Desktop Virtual Environment Research Articles

A comparison of guidance cues in desktop virtual environments

Designers of educational and entertainment desktop virtual environments (VEs) have employed a variety of cues for motivating users to perform actions or adopt particular viewpoints. However, there has been little formal study comparing user responses to such cues. This paper reports the results of a preliminary study of five cues (agents, signs, man-made landmarks, environmental landmarks, and trails) for motivating actions in virtual environments. Given a sample task of navigating to a target destination, no significant differences between the cues were observed in terms of overall success or speed. However, significant differences between the cues were found on other measures, including minimization of detours (trails) and awareness of guidance (agents, signs, trails). Frequency of desktop VE usage was also found to influence performance.

Special issue on ‘Interacting with desktop virtual environments: Perception and navigation’

Special issue on ‘Interacting with desktop virtual environments: Perception and navigation’

Navigational tools for desktop virtual environment interfaces

Desktop systems typically rely on a two-dimensional (2D) software interface and general purpose hardware (mouse, keyboard) for interaction with a three-dimensional (3D) virtual environment. These interfaces must provide all the functionality required to navigate through and interact with the virtual environment, yet research into the usability aspects of the tools presented on these software interfaces indicates that the majority of users experience some degree of frustration when using them to perform even relatively simple tasks. This paper begins with a study of usability issues for interfaces to virtual environments on desktop systems, and details a series of experiments performed to evaluate the usability of a number of navigational tools. Participants were tested on the time taken to complete a number of navigational tasks with a series of interfaces presenting different navigational tools. The tools presented were a speed control function, a you-are-here (YAH) map, a function enabling the user to mark and teleport to any location within the presented environment, and an undo function. Results indicate that the visual presentation of navigational aids improves navigation performance, in terms of the time taken to complete tasks, and also improves user satisfaction with the desktop system.

Navigation in desktop virtual environments: an evaluation and recommendations for supporting usability

Virtual reality (VR) can provide useful tools for a variety of applications. However, for these tools to be effective, they must be easy to use. In virtual environments (VEs), usability is impaired by poorly designed navigation systems. Insufficient realism and missing physiological orientation and motion cues impair spatial learning in desktop VEs. Capabilities for navigation in a VE are far more varied than in reality; so much greater flexibility can be offered, but designing VEs with too many options can overwhelm users. To assist designers in building effective, usable navigation systems for VEs, navigation techniques must be evaluated to identify which features actually support users in accomplishing their tasks and which features create unnecessary problems.This study evaluates navigation in two different VEs to develop recommendations for the design of navigation systems in desktop VEs. The study consists of an objective assessment of navigation control dynamics, a guideline-based evaluation and a review of data collected during two experimental studies. The findings indicate that real-world constraints, specialised navigation techniques and feedback regarding location and direction of travel are needed to support navigation in desktop VEs.

Anticipating action in complex scenes

In four experiments we explored the accuracy of memory for human action using displays with continuous motion. In Experiment 1, a desktop virtual environment was used to visually simulate ego‐motion in depth, as would be experienced by a passenger in a car. Using a task very similar to that employed in typical studies of representational momentum we probed the accuracy of memory for an instantaneous point in space/time, finding a consistent bias for future locations. In Experiment 2, we used the same virtual environment to introduce a new “interruption” paradigm in which the sensitivity to displacements during a continuous event could be assessed. Thresholds for detecting displacements in ego‐position in the direction of motion were significantly higher than those opposite the direction of motion. In Experiments 3 and 4 we extended previous work that has shown anticipation effects for frozen action photographs or isolated human figures by presenting observers with short video sequences of complex crowd scenes. In both experiments, memory for the stopping position of the video was shifted forward, consistent with representational momentum. Interestingly, when the video sequences were played in reverse, the magnitude of this forward bias was larger. Taken together, the results of all four experiments suggest that even when presented with complex, continuous motion, the visual system may sometimes try to anticipate the outcome of our own and others' actions.

Interaction with a desktop virtual environment: a 2D view into a 3D world

With the development of computer software and hardware in the past few years, it has been possible to produce effective training virtual environments on everyday personal computers with little expert training required for users or designers. However, the development of the equipment that enables this has brought little coinciding research on what features to include when designing these environments. Despite these increased advances in PC capabilities for desktop virtual environments (VEs), there are still limitations on the number of objects that can be programmed to be interactive, usually due to restrictions on programming time and cost. As a result, it is often left to the programmer to decide which of the objects included to increase the realism of the environment will be interactive and which aesthetic. The work presented in this paper is an experiment that aims to establish a guide for environment designers to aid effective environment interaction development by identifying key elements in a VE design.

Design and display of enhancing information in desktop information-rich virtual environments: challenges and techniques

Information-rich virtual environments (IRVEs) have been described as environments in which perceptual information is enhanced with abstract (or symbolic) information, such as text, numbers, images, audio, video, or hyperlinked resources. Desktop virtual environment (VE) applications present similar information design and layout challenges as immersive VEs, but, in addition, they may also be integrated with external windows or frames commonly used in desktop interfaces. This paper enumerates design approaches for the display of enhancing information both internal and external to the virtual world’s render volume. Using standard Web-based software frameworks, we explore a number of implicit and explicit spatial layout methods for the display and linking of abstract information, especially text. Within the VE view, we demonstrate both heads-up-displays (HUDs) and encapsulated scenegraph behaviors we call semantic objects. For desktop displays, which support information display venues external to the scene, we demonstrate the linking and integration of the scene with Web browsers and external visualization applications. Finally, we describe the application of these techniques in the PathSim visualizer, an IRVE interface for the biomedical domain. These design techniques are relevant to instructional and informative interfaces for a wide variety of VE applications.

Evaluating design guidelines for reducing user disorientation in a desktop virtual environment

Navigation in virtual environments can be difficult. One contributing factor is user disorientation. Two major causes of this are the lack of navigation cues in the environment and problems with navigating too close to or through virtual world objects. Previous work has developed guidelines, informed by cinematography conventions, for the construction of virtual environments to aid user comprehension of virtual space to reduce user disorientation. To validate these guidelines, two user studies have been performed where users of a desktop virtual environment are to complete a navigation task in a virtual maze. In an initial study [12], collision detection with the maze walls was not enabled and the results indicated that the guidelines were effective for reducing disorientation but not for developing the user’s awareness of the environment space. A second study has been performed where collision detection was enabled. Results suggest that the use of the guidelines can help reduce the incidences of user disorientation and aid navigation tasks. However, the guidelines have little impact on users’ ability to construct cognitive maps of the desktop virtual environment.

Using virtual environments to assess directional knowledge

Computer-simulated (virtual) environments offer several potential advantages over traditional means (e.g. paper and pencil tests) of assessing people's spatial knowledge of large-scale environments. We examined the relative accuracy and precision with which people estimated directions among unseen landmarks in a large familiar environment using five different methods. People estimated directions (1) in the real environment, (2) in an immersive virtual environment, (3) in a desktop virtual environment, (4) using a static visual image of the environment, and (5) using a traditional paper and pencil assessment technique. Direction estimates were more accurate and more precise in the first three conditions than in the other conditions. Errors and variances were highly correlated among the first three conditions but were not correlated among the other conditions. Direction estimates in the paper and pencil condition were affected by a response bias that has not been adequately addressed in prior literature.

Vertigo in Virtual Reality with Haptics: Case Report

A researcher was working with a desktop virtual environment system. The system was displaying vector fields of a cyclonic weather system, and the system incorporated a haptic display of the forces in the cyclonic field. As the subject viewed the rotating cyclone field, they would move a handle "through" the representation of the moving winds and "feel" the forces buffeting the handle as it moved. Stopping after using the system for about 10 min, the user experienced an immediate sensation of postural instability for several minutes. Several hours later, there was the onset of vertigo with head turns. This vertigo lasted several hours and was accompanied with nausea and motion illusions that exacerbated by head movements. Symptoms persisted mildly the next day and were still present the third and fourth day, but by then were only provoked by head movements. There were no accompanying symptoms or history to suggest an inner ear disorder. Physical examination of inner ear and associated neurologic function was normal. No other users of this system have reported similar symptoms. This case suggests that some individuals may be susceptible to the interaction of displays with motion and movement forces and as a result experience motion illusions. Operators of such systems should be aware of this potential and minimize exposure if vertigo occurs.

Construction of feature-matching perception in virtual assembly

An important characteristic of virtual assembly is interaction. Traditional direct manipulation in virtual assembly relies on dynamic collision detection, which is very time-consuming and even impossible in desktop virtual assembly environment. Feature-matching is a critical process in harmonious virtual assembly, and is the premise of assembly constraint sensing. This paper puts forward an active object-based feature-matching perception mechanism and a feature-matching interactive computing process, both of which make the direct manipulation in virtual assembly break away from collision detection. They also help to enhance virtual environment understandability of user intention and promote interaction performance. Experimental results show that this perception mechanism can ensure that users achieve real-time direct manipulation in desktop virtual environment.

Visitor-Oriented Design-Three Studies of Visitor Accommodation and a Call for Action

This article proposes and describes a visitor-oriented perspective emphasizing the unique needs of visitors of digital environments in contrast to the user-oriented perspective that emphasizes the needs of users. To do so, the term accommodation is introduced in a technical sense and given a brief explanation. Results are also reported from 3 explorative studies of desktop virtual reality environments. In these studies, the visitor-oriented perspective was adopted and allowed for analyzing how participants perceived the environments as places rather than artifacts for use. In comparison to a web site, it was found that even a rudimentary virtual reality environment can have a positive impact on visitor regard for information content. Implementing teleports increased the efficiency of 1 test environment, but it was not found to have a positive effect on user attitudes to the environment. Many participants felt that the environments were sterile. Another common complaint was about the amount of walking required in the first environment. Five suggestions are given for building desktop virtual reality environments that are better received by visitors. In closing, the visitor-oriented perspective presented here is briefly discussed in relation to Winograd and Taber's (1997) writings on software inhabitants.

A fuzzy controller with supervised learning assisted reinforcement learning algorithm for obstacle avoidance

Fuzzy logic systems are promising for efficient obstacle avoidance. However, it is difficult to maintain the correctness, consistency, and completeness of a fuzzy rule base constructed and tuned by a human expert. A reinforcement learning method is capable of learning the fuzzy rules automatically. However, it incurs a heavy learning phase and may result in an insufficiently learned rule base due to the curse of dimensionality. In this paper, we propose a neural fuzzy system with mixed coarse learning and fine learning phases. In the first phase, a supervised learning method is used to determine the membership functions for input and output variables simultaneously. After sufficient training, fine learning is applied which employs reinforcement learning algorithm to fine-tune the membership functions for output variables. For sufficient learning, a new learning method using a modification of Sutton and Barto's model is proposed to strengthen the exploration. Through this two-step tuning approach, the mobile robot is able to perform collision-free navigation. To deal with the difficulty of acquiring a large amount of training data with high consistency for supervised learning, we develop a virtual environment (VE) simulator, which is able to provide desktop virtual environment (DVE) and immersive virtual environment (IVE) visualization. Through operating a mobile robot in the virtual environment (DVE/IVE) by a skilled human operator, training data are readily obtained and used to train the neural fuzzy system.

An Investigation of Visual Cues used to Create and Support Frames of Reference and Visual Search Tasks in Desktop Virtual Environments

Visual depth cues are combined to produce the essential depth and dimensionality of Desktop Virtual Environments (DVEs). This study discusses DVEs in terms of the visual depth cues that create and support perception of frames of references and accomplishment of visual search tasks. This paper presents the results of an investigation that identifies the effects of the experimental stimuli positions and visual depth cues: luminance, texture, relative height and motion parallax on precise depth judgements made within a DVE. Results indicate that the experimental stimuli positions significantly affect precise depth judgements, texture is only significantly effective for certain conditions, and motion parallax, in line with previous results, is inconclusive to determine depth judgement accuracy for egocentrically viewed DVEs. Results also show that exocentric views, incorporating relative height and motion parallax visual cues, are effective for precise depth judgements made in DVEs. The results help us to understand the effects of certain visual depth cues to support the perception of frames of references and precise depth judgements, suggesting that the visual depth cues employed to create frames of references in DVEs may influence how effectively precise depth judgements are undertaken.

Investigating Distance Knowledge Using Virtual Environments

Computer-simulated three-dimensional environments have become a popular tool in spatial cognition research. One way of demonstrating their usefulness is to replicate experimental results obtained in physical spaces. Two experiments investigated the role of environmental features in distance cognition, following Sadalla and Magel. Their participants explored routes marked with tape on the floor through active walking. Results showed that a higher number of turns along a route increased the estimated length of that route. In the authors’experiments, participants had to explore the routes in a desktop virtual environment. Experiment 1 employed ratio estimation and drawing methods and replicated Sadalla and Magel’s findings. Experiment 2 employed a reproduction method, and extends the results by showing that relative to physical distance, the route with fewer turns was underestimated, while the route with more turns was overestimated. The results show that desktop virtual environments are a valid and economic research tool.

How tutors assist adults with learning disabilities to use virtual environments

Purpose : To describe strategies used by tutors teaching adults with learning disabilities to use desktop virtual environments and to investigate their effectiveness by examining changes over time in tutor and learner behaviour. Method : Twenty adults with learning disabilities spent 12 sessions with one of four non-disabled tutors learning to use desktop virtual environments designed to teach independent living skills. Sessions were recorded on videotape, categories of behaviour were described and tapes analysed for frequency of tutor behaviours and goals achieved by learners. Results : Tutor strategies were described in terms of whether they aimed to help the learner master the interaction devices or to navigate and achieve goals in the virtual environments and how directive they were. There were some differences between tutors but this did not relate to whether tutors were experienced users themselves of the environments or were initially unfamiliar with them. Goal achievement was maintained at a constant level while help with the interaction devices and specific information about the environment decreased over repeated sessions. Rates of non-specific information did not change. Conclusions : Pretraining with the interaction devices would free both tutor and learner to concentrate on achieving goals in the environments. Much of the specific help given by the tutor could be incorporated into the software.

Using desktop virtual environments to investigate the role of landmarks

Recent research on spatial cognition has used computer-simulated three dimensional environments to create appropriate laboratory settings when trying to examine processes of spatial orientation. One way to evaluate “virtual environments” is to replicate results of experiments which were originally conducted in traditional laboratory or in real world settings. The experiment which is reported here investigates the role of landmarks when acquiring route knowledge in a system of paths. The design follows an earlier experiment by Cohen and Schuepfer [ Child development 31 (1980) 1065]. It can be shown, that landmarks play an important role in the system of paths: landmarks which are combined with turns towards the destination are more likely to become strategic nodes in the network than those which are not connected. Beside these results, a software designed to build appropriate environments is shown and its usability is demonstrated. The use of virtual environments provides both economical and flexible design of realistic experimental settings, as well as a valide recording of behavior.

Movement in Cluttered Virtual Environments

Imagine walking around a cluttered room but then having little idea of where you have traveled. This frequently happens when people move around small virtual environments (VEs), searching for targets. In three experiments, participants searched small-scale VEs using different movement interfaces, collision response algorithms, and fields of view. Participants' searches were most efficient in terms of distance traveled, time taken, and path followed when the simplest form of movement (view direction) was used in conjunction with a response algorithm that guided (“slipped”) them around obstacles when collisions occurred. Unexpectedly, and in both immersive and desktop VEs, participants often had great difficulty finding the targets, despite the fact that participants could see the whole VE if they stood in one place and turned around. Thus, the trivial real-world task used in the present study highlights a basic problem with current VE systems.

Page 18 using diversity modeling for instructional design

This article describes the use of diversity modeling to redesign a human-centered environment in which to teach physics concepts to high school students who have learning disabilities. The designers used performance-centered design techniques to precisely identify performers and to provide them with the best combination of knowledge objects, artifacts, and built-in support for their performance needs. A Steppingstones to Technology Grant from the U.S. Department of Education provided the funding for Project DEVISE (Designing Environments for Virtually Immersive Science Education), which creates desktop virtual reality environments, called Motion Magic, in which students can explore Newton's Laws of Motion. Because the goal of these environments is to teach high school students with learning disabilities about difficult science concepts, it was especially important that designers understand the performers and their needs. By developing diversity models and using them as design tools, program designers were able to focus on the needs of archetypal performers to develop more relevant interaction designs.

Spatial representations of virtual mazes: the role of visual fidelity and individual differences.

Twenty-four people learned three versions of a room-sized maze: a wire-frame desktop virtual environment (VE), a normal surface-rendered desktop VE, and a real-world maze. Differences among the mental representations formed from each environment were measured with pointing and distance estimation tasks in a real-world version of each maze. People were more accurate at pointing after having learned the real and wire-frame VE maze than the surface-rendered VE maze; however, this effect was small compared with the effect of individual differences. Differences in gender, spatial ability, and prior computer experience were significantly related to the ability to acquire spatial information from the desktop VE. There was a high correlation between spatial knowledge when it was measured in the VE and spatial knowledge measured in the real world. Actual or potential applications include the design of effective VE training systems.