File Exchange

## Sierpinski ball

version 3.3 (146 KB) by
Function to compute, display, and save the Sierpinski ball (fractal sponge) based on the regular octahedron

Updated 03 Sep 2020

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Please first check the examples tab (doc) here on the right for a complete description.

Once downloaded, typewrite 'doc Sierpinski_ball' or 'help Sierpinski_ball' in Matlab console for support.

N.B. : level 0 corresponds to the volumic mesh of the unit ball (radius = 1).

### Cite As

Nicolas Douillet (2020). Sierpinski ball (https://www.mathworks.com/matlabcentral/fileexchange/73432-sierpinski-ball), MATLAB Central File Exchange. Retrieved .

Nicolas Douillet

Color rendering used for this cover image is radius based, i.e. by computing each vertex distance to the origin : C = sqrt(sum(V.^2,2)); trisurf(T,V(:,1),V(:,2),V(:,3),C); colormap('jet');

Nicolas Douillet

Default maximum number of iterations and sampling steps (nb_max_it) set to 7. Increase it line 84.

Nicolas Douillet

A function to compute a Sierpinski ball. Giving the resulting sets of vertices and triangles, it is almost 3D printing ready. Just have to write them in a .ply file for instance. The fractal object thereby created is a fractal sponge.

The algorithm principle is based on the projection of the Sierpinski triangular faces of a regular octahedron on the surface of the unitary sphere.

It is available for 3D printing in my Sculpteo online shop at iteration #3 :

NB : function sample_triangle isincluded, but may also be found independently here :

https://fr.mathworks.com/matlabcentral/fileexchange/64395-sample_triangle?s_tid=prof_contriblnk

You may also have a look at some additional views here :

https://www.flickr.com/photos/153363591@N05/albums/72157689739929586

Tip : from nb_iterations = 3, and if using write_ply.m you struggle with displaying the set out of Matlab [...] try to replace in the file header "uchar ushort" by "uint8 uint32" this may help ;-)

##### MATLAB Release Compatibility
Created with R2019b
Compatible with any release
##### Platform Compatibility
Windows macOS Linux