ungrasp - a filter for importing GRASP surface files into Raster3D
	  Fortran source distributed as part of Raster3D

This directory contains a utility program "ungrasp" which will convert a
simple GRASP V1.1 surface file into a list of Raster3D objects.  
Similar conversion routines could of course be written for other surface
generation programs.

I hope that the new (version 2.2) support in Raster3D for transparent
surfaces will encourage the developers of programs such as GRASP to 
include an option for direct output of Raster3D files, but for now I have
to make due with non-ideal conversion utilities like this one.  

Here is a list of known problems:

- You must select the "absolute centering" option when you save the GRASP
  surface.  That is the only way to preserve the original PDB coordinates
  associated with the stored surface.

- ungrasp does not know about all the possible types of information stored
  in a GRASP surface file.  Currently it can only deal with stored potentials
  and discrete color indexes.

- The ungrasp utility must be compiled and run on the same architecture machine
  as your GRASP executable.  I believe that means SGI only, but I could be
  wrong.

    GRASP reference:
	Anthony Nicholls, Kim Sharp and Barry Honig, PROTEINS,
 	Structure, Function and Genetics, Vol. 11, No.4, 1991, pg. 281ff
    GRASP homepage:
	http://tincan.bioc.columbia.edu/Lab/grasp/

Ethan A Merritt - 8 Feb 1996

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18 Mar 1998
	The ungrasp code has been updated to use per-vertex colors
	(object type 17) in Raster3D V2.4d
 7 May 1998
	And now it works for coloring by potential also
