     a and b must be declared as double precision 
               SpiceCells.
</PRE>
<h4><a name="Detailed_Output">Detailed_Output</a></h4>
<PRE>
 
   c           is the output CSPICE window, containing the difference 
               of a and b---every point contained in a, but not 
               contained in b. 

               c must be declared as a double precision SpiceCell.

               c must be distinct from both a and b. </PRE>
<h4><a name="Parameters">Parameters</a></h4>
<PRE>
 
   None. 
 </P