2. PARAMETERS DETERMINING THE PRODUCT APPEARANCE

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1 3D GRAPHICS IN TEXTILE DESIGNING Maria Cybulska, Tomasz Florczak, TU Lodz, Poland ABSTRACT Paper presents application of 3dsmax software in the area of modelling the textile products. The methods and procedures have been developed and implemented allowing for visualisation of different textile products, form fibres and yarns to final products or other products manufactured from the textile components. All procedures use 3dsmax 7 Discreet software tools and the procedures developed with use of "maxscript" programming language 1. INTRODUCTION In the conditions of increasing competitiveness on the textile market, the chance for growth, or sometimes for surviving of the textile industry, are not only the hi-tech products, but also the high quality products, designed for individual end-user, or even designed with the participation of user in the designing process. This approach needs new elastic and dynamic tools, which allow us to change on-lone not only the product appearance and artistic design, but also the raw material and technology used. 3D graphics methods are more and more popular and widely applied not only in entertainment and advertising but also in the field of science and technology. It concerns also the area of textiles Computer programs supporting the process of the product designing such as Sophis [1] support engineers and designers of knitted and woven fabrics. The main advantage of these kinds of products is ability to simulate the final product without costly and time-consuming trials. There are three main disadvantages of existing and available software designated for textiles. The first one is price - dozens of Euro for one specialised programme segment. The second one is the software limitation - software is usually dedicated to strictly determined kind of product - woven or knitted fabric, based on traditional technology. Lack of elasticity and open programming code make them unusable in work on the new technologies or in the companies where two or more different types of textiles are produced. The movie picture art and computer games industries are good source of "open" and flexible 3D graphics software. Paper shows application of 3dsmax 7 Discreet software tools and the procedures developed with use of "maxscript" programming language in the area of simulation and modelling the textile products. 2. PARAMETERS DETERMINING THE PRODUCT APPEARANCE Product appearance is a very complex phenomenon. It is a combined effect of many different factors, as raw material, yarn and fabric structure, finishing and many other parameters resulting in different product properties as, for one hand, aerial mass, stiffness, width and so on. These parameters determine some other factors, as fabric texture or drapeability. On the other hand, the product appearance is determined by light reflection and refraction, translucency, colour, etc. All these parameters should be taken into account in modelling and simulation of the textile product

2 3. 3DSMAX TOOLS Modelling the grid object The basic element of the model of product is a grid object. Its shape depends on geometric properties of modelled element. For instance, in the case of fibre or yarn we can assume it is a kind of cylinder with different types of cross-section - see Figure 1. To create the grid object we can use variety of tools. Combining them we can develop very specific procedures of object formation 3.2 Modification of the object Figure1. Modelling the fibre - exemplary grid objects Among many different implements offered by 3Dsmax, tools for modification of previously created objects play very important role. They enable to change the object structure according to specified parameters of modelled product or to the product technology, for instance by twisting, wrapping or bending the elements or by adding the noise to reflect the product unevenness 3.3. Modelling the surface properties The grid object can be characterised by smooth surface and accidental colour. To create the effect of reality we need to use some tools allowing to determine the texture of the object - smoothness, hairiness, relief, translucency, glossiness, reflection and refraction. 3dsmax offers the wide variety of this kind of tools 1 3ds. max 7 discreet Tutorials, Copyright 2004 Autodesk 3ds. Max 7 - New Features Guide, Copyright 2004 Autodesk

3 Figure 2. Modification of the object surface 3.4. Creating new tool with use of the maxscript language The most important advantage of 3dsmax software is open programming code enabling creation of new specific tools. Script language is similar to some popular programming languages, as C++. Numerous procedures for 3D modelling make the programming easier for inexperienced user or for these who don't know any programming language. It is also possible to develop some procedures, which are not directly related to 3D graphics, as a procedures analysing relationships between some parameters or other mathematical calculations 4. APPLICATION OF 3D GRAPHICS IN MODELLING THE TEXTILE MATERIALS Modeling the textile product can proceed in two ways. The first one starts from the basic element - fibre or yarn. On the basis of predetermined parameters of fibres, yarn and fabric we can simulate the fabric appearance. Alternative method consists in designing the appearance of the final product. Then on the basis of calculations and simulations we can determine parameters of structure and material allowing obtaining the product in desired form. These two methods of modelling we will call accordingly the forward and the backward modelling. Figure 3. Two methods of modelling the textile product

4 4.1. Forward modelling Fibre modelling Procedures have been developed to create models of fibre characterised by different cross-section, diameter and length. Procedures of the material editor were used to determine some surface properties of fibre. All fibre parameters can be further modified accordingly to material properties or to designer needs Modelling the yarn Figure 4. Simulation of the cotton fibre Two different methods of yarn modelling have been developed. The first method consists in giving the linear element the texture with properties determined by yarn structural properties. The presence of fibres is reflected by concavities and convexities on the cylindrical yarn surface. The second one, we could call "real", consists in forming the yarn from previously created 3D models of fibres by wrapping, twisting or nodding them, accordingly to the yarn technology. The method allows setting some predetermined features as yarn unevenness or yarn hairiness for staple yarn

5 Figure 5. Modelling the yarn - A- top- simplified by mapping, B- bottom "real" Modelling the fabric Simulation of the fabric proceeds in two stages. The first one consists in forming the fabric from previously modelled linear elements. One can use both the exact simulations of yarn or yarn modelled by simplified method. In the first case one can get magnified image of fabric with clearly seen fibres. It is also possible to use as a warp or weft the elements plied from two or more linear elements. The elements are interlaced accordingly to the previously chosen weave pattern with the relative position determined by the yarn spacing. The next stage consist in simplifying the 3D model of fabric by converting it to the flat object with texture depending on the properties of the raw material one want to use. The calculation window allows determining some physical properties of fabric, as aerial mass. The method allows for simulation of some fabric patterns obtained both by weaving and printing techniques Figure 6. Modelling the fabric - creating the interlacements according to chosen weave pattern.

6 Figure 7. Dynamic change of some structural parameters of fabric Simulation of the final product Figure 8. 3D model of fabric The last stage of modelling the end product consists in placing the previously designed and simulated fabric on the surface of different kind of 3D objects. These objects are textile products as curtains, carpets, or products the fabric is one of elements, as tapestry on sofa, chair and so on

7 4.2. Backward modelling Figure 9. Simulation of the final product The backward modelling method consists of few stages. At the first stage designer create the fabric as it will look like in the final product. It gives the general fabric appearance and the appearance of the fabric surface. In the next stage it is necessary to determine some parameters of the fabric structure and the structure and raw material of yarn, suitable to obtain the visual effect predetermined by designer. It is also necessary to determine the technology the visual effect can be obtain by - weaving, printing, etc Figure 10. Designing the appearance of the final product

8 Figure 11. Successive stages of backward modelling from product appearance to the raw material 4.3.Complex designing Applying the described above methods it is possible to obtain the technological parameters allowing to produce "a family" of unified textile products of the same design but different structures and designation. The procedures have been developed that make possible to obtain the same patterns by diversified texture, light reflection, colour or translucency of fabric 4. SUMMARY 3D graphics offer excellent tools for visualisation of different kinds of textile products.

9 The methods developed allow simulation of the end product made by any technology. They can be applied not only for designing the textile products. They allow creating presentations for educational purposes, too. They have already found application in creating virtual reconstruction of archaeological and historical fabrics. 2 ACKNOWLEDGEMENTS Research has been subsidised by Polish Ministry of Science and Education 3 RESPONDENCE ADDRESS: Institute of Architecture of Textiles faculty of Enfgineering and Marketing of Textiles, Technical University of Lodz, Lodz, Poland cybulska@wipos.p.lodz.pl 2 M. Cybulska, Florczak T, Maik J Archaeological Textiles- analysis, identification and reconstruction, Proceedings of Autex M. Cybulska, Florczak T, Maik J, Methods of Identification and reconstruction of Textiles in special applications