Safe-&-Round: Bringing Redirected Walking to SmallVirtual Reality Laboratories

Paul LubosDepartment of Informatics

University of Hamburgpaul.lubos@uni-hamburg.de

Gerd BruderDepartment of Informatics

University of Hamburggerd.bruder@uni-hamburg.de

Frank SteinickeDepartment of Informatics

University of Hamburgfrank.steinicke@uni-

hamburg.de

ABSTRACTWalking is usually considered the most natural form for self-motion in a virtual environment (VE). However, the confinedphysical workspace of typical virtual reality (VR) labs of-ten prevents natural exploration of larger VEs. Redirectedwalking has been introduced as a potential solution to thisrestriction, but corresponding techniques often induce enor-mous manipulations if the workspace is considerably smalland lacks natural experiences therefore.

In this poster we propose the Safe-&-Round user interface,which supports natural walking in a potentially infinite vir-tual scene while confined to a considerably restricted physi-cal workspace. This virtual locomotion technique relies on asafety volume, which is displayed as a semi-transparent half-capsule, inside which the user can walk without manipula-tions caused by redirected walking.

Author KeywordsSpatial user interfaces; locomotion; virtual environments

ACM Classification KeywordsH.5.m. Information Interfaces and Presentation (e. g. HCI):Miscellaneous

SAFE-&-ROUND USER INTERFACEWhen walking through a VE we distinguish between threestages in the Safe-&-Round user interface (see Figure 1):(i) walking in the safe inner region, (ii) redirected walkingaround the outer path, and (iii) a transition between these twostages.

A user can freely walk within the safe inner region wheremovements match between the real and virtual space. Theboundaries of the workspace are represented by a semi-transparent half-capsule. When approaching the boundariesof the safe inner region, the opacity of the barrier increases toinform users that they are about to enter the redirected walk-ing path. Once the user walks through the semi-transparentbarrier, we compute the minimum angle necessary to reorient

inner radius

path widthsafety area

outer radius

redirected walking path

center

HMD

Figure 1. User exploring a VE using the Safe-&-Round interface. Illus-trations show the safety area and the redirected walking path. The insetshows the user’s view with a visual barrier to his right side preventinghim from physical collisions.them and start to apply camera rotations to guide them on thepath that leads around the inner safety area (see Figure 1).

After users transitioned onto the redirected walking path, vi-sual cues in the form of a virtual barrier [1] are used to in-form users that this path is located close to the boundaries ofthe workspace, which prevents collisions with physical ob-stacles in the real world. The redirected walking path leadsaround the circular safety area, creating a circular path withthe maximum possible radius in the physical workspace [2],thus providing a near-constant and predictable magnitude ofmanipulations.

Once users come close to an object of interest in the VE, wedetermine the remaining visual distance during walking andslowly start reorienting the user such that the region of inter-est falls into the safety region once the user reaches the target.The user then can perform tasks within the virtual workspaceat the new location.REFERENCES1. Cirio, G., Marchal, M., Regia-Corte, T., and Lecuyer, A.

The magic barrier tape: A novel metaphor for infinitenavigation in virtual worlds with a restricted walkingworkspace. In Proc. of ACM VRST, ACM Press (2009),155–162.

2. Steinicke, F., Bruder, G., Jerald, J., Fenz, H., and Lappe,M. Estimation of Detection Thresholds for RedirectedWalking Techniques. IEEE Transactions on Visualizationand Computer Graphics (TVCG) 16, 1 (2010), 17–27.

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