Orientation on Tabletop Displays

Tabletop computer displays suffer from an orientation problem. Solutions based on competing approaches have been implemented, but there remain unanswered questions about the ideal solution. Within a context of interacting with documents on tabletop displays, requirements for orientation control were found by examining literature on how people use paper documents and what manipulations they perform. It was determined that control must provide quick, either-handed, low-attention manipulation of individual objects on the display. An evaluation of existing interaction techniques for rotation was performed in light of these criteria. The trade-off between two desirable characteristics, integral translation and rotation, and direct input, was examined. An evaluation of mouse-based techniques confirmed that integral input has the potential to be faster than the established sequential-manipulation techniques due to the time saved by overlapping manipulation of different degrees of freedom. For a single task combining translation and rotation the separable technique took twice as long compared to two separate tasks of the same translation or rotation, whereas the integral techniques took less time for the combined action than the two separate actions. However, the integral mouse-based techniques were too slow in their actual manipulation, with the scroll wheel taking four times as long to rotate than the separable technique, and the new drag technique not being used in an integral manner. It was concluded that the current generally available technology such as the mouse and single-point touch-sensitive overlays are inadequate. Acceptable tabletop orientation control will be dependent on the maturation of newer technologies based on tangible interfaces or possibly multi-finger input. Until then, interaction techniques for manipulating documents on tabletop displays should be chosen according to their ability to concurrently control position and orientation, such as three degree-of-freedom input devices on digitizing tablets.