Keep Your Eyes on the Target: Enhancing Immersion and Usability by Designing Natural Object Throwing with Gaze-based Targeting

While controllers can support many generic 3D interactions in virtual reality (VR), it alone may fall short of eliciting the core experience for certain actions. One such task is the "object throwing'', ubiquitous in many sports contents, involving intricately timed actions of aiming, arm swinging, and object releasing. With the increasing availability of eye tracking, we propose to combine gaze-based targeting with the controller swing gesture to model the object throw. The target is aimed/locked by gaze, and the throw is enacted by the controller swing/button press with the object let-gone by the button release. We compare and evaluate the proposed interface against the conventional controller-only based interaction through two typical baseball tasks - Pitcher and Outfielder. The findings indicated that the task accuracy was similar, but the gaze-based targeting allowed for faster completion. More importantly, the gaze-based method showed significantly higher usability and richer VR experience.