Twill is one of the three fundamental types of textile weaves, alongside plain weave and satin. It is created by passing the weft thread over one or more warp threads and then under two or more warp threads, stepping or offsetting the interlacing by one yarn on each successive row. This offset produces the characteristic diagonal pattern, or wale. The structure makes the fabric highly durable, drapeable, and resistant to showing dirt or wrinkles.
Make sure you cut the denim on the straight of grain so the twill line runs exactly at a 45-degree angle to the hem.
The direction of the diagonal line can be either right-hand (running lower left to upper right) or left-hand. Denim is traditionally a right-hand twill.
Related terms
Warp
The set of lengthwise yarns held in tension on a loom before weaving begins.
Weft
The transverse yarns inserted over and under the warp to create a woven fabric.
Plain-woven
Constructed using the simplest over-one, under-one interlacing of warp and weft threads.
Jeans
Sturdy trousers made from denim or dungaree cloth.
Serge
A durable twill fabric woven with a worsted warp and woolen weft, featuring a distinct diagonal rib.