NRBCOONS: Construction of a Coons patch.
 
 Calling Sequence:
 
   srf = nrbcoons(ucrv1, ucrv2, vcrv1, vcrv2)
 
 INPUT:
 
   ucrv1	: NURBS curve defining the bottom U direction boundary of
 		the constructed NURBS surface.
 
   ucrv2	: NURBS curve defining the top U direction boundary of
 		the constructed NURBS surface.
 
   vcrv1	: NURBS curve defining the bottom V direction boundary of
 		the constructed NURBS surface.
 
   vcrv2	: NURBS curve defining the top V direction boundary of
 		the constructed NURBS surface.

 OUTPUT:
 
   srf		: Coons NURBS surface patch.
 
 Description:
 
   Construction of a bilinearly blended Coons surface patch from four NURBS
   curves that define the boundary.
 
   The orientation of the four NURBS boundary curves.
 
          ^ V direction
          |
          |     ucrv2
          ------->--------
          |              |
          |              |
    vcrv1 ^   Surface    ^ vcrv2
          |              |
          |              |
          ------->-----------> U direction
                ucrv1
 
 
 Examples:
 
   // Define four NURBS curves and construct a Coons surface patch.
   pnts = [ 0.0  3.0  4.5  6.5 8.0 10.0;
            0.0  0.0  0.0  0.0 0.0  0.0; 
            2.0  2.0  7.0  4.0 7.0  9.0];   
   crv1 = nrbmak(pnts, [0 0 0 1/3 0.5 2/3 1 1 1]);
 
   pnts= [ 0.0  3.0  5.0  8.0 10.0;
           10.0 10.0 10.0 10.0 10.0;
           3.0  5.0  8.0  6.0 10.0];
   crv2 = nrbmak(pnts, [0 0 0 1/3 2/3 1 1 1]);
 
   pnts= [ 0.0 0.0 0.0 0.0;
           0.0 3.0 8.0 10.0;
           2.0 0.0 5.0 3.0];
   crv3 = nrbmak(pnts, [0 0 0 0.5 1 1 1]);
 
   pnts= [ 10.0 10.0 10.0 10.0 10.0;
           0.0   3.0  5.0  8.0 10.0;
           9.0   7.0  7.0 10.0 10.0];
   crv4 = nrbmak(pnts, [0 0 0 0.25 0.75 1 1 1]);
 
   srf = nrbcoons(crv1, crv2, crv3, crv4);
   nrbplot(srf,[20 20],220,45);

    Copyright (C) 2000 Mark Spink

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

Demonstration 1

Package: nurbs