通用三维服装模型的强约束动态仿真方法

随着三维游戏和虚拟试衣要求的不断提高,服装仿真已经从布料模拟向服装动态模拟的方向发展,具有真实性、实时性、通用性与交互性的服装仿真技术有很强的研究和实用价值。针对目前算法研究中普遍存在的实时性与通用性不足,提出了一种针对任意三维服装模型的实时仿真方法,将模型顶点和三角面映射为质点的弹簧模型,以克服传统的布料解算器对三维模型的网格限制。利用简便易行的Verlet积分器提高运算效率,并对质点间的形变进行强约束补偿,防止过拉伸(超弹)现象的发生,提高了系统的稳定性。通过实验验证了算法的高效性和可靠性,并可方便地以插件或模块形式与其它软件整合。     

3D virtual apparel design for industrial applications

The integration of physics-based models within CAD systems for garment design leads to highly accurate cloth shape results for virtual prototyping and quality evaluation tasks. To this aim, we present a physics-based system for virtual cloth design and simulation expressly conceived for design purposes. This environment should allow the designer to validate her/his style and design option through the analysis of garment virtual prototypes and simulation results in order to reduce the number and role of physical prototypes. Garment shapes are accurately predicted by including material properties and external interactions through a particle-based cloth model embedded in constrained Newtonian dynamics with collision management, extended to complex-shaped assembled and finished garments. Our model is incorporated within a 3D graphical environment, and includes operators monitoring the whole design process of apparel, e.g. panel sewing, button/dart insertion, multi-layered fabric composition, garment finishings, etc. Applications and case studies are considered, with analysis of CAD modelling phases and simulation results concerning several male and female garments.     

基于服装款式平面图的三维款式效果显示研究

本文介绍了由服装的款式平面图研究三维款式效果显示的途径,提出了一种非传统的实现三维着装效果显示的方法,即在款式平面图的基础上,结合标准人台的三维数据点,增加适当的服装空隙量来获取款式三维造型点并构造服装曲面,为服装的款式设计提供更直观的帮助。     

基于ADAMS的弧焊机器人运动仿真

机器人三维运动仿真是当前机器人研究领域中重要的研究方向之一。采用CAD软件Pro/E和机械系统动力学仿真软件ADAMS,对德国CLOOS公司生产的76AW型弧焊机器人建立了三维运动仿真模型。采用Denavit-Hartenberg方法建立了连杆坐标系下的机器人运动学模型,并采用Matlab编写了运动学正、逆解的程序。详细阐述了模型的建立方法及具体过程,实现了在ADAMS环境下的机器人焊缝路径的运动仿真。为机器人动力学及离线编程技术的研究提供了基础。     

A new design concept: 3D to 2D textile pattern design for garments

‘The word “fashion” is synonymous with the word “change”. Fashion begins with fabrics and fabrics begin with colour’. This famous remark/definition of ‘fashion’ must now be revised in the era of digital technology. In this paper, we propose a novel print design concept, from 3D garments to 2D textiles. By taking advantage of the cutting-edge developments in surface parameterisation, cloth simulation and texture assignment, we develop a computer system that allows designers to create figure-flattering prints directly onto 3D garments, and will output 2D pattern pieces with matched texture that are ready for digital printing and garment production. It reverses the traditional design process from 2D fabrics to 3D garments. The results produced by the proposed method guarantee textural continuity in both garment and pattern pieces. It not only releases apparel makers from the tedious work of matching texture along seams, but also provides users with a new tool to create one-of-a-kind fashion products by designing personalised prints.     

基于质点-弹簧模型碰撞检测算法的改进

碰撞检测技术在织物的模拟等方面中有着广泛的应用.在采用质点-弹簧模型对柔性表面进行建模,对网格曲面进行三角划分后,为环境中的物体建立各自的方向包围盒(OBB).用改进的碰撞检测和自碰撞检测算法对柔性织物及其所处三维空间中的物体进行处理,提高了柔性织物动态仿真的速度.     

LIY: learn-it-yourself software interfaces

An increasing number of people are becoming users of unfamiliar software. They can be genuinely "new" computer users or part of a growing group who are transferring skills and knowledge from a familiar product such as a word processor to a functionally similar, but different, unfamiliar one. The problem for users in this position is that they do not have access to training courses to teach them how to use such software and are usually forced to rely on text-based documentation. LIY is a method for producing computer-based tutorials to teach the user ofasoftware product.This paper describes how LIY is, in turn, (1) a method for application system design which recognizes the need for tutorial design (a task analysis and user interface specification provide information structures that are passed to the tutorial designer); (2) a support environment for the tutorial designer (in addition to prompting for courseware for nodes in the task analysis, LIY provides a ready-made rule base for constraining the degree of learner control available while the tutorial is in use. The designer is able to tailor this rule base for a specific tutorial); and (3) a tutorial delivery environment (the tutorial adapts to individual learners and offers a degree of learner control).     

基于弹簧质点模型的二维/三维映射算法*

提出了一种用于服装设计的二维/三维映射算法.该算法基于弹簧质点变形模型,服装裁剪片二维到三维映射及三维到二维映射可以在该模型中得到统一的实现.在服装裁剪片二维到三维的映射过程中,二维裁剪片被放置在人体模型附近的初始位置,在缝合力的作用下,裁剪片自动变形并缝合到人体模型上.在服装裁剪片三维到二维映射的过程中,三维裁剪片被初始映射到指定的平面内,在弹性变形力的作用下,逐步变形并得到最终的二维裁剪片.在进行服装裁剪片二维到三维映射的过程中,考虑了干涉检验的问题.     

基于弹簧质点模型的布料仿真及碰撞处理方法

该文对布料仿真方法进行了研究。首先运用弹簧——质点系统建立布料的面模型，将柔性布料离散为分布均匀的质点，进而对整个系统进行了动力学分析。为获得高效的算法，采用了显式欧拉方法对微分方程进行数值积分。碰撞问题是布料仿真研究中的重要内容，该文针对具体碰撞对象设计了高效的碰撞检测方法，采用二分法作为碰撞响应算法，最后进行了布料产生碰撞后趋于稳定及滑落的动态仿真演示。该方法在达到较高计算效率的基础上，确保了仿真系统的稳定性。     

Interactive virtual try-on clothing design systems

Clothing computer design systems include three integrated parts: garment pattern design in 2D/3D, virtual try-on and realistic clothing simulation. Some important results have been obtained in pattern design and clothing simulation since the 1980s. However, in the area of virtual try-on, only limited methods have been proposed which are applicable to some defined garment styles or under restrictive sewing assumptions. This paper presents a series of new techniques from virtually sewing up complex garment patterns on human models to visualizing design effects through physical-based real-time simulation. We first employ an hierarchy of ellipsoids to approximate human models in which the bounding ellipsoids are optimized recursively. We also present a new scheme for including contact friction and resolving collisions. Four types of user interactive operation are introduced to manipulate cloth patterns for pre-positioning, virtual sewing and later obtaining cloth simulation. In the cloth simulation, we propose a simplified cloth dynamic model and an integration scheme to realize a high quality real-time cloth simulation. We demonstrate the robustness of our proposed systems by complex garment style virtual try-on and cloth simulation.     

基于声线跟踪法开发超声无损检测动态仿真软件

以“声线跟踪法”为基础，运用面向对象的编程语言VisualC＋＋和三维场景开发工具OpenGL，按照面向对象的程序设计思想开发了超声波无损检测仿真软件。该系统实现了超声检测过程的三维可视化并对超声波传播路径和A型显示进行了较为准确的模拟。该文对仿真过程中的三维介质建模和传播路径模拟计算等关键问题进行了详细的讨论，采用CSG／B-Rep混合模型表示法对三维介质模型进行快速建模，并且采用声线跟踪法对传播路径进行较为准确的模拟。最后通过仿真实例，验证了算法的有效性。     

MOSBY: a molecular structure viewer program with portability and extensibility

A molecular structure viewer program, MOSBY has been developed for studies that use atomic coordinates to understand the structures of protein molecules. The program is designed to be portable with a comprehensive user interface by our high-throughput graphics library. In addition, it cooperates with extension modules customized for individual research topics and analysis. For example, an electron density module loads and displays electron density maps derived in X-ray crystallographic analysis superimposed to an atomic model. A molecular dynamics module reads a trajectory file of the results of molecular dynamics calculations and animates the structure. These plug-in modules are devised to function without modification to the MOSBY program. For variations of analysis and calculations with atomic coordinates, the portability and extensibility illustrated by MOSBY play an important rule in scientific computational tools with active software development.     

三维服装仿真中的"服装-人体"快速冲突检测及响应算法

维胆装仿真可以为三维人体动画生成逼真的服装动态效果，但其中的冲突检测与仿真计算的时间复杂度太高，其实用性一直受到很大限制．提出了一种快速的“服装-人体”冲突检测友响应算法，在人体运动状态下，快速检测服装与人体之间的位置冲突，其时间复杂度仅为O（n）（n为服装模型上的顶点数目）．在此基础上，提出一种合理有效的冲突响应机制，并实现快速稳定的三维服装仿真，取得了真实的仿真结果．     

面向智能制造加工的虚拟调试系统开发与应用

为了解决智能制造加工系统的调试成本高、周期长及风险大等问题,研究了面向智能制造加工的虚拟调试技术。以智能制造加工系统中机器人、PLC、数控车床及加工中心为研究对象,首先通过工业以太网进行组网并与PC机进行通讯,基于OSGI.NET插件框架开发了交互控制软件,将每个设备驱动做成插件,使得每个插件能够实现当前设备的数据采集、监控及控制。并且在RoboDK软件中建立了系统虚拟的3D模型,通过Redis数据库实现了控制设备和虚拟模型之间的信号交互。然后使用了PLC、机器人控制器、数控车床及加工中心控制器对系统3D模型进行虚拟调试,最后通过实验验证了加工系统的有效性。     

SOFTWARE PROCESS FLIGHT SIMULATION Dynamic Modeling Tools and Metrics

Process flight simulation tools can help managers understand the dynamics of new processes and technologies before they are introduced. This article tells how these exploratory tools can be used for IS project management, simple modeling of the software process, and modeling the dynamics of the IS organization in transition.     

Computer-aided ergonomics: a case study of incorporating ergonomics analyses into workplace design

One of the primary goals of computer-aided ergonomics is to develop software tools that allow ergonomics information to be accessed at the earliest stages of design. This case study discusses a PC-based software program that allows a designer to quantify a worker's biomechanical risk for injury based on a proposed workplace design. The program couples an established software tool for biomechanical analysis, the Three-Dimensional Static Strength Prediction Program (3DSSPP), with a widely used computer-aided design software package, AutoCAD. The use of this "3DSSPP/AutoCAD interface" in the proactive analysis of an automotive assembly task is described and the results compared with an independent assessment using observations of workers performing the same task. Both studies yield similar conclusions, suggesting that proactive use of software such as the 3DSSPP/AutoCAD interface may be a valid tool in evaluating proposed workplace designs. In this context, issues in the analysis of workplace designs regarding the use of supporting ergonomic tools, assumptions, and posture selection are discussed.     

Designing Personalized Garments with Body Movement

The standardized sizes used in the garment industry do not cover the range of individual differences in body shape for most people, leading to ill-fitting clothes, high return rates and overproduction. Recent research efforts in both industry and academia, therefore, focus on virtual try-on and on-demand fabrication of individually fitting garments. We propose an interactive design tool for creating custom-fit garments based on 3D body scans of the intended wearer. Our method explicitly incorporates transitions between various body poses to ensure a better fit and freedom of movement. The core of our method focuses on tools to create a 3D garment shape directly on an avatar without an underlying sewing pattern, and on the adjustment of that garment's rest shape while interpolating and moving through the different input poses. We alternate between cloth simulation and rest shape adjustment based on stretch to achieve the final shape of the garment. At any step in the real-time process, we allow for interactive changes to the garment. Once the garment shape is finalized for production, established techniques can be used to parameterize it into a 2D sewing pattern or transform it into a knitting pattern.     

TiGenerator: Object-based training image generator

A plug-in, TiGenerator, is written for the open source software SGeMS to generate 3D, categorical training images. It provides a graphical user interface to generate various parametric as well as non-parametric shapes using unconditional Boolean simulation with interaction between the objects. The code design allows new shapes and features to be added easily without altering the main algorithm.     

融合QPSO算法的多精度布料仿真建模方法

在布料建模领域，如何快速模拟布料形变之后的褶皱细节是研究的热点。通过使用多精度布料建模方法，在布料的不同形变区域使用不同精度的网格，可以有效平衡建模的精度和速度，已有的工作主要是在布料形变过程中，动态计算出布料质点邻域的曲率，依据人为设定的阈值，划分出布料的多精度区域，而在大部分场景中，布料的变形模式没有规律，固定不变的阈值可能会影响布料的仿真效果。针对该问题，首先将基于量子行为的粒子群算法引入建模过程，通过粒子群算法对布料表面的搜索，提高了布料弯曲部位的搜索效率，优化了多精度布料的建模速度和精度，其次针对布料仿真运动过程进行研究，参考布料受空气阻力的数学模型，以及粒子动力学中的数值积分方法，优化布料运动的仿真计算方法。实验证明，与现有布料多精度方法相比，该方法能较快检测到布料褶皱区域并判断是否需要细化，且能较好地表现出布料仿真过程中空气阻力对布料造成的形变。     

基于Mechanism/Pro的汽车悬架系统运动仿真

为了解决多体动力学分析仿真过程中困扰仿真人员的模型建立和修改问题,以汽车独立悬架为研究对象,提出机械系统仿真一种比较理想的方法.首先应用多体动力学求解理论,从悬架物理模型中提取多体动力学求解模型.针对ADAMS/View建模能力较弱,通过三维建模软件Pro/E建模,采用Mechanism/Pro模块定义刚体、添加约束和驱动、调用ADAMS/Solver求解.可以很方便地建立复杂机械系统模型,并根据仿真结果及时对模型进行修改,实现机械系统多体动力学仿真的前处理、求解以及后处理均集成在Pro/E环境中.