VRBridge: a Constructivist Approach to Supporting Interaction Design and End-User Authoring in Virtual Reality

For any technology to become widely-used and accepted, it must support end-user authoring and customisation. This means making the technology accessible by enabling understanding of its design issues and reducing its technical barriers. Our interest is in enabling end-users to author dynamic virtual environments (VEs), specifically their interactions: player interactions with objects and the environment; and object interactions with each other and the environment. This thesis describes a method to create tools and design aids which enable end-users to design and implement interactions in a VE and assist them in building the requisite domain knowledge, while reducing the costs of learning a new set of skills. Our design method is based in constructivism, which is a theory that examines the acquisition and use of knowledge. It provides principles for managing complexity in knowledge acquisition: multiplicity of representations and perspectives; simplicity of basic components; encouragement of exploration; support for deep reflection; and providing users with control of their process as much as possible. We derived two main design aids from these principles: multiple, interactive and synchronised domain-specific representations of the design; and multiple forms of non-invasive and user-adaptable scaffolding. The method began with extensive research into representations and scaffolding, followed by investigation of the design strategies of experts, the needs of novices and how best to support them with software, and the requirements of the VR domain. We also conducted a classroom observation of the practices of non-programmers in VR design, to discover their specific problems with effectively conceptualising and communicating interactions in VR. Based on our findings in this research and our constructivist guidelines, we developed VRBridge, an interaction authoring tool. This contained a simple event-action interface for creating interactions using trigger-condition-action triads or Triggersets. We conducted two experimental evaluations during the design of VRBridge, to test the effectiveness of our design aids and the basic tool. The first tested the effectiveness of the Triggersets and additional representations: a Floorplan, a Sequence Diagram and Timelines. We used observation, interviews and task success to evaluate how effectively end-users could analyse and debug interactions created with VRBridge. We found that the Triggersets were effective and usable by novices to analyse an interaction design, and that the representations significantly improved end-user work and experience. The second experiment was large-scale (124 participants) and conducted over two weeks. Participants worked on authoring tasks which embodied typical interactions and complexities in the domain. We used a task exploration metric, questionnaires and computer logging to evaluate aspects of task performance: how effectively end-users could create interactions with VRBridge; how effectively they worked in the domain of VR authoring; how much enjoyment or satisfaction they experienced during the process; and how well they learned over time. This experiment tested the entire system and the effects of the scaffolding and representations. We found that all users were able to complete authoring tasks using VRBridge after very little experience with the system and domain; all users improved and felt more satisfaction over time; users with representations or scaffolding as a design aid completed the task more expertly, explored more effectively, felt more satisfaction and learned better than those without design aids; users with representations explored more effectively and felt more satisfaction than those with scaffolding; and users with both design aids learned better but did not improve in any other way over users with a single design aid. We also gained evidence about how the scaffolding, representations and basic tool were used during the evaluation. The contributions of this thesis are: an effective and efficient theory-based design method; a case study in the use of constructivism to structure a design process and deliver effective tools; a proof-of-concept prototype with which novices can create interactions in VR without traditional programming; evidence about the problems that novices face when designing interactions and dealing with unfamiliar programming concepts; empirical evidence about the relative effectiveness of additional representations and scaffolding as support for designing interactions; guidelines for supporting end-user authoring in general; and guidelines for the design of effective interaction authoring systems in general

Using Visualizations to Support Design and Debugging in Virtual Reality

We present a visualization system that helps designers conceptualise interactions in a virtual environment (VE). We use event-condition-action triads (triggersets) for specifying interactions, and provide multiple visualizations: sequence diagrams, floorplans and timelines. We present a two part study: sequencing VE interactions accurately and debugging mistakes. Subjects were divided into two groups: one received visualizations and triggersets and the other (a control group) received triggersets only. The visualization group described 72.5% of the sequence correctly on average, compared to 56.4% by the non-visualization group. The visualization group also detected more than twice as many errors as the control group. The visualization group worked well with multiple, linked windows to create an understanding of the design. Floorplans were most useful for an overview, timelines for understanding specific sequences and sequence diagrams for sequencing and finding mistakes

Experiences in Designing a User-Oriented Tool for Building and Understanding Interactions in Virtual Environments

Designing a virtual environment and its interactions is a difficult task because of the complexity of specifying non-deterministic relationships between multiple objects. We present a system to help novice designers create interactions in a virtual environment. Our system uses triggersets (event-condition-action triads) for entering interactions. It provides multiple visualizations of the virtual environment and its interactions: a sequence diagram for narrative sequencing, a floorplan for spatial sequencing and a timeline for time sequencing. We conducted an exploratory study with 11 subjects, where some received visualizations and triggersets of a VE and others only received the triggersets. The study had two parts: to assess whether subjects could sequence triggersets accurately and to assess how they managed to debug mistakes in a different set of triggersets. The visualization group described 72.5% of the sequence correct on average, compared to 56.4% by the non-visualization group. For debugging, the visualization group detected more than twice as many errors as the non-visualization group

An Investigation on the Effects of Mediation in a Storytelling Virtual Environment

This paper presents a study that explores the use of mediation in virtual environments (VEs) used for cultural storytelling. A VE was created in which a traditional San story was told. Two forms of mediation were used: visual mediation and audio mediation. Four versions of the VE were implemented, differentiated by the type and amount of mediation included. 77 subjects were tested, each experiencing only one of the versions. Measurements of presence, story involvement and enjoyment of each user were taken. A factorial analysis of variance, with a between-subjects design was used. Audio mediation was found to have an effect on presence(F = 138.8, p < 0.002). Visual mediation was found to increase story involvement (F = 9.49, p < 0.003). Both the interaction between the mediations, and audio mediation increased enjoyment (F = 5.87, p < 0.02 and F = 4.01, p < 0.05 respectively). Therefore, the use of subtle mediation that appears natural in the VE setting was shown to be effective. The effects of audio mediation on presence suggests that it is an important addition to any VE. And, in the context of virtual storytelling, visual mediation is valuable in conveying a narrative more successfully

Designing a VR Interaction Authoring Tool using Constructivist Practices

This paper describes the process of designing an authoring tool for virtual environments, using constructivist principles. The focus of the tool is on helping novice designers without coding experience to conceptualise and visualise the interactions of the virtual environment. According to constructivism, knowledge is constructed by people through interactions with their social and physical environments. Major aspects of this theory are explored, such as multiple representations, reflexivity, exploration, scaffolding and user control. Its practical application to the design of the tool is then described

The Effects of Mediation in a Storytelling Virtual Environment

This paper presents a study that explores the use of mediation in virtual environments (VEs) used for cultural storytelling. A VE was created in which a traditional San story was told. Two forms of mediation were used: visual and audio. Four versions of the VE were implemented, differentiated by the types of mediation included. An experiment was conducted, during which measurements of presence, story involvement and enjoyment were taken. Audio mediation was found to have a positive effect on presence. Visual mediation was found to increase story involvement, which is valuable in conveying a narrative successfully. Both audio mediation and the interaction between the mediations increased enjoyment. Overall, the use of subtle mediations that appear natural in the VE setting was shown to be effective