Parametric modeling method of composite curved lattice shell structure with central spherical surface and external curved surface based on grasshopper

Abstract

The present invention relates to a parameterized modeling method of a combined curved surface lattice shell structure of a central spherical surface and an external curved surface based on Grasshopper. First, according to a geometric figure, the lattice shell structure is divided into a spherical surface located in the center and a curved surface located around the spherical surface. The projection of the spherical surface is taken as a central circle, the vertex of the spherical surface is taken as a central point, and the connecting lines of the intersection points of the turning lines of the curved surface and the bottom edge of the curved surface are used to form a polygon. A spatial geometric figure is established with the parameters of the polygon, the central point and the central circle, and a control point is established on the spatial geometric figure. A ridge line is established through a corresponding plug-in according to the control point, a surface model is generated according to the ridge line using the corresponding plug-in, the surface model is meshed using an isoparametric method or a mapping method, grid points are generated, and the grid points are connected to rods using a corresponding plug-in to generate a single-layer lattice shell model. The rapid modeling of the lattice shell structure can be effectively realized, the modeling efficiency can be effectively improved, and the modeling cycle can be shortened.

Description

Technical Field

[0001] The invention relates to the technical field of auxiliary building design, and in particular to a parameterized modeling method of a combined curved surface lattice shell structure of a central spherical curved surface and an external folded curved surface based on Grasshopper. Background Art

[0002] With the advancement of science and technology and the improvement of awareness of building cost saving, steel structures with beautiful shapes, reasonable force and green environmental protection have developed rapidly in the field of architectural design. The grid shell structure is a kind of steel structure building. The grid shell structure is a spatial bar system structure. It is a spatial frame based on bars, which is composed of grids according to certain rules and arranged according to the shell structure. It has the properties of both bars and shells, and has the advantages of reasonable force, beautiful shape, large span, low material consumption, easy on-site installation, and the ability to realize factory production. It is widely used in buildings such as airport terminals, high-speed railway stations, and stadiums.

[0003] The lattice shell structure is a combination of a central spherical surface and an external folded surface, wherein a spherical surface is used in the center and a folded surface connected to the spherical surface is used around the outside of the spherical surface. The lattice shell structure has the advantages of beautiful shape, good structural stability, and large internal space. However, the lattice shell structure is a combination of two surfaces, has a complex shape, and is difficult to construct a model, which hinders the application of the lattice shell structure in construction projects. Summary of the invention

[0004] In view of this, in order to overcome the shortcomings of the prior art problems, the present invention provides a parametric modeling method for a combined curved lattice shell structure of a central spherical surface and an external folded surface based on Grasshopper, which can effectively realize the rapid modeling of a combined curved lattice shell structure of a central spherical surface and an external folded surface, and can effectively improve the modeling efficiency, shorten the modeling cycle, and reduce labor intensity.

[0005] To achieve the above purpose, the technical solution provided by the present invention is: A parametric modeling method for a combined curved lattice shell structure of a central spherical curved surface and an external curved surface based on Grasshopper, characterized in that it includes the following process steps: S1. Determine the geometry of the combined lattice shell structure The lattice shell structure is divided into a spherical surface at the center and a folded surface around the spherical surface, with the projection of the spherical surface as the center circle and the vertex of the spherical surface as the center point; The lines connecting the intersection points of the turning lines with the same direction of the folding surface and the bottom edge of the folding surface form a polygon; S2. Parameter setting Set the reference plane, and set the geometric parameters of the center circle, center point and polygon according to the center circle, center point and polygon obtained in step S1, S3. Establish spatial geometry and control points According to the geometric parameters determined in step S2, a spatial geometric figure is generated through a corresponding plug-in, and a control point is established in the spatial geometric figure; S4. Establish ridge line The spatial geometry and control points obtained in the root step S3 are used to generate ridge lines through the corresponding plug-ins; S5. Build a surface model The ridge line obtained in the root step S4 is used to generate a surface model through the corresponding plug-in; S6. Establishing grid points On the surface model established in step S5, meshing the surface model is performed using an isoparametric method or a mapping method, and mesh points are generated; S7. Establish a single-layer lattice shell model According to the grid points obtained in step S6, rods are connected through corresponding plug-ins to generate a single-layer lattice shell model of a combined surface of the central spherical surface and the external folded surface.

[0006] Furthermore, the folding surface is an undulating arc-shaped folding surface, or an undulating folding plate-shaped folding surface, or a polygonal projection column-shaped folding surface.

[0007] Furthermore, the folding surface is an undulating arc-shaped folding surface or a folding plate-shaped folding surface, and the process includes the following steps: S1. Determine the geometry of the combined lattice shell structure The lattice shell structure is divided into a spherical surface at the center and an arc-shaped folded surface or a folded plate-shaped folded surface around the spherical surface, with the projection of the spherical surface as the center circle and the vertex of the spherical surface as the center point; The turning line of the arc-shaped folding surface or the turning line of the folding plate type folding surface includes a peak line and a valley line, the connecting line of the intersection point of the valley line and the bottom edge of the folding surface forms an outer ring polygon, and the connecting line of the intersection point of the peak line and the bottom edge of the folding surface forms an inner ring polygon; S2. Parameter setting Taking the plane where the outer ring polygon is located as the reference plane, according to the center circle, center point, inner ring polygon and outer ring polygon obtained in step S1, set the following parameters: center point height, center point vector height, center circle radius, number of center circle divisions, number of edges of the inner ring polygon, diameter of the circumscribed circle of the inner ring polygon, difference in diameter of the circumscribed circle between the outer ring polygon and the inner ring polygon, number of edges of the outer ring polygon, difference in height of corner fixed points between the outer ring polygon and the inner polygon, and number of external divisions; S3. Establish spatial geometry and control points According to the parameters determined in step S2, a spatial geometric figure consisting of a central circle, a central point, an inner ring polygon and an outer ring polygon is generated through a polygon plug-in, and a control point is established in the spatial geometric figure; S4. Establish ridge line The spatial geometric figures and control points obtained in the root step S3 are used to generate the bottom edge line of the curved surface, the outer arc ridge line, the center arc ridge line, the ridge line from the outer ring polygon control point to the center circle, and the ridge line from the center circle to the center point through the corresponding plug-in; S5. Build a surface model The ridge line obtained in the root step S4 is used to generate a local curved surface through the edge generation plug-in, the local curved surface is arrayed through the array plug-in to generate a complete curved surface, the local spherical surface is generated through the double-track sweep plug-in, the local spherical surface is arrayed through the array plug-in to generate a complete spherical surface, and the surface model of the combined surface of the central spherical surface and the external curved surface is generated; S6. Establishing grid points On the surface model established in step S5, meshing the surface model using an isoparametric method or a mapping method according to the number of central circle divisions and the number of external divisions set in step S2, and generating mesh points; S7. Establish a single-layer lattice shell model According to the grid points obtained in step S6, the grid points obtained in step S6 are connected by a multi-segment plug-in to generate a single-layer lattice shell model of a combined surface of the central spherical surface and the external folded surface.

[0008] Furthermore, in the step S3, when establishing a spatial geometric figure, the center point height, the center vector height, and the radius of the center circle are input through the polygon plug-in to generate a center circle; through the polygon plug-in, with the projection of the center point on the reference plane as the center of the circle, the number of edges of the inner ring polygon, the diameter of the circumscribed circle of the inner ring polygon, the number of edges of the outer ring polygon, the difference in the diameters of the circumscribed circles of the inner and outer ring polygons, and the difference in the heights of the corners of the inner ring polygon and the outer ring polygon are input to generate the inner ring polygon and the outer ring polygon, and establish a spatial geometric figure composed of the center circle, the center point, the inner ring polygon and the outer ring polygon.

[0009] Furthermore, in the step S3, the control points established include: the center point O, an angle vertex A of the inner ring polygon, angle vertices B and C of the outer ring polygon adjacent to and located on both sides of angle vertex A, the intersection point D of the valley line where angle vertex B or angle vertex C is located and the center circle, and point E located on the center circle and the line connecting the intersection point D passes through the center of the center circle.

[0010] Further, in the step S4, when establishing the ridge line, when the folding surface is an arc folding surface, the corner vertex A, corner vertex B and corner vertex C are connected by a three-point arc plug-in to generate the arc bottom edge line BAC of the folding surface; when the folding surface is a folding plate type folding surface, the corner vertex A, corner vertex B and corner vertex C are connected by a multi-segment plug-in to generate the broken line bottom edge line BAC of the folding surface, and the corner vertex B, intersection D and point E are connected by a three-point arc plug-in to generate the external arc ridge line BDE; the intersection D, center point O and point E are connected by a three-point arc plug-in to generate the center arc ridge line DOE; the arc line BD between the outer ring polygon corner vertex B and the intersection point D of the array plug-in array external arc ridge line BDE, and the arc line OD between the center point O and the intersection point D in the center arc ridge line DOE, generate the ridge line CF from the outer ring polygon corner vertex to the center circle and the ridge line FO from the center circle to the center point.

[0011] Furthermore, when the surface model is established in step S5, a local curved surface is generated through the bottom edge line BAC, the ridge line CF, the ridge line FD and the ridge line DB through the edge line generation surface plug-in, and a complete curved surface is generated through the array plug-in based on the local curved surface; through the dual-track sweeping plug-in, DF is used as the sweeping ridge line and DO and FO are used as the track sweeping to generate a local spherical surface, and a complete spherical surface is generated through the array plug-in based on the local spherical surface.

[0012] Furthermore, the folded surface is a polygonal projection cylindrical folded surface, comprising the following process steps: S1. Determine the geometry of the combined lattice shell structure The lattice shell structure is divided into a spherical surface at the center and a polygonal projection cylindrical curved surface around the spherical surface, with the projection of the spherical surface as the center circle and the vertex of the spherical surface as the center point; The turning line of the polygonal projection cylindrical curved surface is its edge line, and the line connecting the intersection of the edge line and the bottom edge of the curved surface forms the bottom polygon; S2. Parameter setting According to the center circle, center point and bottom polygon obtained in step S1, taking the plane where the bottom polygon is located as the reference plane, set the following parameters: center point height, center point vector height, center circle radius, number of center circle divisions, number of sides of the bottom polygon, diameter of the circumscribed circle of the bottom polygon, and number of external divisions; S3. Establish spatial geometry and control points According to the parameters determined in step S2, a spatial geometric figure consisting of a center circle, a center point and a bottom polygon is generated by a polygon plug-in, and a control point is established in the spatial geometric figure; When establishing a spatial geometric figure, the center point height, center sag, and radius of the center circle are input through the polygon plug-in to generate the center circle; the polygon plug-in is used to take the projection of the center point on the reference plane as the center of the circle, input the number of sides of the bottom polygon, and the diameter of the circumscribed circle of the bottom polygon to generate a polygon, and establish a spatial geometric figure consisting of the center circle, center point, and bottom polygon; The established control points include: the center point O, the corner vertex G and corner point F of the bottom polygon, the intersection point H of the edge line where the corner vertex G or the corner vertex F is located and the center circle, and the point I located on the center circle and the line connecting the intersection point H passes through the center of the center circle; S4. Establish ridge line The outer arc ridge line GHI is generated by connecting the corner vertex G, the intersection point H and the point I through the three-point arc plug-in; the center arc ridge line HOI is generated by connecting the intersection point H, the center point O and the point I through the three-point arc plug-in; the ridge line FJ from the corner vertex F of the bottom polygon to the center circle and the ridge line JO from the center circle to the center point are generated through the arc line HG between the corner vertex G and the intersection point H of the array plug-in array outer arc ridge line GHI and the arc line OH between the center point of the center arc ridge line HOI and the intersection point H; S5. Build a surface model According to the ridge line obtained in step S4, a local curved surface is generated by the edge generation surface plug-in through the ridge lines GF, FJ, JH, and HG, and a complete polygonal projection cylindrical curved surface is generated by the array plug-in according to the local curved surface; a local spherical surface is generated by the double-track sweep plug-in with HJ as the sweep ridge line and HO and JO as the tracks, and a complete spherical surface is generated by the array plug-in according to the local spherical surface; S6. Establishing grid points On the surface model established in step S5, meshing the surface model using an isoparametric method or a mapping method according to the number of central circle divisions and the number of external divisions determined in step S2, and generating mesh points; S7. Establish a single-layer lattice shell model According to the grid points obtained in step S6, the grid points obtained in step S6 are connected by a multi-segment plug-in to generate a single-layer lattice shell model of a combined curved lattice shell structure of a central spherical curved surface and an external folded surface.

[0013] Furthermore, the method further comprises step S8 of establishing a truss-type double-layer lattice shell model. According to the single-layer lattice shell model obtained in step S7, the chord node of the single-layer lattice shell model obtained in step S7 is used as the upper chord node, the upper chord node is moved downward through the lattice shell thickness plug-in to obtain the lower chord node, the lower chord node is connected through the multi-segment plug-in to generate the lower chord, and the lower chord node and the upper chord node are connected through the two-point straight line plug-in to generate the vertical web; the lower chord node and the upper chord node are numbered separately through the diversion plug-in, and the odd nodes are separated from the even nodes, according to the odd nodes of the upper chord node and the even nodes of the lower chord node, or / and, according to the even nodes of the upper chord node and the odd nodes of the lower chord node, node data is generated through the weaving plug-in, and the oblique web is generated through the multi-segment plug-in according to the node data, to obtain a truss-type double-layer lattice shell structure model of the combined surface of the central spherical surface and the external folded surface.

[0014] Furthermore, the method further comprises step S8 of establishing a triangular pyramidal double-layer lattice shell model. According to the single-layer lattice shell model obtained in step S7, the three adjacent chords of the single-layer lattice shell model are used as edge lines, and the upper chord surface of the triangular pyramid is generated by the edge line generation plug-in; the geometric center point of the upper chord surface of the pyramid is generated by the geometric center plug-in, and the normal vector passing through the geometric center point and perpendicular to the upper chord surface of the pyramid is generated by the surface analysis plug-in; the chord node of the single-layer lattice shell model obtained in step S7 is used as the upper chord node, and the upper chord node is moved along the normal of the upper chord surface of the pyramid through the lattice shell thickness plug-in to obtain the lower chord node, and the lower chord node is connected through the multi-segment plug-in to generate the lower chord; the lower chord node and the upper chord node are connected through the two-point straight line plug-in to generate the web, and the triangular pyramid double-layer lattice shell structure model of the combined surface of the central spherical surface and the external folded surface is obtained.

[0015] The beneficial effects of the present invention are: The present invention utilizes the visual characteristics of the grasshopper operation process to perform parametric modeling. The initial parameters can be adjusted at will, and the process of parameter adjustment can be dynamically displayed to achieve the goal of parametric modeling. Parametric modeling can not only generate novel spatial combination surfaces, but also improve the speed of model generation and modification, thereby improving work efficiency. Parametric modeling is a model that is established and analyzed by parameters (variables) rather than numbers. New models can be established and analyzed by simply changing the parameter values ​​in the model. Its application in auxiliary architectural design improves modeling efficiency and promotes the use of complex spatial gridshell structures. The parametric modeling design method based on grasshopper adopted by the present invention is simple and efficient, which greatly facilitates the use of finite element design software for force analysis and structural design optimization of complex spatial gridshell structures of different types and parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG1 (a) is a battery diagram of a single-layer lattice shell structure model with a combined curved surface of a central spherical surface and an outer arc-shaped curved surface and a truss-type double-layer lattice shell structure model; FIG1( b ) is a schematic diagram of the spatial geometry of a single-layer lattice shell structure having a combined curved surface of a central spherical curved surface and an outer arc-shaped curved surface; FIG1( c ) is a schematic diagram of a curved surface model of a single-layer lattice shell structure having a combined curved surface of a central spherical curved surface and an outer arc-shaped curved surface; Figure 1 (d) is a schematic diagram of a single-layer lattice shell structure model with a combined surface of a central spherical surface and an outer arc-shaped curved surface. Figure 1(e) is a generated battery diagram of new chords and webs of the truss-type double-layer lattice shell structure model in Figure 1(a); Figure 1 (f) is a schematic diagram of a truss-type double-layer lattice shell structure model with a combined curved surface of a central spherical curved surface and an outer arc-shaped curved surface; FIG2 (a) is a battery diagram of another triangular pyramidal double-layer lattice shell structure model with a combined curved surface of a central spherical surface and an outer arc-shaped curved surface; FIG2 (b) is a schematic diagram of a model of a single-layer lattice shell structure having a combined curved surface of a central spherical curved surface and an outer arc-shaped curved surface; Figure 2 (c) is a generated battery diagram of the new chord and web members of the triangular pyramidal double-layer lattice shell structure model in Figure 2 (a); Figure 2 (d) is a schematic diagram of a triangular pyramidal double-layer lattice shell structure model with a combined curved surface of a central spherical curved surface and an outer arc-shaped curved surface; FIG3 (a) is a battery diagram of a single-layer lattice shell structure model of a combined curved surface of a central spherical curved surface and an external polygonal projection cylindrical curved surface and a truss-type double-layer lattice shell structure model; FIG3 (b) is a schematic diagram of the spatial geometry of a single-layer lattice shell structure with a cylindrical curved surface projected from the outside of the central spherical curved surface by a polygon; Figure 3 (c) is a schematic diagram of the surface model of a single-layer lattice shell structure with a cylindrical curved surface projected from the outside of the central spherical curved surface; Figure 3 (d) is a schematic diagram of the model of a single-layer lattice shell structure with a cylindrical curved surface projected from the outside of the central spherical curved surface. Figure 3 (e) is a generated battery diagram of new chords and webs of the truss-type double-layer lattice shell structure model in Figure 3 (a); Figure 3 (f) is a schematic diagram of a truss-type double-layer lattice shell structure model with a cylindrical curved surface projected from the outside of the central spherical curved surface; FIG4 (a) is a battery diagram of another single-layer lattice shell structure model with a central spherical curved surface and a cylindrical curved surface with an external polygonal projection, and a triangular pyramidal double-layer lattice shell structure model; FIG4( b ) is a generated battery diagram of new chord members and web members of the triangular pyramidal double-layer lattice shell structure model in FIG4( a ); Figure 4 (c) is a schematic diagram of a triangular pyramidal double-layer lattice shell structure model with a cylindrical curved surface projected from the outside of the central spherical curved surface; Figure 5 (a) is a battery diagram of a single-layer lattice shell structure model with a central spherical surface and an external folded plate-shaped folded surface and a double-layer lattice shell structure model; FIG5( b ) is a schematic diagram of the spatial geometry of a single-layer lattice shell structure with a central spherical curved surface and an external folded plate-shaped curved surface; Figure 5 (c) is a schematic diagram of the surface model of a single-layer lattice shell structure with a folded plate-shaped folded surface outside the central spherical surface; Figure 5 (d) is a schematic diagram of the model of a single-layer lattice shell structure with a central spherical surface and an external folded plate-shaped folded surface. Figure 5(e) is a generated battery diagram of new chords and webs of the truss-type double-layer lattice shell structure model in Figure 5(a); Figure 5 (f) is a schematic diagram of a truss-type double-layer lattice shell structure model with a central spherical surface and an external folded plate-type folded surface. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments: Embodiment 1: This embodiment is to construct a single-layer lattice shell structure model of a combined curved surface of the outer arc-shaped curved surface of the center spherical surface as shown in Figure 1 (d) and a truss-type double-layer lattice shell structure model as shown in Figure 1 (f), the specific workpiece process is as follows; A parametric modeling method for a single-layer lattice shell structure and a truss-type double-layer lattice shell structure based on a combined surface of a central spherical surface and an outer arc-shaped curved surface in Grasshopper, wherein the method comprises the following process steps: S1. Determine the geometric figures that make up the lattice shell structure The lattice shell structure is divided into a spherical surface located at the center and an arc-shaped curved surface located around the spherical surface, with the projection of the spherical surface as the center circle and the vertex of the spherical surface as the center point; the turning line of the arc-shaped curved surface includes a peak line and a valley line, the line connecting the intersection point of the valley line and the bottom edge of the curved surface forms an outer ring polygon, and the line connecting the intersection point of the peak line and the bottom edge of the curved surface forms an inner ring polygon; In this embodiment, the arc-shaped curved surface has five peaks and valleys, and the intersection points of the five valley lines and the bottom edge are connected to form an outer ring pentagon, and the intersection points of the five peak lines and the bottom edge are connected to form an inner ring pentagon.

[0018] S2. Parameter setting Taking the plane where the outer ring polygon is located as the reference plane, according to the center circle, center point, inner ring polygon and outer ring polygon obtained in step S1, set the following parameters: center point height, center point vector height, center circle radius, number of center circle divisions, number of edges of the inner ring polygon, circumscribed circle diameter of the inner ring polygon, difference in circumscribed circle diameters between the outer ring polygon and the inner ring polygon, number of edges of the outer ring polygon, difference in corner fixed point heights between the outer ring polygon and the inner polygon, and number of external divisions.

[0019] In this embodiment, the center point height is determined to be 5m, the center point vector height is 25m, the center circle radius is 14m, the center circle is divided 4 times, the diameter of the circumscribed circle of the inner ring pentagon is 77m, the number of sides of the inner ring pentagon is 5, the number of sides of the outer ring pentagon is 5, the difference in diameter of the circumscribed circles of the inner and outer ring pentagons is 5m, the difference in vertex height between the inner and outer ring pentagons is 8m, and the number of external divisions is 6 times.

[0020] S3. Establish spatial geometry and control points According to the parameters determined in step S2, a spatial geometric figure consisting of a center circle, a center point, an inner ring polygon and an outer ring polygon is generated through a polygon plug-in, and a control point is established in the spatial geometric figure.

[0021] When establishing a spatial geometric figure, as shown in Figure 1 (a), input the parameters of the center point height of 5m, the center point sag of 25m, and the center circle radius of 14m to the input end of the polygon plug-in to generate a center circle. With the projection of the center point on the reference plane as the center of the circle, input the parameters of the inner ring polygon circumscribed circle diameter of 77m, the number of inner ring polygon edges of 5, the number of outer ring polygon edges of 5, the difference in the diameter of the inner and outer ring polygon circumscribed circles of 5m, and the difference in the height of the inner and outer ring polygon corners of 8m to generate an outer ring pentagon and an outer ring pentagon deformation, thus completing the establishment of the spatial geometric figure.

[0022] The established control points include: the center point O, an angle vertex A of the inner ring polygon, the angle vertices B and C of the outer ring polygon adjacent to and located on both sides of the angle vertex A, the intersection point D of the valley line where the angle vertex B or the angle vertex C is located and the center circle, and the point E located on the center circle and the line connecting the intersection point D passes through the center of the center circle. The established spatial geometric figures and control points are shown in Figure 1 (b).

[0023] S4. Establish ridge line The spatial geometric figures and control points obtained in the root step S3 are used to generate the bottom edge line of the curved surface, the outer arc ridge line, the center arc ridge line, the ridge line from the outer ring polygon control point to the center circle, and the ridge line from the center circle to the center point through the corresponding plug-in.

[0024] As shown in FIG1(b), in this embodiment, when establishing the ridge line, the three-point arc plug-in is used to connect the corner vertex A, corner vertex B and corner vertex C to generate the arc bottom edge line BAC of the curved surface; the three-point arc plug-in is used to connect the corner vertex B, the intersection point D and point E to generate the external arc ridge line BDE; the three-point arc plug-in is used to connect the intersection point D, the center point O and point E to generate the center arc ridge line DOE; the array plug-in is used to array the arc line BD between the outer ring polygon corner vertex B and the intersection point D of the external arc ridge line BDE, and the arc line OD between the center point O and the intersection point D in the center arc ridge line DOE to generate the ridge line CF from the outer ring polygon corner vertex to the center circle and the ridge line FO from the center circle to the center point.

[0025] S5. Build a surface model The ridge line obtained in the root step S4 is used to generate a local curved surface through the edge generation surface plug-in, and the local curved surface is arrayed by the array plug-in to generate a complete curved surface. The local spherical surface is generated by the double-track sweep plug-in, and the complete spherical surface is generated by the array plug-in to generate a combined surface model of the arc curved surface outside the central spherical surface.

[0026] In this embodiment, the edge generation surface plug-in is used to generate a local curved surface through the bottom edge line BAC, the ridge line CF, the ridge line FD and the ridge line DB, and the array plug-in is used to generate a complete curved surface based on the local curved surface; the double-track sweep plug-in is used to sweep the local spherical surface with DF as the sweeping ridge line and DO and FO as the tracks, and the array plug-in is used to generate a complete spherical surface based on the local spherical surface. The surface model of the single-layer lattice shell structure of the combined surface of the central spherical surface and the external arc curved surface is shown in Figure 1 (c).

[0027] S6. Establishing grid points On the surface model established in step S5, according to the number of central circle divisions and the number of external divisions determined in step S2, the surface model is meshed using an isoparametric method or a mapping method, and mesh points are generated.

[0028] S7. Establish a single-layer lattice shell model According to the grid points obtained in step S6, the grid points obtained in step S6 are connected by a multi-segment plug-in to generate a single-layer lattice shell model of a combined surface of the central spherical surface and the outer arc-shaped folded surface. The generated single-layer lattice shell model is shown in FIG1 (d).

[0029] At this point, the model of the combined curved single-layer lattice shell structure of the central spherical surface and the external arc-shaped curved surface based on Grasshopper is completed.

[0030] S8, establish a truss-type double-layer lattice shell model, As shown in FIG1(e), according to the single-layer lattice shell model obtained in step S7, the chord node of the single-layer lattice shell model obtained in step S7 is used as the upper chord node. The upper chord node is moved downward through the lattice shell thickness plug-in to obtain the lower chord node. The lower chord node is connected through the multi-segment plug-in to generate the lower chord. The lower chord node and the upper chord node are connected through the two-point straight line plug-in to generate the vertical web. The lower chord node and the upper chord node are numbered separately through the diversion plug-in, and the odd nodes are separated from the even nodes. According to the odd nodes of the upper chord node and the even nodes of the lower chord node, or / and, according to the even nodes of the upper chord node and the odd nodes of the lower chord node, the node data is generated through the weaving plug-in. According to the node data, the oblique web is generated through the multi-segment plug-in to obtain the truss-type double-layer lattice shell structure model of the combined surface of the outer arc-shaped folded surface of the central spherical surface as shown in FIG1(f).

[0031] Embodiment 2: This embodiment is a parametric modeling method for a triangular pyramidal double-layer lattice shell structure of a combined surface of a central spherical surface and an outer arc-shaped curved surface based on grasshopper as shown in Figure 2 (d). Steps S1 to S7 in Example 1 are repeated. As shown in Figure 2 (a), the parameters of the center point height of 5m, the center point vector height of 8m, and the center circle radius of 14m are input to the input end of the polygon plug-in to generate a center circle. With the projection of the center point on the reference plane as the center of the circle, the parameters of the inner ring polygon circumscribed circle diameter of 77m, the number of inner ring polygon edges of 5, the number of outer ring polygon edges of 5, the difference in the diameter of the inner and outer ring polygon circumscribed circles of 5m, and the difference in the height of the inner and outer ring polygon corners of 5m are input to the input end of the polygon plug-in. First, a single-layer lattice shell model of a combined curved surface lattice shell structure of an outer arc-shaped curved surface of a central spherical surface is established as shown in Figure 2 (b). Afterwards, as shown in FIG2(b) and FIG2(c), the three adjacent chords of the arc-shaped folded surface lattice shell in the single-layer lattice shell model are used as the edge lines, and the upper chord surface of the pyramid is generated by the edge line generation plug-in; the geometric center point of the upper chord surface of the pyramid is generated by the geometric center plug-in, and the normal vector passing through the geometric center point and perpendicular to the upper chord plane of the pyramid is generated by the surface analysis plug-in; the chord node of the single-layer lattice shell model obtained in step S7 is used as the upper chord node, and the upper chord node is moved along the normal of the upper chord surface of the pyramid through the lattice shell thickness plug-in to obtain the lower chord node, and the lower chord node is connected through the multi-segment plug-in to generate the lower chord; the lower chord node and the upper chord node are connected through the two-point straight line plug-in to generate the web, and the triangular pyramid double-layer lattice shell structure model of the combined surface of the arc-shaped folded surface outside the center spherical surface as shown in FIG2(d) is obtained.

[0032] Embodiment three: This embodiment is based on grasshopper to build a single-layer lattice shell structure model of a combined surface of a central spherical surface and an external polygonal projection cylindrical curved surface as shown in Figure 3 (d) and a truss-type double-layer lattice shell structure model as shown in Figure 3 (f). The construction process is as follows: A parametric modeling method for a composite curved surface single-layer lattice shell structure and a truss-type double-layer lattice shell structure based on a central spherical curved surface with an external polygonal projection of a cylindrical curved surface in Grasshopper, which includes the following process steps: S1. Determine the geometric figures that make up the lattice shell structure The lattice shell structure is divided into a spherical surface at the center and a polygonal projection cylindrical folded surface around the spherical surface, with the projection of the spherical surface as the center circle and the vertex of the spherical surface as the center point; the turning line of the polygonal projection cylindrical folded surface is its edge line, and the line connecting the intersection of the edge line and the bottom edge of the folded surface constitutes the bottom polygon.

[0033] In this embodiment, the lattice shell structure is divided into a spherical surface at the center and a hexagonal projection cylindrical curved surface around the spherical surface. The curved surface has six edges, and the lines connecting the intersections of the edges and the bottom edges of the curved surface form a bottom hexagon.

[0034] S2. Parameter setting According to the center circle, center point and bottom hexagon obtained in step S1, take the plane where the bottom hexagon is located as the reference plane, set the parameters: center point height, center point vector height, center circle radius, number of center circle divisions, number of sides of the bottom hexagon, diameter of the circumscribed circle of the bottom hexagon, and number of external divisions.

[0035] In this embodiment, the center point height is determined to be 5m, the center point vector height is 10m, the center circle radius is 14m, the center circle is divided 4 times, the bottom hexagon circumscribed circle diameter is 62m, the bottom hexagon has 6 sides, and the external division times are 6 times.

[0036] S3. Establish spatial geometry and control points According to the parameters determined in step S2, a spatial geometric figure consisting of a center circle, a center point and a bottom polygon is generated through a polygon plug-in, and a control point is established in the spatial geometric figure.

[0037] When establishing a spatial geometric figure, as shown in Figure 3 (a), input the parameters of the center point height of 5m, the center point sag of 10m, and the center circle radius of 14m into the input end of the polygon plug-in to generate the center circle. With the projection of the center point on the reference plane as the center of the circle, input the parameters of the bottom polygon side number of 6 and the bottom polygon circumscribed circle diameter of 62m into the input end of the polygon plug-in to generate the bottom hexagon, thus completing the establishment of the spatial geometric figure.

[0038] The established control points include: the center point O, the corner vertex G and corner point F of the bottom polygon, the intersection point H of the edge line where the corner vertex G or corner vertex F is located and the center circle, and the point I located on the center circle and whose line connecting the intersection point H passes through the center of the center circle. The established spatial geometric figures and control points are shown in Figure 3 (b).

[0039] S4. Establish ridge line The spatial geometric figures and control points obtained in the root step S3 are used to generate the bottom edge line of the curved surface, the outer arc ridge line, the center arc ridge line, the ridge line from the bottom polygon control point to the center circle, and the ridge line from the center circle to the center point through the corresponding plug-in;.

[0040] As shown in FIG3 (b), in this embodiment, when establishing the ridge line, the corner vertex G, the intersection point H and the point I are connected by a three-point arc plug-in to generate an outer arc ridge line GHI; the intersection point H, the center point O and the point I are connected by a three-point arc plug-in to generate a center arc ridge line HOI; the arc line HG between the corner vertex G of the outer arc ridge line GHI and the intersection point H, and the arc line OH between the center point of the center arc ridge line HOI and the intersection point H are arrayed by the array plug-in, to generate the ridge line FJ from the corner vertex F of the bottom polygon to the center circle and the ridge line JO from the center circle to the center point.

[0041] S5. Build a surface model According to the ridge line obtained in step S4, the local curved surface is generated by the edge generation surface plug-in through the ridge lines GF, FJ, JH, and HG, and the complete polygonal projection cylindrical curved surface is generated by the array plug-in according to the local curved surface; the double-track sweep plug-in is used to sweep the local spherical surface with HJ as the sweep ridge line and HO and JO as the track, and the complete spherical surface is generated by the array plug-in according to the local spherical surface. The surface model of the single-layer lattice shell structure of the combined surface of the central spherical surface and the external polygonal projection cylindrical curved surface is shown in Figure 3 (c).

[0042] S6. Establishing grid points On the surface model established in step S5, according to the number of central circle divisions and the number of external divisions determined in step S2, the surface model is meshed using an isoparametric method or a mapping method, and mesh points are generated.

[0043] S7. Establish a single-layer lattice shell model According to the grid points obtained in step S6, the grid points obtained in step S6 are connected by a multi-segment plug-in to generate a single-layer lattice shell model of a combined surface of the central spherical surface and the cylindrical folded surface of the external polygonal projection. The generated single-layer lattice shell model is shown in FIG3 (d).

[0044] At this point, the model of a single-layer lattice shell structure based on the combined surface of the central spherical surface and the external polygonal projection cylindrical folded surface of Grasshopper is completed.

[0045] S8, establish a truss-type double-layer lattice shell model, As shown in FIG3(e), according to the single-layer lattice shell model obtained in step S7, the chord node of the single-layer lattice shell model obtained in step S7 is used as the upper chord node. The upper chord node is moved downward through the lattice shell thickness plug-in to obtain the lower chord node. The lower chord node is connected through the multi-segment plug-in to generate the lower chord. The lower chord node and the upper chord node are connected through the two-point straight line plug-in to generate the vertical web. The lower chord node and the upper chord node are numbered separately through the diversion plug-in, and the odd nodes are separated from the even nodes. According to the odd nodes of the upper chord node and the even nodes of the lower chord node, or / and, according to the even nodes of the upper chord node and the odd nodes of the lower chord node, the node data is generated through the weaving plug-in. According to the node data, the oblique web is generated through the multi-segment plug-in to obtain the truss-type double-layer lattice shell structure of the combined surface of the outer polygonal projection column-like folded surface of the central spherical surface as shown in FIG3(f).

[0046] Embodiment 4: This embodiment is a parametric modeling method for triangular pyramidal double-layer lattice shell structure based on grasshopper to construct a combined curved surface of the central spherical curved surface with the external polygonal projection of the cylindrical folded surface as shown in Figure 4 (c). Steps S1 to S7 in Example 4 are repeated. As shown in Figure 4 (a), the parameters of the center point height of 5m, the center point vector height of 10m, and the center circle radius of 14m are input to the input end of the polygon plug-in to generate the center circle. With the projection of the center point on the reference plane as the center of the circle, the parameters of the bottom polygon circumscribed circle diameter of 62m, the number of bottom polygon edges of 6, and the number of polygon divisions of 6 are input to the input end of the polygon plug-in. First, a single-layer lattice shell model of a combined curved surface lattice shell structure of the cylindrical folded surface with the external polygonal projection of the central spherical curved surface is established. Afterwards, as shown in FIG4(b), the three adjacent chords in the polygonal projection cylindrical folded surface lattice shell of the single-layer lattice shell model are used as the edge lines, and the triangular upper chord surface of the pyramid is generated by the edge line generation plug-in; the geometric center point of the upper chord surface of the pyramid is generated by the geometric center plug-in, and the normal vector passing through the geometric center point and perpendicular to the upper chord plane of the pyramid is generated by the surface analysis plug-in; the chord node of the single-layer lattice shell model obtained in step S7 is used as the upper chord node, and the upper chord node is moved along the normal of the upper chord surface of the pyramid through the lattice shell thickness plug-in to obtain the lower chord node, and the lower chord node is connected through the multi-segment plug-in to generate the lower chord; the lower chord node and the upper chord node are connected through the two-point straight line plug-in to generate the web, and the triangular pyramid double-layer lattice shell structure model of the combined surface of the polygonal projection cylindrical folded surface outside the center spherical surface as shown in FIG4(c) is obtained.

[0047] Embodiment five: This embodiment is to construct a single-layer lattice shell structure model of a combined surface of the central spherical surface and the external folded plate-type folded surface as shown in Figure 5 (d) and a truss-type double-layer lattice shell structure model as shown in Figure 5 (f), the specific workpiece process is as follows; A parametric modeling method for a single-layer lattice shell structure and a truss-type double-layer lattice shell structure of a combined surface of a central spherical surface and an external folded plate-shaped folded surface based on Grasshopper, which includes the following process steps: S1. Determine the geometry of the combined lattice shell structure The lattice shell structure is divided into a spherical surface located in the center and a folded plate-type folded surface located around the spherical surface, with the projection of the spherical surface as the center circle and the vertex of the spherical surface as the center point; the turning lines of the folded plate-type folded surface include peak lines and valley lines, the lines connecting the intersection points of the valley lines and the bottom edge of the folded surface form an outer ring polygon, and the lines connecting the intersection points of the peak lines and the bottom edge of the folded surface form an inner ring polygon.

[0048] In this embodiment, the folded plate type folding surface has seven peaks and valleys, and the intersection points of the seven valley lines and the bottom edge of the folding surface are connected to form an outer ring heptagon, and the seven peak lines and the intersection points of the bottom edge of the folding surface are connected to form an inner ring heptagon.

[0049] S2. Parameter setting Taking the plane where the outer ring polygon is located as the reference plane, according to the center circle, center point, inner ring polygon and outer ring polygon obtained in step S1, set the following parameters: center point height, center point vector height, center circle radius, number of center circle divisions, number of edges of the inner ring polygon, circumscribed circle diameter of the inner ring polygon, difference in circumscribed circle diameters between the outer ring polygon and the inner ring polygon, number of edges of the outer ring polygon, difference in corner fixed point heights between the outer ring polygon and the inner polygon, and number of external divisions.

[0050] In this embodiment, the center point height is determined to be 5m, the center point vector height is 12m, the center circle radius is 14m, the center circle is divided 4 times, the number of edges of the inner ring polygon is 7, the number of edges of the outer ring polygon is 7, the diameter of the circumscribed circle of the inner ring polygon is 65m, the difference in diameters of the circumscribed circles of the inner and outer ring polygons is 5m, the difference in height between the corner vertices of the inner and outer ring polygons is 6m, and the number of external divisions is 6 times.

[0051] S3. Establish spatial geometry and control points According to the parameters determined in step S2, a spatial geometric figure of a center circle, an inner ring polygon and an outer ring polygon is generated through a polygon plug-in, and a control point is established in the spatial geometric figure.

[0052] When establishing a spatial geometric figure, as shown in Figure 5 (a), input the parameters of the center point height of 5m, the center point sag of 8m, and the center circle radius of 14m into the input end of the polygon plug-in to generate the center circle. With the projection of the center point on the reference plane as the center of the circle, input the parameters of the outer ring polygon number of 7, the inner and outer ring polygon circumscribed circle diameter difference of 5m, the inner ring polygon circumscribed circle diameter of 77m, the inner ring polygon number of 7, and the inner ring polygon and outer ring polygon corner vertex height difference of 5m into the input end of the polygon plug-in to generate the outer ring heptagon and the outer ring heptagon, thus completing the establishment of the spatial geometric figure.

[0053] The established control points include: the center point O, an angle vertex A of the inner ring polygon, the angle vertices B and C of the outer ring polygon adjacent to and located on both sides of the angle vertex A, the intersection point D of the valley line where the angle vertex B or the angle vertex C is located and the center circle, and the point E located on the center circle and the line connecting the intersection point D passes through the center of the center circle. The established spatial geometric figures and control points are shown in Figure 5 (b).

[0054] S4. Establish ridge line The spatial geometric figures and control points obtained in the root step S3 are used to generate the bottom edge line of the curved surface, the outer arc ridge line, the center arc ridge line, the ridge line from the outer ring polygon control point to the center circle, and the ridge line from the center circle to the center point through the corresponding plug-in.

[0055] As shown in FIG5(b), in this embodiment, when establishing the ridge line, the corner vertex A, corner vertex B and corner vertex C are connected by a multi-segment plug-in to generate the broken line bottom edge line BAC of the curved surface; the outer arc ridge line BDE is generated by connecting the corner vertex B, the intersection point D and the point E by a three-point arc plug-in; the center arc ridge line DOE is generated by connecting the intersection point D, the center point O and the point E by a three-point arc plug-in; the arc line BD between the outer ring polygon corner vertex B and the intersection point D of the array plug-in array outer arc ridge line BDE, and the arc line OD between the center point O and the intersection point D in the center arc ridge line DOE, generate the ridge line CF from the outer ring polygon corner vertex to the center circle and the ridge line FO from the center circle to the center point.

[0056] S5. Build a surface model The ridge line obtained in the root step S4 is used to generate a local curved surface through the edge generation surface plug-in, and the local curved surface is arrayed by the array plug-in to generate a complete curved surface. The local spherical surface is generated by the double-track sweep plug-in, and the complete spherical surface is generated by the array plug-in to generate a combined surface model of the central spherical surface and the external folded plate-type curved surface.

[0057] In this embodiment, the edge generation surface plug-in is used to generate a local curved surface through the bottom edge line BAC, the ridge line CF, the ridge line FD and the ridge line DB, and the complete curved surface is generated through the array plug-in based on the local curved surface; the double track sweep plug-in is used to sweep the local spherical surface with DF as the sweeping ridge line and DO and FO as the track, and the complete spherical surface is generated through the array plug-in based on the local spherical surface. The surface model of the single-layer lattice shell structure of the combined surface of the central spherical surface and the external folded plate type curved surface is shown in Figure 5 (c).

[0058] S6. Establishing grid points On the surface model established in step S5, according to the number of central circle divisions and the number of external divisions determined in step S2, the surface model is meshed using an isoparametric method or a mapping method, and mesh points are generated.

[0059] S7. Establish a single-layer lattice shell model According to the grid points obtained in step S6, the grid points obtained in step S6 are connected by a multi-segment plug-in to generate a single-layer lattice shell model of a combined surface of a central spherical surface and an external folded plate-shaped folded surface. The generated single-layer lattice shell model is shown in FIG5(d).

[0060] At this point, the model of a single-layer lattice shell structure with a combined surface of a central spherical surface and an external folded plate-shaped folded surface based on Grasshopper is completed.

[0061] S8, establish a truss-type double-layer lattice shell model, As shown in FIG5(e), according to the single-layer lattice shell model obtained in step S7, the chord node of the single-layer lattice shell model obtained in step S7 is used as the upper chord node. The upper chord node is moved downward through the lattice shell thickness plug-in to obtain the lower chord node. The lower chord node is connected through the multi-segment plug-in to generate the lower chord. The lower chord node and the upper chord node are connected through the two-point straight line plug-in to generate the vertical web. The lower chord node and the upper chord node are numbered separately through the diversion plug-in, and the odd nodes are separated from the even nodes. According to the odd nodes of the upper chord node and the even nodes of the lower chord node, or / and, according to the even nodes of the upper chord node and the odd nodes of the lower chord node, the node data is generated through the weaving plug-in. According to the node data, the oblique web is generated through the multi-segment plug-in to obtain the truss-type double-layer lattice shell structure of the combined surface of the central spherical surface and the external folded plate-type folded surface as shown in FIG5(f).

[0062] It should be noted that the above embodiments are illustrative of the technical solution of the present invention rather than limiting. Equivalent substitutions made by ordinary technicians in the relevant technical field or other modifications made according to the prior art should be included in the scope of rights required by the present invention as long as they do not exceed the concept and scope of the technical solution of the present invention.

Claims

1. A parametric modeling method for a combined curved lattice shell structure of a central spherical surface and an external curved surface based on Grasshopper, characterized in that: The process steps include: S1. Determine the geometry of the combined lattice shell structure The lattice shell structure is divided into a spherical surface at the center and a folded surface around the spherical surface, with the projection of the spherical surface as the center circle and the vertex of the spherical surface as the center point; The lines connecting the intersection points of the turning lines with the same direction of the folding surface and the bottom edge of the folding surface form a polygon; S2. Parameter setting Setting a reference plane, and setting geometric parameters of the center circle, center point and polygon according to the center circle, center point and polygon obtained in step S1; S3. Establish spatial geometry and control points According to the geometric parameters determined in step S2, a spatial geometric figure is generated through a corresponding plug-in, and a control point is established in the spatial geometric figure; S4. Establish ridge line The spatial geometry and control points obtained in the root step S3 are used to generate ridge lines through the corresponding plug-ins; S5. Build a surface model The ridge line obtained in the root step S4 is used to generate a surface model through the corresponding plug-in; S6. Establishing grid points On the surface model established in step S5, meshing the surface model is performed using an isoparametric method or a mapping method, and mesh points are generated; S7. Establish a single-layer lattice shell model According to the grid points obtained in step S6, rods are connected through corresponding plug-ins to generate a single-layer lattice shell model of a combined curved lattice shell structure of a central spherical surface and an external folded surface.

2. The parametric modeling method of the combined curved lattice shell structure of the central spherical curved surface and the external folded surface based on Grasshopper according to claim 1 is characterized by: The folding surface is an undulating arc-shaped folding surface, or an undulating folding plate-shaped folding surface, or a polygonal projection-like column-shaped folding surface.

3. The parametric modeling method of the combined curved surface lattice shell structure of the central spherical surface and the external folded surface based on Grasshopper according to claim 2 is characterized by: The folding surface is an undulating arc-shaped folding surface or a folding plate-shaped folding surface, and the process includes the following steps: S1. Determine the geometry of the combined lattice shell structure The lattice shell structure is divided into a spherical surface at the center and an arc-shaped folded surface or a folded plate-shaped folded surface around the spherical surface, with the projection of the spherical surface as the center circle and the vertex of the spherical surface as the center point; The turning line of the arc-shaped folding surface or the turning line of the folding plate type folding surface includes a peak line and a valley line, the connecting line of the intersection point of the valley line and the bottom edge of the folding surface forms an outer ring polygon, and the connecting line of the intersection point of the peak line and the bottom edge of the folding surface forms an inner ring polygon; S2. Parameter setting Taking the plane where the outer ring polygon is located as the reference plane, according to the center circle, center point, inner ring polygon and outer ring polygon obtained in step S1, set the following parameters: center point height, center point vector height, center circle radius, number of center circle divisions, number of edges of the inner ring polygon, diameter of the circumscribed circle of the inner ring polygon, difference in diameter of the circumscribed circle between the outer ring polygon and the inner ring polygon, number of edges of the outer ring polygon, difference in height of corner fixed points between the outer ring polygon and the inner polygon, and number of external divisions; S3. Establish spatial geometry and control points According to the parameters determined in step S2, a spatial geometric figure consisting of a central circle, a central point, an inner ring polygon and an outer ring polygon is generated through a polygon plug-in, and a control point is established in the spatial geometric figure; S4. Establish ridge line The spatial geometric figures and control points obtained in the root step S3 are used to generate the bottom edge line of the curved surface, the outer arc ridge line, the center arc ridge line, the ridge line from the outer ring polygon control point to the center circle, and the ridge line from the center circle to the center point through the corresponding plug-in; S5. Build a surface model The ridge line obtained in the root step S4 is used to generate a local curved surface through the edge generation plug-in, the local curved surface is arrayed through the array plug-in to generate a complete curved surface, the local spherical surface is generated through the double-track sweep plug-in, the local spherical surface is arrayed through the array plug-in to generate a complete spherical surface, and the surface model of the combined surface of the central spherical surface and the external curved surface is generated; S6. Establishing grid points On the surface model established in step S5, meshing the surface model using an isoparametric method or a mapping method according to the number of central circle divisions and the number of external divisions set in step S2, and generating mesh points; S7. Establish a single-layer lattice shell model According to the grid points obtained in step S6, the grid points obtained in step S6 are connected by a multi-segment plug-in to generate a single-layer lattice shell model of a combined surface of the central spherical surface and the external folded surface.

4. The parametric modeling method of the combined curved lattice shell structure of the central spherical curved surface and the external folded surface based on Grasshopper according to claim 3 is characterized by: In the step S3, when establishing a spatial geometric figure, the center point height, center vector height, and radius / diameter of the center circle are input through the polygon plug-in to generate the center circle; through the polygon plug-in, with the projection of the center point on the reference plane as the center of the circle, the number of edges of the inner ring polygon, the diameter of the circumscribed circle of the inner ring polygon, the number of edges of the outer ring polygon, the difference in diameters of the circumscribed circles of the inner and outer ring polygons, and the difference in height between the corners of the inner ring polygon and the outer ring polygon are input to generate the inner ring polygon and the outer ring polygon, and establish a spatial geometric figure composed of the center circle, the center point, the inner ring polygon, and the outer ring polygon.

5. The parametric modeling method of the combined curved lattice shell structure of the central spherical curved surface and the external folded surface based on Grasshopper according to claim 4 is characterized by: In the step S3, the control points established include: the center point O, an angle vertex A of the inner ring polygon, angle vertices B and C of the outer ring polygon adjacent to and located on both sides of angle vertex A, the intersection point D of the valley line where angle vertex B or angle vertex C is located and the center circle, and point E located on the center circle and the line connecting the intersection point D passes through the center of the center circle.

6. The parametric modeling method of the combined curved lattice shell structure of the central spherical curved surface and the external curved surface based on Grasshopper according to claim 5 is characterized by: In the step S4, when establishing the ridge line, when the folding surface is an arc folding surface, the corner vertex A, corner vertex B and corner vertex C are connected through a three-point arc plug-in to generate the arc bottom edge line BAC of the folding surface; when the folding surface is a folding plate type folding surface, the corner vertex A, corner vertex B and corner vertex C are connected through a multi-segment plug-in to generate the folded line bottom edge line BAC of the folding surface, and the corner vertex B, intersection D and point E are connected through a three-point arc plug-in to generate an external arc ridge line BDE; the intersection D, center point O and point E are connected through a three-point arc plug-in to generate a center arc ridge line DOE; the arc line BD between the outer ring polygon corner vertex B and the intersection point D of the array plug-in array external arc ridge line BDE, and the arc line OD between the center point O and the intersection point D in the center arc ridge line DOE, generate the ridge line CF from the outer ring polygon corner vertex to the center circle and the ridge line FO from the center circle to the center point.

7. The parametric modeling method of the combined curved lattice shell structure of the central spherical curved surface and the external folded surface based on Grasshopper according to claim 6 is characterized by: When the surface model is established in step S5, a local curved surface is generated through the bottom edge line BAC, the ridge line CF, the ridge line FD and the ridge line DB through the edge generation surface plug-in, and a complete curved surface is generated through the array plug-in based on the local curved surface; through the dual-track sweep plug-in, DF is used as the sweeping ridge line and DO and FO are used as the track sweeping to generate a local spherical surface, and a complete spherical surface is generated through the array plug-in based on the local spherical surface.

8. The parametric modeling method of the combined curved lattice shell structure of the central spherical curved surface and the external curved surface based on Grasshopper according to claim 2 is characterized by: The folded surface is a polygonal projection cylindrical folded surface, which includes the following process steps: S1. Determine the geometry of the combined lattice shell structure The lattice shell structure is divided into a spherical surface at the center and a polygonal projection cylindrical curved surface around the spherical surface, with the projection of the spherical surface as the center circle and the vertex of the spherical surface as the center point; The turning line of the polygonal projection cylindrical curved surface is its edge line, and the line connecting the intersection of the edge line and the bottom edge of the curved surface forms the bottom polygon; S2. Parameter setting According to the center circle, center point and bottom polygon obtained in step S1, taking the plane where the bottom polygon is located as the reference plane, set the following parameters: center point height, center point vector height, center circle radius, number of center circle divisions, number of sides of the bottom polygon, diameter of the circumscribed circle of the bottom polygon, and number of external divisions; S3. Establish spatial geometry and control points According to the parameters determined in step S2, a spatial geometric figure consisting of a center circle, a center point and a bottom polygon is generated by a polygon plug-in, and a control point is established in the spatial geometric figure; When creating spatial geometric figures, use the polygon plug-in to input the center point height, center sag height, and center circle radius to generate the center circle; Through the polygon plug-in, take the projection of the center point on the reference plane as the center of the circle, input the number of sides of the bottom polygon and the diameter of the circumscribed circle of the bottom polygon to generate the bottom polygon, and establish a spatial geometric figure composed of the center circle, center point and bottom polygon; The established control points include: the center point O, the corner vertex G and corner point F of the bottom polygon, the intersection point H of the edge line where the corner vertex G or the corner vertex F is located and the center circle, and the point I located on the center circle and the line connecting the intersection point H passes through the center of the center circle; S4. Establish ridge line The outer arc ridge line GHI is generated by connecting the corner vertex G, the intersection point H and the point I through the three-point arc plug-in; the center arc ridge line HOI is generated by connecting the intersection point H, the center point O and the point I through the three-point arc plug-in; the ridge line FJ from the corner vertex F of the bottom polygon to the center circle and the ridge line JO from the center circle to the center point are generated through the arc line HG between the corner vertex G and the intersection point H of the array plug-in array outer arc ridge line GHI and the arc line OH between the center point of the center arc ridge line HOI and the intersection point H; S5. Build a surface model According to the ridge line obtained in step S4, a local curved surface is generated by the edge generation surface plug-in through the ridge lines GF, FJ, JH, and HG, and a complete polygonal projection cylindrical curved surface is generated by the array plug-in according to the local curved surface; a local spherical surface is generated by the double-track sweep plug-in with HJ as the sweep ridge line and HO and JO as the tracks, and a complete spherical surface is generated by the array plug-in according to the local spherical surface; S6. Establishing grid points On the surface model established in step S5, meshing the surface model using an isoparametric method or a mapping method according to the number of central circle divisions and the number of external divisions determined in step S2, and generating mesh points; S7. Establish a single-layer lattice shell model According to the grid points obtained in step S6, the grid points obtained in step S6 are connected by a multi-segment plug-in to generate a single-layer lattice shell model of a combined surface of the central spherical surface and the external folded surface.

9. The parametric modeling method for a combined curved lattice shell structure of a central spherical curved surface and an external curved surface based on Grasshopper according to any one of claims 1 to 8, characterized in that: The step S8 is also included, establishing a truss-type double-layer lattice shell model, According to the single-layer lattice shell model obtained in step S7, the chord node of the single-layer lattice shell model obtained in step S7 is used as the upper chord node. Through the lattice shell thickness plug-in, the upper chord node is moved downward to obtain the lower chord node, the lower chord node is connected through a multi-segment plug-in to generate a lower chord, and the lower chord node and the upper chord node are connected through a two-point straight line plug-in to generate a vertical web member; the lower chord node and the upper chord node are numbered separately through a shunt plug-in, and the odd nodes are separated from the even nodes, according to the odd nodes of the upper chord node and the even nodes of the lower chord node, or / and, according to the even nodes of the upper chord node and the odd nodes of the lower chord node, node data is generated through a weaving plug-in, and an oblique web is generated through a multi-segment plug-in according to the node data, to obtain a truss-type double-layer lattice shell structure model of a combined surface of the central spherical surface and the external folded surface.

10. The parametric modeling method of the combined curved lattice shell structure of the central spherical curved surface and the external curved surface based on Grasshopper according to any one of claims 1 to 8, characterized in that: The step S8 is also included, in which a triangular pyramid double-layer lattice shell model is established. According to the single-layer lattice shell model obtained in step S7, the three adjacent chords of the single-layer lattice shell model are used as edge lines, and the upper chord surface of the triangular pyramid is generated by the edge line generation plug-in; the geometric center point of the upper chord surface of the pyramid is generated by the geometric center plug-in, and the normal vector passing through the geometric center point and perpendicular to the upper chord surface of the pyramid is generated by the surface analysis plug-in; the chord node of the single-layer lattice shell model obtained in step S7 is used as the upper chord node, and the upper chord node is moved along the normal of the upper chord surface of the pyramid through the lattice shell thickness plug-in to obtain the lower chord node, and the lower chord node is connected through the multi-segment plug-in to generate the lower chord; the lower chord node and the upper chord node are connected through the two-point straight line plug-in to generate the web, and the triangular pyramid double-layer lattice shell structure model of the combined surface of the central spherical surface and the external folded surface is obtained.

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