Annotating animated AR objects for co-located learning

Annotations in learning environments are used to extend information about objects and to enhance the teacher-student interactions. In augmented reality (AR) environments, learners annotate 3D virtual objects in order to draw attention to a particular area of concern. However, annotations become problematic when 3D objects move in space or their content is animated. Traditional annotation techniques (e.g., labels and sketches) have limitations when deployed with moving objects. In response, we develop an AR prototype system to determine the types of annotations that would enhance co-located learning with animated virtual objects. In our participant study, we observed physiotherapy teachers and students using the system to analyze and annotate human movement (prerecorded and live). We investigated human interaction with virtual objects and describe types of AR annotations. We find that classic annotations are not common with animated objects. Instead, participants construct imaginary cues (virtual lines and anchor points) that are then augmented with visual annotations.