Mesh model generation system, mesh model generation method

Abstract

Based on BIM data of building structures constructed using concrete, a 3D mesh model is generated that provides high analytical accuracy. [Solution] The mesh model generation system 1 includes: a structural member data adjustment unit 12 that determines overlaps between structural member data, assumes that the overlapping portion is a joint between structural members, generates joint data corresponding to the joint, and deletes the overlapping portion from each of the structural member data; a structural member mesh division unit 23 that generates a structural member mesh model by meshing each of the structural member data to be divided, which are generated based on each of the structural member data; a joint mesh division unit 24 that generates a joint mesh model by meshing each of the joint data to be divided, which are generated based on each of the joint data; and a building structure mesh model generation unit 25 that generates a building structure mesh model by integrating the structural member mesh model and the joint mesh model.

Description

Technical Field

[0001] The present invention relates to a mesh model generation system and a mesh model generation method.

Background Art

[0002] When grasping the behavior of a building structure during an earthquake, finite element method analysis may be used. Generally, finite element method analysis is performed by numerically analyzing a three-dimensional mesh model generated as an aggregate of mesh elements of a simple shape by mesh-dividing data of a building structure expressed as a three-dimensional shape. In finite element method analysis, numerical analysis is performed on a mesh model that faithfully reproduces the shape of the building structure to a certain extent, so basically, high-precision analysis results can be obtained.

[0003] Regarding this, Patent Document 1 discloses a method for creating a finite element model that can improve the efficiency of work when creating a FEM model from BIM data. The method includes a first step of determining whether or not a plurality of members in geometry data generated based on analysis model data are in a connected state based on the distance between members and the cross-sectional dimensions of the members in the BIM data, and moving the members constituting the geometry data and updating the geometry data when it is determined that they are in a connected state; and a second step of determining whether or not a member in the geometry data can be regarded as being on a predetermined reference line based on the position of the reference line in the BIM data, the position of the member, and the cross-sectional dimensions, and moving the members constituting the geometry data and updating the geometry data when it is determined that the member can be regarded as being on the reference line.

[0004] In finite element analysis as described above, in principle, the smaller the mesh element size, the more accurate the analysis results can be obtained. However, when the target of finite element analysis is a building structure, especially one constructed using concrete, if the mesh is divided to a small size to generate a mesh model and then the finite element analysis is performed, the failure may be concentrated at a minute point due to the nonlinear relationship between stress and deformation in concrete, which may prevent the accurate representation of the concrete's properties. Furthermore, generally, dividing the mesh to a small size can significantly increase the time required for finite element analysis. Therefore, when generating a mesh model for a building structure constructed using concrete, it is desirable to use a moderately large mesh element size.

[0005] Incidentally, in the mesh division described above, the mesh is basically divided so that the mesh elements have the shape of a hexahedron (cuboid or cube), and a 3D mesh model is generated. Here, in building structures, for example, each structural member such as columns, beams, walls, and floors has a shape close to a cuboid, so it seems that the mesh elements tend to become hexahedrons during mesh division. However, if the mesh elements are made to a moderately large size as described above, for example, at joints where structural members are joined to each other, in order to follow the differences in shape between the structural members being joined, a large number of mesh elements with the shape of a tetrahedron (triangular pyramid) are generated in addition to the hexahedron mesh elements in a wide area around the joint, and there is a possibility that the mesh will be divided in a way that mixes hexahedron mesh elements (hereinafter referred to as hexahedron elements) and tetrahedron mesh elements (hereinafter referred to as tetrahedron elements).

[0006] However, hexahedral elements and tetrahedral elements have different properties. In particular, in finite element analysis targeting concrete, if tetrahedral elements are used, the physical properties of the concrete may not be accurately represented. For this reason, even if finite element analysis is performed using a mesh model containing many tetrahedral elements generated as described above, the desired accuracy of the analysis results may not be obtained. There is a need to generate a 3D mesh model that can achieve high analytical accuracy based on BIM data of building structures constructed using concrete. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2023-25814 [Overview of the project] [Problems that the invention aims to solve]

[0008] The problem that this invention aims to solve is to provide a mesh model generation system and a mesh model generation method that can generate a 3D mesh model with high analytical accuracy based on BIM data of a building structure constructed using concrete. [Means for solving the problem]

[0009] To solve the above problems, the present invention employs the following means. That is, the present invention provides a mesh model generation system that generates a three-dimensional mesh model based on BIM data of a building structure constructed using concrete, wherein the BIM data includes structural member data corresponding to each of a plurality of structural members constituting the building structure, and the system determines overlaps between the structural member data, assumes that the overlapping portion is a joint between the structural members, generates joint data corresponding to the joint, and deletes the overlapping portion from each of the structural member data; a structural member mesh division unit that generates a structural member mesh model by meshing each of the structural member data to be divided, which is generated based on each of the structural member data; a joint mesh division unit that generates a joint mesh model by meshing each of the joint data to be divided, which is generated based on each of the joint data; and a building structure mesh model generation unit that generates the mesh model of the building structure by accumulating the structural member mesh model and the joint mesh model. With the configuration described above, BIM data for a building structure constructed using concrete includes structural member data corresponding to each of the multiple structural members that make up the building structure, such as walls and floors. If there are overlapping parts in the structural member data, these are considered to be joints where the structural members corresponding to those structural member data are joined together. For example, if walls and floors are provided as structural members, and the structural member data corresponding to them overlaps by intersecting each other, if the overlapping part of the structural member data is considered a joint, and the parts of the structural member data other than the joint are considered to be the original structural members such as walls and floors, then the interface between the part considered to be a joint and the part considered to be the original structural member is basically a single plane, and as a result, the part of the structural member data that can be considered to be the original structural member is considered to be a rectangular prism or a shape close to a rectangular prism. Based on this idea, the structural member data adjustment unit determines overlaps between structural member data, assumes that the overlapping portion is a joint between structural members, generates joint data corresponding to that joint, and deletes the overlapping portion corresponding to the joint data from each of the structural member data. In this way, a structural member mesh model is generated by meshing the structural member data to be divided, which is generated based on the structural member data from which the overlapping portion corresponding to the joint data has been deleted. The resulting structural member data from which the overlapping portion corresponding to the joint data has been deleted, which is the basis for generating this structural member mesh model, is rectangular parallelepiped as described above. Therefore, the structural member mesh model is basically meshed using only hexahedral elements, and tetrahedral elements are unlikely to be mixed in the structural member mesh model. In this way, the number of tetrahedral elements is reduced in the structural member mesh model, which is the main object of behavior observation when performing finite element method analysis, so that the physical properties and characteristics of concrete are appropriately reflected in the analysis results. On the other hand, with respect to joints, a joint mesh model is generated by meshing the joint data to be divided, which is generated based on the joint data. One method for generating a joint mesh model is to first mesh each of the structural member data to be divided to generate a structural member mesh model, and then mesh the joint data to be divided collectively in three dimensions so that the structural member mesh model generated by meshing the structural member data that comes into contact with the joint data to be divided shares the nodes facing the joint data in question. Here, since each of the structural member data to be divided is meshed individually, the number of nodes and the size of the mesh elements may not be uniform and may be inconsistent in the multiple structural member mesh models generated for each of the structural member data that comes into contact with a given joint data. For this reason, when the joint mesh model is generated, the mesh is divided in a way that connects the inconsistent mesh elements, and as a result, tetrahedral elements may be mixed in the joint mesh model. However, joints can be considered rigid bodies (less prone to failure and therefore not important from a seismic analysis perspective) when performing finite element analysis, and even if tetrahedral elements are mixed in such parts, the impact on the analysis accuracy will be limited. In this way, the number of tetrahedral elements in the structural member mesh model is reduced, and tetrahedral elements are concentrated in joints that are not important for seismic analysis. As a result, the analysis accuracy of the entire mesh model of the building structure is improved. Another method for generating a joint mesh model is to mesh the joint data to be divided independently of the structural member mesh model, without sharing nodes with the contacting structural member mesh model, thereby generating a joint mesh model. The structural member mesh model and the joint mesh model can then be associated by setting multi-point constraints at the nodes located at the interface between the structural member mesh model and the joint mesh model. If the structural member data is rectangular, then the overlapping parts should also be basically rectangular, so the joint data and the joint data to be divided should also be rectangular. Therefore, the joint mesh model, like the structural member mesh model, will basically be meshed using only hexahedral elements, and tetrahedral elements will be less likely to be mixed in the joint mesh model as well as the structural member mesh model. As a result, the overall analysis accuracy of the mesh model of the building structure is improved. In this way, it becomes possible to generate a 3D mesh model with high analytical accuracy based on BIM data of building structures constructed using concrete.

[0010] In one embodiment of the present invention, when the structural member is a floor or a wall, the structural member data representation modification unit generates the structural member data to be divided so as to represent the structural member by the shape of the main surface extending in a plane perpendicular to the thickness direction of the floor or the wall, the thickness, the in-plane direction in which the main surface extends, and the thickness direction, wherein the in-plane direction includes a first in-plane direction and a second in-plane direction, which are directions along each of the mutually orthogonal edge sides of the main surface, and the structural member mesh division unit, when the structural member is a floor or a wall, divides the main surface into a mesh in two dimensions in the first in-plane direction and the second in-plane direction, reflects the mesh division state of the main surface at all positions in the thickness direction, and then divides the structural member data to be divided into three dimensions by meshing in one dimension in the thickness direction. With the configuration described above, if the structural member is a floor or a wall, the structural member data to be divided is represented by the shape of the main surface extending in a plane perpendicular to the thickness direction of the floor or wall, its thickness, the in-plane direction in which the main surface extends, and the thickness direction. For such structural member data to be divided, the structural member mesh division unit first divides the main surface into two dimensions by a first in-plane direction and a second in-plane direction, which are directions along each of the mutually orthogonal edges of the main surface. Since the main surfaces of floors and walls are basically formed in a rectangular shape, by doing so, the main surface can be meshed using basically only quadrilaterals. Furthermore, the structural member mesh division section reflects the mesh division state of the main surface at all positions in the thickness direction. As a result, at any position in the thickness direction of the structural member, the mesh division state is the same as that of the main surface. Therefore, by performing mesh division in one dimension in the thickness direction in this state, the structural member data to be divided is meshed in three dimensions. As already explained, the main surface is basically meshed only with quadrilaterals, so as a result of three-dimensional mesh division, a structural member mesh model is generated with hexahedral elements as the main mesh elements. In particular, floors and walls may have rectangular openings, such as windows and inspection hatches, that penetrate through the thickness. Such openings are located at the same position in the in-plane direction at all locations in the thickness direction. Therefore, when meshing the main surface in two dimensions, the shape of the openings can be taken into consideration, for example, by aligning the mesh division lines with the edges of the openings, allowing the main surface to be meshed mainly with rectangles. Then, by reflecting the mesh division state of the main surface at all locations in the thickness direction and meshing in one dimension in the thickness direction, the structural member data to be divided becomes a three-dimensional mesh mainly consisting of hexahedral elements. In this way, even when floors and walls have rectangular openings, the structural member data to be divided can be meshed in three dimensions using mainly hexahedral elements.

[0011] In another embodiment of the present invention, the joint mesh division unit divides the joint data to be divided into a mesh in three dimensions collectively such that the structural member mesh model generated by meshing the structural member data to be divided that is in contact with the joint data to be divided shares nodes facing the joint data to be divided. With the above configuration, the target joint data is meshed in three dimensions collectively so that the nodes facing the target joint data are shared between the structural member mesh model, which is generated by meshing the structural member data that comes into contact with the target joint data. As a result, nodes are shared between the structural member mesh model and the joint mesh model that are in contact with each other and adjacent to each other. Consequently, when the structural member mesh model and the joint mesh model are combined to generate a mesh model of the building structure, there is node consistency between the structural member mesh model and the joint mesh model. In this way, a consistent and appropriate mesh model of the building structure can be generated.

[0012] In another embodiment of the present invention, the joint data representation modification unit generates the division target joint data such that the joint is represented by any one surface of the joint, the shape of the main surface, the length in an orthogonal direction perpendicular to the main surface, the in-plane direction in which the main surface extends, and the orthogonal direction, wherein the in-plane direction includes a first in-plane direction and a second in-plane direction, which are directions along each of the mutually orthogonal edge sides of the main surface, the joint mesh division unit divides the main surface into a mesh in two dimensions in the first in-plane direction and the second in-plane direction, reflects the mesh division state of the main surface at all positions in the orthogonal direction, and then divides the division target joint data into a mesh in one dimension in the orthogonal direction, thereby dividing the division target joint data into a mesh in three dimensions, and the building structure mesh model generation unit sets multipoint constraint conditions at nodes located at the interface between the structural member mesh model and the joint mesh model that are in contact with each other. With the above configuration, the data for the joint to be divided is represented by the shape of one of the surfaces of the joint, the length in the orthogonal direction perpendicular to the main surface, the in-plane direction in which the main surface extends, and the orthogonal direction. For such data for the joint to be divided, the joint mesh division unit first divides the main surface into two dimensions using the first in-plane direction and the second in-plane direction, which are directions along each of the mutually orthogonal edges of the main surface. Since the main surface is basically formed in a rectangular shape, by doing so, the main surface can be meshed using basically only quadrilaterals. Furthermore, the joint mesh division section reflects the mesh division state of the main surface at all positions in the orthogonal direction. As a result, at any position in the orthogonal direction of the joint, the mesh division state is the same as that of the main surface. Therefore, by performing mesh division in one dimension in the orthogonal direction in this state, the joint data to be divided is meshed in three dimensions. As already explained, the main surface is basically meshed only with quadrilaterals, so as a result of mesh division in three dimensions, a joint mesh model is generated with hexahedral elements as the main mesh elements. However, as described above, if the data of the joint to be divided is meshed individually, independently of the structural member data that comes into contact with the data of the joint to be divided, nodes will not be shared between the structural member mesh model and the joint mesh model. As a result, when the structural member mesh model and the joint mesh model are combined to generate the mesh model of the building structure, there will be no consistency in the nodes between the structural member mesh model and the joint mesh model. In contrast to this, in the above configuration, multi-point constraint conditions are set at the nodes located at the interface between the structural member mesh model and the joint mesh model that come into contact with each other. As a result, when finite element analysis is performed on the mesh model of the building structure, the nodes located within the interface of both the structural member mesh model and the joint mesh model are constrained to a plane and deformed, so that the behavior is appropriately transmitted between the structural member mesh model and the joint mesh model. In this way, a mesh model of the building structure can be generated that allows for appropriate finite element method analysis.

[0013] In another embodiment of the present invention, if the structural member is a floor or a wall and the structural member data are in contact with each other without overlapping, the structural member data is stretched in a direction perpendicular to the thickness direction of the floor or wall to generate overlapping portions between the structural member data, the overlapping portions are considered to be the joints between the structural members, the joint data corresponding to the joints is generated, and the overlapping portions are deleted from each of the structural member data. With the configuration described above, joint data can be generated appropriately.

[0014] Furthermore, the present invention provides a mesh model generation method for generating a three-dimensional mesh model based on BIM data of a building structure constructed using concrete, wherein the BIM data includes structural member data corresponding to each of a plurality of structural members constituting the building structure, the method includes a structural member data adjustment step which determines the overlap between the structural member data, assumes that the overlapping portion is a joint between the structural members, generates joint data corresponding to the joint, and deletes the overlapping portion from each of the structural member data; a structural member mesh division step which generates a structural member mesh model by meshing each of the structural member data to be divided, which is generated based on each of the structural member data; a joint mesh division step which generates a joint mesh model by meshing each of the joint data to be divided, which is generated based on each of the joint data; and a building structure mesh model generation step which generates the mesh model of the building structure by accumulating the structural member mesh model and the joint mesh model. With the configuration described above, as already explained regarding the mesh model generation system, it becomes possible to generate a 3D mesh model with high analytical accuracy based on BIM data of building structures constructed using concrete.

[0015] Furthermore, the present invention provides a mesh model generation system that generates a three-dimensional mesh model based on BIM data of a building structure constructed using concrete, wherein the BIM data includes structural member data corresponding to each of a plurality of structural members constituting the building structure, and the system comprises: a structural member data adjustment unit that determines overlaps between the structural member data and adjusts the system so that there are no overlaps between the structural member data by deleting the overlapping portion from one of the structural member data having an overlapping portion; a structural member mesh division unit that generates a structural member mesh model by meshing each of the structural member data to be divided, which are generated based on each of the structural member data; and a building structure mesh model generation unit that generates the mesh model of the building structure by aggregating the structural member mesh models. With the configuration described above, BIM data for a building structure constructed using concrete includes structural member data corresponding to each of the multiple structural members that make up the building structure, such as walls and floors. In a building structure, structural members are basically formed in the shape of a rectangular prism, such as walls and floors, and when there are overlapping parts in the structural member data, the boundary between the overlapping part and the non-overlapping part is planar. Therefore, by determining the overlap between structural member data and removing the overlapping part from one of the structural member data that has an overlapping part, the overlap between the structural member data is eliminated, and as a result, each structural member data is adjusted to become a rectangular prism or a shape close to a rectangular prism. A structural member mesh model is generated by meshing the structural member data to be divided, which is generated based on the structural member data that has become rectangular in shape in this way. The resulting structural member data, which is adjusted to eliminate overlaps and serves as the basis for generating this structural member mesh model, is rectangular in shape as described above. Therefore, the structural member mesh model is basically meshed using only hexahedral elements, and tetrahedral elements are unlikely to be mixed into the structural member mesh model. In this way, the number of tetrahedral elements is reduced in the structural member mesh model, so the physical properties and characteristics of the concrete are appropriately reflected in the analysis results. Furthermore, in the configuration described above, the mesh model of the building structure is generated by accumulating structural member mesh models that are basically composed only of hexahedral elements. Therefore, the mesh model of the building structure is also basically composed only of hexahedral elements. In this way, the number of tetrahedral elements included in the mesh model of the building structure is reduced, and as a result, the accuracy of the analysis when finite element method analysis is performed is improved. In this way, it becomes possible to generate a 3D mesh model with high analytical accuracy based on BIM data of building structures constructed using concrete.

[0016] In another embodiment of the present invention, the building structure mesh model generation unit sets multipoint constraint conditions at nodes located at the interface between the structural member mesh models that are in contact with each other. When there are structural member data to be divided that are in contact with each other, if each of them is meshed independently as described above, nodes will not be shared between the structural member mesh models. As a result, when the structural member mesh models are combined to generate a mesh model of the building structure, there will be no consistency in the nodes between the structural member mesh models. In contrast, in the configuration described above, multi-point constraint conditions are set at the nodes located at the interface of the structural member mesh models that are in contact with each other. As a result, when finite element analysis is performed on the mesh model of the building structure, the nodes located within the interface of both structural member mesh models are constrained to the plane and deformed, so that the behavior is appropriately transmitted between the structural member mesh models. In this way, a mesh model of the building structure can be generated that allows for appropriate finite element method analysis.

[0017] Furthermore, the present invention provides a mesh model generation method for generating a three-dimensional mesh model based on BIM data of a building structure constructed using concrete, wherein the BIM data includes structural member data corresponding to each of a plurality of structural members constituting the building structure, and the method includes a structural member data adjustment step of determining overlaps between the structural member data and adjusting the data so that there are no overlaps between the structural member data by deleting the overlapping portion from one of the structural member data having an overlapping portion; a structural member mesh division step of generating a structural member mesh model by meshing each of the structural member data to be divided, which are generated based on each of the structural member data; and a building structure mesh model generation step of generating the mesh model of the building structure by aggregating the structural member mesh models. According to the above configuration, as already described with respect to the mesh model generation system, it becomes possible to generate a three-dimensional mesh model with high analysis accuracy based on the BIM data of a building structure constructed using concrete.

Effect of the Invention

[0018] According to the present invention, it is possible to provide a mesh model generation system and a mesh model generation method capable of generating a three-dimensional mesh model with high analysis accuracy based on the BIM data of a building structure constructed using concrete.

Brief Description of the Drawings

[0019] [Figure 1] It is an explanatory diagram of BIM data. [Figure 2] It is an explanatory diagram of a mesh model of a building structure, which is the result of batch mesh division for all structural member data in BIM data. [Figure 3] It is a block diagram of a mesh model generation system according to the first embodiment of the present invention. [Figure 4] It is an explanatory diagram showing an example of structural member data in BIM data. [Figure 5] It is a table showing the reinforcement state for the structural member data shown in FIG. 4. [Figure 6] It is an explanatory diagram showing a state in which a steel bar layer based on the reinforcement shown in FIG. 5 is added to the structural member data shown in FIG. 4. [Figure 7] It is an explanatory diagram showing a state in which structural member data overlaps. [Figure 8] It is an explanatory diagram showing a state in which joint data is generated from the state shown in FIG. 7. [Figure 9] It is an explanatory diagram showing a state in which structural member data is in contact without overlapping. [Figure 10] It is an explanatory diagram of IFC data. [Figure 11] It is a perspective view of the structural member data to be divided. [Figure 12] Figure 11 is a perspective view showing the main surface after being meshed in two dimensions in the first and second in-plane directions. [Figure 13] Figure 12 is a perspective view showing the mesh division state of the main surface reflected at all positions in the orthogonal direction. [Figure 14] This is an explanatory diagram showing the state after generating a structural member mesh model by meshing in one dimension in the orthogonal direction, relative to Figure 13. [Figure 15] This is a perspective view showing the initial two-dimensional mesh division of a surface that extends in the thickness direction, distinct from the main surface. [Figure 16] This is an explanatory diagram regarding the case where the data of the joint to be divided is meshed using the first division method. [Figure 17] This is an explanatory diagram regarding the case where the joint data to be divided is meshed using the second division method. [Figure 18] This is an explanatory diagram regarding multi-point constraint conditions. [Figure 19] This is a flowchart of a mesh model generation method using the mesh model generation system according to the first embodiment described above. [Figure 20] This is a perspective view showing the state in which the main surface of structural member data for columns and beams, which are to be divided, has been meshed in two dimensions in the first and second in-plane directions. [Figure 21] Figure 20 is an explanatory diagram showing the state in which the mesh division state of the main surface is reflected at all positions in the longitudinal direction, and then the mesh is divided in one dimension in the longitudinal direction to generate a structural member mesh model. [Figure 22] This is a block diagram of a mesh model generation system according to a second embodiment of the present invention. [Figure 23] This is an explanatory diagram showing the state after removing the overlapping portions between structural member data from the state shown in Figure 7. [Figure 24] This is an explanatory diagram showing the state after mesh division has been performed on the structural member data to be divided, which was generated from the state shown in Figure 23. [Figure 25]This is a flowchart of the mesh model generation method using the mesh model generation system according to the second embodiment described above. [Modes for carrying out the invention]

[0020] Embodiments of the present invention will be described in detail below with reference to the drawings. (First Embodiment) Figure 1 is an explanatory diagram of BIM data. When designing a building structure, a three-dimensional model is generated that reproduces the actual building structure, as shown in Figure 1 as BIM (Building Information Modeling) data 100. Such BIM data 100 includes structural member data 101 corresponding to each of the multiple structural members that make up the building structure. If the structural members are, for example, walls or floors, the BIM data 100 includes wall data 102 and floor data 103 as structural member data 101.

[0021] Figure 2 is an explanatory diagram of the mesh model of a building structure, obtained by performing a batch mesh division on all structural member data in the BIM data. To perform finite element analysis on a building structure, the BIM data 100 described above is meshed to generate a mesh model 150 of the building structure, which is divided into multiple mesh elements M. In the meshing process, hexahedral mesh elements (hereinafter referred to as hexahedral elements M6) and tetrahedral mesh elements (hereinafter referred to as tetrahedral elements M4) are mixed. For example, in the mesh model 150 of the building structure shown in Figure 2, tetrahedral elements M4 are used extensively around parts with complex shapes, such as openings 102h corresponding to windows, doors, inspection hatches, etc., in walls and floors, and joints J between walls and floors, so that the meshing follows the complex shapes. However, in finite element analysis, especially for concrete, the use of tetrahedral elements M4 may result in inaccurate representation of the concrete's properties. The mesh model generation system of this embodiment generates the mesh model 150 of the building structure in such a way that the number of generated tetrahedral elements M4 is reduced.

[0022] Figure 3 is a block diagram of the mesh model generation system according to this embodiment. The mesh model generation system 1 of this embodiment generates a three-dimensional mesh model 150 of a building structure based on BIM data 100 of a building structure constructed using concrete. The mesh model generation system 1 of this embodiment basically targets reinforced concrete building structures, but the building structure may also be made of steel-reinforced concrete. The mesh model generation system 1 operates on an information processing terminal such as a personal computer or server. Functionally, the mesh model generation system 1 includes a reinforcement layer generation unit 11, a structural member data adjustment unit 12, an IFC data output unit 13, a structural member data representation modification unit 21, a joint data representation modification unit 22, a structural member mesh division unit 23, a joint mesh division unit 24, and a building structure mesh model generation unit 25.

[0023] The BIM data 100 includes reinforcement data relating to the reinforcing bars provided inside the structural members. The reinforcement layer generation unit 11 generates a reinforcement layer having a thickness corresponding to the reinforcing bars included in the reinforcement data from the reinforcement data. Figure 4 is an explanatory diagram showing an example of structural member data in BIM data. Figure 5 is a table showing the reinforcement status for the structural member data shown in Figure 4. In Figure 4, structural member data 101 is shown, consisting of one wall data 102 and one floor data 103. Each of these structural member data 101 is assigned a code (identification number) as shown in Figure 5, and the type of reinforcement arrangement is defined for each code. The reinforcement layer generation unit 11 generates a reinforcement layer 110 for each of the structural member data 101 based on the reinforcement data defined for that structural member data 101.

[0024] Figure 6 is an explanatory diagram showing the structural member data shown in Figure 4 with the addition of a reinforcement layer based on the reinforcement arrangement shown in Figure 5. For example, in floor data 103, indicated by the symbol "S100" in Figure 4, multiple reinforcing bars with a diameter of approximately 32 mm are arranged in a row at intervals of 100 mm in the depth direction DD of the floor. The reinforcing bar layer generation unit 11 determines the thickness of the reinforcing bar layer 110 so that it corresponds to the total amount of reinforcing bars provided in this manner. In floor data 103, indicated by the symbol "S100", the "number of reinforcing bar layers" is 1, so in Figure 6, two reinforcing bar layers 110, generated in the manner described above, are provided, one on the upper side and one on the lower side of the floor data 103. The reinforcement layer generation unit 11 generates a reinforcement layer 110 for the wall data 102 in the same manner.

[0025] The data for the reinforcement layer 110 generated in this way is output together with the structural member data 101 in the IFC data 120, which will be explained later. The data for the reinforcement layer 110 is also output to the mesh model 150 of the building structure, which is the final output of the mesh model generation system 1. When the analysis software that performs finite element method analysis with the mesh model 150 of the building structure as input reads the data for the reinforcement layer 110, it performs the finite element method analysis assuming that the reinforcement layer 110 exists in the structural member defined in the mesh model 150 of the building structure where the reinforcement layer 110 is provided.

[0026] The structural member data adjustment unit 12 adjusts the shape of the structural member data 101 and generates joint data. Figure 7 is an explanatory diagram showing the state in which structural member data overlaps. Figures 7, and Figures 8 and 9 which will be used in later explanations, are two-dimensional drawings of walls and floors viewed from the side (the width direction of the walls and floors), but the structural member data adjustment unit 12 actually performs the following processing as a three-dimensional calculation. In BIM data 100, structural member data 101 may be provided in an overlapping manner. In the example in Figure 7, two floor data 103 are provided adjacent to each other in the horizontal direction. The ends 103a of these two floor data 103 are in contact with each other. One wall data 102 is provided vertically, penetrating the floor data 103 so as to overlap with the portion where the ends 103a are in contact. For example, the structural member data adjustment unit 12 determines the overlap between structural member data 101. As a result, in the case of Figure 7, it is determined that there is an OR where multiple structural member data 101 overlap.

[0027] Figure 8 is an explanatory diagram showing the state in which joint data has been generated from the state shown in Figure 7. In such cases, the structural member data adjustment unit 12 assumes that the overlapping portion OR is a joint J between structural members, and generates joint data 105 corresponding to the joint J as part of the data included in the BIM data 100. The structural member data adjustment unit 12 then deletes the overlapping OR from each of the structural member data 101 that has been determined to have an overlapping OR, which corresponds to the generated joint data 105. In Figure 8, the left floor data 103 shown in Figure 7 has its right end 103a cut, and the left floor data 103 has been adjusted so that its end face abuts against the left surface of the joint data 105. Similarly, the right floor data 103 shown in Figure 7 has its left end 103a cut, and the right floor data 103 has been adjusted so that its end face abuts against the right surface of the joint data 105. Furthermore, the wall data 102 is divided into two parts vertically. Then, the upper wall data 102 is adjusted so that the end face of the lower end 102a of the upper wall data 102 abuts against the upper surface of the joint data 105. Furthermore, the lower wall data 102 is adjusted so that the end face of the upper end 102a of the lower wall data 102 abuts against the lower surface of the joint data 105. As a result, the shapes of each structural member data 101 and joint data 105 are adjusted so that there are no overlapping OR portions between each structural member data 101 and the joint data 105, and that they are in contact with each other.

[0028] Figure 9 is an explanatory diagram showing a state in which structural member data are in contact with each other without overlapping. In Figure 9, two floor data 103 are provided adjacent to each other in the horizontal direction. The ends 103a of these two floor data 103 are in contact with each other. Two wall data 102 are provided so as to be vertically divided by the floor data 103. The lower end face of the upper wall data 102 is provided so as to be in contact with the upper surface of the floor data 103. The upper end face of the lower wall data 102 is provided so as to be in contact with the lower surface of the floor data 103. For example, if structural member data 101 are in contact with each other without overlapping, the structural member data 101 is extended in the direction of the contacting structural member data 101.

[0029] For example, in the case of Figure 9, the upper wall data 102 is extended in a direction perpendicular to the wall thickness direction DT, in this case downwards. Alternatively, the lower wall data 102 may be extended in a direction perpendicular to the wall thickness direction DT, i.e., upwards. Or, the upper wall data 102 may be extended downwards and the lower wall data 102 may be extended upwards, and these two wall data 102 may be combined into a single wall data 102. Unlike in Figure 9, when wall data 102 is provided so as to penetrate vertically, and floor data 103 is provided so as to divide the floor into left and right sections by the wall data 102, the left floor data 103 is extended in a direction perpendicular to the floor thickness direction DT, in this case to the right. Alternatively, the right floor data 103 may be extended in a direction perpendicular to the floor thickness direction DT, i.e., to the left. Or, the left floor data 103 may be extended to the right, and the right floor data 103 may be extended to the left, and these two floor data 103 may be combined into a single floor data 103.

[0030] In this way, by extending the structural member data 101, overlapping OR portions are generated between the structural member data 101, as explained with reference to Figure 7. The structural member data adjustment unit 12 assumes that these overlapping OR portions are joints J between structural members, generates joint data 105 corresponding to the joints J, and deletes the overlapping OR portions corresponding to the joint data 105 from each of the structural member data 101. As a result, the shapes of each structural member data 101 and joint data 105 are adjusted so that there are no overlapping portions between each structural member data 101 and the joint data 105, and that they are in contact with each other.

[0031] In the BIM data 100, information such as physical properties like the design strength of concrete is set for each structural member data 101. For the joint data 105 generated as described above, for example, the information set in either the wall data 102 or the floor data 103 is set as the information for the joint data 105.

[0032] The IFC data output unit 13 outputs the information regarding the reinforcement layer 110 generated as described above, and the information regarding the structural member data 101 and joint data 105 generated and adjusted as described above, as an IFC (Industry Foundation Class) file (hereinafter referred to as IFC data 120). Figure 10 is an explanatory diagram of IFC data. For example, IFC data 120 relating to a wall, i.e., IFC wall data 122, can be defined as a rectangular parallelepiped represented by the shape of the bottom surface 122b, the direction D122 in which the wall extends horizontally, and the height H122. If the IFC wall data 122 has an opening 122h, the solid calculated as the difference between the above rectangular parallelepiped and the rectangular parallelepiped corresponding to the opening 122h becomes the IFC wall data 122 corresponding to the wall. The joint data 105 is also output to the IFC data 120 in a similar format. Furthermore, information such as physical properties set for each of the structural member data 101 and joint data 105 is also output to the IFC data 120, linked to each of the structural member data 101 and joint data 105, respectively.

[0033] The BMI program 10, which performs the functions of the reinforcement layer generation unit 11, the structural member data adjustment unit 12, and the IFC data output unit 13 as described above, may be implemented as a standalone program or application, independent of the other components from the structural member data representation modification unit 21 onward, so as to read the BIM data 100 as a result of the completed design, perform the above-mentioned processing, and output the IFC data 120. In this case, the BMI program 10 may be realized by adding the functions of the reinforcement layer generation unit 11 and the structural member data adjustment unit 12 to an existing (commercially available) BIM format data used in the design of building structures, for example, by implementing them as an add-in. In this case, if the above program originally has a function for outputting IFC format data, that function may be used as the IFC data output unit 13.

[0034] Next, the structural member data representation modification unit 21, the joint data representation modification unit 22, the structural member mesh division unit 23, the joint mesh division unit 24, and the building structure mesh model generation unit 25 will be described. These components can be implemented, for example, as a mesh division program 20 or mesh division application that takes IFC data 120 as input and outputs a mesh model 150 of a building structure. First, let's explain the structural member data representation modification unit 21. The structural member data representation modification unit 21 generates the structural member data to be divided. Figure 11 is a perspective view of the structural member data to be divided. The structural member data to be divided 131 is data relating to a structural member that is the direct target of the mesh division operation in the mesh model generation system 1. The structural member data to be divided 131 includes wall data to be divided 132, which is the structural member data to be divided 131 when the structural member is a wall, and floor data to be divided 131, which is the structural member data to be divided 131 when the structural member is a floor. Figure 11 shows an example of wall data to be divided 132.

[0035] The structural member data representation modification unit 21 defines the structural member by the shape of the main surface 132f, which is the largest surface area corresponding to the floor or wall surface, and its thickness T, when the structural member is a floor or wall. In other words, the main surface 132f is a surface that extends in a plane perpendicular to the thickness direction DT of the wall or floor. More specifically, the structural member data representation modification unit 21 generates segmented structural member data 131 (segmented wall data 132) for each structural member data 101 in the IFC data 120, so that if the structural member is a wall, the structural member is represented by the shape of the main surface 132f, the thickness T, the in-plane direction in which the main surface 132f extends, and the thickness direction DT. Furthermore, the structural member data representation modification unit 21 generates segmented structural member data 131 (segmented floor data) so as to represent the structural member by the shape of the main surface, the thickness, the in-plane direction in which the main surface extends, and the thickness direction, even when the structural member is a floor. The above in-plane directions include a first in-plane direction DS1 and a second in-plane direction DS2, which are directions along each of the mutually orthogonal edge sides 132e of the main surface 132f.

[0036] By using the structural member data 131 to be divided as described above, the main surface 132f, which is provided to extend in the in-plane directions DS1 and DS2, is moved in the thickness direction DT by a thickness T, and the shape of the structural member corresponding to the structural member data 131 to be divided can be represented as the trajectory of the movement of the main surface 132f. For example, it is conceivable to define the structural member data 131 to be divided in such a way that other surfaces 132g extending in a plane including the thickness direction DT, other than the main surface 132f, are moved in a direction perpendicular to the other surfaces 132g as if being "pushed out". However, in this case, if the structural member data 131 to be divided has an opening 132h that penetrates in the thickness direction DT, the shape formed by moving the other surfaces 132g as if being "pushed out" will also include the internal space of the opening 132h, making it impossible to properly represent the shape of the structural member including the opening 132h. In contrast, as described above, by representing the structural member data 131 to be divided as a shape formed by moving the main surface 132f in the thickness direction DT, the shape of the structural member, including the opening 132h, can be faithfully represented.

[0037] In this way, the structural member data representation modification unit 21 adjusts the structural member data 101, which has been input as BIM data 100, by deleting the portion corresponding to the joint J, and outputs it as IFC data 120. Based on this, it adjusts and modifies the representation to generate the structural member data 131 to be divided.

[0038] The structural member data representation modification unit 21, if the structural member data 101 in the IFC data 120 is linked to information regarding physical properties such as the design strength of concrete, generates physical property information such as Young's modulus that is actually used in finite element method analysis based on that information, and sets that physical property information to the structural member data 131 that is to be divided and generated for the structural member data 101.

[0039] In this embodiment, the IFC data output unit 13 outputs IFC data 120, and the structural member data representation modification unit 21 generates the structural member data 131 to be divided based on this IFC data 120. Alternatively, the BMI program 10 could output an intermediate file in a format different from the IFC data 120, and the structural member data representation modification unit 21 could read this file. Specifically, one could consider using an intermediate file in which structural member data 101 as a rectangular prism is represented by a set of coordinates for eight vertices. However, extracting the shape of the main surface 132f, the in-plane direction, the thickness direction DT, the thickness T, etc., from such a set of coordinates to represent the structural member data 131 to be divided is time-consuming. In comparison, when using IFC data 120, it is easier to generate the structural member data 131 to be divided from its contents, so it is preferable to use IFC data 120 as an intermediate file.

[0040] The joint data representation modification unit 22 generates the joint data to be divided. The joint data to be divided is data relating to the joint J that is the direct target of the mesh division operation in the mesh model generation system 1. The joint data representation modification unit 22, similar to the structural member data representation modification unit 21, generates data for the joint to be divided so that the joint J is represented by the shape of one of the surfaces of the joint J as the main surface, the length in the orthogonal direction perpendicular to the main surface, the in-plane direction in which the main surface extends, and the orthogonal direction. The above-mentioned in-plane directions include the first in-plane direction and the second in-plane direction, which are directions along each of the edges of the mutually orthogonal principal surfaces. By using the division target joint data described above, similar to the division target structural member data 131, the main surface, which is provided to extend in the in-plane direction, can be moved in the orthogonal direction by the value of the length in the orthogonal direction, and the shape of the joint J corresponding to the division target joint data can be represented as the trajectory of the movement of the main surface.

[0041] In this way, the joint data representation modification unit 22 generates the division target joint data by adjusting and modifying the representation of the joint data 105, which has been generated by the structural member data adjustment unit 12 and output as IFC data 120. The joint data representation modification unit 22, if the IFC data 120 has information regarding physical properties such as the design strength of concrete linked to the joint data 105, generates physical property information such as Young's modulus that is actually used in finite element method analysis based on that information, and sets that physical property information to the divided joint data generated for the joint data 105.

[0042] The structural member mesh division unit 23 generates a structural member mesh model by dividing each of the structural member data 131 to be divided into meshes. Figure 12 is a perspective view showing the main surface of Figure 11 after being meshed in two dimensions in the first and second in-plane directions. Here, we will explain using the example of a structural member being a wall. The structural member mesh division unit 23 first divides the main surface 132f into a two-dimensional mesh in the first in-plane direction DS1 and the second in-plane direction DS2. Specifically, the structural member mesh division unit 23 divides the main surface 132f at multiple positions in the first in-plane direction DS1 by division lines ML perpendicular to the first in-plane direction DS1, and at multiple positions in the second in-plane direction DS2 by division lines ML perpendicular to the second in-plane direction DS2. Since the first in-plane direction DS1 and the second in-plane direction DS2 are directions along the orthogonal edges 132e of the main surface 132f, the two-dimensional mesh elements MT generated by this mesh division are basically quadrilateral elements. When the structural member data 131 to be divided includes an opening 132h, as shown in Figure 12, the position of the dividing line ML can be adjusted so that it overlaps with each edge of the opening 132h, thereby making the mesh elements generated by the mesh division consist only of quadrilateral elements.

[0043] Figure 13 is a perspective view showing the mesh division state of the main surface reflected at all positions in the orthogonal direction, compared to Figure 12. The structural member mesh division section 23 then moves the state of the main surface 132f that has been meshed as described above (more specifically, the division line ML) in the thickness direction DT by "pushing" it out, thereby reflecting the mesh division state at all positions in the thickness direction DT. As a result, the structural member data 131 to be divided in this state is, for example, shown as the section viewed by arrow II in Figure 13, and in the plane that appears when a cross-sectional view is taken in a plane perpendicular to the thickness direction DT, it is in a meshed state, similar to the main surface 132f, regardless of the position in the thickness direction DT at which the cross-sectional view is taken.

[0044] Figure 14 is an explanatory diagram showing the state after generating a structural member mesh model by meshing in a one-dimensional direction orthogonal to Figure 13. Then, the structural member mesh division unit 23 performs mesh division in one dimension in the thickness direction DT relative to the state shown in Figure 13. Specifically, the structural member mesh division unit 23 divides the structural member data 131 to be divided in the state shown in Figure 13 by division lines ML (division planes) perpendicular to the thickness direction DT at multiple positions in the thickness direction DT. As described above, the structural member data 131 to be divided in the state shown in Figure 13 is meshed in two dimensions in the first in-plane direction DS1 and the second in-plane direction DS2. By further meshing in one dimension in the thickness direction DT, the structural member data 131 to be divided is meshed in three dimensions as a whole. In this way, the structural member data 131 to be divided is meshed by dividing lines ML (dividing planes) that are orthogonal to each of the mutually orthogonal first in-plane direction DS1, second in-plane direction DS2, and thickness direction DT. Therefore, the mesh elements M generated by the mesh division are basically hexahedral elements M6.

[0045] Furthermore, the structural member mesh division section 23 assigns physical property information, which was set for the structural member data 131 to be divided, to each node MN located at the intersection of the division line ML. In this way, the structural member mesh division unit 23 divides the structural member data 131 to be divided into a three-dimensional mesh to generate a structural member mesh model 141.

[0046] As explained using Figure 2, when attempting to mesh a three-dimensional object with an opening 132h in a single 3D model, it is possible that a large number of tetrahedral elements M4 will be used, particularly around the opening 132h. Figure 15 is a perspective view showing the initial two-dimensional mesh division of a surface that extends in the thickness direction, distinct from the main surface. Furthermore, if we were to first mesh another surface extending in the thickness direction DT, rather than the main surface 132f, in two dimensions, and then mesh it in one dimension in a direction perpendicular to that surface, the opening 132h would not appear on this other surface, and therefore the information about the opening 132h would not be reflected in the meshing of the other surface. As a result, the position of the dividing line ML when the other surface is meshed would be shifted from the position of the edge of the opening 132h, and the area around the opening 132h may not be properly meshed by the hexahedral element M6, for example, as shown by the part indicated by the symbol ME in Figure 15. In contrast, in this embodiment, the structural member mesh division unit 23 first divides the main surface 132f into a two-dimensional mesh, and then divides it into a one-dimensional mesh in the thickness direction DT. As already explained, the structural member data 131 to be divided is basically meshed using only hexahedral elements M6.

[0047] In particular, as described above, the structural member mesh division section 23 first divides the main surface 132f into two dimensions, and then divides it into one dimension in the thickness direction DT. This makes it possible to make the size of the mesh elements M and the fineness of the mesh division different when dividing the main surface 132f into two dimensions compared to when dividing it into one dimension in the thickness direction DT. In particular, in this embodiment, the structural member mesh division section 23 divides the mesh in the thickness direction DT more finely than when dividing the main surface 132f into two dimensions. This makes it possible to accurately calculate the deformation of walls and floors in the thickness direction DT in finite element analysis.

[0048] Similarly, when the structural member is a floor, the structural member mesh division section 23 divides the main surface into a mesh in two dimensions in the first and second in-plane directions, reflects the mesh division state of the main surface at all positions in the thickness direction, and then divides the mesh in one dimension in the thickness direction, thereby dividing the structural member data 131 to be divided into a mesh in three dimensions. Furthermore, even when the structural member is a floor, the structural member mesh division section 23 assigns the physical property information set for the structural member data 131 to each node located at the intersection of the division lines.

[0049] The joint mesh division unit 24 generates a joint mesh model by dividing each of the joint data to be divided into a mesh. The joint mesh division unit 24 divides the joint data to be divided into a mesh using either the first division method described below or the second division method described thereafter.

[0050] Figure 16 is an explanatory diagram illustrating the case where the joint data to be divided is meshed using the first division method. In the first division method, the joint mesh division unit 24 generates a joint mesh model 145 by collectively dividing the joint data to be divided in three dimensions so that the structural member mesh model 141, which is generated by meshing the structural member data 131 that comes into contact with the joint data to be divided, shares the nodes MN that face the joint data to be divided.

[0051] Here, since each structural member mesh model 141 is meshed individually, in multiple structural member mesh models 141 generated based on multiple structural member data 131 that come into contact with a particular joint data to be divided, the number of nodes MN and the size of mesh elements M may not be uniform and may be inconsistent. Therefore, when the joint mesh model 145 is generated by sharing the nodes MN of each of the multiple structural member mesh models 141 and performing mesh division in three dimensions all at once, the mesh division is performed to connect the inconsistent mesh elements M, and as a result, as shown in Figure 16, tetrahedral elements M4 may be included in the mesh elements M. However, for finite element analysis, the joint can be considered a rigid body (difficult to break and not important from the perspective of seismic analysis), and even if tetrahedral elements M4 are mixed in such a part, the impact on the analysis accuracy will be limited.

[0052] Figure 17 is an explanatory diagram regarding the case where the joint data to be divided is meshed using the second division method. Figure 18 is an explanatory diagram regarding multi-point constraint conditions. In the second division method, the joint mesh division unit 24 divides the joint data to be divided in the same manner as the structural member mesh division unit 23. Specifically, the joint mesh division unit 24 divides the main surface into two dimensions in the first and second in-plane directions, reflects the mesh division state of the main surface at all positions in the orthogonal direction, and then divides the joint data to be divided into three dimensions by dividing it into one dimension in the orthogonal direction, thereby generating the joint mesh model 145.

[0053] However, in this case, as shown in Figure 18, node MN1 of the structural member mesh model 141 is not shared with the joint mesh model 145, so node MN1 of the structural member mesh model 141 and node MN2 of the joint mesh model 145 do not correspond to each other. Therefore, in this state, it is not possible to perform finite element analysis on these structural member mesh models 141 and joint mesh models 145. Therefore, when the second division method is used, the building structure mesh model generation unit 25, which will be described below, generates a building structure mesh model 150 by accumulating the structural member mesh model 141 and the joint mesh model 145, and sets multi-point constraints (MPC) at nodes MN1 and MN2 located at the interface MF between the structural member mesh model 141 and the joint mesh model 145 that are in contact with each other. As a result, when finite element analysis is performed on the mesh model 150 of the building structure, the nodes MN1 and MN2 located within the interface MF of both the structural member mesh model 141 and the joint mesh model 145 are constrained to the plane and deform, so that the behavior is appropriately transmitted between the structural member mesh model 141 and the joint mesh model 145.

[0054] The joint mesh division unit 24 assigns to each node MN the physical property information that was set for the joint data to be divided.

[0055] The building structure mesh model generation unit 25 generates a building structure mesh model 150 by integrating the structural member mesh model 141 and the joint mesh model 145. In the joint mesh division section 24, if the joint mesh model 145 is generated by the second division method, multi-point constraint conditions are set at the node MN located at the interface MF between the structural member mesh model 141 and the joint mesh model 145 that are in contact with each other, as described above. The mesh model 150 of the building structure generated in this way is used as input when performing finite element method analysis.

[0056] Next, a method for generating a mesh model using the mesh model generation system 1 described above will be explained using Figures 1 to 18 and Figure 19. Figure 19 is a flowchart of the mesh model generation method using the mesh model generation system according to this embodiment. The reinforcement layer generation unit 11 generates a reinforcement layer having a thickness corresponding to the reinforcement included in the reinforcement data from the reinforcement data (step S1). The structural member data adjustment unit 12 adjusts the shape of the structural member data 101 and generates joint data (Step S2: Structural member data adjustment step). The IFC data output unit 13 outputs information regarding the reinforcement layer 110, structural member data 101, and joint data 105 as IFC data 120.

[0057] The structural member data representation modification unit 21 adjusts the structural member data 101, which has been input as BIM data 100, by deleting the part corresponding to the joint J, and outputs it as IFC data 120. Based on this, it adjusts and modifies the representation to generate the structural member data 131 to be divided (step S3). The joint data representation modification unit 22 adjusts and modifies the representation of the joint data 105 generated by the structural member data adjustment unit 12 and output as IFC data 120, based on this data, to generate the joint data to be divided (step S4).

[0058] The structural member mesh division unit 23 generates a structural member mesh model 141 by meshing each of the structural member data 131 to be divided (Step S5: Structural Member Mesh Division Process). The joint mesh division unit 24 generates a joint mesh model 145 by meshing each of the joint data to be divided (Step S6: Joint Mesh Division Process). The building structure mesh model generation unit 25 generates a building structure mesh model 150 by integrating the structural member mesh model 141 and the joint mesh model 145 (Step S7: Building structure mesh model generation process).

[0059] The mesh model generation system 1 described above generates a three-dimensional mesh model based on BIM data 100 of a building structure constructed using concrete, wherein the BIM data 100 includes structural member data 101 corresponding to each of a plurality of structural members constituting the building structure, the system determines the overlap between the structural member data 101, assumes that the overlapping portion OR is a joint J between the structural members, generates joint data 105 corresponding to the joint J, and deletes the overlapping portion OR from each of the structural member data 101, and the structural member data The system comprises a data adjustment unit 12, a structural member mesh division unit 23 that generates a structural member mesh model 141 by meshing each of the structural member data 131 to be divided, which are generated based on each of the structural member data 101, a joint mesh division unit 24 that generates a joint mesh model 145 by meshing each of the joint data 105 to be divided, and a building structure mesh model generation unit 25 that generates a building structure mesh model 150 by integrating the structural member mesh model 141 and the joint mesh model 145. With the configuration described above, the BIM data 100 of a building structure constructed using concrete includes structural member data 101 corresponding to each of the multiple structural members that make up the building structure, such as walls and floors. If there is an overlapping portion OR of the structural member data 101, it can be considered a joint J where the structural members corresponding to the structural member data 101 are joined together. For example, if walls and floors are provided as structural members, and the corresponding structural member data 101 overlap by intersecting each other, if the overlapping portion OR of the structural member data 101 is considered a joint J, and the parts of the structural member data 101 other than the joint J are considered to be the parts of the wall, floor, etc. that correspond to the original structural members, then the interface between the part considered to be the joint J and the part considered to correspond to the original structural members is basically a single plane, and as a result, the part of the structural member data 101 that can be considered to correspond to the original structural members is considered to be a rectangular prism or a shape close to a rectangular prism. Based on this idea, the structural member data adjustment unit 12 determines the overlap between structural member data 101, assumes that the overlapping portion OR is a joint J between structural members, generates joint data 105 corresponding to the joint J, and deletes the overlapping portion OR corresponding to the joint data 105 from each of the structural member data 101. In this way, the structural member data to be divided 131 generated based on the resulting structural member data 101 from which the overlapping portion OR corresponding to the joint data 105 has been deleted is meshed to generate the structural member mesh model 141. The resulting structural member data 101 from which the overlapping portion OR corresponding to the joint data 105 has been deleted, which is the basis for generating this structural member mesh model 141, is rectangular parallelepiped as described above. For this reason, the structural member mesh model 141 is basically meshed using only hexahedral elements M6, and tetrahedral elements are unlikely to be mixed into the structural member mesh model. Thus, in the structural member mesh model 141, which is the main target of behavior observation when performing finite element method analysis, the number of tetrahedral elements M4 is reduced, so that the physical properties and characteristics of the concrete are appropriately reflected in the analysis results. On the other hand, with respect to joint J, a joint mesh model 145 is generated by meshing the joint data to be divided, which is generated based on the joint data 105. One method for generating the joint mesh model 145 is to first mesh each of the structural member data 131 to be divided to generate a structural member mesh model 141, and then mesh the structural member mesh model 141 generated by meshing the structural member data 131 that are in contact with the joint data to be divided, so that the nodes MN facing the joint data to be divided are shared by the structural member mesh model 141 that are generated. Here, since each of the structural member data 131 to be divided is meshed individually, the number of nodes MN and the size of the mesh elements M may not be uniform and may be inconsistent in the multiple structural member mesh models 141 generated for each of the structural member data 131 that are in contact with a certain joint data. Therefore, when the joint mesh model 145 is generated, the mesh is divided in a way that connects the mismatched mesh elements M, and as a result, tetrahedral elements M4 may be mixed in the joint mesh model 145. However, the joint J can be considered a rigid body (not easily broken and not important from the perspective of seismic analysis) when performing finite element method analysis, and even if tetrahedral elements M4 are mixed in such a part, the impact on the analysis accuracy will be limited. In this way, the number of tetrahedral elements M4 in the structural member mesh model 141 is reduced, and the tetrahedral elements M4 are concentrated in the joint J, which is not important for seismic analysis. As a result, the analysis accuracy of the entire mesh model 150 of the building structure is improved. Another method for generating the joint mesh model 145 is to mesh the joint data to be divided independently of the structural member mesh model 141, without sharing the nodes MN of the contacting structural member mesh model 141, thereby generating the joint mesh model 145. The structural member mesh model 141 and the joint mesh model 145 can then be associated by setting multi-point constraint conditions on the nodes MN located at the interface MF between the structural member mesh model 141 and the joint mesh model 145. If the structural member data 101 is rectangular, then the overlapping portion OR should also be basically rectangular, so the joint data 105 and the joint data to be divided are also rectangular. Therefore, the joint mesh model 145, like the structural member mesh model 141, is basically meshed using only hexahedral elements M6, and tetrahedral elements M4 are less likely to be mixed in the joint mesh model 145 as well as the structural member mesh model 141. As a result, the overall analysis accuracy of the 150 mesh model of the building structure is improved. In this way, it becomes possible to generate a 3D mesh model with high analytical accuracy based on BIM data 100 of a building structure constructed using concrete.

[0060] Furthermore, if the structural member is a floor or a wall, the system includes a structural member data representation modification unit 21 that generates structural member data 131 to be divided, representing the structural member by the shape of the main surface 132f extending in a plane perpendicular to the thickness direction DT of the floor or wall, its thickness T, the in-plane directions DS1 and DS2 along which the main surface 132f extends, and the thickness direction DT. The in-plane directions DS1 and DS2 include a first in-plane direction DS1 and a second in-plane direction DS2, which are directions along each of the mutually orthogonal edge sides 132e of the main surface 132f. The structural member mesh division unit 23, if the structural member is a floor or a wall, divides the main surface 132f into a two-dimensional mesh using the first in-plane direction DS1 and the second in-plane direction DS2, reflects the mesh division state of the main surface 132f at all positions in the thickness direction DT, and then divides the structural member data 131 to be divided into a three-dimensional mesh by dividing it into a one-dimensional mesh in the thickness direction DT. With the above configuration, if the structural member is a floor or a wall, the structural member data 131 to be divided is represented by the shape of the main surface 132f extending in a plane perpendicular to the thickness direction DT of the floor or wall, its thickness T, the in-plane directions DS1 and DS2 on which the main surface 132f extends, and the thickness direction DT. For such structural member data 131 to be divided, the structural member mesh division unit 23 first divides the main surface 132f into two dimensions using the first in-plane direction DS1 and the second in-plane direction DS2, which are directions along each of the mutually orthogonal edges 132e of the main surface 132f. Since the main surface 132f of floors and walls is basically formed in a rectangular shape, by doing so, the main surface 132f can be meshed using basically only rectangles. Furthermore, the structural member mesh division section 23 reflects the mesh division state of the main surface 132f at all positions in the thickness direction DT. As a result, at any position in the thickness direction DT of the structural member, the mesh division state is the same as that of the main surface 132f. Therefore, by performing mesh division in one dimension in the thickness direction DT in this state, the structural member data 131 to be divided is meshed in three dimensions. As already explained, the main surface 132f is basically meshed only with quadrilaterals, so as a result of the three-dimensional mesh division, a structural member mesh model 141 is generated with hexahedral elements M6 as the main mesh elements M. In particular, rectangular openings 102h, such as windows and inspection hatches, are sometimes provided in floors and walls, penetrating in the thickness direction DT. Such openings 102h are provided at the same position in the in-plane directions DS1 and DS2 at all positions in the thickness direction DT. Therefore, when meshing the main surface 132f in two dimensions, the shape of the openings 132h is taken into consideration, and for example, by aligning the mesh division lines ML with the edges of the openings 132h, the main surface 132f can be meshed mainly with rectangles. Then, by reflecting the mesh division state of the main surface 132f at all positions in the thickness direction DT and meshing in one dimension in the thickness direction DT, the structural member data 131 to be divided becomes a three-dimensional meshed state mainly with hexahedral elements M6. In this way, even when floors and walls have rectangular openings 102h, the structural member data 131 to be divided can be meshed in three dimensions using hexahedral elements M6 as the main component.

[0061] Furthermore, the joint mesh division unit 24 divides the joint data to be divided into three dimensions in a single mesh, such that the structural member mesh model 141, which is generated by meshing the structural member data 131 that comes into contact with the joint data to be divided, shares the nodes MN that face the joint data to be divided. With the above configuration, the structural member mesh model 141, which is generated by meshing the structural member data 131 that comes into contact with the joint data to be divided, shares the nodes MN facing the joint data to be divided in a three-dimensional manner. As a result, the nodes MN are shared between the adjacent structural member mesh models 141 and the joint mesh model 145 that are in contact with each other. Consequently, when the structural member mesh model 141 and the joint mesh model 145 are combined to generate the mesh model 150 of the building structure, the nodes MN between the structural member mesh model 141 and the joint mesh model 145 are consistent. In this way, a suitable mesh model 150 of the building structure that is consistent as a whole can be generated.

[0062] Furthermore, the system includes a joint data representation modification unit 22 that generates division target joint data so as to represent the joint J by using one of the surfaces of the joint J as the main surface, the shape of the main surface, the length in the orthogonal direction perpendicular to the main surface, the in-plane direction in which the main surface extends, and the orthogonal direction, wherein the in-plane direction includes a first in-plane direction and a second in-plane direction, which are directions along each of the mutually orthogonal edge sides of the main surface, and the joint mesh division unit 24 divides the main surface into a two-dimensional mesh in the first in-plane direction and the second in-plane direction, reflects the mesh division state of the main surface at all positions in the orthogonal direction, and then divides the division target joint data into a three-dimensional mesh by dividing it into a one-dimensional mesh in the orthogonal direction, and the building structure mesh model generation unit 25 sets multi-point constraint conditions at the node MN located at the interface MF of the structural member mesh model 141 and the joint mesh model 145 that are in contact with each other. With the above configuration, the data for the joint to be divided is represented by the shape of one of the surfaces of the joint J as the main surface, the length in the orthogonal direction perpendicular to the main surface, the in-plane direction in which the main surface extends, and the orthogonal direction. For such data for the joint to be divided, the joint mesh division unit 24 first divides the main surface into two dimensions using a mesh in the first in-plane direction and the second in-plane direction, which are directions along each of the mutually orthogonal edges of the main surface. Since the main surface is basically formed in a rectangular shape, by doing so, the main surface can be meshed using basically only quadrilaterals. Furthermore, the joint mesh division section 24 reflects the mesh division state of the main surface at all positions in the orthogonal direction. As a result, at any position in the orthogonal direction of the joint J, the mesh division state is the same as that of the main surface. Therefore, by performing mesh division in one dimension in the orthogonal direction in this state, the joint data to be divided is meshed in three dimensions. As already explained, the main surface is basically meshed only with quadrilaterals, so as a result of the three-dimensional mesh division, the joint mesh model 145 is generated with the hexahedral element M6 as the main mesh element M. However, as described above, if the data of the joint to be divided is meshed individually, independently of the structural member data 131 that comes into contact with the data of the joint to be divided, the nodes MN will not be shared between the structural member mesh model 141 and the joint mesh model 145. As a result, when the structural member mesh model 141 and the joint mesh model 145 are combined to generate the mesh model 150 of the building structure, there will be no consistency in the nodes MN between the structural member mesh model 141 and the joint mesh model 145. In contrast to this, in the above configuration, multi-point constraint conditions are set for the nodes MN located at the interface MF between the structural member mesh model 141 and the joint mesh model 145 that come into contact with each other. As a result, when finite element analysis is performed on the mesh model 150 of the building structure, the nodes MN located within the interface MF of both the structural member mesh model 141 and the joint mesh model 145 are constrained to a plane and deform, so that the behavior is appropriately transmitted between the structural member mesh model 141 and the joint mesh model 145. In this way, a mesh model 150 of the building structure can be generated that allows for appropriate finite element method analysis.

[0063] Furthermore, if the structural member is a floor or a wall and the structural member data 101 are in contact with each other without overlapping, the structural member data 101 are extended in a direction perpendicular to the thickness direction DT of the floor or wall to generate overlapping portions OR between the structural member data 101, and the overlapping portions OR are considered to be joints J between the structural members. The joint data 105 corresponding to the joint J is then generated, and the overlapping portions OR are deleted from each of the structural member data 101. With the configuration described above, the joint data 105 can be generated appropriately.

[0064] Furthermore, the BIM data 100 includes rebar data relating to reinforcing bars provided inside the structural member, and further comprises a rebar layer generation unit 11 that generates a rebar layer 110 having a thickness corresponding to the reinforcing bars included in the rebar data from the rebar data. With the configuration described above, information regarding reinforcing bars in the BIM data 100 can be appropriately reflected in the mesh model 150 of the building structure.

[0065] Furthermore, the above-described mesh model generation method is a mesh model generation method that generates a three-dimensional mesh model based on BIM data 100 of a building structure constructed using concrete, wherein the BIM data 100 includes structural member data 101 corresponding to each of a plurality of structural members constituting the building structure, and includes a structural member data adjustment step in which the overlap between the structural member data 101 is determined, the overlapping portion OR is considered to be a joint J between the structural members, joint data 105 corresponding to the joint J is generated, and the overlapping portion OR is deleted from each of the structural member data 101; a structural member mesh division step in which each of the structural member data 131 to be divided, generated based on each of the structural member data 101, is meshed to generate a structural member mesh model 141; a joint mesh division step in which each of the joint data 105 to be divided, generated based on each of the joint data 105, is meshed to generate a joint mesh model 145; and a building structure mesh model generation step in which the structural member mesh model 141 and the joint mesh model 145 are combined to generate a mesh model 150 of the building structure. With the configuration described above, as already explained with respect to the mesh model generation system 1, it becomes possible to generate a 3D mesh model with high analytical accuracy based on BIM data 100 of a building structure constructed using concrete.

[0066] (Modification of the first embodiment) In the embodiments described above, the case where the structural members are walls and floors was mainly explained, but the structural members may also be long members such as columns and beams. In this case as well, the structural member data adjustment unit 12, similar to the embodiment described above, determines the overlap between structural member data 101 as columns and beams and structural member data 101 as other structural members such as walls, floors, columns, and beams, and assumes that the overlapping portion OR is a joint J between structural members, generates joint data 105 corresponding to the joint J, and deletes the overlapping portion OR corresponding to the joint data 105 from each of the structural member data 101. The structural member data adjustment unit 12 can, if the structural member data 101 are in contact with each other without overlapping and the structural members are columns or beams, extend the structural member data 101 corresponding to the columns or beams in the longitudinal direction to generate overlapping OR portions between the structural member data 101, assume that the overlapping OR portion is a joint J between the structural members, generate joint data 105 corresponding to the joint J, and delete the overlapping OR portion corresponding to the joint data 105 from each of the structural member data 101.

[0067] Figure 20 is a perspective view showing the state in which the main surface of structural member data for columns and beams has been meshed in two dimensions in the first and second in-plane directions. Figure 21 is an explanatory diagram showing the state in which the mesh division state of the main surface has been reflected at all positions in the longitudinal direction compared to Figure 20, and then the mesh has been divided in one dimension in the longitudinal direction to generate a structural member mesh model. Furthermore, the structural member data representation modification unit 21 can generate the structural member data 131 to be divided by, for example, defining a surface extending in a plane perpendicular to the longitudinal direction DL of a column or beam as the main surface 132f, and representing the structural member by the shape of the main surface 132f, its length L, the in-plane directions DS1 and DS2 to which the main surface 132f extends, and the longitudinal direction DL. In this case, the structural member mesh division unit 23 can divide the structural member data 131 to be divided into three dimensions by meshing the main surface 132f in two dimensions using the first in-plane direction DS1 and the second in-plane direction DS2, reflecting the mesh division state of the main surface 132f at all positions in the longitudinal direction DL, and then meshing it in one dimension in the longitudinal direction DL, thereby generating the structural member mesh model 141.

[0068] (Second Embodiment) Next, a second embodiment will be described. Figure 22 is a block diagram of the mesh model generation system according to this embodiment. The mesh model generation system 1A of this embodiment differs from the mesh model generation system 1 of the first embodiment in the processing content of the structural member data adjustment unit 12A and the building structure mesh model generation unit 25A, and in the absence of the joint data representation modification unit 22 and the joint mesh division unit 24. In this embodiment, detailed explanations of parts that have the same configuration as the first embodiment will be omitted. The rebar layer generation unit 11 generates a rebar layer having a thickness corresponding to the rebars included in the rebar data, similar to the first embodiment described above.

[0069] The structural member data adjustment unit 12A adjusts the shape of the structural member data 101. Figure 23 is an explanatory diagram showing the state after removing the overlapping portions between structural member data from the state shown in Figure 7. In this embodiment, the structural member data adjustment unit 12A determines the overlap between structural member data 101 and adjusts the structural member data 101 so that there is no overlap between them by deleting the overlapping portion OR from one of the structural member data 101 that has an overlapping portion OR. In the example in Figure 23, the portion OR of the wall data 102 that overlaps with the floor data 103, as shown in Figure 7, is deleted, and as a result the wall data 102 is divided into two parts in the vertical direction. Thus, the structural member data adjustment unit 12A of this embodiment does not generate joint data 105 based on the overlapping OR portion between the structural member data 101, but simply deletes the overlapping OR portion from one of the structural member data 101. As a result, the shape of the structural member data 101 is adjusted so that there are no overlapping OR parts between each of the structural member data 101, and they are in contact with each other.

[0070] The IFC data output unit 13 outputs information regarding the reinforcing bar layer 110 and information regarding the structural member data 101 as IFC data 120, similar to the first embodiment described above. Furthermore, the structural member data representation modification unit 21 generates the structural member data 131 to be divided, similar to the first embodiment described above.

[0071] Then, the structural member mesh division unit 23 generates a structural member mesh model 141 by meshing each of the structural member data 131 to be divided, similar to the first embodiment described above. Figure 24 is an explanatory diagram showing the state after mesh division has been performed on the structural member data to be divided, which was generated from the state shown in Figure 23. When each of the structural member data 131 to be divided, which are arranged to be in contact with each other, is individually meshed by the structural member mesh division unit 23 to generate a structural member mesh model 141, the nodes MN of the structural member mesh model 141 are not shared among the structural member mesh models 141, as shown in Figure 24. Therefore, in this state, it is not possible to perform finite element analysis on these structural member mesh models 141. Therefore, in this second embodiment, when the building structure mesh model generation unit 25A generates a building structure mesh model 150 by accumulating structural member mesh models 141, it sets multi-point constraint conditions at the nodes MN located at each interface MF of the structural member mesh models 141 that are in contact with each other. As a result, when finite element analysis is performed on the mesh model 150 of the building structure, the nodes MN located within the interface MF between the structural member mesh models 141 are constrained to a plane and deformed, thus ensuring that the behavior is appropriately transmitted between the structural member mesh models 141.

[0072] Next, a mesh model generation method using the mesh model generation system 1A described above will be explained using Figure 25. Figure 25 is a flowchart of the mesh model generation method using the mesh model generation system according to this embodiment. The reinforcement layer generation unit 11 generates a reinforcement layer having a thickness corresponding to the reinforcement included in the reinforcement data from the reinforcement data (step S1). The structural member data adjustment unit 12A adjusts the shape of the structural member data 101 (Step S2: Structural member data adjustment process). The IFC data output unit 13 outputs information regarding the reinforcement layer 110 and information regarding the structural member data 101 as IFC data 120. The structural member data representation modification unit 21 adjusts and modifies the representation of the structural member data 101 output as IFC data 120 based on this data to generate the structural member data 131 to be divided (step S3). The structural member mesh division unit 23 generates a structural member mesh model by meshing each of the structural member data 131 to be divided (Step S5: Structural Member Mesh Division Process). The building structure mesh model generation unit 25A generates a building structure mesh model 150 by integrating the structural member mesh models 141 (Step S7: Building structure mesh model generation process).

[0073] The mesh model generation system 1A described above is a mesh model generation system 1A that generates a three-dimensional mesh model based on BIM data 100 of a building structure constructed using concrete, wherein the BIM data 100 includes structural member data 101 corresponding to each of a plurality of structural members constituting the building structure, and comprises a structural member data adjustment unit 12A that determines overlaps between the structural member data 101 and adjusts the system so that there are no overlaps between the structural member data 101 by deleting the overlapping OR from one of the structural member data 101 that have overlapping ORs, a structural member mesh division unit that generates a structural member mesh model 141 by meshing each of the structural member data 131 that are to be divided based on each of the structural member data 101, and a building structure mesh model generation unit 25A that generates a mesh model 150 of the building structure by aggregating the structural member mesh models 141. With the configuration described above, the BIM data 100 of a building structure constructed using concrete includes structural member data 101 corresponding to each of the multiple structural members that make up the building structure, such as walls and floors. In a building structure, structural members are basically formed in the shape of a rectangular parallelepiped, such as walls and floors, and when there is an overlapping portion OR of the structural member data 101, the boundary between this overlapping portion OR and the non-overlapping portion is planar. Therefore, by determining the overlap between the structural member data 101 and removing the overlapping portion OR from one of the structural member data 101 that have an overlapping portion OR, the overlap between the structural member data 101 is eliminated, and as a result, each structural member data 101 is adjusted to become a rectangular parallelepiped or a shape close to a rectangular parallelepiped. By meshing the structural member data 131 to be divided, which is generated based on the structural member data 101 that have become rectangular parallelepipeds in this way, a structural member mesh model 141 is generated. The structural member data 101, which is the basis for generating the structural member mesh model 141 and has been adjusted to eliminate overlaps, is rectangular in shape as described above. Therefore, the structural member mesh model 141 is basically meshed using only hexahedral elements M6, and tetrahedral elements M4 are unlikely to be mixed into the structural member mesh model 141. In this way, the number of tetrahedral elements M4 is reduced in the structural member mesh model 141, so that the physical properties and characteristics of the concrete are appropriately reflected in the analysis results. Furthermore, in the configuration described above, the mesh model 150 for the building structure is generated by accumulating structural member mesh models 141, which are basically composed only of hexahedral elements M6. Therefore, the mesh model 150 for the building structure is also basically composed only of hexahedral elements M6. In this way, the number of tetrahedral elements M4 included in the mesh model 150 for the building structure is reduced, and as a result, the analysis accuracy when performing finite element method analysis is improved. In this way, it becomes possible to generate a 3D mesh model with high analytical accuracy based on BIM data 100 of a building structure constructed using concrete.

[0074] Furthermore, the building structure mesh model generation unit 25A sets multi-point constraint conditions at nodes MN located at the interface MF between the structural member mesh models 141 that are in contact with each other. When there are structural member data 131 to be divided that are in contact with each other, if each of them is meshed independently and individually as described above, the nodes MN will not be shared between the structural member mesh models 141. As a result, when the structural member mesh models 141 are aggregated to generate the mesh model 150 of the building structure, there will be no consistency in the nodes MN between the structural member mesh models 141. In contrast, in the above configuration, multi-point constraint conditions are set for the nodes MN located at the interface MF of the structural member mesh models 141 that are in contact with each other. As a result, when finite element analysis is performed on the mesh model 150 of the building structure, the nodes MN located within the interface MF of both structural member mesh models 141 are constrained to the plane and deform, so that the behavior is appropriately transmitted between the structural member mesh models 141. In this way, a mesh model 150 of the building structure can be generated that allows for appropriate finite element method analysis.

[0075] Furthermore, the above-described mesh model generation method is a mesh model generation method that generates a three-dimensional mesh model based on BIM data 100 of a building structure constructed using concrete, wherein the BIM data 100 includes structural member data 101 corresponding to each of a plurality of structural members constituting the building structure, and includes a structural member data adjustment step which determines the overlap between the structural member data 101 and adjusts the structural member data 101 so that there is no overlap between them by deleting the overlapping OR from one of the structural member data 101 that has an overlapping OR, a structural member mesh division step which generates a structural member mesh model 141 by meshing each of the structural member data 131 that are to be divided based on each of the structural member data 101, and a building structure mesh model generation step which generates a mesh model 150 of the building structure by aggregating the structural member mesh models 141. With the configuration described above, as already explained with respect to the mesh model generation system 1A, it becomes possible to generate a 3D mesh model with high analytical accuracy based on BIM data 100 of a building structure constructed using concrete.

[0076] (Modified version of the second embodiment) In this embodiment as well, the structural members may be long members such as columns and beams, similar to the first embodiment. In this case, the structural member data adjustment unit 12A, as in the above embodiment, can determine overlaps between structural member data 101 as columns and beams and structural member data 101 as other structural members such as walls, floors, columns, and beams, and delete the overlapping portion OR from one of the structural member data 101 that has an overlapping portion OR.

[0077] It should be noted that the mesh model generation system and mesh model generation method of the present invention are not limited to the embodiments and modifications described above with reference to the drawings, and various other modifications are conceivable within their technical scope. For example, in the above embodiment, the BMI program 10 outputs IFC data 120 as an intermediate file, and the mesh division program 20 generates a mesh model 150 of the building structure based on it, but the system is not limited to this. The mesh model generation system may be configured so that the reinforcement layer generation unit 11, structural member data adjustment unit 12, structural member data representation modification unit 21, joint data representation modification unit 22, structural member mesh division unit 23, joint mesh division unit 24, and building structure mesh model generation unit 25 all operate on a single program without outputting an intermediate file, and the structural member data representation modification unit 21 and the joint data representation modification unit 22 can refer to the results of processing in the structural member data adjustment unit 12 without going through an intermediate file. In addition to the above, it is possible to select or replace the configurations listed in each embodiment and each variation described above, or to change them to other configurations as appropriate. [Explanation of symbols]

[0078] 1. 1A Mesh Model Generation System 12, 12A Structural Member Data Adjustment Section 13 IFC Data Output Section 21 Structural Member Data Representation Modification Section 22. Data representation modification section at the joint 23 Structural member mesh division section 24 Joint Mesh Division Section 25, 25A Building Structure Mesh Model Generation Unit 100 BIM data 101 Structural Member Data 105 Joint data 131 Structural member data to be divided 132f Main surface 132e Edge 141 Structural Member Mesh Model 145 Joint Mesh Model 150 Mesh models of building structures DS1 1st in-plane direction DS2 Second plane direction DT thickness direction J joint MN node MF interface OR overlapping parts T thickness

Claims

1. A mesh model generation system that generates a three-dimensional mesh model based on BIM data of a building structure constructed using concrete, The BIM data includes structural member data corresponding to each of the multiple structural members that constitute the building structure. A structural member data adjustment unit determines overlaps between the structural member data, assumes that the overlapping portion is a joint between the structural members, generates joint data corresponding to the joint, and deletes the overlapping portion from each of the structural member data. A structural member mesh division unit generates a structural member mesh model by meshing each of the structural member data to be divided, which is generated based on each of the aforementioned structural member data. A joint mesh division unit generates a joint mesh model by meshing each of the joint data to be divided, which is generated based on each of the aforementioned joint data, A building structure mesh model generation unit generates the mesh model of the building structure by integrating the structural member mesh model and the joint mesh model, A mesh model generation system characterized by comprising the following features.

2. If the structural member is a floor or a wall, the structural member data representation modification unit generates the structural member data to be divided so as to represent the structural member by the shape of the main surface extending in a plane perpendicular to the thickness direction of the floor or the wall, the thickness, the in-plane direction in which the main surface extends, and the thickness direction. The aforementioned in-plane directions include a first in-plane direction and a second in-plane direction, which are directions along each of the mutually orthogonal edge sides of the main surface. The structural member mesh division unit, when the structural member is a floor or a wall, divides the main surface into a mesh in two dimensions in the first and second in-plane directions, reflects the mesh division state of the main surface at all positions in the thickness direction, and then divides the mesh in one dimension in the thickness direction, thereby dividing the structural member data to be divided into a mesh in three dimensions. The mesh model generation system according to feature 1.

3. The joint mesh division unit divides the joint data to be divided into three dimensions in a single operation, such that the nodes of the structural member mesh model, which is generated by meshing the structural member data to be divided that comes into contact with the joint data to be divided, are shared with the joint data to be divided. A mesh model generation system according to claim 1 or 2, characterized by the above.

4. The joint data representation modification unit generates the division target joint data so that the joint is represented by any one of the surfaces of the joint, the shape of the main surface, the length in the orthogonal direction perpendicular to the main surface, the in-plane direction in which the main surface extends, and the orthogonal direction, wherein the surface of the joint is designated as the main surface, and the joint is represented by the orthogonal direction. The aforementioned in-plane directions include a first in-plane direction and a second in-plane direction, which are directions along each of the mutually orthogonal edge sides of the main surface. The joint mesh division section divides the main surface into a mesh in two dimensions in the first and second in-plane directions, reflects the mesh division state of the main surface at all positions in the orthogonal directions, and then divides the mesh in one dimension in the orthogonal directions, thereby dividing the joint data to be divided into a mesh in three dimensions. The aforementioned building structure mesh model generation unit sets multi-point constraint conditions at nodes located at the interface between the structural member mesh model and the joint mesh model that are in contact with each other. The mesh model generation system according to feature 1.

5. The structural member data adjustment unit, when the structural member is a floor or a wall and the structural member data are in contact with each other without overlapping, extends the structural member data in a direction perpendicular to the thickness direction of the floor or wall to generate overlapping portions between the structural member data, treats the overlapping portion as the joint between the structural members, generates joint data corresponding to the joint, and deletes the overlapping portion from each of the structural member data. The mesh model generation system according to feature 1.

6. A mesh model generation method for generating a three-dimensional mesh model based on BIM data of a building structure constructed using concrete, The BIM data includes structural member data corresponding to each of the multiple structural members that constitute the building structure. A structural member data adjustment step involves determining the overlap between the structural member data, assuming that the overlapping portion is a joint between the structural members, generating joint data corresponding to the joint, and deleting the overlapping portion from each of the structural member data. A structural member mesh division step is performed to generate a structural member mesh model by meshing each of the structural member data to be divided, which are generated based on each of the aforementioned structural member data. A joint mesh division step is performed to generate a joint mesh model by meshing each of the joint data to be divided, which is generated based on each of the aforementioned joint data. A building structure mesh model generation step, which involves integrating the structural member mesh model and the joint mesh model to generate the mesh model of the building structure, A method for generating a mesh model, characterized by including the following:

7. A mesh model generation system that generates a three-dimensional mesh model based on BIM data of a building structure constructed using concrete, The BIM data includes structural member data corresponding to each of the multiple structural members that constitute the building structure. A structural member data adjustment unit determines the overlap between the structural member data and adjusts the structural member data so that there is no overlap between them by deleting the overlapping portion from one of the structural member data having the overlapping portion. A structural member mesh division unit generates a structural member mesh model by meshing each of the structural member data to be divided, which is generated based on each of the aforementioned structural member data. A building structure mesh model generation unit generates the mesh model of the building structure by accumulating the mesh models of the structural members, A mesh model generation system characterized by comprising the following features.

8. The aforementioned building structure mesh model generation unit sets multi-point constraint conditions at nodes located at the interface between the structural member mesh models that are in contact with each other. The mesh model generation system according to feature 7.

9. A mesh model generation method for generating a three-dimensional mesh model based on BIM data of a building structure constructed using concrete, The BIM data includes structural member data corresponding to each of the multiple structural members that constitute the building structure. A structural member data adjustment step involves determining the overlap between the structural member data and adjusting the data so that there is no overlap between the structural member data by deleting the overlapping portion from one of the structural member data that has an overlapping portion. A structural member mesh division step is performed to generate a structural member mesh model by meshing each of the structural member data to be divided, which are generated based on each of the aforementioned structural member data. A building structure mesh model generation step, which involves accumulating the aforementioned structural member mesh models to generate the mesh model of the building structure, A method for generating a mesh model, characterized by including the following:

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