An Energy-based Flattening Technique for Woven Fabrics

Abstract

The fit of garments is an important issue that concerns manufacturers, retailers and consumers with two contributory factors. One is the lack of information and standardisation in relation to the shape of the human body. The other is the craft and skill-based nature of the pattern technology function as performed in most garment manufacturers. Recent advances in body scanning technology are enabling vast amounts of data to be collected for monitoring the demographic variations in the shape of the human body. In addition, commercial software is now available to generate 3D garment specifications. However, one important function to date has not received significant attention. This is the area of generating 2D patterns from 3D design and body shape information. This paper describes work on an algorithm that attempts to generate an optimum pattern while taking into account (i) body shape data, (ii) 3D garment design data, (iii) fabric characteristics, and (iv) tailoring mechanisms for improving fit (dart and gussets) The strategy adopted in this work is to formulate an optimisation function based on flattening energy. Here, flattening energy is defined as that energy required in distorting the fabric of the 2D pattern so that it takes up a specified 3D shape. The fabric behaviour is characterised by a woven structure and the 3D shape is specified in terms of a triangulated surface. Strain constants describe the force versus strain response of the fabric for the weft and warp directions and shear. By analysing the change in geometry of individual surface triangles during the flattening process, the individual strains are evaluated. These are then converted to energy values and summed over all the triangles comprising the complete surface. Tests were conducted by designing panels with different dart configurations on a classical shape (i.e. a torus) covering both hyperbolic and elliptical curvature regions. This was then extended to a size 12 lady's mannequin. Finally, 2D flattened patterns for garment panels with different dart configurations were generated and made-up for a specific fabric. The garment was then put on the actual mannequin and the degree of fit assessed.