Fiber types in cloths fiber types in cloths. Clothing fibres are the raw, thread-like structures twisted together to form yarn, which is then woven or knitted into fabrics. These building blocks dictate how a garment feels, stretches, breathes, and holds up over time. Textile fibres fall into three core categories: natural fibres, synthetic (man-made) fibres, and semi-synthetic (regenerated) fibres.