Benefits of merging command selection and direct manipulation

Abstract

Toolglass [Bier et al. 1993] demonstrated a two-handed command selection technique that combined command selection and direct manipulation. While empirical evaluations showed a speed advantage for ToolGlass, they did not examine the relative importance of two possible factors in its improved performance: (1) the use of two hands and (2) the merging of command selection and direct manipulation.We conducted a study comparing the relative benefits of three command selection techniques that merge command selection and direct manipulation: one two-handed technique, Toolglass, and two one-handed techniques, namely, control menus [Pook et al. 2000] and FlowMenu [Guimbretière and Winograd 2000]. Participants performed sequences of operations that required both selecting a color and designating the endpoints of a line. Our results show that control menus and FlowMenu are significantly faster than Toolglass. Further analysis suggests that the merging of command selection and direct manipulation is the most important factor in the performance of all three techniques.