Plotting irregular volume of given vertices.

I am using convhull for plotting 3D irregular volume for a given set of vertices(more than 10). But the resulting volume consist of lines connecting between all vertices as shown in the figure.

Is there any method to plot only the faces and avoid the lines passing through the volume?

if true
  % code
x=pts1(:,1);y=pts1(:,2);z=pts1(:,3);
k = convhull(x,y,z);
plot3(x(k),y(k),z(k),'r-')

end

Thanks Shyam

Answer 1

[David Goodmanson]

Hi syham,

Here is an example using patch.

n = 6;
x = rand(1,n);
y = rand(1,n);
z = rand(1,n);

k = convhull(x,y,z)';
colorr = [.7 .2 .3];
close          % temporary expedient for situation mentioned below                                
figure(1)
patch(x(k),y(k),z(k),colorr);     
alpha(.2)                                % transparancy

Unlike e.g. the plot command, the patch command seems to put the figure into a permanent 'hold on' state so that another patch command adds to what is already there. Not a big deal, but I don't know how to plot a new convex hull without closing the figure first or adding another figure.

[John D'Errico]

Trimesh is a simple alternative. It shouldn't leave the graphic on hold either.

xyz = randn(100,3);
tri = convhulln(xyz);
trimesh(tri,xyz(:,1),xyz(:,2),xyz(:,3),'facecolor','r','facealpha',.3,'edgecolor','k')