Selecting the Points

This example will show how to draw a smooth curve through a list of points, in the order in which they occur. First, we select some random points in the plane, and store them in a matrix, one point percolumn.

npts = 10; xy = [randn(1,npts); randn(1,npts)]; plot(xy(1,:),xy(2,:),'ro','LineWidth',2); text(xy(1,:), xy(2,:),[repmat(' ',npts,1), num2str((1:npts)')]) ax = gca; ax.XTick = []; ax.YTick = [];

Connecting the Points

Next, construct the curve using thecscvncommand and plot it usingfnplt.

holdonfnplt(cscvn(xy),'r',2) holdoff

You could also use thegetcurvecommand if you wanted to input the list of points interactively.

3-D Spline Curves

It's just as easy to create spline curves in three dimensions. This time, we'll do something less random. First, we generate the points.

《不扩散核武器条约》= 13;t = linspace(0 8 *π,《不扩散核武器条约》);z = linspace(-1,1,npts); omz = sqrt(1-z.^2); xyz = [cos(t).*omz; sin(t).*omz; z]; plot3(xyz(1,:),xyz(2,:),xyz(3,:),'ro','LineWidth',2); text(xyz(1,:),xyz(2,:),xyz(3,:),[repmat(' ',npts,1), num2str((1:npts)')]) ax = gca; ax.XTick = []; ax.YTick = []; ax.ZTick = []; boxon

Connecting the Points

Here is the 3D spline curve through these points provided bycscvn. By appending the first point to the end of the list, we get a smoothclosedcurve.

holdonfnplt(cscvn(xyz(:,[1:end 1])),'r',2) holdoff