Method for automatically reconstructing complex BIM (Building Information Modeling) in finite element platform

Abstract

The invention discloses a method for automatically reconstructing a complex BIM (Building Information Modeling) in a finite element platform, which relates to the technical field of finite element platforms and comprises the following steps of: acquiring geometric dimension information, spatial position information, physical parameter information and contact information of all final bodies in a model in the BIM platform; disassembling the final body to obtain Boolean operation of forming the final body by the basic body, and obtaining external calculation geometric feature information of the basic body, the process body and the final body; according to Boolean operation and external calculation geometric feature information obtained by disassembling the final body, selecting a corresponding body in the finite element platform to carry out Boolean operation, and reconstructing the final body; and selecting a corresponding final body to establish contact, and endowing the final body with corresponding physical parameter information. According to the method, geometric automatic reconstruction, contact automatic establishment and attribute automatic endowing of the BIM model in a finite element platform are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of finite element platforms, and in particular to a method for automatically reconstructing complex BIM in a finite element platform. Background Art

[0002] The finite element analysis of BIM (Building Information Modeling) is a research hotspot in the engineering industry at the present stage. The most common method is to extract relevant geometric and attribute information in BIM, and then use the parametric modeling function of the finite element platform to regenerate automatically, so as to realize the finite element analysis of BIM. For example, a method for converting a grid structure BIM model and a point cloud model into a finite element model disclosed in Chinese invention patent CN116305418A obtains information such as the center line, nodes, cross-sections, and materials of the grid structure in BIM, and reconstructs in the finite element platform through a command stream to automatically realize the finite element analysis of BIM.

[0003] However, this method is only applicable to the finite element analysis of BIM assembled by simple geometric elements, and is not applicable to BIM with complex geometric elements (obtained by Boolean operations of multiple geometric elements). This is because during the Boolean operation process, the entities participating in the Boolean operation will be deleted first, and then the final body will be regenerated (the regenerated final body will not inherit any information of the original entities participating in the Boolean operation). This process will cause the program to lose the selected target during the reconstruction process and thus cannot achieve automation. Summary of the Invention

[0004] In order to overcome the above defects in the prior art, the present invention provides a method for automatically reconstructing complex BIM in a finite element platform. By obtaining the geometric feature information of the base body, process body, and final body, the object is accurately selected, so as to avoid losing the selected target during the automatic reconstruction process of the program.

[0005] To achieve the above object, the present invention adopts the following technical solutions, including: A method for automatically reconstructing complex BIM in a finite element platform, including the following steps: S1, obtain the geometric dimension information, spatial position information, physical parameter information, and contact information of all final bodies in the model in the BIM platform; The final body refers to a geometric body that is continuous in space and has the same physical parameter information; S2, disassemble the final body to obtain the Boolean operation operations for forming the final body from the base body, record the corresponding Boolean operation operations, and obtain the geometric feature information of the base body, process body, and final body, denoted as external calculation geometric feature information; The base body refers to a geometric body directly generated in the finite element platform by given parameters; The process body refers to the geometric body after performing Boolean operations on the basic body for at least once but before forming the final body; The geometric feature information includes volume, centroid, moment of inertia, and product of inertia; S3. According to the Boolean operation operations and external calculated geometric feature information obtained by disassembling the final body, select the corresponding body in the finite element platform to perform Boolean operation operations and reconstruct the final body; S4. Select the corresponding final body to establish contact according to the external calculated geometric feature information, and assign the corresponding physical parameter information to the final body.

[0006] Preferably, in step S2, the calculation methods of the external calculated geometric feature information of the basic body, process body, and final body are specifically as follows: S21. Set three groups of dividing planes in space. Each dividing plane within each group of dividing planes is parallel and equally spaced, and the different groups of dividing planes are perpendicular to each other; the spacing is a ; S22. Use the three groups of dividing planes to divide the body into multiple units with a volume not greater than a 3 ; among them, the unit with a volume equal to a 3 is called a cube unit, and the unit with a volume less than a 3 is called an equivalent unit; the body refers to the basic body, process body, or final body; S23. Convert the equivalent unit into a polyhedron by equivalent substitution; the equivalent substitution means that the surface that does not coincide with the dividing plane in the equivalent unit is fitted and replaced by a fitting plane; the fitting substitution satisfies that the sum of the squares of the projection distances of all edge intersection points to the fitting plane is the smallest; the edge intersection point refers to the intersection point of the surface that does not coincide with the dividing plane in the equivalent unit and the intersecting edge; the intersecting edge refers to the intersection line formed by the pairwise intersection of all dividing planes; S24. Calculate the volume and centroid of each unit; S25. Denote the volume of each unit as , and the centroid as , then the geometric feature information of the body is as follows: The volume of the body V is: ; The centroid of the body ( X , Y , Z ) is: ; The moments of inertia of the body are respectively: ; The products of inertia of the body are respectively: .

[0007] Preferably, in step S24, the volume of the cubic unit is equal to a 3 , and the centroid is equal to the arithmetic mean of the coordinates of all vertices of the cubic unit; The equivalent unit is disassembled into at least one tetrahedron for calculation; the volume of the equivalent unit is equal to the sum of the volumes of the disassembled tetrahedrons; the centroid of the equivalent unit is the weighted sum of the centroids of each disassembled tetrahedron, and the weight of each tetrahedron centroid is the ratio of the volume of the tetrahedron to the volume of the equivalent unit; the centroid of the tetrahedron is equal to the arithmetic mean of the coordinates of all vertices of the tetrahedron.

[0008] Preferably, step S3 is specifically as follows: S31. According to the disassembly result of step S2, obtain the size information of all basic bodies, the external computational geometric feature information of all basic bodies, the external computational geometric feature information of all process bodies, the external computational geometric feature information of all final bodies, and the Boolean operation information during the final body reconstruction process; S32. Create all basic bodies in the finite element platform according to the size information of the basic bodies; S33. According to the external computational geometric feature information of the basic bodies, process bodies, and final bodies and the Boolean operation information obtained in step S31, perform Boolean operation operations on the corresponding bodies selected through the external computational geometric feature information in the finite element platform to generate all final bodies; Among them, if a final body is directly formed by a basic body, the disassembly process of step S2 is not executed, and the created basic body is directly designated as the final body in step S3.

[0009] Preferably, selecting the corresponding body through the external computational geometric feature information in the finite element platform specifically means: first obtaining the external computational geometric feature information of the body to be selected from step S2, then comparing the external computational geometric feature information with the geometric feature information of all bodies read in the finite element platform, and selecting the body in the finite element platform whose difference between the geometric feature information and the external computational geometric feature information is less than the set error; Selecting the corresponding body through the external computational geometric feature information specifically uses one or more of volume, centroid, moment of inertia, and product of inertia.

[0010] Preferably, in step S4, if the contact between the final bodies is surface-to-surface bonded contact, a shared surface is established at the position where the final bodies are in contact with each other, and the bonded contact is replaced with the shared surface; The shared surface satisfies that, when the finite element mesh is divided, all finite element mesh nodes located on the shared surface are shared mesh nodes of the finite element mesh in the final body on both sides of the shared surface.

[0011] Preferably, the base body includes: a polyhedron, a cylinder, a frustum, a sphere, an ellipsoid, a cone and a body obtained by stretching a base surface; the base surface includes a plane polygon, a circle and an ellipse; the stretching path is a line segment or a polyline.

[0012] Preferably, the model is a model of a composite road foundation; the final body includes a pile body, a post-construction stratum, an embankment and a cushion layer; the contact information includes the friction contact between the pile body and the post-construction stratum, the binding contact between the post-construction stratum and the cushion layer, and the binding contact between the cushion layer and the embankment; the physical parameter information includes the material parameters required for finite element calculation.

[0013] Preferably, in step S2, the pile body and the post-construction stratum are disassembled; The Boolean operation corresponding to the pile body is: Boolean operation of a pile body foundation body 1 minus a pile body foundation body 2 to obtain the pile body, which is a process body; then Boolean operation of a pile body combined with a pile cap to obtain the pile body; The Boolean operation corresponding to the stratum after construction is: subtract n piles from the Boolean operation of a stratum before construction to obtain the stratum after construction; wherein n>1.

[0014] The present invention also provides a computer program product, which includes a computer program / instruction, which, when executed by a processor, implements the method for automatically reconstructing a complex BIM in a finite element platform.

[0015] The advantages of the present invention are: (1) The present invention realizes the automatic reconstruction of geometry, automatic establishment of contacts and automatic assignment of attributes of BIM models in the finite element platform. On this basis, the automatic division and calculation of meshes can be realized with the help of the built-in parametric language related to the finite element platform, thereby truly realizing the finite element calculation of the BIM model and improving the calculation efficiency of the BIM model scheme, which is of great significance to promoting the forward design of BIM.

[0016] (2) During the automatic operation of the finite element platform, the geometric feature information of various external calculations, including volume, center of mass, moment of inertia and product of inertia, is compared with the geometric feature information of the body in the finite element platform to select the corresponding body for operation, effectively ensuring the accuracy of the platform's automatic selection of the body.

[0017] (3) By accurately selecting the final bodies through external computational geometric feature information and performing contact settings and property assignments on them, the problem that the properties of the final bodies (set properties, material properties, etc.) are lost after Boolean operations on the finite element platform, resulting in inability to calculate, is solved.

[0018] (4) By using a combination of various geometric feature attributes of the bodies to uniquely identify the bodies, this method abandons the traditional external identification method of attaching attributes or numbers to the bodies, providing a reference idea for model data transfer and reconstruction between other types of platforms. Description of the Drawings

[0019] Figure 1 It is a flowchart for the automatic reconstruction of BIM in the finite element platform.

[0020] Figure 2 It is a schematic diagram of all the final bodies in this embodiment.

[0021] Figure 3 It is a schematic diagram of the combination of basic bodies into pile bodies in this embodiment.

[0022] Figure 4 It is a schematic diagram of the stratum after the construction of the combination of basic bodies in this embodiment.

[0023] Figure 5 It is a schematic diagram of the generation of equivalent elements.

[0024] The reference numerals are as follows: 1. Edge intersection point; 2. Intersecting edge; 3. Fitting plane; 4. First pile body basic body; 5. Second pile body basic body; 6. Pile shaft; 7. Pile cap; 8. Pile body; 9. Stratum before construction; 10. Group piles; 11. Stratum after construction; 12. Embankment; 13. Cushion. Detailed Implementation Manner

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0026] As Figure 1 shown, a method for automatic reconstruction of a complex BIM in a finite element platform includes the following steps: S1. Obtain the geometric dimension information, spatial position information, physical parameter information, and contact information of all the final bodies in the model in the BIM platform.

[0027] The final body refers to a geometric body that is continuous in space and has the same physical parameter information.

[0028] As Figures 2 - 4 shown, in this embodiment, the model to be reconstructed in the ANSYS platform (finite element analysis and engineering simulation platform) is the model of the road composite foundation, and the final bodies included in this model are: pile body 8, post-construction stratum 11, embankment 12, and cushion 13.

[0029] The contact information includes the frictional contact between the pile body 8 and the post-construction stratum 11, the bonded contact between the post-construction stratum 11 and the cushion 13, and the bonded contact between the cushion 13 and the embankment 12.

[0030] The physical parameter information refers to all material parameters required for finite element calculation. The material parameters required for finite element calculation are related to the calculation purpose. In this embodiment, the road composite foundation needs to obtain the results of settlement and stability through finite element calculation. Therefore, the physical parameter information to be read by the BIM platform includes density, elastic modulus, Poisson's ratio, cohesion, and internal friction angle.

[0031] S2. According to the geometric dimension information of the final bodies, disassemble the final bodies to obtain the Boolean operation operations for forming the final bodies from the basic bodies, record the corresponding Boolean operation operations, and calculate and obtain the geometric feature information of the basic bodies, process bodies, and final bodies, which is denoted as external calculation geometric feature information.

[0032] The basic body refers to the geometric body directly generated in the finite element platform by given parameters. The basic body includes polyhedrons, cylinders, frustums of cones, spheres, ellipsoids, cones, and the bodies obtained by stretching the basic surfaces; the basic surfaces include planar polygons, circles, and ellipses; the stretching path can be a line segment or a polyline. Further, if a basic body obtained by stretching is acquired in the BIM platform and the stretching path is not a polyline, then a polyline is used for approximate substitution.

[0033] The process body refers to the geometric body when the basic body has undergone Boolean operations no less than once but has not yet formed the final body.

[0034] The Boolean operations include Boolean subtraction, Boolean union, and Boolean intersection, which respectively refer to the subtraction, union, and intersection between bodies (basic bodies, process bodies, or final bodies).

[0035] The geometric feature information includes volume, centroid, moment of inertia, and product of inertia.

[0036] As Figure 3 and Figure 4 shown, the pile body 8 and the post-construction stratum 11 can be disassembled.

[0037] The Boolean operation of the pile body 8 is as follows: Boolean subtract a pile body basic body two 5 from a pile body basic body one 4 to obtain a pile shaft 6 (process body); then Boolean unite the pile shaft 6 with a pile cap 7 to obtain the pile body 8. Among them, the pile body basic body one 4 and the pile body basic body two 5 are cylinders with different diameters.

[0038] The Boolean operation of the stratum 11 after construction is as follows: Boolean subtract eight pile bodies 8 from a stratum before construction 9 to obtain the stratum 11 after construction. Among them, the eight pile bodies 8 form a group pile 10.

[0039] Figure 3 and Figure 4 The “+” in it represents Boolean union, and the “−” represents Boolean subtraction.

[0040] In step S2, the calculation methods of the geometric feature information of the basic body, the process body, and the final body are as follows: S21, set three groups of dividing planes in space. Each dividing plane in each group of dividing planes is parallel to each other and arranged at equal intervals, and the different groups of dividing planes are perpendicular to each other; the interval is a .

[0041] S22, use the three groups of dividing planes to divide the body (basic body, process body or final body) into multiple units with a volume not greater than a 3 ; among them, the unit with a volume equal to a 3 is called a cube unit, and the unit with a volume less than a 3 is called an equivalent unit.

[0042] S23, convert the equivalent unit into a polyhedron by equivalent substitution; the equivalent substitution means that the surface that does not coincide with the dividing plane in the equivalent unit is fitted and replaced by a fitting plane 3; the fitting substitution satisfies that the sum of the squares of the projection distances of all the edge intersection points 1 to the fitting plane 3 is the smallest; the edge intersection point 1 refers to the intersection point of the surface that does not coincide with the dividing plane in the equivalent unit and the intersecting edge 2; the intersecting edge 2 refers to the intersection line formed by the pairwise intersection of all the dividing planes.

[0043] As Figure 5 shown, Figure 5 on the left is the equivalent unit (the unit with a volume less than a 3 ), which has a non - coincident curved surface with the dividing plane. This curved surface has four edge intersection points 1 with the intersecting edge 2, Figure 5 and the sum of the squares of the projection distances of the four edge intersection points 1 on the right to the fitting plane 3 is the smallest.

[0044] S24, calculate the volume and centroid of each unit.

[0045] The volume of the cube unit is equal to a 3 , and the centroid is equal to the arithmetic mean of the coordinates of all vertices of the cube unit.

[0046] The equivalent unit is disassembled into at least one tetrahedron (triangular pyramid) for calculation; the volume of the equivalent unit is equal to the sum of the volumes of the disassembled tetrahedrons; the centroid of the equivalent unit is the weighted sum of the centroids of each disassembled tetrahedron, and the weight of each tetrahedron centroid is the ratio of the volume of the tetrahedron to the volume of the equivalent unit; the centroid of the tetrahedron is equal to the arithmetic mean of the coordinates of all vertices of the tetrahedron.

[0047] S25, Denote the volume of each unit as , and the centroid coordinates as , then the geometric characteristic information of the solid (basic solid, process solid or final solid) is as follows: Volume of the solid V is: ; Centroid of the solid( X , Y , Z ) is: ; The moments of inertia of the solid are respectively: ; The products of inertia of the solid are respectively: .

[0048] S3. According to the Boolean operation operations and external calculated geometric characteristic information obtained by disassembling the final solid, reconstruct the final solid in the finite element platform.

[0049] Step S3 is specifically as follows: S31. According to the disassembly results of step S2, obtain the dimension information of all basic solids, the external calculated geometric characteristic information of all basic solids, the external calculated geometric characteristic information of all process solids, the external calculated geometric characteristic information of all final solids, and the Boolean operation operation information during the reconstruction process of the final solid.

[0050] S32. Create all basic solids in the ANSYS platform (finite element platform) according to the dimension information of the basic solids.

[0051] In this embodiment, as Figure 3 shown, the process and APDL code for creating all basic solids (including pile body basic solid 4, pile body basic solid 5, and pile cap 7) involved in creating the pile body 8 in the ANSYS platform are as follows: Let the three-dimensional coordinates of the center point P1 on the top surface of the pile cap 7 in the pile body 8 be (X1, Y1, Z1), and then define the three-dimensional coordinates of point P2 as (X1 + 1, Y1, Z1) and the three-dimensional coordinates of point P3 as (X1, Y1 + 1, Z1); first, use the KWPLAN command to move the origin of the working coordinate system to P1, and make point P2 lie on the X-axis of the working coordinate system, point P3 lie on the Y-axis of the working coordinate system, and the Z-axis direction satisfy the right-hand screw rule; the corresponding APDL code is: KWPLAN, P1, P2, P3.

[0052] The diameter of the pile foundation body 1-4 is D1 and the length is H1; the diameter of the pile foundation body 2-5 is D2 and the length is H1; the length of the pile cap 7 in the X-axis direction is L1, the width in the Y-axis direction is B1, and the height in the Z-axis direction is H2.

[0053] In the above working coordinate system, use the cylinder creation command CYLIND to create the pile foundation body 1-4 with a radius of D1 / 2, the Z-axis coordinate value of the top surface is -H2, and the Z-axis coordinate value of the bottom surface is -H1 - H2; the corresponding APDL code is: CYLIND, D1 / 2, -H2, -H1 - H2.

[0054] Then use the cylinder creation command CYLIND to create the pile foundation body 2-5 with a radius of D / 2, the Z-axis coordinate value of the top surface is -H2, and the Z-axis coordinate value of the bottom surface is -H1 - H2; the corresponding APDL code is: CYLIND, D2 / 2, -H2, -H1 - H2.

[0055] Then use the block creation command BLOCK to create the pile cap 7 with the X-axis range of [-L1 / 2, L1 / 2], the Y-axis range of [-B1 / 2, B1 / 2], and the Z-axis range of [-H2, 0]; the corresponding APDL code is: BLOCK, -L1 / 2, L1 / 2, -B1 / 2, B1 / 2, -H2, 0.

[0056] S33. According to the external computational geometric feature information and Boolean operation information of the base body, process body, and final body obtained in step S31, select the corresponding bodies on the ANSYS platform through the external computational geometric feature information for Boolean operation to generate all final bodies.

[0057] Take Figure 3 as an example, the specific execution process of step S33 is as follows: S331. First, define the external computational geometric feature information of the pile foundation body 1-4, pile foundation body 2-5, pile body 6, and pile cap 7 involved in generating the pile body 8 in the ANSYS platform through APDL code, which is recorded as the external computational geometric feature information set.

[0058] S332. Traverse the geometric feature information of all volumes in the ANSYS platform through the VSUM command in the APDL code. Compare the geometric feature information of the volumes obtained by the VSUM command with the geometric feature information in the external calculation geometric feature information set. Search for and select the volumes with the same external calculation geometric feature information as the pile foundation body 1 - 4, and then search for and select the volumes with the same external calculation geometric feature information as the pile foundation body 2 - 5. Use the volume with the same external calculation geometric feature information as the pile foundation body 1 - 4 to perform a Boolean subtraction on the volume with the same external calculation geometric feature information as the pile foundation body 2 - 5. At this time, the process body pile shaft 6 can be formed in the ANSYS platform.

[0059] S333. Traverse the geometric feature information of all volumes in the ANSYS platform through the VSUM command in the APDL code. Compare the geometric feature information of the volumes obtained by the VSUM command with the geometric feature information in the external calculation geometric feature information set. Search for and select the volumes with the same external calculation geometric feature information as the pile shaft 6, and then search for and select the volumes with the same external calculation geometric feature information as the pile cap 7. Use the volume with the same external calculation geometric feature information as the pile shaft 6 to perform a Boolean union on the volume with the same external calculation geometric feature information as the pile cap 7. At this time, the final body pile 8 can be formed in the ANSYS platform.

[0060] Furthermore, if the final body is directly formed by a single foundation body, there is no need to perform the disassembly step in step S2, and in step S3, directly designate this foundation body as the final body.

[0061] Furthermore, during the reconstruction process of the final body, other final bodies may be added to the Boolean operation process to form this final body.

[0062] For example, after construction, the formation 11 requires the pile 8 for Boolean operation.

[0063] Furthermore, selecting the corresponding volume through the external calculation geometric feature information specifically means: first obtain the external calculation geometric feature information of the volume to be selected from step S2, then compare this external calculation geometric feature information with the geometric feature information of all volumes read in the finite element platform, and select the volume in the finite element platform whose difference between the geometric feature information and this external calculation geometric feature information is less than the set error; the error is a parameter set manually.

[0064] Selecting the corresponding volume through the external calculation geometric feature information specifically can use one or more of volume, centroid, moment of inertia, and product of inertia.

[0065] S4. Select corresponding final bodies based on the external computational geometric feature information of the final bodies, establish contacts for them, and assign corresponding physical parameter information. Further, if the contact between the final bodies is a face-to-face bonded contact, a shared surface is established at the position where the final bodies are in contact through coupled operations, and the bonded contact is replaced with the shared surface.

[0066] The shared surface satisfies that all finite element mesh nodes located on the shared surface during finite element mesh division are shared mesh nodes of the finite element meshes in the final bodies on both sides of the shared surface.

[0067] Such as Figure 2 As shown, the contact type between the embankment 12 and the cushion 13 is usually defined as a face-to-face bonded contact in actual calculations. Considering that too many contacts in the model can easily lead to non-convergence of the calculation, the contact area between the bottom surface of the embankment 12 and the top surface of the cushion 13 can be set as a shared surface. The specific operation process is as follows: Select the embankment 12 and the cushion 13 through the external computational geometric feature information, and set the contact area between the two bodies as a shared surface through the VGLUE command; the selection method here through the external computational geometric feature information is the same as that in S33 through the external computational geometric feature information.

[0068] Because the operation principle of the VGLUE command on the ANSYS platform is the same as that of Boolean operations, the body after the VGLUE command operation needs to be selected again through the external computational geometric feature information and corresponding material properties are assigned.

[0069] In this embodiment, the geometric reconstruction, property assignment, and contact setting of the composite foundation model in the finite element platform are all realized by the command flow operation of APDL. Combined with the element type definition, mesh division, and calculation and solution command flow of ANSYS APDL, the automatic reconstruction and analysis of the composite foundation model in the ANSYS platform can be realized through the command flow. In the actual operation process, only by the secondary development of the BIM platform, when obtaining the model information that needs to participate in the finite element calculation, the corresponding APDL command flow file is generated synchronously, and the ANSYS platform is called in the background to read this command flow file to realize the automated analysis of this type of project.

[0070] Similarly, a finite element platform that can support the whole process of the present invention in terms of secondary development capabilities can also achieve this effect.

[0071] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for automatic reconstruction of complex BIM in a finite element platform, characterized in that It includes the following steps: S1. Obtain the geometric dimension information, spatial position information, physical parameter information, and contact information of all final bodies in the BIM platform; The final body refers to a geometric body that is continuous in space and has the same physical parameter information; S2. Disassemble the final body to obtain the Boolean operation operations for forming the final body from the basic bodies, record the corresponding Boolean operation operations, and obtain the geometric feature information of the basic bodies, process bodies, and final bodies, denoted as external calculation geometric feature information; The basic body refers to a geometric body directly generated in the finite element platform by given parameters; The process body refers to a geometric body that has undergone at least one Boolean operation by the basic body but has not yet formed a final body; The geometric feature information includes volume, centroid, moment of inertia, and product of inertia; S3. According to the Boolean operation operations and external calculation geometric feature information obtained by disassembling the final body, select the corresponding bodies in the finite element platform for Boolean operation operations to reconstruct the final body; S4. Establish contacts for the corresponding final bodies according to the external calculation geometric feature information and assign the corresponding physical parameter information to the final bodies.

2. The method for automatic reconstruction of a complex BIM in a finite element platform according to claim 1, characterized in that, In step S2, for the external calculation geometric feature information of the basic bodies, process bodies, and final bodies, the calculation method is as follows: S21, Set three groups of dividing surfaces in space. Each dividing surface within each group of dividing surfaces is parallel to each other and arranged at equal intervals, and the dividing surfaces between different groups are perpendicular to each other; the interval is a ; S22, the body is divided into multiple units with a volume not greater than a 3 by using three sets of dividing planes; among them, the units with a volume equal to a 3 are called cube units, and the units with a volume less than a 3 are called equivalent units; the body refers to the basic body, the process body or the final body; S23. Replace the equivalent element with an equivalent substitution to convert it into a polyhedron; the equivalent substitution means that the faces of the equivalent element that do not coincide with the segmentation surface are fitted and replaced by a fitting plane (3); the fitting substitution satisfies that the sum of the squares of the projection distances of all edge intersection points (1) to the fitting plane (3) is the smallest; the edge intersection point (1) refers to the intersection point of the face of the equivalent element that does not coincide with the segmentation surface and the intersecting edge (2); the intersecting edge (2) refers to the intersection line formed by the pairwise intersection of all segmentation surfaces; S24. Calculate the volume and centroid of each element; S25, denote the volume of each unit as , and the centroid as , then the geometric feature information of the volume is as follows: Volume of the body V is as follows: ； The centroid of the body ( X , Y , Z ) is: ； The moment of inertia of the body is respectively: ； The product of inertia of the body is respectively: 。 3. A method for automatic reconstruction of a complex BIM in a finite element platform according to claim 2, characterized in that, In step S24, the volume of the cube unit is equal to a 3 , and the centroid is equal to the arithmetic mean of the coordinates of all vertices of the cube unit; Disassemble the equivalent element into at least one tetrahedron for calculation; the volume of the equivalent element is equal to the sum of the volumes of the disassembled tetrahedrons; The centroid of the equivalent element is the weighted sum of the centroids of each tetrahedron after disassembly, and the weight of each tetrahedron centroid is the ratio of the volume of the tetrahedron to the volume of the equivalent element; the centroid of the tetrahedron is equal to the arithmetic mean of the coordinates of all vertices of the tetrahedron.

4. A method for automatic reconstruction of a complex BIM in a finite element platform according to claim 1, characterized in that, Step S3 is specifically as follows: S31. According to the disassembly results of step S2, obtain the dimension information of all basic bodies, the external calculation geometric feature information of all basic bodies, the external calculation geometric feature information of all process bodies, the external calculation geometric feature information of all final bodies, and the Boolean operation operation information during the reconstruction process of the final body; S32. Create all basic bodies in the finite element platform according to the dimension information of the basic bodies; S33. According to the external calculation geometric feature information of the basic bodies, process bodies, and final bodies and the Boolean operation operation information obtained in step S31, select the corresponding bodies in the finite element platform for Boolean operation operations through the external calculation geometric feature information to generate all final bodies; Among them, if the final body is directly formed by one basic body, the disassembly process of step S2 is not executed, and in step S3, the created basic body is directly designated as the final body.

5. A method for automatic reconstruction of a complex BIM in a finite element platform according to claim 1 or 4, characterized in that, In the finite element platform, the corresponding volume is selected through external computational geometric feature information, specifically: first, obtain the external computational geometric feature information of the volume to be selected from step S2, then compare this external computational geometric feature information with the geometric feature information of all volumes read in the finite element platform, and select the volume in the finite element platform whose difference between the geometric feature information and the external computational geometric feature information is less than the set error; Selecting the corresponding volume through external computational geometric feature information specifically uses one or more of volume, centroid, moment of inertia, and product of inertia.

6. A method for automatic reconstruction of a complex BIM in a finite element platform according to claim 1, characterized in that In step S4, if the contact between the final volumes is surface-to-surface bonded contact, a shared surface is established at the position where the final volumes are in contact with each other, and the bonded contact is replaced with the shared surface; The shared surface satisfies that all finite element mesh nodes located on the shared surface during finite element mesh division are shared mesh nodes of the finite element meshes in the final volumes on both sides of the shared surface.

7. A method for automatic reconstruction of a complex BIM in a finite element platform according to claim 1, characterized in that, The basic volumes include: polyhedron, cylinder, frustum of a cone, sphere, ellipsoid, cone, and the volume obtained by stretching the basic surface; the basic surface includes plane polygon, circle, and ellipse; the stretching path is a line segment or a polyline.

8. A method for automatic reconstruction of a complex BIM in a finite element platform according to claim 1, characterized in that The model is a model of a road composite foundation; the final volumes include pile bodies (8), post-construction strata (11), embankment (12), and cushion (13); the contact information includes frictional contact between the pile bodies (8) and the post-construction strata (11), bonded contact between the post-construction strata (11) and the cushion (13), and bonded contact between the cushion (13) and the embankment (12); the physical parameter information includes the material parameters required for finite element calculation.

9. A method for automatic reconstruction of a complex BIM in a finite element platform according to claim 8, characterized in that In step S2, the pile bodies (8) and the post-construction strata (11) are disassembled; The Boolean operation corresponding to the pile body (8) is: Boolean subtract a pile body basic volume one (4) from a pile body basic volume two (5) to obtain a pile shaft (6), and the pile shaft (6) is a process volume; then Boolean union a pile shaft (6) and a pile cap (7) to obtain a pile body (8); The Boolean operation corresponding to the post-construction strata (11) is: Boolean subtract n pile bodies (8) from a pre-construction stratum (9) to obtain the post-construction strata (11); where n > 1.

10. A computer program product, characterized in that, It includes a computer program / instructions, and when the computer program / instructions are executed by a processor, it implements the method for automatic reconstruction of a complex BIM in a finite element platform according to any one of claims 1 to 8.

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