With seated virtual reality (VR), the use cases based on seating conditions need to be considered while designing the travel and viewing techniques. The most natural method in seated VR, for viewing interactions is the standard 360-degree rotation, for which a swivel chair that spins around the vertical axis is commonly used. However, the VR users will not have the affordances of a swivel chair or the physical space to turn around, all the time. This limits their VR usage based on the availability of certain physical setups. Moreover, for prolonged usage, users might prefer to have convenient viewing interactions by sitting on a couch, not rotating physically all the way around. Our research addresses these scenarios by studying new and existing semi-natural travel and viewing techniques that can be used when full 360-degree rotation is not feasible or is not preferred. Two new techniques, guided head rotation and user-controlled resetting were developed and were compared with existing techniques in three controlled experiments. Standard 360- degree rotation and three joystick-control based viewing techniques (discrete rotation, continuous rotation and continuous rotation with reduced fov) were the existing techniques compared in our experiments. Since the new techniques and some of the existing techniques involve some rotation manipulations that are not natural, they could disorient the users during a virtual experience. So, two VR puzzle games were designed to study the effects of the techniques on spatial awareness of the users. Convenience, simulator sickness, comfort and preferences for home entertainment were the other factors investigated in the experiments. From the experiments, we found out that the results were based on 3D gaming experience of the participants. Participants who played 3D games one or more hours per week had higher tolerance towards the new techniques that had rotational manipulations compared to the participants who did not play any 3D game. Among the joystick rotation techniques, discrete rotation was rated the best by users in terms of simulator sickness. In addition to these experiments, we also present a case study that demonstrates the application of guided head rotation in an experiment that studied natural hand interaction with virtual objects under constrained physical conditions.
