Computerised pattern making in garment production

T. Bond , in Advances in Apparel Production, 2008

7.8 Material utilisation

Within the PDS system, it is also possible to generate automatically a costing marker which acts as a good basis for estimating fabric costs, given that around 50% of garment cost is associated with fabrics used. The main selling point of computerised pattern design, grading and marker making systems has always been the savings in fabric, achieving a high percentage of material utilisation. Today's CAD systems offer pattern design and grading functions to various degrees of sophistication and speed. There are two methods of making markers within most systems: interactive and automatic. For either method used, data relating to the marker are created in the model file. The file contains information such as the style name, number of graded sizes required, material width, blocking (setting an allowance around the piece perimeter for checked or striped fabrics) or buffering allowances (small cutting allowances), and if required flip and rotation restrictions. The interactive method relies on the user positioning the required pattern pieces over an image that represents the fabric on screen. The pieces to be placed are displayed in a matrix menu either individually or in tabular form. Each size can be viewed in a different colour, in outline or as a filled block. Pieces can be brought into the marker and placed accordingly and can be automatically positioned to the edge of the cloth or the next pattern piece, taking into account any blocking or buffering allowances. The production of the most efficient markers depends on the ability and spatial awareness of the technician.

Fabric widths can be changed to accommodate variations in fabrics supplied: if a marker has been produced and saved for a similar garment, it can be retrieved and displayed on screen for guidance. Alternatively, the marker plan can be copied. Engineering the pattern within the marker-making module is also possible to maximise fabric utilisation. The pattern splits can be vertical, horizontal or at at any specified angle, seam allowances can be automatically added to the modified piece. Examples of pattern engineering may be found on under-collar or facing pieces, generally where the seams are not visible on the outer garment. The length of fabric used and the percentage efficiency are monitored and displayed on screen as each piece is placed. A target efficiency can be preset to act as a guide to achieving the targeted percentage utilisation.

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The interaction of two and three dimensional design in textiles and fashion

K. Townsend , R. Goulding , in Textile Design, 2011

13.2.3 The mass clothed body

Essentially, the relationship a commercial fashion designer has with the body is one based on computerised pattern design systems (PDS) using garment blocks cut to a company's standardised measurements, which are updated periodically through consumer data and national sizing surveys such as SizeUK (2003). Mass produced garments are generally made in sizes 8, 10, 12, 14 and 16. These sizes are based on average dimensions of bust, waist and hip and are designed to accommodate as many body shapes as possible. Companies such as Marks and Spencer, Top Shop and Next supplement their standard ranges with Tall and Petite, reflecting the requirements of their broad customer profile. Creating a wide range of garments in different sizes requires careful selection of corresponding surface embellishments that can be re-scaled to work aesthetically across varying sized pattern pieces.

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Garment pattern design and comfort

P. Watkins , in Improving Comfort in Clothing, 2011

10.2.3 Technology and garment fit

Body scanning for automated measurement extraction and virtual simulation of avatars for garment design and fit and pattern technology is fast developing (D'Apuzzo, 2007; Kirstein et al., 1999; Stylios, 1999; Chittaro and Corvaglia, 2003; Fontana et al., 2005; Krzywinski and Rodel, 2005; Volino et al., 2005; Paquet and Viktor, 2007; Decaudin, 2006; Petrac and Rogale, 2006; Petrac et al., 2006; Wang et al, 2007; Daanen and Hong, 2008; Wang and Tang, 2008, 2010; Wang et al., 2010). Industry leaders majoring on virtual prototyping and fit, and 2D CAD made to measure (MTM) pattern design systems (PDS) include Lectra, Gerber Technologies, Browzwear, Optitex, Dressingsim, Ffitme and Assyst Bullmer. Virtual garment prototyping is highly valuable in reducing time/cost constraints and also has ecological benefits. This technology is intended to increase customer confidence in purchasing a garment appropriate for their body shape and fit preferences but Apeagyei and Otieno (2007) suggest it has some way to go before it can become an accurate fitting tool.

Although virtual avatars allow the consumer to visualise the suggested fit, fabric drape and simulated movement, it is difficult to successfully apply this technology for MTM custom fit garment design. Custom fit PDS are predominantly based on computerised hand pattern production methods. A style pattern, nearest in size to the client's own, is adjusted by substituting the client's measurements at just a few cardinal (primary) points on the pattern profile. 2D pattern pieces that have been adapted using just a few of the customer's length measurements and one-dimensional circumferential measurements (for example bust, waist and hips) are wrapped and seamed together onto a virtual parametric mannequin for fit evaluation. The resulting 3D pattern fitting process does not automatically transpose parametric variations in body shape to the 2D pattern pieces without some considerable behind-the-scenes manipulation. Without this physical intervention, garment fit will not be a true custom fit but a coincidental fit.

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Computer-Aided Design (CAD) and Computer-Aided Manufacturing (CAM) of Apparel and other Textile Products

S. Burke , R. Sinclair , in Textiles and Fashion, 2015

27.1 Introduction

A technical revolution has been taking place in the world of textiles and fashion. Since the 1990s (Aldrich, 2008, p. 192; Jones-Jenkyn, 2011, p. 246), software for use in the fashion and textiles industry has become increasingly sophisticated. Diamond (2003, p. 18) identifies the way in which the fashion industry has been changed by the advent of new technologies and emphasises this 'technology has risen to new heights. Every segment of the fashion industry, from raw materials to the final distribution, to consumer, takes advantage of ever-improving technological discoveries'.

Guerrero (2009) and McCullough (1996) both emphasise that the immediacy of pen and paper as design tools will never be replaced, but that 'it is essential to note the increasingly important role that digital processes are playing in completing the representation of design' (Guerro, 2009, p. 38).

This period of rapid change coincided with the introduction of powerful and relatively inexpensive computers, systems, and graphics software such as Photoshop, Illustrator, CorelDraw, and the use of software such as Excel for costings and production management has encouraged the textile and fashion industry, and the designers who work in these sectors, to use this versatile medium to help create and develop their designs, presentations and clothing ranges, and manage their workflow.

The latest graphics software offers a multitude of tools and techniques for sketching and design, image editing, page layout, and web design. These programs can be used to sketch a simple technical line drawing of a basic tank top or a highly detailed jacket, create the most amazing fashion illustrations, and develop dynamic presentations and page layouts for print and screen. The computer is an extension of one's hand, and an aid to creativity and visualisation.

Computer-aided design (CAD) was initially developed as an interactive computer design system for the textile industry, then introduced into apparel for pattern making and grading, and has been further developed for fashion and clothing design. More recently, powerful graphics software has been integrated into the fashion design process to help to create technical drawings of designs as flats, specification drawings, fashion illustrations and design presentations. This has speeded up the design process and presents a global standard for the visual communication of designs to the production, manufacturing, and marketing sectors within the industry.

Computer-aided manufacturing (CAM) was initially developed as a way of ensuring that the transition from 2D design process to 3D manufacture was more seamless, and also enable companies to benefit from quick responses (Diamond, 2002). The requirement to interlink the design and manufacturing processes can be seen specifically in the area such as knitting, in 3D knitting processes, weaving, and embroidery. For the textile designer, the ability to design, virtually check, and then send the design direct to the machine enables a more seamless process. Just as CAD enables design businesses to participate within a global field, so does the ability to integrate CAM, which enables companies to test physical prototypes (Jones-Jenkyn, 2011) and streamline production processes.

The advent and progression of the virtual world has united fashion with gaming and software technologies, such as the development of Avatars, online spaces such as Second Life, software such as Poser, online rendering, testing and virtual fit, and pattern sewing as seen in software such as Optitex and Marvellous Designer. Such technologies have and continue to be employed directly in fashion development and marketing, such as fashion company H&M's use of SIMS in its Fashionista program.

It is important for designers to recognise that the use of the computers in fashion and textiles is not just limited to the design of garments; such technology is used prevalently throughout the whole fashion and textile industry.

The CAD/CAM process can be viewed in the following ways for the development of a design from inception to manufacture:

1.

Connectivity: The need for companies in design (buyers, designers, suppliers), production (manufacturers) and retailing (e-commerce/e-tailing) in the design and production chain to communicate in a global market.

2.

Design creation/ideation: Through image/mood boards, designs, virtual fabrics/clothing, flats.

3.

Production data management: The ability to use product data management (PDM) software to control the whole production cycle of a garment. This type of software allows tracking of the workflow and identification of the status of an individual garment at any one time.

4.

Pattern design: This is divided into two areas, one being the specification drawings, the second at PDS (pattern design systems). It is in these systems that the pattern is generated for a garment.

5.

Garment sampling: At this stage, the pattern created in the PDS can be modelled in both physical patterns and 3D virtual systems. In these systems, garments can be virtually stitched together, tested for fit in a virtual environment, and then even visualised on virtual runways. It is also at this stage that patterns can be exported to digital textile printing machines, and prototype garments produced.

6.

Sizing: The advent of body scanners had led to an increase in made-to-measure clothing, leading companies to develop mass customisation as a process for ensuring better customer fit, style, and options.

7.

Pattern grading: Pattern grading systems now mean that the processing of patterns is leading to more streamlined process for pattern making. Pattern grading is done by inputting pattern data, creating the grading criteria, grading the pattern, and then sending this data to the production planner.

8.

Production: Here the data created at the pattern grading stage is converted into a production pattern, known as production lay planning and marker making. Using the software the pattern can be specifically laid to create the best efficiency for cutting out, and lower costs especially related to material waste.

9.

Plotting and cutting: Companies now utilise CAM systems to enable the accurate cutting out of garments and production pieces. These systems also enable companies to review waste management in terms of fabrics.

10.

Product life cycle: Product lifecycle management (PLM) software that can be accessed on a global basis is database software enabling companies to view all aspects of a product from design to finish. It is usually integrated with PDM system software. This allows companies to monitor the styles to market, the workflow and the sales, from design inception to completion.

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Sizing systems, fit models and target markets

J. Bougourd , in Sizing in Clothing, 2007

4.7.4 Virtual fit models

Virtual fit models may be generated as follows.

1

As avatars, using computer graphics.

2

As captured from existing shapes, using stereo, 3D scanners, videos or cameras.

3

By using existing sets of either to generate new models.

Representations derived from real life are regarded as superior to the static and unrealistic computer images with which we have been familiar, although highly realistic virtual human models are becoming commonplace in computer graphics (Magnenat-Thalmann et al., 2004). For ready-to-wear fit testing, an accurate real-life image may be generated to represent a specified set of measurements or shapes, individual fit models or a group of scans representing a target market. These virtual models can be used to test fit at several stages during the clothing, product development, production and consumption process. The stages might include block patterns, styled patterns, 3D designs and 2D pattern generation, virtual garment prototyping, prototype designs, online shopping and in-store shopping. Each is discussed below, with references to some of the companies engaged in relevant development.

Block patterns (three-dimensional scans to two-dimensional patterns)

Product-specific 2D block patterns can be created on a 3D scan with options to vary silhouettes and degrees of fit and ease (by, for example, [TC]2). Practitioners are able to assess the size, shape and fit of a base pattern and to customise lengths and shape at an early stage of style development. The automatically generated pattern can be imported to any pattern design system, where more complex styling and construction features can be added ( Anderson, 2005).

Styled patterns (two-dimensional patterns to three-dimensional scans)

New approaches to styled patterns are being introduced. 2D styled patterns can be fitted (wrapped) around a 3D scan, the fabric simulated, the style fit tested and the pattern altered before a physical garment is cut and sewn (Optitex, Browzwear, Bodymetrics and PAD Systems). A similar system enables designers and pattern technologists to assess the fit and style of a garment using 3D prototyping directly from the topography of the pattern. The system uses the pattern data to drape a 3D garment onto the 3D model; the fabric properties are integrated to present a realistic drape (Anderson, 2005).

Three-dimensional design and two-dimensional pattern generation (three-dimensional designs to two-dimensional patterns)

3D scans generated from fit models can be made symmetrical and used to create 3D designs directly onto the virtual 3D fit model (Fig. 4.10). There are two developments to note. The first uses elastomerics for contoured sportswear and intimate apparel, where materials can be selected from an integral database and 2D patterns are unwrapped from the 3D design. The fit and ease can be adjusted to reflect the mechanical properties of the fabric, and also the way in which those properties are used in the design, the size and the shape of the virtual model (Heyd, 2004; Krzywinski et al., 2005). The second system, by Kung (2005), offers a 3D-to-2D computer-aided-design solution to directly create virtual garments. The system enables the silhouette and fit characteristics of a garment to be created and adjusted using a 3D template on a 3D virtual model, which can be generated from human fit models, or a model derived from a clearly defined target group of customers. The software provides a means to control and experiment with the fit of a garment in 3D space while simultaneously generating a corresponding 2D pattern. The fit of the garment follows the human body, and not data files or size charts; the actual body, the virtual body and the pattern are directly aligned. The drape of the garment can be adjusted according to the intended fit, the material chosen or the necessity for a required freedom of movement by, for example, moving the arms forwards, thereby increasing the measurement across the back. 'The main innovation of TPC [3D pattern concept] is the creation of garments in 3D [virtual] space, on a virtual body. In short, it is now possible to create [virtual] garments directly from 3D body scan data.' It is claimed that the system can predict size progression and ensure garment fit and comfort; if this is the case, the development could render traditional grade rules superfluous (Kung, 2005).

4.10. 3D-to-2D design and pattern generation

 (source: Lectra; see Heyd (2004))

Virtual garment prototyping (three-dimensional computer-generated model to three-dimensional prototype)

The virtual garment prototyping, with automatic fitting tools offers an interactive system for fashion designers. The design simulation tool allows the designer to experiment virtually with new collections via high-quality preview animations as well as enabling pattern technologists to adjust precisely the shape and measurements of the patterns to fit the body and maximise comfort. Systems fit the garment automatically and, by using a fitting control tool, the operative can preview fabric deformations and tensions along any weave orientation and preview pressure forces in the garment on the body skin. Any change that is made to the pattern, design and sizing can be automatically evaluated by a mechanical 'comfortability tool'. These virtual fit evaluations can be conducted on both static and animated bodies (Volino and Magnenat-Thalmann, 2005).

Physical prototype garments (three-dimensional garments to three-dimensional representations of a fit model wearing garments)

This system uses digital representation of a physical garment. Digital images, captured by video, can transport highly detailed images of a live model wearing a garment. The software creates rotating 3D images that can be posted to a website, viewed in a simulated 3D manner, manipulated and magnified and can immediately be appraised by buyers. Fittings can be completed using these visual images, by viewing either locally or offshore.

Online shopping

While major developments have helped to improve the fit of garments through the use of virtual models during the product development and production process, the creation of virtual models for online shopping applications still presents a challenge. A study of the return of goods by dissatisfied customers, reported by Hammond and Kohler (2002), mirrors rates for catalogues and indicates a three-tiered problem: casual apparel, 12–18%; more fitted fashion, 20–28%; high-fashion apparel, up to 35%. These figures show that it can be difficult to convince shoppers to purchase fashion products online. Efforts to improve the visualisation of apparel characteristics include the use of specialised colour accuracy and consistency tools, and zoom technology to enhance the viewer's understanding of design and style features. The question of poor fit is being addressed through 'fit calculators' or 'fit ratings' and by mapping consumer measures to apparel brands, styles and sizes. Size-predictive methods are offered using 2D and 3D models, and some have iterative tools that can be programmed to match customer shape, size and appearance. The 18–25 year olds form a key online shopping audience that might also find the new virtual fit technologies under development exciting and effective. Predictions for sales in 2005 were US$13.8 billion, and it is expected that, by 2010, 12% of apparel sales will be online (Wagner, 2005). However, the fact that it is not possible to touch or feel products remains a major inhibition to sales over the Internet, other than for basic (or non-fashion) items (Kurt Salmon Associates for the International Wool Textile Organisation, 2005).

In-store shopping (three-dimensional scan to three-dimensional garment)

3D scanners are being located in retail environments to give instant shape, size and fit evaluations for ready-to-wear ranges of jeans. Some systems use a 2D-to-3D process where the customer is scanned and the scan imported to a visualisation system where 2D patterns of selected jeans are virtually wrapped around the scan of the customer (e.g. Bodymetrics). Other systems are being used for made-to-measure clothing, where garments are fitted automatically to the 3D scan of a customer by using landmark information on a body scan. Using a similar process (described by Volino and Magnenat-Thalmann (2005)) the systems show stretch, shear and bend forces of the simulation model. These virtual fit evaluations can be conducted on both static and animated virtual bodies, e.g. bending (Spanglang, 2005).

The use of the virtual fit model brings a number of benefits to garment fit sessions. One is the ability to use fit models based on 3D body scans that represent a target market, rather than unrealistic computer-generated graphic models. Patterns and designs generated from realistic human models have the potential to provide excellent fit. They are more accurate and give opportunities to fit garment component layers as well as to visualise and fit completed garments. What is available on some systems is a facility to alter either the design or the pattern on the model, tools that automatically generate graded patterns to fit the sizes and shapes in each size of a target market.

Interest in using virtual fit models at different stages in the product development, production and consumption process is prompted, in part, by the consumer's wish to be provided with a continuous supply of new products. It has created a demand chain, and that has made it necessary to reduce the time that it takes to move from concept to market (Kurt Salmon Associates for the International Wool Textile Organisation, 2005).

All the approaches described have the potential to support that aim. They promise to help to improve garment fit prior to a garment being made, and help to reduce the following.

1

The costs associated with garment manufacture.

2

The number of physical fit sessions needed (estimated by one company as a reduction by 50%).

3

The number of samples that need to be shipped for fitting.

Other benefits were identified as the ability to create designs more quickly, the reduction in the time for garment approval, the improvement in the collaboration between departments (responsible for design, manufacture and merchandising) and the creation of opportunities for companies in the supply chain (perhaps separated by continents) to participate in global fit sessions.

The availability of the virtual fit model brings a considerable advance to both the process and the accuracy of fit testing. They do not, however, offer all the benefits of using a live fit model; there are some visual, tactile and physical aspects of fit that cannot, as yet, be adequately evaluated in a virtual environment.

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