Paul Lubos

Bending the Curve: Sensitivity to Bending of Curved Paths and Application in Room-Scale VR

Redirected walking (RDW) promises to allow near-natural walking in an infinitely large virtual environment (VE) by subtle manipulations of the virtual camera. Previous experiments analyzed the human sensitivity to RDW manipulations by focusing on the worst-case scenario, in which users walk perfectly straight ahead in the VE, whereas they are redirected on a circular path in the real world. The results showed that a physical radius of at least 22 meters is required for undetectable RDW. However, users do not always walk exactly straight in a VE. So far, it has not been investigated how much a physical path can be bent in situations in which users walk a virtual curved path instead of a straight one. Such curved walking paths can be often observed, for example, when users walk on virtual trails, through bent corridors, or when circling around obstacles. In such situations the question is not, whether or not the physical path can be bent, but how much the bending of the physical path may vary from the bending of the virtual path. In this article, we analyze this question and present redirection by means of bending gains that describe the discrepancy between the bending of curved paths in the real and virtual environment. Furthermore, we report the psychophysical experiments in which we analyzed the human sensitivity to these gains. The results reveal encouragingly wider detection thresholds than for straightforward walking. Based on our findings, we discuss the potential of curved walking and present a first approach to leverage bent paths in a way that can provide undetectable RDW manipulations even in room-scale VR.

Application of redirected walking in room-scale VR

Redirected walking (RDW) promises to allow near-natural walking in an infinitely large virtual environment (VE) by subtle manipulations of the virtual camera. Previous experiments showed that a physical radius of at least 22 meters is required for undetectable RDW. However, we found that it is possible to decrease this radius and to apply RDW to room-scale VR, i. e., up to approximately 5m × 5m. This is done by using curved paths in the Ve instead of straight paths, and by coupling them together in a way that enables continuous walking. Furthermore, the corresponding paths in the real world are laid out in a way that fits perfectly into room-scale VR. In this research demo, users can experience RDW in a room-scale head-mounted display VR setup and explore a VE of approximately 25m × 25m.

Touching the Cloud: Bimanual annotation of immersive point clouds

In this paper we present “Touching the Cloud”, a bi-manual user interface for the interaction, selection and annotation of immersive point cloud data. With minimal instrumentation, the setup allows a user in an immersive head-mounted display (HMD) environment to naturally interact with point clouds. By tracking the users hands using an OpenNI sensor and displaying them in the virtual environment (VE), the user can touch the virtual 3D point cloud in midair and transform it with pinch gestures inspired by smartphone-based interaction. In addition, by triggering voice- or button-press-activated commands, the user can select, segment and annotate the immersive point cloud, thereby creating hierarchical exploded view models.

Ambiculus: LED-based low-resolution peripheral display extension for immersive head-mounted displays

Peripheral vision in immersive virtual environments is important for application fields that require high spatial awareness and veridical impressions of three-dimensional spaces. Head-mounted displays (HMDs), however, use displays and optical elements in front of a users eyes, which often do not natively support a wide field of view to stimulate the entire human visual field. Such limited visual angles are often identified as causes of reduced navigation performance and sense of presence. In this paper we present an approach to extend the visual field of HMDs towards the periphery by incorporating additional optical LED elements structured in an array, which provide additional low-resolution information in the periphery of a users eyes. We detail our approach, technical realization, and present an experiment, in which we show that such far peripheral stimulation can increase subjective estimates of presence, and has the potential to change user behavior during navigation in a virtual environment.

Control methods in a supernatural flight simulator

This video presents the experimental setup of an immersive flight simulation system, which combines body tracking with a head-mounted display. Users are hanging freely in a climbing harness in order to improve the impression to fly. The base system was created by a group of students during one semester as a bachelor project. A study revealed that a high degree of presence is achievable by the combination of body-posture based control and 3D visualization via a head-mounted display while hanging freely in a climbing gear. Furthermore the results of a study that compares two different steering methods are presented. Both control methods seem to be quite interesting and intuitively controllable but show individual preferences among the participants of the study. In our experiments very frequently strong vaction effects were reported when flying turns to one side. The setup very likely causes simulator sickness, especially if a participant was bad in controlling his flight.

Edutainment & Engagement at Exhibitions: A Case Study of Gamification in the Historic Hammaburg Model.

Gamification in the context of interactive exhibitions has enormous potential to attract visitors and improve their engagement, flow, and learning, in particular when other groups of visitors can share the experience. This paper describes a case study in which we use game-design elements for an interactive and collaborative exploration of a virtual exhibition. Using distinct user interfaces and input devices – a head-mounted display (HMD) and a multi-touch table – two players can explore the virtual 3D Model of the “Hammaburg”, which is a medieval castle of the 9 century and the origin of the German city Hamburg. One player is using a multi-touch table from a bird’s eye perspective, whereas the other player is using an immersive HMD in egocentric perspective, combined with a game controller to navigate through the virtual environment (VE). Both players can interactively explore the shared VE and play a mini game together. The mini game consists of collaborative tasks related to a medieval pottery scene. We performed a user study to evaluate the game concepts and user engagement. The results suggest that communication between the players – both verbal and nonverbal – is a challenging task, and seems especially difficult for the HMD player. Furthermore, this paper proposes an exploration of possibilities and challenges of this setup.

Ring-shaped haptic device with vibrotactile feedback patterns to support natural spatial interaction

Haptic feedback devices can be used to improve usability, performance and cognition in immersive virtual environments (IVEs) and have the potential to significantly improve the users virtual reality (VR) experience during natural interaction. However, there are only few affordable and reliable haptic devices that have a light-weight, unencumbering, simple and versatile form factor which does not prevent natural interaction with other objects or devices at the same time. In this paper we present such a ring-shaped wireless haptic feedback device, and we describe different vibrotactile signal patterns which can be used to provide proximity-based cues during 3D interaction with virtual objects. We present a usability study in which we evaluated the device and feedback patterns.

AnimationVR - Interactive Controller-Based Animating in Virtual Reality

Animating with keyframes gives animators a lot of control but they can be tedious and complicated to work with. Currently, different solutions try to simplify animation creation by recording the natural hand movements of the user. However, most of the solutions are bound to 2D animations [1] or suffer from a low workflow speed [4]. The proposed Unity plugin AnimationVR uses the HTC Vive system to enable the puppeteering animation technique in VR while still allowing for a fast workflow speed by utilizing the 6DOF controllers. During storyboarding or rapid prototyping, the user can immediately see the results of their actions. Also, Animation Vr is written for easy integration in already existing Unity projects. The plug in was evaluated by four animation experts who agreed that Animation Vr accelerates the workflow while decreasing the animation precision. This trade-off makes it useful for storyboarding in professional environments. The experts also noted the ease of use of the puppeteering technique which could enable beginners to create complex animations without any experience with animating.

Safe-&-round: bringing redirected walking to small virtual reality laboratories

Walking is usually considered the most natural form for self-motion in a virtual environment (VE). However, the confined physical workspace of typical virtual reality (VR) labs often prevents natural exploration of larger VEs. Redirected walking has been introduced as a potential solution to this restriction, but corresponding techniques often induce enormous manipulations if the workspace is considerably small and lacks natural experiences therefore. In this poster we propose the Safe-&-Round user interface, which supports natural walking in a potentially infinite virtual scene while confined to a considerably restricted physical workspace. This virtual locomotion technique relies on a safety volume, which is displayed as a semi-transparent half-capsule, inside which the user can walk without manipulations caused by redirected walking.

The significance of stereopsis and motion parallax in mobile head tracking environments

Despite 3D TVs and applications gaining popularity in recent years, 3D displays on mobile devices are rare. With low-cost head tracking solutions and first user interfaces available on smartphones, the question arises how effective the 3D impression through motion-parallax is and whether it is possible to achieve viable depth perception without binocular stereo cues. As motion parallax and stereopsis may be considered the most important depth cues, we developed an experiment comparing the users depth perception utilizing head tracking with and without stereopsis.