A Physical 3D Trackball

1
A Physical 3D Trackball

• Myung-Soo Kim, Joon-Kyung Seong,
• Dae-Eun Hyun, Kang-Hoon Lee, Yoo-Jin Choi
• Seoul National University

2
Motivation
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
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
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
Basic Idea
7
Limitations of One Sensor Case
8
Optimal Locations of Two Sensors
9
Optimal Locations of Two Sensors
10
Optimal Locations of Three Sensors
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
A Prototype Hardware Device
13
Demonstration
14
Usability Test

• 3D Trackball vs. the Magellan/SPACE MOUSE

15
Usability Test (6 DOF)
16
Usability Test (Rotation)
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.
• 3044 faster than Magellan/SPACE MOUSE