Doug A. Bowman

An evaluation of techniques for grabbing and manipulating remote objects in immersive virtual environments

Grabbing and manipulating virtual objects is an important user interaction for immersive virtual environments. We present implementations and discussion of six techniques which allow manipulation of remote objects. A user study of these techniques was performed which revealed their characteristics and deficiencies, and led to the development of a new class of techniques. These hybrid techniques provide distinct advantages in terms of ease of use and efficiency because they consider the tasks of grabbing and manipulation separately. CR Categories and Subject Descriptors: 1.3.7 [Computer Graphics] :Three-Dimensional Graphics and Realism - Virtual Reality; 1.3.6 [Computer Graphics]:Methodology and Techniques - Interaction Techniques.

An Introduction to 3-D User Interface Design

Three-dimensional user interface design is a critical component of any virtual environment (VE) application. In this paper, we present a broad overview of 3-D interaction and user interfaces. We discuss the effect of common VE hardware devices on user interaction, as well as interaction techniques for generic 3-D tasks and the use of traditional 2-D interaction styles in 3-D environments. We divide most user-interaction tasks into three categories: navigation, selection/manipulation, and system control. Throughout the paper, our focus is on presenting not only the available techniques but also practical guidelines for 3-D interaction design and widely held myths. Finally, we briefly discuss two approaches to 3-D interaction design and some example applications with complex 3-D interaction requirements. We also present an annotated online bibliography as a reference companion to this article.

A survey of usability evaluation in virtual environments: classification and comparison of methods

Virtual environments (VEs) are a relatively new type of humancomputer interface in which users perceive and act in a three-dimensional world. The designers of such systems cannot rely solely on design guidelines for traditional two-dimensional interfaces, so usability evaluation is crucial for VEs. This paper presents an overview of VE usability evaluation to organize and critically analyze diverse work from this field. First, we discuss some of the issues that differentiate VE usability evaluation from evaluation of traditional user interfaces such as GUIs. We also present a review of some VE evaluation methods currently in use, and discuss a simple classification space for VE usability evaluation methods. This classification space provides a structured means for comparing evaluation methods according to three key characteristics: involvement of representative users, context of evaluation, and types of results produced. Finally, to illustrate these concepts, we compare two existing evaluation approaches: testbed evaluation (Bowman, Johnson, & Hodges, 1999) and sequential evaluation (Gabbard, Hix, & Swan, 1999).

Testbed Evaluation of Virtual Environment Interaction Techniques

As immersive virtual environment (VE) applications become more complex, it is clear that we need a firm understanding of the principles of VE interaction. In particular, designers need guidance in choosing three-dimensional interaction techniques. In this paper, we present a systematic approach, testbed evaluation, for the assessment of interaction techniques for VEs. Testbed evaluation uses formal frameworks and formal experiments with multiple independent and dependent variables to obtain a wide range of performance data for VE interaction techniques. We present two testbed experiments, covering techniques for the common VE tasks of travel and object selection/manipulation. The results of these experiments allow us to form general guidelines for VE interaction and to provide an empirical basis for choosing interaction techniques in VE applications. Evaluation of a real-world VE system based on the testbed results indicates that this approach can produce substantial improvements in usability.

Move to improve: promoting physical navigation to increase user performance with large displays

In navigating large information spaces, previous work indicates potential advantages of physical navigation (moving eyes, head, body) over virtual navigation (zooming, panning, flying). However, there is also indication of users preferring or settling into the less efficient virtual navigation. We present a study that examines these issues in the context of large, high resolution displays. The study identifies specific relationships between display size, amount of physical and virtual navigation, and user task performance. Increased physical navigation on larger displays correlates with reduced virtual navigation and improved user performance. Analyzing the differences between this study and previous results helps to identify design factors that afford and promote the use of physical navigation in the user interface.

Formalizing the Design, Evaluation, and Application of Interaction Techniques for Immersive Virtual Environments

Immersive virtual environments (VEs) have potential in many application areas, but many complex VE systems exhibit usability and interaction problems. This is partly due to a lack of consideration or understanding of 3D interaction tasks and techniques. This paper proposes the systematic study of the design, evaluation, and application of VE interaction techniques. In this methodology, design and evaluation are based on a formal task analysis and categorization of techniques, using multiple performance measures. As a direct consequence of our use of this methodology, we also present a variety of novel designs and evaluation results with respect to interaction techniques for three common VE tasks. ( 1999 Academic Press

Design and evaluation of menu systems for immersive virtual environments

Interfaces for system control tasks in virtual environments (VEs) have not been extensively studied. The paper focuses on various types of menu systems to be used in such environments. We describe the design of the TULIP menu, a menu system using Pinch Gloves/sup TM/, and compare it to two common alternatives: floating menus and pen and tablet menus. These three menus were compared in an empirical evaluation. The pen and tablet menu was found to be significantly faster, while users had a preference for TULIP. Subjective discomfort levels were also higher with the floating menus and pen and tablet.

The Simple Virtual Environment Library: An Extensible Framework for Building VE Applications

As virtual environment (VE) technology becomes accessible to (and affordable for) an ever-widening audience of users, the demand for VE applications will increase. Tools that assist and facilitate the development of these applications, therefore, will also be in demand. To support our efforts in quickly designing and implementing VE applications, we have developed the Simple Virtual Environment (SVE) library. In this article, we describe the characteristics of the library that support the development of both simple and complex VE applications. Simple applications are created by novice programmers or for rapid prototyping. More-complex applications incorporate new user input and output devices, as well as new techniques for user interaction, rendering, or animation. The SVE library provides more-comprehensive support for developing new VE applications and better supports the various device configurations of VE applications than current systems for 3-D graphical applications. The development of simple VE applications is supported through provided default interaction, rendering, and user input and output device handling. The librarys framework includes an execution framework that provides structure for incrementally adding complexity to selected tasks of an application, and an environment model that provides a layer of abstraction between the application and the device configuration actually used at runtime. This design supports rapid development of VE applications through incremental development, code reuse, and independence from hardware resources during the development.

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).

The Educational Value of an Information-Rich Virtual Environment

Information-rich virtual environments consist not only of three-dimensional graphics and other spatial data but also information of an abstract or symbolic nature that is related to the space. An environment of this type can stimulate learning and comprehension, because it provides a tight coupling between symbolic and experiential information. In our virtual zoo exhibit, students can explore an accurate model of the gorilla habitat at Zoo Atlanta and access information related to the design of the exhibit. This paper discusses the design of the application and the interaction techniques used to obtain information. We also present the results of a formal evaluation. Although no statistically significant differences were found, results indicate that students who used the virtual environment had higher test scores than those who only attended a lecture on the material. Trends suggest that the virtual experience allowed students to learn information directly and also equipped them to better learn and understand material from a traditional lecture.