Method for intelligently calculating symmetry degree and symmetry plane of casting three-dimensional model

Abstract

The invention discloses a method for intelligently calculating the symmetry degree and the symmetry plane of a casting three-dimensional model. The method comprises the steps that the three-dimensional model of the symmetry degree of a casting to be calculated is obtained, and length, width, height and posture standardization processing is calculated; sectioning the three-dimensional model after attitude standardization processing along any plane where a three-dimensional coordinate axis is located to obtain a first sub-model and a second sub-model; sequentially irradiating the first sub-model and the second sub-model by using a plurality of rays with the same number and opposite directions along a corresponding sectioning plane perpendicular to the selected sub-model; respectively counting the distance of a ray penetrating through each ray of the first sub-model and the second sub-model to obtain a first vector and a second vector and calculating the similarity of the first vector and the second vector, and the calculation result is the symmetry degree of the current sectioning plane; according to the method, any remaining plane where the coordinate axis is located is selected to be sectioned, and the similarity of the vectors corresponding to the sectioned sub-models of each sectioning plane is calculated in sequence; all similarities are compared, and the maximum value is the symmetry degree of the model.

Description

Technical Field

[0001] The invention relates to the technical field of symmetry detection, and in particular to a method for intelligently calculating the symmetry and symmetry plane of a three-dimensional casting model. Background Art

[0002] Casting technology is one of the basic and irreplaceable methods in advanced manufacturing. The design of casting gating system plays a vital role in ensuring the quality of castings. A well-designed gating system can ensure that the molten metal fills the mold cavity smoothly and reasonably, avoid turbulence and scouring of the mold, reduce defects such as pores, inclusions and shrinkage in the casting, and thus improve the yield and quality of the casting.

[0003] The complexity of the casting needs to be considered when designing the gating system. Symmetry is one of the indicators of the complexity of the casting. Symmetry refers to the degree of symmetry of the casting in terms of geometry. Due to the regularity and repeatability brought by symmetry, the gating system and mold design of symmetrical castings are simpler than those of asymmetrical castings. Symmetry also helps to simplify the prediction of cooling and shrinkage because each part of the casting will respond to temperature changes in a similar way. For example, for symmetrical castings, center pouring can be used so that the molten metal is evenly distributed from the center to each part, which is conducive to uniform cooling of the casting and reducing internal stress. For asymmetrical castings, a complex gating system needs to be designed.

[0004] Currently, the symmetry of castings is usually judged manually, which requires accurate structural knowledge of the castings. In addition, the trimesh library provides a method for judging the symmetry of the three-dimensional model of castings, but there will be judgment deviations for complex castings and the symmetry cannot be provided. Summary of the invention

[0005] In order to solve some or all of the technical problems existing in the above-mentioned prior art, the present invention provides a method for intelligently calculating the symmetry and symmetry plane of a three-dimensional model of a casting, which can accurately calculate the symmetry and symmetry plane, avoids the problem of low accuracy of manual judgment, and solves the problem of lack of symmetry calculation method and only symmetry judgment in the prior art. By obtaining the symmetry and symmetry plane of the three-dimensional model of the casting, the symmetry information of the casting is provided to the casting process designer, reducing the manpower consumption in the process design process.

[0006] The technical solution of the present invention is as follows:

[0007] In a first aspect, the present invention provides a method for intelligently calculating the symmetry of a three-dimensional casting model, comprising:

[0008] Obtaining a three-dimensional model of the actual casting symmetry to be calculated, and calculating the length, width and height of the three-dimensional model;

[0009] Performing posture standardization processing on the acquired 3D model so that the geometric center of the acquired 3D model is aligned with the origin of the preset 3D coordinates, and placing the side with the largest length, width and height of the 3D model in the Z-axis direction of the preset 3D coordinates;

[0010] The three-dimensional model after posture normalization is cut along any plane where the three-dimensional coordinate axis is located to obtain a first sub-model and a second sub-model, and a first cutting plane on the first sub-model and a second cutting plane on the second sub-model after cutting;

[0011] The obtained first sub-model and the second sub-model are symmetrically distributed along the cut plane, and the first sub-model and the second sub-model are sequentially irradiated with a plurality of rays of the same number and in opposite directions along the cut plane perpendicular to the selected sub-model, and the height range of the ray origin is controlled to be consistent with the height of the selected three-dimensional model of the casting, and the length range of the ray origin is controlled to be consistent with the length range of the selected three-dimensional model of the casting;

[0012] Counting the distances of each ray passing through the first sub-model and the second sub-model respectively, to obtain a first vector corresponding to the first sub-model and a second vector corresponding to the second sub-model;

[0013] Calculate the similarity between the first vector and the second vector, and use the calculated result as the symmetry of the plane cut along the three-dimensional coordinate axis of the three-dimensional model;

[0014] Select any remaining planes along the three-dimensional coordinate axis of the three-dimensional model for sectioning in sequence, obtain the vectors corresponding to the sectioned sub-models under each sectioning plane in sequence, and calculate the similarity of the vectors corresponding to the sectioned sub-models under each sectioning plane;

[0015] Compare the sizes of all similarities, and the maximum similarity is the symmetry of the casting 3D model.

[0016] Furthermore, in the above method for intelligently calculating the symmetry of a three-dimensional casting model, calculating the similarity between the first vector and the second vector includes using a cosine similarity calculation formula for calculation.

[0017] Furthermore, in the above method for intelligently calculating the symmetry of a three-dimensional casting model, the cosine similarity calculation formula includes:

[0018]

[0019] Where A and B represent two n-dimensional vectors respectively.

[0020] Furthermore, in the above method for intelligently calculating the symmetry of the three-dimensional model of the casting, the distance of each ray passing through the first sub-model and the second sub-model is counted respectively. For the i-th ray among the plurality of rays, the distance that the ray penetrates the model is the length that coincides with the three-dimensional model. Then, the length of the i-th ray that coincides with the model is:

[0021] YDA i =2 i -1 i +4 i -3 i +…+N i -(N-1) i

[0022] In the formula, YDA i is the distance that the i-th ray penetrates the model on the first cutting plane PA, N i is the coordinate of the Nth intersection point between the i-th ray and the model.

[0023] Furthermore, in the above method for intelligently calculating the symmetry of a three-dimensional casting model, the format of the three-dimensional model of the casting whose symmetry is actually to be calculated is obtained in an STL format.

[0024] Furthermore, in the above method for intelligently calculating the symmetry of a three-dimensional casting model, performing posture standardization processing on the acquired three-dimensional model includes translating, flipping or rotating the three-dimensional casting model.

[0025] Furthermore, in the above method for intelligently calculating the symmetry of a three-dimensional model of a casting, the geometric center of the three-dimensional model includes the coordinates of half the length, half the width and half the height of the three-dimensional model.

[0026] In a second aspect, the present invention also provides a method for intelligently calculating the symmetry plane of a three-dimensional model of a casting. The symmetry plane calculated by this method is the section plane corresponding to the symmetry of the three-dimensional model of the casting calculated using the above-mentioned method for intelligently calculating the symmetry of the three-dimensional model of the casting.

[0027] The main advantages of the technical solution of the present invention are as follows:

[0028] The method for intelligently calculating the symmetry and symmetry plane of a three-dimensional model of a casting of the present invention can fully consider the internal and external structures of the model by dividing the casting model, then counting the distance of rays penetrating the model and calculating the similarity between distance vectors. The method is applicable to castings of any shape, is not limited by the complexity of the model, has strong versatility and adaptability, and the implementation of the method is relatively simple, does not require complex hardware support, can appropriately improve the degree of automation of casting process design, reduce manual intervention, and improve the efficiency and consistency of symmetry calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings described herein are used to provide a further understanding of the embodiments of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0030] Figure 1 Schematic diagram of a casting three-dimensional model in a method for intelligently calculating the symmetry of a casting three-dimensional model according to an embodiment of the present invention, (a) represents the obtained casting three-dimensional model, and (b) represents a schematic diagram after the posture of the obtained three-dimensional model is standardized;

[0031] Figure 2 A schematic structural diagram of a section of a three-dimensional casting model after posture standardization in a method for intelligently calculating the symmetry of a three-dimensional casting model provided by an embodiment of the present invention;

[0032] Figure 3 It is a schematic flow chart of a method for intelligently calculating the symmetry of a three-dimensional casting model according to an embodiment of the present invention;

[0033] Figure 4 A three-dimensional model of a fixed support for calculating symmetry using the method for intelligently calculating symmetry of a three-dimensional model of a casting according to an embodiment of the present invention;

[0034] Figure 5 The invention discloses a three-dimensional model of a fuel pump for which symmetry calculation is performed using a method for intelligently calculating symmetry of a three-dimensional model of a casting according to an embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0036] The technical solution provided by the embodiments of the present invention is described in detail below with reference to the accompanying drawings.

[0037] As attached Figure 1-Figure 5 As shown, the embodiment of the present invention provides a method for intelligently calculating the symmetry of a three-dimensional casting model, such as Figure 3 As shown, the method includes:

[0038] The three-dimensional model of the actual casting symmetry to be calculated is obtained, and the length, width and height of the three-dimensional model are calculated; the posture of the obtained three-dimensional model is normalized so that the geometric center of the obtained three-dimensional model is aligned with the preset three-dimensional coordinate origin, and the side with the largest length, width and height of the three-dimensional model is placed in the Z-axis direction of the preset three-dimensional coordinate; the three-dimensional model after the posture normalization is cut along any plane where the three-dimensional coordinate axis is located to obtain the first sub-model and the second sub-model, as well as the first cutting plane on the first sub-model and the second cutting plane on the second sub-model after cutting; the first sub-model and the second sub-model are symmetrically distributed along the cut plane, and the first sub-model and the second sub-model are irradiated in turn with a number of rays of the same number and opposite directions along the cutting plane perpendicular to the selected sub-model. The height range of the ray origin is controlled to be consistent with the height of the selected three-dimensional model of the casting, and the length range of the ray origin is controlled to be consistent with the length range of the selected three-dimensional model of the casting; the distance of each ray passing through the first sub-model and the second sub-model is counted respectively to obtain a first vector corresponding to the first sub-model and a second vector corresponding to the second sub-model; the similarity of the first vector and the second vector is calculated, and the calculated result is used as the symmetry of the plane of the three-dimensional model cut along the three-dimensional coordinate axis; any remaining planes along the three-dimensional coordinate axis of the three-dimensional model are selected in turn for cutting, and the vectors corresponding to the cut sub-models under each cutting plane are obtained in turn, and the similarity of the corresponding vectors of the cut sub-models under each cutting plane is calculated; all similarities are compared, and the maximum similarity is the symmetry of the three-dimensional model of the casting.

[0039] Thus arranged, the method for intelligently calculating the symmetry of a three-dimensional model of a casting of the present invention divides the obtained three-dimensional model of the casting into two sections along the geometric center, and then irradiates the sections with the same number of rays in opposite directions along the section plane formed by the sections, respectively, and calculates the ray distances passing through the two sections, and obtains corresponding vectors through the ray distances; calculates the similarity between the two through the obtained vectors, and obtains the final similarity value by comparing the similarities obtained after the three-dimensional model is sectioned in different directions, and uses the plane where the final similarity value lies as the symmetry and symmetry plane, which can fully consider the internal and external structures of the model, is applicable to castings of any shape, is not limited by the complexity of the model, has strong versatility and adaptability, and the implementation of the method is relatively simple, does not require complex hardware support, and the obtained symmetry and symmetry plane are more accurate, avoiding the problem of low accuracy of human judgment, improving the efficiency and consistency of symmetry calculation, providing casting process designers with symmetry information of castings, and reducing the consumption of manpower in the process design process.

[0040] In some optional implementations of the present invention, the above method of the present invention can also be used to judge the symmetry and symmetry plane of the three-dimensional model, providing a basis for judging the symmetry and symmetry plane of the three-dimensional model, so as to improve the degree of automation of casting process design, reduce manual intervention, and improve the efficiency and consistency of symmetry calculation.

[0041] Specifically, in the method for intelligently calculating the symmetry of a three-dimensional casting model of the present invention, calculating the similarity between the first vector and the second vector includes using a cosine similarity calculation formula for calculation; the cosine similarity calculation formula includes:

[0042]

[0043] Where A and B represent two n-dimensional vectors respectively.

[0044] In the method for intelligently calculating the symmetry of a three-dimensional model of a casting of the present invention, the casting model is segmented, and then the distance of the ray penetrating the model is counted and the similarity between the distance vectors is calculated. The principle is: if the casting is symmetrical, the two sub-models obtained by segmenting along the symmetry plane are consistent, and the distance that the same ray passes through each sub-model is equal.

[0045] Exemplarily, according to the above principle, based on the three-dimensional model of the casting after posture standardization, taking the three-dimensional Cartesian coordinates (X, Y, Z) as an example, the three-dimensional model of the casting is divided along a plane parallel to the YZ plane, and the dividing plane is perpendicular to the X-axis and is located at half the length of the X-axis dimension of the three-dimensional model.

[0046] Two sub-models A and B are obtained by segmentation, and a plane P is formed on the section surface of the two sub-models A and B. A and P B , at this time along a plane P parallel to the splitting surface A 500 rays are emitted, and the ray emission surface P A Located on one side of the boundary of the sub-model and parallel to the subdivision plane, the length and width of the plane should just cover the sub-model A, and the direction of the ray is the same as that of the plane P. A Vertical and toward the model, the initial position of the ray is on plane P A The plane is divided into equal distances according to its length and width, and the 500 rays are recorded by position, and the emission position of each ray is recorded as [AX1, AY1, AZ1], [AX2, AY2, AZ2]...[AX 499 ,AY 499 , A.Z. 499 ],[AX 500 ,AY 500 , A.Z. 500]; if the ray passes through the model, the distance of the ray penetrating the model is calculated, and the distance of each ray penetrating the model is counted to obtain a vector D with a dimension of 500 A .

[0047] For sub-model B, the ray emission surface P B Should be with plane P A Symmetrical along the model division plane, the ray emission direction is parallel to plane P A The emitted rays are in opposite directions, and the emission point of each ray is at the same position as the plane P. A The ray emission point is mirror-symmetrical about the splitting surface, that is, A The X-axis coordinates of the emission position coordinates of each point of the ray emission point are reversed, then P B The coordinates of the ray emission points on the plane are [-AX1, AY1, AZ1], [-AX2, AY2, AZ2]...[-AX 499 ,AY 499 , A.Z. 499 ], [-AX 500 ,AY 500 , A.Z. 500 ]. Statistics P B Each ray emitted by the plane passes through the model, and a vector D with a dimension of 500 is obtained. B The symmetry calculated above is taken as the symmetry of the model along the YZ plane and is denoted as SymY-Z.

[0048] The same method is used to calculate the symmetry SymX-Z of the casting model along the XZ plane and the symmetry SymX-Y of the XY plane. Then the maximum value among SymY-Z, SymX-Z and SymX-Y is taken as the symmetry of the casting model, and the symmetry plane is determined according to the maximum value.

[0049] In this way, the symmetry and symmetry plane of the casting three-dimensional model can be obtained.

[0050] Specifically, in the method for intelligently calculating the symmetry of a three-dimensional casting model of the present invention, the distance of each ray passing through the first sub-model and the second sub-model is counted respectively. For the i-th ray among the plurality of rays, the distance that the ray penetrates the model is the length that coincides with the three-dimensional model. Then, the length of the i-th ray that coincides with the model is:

[0051] YDA i =2 i -1 i +4 i -3 i +…+N i -(N-1) i

[0052] In the formula, YDA i is the distance that the i-th ray penetrates the model on the first cutting plane PA, N i is the coordinate of the Nth intersection point between the i-th ray and the model.

[0053] In the method for intelligently calculating the symmetry of a three-dimensional casting model of the present invention, the format of the three-dimensional model of the actual casting symmetry to be calculated is preferably obtained in STL format.

[0054] In some optional implementations, the format of the three-dimensional model can also adopt stp or step, x_t or iges and other formats. The STL format in the present invention is only an exemplary description and practical application format, not the only limitation on the three-dimensional model format. The specific format requirements depend on the needs.

[0055] In the method for intelligently calculating the symmetry of a casting three-dimensional model of the present invention, the posture standardization processing of the acquired three-dimensional model includes translating, flipping or rotating the casting three-dimensional model. The purpose is to place the preset three-dimensional coordinate origin at the geometric center of the model. The model is rotated, and the side with the largest length, width and height values ​​of the model is placed on the Z axis. The model before and after standardization is as follows: Figure 1 As shown, Figure 1 (a) is rotated and translated to obtain (b).

[0056] In some optional implementations of the present embodiment, for example, the casting whose symmetry is to be calculated is input into the corresponding calculation software, the software for calculating the symmetry reads the input three-dimensional model of the casting, automatically makes the geometric center of the input three-dimensional model of the casting coincide with the origin of the three-dimensional coordinates already in the software, and rotates the side with the largest length, width, and height values ​​of the three-dimensional model to be aligned with the Z-axis direction of the existing three-dimensional coordinates before performing the calculation.

[0057] Specifically, in the method for intelligently calculating the symmetry of a casting three-dimensional model of the present invention, the geometric center of the three-dimensional model includes the coordinates of half the length, half the width and half the height of the three-dimensional model.

[0058] With such a setting, the geometric center of the three-dimensional model of the casting is found by adopting the dichotomy method, which is simple to operate and accurate in structure.

[0059] On the other hand, the present invention also provides a method for intelligently calculating the symmetry plane of a three-dimensional model of a casting, wherein the calculated symmetry plane is a section plane corresponding to the symmetry of the three-dimensional model of the casting calculated by the method for intelligently calculating the symmetry of the three-dimensional model of the casting.

[0060] Exemplarily, the above method is used to measure the symmetry of the wheel to obtain the final symmetry and symmetry plane of the wheel, specifically:

[0061] Get the three-dimensional model of the wheel casting in STL file format, calculate the length L, width W, and height H of the three-dimensional model of the wheel casting, and perform posture standardization of the three-dimensional model. Place the origin of the coordinate system at the geometric center of the model, and the coordinates of the geometric center of the model are (L / 2, W / 2, H / 2). Rotate the model and place the side with the largest length, width, and height values ​​of the model on the Z axis. The model before and after standardization is as follows: Figure 1 shown.

[0062] On the basis of the model with standardized posture, the symmetry calculation is performed according to the following principle: if the casting is symmetrical, the two sub-models obtained by sectioning along the symmetry plane are consistent, and the same ray passes through each sub-model at the same distance.

[0063] The model is divided along the YZ plane, XZ plane, and XY plane, and two sub-models are obtained each time. Figure 2 As shown, the present invention is described by dividing the XZ plane and calculating the symmetry of the XZ plane. The calculation method of the symmetry of the YZ plane and the XY plane is consistent with the calculation method of the symmetry of the XZ plane.

[0064] The standardized casting 3D model is split along the XZ plane, and the splitting plane is located at half the length of the Y axis, such as Figure 2 As shown, half the length L.

[0065] After the model is split, two sub-models A and B are obtained. At this time, two planes P are established. A (i.e. the first cutting plane) and P B (i.e. the second cutting plane), plane P A and P B The plane P is symmetrical about the XZ plane and parallel to the XZ plane. A and P B They are located on one side of sub-models A and B respectively, but do not overlap with the sub-models. At the same time, in order to ensure that the subsequent rays can have a stable intersection with the model, the plane P A and P B The size of the two planes needs to be limited. The length of the two planes is W (the width of the casting) and the width is H (the height of the casting). Figure 2 shown.

[0066] In plane P A The length of the plane is divided equally according to the length and width, so that 500 points are evenly selected as the origin of the ray, and the direction of the ray is the positive direction of the Y axis. Similarly, these 500 points are taken as symmetrical points, and the symmetry plane is the XZ plane, so that in plane P B 500 ray origins were also obtained on the plane P B The direction of the ray emitted from the plane is the negative direction of the Y axis, so the plane PA and P B The emitted rays are only opposite in direction. If the model is symmetrical along the XZ plane, then plane P A and P B The length of each ray emitted that coincides with the model should be equal.

[0067] For plane P A The distance between each emitted ray and the model is counted. For the i-th ray, the distance that the ray penetrates the model is the length that overlaps with the model. If the ray has an intersection with the model, the number of intersections is an even number because the ray needs to penetrate the model. Then the length of the overlap between the i-th ray and the model is

[0068] YDA i =2 i -1 i +4 i -3 i +…+N i -(N-1) i

[0069] In the formula, YDA i For plane P A The distance that the i-th ray penetrates the model, N i is the coordinate of the Nth intersection point between the i-th ray and the model. A The distance length of the 500 rays penetrating the sub-model A is obtained to obtain a vector YDA with a dimension of 500. Similarly, the plane P can be obtained in turn. B The above 500 rays penetrate the sub-model B to obtain a vector YDB with a dimension of 500.

[0070] The similarity between vectors YDA and YDB, SymX-Z, is calculated based on cosine similarity and is used as the symmetry of the casting about the XZ plane. Similarly, the symmetry of the casting model about the YZ plane and the XY plane, SymY-Z and SymX-Y, are obtained.

[0071] The maximum value of SymX-Z, SymY-Z and SymX-Y is taken as the symmetry of the casting three-dimensional model, and the symmetry plane can be obtained according to the maximum value. In this embodiment, the symmetry of the hub is 1, and the symmetry plane is the XZ plane.

[0072] The trimesh library is used for calculation, and the returned result is radial, which means it has axial symmetry.

[0073] In addition, it should be noted that the more rays there are, the more precise and accurate the detected results will be, but the more rays there are, the longer the calculation time will be, the more difficult the calculation will be, and the overall time will be longer. Therefore, the number of rays is determined according to the size of the casting. The preferred number of rays is between 300 and 800, and the most preferred number of rays is between 400 and 600.

[0074] For example, in order to verify the accuracy of the method for intelligently calculating the symmetry and symmetry plane of the casting three-dimensional model of the present invention, the symmetry and symmetry plane of the fixed support and the fuel pump are calculated. Specifically, the casting three-dimensional model of the fixed support is as follows: Figure 4 As shown in the figure, the three-dimensional model of the fuel pump casting is as follows Figure 5 The calculation results of the present invention are as follows: the symmetry of the fixed support is 1, which is symmetrical about the XZ plane; the symmetry of the fuel pump is 0.7292, which has the highest symmetry about the XZ plane. The calculation results returned by the trimesh library are as follows: the calculation result of the fixed support is None, which means it has no symmetry; the calculation result of the fuel pump is None, which means it has no symmetry.

[0075] It can be seen that by using the method of the present invention to detect the symmetry of the model of the actual casting, the process design direction can be determined according to the symmetry detection result, and then the casting is cast. The method of the present invention can fully consider the internal and external structures of the model, can provide a reference for the symmetry of the actual product, and can fully consider the internal and external structures of the model, is applicable to castings of any shape, and is not limited by the complexity of the model. It has strong versatility and adaptability, can improve the automation of casting process design, solve the current lack of symmetry calculation method, only symmetry judgment problem, to obtain the symmetry and symmetry plane of the three-dimensional model of the casting to provide the casting process designer with symmetry information of the casting, and reduce the consumption of manpower in the process design process.

[0076] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In addition, "front", "back", "left", "right", "upper" and "lower" in this article are all referenced to the placement state shown in the accompanying drawings.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for intelligently calculating the symmetry of a three-dimensional casting model, characterized in that: include: Obtaining a three-dimensional model of the actual casting symmetry to be calculated, and calculating the length, width and height of the three-dimensional model; Performing posture standardization processing on the acquired 3D model so that the geometric center of the acquired 3D model is aligned with the origin of the preset 3D coordinates, and placing the side with the largest length, width and height of the 3D model in the Z-axis direction of the preset 3D coordinates; The three-dimensional model after posture normalization is cut along any plane where the three-dimensional coordinate axis is located to obtain a first sub-model and a second sub-model, and a first cutting plane on the first sub-model and a second cutting plane on the second sub-model after cutting; The obtained first sub-model and the second sub-model are symmetrically distributed along the cut plane, and the first sub-model and the second sub-model are sequentially irradiated with a plurality of rays of the same number and in opposite directions along the cut plane perpendicular to the selected sub-model, and the height range of the ray origin is controlled to be consistent with the height of the selected three-dimensional model of the casting, and the length range of the ray origin is controlled to be consistent with the length range of the selected three-dimensional model of the casting; Counting the distances of each ray passing through the first sub-model and the second sub-model respectively, to obtain a first vector corresponding to the first sub-model and a second vector corresponding to the second sub-model; Calculate the similarity between the first vector and the second vector, and use the calculated result as the symmetry of the plane cut along the three-dimensional coordinate axis of the three-dimensional model; Select any remaining planes along the three-dimensional coordinate axis of the three-dimensional model for sectioning in sequence, obtain the vectors corresponding to the sectioned sub-models under each sectioning plane in sequence, and calculate the similarity of the vectors corresponding to the sectioned sub-models under each sectioning plane; Compare the sizes of all similarities, and the maximum similarity is the symmetry of the casting 3D model.

2. The method for intelligently calculating the symmetry of a three-dimensional casting model according to claim 1, characterized in that: Calculating the similarity between the first vector and the second vector includes using a cosine similarity calculation formula for calculation.

3. The method for intelligently calculating the symmetry of a three-dimensional casting model according to claim 2, characterized in that: The cosine similarity calculation formula includes: Where A and B represent two n-dimensional vectors respectively.

4. The method for intelligently calculating the symmetry of a three-dimensional casting model according to claim 1, characterized in that: The distance of each ray passing through the first sub-model and the second sub-model is counted respectively. For the i-th ray among several rays, the distance that the ray penetrates the model is the length that coincides with the three-dimensional model. Then the length of the i-th ray that coincides with the model is: YES i =2 i -1 i +4 i -3 i +…+N i -(N-1) i In the formula, YDA i The first cutting plane P A The distance that the i-th ray penetrates the model, N i is the coordinate of the Nth intersection point between the i-th ray and the model.

5. The method for intelligently calculating the symmetry of a three-dimensional casting model according to claim 1, characterized in that: The formats for obtaining the three-dimensional model of the actual casting symmetry to be calculated include STL formats.

6. The method for intelligently calculating the symmetry of a three-dimensional casting model according to claim 1, characterized in that: The posture standardization processing of the acquired three-dimensional model includes translating, flipping or rotating the three-dimensional model of the casting.

7. The method for intelligently calculating the symmetry of a three-dimensional casting model according to claim 1, characterized in that: The geometric center of the three-dimensional model includes the coordinates of half the length of the three-dimensional model, half the width of the three-dimensional model, and half the height of the three-dimensional model.

8. A method for intelligently calculating the symmetry surface of a three-dimensional casting model, characterized in that: The calculated symmetry plane is a section plane corresponding to the symmetry of the three-dimensional model of the casting calculated by applying the method for intelligently calculating the symmetry of the three-dimensional model of the casting described in any one of claims 1 to 7.

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