space. This space is obtained through the point reflection of the GSB utilizing the reset position within the GSB. RFPs can be implemented by two methods: Generating Virtual Space Using RFP (G-RFP) and Implementing Given Virtual Space Using RFP (I-RFP). G-RFP can create an infinitely large virtual space for exploration. On the other hand, I-RFP can conFigure a given virtual environment to make users walk. We observed that G-RFP provides higher presence, immersion and a higher mean distance traveled between resets compared to the existing RDW method in a complex real space through a user study. In addition, exploration through I-RFP provided a higher immersion, a comparable presence, and a similar number of resets.

In multi-user Redirected Walking (RDW), the space subdivision method divides a shared physical space into sub-spaces and allocates a sub-space to each user. While this approach has the advantage of precluding any collisions between users, the conventional space subdivision method suffers from frequent boundary resets due to the reduction of available space per user. To address this challenge, in this study, we propose a space subdivision method called Optimal Space Partitioning (OSP) that dynamically divides the shared physical space in real-time. By exploiting spatial information of the physical and virtual environment, OSP predicts the movement of users and divides the shared physical space into optimal sub-spaces separated with shutters. Our OSP framework is trained using deep reinforcement learning to allocate optimal sub-space to each user and provide optimal steering. Our experiments demonstrate that OSP provides higher sense of immersion to users by minimizing the total number of reset counts, while preserving the advantage of the existing space subdivision strategy: ensuring better safety to users by completely eliminating the possibility of any collisions between users beforehand. Our project is available at https://github.com/AppleParfait/OSP-Archive.