Michael Rietzler

2papers

2 Papers

HCJun 8, 2021
Augmenting Teleportation in Virtual Reality With Discrete Rotation Angles

Dennis Wolf, Michael Rietzler, Laura Bottner et al.

Locomotion is one of the most essential interaction tasks in virtual reality (VR) with teleportation being widely accepted as the state-of-the-art locomotion technique at the time of this writing. A major draw-back of teleportation is the accompanying physical rotation that is necessary to adjust the users' orientation either before or after teleportation. This is a limiting factor for tethered head-mounted displays (HMDs) and static body postures and can induce additional simulator sickness for HMDs with three degrees-of-freedom (DOF) due to missing parallax cues. To avoid physical rotation, previous work proposed discrete rotation at fixed intervals (InPlace) as a controller-based technique with low simulator sickness, yet the impact of varying intervals on spatial disorientation, user presence and performance remains to be explored. An unevaluated technique found in commercial VR games is reorientation during the teleportation process (TeleTurn), which prevents physical rotation but potentially increases interaction time due to its continuous orientation selection. In an exploratory user study, where participants were free to apply both techniques, we evaluated the impact of rotation parameters of either technique on user performance and preference. Our results indicate that discrete InPlace rotation introduced no significant spatial disorientation, while user presence scores were increased. Discrete TeleTurn and teleportation without rotation was ranked higher and achieved a higher presence score than continuous TeleTurn, which is the current state-of-the-art found in VR games. Based on observations, that participants avoided TeleTurn rotation when discrete InPlace rotation was available, we distilled guidelines for designing teleportation without physical rotation.

HCApr 13, 2021
Questionnaires and Qualitative Feedback Methods to Measure User Experience in Mixed Reality

Tobias Drey, Michael Rietzler, Enrico Rukzio

Evaluating the user experience of a software system is an essential final step of every research. Several concepts such as flow, affective state, presences, or immersion exist to measure user experience. Typical measurement techniques analyze physiological data, gameplay data, and questionnaires. Qualitative feedback methods are another approach to collect detailed user insights. In this position paper, we will discuss how we used questionnaires and qualitative feedback methods in previous mixed reality work to measure user experience. We will present several measurement examples, discuss their current limitations, and provide guideline propositions to support comparable mixed reality user experience research in the future.