Method for evaluating three-dimensional drape properties of a fabric

Abstract

The application discloses a kind of fabric three-dimensional draping performance evaluation methods, belong to fabric performance evaluation technical field, comprising: fabric three-dimensional draping form is scanned, constructs triangular mesh model, according to the three-dimensional coordinates of all vertexes in triangular mesh model, using triangulation algorithm will triangular mesh model be divided into several independent and disjoint triangles;According to the three-dimensional coordinates of the vertex of each triangle, the area of each triangle and the position data of the centroid of each triangle are calculated, the three-dimensional draping performance evaluation index of each triangle is calculated according to the position data of the centroid of each triangle, the three-dimensional draping performance evaluation index of fabric is calculated according to the three-dimensional draping performance evaluation index of each triangle and the area of each triangle, and the three-dimensional draping performance of fabric is evaluated through the three-dimensional draping performance evaluation index of fabric.The method can solve the problem that traditional two-dimensional projection method cannot capture wrinkle details and quantitative precision is insufficient, realize accurate quantification and stable evaluation of draping performance.

Description

TECHNICAL FIELD

[0001] The application relates to a fabric three-dimensional draping performance evaluation method and belongs to the technical field of fabric performance evaluation. BACKGROUND

[0002] The draping property of a fabric is a core index for measuring the appearance performance and practical value of the fabric and directly affects the modeling aesthetics of a garment, the draping effect of a decorative fabric and the shape stability of an industrial fabric. At present, the evaluation of the draping property of a fabric mainly adopts a standard test method (such as an umbrella projection method). Although the method is simple to operate, it has technical defects.

[0003] The essence of the umbrella projection method is a two-dimensional evaluation method, and its main defect is the lack of information dimension. The drape coefficient is calculated only by the projected area, the key shape characteristics in the three-dimensional space such as the wrinkle depth distribution and the curvature change of the curved surface are lost, and the shape evolution of the dynamic wrinkle formation path of the fabric from the flat laying to the stable state in the draping process cannot be recorded. Studies have shown that two fabrics with the same projected area may present completely different actual draping effects due to the difference in the wrinkle distribution, such as concentrated wrinkles and uniform wrinkles. In addition, the two-dimensional method is easily disturbed by environmental factors such as light and shooting angle, and the stability of the measured data is poor.

[0004] The draping test devices disclosed in Chinese patents with publication numbers CN209495975U, CN205826536U and CN2321002Y adopt different sensing or imaging technologies such as cameras and laser scanners, but their evaluation cores are still based on the static geometric parameters calculated by the two-dimensional projection or simplified models, such as the projected area, the contour radius and the drape coefficient. These methods cannot break through the framework of two-dimensional representation and cannot obtain and quantify the real three-dimensional geometric shape of the fabric. Therefore, they lack the deep description of the essence of the physical process of draping, especially the deformation energy.

[0005] The Chinese patents with publication numbers CN213517141U and CN209495975U try to optimize the test process, but their evaluation cores are still limited to the two-dimensional projection framework. Both of them improve the operation efficiency of the umbrella projection method by means of automation (single-chip time sequence control / mechanical position adjustment), but completely inherit the two-dimensional static evaluation paradigm, and finally output the drape coefficient derived from the projected area. The Chinese patent with the publication number CN209495975U only expands the position of the clamping point but does not go beyond the geometric calculation of the draping angle. This path dependence on the traditional methodology leads to the fact that it still belongs to the technical improvement within the two-dimensional evaluation system and cannot touch the core dimension transition of the three-dimensional displacement field analysis, and does not solve the problem of the lack of core dimension in dynamic evaluation of the draping performance. SUMMARY

[0006] The present application aims to provide a fabric three-dimensional draping performance evaluation method, which can solve the problem of the traditional two-dimensional projection method failing to capture the wrinkle details and the problem of insufficient quantitative accuracy, and realize accurate quantification and stable evaluation of the draping performance.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0008] In a first aspect, the present application provides a fabric three-dimensional draping performance evaluation method, comprising:

[0009] The fabric three-dimensional draping shape is scanned, a triangular mesh model is constructed, and according to the three-dimensional coordinates of all vertices in the triangular mesh model, the triangular mesh model is divided into a plurality of independent and non-intersecting triangles by using a triangulation algorithm;

[0010] The area of each triangle and the position data of the centroid of each triangle are calculated according to the three-dimensional coordinates of the vertices of each triangle, the three-dimensional draping performance evaluation index of each triangle is calculated according to the position data of the centroid of each triangle, the three-dimensional draping performance evaluation index of the fabric is calculated according to the three-dimensional draping performance evaluation index of each triangle and the area of each triangle, and the three-dimensional draping performance of the fabric is evaluated through the three-dimensional draping performance evaluation index of the fabric.

[0011] When the position data of the centroid is the lateral displacement and the longitudinal displacement of the centroid, the corresponding three-dimensional draping performance evaluation index is the draping displacement; when the position data of the centroid is the longitudinal displacement of the centroid, the corresponding three-dimensional draping performance evaluation index is the draping potential.

[0012] In combination with the first aspect, further, the scanning of the fabric three-dimensional draping shape and the construction of the triangular mesh model comprise:

[0013] A circular fabric sample without creases, damage and flat edges within a predetermined distance from the edge of the fabric is cut, a positioning hole is cut at the center of the fabric sample, and a plurality of reflective marker points are uniformly pasted on the surface of the fabric sample;

[0014] The center of the fabric sample is aligned with the center of the upper clamping disc and the center of the lower clamping disc of the draping tester, the positioning column of the lower clamping disc is sequentially inserted through the positioning hole of the fabric sample and the center hole of the upper clamping disc, and the fabric sample is clamped so that the fabric sample maintains natural three-dimensional draping without pulling;

[0015] The fabric sample is scanned at multiple angles to obtain complete three-dimensional data of the three-dimensional draping shape of the fabric sample;

[0016] An initial triangular mesh model is generated according to the complete three-dimensional data of the three-dimensional draping shape of the fabric sample;

[0017] The initial triangular mesh model is repaired for holes and cleaned for non-manifold edges to obtain the triangular mesh model.

[0018] In conjunction with the first aspect, further, the method for obtaining the three-dimensional coordinates of all vertices in the triangular mesh model includes: taking the lower surface of the upper clamping disk as the reference plane, the center of the circle on the lower surface of the upper clamping disk as the origin, and the direction perpendicular to the reference plane upwards as... In the positive direction of the axis, with the horizontal projection plane of the fabric sample as... shaft and Construct a three-dimensional coordinate system in the orthogonal plane of the axes to obtain the three-dimensional coordinates of all vertices in the triangular mesh model.

[0019] In conjunction with the first aspect, further, based on the three-dimensional coordinates of all vertices in the triangular mesh model, the triangulation algorithm is used to divide the triangular mesh model into several independent and non-intersecting triangles. This includes: importing the three-dimensional coordinates of all vertices in the triangular mesh model into the programming software in the format of an array file; calling the triangulation algorithm; using the imported array file of the three-dimensional coordinates of all vertices as input parameters; generating several independent and non-intersecting triangles; and simultaneously generating the position index of the vertices of each triangle in the three-dimensional coordinate array file.

[0020] In conjunction with the first aspect, the formula for calculating the area of ​​each triangle is as follows:

[0021] ;

[0022] in, Indicates the first The area of ​​each triangle, , , They represent the first The cross product of the vectors of the triangles is axis, axis, Components of the axis, , , They represent the first The three vertices of a triangle Axis coordinates , , They represent the first The three vertices of a triangle Axis coordinates , , They represent the first The three vertices of a triangle Axis coordinates.

[0023] In conjunction with the first aspect, the formula for calculating the lateral displacement of the centroid of each triangle is as follows:

[0024] ;

[0025] wherein, denotes the lateral displacement of the centroid of the th triangle, denotes the radius of the upper clamping disc, , denote the axis coordinate, axis coordinate of the centroid of the th triangle, respectively;

[0026] The calculation formula of the longitudinal displacement of the centroid of each triangle is:

[0027] ;

[0028] wherein, denotes the longitudinal displacement of the centroid of the th triangle, , , denote the axis coordinate of the three vertices of the th triangle, respectively.

[0029] In combination with the first aspect, further, the calculation formula of the overhang displacement of each triangle is:

[0030] ;

[0031] wherein, denotes the overhang displacement of the th triangle, , denote the lateral displacement and the longitudinal displacement of the centroid of the th triangle, respectively;

[0032] The calculation formula of the overhang displacement of the fabric is:

[0033] ;

[0034] wherein, denotes the overhang displacement of the fabric, denotes the area of the th triangle, denotes the total number of triangles.

[0035] In combination with the first aspect, further, the calculation formula of the overhang potential of each triangle is:

[0036] ;

[0037] wherein, denotes the overhang potential of the a longitudinal displacement of the centroid of the i-th triangle, a longitudinal displacement of the centroid of the i-th triangle, a longitudinal displacement of the centroid of the i-th triangle, a gravitational acceleration;

[0038] The formula for calculating the drape potential of the fabric is:

[0039]

[0040] wherein, a drape potential of the fabric, an area of the i-th triangle, an area of the i-th triangle, a total number of triangles.

[0041] In a second aspect, the present application provides a device for evaluating the three-dimensional drape performance of a fabric, comprising:

[0042] a model construction module, configured to scan the three-dimensional drape shape of the fabric, construct a triangular mesh model, and divide the triangular mesh model into a plurality of independent and non-intersecting triangles using a triangulation algorithm according to the three-dimensional coordinates of all vertices in the triangular mesh model;

[0043] a performance evaluation module, configured to calculate the area of each triangle and the position data of the centroid of each triangle according to the three-dimensional coordinates of the vertices of each triangle, calculate the three-dimensional drape performance evaluation index of each triangle according to the position data of the centroid of each triangle, calculate the three-dimensional drape performance evaluation index of the fabric according to the three-dimensional drape performance evaluation index of each triangle and the area of each triangle, and evaluate the three-dimensional drape performance of the fabric through the three-dimensional drape performance evaluation index of the fabric;

[0044] wherein, when the position data of the centroid is the lateral displacement and the longitudinal displacement of the centroid, the corresponding three-dimensional drape performance evaluation index is the drape displacement; and when the position data of the centroid is the longitudinal displacement of the centroid, the corresponding three-dimensional drape performance evaluation index is the drape potential.

[0045] In a third aspect, the present application provides a computer device, comprising:

[0046] a storage medium, configured to store a computer program;

[0047] a processor, configured to execute the computer program to implement the fabric three-dimensional drape performance evaluation method of the first aspect.

[0048] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program is executed by a processor to implement the fabric three-dimensional drape performance evaluation method of the first aspect.

[0049] ​In a fifth aspect, the present application provides a computer program product comprising a computer program which, when executed by a processor, implements the fabric three-dimensional drape performance evaluation method of the first aspect.

[0050] Compared with the prior art, the present application has the following advantages:

[0051] The fabric three-dimensional drape performance evaluation method provided by the present application constructs a triangular mesh model through three-dimensional scanning, divides the triangular mesh model into independent triangles using a triangulation technique, constructs a drape displacement calculation formula in combination with the lateral displacement and longitudinal displacement of the centroid of each triangle and the area of each triangle, or constructs a drape potential calculation formula in combination with the longitudinal displacement of the centroid of each triangle and the area of each triangle, realizes quantitative analysis of drape displacement distribution, solves the defect that the traditional two-dimensional projection method (such as the umbrella method) cannot capture local wrinkle details, and provides a more stable, comprehensive quantitative basis for drape performance evaluation of complex fabrics (such as blended fabrics). BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 is a flowchart of the fabric three-dimensional drape performance evaluation method provided by the embodiment of the present application;

[0053] Figure 2 is a schematic diagram of a triangular mesh model provided by the embodiment of the present application;

[0054] Figure 3 is a schematic diagram of part of the triangular mesh model after triangulation provided by the embodiment of the present application, wherein plane 1 represents a reference plane, h1 and h2 respectively represent the longitudinal displacement of two triangles in the fabric relative to the reference plane, DGP1 and DGP2 respectively represent the drape potential of the two triangles in the fabric, and g represents the acceleration of gravity. DETAILED DESCRIPTION

[0055] The technical solutions of the present application will be further described in detail below in combination with specific embodiments.

[0056] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application. The technical features in the embodiments of the present application and the embodiments can be combined with each other without conflict.

[0057] The embodiment of the present application provides a fabric three-dimensional drape performance evaluation method, comprising:

[0058] scan the three-dimensional draping form of the fabric, construct a triangular mesh model, and according to the three-dimensional coordinates of all vertices in the triangular mesh model, the triangular mesh model is divided into a plurality of independent and non-intersecting triangles by using a triangulation algorithm;

[0059] According to the three-dimensional coordinates of the vertices of each triangle, the area of each triangle and the position data of the centroid of each triangle are calculated, the three-dimensional draping performance evaluation index of each triangle is calculated according to the position data of the centroid of each triangle, the three-dimensional draping performance evaluation index of the fabric is calculated according to the three-dimensional draping performance evaluation index of each triangle and the area of each triangle, and the three-dimensional draping performance of the fabric is evaluated through the three-dimensional draping performance evaluation index of the fabric.

[0060] When the position data of the centroid is the lateral displacement and the longitudinal displacement of the centroid, the corresponding three-dimensional draping performance evaluation index is the draping displacement; when the position data of the centroid is the longitudinal displacement of the centroid, the corresponding three-dimensional draping performance evaluation index is the draping potential.

[0061] The fabric three-dimensional draping performance evaluation method provided by the embodiment of the application can accurately represent the three-dimensional form of the fabric, has clear physical meaning and high stability, is a key breakthrough to solve the inherent defects of the traditional two-dimensional method, such as dimension loss and weak physical correlation, is crucial for deepening the understanding of the fabric draping mechanism, and has important practical significance for the research and development of new textile materials, the fine optimization of garment process, and the performance prediction of industrial cloth.

[0062] Figure 1 The flowchart is a fabric three-dimensional draping performance evaluation method provided by the embodiment of the application, and only the logical order of the method is shown. Figure 1 The steps shown or described can be completed in an order different from that shown.

[0063] The fabric three-dimensional draping performance evaluation method provided by the embodiment of the application can be applied to a terminal and can be executed by a fabric three-dimensional draping performance evaluation device.

[0064] The embodiment of the application provides a fabric three-dimensional draping performance evaluation method, which comprises the following steps:

[0065] scan the three-dimensional draping form of the fabric, construct a triangular mesh model, and according to the three-dimensional coordinates of all vertices in the triangular mesh model, the triangular mesh model is divided into a plurality of independent and non-intersecting triangles by using a triangulation algorithm;

[0066] The area of each triangle and the lateral displacement and longitudinal displacement of the centroid of each triangle are calculated according to the three-dimensional coordinates of the vertices of each triangle, the overhang displacement of each triangle is calculated according to the lateral displacement and longitudinal displacement of the centroid of each triangle, the overhang displacement of the fabric is calculated according to the overhang displacement of each triangle and the area of each triangle, and the three-dimensional overhang performance of the fabric is evaluated through the overhang displacement of the fabric.

[0067] In the embodiment, the scanning of the three-dimensional overhang shape of the fabric and the construction of the triangular mesh model specifically include the following steps.

[0068] Step 1: A circular fabric sample without creases, damage and flat edges within a predetermined distance from the edge of the fabric is cut, a positioning hole is cut at the center of the fabric sample, and a plurality of reflective marker points are uniformly pasted on the surface of the fabric sample.

[0069] Specifically, a circular fabric sample with a diameter of 240 mm, without creases, damage and flat edges within 100 mm from the edge of the fabric is cut, a positioning hole with a diameter of 1 mm is cut at the center of the fabric sample, 15 to 30 reflective marker points are uniformly pasted on the surface of the fabric sample, the distance between adjacent marker points is set to 30 to 50 mm, and the fabric sample is balanced for moisture adjustment in a standard atmospheric environment (temperature of 18 to 22°C, relative humidity of 61 to 69%).

[0070] Step 2: The center of the fabric sample is aligned with the center of the upper clamping disc and the center of the lower clamping disc of the overhang tester, the positioning column of the lower clamping disc is sequentially inserted through the positioning hole of the fabric sample and the center hole of the upper clamping disc, and the fabric sample is clamped so that the fabric sample maintains natural three-dimensional overhang without pulling.

[0071] Step 3: The fabric sample is scanned at multiple angles to obtain complete three-dimensional data of the three-dimensional overhang shape of the fabric sample.

[0072] Specifically, the fabric sample is scanned at multiple angles by using a handheld three-dimensional scanner to obtain complete three-dimensional data of the three-dimensional overhang shape of the fabric sample.

[0073] Step 4: An initial triangular mesh model is generated according to the complete three-dimensional data of the three-dimensional overhang shape of the fabric sample.

[0074] Specifically, the initial triangular mesh model in STL format of the scanning result is exported by using a three-dimensional scanning data processing software.

[0075] Step 5: The initial triangular mesh model is repaired for holes and cleaned for non-manifold edges to obtain a triangular mesh model.

[0076] Specifically, the initial triangular mesh model is imported into a reverse engineering software for hole repair and non-manifold edge cleaning to obtain a triangular mesh model as shown in Figure 2The closed manifold triangular mesh model shown.

[0077] In this embodiment, the method for obtaining the three-dimensional coordinates of all vertices in the triangular mesh model specifically comprises: taking the lower surface of the clamping disc as a reference plane, taking the center of the lower surface of the clamping disc as an origin, taking the direction perpendicular to the reference plane upward as the positive direction of the Z-axis, taking the horizontal projection plane of the fabric sample as the orthogonal plane of the X-axis and the Y-axis, and constructing a three-dimensional coordinate system to obtain the three-dimensional coordinates of all vertices in the triangular mesh model.

[0078] Specifically, the three-dimensional coordinate system is constructed by using reverse engineering software, and the three-dimensional coordinates of all vertices in the triangular mesh model are exported.

[0079] In this embodiment, according to the three-dimensional coordinates of all vertices in the triangular mesh model, the triangular mesh model is divided into a plurality of independent and non-intersecting triangles by using a triangulation algorithm, which specifically comprises: importing the three-dimensional coordinates of all vertices in the triangular mesh model in the form of an array file into a programming software, calling a triangulation algorithm, taking the three-dimensional coordinate array file of all vertices as an input parameter, generating a plurality of independent and non-intersecting triangles, and simultaneously generating the position index of the vertices of each triangle in the three-dimensional coordinate array file.

[0080] Specifically, the three-dimensional coordinates of all vertices in the triangular mesh model are imported into MATLAB software in the form of an array file, a triangulation algorithm is called, and in MATLAB software, a built-in delaunay Triangulation function is called to take the imported three-dimensional coordinate data file as an input parameter, or in a Python programming environment, a Delaunay function is called through a scipy.spatial library to generate a triangle set, and through the operation of the function, a plurality of independent and non-intersecting triangles are generated, and the position index of the vertices of each triangle in the three-dimensional coordinate array file is output, that is, the position index of the three vertices corresponding to each triangle in the three-dimensional coordinate array file. The total number of triangles is controlled to be in the range of 80000 to 100000.

[0081] In this embodiment, the coordinates of the three vertices of the first triangle are defined as , , , , , , , , , , ​​​​, , .

[0082] The formula for calculating the area of ​​each triangle is:

[0083] ;

[0084] in, Indicates the first The area of ​​each triangle, in mm² 2 , , , They represent the first The cross product of the vectors of the triangles is axis, axis, Components of the axis, , , They represent the first The three vertices of a triangle Axis coordinates , , They represent the first The three vertices of a triangle Axis coordinates , , They represent the first The three vertices of a triangle Axis coordinates.

[0085] Specifically, the first The side vectors of the triangles are:

[0086] ;

[0087] No. The cross product of the vectors of the triangle is:

[0088] .

[0089] The formulas for calculating the lateral and longitudinal displacements of the centroids of each triangle are as follows:

[0090] ;

[0091] in, , They represent the first The lateral and longitudinal displacements of the centroid of the triangle, both in mm. This indicates the radius of the upper clamping plate, in mm. , respectively represent the axis coordinates of the centroid of the first axis coordinates of the centroid of the first axis coordinates of the centroid of the first axis coordinates of the centroid of the first

[0092] Specifically, the radius of the upper clamping disc is 60 mm.

[0093] The calculation formula of the sag displacement of each triangle is:

[0094] ;

[0095] wherein, represents the sag displacement of the first triangle, in mm.

[0096] The calculation formula of the sag displacement of the fabric is:

[0097] ;

[0098] wherein, represents the sag displacement of the fabric, in mm, represents the total number of triangles.

[0099] The sag displacement method provided by the embodiment of the present application is used to evaluate the sag performance of two fabrics with different materials, which specifically includes the following steps:

[0100] Step 1: Experimental material and sample preparation;

[0101] In this embodiment, two typical fabrics are selected as test objects:

[0102] Fabric 1: bamboo fiber fabric (100% bamboo fiber), with a grammage of 147 g / m², representing a traditional natural fiber fabric;

[0103] Fabric 2: blended fabric (20% polyester, 69% cotton, 11% nylon), with a grammage of 136 g / m², representing a common functional composite fabric.

[0104] Ten independent samples (uniform size of 36 cm in diameter) are taken from each fabric to ensure that the samples are not damaged or wrinkled, and are placed in a standard atmospheric environment for 24 h before testing.

[0105] Step 2: Multi-method synchronous testing;

[0106] In this embodiment, two methods are used to test the sag performance of each sample:

[0107] The first method is the standard sag coefficient method, which uses a fabric sag tester to fix the fabric and measure the sag shape;

[0108] The second kind of overhang displacement method provided in the embodiment, the calculation formula of the overhang displacement of the fabric is:

[0109] .

[0110] Each method is repeated 10 times for the same sample, and the dispersion data of the test results is recorded.

[0111] Step three: comparative analysis of test result stability;

[0112] In the embodiment, the test stability is quantified by calculating the coefficient of variation (CV = standard deviation / average value x 100%) of the 10 test results of the two methods, and the results are shown in Tables 1 and 2.

[0113] Table 1: statistical comparison of different test methods for bamboo fiber fabric

[0114] .

[0115] Table 2: statistical comparison of different test methods for blended fabric

[0116] .

[0117] Step four: conclusion verification.

[0118] From the data in Tables 1 and 2 in the embodiment, it can be seen that:

[0119] (1) The test stability of the overhang displacement method provided in the embodiment on different fabrics is significantly better than that of the standard overhang coefficient method:

[0120] Bamboo fiber fabric: the coefficient of variation of the overhang displacement method (0.61%) is reduced by 91.5% compared with the standard overhang coefficient method (7.17%);

[0121] Blended fabric: the coefficient of variation of the overhang displacement method (0.71%) is reduced by 90.6% compared with the standard overhang coefficient method (7.56%);

[0122] (2) The overhang displacement method provided in the embodiment effectively reduces the influence of human operation error and environmental interference in the standard overhang coefficient method through fine modeling of three-dimensional point cloud and potential quantization, and provides a more stable and reliable quantitative basis for overhang performance evaluation.

[0123] The embodiment of the present application provides a fabric three-dimensional overhang performance evaluation method, comprising:

[0124] The fabric three-dimensional overhang shape is scanned, a triangular mesh model is constructed, and according to the three-dimensional coordinates of all vertices in the triangular mesh model, the triangular mesh model is divided into a plurality of independent and non-intersecting triangles by using a triangular division algorithm;

[0125] The area of each triangle and the longitudinal displacement of the centroid of each triangle are calculated according to the three-dimensional coordinates of the vertices of each triangle, the overhang potential of each triangle is calculated according to the longitudinal displacement of the centroid of each triangle, the overhang potential of the fabric is calculated according to the overhang potential of each triangle and the area of each triangle, and the three-dimensional overhang performance of the fabric is evaluated through the overhang potential of the fabric.

[0126] In this embodiment, the scanning of the three-dimensional overhang shape of the fabric and the construction of the triangular mesh model specifically include the following steps.

[0127] Step 1: A circular fabric sample without creases, damage and flat edges within a predetermined distance from the edge of the fabric is cut, a positioning hole is cut at the center of the fabric sample, and a plurality of reflective marker points are uniformly pasted on the surface of the fabric sample.

[0128] Specifically, a circular fabric sample with a diameter of 240 mm, without creases, damage and flat edges within 100 mm from the edge of the fabric is cut, a positioning hole with a diameter of 1 mm is cut at the center of the fabric sample, 15 to 30 reflective marker points are uniformly pasted on the surface of the fabric sample, the distance between adjacent marker points is set to 30 to 50 mm, and the fabric sample is balanced for moisture adjustment in a standard atmospheric environment (temperature of 18 to 22°C, relative humidity of 61% to 69%).

[0129] Step 2: Align the center of the fabric sample with the center of the upper clamping disc and the center of the lower clamping disc of the overhang tester, pass the positioning column of the lower clamping disc through the positioning hole of the fabric sample and the center hole of the upper clamping disc in turn, clamp the fabric sample, and make the fabric sample maintain natural three-dimensional overhang without pulling;

[0130] Step 3: Multi-angle scanning of the fabric sample is performed to obtain complete three-dimensional data of the three-dimensional overhang shape of the fabric sample.

[0131] Specifically, the fabric sample is multi-angle scanned by using a handheld three-dimensional scanner to obtain complete three-dimensional data of the three-dimensional overhang shape of the fabric sample.

[0132] Step 4: An initial triangular mesh model is generated according to the complete three-dimensional data of the three-dimensional overhang shape of the fabric sample.

[0133] Specifically, the initial triangular mesh model in STL format of the scanning result is exported by using a three-dimensional scanning data processing software.

[0134] Step 5: The initial triangular mesh model is subjected to hole repair and non-manifold edge cleaning to obtain a triangular mesh model.

[0135] Specifically, the initial triangular mesh model is imported into a reverse engineering software for hole repair and non-manifold edge cleaning to obtain a closed manifold triangular mesh model.

[0136] In this embodiment, obtaining the three-dimensional coordinates of all vertices in the triangular mesh model specifically includes: taking the lower surface of the clamping disc as the reference plane, taking the center of the lower surface of the clamping disc as the origin, taking the direction perpendicular to the reference plane upward as the positive direction of the Z-axis, taking the horizontal projection plane of the fabric sample as the X-Y plane, taking the positive direction of the X-axis and the positive direction of the Y-axis as the positive direction of the X-axis and the positive direction of the Y-axis, respectively, and taking the orthogonal plane of the X-axis and the Y-axis as the X-Y plane, constructing a three-dimensional coordinate system, and obtaining the three-dimensional coordinates of all vertices in the triangular mesh model.

[0137] Specifically, a three-dimensional coordinate system is constructed by using reverse engineering software, and the three-dimensional coordinates of all vertices in the triangular mesh model are exported.

[0138] In this embodiment, according to the three-dimensional coordinates of all vertices in the triangular mesh model, the triangular mesh model is divided into a plurality of independent and non-intersecting triangles by using a triangulation algorithm, specifically including: importing the three-dimensional coordinates of all vertices in the triangular mesh model in the form of an array file into a programming software, calling a triangulation algorithm, taking the three-dimensional coordinate array file of all vertices as an input parameter, generating a plurality of independent and non-intersecting triangles as shown in Figure 3 , and simultaneously generating the position index of the vertices of each triangle in the three-dimensional coordinate array file.

[0139] Figure 3 In the formula, plane 1 represents the reference plane, which is used to define the initial plane position of the fabric and define the spatial coordinate system of the gravity direction, h1 and h2 respectively represent the longitudinal displacement of two triangles in the fabric relative to the reference plane, DGP1 and DGP2 respectively represent the draping potential of two triangles in the fabric, and g represents the acceleration of gravity.

[0140] Specifically, the three-dimensional coordinates of all vertices in the triangular mesh model are imported into MATLAB software in the form of an array file, a triangulation algorithm is called, the built-in delaunay Triangulation function is called in MATLAB software, the imported three-dimensional coordinate data file is taken as an input parameter, or in a Python programming environment, the Delaunay function is called through the scipy.spatial library, a triangle set is generated, and independent and non-intersecting triangles are generated, and the position index of the vertices of each triangle in the three-dimensional coordinate array file is output, that is, the position index of the three vertices corresponding to each triangle in the three-dimensional coordinate array file. Among them, the total number of triangles is controlled to be in the range of 80000 to 100000.

[0141] In this embodiment, the three vertices of the first triangle are defined as , , , ​​​The coordinates are respectively , , , No. The centroid of the triangle The coordinates are ,in, , , .

[0142] The formula for calculating the area of ​​each triangle is:

[0143] ;

[0144] in, Indicates the first The area of ​​each triangle, in mm² 2 , , , They represent the first The cross product of the vectors of the triangles is axis, axis, Components of the axis, , , They represent the first The three vertices of a triangle Axis coordinates , , They represent the first The three vertices of a triangle Axis coordinates , , They represent the first The three vertices of a triangle Axis coordinates.

[0145] Specifically, the first The side vectors of the triangles are:

[0146] ;

[0147] No. The cross product of the vectors of the triangle is:

[0148] .

[0149] The formula for calculating the longitudinal displacement of the centroid of each triangle is as follows:

[0150] ;

[0151] in, Indicates the first the longitudinal displacement of the centroid of the triangle, in mm.

[0152] The formula for calculating the sag potential of each triangle is:

[0153]

[0154] wherein, represents the sag potential of the i-th triangle, in J / kg, represents the gravitational acceleration (9.8 m / s 2 ).

[0155] The formula for calculating the sag potential of the fabric is:

[0156]

[0157] wherein, represents the sag potential of the fabric, in J / kg, represents the total number of triangles.

[0158] In this embodiment, the formula derivation is based on the mass-area equivalence principle, specifically including:

[0159] The expression of the gravitational potential energy of the fabric is wherein, is the mass of the fabric, in kg, is the gravitational acceleration (9.8 m / s 2 ), is the centroid height, i.e., the longitudinal displacement of the centroid, in m;

[0160] The gravitational potential energy is converted to (wherein, is the area of the fabric, in mm 2 , is the grammage of the fabric, in kg / m 2 ) by ;

[0161] The sag potential per unit mass is defined as ;

[0162] The formula for calculating the sag potential of the fabric is obtained by integration and normalization of the area wherein, the unit of is J / kg.

[0163] The sag potential method provided by the embodiment of the present application is used to evaluate the sag performance of two fabrics with different materials, specifically including the following steps:

[0164] ​​​Step 1: Experimental materials and sample preparation

[0165] Two typical fabrics were selected as test objects in this example:

[0166] Fabric 1: Pure cotton fabric, with a weight of 240 g / m², commonly used cotton fabric, representing traditional natural fiber fabric;

[0167] Fabric 2: Blended fabric (54% viscose, 36.3% nylon, 9.7% spandex), with a weight of 235 g / m², representing a common functional composite fabric.

[0168] For each fabric, 7 independent samples (uniform size of 24 cm in diameter) were taken, ensuring that the samples were free of damage and wrinkles, and were placed in a standard atmospheric environment for 24 hours before testing.

[0169] Step 2: Multi-method synchronous testing

[0170] In this example, each sample was tested for drape performance using two methods:

[0171] The first method was the standard drape coefficient method, which measured the drape shape by fixing the fabric on a fabric drape tester support;

[0172] The second method was the drape potential method provided in this example, and the calculation formula for the drape potential of the fabric was:

[0173] .

[0174] Each method was repeated 7 times for the same sample, and the dispersion data of the test results was recorded.

[0175] Step 3: Comparative analysis of test result stability

[0176] In this example, the coefficient of variation (CV = standard deviation / average value x 100%) of the 7 test results of the two methods was calculated to quantify the test stability, and the results are shown in Tables 3 and 4.

[0177] Table 3: Statistical comparison of different test methods for pure cotton fabric

[0178] .

[0179] Table 4: Statistical comparison of different test methods for blended fabric

[0180] .

[0181] Step 4: Conclusion verification

[0182] From the data in Tables 3 and 4 in this example, we can see that:

[0183] (1) The test stability of the overhang potential method provided in this embodiment on different fabrics is significantly better than that of the standard overhang coefficient method:

[0184] Pure cotton fabric: the variation coefficient (0.42%) of the overhang potential method is reduced by 86.7% compared with the standard overhang coefficient method (3.16%);

[0185] Blended fabric: the variation coefficient (2.62%) of the overhang potential method is reduced by 73.3% compared with the standard overhang coefficient method (9.83%);

[0186] (2) The overhang potential method provided in this embodiment effectively reduces the influence of human operation errors and environmental interference in the standard overhang coefficient method through fine modeling and potential quantization of three-dimensional point clouds, and provides a more stable and reliable quantitative basis for overhang performance evaluation.

[0187] The embodiment of the present application provides a fabric three-dimensional overhang performance evaluation device, comprising:

[0188] A model construction module is configured to scan the three-dimensional overhang shape of the fabric, construct a triangular mesh model, and divide the triangular mesh model into a plurality of independent and non-intersecting triangles by using a triangulation algorithm according to the three-dimensional coordinates of all vertices in the triangular mesh model.

[0189] A performance evaluation module is configured to calculate the area of each triangle and the position data of the centroid of each triangle according to the three-dimensional coordinates of the vertices of each triangle, calculate the three-dimensional overhang performance evaluation index of each triangle according to the position data of the centroid of each triangle, calculate the three-dimensional overhang performance evaluation index of the fabric according to the three-dimensional overhang performance evaluation index of each triangle and the area of each triangle, and evaluate the three-dimensional overhang performance of the fabric through the three-dimensional overhang performance evaluation index of the fabric.

[0190] When the position data of the centroid is the lateral displacement and the longitudinal displacement of the centroid, the corresponding three-dimensional overhang performance evaluation index is the overhang displacement; when the position data of the centroid is the longitudinal displacement of the centroid, the corresponding three-dimensional overhang performance evaluation index is the overhang potential.

[0191] The fabric three-dimensional overhang performance evaluation device provided in the embodiment of the present application can execute the fabric three-dimensional overhang performance evaluation method provided in the embodiment of the present application, and has the corresponding function modules and beneficial effects of the execution method.

[0192] The embodiment of the present application provides a computer device, comprising:

[0193] A storage medium is configured to store a computer program.

[0194] A processor is configured to execute the computer program to implement the fabric three-dimensional overhang performance evaluation method provided in the embodiment of the present application.

[0195] The embodiment of the present application provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to realize the fabric three-dimensional draping performance evaluation method provided by the embodiment of the present application.

[0196] The embodiment of the present application provides a computer program product, which comprises a computer program, and the computer program is executed by a processor to realize the fabric three-dimensional draping performance evaluation method provided by the embodiment of the present application.

[0197] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system or a computer program product. Therefore, the present application can adopt a completely hardware embodiment, a completely software embodiment or an embodiment combining software and hardware aspects. Moreover, the present application can adopt a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program codes.

[0198] The present application is described with reference to flowcharts and / or block diagrams of the method, device (system) and computer program product according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be realized by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, a special purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device that realizes the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks Figure 1 The functions specified in one or more flows and / or blocks

[0199] These computer program instructions can also be stored in a computer readable memory capable of guiding a computer or other programmable data processing device to work in a specific way, so that the instructions stored in the computer readable memory produce a product including instruction devices, which realize the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks Figure 1 The functions specified in one or more flows and / or blocks

[0200] These computer program instructions can also be loaded into a computer or other programmable data processing device, so that a series of operation steps are performed on the computer or other programmable device to produce a computer implemented process, so that the instructions executed on the computer or other programmable device provide a process for realizing the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks Figure 1 The functions specified in one or more flows and / or blocks

[0201] The above merely is the preferred embodiment of the present application, it should be pointed out that, for ordinary skilled in the art, without departing from the technical principles of the present application, can also make several improvements and variations, these improvements and variations also should be considered as the protection scope of the present application.

Claims

1. A method for evaluating the three-dimensional drape performance of a fabric, characterized in that, The method comprises the following steps: scanning the three-dimensional draping shape of the fabric, constructing a triangular mesh model, and dividing the triangular mesh model into a plurality of independent and non-intersecting triangles by using a triangulation algorithm according to the three-dimensional coordinates of all the vertices in the triangular mesh model; calculating the area of each triangle and the position data of the centroid of each triangle according to the three-dimensional coordinates of the vertices of each triangle, calculating the three-dimensional draping performance evaluation index of each triangle according to the position data of the centroid of each triangle, calculating the three-dimensional draping performance evaluation index of the fabric according to the three-dimensional draping performance evaluation index of each triangle and the area of each triangle, and evaluating the three-dimensional draping performance of the fabric through the three-dimensional draping performance evaluation index of the fabric; wherein, when the position data of the centroid is the lateral displacement and the longitudinal displacement of the centroid, the corresponding three-dimensional draping performance evaluation index is the draping displacement; and when the position data of the centroid is the longitudinal displacement of the centroid, the corresponding three-dimensional draping performance evaluation index is the draping potential; scanning the three-dimensional draping shape of the fabric, constructing a triangular mesh model comprises: cutting a circular fabric sample without creases, damage and flat edges within a preset distance from the edge of the fabric, cutting a positioning hole at the center of the fabric sample, and uniformly pasting a plurality of reflective marker points on the surface of the fabric sample; aligning the center of the fabric sample with the center of the upper clamping disc and the center of the lower clamping disc of the draping tester, making the positioning column of the lower clamping disc pass through the positioning hole of the fabric sample and the center hole of the upper clamping disc in turn, clamping the fabric sample, and making the fabric sample maintain natural three-dimensional draping without pulling; performing multi-angle scanning on the fabric sample to obtain complete three-dimensional data of the three-dimensional draping shape of the fabric sample; generating an initial triangular mesh model according to the complete three-dimensional data of the three-dimensional draping shape of the fabric sample; performing hole repair and non-manifold edge cleaning on the initial triangular mesh model to obtain a triangular mesh model.

2. The method of evaluating the three-dimensional drape performance of a fabric according to claim 1, wherein, The method for obtaining the 3D coordinates of all vertices in the triangular mesh model includes: taking the lower surface of the upper clamping disk as the reference plane, the center of the circle on the lower surface of the upper clamping disk as the origin, and the direction perpendicular to the reference plane upwards as... In the positive direction of the axis, with the horizontal projection plane of the fabric sample as... shaft and Construct a three-dimensional coordinate system in the orthogonal plane of the axes to obtain the three-dimensional coordinates of all vertices in the triangular mesh model.

3. The method of claim 1, wherein the fabric three-dimensional drape performance is evaluated by a fabric three-dimensional drape performance evaluation device. According to the three-dimensional coordinates of all the vertices in the triangular mesh model, the triangular mesh model is divided into a plurality of independent and non-intersecting triangles by using a triangulation algorithm, which comprises: importing the three-dimensional coordinates of all the vertices in the triangular mesh model into a programming software in the form of an array file, calling the triangulation algorithm, taking the imported three-dimensional coordinate array file of all the vertices as an input parameter, generating a plurality of independent and non-intersecting triangles, and simultaneously generating the position index of the vertices of each triangle in the three-dimensional coordinate array file.

4. The method of claim 1, wherein the fabric three-dimensional drape performance is evaluated by a fabric three-dimensional drape performance evaluation device. The calculation formula of the area of each triangle is: ； in, Indicates the first The area of ​​each triangle, , , They represent the first The cross product of the vectors of the triangles is axis, axis, Components of the axis, , , They represent the first The three vertices of a triangle Axis coordinates , , They represent the first The three vertices of a triangle Axis coordinates , , They represent the first The three vertices of a triangle Axis coordinates.

5. The method of claim 1, wherein the fabric three-dimensional drape performance is evaluated by a fabric three-dimensional drape performance evaluation device. The calculation formula of the lateral displacement of the centroid of each triangle is: ； wherein denotes the lateral displacement of the center of mass of the th triangle, denotes the radius of the upper clamping disc, , denotes the th triangle, axial coordinate of the center of mass of the th triangle; The calculation formula of the longitudinal displacement of the centroid of each triangle is: ； wherein denotes the longitudinal displacement of the centroid of the , , denotes the z-axis coordinate of the three vertices of the triangles, respectively.​​ 6. The method of claim 1, wherein the fabric three-dimensional drape performance is evaluated by a computer program. The calculation formula of the draping displacement of each triangle is: ； wherein, denotes the lateral displacement of the th triangle, , denotes the lateral displacement of the th triangle, respectively, The calculation formula of the draping displacement of the fabric is: ； wherein, represents the drape displacement of the fabric, represents the area of the first triangle, represents the total number of triangles.

7. The method of claim 1, wherein the fabric three-dimensional drape performance is evaluated by a fabric three-dimensional drape performance evaluation device. The calculation formula of the draping potential of each triangle is: ； wherein, denotes the longitudinal displacement of the centroid of the th triangle, denotes the longitudinal displacement of the centroid of the th triangle, denotes the gravitational acceleration; The calculation formula of the draping potential of the fabric is: ； wherein, denotes the drape potential of the fabric, denotes the area of the first triangle, denotes the total number of triangles.

8. A device for evaluating the three-dimensional draping properties of a fabric, characterized in that it comprises: The method comprises the following steps: a model construction module, configured to scan the three-dimensional draping shape of the fabric, construct a triangular mesh model, and divide the triangular mesh model into a plurality of independent and non-intersecting triangles by using a triangulation algorithm according to the three-dimensional coordinates of all the vertices in the triangular mesh model; The performance evaluation module is configured to calculate the area of each triangle and the position data of the centroid of each triangle according to the three-dimensional coordinates of the vertices of each triangle, calculate the three-dimensional draping performance evaluation index of each triangle according to the position data of the centroid of each triangle, calculate the three-dimensional draping performance evaluation index of the fabric according to the three-dimensional draping performance evaluation index of each triangle and the area of each triangle, and evaluate the three-dimensional draping performance of the fabric through the three-dimensional draping performance evaluation index of the fabric; When the position data of the centroid is the lateral displacement and the longitudinal displacement of the centroid, the corresponding three-dimensional draping performance evaluation index is the draping displacement; when the position data of the centroid is the longitudinal displacement of the centroid, the corresponding three-dimensional draping performance evaluation index is the draping potential. The scanning of the three-dimensional draping shape of the fabric and the construction of the triangular mesh model include: cutting a circular fabric sample without creases, damage and flat edges within a predetermined distance from the edge of the fabric, cutting a positioning hole at the center of the fabric sample, and uniformly pasting a plurality of reflective marker points on the surface of the fabric sample; aligning the center of the fabric sample with the center of the upper clamping disc and the center of the lower clamping disc of the draping tester, making the positioning column of the lower clamping disc pass through the positioning hole of the fabric sample and the center hole of the upper clamping disc in turn, clamping the fabric sample, and making the fabric sample maintain natural three-dimensional draping without pulling; performing multi-angle scanning on the fabric sample to obtain complete three-dimensional data of the three-dimensional draping shape of the fabric sample; generating an initial triangular mesh model according to the complete three-dimensional data of the three-dimensional draping shape of the fabric sample; performing hole repair and non-manifold edge cleaning on the initial triangular mesh model to obtain a triangular mesh model.

9. A computer device, comprising: It includes: a storage medium for storing a computer program; a processor for executing the computer program to implement the fabric three-dimensional draping performance evaluation method of any one of claims 1 to 7.

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