Automobile modeling geometry model automatic repairing method, device and equipment

Abstract

This application relates to an automatic repair method, apparatus, and device for automotive styling geometric models. The method includes: refining an automotive product sketch using CAD software to accurately determine the dimensions and positions of each component, thus constructing an automotive styling geometric model; obtaining geometric information from the automotive styling geometric model; the geometric information includes the model's three-dimensional surfaces, three-dimensional curves, three-dimensional points, and the midlines and points defined on each three-dimensional surface in the topological relationships; discretizing the continuous geometry represented by the three-dimensional curves and surfaces to construct a common representation of the continuous geometry, discrete geometry, and topological relationships of the geometric model; and, based on the common representation, repairing missing automotive styling data and accuracy defects according to three types of geometric entities: surfaces, curves, and geometric points, to obtain a repaired automotive styling geometric model. This method can improve the efficiency of automotive geometric model repair.

Description

Technical Field

[0001] This application relates to the field of automotive model repair technology, and in particular to an automatic repair method, apparatus and equipment for automotive geometric models. Background Technology

[0002] With the increasing popularity of electric vehicles and the growing demand for longer battery life, designing cars with lower drag coefficients and better performance has become a common requirement for major manufacturers. A research study on automotive styling conducted by the Italian company Pininfarina in collaboration with the Italian National Institute of Scientific Research (INSERM) indicates that future automotive styling will be primarily aerodynamic. Starting from aerodynamics, the body shape will be determined through experimentation to achieve excellent aerodynamic characteristics while meeting the stringent requirements of various usage and manufacturing processes. Therefore, improving and enhancing aerodynamic characteristics in automotive styling has extremely important practical significance.

[0003] There are two main methods for aerodynamic performance analysis of automotive styling: wind tunnel testing and numerical simulation using Computational Fluid Dynamics (CFD). Traditional wind tunnel testing generally yields highly reliable results, but it has many limitations, such as high cost, long cycle time, and the need to create a series of clay models. Furthermore, wind tunnel testing can only measure velocity, pressure, and temperature values ​​at limited cross-sections and locations, making it impossible to obtain detailed information at any point in the entire flow field. In contrast, while CFD testing is less precise than wind tunnel testing, it overcomes almost all of its limitations. CFD allows for convenient and flexible modification of initial conditions, boundary conditions, and geometric boundaries, and provides detailed information at any point in the entire flow field. This allows for analysis of the flow field near the vehicle, enabling feedback adjustments to the vehicle body, such as improving the front styling, increasing the tilt angle, reducing the front edge height, improving the underbody styling, and increasing the underbody velocity. Using CFD analysis can significantly shorten the aerodynamic performance design cycle of vehicle models, making optimization faster and more effective.

[0004] CFD analysis requires the generation of a mesh from the geometric model representing the design before numerical calculations can begin. Mesh generation places very high demands on the accuracy and completeness of the geometric model. Due to the diverse sources of the initial input automotive geometric model, these requirements are often not considered or are difficult to foresee during the design process. Therefore, before mesh generation, the automotive geometric model needs to be repaired and simplified according to the needs of the CFD calculation mesh.

[0005] However, currently, due to potential defects in the geometric data of certain components in the geometric model representing the car's styling during the design and manufacturing process, and the loss of geometric information that may occur when converting data between different design software, the mesh generated based on the geometric model produced in the styling design stage becomes a "dirty geometry" with "noise." It generally cannot directly generate a mesh suitable for subsequent CFD analysis, thus requiring geometric model repair. Geometric model repair typically involves a large amount of tedious manual work, often consuming a significant amount of time. Summary of the Invention

[0006] Therefore, it is necessary to provide an automatic repair method and device for automotive geometric models that can improve the repair efficiency of automotive geometric models, addressing the aforementioned technical problems.

[0007] An automatic repair method for automotive styling geometric models, the method comprising:

[0008] Obtain the automotive product sketches created during the concept design phase;

[0009] CAD software is used to refine the sketches of automotive products, accurately determine the dimensions and positions of each component, and construct a geometric model of the automotive shape.

[0010] Obtain the geometric information of the model from the automotive styling geometric model; the geometric information includes the three-dimensional surfaces, three-dimensional curves, three-dimensional points, and the midlines and points defined on each three-dimensional surface in the topological relationship of the geometric model;

[0011] Discretize the continuous geometry represented by three-dimensional curves and three-dimensional surfaces to construct a common representation of continuous geometry, discrete geometry, and topological relationships in the geometric model;

[0012] Based on common representations, missing data and accuracy defects in automotive styling data are repaired for three types of geometric entities: surfaces, curves, and geometric points, resulting in a repaired automotive styling geometric model.

[0013] In one embodiment, the continuous geometry represented by three-dimensional curves and three-dimensional surfaces is discretized to construct a geometric model for joint characterization, including:

[0014] Discretize the continuous geometry, determine the position of the discrete segmentation point of the continuous geometry in the parameter domain, use the node vector defined by NURBS of the three-dimensional curve or three-dimensional surface as the parameter coordinate of the initial discrete point, and then determine whether interpolation is needed to meet the accuracy requirements by the deviation distance between adjacent discrete points, so as to obtain the discrete representation of the curve or surface.

[0015] The midline of a surface is constructed using a discretized curve representation.

[0016] In one embodiment, the process of calculating the deviation distance between discrete points includes:

[0017] The specific method for calculating the deviation distance dev between three consecutive discrete points p1, p2, and p3 is as follows:

[0018]

[0019] In one embodiment, the midline of a surface is constructed using a curve discretization representation, including:

[0020] If curve C and surface S have a topological relationship, then the three-dimensional discrete points in the discrete representation of curve C are also located on surface S. The corresponding coordinates of the three-dimensional discrete points of curve C in the parameter space are found through the parametric equation of curve S to form the midline of the surface.

[0021] In one embodiment, missing data repair for vehicle styling includes topological loop repair of surfaces, curve repair of topological edges, and corresponding geometric point repair of vertices; accuracy defect repair includes geometric accuracy defect repair and topological accuracy defect repair; based on common representations, missing data repair and accuracy defect repair for vehicle styling are performed according to three types of geometric entities: surfaces, curves, and geometric points, including:

[0022] Based on common representations, missing automotive styling data is repaired by classifying them into three types of geometric entities: surfaces, curves, and geometric points. Four intersecting surface midlines and topological edges are established at the surface boundaries in parameter space to form a topological loop, thus completing the topological loop repair of the surface.

[0023] The topological edge is reconstructed using the surface midline corresponding to the surface and the non-degenerate closed smooth surface. If the surface midline is located at the boundary of the parameter space, the curve where the boundary is located is extracted according to the equation of the non-degenerate closed smooth surface, and the extracted curve is segmented by the parameter coordinate interval of the surface midline. If the surface midline is located inside the parameter space, the discrete points of the surface midline are used as the initial point sequence. The deviation distance between adjacent discrete points is used to determine whether interpolation is needed to meet the accuracy requirements. If the accuracy requirements are met, the parameter coordinates of the discrete points are converted into three-dimensional coordinates by the equation of the non-degenerate closed smooth surface. A first-order non-degenerate closed smooth curve is established with the discrete points as control vertices to complete the curve repair of the topological edge.

[0024] The missing geometric points are reconstructed and repaired using the start and end coordinates of the corresponding topological edge discrete representation, resulting in the repaired geometric points.

[0025] In one embodiment, it is determined whether there is a precision defect on the surface. If there is a precision defect on the surface, the precision defect type is detected based on the intersection of the surfaces, and the precision defect is repaired based on the precision defect type.

[0026] Based on the continuity of the centerlines of adjacent surfaces, the curve is inspected for accuracy defects, and the curve accuracy defects are repaired according to the type of accuracy defect.

[0027] In one embodiment, the presence of precision defects on the surface is determined. If precision defects are found, the surface is subjected to precision defect type detection based on its intersecting properties, and precision defect repair is performed based on the precision defect type, including:

[0028] Find two adjacent topological surfaces and two topological edges at their intersection lines based on the topological relationships. Calculate the Hausdorff distance between the geometric curves corresponding to the two topological edges. Determine the curve coincidence based on the Hausdorff distance. Determine whether there are any accuracy defects on the surface based on the curve coincidence.

[0029] If the surface has a precision defect, find the intersection of the two surfaces with the precision defect. If the surfaces have an intersection line, it is a topological precision defect. The obtained intersection line is used as a new topological edge, and the corresponding 3D curve data is updated. If there is no intersection line, it is a geometric precision defect. The surface is repaired by extension or filling.

[0030] In one embodiment, the curve is subjected to precision defect detection based on the continuity of the centerlines of adjacent surfaces, and the curve precision defect is repaired according to the type of precision defect, including:

[0031] The intersection of the topologically connected surface midlines is calculated. If an actual intersection point exists and the distance between the intersection point and the common endpoint is greater than the tolerance, the new intersection point is taken as the endpoint of the surface midline. If the distance between the intersection point and the common endpoint is less than the tolerance, it remains unchanged. If no actual intersection point exists, but the topologically connected surface midlines have a common endpoint or an actual intersection point with other surface midlines, the storage locations of the corresponding surface midlines are swapped, and the actual connected surface midlines are connected to achieve topological accuracy defect repair.

[0032] The intersection of the topologically connected surface midlines is calculated. If there is an actual intersection point and the distance between the intersection point and the common endpoint is equal to the tolerance, or if there is no actual intersection point and the topologically connected surface midlines do not have a common endpoint or actual intersection point with other surface midlines, then the curve is repaired with geometric precision. The surface midline is created with the endpoint of the gap, and the geometric solid curve is reconstructed using the surface midline corresponding to the topological edge and the non-degenerate closed smooth surface to achieve the repair of the geometric precision defect of the curve.

[0033] When the distance between the coordinates of a geometric point and the start and end points of the curve is greater than the tolerance, it is determined to be a geometric point precision defect. The erroneous geometric point is deleted, and the missing geometric point is reconstructed and repaired using the start and end coordinates of the corresponding topological edge discrete representation, so as to obtain the repaired geometric point.

[0034] An automatic repair device for automotive styling geometric models, the device comprising:

[0035] A module for constructing automotive styling geometric models is used to obtain automotive product sketches created during the conceptual design phase. CAD software is then used to refine these sketches, precisely determining the dimensions and positions of each component to construct the automotive styling geometric model.

[0036] The geometric information acquisition module is used to acquire the geometric information of the model from the automotive styling geometric model; the geometric information includes the three-dimensional surfaces, three-dimensional curves, three-dimensional points, and the midlines and points defined on the three-dimensional surfaces in the topological relationship of the geometric model.

[0037] The discretization module is used to discretize the continuous geometry represented by 3D curves and 3D surfaces to construct a common representation of continuous geometry, discrete geometry, and topological relationships in the geometric model;

[0038] The defect repair module is used to repair missing and precision defects in automotive styling data according to the common characteristics of three types of geometric entities: surfaces, curves, and geometric points, to obtain the repaired automotive styling geometric model.

[0039] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program performing the following steps:

[0040] Obtain the automotive product sketches created during the concept design phase;

[0041] CAD software is used to refine the sketches of automotive products, accurately determine the dimensions and positions of each component, and construct a geometric model of the automotive shape.

[0042] Obtain the geometric information of the model from the automotive styling geometric model; the geometric information includes the three-dimensional surfaces, three-dimensional curves, three-dimensional points, and the midlines and points defined on each three-dimensional surface in the topological relationship of the geometric model;

[0043] Discretize the continuous geometry represented by three-dimensional curves and three-dimensional surfaces to construct a common representation of continuous geometry, discrete geometry, and topological relationships in the geometric model;

[0044] Based on common representations, missing data and accuracy defects in automotive styling data are repaired for three types of geometric entities: surfaces, curves, and geometric points, resulting in a repaired automotive styling geometric model.

[0045] The aforementioned method, apparatus, and equipment for automatically repairing automotive styling geometric models establish a common representation based on continuous geometry, discrete geometry, and topological relationships during the reading stage of the automotive geometric model for CFD analysis. This greatly optimizes the processing flow for geometric repair and feature simplification of automotive geometric models. Furthermore, addressing the issue that automotive styling cannot be directly used for aerodynamic design analysis, the method repairs missing data and accuracy defects in automotive styling based on the common representation, categorizing the data into three types of geometric entities: surfaces, curves, and geometric points. This automates the repair of the automotive geometric model to meet mesh generation requirements, avoiding the time-consuming and laborious manual repair process and significantly improving the repair efficiency of automotive styling geometric models. Attached Figure Description

[0046] Figure 1 This is a flowchart illustrating an automatic repair method for a car styling geometric model in one embodiment;

[0047] Figure 2 This is a geometric model diagram of the car's shape in one embodiment;

[0048] Figure 3 This is a schematic diagram of continuous geometry, discrete geometry, and topological relationships in a common representation method for automobile styling in one embodiment.

[0049] Figure 4 This is a schematic diagram of the post-discretization results on a continuous NURBS surface in another embodiment;

[0050] Figure 5 This is a schematic diagram illustrating the topology reconstruction process for a surface with topological defects in one embodiment.

[0051] Figure 6 This is a schematic diagram illustrating the classification of surface accuracy defects in one embodiment;

[0052] Figure 7 This is a schematic diagram of the curve accuracy defect classification and repair process in one embodiment;

[0053] Figure 8 This is a structural block diagram of an automatic repair device for automotive styling geometric models in one embodiment;

[0054] Figure 9 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0056] In one embodiment, such as Figure 1 As shown, an automatic repair method for automotive styling geometry models is provided, including the following steps:

[0057] Step 102: Obtain the automotive product sketches created during the conceptual design phase; refine the automotive product sketches using CAD software, accurately determining the dimensions and positions of each component to construct the automotive styling geometric model.

[0058] The process of using CAD software to refine automotive product sketches and accurately determine the dimensions and positions of each component to construct an automotive geometric model is existing technology and will not be elaborated upon in this application.

[0059] Step 104: Obtain the geometric information of the model from the automotive styling geometric model; the geometric information includes the three-dimensional surfaces, three-dimensional curves, three-dimensional points, and the midlines and points defined on each three-dimensional surface in the topological relationship of the geometric model.

[0060] In geometric models, topological entities all have corresponding geometric entities. For example, a topological surface represents the region of a corresponding 3D surface after one or more trimmings. This region is generally called a trimmed surface. The effective parameter domain after trimming is usually a part of the parameter domain of the original surface. The trimmed surface can accurately represent the defined region. Therefore, a topological surface usually needs to contain a parametric equation representing the original surface and a topological loop that defines the region. A topological surface must contain an outer topological loop, which defines the outermost contour boundary of the region. It may also contain one or more inner topological loops, representing the void regions within the region. Each topological loop consists of a series of topological edges. All topological edges in a single topological loop connect end-to-end to form a closed loop. Topological edges are components of the boundaries of topological surfaces and also serve as the links connecting topological surfaces. They have corresponding geometric entity curves defined in 3D space. These curves lie on the surface, and therefore have a corresponding 2D surface midline in the surface parameter space. Topological points are the boundaries of topological lines, and they have corresponding geometric entity points defined in 3D space. Topological points or edges on different surfaces may correspond to the same vertex or curve in three-dimensional space.

[0061] In automotive styling design, the Non-Uniform Rational B-Spline (NURBS) method is widely used to describe surfaces and curves. A NURBS curve p(u) is defined by its order k and weight factor ω. i (i = 0, 1, ..., n), control vertex d i (i = 0, 1, ..., n) and node vector U = [u0, u1, ..., u n+k+1 The nodal vectors define the parameter domain of the curve and also define the basis functions N in the parametric equations. i,k The definition has been established. The surface p(u,v) is a generalization of the definition of a curve, given two directional parameters, the order k in the U direction and the order l in the V direction, and the weight factor ω.ij With control vertex d ij (i = 0, 1, ..., m; j = 0, 1, ..., n), U-direction node vector U = [u0, u1, ..., u m+k+1 ] and the node vector V = [v0, v1, ..., v] n+l+1 The parametric equations of its NURBS curve and surface are as follows:

[0062] curve:

[0063] Curved surface:

[0064] The surface parameter space refers to the parameter domain of a three-dimensional surface, i.e., (u,v), where u0≤u≤u. m+k+1 v0≤v≤v n+l+1 The coordinates of any point (u', v') in the surface parameter space in three-dimensional space are (p... x (u',v'),p y (u',v'),p z (u',v')).

[0065] by Figure 2 For example, the geometric model parameters of the car shape are obtained, and the maximum mesh unit size L is specified to assist in geometric repair. The geometric information in the car shape includes three-dimensional surfaces (number, order, weight factor, control vertex, node vector), three-dimensional curves (number, order, weight factor, control vertex, node vector), and three-dimensional points (number, three-dimensional coordinates) in the geometric entity, as well as the face midline (corresponding three-dimensional curve number) and face points (corresponding three-dimensional point number) defined on each three-dimensional surface in the topological relationship.

[0066] Step 106: Discretize the continuous geometry represented by the three-dimensional curves and three-dimensional surfaces to construct a common representation of the continuous geometry, discrete geometry, and topological relationships of the geometric model.

[0067] Discretizing the continuous geometry represented by curves and surfaces yields the corresponding discrete representation, thus constructing a common representation of continuous geometry, discrete geometry, and topological relationships, such as... Figure 3 As shown. The steps for constructing the discrete representation are as follows:

[0068] 2.1.1 Discretize the continuous geometry and determine the positions of the discrete points in the parameter domain. Use the node vectors defined by NURBS for the curve or surface as the parametric coordinates of the initial discrete points. Then, determine whether interpolation is needed to meet accuracy requirements by using the deviation distance between adjacent discrete points. The result of discretizing the surface in the parameter domain is as follows: Figure 4 As shown. The specific method for calculating the deviation distance dev between three consecutive discrete points p1, p2, and p3 is as follows:

[0069]

[0070] If dev < μ, it indicates that the accuracy requirement is met, where μ is the maximum deviation distance, and its value is μ = max(box). 长 box 宽 box 高 )×0.001, box 长 box 宽 box 高 It is the three-dimensional dimension of the cuboid that perfectly encloses the geometric entity.

[0071] 2.1.2 Constructing the surface midline in the surface parameter space using the discretized representation of a curve. If curve C and surface S have a topological relationship, then the three-dimensional discrete points in the discretized representation of curve C also lie on surface S. The corresponding coordinates of the three-dimensional discrete points of curve C in this parameter space are found through the parametric equations of curve S, thus constructing the surface midline. For example... Figure 4 As shown, the arrow points to the 3D curve of the surface boundary, which constructs the corresponding surface midline in the parameter space. This application greatly optimizes the processing flow for geometric repair and feature simplification of automotive geometric models by establishing a common representation based on continuous geometry, discrete geometry, and topological relationships during the reading stage of the automotive geometric model undergoing CFD analysis.

[0072] Step 108: Based on the common representation, perform missing data repair and accuracy defect repair for automobile styling data according to three types of geometric entities: surface, curve, and geometric point, to obtain the repaired automobile styling geometric model.

[0073] 2.2.1 Repairing missing vehicle styling data, processed separately for three types of geometric entities: surfaces, curves, and geometric points.

[0074] (1) Surface missing topological loop. For example Figure 5 As shown, the specific process includes: establishing four intersecting surface midlines at the surface boundary in the parameter space. With topological edge p' n (u)(n=1,2,3,4) forms a topological ring, and at the same time, the inclusion relationships between the topological ring and the topological surface, and between the topological ring and the topological edge are constructed.

[0075] (2) The topological edge lacks a corresponding curve. The surface midline corresponding to the topological edge is used to reconstruct the NURBS surface. If the surface midline is located at the boundary of the parameter space, the curve parameters of the boundary are extracted according to the NURBS surface equation, and the extracted curve is divided by the parameter coordinate interval of the surface midline; if the surface midline is located inside the parameter space, the discrete points of the surface midline are used as the initial point sequence, and the method described in step 2.1.1 is used to determine whether interpolation is needed to meet the accuracy requirements by the deviation distance between adjacent discrete points. Then, the parameter coordinates of the discrete points are converted into three-dimensional coordinates by the NURBS surface equation, and finally, a first-order NURBS curve is established with the discrete points as control vertices.

[0076] (3) The vertex is missing a corresponding geometric point. The missing geometric point is reconstructed and repaired using the start and end coordinates of the corresponding topological edge discrete representation.

[0077] 2.2.2 Repair of accuracy defects in automotive styling data can be divided into geometric accuracy defects and topological accuracy defects, and is also repaired according to three types of geometric entities: surfaces, curves, and geometric points.

[0078] Detect the surface for precision defects and repair them according to different types:

[0079] (1) Find two adjacent topological surfaces and two topological edges at their intersection lines using topological relationships;

[0080] (2) Calculate the Hausdorff distance between the geometric curves corresponding to the two topological edges, and use the curve coincidence to determine whether there are accuracy defects in the surface. The calculation process for the Hausdorff distance between surfaces and between curves is as follows: calculate the projection distance from a discrete point in the discrete representation of a surface or curve to another surface or curve, and the maximum value of all projection distances in the two surfaces or curves is the Hausdorff distance. The projection distance from a discrete point to a curve or surface is equivalent to calculating the shortest distance from the point to the curve or surface.

[0081] (3) For two surfaces with precision defects, find their intersection. If an intersection line exists, it indicates a topological precision defect. Use the found intersection line as a new topological edge and update the corresponding 3D curve data. If no intersection line exists, it indicates a geometric precision defect. Repair it using surface extension or filling methods, such as... Figure 6 This is a schematic diagram of a surface with precision defects. The surface geometric precision defect repair uses two methods: surface extension or filling. The conditions are as follows: extend the surface by the distance of the maximum mesh element size L, and then find the intersection of the surfaces. If there is an intersection line between the extended surfaces, update the corresponding geometric data of the extended surfaces and the intersection line; if the surfaces still do not intersect, then create a new surface based on the boundary of the two surfaces and fill it for repair.

[0082] Does the detection curve have accuracy defects, such as...? Figure 7 As shown, defects of different precision are judged and processed separately based on the continuity of the centerlines of adjacent surfaces:

[0083] (1) Find the intersection of the midlines of the topologically connected planes. If an actual intersection point exists, and the distance between the intersection point and the common endpoint is greater than the tolerance ε, then take the new intersection point as the endpoint of the plane midline. The tolerance is calculated as ε = max(box). 长 box 宽 box 高 )×10 -9 box 长 box 宽 box 高 It is the three-dimensional dimension of the cuboid that perfectly encloses the geometric entity. If the distance between the intersection point and the common endpoint is less than the tolerance ε, it remains unchanged. If there is no actual intersection point, but there is a common endpoint or actual intersection point with other face midlines, the storage positions of the corresponding face midlines are swapped, and the actually connected face midlines are linked together.

[0084] (2) If the above two conditions are not met, it is a geometric accuracy defect. In this case, the midline of the surface is created at the endpoint of the gap, and the corresponding geometric entity curve is reconstructed using the steps described in 2.2.1(2).

[0085] (3) Detect geometric point accuracy defects. When the distance between the coordinates of the geometric point itself and the start and end points of the curve is greater than the tolerance ε, it is determined to be a geometric point accuracy defect. At this time, the erroneous geometric point should be deleted and the corresponding geometric point should be reconstructed using the steps described in 2.2.1(3).

[0086] Based on common representations, missing data and accuracy defects in automotive styling are repaired for three types of geometric entities: surfaces, curves, and geometric points. The automotive geometric model is automatically repaired to meet the mesh generation requirements, avoiding the time-consuming and laborious manual repair process and greatly improving the repair efficiency of automotive styling geometric models.

[0087] In the aforementioned automatic repair method for automotive styling geometric models, this application establishes a common representation based on continuous geometry, discrete geometry, and topological relationships during the reading stage of the automotive geometric model for CFD analysis. This greatly optimizes the processing flow for geometric repair and feature simplification of the automotive geometric model. Furthermore, addressing the issue that automotive styling cannot be directly used for aerodynamic design analysis, the method repairs missing data and accuracy defects in automotive styling based on the common representation, categorizing the data into three types of geometric entities: surfaces, curves, and geometric points. This automatically repairs the automotive geometric model to meet mesh generation requirements, avoiding the time-consuming and laborious manual repair process and significantly improving the repair efficiency of automotive styling geometric models.

[0088] In one embodiment, the continuous geometry represented by three-dimensional curves and three-dimensional surfaces is discretized to construct a geometric model for joint characterization, including:

[0089] Discretize the continuous geometry, determine the position of the discrete segmentation point of the continuous geometry in the parameter domain, use the node vector defined by NURBS of the three-dimensional curve or three-dimensional surface as the parameter coordinate of the initial discrete point, and then determine whether interpolation is needed to meet the accuracy requirements by the deviation distance between adjacent discrete points, so as to obtain the discrete representation of the curve or surface.

[0090] The midline of a surface is constructed using a discretized curve representation.

[0091] In one embodiment, the process of calculating the deviation distance between discrete points includes:

[0092] The specific method for calculating the deviation distance dev between three consecutive discrete points p1, p2, and p3 is as follows:

[0093]

[0094] In one embodiment, the midline of a surface is constructed using a curve discretization representation, including:

[0095] If curve C and surface S have a topological relationship, then the three-dimensional discrete points in the discrete representation of curve C are also located on surface S. The corresponding coordinates of the three-dimensional discrete points of curve C in the parameter space are found through the parametric equation of curve S to form the midline of the surface.

[0096] In one embodiment, missing data repair for vehicle styling includes topological loop repair of surfaces, curve repair of topological edges, and corresponding geometric point repair of vertices; accuracy defect repair includes geometric accuracy defect repair and topological accuracy defect repair; based on common representations, missing data repair and accuracy defect repair for vehicle styling are performed according to three types of geometric entities: surfaces, curves, and geometric points, including:

[0097] Based on common representations, missing automotive styling data is repaired by classifying them into three types of geometric entities: surfaces, curves, and geometric points. Four intersecting surface midlines and topological edges are established at the surface boundaries in parameter space to form a topological loop, thus completing the topological loop repair of the surface.

[0098] The topological edge is reconstructed using the surface midline corresponding to the surface and the non-degenerate closed smooth surface. If the surface midline is located at the boundary of the parameter space, the curve where the boundary is located is extracted according to the equation of the non-degenerate closed smooth surface, and the extracted curve is segmented by the parameter coordinate interval of the surface midline. If the surface midline is located inside the parameter space, the discrete points of the surface midline are used as the initial point sequence. The deviation distance between adjacent discrete points is used to determine whether interpolation is needed to meet the accuracy requirements. If the accuracy requirements are met, the parameter coordinates of the discrete points are converted into three-dimensional coordinates by the equation of the non-degenerate closed smooth surface. A first-order non-degenerate closed smooth curve is established with the discrete points as control vertices to complete the curve repair of the topological edge.

[0099] The missing geometric points are reconstructed and repaired using the start and end coordinates of the corresponding topological edge discrete representation, resulting in the repaired geometric points.

[0100] In a specific embodiment, extracting the boundary curve based on the equation of a nondegenerate closed smooth surface, and dividing the extracted curve by the parameter coordinate interval of the surface midline, and converting the discrete point parameter coordinates into three-dimensional coordinates by the equation of a nondegenerate closed smooth surface while meeting the accuracy requirements are existing technologies, so they will not be elaborated on in this application.

[0101] In one embodiment, it is determined whether there is a precision defect on the surface. If there is a precision defect on the surface, the precision defect type is detected based on the intersection of the surfaces, and the precision defect is repaired based on the precision defect type.

[0102] Based on the continuity of the centerlines of adjacent surfaces, the curve is inspected for accuracy defects, and the curve accuracy defects are repaired according to the type of accuracy defect.

[0103] In one embodiment, the presence of precision defects on the surface is determined. If precision defects are found, the surface is subjected to precision defect type detection based on its intersecting properties, and precision defect repair is performed based on the precision defect type, including:

[0104] Find two adjacent topological surfaces and two topological edges at their intersection lines based on the topological relationships. Calculate the Hausdorff distance between the geometric curves corresponding to the two topological edges. Determine the curve coincidence based on the Hausdorff distance. Determine whether there are any accuracy defects on the surface based on the curve coincidence.

[0105] If the surface has a precision defect, find the intersection of the two surfaces with the precision defect. If the surfaces have an intersection line, it is a topological precision defect. The obtained intersection line is used as a new topological edge, and the corresponding 3D curve data is updated. If there is no intersection line, it is a geometric precision defect. The surface is repaired by extension or filling.

[0106] In a specific embodiment, the presence of precision defects on the surface is determined based on the curve overlap. First, the tolerance is calculated using the formula ε = max(box). 长 box 宽 box 高 )×10 -9 box 长 box 宽 box 高 It is the three-dimensional dimension of the cuboid that perfectly encloses the geometric entity. If the curve coincidence is less than the tolerance, it is considered to be coincident.

[0107] In one embodiment, the curve is subjected to precision defect detection based on the continuity of the centerlines of adjacent surfaces, and the curve precision defect is repaired according to the type of precision defect, including:

[0108] The intersection of the topologically connected surface midlines is calculated. If an actual intersection point exists and the distance between the intersection point and the common endpoint is greater than the tolerance, the new intersection point is taken as the endpoint of the surface midline. If the distance between the intersection point and the common endpoint is less than the tolerance, it remains unchanged. If no actual intersection point exists, but the topologically connected surface midlines have a common endpoint or an actual intersection point with other surface midlines, the storage locations of the corresponding surface midlines are swapped, and the actual connected surface midlines are connected to achieve topological accuracy defect repair.

[0109] The intersection of the topologically connected surface midlines is calculated. If there is an actual intersection point and the distance between the intersection point and the common endpoint is equal to the tolerance, or if there is no actual intersection point and the topologically connected surface midlines do not have a common endpoint or actual intersection point with other surface midlines, then the curve is repaired with geometric precision. The surface midline is created with the endpoint of the gap, and the geometric solid curve is reconstructed using the surface midline corresponding to the topological edge and the non-degenerate closed smooth surface to achieve the repair of the geometric precision defect of the curve.

[0110] When the distance between the coordinates of a geometric point and the start and end points of the curve is greater than the tolerance, it is determined to be a geometric point precision defect. The erroneous geometric point is deleted, and the missing geometric point is reconstructed and repaired using the start and end coordinates of the corresponding topological edge discrete representation, so as to obtain the repaired geometric point.

[0111] It should be understood that, although Figure 1 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 1At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

[0112] In one embodiment, such as Figure 8 As shown, an automatic repair device for automotive styling geometric models is provided, comprising: an automotive styling geometric model construction module 802, a geometric information acquisition module 804, a discretization module 806, and a defect repair module 808, wherein:

[0113] The automotive styling geometric model module 802 is used to obtain the automotive product sketches constructed during the concept design phase; the automotive product sketches are refined using CAD software to accurately determine the dimensions and positions of each component and construct the automotive styling geometric model.

[0114] The geometric information acquisition module 804 is used to acquire the geometric information of the model from the automotive styling geometric model; the geometric information includes the three-dimensional surfaces, three-dimensional curves, three-dimensional points, and the midlines and points defined on the three-dimensional surfaces in the topological relationship of the geometric model.

[0115] Discretization module 806 is used to discretize the continuous geometry represented by three-dimensional curves and three-dimensional surfaces to construct a common representation of the continuous geometry, discrete geometry, and topological relationships of the geometric model;

[0116] The defect repair module 808 is used to repair missing and precision defects in automotive styling data according to the common characteristics, based on three types of geometric entities: surfaces, curves, and geometric points, to obtain a repaired automotive styling geometric model.

[0117] Specific limitations regarding the automatic repair device for automotive geometric models can be found in the above-described limitations of the automatic repair method for automotive geometric models, and will not be repeated here. Each module in the aforementioned automatic repair device for automotive geometric models can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0118] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 9As shown, the computer device includes a processor, memory, network interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The network interface is used to communicate with external terminals via a network connection. When the computer program is executed by the processor, it implements an automatic repair method for automotive styling geometric models. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the computer device casing, or an external keyboard, touchpad, or mouse.

[0119] Those skilled in the art will understand that Figure 9 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0120] In one embodiment, a computer device is provided, including a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the steps of the method described above.

[0121] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0122] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0123] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for automatically repairing automotive styling geometric models, characterized in that, The method includes: Obtain the automotive product sketches created during the concept design phase; The sketches of the automobile product were refined using CAD software, and the dimensions and positions of each component were precisely determined to construct a geometric model of the automobile. Geometric information of the model is obtained from the automotive styling geometric model; the geometric information includes the three-dimensional surfaces, three-dimensional curves, three-dimensional points, and the midlines and points defined on the three-dimensional surfaces in the topological relationship of the geometric model. Discretize the continuous geometry represented by three-dimensional curves and three-dimensional surfaces to construct a common representation of continuous geometry, discrete geometry, and topological relationships in the geometric model; Based on the common representation, missing data and accuracy defects of automobile styling data are repaired according to three types of geometric entities: surfaces, curves, and geometric points, to obtain the repaired automobile styling geometric model. Discretizing continuous geometry represented by 3D curves and 3D surfaces to construct a common geometric model, including: Discretize the continuous geometry, determine the position of the discrete segmentation point of the continuous geometry in the parameter domain, use the node vector defined by NURBS of the three-dimensional curve or three-dimensional surface as the parameter coordinate of the initial discrete point, and then determine whether interpolation is needed to meet the accuracy requirements by the deviation distance between adjacent discrete points, so as to obtain the discrete representation of the curve or surface. The midline of a surface is constructed using a discretized curve representation.

2. The method according to claim 1, characterized in that, The calculation process for the deviation distance between the discrete points includes: For three continuous discrete points , , Deviation between The specific calculation method is as follows: 。 3. The method according to claim 1, characterized in that, Constructing the surface midline in the surface parameter space using curve discretization includes: If curve C and surface S have a topological relationship, then the three-dimensional discrete points in the discrete representation of curve C are also located on surface S. The corresponding coordinates of the three-dimensional discrete points of curve C in the parameter space are found through the parametric equation of curve S to form the midline of the surface.

4. The method according to claim 2, characterized in that, The missing data repair for the vehicle styling data includes topological loop repair of surfaces, curve repair of topological edges, and repair of corresponding geometric points of vertices; the accuracy defect repair includes geometric accuracy defect repair and topological accuracy defect repair. Based on the common representation, missing data and accuracy defects in automotive styling data are repaired according to three types of geometric entities: surfaces, curves, and geometric points. This includes: Based on the common representation, missing automotive styling data is repaired according to three types of geometric entities: surfaces, curves, and geometric points. Four intersecting surface midlines and topological edges are established at the surface boundary in the parameter space to form a topological loop, thus completing the topological loop repair of the surface. The topological edge is reconstructed using the surface midline corresponding to the surface and the non-degenerate closed smooth surface. If the surface midline is located at the boundary of the parameter space, the curve where the boundary is located is extracted according to the equation of the non-degenerate closed smooth surface, and the extracted curve is segmented by the parameter coordinate interval of the surface midline. If the surface midline is located inside the parameter space, the discrete points of the surface midline are used as the initial point sequence. The deviation distance between adjacent discrete points is used to determine whether interpolation is needed to meet the accuracy requirements. If the accuracy requirements are met, the parameter coordinates of the discrete points are converted into three-dimensional coordinates by the equation of the non-degenerate closed smooth surface. The first-order non-degenerate closed smooth curve is established with the discrete points as control vertices to complete the curve repair of the topological edge. The missing geometric points are reconstructed and repaired using the start and end coordinates of the corresponding topological edge discrete representation, resulting in the repaired geometric points.

5. The method according to claim 4, characterized in that, The method further includes: The surface is assessed for precision defects. If precision defects are found, the surface is tested for precision defect type based on its intersection, and the precision defects are repaired according to the type of precision defect. Based on the continuity of the centerlines of adjacent surfaces, the curve is inspected for accuracy defects, and the curve accuracy defects are repaired according to the type of accuracy defect.

6. The method according to claim 5, characterized in that, The system determines whether the surface has precision defects. If precision defects are found, the surface is then inspected for the type of precision defect based on its intersecting properties. Repair of the precision defects is then performed according to the type of defect, including: Find two adjacent topological surfaces and two topological edges at their intersection lines based on the topological relationship. Calculate the Hausdorff distance between the geometric curves corresponding to the two topological edges. Determine the curve coincidence based on the Hausdorff distance. Determine whether there are accuracy defects on the surface based on the curve coincidence. If the surface has a precision defect, find the intersection of the two surfaces with the precision defect. If the surfaces have an intersection line, it is a topological precision defect. The obtained intersection line is used as a new topological edge, and the corresponding 3D curve data is updated. If there is no intersection line, it is a geometric precision defect. The surface is repaired by extension or filling.

7. The method according to claim 6, characterized in that, Based on the continuity of the centerlines of adjacent surfaces, the curve is inspected for accuracy defects, and the curve accuracy defects are repaired according to their types, including: The intersection of the topologically connected surface midlines is calculated. If an actual intersection point exists and the distance between the intersection point and the common endpoint is greater than the tolerance, the new intersection point is taken as the endpoint of the surface midline. If the distance between the intersection point and the common endpoint is less than the tolerance, it remains unchanged. If no actual intersection point exists, but the topologically connected surface midlines have a common endpoint or an actual intersection point with other surface midlines, the storage locations of the corresponding surface midlines are swapped, and the actual connected surface midlines are connected to achieve topological accuracy defect repair. The intersection of the topologically connected surface midlines is calculated. If there is an actual intersection point and the distance between the intersection point and the common endpoint is equal to the tolerance, or if there is no actual intersection point and the topologically connected surface midlines do not have a common endpoint or actual intersection point with other surface midlines, then the curve is repaired with geometric precision. The surface midline is created with the endpoint of the gap, and the geometric solid curve is reconstructed using the surface midline corresponding to the topological edge and the non-degenerate closed smooth surface to achieve the repair of the geometric precision defect of the curve. When the distance between the coordinates of a geometric point and the start and end points of the curve is greater than the tolerance, it is determined to be a geometric point precision defect. The erroneous geometric point is deleted, and the missing geometric point is reconstructed and repaired using the start and end coordinates of the corresponding topological edge discrete representation, so as to obtain the repaired geometric point.

8. An automatic repair device for automotive geometric models, characterized in that, The device includes: A module for constructing automotive styling geometric models is used to obtain automotive product sketches created during the conceptual design phase. CAD software is then used to refine these sketches, precisely determining the dimensions and positions of each component to construct the automotive styling geometric model. The geometric information acquisition module is used to acquire the geometric information of the model from the automotive styling geometric model; the geometric information includes the three-dimensional surfaces, three-dimensional curves, three-dimensional points, and the midlines and points defined on the three-dimensional surfaces in the topological relationship of the geometric model. The discretization module is used to discretize the continuous geometry represented by 3D curves and 3D surfaces to construct a common representation of the continuous geometry, discrete geometry, and topological relationships of the geometric model; the discretization of the continuous geometry represented by 3D curves and 3D surfaces to construct a common representation of the geometric model includes: Discretize the continuous geometry, determine the position of the discrete segmentation point in the parameter domain, use the node vector defined by NURBS for the 3D curve or 3D surface as the parametric coordinate of the initial discrete point, and then determine whether interpolation is needed to meet the accuracy requirements by the deviation distance between adjacent discrete points, thus obtaining the discrete representation of the curve or surface; use the discrete representation of the curve to construct the surface midline in the surface parameter space; The defect repair module is used to repair missing and precision defects in automotive styling data according to the common characteristics of three types of geometric entities: surfaces, curves, and geometric points, to obtain the repaired automotive styling geometric model.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.

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