Fabric is a kind of flat film block composed of thin, small and soft fabrics by crossing, winding and connecting. Woven fabrics are made up of yarns that cross each other. Knitted fabrics are made up of yarns with kinking relationship. Nonwovens are made up of connected yarns. Thirdly, the fabric is made up of yarns with cross / kink relationship. 

Many yarns form a stable relationship to form a fabric. There are three kinds of stable structure relations which can be formed by yarn: crossing, winding and connecting. Keep the fabric stable in shape and specific mechanical properties. By analyzing the yarn group in fabric and its running direction, running law and forming relationship, we can clearly understand all kinds of fabrics.