WHAT THE PRODUCT DOES

   XVision for windows allows the user to view volumetric datasets
using "Direct Volume Rendering".  Simply put, this gives the user
XRay vision.  He/She can see the surface, but can also see through
the surface to the structures underneath.

   This (relatively new) type of graphics is used to view volume
data such as that provided by Cat Scan (CT) Machines and Magnetic
Resonance Imaging (MRI).  It is also used to view structures at the
cellular level and genetic levels using Fluorescent Microscopy and
other technologies.

   The product is called a "Volumetric Ray Tracer" and requires 
that a simulation of the interaction of light with the semi-
transparent volume data must be calculated.  This is extremely
computationally expensive.  Every attempt (short of resorting
to assembler for strategic modules) has been made to boost
rendering speeds while keeping memory consumption to a minimum.


HARDWARE REQUIREMENTS

  - A 486 or better processor (pentium preferred)
  - A Mouse
  - A Graphics card capable of better than 256 colors
  - Windows 3.1
  - 4 MB of memory (8 MB to render the CT dataset provided)


TO INSTALL XVISION FOR WINDOWS

   1)  mkdir c:\xvision (or some other directory of your choice)
   2)  Use pkunzip to decompress the downloaded file.  This
	utility can be found on compuserve.
	   - copy xvision.zip c:\xvision
	   - del xvision.zip
	   - cd c:\xvision
	   - Type "pkunzip xvision.zip"
   3)  Place all the uncompressed files into c:\xvision
   4)  Start Windows (if necessary)
   5)  Choose file->new from the program manager menu
   6)  Choose "program item" and press "OK"
   7)  Fill out the program item properties dialog box as follows:

		Description:		Xvision for Windows
		Command Line:		c:\xvision\xvision
		Working Directory:	c:\xvision
		Shortcut Key:		None
		Run Minimized:		Leave Option Off

   8)  Press "OK"


EXAMPLE PROGRAM INTERACTION

   1)  Double click on the "Xvision for Windows" icon to run the program.
   2)  Double click on the "mlti_clr.dat" file in the file selection box
	at the left.
   3)  Press some of the rotate keys at the bottom right to fly about the
	(currently empty) volumetric dataset.
   4)  Select "Define->volume" to allow viewing of the volumetric dataset.
   5)  Double click on the "multi_clr.dat" file again.  The volume data
	will be displayed in the display window after a short pause.
	Now press "expand" to view the data at a large size.  Note that
	as the size increases, so does rendering time.


Notes:

   - The "Define->extents only" menu entry is on by default.  The
	define->volume menu item allows viewing of the volumetric
	dataset.  The "Extent Cues" menu defines whether the extents
	(i.e., edges) and the x/z axes are displayed in the viewing
	window.

   - One low-resolution non-artificial dataset has been included in the
	distribution.  See the file "realdata.dat".  This is a Cat Scan
	of a human head.  With some practice, you should be able to
	effectively explore the data.  I will download the same dataset
	at a higher resolution if someone wants it.  It is 7MB large
	and viewing it requires 16 MB of memory.

   - The dive/surface buttons can be used to uniformly bias the transparency
	levels of the contents of the volume allowing the user to see data
	at different depth in the volume.

   - Use the "extents only" mode to find an appropriate viewing angle 
	quickly.  When you think you are at or close to an appropriate
	viewing angle, slip into volume mode for one frame to check it
	out.  Keep the size (via the expand/shrink buttons) down until
	you have honed down on the appropriate opacity and viewing
	angle.


KNOWN FEATURES/BUGS

  1)   Multitasking will not occur when the data files are loading (this
	will not be noticed when using the artificial datasets).  The system
	may appear to lock up momentarily.

  2)  Slower processors (less than pentium) may cause windows to respond
	slowly to interface events while xvision is rendering large
	datasets.

Please report bugs and suggest features by sending mail to the CIS ID
on the datafile that you downloaded or to "INTERNET:rmorris@playmate.mv.com".