niklas elmqvist | phd thesis

3D Occlusion Management and Causality Visualization

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PhD dissertation.

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This is the official website for Niklas Elmqvist's Ph.D. dissertation, titled 3D Occlusion Management and Causality Visualization. Below is some introductory material for the thesis, followed by more in-depth information on the research (including the thesis itself!). In an attempt to practice what I preach, I have also included a visualization of the concepts found in this thesis. I think it gives a pretty good indication of the contents.

  • Summary (including popular description) of the thesis (both Swedish and English)
  • Photograph of author (small version)
  • Photograph of author (big version)

Use the local links below to navigate on this webpage.

[ thesis | defense | popular | image gallery | concepts | papers ]

current version

A current version of the PhD thesis will always be available here:

  • Thesis (2006-11-20) [PDF] (14 MB)

The PhD dissertation will be defended in public at 10.15 on December 19th, 2006 in Lecture room EC, ED&IT-building, Chalmers University of Technology, Gothenburg, Sweden. The defense will be held in English.

Faculty opponent is Associate Professor Doug A. Bowman, Department of Computer Science, Virginia Polytechnic Institute & State University. Grading committee members are Stephan Diehl, Lars Hallnäs, Diane Sonnenwald, and Morten Fjeld.

Preliminary schedule of the defense below:

  • 10.15 - introduction and general presentation by the opponent.
  • 10.40 - detailed presentation by the candidate.
  • 11.00 - break (5-10 minutes)
  • 11.10 - ... - opponent questions, grading committee questions, questions from the audience

Some in-depth information, including the public PhD defense announcement, can be found below:

  • Maps of Chalmers (directions on how to find Chalmers can be found here)
  • The opponent is giving a research talk on 3D interaction for large displays on Monday the 18th of December
popular description

There is a popular description of the thesis available below in both English as well as Swedish. This description gives a general introduction to the contents of the thesis in a way suitable to the public. Please do not hesitate to contact me if you have any additional questions.

  • Popular summary of the thesis (both Swedish and English)
  • Summary (including popular description) of the thesis (both Swedish and English)
image gallery

Here is a collection of images related to the thesis.

BalloonProbe (cover image).
Wedge-shaped BalloonProbe.
Sphere-shaped BalloonProbe.
3D Jeep.
3D Jeep with X-Ray.
Complex 3D landscape.
3D forest.
3D tank shown with X-Ray.
Abstract information landscape.
Causality visualization.
Scientific authors.
Keywords concept map.


Below is an illustration of the 150 most common concepts in the thesis, scaled according to frequency:

3d abstract access active algorithm animation application approach article balloonprobe basic both camera case causal causality citation citewiz color completion complex computer control correctness cues current data database dense density depth design designed diagrams difference different discovery distance dynamic effect efficiency efficient environment error evaluation example execution experimenter field find following form general given gives good growing hasse high however human i.e implementation important individual influence information interaction interactive large management map mean method minutes mode model navigation neutral new normal number object occluded occlusion order overview paper parallel pattern perception performance performed perspective phase point polygons possible present problem process projection purpose questionnaire questions related relation rendering results s.d scenario search seconds set show significant simple size solving space sparse spatial squares standard study subject system target task taxonomy technique test time times tour transparency use user using various way versus view viewpoint virtual visible visual visualization work world

included papers

The thesis is based on the following conference papers, journal papers, and technical reports:

  1. Elmqvist, N., Tsigas, P. On Navigation Guidance for Exploration of 3D Environments. Technical report CS:2006-19, Chalmers University of Technology, Göteborg (2006). [PDF]
  2. Elmqvist, N., Tsigas, P. A Taxonomy of 3D Occlusion Management Techniques. In Proceedings of the IEEE Conference on Virtual Reality 2007, to appear. [PDF]
  3. Assarsson, U., Elmqvist, N., Tsigas, P. Image-Space Dynamic Transparency for Improved Object Discovery in 3D Environments. Technical report CS:2006-10, Chalmers University of Technology, Göteborg (2006). [PDF]
  4. Elmqvist, N., Tudoreanu, E. Evaluating the Effectiveness of Occlusion Reduction Techniques for 3D Virtual Environments. In Proceedings of the ACM Symposium on Virtual Reality Software and Technology 2006, pp. 9-18 (2006). [PDF]
  5. Elmqvist, N., Tsigas, P. View Projection Animation for Occlusion Reduction. In Proceedings of the ACM Conference on Advanced Visual Interfaces 2006, pp. 471-475. [PDF]
  6. Elmqvist, N. BalloonProbe: Reducing Occlusion in 3D using Interactive Space Distortion. In Proceedings of the ACM Symposium on Virtual Reality Software and Technology 2005, pp. 134-137. [PDF]
  7. Elmqvist, N., Tsigas, P. Animated Visualization of Causal Relations Through Growing 2D Geometry. In Information Visualization, Vol. 3 (2004) No. 3, pp. 154--172 (Special Issue of Selected Papers from the ACM Symposium on Software Visualisation 2003), Palgrave Macmillan. [PDF]
  8. Elmqvist, N., Tsigas, P. CiteWiz: A Tool for the Visualization of Scientific Citation Networks. Technical report CS:2004-05, Chalmers University of Technology, Göteborg (2004). [PDF]
  9. Elmqvist, N., Tsigas, P. Causality Visualization Using Animated Growing Polygons. In Proceedings of the IEEE Symposium on Information Visualization 2003, pp. 189-196. [PDF]
  10. Elmqvist, N., Tsigas, P. Growing Squares: Animated Visualization of Causal Relations. In Proceedings of ACM 2003 Symposium on Software Visualization 2003, pp. 17-26. [PDF]