Selection in Mixed Reality: Designing a Two-Phase Technique To Reduce Fatigue

Mid-air pointing is widely used for 3D selection in Mixed Reality but leads to arm fatigue. In a first exploratory experiment we study a two-phase design and compare modalities for each phase: mid-air gestures, eye-gaze and microgestures. Results suggest that eye-gaze and microgestures are good candidates to reduce fatigue and improve interaction speed. We therefore propose two 3D selection techniques: Look&MidAir and Look&Micro. Both techniques include a first phase during which users control a cone directed along their eye-gaze. Using the flexion of their non-dominant hand index finger, users pre-select the objects intersecting this cone. If several objects are pre-selected, a disambiguation phase is performed using direct mid-air touch for Look&MidAir or thumb to finger microgestures for Look&Micro. In a second study, we compare both techniques to the standard raycasting technique. Results show that Look&MidAir and Look&Micro perform similarly. However they are 55% faster, perceived easier to use and are less tiring than the baseline. We discuss how the two techniques could be combined for greater flexibility and for object manipulation after selection.