transPAF: Rendering Omnidirectional Impact Feedback with Dynamic Point of Application of Force All Round a Controller

Impact is common feedback on virtual reality (VR) controllers. It applies to different points of application of force (PAFs) and directions in varied scenarios, e.g., using a sword and pickaxe, stabbing and slashing with a sword, or balls flying and hitting a racket in different directions. Therefore, rendering dynamic PAF and force direction is essential. We propose transPAF to render omnidirectional impact feedback with dynamic PAF all round the controller. transPAF consists of a controller, semicircular track, linear track, and impactor, which are all rotatable. The impactor can move to any position in a sphere around the controller and rotate in any direction. Therefore, dynamic PAF and force direction are achieved and independent to each other. We conducted a just-noticeable difference (JND) study to understand users’ distinguishability in position and direction, separately, and a VR study to verify that the feedback with dynamic PAF and force direction enhances VR realism.