Multi-entity grid division method, electronic equipment and storage medium

Abstract

The invention discloses a multi-entity grid division method, electronic equipment and a storage medium, which are used for converting a target entity in a geometric space into a grid with a hexahedron as a main parameter space. According to the method and the device, the target entity is divided into a plurality of fruit entities with simple shapes, the contact surfaces among the multiple entities are automatically identified and extracted through multi-entity collaborative division by utilizing geometric feature matching and topological relation analysis, and the parameters capable of being swept are automatically defined; and manual selection of entities for Boolean operation for target surface extraction or one-by-one scanning is not needed. By adopting the connode algorithm provided by the invention, the connode constraint is applied in the grid division stage, and the connode grid is generated, so that the error accumulation caused by first division and then merging in the traditional method is avoided.

Description

Technical Field

[0001] The present invention relates to the field of automated simulation modeling, and in particular to a multi-entity grid division method, electronic equipment and storage medium. Background Art

[0002] In the field of automated simulation, hexahedral meshes are the preferred choice for simulating complex problems due to their high cell quality, good computational accuracy, and fast convergence. Compared to tetrahedral meshes, hexahedral meshes provide more accurate stress distribution, lower numerical dissipation, and significantly reduced solution time at the same computational scale. When simulating these problem scenarios, not only is the mesh quality of individual entities important, but also the need to ensure that the meshes of the contact surfaces of different entities share common nodes, meaning that adjacent meshes are strictly aligned at their junctions. Failure to do so can lead to computational errors or even solution failure.

[0003] Currently, hexahedral meshing methods include sweeping method, mapping method, decomposition-based method, etc. However, there are still problems such as low automation and low computational efficiency in the generation of multi-entity common-node meshes. Summary of the Invention

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

[0005] The method of the present application includes: a multi-entity meshing method for converting a target entity in a geometric space into a hexahedron-based mesh in a parameter space, comprising: The target entity information in the geometric space is obtained, and the target entity is divided into a plurality of simple-shaped sub-entities in contact, and each sub-entity can be expressed by a universal shape; based on the geometric space information of each sub-entity, the sub-entities in contact are extracted and the surface of the sub-entity in contact with the 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; based on the area of the contact surface of each sub-entity, one contact surface is selected as the main contact surface and the other contact surfaces are selected as auxiliary contact surfaces, and an information structure is constructed based on the main contact surface and the auxiliary contact surfaces; based on the spatial geometric information and information structure data of each sub-entity, the sweep parameters and the approximate global seed are obtained; based on the sweep parameters and the approximate global seed, a swept surface sub-grid of each sub-entity is established in the parameter space, and the The subgrid is a quadrilateral grid, and each sub-entity corresponds to a subgrid; according to the mapping relationship between each contact surface group and each subgrid, the subgrid with contact and the contact area corresponding to each contact surface group on the subgrid are obtained, and the contact cells of each subgrid and the boundary cells surrounding the outside of the contact cells are obtained according to the contact area; if the contact cell node positions of two subgrids with contact are inconsistent, the contact cells of one subgrid are deleted, and the nodes of the contact cells of the other subgrid adjacent to the deleted contact cells are connected with the adjacent side nodes of the boundary cells of the deleted subgrid to form transition cells with common nodes; based on the transition cells and each subgrid, the global grid of the target entity is generated, and the grid of the target entity mainly composed of hexahedrons is obtained based on the global grid and the approximate global seed.

[0006] Based on 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 auxiliary contact surfaces.

[0007] Based on the above method, further, the information structure stores information including primary contact surface information, secondary contact surface information, entity information to which each contact surface belongs, and normal vector information of each contact surface pointing to the interior of the entity.

[0008] Based on one of the above methods, further, in the process of deleting the contact cells of one sub-grid and connecting the nodes of the contact cells of the other sub-grid adjacent to the deleted contact cells with the side nodes adjacent to the boundary cells of the deleted sub-grid to form transition cells of common nodes, the contact cells of the sub-entity mapping sub-grid with the larger contact surface are used as the deleted party.

[0009] Based on one of the above methods, further, in the process of connecting the nodes in the contact cells of the other sub-grid adjacent to the deleted contact cells with the nodes on the adjacent side of the boundary cells of the deleted sub-grid to form transition cells of common nodes, the nodes on the adjacent side of the boundary cells are actively connected to the nodes on the adjacent side of the contact cells of the other sub-grid.

[0010] Based on one of the above methods, further, the process of actively connecting the nodes on the adjacent side of the boundary cell to the nodes on the adjacent side of the contact cell of the other sub-grid includes matching and connecting the nodes on the adjacent side of the boundary cell with the nodes on the adjacent side of the contact cell through the nearest neighbor method to form an initial transition cell, and deleting the repeated connections of the initial transition cell according to the principle that each boundary cell node can only be connected to one contact cell node to obtain the transition cell.

[0011] The present application also proposes an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor is configured to execute the method described in any of the above technical solutions through the computer program.

[0012] The present application also proposes a computer-readable storage medium, which includes a stored program, wherein the program executes the method described in any of the above technical solutions when executed by a processor.

[0013] This application divides the target entity into multiple simple-shaped sub-entities, and through multi-entity collaborative partitioning, uses geometric feature matching and topological relationship analysis to automatically identify and extract the contact surfaces between multiple entities and automatically define the parameters that can be swept, eliminating the need to manually select entities for Boolean operations to extract target surfaces or sweep them one by one. Using this application's common node algorithm, common node constraints are applied during the meshing phase to generate a common node mesh, avoiding the error accumulation of the traditional method of first dividing and then merging. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a flow chart of a method provided by an embodiment of the present invention; Figure 2 A schematic diagram of a sub-grid in one embodiment of the present application; Figure 3 This is a schematic diagram of two sub-grids with non-common nodes that are in contact in an embodiment of the present application; Figure 4 for Figure 3 A schematic diagram of an embodiment after deleting the contact grid of a square sub-grid; Figure 5 This is a schematic diagram of two sub-grids sharing a common node in one embodiment of the present application; Figure 6is a schematic diagram of a global grid of common nodes in another embodiment of the present application; Figure 7 This is a schematic diagram of a transition grid provided in an embodiment of the present application. DETAILED DESCRIPTION

[0015] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0016] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0017] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they can refer to fixed, removable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention in specific contexts. In the following description, for purposes of illustration and not limitation, specific details such as particular system structures and technologies are provided to facilitate a thorough understanding of the embodiments of the present application. However, those skilled in the art will appreciate that the present application may be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid obscuring the description of the present application with unnecessary detail. It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of the described features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof. It will also be understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0018] References to "one embodiment" or "some embodiments" throughout this specification mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in one or more embodiments of the present application. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in yet other embodiments" appearing in various places throughout this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically stated. The terms "including," "comprising," "having," and variations thereof mean "including but not limited to," unless otherwise specifically stated. The present invention will be described in further detail below with reference to the accompanying drawings.

[0019] refer to Figure 1, the implementation process of the method of the present application. The present invention relates to the field of automated simulation (such as finite element analysis, computational fluid dynamics, etc.), and specifically to how to divide and generate hexahedral meshes when converting entities into hexahedral meshes in simulation software, which can help simulation engineers to efficiently and quickly divide high-quality common-node meshes dominated by hexahedrons. In this embodiment, the technologies used in the meshing process include Open CASCADE Technology (literally translated as open cascade technology, which is 3D model-related software that can do 3D surface and entity modeling, CAD data exchange and visualization, and can be used to develop computer-aided design, computer-aided manufacturing / measurement or numerical simulation. Hereinafter referred to as OCCT). In this embodiment, a multi-entity meshing method is used to convert a target entity in a geometric space into a hexahedron-based mesh in a parameter space, comprising: obtaining target entity information in the geometric space, dividing the target entity into multiple simple-shaped sub-entities that are in contact, each sub-entity being expressible by a common shape, typically a simple cube; extracting sub-entities that are in contact based on the geometric space information of each sub-entity and defining the surface of the sub-entity that is in contact with the other sub-entity as a contact surface, and defining two contact surfaces that belong to two sub-entities but are in contact as a contact surface group; selecting one contact surface as a primary contact surface and the other contact surfaces as secondary contact surfaces based on the area of each sub-entity's contact surface, and constructing an information structure based on the primary and secondary contact surfaces. In this embodiment, it is necessary to first extract contact surface pairs, define the larger contact surface as the primary contact surface and the smaller contact surface as the secondary contact surface based on the area of the contact surfaces, and establish a contact surface information structure to store information on each pair of contact surfaces and their mapping relationship with the corresponding entities. According to the spatial geometric information and information structure data of each sub-entity, the sweep parameters and approximate global seeds are obtained; according to the sweep parameters and approximate global seeds, the sweep surface sub-grids of each sub-entity are established in the parameter space. The sub-grids are quadrilateral grids, and each sub-entity corresponds to a sub-grid. The sweep parameters include the sweep source surface, the target surface and the path. The above parameters are based on the contact surface extracted in the previous step and the mapping relationship with the sub-entity to obtain the source surface and the corresponding sub-entity that can be swept. This step mainly uses OCCT to judge the consistency of the entity sampling section, so as to judge whether the entity can be swept. If it can be swept, the centroid of the sampling section is extracted, and the B-spline curve is constructed as the sweep path through these centroids. According to the sweep parameters and the approximate global seeds, the sweep surface sub-grids of each sub-entity are established in the parameter space, and reference is made to Figure 2 In this application, one embodiment of a subgrid is a quadrilateral grid, and each sub-entity corresponds to a subgrid. This step mainly generates a quadrilateral grid of the swept surface, maps the contact surface from the geometric space to the parameter space, generates a plurality of grid nodes with similar spacing through an approximate global seed, and then associates the grid nodes to form a quadrilateral grid, such as Figure 2-3 In order to assist in the description of this application, the nodes of the grid are shown as circles in bold. Figure 3 , the contact surfaces of the two sub-entities are in contact, and after each generates its own quadrilateral mesh, further processing is required to ensure that the two contact surfaces share common nodes. Figure 3 The two sub-grids are non-common node grids. Therefore, this application obtains the sub-grids with contact and the contact areas corresponding to the contact surface groups 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 surrounding the outside of the contact cells according to the contact areas; refer to Figure 4 If the contact cell nodes of two contacting sub-grids are not in the same position, delete the contact cell of one sub-grid and connect the nodes of the contact cell of the other sub-grid adjacent to the deleted contact cell with the nodes adjacent to the boundary cells of the deleted sub-grid to form transition cells with common nodes, such as Figure 5 The above steps mainly remove all contact areas (i.e. contact cells, the set of all contacting grid cells in the subgrid) from the contact surface of one sub-entity that are in contact with the contact surface of another sub-entity, so that there will be pores in the middle of the contact surface of the sub-entity (refer to Figure 4 In the case of non-common nodes, after one sub-grid cuts out the gaps between the boundary cells and the contact cells of the other sub-grid, this grid with gaps is merged with the other sub-grid to obtain a large grid consisting of two sub-grids with gaps to be filled, and then refer to Figure 5 , generate transition cells to fill the gaps between the two sub-grids, and obtain a large grid after the two sub-grids are connected together. Connect the two sub-grids through transition cells to achieve the connection of the two sub-grids' common nodes. On this basis, all sub-grids are connected through corresponding transition cells to obtain the global grid of the target entity. Based on the global grid and the approximate global seed, the grid of the target entity is mainly hexahedral; in this step, if Figure 6 With a global mesh and an approximate global seed, the sweeping step size can be obtained by combining the sweeping path. Combined with the global mesh of quadrilaterals with common nodes obtained in the previous step, a hexahedral mesh of the target entity with hexahedrons as the main component can be generated along the sweeping path. This application directly embeds the common node algorithm in the mesh generation stage and adopts the hole patching + annular gap filling technology to achieve 100% node matching accuracy on the contact surfaces of adjacent entities. Compared with traditional post-processing methods (such as the node merging function in ANSYS Workbench), it avoids the error accumulation caused by multiple iterations.

[0020] Based on the above embodiment, the present application further improves the method for selecting the primary contact surface and the secondary contact surface, including selecting the contact surface with the largest area as the primary contact surface and the remaining contact surfaces as secondary contact surfaces. In this embodiment, using the contact surface with the largest area as the primary contact surface and the remaining contact surfaces as secondary contact surfaces facilitates the construction of the information structure and improves computational efficiency.

[0021] Based on one or more of the above embodiments, the present application further improves upon this, wherein the information structure stores information including primary contact surface information, secondary contact surface information, entity information to which each contact surface belongs, and normal vector information of each contact surface pointing within the entity. In this embodiment, the above information can effectively improve the determination of the sweep source surface, target surface, and path during the sweeping process.

[0022] Based on one or more of the above embodiments, the present application further improves the process of deleting the contact cells of one sub-grid and connecting the nodes of the contact cells of the other sub-grid adjacent to the deleted contact cells with the adjacent side nodes of the boundary cells of the deleted sub-grid to form transition cells with a common node, and using the contact cells of the sub-grid mapped by the sub-entity with a larger contact surface as the deleted party. In the present application, using the sub-grid mapped by the sub-entity with a larger contact surface area as the deleted party can make the contact cells and the boundary cells as much as possible located in the same plane, thereby improving the generation efficiency of the transition cell ring.

[0023] Based on one or more of the above embodiments, this application is further improved. Figure 7 In the process of connecting the nodes of the contact cells of the other sub-grid adjacent to the deleted contact cells with the nodes adjacent to the boundary cells of the deleted sub-grid to form transition cells of common nodes, the nodes adjacent to the boundary cells are actively connected to the nodes adjacent to the contact cells of the other sub-grid.

[0024] Based on one or more of the above-described embodiments, the present application further improves upon this process, wherein the process of actively connecting the nodes on the adjacent side of the boundary cell to the nodes on the adjacent side of the contact cell of the other sub-grid includes matching and connecting the nodes on the adjacent side of the boundary cell with the nodes on the adjacent side of the contact cell using the nearest neighbor method to form an initial transition cell. Based on the principle that each boundary cell node can only be connected to one contact cell node, duplicate connections in the initial transition cell are deleted to obtain the transition cell. In this embodiment, while ensuring that the two sub-grids have common nodes connected, the proportion of hexahedral cells is increased, and only the transition cell region contains a small number of wedge-shaped or tetrahedral cells.

[0025] The present application also discloses an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor is configured to execute the steps described in any one of the above method embodiments through the computer program.

[0026] The present application also discloses a computer-readable storage medium, which includes a stored program, wherein the program executes the steps described in any one of the above method embodiments when executed by a processor.

[0027] The present application is further described below in terms of computer program operation.

[0028] This embodiment proposes a rapid hexahedral meshing method for target entities, primarily based on shared nodes, explained within the context of computational geometry and CAE (Computer-Aided Engineering) simulation pre-processing. This embodiment uses multiple contacting cubes as an example to illustrate the implementation of the technical solution. OCCT is used for feature extraction and geometry processing, with each subentity represented by a TopoDS_Shape (generic shape). VTK 9.3 (Visualization Toolkit 3D computer graphics software) is used to construct the mesh data, and the core algorithm is written in C++11.

[0029] This embodiment includes extracting the bounding box of each sub-entity TopoDS_Shape (general shape) through OCCT, first determining whether the bounding boxes intersect, if the bounding boxes intersect, then traversing all the faces TopoDS_Face of the two TopoDS_Shapes, calculating whether their normal vectors are parallel, if the normal vectors are parallel, then calculating the minimum distance between the two faces, if the distance is less than 1e -6 , then it is determined that the two faces are in contact, the sub-entity corresponding to this face is recorded, and the area of the contact face is obtained. The face with a larger area is defined as the main contact face, and the face with a smaller area is defined as the auxiliary contact face. The surface information structure is constructed to store the contact face information, the main contact face and a series of auxiliary contact faces, as well as the sub-entity to which each contact face belongs, and the normal vector of the contact face pointing to the inside of the corresponding sub-entity. According to the outer bounding box of the sub-entity and the normal vector of the contact face, as well as the approximate global size of the defined grid unit, a sampling interval is obtained. The sampling section of the entity is obtained by sampling along the normal direction of the sub-entity surface, and the center of mass of each section is calculated, and the bounding box and area of the section are calculated. If the area of each section and the length and width of the bounding box are consistent with the data of the previous face within 1e -6If the sub-entity is within , the sub-entity is determined to be a sweepable body. If the sub-entity is a sweepable body, the original contact surface is set as the sweep source surface, the last section is set as the target surface, the centroids of each section are fitted to a B-spline curve, and this B-spline curve is set as the sweep path. The contact surface TopoDS_Face is mapped to the coordinate system parameter domain. Based on the set approximate global seed size, uniform mesh nodes are generated from top to bottom and right to left. Tetrahedral element data is then constructed according to the element structure, and finally a quadrilateral mesh is generated for each sub-entity's swept surface. Each contact surface is processed according to the contact status of each sub-entity. The boundaries of all auxiliary contact surfaces in the contact surface are obtained to obtain boundary cell rings, and the proximal cell rings are also extracted. If the node positions of the boundary cell rings of two contacting sub-meshes are inconsistent, the boundary cell ring of one sub-mesh is deleted, and the nodes on the proximal side of the boundary cell ring of the other sub-mesh are connected to the nodes on the proximal side of the deleted sub-mesh to form a transition cell ring with common nodes. After the subgrids are merged and connected into a large grid through the transition cell ring, they are smoothed by Laplace and the distribution of nodes is optimized to obtain the final global grid, as shown in Figure 2 After the global mesh is generated, if the mesh element is a triangle mesh (only exists on the transition cell ring, refer to Figure 7 ), the corresponding elements after the sweep are wedge-shaped. If the surface elements are quadrilateral, the corresponding elements after the sweep are hexahedrons. The resulting swept common-node volume mesh can be generated with different element sizes, mainly hexahedrons, by setting different approximate global sizes.

[0030] This application addresses the shortcomings of existing hexahedral meshing methods in generating multi-entity common-node meshes. By automatically identifying the contact surfaces between multiple entities and automatically defining the sweep source surface, target surface, and path, it solves the problems of traditional sweeping methods that are highly dependent on manual intervention and have a low degree of automation. By directly embedding the common-node constraint algorithm in the meshing process, it ensures that adjacent entity meshes are strictly aligned, avoiding error accumulation caused by post-processing.

[0031] The present application implements all or part of the processes in the above-mentioned embodiment method by instructing the relevant hardware through a computer program. The computer program includes computer program code, which can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include at least: any entity or device capable of carrying computer program code to a device / electronic device, recording medium, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium. For example, a USB flash drive, mobile hard disk, magnetic disk or optical disk. In some jurisdictions, based on legislation and patent practice, computer-readable media cannot be electric carrier signals and telecommunication signals.

[0032] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0033] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0034] In the embodiments provided in the present application, it should be understood that the disclosed devices / electronic devices and methods can be implemented in other ways. For example, the device / electronic device controller embodiments described above are merely schematic. For example, the division of the modules or units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0035] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0036] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application 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. 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 various embodiments of the present application, and should all be included in the scope of protection of the present application.

[0037] The scope of protection of the present invention is not limited to this, and any changes or replacements of the technical solutions that can be thought of without creative work should be included in the scope of protection of the present invention. The scope of protection of the present invention shall be based on the scope of protection defined in the claims.

Claims

1. A multi-entity meshing method for converting a target entity in a geometric space into a hexahedron-based mesh in a parameter space, characterized in that ,include: Obtaining target entity information in a geometric space, dividing the target entity into a plurality of simple-shaped sub-entities that are in contact, each of which can be expressed using a universal shape; According to the geometric space information of each sub-entity, the sub-entities that are in contact are extracted and the surface of the sub-entity that is in contact with other sub-entities is defined as the contact surface. The two contact surfaces that belong to two sub-entities but are in contact are defined as a contact surface group. According to the area of the contact surface of each sub-entity, one contact surface is selected as the main contact surface, and the other contact surfaces are selected as auxiliary contact surfaces, and an information structure is constructed based on the main contact surface and the auxiliary contact surfaces; Obtain sweep parameters and approximate global seeds based on the spatial geometric information and information structure data of each sub-entity; According to the sweep parameters and the approximate global seed, a swept surface subgrid of each sub-entity is established in the parameter space, wherein the subgrid is a quadrilateral grid, and each sub-entity corresponds to a subgrid; According to the mapping relationship between each contact surface group and each sub-grid, the sub-grids with contact and the contact area corresponding to each contact surface group on the sub-grid are obtained, and the contact cells of each sub-grid and the boundary cells surrounding the contact cells are obtained according to the contact area; If the contact cell nodes of two contacting subgrids are not in the same position, delete the contact cell of one subgrid, and connect the nodes of the contact cell of the other subgrid adjacent to the deleted contact cell with the nodes adjacent to the boundary cells of the deleted subgrid to form transition cells with common nodes. The global grid of the target entity is generated according to the transition cells and each subgrid, and the hexahedral grid of the target entity is obtained according to the global grid and the approximate global seed.

2. The method according to claim 1, characterized in that The method of screening 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 auxiliary contact surfaces.

3. The method according to claim 1, characterized in that The information structure stores information including primary contact surface information, secondary contact surface information, entity information to which each contact surface belongs, and normal vector information of each contact surface pointing to the interior of the entity.

4. The method according to claim 1, wherein In the process of deleting the contact cells of one sub-grid and connecting the nodes of the contact cells of the other sub-grid adjacent to the deleted contact cells with the side nodes adjacent to the boundary cells of the deleted sub-grid to form transition cells with common nodes, the contact cells of the sub-entity mapping sub-grid with the larger contact surface are used as the deleted party.

5. The method according to claim 4, characterized in that In the process of connecting the nodes of the contact cells of the other sub-grid adjacent to the deleted contact cells with the nodes on the adjacent side of the boundary cells of the deleted sub-grid to form transition cells with common nodes, the nodes on the adjacent side of the boundary cells are actively connected to the nodes on the adjacent side of the contact cells of the other sub-grid.

6. The method according to claim 5, characterized in that The process of actively connecting the nodes on the adjacent side of the boundary cell to the nodes on the adjacent side of the contact cell of the other sub-grid includes matching and connecting the nodes on the adjacent side of the boundary cell with the nodes on the adjacent side of the contact cell through the nearest neighbor method to form an initial transition cell, and deleting the repeated connections of the initial transition cell based on the principle that each boundary cell node can only be connected to one contact cell node to obtain a transition cell.

7. An electronic device comprising a memory and a processor, characterized in that: A computer program is stored in the memory, and the processor is configured to execute the method according to any one of claims 1 to 6 through 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 a processor to perform the method according to any one of claims 1 to 6.

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