bringing clothing animation to the entertainment industry, textile mechanics and engineering applications, and the latest in apparel. CAD software and ...
Can We Get There From Here?: Current Challenges in Cloth Design, Modeling and Animation Organizer Dr. David E. Breen (California Institute of Technology) Panelists Jeffrey W. Eischen (North Carolina State University) Michael Kass (Pixar) Nadia Magnenat Thalmann (University of Geneva) Maurizio Vecchione (ModaCAD Inc.) Summary This panel will address the technical, economic and marketing hurdles that inhibit the widespread use of cloth/clothing modeling, design and animation technology. Many of the fundamental technologies needed to support cloth modeling have already been developed. Still, we do not see computer-animated characters wearing realistic clothing, and clothing designers are not creating new fashions with computer-based 3-D design systems. The CAD industry is capable of providing the systems for designing the Boeing 777, but almost none of the clothing we wear is designed with 3-D CAD tools. The panel will explore the reasons that the design of cloth and clothing, a material that has been a part of the human experience for thousands of years, has not yet been fully computerized. A variety of issues related to cloth/clothing modeling will be explored. Are there fundamental technological barriers preventing us from fully deploying computer technology when modeling, designing, or animating cloth/clothing? Have the technical problems been solved and our computers are just not fast enough? Do we simply need good user interfaces to solve this difficult modeling problem? Is realism always important when modeling cloth? Does computer-based manufacturing place special demands on cloth modeling? Are designers, artists and clothing makers resisting the computerization of their “black art”? Can the average user even afford to do cloth modeling? Is the technology too expensive? These are some of the questions that the panelists will address. Before describing the challenges involved in modeling and animating clothing, the panelists will provide a snapshot of the state-of-the-art in the field. Topics will include the detailed modeling of cloth, the research involved in clothing virtual actors, bringing clothing animation to the entertainment industry, textile mechanics and engineering applications, and the latest in apparel CAD software and technology. Each speaker will briefly describe their work in the field, augmenting their talks with images, animations and live demonstrations. The panel will strive to achieve several goals. It will highlight cloth/clothing modeling as a separate field of study. Very often cloth modeling is seen as simply another application of deformable models. Cloth is a unique material with unusual properties that requires new and different modeling methods. In the CAD field, software systems for designing clothing are certainly different from conventional CAD systems that model collections of rigid parts. Given the unique nature of the field, it is important to seed the SIGGRAPH community with new ideas and challenges. The panel will educate the audience in a way that stimulates future research in cloth/clothing modeling. Another goal of the panel is to expose the SIGGRAPH community to those people working in the field of cloth/clothing modeling who are interested in more than just visual effects. The panel includes speakers who have a broader view of cloth modeling, including
those working within the textile engineering and CAD communities. They are more concerned with accurately modeling cloth as an engineering material and bringing powerful CAD tools to the marketplace than the making of pretty pictures. The panel also consists of an international participant, in recognition that some of the best clothing modeling research is being conducted overseas. David E. Breen My main interest in cloth modeling has focused on accurately capturing and modeling the unique mechanical properties and behavior of woven cloth. When modeling cloth, it is customary to assume that cloth is simply a special kind of continuous deformable sheet. In fact, cloth is a complex mechanical structure. I believe that conventional computer graphics continuum models are inadequate for accurately simulating the mechanical behavior of woven cloth. My research has addressed this inadequacy in two ways. First, I have developed a microstructural model of cloth which directly represents the important low-level features of cloth, namely the thread crossing. Second, I have developed methods for incorporating non-linear mechanical empirical data into my model. This removes the need to make the assumption of linearity when defining the model, and produces a model that more accurately represents woven cloth. My talk will briefly describe my novel approach to modeling cloth. Images and animations will be used to present my research results. When modeling cloth, I will discuss what I think it takes to “get it right”. All of the details of my microstructural approach have not been worked out, though. Many components of the approach are still not fully developed. I will described these unfinished components that, when completed, will make my model fast and dynamic, as well as, accurate.
Jeffrey W. Eischen My talk will focus on the physical aspects of cloth modeling. A brief review of the work which properly accounts for the mechanical properties of cloth will be presented. The difficulties encountered when attempting to realistically model cloth will also be presented. The various applications of such computer modeling will be discussed: modeling of cloth on the human body (static and dynamic), modeling of cloth on inanimate
objects such as furniture and automobiles, modeling of cloth during manufacturing operations such as: cutting, picking, placing, folding, sewing, etc. Michael Kass The rigors of computer-graphics production place severe demands on physically-based computer graphics techniques. They must be fast, stable, and predictable. But above all, the techniques must be controllable if they are to be useful in storytelling. In this talk, I will discuss some of the issues in bringing such techniques for cloth modeling and animation into the environment of an animation studio. In studio animation, absolute realism is not necessarily the goal, even in a seemingly realistic piece; there may be a great deal of exaggeration for a desired effect. Nonetheless, physical simulation, perhaps with exaggerated parameters, offers the opportunity to achieve a level of complexity in clothing animation that is difficult or impossible to achieve with traditional techniques. The clothing animation in Toy Story was done without simulation, and became so tedious that the animators were unable to achieve the level of quality they hoped for. Since then, we have developed tools for the physically-based simulation of cloth. I will describe our experience with these tools, and with the process of melding clothing simulation into our production environment.
design. “Did you realize that 70% of today’s apparel is partially designed on computers? What are the limits of today’s Computer Based Apparel Design? Why is 2-D king and the industry does not want to accept 3-D design technology?” A discussion of the industry’s trends and needs, and a review of the elements making up realistic cloth simulation with special discussion of the emerging rendering and modeling techniques specifically focused to amorphous materials behaviors will also be included. Cloth-like surface detail may also be added by deploying special rendering techniques without complicating the model itself. I will show how. Additional topics will include new rendering approaches to the problems of textile simulations with a special discussion of the unique problems associated with texture mapping textiles and the importance of proper control over UV parameters. The talk will close with the presentation of major directions of future expansion and major challenges driven by the industry, including the emergence of knowledge-based technologies for cloth simulation. I plan to show live demos and examples, and will take an industry approach, combining the technical approaches with the business forces motivating the realization of certain technical options.
Nadia Magnenat Thalmann It is a far cry from simulating a flag, or draping a rectangular cloth on a table, to the animation of clothed virtual humans. First, garment cloth tends to be of rather complex form, so that modeling it as a deformable surface requires consideration of many component elements, greatly augmenting computation time. Second, collisions with the environment (the body, other clothing) must be analyzed when determining the shape of the garment as it is worn and changes during animation. We present a selection of work on simulated clothing, one of our major research areas as early as 1988. First we show our remake of a scene from “The Seven Year Itch”, in which a virtual Marilyn holds down her skirt against the air current from a subway vent. Then we discuss technical issues involved in decreasing the calculation time, illustrated by our film of Marilyn receiving the Golden Camera Award in Berlin (l996), in the simulation of armored costumes for the terra cotta soldiers from Xian, and using VLNET (Virtual Life System) for the collaborative interactive design of a virtual dress.
Maurizio Vecchione In my talk I will present a brief review of the current state of graphical design technology applied to the textile/apparel industry with special focus on the technologies deployed for apparel
Fabrics designed, modeled and rendered onto a lifelike model photorealistically in ModaCAD.
Relevant URLs
Bibliography
A summary of Breen’s Ph.D. work on cloth models.
M. Aono, P. Denti, D.E. Breen and M. Wozny, “Fitting a Woven Cloth Model to a Curved Surface: Dart Insertion,” IEEE Computer Graphics and Applications, Vol. 16, No. 5, pp. 60-70, September 1996.
www.gg.caltech.edu/~david/david_pbm.html
The abstracts for IEEE CG&A’s special issue on Computer Graphics in Textiles and Apparel, an issue guest-edited by Breen. www.computer.org/pubs/cg%26a/ backissu.htm#september1996
National Textile Center Home Page Eischen is part of NTC, a university consortium exploring textile-related technologies.
D.H. House, R.W. DeVaul and D.E. Breen, “Towards Simulating Cloth Dynamics Using Interacting Particles,” International Journal of Clothing Science and Technology, Vol. 8, No. 3, pp. 75-94, 1996. D.E. Breen, D.H. House and M.J. Wozny, “Predicting the Drape of Woven Cloth Using Interacting Particles,” SIGGRAPH ‘94 Conference Proceedings, (Orlando, FL, July 1994) pp. 365-372.
ntc.tx.ncsu.edu/ntc.html
Computer-Aided Engineering and Mechantronics in the Design of Apparel Systems A report on an NTC project. ntc.tx.ncsu.edu/html/REPORTS/ SUMMER-FOLDER/l.html
A summary of past and present cloth animation research supervised by Magnenat Thalmann. miralabwww.unige.ch/Research/Research_areas/ Rcloth.html
ModaCAD Home Page An overview of the apparel and textile CAD products offered by Vecchione’s company. ns.sip.net/modacad/home.html
J. Eischen, S. Deng and T.G. Clapp, “Finite Element Modeling and Control of Flexible Fabric Parts,” IEEE Computer Graphics and Applications, Vol. 16, No. 5, pp. 71-80, September 1996. J. Eischen, S.D. McWaters and T.G. Clapp, “Computer Simulation of Fabric Deformation for the Design of Equipment,” International Journal of Clothing Science and Technology, Vol. 6, No. 5, 1994. J. Eischen and T. McDevitt, “Simulation of Fabric Draping and Manipulation with Arbitrary Contact Surfaces and Adaptive Meshing,” Proceedings of the 4th Annual Academic Apparel Research Conference, Raleigh, NC, February 1993. P. Volino, N. Magnenat Thalmann, S. Jianhua and D. Thalmann, “An Evolving System for Simulating Clothes on Virtual Actors,” IEEE Computer Graphics and Applications, Vol. 16, No. 5, pp. 42-51, September 1996. P. Volino, M. Courchesne, N. Magnenat-Thalmann, “Versatile and Efficient Techniques for Simulating Cloth and Other Deformable Objects,” SIGGRAPH ‘95 Conference Proceedings, (Los Angeles, August 1995) pp. 137-144. M. Carignan, Y. Yang, N. Magnenat Thalmann, D. Thalmann, “Dressing Animated Synthetic Actors with Complex Clothes,” Computer Graphics (Proc. SIGGRAPH ‘92), Vol. 26, No. 2, pp. 99-104, July 1992. J.W.S. Hearle, “Virtual Reality and Fabric Mechanics (Part I),” Textile Horizons, Vol. 15, No. 2, pp. 12-17, April 1995. J.W.S. Hearle, “Virtual Reality and Fabric Mechanics (Part II),” Textile Horizons, Vol. 15, No. 3, pp. 10-14, June 1995. H.N. Ng and R.L. Grimsdale, “Computer Graphics Techniques for Modeling Cloth,” IEEE Computer Graphics and Applications, Vol. 16, No. 5, pp. 28-41, September 1996.
