plot spheres in 3D with one color (no gradient)

Hi everyone

I want to plot spheres in 3 D with one color (no gradient). I used surf function as shown below, where a is radius, XT,YT,ZT are the center position in x,y,z and N is number of spheres.

 for k=1:1:1%size(XT,1)

        for j=1:N

            % Generate a sphere consisting of 20by 20 faces
            [x,y,z]=sphere;
            % use surf function to plot
            hSurface=surf(a*x+XT(k,j),a*y+YT(k,j),a*z+ZT(k,j));  hold on
            set(hSurface,'FaceColor',[0 0 1], 'FaceAlpha',0.5,'EdgeAlpha', 0);
            axis([-0.5 0.5 -0.5 0.5 -0.5 0.5]);
            daspect([1 1 1]);
            W(k)=getframe(gcf);

        end 
            hold off

            xlabel('X')
            ylabel('Y')
            zlabel('Z')
    end

    movie2avi(W,'35_percent.avi');

Without using 'EdgeAlpha', the spheres look right in 3D but it is visible the point to point edges due to surf function. However, if I include 'EdgeAlpha' to make invisible point to point edges, but the spheres are now in Circle (2D).

How do I plot spheres in 3D and in one color without seeing the point-point edges of plotted surface.

Thanks

Answer 1

[Mike Garrity]

A solid FaceColor alone isn't going to give you any feeling of the 3D shape of the spheres. If you take the edges away, you'll need to use something else to show the shape.

One option is lighting:

N = 15;
a = 1/8;
XT = randn(1,N)/6;
YT = randn(1,N)/6;
ZT = randn(1,N)/6;
for j=1:N
  % Generate a sphere consisting of 20by 20 faces
  [x,y,z]=sphere;
  % use surf function to plot
  hSurface=surf(a*x+XT(j),a*y+YT(j),a*z+ZT(j));
  hold on
  set(hSurface,'FaceColor',[0 0 1], ...
      'FaceAlpha',0.5,'FaceLighting','gouraud','EdgeColor','none')
  axis([-0.5 0.5 -0.5 0.5 -0.5 0.5]);
  daspect([1 1 1]);
end
hold off
xlabel('X')
ylabel('Y')
zlabel('Z')
camlight

Another option would be to use FaceColor to shade them:

N = 15;
a = 1/8;
 XT = randn(1,N)/6;
YT = randn(1,N)/6;
ZT = randn(1,N)/6;
[x,y,z]=sphere;
l = [.25 -.433 .5];
c = max(0,x*l(1) + y*l(2) + z*l(3));
for j=1:N
  % use surf function to plot
  hSurface=surf(a*x+XT(j),a*y+YT(j),a*z+ZT(j),c);
  hold on
  set(hSurface,'FaceColor','interp','FaceAlpha',0.5,'EdgeColor','none')
  axis([-0.5 0.5 -0.5 0.5 -0.5 0.5]);
  daspect([1 1 1]);
end
hold off
xlabel('X')
ylabel('Y')
zlabel('Z')
colormap hot