THREE DIMENSIONAL GEOMETRY DEMO
   
   This demo shows geometric forms and molecules.
   Choose among several different 3D objects.


   MENU OPTIONS
   ------------

   File Menu:
      Select "Quit" to exit the 3D Object Demo and return 
      to the IDL Demo main screen.

   Options Menu:
   
      Shading
      o  Select "Flat" to represent solid objects. 
      o  Select "Gouraud" shading for the solid. 
         Gouraud shading results in a more realistic 
         appearance.
         
         Shading is only enabled when the Style is set 
         to Solid.

      Style
      o  Select "Points" to display the object as a set
         of points.
      o  Select "Wire" to display the object with a 
         wire-frame surface.
      o  Select "Solid" to display the object as a 
         solid. You can also select either "Flat" or 
         "Gouraud" shading.
      o  Select "Hidden Points" to display only the 
         points located immediately in front.
      o  Select "Hidden Wire" to display only the lines
         of the wire-surface located immediately in 
         front.
   
      Backface culling
         Select this option (turn it "on") to only 
         show the outside surface of the objects,
         making inner surfaces transparent.

      Vertex coloring
         Select this option (turn it "on") to display
         the object with predetermined colors.

      Edging
         Select this option (turn it "on") to show the
         polygon edges of the object. This option is 
         the most effective when viewed with the 
         "Solid" style.

      Bottom color
         Select this option (turn it "on") to 
         differentiate inner surfaces with a separate 
         color.

      Line thickness
         Select the line thickness (1, 3, 5 or 7 
         points). This option is disabled when the 
         style is set to "Solid".

      Drag quality
         Drag quality applies only to solid surfaces.
         o  Select "Low" to show the dragged image as 
            a single-color wire-frame object.
         o  Select "Medium" to show the dragged image 
            as a "Flat" object, even if the Shading is 
            already set to "Flat".
         o  Select "High" to show the dragged image as
            it is shown.

         The higher the drag quality, the slower the 
         speed of rendering the object. You may or may
         not see a difference, depending on your 
         machine's speed.

   About Menu:   
      Select "About 3D Geometry" for information about 
      the 3D Geometry Demo.


   FEATURES
   --------

   <<Seashell>> radio button
      Shows a seashell-shaped object.

   <<Knot>> radio button
      Shows a pretzel-like knot object.

   <<Teapot>> radio button
      Shows a teapot-shaped object.   

   <<Valium Molecule>> radio button
      Shows a valium molecule.   

   <<Aspartame>> radio button
      Shows an aspartame molecule.

   <<Caffeine>> radio button
      Shows a caffeine molecule.

   <<Reset Orientation>> button
      Return the object to its initial orientation.

   INTERACTIVE MOVEMENT
      Use your left mouse button to interactively 
      rotate (drag) the selected object. Position the 
      cursor on the object and, while holding down the
      left mouse button, move the cursor. Release the 
      mouse button when you are satisfied with the 
      position of the object. 
 
      For solid objects, you can also specify the Drag
      Quality, which affects the object's appearance
      while it is being dragged. If you find that 
      dragging the object is slow, lower the 
      Drag Quality.