NAME
          DtNurbsGetTrimVertices - Get the trim vertices for the given
          NURBS surface.


     SYNOPSIS
          #include <Dt.h>


          int  DtNurbsGetTrimVertices( int shapeID, int groupID, int *count, DtVec2f **vertices )


     DESCRIPTION
          DtNurbsGetTrimVertices() returns the array of trim vertices
          in the NURBS surface, via the pointer to the variable
          vertices. The number of vertices in the surface is returned
          via the pointer to count. The vertices are for the shapeID
          and group groupID. This array is an internal buffer.  Do not
          free or modify the trim vertex array.  C programmers can
          access the components of the trim vertex array as though it
          were a simple structure as follows:

          typedef struct DtVec2f { float vec[2];};

          DtVec2f *tVerts;

          DtNurbsGetTrimVertices( shapeID, int groupID, int *count,
          &tVerts);

          /* The first trim vertex */
          x = tVerts[0].vec[0];
          y = tVerts[0].vec[1];

     IMPLEMENTATION
          The AliasAPI implementation of Dt does not support any
          NURBS geometry.  No NURBS geometry will be returned by this
          function.


     DIAGNOSTICS
          DtNurbsGetTrimVertices() returns one on success and zero on
          failure.


     FILES
          Link with -lDtOMio