Multi-touch RST in 2D and 3D spaces: Studying the impact of directness on user performance

The RST multi-touch technique allows one to simultaneously control Rotations, Scaling, and Translations from multi-touch gestures. We conducted a user study to better understand the impact of directness on user performance for a RST docking task, for both 2D and 3D visualization conditions. This study showed that direct-touch shortens completion times, but indirect interaction improves efficiency and precision, and this is particularly true for 3D visualizations. The study also showed that users' trajectories are comparable for all conditions (2D/3D and direct/indirect). This tends to show that indirect RST control may be valuable for interactive visualization of 3D content. To illustrate this finding, we present a demo application that allows novice users to arrange 3D objects on a 2D virtual plane in an easy and efficient way.