Mariner—A 3-Dimensional Navigation Language

In recent years, virtual reality (VR) has become an increasingly powerful and inexpensive tool for developing interfaces for a variety of applications. Even though there has been an increase in the use of virtual reality (VR), there is a lack of software that bridges the gap between existing application programs and VR. This type of middleware is needed to manage the navigational interaction between existing application programs and VR. This article describes a language for describing navigation behaviors in 3-dimensional worlds that could potentially serve as middleware. The formal language described in this article permits precise navigation path specification and can be used as the means of mediation with application programs. The language can be used in achieving tasks such as exploring virtual worlds, programming the navigation and routing strategies for avatars, simulating the trajectories of virtual objects, and providing a formal description language for documenting user navigation in VR environments. ********** In recent years, virtual reality (VR) has become an increasingly powerful and inexpensive tool for developing interfaces to applications such as architectural modeling, computer-aided design, data visualization, telecommuting, and environments for simulation and entertainment. Interaction in applications that incorporate VR as an interface is dynamic by nature. Users immerse themselves in 3-dimensional (3D) environments using specialized peripheral devices including head-mounted displays, data gloves, 3D-trackers, and body suits. These devices enable users to experience rich stimuli and give them control over where they go and what they do within the confines of an application. This freedom is enabled by the ability to navigate in the world. Navigation is an aspect of behavior that causes an object to change its location, orientation, and/or relationship to other objects in its environment (Matsuba & Roehl, 1996). User interface designers have previously investigated navigation in 2-dimensional (2D) spaces and developed design principles that guide them in the development of effective and efficient interfaces (Beasley & Vila, 1992; Beccue & Vila, 1994). As designers work with 3D worlds, it will be useful to know whether the principles and findings of research related to two-dimensional navigation can be applied and extended. Since virtual worlds represent real worlds, the impact of real world navigational behaviors on interface design must also be studied. A review of the literature related to navigation patterns in human computer interfaces indicates that research on navigation in 3D environments focuses on three areas: (a) navigational awareness, (b) spatial ability, and (c) wayfinding (purposeful, oriented movement during navigation) (Satalich, 1995). Darken and Sibert (1995) found that the organization of elements in a virtual world and the provision of an absolute frame of reference improved navigation performance. In a subsequent study, Darken and Sibert (1996) also reported an improvement in the performance of navigation tasks in virtual worlds that had been created using environmental design principles. Among their observations were that (a) path following (a form of wayfinding) is a natural spatial behavior, (b) the lack of adequate directional cues inhibited wayfinding performance, (c) a structure must be imposed on large complex worlds in order to navigate in them, and (d) a conceptual coordinate system is often imposed on the world in an attempt to structure it. Each of these studies required that the researcher track the users' navigational patterns in a virtual world. Vila, Beccue, and Furness (1997) reported on a tool that provided a template and efficient data collection capabilities for studying the navigational behaviors of users. Additional efforts to improve navigation performance by addressing issues such as the psychology of navigation, the use of navigational aids (e. …