Exploration of Form Factor and Bimanual 3D Manipulation Performance of Rollable In-hand VR Controller

Virtual reality (VR) environments are expected to become future workspaces. An effective bimanual 3D manipulation technique would be essential to support this vision. A ball-shaped tangible input device that can be rolled in a hand is known to be useful for 3D object manipulation because such devices allow users to utilize their finger dexterity. In this study, we further explored the potential of a rollable in-hand controller. First, we evaluated the effects of its form factor on user behavior and performance. Although the size and shape of a rollable controller are expected to influence user behavior and performance, their effects have not been empirically explored in prior works. Next, we evaluated a rollable controller on bimanual 3D assembly tasks. A rollable controller may incur a high mental load as it requires users to use finger dexterity; therefore, the benefit of using such a device in each hand is not obvious. We found that a 5 cm-diameter ball-shaped controller was the most effective among the sizes and forms that we considered, and that a pair of in-hand rollable controllers showed significantly faster completion time than a pair of VR controllers for complex bimanual assembly tasks involving frequent rotations.