Multi-entity mesh partitioning method, electronic device, and storage medium

Abstract

The application discloses a multi-entity meshing method, an electronic device and a storage medium, and is used for converting a target entity of a geometric space into a hexahedron-based mesh of a parameter space. The application divides the target entity into a plurality of simple-shaped sub-entities, performs multi-entity collaborative division, uses geometric feature matching and topological relationship analysis, automatically identifies and extracts contact surfaces between the multi-entities, and automatically defines a sweepable parameter, so that a target surface is extracted without manually selecting entities to perform Boolean operation or is swept one by one. The common node algorithm is adopted, common node constraints are applied in the meshing stage, common node meshes are generated, and error accumulation in traditional division and merging is avoided.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of automatic simulation modeling, and particularly relates to a multi-entity meshing method, an electronic device and a storage medium. BACKGROUND

[0002] In the field of automatic simulation, hexahedral mesh is the first choice for complex problem simulation due to its high cell quality, good calculation accuracy and fast convergence speed. Compared with tetrahedral mesh, hexahedral mesh can provide more accurate stress distribution, lower numerical dissipation and significantly reduce solving time under the same calculation scale. When simulating these problem scenarios, not only the mesh quality of a single entity is required, but also the contact surface mesh of different entities needs to be co-nodal, that is, the adjacent meshes are strictly aligned at the junction, otherwise it will lead to calculation error or even solving failure.

[0003] Currently, the meshing methods of hexahedron include sweep method, mapping method, decomposition-based method, etc., but there are still problems such as low automation and low calculation efficiency in the multi-entity co-nodal mesh generation. SUMMARY

[0004] In order to solve the above problems, the present application provides a multi-entity meshing method, an electronic device and a storage medium.

[0005] The method of the present application includes: a multi-entity meshing method for converting a target entity of a geometric space into a hexahedral-based mesh in a parameter space, comprising:

[0006] The target entity information of the geometric space is acquired, the target entity is divided into a plurality of simple shape sub-entities in contact, each of which can be expressed by a general shape; according to the geometric space information of each sub-entity, the sub-entities in contact are extracted, and a side surface of the sub-entity in contact with other sub-entities is defined as a contact surface, and two contact surfaces belonging to two sub-entities but in contact are defined as a contact surface group; according to the area of the contact surface of each sub-entity, a contact surface is selected as a main contact surface, and other contact surfaces are selected as auxiliary contact surfaces, and an information structure body is constructed according to the main contact surface and the auxiliary contact surface; according to the spatial geometric information of each sub-entity and the information structure body data, a sweeping parameter and an approximate global seed are acquired; according to the sweeping parameter and the approximate global seed, a sweeping surface sub-grid of each sub-entity is established in a parameter space, the sub-grid is a quadrilateral grid, and each sub-entity corresponds to a sub-grid; according to the mapping relationship between each contact surface group and each sub-grid, a sub-grid in contact and a contact area corresponding to each contact surface group on the sub-grid are acquired, and a contact unit cell of each sub-grid and a boundary unit cell around the outside of the contact unit cell are acquired according to the contact area; if the node positions of the contact unit cells of two sub-grids in contact are inconsistent, the contact unit cell of one sub-grid is deleted, the nodes adjacent to the deleted contact unit cell in the contact unit cell of the other sub-grid are connected with the nodes adjacent to the side of the boundary unit cell of the deleted one sub-grid to form a transition unit cell with common nodes; according to the transition unit cell and each sub-grid, a global grid of the target entity is generated, and a hexahedron-based grid of the target entity is acquired according to the global grid and the approximate global seed.

[0007] On the basis of the above method, further, the screening method of the main contact surface and the auxiliary contact surface includes taking the contact surface with the largest area as the main contact surface and taking the remaining contact surfaces as the auxiliary contact surfaces.

[0008] On the basis of the above method, further, the information structure body storage information includes main contact surface information, auxiliary contact surface information, entity information to which each contact surface belongs, and normal vector information of each contact surface pointing to the inside of the entity.

[0009] On the basis of the above method, further, in the process of deleting the contact unit cell of one sub-grid and connecting the nodes adjacent to the deleted contact unit cell in the contact unit cell of the other sub-grid with the nodes adjacent to the side of the boundary unit cell of the deleted one sub-grid to form a transition unit cell with common nodes, the contact unit cell of the sub-entity mapping sub-grid with the larger contact surface is taken as the deleted one.

[0010] On the basis of the above method, further, in the process of connecting the nodes adjacent to the deleted contact cells of the other party sub-grid with the nodes adjacent to the boundary cells of the deleted party sub-grid to form the transition cells with common nodes, the nodes adjacent to the boundary cells are actively connected with the nodes adjacent to the contact cells of the other party sub-grid.

[0011] On the basis of the above method, further, the process of actively connecting the nodes adjacent to the boundary cells with the nodes adjacent to the contact cells of the other party sub-grid includes: matching and connecting the nodes adjacent to the boundary cells with the nodes adjacent to the contact cells by the nearest neighbor method to form initial transition cells, and deleting the repeated lines of the initial transition cells according to the principle that each node of the boundary cells can only be connected with one node of the contact cells, so as to obtain the transition cells.

[0012] The application further provides an electronic device including a memory and a processor, the memory storing a computer program, and the processor being configured to execute the method in any of the above technical solutions by the computer program.

[0013] The application further provides a computer readable storage medium including a stored program, wherein the program is executed by a processor to perform the method in any of the above technical solutions.

[0014] The application divides the target entity into a plurality of simple shape sub-entities, automatically identifies and extracts the contact surface between the multiple entities by the multi-entity collaborative division, utilizes the geometric feature matching and the topological relationship analysis, and automatically defines the sweepable parameters without manually selecting the entities to perform the Boolean operation to extract the target surface or sweep one by one. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a flowchart of the method provided by an embodiment of the application;

[0016] Figure 2 is a schematic diagram of a sub-grid in an embodiment of the application;

[0017] Figure 3 is a schematic diagram of two non-common node sub-grids in contact in an embodiment of the application;

[0018] Figure 4 is Figure 3 is a schematic diagram of the contact grid of a sub-grid after deletion in an embodiment of the application;

[0019] Figure 5Fig. 2 is a schematic diagram of a global grid of co-nodes in another embodiment of the present application;

[0020] Figure 6 Fig. 2 is a schematic diagram of a global grid of co-nodes in another embodiment of the present application;

[0021] Figure 7 Fig. 2 is a schematic diagram of a global grid of co-nodes in another embodiment of the present application; DETAILED DESCRIPTION

[0022] The technical solutions of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0023] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0024] In the description of the application, it is necessary to point out that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through intermediate medium, can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances. In the following description, specific details such as specific system structures, techniques are presented in order to thoroughly understand the embodiments of the present application, but it is clear to those skilled in the art that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed description of well-known systems, devices, circuits and methods is omitted to avoid unnecessary details to hinder the description of the present application. It should be understood that when used in the specification and the appended claims, the term "comprising" indicates the presence of the described features, whole, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, whole, steps, operations, elements, components and / or sets. It should also be understood that the term "and / or" used in the specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0025] In the description of the application, it is necessary to point out that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through intermediate medium, can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances. In the following description, specific details such as specific system structures, techniques are presented in order to thoroughly understand the embodiments of the present application, but it is clear to those skilled in the art that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed description of well-known systems, devices, circuits and methods is omitted to avoid unnecessary details to hinder the description of the present application. It should be understood that when used in the specification and the appended claims, the term "comprising" indicates the presence of the described features, whole, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, whole, steps, operations, elements, components and / or sets. It should also be understood that the term "and / or" used in the specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0026] The application will be further described below in conjunction with the drawings.

[0027] Reference Figure 1, the implementation process of the method of the present application. The present application relates to the field of automation simulation (such as finite element analysis, computational fluid dynamics, etc.), and in particular to how to perform hexahedral mesh partitioning and generation in the conversion of entities into hexahedral meshes in simulation software, which can help simulation engineers to efficiently and quickly partition high-quality common-node meshes dominated by hexahedrons. In the present embodiment, the technology used in the mesh partitioning process includes Open CASCADE Technology (OCCT for short), which is a 3D model-related software that can be used for 3D surface and solid modeling, CAD data exchange, and visualization, and can be used to develop computer-aided design, computer-aided manufacturing / measuring, or numerical simulation. In the present embodiment, a mesh partitioning method for multiple entities is used to convert target entities in a geometric space into hexahedral meshes in a parameter space, which includes: obtaining target entity information in a geometric space, partitioning the target entity into multiple simple shape sub-entities that are in contact, each sub-entity can be expressed by a general shape, which is usually a simple cube; according to the geometric space information of each sub-entity, extracting sub-entities that are in contact and defining the side surface of the sub-entity in contact with other sub-entities as a contact surface, and defining two contact surfaces that belong to two sub-entities but are in contact as a contact surface group; according to the area of the contact surface of each sub-entity, selecting a contact surface as a main contact surface and other contact surfaces as auxiliary contact surfaces, and constructing an information structure according to the main contact surface and the auxiliary contact surface. In the present embodiment, the contact surface pairs need to be extracted first, and the large contact surface is defined as the main contact surface and the small contact surface is defined as the auxiliary contact surface according to the size of the contact surface, and the contact surface information structure is established to store the information of each pair of contact surfaces and the mapping relationship with the corresponding entities. According to the spatial geometric information of each sub-entity and the information structure data, the sweeping parameters and the approximate global seed are obtained; according to the sweeping parameters and the approximate global seed, the sweeping surface sub-meshes of each sub-entity are established in the parameter space, and the sub-meshes are quadrilateral meshes, each sub-entity corresponds to a sub-mesh. The sweeping parameters include the sweeping source surface, the target surface, and the path, and the above parameters are obtained according to the contact surface extracted in the previous step and the mapping relationship with the sub-entities, which provides the source surface and the corresponding sub-entities for sweeping. This step mainly uses OCCT to judge the consistency of the entity sampling cross section, so as to judge whether the entity can be swept. If it can be swept, the center of mass of the sampling cross section is extracted, and a B-spline curve is constructed as the sweeping path through the center of mass. According to the sweeping parameters and the approximate global seed, the sweeping surface sub-meshes of each sub-entity are established in the parameter space, and the contact surface is mapped from the geometric space to the parameter space by referring to Figure 2 In the present application, one embodiment of a sub-mesh, the sub-mesh is a quadrilateral mesh, each sub-entity corresponds to a sub-mesh. This step mainly generates a quadrilateral mesh of the sweeping surface, maps the contact surface from the geometric space to the parameter space, generates a plurality of grid nodes with approximate spacing through an approximate global seed, and then associates the grid nodes to form a quadrilateral mesh, as shown inFigures 2-3 The nodes of the grid are shown as circles for the purpose of assisting in the description of the present application. In this step, with reference to Figure 3 , after the two sub-entity contact surfaces are in contact and each generates its own quadrilateral grid, further processing is needed to ensure that the two contact surfaces share nodes. As shown in Figure 3 , the two sub-grids are non-shared-node grids. To this end, the present application obtains the sub-grids in contact and the contact areas of each contact surface group on the sub-grids according to the mapping relationship between each contact surface group and each sub-grid, and obtains the contact cells of each sub-grid and the boundary cells around the outside of the contact cells according to the contact areas; with reference to Figure 4 , if the node positions of the contact cells of the two sub-grids in contact are inconsistent, the contact cells of one sub-grid are deleted, and the nodes adjacent to the deleted contact cells of the other sub-grid are connected to the nodes adjacent to the side nodes of the boundary cells of the deleted sub-grid to form shared-node transition cells, as shown in Figure 5 . The above steps mainly remove all contact areas (i.e., contact cells, the set of all contact grid cells in the sub-grid) in contact with the contact surface of another sub-entity from the contact surface of one sub-entity. Thus, there will be a gap (with reference to Figure 4 in the non-shared-node case, between the boundary cells remaining after the contact cells of one sub-grid are cut out and the contact cells of the other sub-grid) in the contact surface of one sub-entity, and the gap is filled by merging the grid with the gap with the other sub-grid to obtain a large grid composed of two sub-grids to be filled with the gap, and then with reference to Figure 5 , transition cells are generated to complete the filling of the gap between the two sub-grids, and a large grid is obtained after the two sub-grids are connected together, and the two sub-grids are connected by transition cells to achieve shared-node connection. On this basis, all sub-grids are connected by corresponding transition cells to obtain the global grid of the target entity, and a hexahedral grid is obtained based on the global grid and the approximate global seed; in this step, as shown in Figure 6 , with the global grid and the approximate global seed, the step length of the sweep path can be obtained in cooperation with the sweep path, and in combination with the shared-node quadrilateral global grid obtained in the previous step, a hexahedral grid of the target entity can be generated along the sweep path. The present application directly embeds the shared-node algorithm in the grid generation stage, uses hole repair + annular gap filling technology, and makes the node matching accuracy of adjacent entity contact surfaces reach 100%. Compared with the traditional post-processing method (such as the node merging function in ANSYS Workbench), the present application avoids the error accumulation caused by multiple iterations.

[0028] On the basis of the above embodiment, the application is further improved, and the screening mode of the main contact surface and the auxiliary contact surface comprises: taking the contact surface with the largest area as the main contact surface, and taking the remaining contact surfaces as the auxiliary contact surfaces. In the embodiment, the contact surface with the largest area is taken as the main contact surface, and the remaining contact surfaces are taken as the auxiliary contact surfaces, so that the information structure body is conveniently constructed, and the operation efficiency is improved.

[0029] On the basis of one or more of the above embodiments, the application is further improved, and the information stored in the information structure body comprises: main contact surface information, auxiliary contact surface information, entity information to which each contact surface belongs, and normal vector information of each contact surface pointing to the inside of the entity. In the embodiment, the determination of the sweeping source surface, the target surface and the path in the sweeping process of the application can be effectively improved through the above information.

[0030] On the basis of one or more of the above embodiments, the application is further improved, and in the process of connecting the nodes adjacent to the deleted contact cells in the contact cells of the other sub-grid with the nodes adjacent to the boundary cells of the deleted sub-grid to form the transition cells with common nodes, the sub-entity with the larger contact surface is taken as the deleted side. In the application, the sub-grid mapped by the sub-entity with the larger contact surface is taken as the deleted side, so that the contact cells and the boundary cells can be located in the same plane as much as possible, and the generation efficiency of the transition cell ring is improved.

[0031] On the basis of one or more of the above embodiments, the application is further improved, and in the process of connecting the nodes adjacent to the deleted contact cells in the contact cells of the other sub-grid with the nodes adjacent to the boundary cells of the deleted sub-grid to form the transition cells with common nodes, the sub-entity with the larger contact surface is taken as the deleted side. In the application, the sub-grid mapped by the sub-entity with the larger contact surface is taken as the deleted side, so that the contact cells and the boundary cells can be located in the same plane as much as possible, and the generation efficiency of the transition cell ring is improved. Figure 7 In the process of connecting the nodes adjacent to the deleted contact cells in the contact cells of the other sub-grid with the nodes adjacent to the boundary cells of the deleted sub-grid to form the transition cells with common nodes, the nodes adjacent to the boundary cells are actively connected with the nodes adjacent to the contact cells of the other sub-grid.

[0032] On the basis of one or more of the above embodiments, the application is further improved, and in the process of actively connecting the nodes adjacent to the boundary cells with the nodes adjacent to the contact cells of the other sub-grid, the nodes adjacent to the boundary cells are matched and connected with the nodes adjacent to the contact cells by the nearest neighbor method to form initial transition cells, and the repeated lines of the initial transition cells are deleted according to the principle that each node of each boundary cell can only be connected with one node of the contact cell, so as to obtain the transition cells. In the embodiment, while ensuring the connection of the nodes of the two sub-grids, the proportion of the number of hexahedral grids is improved, and only a small number of wedge cells or tetrahedral cells exist in the grid in the transition cell area.

[0033] The application further discloses an electronic device comprising a memory and a processor, the memory storing a computer program, and the processor being configured to execute the steps of any one of the method embodiments described above by using the computer program.

[0034] The application further discloses a computer-readable storage medium comprising a stored program, wherein the program is executed by a processor to perform the steps of any one of the method embodiments described above.

[0035] The application is further described below in the manner of computer program execution.

[0036] The hexahedron-oriented fast meshing method for a target entity is described in the field of computational geometry and CAE (Computer Aided Engineering) simulation preprocessing technology. The embodiment takes a plurality of mutually contacting cubes as an example to describe the implementation process of the technical solution. In the process, feature extraction and geometry processing are realized by OCCT, each sub-entity is represented by a TopoDS_Shape, mesh data is constructed by using VTK 9.3 (Visualization Toolkit three-dimensional computer graphics software), and the core algorithm is written by using C++ 11 standard.

[0037] In the embodiment, the bounding box of each sub-entity TopoDS_Shape is extracted by OCCT, it is firstly judged whether the bounding boxes intersect, if the bounding boxes intersect, all faces TopoDS_Face of the two TopoDS_Shares are traversed, it is calculated whether the normal vectors are parallel, if the normal vectors are parallel, the minimum distance between the two faces is calculated, if the distance is less than 1e -6 , it is determined that the two faces contact, the sub-entity corresponding to the face is recorded, the area of the contact face is obtained, the face with a large area is defined as a main contact face, and the face with a small area is defined as an auxiliary contact face, the information structure body of the face is constructed to store the contact face information, the main contact face and a series of auxiliary contact faces, and the sub-entity to which each contact face belongs are stored, and the normal vector of the contact face pointing to the inside of the corresponding sub-entity is stored. According to the outer bounding box of the sub-entity and the normal vector of the contact face, and the approximate global size of the defined mesh unit, a sampling interval is obtained. The sampling cross section of the entity is obtained along the surface normal of the sub-entity, the centroid of each cross section is calculated, the bounding box and the area of the cross section are calculated, if the area and the length and width of the bounding box of each cross section are all within 1e -6If the sub-entity is inside the swept volume, the sub-entity is determined to be a swept volume. If the sub-entity is a swept volume, the original contact surface is set as the sweep source surface, the last section is set as the target surface, the center of each section is fitted as a B-spline curve, and the B-spline curve is set as the sweep path. The contact surface TopoDS_Face is mapped to the coordinate system parameter domain, and according to the set approximate global seed size, uniform grid nodes are generated in the order from top to bottom and from right to left, then tetrahedral cell data is constructed according to the unit structure, and finally a quadrilateral grid of each sub-entity swept surface is generated. According to the contact condition of each sub-entity, the boundary of all auxiliary contact surfaces in the contact surface pair is obtained to obtain the boundary cell ring, and the near-end cell ring is extracted. If the node positions of the boundary cell rings of the two sub-grid boundaries in contact are inconsistent, the boundary cell ring of one sub-grid is deleted, the node adjacent to the boundary cell ring of the other sub-grid is connected to the node adjacent to the near-end cell ring of the deleted one sub-grid to form a transition cell ring with common nodes. After the sub-grids are connected into a large grid through the transition cell ring, the node distribution is optimized through Laplace smoothing, and finally the final global grid is obtained, as shown in Figure 2 After the global grid is generated, if the grid cell is a triangular grid (only exists on the transition cell ring, refer to Figure 7 ), the corresponding cell after sweeping is a wedge-shaped body, and if the surface cell is a quadrilateral grid, the corresponding cell after sweeping is a hexahedron. The final swept body grid with common nodes can generate hexahedron-based common node grids with different cell sizes by setting different approximate global size sizes.

[0038] The present application aims at the deficiencies of the existing hexahedron grid division method in multi-entity common node grid generation. By automatically identifying the contact surface between multiple entities, automatically defining the sweep source surface, target surface and path, the problem of strong dependence on manual intervention and low automation degree of traditional sweep method is solved. By directly embedding the common node constraint algorithm in the grid division process, the grid of adjacent entities is strictly aligned, and the error accumulation caused by post-processing is avoided.

[0039] The computer program includes computer program code, which can be in the form of source code, object code, executable code, or some intermediate form. The computer readable medium can include at least one of any entity or device capable of carrying the computer program code, a storage medium, a computer memory, a Read-Only Memory (ROM), a Random Access Memory (RAM), an electric carrier signal, a telecommunications signal, and a software distribution package, such as a disk or a compact disk etc. In some jurisdictions, depending on the legislation and patent practice, a computer readable medium can not be an electric carrier signal and a telecommunications signal.

[0040] In the above embodiments, the description of each embodiment has its own focus, and the parts not described or recorded in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0041] Those skilled in the art can understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. A person skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0042] In the embodiments provided in the present application, it should be understood that the disclosed apparatus / equipment and method can be implemented in other ways. For example, the apparatus / equipment controller embodiments described above are only schematic, for example, the division of the modules or units is only a logical function division, and there can be another division manner in actual implementation, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or other forms.

[0043] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, i.e. they can be located in one place, or can be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the present embodiment.

[0044] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

[0045] The protection scope of the present application is not limited to this, any change or replacement of the technical solutions that can be thought of without creative labor should be covered in the protection scope of the present application. The protection scope of the present application is subject to the protection scope defined in the claims.

Claims

1. A multi-entity mesh generation method for converting target entities in geometric space into a parametric space mesh primarily composed of hexahedrons, characterized in that... , comprising: acquiring target entity information of a geometric space, dividing the target entity into a plurality of simple shape sub-entities in contact, each of which can be expressed by a general shape; extracting sub-entities in contact according to the geometric space information of each sub-entity, defining the side surface of the sub-entity in contact with other sub-entities as a contact surface, and defining two contact surfaces belonging to two sub-entities but in contact as a contact surface group; screening a contact surface as a main contact surface and other contact surfaces as auxiliary contact surfaces according to the area of the contact surface of each sub-entity, and constructing an information structure according to the main contact surface and the auxiliary contact surface; acquiring sweeping parameters and approximate global seeds according to the spatial geometric information of each sub-entity and the information structure data; establishing a sweeping surface sub-grid of each sub-entity in the parameter space according to the sweeping parameters and the approximate global seeds, the sub-grid being a quadrilateral grid, and each sub-entity corresponding to a sub-grid; acquiring a contact region of each contact surface group on the sub-grid according to the mapping relationship between each contact surface group and each sub-grid, and acquiring a contact cell of each sub-grid and a boundary cell around the outside of the contact cell according to the contact region; if the contact cell node positions of two sub-grids in contact are inconsistent, deleting the contact cell of one sub-grid, connecting the node adjacent to the deleted contact cell of the contact cell of the other sub-grid with the node adjacent to the side of the boundary cell of the deleted one sub-grid to form a transition cell with a common node; generating a global grid of the target entity according to the transition cell and each sub-grid, and acquiring a hexahedron-based grid of the target entity according to the global grid and the approximate global seeds.

2. The method of claim 1, wherein, The screening method of the main contact surface and the auxiliary contact surface includes screening the contact surface with the largest area as the main contact surface and the remaining contact surfaces as the auxiliary contact surfaces.

3. The method of claim 1, wherein, The information stored in the information structure includes main contact surface information, auxiliary contact surface information, entity information to which each contact surface belongs, and normal vector information pointing to the inside of each contact surface.

4. The method of claim 1, wherein, In the process of deleting the contact cell of one sub-grid, connecting the node adjacent to the deleted contact cell of the contact cell of the other sub-grid with the node adjacent to the side of the boundary cell of the deleted one sub-grid to form a transition cell with a common node, the contact cell mapping sub-grid of the sub-entity with the larger contact surface is taken as the deleted one.

5. The method of claim 4, wherein, In the process of connecting the node adjacent to the deleted contact cell of the contact cell of the other sub-grid with the node adjacent to the side of the boundary cell of the deleted one sub-grid to form a transition cell with a common node, the node adjacent to the side of the boundary cell actively connects the node adjacent to the side of the contact cell of the other sub-grid.

6. The method of claim 5, wherein, The process of the node adjacent to the side of the boundary cell actively connecting the node adjacent to the side of the contact cell of the other sub-grid includes matching and connecting the node adjacent to the side of the boundary cell with the node adjacent to the side of the contact cell by the nearest neighbor method to form an initial transition cell, and deleting the repeated lines of the initial transition cell according to the principle that each node of each boundary cell can only connect one contact cell node to obtain a transition cell.

7. An electronic device comprising a memory and a processor, characterized in that The memory stores a computer program, and the processor is configured to execute the method in any one of claims 1 to 6 by using the computer program.

8. A computer readable storage medium, characterized in that, The computer readable storage medium includes a stored program, wherein the program is executed by the processor to perform the method in any one of claims 1 to 6.

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