The Origami Forum

there are certain models that sometimes calls for flaps/columns/rows to be divided into thirds. i am just curious as to what folders here prefer to do. good examples include the kawahata stegosaurus, which has rows which have to be divided into thirds, and kamiya's ancient dragon, where the precreasing for the claws involve dividing flaps into thirds.

as i get older i find that i just go straight to a ruler. sometimes, if the area is well-defined enough, and i can't get an exact number (i.e., sometimes you get 41mm flaps or 44 mm flaps), i will find a square that fits the column and divide using methods which are thoroughly outlined in other places for dividing squares into odd numbers, using these as a reference. i guess another way would be to "eyeball" it, but that's too inexact and trying for me.

I always eyeball thirds and fifths and am always very accurate. Sometimes I tried measuring but always ended up more inaccurate than I ever did with eyeballing.

The haga theorems give mathematically accurate proportions. you can use them to get thirds and fifths rather easily and precisely just by folding.

I don't know, to fold a flap inside the model that is maybe triangular regarding to the Haga theorems sounds a little bit odd to me, there's too much mathematics involved. I stick to my guesswork.

The Haga theorum works very well for dividing the beginning square into fractions, but has limited applications otherwise. For dividing a flap into thirds, it is fine to eyeball it.

Oops, I thought you were only referring to the beginning square. I have not encountered to many models that require you to divide flaps into thirds, except Lang Praying Mantis and Scorpion.

There are some flaps where 1/2 thickness is still too wide and 1/4 thickness is too skinny, so you must divide them into 1/3rds instead. Peter Engel's Octopus is another model that does this (quite extensively, at that).

I'm no expert, but I'm going to guess that a reasonable approximation will give you a solid result with less aspirin involved.