Selection in 3D virtual environments can vary wildly depending on the context of the selection. Scene attributes such as object velocity, scene density, and user's cursor velocity can impact the user's ability to accurately select an object. Many 3D selection techniques have been explored, and are usually optimal for a specific set of conditions. As a result, software developers must compromise by choosing a single technique that works well on average, but is lacking in at least one scenario. We present a preliminary study that explores the feasibility of new autoselection algorithms that automatically determines the most appropriate selection technique in real-time, thus leveraging the performance benefits of each technique. We evaluated the techniques across three levels of scene density and three levels of object velocity.

3D object selection is more demanding when, 1) objects densly surround the target object, 2) the target object is significantly occluded, and 3) when the target object is dynamically changing location. Most 3D selection techniques and guidelines were developed and tested on static or mostly sparse environments. In contrast, games tend to incorporate densly packed and dynamic objects as part of their typical interaction. With the increasing popularity of 3D selection in games using hand gestures or motion controllers, our current understanding of 3D selection needs revision. We present a study that compared four different selection techniques under five different scenarios based on varying object density and motion dynamics. We utilized two existing techniques, Raycasting and SQUAD, and developed two variations of them, Zoom and Expand, using iterative design. Our results indicate that while Raycasting and SQUAD both have weaknesses in terms of speed and accuracy in dense and dynamic environments, by making small modifications to them (i.e., flavoring), we can achieve significant performance increases.

We present a Wizard-of-Oz study exploring full body video game interaction. Using the commercial video game Mirror's Edge, players are presented with several different tasks such as running, jumping, and climbing. Following our protocol, participants were given complete freedom in choosing the motions and gestures to compete these tasks. Our experiment results show a mix of natural and constrained gestures adapted to space and field of view restrictions. We present guidelines for future full body interfaces.

3D User Interface (3DUI) design and development requires practitioners (designers and developers) to represent their ideas in representations designed for machine execution rather than natural representations, hampering development of effective 3DUIs. As such, Concept-Oriented Design (COD) was created as a theory of software development for both natural and executable design and development. Instantiated in the toolkit Chasm, Chasm is a natural, tiered, executable User Interface Description Language (UIDL) for 3DUIs resulting in improved understandability, as well as reduced complexity and reuse. Chasm's utility is shown through evaluations by domain experts, case studies of long-term use, and an analysis of spaces .

In our experience, novel ideas for 3D interaction techniques greatly outpace developers' ability to implement them, despite the potential benefit of these ideas. We believe this is due to the inherent implementation complexity of 3D interfaces, without sufficient support from methods and tools. Believing a developer-centric representation could overcome this problem, we investigated developer practices, artifacts and language. This resulted in the theory of concept-oriented design and Chasm, a prototype realization of the theory. The key feature of concept-oriented design is its use of developer-centric representations to create a multi-tiered implementation, ranging from an envisioned behavior expressed in conversational language to low-level code. Evaluation of Chasm by domain experts and its use in multiple case studies has demonstrated that concept-oriented design in Chasm enabled developers to represent an exponential growth in 3D interface complexity with only a linear growth in implementation complexity. Positive comments by developers further support the developer-centric representation.

User-centered design is often performed without regard to individual user differences in aptitude and experience. The methodology of this study is an anthropological and observational approach observing users performing a selection task using common virtual environment raybased techniques and analyzes the interaction through psychology aptitude tests, questionnaires and observation. The results of this study show the approach yields useful information about users even in a simple task. The study indicates correlations between performance and aptitude test and user behavior performed to overcome difficulties in the task.

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

Virtual Reality (VR), Augmented Reality (AR) and other realities along the Mixed Reality(MR) continuum use multi-sensory displays and spatial interaction to enable a number of usefuland novel applications. These virtual worlds are able to train, explore and entertain in addition toaugment the real world with information for our everyday lives. To perform tasks such as traveland other interaction, researchers in these worlds have focused heavily on issues of three-dimensionalinteraction, including interaction techniques, user interface metaphors and inputdevices but always with an outlook centric to their particular position along the MR continuum.This has resulted in interfaces tuned to certain MR instances that are not possible in them allbecause of factors such as the display types, tracking issues or interference and limits from thereal world.This panel brings together diverse researchers across the MR continuum to discuss theirresearch and dissect the similarities and differences of each other's fields. The result is anunderstanding of interfaces across these realities and a merger of developing terminology,techniques and tools for future collaborations.Panel members will give a description of their research followed by a short vision of futureinterface research. Audience questions submitted via index cards are heavily encouraged andexpected to shape the panel discussion and direction.

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.