Learning how to cut on the bias is very important within dressmaking, once you have learnt what it means and how to do it, you will then be able to take on so many more challenges such as piping and more complicated dresses.
To understand the bias, firstly you need to understand some of the other dressmaking terms,
Selvedge- The selvedge is along the side of the fabric. When buying fabric from a roll or a bolt you will have two sides of the fabric with raw edges and two sides with a selvedge. The selvedge stops the fabric from fraying or unravelling. Some manufacturers also print onto the selvedge.
The Grain- The fabric grain is the direction that the fabric is knitted or woven together.
The Bias- The bias is a diagonal direction across the grain of the fabric. When cutting and laying out a pattern it is diagonal to the grain like the ruler demonstrate in the image. This technique is used when making bias binding.