Implementing flexible rules of interaction for object manipulation in cluttered virtual environments

Object manipulation in cluttered virtual environments (VEs) brings additional challenges to the design of interaction algorithms, when compared with open virtual spaces. As the complexity of the algorithms increases so does the flexibility with which users can interact, but this is at the expense of much greater difficulties in implementation for developers. Three rules that increase the realism and flexibility of interaction are outlined: collision response, order of control, and physical compatibility. The implementation of each is described, highlighting the substantial increase in algorithm complexity that arises. Data are reported from an experiment in which participants manipulated a bulky virtual object through parts of a virtual building (the piano movers’ problem). These data illustrate the benefits to users that accrue from implementing flexible rules of interaction

Characterizing Navigational Tools in a Virtual Search Task

The goal of this thesis is to characterize and empirically compare navigational tools in the context of a virtual inspection task. The framework considers both directional-cue navigational tools (e.g., GPS navigation arrows) and trail navigational tools (e.g.,footprints) in comparison to a control condition. Characterizing the tools allows for documented relationships between specific navigational tool-performance combinations. It is intended that by characterizing and comparing the tools a more advantageous use of navigational tools will emerge to increase the benefit provided to both the users and implementers of virtual environments. The focus of the metrics in the paper were distance traveled, speed of travel, and average target acquisition time (via SATO analysis) due to their presence in the literature. Targeted recommendations can be made based on the level of participant\u27s experience with virtual environments, or a general recommendation can be made based upon desired performance metric

Exploring individual user differences in the 2D/3D interaction with medical image data

User-centered design is often performed without regard to individual user differences. In this paper, we report results of an empirical study aimed to evaluate whether computer experience and demographic user characteristics would have an effect on the way people interact with the visualized medical data in a 3D virtual environment using 2D and 3D input devices. We analyzed the interaction through performance data, questionnaires and observations. The results suggest that differences in gender, age and game experience have an effect on people’s behavior and task performance, as well as on subjective\ud user preferences

Movement around real and virtual cluttered environments

Two experiments investigated participants’ ability to search for targets in a cluttered small-scale space. The first experiment was conducted in the real world with two field of view conditions (full vs. restricted), and participants found the task trivial to perform in both. The second experiment used the same search task but was conducted in a desktop virtual environment (VE), and investigated two movement interfaces and two visual scene conditions. Participants restricted to forward only movement performed the search task quicker and more efficiently (visiting fewer targets) than those who used an interface that allowed more flexible movement (forward, backward, left, right, and diagonal). Also, participants using a high fidelity visual scene performed the task significantly quicker and more efficiently than those who used a low fidelity scene. The performance differences between all the conditions decreased with practice, but the performance of the best VE group approached that of the real-world participants. These results indicate the importance of using high fidelity scenes in VEs, and suggest that the use of a simple control system is sufficient for maintaining ones spatial orientation during searching

Cultural Learning in Virtual Environments

This paper is a survey of evaluation mechanisms that may be specifically suitable for virtual heritage environments and also to some extent for social learning environments. It suggests in particular new terms and criteria to assess the contextual appropriateness of various evaluation methods. From two working examples it also reviews issues and lessons learnt from current ongoing research. The first case study of Palenque in Mexico involved five types of evaluation specifically chosen to assess cultural awareness and understanding gained from different forms of interaction in a virtual heritage environment. The second case study, "Virtual Babel", will attempt to use some of these evaluation methods to track cultural learning between students in Japan and in Australia using an online virtual world

Symmetric and asymmetric action integration during cooperative object manipulation in virtual environments

Cooperation between multiple users in a virtual environment (VE) can take place at one of three levels. These are defined as where users can perceive each other (Level 1), individually change the scene (Level 2), or simultaneously act on and manipulate the same object (Level 3). Despite representing the highest level of cooperation, multi-user object manipulation has rarely been studied. This paper describes a behavioral experiment in which the piano movers' problem (maneuvering a large object through a restricted space) was used to investigate object manipulation by pairs of participants in a VE. Participants' interactions with the object were integrated together either symmetrically or asymmetrically. The former only allowed the common component of participants' actions to take place, but the latter used the mean. Symmetric action integration was superior for sections of the task when both participants had to perform similar actions, but if participants had to move in different ways (e.g., one maneuvering themselves through a narrow opening while the other traveled down a wide corridor) then asymmetric integration was superior. With both forms of integration, the extent to which participants coordinated their actions was poor and this led to a substantial cooperation overhead (the reduction in performance caused by having to cooperate with another person)

Movement around real and virtual cluttered environments

Two experiments investigated participants’ ability to search for targets in a cluttered small-scale space. The first experiment was conducted in the real world with two field of view conditions (full vs. restricted), and participants found the task trivial to perform in both. The second experiment used the same search task but was conducted in a desktop virtual environment (VE), and investigated two movement interfaces and two visual scene conditions. Participants restricted to forward only movement performed the search task quicker and more efficiently (visiting fewer targets) than those who used an interface that allowed more flexible movement (forward, backward, left, right, and diagonal). Also, participants using a high fidelity visual scene performed the task significantly quicker and more efficiently than those who used a low fidelity scene. The performance differences between all the conditions decreased with practice, but the performance of the best VE group approached that of the real-world participants. These results indicate the importance of using high fidelity scenes in VEs, and suggest that the use of a simple control system is sufficient for maintaining ones spatial orientation during searching

EVALUATION FRAMEWORK FOR 3D COLLABORATIVE VIRTUAL ENVIRONMENTS (THE CORE)

As a consequence of the increasing interest in Collaborative Virtual Environments (CVEs) and the complex nature of such systems, the need for a thorough evaluation framework has become necessary. The current evaluation frameworks suffer from limitations in assessment because they are either confined to evaluation of a specific type of CVE or they focus on a restricted aspect of CVE. This paper presents a framework for THorough Evaluation of COllaborative viRtual Environment (THE CORE). The proposed framework is structured in a four-layered architecture to assure evaluation of the multi-faceted aspects comprising a CVE. The layers evaluate the application usability, tool usability, companion interaction and collaboration outcome. Within each layer, key evaluation tools and factors are provided. In addition, the framework is designed to be generic to be suitable for different types of CVEs. In order to validate the proposed framework, a case study was conducted involving development and evaluation of a 3D CVE. The case study found the four-layered framework to be useful for evaluating both the technical and behavioural aspects of the 3D CVE. As future work, the generality of the framework will be further tested on different types of CVE, potentially leading to modifications and extensions

Three levels of metric for evaluating wayfinding

Three levels of virtual environment (VE) metric are proposed, based on: (1) users’ task performance (time taken, distance traveled and number of errors made), (2) physical behavior (locomotion, looking around, and time and error classification), and (3) decision making (i.e., cognitive) rationale (think aloud, interview and questionnaire). Examples of the use of these metrics are drawn from a detailed review of research into VE wayfinding. A case study from research into the fidelity that is required for efficient VE wayfinding is presented, showing the unsuitability in some circumstances of common metrics of task performance such as time and distance, and the benefits to be gained by making fine-grained analyses of users’ behavior. Taken as a whole, the article highlights the range of techniques that have been successfully used to evaluate wayfinding and explains in detail how some of these techniques may be applied