Parallelized Incomplete Poisson Preconditioner in Cloth Simulation

Efficient cloth simulation is an important problem for interactive applications that involve virtual humans, such as computer games. A common aspect of many methods that have been developed to simulate cloth is a linear system of equations, which is commonly solved using conjugate gradient or multi-grid approaches. In this paper, we introduce to the computer gaming community a recently proposed preconditioner, the incomplete Poisson preconditioner, for conjugate gradient solvers. We show that the parallelized incomplete Poisson preconditioner (PIPP) performs as well as the current state-of-the-art preconditioners, while being much more amenable to standard thread-level parallelism. We demonstrate our results on an 8-core Apple* Mac* Pro and a 32-core code name Emerald Ridge system

Elastic Context: Encoding Elasticity for Data-driven Models of Textiles

Physical interaction with textiles, such as assistive dressing, relies on advanced dextreous capabilities. The underlying complexity in textile behavior when being pulled and stretched, is due to both the yarn material properties and the textile construction technique. Today, there are no commonly adopted and annotated datasets on which the various interaction or property identification methods are assessed. One important property that affects the interaction is material elasticity that results from both the yarn material and construction technique: these two are intertwined and, if not known a-priori, almost impossible to identify through sensing commonly available on robotic platforms. We introduce Elastic Context (EC), a concept that integrates various properties that affect elastic behavior, to enable a more effective physical interaction with textiles. The definition of EC relies on stress/strain curves commonly used in textile engineering, which we reformulated for robotic applications. We employ EC using Graph Neural Network (GNN) to learn generalized elastic behaviors of textiles. Furthermore, we explore the effect the dimension of the EC has on accurate force modeling of non-linear real-world elastic behaviors, highlighting the challenges of current robotic setups to sense textile properties

Incorporación de fuerzas de presión al modelado de cuerpos blandos

Se presenta un sistema de manejo de objetos flexibles 3D basado en leyes físicas, con fin de realizar diversas técnicas de modelado interactivo, a partir de una interfaz 2D. Se utiliza como motor un sistema de Mass-Spring-Damper extendido, con la incorporación de una fuerza interna adicional para representar el comportamiento de objetos de materiales blandos; el modelado puede desenvolverse ya sea aplicando fuerzas externas como controlando la interna, este método es lo suficientemente simple para dar buenos resultados en tiempos interactivosIII Workshop de Computación Gráfica, Imágenes y Visualización (WCGIV)Red de Universidades con Carreras en Informática (RedUNCI

Incorporación de fuerzas de presión al modelado de cuerpos blandos

Se presenta un sistema de manejo de objetos flexibles 3D basado en leyes físicas, con fin de realizar diversas técnicas de modelado interactivo, a partir de una interfaz 2D. Se utiliza como motor un sistema de Mass-Spring-Damper extendido, con la incorporación de una fuerza interna adicional para representar el comportamiento de objetos de materiales blandos; el modelado puede desenvolverse ya sea aplicando fuerzas externas como controlando la interna, este método es lo suficientemente simple para dar buenos resultados en tiempos interactivosIII Workshop de Computación Gráfica, Imágenes y Visualización (WCGIV)Red de Universidades con Carreras en Informática (RedUNCI

Modeling and estimation of internal friction in cloth

Force-deformation measurements of cloth exhibit significant hysteresis, and many researchers have identified internal friction as the source of this effect. However, it has not been incorporated into computer animation models of cloth. In this paper, we propose a model of internal friction based on an augmented reparameterization of Dahl's model, and we show that this model provides a good match to several important features of cloth hysteresis even with a minimal set of parameters. We also propose novel parameter estimation procedures that are based on simple and inexpensive setups and need only sparse data, as opposed to the complex hardware and dense data acquisition of previous methods. Finally, we provide an algorithm for the efficient simulation of internal friction, and we demonstrate it on simulation examples that show disparate behavior with and without internal friction

Textile Forms’ Computer Simulation Techniques

Computer simulation techniques of textile forms already represent an important tool for textile and garment designers, since they offer numerous advantages, such as quick and simple introduction of changes while developing a model in comparison with conventional techniques. Therefore, the modeling and simulation of textile forms will always be an important issue and challenge for the researchers, since close‐to‐reality models are essential for understanding the performance and behavior of textile materials. This chapter deals with computer simulation of different textile forms. In the introductory part, it reviews the development of complex modeling and simulation techniques related to different textile forms. The main part of the chapter focuses on study of the fabric and fused panel drape by using the finite element method and on development of some representative textile forms, above all, on functional and protective clothing for persons who are sitting during performing different activities. Computer simulation techniques and scanned 3D body models in a sitting posture are used for this purpose. Engineering approaches to textile forms’ design for particular purposes, presented in this chapter, show benefits and limitations of specific 3D body scanning and computer simulation techniques and outline the future research challenges

A Mathematical Modeling Framework for Analysis of Functional Clothing

In the analysis and design of functional clothing systems, it is helpful to quantify the effects of a system on a wearer’s physical performance capabilities. Toward this end, a clothing modeling framework for quantifying the mechanical interactions between a given clothing system design and a specific wearer performing defined physical tasks is proposed. The modeling framework consists of three interacting modules: (1) a macroscale fabric mechanics/dynamics model; (2) a collision detection and contact correction module; and (3) a human motion module. In the proposed framework, the macroscopic fabric model is based on a rigorous large deformation continuum-degenerated shell theory representation. Material models that capture the stress-strain behavior of different clothing fabrics are used in the continuum shell framework. The collision and contact module enforces the impenetrability constraint between the fabric and human body and computes the associated contact forces between the two. The human body is represented in the current framework as an assemblage of overlapping ellipsoids that undergo rigid body motions consistent with human motions while performing actions such as walking, running, or jumping. The transient rigid body motions of each ellipsoidal body segment in time are determined using motion capture technology. The integrated modeling framework is then exercised to quantify the resistance that the clothing exerts on the wearer during the specific activities under consideration. Current results from the framework are presented and its intended applications are discussed along with some of the key challenges remaining in clothing system modeling