CN103559349A - Method for generating fabric simulation model on basis of geometrical measurement - Google Patents

Abstract

The invention discloses a method for generating a fabric simulation model on the basis of geometrical measurement, which comprises the following steps of: selecting a common garment fabric sample; carrying out material measurement of geometric attributes on the basis a fabric; carrying out geometric constraint deformation simulation on the basis of the fabric; carrying out geometric simulation verification on the basis of the fabric. The embodiment of the invention is implemented; the method obtains corresponding characteristic parameters which express the overhang characteristic of the fabric by directly measuring the real fabric sample, is directly applied to geometric simulation of the fabric and overcomes the defects of complex system and high cost on the basis of the physical KES-FB (Kawabata Evaluation System Fabric) and the like.

Description

A kind of method that cloth modeling based on dimensional measurement generates

Technical field

The present invention relates to Technique of Fabric Simulation field, be specifically related to a kind of method that cloth modeling based on dimensional measurement generates.

Background technology

At present, some physical test methods have been proposed to measure the flexible parameter of textile simulating.Textile Engineering researchers are directly by expensive testing apparatus, such as KES-FB system (Kawabata Evaluation System), FAST system (Fabric Assurance by Simple Testing), FAMOUS[3] (Fabric automatic measurement and optimization universal system) and ITT(Instron Tensile Tester) etc. determine and describe fabric physical parameter, too pay close attention to the self character of fabric, emphasize the impact on textile simulating of fabric construction and material property.

Textile flexibility parameter measurement equipment based on physics is expensive, and the physical parameter of test applies to the textile simulating modeling based on physics, cannot directly apply to the geometric simulative modeling of fabric.And the physical parameter of these measurements is applied in the textile simulating analogy method based on physics, need to solve more implicit expression kinetic equation at each time step, counting yield is lower.

Summary of the invention

The object of the invention is to relate to a kind of mode based on DATA REASONING and the theory of 3D grid surface deformation (how much), propose cloth modeling, realize the sense of reality effect of fabric and clothes fold.

A kind of method that the embodiment of the present invention provides cloth modeling based on dimensional measurement to generate, comprising:

Choose the conventional fabric sample of taking;

The material of the geometric attribute based on fabric is measured;

Geometrical constraint deformation emulating based on fabric;

Geometric simulation checking based on fabric.

The described conventional fabric sample of taking comprises: silk, denim, cotton, flax, nylon, dacron, wool; Or the fabric being formed by these materials.

The material measurement of the described geometric attribute based on fabric comprises:

Restorative measurement;

Stretchability is measured;

Flexibility is measured.

The material of the described geometric attribute based on fabric is measured and is also comprised:

The parameter estimation that material is measured, and to parameter fitting optimization.

The present invention has following beneficial effect, has overcome the textile simulating calculation of complex based on physics, the shortcoming that efficiency is lower.And the method, by directly measuring real fabric sample, obtains the characteristic parameter of corresponding performance fabric overhanging feature, directly applies to the geometric simulation of fabric, has overcome the system complex such as KES-FB based on physics, the shortcoming of cost costliness.

Accompanying drawing explanation

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, to the accompanying drawing of required use in embodiment or description of the Prior Art be briefly described below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skills, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.

Fig. 1 is the dimensional measurement system and device structural representation in the embodiment of the present invention;

Fig. 2 is the method schematic diagram of the restorative measurement in the embodiment of the present invention;

Fig. 3 is the method schematic diagram that the stretchability in the embodiment of the present invention is measured;

Fig. 4 is the method schematic diagram that the bendability in the embodiment of the present invention is measured;

Fig. 5 is the method flow diagram that the cloth modeling based on dimensional measurement in the embodiment of the present invention generates.

Embodiment

Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is only the present invention's part embodiment, rather than whole embodiment.Embodiment based in the present invention, those of ordinary skills, not making all other embodiment that obtain under creative work prerequisite, belong to the scope of protection of the invention.

The mode of this patent based on DATA REASONING and the theory of 3D grid surface deformation (how much), propose cloth modeling, realizes the sense of reality effect of fabric and clothes fold.Overcome the textile simulating calculation of complex based on physics, the shortcoming that efficiency is lower.And the method, by directly measuring real fabric sample, obtains the characteristic parameter of corresponding performance fabric overhanging feature, directly applies to the geometric simulation of fabric, has overcome the system complex such as KES-FB based on physics, the shortcoming of cost costliness.

This patent proposed a kind of for textile simulating the material measuring method based on how much.The method is by the real fabric sample of direct measurement, obtains the characteristic parameter of corresponding performance fabric overhanging feature.Form on this basis the description indexes system of a set of, science objective, reasonable to fabric Drape.By experiment, we have measured affects most important three how much variablees to fabric Drape, and by the building and quantitative analysis to measurement data of measurement environment, we can obtain reflecting the optimization characteristic parameter of unlike material fabric sample.

Material properties: when people puts on clothes and does different postures, because most of clothes cloth is not resilient material, the shape of fabric own is not stretched or compressed, but because its crooked character having, and there are Tuo La, collision etc. and make fabric face part produce different fold details.Therefore, the result of cloth simulation is wanted the really deformational behavior of emulating fabric, just need to consider the impact of different fabrics on its form, because our vision is very sensitive to the form of fabric, to a certain extent, we can identify the simple shape of fabric and variation.Different fabric attributes, makes it when dangling and play fold, present different effects.

All fabric samples, it has all shown non-linear and anisotropic fabric behavior separately.In textile simulating modeling, due to different fabric texture attributes, under the effect that is subject to different power, take fabric tensile deformation can occur, Bending Deformation and shearing deformation etc., these deformational behaviors are by definite relevant overhanging feature, fold characteristic and flexural property etc. of clothes wearing appearance.These characteristic relations are to the embodiment of clothing function and clothes fashion, and last dressing effect.The Computer Simulation effect of fabric is relevant with the specific category of fabric, and different classes of fabric has different wearability.For example, although it is soft for red silk, be not easy to occur tensile deformation.Therefore, the method for geometry of a kind of innovation of use that we propose is set up real experimental provision, is used for measuring three main key factors that can reflect fabric attribute, respectively: restorative, stretching and bendability.

Restorative measurement: for better, must obtain restorative after deformation of fabric, i.e. the draping property of fabric, we have designed the projected area ratio that a series of experiment carrys out test fabric sample.Fabric is launched entirely to put on the table, record its initial area.Then, after fabric sample is rolled into a mass by kneading, be put into fixing putting position, repeated test more than 10 times, is recorded its area change.First the number of black pixel point in statistical picture, total number of number/image slices vegetarian refreshments of area=image actual imaging size * black pixel point of black region.Whole survey instrument has been used Canon EOS550D(Japan and has been produced) one of slr camera (3.7fps and a DIGIC4processor), camera is 71.5cm from the focal distance of measuring fabric sample.See Fig. 2.

Stretchability is measured: in our method of testing, and other three summits on fixed fabric diagonal line, remaining that summit that stretches, stretches 10 times, all uses each time a tautness meter to stretch, and the scope of pulling force is at (400g, 900g), and direction of pull is 0 degree.Then the cornerwise length being stretched with ruler measurement.Record numerical value, and take the photo of each piece fabric sample under different stretch number of times simultaneously, see Fig. 3.

Flexibility is measured: we are by measuring the angle of elevation of the angle of bend of fabric crease and fold.Intuitively and directly obtain the geometric data about fabric flexibility performance.See Fig. 4.

Parameter estimation: in order to conclude the statistical probability distribution of unified samples, we are by normalization, maximal value and minimum value that the minimum value of the measurement data in every kind of fabric sample and maximal value are respectively to training sample.Normalization is between 0-1.By normalized result, can obtain three parameter θ of material properties _r, θ _s, θ _bbetween correlativity, and in projected area, the correlativity on the Geometrical change of length and height.

The fabric geometric simulation with material perception: the fabric texture attribute based on measuring, LiLiu[4] defined an optimizing process for corresponding overall nonlinear energy function with it, three energy terms that wherein comprise are respectively vertex position, the length of side and dihedral angle.In whole simulation process, we have used the method for material study, quantized data based on measuring and the weight of each energy term have been set up the mapping relations of material perception, above three energy terms are unified in to how much energy models that just obtained in a framework in final textile simulating.Whole deformation process is to work as E _p, E _l, E _pall reach minimum conditions.Therefore, textile simulating can be converted into the deformation process based on geometrical constraint.Our target will solve following nonlinear energy function minimization problem exactly:

$E\left(M^{\′}\right)=\underset{V}{\arg \min }(\mathrm{\α}{E}_p+\mathrm{\β}{E}_l+\mathrm{\γ}{E}_a)$

Three energy term weight α wherein, beta, gamma is three parameter θ of restorative, the stretchability of corresponding fabric and the relevant attribute of bendability respectively _r, θ _s, θ _b.

Concrete steps are as follows:

A: choose 10 kinds be of a size of 460 * 400mm2 conventional take fabric sample, 10 kinds of different material fabrics of this that choose in experiment have material constituent separately.May be summarized to be following more typical fabrics forms: silk, denim, cotton, flax, nylon, dacron, wool etc.

B: the material based on how much is measured

B1, restorative measurement: fabric is launched entirely to put on the table, record its initial area.After being rolled into a mass by kneading, fabric sample is put into fixing putting position, repeated test is more than 10 times, with Canon EOS550D(Japan, produce) one of slr camera (3.7fps and a DIGIC4processor), camera is 71.5cm photographic images from the focal distance of measuring fabric sample, records its area change.The number of black pixel point in statistical graph 2, total number of number/image slices vegetarian refreshments of area=image actual imaging size * black pixel point of black region.Measure data record after statistics.

B2, stretchability are measured: other three summits on fixed fabric diagonal line, and remaining that summit that stretches, stretches 10 times, all use each time a tautness meter to stretch, the scope of pulling force is at (400g, 900g), and direction of pull is cornerwise length that then 0 degree is stretched with ruler measurement.Record numerical value, and take the photo of each piece fabric sample under different stretch number of times simultaneously.The foundation of stretchability method of testing is as Fig. 3.

B3, flexibility are measured: fabric is launched entirely to put on the table.To fabric, apply external force, make it produce fold.Measure the high angle of the angle of bend of fabric crease and fold, and record, see Fig. 4.

The behaviors such as restorative, the stretchability of fabric sample and bendability can be described by following formula.

$\left\{\begin{array}{c}p\left(S_i\right)=\stackrel{\‾}{S_i^j}/S_i^{\mathrm{ini}},\\ p\left(L_i\right)=\stackrel{\‾}{L_i^j}/L_i^{\mathrm{ini}},\\ p\left(H_i\right)=\stackrel{\‾}{H_i^j}/H_i^{\max },\end{array}\right.$

the initial projected area of every kind of fabric sample,

it is averaging projection's area that the fabric sample after deformation occurs.

initial catercorner length,

it is the average catercorner length of all test sample books.In flexibility is measured,

represent the height of every kind of Sample Maximal fold,

the height mean value that correspondence measures.I and j represent respectively fabric sample number and measure number of times, and i ∈ [0,9], j ∈ [0,9].Amount to, every kind of fabric sample has been done respectively 10 restorative tests, 30 extension tests and 10 flexibility tests.Therefore for all samples, have 500 tests.

C: parameter estimation

C1, every kind of fabric sample have been done respectively 10 restorative tests, 30 extension tests and 10 flexibility tests.Therefore for all samples, have 500 tests.

C2, according to formula below, calculate restorative, stretchability and the bendability of fabric sample.

$\left\{\begin{array}{c}p\left(S_i\right)=\stackrel{\‾}{S_i^j}/S_i^{\mathrm{ini}},\\ p\left(L_i\right)=\stackrel{\‾}{L_i^j}/L_i^{\mathrm{ini}},\\ p\left(H_i\right)=\stackrel{\‾}{H_i^j}/H_i^{\max },\end{array}\right.$

C3, by normalization, maximal value and minimum value that the minimum value of the measurement data in every kind of fabric sample and maximal value are respectively to training sample.Normalization is between 0-1.As follows for every kind of normalized result of the restorative measurement data of fabric texture:

$\mathrm{\λ}\left(S_i\right)=\frac{p\left(S_i\right)-\min p\left(S_i\right)}{\max p\left(S_i\right)-\min p\left(S_i\right)}$

In like manner, can obtain every kind of fabric texture stretchability λ (L _i) and bendability λ (H _i) the normalized result of measurement data.

C4, parameter optimization, calculate three parameter θ of material properties according to following formula _r, θ _s, θ _bbetween correlativity, and in projected area, the correlativity on the Geometrical change of length and height.

$\left\{\begin{array}{c}{\∂}_R=\mathrm{\λ}\left(S_i\right)/\mathrm{\λ}\left(S_i\right)+\mathrm{\λ}\left(L_i\right)+\mathrm{\λ}\left(H_i\right),\\ {\∂}_S=\mathrm{\λ}\left(L_i\right)/\mathrm{\λ}\left(S_i\right)+\mathrm{\λ}\left(L_i\right)+\mathrm{\λ}\left(H_i\right),\\ {\∂}_B=\mathrm{\λ}\left(H_i\right)/\mathrm{\λ}\left(S_i\right)+\mathrm{\λ}\left(L_i\right)+\mathrm{\λ}\left(H_i\right).\end{array}\right.$

Finally, we have obtained the recovery attribute λ (S of fabric _i), stretching attribute λ (L _i), and crooked attribute λ (H _i) three parameters and between correlativity θ _r, θ _s, θ _b.

D. fabric geometric simulation checking

In order further to verify the validity of our method, we have provided a series of subjective evaluating mechanisms based on vision, have designed user investigation.Use the weight parameter that these study obtain and control constraint etc., can emulation to 100 kinds of last form effects of different fabric samples.We have chosen the 10 kind shape table effects the most similar to real pictures, the validity of coming as a comparison parameter of measurement to arrange.We have invited 100 users to participate in survey that (wherein man accounts for 50%, women accounts for 50%, the range of age is between 18 years old to 78 years old), please they evaluate 10 deformation effects that every kind of fabric sample elects and compare with the photo that true fabric sample takes, and provide similarity scoring.The statistics of result by inquiry, the similarity that we can obtain using these parameters that the effect that emulation obtains is set has reached more than 89%.Fig. 5 shows the method that the cloth modeling based on dimensional measurement in the embodiment of the present invention generates, and includes:

1, fabric geometric attribute is measured

For true fabric, carry out restorative test, stretchability test, bendability test;

Restorative parameter estimation, stretchability parameter estimation, bendability parameter estimation;

Parameter fitting is optimized.

2, geometrical constraint deformation emulating

Initial mesh, vertex position, the length of side, dihedral angle;

Geometric deformation energy.

3, the several simulating, verifyings of fabric

Fabric grid after emulation;

Realistic Texture mapping;

The real pictures contrast that simulation result and camera are clapped.

The present invention has following beneficial effect, and the cloth modeling generation method based on dimensional measurement can be measured the fabric attribute of fabric, and the textile simulating method with material perception can be simulated fabric behavior and the sense of reality effect of unlike material.In a plurality of fields such as design, animation, game, bringing into play extremely important effect.

One of ordinary skill in the art will appreciate that all or part of step in the whole bag of tricks of above-described embodiment is to come the hardware that instruction is relevant to complete by program, this program can be stored in a computer-readable recording medium, storage medium can comprise: ROM (read-only memory) (ROM, Read Only Memory), random access memory (RAM, Random Access Memory), disk or CD etc.

The method that the cloth modeling based on the dimensional measurement above embodiment of the present invention being provided generates is described in detail, applied specific case herein principle of the present invention and embodiment are set forth, the explanation of above embodiment is just for helping to understand method of the present invention and core concept thereof; , for one of ordinary skill in the art, according to thought of the present invention, all will change in specific embodiments and applications, in sum, this description should not be construed as limitation of the present invention meanwhile.

Claims (4)

1. the method that the cloth modeling based on dimensional measurement generates, is characterized in that, comprising:

Choose the conventional fabric sample of taking;

The material of the geometric attribute based on fabric is measured;

Geometrical constraint deformation emulating based on fabric;

Geometric simulation checking based on fabric.

2. the method that the cloth modeling based on dimensional measurement as claimed in claim 1 generates, is characterized in that, the described conventional fabric sample of taking comprises: silk, denim, cotton, flax, nylon, dacron, wool; Or the fabric being formed by these materials.

3. the method that the cloth modeling based on dimensional measurement as claimed in claim 1 generates, is characterized in that, the material measurement of the described geometric attribute based on fabric comprises:

Restorative measurement;

Stretchability is measured;

Flexibility is measured.

4. the method that the cloth modeling based on dimensional measurement as claimed in claim 3 generates, is characterized in that, the material of the described geometric attribute based on fabric is measured and also comprised:

The parameter estimation that material is measured, and to parameter fitting optimization.

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