Cueing Sequential 6DoF Rigid-Body Transformations in Augmented Reality

Augmented reality (AR) has been used to guide users in multi-step tasks, providing information about the current step (cueing) or future steps (precueing). However, existing work exploring cueing and precueing a series of rigid-body transformations requiring rotation has only examined one-degree-of-freedom (DoF) rotations alone or in conjunction with 3DoF translations. In contrast, we address sequential tasks involving 3DoF rotations and 3DoF translations. We built a testbed to compare two types of visualizations for cueing and precueing steps. In each step, a user picks up an object, rotates it in 3D while translating it in 3D, and deposits it in a target 6DoF pose. Action-based visualizations show the actions needed to carry out a step and goal-based visualizations show the desired end state of a step. We conducted a user study to evaluate these visualizations and the efficacy of precueing. Participants performed better with goal-based visualizations than with action-based visualizations, and most effectively with goal-based visualizations aligned with the Euler axis. However, only a few of our participants benefited from precues, most likely because of the cognitive load of 3D rotations.