The warp direction of a fabric refers to the direction in which the yarns are arranged longitudinally during weaving. Warp yarns are typically drawn from warp beams on a loom and remain taut and stable during weaving. Therefore, warp yarns are stronger, more durable, and have lower elongation than weft yarns. The warp direction determines the fabric's strength and longitudinal shrinkage rate, and is an important reference direction when cutting garment pieces.
The weft direction is perpendicular to the warp direction and is also called the weft yarn direction. Weft yarns are the yarns that pass horizontally through the warp yarns during weaving. They are arranged laterally in the fabric, are relatively loose, and have greater elasticity. Weft yarns affect the fabric's lateral stretch, drape, and wearing comfort; the fabric's stretch and fit must usually be considered during cutting.
The distinction between warp and weft can be determined by observing the fabric's texture and feel. In plain, twill, or satin weave fabrics, the warp yarns are neatly and tightly arranged, while the weft yarns are usually looser. Knitted fabrics, on the other hand, form a mesh structure using warp and weft knitting methods, resulting in differences in elasticity and density between the warp and weft directions. Correctly identifying the warp and weft directions is crucial for cutting, sewing, and fabric use, ensuring the dimensional stability and wearing comfort of the garment.