A Physical 3D TrackballA Physical 3D TrackballMyung-Soo Kim, Joon-Kyung Seong,Myung-Soo Kim, Joon-Kyung Seong,

Dae-Eun Hyun, Kang-Hoon Lee, Yoo-Jin ChoiDae-Eun Hyun, Kang-Hoon Lee, Yoo-Jin Choi

Seoul National University

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MotivationMotivation

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

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IntroductionIntroduction Conventional Track Balls

• One optical sensor• Only 2 Degrees of Freedom

Our 3D Track Ball• Multiple sensors 3 DOF !

Main ContributionOptimal Locations for Multiple Sensors

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Previous WorkPrevious 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 Tracker36% faster than using Virtual Sphere or Arcball.

• Bullister, 1998• Takahashi and Kuzuya, 1999

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Basic IdeaBasic Idea

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Limitations of Limitations of One Sensor CaseOne Sensor Case

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Optimal Locations of Optimal Locations of Two SensorsTwo Sensors

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Optimal Locations of Optimal Locations of Two SensorsTwo Sensors

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Optimal Locations of Optimal Locations of Three SensorsThree Sensors

sensor. thirda add when we by improvedbeen hasstability Numerical 50%

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A Prototype Hardware DeviceA Prototype Hardware Device Start from two units of the Logitech Marble

Mouse Cut and paste two frames and use two sensors and one ball.

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A Prototype Hardware DeviceA Prototype Hardware Device

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DemonstrationDemonstration

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

faster. performs trackball3Dour ns,orientatio 3D pure matchingFor

44%~30

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Usability Test (6 DOF)Usability Test (6 DOF)

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Usability Test (Rotation)Usability Test (Rotation)

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ConclusionConclusion 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