Consequence of Two-handed Manipulation on Speed, Precision and Perception on Spatial Input Task in 3D Modelling Applications

We developed a free form deformation application for an immersive environment in which users can interact freely using data gloves. To ensure better comfort and performances, we added the possibility of bi-manual interaction in our environment. To investigate the actual gain obtained by this interaction technique we designed an experimental protocol based on spatial input tasks. In our experiment, we asked our subjects to use only the dominant hand to achieve the different tasks or, on the contrary, to use both hands. Comparison of users' performances - i-e, time and precision - shows that, without proper training, executing a task using two hands can be more time consuming than using one hand. In fact, the degree of symmetry of the tasks performed with each hand seem to have a significant impact on whether or not users take advantage of bi-manual possibilities. Our results also show that bi-manual interaction can introduce proprioceptive cues that can be of help to achieve more precision in the placement or selection only when proper visual information are missing. In this study, we also wanted to investigate if bi-manual interaction can help users in their perception of the task. Even if there aren't statistically significant, our results shows that using symmetric bi-manual interaction, proprioception cues can improve user's perception.