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This chart was created with MATLAB. 
Description 
Illustration of torus 
Date 
01:12, 13 July 2008 (UTC) 
Source 
selfmade, with MATLAB 
Author 
Oleg Alexandrov 
Public domainPublic domainfalsefalse 

I, the copyright holder of this work, release this work into the public domain. This applies worldwide. In some countries this may not be legally possible; if so: I grant anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law.Public domainPublic domainfalsefalse


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Source code
% illustration of a torus, obtained as an isosurface
function main()
% big and small radii of the torus
R = 3; r = 1;
Kb = R+r;
h = 0.1; % h is the grid size. Smaller h means prettier picture.
X = (Kbh):h:(Kb+h); m = length(X);
Y = (Kbh):h:(Kb+h); n = length(Y);
Z = (rh):h:(r+h); k = length(Z);
W = zeros(m, n, k); % the zero level set of this function will be the desired shape
for i=1:m
for j=1:n
x = X(i);
y = Y(j);
W(i, j, :) = (sqrt(x^2+y^2)R)^2 + Z.^2r^2; % torus eqn, vectorize in Z
end
end
figure(4); clf; hold on; axis equal; axis off;
H = patch(isosurface(W, 0));
isonormals(W, H);
light_green=[184, 224, 98]/256;
% set some propeties
set(H, 'FaceColor', light_green, 'EdgeColor','none', 'FaceAlpha', 1);
set(H, 'SpecularColorReflectance', 0.1, 'DiffuseStrength', 0.8);
set(H, 'FaceLighting', 'phong', 'AmbientStrength', 0.3);
set(H, 'SpecularExponent', 108);
daspect([1 1 1]);
axis tight;
colormap(prism(28))
% viewing angle
view(146, 32);
% add in a source of light
camlight (10, 54); lighting phong;
%save as png
print('dpng', 'r400', sprintf('Torus_illustration.png'));
File usage
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