File I/O: 
1)  From the VolVis panel, press ``File I/O'' and a “File I/O” panel will pop up. 
2)  On the “File I/O” panel, press ``Load'' and a “File Load” panel will pop up.
3)  Select a .slc file from list. 
4)  Press "Accept" to Load it. Press "Close" to close “File Load” panel.
5)  To save images, press "Save" on the “File I/O” panel and click on the image in the right window you want to save and specify the path and name and “Accept”.

         fig.1

Object Control:

• Press ``Object Control'', "Object Control" panel popped up.
• Use pull-down menu to set the ``Active Objects'' to be ``Volume''. Select the object you loaded and you want to adjust. Press ``Modify'' button and an object modification panel will pop up. You may “delete” objects from “Object Control” panel, too.
• Select "color"->"single color" to modify the color of the object. "Color Array" is for using transfer function. We will explain it later.
• Do "Segmentation" from the “modify ... Segmentation" panel. Choose "Isosurface" to adjust the isovalue for isosurface rendering, or "Scalar Opacity" to adjust the transfer function as shown in fig. 7 . 
• If you choose "color array", four curves corresponding to the 3 colors and opacity appear in this window and by choosing different " Edit Function", you may adjust the transfer function of Opacity, R,G,B respectively.
• To adjust position of the light source, set 'Active Objects' to be lights and select any of the given light sources. Pressing 'Modify' pops up a window that lets you adjust the x,y,z coordinates and the intensity of the lightsource. 

                 fig.  3

                              fig.  7

Renderer:
    On the "Renderer" panel, choose  ``Ray Trace'', press "Setup" to change the setup parameters of rendering.  Press ``Project'' to render the image. Before rendering, use the Navigator to set the viewing parameters (see below).

                                           fig. 9

  fig. 8 ( see file save how to save the image)

Navigator:
   The navigator is used to adjust the view parameters and to preview the image you want to render at a lower quality.  There are two ways to use this tool: 

• On the 'Navigator' panel, click on the 'Manual Control' button to pop up a navigator control window, which allows you to adjust  viewing parameters like translating and rotating variables. Click on `Projection1' or the other two buttons to project from the corresponding nav_view. 
• Alternatively (and probably better) use the tools provided in the nav_view (the one you get if you hit 'Projection 1''). You see  two select  windows: one is set to 'Marching Cubes' (set this one to 'Raytrace'), the other is set to 'Fly'.  Next to the window you see a velocity slider labeled 'V'. In 'Fly' mode you can interactively fly around the object. Click the left mouse button in the window and move the mouse in the window. You will notice that the object follows the mouse and flies either towards you or away from you (depending on the setting of the velocity slider 'V'). Click again to stop the flying. If instead of 'Fly' you select 'Translate/Rotate (Mod)', then you can click the left mouse button in the display window to initiate translation or the middle mouse button (or left and right mouse button pressed together for a 2-button mouse) to initiate rotation. The object will then follow your mouse movements. Click the mouse again to stop the transformations. 

                                                      fig. 11

     After adjusting the parameters, don't close the navigator Control window, click on 'project' on the render panal to see the effect.

                    fig.  10