Interaction Styles in Development Tools for Virtual Reality Applications

Abstract

Virtual reality display systems reflect an emerging technology that is used to visualize virtual three-dimensional (3D) worlds. This article describes and evaluates tools for developing software applications that are targeted at virtual reality display systems. The evaluation focuses on the relevance of command language or direct manipulation with graphical representation as the fundamental interaction style in such a tool. The foundation of the evaluation is an empirical study of two development processes where two tools representing each of these interaction styles was used to develop the same virtual reality application. The development tool that employed a command language was very flexible and facilitated an even distribution of effort and progress over time, but debugging and identification of errors was very difficult. The tool that employed direct manipulation enabled faster implementation of a first prototype but did not facilitate a shorter implementation process as a whole due to e.g. lack of support for writing code for repetitive operations. The limited advantage of using direct manipulation for developing virtual reality applications is further explored through comparison with a successful direct manipulation tool for developing interactive multimedia applications targeted at traditional desktop computers. From this comparison, a number of central issues for user interface design of highly graphical development tools are pointed out for future design. Methods and guidelines for user interface design embody certain computer technologies. This also applies to interaction styles. Interaction based on a command language was a relevant solution with the character-based display. Direct manipulation emerged from the potentials of the graphical workstation and personal computer. This inherent relation between interface design and computer technology implies that our established guidelines and experiences are challenged when new technologies emerge.