@article{doi:10.1177/0018720819853682,
author = {Abdulaziz Alshaer and David O’Hare and Philippe Archambault and Mark Shirley and Holger Regenbrecht},
title ={How to Observe Users’ Movements in Virtual Environments: Viewpoint Control in a Power Wheelchair Simulator},
journal = {Human Factors},
volume = {0},
number = {0},
pages = {0018720819853682},
year = {0},
doi = {10.1177/0018720819853682},
    note ={PMID: 31306040},

URL = { 
        https://doi.org/10.1177/0018720819853682
    
},
eprint = { 
        https://doi.org/10.1177/0018720819853682
    
}
,
    abstract = { Objective:We describe a networked, two-user virtual reality (VR) power wheelchair (PWC) simulator system in which an actor (client) and an observer (clinician) meet. We then present a study with 15 observers (expert clinicians) evaluating the effect of three principal forms of viewpoint control (egocentric-egomotion, egocentric-tethered, and client-centric) on the observer’s assessment of driving tasks in a virtual environment (VE).Background:VR allows for the simulation and assessment of real-world tasks in a controlled, safe, and repeatable environment. Observing users’ movement behavior in such a VE requires appropriate viewpoint control for the observer. The VR viewpoint user interface should allow an observer to make judgments equivalent or even superior to real-world situations.Method:A purpose-built VR PWC simulator was developed. In a series of PWC driving tasks, we measured the perceived ease of use and sense of presence of the observers and compared the virtual assessment with real-world “gold standard” scores, including confidence levels in judgments.Results:Findings suggest that with more immersive techniques, such as egomotion and tethered egocentric viewpoints, judgments are both more accurate and more confident. The ability to walk and/or orbit around the view significantly affected the observers’ sense of presence.Conclusion:Incorporating the observer into the VE, through egomotion, is an effective method for assessing users’ behavior in VR with implications for the transferability of virtual experiences to the real world.Application:Our application domain serves as a representative example for tasks where the movement of users through a VE needs to be evaluated. }
}