Garment creation continues to be the most tedious part of the virtual clothing process. In this paper, we present an easy to use sketch-based cloth modeling approach. Contours can be easily sketched on a mannequin to generate quad meshes to represent pieces of cloth already fitted and draped. Typically, the clothing process depends greatly on the meshing scheme that has to infer its geometry from the input boundary. Our quad meshing scheme is based on discrete Coons patches but with arbitrary boundary input. We also apply the permanence principle to our topological solution to allow more control over the influence of the input boundary polyline on the interior output polygonal mesh. This facilitates the creation of folds that are strongest in curvature at the boundary and which diminish towards the interior. The generated garments can then be easily animated in a simulation system based on finite elements, using a rediscretization of the generated mesh and a reconstructed metric of the cloth surface.

Garment creation continues to be the most tedious part of the virtual clothing process. In this paper, we present an easy to use sketch-based cloth modeling approach. Contours can be easily sketched on a mannequin to generate quad meshes to represent pieces of cloth already fitted and draped. Typically, the clothing process depends greatly on the meshing scheme that has to infer its geometry from the input boundary. Our quad meshing scheme is based on discrete Coons patches but with arbitrary boundary input. We also apply the permanence principle to our topological solution to allow more control over the influence of the input boundary polyline on the interior output polygonal mesh. This facilitates the creation of folds that are strongest in curvature at the boundary and which diminish towards the interior. The generated garments can then be easily animated in a simulation system based on finite elements, using a rediscretization of the generated mesh and a reconstructed metric of the cloth surface.

This interactive application will allow visitors to play with garments in three dimensions, transforming them into creative, customizable and experimental objects. Based on touch screen technology and through a simple and attractive interface, visitors will be able to dress and customize a 3 dimensional virtual fashion model. The model will pose for you to show of the physically simulated garments in real time.

Hip osteoarthritis (OA) is one of the most common forms of musculoskeletal disorders. Different studies have shown that hip OA is a multi-factor disease. Malnutrition, genetics, obesity and infections were identified as marginal factors and the abnormal hip morphology as the most common reasons. Nevertheless, hip OA is considered idiopathic and needs, hence, to be further investigated. The aim of the study is to investigate the link between extreme repetitive movements and the development of hip OA. A subject-specific and non-invasive approach, which jointly considers anatomy, kinematics and dynamics, is proposed to analyze the mechanical behavior of cartilage during movements. This combination offers new opportunity to individualize the diagnostic and to understand the pathology. This approach is used to assess the stress distribution of dancers’ hip joint during different movements. The correlation between the simulation results and a clinical analysis performed by medical experts, strongly suggests that extreme movement could lead to early hip OA.

This paper presents a new haptic-based virtual environment system for diagnosis and rehabilitation of Traumatic Brain Injury (TBI) patients.By using the latest technologies, including Virtual Reality (VR), haptic force feedback and telecommunications, the system can work as an alternative to traditional labor intensive and expensive diagnosis and rehabilitation procedures for TBI patients.This paper also introduces a general approach to the design and prototyping of a haptic-based VR system for motor skill assessment and rehabilitation.A numerical model is presented to describe and record the motor skill assessment results and parameterize the rehabilitation training process.The prototype system demonstrates the potential for using advanced information and haptic-based VR technologies to build more effective and intelligent tools for healthcare.The specific techniques developed in this research can be used for motor-skill evaluation in clinical practice.

Musculoskeletal disorders (MSDs) account for the largest fraction of temporary and permanent disabilities. Osteoarthritis (OA) is one of the most common MSDs which is characterized by a degeneration of articular cartilages. Understanding and preventing OA are of paramount importance in our aging yet very active society, and in this context, computer-assisted models of articulations are highly demanded by biomechanical and medical communities. To investigate the causes of some idiopathic OA, we have devised a unique comprehensive methodology to simulate musculoskeletal models of human articulations. Built from a rich variety of acquisition modalities (MRI, Motion capture, Body scanning, etc.) and innovative research, these models are fully subject-specific and account for anatomy, motion and biomechanical behavior of the articulations. This paper presents a complete overview of the methodology with medical validation and clinical case studies.

Overload on the hip joint is considered by medical experts as principal cause of hip joint osteoarthritis (OA) which is characterized by the degeneration of the articular cartilages. The aim of this study is to investigate the correlation between extreme movements and the development of early OA. Thus, the mechanical behavior of dancer’s hip joint under movements characterized by large anatomical angles of the leg is analyzed. Dynamics simulation based on patientspecific model is used to assess the stress during these postures. The simulation results show a correlation between movements and stress depending on the applied load.

This paper describes a methodology for the simulation of musculoskeletal disorders. Our clinical study is related to osteoarthritis (OA) of the hip, a pathogenesis possibly due to impingements. These bone collisions lead to abnormal joint mechanics which is characterized by contact pressure and stress distribution upon the joint cartilages. The proposed methodology combines different approaches from modeling to simulation. The simulation is based on patient‐specific anatomical models, where acquisition modalities are noninvasive and flexible. Based on static magnetic resonance imaging (MRI) data, a discrete deformable models method is used for modeling the organs of the musculoskeletal system. Femoroacetabular movements are estimated using an optical motion capture system and are validated by a dynamic MRI analysis. To achieve accurate deformations, techniques to generate volumetric meshes are developed based on the medial axis (MA) information. Finally, a computationally efficient fast functional joint model is used to simulate the mechanical behavior of the soft tissues. The goal of such a simulation is to allow the investigation of the relevant contact and cartilages deformation under movement, which can be useful for diagnosis, pre‐ or post‐operative planning and training. This will benefit further developments in surgical techniques and minimally invasive procedures. Copyright © 2008 John Wiley & Sons, Ltd.

Recent mechanical models for cloth simulation have evolved toward accurate representation of elastic stiffness based on continuum mechanics, converging to formulations that are largely analogous to fast finite element methods. In the context of tensile deformations, these formulations usually involve the linearization of tensors, so as to express linear elasticity in a simple way. However, this approach needs significant adaptations and approximations for dealing with the nonlinearities resulting from large cloth deformations. Toward our objective of accurately simulating the nonlinear properties of cloth, we show that this linearization can indeed be avoided and replaced by adapted strain-stress laws that precisely describe the nonlinear behavior of the material. This leads to highly streamlined computations that are particularly efficient for simulating the nonlinear anisotropic tensile elasticity of highly deformable surfaces. We demonstrate the efficiency of this method with examples related to accurate garment simulation from experimental tensile curves measured on actual materials.

As computers become computationally more powerful, the gap between virtual and physical reality is continuously diminishing. Striving for increased accuracy, computer simulations are becoming more and more specialized by the day - but are less capable of generalization. There is currently no comprehensive physically-based simulation approach for real-time animation of deformable objects within one unique framework. The first step required to tackle this challenge is to investigate invariant aspects in the correlation between dynamic behavior and physical properties of objects with different shape and consistency. In this paper we discuss the mechanical behavior of deformable one-dimensional rods and two-dimensional surfaces: hair and clothes.

Many causes can be at the origin of hip osteoarthritis (e.g., cam/pincer impingements), but the exact pathogenesis for idiopathic osteoarthritis has not yet been clearly delineated. The aim of the present work is to analyze the consequences of repetitive extreme hip motion on the labrum cartilage. Our hypothesis is that extreme movements can induce excessive labral deformations and lead to early arthritis. To verify this hypothesis, an optical motion capture system is used to estimate the kinematics of patient-specific hip joint, while soft tissue artifacts are reduced with an effective correction method. Subsequently, a physical simulation system is used during motion to compute accurate labral deformations and to assess the global pressure of the labrum, as well as any local pressure excess that may be physiologically damageable. Results show that peak contact pressures occur at extreme hip flexion/abduction and that the pressure distribution corresponds with radiologically observed damage zones in the labrum.

This work describes a methodology for the simulation of the mechanical behavior of the dancers hip. Patient-specific anatomical and kinematical models are used as input to simulate the hip cartilages deformations during motion. Based on computer graphic techniques, this methodology allows a 3D visualization and assessment of pressure distribution, offering orthopedists a complementary tool for diagnosis.

Virtual Try On (VTO) applications are still under development even if a few simplified applications start to be available. A true VTO should let the user specify its measurements, so that a realistic avatar can be generated. Also, the avatar should be animatable so that the worn cloth can be seen in motion. This later statement requires two technologies: motion adaptation and real-time cloth simulation. Both have been extensively studied during the past decade, and state of the art techniques may now enable the creation of a high quality VTO, allowing a user to virtually try on garments while shopping online. This paper reviews the pieces that should be put together to build such an application.

For more than two decades, cloth simulation has been an active research area in computer graphics. In order to create efficient high-quality animations, techniques from many researchfields have to be thoroughly combined. The ongoing interest in thisfield is also due to the multidisciplinary nature of cloth simulation which spurs development and progress in collision detection, numerical time integration, constrained dynamics, or motion control, to name just a few areas. Beyond the very basic approaches, the complexity of the material can be daunting if no guidance is given. It is therefore the goal of this tutorial to provide the reader with an introduction and a guideline to the relevant matter. In order to provide a concise review, we will focus on advanced topics in cloth simulation, shedding light on both theoretical and practical aspects. This will pave the ground for those willing to implement a contemporaneous cloth simulation system as well as researchers who consider to start working in this area.

—While the animation and rendering techniques used in the domain of textile simulation have dramatically evolved during the last two decades, the ability to manipulate and modify virtual textiles intuitively using dedicated ergonomic devices has been definitely neglected. The project HAPTEX combines research in the field of textile simulation and haptic interfaces. HAPTEX aims to provide a virtual reality system allowing for multipoint haptic interaction with a piece of virtual fabric simulated in real-time. The fundamental research undertaken by the project ranges from the physics-based simulation of textiles to the design and development of novel tactile and force-feedback rendering strategies and interfaces.

Cloth simulation and fabric measurement are tightly linked areas of research. In order to obtain high quality animations of dressed models, the properties of the simulated garment must first be evaluated in an accurate and adapted way. As cloth is a very complex, isotropic material, the evaluation of its properties is difficult to achieve, and various approaches exist. Depending on the design of the simulation engine, the measurements will be done differently, so that the outputted parameters match the inputs required by the simulator. Various issues must be considered, and depending on the complexity of the simulated garments, tradeoffs must be made in order to reconcile the real features of the cloth (stitches, layers...) and the computational capacities of the simulator (numerical integration, collision detection...)