Exercise Three

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To become familiar with the capabilities of the Map Editor and the Render module, including

  • Deleting modules
  • Saving and loading maps
  • Changing properties of the rendered scene
  • Viewing and picking


  1. In the map created during Exercise Two, select WireFrame and break all its connections. What happens to the display in Render? Restore its connections, then delete the module. Save the map as a file called zigzag.map, then delete all the modules in the map.
  2. Load the flythru map from the Librarian. This uses the same input data, but displays it as a coloured surface. The camera used to view the scene in Render can be taken along a previously stored path using the AnimateCamera module. Press the Go button on AnimateCamera to start the animation.
  3. Delete all the modules in the map and reload your map from zigzag.map. Does it still work?
  4. Delete all the modules in the map and load the flowpath map. This reads in a 3D vector dataset as a 3D perimeter lattice and displays it using particle advection, performed by NAGAdvectAnimate. Use the mouse in the Render window to manipulate the camera in the scene.
  5. Experiment with any of the following using the NAGAdvectAnimate control panel: changing the location and size of the probe volume (try X Low = 0.5, Y Low = 0.1, X Size = 0.8, Y Size = 4.0), the number of particles (try Number = 20), the distribution of particles (try Distribution = Ring XY Plane), or the display options (try Streak Type = Spheres, Repeat = Yes, Distance = 2). Note that changing any of the parameters causes the module to re-fire; you can prevent this by setting Mode to Build, making the changes and then setting it back to Run.
  6. Delete all the modules in the map and load the ruler map. This reads in a 3D scalar dataset as a 3D uniform lattice and displays it using an isosurface. Use the thumbwheels at the edge of the Render window to control the camera in the scene. (If the thumbwheels are missing, bring them up using the Decoration option on the Render pop-up menu.)
  7. The Ruler module in this map does interpolation on the data between two user-defined endpoints and passes the data values (as a 1D uniform lattice) to the NAGGraph module for display. Experiment with changing the location of the endpoints using the dials on the Ruler control panel, and watch the display of the interpolated values change.
  8. Delete Ruler and NAGGraph from this map, and restore the original camera position by refiring the ReadGeom module (so that it is read from $EXPLORERHOME/data/camera/ruler.cam.iv). Pull down the Lights menu and select Edit from the Headlight cascaded menu to bring up the Headlight Editor. Use the Headlight Editor to manipulate the direction of the light in the scene.
  9. Now put Render into Picking mode by pressing the <Esc> key when the mouse is over the drawing area. Now objects which are selected can be edited. Select the isosurface using the left-hand mouse button when over any part of the surface. Pull down the Editors menu and select Material Editor... to bring up the Material Editor. Experiment with changing some of the properties of the surface. Can you change its colour? Can you make it very shiny? Can you make it bright? Can you make it transparent? Experiment with the different types of transparency in the View menu.

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© The Numerical Algorithms Group Ltd. Oxford, UK. 2000