If you’ve never learned Fabric 101 or need to refresh your memory, this post is written to you. Understanding your fabric and how it works is the first step to creating garments that fit and drape the way you want. We’re going to focus on woven fabric for the time being because woven fabric has the most parts to it.

Fabric Grain… it’s good for you
Fabric grain refers to the direction the threads are woven in a piece of fabric. Woven fabric has 4 directions that have different names. Each direction has a different quality to it and will affect how your finished garment will fit and drape.

The selvage is the finished edges and the fibers that run parallel to the selvage are the warp. They make up the lengthwise grain. Because your fabric will most likely be cut on two edges, the warp will not run back and forth as one continuous thread.

The threads that run perpendicular to the selvage edge are the weft. They make up the crosswise grain. This is the grain that runs parallel to the two raw edges of your fresh off the bold fabric. The weft thread will most likely run back and forth and, when you’re squaring (tutorial to come) you’ll notice that you may have to cut it because at times it is actually woven back and forth as one long continuous thread.

The bias is any diagonal from the lengthwise and crosswise grains.

True bias is a 45 degree angle along the lengthwise and crosswise grains.

Behave!
The lengthwise grain (selvage edge) has very little stretch to it and holds its shape the best out of all the directions. Commercial patterns are marked with arrows that indicate which direction the lengthwise grain should run. The recommended grain line makes it so that your finished piece will behave the way the designer intended. The arrow should be placed parallel to the selvage.

The crosswise grain has a greater stretch to it and this feture makes it ideal to run around the body. It has more give which allows it to form to the body better than the lengthwise grain. This feature also makes it less ideal to drape perpendicular to the floor because over time it will droop, changing the fit of your garment.

The the bias has the best drape and streatch. True bias has the most stretch. Fabric cut on the bias is the most form fitting and designers use bias cut pieces to create beautiful clingy, slinky, and flouncy effects. Fabric cut on the bias has to be treated a little more gingerly because it looses its shape with even minor handling.

So why do you need this?
When you understand the basics of how your fabric is constructed and functions, not only does it give you a higher likelyhood that your finished garment will come out the way the pattern designer intended, it also makes your own designs come to life in the best way possible. When you understand how each direction drapes and holds its shape differently, you are better able to acheive your desired effect and use the fabric to it’s fullest potential.