Acta Polytechnica Hungarica Vol. 5, No. 3, 2008 – 75 – Characterisation of Fabric Drape Using Spectral Functions Lívia Kokas-Palicska, Iván Szücs, Zsolt Borka Institute of Fashion, Product and Design, Rejtő Sándor Faculty of Light Industry and Environmental Protection Engineering, Budapest Tech Polytechnical Institution Doberdó út 6, H-1034 Budapest, Hungary kokas.livia@rkk.bmf.hu; szucs.ivan@rkk.bmf.hu; borka.zsolt@rkk.bmf.hu Absract: The article compares the measurement and calculation methods of the fabric drape coefficient used for computer modeling and describes a new parameter. This is the spectral function that is based on fabric drape and it describes the cloth’s 3D plasticity, and ability to be fitted against forms. The new parameter can be used during design as well as during pre-production to for predicting tailorability in the garment industry. Keywords: drape, material testing of cloth’s 1 Introduction The simulation of cloths using computers is an area that is researched long ago. Pre-production computer programs help in the garment industry to make models, series and to develop the garment. The modelling systems also utilize animation tools. The models designed using computers can be ‘dressed’ and they can be moved using preprogrammed human movements. The real behaviour of cloths can be simulated using the animated models to design a model for a given figure, although modelling is a complex task. The plasticity and behaviour of cloths is a complex mechanism, since the interaction of strings and threads result in special attributes. Textil cloths are different from other materials and they are characterised by their aniztropy and their ability to deform under small forces. These charachteristics are mainly due to drape, resistance to bending and shear strain. The behaviour of textile cloths differ from other materials (e.g. paper) due to the differences in there characteristics. To model a textile with a computer simulation, to display a clothing model esthetically in 3D drape is used. Drape is such a deformation that is mainly due to gravitational force while only a part of the textile is fixed. The unfixed part can