1. A Physical 3D Trackball A Physical 3D Trackball Myung-Soo Kim, Joon-Kyung Seong, Dae-Eun Hyun, Kang-Hoon Lee, Yoo-Jin Choi Seoul National University

2. 2 Motivation

3. 3 Outline  Introduction  Related Work  Basic Idea  Limitations of One Sensor Case  Optimal Locations of Multiple Sensors  A Prototype Hardware Device  Usability Tests  Conclusion

4. 4 Introduction  Conventional Track Balls One optical sensor Only 2 Degrees of Freedom  Our 3D Track Ball Multiple sensors  3 DOF ! Main Contribution Optimal Locations for Multiple Sensors

5. 5 Previous Work  Virtual 3D Trackball Virtual Sphere (Chen et al., 1988) Arcball (Shoemake, 1992)  Physical 3D input devices Hinckley et al., 1997  Compare 3D Ball and Tracker  36% faster than using Virtual Sphere or Arcball. Bullister, 1998 Takahashi and Kuzuya, 1999

6. 6 Basic Idea

7. 7 Limitations of One Sensor Case

8. 8 Optimal Locations of Two Sensors

9. 9

10. 10 Optimal Locations of Three Sensors

11. 11 A Prototype Hardware Device  Start from two units of the Logitech Marble Mouse  Cut and paste two frames and use two sensors and one ball.

12. 12 A Prototype Hardware Device

13. 13 Demonstration

14. 14 Usability Test  3D Trackball vs. the Magellan/SPACE MOUSE

15. 15 Usability Test (6 DOF)

16. 16 Usability Test (Rotation)

17. 17 Conclusion  Simple method for constructing a physical 3D trackball Tangential velocities at multiple points on a sphere  angular velocity of the rotating ball 2 sensors  3 sensors : 50% improvement for numerical stability.  A prototype hardware has been constructed from two conventional trackballs Stable and efficient for real-time performance. 30~44% faster than Magellan/SPACE MOUSE