Two uni-manual manipulation techniques with constraints for 3D modeling applications on TabletPCs.

In desktop 3D modeling applications, object manipulation relies on the use of standard transformation widgets. However, these widgets are less efficient on touchscreens due to the low accuracy of touch inputs, and also to the fingertip occlusion issue. In this paper, we propose two unimanual constrained manipulation techniques on TabletPCs. Based on finger identification, our techniques map the index, middle and ring fingers of the dominant hand to the X, Y and Z axes of the coordinate system. After registering the axis-fingers mapping on the screen, users can perform different chording gestures to trigger axis-, plane-constrained or uniform manipulations. We have conducted a user study to examine the learnability and usability of the proposed gestures. The results indicate that these gestures can be memorized quickly after a short training period. Users found some gestures to be easy to use and comfortable while others require additional investigations. These findings permits to give recommendations for designing a unimanual constrained manipulation technique that can be used efficiently in a 3D modeling application on TabletPCs.