Dropping the ball: Releasing a virtual grasp

We present a method for improved release of whole-hand virtual grasps. It addresses the problem of objects “sticking” during release after the user's (real) fingers interpenetrate virtual objects due to the lack of physical motion constraints. This problem may be especially distracting for grasp techniques that introduce mismatches between tracked and visual hand configurations to prevent visual interpenetration. Our method includes heuristic analysis of finger motion and a transient incremental motion metaphor to manage a virtual hand during grasp release. We incorporate the method into a spring model for whole-hand virtual grasping. We show that the new spring model improves speed and accuracy for a targeted ball-drop task, and users report a subjective preference for the new behavior. In contrast to a standard spring-based grasping method, measured release quality does not depend notably on object size.