Limitless Dynamic Path Generation For Continuous Locomotion in Virtual Reality

Abstract

Walking in a virtual environment is a bounded activity. It is challenging to create and navigate in a large virtual environment given a limited physical space. Various techniques like walking on a treadmill, gesture-based walking and redirected walking address this problem in different ways. These existing solutions have challenges like dependency on additional hardware, inability to adopt different room sizes, compromised rendering quality etc. Such trade-offs make the VR setup immobile and expensive for VR applications which require endless locomotion of the participating subjects. We developed a new redirected walking method to allow the subject to walk continuously within a predefined play area without needing additional hardware support. It is a software-oriented system which dynamically generates an endless path for the participant to walk forward continuously. The system is adaptable to varied play area sizes and is highly mobile because no additional hardware setup is required. Redirected walking consists of methods which actively manipulate the virtual environment to fit it in a smaller physical space. Such techniques allow the user to explore a virtual environment larger than the physical space. Covert redirected walking and overt redirected walking are two sub-classes of the redirected walking techniques. Covert techniques manipulate the environment without being perceivable to the user, and overt redirection techniques do such manipulations while being noticed by the user. Our work is classified as an overt redirected walking technique. The system employs a path generation technique which is inspired by the path generation mechanics of mobile-based endless running games. Generally, the path is composed of successive chunks called “Tiles” in the endless running games. The path initially consists of a fixed number of tiles. When the player begins to move forward, a new tile is added towards the end and a tile is removed from the beginning of the path. This behaviour continues until the user terminates the game. Such an approach creates a perception of an infinitely long path and minimizes memory requirements. We designed an endless path generation system which dynamically generates and updates a path within the bounds of the play area. To evaluate the path generation system, we developed a virtual art gallery. The art gallery is an endless, dynamically generated corridor with paintings/art items hanging on the walls. The path generation system generates and updates the gallery when the user moves forward in the gallery. We conducted three user studies to validate our work and gather feedback to check whether the generated environment induces sickness in the subjects and whether it can adjust to different room sizes without affecting the user’s experience of presence and ease of locomotion. In the last and final user study, we employed a simulator sickness questionnaire (SSQ), a presence questionnaire (PQ) and a custom questionnaire (CQ). No significant differences were found in the scores of all three questionnaires between the two different room sizes. We found an overall low score in the experienced realism sub-scale of the PQ, indicating that the subjects didn’t perceive the generated environment as very real. CQ results suggest that the participants walked normally