sphere made of 2d circles in 3d plot

Question

reza 2014-1-2

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链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/111233-sphere-made-of-2d-circles-in-3d-plot

编辑： Roger Stafford 2014-1-2

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);

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Walter Roberson 2014-1-2

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

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Answer 1

Amit 2014-1-2

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/111233-sphere-made-of-2d-circles-in-3d-plot#answer_119873

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

2 个评论
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Amit 2014-1-2

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

Amit 2014-1-2

在 MATLAB Online 中打开

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

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Answer 2

Roger Stafford 2014-1-2

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/111233-sphere-made-of-2d-circles-in-3d-plot#answer_119876

编辑：Roger Stafford 2014-1-2

在 MATLAB Online 中打开

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