EVL Internal Visualization Workshop
May 25th and 26th, 2004

Cavern group

Version: June 1, 2004

ResearchGear ID: 20040525_renambot

    Findings about SAGE:
  1. There are sufficient similarities in JuxtaView and Vol-a-Tile that in the next generation design, a single framework should be able to support both requirements.
  2. This framework will be called SAGE- the Scalable Adaptive Graphics Environment.
  3. SAGE will consist of two major components: a rendering component, and a display management component.
    • The rendering component deals with the conversion of raw data into visualizations.
    • The display management component deals with the routing of the rendered pixels to the displays themselves.
    • This model permits both localized and remote rendering and multicasting for collaborative work.
  4. To support rendering of ever growing data sizes SAGE must adopt multi-resolution techniques using some form of compression mechanism such as those in JPEG2000 using wavelets, or use a technique similar to mipmapping. Furthermore view-dependent rendering techniques must be used to help reduce the portion of the data that is in the visible view frustum.
  5. To support time-varying data sets, Time Space Partitioning trees (TSP) should be used to encapsulate both geometry and time. However significant modification of the TSP concept must be made to accommodate the various multi-resolution and view-dependent compression mechanisms.
  6. At some point, the data sets will simply be too large to render in real time. In this case, real time rendering will only be used to give the viewer a low resolution image that the user can manipulate. Then, as the user releases control to SAGE, rendering will use either ray casting or sort-last rendering algorithms to fill in the details. Visual effects such as gradually fading between the higher resolution and the lower resolution images can be used to reduce any abrupt transition between the two levels of detail.
  7. A scene graph hierarchy is needed to manage collections of TSPs. Each TSP would represent one data object that needs to be rendered. Singe geosciences data sets usually come in multiple layers/dimensions, one would need multiple TSPs- one per layer. Each of these TSP layers could conceivably be rendered separately and composited using sort-last rendering when rendering in full resolution mode.
  8. SAGE’s display manager should also be able to support incoming AccessGrid video streams and integrate them as part of the visualization environment.
  9. Targeted display devices for SAGE are
    • GeoWalls,
    • GeoWall2s,
    • Personal GeoWall 2s,
    • Varriers.


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