This article examines the dependence of the properties of shape stability of the fabric on the surface densities and porosity of fabrics. Studying the degree of deformation of materials, the formula for calculating the degree of porosity of fabrics and knitwear was substantiated. As is known, in the course of fabric production, under the influence of various forces, some deformation occurs. These changes disappear in the process of weaving, processing on weaving equipment or in the production of finished products from it. They also disappear when worn, when released from the influence of various forces, which is reflected in the structure of the product. Due to these properties, the shape of individual parts of the garment may change. The appearance of the product strongly depends on the composition, the type of rewinding, the phase of formation of the fabric, the force of friction between the threads, i.e., on the shaping properties of the fabric. Studying the stress-strain state in woolen and silk fabrics, it was theoretically justified and experimentally confirmed that the limit of the deformation index in the flexible part is 64-70%.