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### Corrugation?

Posted: November 20th, 2018, 6:16 am
I read here a definition of an origami corrugation, as opposed to a classic tessellation, but I didn't really get it. Can you please help me understand what it is?

https://origami.me/tessellations/

### Re: Corrugation?

Posted: November 20th, 2018, 10:21 am
I don't think it is as clear cut a definition as the author would like, but the basic premise is the number of stacked layers in the paper. If you hold it up to the light and no new layers are visible it's a corrugation. If a different or more expansive pattern emerges it's a tesselation.

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### Re: Corrugation?

Posted: November 20th, 2018, 3:03 pm
Grace159 wrote:I don't think it is as clear cut a definition as the author would like, but the basic premise is the number of stacked layers in the paper. If you hold it up to the light and no new layers are visible it's a corrugation. If a different or more expansive pattern emerges it's a tesselation.

I've seen this definition before and this over simplification of what a corrugation is leads to a lot of errors and people considering basic pureland folds as corrugations when they clearly aren't.

Merian Webester Dictionary defines corrugating as "to form or shape into wrinkles or folds or into alternating ridges and grooves", the key word here is alternating, that's what defines a corrugation despite if you see one or more layers when held up to the light.

I'll take advantage of this question to promote the Flickr Origami Corrugation Group that you can check at: https://www.flickr.com/groups/corrugation/

### Re: Corrugation?

Posted: November 20th, 2018, 8:57 pm
Here's my personal definition (others are welcome to add or subtract):
1) the pattern must tessellate BUT
2) the creases are left open (meaning they're not folded flat) AND
3) flattening the pattern results in a different-looking shape

### Re: Corrugation?

Posted: November 21st, 2018, 7:40 pm
Thank you guys; I think I understand a bit more now. The article I linked shows the following two folds and declares they are tessellations. Aren't they really corrugations?

Heptamerous ver 3, Designed and Folded by Ilan Garibi

Mystery, Designed and Folded by Ilan Garibi

If I'm wrong can you please explain why?

### Re: Corrugation?

Posted: November 22nd, 2018, 1:39 am
There are no "alternating ridges and grooves" hence they are not corrugations.

A note on this, a tessellation is the repetition of a pattern to fill b the plane, so a corrugation can also be a tessellation.

### Re: Corrugation?

Posted: November 23rd, 2018, 7:31 pm
Oh, the "alternating ridges and grooves" is what lets you "see the entire surface of the paper". That would avoid the accumulation of layers. Am I right?

### Re: Corrugation?

Posted: November 24th, 2018, 12:57 am
I'm not sure about the accumulation of paper thing since I've never attached to that definition.

Basically a corrugation is something similar to this:
https://www.flickr.com/photos/georigami/144377615/

Sorry I can't link directly to the photo but I'm on my phone and don't know how to do it.

### Re: Corrugation?

Posted: November 25th, 2018, 11:35 pm
Here are some counter examples to the "hold up to the light" nonsense:

And another one which is not allowing me to directly link to it:
http://www.flickr.com/photos/95620469@N02/45996525882/

### Re: Corrugation?

Posted: November 26th, 2018, 12:37 am
WOA! Those are also corrugations?!