sphere made of 2d circles in 3d plot

hi i made the code below the create a sphere using 2d circles in a 3d plot:

r=1

teta=-pi:0.01:pi

x=r*cos(teta);

y=r*sin(teta);

axis square

for i=0.0:0.1:1

      z=i*sin(teta);

      plot3(x,y,z);    

      hold on

end

for i=0.0:-0.1:-1

      z=i*sin(teta);

      plot3(x,y,z);

      hold on

end

for i=0.0:0.1:1

      y=i*sin(teta);

      plot3(x,y,z);

      hold on

end

for i=0.0:-0.1:-1

      y=i*sin(teta);

      plot3(x,y,z);

      hold on

end

however it doesn't create a clear sphere from some views it shows sphere from some views it shows something( i don't know what ).

anyway i want to creat a sphere using the code below to create a sphere using 2d circles(code below).

r=1

teta=-pi:0.01:pi

x=r*cos(teta);

y=r*sin(teta);

z=zeros(1,numel(x));

plot3(x,y,z);

[Walter Roberson]

This should probably have been a continuation of http://www.mathworks.co.uk/matlabcentral/answers/111219-3d-plot-2d-cirlce-specific-degree-tilt-slope

Answer 1

[Amit]

You can use sphere function to create a sphere. Do you specifically need sphere from circles?

[Amit]

Moreover, the equation you have used does not represent a sphere.

[Amit]

If you really just want to use 2-D circles, the code will be something like this:

r=1;
teta=-pi:0.1:pi;
x=zeros(size(teta));
y=x;
z = x;
axis square

for i=(-1)*r:0.1:r
    x = ((r^2-i^2)^0.5)*cos(teta);
    y = ((r^2-i^2)^0.5)*sin(teta);
    z = i*ones(size(teta));
    plot3(x,y,z);
    hold on;
end

Answer 2

[Roger Stafford]

To use 'surf' do this:

 r = 1;
 [theta,phi] = ndgrid(linspace(0,pi),linspace(0,2*pi));
 X = r*cos(phi).*sin(theta);
 Y = r*sin(phi).*sin(theta);
 Z = r*cos(theta);
 surf(X,Y,Z)

or if you just want circles, do this:

 r = 1;
 [theta,phi] = ndgrid(linspace(0,pi),linspace(0,2*pi));
 X = r*cos(phi).*sin(theta);
 Y = r*sin(phi).*sin(theta);
 Z = r*cos(theta);
 for k = 1:numel(theta)
  plot3(X(k,:),Y(k,:),Z(k,:))
  hold on
 end

(Corrected)