Interaction Effects of Compound Interaction Tech-
niques in Parallel . . . . . . . . . . . . . . . . 36
3.4 Formal Description of Interaction Techniques with BodyScape 39
3.5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
3.6 Contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
4 The Effect of Support on Input Motor Assemblies 43
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
4.2 Motivation for Bimanual Interaction with the Support Hand . 44
4.2.1 Related Work . . . . . . . . . . . . . . . . . . . . . . . . 45
4.3 Preliminary Study: How do People Hold Tablets? . . . . . . . 46
4.3.1 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
4.3.2 Design Implications . . . . . . . . . . . . . . . . . . . . 48
4.4 The BiPad Prototype . . . . . . . . . . . . . . . . . . . . . . . . 49
4.4.1 BiPad Toolkit and Applications . . . . . . . . . . . . . . 49
4.4.2 BiPad Interaction Techniques for the Non-Dominant
Support Hand . . . . . . . . . . . . . . . . . . . . . . . . 50
4.4.3 Sample BiPad Applications . . . . . . . . . . . . . . . . 51
4.5 Classifying Tablet Holds . . . . . . . . . . . . . . . . . . . . . . 52
4.5.1 Kinematic Chain Theory: Modeling Bimanual Action . 53
4.5.2 BiTouch Design Space: Framing, Support, Interaction . 54
4.6 Evaluating Interaction with the Support Hand . . . . . . . . . 57
4.7 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60