A comparison of ray pointing techniques for very large displays

Ray pointing techniques such as laser pointing have long been proposed as a natural way to interact with large and distant displays. However we still do not understand the differences between ray pointing alternatives and how they are affected by the large size of modern displays. We present a study where four different variants of ray pointing are tested for horizontal targeting, vertical targeting and tracing tasks in a room-sized display that covers a large part of the user‟s field of view. Our goal was to better understand two factors: control type and parallax under this scenario. The results show that techniques based on rotational control perform better for targeting tasks and techniques with low parallax are best for tracing tasks. This implies that ray pointing techniques must be carefully selected depending on the kind of tasks supported by the system. We also present evidence on how a Fitts‟s law analysis based on angles can explain the differences in completion time of tasks better than the standard analysis based on linear width and distance.