Lang - Design Secrets - Chapter 12

cjbnc · Post by **cjbnc** » February 1st, 2011, 8:27 pm

I was re-reading the chapter on box pleating, and figured I'd try to fold some of his example CPs. I discovered that, at least by my printing, the beetle in figures 12.46 and 12.48 does not appear to be flat-foldable. The central abdominal point has 8 creases, 4M and 4V. The two points on either side have 4 creases each, all the same parity.

I've tried working through his derivation, but I can't figure out how to set the folds to make this CP work. Has anyone managed it that they could share a working CP with me, or point me in the right direction to solve it?

Thanks

FlareglooM · Post by **FlareglooM** » February 1st, 2011, 8:56 pm

For 12.46, ignore the complete horizontal fold at 1/3 (from below). This is the one with brown-black-black-brown. As far as I see it, this should fix it completely. Also the thin black lines are help lines to get to the base afaik, but aren't in the base.

For 12.48 it is basically the same as in 12.46 noted above.

cjbnc · Post by **cjbnc** » February 1st, 2011, 9:50 pm

Thank you FlareglooM - that was the trick. I realized the thin lines were hinge creases, but I hadn't realized it was correct to change a fold to a hinge instead of just changing its parity. I followed your suggestion and the base folds pretty easily now.

HankSimon · Post by **HankSimon** » February 2nd, 2011, 6:19 pm

How about Mooser's Train ?

- Hank Simon

FrumiousBandersnatch · February 2nd, 2011, 6:45 pm

What about it, Hank?

merman · Post by **merman** » February 3rd, 2011, 9:14 am

A sequel/revised edition of the book wil be published soon. I think April

HankSimon · Post by **HankSimon** » February 3rd, 2011, 6:40 pm

Since cjbnc is working on Box pleating, I was suggesting Mooser's Train... of course, considering the other CPs that folks have done, I guess that Mooser's train is now considered a fairly simple example...

- Hank Simon

cjbnc · Post by **cjbnc** » February 3rd, 2011, 8:32 pm

Haven't tried it yet. Perhaps tonight.

I was re-reading the chapter and doing that particular example so I could better understand the process of creating the CP. With a little trial and error I managed to make a base of my own from a tree graph and folded it... progress!

HopefulFolds · Post by **HopefulFolds** » February 4th, 2011, 3:52 am

I had trouble with this when I first started CPs.

Whenever there are 4 lines intersecting, you MUST remove one in order to make it flat foldable. Sometimes CPs don't show this - you have to do it yourself.

ahudson · Post by **ahudson** » February 4th, 2011, 4:43 am

HopefulFolds wrote:I had trouble with this when I first started CPs.

Whenever there are 4 lines intersecting, you MUST remove one in order to make it flat foldable. Sometimes CPs don't show this - you have to do it yourself.

Not actually true. A waterbomb base folded in half has four lines intersecting, and in fact any arrangement with mirror symmetry across two of the four lines will be flat-foldable, although the crease assignment will not be mirror-symmetric.

Creasepatterns 12.46 and 12.48 should be foldable if you reassign parts of that horizontal fold to mountain creases. They won't look like the folded form shown in the book, but they'll work.

Post by **origami_8** » February 11th, 2011, 3:04 pm

Actually you do have to remove one of the four intersecting creases of the waterbomb base to make it flat foldable. Using all four creases it would always remain 3-dimensional. In other words, you only use three of the four creases.

gachepapier · Post by **gachepapier** » February 11th, 2011, 4:40 pm

origami_8 wrote:Actually you do have to remove one of the four intersecting creases of the waterbomb base to make it flat foldable. Using all four creases it would always remain 3-dimensional. In other words, you only use three of the four creases.

Nope - you can fold along all 4 lines and have a flat base - you'll get a point with a 45° opening. Just fold the shape you reach after collapsing three lines along the fourth... (along the remaining axis of symetry)

Not that you'd want to in most cases though

Post by **origami_8** » February 11th, 2011, 5:09 pm

Yes, but that would change the Crease direction of one half of a fold no longer leading to a waterbomb base. This base would be having three valley and five mountain folds on the inside CP. Whereas on a waterbomb base you have two mountain and four valley folds on the inside CP that are being used.

Lithium · Post by **Lithium** » February 15th, 2011, 10:44 pm

gachepapier wrote:
origami_8 wrote:Actually you do have to remove one of the four intersecting creases of the waterbomb base to make it flat foldable. Using all four creases it would always remain 3-dimensional. In other words, you only use three of the four creases.
Nope - you can fold along all 4 lines and have a flat base - you'll get a point with a 45° opening. Just fold the shape you reach after collapsing three lines along the fourth... (along the remaining axis of symetry)

Not that you'd want to in most cases though

Lang's Fiddler Crab does that, at the vertex down by the tip of the biggest claw. Took me forever to figure out how to collapse that stupid thing...