WELCOME to The BEATING HEART DEMO


   Data Courtesy of:

   Dr. Stephan Nekolla                         
   Leiter Medizinische Datenverarbeitung      
   Klinik und Poliklinik fuer Nuklearmedizin 
   Klinikum rechts der Isar der Technischen
   Universitaet Muenchen 
   Ismaningerstr. 22 D-81675 Muenchen


   Generating the Heart:
   ---------------------
   The heart geometry is generated from triangulating
   an array of points into a series of quad polygons.
   Each step in the sequence of the beating heart
   consists of 3 parts: Inner Surface, Outer Surface,
   and Bottom (connecting) surface.

   The colors are determined using a color lookup
   value from a 3D array of perfusion values stored
   for every point. The object geometry representing
   the heart is manipulated based on the data for each
   of the above steps to show the shape of the heart
   through one heartbeat cycle.

   
   IDL Features:
   -----------------
   This demo uses the following features from IDL 
   Object Graphics:

   o  Interactive 3D graphics to control the object 
      transformation (rotation) with the mouse.

   o  Geometry creation using "IDLgrPolygon" and
      "IDLgrPolyline" to represent the heart light
      source icons.

   o  Light source shading, using 2 "Positional" 
      light sources.



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

   File Menu:
      Select "Quit" to exit the Beating Heart Demo and 
      return to the IDL Demo main screen.

   Options Menu:
   
      Shading
      Select either Flat or 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
      Select either Wire or Solid to represent the 
      surface of the heart.

      Drag Quality
      Select either Low or High quality for when you
      rotate the solid by dragging the mouse. Low 
      quality shows a wire surface when dragging while
      High quality retains the surface displayed.

   Help Menu:
      Select "About Beating Heart" for information about
      the Beating Heart Demo.


   FEATURES
   --------

   <<OBJECT VISIBILITY>> checklist   

   Select one or all of the following choices for 
   displaying the heart. A check next to the item 
   specifies that it is enabled.

   o  Outer surface
   o  Inner surface
   o  Bottom surface
   o  Axis 3D
   o  Light icons
   o  Annotations


   <<Start>> button
      Starts the sequence of steps showing the heart
      through one heartbeat cycle.

   <<Step>> button
      Displays each step in order.

   <<Reset Orientation>> button
      Reset the heart to its initial orientation.


   INTERACTIVE MOVEMENT
      Use your left mouse button to interactively 
      rotate the heart. Position the cursor on the 
      image and, while holding down the left mouse 
      button, move the cursor to rotate the heart. 
      Release the mouse button when you are satisfied 
      with the position of the heart.