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Rhombitruncated icosidodecahedron

PostPosted: Thu Jan 07, 2010 1:28 pm
by Tychi
I built rhombitruncated icosidodecahedron, but it fell.
Image
And so I have one question for you: What should be its base .. square, hexagon or decagon?

Tychi
http://jihprotiseveru.blogspot.com/search?updated-min=2010-01-01T00%3A00%3A00%2B01%3A00&updated-max=2011-01-01T00%3A00%3A00%2B01%3A00&max-results=3

Re: Rhombitruncated icosidodecahedron

PostPosted: Thu Jan 07, 2010 3:03 pm
by Peter Jepsen
I would say decagon. But then I noticed that you built it in a different way than I've always done.

DSC_5709_resize.jpg

This version is more reinforced and very stable when it's complete. On this photo it is resting on a square, but my guess is that the decagon is still best.

I found the numbers for the version on the photo:
600 rods
260 spheres
140 Triangles
60 Squares
72 Pentagons
60 Diamonds

Re: Rhombitruncated icosidodecahedron

PostPosted: Thu Jan 07, 2010 4:02 pm
by Tychi
I have a few rods ;)
I found this construction on the Rafaels web..here http://textodigital.com/P/GG/bpoli.php#p1220rt

Re: Rhombitruncated icosidodecahedron

PostPosted: Thu Jan 07, 2010 5:28 pm
by Peter Jepsen
Also Rafael's is resting on the dodecagon face.

For reference, the one on my photo is built around a rhombicosidodecahedron, meaning that first you build the rhombicosidodecahedron and then you build the rhombitruncated icosidodecahedron on the outside of it. You can see the structure of the rhombicosidodecahedron through the open holes.

Rhombitruncated-Icosidodeca.png

I don't know if this version/construction variation has a different name than the one you found on Rafael's site. The outside shape is the same. The first model of this that I saw had been built by Michele Grisoni of the Geomag company.

Re: Rhombitruncated icosidodecahedron

PostPosted: Sat Jan 09, 2010 9:37 am
by Tychi
so I'll try it again. Thank you for your answer.

Re: Rhombitruncated icosidodecahedron

PostPosted: Sat Jan 09, 2010 10:02 am
by karlhorton
Peter,

the (excellent) picture you showed seems to be rendered from a model, rather
than being a photograph of a real world object.

Is that so? If so, can you let us use the software?

Or is it in-house Geomag only?

regards, Karl

Re: Rhombitruncated icosidodecahedron

PostPosted: Sat Jan 09, 2010 10:08 am
by karlhorton
Tychi,

are you aware of the need to "balance" all of your joints when
building large fragile models like this?

I see here that most of the balls have four rods, which means
that they can be set up with two north poles and two south poles: joints
like this are much stronger.

The centers of the hexagons are unbalanced, however you can secretly
balance them by adding a dangling 4th rod to the interior of the model.

I've balanced an icosahedron successfully using that technique - never actually
built this model.

regards, Karl

Re: Rhombitruncated icosidodecahedron

PostPosted: Sat Jan 09, 2010 6:19 pm
by Tychi
Karl, there are also balls with five rods.

It fell de facto, when I turned with it, which I probably should not do ;)

Re: Rhombitruncated icosidodecahedron

PostPosted: Tue Jan 12, 2010 12:25 pm
by Peter Jepsen
Regarding the software, "Geomag CAD" if you will.
It's a proprietary software which is in unstable Beta state and neither available nor ready for public use.
The project was halted and ended up in limbo and at the moment there are no definitive plans to continue development.
I'd personally like the software to be finished but it's a low priority for the company, the focus being on the KIDS and Gbaby lines at the moment (Mainly as a result of what seems to now have been dubbed the "Magnetix scare").

Re: Rhombitruncated icosidodecahedron

PostPosted: Tue Jan 12, 2010 12:36 pm
by AFKAN
That's a shame Peter :(

Looks like an awesome piece of software 8-)