The effect of 3D widget representation and simulated surface constraints on interaction in virtual environments

The paper reports empirical results from two studies of effective user interaction in immersive virtual environments. The use of 2D interaction techniques in 3D environments has received increased attention recently. We introduce two new concepts to the previous techniques: the use of 3D widget representations; and the imposition of simulated surface constraints. The studies were identical in terms of treatments, but differed in the tasks performed by subjects. In both studies, we compared the use of two-dimensional (2D) versus three-dimensional (3D) interface widget representations, as well as the effect of imposing simulated surface constraints on precise manipulation tasks. The first study entailed a drag-and-drop task, while the second study looked at a slider-bar task. We empirically show that using 3D widget representations can have mixed results on user performance. Furthermore, we show that simulated surface constraints can improve user performance on typical interaction tasks in the absence of a physical manipulation surface. Finally, based on these results, we make some recommendations to aid interface designers in constructing effective interfaces for virtual environments.