A method, apparatus, device and application for modeling porous structures

Abstract

This invention discloses a method, apparatus, device, and application for modeling porous structures, relating to the fields of computer-aided design and additive manufacturing. The method involves constructing a cuboid region based on the target part structure, changing the distance between the vertices of the isosurface along the x-axis and y-axis respectively to modify the contours of the isosurface in each direction, and constructing the target part based on the modified isosurface. This ensures that the integrity of the minimal surface unit cell is maintained at the boundary of the porous support, realizing the establishment of a boundary-complete complex porous model using minimal surfaces, and providing a new direction for the design of porous supports with complex contours.

Description

Technical Field

[0001] This invention relates to the fields of computer-aided design and additive manufacturing technology, and in particular to a method, apparatus, equipment and application for modeling porous structures. Background Technology

[0002] To achieve the performance required for ideal biomedical scaffolds, porous structures have emerged as a promising option due to their large surface area and low density, which avoids stress shielding issues. Furthermore, the surface of porous structures can be modified or filled with active substances such as cells and growth factors. The development of 3D printing has made it possible to break through traditional subtractive manufacturing-based design methods and realize the design, manufacturing, and application of personalized porous structures. Leveraging the excellent mechanical properties of lattice structures, researchers have conducted numerous design, manufacturing attempts, and performance evaluations. However, in stress distribution analysis and additive manufacturing processes, traditional lattice structures exhibit problems such as premature stress concentration under applied loads and early failure due to the limitations of 3D printing technology.

[0003] Triply Periodic Minimal Surface (TPMS) structures, with their zero average curvature, reduce stress concentration and achieve 100% internal permeability, enabling higher weight reduction targets without sacrificing porosity. This makes them a high-performance porous structure model. Furthermore, this structure maintains stable self-support and a relatively consistent cross-sectional area during additive manufacturing, resulting in better printability.

[0004] When the period T is the same in the X, Y, and Z directions, the minimal surface structure is a unit cell within a cubic domain. However, for practical applications, it is necessary to construct porous scaffolds with complex contours. Existing methods include: one is to obtain a porous scaffold by performing Boolean intersection between the scaffold and the minimal surface structure; the other is to mesh the scaffold with a hexahedron and map it using isoparametric elements. However, these methods have significant limitations. For the first method, Boolean operations inevitably lead to incomplete unit cells at the outer contour boundaries of the scaffold, and the incompleteness of these boundary unit cells will adversely affect the load-bearing capacity of the scaffold. For the second method, firstly, it is difficult to perform full hexahedron meshing with appropriate unit cell size for complex models; secondly, not all types of TPMS can be obtained using this method.

[0005] like Figure 1 For three types of unit cells, P, D, and G, with a period T of 2, since the contours and dimensions of the six end faces of P and D units are consistent, as shown below... Figure 2 and Figure 3 as well as Figure 4These are slices taken from the center of P, D, and G, and slices at the |x|=1, |y|=1, and |z|=1 sections, respectively. From these slices, it can be seen that the contours of sections P and D are consistent, and any one of these sections can connect with the other five sections to form a continuous structure. However, for the G-type minimal surface, the contours of its sections are inconsistent. For example, in section 4, the contours of sections x=1 and x=-1 are consistent, but not with the other four sections. When this type of unit cell connects with surrounding unit cells to form a whole, the placement of each unit cell is restricted by the surrounding unit cells, so each unit cell can only connect with other unit cells in one placement manner. For the P and D-type minimal surfaces, any placement method can connect with surrounding unit cells. During shape function mapping, the cross-sections connecting some hexahedral elements and surrounding elements may change. For example, a y=1 cross-section might need to connect with a z=1 or x=1 cross-section. This would cause the G-type unit cell to disconnect from its surrounding units, preventing it from forming a unified structure. Therefore, it's impossible to obtain a G-type porous scaffold using hexahedral meshes combined with shape function mapping. For P and D unit cells with identical shape profiles and orientations across all six cross-sections, connections with surrounding units are possible even if the connecting cross-sections change. A circular cross-section mesh is used, and mapping is performed using G and P respectively. Figure 5 As can be seen, for P-cells, the connection remains good even after the cross-section of adjacent cells changes.

[0006] Depend on Figure 5 In the case of the G-cell shown, the connection cross section between a cell and its surrounding cells changes at some locations, preventing the cell from connecting correctly with its neighbors. Therefore, there are two limitations to using hexahedral meshing combined with shape function transformation for porous structure modeling: (1) high-quality hexahedral meshing is difficult to achieve for complex models; (2) shape function transformation is not applicable to G-cells. Therefore, this method also has limitations in the selection of TPMS cell types.

[0007] In summary, it can be seen that finding a porous scaffold suitable for all types of minimal surface structures with complete unit cells at the boundary is a problem that needs to be solved. Summary of the Invention

[0008] The purpose of this invention is to provide a porous structure modeling method, apparatus, and device to solve the problem that the existing technology does not have a suitable method for all types of minimal curved surface structures, and cannot guarantee the integrity of boundary unit cells for different types of structures.

[0009] To address the aforementioned technical problems, this invention provides a method for modeling porous structures, comprising:

[0010] S1. Based on the target part structure, determine a cuboid region whose size is the smallest enclosed area of ​​the target part structure, take the direction with the largest size as the z-axis, and the other two directions as the x-axis and y-axis respectively, and establish the first isosurface within the cuboid region;

[0011] S2. Multiply the y-coordinates of the first isosurface points along the y-axis by a first scaling factor to modify the distance between vertices in the first isosurface, thereby obtaining a second isosurface;

[0012] S3. Multiply the x-coordinates of the points on the second isosurface by a second scaling factor along the x-axis to modify the distance between vertices in the second isosurface, thereby obtaining a third isosurface;

[0013] S4. Determine whether the contour has changed along the z-axis. If the contour section is consistent along the z-axis, generate the target part based on the third isosurface. If the contour section changes uniformly along the z-axis, scale the section according to different z coordinates to generate the target part. If the size and shape of the contour section change along the z-axis, repeat steps S2, S3, and S4 according to different z coordinates until a fourth isosurface is obtained where the size and shape of the section do not change. Use the fourth isosurface to generate the target part.

[0014] Preferably, the step of establishing the first isosurface within the cuboid region includes:

[0015] Based on the target part structure, its internal rectangular region is determined, ensuring that two or four points of the rectangle fall on the contour. The minimum surface unit cell size is determined by combining the rectangle's side length with its z-axis height.

[0016] Preferably, the step of multiplying the y-coordinates of the first isosurface points along the y-axis by a first scaling factor to modify the distance between vertices in the first isosurface to obtain a second isosurface includes:

[0017] The first scaling factor is determined by dividing the distance of the line segment inside the rectangular boundary of the straight line passing through the first isosurface and parallel to the y-axis by the side length of the rectangle.

[0018] Preferably, the step of multiplying the x-coordinates of the points on the second isosurface along the x-axis by a second scaling factor to modify the distance between vertices in the second isosurface to obtain a third isosurface includes:

[0019] The second scaling factor is determined by dividing the distance of the line segment inside the rectangular boundary of the line passing through the second isosurface and parallel to the x-axis by the side length of the rectangle.

[0020] Preferably, the formulas for calculating the first scaling factor and the second scaling factor are as follows:

[0021]

[0022] in, The first scaling factor is... The length of the secant line between the target part's cross-sectional profile curve and the straight line X=x within the profile. y is the length of the cuboid region containing the first isosurface along the y-axis.

[0023]

[0024] in, This is the second scaling factor. The length of the secant line between the target part's cross-sectional profile curve and the straight line Y=y that lies inside the profile. Let x be the length of the cuboid region containing the second isosurface along the x-axis. , The original y-coordinate is transformed into the following coordinates. y is the y-coordinate of the original isosurface.

[0025] Preferably, the first isosurface is a minimal surface composed of points within the cuboid.

[0026] Preferably, the first isosurface modeling formula is:

[0027]

[0028] Where F is the modeling expression for the first isosurface. For a period of time, , , It is a function variable.

[0029] The present invention also provides a porous structure modeling apparatus, comprising:

[0030] The model building module is used to determine a cuboid region whose size matches the target part structure based on the target part structure, taking the direction with the largest size as the z-axis and the other two directions as the x-axis and y-axis respectively, and establishing the first isosurface within the cuboid region.

[0031] The y-axis contour modification module is used to modify the distance between vertices in the first isosurface by multiplying the y-coordinate of the first isosurface point by a first scaling factor along the y-axis to obtain a second isosurface.

[0032] The x-axis contour modification module is used to modify the distance between vertices in the second isosurface by multiplying the x-coordinate of the second isosurface point by a second scaling factor along the x-axis to obtain a third isosurface.

[0033] The target part generation module is used to determine whether the contour changes along the z-axis. If the contour section is consistent along the z-axis, the target part is generated based on the third isosurface. If the contour section changes uniformly along the z-axis, the section is scaled according to different z coordinates to generate the target part. If the size and shape of the contour section change along the z-axis, steps S2, S3, and S4 are repeated according to different z coordinates until a fourth isosurface is obtained in which the size and shape of the section do not change. The target part is generated using the fourth isosurface.

[0034] The present invention also provides a porous structure modeling device, comprising:

[0035] Memory, used to store computer programs;

[0036] A processor is used to implement the steps of the porous structure modeling method described above when executing the computer program.

[0037] The present invention also provides an application of the porous structure modeling method described above in biomedical scaffolds.

[0038] The present invention provides a porous structure modeling method that constructs a cuboid region based on the target part structure, changes the distance between the vertices of the isosurface along the x-axis and y-axis respectively, and modifies the contour of the isosurface along each direction. Based on the modified isosurface, the target part is constructed, ensuring that the integrity of the minimal surface unit cell is maintained at the boundary of the porous support. This realizes the establishment of a complex porous model with complete boundary using minimal surfaces, providing a new direction for the design of porous supports with complex contours. Attached Figure Description

[0039] To more clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 Diagrams of three types of unit cell structures: P, D, and G;

[0041] Figure 2 This is a cross-sectional view of a P-cell.

[0042] Figure 3 This is a cross-sectional view of a D-cell unit cell;

[0043] Figure 4 This is a cross-sectional view of a G unit cell;

[0044] Figure 5 Hexahedral mesh and G,P unit cell mapping diagram;

[0045] Figure 6 A flowchart of a first specific embodiment of a porous structure modeling method provided by the present invention;

[0046] Figure 7 A flowchart of a porous structure modeling method;

[0047] Figure 8 This is an isosurface map of the rectangular prism region;

[0048] Figure 9 An isosurface plot showing how two horizontal edges become circular arcs;

[0049] Figure 10 The isosurface plot after the two vertical sides are transformed into arcs;

[0050] Figure 11 To obtain an STL model of a cylinder with thickness by smoothing and offsetting the isosurface;

[0051] Figure 12 To adjust the distance between the two horizontal edges;

[0052] Figure 13 To adjust the cuboid region to a regular hexagonal shape;

[0053] Figure 14 To adjust the size of the isosurface section along the z-axis;

[0054] Figure 15 To obtain a pyramidal STL model with thickness by smoothing and offsetting the isosurface;

[0055] Figure 16 This is a structural block diagram of a porous structure modeling device provided in an embodiment of the present invention. Detailed Implementation

[0056] The core of this invention is to provide a method, apparatus, device and application for modeling porous structures, which realizes the establishment of complex porous models with complete boundaries using minimal curved surfaces.

[0057] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0058] Please refer to Figure 6 , Figure 7 , Figure 6 A flowchart of a first specific embodiment of a porous structure modeling method provided by the present invention; the specific operation steps are as follows:

[0059] S1. Based on the target part structure, determine a cuboid region whose size is the smallest enclosed area of ​​the target part structure, take the direction with the largest size as the z-axis, and the other two directions as the x-axis and y-axis respectively, and establish the first isosurface within the cuboid region;

[0060] To determine the cuboid region, first adjust the position of the target part so that the direction with the largest dimension is used as the z-axis, and the other two directions are used as the x-axis and y-axis, respectively. Based on the part's x and y contours, determine the rectangular region located within it. This step requires determining the position and side length of the rectangle based on the actual cross-section. For example, for a circular cross-section, it is an inscribed square; for a regular hexahedron, a square region with its side length is selected; for more complex contours, ensure that two or four points of the rectangle fall on the contour. A cuboid region is determined by combining the long-direction side length with the z-direction height. The minimum surface unit cell size is determined based on the determined side length of the cuboid region, and isosurface functions in MATLAB are used to create isosurfaces within the cuboid region.

[0061] The rectangular region is the minimum enclosing region of the target part, or the inscribed rectangle of the regular model. The length and width of the rectangle can be adjusted appropriately according to the suitable unit cell size and the number of periods of the minimal surface, so that the target model can still be obtained by using this method.

[0062]

[0063] Where F is the modeling expression for the first isosurface. For a period of time, , , It is a function variable.

[0064] S2. Multiply the y-coordinates of the first isosurface points along the y-axis by a first scaling factor to modify the distance between vertices in the first isosurface, thereby obtaining a second isosurface;

[0065] Based on the boundary profile of the support section, multiply the y-coordinates of all points on the isosurface by a scaling factor along the y-direction. Modify the scaling factor of the distance between vertices in the isosurface. The value is determined by dividing the distance of the line segment inside the rectangle's boundary by the side length of the square, where the line passing through the point and parallel to y is located. Different scaling factors are applied to vertices at different positions using MATLAB software. This allows for the modification of the contour of the isosurface along the y-direction.

[0066]

[0067] in, The first scaling factor is... The length of the secant line between the target part's cross-sectional profile curve and the straight line X=x within the profile. y is the length of the cuboid region containing the first isosurface along the y-axis.

[0068] S3. Multiply the x-coordinates of the points on the second isosurface by a second scaling factor along the x-axis to modify the distance between vertices in the second isosurface, thereby obtaining a third isosurface;

[0069] Based on the boundary profile of the support section, the x-coordinates of some vertices on the isosurface are multiplied by a scaling factor along the x-direction. Modifying the distances between vertices in the isosurface does not apply to all vertices, but rather to all vertices that remain within the square region after the second step, and the scaling factor of these vertices. The value is determined by dividing the distance of the line segment inside the rectangle's boundary by the side length of the square, where the line passing through the point and parallel to x is located. Different scaling factors are applied to vertices at different positions using MATLAB software. This allows for the modification of the isosurface along the x-contour.

[0070]

[0071] in, This is the second scaling factor. The length of the secant line between the target part's cross-sectional profile curve and the straight line Y=y that lies inside the profile. Let x be the length of the cuboid region containing the second isosurface along the x-axis. , The original y-coordinate is transformed into the following coordinates. y is the y-coordinate of the original isosurface.

[0072] S4. Determine whether the contour has changed along the z-axis. If the contour section is consistent along the z-axis, generate the target part based on the third isosurface. If the contour section changes uniformly along the z-axis, scale the section according to different z coordinates to generate the target part. If the size and shape of the contour section change along the z-axis, repeat steps S2, S3, and S4 according to different z coordinates until a fourth isosurface is obtained where the size and shape of the section do not change. Use the fourth isosurface to generate the target part.

[0073] For models with consistent z-sections, no operation is performed; this step is skipped.

[0074] For cross-sections whose dimensions change along the z-axis but whose contours remain unchanged, i.e., the z-section is a similar figure:

[0075] For this model, it is only necessary to determine the scaling factor for each z-section based on linear interpolation, and then scale the x and y coordinates of the points on the third isosurface to obtain the fourth isosurface. The scaling factor is then determined using interpolation based on the maximum cross-sectional area S1, the minimum cross-sectional area S2, and the current cross-sectional area S. ;

[0076]

[0077] Where z is the z-coordinate of the cross section. , Let x and y coordinates be the obtained fourth isosurface. , .

[0078] For such complex models, the cross-sections are neither identical nor similar, making it impossible to adjust the cross-sectional contours using scaling. Therefore, it is necessary to slice the model along the z-axis, select a layer thickness t, slice the model, and then repeat steps two and three for each slice. Finally, combine the points of each cross-section to obtain a new fourth isosurface.

[0079] This embodiment provides a porous structure modeling method. For porous structures with complex contours established by minimal surfaces, a new method for modeling complex contours is achieved by changing the distance between vertices of the rectangular region isosurface. This method ensures that the integrity of the minimal surface unit cell is maintained at the boundary of the porous support, and realizes the establishment of a complex porous model with complete boundary using minimal surfaces.

[0080] Based on the above embodiments, this embodiment uses specific experiments to illustrate the method, and the specific operation steps are as follows:

[0081] ① A cylindrical porous support with a diameter of 10mm and a height of 15mm;

[0082] Step 1: As Figure 8 As shown, based on a diameter of 10mm, the unit cell size is determined to be 2.5mm, and the cuboid region contains three periodic unit cells in the x and y directions and six periodic unit cells in the z direction. The dimensions of the cuboid region are 7.5mm*7.5mm*15mm. A three-dimensional mesh is generated using the meshgrid function in MATLAB, and three-dimensional volume data is generated. The isosurface function is used to extract the Gyroid type unit cell isosurface within this region.

[0083] Step 2: As Figure 9 As shown, the x-coordinates of all points on the isosurface generated in the first step are used as the criteria, and the ratio of the chord length of the circle passing through x to the side length of the square is used as the scaling factor. Multiply the y-coordinate of all points by a scaling factor This is done by adjusting the distance between the vertices, transforming its two horizontal sides into two arcs.

[0084] Step 3: As Figure 10 As shown, using the y-coordinates of all vertices within the cuboid region in step 1 in the isosurface generated in the second step as the criterion, the x-coordinates of all points are multiplied by a scaling factor. Its two vertical sides are transformed into two circular arcs.

[0085] Step 4: Adjust the diameter of the circle to 7.5 mm. Scaled to 10, the scaling factor K3 is 10 and 7.5 for the diameter. The ratio of x and y is multiplied by the scaling factor K3 to obtain the final isosurface.

[0086] Step 5: As Figure 11 As shown, the isosurfaces in the fourth step are exported in STL format and then subjected to subsequent smoothing and offset processing for 3D printing.

[0087] ② A pyramid with an upper base diameter of 8mm, a lower base diameter of 10mm, a height of 10mm, and 6 edges;

[0088] Step 1: Based on the pyramidal section, determine the G-type isosurfaces within the cuboid domain as follows: x-axis range -2.5~2.5, y-axis range -3.75~3.75, z-axis range -5~5, which is 5mm*7.5mm*10mm. Use MATLAB's meshgrid function to divide the three-dimensional mesh and generate three-dimensional volume data. Use the isosurface function to extract the G-type unit cell isosurfaces within this region.

[0089] Step 2: As Figure 12 As shown, using the x-coordinates of all points on the isosurface generated in the first step as the criterion, the y-coordinates of all points are multiplied by a scaling factor. Adjustments were made, changing the distance between its two horizontal sides from 7.5 to... .

[0090] Step 3: As Figure 13 As shown, using the y-coordinate of all points on the isosurface generated in the second step as a criterion, the x-coordinate of all points is multiplied by a scaling factor. Adjustments were made to change the distance between its two horizontal sides, transforming the cross-section into a regular hexagon.

[0091] Step 4: As Figure 14 As shown, the cross-section size changes from the bottom to the top along the z-direction, with the diameter changing from 10mm to 8mm. The cross-section is scaled by multiplying the x-coordinate and y-coordinate of all points by the scaling factor corresponding to the cross-section. The x and y coordinates are reduced using this scaling factor to obtain the third isosurface, and finally the model of the cross section varies along z is obtained.

[0092] Step 5: As Figure 15 As shown, the isosurfaces in the fourth step are exported in STL format and then subjected to subsequent smoothing and offset processing for 3D printing.

[0093] This embodiment provides a porous structure modeling method. The method is experimentally tested using specific data. A cuboid region is constructed based on the target part structure. The distance between the vertices of the isosurface is changed along the x-axis and y-axis respectively to modify the contour of the isosurface in each direction. The target part is constructed based on the modified isosurface, ensuring that the integrity of the minimal surface unit cell is maintained at the boundary of the porous support. This realizes the establishment of a complex porous model with complete boundary using minimal surfaces, providing a new direction for the design of porous supports with complex contours.

[0094] Please refer to Figure 16 , Figure 16 A structural block diagram of a porous structure modeling device provided in an embodiment of the present invention; the specific device may include:

[0095] The model building module 100 is used to determine a cuboid region whose size matches the target part structure based on the target part structure, taking the direction with the largest size as the z-axis and the other two directions as the x-axis and y-axis respectively, and to establish the first isosurface within the cuboid region.

[0096] The y-axis contour modification module 200 is used to modify the distance between vertices in the first isosurface by multiplying the y-coordinate of the first isosurface point by a first scaling factor along the y-axis to obtain a second isosurface.

[0097] The x-axis contour modification module 300 is used to modify the distance between vertices in the second isosurface by multiplying the x-coordinate of the second isosurface point by a second scaling factor along the x-axis to obtain a third isosurface.

[0098] The target part generation module 400 is used to determine whether the contour changes along the z-axis direction. If the contour cross-section is consistent along the z-axis direction, the target part is generated based on the third isosurface. If the contour cross-section changes uniformly along the z-axis direction, the cross-section is scaled according to different z coordinates to generate the target part. If the size and shape of the contour cross-section change along the z-axis direction, steps S2, S3, and S4 are repeated according to different z coordinates until a fourth isosurface is obtained where the size and shape of the cross-section have changed. The target part is generated using the fourth isosurface.

[0099] This embodiment provides a porous structure modeling device for implementing the aforementioned porous structure modeling method. Therefore, the specific implementation of the porous structure modeling device can be found in the embodiment section of the porous structure modeling method above. For example, the model building module 100, the y-axis contour modification module 200, the x-axis contour modification module 300, and the target part generation module 400 are used to implement steps S1, S2, S3, and S4 in the aforementioned porous structure modeling method, respectively. Therefore, the specific implementation can be referred to the description of the corresponding embodiments, which will not be repeated here.

[0100] A specific embodiment of the present invention also provides a porous structure modeling device, comprising: a memory for storing a computer program; and a processor for executing the computer program to implement the steps of the porous structure modeling method described above.

[0101] A specific embodiment of the present invention also provides an application of a porous structure modeling method in biomedical scaffolds.

[0102] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0103] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0104] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0105] The present invention provides a detailed description of a porous structure modeling method, apparatus, device, and application. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of these embodiments are merely illustrative and are intended to aid in understanding the method and core concepts of the invention. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims.

Claims

1. A method for modeling porous structures, characterized in that, include: S1. Based on the target part structure, determine a cuboid region whose size matches the target part structure, take the direction with the largest size as the z-axis, and the other two directions as the x-axis and y-axis respectively, and establish the first isosurface within the cuboid region; based on the target part structure, determine its internal rectangular region, ensuring that two points or four points of the rectangle fall on the cross-sectional contour of the target part, and determine the minimum surface unit cell size by combining the side length of the rectangle with the height in the z-direction; S2. Multiply the y-coordinate of the first isosurface point along the y-axis by a first scaling factor to modify the distance between vertices in the first isosurface, thereby obtaining a second isosurface; the first scaling factor is determined by dividing the distance of the line segment inside the rectangular boundary of the straight line passing through the first isosurface and parallel to the y-axis by the side length of the rectangle. S3. Multiply the x-coordinate of the second isosurface point along the x-axis by a second scaling factor to modify the distance between vertices in the second isosurface, thereby obtaining a third isosurface; the second scaling factor is determined by dividing the distance of the line segment inside the rectangle boundary of the straight line passing through the second isosurface and parallel to the x-axis by the side length of the rectangle; S4. Determine whether the contour has changed along the z-axis. If the contour section is consistent along the z-axis, generate the target part based on the third isosurface. If the contour section changes uniformly along the z-axis, scale the section according to different z coordinates to generate the target part. If the size and shape of the contour section change along the z-axis, repeat steps S2, S3, and S4 according to different z coordinates until a fourth isosurface is obtained where the size and shape of the section do not change. Use the fourth isosurface to generate the target part.

2. The porous structure modeling method as described in claim 1, characterized in that, The first isosurface is a minimal surface composed of points within the cuboid.

3. The porous structure modeling method as described in claim 2, characterized in that, The formula for modeling the first isosurface is: Where F is the modeling expression for the first isosurface. For a period of time, , , It is a function variable.

4. A porous structure modeling apparatus for implementing the porous structure modeling method of claim 1, characterized in that, include: Model building module; y-axis contour modification module; x-axis contour modification module; Target part generation module.

5. A porous structure modeling device, characterized in that, include: Memory, used to store computer programs; A processor, configured to implement the steps of the porous structure modeling method as described in any one of claims 1 to 3 when executing the computer program.

6. The application of a porous structure modeling method as described in any one of claims 1-3 in biomedical scaffolds.

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