外文翻譯——專用服裝三維CAD模型

1、服裝設(shè)計中的計算機輔助方法三維計算機輔助設(shè)計（ CAD ）技術(shù)正逐漸擴散到服裝的設(shè)計和制造應(yīng)用領(lǐng)域。目前，服裝行業(yè)普遍使用的二維CAD工具。預(yù)計，三維設(shè)計工具，將成為未來服裝行業(yè)中不斷發(fā)展的技術(shù)。服裝產(chǎn)品的設(shè)計的基本問題是合體性的問題以及相關(guān)的二維圖形生成的問題。最終目標(biāo)是設(shè)計和生產(chǎn)非常合體的個性化服裝，而三維方法是通過努力可以實現(xiàn)這一目標(biāo)的最合理的辦法。三維方法包括幾個關(guān)鍵因素：其中包括參數(shù)化三維人體模型;三維服裝模擬;三維圖案設(shè)計，并3D/2D模型轉(zhuǎn)換。做這個課題的目的是提供一個平臺，供研究人員回顧過去的技術(shù)發(fā)展，并為今后研究三維服裝設(shè)計方法找出可能的方向。這里選擇了題目相關(guān)的五篇論文，為

2、服裝行業(yè)提供三維應(yīng)用程序發(fā)展的背景和技術(shù)。第一份文件是一個粗略的審查織物仿真技術(shù)，該技術(shù)奠定了基礎(chǔ)的三維服裝設(shè)計。接下來的三篇論文詳細(xì)介紹了虛擬的環(huán)境中的三維服裝設(shè)計。最后一篇介紹了將三維服裝轉(zhuǎn)換為二維樣板的新技術(shù)。第一篇論文是從Choi and Ko得到的，有關(guān)織物仿真研究問題。作為一項服裝設(shè)計和修改的基本技術(shù)，物理為基礎(chǔ)的織物仿真技術(shù)被用來產(chǎn)生織物運動的逼真效果。這篇論文介紹了織物仿真技術(shù)的三個方面：（1）服裝結(jié)構(gòu); （2）基于物理的模擬，和（3）碰撞檢測和響應(yīng)。所面臨的技術(shù)挑戰(zhàn)，即創(chuàng)造更多的實際成果;實現(xiàn)更快的運行時間，制造/模擬更為復(fù)雜的服裝，是需要進(jìn)一步研究的突出問題。Volino等

3、在第二篇論文中提出的，是一個框架，它符合服裝行業(yè)虛擬服裝設(shè)計和原型制作的需要。他們的做法集中在交互設(shè)計，模擬和可視化功能。作為先進(jìn)的虛擬服裝仿真技術(shù)在過去十年中的總結(jié)，本文中介紹的框架集成了國家最先進(jìn)的具有創(chuàng)新設(shè)計工具的物理模擬算法，提供高效率和高質(zhì)量的服裝設(shè)計和原型制作程序。第三篇論文介紹了一個綜合的環(huán)境，這使得設(shè)計師能夠通過分析服裝虛擬原型和仿真結(jié)果驗證他們的風(fēng)格和設(shè)計方案，因此，物理原型的數(shù)量和作用會減少。和上一篇論文中提到的一樣，本文介紹的服裝虛擬原型的制作方法也是以物理為基礎(chǔ)的。他們能夠建立模型確定各向異性織物的經(jīng)緯向性能。牛頓動力學(xué)的限制適用于網(wǎng)格，以確定最后形成的合體服裝的形狀。

4、本文中提到的通過應(yīng)用研究和對幾個男女性服裝項目中CAD建模和物理模擬的分析，用來證明他們的系統(tǒng)功能。在第四篇論文中，作者提出了一種同步三維服裝仿真結(jié)果更新算法，用于二維服裝紙樣設(shè)計的修改。用這種做法，對二維模式的修改無須每次重復(fù)整個三維服裝合體性仿真，樣板修改過程的效率被大幅度提升了。該算法的另一個優(yōu)勢是，二維服裝紙樣的網(wǎng)格拓?fù)浣Y(jié)構(gòu)被保存，從而通過保持矩陣方程一致性簡化了數(shù)值格式。為了把用戶制作的三維服裝轉(zhuǎn)變成良好的二維板式，麥卡特尼等人在第五篇論文中介紹了一種方法。他們的算法，通過采用一個正交應(yīng)變模型來轉(zhuǎn)換鎖定在不可更新的能量函數(shù)中的應(yīng)變值。這些能源函數(shù)通過平坦約束三角網(wǎng)格被盡量減少。因為他

5、們的應(yīng)變模型各向異性，其方法可以處理正交異性材料的平坦問題，這對服裝生產(chǎn)中三維模式轉(zhuǎn)變?yōu)槎S模式是非常重要的。他們的論文中也考慮了接縫插入問題。在這里，我們要感謝對這些論文提供了寶貴的意見和見解的審評者。這些論文表明，三維CAD技術(shù)在服裝設(shè)計中正在迅速成熟，將成為彌補學(xué)術(shù)研究和商業(yè)應(yīng)用在設(shè)計和制造服裝產(chǎn)品中差距的橋梁。盡管仍有物理模擬、碰撞檢測、 3D/2D轉(zhuǎn)換、高效的設(shè)計界面領(lǐng)域的技術(shù)需要改善，但是我們希望這一復(fù)雜的服裝設(shè)計任務(wù)可以通過CAD系統(tǒng)在不久的將來完成。CAD methods in garment designThree dimensional Computer-Aided-Des

6、ign (CAD) technology is gradually diffusing into the garment design and manufacturing applications. At present, the apparel industry widely uses two-dimensional CAD tools. It is anticipated that three-dimensional design tools will be the next evolving technology for the apparel industry. The basic p

7、roblems in apparel products design are the fitting problem and the related 2D-pattern generation problem. The ultimate goal is to design and produce well-fitted personalized garments for individuals, and the 3D approach is the most rational approach to be adopted to realize this goal. The 3Dapproach

8、 consists of several key elements, which include parameterized 3D-mannequin modeling; 3D-garment simulation;3D-pattern design, and 3D/2D-pattern conversion.The aim of this special issue is to provide a forum for researchers to review the past developments, and to identify possible directions for fut

9、ure research on 3D-approaches to garment design. The five papers selected for this special issue provide background and techniques for 3D-applications in the apparel industry. The first paper serves as a cursory review of cloth simulation technology which lays the foundation of 3D-garment design. Th

10、e following three papers show techniques for 3D-garment design in a virtual environment. The last paper in this special issue gives a novel technique to convert 3D-garment pieces into corresponding two patterns.The first paper is a review paper from Choi and Ko on research problems in cloth simulati

11、on. As a fundamental technique for the design and modification of apparel items, the physics-based cloth simulation technique is used to generate realistic cloth motion in real-time. Three technical aspects of cloth simulation are reviewed in this paper: (1)garment construction; (2) physically based

12、 simulation, and(3) collision detection and response. The technical challenges, namely creating more realistic results; achieving faster running time, and constructing/simulating more complex garments, are highlighted as the problems requiring further research.Presented in the second paper by Volino

13、 et al. is a framework which fits the needs of the apparel industry for virtual garment design and prototyping. Their approach concentrates on interactive design, simulation and visualization features. As a result of the advances in virtual garment simulation technologies in the last decade, the fra

14、mework presented in this paper integrates the state-of-the- art physical simulation algorithms with the innovative design tools to provide an efficient and quality garment design and prototyping procedure.The third paper describes an integrated environment, which allows designers to validate their s

15、tyle and design options through the analysis of garment virtual prototypes and simulation results, so that the number and role of physical prototypes are reduced. In line with the previous paper, the garment virtual prototyping method presented in this paper is also physics-based. They define the pa

16、rticle mesh associated with each fabric panel as a structured 2Dgrid whose coordinates aligned with the directional anisotropic warp and weft properties of the fabric. The constrained Newtonian dynamics is applied to the mesh to determine the final shape of a fitted garment. Applications and case st

17、udies, with analysis of CAD modeling and physical simulation results of several male and female garment items, are shown in the paper to demonstrate the functionality of their system.In the fourth paper, a synchronous 3D-garment simulation result updating algorithm is presented for 2D-garment patter

18、n design modification. With this approach, the 3Dgarment fitting simulation is not required to repeat the entire simulation for every 2D-pattern modification, the efficiency of the pattern modification processing is greatly enhanced. Another advantage of the proposed algorithm is that the mesh topol

19、ogy of the 2D-garment pattern is preserved and thus simplifies the numerical scheme by maintaining the consistency of the matrix equation. In order to determine good fitting two-dimensional flattened patterns from user defined three-dimensional surface regions, an approach is presented by McCartneye

20、t al. in the fifth paper. In their algorithm, an orthotropic strain model is adopted to convert the strain values locked in undevelopable regions to energy functions. These energy functions are minimized by flattening of constrained triangular mesh. Since their strain model is orthotropic, their met

21、hod can handle the flattening problem of orthotropic materialsthis is very important for converting 3D-pieces into 2D-patterns for apparel manufacturing. The seam insertion problems are also considered in their paper.Here, we would like to thank the reviewers who provided valuable comments and insig

22、hts for all papers in this special issue. The papers in the special issue indicate that the 3D CAD approach in garment design is fast approach maturity that will bridge the gap between academic research and commercial application in the design and manufacturing of apparel products. There still remai

23、ns improvement in the areas of physics-based simulation, collision detection, 3D/2D-conversion, and effective design interface, but we would expect that the complex garment design tasks could be virtually completed by CAD systems in the very near future.專用服裝三維CAD模型摘要： 雖然可用于服裝計算機輔助設(shè)計（ CAD ）系統(tǒng)的織物建模技術(shù)已

24、取得相當(dāng)進(jìn)展，但是很少有人研究服裝CAD系統(tǒng)中指定服裝的方法。服裝的最后造型是通過省道、接縫、邊緣、襯墊和織物的局部延伸得到的。為了贏得信譽， CAD系統(tǒng)應(yīng)當(dāng)可以通過簡單的界面來指定施工細(xì)節(jié)，并且有強大的功能處理復(fù)雜的服裝配件?？尚械母拍罘椒ㄓ泻芏唷Ｖ灰袦?zhǔn)確懸垂算法，被選擇面料的服裝樣板就可以簡單地附著在模特兒上，實現(xiàn)服裝的可視化。如果有必要變化，用戶將修改二維樣板并重新運行可視化程序。另一種可能更富有成效的辦法是用先進(jìn)的繪圖工具指定在3維環(huán)境下指定所需要的三維形狀。三維服裝會利用某種方式轉(zhuǎn)化為二維樣板并標(biāo)明實現(xiàn)所需的最后形式的結(jié)構(gòu)細(xì)節(jié)。本文介紹的計算機輔助設(shè)計系統(tǒng)，正在努力實現(xiàn)上述過程。1

25、 介紹計算機輔助設(shè)計（ CAD ）現(xiàn)在是一個發(fā)展了很久的技術(shù)，目的是為工程應(yīng)用產(chǎn)生使用的設(shè)計方案。早期系統(tǒng)只是代替了繪圖板和繪圖工具。然而，現(xiàn)代CAD系統(tǒng)包含了許多分析工具，可以協(xié)助設(shè)計人員優(yōu)化設(shè)計或?qū)λ麄兊脑O(shè)計進(jìn)行功能測試。此外，生產(chǎn)信息可以快速的從CAD設(shè)計中得到。計算機系統(tǒng)輔助服裝生產(chǎn)的技術(shù)直到今天一直在發(fā)展。服裝設(shè)計系統(tǒng)的研究集中在服裝的可視化，以及需要很快的產(chǎn)生設(shè)計形象。這種系統(tǒng)已證明對制造服裝的企業(yè)非常有效，他們?yōu)橛写罅控浳锒冶仨殢念櫩吞幒藢嵲O(shè)計的大型零售機構(gòu)生產(chǎn)。CAD系統(tǒng)能夠迅速嘗試不同的顏色和紋理，這種功能在這種情況下是非常寶貴的。而且，這種系統(tǒng)能夠使用最新的打印機技術(shù)在原

26、型上產(chǎn)生紡織品印花。此外，它的自動化程度很高，可在后續(xù)的生產(chǎn)過程中自動生成二維樣板和樣板的裁剪路徑。仍然存在著三個計算機輔助設(shè)計很少涉及或沒有取得成功的領(lǐng)域。1 、電腦產(chǎn)生完整的三維服裝。2 、自動生成二維樣板。3 、精確敏感的模擬服裝面料的視覺感受并自動產(chǎn)生加工方法。 這些領(lǐng)域發(fā)展緩慢導(dǎo)致了企業(yè)無法真正采用計算機集成方法設(shè)計和制造服裝。這篇論文的目的為服裝設(shè)計加工一體化過程提供可行的過程，重點介紹用戶界面和促進(jìn)一體化的核心技術(shù)。2 發(fā)展現(xiàn)狀和局限大多數(shù)生產(chǎn)大中批量的服裝制造公司的當(dāng)前情況可以用圖1來描述。設(shè)計師根據(jù)以當(dāng)前的流行趨勢產(chǎn)生的創(chuàng)作主題和目標(biāo)市場設(shè)計產(chǎn)品。他們通常把設(shè)計畫在紙上，表達(dá)

27、服裝的視覺效果。有時候設(shè)計稿上會附有加工時要用的面料樣本。需要指出的是，這種設(shè)計形式既不能被當(dāng)做準(zhǔn)確的服裝結(jié)構(gòu)，也不能被當(dāng)做三維服裝的二維展開圖。 設(shè) 計 設(shè)計紙稿 制作樣板 紙樣 樣衣制作 樣衣評價和評估 圖1 普遍使用的服裝設(shè)計流程因此，這意味著設(shè)計的溝通往往是非正式的，但對進(jìn)行下一個生產(chǎn)階段足夠已經(jīng)詳細(xì)。這種情況的主要限制有兩個方面。 1、制板師在制作二維樣板時對設(shè)計的解釋帶有主觀性。 2、其次，通過評估階段的設(shè)計作品比例較低。這樣做結(jié)果不僅是拒絕了大量的樣品，更重要的是，浪費了時間和分散了精力。3 計算機集成方法這里提出的方法在圖2中表示了出來?？驁D描述了計算機集成方法的核心要素。至今

28、為止阻礙這樣一種綜合方法被接受的關(guān)鍵因素是：沒有一種有效的設(shè)計界面，可以讓設(shè)計師方便的創(chuàng)造三維服裝；  沒有功能強大的把三維服裝變成二維樣板的軟件；  沒有準(zhǔn)確的懸垂效果顯示技術(shù)。 為了順利的實現(xiàn)集成制造過程，以上三方面的技術(shù)都要有較大發(fā)展。下文將詳細(xì)介紹這些因素。3.1 設(shè)計界面設(shè)計功能在服裝行業(yè)是一個創(chuàng)造性和藝術(shù)性的過程。任何提供給設(shè)計人員的計系統(tǒng)，不得抑制設(shè)計人員的藝術(shù)天賦。然而，設(shè)計者必須根據(jù)某些因素，例如成本和最終產(chǎn)品的功能，進(jìn)行設(shè)計。增加在這些困難上的是服裝在穿著時的復(fù)雜形狀變化。設(shè)計師應(yīng)當(dāng)通過設(shè)計界面向計算機表達(dá)什么形狀？本文提供的是一種全

29、新的界面，可以生成三維服裝模型.這種模型在合體性要求高的地方必須能夠提供準(zhǔn)確的表面描述，例如服裝接近基本模特的地方。這種表面描述必須能夠通過合適的人機交流界面和數(shù)學(xué)技術(shù)實現(xiàn)。然而，讓設(shè)計人員描述布料懸垂的三維幾何形狀是不恰當(dāng)?shù)摹AD系統(tǒng)使用的技術(shù)（如各種形式的雙三次曲面）一定要能夠準(zhǔn)確地表現(xiàn)織物懸垂的形狀，而不是讓設(shè)計師完成這些工作。其次，為了準(zhǔn)確地預(yù)測或想象服裝的形狀，設(shè)計師非常了解面料的性質(zhì)。為了設(shè)計界面，在圖3 （a）中的表述可以被認(rèn)為是初始服裝的風(fēng)格形式，包含施工生產(chǎn)所必需的所有的細(xì)節(jié)。CAD服裝三維效果樣板展開電腦生成的樣板樣板優(yōu)化系統(tǒng)生產(chǎn)樣板懸垂引擎服裝可視化評價面料特性拒絕接受

30、重設(shè)計不適用圖2 建議使用的服裝設(shè)計方式由于設(shè)計師不能準(zhǔn)確的描述服裝的每個細(xì)節(jié)，因此設(shè)計界面應(yīng)當(dāng)提醒設(shè)計師界定其他細(xì)節(jié)。例如，如果選中了兩個毗鄰的小組件，那么系統(tǒng)應(yīng)當(dāng)詢問它們應(yīng)當(dāng)怎樣被連接。而且所以設(shè)計的面料屬性都要被確定。實際上，這一階段應(yīng)確定所有參數(shù)以便進(jìn)行隨后的懸垂仿真。在這個階段顯示的服裝三維表面有兩個重要的作用。首先，它提供了一個三維框架，在這個框架中，樣板的關(guān)系才能通過服裝組成被充分確定。此外它為懸垂性模擬提供了一個很好的起點。因此，通常用來定義一個樣板的樣板節(jié)點將有三重作用：1、 作為初始的三維樣板的節(jié)點；2、 作為被轉(zhuǎn)化成的二維樣板的節(jié)點；3、 作為樣板懸垂性模擬的節(jié)點。3.2

31、 樣板展開曾有人試圖做出生成服裝二維樣板的軟件。然而，這些努力幾乎沒有結(jié)果，因為二維樣板的生成需要一個完整的3D模型。此外，必須有一個智能化檢驗系統(tǒng)驗證樣板展開過程是否足夠精確。作者建議，服裝3D模型應(yīng)當(dāng)被自動分成合體和懸垂兩部分。檢驗服裝屬于哪部分的標(biāo)準(zhǔn)是服裝與模特是否被抵消，以及服裝被迫抑制這種抵消的程度。根據(jù)這一劃分，展開過程中合體部分和懸垂部分被分開對待.另一個重要因素是織物的材料特性。由于面料通過梭織或針織結(jié)構(gòu)產(chǎn)生各向異性特性，這是個難以解決的問題。最后，二維扁平樣板不只是一個二維輪廓。需要有一個服裝如何從三維到二維映射的說明，這樣，需要考慮懸垂性時，反向進(jìn)程可以實現(xiàn)。有人研究過，三

32、維模型轉(zhuǎn)變?yōu)槎S的平坦算法。該算法能夠根據(jù)相關(guān)的曲率特性處理任意位置的接縫，包括省道和節(jié)點。3.3 懸垂引擎此模塊應(yīng)能處理以下信息：1、一個二維模式的幾何描述（包括足夠的內(nèi)部點以及與其他件的連接方式） 。2、通過主要特點描述確定的織物種類。 3、制約機制，如肩帶，拉鏈。 4、人體模特表面曲面描述。 5、表面紋理描述。 并且能夠準(zhǔn)確預(yù)測織物的最后形狀。這是一個非常困難的要求大量計算的過程。有些人研究過其它方法。作者們所采取的模式必須能模擬服裝穿著時的各種耗能方式。這是研究拉伸剛度、抗彎剛度和屈曲行為得到的成果。能夠用來準(zhǔn)確描述材料特性的參數(shù)是：經(jīng)紗的方向拉伸應(yīng)變能量不變，Ksu；緯線方向拉伸應(yīng)變

33、能量不變，Ksv；裁剪應(yīng)變能量不變，Kr；平面彎曲能量不變，Kb；由織物單位質(zhì)量產(chǎn)生的潛在能量，Kg。已經(jīng)出現(xiàn)了模型，可以根據(jù)面料性質(zhì)測量以上幾個參數(shù)。當(dāng)3D系統(tǒng)中的某個節(jié)點的運動會減少總能量，問題就出現(xiàn)了。系統(tǒng)必須不斷的檢查，確保服裝樣板的節(jié)點與下面的模特兒不重合。這個問題可以通過在上述清單中另加入一個能量部件解決，它可以糾正與模特重合的樣板節(jié)點。此外，三維樣板有時會和自身重合。這些因素大大增加了計算的復(fù)雜性。該模型，體現(xiàn)出能源和幾何造型元素，稱為懸垂引擎。表現(xiàn)的方法和關(guān)閉它的方法對形成樣板的最終形狀是很重要的。以往在這方面的工作突出了解決方案對計算要求嚴(yán)格的特點和在三維下解決方案的敏感性問

34、題。4 例子圖3. a.三維板式設(shè)計 b.樣板網(wǎng)格化 c.樣板展平 d.懸垂效果和服裝紋理材料特性A類材料B類材料經(jīng)紗的方向拉伸應(yīng)變能量，Ksu（N/mm）0.4110.182緯線方向拉伸應(yīng)變能量, Ksv（N/mm）0.4340.882裁剪應(yīng)變能量，Kr（N/mm.rad）0.0260.017平面彎曲能量，Kb（N/ rad）5.8×10-42.1×10-4由織物單位質(zhì)量產(chǎn)生的潛在能量，Kg（N/mm2）1.56×10-62.088×10-6表1.面料材料性能舉例假設(shè)一名設(shè)計師要設(shè)計貼體服裝的右前樣板。這需要理想的三維表面和為了達(dá)到貼體性而可選擇的省道

35、位置。以下是兩個實例。由于本例的服裝不是可以完整的款式，所以需要固定某些點，防止啟動懸垂引擎時，服裝脫落。圖3（a）展現(xiàn)了在理想的三維表面生成的初始服裝樣板和固定點（分有A，B，C和D）。這個例子中沒有確定省道。在這一階段，表面由多邊形網(wǎng)格展現(xiàn)出來。網(wǎng)格的性質(zhì)顯示在圖3（b）中。 兩種面料類型A和B被考慮，它們的性質(zhì)在表1中被定義。面料A在第一小組中。然后平坦進(jìn)程開始，以獲取二維樣板。從三維到二維轉(zhuǎn)化的過程中，初始三維網(wǎng)格中的每一個節(jié)點被一對一的映射 （圖3 （ b ）。其結(jié)果在圖 3（c）中展示。最后，懸垂引擎被啟動。這個過程始于最初三維樣板圖3（a），盡量減少二維平坦面料轉(zhuǎn)化為目前的三維形

36、狀時需要的總能量。最后懸垂后的三維形狀在圖3（d）中展示，樣板的A，B，C和D點被固定了。為了使視覺效果變得更好，織物紋理被渲染。這個功能因為懸垂引擎的2D-3D映射被加強。圖4. a.三維板式設(shè)計 b.樣板網(wǎng)格化 c.樣板展平 d.懸垂效果和服裝紋理第二個例子在圖4（a）（d）中被展示。在這個例子中，應(yīng)用了另一種布料（B型），而且一個省道在樣板的三維模式中被確定了出來（圖4（a）。為了保留整個省道的幾何形狀，原始的三維樣板被網(wǎng)格化（圖4（b）。這使得平展過程可以進(jìn)行（圖4（c）。在展平過程中，省道上的節(jié)點被雙重化，這樣省道才能形成。啟動懸垂引擎時，省道上的節(jié)點被固定在同樣的3D位置。最后的結(jié)

37、果如圖4（d）所示。5 結(jié)論本文簡單介紹了服裝生產(chǎn)中的集成制造技術(shù)。設(shè)計界面、平展技術(shù)和懸垂性已被認(rèn)為是阻礙技術(shù)發(fā)展的主要困難。例子中表現(xiàn)了服裝最終形狀怎樣受到面料性質(zhì)和省道等工藝技術(shù)的影響。為了使CAD系統(tǒng)被服裝設(shè)計者和制造商實際使用，它必須提高模擬服裝真實表現(xiàn)的功能。Dedicated 3DCAD for garment modellingAbstractWhile considerable progress has been made in fabric modelling techniques, which could be used in garment computer aided

38、 design(CAD) systems, less attention has been paid to the way in which garments might be specified in a CAD system. The final shape taken by a garment is often achieved through the incorporation of darts, seams, edges, stiffening pads and local stretch of the fabric. In order to gain credibility,CAD

39、 systems should have to functionally handle the level of complexity normally found in garment assemblies combined with a simple interface to specify the constructional detail. Different conceptual approaches are possible. Given an accurate drape algorithm,garment block patterns in a chosen fabric co

40、uld simply be anchored or attached around the mannequin in order to achieve avisualisation of a garment. If changes were necessary, the user would alter the 2D patterns and re-run the visualisation. An alternative and possibly more productive approach would be to specify in 3D, with advanced drawing

41、 tools, the 3D shape required. Processing of the 3D garment piece using expert rules would indicate the 2D shape and constructional detail required to achieve the final form. This paper describes a CAD system that is under development and which aims to facilitate both the approaches. Keywords: CAD;

42、Garment design; Flattening; Draping1. IntroductionComputer aided design (CAD) is now an established technique for generating practical designs for most engineering applications. Early systems were simply a replacement for drafting boards and drawing tools. However, modern CAD systems incorporate man

43、y analysis tools to assist designers in optimising designs or testing the functionality of their designs. In addition, manufacturing information can be generated efficiently fromCAD designs.The development of computer systems to aid the manufacture of garments has been rather piece meal to date.Desi

44、gn systems have concentrated on the visualisation of garments and the need to efficiently create an image of a design.Such systems have proven very effective with companies who manufacture garments for large retail organisations where volumes arelarge and designs have to be vetted by buyers from the

45、retailer. The ability to quickly try different colours and textures is invaluable in such circumstances. Also, such systems are capable of generating prototype textile prints using the latest printer technology. In addition, there is a high degree of automation available in subsequent manufacturing

46、processes which nest 2D patterns and generate cutter head path information for large cutting tables.There remain three areas where computer assistance has met with little or no success.1. The 3D specification of a complete garment.2. The creation of 2D patterns.3. Accurate simulation of garment visu

47、alisation sensitive to fabric type and constructional detail.The lack of development in these areas has resulted in the inability of companies to truly adopt a computer integrated approach to design and manufacture. The purpose of the work described here is to offer a possible configuration for such

48、 an integrated approach. This will highlight the impact as regards the user interface and identify the core technologies required to promote this integration.2. The present situation and limitationsThe present situation for most garment manufacturing companies which produce medium to large batches c

49、an be described by Fig. 1. Designers originate designs based on their own creativity subject to current fashion trend sand the target market. Their design specification is usually in the form of a paper drawing representing a visualisation of the garment.Sometimes attached to this drawing may be a s

50、mall sample or swatch ofthe fabric fromwhich thegarment is to be made.Itis importanttonote that designs in this form are not regarded as either a full garment constructional specification or an exact 2D view of the 3D garment product.Consequently, this means of communicating designs tends to be info

51、rmal but sufficiently detailed for the next manufacturing stage to proceed. The major limitations of this situation are twofold.1. The subjective nature of how the pattern technologist interprets the designs to produce the actual 2D patterns. 2. Secondly, the low acceptance rates that are achieved a

52、t the assessment stage.This results in not only a large number of rejected samples but also,more importantly,lost time and diversion of effort.3. Computer integrated approachThe approach proposed here is presented in Fig. 2. This block diagram depicts the core elements required for an integrated app

53、roach. The key elements which have prevented such an integrated approach from being adopted to date arean effective design interface for designers to create 3D specifications of garments; a robust pattern flattening module;an accurate drape engine.For an integrated manufacturing approach to be succe

54、ssful, all three of these difficult elements must be adequately accomplished. These elements will now be considered inmore detail.3.1. Design interfacemannequin. Such surface descriptions must be capable of specification using existing mathematical techniques using a suitable interface. However, it

55、would be inappropriate for a designer to describe the 3D geometry taken up by areas of the garment where the fabric drapes. Current CAD systems would certainly be able to accurately represent these draped shapes using techniques such as the many forms of bicubic surfaces 1, but it would be unreasona

56、ble to expect a designer to tediously specify such shapes.Secondly,in order to accurately predict or visualise the shape taken up by thegarment, the designer would have to have a very comprehensive knowledge of the fabric behaviour.For the purposes of the design interface, it is proposed that repres

57、entations such as that shown in Fig. 3(a) would be acceptable for initial garment specification asa stylised formwhich would be capable of incorporating all of the constructional detail necessary for manufacture.While notbeingan attempt toaccurately simulatethe 3D appearance of the garment at this point, the design interface should embody functionality to implicitly define all other aspects of the garment speci