Immersive Virtual Environments (IVEs) incorporating tangible graspable objects are becoming more accessible for training and other applications. Visual and proprioceptive information has been shown to be important for accurate distance and size perception. However, previous research has shown that users overestimate the size of tangible objects in IVEs. To address this issue, researchers have demonstrated the use of calibration to alter users' perceptions. In this study, we examined the carryover effects of calibration on the perceived size of graspable dials in IVEs. Participants wore head-mounted displays and experienced two calibration perturbations: Divergent Plus (physical dials 10% larger than virtual) and Divergent Minus (physical dials smaller than virtual). These were compared to the baseline Convergent condition (equal diameters). The results showed significant effects of the calibration on the accuracy of diameter estimates. Overall, a higher overestimation of dial sizes for the haptics-only condition was observed as compared to the vision-only condition. Additionally, participants' estimations worsened when haptic information was added to the vision during calibration but improved when vision information was added to the haptics-only condition during calibration. These findings highlight the importance of calibration in improving the accuracy of size perception in IVEs and contribute to our understanding of how tangible graspable objects are perceived in immersive virtual environments.

AR/VR devices have started to adopt hand tracking, in lieu of controllers, to support user interaction. However, today’s hand input rely primarily on one gesture: pinch. Moreover, current mappings of hand motion to use cases like VR locomotion and content scrolling involve more complex and larger arm motions than joystick or trackpad usage. STMG increases the gesture space by recognizing additional small thumb-based microgestures from skeletal tracking running on a headset. We take a machine learning approach and achieve a 95.1% recognition accuracy across seven thumb gestures performed on the index finger surface: four directional thumb swipes (left, right, forward, backward), thumb tap, and fingertip pinch start and pinch end. We detail the components to our machine learning pipeline and highlight our design decisions and lessons learned in producing a well generalized model. We then demonstrate how these microgestures simplify and reduce arm motions for hand-based locomotion and scrolling interactions.

Over the past two decades self-avatars have been shown to affect the perception of both oneself and of environmental properties including the sizes and distances of elements in immersive virtual environments. However, virtual avatars that accurately match the body proportions of their users remain inaccessible to the general public. As such, most virtual experiences that represent the user have a generic avatar that does not fit the proportions of the users' body. This can negatively affect judgments involving affordances, such as passability and maneuverability, which pertain to the relationship between the properties of environmental elements relative to the properties of the user providing information about actions that can be enacted. This is especially true when the task requires the user to maneuver around moving objects like in games. Therefore, it is necessary to understand how different sized self-avatars affect the perception of affordances in dynamic virtual environments. To better understand this, we conducted an experiment investigating how a self-avatar that is either the same size, 20% shorter, or 20% taller, than the user's own body affects passability judgments in a dynamic virtual environment. Our results suggest that the presence of self-avatars results in better regulatory and safer road crossing behavior, and helps participants synchronize self-motion to external stimuli quicker than in the absence of self-avatars.

With the popularity of Virtual Reality (VR) on the rise, creators from a variety of fields are building increasingly complex experiences that allow users to express themselves more naturally. Self-avatars and object interaction in virtual worlds are at the heart of these experiences. However, these give rise to several perception based challenges that have been the focus of research in recent years. One area that garners most interest is understanding the effects of self-avatars and object interaction on action capabilities or affordances in VR. Affordances have been shown to be influenced by the anthropometric and anthropomorphic properties of the self-avatar embodied. However, self-avatars cannot fully represent real world interaction and fail to provide information about the dynamic properties of surfaces in the environment. For example, pressing against a board to feel its rigidity. This lack of accurate dynamic information can be further amplified when interacting with virtual handheld objects as the weight and inertial feedback associated with them is often mismatched. To investigate this phenomenon, we looked at how the absence of dynamic surface properties affect lateral passability judgments when carrying virtual handheld objects in the presence or absence of gender matched body-scaled self-avatars. Results suggest that participants can calibrate to the missing dynamic information in the presence of self-avatars to make lateral passability judgments, but rely on their internal body schema of a compressed physical body depth in the absence of self-avatars.

The availability of new and improved display, tracking and input devices for Virtual Reality experiences has facilitated the use of partial and full body self-avatars in interaction with virtual objects in the environment. However, scaling the avatar to match the user's body dimensions remains to be a cumbersome process. Moreover, the effect of body-scaled self-avatars on size perception of virtual handheld objects and related action capabilities has been relatively unexplored. To this end, we present an empirical evaluation investigating the effect of the presence or absence of body-scaled self-avatars and visuo-motor calibration on frontal passability affordance judgments when interacting with virtual handheld objects. The self-avatar's dimensions were scaled to match the participant's eyeheight, arms length, shoulder width and body depth along the mid section. The results indicate that the presence of body-scaled self-avatars produce more realistic judgments of passability and aid the calibration process when interacting with virtual objects. Also, participants rely on the visual size of virtual objects to make judgments even though the kinesthetic and proprioceptive feedback of the object is missing or mismatched.

Prototyping electronic circuits is often facilitated by web-based tutorials and breadboards. Several virtual and hybrid platforms do exist, each carrying their own limitations. Some of these platforms fall prey to split-attention effects, wherein users are required to split their attention to integrate multiple sources of spatially separated information. This hinders the learning and prototyping processes. Other platforms provide a single source of information, but lack tangible interaction with electronic components or suffer from the absence of active feedback which can also hinder these processes. There is hence a need for prototyping platforms that mitigate split attention effects, while continuing to provide other desirable aspects such as tangible interaction. To address this, we present three editions of PPCards, a card-based platform for prototyping electronic circuits, towards overcoming limitations of existing paradigms. Through a comparative study, it was determined that the first edition of PPCards outdid the conventional breadboard web-based tutorial paradigm in aspects of split attention, usability, and user experience. The second and third editions build upon successful characteristics of the first, additionally provisioning support for multimedia content and real-time feedback during the prototyping process. Based on quantitative data and qualitative feedback, we go on to discuss design considerations for future tangible card-based tools.

Immersive Virtual Environments (IVEs) incorporating tangibles are becoming more accessible. The success of applications combining 3D printed tangibles and VR often depends on how accurately size is perceived. Research has shown that visuo-haptic perceptual information is important in the perception of size. However, it is unclear how these sensory-perceptual channels are affected by immersive virtual environments that incorporate tangible objects. Towards understanding the effects of different sensory information channels in the near field size perception of tangibles of graspable sizes in IVEs, we conducted a between-subjects study evaluating the accuracy of size perception across three experimental conditions (Vision-only, Haptics-only, Vision and Haptics). We found that overall, participants consistently over-estimated the size of the dials regardless of the type of perceptual information that was presented. Participants in the haptics only condition overestimated diameters to a larger degree as compared to other conditions. Participants were most accurate in the vision only condition and least accurate in the haptics only condition. Our results also revealed that increased efficiency in reporting size over time was most pronounced in the visuo- haptic condition.

As Virtual Reality (VR) devices become more accessible, a multitude of VR applications engage users in highly immersive virtual environments that feature realistic graphics, real-life scenarios, and self-avatars. Many of these simulations require users to make spontaneous affordance judgments such as stepping over obstacles, passing through gaps, etc. which are shown to be affected by the nature of our self-representation in the virtual world. As the technology for creating self-avatars becomes more widely available, it is important to explore how various affordance judgments are affected by the presence of self-avatars. In this work, we investigate the effects of body-scaled self-avatars on the affordance of passability in a natural setting. We implemented a gender-matched body-scaled self-avatar using HTC Vive trackers and evaluated how passability judgments for a sliding doorway in VR, with and without an avatar, compared to the real world judgments. The results suggest that passability judgments are more conservative in VR as compared to the real world. However, the presence of a self-avatar does not significantly affect passability judgments made in VR. This does not align with previous findings which show that having a self-avatar improves judgments and estimates.

The commercialization and lowering costs of consumer grade Virtual Reality (VR) devices has made the technology increasingly accessible to users around the world. The usage of VR technology is often accompanied by an undesirable side effect called cybersickness. Cyber-sickness is the feeling of discomfort that occurs during VR experiences, producing symptoms similar to those of motion sickness. It continues to remain one of the biggest hurdles to the widespread adoption of VR, making it increasingly important to explore and understand the factors that influence its onset. In this work, we investigated the influence of the presence/absence of motion control on the onset and severity of cybersickness in an HMD based VR driving simulation employing steering as a travel metaphor. Towards this end, we conducted a between subjects study manipulating the presence of control between three experimental conditions, two of which (Driving condition and Yoked Pair condition) formed a yoked control design where every pair of drivers and their yoked pairs were exposed to identical vehicular motion stimuli created by participants in the driving condition. In the other condition (Autonomous Car condition), participants experienced a program driven autonomous vehicle simulation. Results indicated that participants in the Driving condition experienced higher levels of cybersickness than participants in the Yoked Pair condition. While these results don’t conform to findings from previous research which suggests that having control over motion reduces cybersickness, it seems to point towards the importance of the fidelity of the control metaphor’s feedback response in alleviating cybersickness. Simply allowing one control their motion may not readily alleviate cybersickness but could instead increase it in such HMD based VR driving simulations. It may hence be important to consider how well the control metaphor and its feedback matches users’ expectations if we want to successfully mitigate cybersickness.

The commercialization of Virtual Reality (VR) devices has made it easier for everyday users to experience VR from the comfort of their living rooms. This recent uptake in VR has also increased reported incidents of cybersickness. Cybersickness refers to the discomfort experienced by an individual while experiencing virtual environments. The symptoms are similar to those of motion sickness but are more disorienting in nature resulting in dizziness, blurred vision, etc. Cybersickness is currently one of the biggest hurdles to the widespread adoption of VR, and it is therefore critical to explore the factors that influence its onset. Towards this end, we present a proof of concept simulation to study cybersickness in highly realistic immersive virtual environments.

HTTP-based Adaptive Streaming (HAS) is the dominant Internet video streaming application. One specific HAS approach, Dynamic Adaptive Streaming over HTTP (DASH), is of particular interest, as it is a widely deployed, standardized implementation. Prior academic research has focused on networking and protocol issues, and has contributed an accepted understanding of the performance and possible performance issues in large deployment scenarios. Our work extends the current understanding of HAS by focusing directly on the impacts of choice of the video quality adaptation algorithm on end-user perceived quality. In congested network scenarios, the details of the adaptation algorithm determine the amount of bandwidth consumed by the application as well as the quality of the rendered video stream. HAS will lead to user-perceived changes in video quality due to intentional changes in quality video segments, or unintentional perceived quality impairments caused by video decoder artifacts such as pixelation, stutters, or short or long stalls in the rendered video when the playback buffer becomes empty. The HAS adaptation algorithm attempts to find the optimal solution to mitigate the conflict between avoiding buffer stalls and maximizing video quality. In this article, we present results from a user study that was designed to provide insights into “best practice guidelines” for a HAS adaptation algorithm. Our findings suggest that a buffer-based strategy might provide a better experience under higher network impairment conditions. For the two network scenarios considered, the buffer-based strategy is effective in avoiding stalls but does so at the cost of reduced video quality. However, the buffer-based strategy does yield a lower number of quality switches as a result of infrequent bitrate adaptations. Participants in buffer-based strategy do notice the drop in video quality causing a decrease in perceived QoE, but the perceived levels of video quality, viewer frustration, and opinions of video clarity and distortion are significantly worse due to artifacts such as stalls in capacity-based strategy. The capacity-based strategy tries to provide the highest video quality possible but produces many more artifacts during playback. The results suggest that player video quality has more of an impact on perceived quality when stalls are infrequent. The study methodology also contributes a unique method for gathering continuous quantitative subjective measure of user perceived quality using a Wii remote.

Every task we perform in our day-to-day lives requires us to make judgements about size, distance, depth, etc. The same is true for tasks in an immersive virtual environments (IVE). Increasingly, Virtual Reality (VR) applications are being developed for training and entertainment, many of which require the user to determining whether s/he can pass through an opening. Typically, people determine their ability to pass through an aperture by comparing the width of their shoulders to the width of the opening. Thus, judgments of size and distance in an IVE are necessary for accurate judgments of passability. In this experiment, we empirically evaluate how passability judgments in an IVE, viewed through a Head-Mounted Display (HMD), compare to judgments made in the real world. An exact to scale virtual replica of the room and apparatus was used for the VR condition. Results indicate that the accuracy of passability judgments seem to be comparable to the real world.

This paper details the results of an initial empirical evaluation conducted to examine how stereoscopic viewing and haptic feedback affects fine motor actions in a pick-and-place task, similar to the peg transfer task in an FLS training curriculum for laproscopic sugical training. In a between subjects experiment, we examined the effect of stereoscopic viewing and simulated tactile feedback during the fine motor actions of a participants' actions in the near field on the number of collisions and time to complete the task. We found that stereo and haptic feedback contributed to the effectiveness of task performance in different ways. Specifically, we found that the mean time to complete the trials was significantly higher in the abcense of tactile feedback as compared to when it was present, and the mean number of collisions was significantly higher in the presence of stereo as compared to when it was absent.

With costs of head-mounted displays (HMDs) and tracking technology decreasing rapidly, various virtual reality applications are being widely adopted for education and training. Hardware advancements have enabled replication of real-world interactions in virtual environments to a large extent, paving the way for commercial grade applications that provide a safe and risk-free training environment at a fraction of the cost. But this also mandates the need to develop more intrinsic interaction techniques and to empirically evaluate them in a more comprehensive manner. Although there exists a body of previous research that examines the benefits of selected levels of interaction fidelity on performance, few studies have investigated the constituent components of fidelity in a Interaction Fidelity Continuum (IFC) with several system instances and their respective effects on performance and learning in the context of a real-world skills training application. Our work describes a large between-subjects investigation conducted over several years that utilizes bimanual interaction metaphors at six discrete levels of interaction fidelity to teach basic precision metrology concepts in a near-field spatial interaction task in VR. A combined analysis performed on the data compares and contrasts the six different conditions and their overall effects on performance and learning outcomes, eliciting patterns in the results between the discrete application points on the IFC. With respect to some performance variables, results indicate that simpler restrictive interaction metaphors and highest fidelity metaphors perform better than medium fidelity interaction metaphors. In light of these results, a set of general guidelines are created for developers of spatial interaction metaphors in immersive virtual environments for precise fine-motor skills training simulations.