MS Thesis

Virtual Director:

Steering Scientific Visualization with Virtual Camera Choreography

Donna Cox and Bob Patterson using Virtual Director


  • The course of Virtual Director (VD) evolution, from 1993-97, led to the development of a variety of associated systems. Under the generic title "CAVE AllTerrain" (CAT), these library utilities were specifically designed to assist in the implementation of interactive and animated virtual environments for the CAVE.
  • The underlying organization of a CAT program is key to the ability to manipulate cameras and multiple points of view within a given scene description. This ability enables virtual recording and pre-editing of camera motion, and facilitates the design of distributed and networked sessions in a shared environment.
  • An Application Tree structure within the loop supports the specification of nested application modules for building large worlds, supported by default graphical utilities and an extensive 6dof tracker-spline math library. This structure has proven invaluable for managing massive applications and group projects, and implementing elaborate navigational models.
  • The VD system itself forms a partial layer between the graphical user interface of the CAVE and the spatial and time parameters of the application. Control input is funneled primarily through a unix command-line using token strings. A developer is free to disable the VD commands and enhance the environment with customized commands and macros, making the system flexible and extensible.
  • In order to explain how VD works and how it can be used, it is necessary to explain the basic organization of the CAVE loop, how the CAT system manages scenes, and how problems associated with recording and replay of user activity arise and are solved.

  • Contents:

  • Chapter 1
  • Chapter 2
  • Chapter 3
  • Chapter 4
  • Chapter 5

  • Appendices:

  • Appendix A
  • Appendix B
  • Appendix C

  • Bibliography:

  • Gould and Tobochnik.

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  • Ware, C. and Osborne, S.: Exploration and Virtual Camera Control in Virtual Three Dimensional Environments. Proceedings of the Workshop on Interactive 3D Graphics, ACM SIGGRAPH, March 1990, pp. 175-183.

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  • Barsky, B. and Beatty, J: Local Control of Bias and Tension in Beta-Splines. Computer Graphics (proceedings of SIGGRAPH 83), ACM SIGGRAPH, July 1983, pp. 193-218.

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  • Rogers, D. and Adams, J.: Mathematical Elements for Computer Graphics, 2nd Ed., 1990, McGraw-Hill.

  • Loomis, J., Poizner, H., Bellugi, U., Blakemore, A., Hollerbach, J.: Computer Graphic Modeling of American Sign Language. Computer Graphics (proceedings of SIGGRAPH 83), ACM SIGGRAPH, July 1983, pp 105-114.

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  • Kim, M.J., Kim, M.S., Shin, S.: A General Construction Scheme for Unit Quaternion Curves with Simple High Order Derivatives. Computer Graphics (proceedings of SIGGRAPH 95), ACM SIGGRAPH, August 1995, pp. 369-376.

  • Schlag, J.: Using Geometric Constructions to Interpolate Orientation with Quaternions. Graphics GEMS II, Academic Press, 1992, pp. 377-380.

  • Ghazisaedy, M., Adamczyk, D., Sandin, D., Kenyon, R., DeFanti, T.: Ultrasonic Calibration of a Magnetic Tracker in a Virtual Reality Space. Proceedings of the IEEE VRAIS'95, March 1995.

  • DeFanti, T.: Issues in Recording, Editing, and Transmitting Virtual Reality Sessions. (internal communication). May 1994.

  • Proposal: