Slide 1 - Build Terrain

This exercise teaches you how to build terrain from a USGS DEM file. Instructions are provided as a series of numbered lists with conceptual descriptions where necessary. The instruction blocks suggest save or pause points.

Preparation Work

This series of instructions teaches you how to configure Scenome for terrain construction.

  1. Start the software.
  2. Select File » Save As from the main menu.
  3. Set the path and file name to \EXERCISES\BILLINGS_W\USER_BILLINGS_W_MASTER.BOX and click Save.
  4. Examine the hierarchy. This is a picture of the hierarchy.

Create A Preview Mesh

This series of instructions teaches you how to create a preview mesh from a DEM.

  1. Select Worksheet » Long Clip Plane from the main menu.
  2. Right click over the light node and select Delete from the listed options.
  3. Right click over the group node named Scene.
  4. Select File » Import DEMs for Elevation from the listed options. This displays the a dialog box: This is a picture of the Open dialog.
    NOTE: If necessary, set the current directory to \EXERCISES\BILLINGS_W. The correct directory has BILLINGS-W.DEM and a single directory named IMAGE_PROCESSING. We would like to apologize for this directory confusion but Windows might install the example files any number of different places depending on the location of your Application Data Folder.
  5. Left click BILLINGS_W.DEM and click Open.
  6. Examine the hierarchy: This is a picture of the hierarchy.
    NOTE: The software creates a preview group. This preview group contains a low resolution version of the terrain represented in BILLINGS-W.DEM. The preview group is created to help keep your scenery nicely organized.

Examine The Hierarchy In Depth

  1. Left click the small + to the left of the group node named ImportResults.
  2. You can see a group named Palette and a mesh named Lat: [45.00 to 46.00] Long: [-110.00 to -109.00].
  3. Left click the small + to the left of the group and mesh.
  4. The hierarchy looks like this: This is a picture of the hierarchy.
  5. Let's examine the hierarchy in detail.
    • ImportResults. Group node that organizes the preview geometry.
      • Cameras. Group node that contains two cameras.
        • Camera.Origin. Camera node centered over origin.
        • Camera.Terrain. Camera node centered over terrain.
      • Palette. Group node that contains the material palette for the mesh.
        • Lat: [45.00 to 46.00] Long: [-110.00 to -109.00]. Material node applied the RectangleGeometryModifier.
        • Lat: [45.00 to 46.00] Long: [-110.00 to -109.00]. Texture node referenced by the material node. Points at a texture on disk.
      • Lat: [45.00 to 46.00] Long: [-110.00 to -109.00]. Mesh node that contains construction history for the preview geometry.
        • ExportOptionsLayer. This modifier contains terrain generation settings.
        • OrthoImageryOptionsLayer. This modifier contains terrain generation settings.
        • GeometryLayer. Creates terrain geometry covering the latitude and longitude specified in the DEM file.
        • ElevationLayer. Displaces the mesh vertices along Z. Contains important displacement parameters as well.
        • GeographicProjectionLayer. Projects the geometry from simple world space into the coordinate space of the projection.
        • DynamicTextureLayer. Automagically generates a texture from a pool of GEOTIFFs and geographic metadata files.
        • CalculateLightingLayer. Generates lighting for the mesh.

Adjust Projection & Camera Position

  1. Examine the hierarchy.
  2. Right click the modifier named GeographicProjectionLayer.
  3. Select Lambert: Montana State Plane from the listed options.
  4. This configures the GeographicProjectionModifier to use Lambert Conformal Conic - a common map projection. Scenome also supports Universal Transverse Mercator projection and Robinson. More on those later.
  5. Select Worksheet » Global Edges from the main menu. [ ALT + W + E ]
  6. Left click the mesh named Lat: [45.00 to 46.00] Long: [-110.00 to -109.00].
  7. Select Worksheet » Camera » Camera: Find Terrain from the main menu.
  8. Right click on the camera node named Camera.Terrain and select Store Active View In Camera from the listed options.
  9. The worksheet looks like this: This is a picture of the worksheet.
  10. Left click the worksheet to deselect the mesh.
  11. Normally the instructions would tell you to navigate; for this exercise it's easier to give you a specific camera location.
  12. Select Worksheet » Properties from the main menu.
  13. Camera Settings is the first property group.
    • Set Camera Orientation X to 45 deg.
    • Set Camera Orientation Y to 0 deg.
    • Set Camera Orientation Z to 0 deg.
    • Set Camera Position X to 600000.
    • Set Camera Position Y to 70000.
    • Set Camera Position Z to 70000.
    • Set Near Clip to 10.
    • Set Far Clip to 250000. This will slow down the navigation. If it's too slow for your taste, increase the value to between 300000 and 400000 meters.
  14. The worksheet looks like this: This is a picture of the worksheet.
  15. That is a preview of a complete geocell.
    EXPLANATION: The geometry has been projected into Lambert Conformal Conic space. This mesh will be used to generate terrain. At present you can see the terrain is represented by a mesh containing 8×8 polygons. This means the terrain generation will create 8×8 output meshes. Don't worry if the terrain seems "low resolution"; that's the idea. The output terrain will have much more resolution.