NRBKNTPLOT: Plot a NURBS entity with the knots subdivision.
Calling Sequence:
nrbkntplot(nurbs)
nrbkntplot(nurbs, npnts)
INPUT:
nurbs: NURBS curve, surface or volume, see nrbmak.
npnts: Number of evaluation points, for a surface or volume, a row
vector with the number of points along each direction.
Example:
Plot the test surface with its knot vector
nrbkntplot(nrbtestsrf)
See also:
nrbctrlplot
Copyright (C) 2011, 2012, 2021 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 3 of the License, or
(at your option) any later version.
Demonstration 1
The following code
crv = nrbtestcrv;
nrbkntplot(crv)
title('Test curve')
hold off
Produces the following figure
| Figure 1 |
|---|
 |
Demonstration 2
The following code
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
Produces the following figure
| Figure 1 |
|---|
 |
Demonstration 3
The following code
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);
Produces the following figure
| Figure 1 |
|---|
 |
Package: nurbs