Rudolph P. Darken

Navigating large virtual spaces

As important as navigation is to human performance in virtual worlds, it is an often overlooked problem in the design process. This article reports an experiment intended to show that real‐world wayfinding and environmental design principles are effective in designing virtual worlds that support skilled wayfinding behavior. The study measures participant performance on a complex searching task in a number of virtual worlds with differing environmental cues. The worlds are augmented with either a radial grid, a map, or both a grid and a map. The control condition provided no additional navigational cues. The results showed that navigational performance was superior under both map treatments as compared to the control and grid conditions. The grid was, however, shown to provide superior directional information as compared to the other conditions. The control condition provided the worst performance, with participants often becoming disoriented and experiencing extreme difficulty completing the tasks.

The omni-directional treadmill: a locomotion device for virtual worlds

The Omni-Directional Treadmill (ODT) is a revolutionary device for locomotion in large-scale virtual environments. The device allows its user to walk or jog in any direction of travel. It is the third generation in a series of devices built for this purpose for the U.S. Army’s Dismounted Infantry Training Program. We first describe the device in terms of its construction and operating characteristics. We then report on an analysis consisting of a series of locomotion and maneuvering tasks on the ODT. We observed user motions and system responses to those motions from the perspective of the user. Each task is described in terms of what causes certain motions to trigger unpredictable responses causing loss of balance or at least causing the user to become consciously aware of their movements. We conclude that the two primary shortcomings in the ODT are its tracking system and machine control mechanism for centering the user on the treads.

Map usage in virtual environments: orientation issues

Navigation tasks in large virtual environments often call for the use of a virtual map. However, all maps are not alike. Performance on navigation tasks in general has been shown to vary depending on the orientation of the map with respect to the users frame of reference. This paper reports the results of an experiment investigating orientation issues of virtual maps for use during navigation tasks. Participants were given a virtual map in either a north-up or forward-up configuration. Performance on search tasks was measured in terms of search time and errors. Results indicate that targeted search tasks (tasks requiring only the egocentric reference frame) are best served by a forward-up alignment while primed and naive search tasks (tasks requiring information from the world reference frame) prefer a north-up alignment. Both types of maps are affected by the ability of user to perform mental rotations.

Spatial Orientation and Wayfinding in Large-Scale Virtual Spaces: An Introduction

‘‘I have coasted this lake, in search of skins, afore the war, and have been here already; not at this very spot, for we landed yonder, where you may see the oak that stands above the cluster of hemlocks.’’ ‘‘How, Pathfinder, can you remember all these trifles so accurately?’’ ‘‘These are our streets and houses—our churches and palaces. Remember them, indeed! . . .’’ The Pathfinder, James Fenimore Cooper (1840)

Navigating in natural environments: a virtual environment training transfer study

The ability to use virtual environments as either an abstraction of a space, similar to a map, or as a simulation of the space itself has suggested to many that it would be a useful tool in terrain familiarization of unknown environments. Up to this point, all research in this area has focused on building interiors and urban environments which are significantly different from natural environments in terms of navigation cues and useful wayfinding techniques. The experiment we present uses a virtual environment, as compared to a map only or real-world conditions on navigation tasks in a natural environment. We show that navigation ability is more important to performance than the training method, with the virtual environment being most effective for intermediate orienteers as compared to advanced or beginner orienteers.

Wayfinding in large-scale virtual worlds

The spatial nature of large-scale virtual worlds introduces wayfinding problems which are often overlooked in the design process. In order to design and build useful virtual worlds in which real work can take place, these issues must be addressed. The research described here is a study of human wayfinding in virtual worlds and how real world solutions can be applied to virtual world design. The objective of this work is to develop design principles which will lead to a design methodology for virtual worlds in which wayfinding problems are alleviated.

Delta3D: a complete open source game and simulation engine for building military training systems

Delta3D, the open source game and simulation engine built for military training, is continuing to be improved to meet the requirements of the military users. The most recent upgrades, available in versions 1.4 and later, include adding capability for After Action Review, integration with SCORM-compliant learning management systems (LMSs), and distributed interactive simulation (DIS) networking. Additionally, more applications, created by both government users and civilian companies, continue to be built using Delta3D and its expanding capabilities With these added features, Delta3D has become the engine of choice for several military simulations, including programs of record. The developers and program managers of these programs were attracted by its advanced technical features, its lack of proprietary vendor lock-in and licensing fees, and the ability to quickly produce sophisticated applications using Delta3D. This paper discusses the current state of Delta3D version 1.4 and how developers and program managers can use Delta3D to quickly and cheaply build complex training systems. It will also briefly touch upon the systems currently being built using Delta3D and how some of these have been proven to work in a training environment. It will also discuss what improvements to the engine will be added in the near future.

Mixed-dimension interaction in virtual environments

In this paper, we present a study to show that matching the dimensionality of interaction techniques with the dimensional demands of the task results in an interface that facilitates superior performance on interaction tasks without sacrificing performance on 2D tasks in favor of 3D tasks and vice versa. We describe the concept of dimensional congruence and how to identify the dimensional characteristics of a task so that appropriate interaction techniques can be applied. We constructed a prototypical application in a Virtual Environment Enclosure (VEE) using a hand-held device to show how this might be done in this type of apparatus. We then describe a study that evaluates both 2D and 3D tasks as performed using typical 2D and 3D interaction techniques. Results show that an appropriate mix of 2D and 3D interaction techniques is preferred over exclusive use of one or the other. The challenge lies not in selecting independent interaction techniques for specific tasks, but rather in constructing an overall interface that mixes 2D and 3D interactions appropriately.

Spatial Orientation and Wayfinding in Large-Scale Virtual Spaces II: Guest Editors' Introduction

Few things are as fundamental to the human experience as the interaction between humans and their environment—be it physical or virtual. A critical element of this interaction involves movement through space. We know that what we often refer to as navigation is not merely physical translation through a space, termed locomotion or travel, but that there is also a cognitive element, often referred to as wayfinding, that involves issues such as mental representations, route planning, and distance estimation. This collection of articles addresses issues related to both the physical and the cognitive aspects of navigation as well as theoretical models that bind them together.

A Validation Methodology for Human Behavior Representation Models

The Department of Defense (DoD) relies heavily on mathematical models and computer simulations to analyze and acquire new weapon systems. Models and simulations help decision makers understand the differences between systems and provide insights into the implications of weapon system tradeoffs. Given this key role, the credibility of simulations is paramount. For combat models, this is gained through the verification, validation, and accreditation process required of DoD analytical models prior to their use in weapon systems acquisition and other studies. The nature of nondeterministic human behavior makes validation of models of human behavior representation contingent on the judgments of subject matter experts that are routinely acquired using a face validation methodology. In an attempt to better understand the strengths and weaknesses of assessing human behavior representation using experts and the face validation methodology, the authors conducted experiments to identify issues critical to utilizing human experts for the purpose of ascertaining ways to enrich the validation process for models relying on human behavior representation. The research was limited to the behaviors of individuals engaged in close combat in an urban environment. This paper presents the study methodology, data analysis, and recommendations for mitigating attendant problems with validation of human behavior representation models.