Turn-It-Up: Rendering Resistance for Knobs in Virtual Reality through Undetectable Pseudo-Haptics

Rendering haptic feedback for interactions with virtual objects is an essential part of effective virtual reality experiences. In this work, we explore providing haptic feedback for rotational manipulations, e.g., through knobs. We propose the use of a Pseudo-Haptic technique alongside a physical proxy knob to simulate various physical resistances. In a psychophysical experiment with 20 participants, we found that designers can introduce unnoticeable offsets between real and virtual rotations of the knob, and we report the corresponding detection thresholds. Based on these, we present the Pseudo-Haptic Resistance technique to convey physical resistance while applying only unnoticeable pseudo-haptic manipulation. Additionally, we provide a first model of how C/D gains correspond to physical resistance perceived during object rotation, and outline how our results can be translated to other rotational manipulations. Finally, we present two example use cases that demonstrate the versatility and power of our approach.