A very useful tool

Drafting A Circle Pattern

Better brush off those old math textbooks...

The whole purpose of drafting circles comes in real handy for making skirts and cloaks. Oh, sure, you can gather a gigantic rectangle of fabric into a waistband, but do you really want all that bulk around your hips? Do the same thing to a collar, and you've got what amounts to a Kinsale cloak, but I can fit me and five of my friends under my half-circle cloak. Never could make that happen under a Kinsale.

So, because I've thought about publishing this for a long time and someone finally asked me, here's the process I use for drafting a circle pattern. We're doing a cloak in this example, but substitute "waist" every time you see "neck", and everything else is the same.

The steps for making a circle cloak - or any fraction thereof - are pretty simple, but you're going to have to reach back to high-school geometry. It all revolves around one equation:

C = 2πR

In other words:

Circumference = 2 * 3.14 * R
(neck size) (which will be the radius of the circle we'll be drafting)
Now, no matter what fraction of a circle you want to make, it works easiest if you're always working with a full circle for the equation. So:

Size                     Multiplier
Full Circle Neck size (as is)
Half Circle Neck Size * 2
3/4 Circle (Neck Size / 3) * 4

So, for a half circle cloak with a neckline of, say, 20", we get this:

  1. 20 * 2 = 40 (or C)
  2. Subsitute that into the equation: 40 = 2πR
  3. 40 = 6.28R (calculate 2 * π)
  4. R = 40/6.28 (calculate the radius by dividing 6.28 by 40)*
  5. R = 6.37
* after all this time, I usually just mentally skip to step 4.

For convenience, and because it's easier to take something in than let it out, we'll round up to the nearest quarter and call it 6.5". (Always round up to the nearest quarter.)

That's pretty much all the math we'll need for now. On to step 2.


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