Object Manipulation in Virtual Reality Under Increasing Levels of Translational Gain

Room-scale Virtual Reality (VR) has become an affordable consumer reality, with applications ranging from entertainment to productivity. However, the limited physical space available for room-scale VR in the typical home or office environment poses a significant problem. To solve this, physical spaces can be extended by amplifying the mapping of physical to virtual movement (translational gain). Although amplified movement has been used since the earliest days of VR, little is known about how it influences reach-based interactions with virtual objects, now a standard feature of consumer VR. Consequently, this paper explores the picking and placing of virtual objects in VR for the first time, with translational gains of between 1x (a one-to-one mapping of a 3.5m*3.5m virtual space to the same sized physical space) and 3x (10.5m*10.5m virtual mapped to 3.5m*3.5m physical). Results show that reaching accuracy is maintained for up to 2x gain, however going beyond this diminishes accuracy and increases simulator sickness and perceived workload. We suggest gain levels of 1.5x to 1.75x can be utilized without compromising the usability of a VR task, significantly expanding the bounds of interactive room-scale VR

ARC: Alignment-based Redirection Controller for Redirected Walking in Complex Environments

We present a novel redirected walking controller based on alignment that allows the user to explore large and complex virtual environments, while minimizing the number of collisions with obstacles in the physical environment. Our alignment-based redirection controller, ARC, steers the user such that their proximity to obstacles in the physical environment matches the proximity to obstacles in the virtual environment as closely as possible. To quantify a controller's performance in complex environments, we introduce a new metric, Complexity Ratio (CR), to measure the relative environment complexity and characterize the difference in navigational complexity between the physical and virtual environments. Through extensive simulation-based experiments, we show that ARC significantly outperforms current state-of-the-art controllers in its ability to steer the user on a collision-free path. We also show through quantitative and qualitative measures of performance that our controller is robust in complex environments with many obstacles. Our method is applicable to arbitrary environments and operates without any user input or parameter tweaking, aside from the layout of the environments. We have implemented our algorithm on the Oculus Quest head-mounted display and evaluated its performance in environments with varying complexity. Our project website is available at https://gamma.umd.edu/arc/

LoCoMoTe – a framework for classification of natural locomotion in VR by task, technique and modality

Virtual reality (VR) research has provided overviews of locomotion techniques, how they work, their strengths and overall user experience. Considerable research has investigated new methodologies, particularly machine learning to develop redirection algorithms. To best support the development of redirection algorithms through machine learning, we must understand how best to replicate human navigation and behaviour in VR, which can be supported by the accumulation of results produced through live-user experiments. However, it can be difficult to identify, select and compare relevant research without a pre-existing framework in an ever-growing research field. Therefore, this work aimed to facilitate the ongoing structuring and comparison of the VR-based natural walking literature by providing a standardised framework for researchers to utilise. We applied thematic analysis to study methodology descriptions from 140 VR-based papers that contained live-user experiments. From this analysis, we developed the LoCoMoTe framework with three themes: navigational decisions, technique implementation, and modalities. The LoCoMoTe framework provides a standardised approach to structuring and comparing experimental conditions. The framework should be continually updated to categorise and systematise knowledge and aid in identifying research gaps and discussions

Real walking in virtual environments for factory planning and evaluation

Nowadays, buildings or production facilities are designed using specialized design software and building information modeling tools help to evaluate the resulting virtual mock-up. However, with current, primarily desktop based tools it is hard to evaluate human factors of such a design, for instance spatial constraints for workforces. This paper presents a new tool for factory planning and evaluation based on virtual reality that allows designers, planning experts, and workforces to walk naturally and freely within a virtual factory. Therefore, designs can be checked as if they were real before anything is built.ISSN:2212-827

Redirected Walking in Infinite Virtual Indoor Environment Using Change-blindness

We present a change-blindness based redirected walking algorithm that allows a user to explore on foot a virtual indoor environment consisting of an infinite number of rooms while at the same time ensuring collision-free walking for the user in real space. This method uses change blindness to scale and translate the room without the user's awareness by moving the wall while the user is not looking. Consequently, the virtual room containing the current user always exists in the valid real space. We measured the detection threshold for whether the user recognizes the movement of the wall outside the field of view. Then, we used the measured detection threshold to determine the amount of changing the dimension of the room by moving that wall. We conducted a live-user experiment to navigate the same virtual environment using the proposed method and other existing methods. As a result, users reported higher usability, presence, and immersion when using the proposed method while showing reduced motion sickness compared to other methods. Hence, our approach can be used to implement applications to allow users to explore an infinitely large virtual indoor environment such as virtual museum and virtual model house while simultaneously walking in a small real space, giving users a more realistic experience.Comment: https://www.youtube.com/watch?v=s-ZKavhXxd

Sensitivity to Rate of Change in Gains Applied by Redirected Walking

Redirected walking allows for natural locomotion in virtual environments that are larger than a user’s physical environment. The mapping between real and virtual motion is modified by scaling some aspect of motion. As a user traverses the virtual environment these modifications (or gains) must be dynamically adjusted to prevent collision with physical obstacles. A significant body of work has established perceptual thresholds on rates of absolute gain, but the effect of changing gain is little understood. We present the results of a user study on the effects of rate of gain change. A psychophysical experiment was conducted with 21 participants. Each participant completed a series of two-alternative forced choice tasks in which they determined whether their virtual motion differed from their physical motion while experiencing one of three different methods of gain change: sudden gain change, slow gain change and constant gain. Gain thresholds were determined by 3 interleaved 2-up 1-down staircases, one per condition. Our results indicate that slow gain change is significantly harder to detect than sudden gain change

Altering User Movement Behaviour in Virtual Environments.

In immersive Virtual Reality systems, users tend to move in a Virtual Environment as they would in an analogous physical environment. In this work, we investigated how user behaviour is affected when the Virtual Environment differs from the physical space. We created two sets of four environments each, plus a virtual replica of the physical environment as a baseline. The first focused on aesthetic discrepancies, such as a water surface in place of solid ground. The second focused on mixing immaterial objects together with those paired to tangible objects. For example, barring an area with walls or obstacles. We designed a study where participants had to reach three waypoints laid out in such a way to prompt a decision on which path to follow based on the conflict between the mismatching visual stimuli and their awareness of the real layout of the room. We analysed their performances to determine whether their trajectories were altered significantly from the shortest route. Our results indicate that participants altered their trajectories in presence of surfaces representing higher walking difficulty (for example, water instead of grass). However, when the graphical appearance was found to be ambiguous, there was no significant trajectory alteration. The environments mixing immaterial with physical objects had the most impact on trajectories with a mean deviation from the shortest route of 60 cm against the 37 cm of environments with aesthetic alterations. The co-existance of paired and unpaired virtual objects was reported to support the idea that all objects participants saw were backed by physical props. From these results and our observations, we derive guidelines on how to alter user movement behaviour in Virtual Environments