Our techniques series looks at some of the many different tricks and methods used in designing zero-waste patterns. Useful and interesting for pattern designers and home sewers alike!
You can think of most garments as a series of tubes: a shirt is a larger tube for the body and two smaller tubes or the arms; pants are two tubes joined at the crotch, etc. So what are some different ways to create tubes?
1. simple tube
The basic tube is of course just a rectangle curved together. A tall, narrow rectangle will predictably produce a tall, narrow tube; a short fat rectangle will produce a short fat tube.
Examples: not too many garments are made from a single straight tube with no modifications. A knit pencil skirt might be one. There are some tops which are made from three tubes (one big one for the body and two small ones for the sleeves), such as the Slash Neck Zero Waste Tee.
2. tapered tube
Since most of our body parts aren’t straight up and down, it’s also useful to be able to make tapered tubes – tubes where one end is bigger than the other (if you remember any of your basic geometry lessons, this is called a truncated cone).
Again, the dimensions of the arc you start with affect the finished tube.
And since often we want to deal with straight lines, we can make the arc shape from a series of wedges. The more wedges, the more smooth the arc.
The simplest type of tapered tube can be made from two wedges, or rather one wedge and two half-wedges, cut as so from a rectangle. Again, the dimensions of the rectangle and the angle of the cut lines affect the finished tapered tube.
Examples: many skirts and wrap skirts, like Liz Haywood’s free wraparound skirt pattern, are made from wedges to form a tapered tube.
3. spiral tube
Have you ever made bias tape? If so, then you already know the next technique: sewing a rectangle into a bias tube. You start by making a rectangle into a parallelogram, then rotating it 45° and spiraling it around itself.
Examples: There’s actually a whole book devoted to making patterns like this, Bias Cut Blueprints: A Geometric Method for Clothing Design and Construction by Julianne Bramson and Susan Lenahan. It seems to be out of print and super expensive… anyone have an unused copy laying around that you want to send me? No? Oh well then, next technique:
4. tapered spiral tube
Last but definitely not least is my favorite technique. It took me a while to get my head around the geometry of it and I get a kick out of brain puzzles like this; it’s one of my favorite parts of zero-waste pattern drafting. Basically you wrap a triangle around itself, just like you would with a bias tube above, and you end up with a tapered tube.
The dimensions of the tube look like this: one side of the triangle (highlighted here in yellow) will be the wider end of the tube. The other, smaller end of the tube (highlighted in blue) is part of the line at the opposite corner. The remainder of this line, matched with the third side (highlighted in green) are joined together in a spiral.
Because you start with a triangle, one opening of the tube will be bias and the other will be on grain.
As with all these tubes, the dimensions of the starting shape effect the dimensions of the finished tube. Here are three examples where the ends of the tube (yellow and blue) remain the same, but the spiral edge (green) gets shorter and longer; you can see how the whole tube gets shorter and fatter or longer and narrower.
Another cool bit of math: the angle that the tube widens at is exactly half of the angle of the point closest to the small opening.
Examples: Nau’s Lotus Trousers and Make/Use’s Spiral Trousers are made with this technique. Liz Haywood experimented with using this technique for the sleeves on her Tie-Front Top.
Zero-Waste Pattern Database 