MagicalHands: Mid-Air Hand Gestures for Animating in VR

We seek to understand the preferred hand gestures for canonical animation authoring tasks in virtual reality (VR) environments. We first perform a gesture elicitation study for animation authoring to understand user preferences for a spatio-temporal bare-handed interaction system in VR. Specifically, we focus on the creation and editing of dynamic, physical phenomena (e.g., particle systems, deformation, coupling), where the mapping from gesture to animation is ambiguous and indirect. We present commonly observed mid-air gestures from the study, eliciting a set of rich interaction techniques---from direct manipulation to abstract demonstrations. To this end, we extend existing gesture taxonomies to the rich spatiotemporal interaction space needed by animators for authoring in both space and time. We distill our findings into a set of design guidelines for the construction of natural user interfaces for VR-based animation systems. Finally, based on our guidelines, we develop a proof-of-concept gestural animation system in VR. Our results, as well as feedback from user evaluation, suggest that the expressive qualities of hand gestures effectively allow users to animate in VR.