Touching the Sphere: Leveraging Joint-Centered Kinespheres for Spatial User Interaction

Abstract

Designing spatial user interfaces for virtual reality (VR) applications that are intuitive, comfortable and easy to use while at the same time providing high task performance is a challenging task. This challenge is even harder to solve since perception and action in immersive virtual environments differ significantly from the real world, causing natural user interfaces to elicit a dissociation of perceptual and motor space as well as levels of discomfort and fatigue unknown in the real world. In this paper, we present and evaluate the novel method to leverage joint-centered kinespheres for interactive spatial applications. We introduce kinespheres within arm's reach that envelope the reachable space for each joint such as shoulder, elbow or wrist, thus defining 3D interactive volumes with the boundaries given by 2D manifolds. We present a Fitts' Law experiment in which we evaluated the spatial touch performance on the inside and on the boundary of the main joint-centered kinespheres. Moreover, we present a confirmatory experiment in which we compared joint-centered interaction with traditional spatial head-centered menus. Finally, we discuss the advantages and limitations of placing interactive graphical elements relative to joint positions and, in particular, on the boundaries of kinespheres.