Modeling dressed characters is known as a very tedious process. It u sually requires specifying 2D fabric patterns, positioning and assembling them in 3D, and then performing a physically-bas ed simulation. The latter accounts for gravity and collisions to compute the rest shape of the garment, with the ad equate folds and wrinkles. This paper presents a more intuitive way to design virtual clothing. We start w ith a 2D sketching system in which the user draws the contours and seam-lines of the garment directly on a v irtual mannequin. Our system then converts the sketch into an initial 3D surface using an existing method based on a p recomputed distance field around the mannequin. The system then splits the created surface into different pan els delimited by the seam-lines. The generated panels are typically not developable. However, the panels of a realistic garment must be developable, since each panel must unfold into a 2D sewing pattern. Therefore our sys tem automatically approximates each panel with a developable surface, while keeping them assembled along the s eams. This process allows us to output the corresponding sewing patterns. The last step of our method computes a natural rest shape for the 3D gar ment, including the folds due to the collisions with the body and gravity. The folds are generated using procedu ral modeling of the buckling phenomena observed in real fabric. The result of our algorithm consists of a realisticlooking 3D mannequin dressed in the designed garment and the 2D patterns which can be used for distortion free texture mapping. The patterns we create also allow us to sew real replicas of the virtual garments.

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Virtual Garments: A Fully Geometric Approach for Clothing Design

Experimental evaluation and constitutive modeling of non-proportional deformation for asymmetric steels

Formulas are derived for effective bending rigidity and bending length, based on the deformation of fabric strips in simple tests. The nine types of tests (including some new ones) involve a cantilever, heart loop, hanging pear loop, hanging ring, free fold, clamped fold, standing wrinkle (buckle), hanging wrinkle, and standing ring. No loads are applied and no special equipment is needed. Only the height of the deformed strip needs to be measured, along with the strip’s length, width, and weight. The results can be applied with different lengths of strips and different orientations (e.g., weft, warp, and bias directions). In the analysis, the fabric strip is modeled as an inextensible elastica. Polynomial approximations are developed that give the value of a nondimensional weight parameter (involving the weight, length, width, and bending rigidity) as a function of the height-to-length ratio. The bending rigidity and bending length can then be directly computed.

Formulas to determine fabric bending rigidity from simple tests

Published research works concerning fabric handle and its basic mechanical properties were surveyed in this review. Fabric handle and its mechanical properties have been studied continuously using KES system for various kinds of fabrics in the period between 1998 and 2005. Statistical investigation by neural network model has been very popular in these years and the accuracy of prediction is higher than that of conventional regression methods. Some novel works concerning fabric sound have also been reported. Quite a lot of works concerning drape behavior of fabrics, seam puckering, wrinkles and pillings have been carried out by using image processing system. In order to evaluate clothing comfort objectively, clothing pressure to human body is investigated precisely.

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Fabric Handle and Its Basic Mechanical Properties

Various types of special fibers are used for human body protection, mostly in the form of fiber-reinforced composites These composites are made of special fibers and matrix resin; however, they are often not comfortable for the wearer due to the lack of flexibility and air permeability This study focuses on an evaluation of human body protective performance against stabbing for various special fibers such as aramid, basalt, and steel fibers, being utilized in cotton hybrid forms These hybrid forms are designed to improve wearer comfort, while maintaining adequate anti-stab resistance Specimens prepared with various fabric densities are tested in terms of anti-stabbing performance, according to the NIJ standard In addition, we investigate the influence of factors such as fiber type, the number of fabric layers, fabric weight, and fabric density on anti-stabbing performance Results show that the penetration depth of the impactor, which punctures and protrudes through the specimens, decreases with the number of layers, the thickness, and the mass of the armor sample; however, these factors have different relationships according to the material type Consequently an objective evaluation of anti-stabbing performance is needed We suggest an anti-stabbing index that can be applied as a criterion to evaluate the antistabbing performance of various specimens woven with special fibers under different fabric conditions Using the new index, anti-stabbing performances of various specimens can be compared and raw material and fabric conditions that offer the most efficient anti-stabbing performance can be selected

Evaluation of anti-stabbing performance of fabric layers woven with various hybrid yarns under different fabric conditions

A fabric is a flexible material that it is highly affected by its own weight, which causes large deflections. The relationship between the bending moment and the curvature is nonlinear. This study presents a model for fabric buckling by considering the flexibility of the fabric as well as its nonlinearity in bending. The bending rigidity of the fabric is considered to be a function of its curvature to take into account the fabric's nonlinear bending properties. Based on Timoshenko's elastica theory and the Bernoulli-Euler theorem, geometric nonlinearity is also taken into account. Kawabata pure bending test results are applied to the governing equation. The values from the model. are compared with the experimental data. The results show a clear distinction from the linear model, where the nonlinear method coincides well with the experimental values. From data evaluated by the numerical analysis method, the critical buckling load is calculated.

Analyzing Fabric Buckling Based on Nonlinear Bending Properties

Impact analysis of 3D braided composites and laminated plane woven fabric composites was performed using the elasto-plastic constitutive law to describe the nonlinear, anisotropic and asymmetric properties of fiber-reinforced composites. As for the yield criterion, the modified Drucker-Prager yield criterion was utilized to represent the anisotropic and asymmetric properties, while the anisotropic hardening was described based on the kinematic hardening with the anisotropic evolution of the back-stress. Experiments to obtain the material parameters of the proposed constitutive law were also carried out based on uni-axial tension and compression tests for fiber-reinforced composites. Then, the proposed constitutive law was implemented into a finite element code and was verified by comparing the finite element simulation of the impact tests with experiments. In addition, impact performance of the braided composites and laminated composites was also compared with each other.

Impact Analysis of Fiber-reinforced Composites Based on Elasto-plastic Constitutive Law

The impact performance of laminated plain-woven fabric composites was analysed here using the elasto-plastic constitutive law, which can account for the anisotropic and asymmetric properties of fibre-reinforced plastics. The isotropic yield criterion was modified to account for the anisotropic and asymmetric initial yielding, while the kinematic hardening law with anisotropic evolution of back-stress was used for the anisotropic hardening behaviour. The impact tests were performed on laminated plain-woven composites. The simulation results for the impact tests compared well with experimental results.

Ki Ho Joo

Papers

Analyzing Fabric Buckling Based on Nonlinear Bending Properties

Impact Analysis of Fiber-reinforced Composites Based on Elasto-plastic Constitutive Law

Elasto-plastic analysis of the impact performance of woven fabric composites