Investigating User Requirements and Usability of Immersive Three-dimensional Sketching for Early Conceptual Design - Results from Expert Discussions and User Studies

Abstract

As immersive 3-d user interfaces reach broader acceptance, their use as sketching media is attracting both commercial and academic research. So far little is known about user requirements and cognitive aspects of immersive 3-d sketching. Also its integration into the workflow of virtual product development is far from being solved. In this paper we present results from two focus group expert discussions and a comparative user study on immersive 3-d sketching which we conducted among professional furniture designers. The results of the focus groups show a strong interest in using the three-dimensional space as a medium for conceptual design. Users expect it to provide new means for the sketching process, namely spatiality, one-to-one proportions, associations, and formability. Eight groups of functions required for 3-d sketching were generated during the discussions. The results from the user study show that both the sketching process and the resulting sketches differ in the 2-d and 3-d condition, namely in terms of the perceived fluency of sketch creation, of the perceived appropriateness for the task, of the perceived stimulation by the medium, movement speed, sketch sizes, details, functional aspects, and usage time. We argue that both 2-d and 3-d sketching are relevant for early conceptual design. As progress towards 3-d sketching, new tangible interactive tools are needed which account for the user's perceptual and cognitive abilities.