Exploring Multi-touch Contact Size for Z-Axis Movement in 3D Environments

In this paper we examine two methods for using relative contact size as an interaction technique for 3D environments on multi-touch capacitive touch screens. We refer to interpreting relative contact size changes as “pressure” simulation. We conducted a 2 x 2 withinsubjects experimental design using two methods for pressure estimation (calibrated and comparative) and two different 3D tasks (bidirectional and unidirectional). Calibrated pressure estimation was based upon a calibration session, whereas comparative pressure estimation was based upon the contact size of each initial touch. The bidirectional task was guiding a ball through a hoop, while the unidirectional task involved using pressure to rotate a stove knob. Results indicate that the preferred and best performing pressure estimation technique was dependent on the 3D task. For the bidirectional task, calibrated pressure performed significantly better, while the comparative method performed better for the unidirectional task. We discuss the implications and future research directions based on our findings.