# File:Torus illustration.png

Original file(900 × 594 pixels, file size: 147 KB, MIME type: image/png)

This diagram was created with MATLAB.

 Description Illustration of torus Date 13 July 2008, 01:12 (UTC) Source self-made, with MATLAB Author Oleg Alexandrov Other versions Derivative works of this file:  Infobox torus.png
 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.

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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 = (-Kb-h):h:(Kb+h);   m = length(X);
Y = (-Kb-h):h:(Kb+h);   n = length(Y);
Z = (-r-h):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.^2-r^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'));
```

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## File history

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Date/TimeThumbnailDimensionsUserComment
current01:12, 13 July 2008900 × 594 (147 KB)Oleg Alexandrov{{Information |Description=Illustration of torus |Source=self-made, with MATLAB |Date=~~~~~ |Author= Oleg Alexandrov }} {{PD-self}} ==Source code== <source lang="matlab"> % illustration of a torus, o
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