SGER: Combined Micro- and Macro-Model for Simulating Cloth by Deriving Mechanical Behavior from Underlying Fabric Structure

SGER：通过从底层织物结构导出机械行为来模拟布料的微观和宏观组合模型

• 批准号: 0407963
• 负责人: Brian Barsky
• 金额: $ 7.5万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-05-01 至 2006-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0407963&HistoricalAwards=false
• 关键词: SGER; Combined; Micro; Macro; Model

Great strides have been made in computer animation and special effects. In some cases, synthetic or virtual actors have been integrated into live action films. This raises the need to accurately model and render clothing. In addition, increases in automation in the garment industry create a need for more sophisticated design and manufacturing techniques, which in turn require research in cloth modeling. This investigation will bring a more rigorous basis for cloth modeling to computer graphics, and will have the added benefit of being of interest to the garment industry.This research will create a cohesive environment for designing fabrics for garments through a two-stage system. The first stage will determine the essential properties of cloth from its underlying structure and then the second stage will use a tailored model of the specific fabric to realistically simulate the dynamic behavior of a garment. The first stage, the micro-model, will simulate the deformation of the yarns in a small section of cloth and will analyze the results of subjecting the sample to various loading conditions. The relations describing the deformation behavior of cloth as a continuum will then be used in the second stage, the macro-model, to animate a full garment. The first stage micro-model will be more general than the specific setups currently used in textile research. In particular, the proposed model will consider yarns with arbitrary yarn paths that have twist and sliding contacts with friction. Empirical evidence and observation of woven fabrics have shown that the latter two features have a substantial role in the overall look and behavior of cloth, but neither has been considered in any previous work in textiles or computer graphics for modeling yarns in fabrics. A related issue is how to deal with the contacts, since the yarns will be in close proximity almost everywhere, contributing to traction forces. The second stage will simulate fabric using the revamped model based on the results of the first stage. The main focus will be on the constitutive equations and incorporating coupled nonlinear behavior. Features such as permanent wrinkles will be added in a later pass. Additional enhancements include local reflectance, transparency, and wind resistance as a function of the local strain. The actual relations would be derived during the first stage but then used during rendering or computation of external forces in this macro-model simulation.

在计算机动画和特效方面已经取得了长足的进步。在某些情况下，合成演员或虚拟演员已经被融入到真人电影中。这就提高了对服装进行精确建模和渲染的需求。此外，服装业自动化程度的提高导致了对更复杂的设计和制造技术的需求，这反过来又需要对布料建模进行研究。这项研究将为计算机图形学带来更严格的布料建模基础，并将对服装行业产生额外的好处。这项研究将通过两个阶段的系统为服装面料设计创造一个连贯的环境。第一阶段将根据底层结构确定布料的基本属性，第二阶段将使用特定布料的定制模型来逼真地模拟服装的动态行为。第一阶段，微观模型，将模拟纱线在一小段布料中的变形，并将分析样品在不同加载条件下的结果。将布料的变形行为描述为连续统一体的关系随后将用于第二阶段，即宏模型，以设置完整服装的动画。第一阶段的微观模型将比目前在纺织研究中使用的特定设置更通用。特别是，所提出的模型将考虑具有任意纱线路径的纱线，这些纱线具有与摩擦的扭曲和滑动接触。经验证据和对机织织物的观察表明，后两个特征对织物的整体外观和行为有很大的影响，但这两个特征在以往的任何纺织工作中都没有考虑过，也没有考虑过用于建模织物中的纱线的计算机图形学。一个相关的问题是如何处理接触，因为纱线几乎在任何地方都很接近，从而产生牵引力。第二阶段将根据第一阶段的结果，使用改进的模型来模拟织物。主要的焦点将放在本构方程和包含耦合的非线性行为上。像永久性皱纹这样的特征将在以后的过程中添加。其他增强功能包括局部反射率、透明度和随局部应变变化的风阻。在此宏模型模拟中，实际关系将在第一阶段得到，但随后在渲染或计算外力时使用。