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Battle of the sonobe units and menger sponges Rhugha
Please take a seat and listen to my thoughts on this subject, or just skip the thread if you're not interested in modular origami. =)

>Sonobe problem

The first modular unit I ever folded was the original sonobe unit (op pic), and ever since I used it for every cube and whatever else is to be assembled with them.And huge ones at that. Sometimes a slight variation, but nothing big.


So yesterday I was looking through Tomoko Fusès book 'Unit Origami' and discovered a, to me, totally new variation which doesn't contain the typical "tucking in" flaps.
http://img412.imageshack.us/img412/6421/tsunitna1.png


Since this unit was against my sonobe-belief, I folded 6 pieces to assemble a cube and the results were pretty good I must admit.


My question resulting from my experience now is:
Which one do you favor, and why?

Both are easy to fold, Tomoko's maybe even a little faster.And both seem pretty sturdy as well, for the cube that is.

Anyone knows which would be superior for large models in the 90~300 units range from experience?


I'll need 3 posts for this..
>> Rhugha
>Menger sponge problem

After the clash of the sonobe units, I soon found the next disturbing thing.
The menger sponge made of sonobe units.
http://bilder.chsemrau.de/origami/P7294389_klein.jpg
I made a level 1 and 1/4 of a level 2 sponge of original units which should look like this when completed
http://www.ganymeta.org/~darren/images/origami/gallery/mengersponge.jpg
2400 units, yay.


But then I ran across a different version of the menger sponge, made of significantly less units.
http://www.origami.friko.pl/sonobe/sonobe/11.jpg
As I write, I am folding the required number of units to complete one.

The main difference would be that the sponge is totally hollow (not the 'missing' parts, the actualy sponge) as opposed to the version I am folding, where a cube is folded and then a mirrored cube is connected to it.

The larger the sponge, the bigger the difference in the number of parts. A level 2 menger sponge made of version 2
http://www.origami.friko.pl/sonobe/sonobe/12.jpg
Only needs 1056 modules opposed to 2400! modules.
Now imagine a level 3..
>> Rhugha
So my question here:
Which is the 'better' way (I know there is better way, I just don't know what else to ask) to assemble larger sponges?
Version 2 definately has the low unit cost advantage and it looks 'smoother' than version 1, but is it as stable as version 1?
Here a Level 3-in progress, version 2
http://www.origami.friko.pl/sonobe/sonobe/15.jpg
Looks pretty good to me.

And this bring me back to the sonobe problem:
Which unit for which sponge?

Sorry if I wrote to much, but sometimes little things like this can bug me a lot. Lol.

And here's the TL;DR

>Sonobe unit, 1 or 2?
1)OP Pic
2)http://img412.imageshack.us/img412/6421/tsunitna1.png

> Menger Sponge, 1 or 2? (assembly technique differs)
1)http://www.ganymeta.org/~darren/images/origami/gallery/mengersponge.jpg
2)http://www.origami.friko.pl/sonobe/sonobe/12.jpg

Thanks for your time and reading.
Hoping for at least some responses =)
>> Anonymous
Truly a record length thread by the OP alone.

As for the Menger Sponge, the best one might be... business cards?

http://www.theiff.org/oexhibits/menger02.html
http://www.msstate.edu/web/phototemplate.php?Id=1737

Perhaps there won't be much difference between the two sonobe modules. The thing to watch is that a level 3 sponge is pretty heavy on the lower modules; a level 4 sponge might be impossible with standard weigh paper modules. (it is considered impossible with business cards, as shown above).

There are many other variations of the sonobe module... was that the only one in that book that caught your attention?
>> Rhugha
I left out business cards cube for a good (for me at least) reason, which is money.

As you can see here, you'd need 192 cards for a level 1.Level 2 would take 3456 already, 66,048 business cards for a level 3 according to this site.
http://world.std.com/~j9/sponge/

I looked up some prices:
400 white blank business cards 12,60€
700 white square sheets, post it like..w/e lol, cheapest is 2,61€
700 colored square sheets, 3,61€

>Level 2 menger sponge:
Business cards ~ 3456 units ~ 110€
Sonobe Version 1 ~ 2400 units ~ 9€ - 12€
Sonobe Version 2 ~ 1056 units ~ 4€ - 6€
You see where this is going I guess.

Pro square sheets:
Cheap as hell -> Can be bought in huge numbers to assure the same brand is available

Con square sheets:
Not always exactly square which can be a pain. Though, sonobe units are forgiving.


Pro business cards:
-Same brand = exact the same size for every card I guess.
-VERY easy folding of the units, lol.

Con business cards:
Money..


So after all, I'd prefer to go with sonobe units.
I didn't finish my level 2 yet, so I won't dream of level 4.This won't be a problem for some time.


As for the sonobe variations:
I know there's loads, about 9 in the 'Modular Origami Polyhedra' book for example, but this very one caught my attention cause it doesn't 'tuck' the flaps into the front but fold it to the back.I've never seen that technique before.

To be honest, I don't know if there are more variations in the 'Unit Origami' book, as it's like 240 sites, and this unit is on page 7x. I didn't read through the whole book yet.