A method for reconstructing the front collar curve based on zero-point constraint of contact pressure

Abstract

This invention discloses a method for reconstructing a front neckline curve based on zero-point contact pressure constraints, comprising the following steps: establishing a basic neckline curve; proposing the definition and acquisition method of the "zero-point front neckline pressure"; converting the pressure distribution into a geometric offset (curve reconstruction) and establishing a formula relationship; partitioning different neck positions and assigning weight adjustments; obtaining the normal vector and combining it with the offset to obtain a refined neckline curve that better fits the human body; and outputting a template. This invention proposes the concept of the "zero-point front neckline pressure," which is the critical position where the neckline just contacts the skin without pressure. By acquiring contact pressure strain distribution data in the human neck region, a mapping relationship between pressure distribution and curve offset is established, and the original neckline curve is reconstructed by non-uniform normal offset to form a non-equidistant offset curve that conforms to the contact characteristics of the human body. Simultaneously, a weight adjustment mechanism is introduced to construct different partitions to achieve localized refined control and overall smooth transition.

Description

Technical Field

[0001] This invention belongs to the field of clothing structural design and digital pattern engineering technology, specifically involving a method for generating a front neckline curve driven by the pressure balance between the human body and clothing. Background Technology

[0002] In existing garment structural design, the construction of the front neckline curve typically relies on empirical ease and standard geometric arc forms, adjusted using neck circumference dimensions and empirical formulas. The human neck and clavicle region exhibit distinct three-dimensional undulations and soft tissue variations, resulting in uneven contact pressure distribution at different locations during garment wear. However, traditional neckline design methods fail to reflect these spatial distribution differences, often simplifying the neckline into a uniform curvature or equal ease structure, lacking the ability to finely control local areas.

[0003] This often leads to problems in actual wear: a feeling of pressure in the neckline and collarbone area due to excessive tightness; gaps or empty spaces in the upper collarbone area due to insufficient fit; and discomfort caused by uneven pressure and friction. These issues not only affect wearing comfort but also hinder the development of refined garment structural design. Existing neckline curves cannot match the optimal distribution of pressure on the human body, and there is a lack of a design method that can effectively translate contact information into a curved shape. Summary of the Invention

[0004] The purpose of this invention is to provide a method for reconstructing the front neckline curve based on zero-point contact pressure constraints. Addressing the shortcomings of existing technologies, this invention proposes the concept of a "zero-point front neckline pressure," which is the critical position where the neckline just contacts the skin without pressure. By acquiring contact pressure strain distribution data in the human neck region, a mapping relationship between pressure distribution and curve offset is established. The original neckline curve is then reconstructed using a non-uniform normal offset, forming a non-equidistant offset curve that conforms to human contact characteristics. Simultaneously, a weighted adjustment mechanism is introduced to construct different zones, achieving both localized fine-grained control and overall smooth transition.

[0005] To solve the above technical problems, the following technical solution is adopted:

[0006] A method for reconstructing the front collar curve based on zero-point contact pressure constraints, characterized by the following steps:

[0007] (1) Human neck region model construction: Obtain geometric morphological data of the human neck region. This data is obtained through a three-dimensional human body scanning device and is used to describe the spatial contour of the neck and clavicle region.

[0008] (2) Obtain pressure stress-strain data for the collar area;

[0009] (3) Define the zero point of contact pressure as the critical point at which the collar structure just contacts the skin of the front neck area without generating compressive stress when the human body is in a static standing state.

[0010] (4) Neckline curve adjustment based on contact pressure, including:

[0011] 4.1 Definition of curve offset;

[0012] 4.2 Regional partitioning and weight allocation;

[0013] 4.3 Setting the normal vector;

[0014] 4.4 Template output.

[0015] After optimization, in step (3), the contact pressure at any point on the neckline curve is defined as P(x). When a point satisfies the critical condition of the contact state changing from separation to compression, i.e., P(x0)→0, and the pressure gradient is not zero, the point is defined as the zero contact pressure point x0. This point represents the position where the neckline just contacts the human skin but has not yet produced obvious pressure, which is the balance point between comfort and fit. Considering the influence of the weight of the clothing fabric itself, the point is located by searching for a set of points that meet the conditions along the neckline curve, and the zero point is numerically determined by setting a pressure threshold of less than 0.1 kPa. .

[0016] After optimization, in step (4) 4.1, first set the neckline curve, set the original neckline curve as C0(s), the front neck point as (0,0), and discretize C0(s) into N key points: The coordinates of each point are: To construct the functional relationship with contact pressure, a normal vector is introduced. and offset Therefore, the neckline curve after pressure adjustment is: C(s) = C0(s) + · in This is the offset along the normal direction. This is the unit normal vector on the neckline curve.

[0017] After optimization, in step (4) 4.1, based on the human body-clothing contact pressure distribution, a mapping relationship between offset and pressure is established, so that the two are positively correlated and controlled; offset and contact pressure The pressure is proportional to the pressure; however, sudden changes in adjacent pressure points will cause changes in the offset, resulting in abrupt changes in the curve. Therefore, a pressure gradient term is established to add an additional offset when the pressure suddenly increases at a certain point. Finally, to ensure the generated curve is smooth, a curvature term is set. Therefore, the offset is defined as: in The contact pressure is distributed along the neckline curve. The direct effect of contact pressure on offset is characterized by a linear mapping between the comfortable neck pressure range of 1–5 kPa and the clothing ease allowance of 0–5 mm. =0.02 ∼ 0.05 mm / kPa; Used to regulate the influence of pressure gradients, the pressure field distribution was calibrated through 3D clothing simulation to determine its function. =0.01 ∼ 0.03 mm / kPa; Used to constrain curve smoothness, determined through numerical optimization by minimizing curvature fluctuations, with a value of [value missing]. =0.1 ~ 0.3 mm / kPa.

[0018] After optimization, in step (4) 4.1, to avoid excessive curve offset or structural abnormalities caused by local pressure fluctuations, the offset is adjusted. Perform constraint processing to ensure that it meets the requirements. ,in and These are the preset minimum and maximum allowable offset ranges, which are obtained through iterative fitting of multiple sets of simulation and trial pressure test data. The final offset is stable within the range of 0 to 6 mm.

[0019] After optimization, in step (4) 4.2, based on the geometric structural characteristics of the human neck and the distribution law of contact pressure, the neckline curve is divided into zones: zone A is the neck hollow region, zone B is the clavicle region, and zone C is the shoulder-neck transition region; based on the geometric characteristics and force differences of different zones of the neckline, a zone weighting coefficient is introduced to adjust the offset; the original offset... The weighted offset is Based on the results of human body fitting and 3D clothing simulation pressure tests, the area of ​​zone A is set to 0.2L, zone B to 0.38L, and zone C to 0.42L; a continuous weighting function based on arc length position is introduced, where s is a point on the curve. The arc length from the origin is defined by the region weight function as follows: in, , The partition assignment function is in piecewise linear form: Weight of each region Determined based on the normalized result of contact pressure; let the average contact pressure of the i-th region be... The overall average pressure is The regional weight can then be expressed as: The pressure distribution of each zone is obtained through 3D clothing simulation and fitting pressure test, and the zone weight is calculated based on the pressure distribution of different zones.

[0020] After optimization, in step (4) 4.3, the offset normal vector is obtained by calculating the tangent vector through the difference between adjacent points and rotating it by 90°. After normalization, it is used as the offset direction, and combined with the offset amount to realize the outward normal movement of the curve point; for the i-th point on the curve First, find the tangent vector between the points. Then rotate the tangent vector by 90° to obtain the normal vector. Finally, the normal vector is normalized to make it unit length. .

[0021] After optimization, in step (4) 4.4, after completing the optimization and reconstruction of the neckline curve, the final obtained curve C(s) is converted into two-dimensional pattern data that can be used for garment pattern making; through the parameter mapping method, the neckline curve in three-dimensional space is projected onto the garment pattern plane coordinate system to generate the corresponding two-dimensional outline.

[0022] First, using the neckline curve arc length parameter s as a unified variable, the optimized 3D curve is discretized to obtain a series of ordered point sets. Subsequently, based on the unfolding rules of the garment pattern, the front pattern plane was selected as the reference plane, and coordinate transformation and projection processing were performed on each point to map the three-dimensional coordinates into two-dimensional coordinates. To reduce the impact of spatial curvature on unfolding accuracy, the arc length must be kept consistent during projection, i.e., satisfying... Spline curve fitting is performed on the projected 2D point set to obtain a continuous and smooth neckline outline, which is then aligned and spliced ​​with the original template.

[0023] The above technical solution has the following beneficial effects:

[0024] This invention presents a parametric reconstruction method for neckline curves based on the pressure distribution between the human body and clothing, enabling a shift from empirical design to quantitative design. By introducing zero-pressure points, zone weights, and continuous offset functions, it achieves adaptive adjustment in different areas, improving neckline fit and wearing comfort while ensuring curve continuity and structural stability. This method demonstrates good feasibility and potential for widespread application. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings:

[0026] Figure 1 Diagram showing the pressure exerted on the human body by clothing;

[0027] Figure 2 This is the original neckline curve diagram;

[0028] Figure 3 A zoning diagram of the neckline area;

[0029] Figure 4 A diagram showing the difference in pressure experienced by different neckline areas;

[0030] Figure 5 The diagram shows the changes in the neckline curve after adjustment;

[0031] Figure 6 This is a comparison image of the template before and after correction. Detailed Implementation

[0032] This invention aims to provide a method for reconstructing the front neckline curve based on zero-point contact pressure constraints. It proposes the concept of a "zero-point front neckline pressure," which is the critical position where the neckline just contacts the skin without pressure. By acquiring contact pressure strain distribution data in the human neck region, a mapping relationship between pressure distribution and curve offset is established. The original neckline curve is then reconstructed using a non-uniform normal offset, forming a non-equidistant offset curve that conforms to human contact characteristics. Simultaneously, a weight adjustment mechanism is introduced to construct different zones, achieving both local fine-grained control and a smooth overall transition.

[0033] The technical solution of the present invention will be described in detail below with reference to specific embodiments:

[0034] A method for reconstructing the front collar curve based on zero-point contact pressure constraints includes the following steps:

[0035] 1. Construction of a human neck region model

[0036] A non-contact scanning method using a 3D human body scanner was employed to scan the upper body of the subjects. Under conditions of natural standing and a neutral head posture, 3D point cloud data including the neck, clavicle, and shoulder-neck transition area was acquired. The raw point cloud was then preprocessed with denoising, outlier removal, and hole filling to improve data integrity and accuracy. A surface reconstruction algorithm was then used to convert the discrete point cloud into a continuous 3D mesh model, constructing an initial geometric model of the human neck region. Based on this, the spatial scope of the model was defined according to human anatomical structure, with the base of the neck as the upper boundary, the lower edge of the clavicle as the lower boundary, and the vicinity of the acromion as the left and right boundaries, to extract the target area model related to neckline design.

[0037] 2. Obtain pressure stress and strain data in the collar area.

[0038] The completed 3D model of the human neck is imported into clothing simulation software, and a corresponding neckline structure model is established, setting the fabric thickness, elastic modulus, and bending stiffness. Subsequently, collision detection and contact solving algorithms are used to simulate the fit between the clothing and the human body. Static equilibrium calculations are performed under gravity and boundary constraints to obtain the contact pressure distribution between the neckline area and the human body surface (e.g., ...). Figure 1(As shown). The pressure is mapped onto the human body surface in the form of a continuous field and extracted as a one-dimensional function 𝑃(s) along the neckline curve.

[0039] 3. Definition of zero point of contact pressure

[0040] To achieve precise control of the neckline structure, the concept of a zero-pressure contact point is introduced. The contact pressure at any point on the neckline curve is defined as P(x). When a point satisfies the critical condition for the transition from separation to compression (P(x0)→0) and the pressure gradient is not zero, this point is defined as the zero-pressure contact point x0. This point represents the position where the neckline just contacts the skin but before significant pressure is generated; it is a balance point between comfort and fit. Considering the influence of the fabric's weight, the zero-pressure point is located by searching for a set of points that meet the conditions along the neckline curve. A pressure threshold of less than 0.1 kPa is set for numerical determination of the zero-pressure point.

[0041] .

[0042] 4. Neckline curve adjustment based on contact pressure, including:

[0043] 4.1 Definition of Curve Offset

[0044] To achieve adaptive adjustment of the neckline curve, it is necessary to establish a functional relationship between the curve offset and the contact pressure. For example... Figure 2 As shown, let the original neckline curve (1 / 2 of the front neckline) be C0(s), and the front neck point be (0,0). Discretize C0(s) into N key points, i.e.

[0045]

[0046] The coordinates of each point are: To construct the functional relationship with contact pressure, a normal vector is introduced. and offset Therefore, the curve after pressure adjustment is

[0047] C(s) = C0(s) + ·

[0048] in This is the offset along the normal direction. This is the unit normal vector on the neckline curve.

[0049] Based on the pressure distribution of the human body in contact with clothing, a mapping relationship between offset and pressure is established, creating a positive correlation control mechanism. Specifically, areas with higher contact pressure reduce pressure by increasing offset, while areas with lower pressure reduce offset to enhance fit. Therefore, offset is primarily related to contact pressure. The pressure is proportional; however, sudden changes in adjacent pressure points will cause changes in the offset, resulting in abrupt changes in the curve and phenomena such as strangulation. Therefore, a pressure gradient term needs to be established to add an additional offset when the pressure suddenly increases at a certain point. Finally, to ensure the generated curve is smooth, a curvature term is set. Therefore, the offset is defined as:

[0050]

[0051] in The contact pressure is distributed along the neckline curve, where, The direct effect of contact pressure on offset is characterized by a linear mapping between the comfortable pressure range of the human neck (1 – 5 kPa) and clothing ease (0 – 5 mm). =0.02 ∼ 0.05 mm / kPa; Used to regulate the influence of pressure gradients, the pressure field distribution was calibrated through 3D clothing simulation to determine its function. =0.01 ~ 0.03 mm / kPa, to suppress sudden changes in local pressure; Used to constrain curve smoothness, determined through numerical optimization by minimizing curvature fluctuations, with a value of [value missing]. =0.1 ~ 0.3 mm / kPa.

[0052] To avoid excessive curve offset or structural anomalies caused by local pressure fluctuations, the offset is... Perform constraint processing to ensure that it meets the requirements. ,in and These are the preset minimum and maximum allowable offset ranges, which are obtained through iterative fitting of multiple sets of simulation and trial pressure test data, and the final offset is stable within the range of 0 to 6 mm.

[0053] 4.2 Regional partitioning and weight allocation

[0054] Based on the geometric characteristics of the human neck and the distribution of contact pressure, the neckline curve is divided into sections, such as... Figure 3 As shown: Area A is the neck hollow area, with obvious curved depressions and high contact sensitivity; Area B is the clavicle area, with large surface undulations, and is easily compressed by clothing; Area C is the shoulder-neck transition area, with gentle geometric changes, mainly serving as a connection and transition, but is easily affected by the weight of clothing.

[0055] Therefore, the offset is further optimized based on the geometric characteristics and stress differences in different areas of the neckline (such as...). Figure 4 As shown), a regional weighting coefficient is introduced to adjust the offset; the original offset The weighted offset is

[0056] Based on multiple sets of human body fitting and 3D clothing simulation pressure test results, the half arc length L of the front neckline was calibrated by region. The results show that the neck hollow region (region A) occupies approximately 0.2L, the clavicle region (region B) occupies approximately 0.38L, and the shoulder-neck transition region (region C) occupies approximately 0.42L.

[0057] Based on the above partitioning, to avoid abrupt changes in weights, a continuous weight function based on arc length position is introduced. s is a point on the curve. Given the arc length from the origin, the region weight function is defined as follows:

[0058] in, , The partition assignment function is in piecewise linear form:

[0059] Weight of each region Determined based on the normalized result of contact pressure; let the average contact pressure of the i-th region (A, B, C) be... The overall average pressure is The regional weight can then be expressed as:

[0060] The pressure distribution in each zone was obtained through 3D clothing simulation and fitting pressure testing, as shown in Table 1.

[0061] Table 1 Pressure distribution in different zones

[0062] area Corresponding pressure color Pressure range (kPa) A Blue-Green 0.2-0.35 B Green-Yellow 0.5-0.75 C Blue-Green 0.1-0.3

[0063] Therefore, the regional weights are calculated based on the pressure distribution of different zones.

[0064] Table 2. Regional weights of different partitions and adjusted results

[0065] area Regional weight A 0.8 B 1.56 C 0.64

[0066] 4.3 Setting the Normal Vector

[0067] The offset normal vector is obtained by calculating the tangent vector through the difference between adjacent points and rotating it by 90°. After normalization, it serves as the offset direction and, combined with the offset amount, achieves the outward normal movement of the curve point. Specifically, for the i-th point on the curve... First, find the tangent vector between the points.

[0068]

[0069] Then rotate the tangent vector by 90° to obtain the normal vector.

[0070] Finally, the normal vector is normalized to make it unit length. .

[0071] The curve changes after adjustment as follows Figure 5 As shown.

[0072] 4.4 Sample Output

[0073] After optimizing and reconstructing the neckline curve, the final curve C(s) is converted into two-dimensional pattern data that can be used for garment pattern making. Specifically, the neckline curve in three-dimensional space is projected onto the garment pattern plane coordinate system using a parametric mapping method to generate the corresponding two-dimensional contour line.

[0074] In the implementation process, the curve arc length parameter s is first used as a unified variable to perform discrete sampling on the optimized 3D curve, resulting in a series of ordered point sets. Subsequently, based on the unfolding rules of the garment pattern, the front piece pattern plane was selected as the reference plane, and coordinate transformation and projection processing were performed on each point to map the three-dimensional coordinates into two-dimensional coordinates. To reduce the impact of spatial curvature on unfolding accuracy, the arc length must be kept consistent during projection, i.e., the following must be satisfied:

[0075]

[0076] This ensures that the length of the unfolded curve is consistent with the original structure, avoiding deviations in neckline size.

[0077] Furthermore, spline curve fitting is performed on the projected two-dimensional point set to obtain a continuous and smooth neckline outline, which is then aligned and spliced ​​with the original template.

[0078] Through the above steps, the conversion from a three-dimensional pressure-driven optimization curve to a two-dimensional garment pattern was achieved, and the comparison before and after pattern correction is shown in the figure. Figure 6 As shown.

[0079] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of the present invention.

Claims

1. A method for reconstructing the front collar curve based on zero-point constraint of contact pressure, characterized in that... The steps include: (1) constructing a model of the human neck region and obtaining geometric morphological data of the human neck region. This data is obtained through a three-dimensional human body scanning device and is used to describe the spatial contour of the neck and clavicle region; (2) obtaining pressure stress and strain data of the collar area; (3) defining the zero point of contact pressure as the critical point where the collar structure just contacts the skin of the front neck region without generating compressive stress when the human body is in a static standing state. (4) Collar curve adjustment based on contact pressure, including: 4.1 Definition of curve offset; 4.2 Weight allocation for regional partitioning; 4.3 Setting of normal vector; 4.4 Template output.

2. The method for reconstructing the front collar curve based on zero-point constraint of contact pressure according to claim 1, characterized in that: In step (1), a three-dimensional human body scanning device is used to perform a non-contact scan of the subject's upper body. Under the condition of standing naturally and keeping the head in a neutral posture, three-dimensional point cloud data including the neck, clavicle and shoulder-neck transition area are obtained. Then, the original point cloud is preprocessed by denoising, outlier removal and hole filling. The discrete point cloud is converted into a continuous three-dimensional mesh model by a surface reconstruction algorithm to construct the initial geometric model of the human neck area. On this basis, the spatial range of the model is limited according to the human anatomical structure, with the neck root as the upper boundary, the lower edge of the clavicle as the lower boundary, and the vicinity of the acromion as the left and right boundaries, and the target area model related to the neckline design is extracted.

3. The method for reconstructing the front collar curve based on zero-point constraint of contact pressure according to claim 1, characterized in that: In step (2), the completed human neck area model is imported into the clothing simulation software, and a corresponding neckline structure model is established, and the fabric thickness, elastic modulus and bending stiffness are set. Subsequently, the fit between clothing and human body is simulated by collision detection and contact solution algorithms. Static equilibrium calculation is performed under gravity and boundary constraints to obtain the contact pressure distribution between the neckline area and the human body surface. The pressure is mapped onto the human body surface in the form of a continuous field and extracted as a one-dimensional function 𝑃(s) along the neckline curve.

4. The method for reconstructing the front collar curve based on zero-point constraint of contact pressure according to claim 1, characterized in that: In step (3), the contact pressure at any point on the neckline curve is defined as P(x). When a point satisfies the critical condition of the contact state transitioning from separation to compression, i.e., P(x0)→0, and the pressure gradient is not zero, this point is defined as the zero contact pressure point x0. This point represents the position where the neckline just contacts the human skin but has not yet produced significant pressure, representing a balance between comfort and fit. Considering the influence of the weight of the clothing fabric itself, the zero point is located by searching for a set of points that meet the conditions along the neckline curve. A pressure threshold of less than 0.1 kPa is set to numerically determine the zero point. .

5. The method for reconstructing the front collar curve based on zero-point constraint of contact pressure according to claim 1, characterized in that: In step (4) 4.1, first set the neckline curve, set the original neckline curve as C0(s), the front neck point is (0,0), and discretize C0(s) into N key points: The coordinates of each point are: To construct the functional relationship with contact pressure, a normal vector is introduced. and offset Therefore, the neckline curve after pressure adjustment is as follows: C(s) = C0(s) + · in This is the offset along the normal direction. This is the unit normal vector on the neckline curve.

6. The method for reconstructing the front collar curve based on zero-point constraint of contact pressure according to claim 5, characterized in that: Step (4) 4.1 establishes a mapping relationship between offset and pressure based on the human-clothing contact pressure distribution, creating a positive correlation control mechanism between the two; offset and contact pressure The pressure is proportional to the pressure; however, sudden changes in adjacent pressure points will cause changes in the offset, resulting in abrupt changes in the curve. Therefore, a pressure gradient term is established to add an additional offset when the pressure suddenly increases at a certain point. Finally, to ensure the generated curve is smooth, a curvature term is set. Therefore, the offset is defined as: in The contact pressure is distributed along the neckline curve. The direct effect of contact pressure on offset is characterized by a linear mapping between the comfortable neck pressure range of 1–5 kPa and the clothing ease allowance of 0–5 mm. =0.02 ∼ 0.05 mm / kPa; Used to regulate the influence of pressure gradients, the pressure field distribution was calibrated through 3D clothing simulation to determine its function. =0.01 ∼ 0.03 mm / kPa; Used to constrain curve smoothness, determined through numerical optimization by minimizing curvature fluctuations, with a value of [value missing]. =0.1 ~ 0.3 mm / kPa.

7. The method for reconstructing the front collar curve based on zero-point constraint of contact pressure according to claim 6, characterized in that: In step (4) 4.1, to avoid excessive curve offset or structural abnormalities caused by local pressure fluctuations, the offset is adjusted. Perform constraint processing to ensure that it meets the requirements. ,in and These are the preset minimum and maximum allowable offset ranges, which are obtained through iterative fitting of multiple sets of simulation and trial pressure test data. The final offset is stable within the range of 0 to 6 mm.

8. The method for reconstructing the front collar curve based on zero-point constraint of contact pressure according to claim 6, characterized in that: In step (4) 4.2, based on the geometric characteristics of the human neck and the distribution of contact pressure, the neckline curve is divided into zones: Zone A is the cervical fossa region, Zone B is the clavicle region, and Zone C is the shoulder-neck transition region; based on the geometric characteristics and force differences of different zones of the neckline, a zone weighting coefficient is introduced to adjust the offset; the original offset... The weighted offset is Based on the results of human body fitting and 3D clothing simulation pressure tests, the area of ​​zone A is set to 0.2L, zone B to 0.38L, and zone C to 0.42L; a continuous weighting function based on arc length position is introduced, where s is a point on the curve. The arc length from the origin is defined by the region weight function as follows: in, , The partition assignment function is in piecewise linear form: Weight of each region Determined based on the normalized result of contact pressure; let the average contact pressure of the i-th region be... The overall average pressure is The regional weight can then be expressed as: The pressure distribution of each zone is obtained through 3D clothing simulation and fitting pressure test, and the zone weight is calculated based on the pressure distribution of different zones.

9. The method for reconstructing the front collar curve based on zero-point constraint of contact pressure according to claim 5, characterized in that: In step (4) 4.3, the offset normal vector is obtained by calculating the tangent vector through the difference between adjacent points and rotating it by 90°. After normalization, it is used as the offset direction and combined with the offset amount to realize the outward normal movement of the curve point; for the i-th point on the curve First, find the tangent vector between the points. Then rotate the tangent vector by 90° to obtain the normal vector. Finally, the normal vector is normalized to make it unit length. .

10. The method for reconstructing the front collar curve based on zero-point constraint of contact pressure according to claim 5, characterized in that: In step (4) 4.4, after completing the optimization and reconstruction of the neckline curve, the final obtained curve C(s) is converted into two-dimensional pattern data that can be used for garment pattern making; the neckline curve in three-dimensional space is projected onto the garment pattern plane coordinate system through the parameter mapping method to generate the corresponding two-dimensional contour line; firstly, the neckline curve arc length parameter s is used as a unified variable to perform discrete sampling on the optimized three-dimensional curve to obtain a series of ordered point sets. ; Subsequently, based on the unfolding rules of the garment pattern, the front pattern plane was selected as the reference plane, and coordinate transformation and projection processing were performed on each point to map the three-dimensional coordinates into two-dimensional coordinates. To reduce the impact of spatial curvature on unfolding accuracy, the arc length must be kept consistent during projection, i.e., satisfying... Spline curve fitting is performed on the projected 2D point set to obtain a continuous and smooth neckline outline, which is then aligned and spliced ​​with the original template.

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