Many virtual reality (VR) researchers consider exact head registration (HR) and an exact multi-sensory alignment between real world and virtual objects to be a critical factor for effective motor performance in VR. Calibration procedures, however, can be error prone, time consuming and sometimes impractical to perform. To better understand the relationship between head registration and fine motor performance, we conducted a series of reciprocal tapping tasks under four conditions: real world tapping, VR with correct HR, VR with mildly perturbed HR, and VR with highly perturbed HR. As might be expected, VR performance was worse than real world performance. There was no effect of HR perturbation on motor performance in the tapping tasks. We believe that sensorimotor adaptation enabled subjects to perform equally well in the three VR conditions despite the incorrect head registration in two of the conditions. This suggests that exact head registration may not be as critically important as previously thought, and that extensive per-user calibration procedures may not be necessary for some VR tasks.

Complex 3D interaction tasks require the manipulation of a large number of input parameters. Spatial input devices can be constructed such that their structure reflects the task at hand. As such, somatosensory cues that a user receives during device manipulation, as well as a users expectations, are consistent with visual cues from the virtual environment. Intuitively, such a match between the device’s spatial structure and the task at hand would seem to allow for more natural and direct interaction. However, the exact effects on aspects like task performance, intuitiveness, and user comfort, are yet unknown. The goal of this work is to study the effects of input device structure for complex interaction tasks on user performance. Two factors are investigated: the relation between the frame of reference of a user’s actions and the frame of reference

Many virtual reality researchers consider exact head registration and an exact multi-sensory alignment between real world and virtual objects to be a critical factor for ef-fective motor performance in a virtual environment. Calibration procedures for head-mounted displays, however, can be error prone, time consuming and sometimes im-practical to perform. To better understand the relationship between head registration and fine motor performance, we conducted a series of reciprocal tapping tasks under four conditions: real world tapping, virtual reality with correct head registration, virtual reality with mildly perturbed head registration, and virtual reality with highly perturbed head registration. As might be expected, virtual reality performance was worse than real world performance. There was no effect of head registration perturbation on motor performance in the tapping tasks. We believe that sensorimotor adaptation enabled sub-jects to perform equally well in the three virtual reality conditions despite the incorrect head registration in two of the conditions. This suggests that exact head registration may not be as critically important as previously thought, and that extensive per-user calibration procedures may not be necessary for some virtual reality tasks. ii

Abstract — Virtual reality systems often co-locate the display and input (motor) spaces. Many input devices, such as the mouse, use indirect input mappings, and are disjoint from the display space. A study of visual/motor co-location was conducted to determine if there is any benefit to working directly “in ” a virtual environment. Using a fish-tank VR setup, participants performed a 3D object movement task. This required moving an object from the centre of the environment to target regions, using a tracked pen, in both co-located and disjoint display/input conditions. Results were analyzed in the context of Fitts ’ Law, which models rapid aimed movements. Ultimately, no significant differences were found between co-located and disjoint conditions. However, when analyzing object movement in specific directions, the colocated condition was somewhat better than the disjoint one. In particular, movement into the scene was faster when the display and input device were co-located rather than disjoint. Keywords-component; Co-located input and display, virtual hand, human-computer interaction, 3D user interfaces. I.