VR-Grasp: A Human Grasp Taxonomy for Virtual Reality

This article presents a comprehensive Virtual Reality (VR) grasping taxonomy, which represents the common grasping patterns employed by users in VR, and is directly comparable to real object grasping taxonomies. With grasping being one of the primary interfaces we have with the physical world, seminal work has sought to explore our explicit grasping actions with real objects with the aim to define structured reasoning in the form of taxonomies. However, limited work has replicated this approach, for immersive technology (i.e., VR) and to address this, we present the first complete taxonomy of grasping interaction for VR, which builds on the body of work from real object grasping alongside recent approaches which have been applied into VR. We present a formal elicitation study, wherein a Wizard of Oz (WoZ) methodology is applied with users (N = 50) tasked to grasp and translate virtual twins of real objects. We present results from the analysis of 4800 grasps into a formal structured taxonomy which details the frequency of all potential real grasps and draws comparisons to the body of prior work in both real grasping and VR grasping studies. Results highlight the reduced number of grasp types used in VR (27), and the differences in commonality, frequency, and grasping approach between real grasping and VR grasping taxonomies. Focus is especially given to the nuances of the grasp, and via an in-depth evaluation of object properties, namely shape and size, we illustrate the common trends in VR grasping. Results from this work are also combined with VR grasping findings from prior published work, leading to the presentation of the most common grasps (5) for VR and recommendations for future analysis and use in intuitive and natural VR systems.