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Keep up to date with Steve Nurse's designs and 3d printing.

Monday 17 September 2018


Three pics of

the cuboctahedron from

Geodesic math and how to use it by Hugh Kenner.
Struts laid out, then

transfered to acs10 matting.

End result with tools etc.


Hi, Last time in this series, I built a six strut tensegrity, and this time I am building the next structure in Mr. Kenner's book, the cuboctahedron.  If you think its getting complicated you are right, if you think pic 3 above shows a mish mash of units which is a mathematical blasphemy you are right.  But I am plodding on with these things.

To start with I got my 3d printer going, made 24 of the orange rod ends, then stuck them on to some sawn-off pieces of fibreglass tent pole.  The fit wasn't quite right, so I bulked out the rod ends with sticky tape, and hey presto, a nice fit, and 12 struts are ready. Finished making the struts last night.

Next, replacing tendons with rubber bands, I lay out the struts minus the top and bottom rows of rubber bands, which would cause it all to collapse (pic 4).   To complete the assembly I tried rolling that lot around a bucket which failed causing rubber bands to fall off.

After a bit of thought I tried a different approach and laid everything out on Ventisit or ACS10 which  is a mesh material I use to cover recumbent bike seats.  Then the struts were cable tied to the mesh, and the mesh rolled around in a circle, extra linking rubber bands linked up, cable ties removed, and finally, the acs10 rolled up a bit tighter and removed.  Hey presto, all done!

But still confusing!  Not sure how what I've built relates to a cuboctahedron, but I will investigate. And from pics 3 and 4 it looks like the pattern could be changed with 3 or 5 or 6 sets of 3 struts.

Next step in Kenner's book is icosidodecahedron which both looks and sounds fiendish.


Steve Nurse

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