--- /dev/null
+function nrbkntplot (nurbs)
+
+% NRBKNTPLOT: Plot a NURBS entity with the knots subdivision.
+%
+% Calling Sequence:
+%
+% nrbkntplot(nurbs)
+%
+% INPUT:
+%
+% nurbs: NURBS curve, surface or volume, see nrbmak.
+%
+% Example:
+%
+% Plot the test surface with its knot vector
+%
+% nrbkntplot(nrbtestsrf)
+%
+% See also:
+%
+% nrbctrlplot
+%
+% Copyright (C) 2011 Rafael Vazquez
+%
+% 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 2 of the License, or
+% (at your option) any later version.
+
+% This program is distributed in the hope that it will be useful,
+% but WITHOUT ANY WARRANTY; without even the implied warranty of
+% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+% GNU General Public License for more details.
+%
+% You should have received a copy of the GNU General Public License
+% along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+if (nargin < 1)
+ error ('nrbkntplot: Need a NURBS to plot!');
+end
+
+% Default values
+light='on';
+cmap='summer';
+
+colormap (cmap);
+
+hold_flag = ishold;
+
+if (iscell (nurbs.knots))
+ if (size (nurbs.knots,2) == 2) % plot a NURBS surface
+ nsub = 100;
+ nrbplot (nurbs, [nsub nsub], 'light', light, 'colormap', cmap);
+ hold on
+
+ % And plot the knots
+ knt1 = unique (nurbs.knots{1});
+ knt2 = unique (nurbs.knots{2});
+ p1 = nrbeval (nurbs, {knt1, linspace(0.0,1.0,nsub)});
+ p2 = nrbeval (nurbs, {linspace(0.0,1.0,nsub), knt2});
+
+ if (any (nurbs.coefs(3,:)))
+ % surface in a 3D space
+ for ii = 1:numel(knt1)
+ plot3 (squeeze(p1(1,ii,:)), squeeze(p1(2,ii,:)), squeeze(p1(3,ii,:)));
+ end
+ for ii = 1:numel(knt2)
+ plot3 (squeeze(p2(1,:,ii)), squeeze(p2(2,:,ii)), squeeze(p2(3,:,ii)));
+ end
+ else
+ % plain surface
+ for ii = 1:numel(knt1)
+ plot (squeeze(p1(1,ii,:)), squeeze (p1(2,ii,:)));
+ end
+ for ii = 1:numel(knt2)
+ plot (p2(1,:,ii),p2(2,:,ii));
+ end
+ end
+
+
+
+ elseif (size (nurbs.knots,2) == 3) % plot a NURBS volume
+ nsub = 30;
+ nrbplot (nurbs, [nsub nsub nsub], 'light', light, 'colormap', cmap);
+ hold on
+
+ % And plot the knots
+ knt1 = unique (nurbs.knots{1});
+ knt2 = unique (nurbs.knots{2});
+ knt3 = unique (nurbs.knots{3});
+ kv_face1 = nrbeval (nurbs, {0, knt2, linspace(0.0,1.0,nsub)});
+ kw_face1 = nrbeval (nurbs, {0, linspace(0.0,1.0,nsub), knt3});
+ kv_face2 = nrbeval (nurbs, {1, knt2, linspace(0.0,1.0,nsub)});
+ kw_face2 = nrbeval (nurbs, {1, linspace(0.0,1.0,nsub), knt3});
+ ku_face3 = nrbeval (nurbs, {knt1, 0, linspace(0.0,1.0,nsub)});
+ kw_face3 = nrbeval (nurbs, {linspace(0.0,1.0,nsub), 0, knt3});
+ ku_face4 = nrbeval (nurbs, {knt1, 1, linspace(0.0,1.0,nsub)});
+ kw_face4 = nrbeval (nurbs, {linspace(0.0,1.0,nsub), 1, knt3});
+ ku_face5 = nrbeval (nurbs, {knt1, linspace(0.0,1.0,nsub), 0});
+ kv_face5 = nrbeval (nurbs, {linspace(0.0,1.0,nsub), knt2, 0});
+ ku_face6 = nrbeval (nurbs, {knt1, linspace(0.0,1.0,nsub), 1});
+ kv_face6 = nrbeval (nurbs, {linspace(0.0,1.0,nsub), knt2, 1});
+
+ for ii = 1:numel(knt1)
+ plot3 (squeeze (ku_face3(1,ii,:,:)), squeeze (ku_face3(2,ii,:,:)), squeeze (ku_face3(3,ii,:,:)));
+ plot3 (squeeze (ku_face4(1,ii,:,:)), squeeze (ku_face4(2,ii,:,:)), squeeze (ku_face4(3,ii,:,:)));
+ plot3 (squeeze (ku_face5(1,ii,:,:)), squeeze (ku_face5(2,ii,:,:)), squeeze (ku_face5(3,ii,:,:)));
+ plot3 (squeeze (ku_face6(1,ii,:,:)), squeeze (ku_face6(2,ii,:,:)), squeeze (ku_face6(3,ii,:,:)));
+ end
+ for ii = 1:numel(knt2)
+ plot3 (squeeze (kv_face1(1,:,ii,:)), squeeze (kv_face1(2,:,ii,:)), squeeze (kv_face1(3,:,ii,:)));
+ plot3 (squeeze (kv_face2(1,:,ii,:)), squeeze (kv_face2(2,:,ii,:)), squeeze (kv_face2(3,:,ii,:)));
+ plot3 (squeeze (kv_face5(1,:,ii,:)), squeeze (kv_face5(2,:,ii,:)), squeeze (kv_face5(3,:,ii,:)));
+ plot3 (squeeze (kv_face6(1,:,ii,:)), squeeze (kv_face6(2,:,ii,:)), squeeze (kv_face6(3,:,ii,:)));
+ end
+ for ii = 1:numel(knt3)
+ plot3 (squeeze (kw_face1(1,:,:,ii)), squeeze(kw_face1(2,:,:,ii)), squeeze (kw_face1(3,:,:,ii)));
+ plot3 (squeeze (kw_face2(1,:,:,ii)), squeeze(kw_face2(2,:,:,ii)), squeeze (kw_face2(3,:,:,ii)));
+ plot3 (squeeze (kw_face3(1,:,:,ii)), squeeze(kw_face3(2,:,:,ii)), squeeze (kw_face3(3,:,:,ii)));
+ plot3 (squeeze (kw_face4(1,:,:,ii)), squeeze(kw_face4(2,:,:,ii)), squeeze (kw_face4(3,:,:,ii)));
+ end
+ end
+
+else % plot a NURBS curve
+ nsub = 1000;
+ nrbplot (nurbs, nsub);
+ hold on
+
+ % And plot the knots
+ p = nrbeval (nurbs, unique (nurbs.knots));
+
+ if (any (nurbs.coefs(3,:))) % plot a 3D curve
+ plot3 (p(1,:), p(2,:), p(3,:), 'x');
+ else % plot a 2D curve
+ plot (p(1,:), p(2,:), 'x');
+ end
+
+end
+
+if (~hold_flag)
+ hold off
+end
+
+end
+%!demo
+%! crv = nrbtestcrv;
+%! nrbkntplot(crv)
+%! title('Test curve')
+%! hold off
+
+%!demo
+%! sphere = nrbrevolve(nrbcirc(1,[],0.0,pi),[0.0 0.0 0.0],[1.0 0.0 0.0]);
+%! nrbkntplot(sphere);
+%! title('Ball and torus - surface construction by revolution');
+%! hold on;
+%! torus = nrbrevolve(nrbcirc(0.2,[0.9 1.0]),[0.0 0.0 0.0],[1.0 0.0 0.0]);
+%! nrbkntplot(torus);
+%! hold off
+
+%!demo
+%! knots = {[0 0 0 1/2 1 1 1] [0 0 0 1 1 1]...
+%! [0 0 0 1/6 2/6 1/2 1/2 4/6 5/6 1 1 1]};
+%!
+%! coefs = [-1.0000 -0.9734 -0.7071 1.4290 1.0000 3.4172
+%! 0 2.4172 0 0.0148 -2.0000 -1.9734
+%! 0 2.0000 4.9623 9.4508 4.0000 2.0000
+%! 1.0000 1.0000 0.7071 1.0000 1.0000 1.0000
+%! -0.8536 0 -0.6036 1.9571 1.2071 3.5000
+%! 0.3536 2.5000 0.2500 0.5429 -1.7071 -1.0000
+%! 0 2.0000 4.4900 8.5444 3.4142 2.0000
+%! 0.8536 1.0000 0.6036 1.0000 0.8536 1.0000
+%! -0.3536 -4.0000 -0.2500 -1.2929 1.7071 1.0000
+%! 0.8536 0 0.6036 -2.7071 -1.2071 -5.0000
+%! 0 2.0000 4.4900 10.0711 3.4142 2.0000
+%! 0.8536 1.0000 0.6036 1.0000 0.8536 1.0000
+%! 0 -4.0000 0 0.7071 2.0000 5.0000
+%! 1.0000 4.0000 0.7071 -0.7071 -1.0000 -5.0000
+%! 0 2.0000 4.9623 14.4142 4.0000 2.0000
+%! 1.0000 1.0000 0.7071 1.0000 1.0000 1.0000
+%! -2.5000 -4.0000 -1.7678 0.7071 1.0000 5.0000
+%! 0 4.0000 0 -0.7071 -3.5000 -5.0000
+%! 0 2.0000 6.0418 14.4142 4.0000 2.0000
+%! 1.0000 1.0000 0.7071 1.0000 1.0000 1.0000
+%! -2.4379 0 -1.7238 2.7071 1.9527 5.0000
+%! 0.9527 4.0000 0.6737 1.2929 -3.4379 -1.0000
+%! 0 2.0000 6.6827 10.0711 4.0000 2.0000
+%! 1.0000 1.0000 0.7071 1.0000 1.0000 1.0000
+%! -0.9734 -1.0000 -0.6883 0.7071 3.4172 1.0000
+%! 2.4172 0 1.7092 -1.4142 -1.9734 -2.0000
+%! 0 4.0000 6.6827 4.9623 4.0000 0
+%! 1.0000 1.0000 0.7071 0.7071 1.0000 1.0000
+%! 0 -0.8536 0 0.8536 3.5000 1.2071
+%! 2.5000 0.3536 1.7678 -1.2071 -1.0000 -1.7071
+%! 0 3.4142 6.0418 4.4900 4.0000 0
+%! 1.0000 0.8536 0.7071 0.6036 1.0000 0.8536
+%! -4.0000 -0.3536 -2.8284 1.2071 1.0000 1.7071
+%! 0 0.8536 0 -0.8536 -5.0000 -1.2071
+%! 0 3.4142 7.1213 4.4900 4.0000 0
+%! 1.0000 0.8536 0.7071 0.6036 1.0000 0.8536
+%! -4.0000 0 -2.8284 1.4142 5.0000 2.0000
+%! 4.0000 1.0000 2.8284 -0.7071 -5.0000 -1.0000
+%! 0 4.0000 10.1924 4.9623 4.0000 0
+%! 1.0000 1.0000 0.7071 0.7071 1.0000 1.0000
+%! -4.0000 -2.5000 -2.8284 0.7071 5.0000 1.0000
+%! 4.0000 0 2.8284 -2.4749 -5.0000 -3.5000
+%! 0 4.0000 10.1924 6.0418 4.0000 0
+%! 1.0000 1.0000 0.7071 0.7071 1.0000 1.0000
+%! 0 -2.4379 0 1.3808 5.0000 1.9527
+%! 4.0000 0.9527 2.8284 -2.4309 -1.0000 -3.4379
+%! 0 4.0000 7.1213 6.6827 4.0000 0
+%! 1.0000 1.0000 0.7071 0.7071 1.0000 1.0000
+%! -1.0000 -0.9734 0.2071 2.4163 1.0000 3.4172
+%! 0 2.4172 -1.2071 -1.3954 -2.0000 -1.9734
+%! 2.0000 4.0000 7.0178 6.6827 2.0000 0
+%! 1.0000 1.0000 1.0000 0.7071 1.0000 1.0000
+%! -0.8536 0 0.3536 2.4749 1.2071 3.5000
+%! 0.3536 2.5000 -0.8536 -0.7071 -1.7071 -1.0000
+%! 1.7071 4.0000 6.3498 6.0418 1.7071 0
+%! 0.8536 1.0000 0.8536 0.7071 0.8536 1.0000
+%! -0.3536 -4.0000 0.8536 0.7071 1.7071 1.0000
+%! 0.8536 0 -0.3536 -3.5355 -1.2071 -5.0000
+%! 1.7071 4.0000 6.3498 7.1213 1.7071 0
+%! 0.8536 1.0000 0.8536 0.7071 0.8536 1.0000
+%! 0 -4.0000 1.2071 3.5355 2.0000 5.0000
+%! 1.0000 4.0000 -0.2071 -3.5355 -1.0000 -5.0000
+%! 2.0000 4.0000 7.0178 10.1924 2.0000 0
+%! 1.0000 1.0000 1.0000 0.7071 1.0000 1.0000
+%! -2.5000 -4.0000 -0.5429 3.5355 1.0000 5.0000
+%! 0 4.0000 -1.9571 -3.5355 -3.5000 -5.0000
+%! 2.0000 4.0000 8.5444 10.1924 2.0000 0
+%! 1.0000 1.0000 1.0000 0.7071 1.0000 1.0000
+%! -2.4379 0 -0.0355 3.5355 1.9527 5.0000
+%! 0.9527 4.0000 -1.4497 -0.7071 -3.4379 -1.0000
+%! 2.0000 4.0000 9.4508 7.1213 2.0000 0
+%! 1.0000 1.0000 1.0000 0.7071 1.0000 1.0000];
+%! coefs = reshape (coefs, 4, 4, 3, 9);
+%! horseshoe = nrbmak (coefs, knots);
+%! nrbkntplot (horseshoe);