UCT CS Research Document Archive

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

Winterbottom, Cara (2010) VRBridge: a Constructivist Approach to Supporting Interaction Design and End-User Authoring in Virtual Reality. PhD, Department of Computer Science, University of Cape Town.

Full text available as:
PDF - Requires Adobe Acrobat Reader or other PDF viewer.


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.

EPrint Type:Electronic Thesis or Dissertation
Keywords:constructivism, virtual reality, system design
Subjects:D Software: D.0 GENERAL
J Computer Applications: J.0 GENERAL
ID Code:607
Deposited By:Winterbottom, Cara
Deposited On:08 June 2010