Evaluation of Combinatorial Visual Feedback for Virtual Grasping with Bare Hands

Due to the lack of haptic feedback and depth cues in virtual environments, visual feedback is usually used as a substitute to guide users during virtual grasping with bare hands. Prior studies have designed and evaluated visual cues for a portion of the interaction process of virtual grasping, such as the object proximity phase, the object contact phase, and the object grasping phase. However, a visual feedback strategy for the entire process of virtual grasping has not been proposed. In this paper, we proposed four combinations of visual feedback from three types of single visual feedback including proximity feedback, contact feedback, and grasp confirmation feedback. We presented a controlled usability evaluation of combinatorial visual feedback and single visual feedback in virtual object-grasping tasks using bare hands. The results show that proximity + grasp confirmation feedback and proximity + contact + grasp confirmation feedback are superior in task performance and user satisfaction. To rationalize the trade-off between cost-effectiveness and high performance, we further recommend proximity + grasp confirmation feedback as the visual feedback strategy for virtual grasping.