Ryan P. McMahan

Evaluating Display Fidelity and Interaction Fidelity in a Virtual Reality Game

In recent years, consumers have witnessed a technological revolution that has delivered more-realistic experiences in their own homes through high-definition, stereoscopic televisions and natural, gesture-based video game consoles. Although these experiences are more realistic, offering higher levels of fidelity, it is not clear how the increased display and interaction aspects of fidelity impact the user experience. Since immersive virtual reality (VR) allows us to achieve very high levels of fidelity, we designed and conducted a study that used a six-sided CAVE to evaluate display fidelity and interaction fidelity independently, at extremely high and low levels, for a VR first-person shooter (FPS) game. Our goal was to gain a better understanding of the effects of fidelity on the user in a complex, performance-intensive context. The results of our study indicate that both display and interaction fidelity significantly affect strategy and performance, as well as subjective judgments of presence, engagement, and usability. In particular, performance results were strongly in favor of two conditions: low-display, low-interaction fidelity (representative of traditional FPS games) and high-display, high-interaction fidelity (similar to the real world).

Questioning naturalism in 3D user interfaces

3D UIs are uniquely able to achieve superior interaction fidelity, and this naturalism can be a huge advantage.

Separating the effects of level of immersion and 3D interaction techniques

Empirical evidence of the benefits of immersion is an important goal for the virtual environment (VE) community. Direct comparison of immersive systems and non-immersive systems is insufficient because differences between such systems may be due not only to the level of immersion, but also to other factors, such as the input devices and interaction techniques used. In this paper, a study is presented that separates the effects of level of immersion and 3D interaction technique for a six-degree-of-freedom manipulation task. In the study, two components of immersion -- stereoscopy and field of regard -- were varied and three 3D interaction techniques -- HOMER, Go-Go, and DO-IT (a new keyboard- and mouse-based technique) -- were tested. The results of the experiment show that the interaction technique had a significant effect on object manipulation time, while the two components of immersion did not. The implications of these results are discussed for VE application developers.

Evaluating natural interaction techniques in video games

Despite the gaming industrys recent trend for using “natural” interaction techniques, which mimic real world actions with a high level of fidelity, it is not clear how natural interaction techniques affect the player experience. In order to obtain a better understanding, we designed and conducted a study using Mario Kart Wii, a commercial racing game for the Nintendo Wii. We chose this platform due to its seemingly balanced design of both natural and non-natural interaction techniques. Our empirical study of these techniques found that the non-natural interaction techniques significantly outperform their more natural counterparts. We offer three hypotheses to explain our finding and suggest them as important interaction design considerations.

Considerations for the use of commercial video games in controlled experiments

While commercial, off-the-shelf video games have been used often to observe cognitive and social phenomena, few studies have taken advantage of such games as research tools for conducting controlled experiments. Providing evidence that unmodified, commercial video games can be used to conduct gaming evaluations with high levels of both experimental control and ecological validity, we designed and conducted an experiment that utilized Mario Kart Wii to evaluate the effects of natural interaction on player performance. Based on our experience from that experiment, we present several concerns that require attention when using commercial video games as research tools. Providing examples of design decisions and outcomes from our experiment, we identify some of the benefits, drawbacks, and challenges of using such tools.

Effects of Field of View and Visual Complexity on Virtual Reality Training Effectiveness for a Visual Scanning Task

Virtual reality training systems are commonly used in a variety of domains, and it is important to understand how the realism of a training simulation influences training effectiveness. We conducted a controlled experiment to test the effects of display and scenario properties on training effectiveness for a visual scanning task in a simulated urban environment. The experiment varied the levels of field of view and visual complexity during a training phase and then evaluated scanning performance with the simulators highest levels of fidelity and scene complexity. To assess scanning performance, we measured target detection and adherence to a prescribed strategy. The results show that both field of view and visual complexity significantly affected target detection during training; higher field of view led to better performance and higher visual complexity worsened performance. Additionally, adherence to the prescribed visual scanning strategy during assessment was best when the level of visual complexity during training matched that of the assessment conditions, providing evidence that similar visual complexity was important for learning the technique. The results also demonstrate that task performance during training was not always a sufficient measure of mastery of an instructed technique. That is, if learning a prescribed strategy or skill is the goal of a training exercise, performance in a simulation may not be an appropriate indicator of effectiveness outside of training-evaluation in a more realistic setting may be necessary.

Shadow walking: An unencumbered locomotion technique for systems with under-floor projection

When viewed from below, a users feet cast shadows onto the floor screen of an under-floor projection system, such as a six-sided CAVE. Tracking those shadows with a camera provides enough information for calculating a users ground-plane location, foot orientation, and footstep events. We present Shadow Walking, an unencumbered locomotion technique that uses shadow tracking to sense a users walking direction and step speed. Shadow Walking affords virtual locomotion by detecting if a user is walking in place. In addition, Shadow Walking supports a sidestep gesture, similar to the iPhones pinch gesture. In this paper, we describe how we implemented Shadow Walking and present a preliminary assessment of our new locomotion technique. We have found Shadow Walking provides advantages of being unencumbered, inexpensive, and easy to implement compared to other walking-in-place approaches. It also has potential for extended gestures and multi-user locomotion.

Development of a Simple and Low-Cost Olfactory Display for Immersive Media Experiences

Olfaction is an important perceptual function that is often neglected in immersive media (IM) and virtual reality (VR) applications. Because the effects of olfaction have not been researched as much as those of visual, auditory, or haptic senses, the effects of olfactory stimuli on IM experiences are mainly unexplored, largely unknown, and debatable in many examples. A major factor limiting olfaction research is the lack of olfactory display options. Commercial solutions are often inadequate and expensive. Prior research on olfactory displays is helpful, but pertinent details are normally missing, and the devices are often too complex to replicate. To address this issue, we have developed a simple, low-cost olfactory display by using inexpensive components and leveraging airflow for vaporization and scent delivery. In this paper, we detail the development of our display and describe an informal study evaluating its effectiveness.

Development of a low-cost tactile sleeve for autism intervention

Autism Spectrum Disorder (ASD) is a pervasive disorder that can cause sensory-perceptual anomalies, such as a hypersensitivity to contact with other people. We have designed and developed a tactile sleeve to help ASD patients potentially learn how to manage hypersensitivities to human contact through virtual experiences of being touched. Our tactile sleeve simulates both simple and dynamic social touches on the upper arm of the user. These touch gestures are perceived from phantom tactile sensations and apparent tactile motions that are generated by a rectangular grid of vibrotactile actuators. Our design requirements for the sleeve included being inexpensive to produce and integrable with prior ASD intervention software. We describe our formative process for developing the sleeve and conclude with details of our final prototype.

A reproducible olfactory display for exploring olfaction in immersive media experiences

Olfaction, the sense of smell, is an important perceptual function. It has been shown to enhance the quality of life and to facilitate memory recall. However, despite its importance and potential benefits, olfaction is often neglected when creating immersive media experiences (IMEs). The probable reason is that olfactory displays are not readily available. We have developed a reproducible olfactory display that is simple and affordable to make olfactory displays more available. More importantly, we have conducted three exploratory studies on the effects of olfaction. The results of these studies indicate that olfaction is a nuanced sense that can have both positive and negative effects on user experiences. Hence, further research is needed to better understand and design for olfaction in IMEs.