In virtual reality, hybrid virtual environment (HVE) systems provide the immersed user with multiple interactive representations of the virtual world, and can be effectively used for 3D interaction tasks with highly diverse requirements. We present a new HVE metaphor called Object Impersonation that allows the user to not only manipulate a virtual object from outside, but also become the object, and maneuver from inside. This approach blurs the line between travel and object manipulation, leading to efficient cross-task interaction in various task scenarios. Using a tablet- and HMD-based HVE system, two different designs of Object Impersonation were implemented, and compared to a traditional, non-hybrid 3D interface for three different object manipulation tasks. Results indicate improved task performance and enhanced user experience with the added orientation control from the object's point of view. However, they also revealed higher cognitive overhead to attend to both interaction contexts, especially without sufficient reference cues in the virtual environment.

In this paper we revisit the design of leaning-based travel interfaces and propose a design space to categorize existing implementations. Within the design space, frontal and sidewise stances when using a flying surfboard interface were compared through a user study. The interfaces were adapted and improved from our previous designs using a body-mounted, multi-touch touchpad. Two different experiments were designed and conducted that focus on user performance and virtual world cognition, respectively. The results suggest better user performance and user experience when using the frontal stance, although no better spatial orientation or virtual world cognition was identified. Further, user interviews revealed that despite the realistic simulation of skateboarding/snowboarding, the sidewise stance suffers from poor usability due to inefficient and inaccurate turning control and confusion between the viewing and movement directions. Based on these results, several guidelines are proposed to aid the design of leaning-based travel interfaces for immersive virtual reality applications.