A challenge in presenting augmenting information in outdoor augmented reality (AR) settings lies in the broad range of uncontrollable environmental conditions that may be present, specifically large-scale fluctuations in natural lighting and wide variations in likely backgrounds or objects in the scene. In this paper, we present a user-based study which examined the effects of outdoor background textures, changing outdoor illuminance values, and text drawing styles on user performance of a text identification task with an optical, see-through augmented reality system. We report significant effects for all of these variables, and discuss design guidelines and ideas for future work.

Three-dimensional objects in many applications domains, such as architecture and construction, can be extremely complex and can consist of a large number of components. However, many of these complex objects also contain a great deal of repetition. Therefore, cloning techniques, which generate multiple spatially distributed copies of an object to form a repeated pattern, can be used to model these objects more efficiently. Such techniques are important and useful in desktop three-dimensional modeling systems, but we are not aware of any cloning techniques designed for immersive virtual environments (VEs). In this paper, we present an initial effort toward the design and development of such interfaces. We define the design space of the cloning task, and present five novel VE interfaces for cloning, then articulate the design rationale. We have also performed a usability study intended to elicit subjective responses with regard to affordances, feedback, attention, perceived usefulness, ease of use, and ease of learning in these interfaces. The study resulted in four major conclusions. First, slider widgets are better suited for discrete than for continuous numeric input. Second, the attentional requirements of the interface increase with increased degrees-of-freedom associated with widgets. Third, users prefer constrained widget movement, although more degrees-of-freedom allow more efficient parameter setting. Finally, appropriate feedback can reduce the cognitive load. The lessons we learned will influence our continuing design of cloning techniques, and these techniques will ultimately be applied to VE applications for design, construction, and prototyping

Immersive virtual environments (VEs) offer interactive, real-time visualization capabilities for engineers, architects, and scientists. This paper presents Virtual-SAP, an immersive VE application allowing users to assess building structures and their response to various environmental conditions through an interactive design-build-test-redesign cycle. Virtual-SAP has three distinct user interfaces that support its use with a high-end, multi-tracker VE system, with a low-cost portable VE system, or on the desktop. Two of these interfaces have been proven highly usable in user testing, and the third will be tested soon. Virtual-SAP is being used for both research and education.