Gravity Ball - A Virtual Trackball with Ultrasonic Haptic Feedback.

This paper presents a virtual trackball named Gravity Ball. By touching, grabbing, pushing, dragging, swiping, and scrolling the Gravity Ball, a user can conduct multi-mode manipulations on a 3D object via a single interaction medium. Physics-based haptic feedback is provided through ultrasonic-based mid-air haptic device, enabling the user more immersive interaction and more precise manipulation. Potential of the concept is demonstrated through a gun-shooting video game.