axial creases

Sadarac · Post by **Sadarac** » November 29th, 2008, 5:40 pm

I have robert langs "ODS" and i have read chapters 1-10. But i still dont completely understand how to find axial creases for a base. Could sobody explain this in more simple terms? thanks!

Jonnycakes · Post by **Jonnycakes** » November 29th, 2008, 6:28 pm

Axial creases are the lines that go along the length of the flap. If you are designing with circle-packing, simply draw lines between the centers of circles that touch each other (and that touch the same river at the same spot). For box-pleating, the axial creases will always go vertically and horizontally from the center of the flap. If this does not make sense, I will be happy to further clarify it.

Sadarac · Post by **Sadarac** » November 29th, 2008, 6:35 pm

The rivers and boxpletes still sorta throw me.

Zoraz · Post by **Zoraz** » November 30th, 2008, 2:51 am

Rivers confused me for a while too, but they are pretty simple. I will attempt to explain.
Circles in the pattern correspond to flaps on the base, and the longer flaps have bigger circles. in the same way, rivers are the spaces between flaps, and the wider the river is, the farther away the two flaps are. For example, on the cockroach pattern on page 363, the rivers make up the area between the legs.
When folding a base with rivers....just ignore them! The model will still work out just fine, and you will see how they work in the base.

As for boxpleating, i would highly recommend Daydreamer's blog. I think he advertised it in the personal section. It helped me start off boxpleating.

Jonnycakes · Post by **Jonnycakes** » November 30th, 2008, 4:02 am

In normal circle-packing, axial creases only go through rivers where there is a circle touching on either side of it. If there is a circle touching the river on one side only, an axial crease doesn't run through it there.

Box pleating is a little more tricky-axial creases must connect to another crease of the same polarity. That crease doesn't have to connect to the center of another circle-it could reflect across a diagonal or run into the edge of the paper.

Is it the conceptualization of axial creases or how they play into the rest of the crease pattern or something else entirely that you are having trouble with?

Sadarac · Post by **Sadarac** » November 30th, 2008, 7:31 am

i think i get it now. now i just need to make the jig and figuer out a circle packing for a design

Jonnycakes · Post by **Jonnycakes** » November 30th, 2008, 6:46 pm

You don't need a jig for that. I don't think it is necessary or worth it to build one. Just use a pencil and paper to sketch out a rough circle packing design (this way you can add rivers, too). You need to do some geometry to figure out the lengths and proportions of everything (and that can be difficult at times), but then you can just plug some points into Referencefinder.

Sadarac · Post by **Sadarac** » November 30th, 2008, 11:25 pm

maybe for you. But i suck at trying to draw shapes freehand

i can draw animals and figuers and such okay. but not shapes:( thats why i make a jig

Jonnycakes · Post by **Jonnycakes** » December 1st, 2008, 3:15 am

Fair enough. For me as well my drawings are often off from the actual mathematically correct version. Now I use gridded paper to sketch CPs and circle packings-it helps a lot.

Sadarac · Post by **Sadarac** » December 1st, 2008, 3:36 am

good idea! (now i can design when i dont have a jig:) )

Post by **origami_8** » December 1st, 2008, 9:30 am

Speaking of gridded paper, with this free little program you can make all kinds of graph papers yourself (e.g. thin lines every 2mm and thick lines every 8mm, or triangular grids,...): http://pharm.kuleuven.be/pharbio/gpaper.htm

Jonnycakes · Post by **Jonnycakes** » December 1st, 2008, 6:34 pm

That program is fantastic-finally I don't have to do triangular grids on square gridded paper!

qtrollip · Post by **qtrollip** » December 1st, 2008, 8:05 pm

Grids and the ability to change their scale is standard with any Cad program, which includes the drawing tools needed, accurate to 1000s of a millimeter.
To me still a perfect origami program - the only problem is compatibility with other programs.

Jonnycakes, I dont know about triangular grids though, that is pretty awesome about this linked program. But there is a way around that with Cad as well.

Post by **origami_8** » December 1st, 2008, 8:23 pm

I agree that drawing on a computer is more accurate, but drawing by hand is much faster. For most of my computer diagrams I draw hand sketches first and for drawing these scatches a gridded paper can sometimes help a lot.
The good thing on this program is that you just give a few commands and can print your paper and don't need to construct it first.

Sadarac · Post by **Sadarac** » December 2nd, 2008, 3:43 am

cool! ill have to look at it later.