Effects of Switchable DOF for Mid-Air Manipulation in Immersive Virtual Environments

In the context of mid-air manipulation, this paper presents the effects of allowing the user to dynamically switch between 1DOF, 2DOF, and 3DOF operations. Such "manipulation with switchable DOF" has been widely used in commercial graphics packages and is increasingly being adopted for virtual reality editing, where the 3D scene is constructed through mid-air interaction in immersive virtual environments. However, its effectiveness and advantages/disadvantages have not been investigated. This paper compares "manipulation with switchable DOF" with "manipulations with DOF separation," which allows only 1DOF operations, and "manipulation without DOF separation," which provides 3DOF operations. Using translation, rotation, and scaling, three methods were evaluated in terms of completion time and precision. The experiment results showed that "manipulation with switchable DOF" outperformed "manipulation with DOF separation" in terms of completion time whereas three methods were comparable in terms of precision. "Manipulation with switchable DOF" was further analyzed, and the results showed that the more 3DOF operations led to the shorter completion time and the more 1DOF operations led to the higher precision.