A grasshopper-based parameterized modeling method for spatial beam string structures

Abstract

The application discloses a kind of grasshopper-based space tensile structure parameterization modeling method, steps are as follows: picking up the building skin three-dimensional model of the tensile structure to be established;Determine the structure type and geometric control parameter, call input operator input parameter;Based on the input parameter, call the packaged tensile beam wireframe model generation operator or tensile truss wireframe model generation operator, obtain the three-dimensional wireframe model of tensile structure.The application can quickly establish the three-dimensional model of tensile structure according to building surface, and the structure type and geometric parameter can be freely controlled, the design method is simple and efficient, which provides great convenience for structure type finding, scheme comparison, calculation analysis and optimization design of space tensile structure.

Description

Technical Field

[0001] This invention belongs to the field of computer-aided structural design, specifically applied to the parametric-driven generation of spatial tensioned structures. It is a general parametric modeling method for spatial tensioned structures based on the Rhino platform and using Grasshopper visual programming technology. Background Technology

[0002] In recent years, with the rapid improvement of my country's construction level, tensioned wire structures can be seen in the roofs of various sports stadiums, transportation hubs, and industrial plants. Tensioned wire structures are a hybrid structure with the characteristics of combining rigidity and flexibility. They have a clear stress distribution mode, make great use of the characteristics of materials, and have an aesthetically pleasing appearance. Their application in large-span structures is gradually increasing.

[0003] In the structural modeling stage, for both flat and pitched roofs, designers can still use traditional design methods to draw the wireframe model of the tensioned structure step by step in CAD and other drafting software. Although time-consuming, this is achievable. However, when the structural surface is curved, or even when the curvature is inconsistent and unpredictable, traditional design methods become extremely difficult. In the structural calculation stage, unreasonable calculation results often occur, with load-bearing capacity being too high or too low, requiring adjustments to the structural model or even the architectural design itself. This necessitates designers starting from scratch. Therefore, traditional design methods are extremely inefficient, time-consuming, and flawed, urgently requiring a parametric design approach.

[0004] This invention applies parametric design as the primary method to the modeling workflow of spatial tensioned structures. It allows for the creation of structural models that closely match the building's surface, solving the problem of traditional modeling methods being unable to model irregular curved surfaces. Simultaneously, it enables free control over the structural type and geometric control parameters. Once the parameters are defined, a structural wireframe model can be generated immediately for subsequent scheme comparison and structural calculation analysis. This invention will significantly improve designers' work efficiency, optimize project design quality, enhance the team's industry competitiveness, and reduce the manpower and time costs for design firms. Summary of the Invention

[0005] The problem to be solved by this invention is to provide a parametric modeling method for spatial tensioned structures. This method is based on the Grasshopper program in Rhino 3D modeling software. By using Grasshopper to develop a battery pack program module, adjusting custom input parameters, and running the module, a wireframe model of the tensioned structure can be quickly output. This wireframe model can be directly imported into structural analysis software for further detailed design.

[0006] The present invention adopts the following technical solution: a parametric modeling method for spatial tensioned structures based on Grasshopper, comprising: picking a three-dimensional model of the building surface of the tensioned structure to be established; determining the structure type and geometric control parameters, and calling the input operator to input the parameters; based on the input geometric and type parameters, calling the packaged tensioned beam wireframe model generation operator or tensioned truss wireframe model generation operator to obtain a three-dimensional wireframe model of the tensioned structure.

[0007] The method for generating a 3D wireframe model of a tensioned beam structure using a wireframe model generation calculator is as follows: Starting from the building skin surface S1, the building surface is moved downwards by a corresponding distance according to the input setback parameters to obtain the structural surface S2. The structural surface S2 is then decomposed to obtain the structural edge lines. By comparison, the two long-span edge lines L1 and L2 are obtained. The two long-span edge lines L1 and L2 are then divided equally into vertical segments according to the input parameters to obtain a point list [P1]. Point list [P2] is flipped to obtain point list [P3]. A catenary [L3] is established between point list [P1] and point list [P3], with its sag determined by the input value. Point list [P1] and point list [P3] are connected to obtain line list [L4]. Line segments in line list [L4] are divided equally according to the number of horizontal segments specified by the input parameters to obtain point array [P4]. Rays are drawn along the points in point array [P4] and intersect with structural surface S2 to obtain upper chord node point array [P5]. Rays intersect with line array [L3] to obtain lower chord node point array [P6]. The upper chord node point array [P5] itself is connected to obtain upper chord beam line array [X1]. The lower chord node array [P6] is connected to itself to obtain the lower chord cable array [X2]. The upper chord node array [P5] and the lower chord node array [P6] are connected to obtain the middle strut array [X3]. The upper chord node array [P5] is matrix transposed and then connected to obtain the purlin array [X4]. The upper chord beam array [X1], the lower chord cable array [X2], the middle strut array [X3] and the purlin array [X4] are integrated to obtain the final three-dimensional wireframe model [X] of the tensioned beam structure.

[0008] The method for generating a 3D wireframe model of a tensioned truss structure from a wireframe model generation calculator is as follows: Starting from the building skin surface S1, the building surface is moved downwards by a corresponding distance according to the input setback parameter to obtain the structural surface S2. S2 is then decomposed to obtain the structural edge lines. By comparison, the two long-span edge lines L1 and L2 are obtained. A segment of length d is cut off from one end of each long-span edge line L1 and L2, where d is the input parameter for the lateral spacing. Then, the line is divided equally vertically according to the input parameter for the number of segments, resulting in two point matrices. Connect the two points to obtain a set [L3] in the upper chord wireframe model of the inverted triangular truss; cut off d from the other end of the two long span lines L1 and L2, and repeat the previous step to obtain another set [L4] in the upper chord wireframe model of the inverted triangular truss; cut off line segments of length d / 2 from both ends of the two long span lines L1 and L2, and repeat the previous step to obtain line group [L5]; vertically translate the lines in [L5] by h, where the value of h is the input parameter truss height, and cut off line segments of length l / 2 from both ends. The value of l is equal to the length of the line segment in [L5] divided by n, where n is the number of horizontal segments input as a parameter, resulting in the lower chord group [L6] of the inverted triangular truss. [L3] and [L4] are then divided into n equal segments to obtain the point arrays [P1] and [P2]. ​​The line group [L6] is divided into n-1 equal segments to obtain the point array [P3]. The points in the point arrays [P1][P2][P3] are grouped and connected according to different combinations to obtain the diagonal web member line group, the upper chord tie rod line group, and the purlin line group. Finally, these are connected to the chord members. Line group integration yields the overall wireframe model of the inverted triangular truss [X1]; a catenary is established through line group [L6], with its sag determined by the input parameters. A ray is drawn through point lattice [P3] to intersect the catenary, resulting in a cable node lattice [P4]. Connecting points [P3] and [P4] yields the strut line group [X2], and connecting points [P4] yields the cable line group [X3]. Finally, integrating line groups [X1][X2][X3] yields the final three-dimensional wireframe model of the tensioned truss structure [X].

[0009] The structural types of this invention include tensioned beam structures and tensioned truss structures; the geometric control parameters include the number of transverse segments, the number of longitudinal segments, the truss height, the cable sag, the transverse spacing, and the setback distance; by using variable design parameters, the three-dimensional wireframe model of the tensioned structure is generated by fitting the architectural shape surface according to the characteristics of the architectural shape.

[0010] This invention is based on the Grasshopper program in Rhino 3D modeling software. It utilizes this program to create a battery pack module, allowing for the adjustment of custom input parameters. Running the module quickly outputs a wireframe model of the tensioned cable structure. This wireframe model can be directly imported into structural analysis software for further detailed design. This invention can rapidly create a 3D model of a tensioned cable structure based on a building surface, with free control over the structural type and geometric parameters. The design method is simple and efficient, greatly facilitating structural form finding, scheme comparison, calculation analysis, and optimization design of spatial tensioned cable structures. Attached Figure Description

[0011] Figure 1 This is a flowchart of the parametric design method for tensioned structures according to the present invention;

[0012] Figure 2 This invention relates to the cluster program group for the tensioned structure;

[0013] Figure 3 This is a schematic diagram illustrating the generation of the tensioned beam structure of the present invention;

[0014] Figure 4 This is a schematic diagram illustrating the generation of the tensioned truss structure of the present invention. Detailed Implementation

[0015] This invention includes the following steps: Based on the Grasshopper program in Rhino 3D modeling software, a battery pack program module is developed using it. Custom input parameters are adjusted, and running the module quickly outputs a wireframe model of the tensioned cable structure. This wireframe model can be directly imported into structural analysis software for further detailed design.

[0016] 1. Specify the building skin used to generate the structural model;

[0017] 2. Select the structure type, define the structural geometric parameters, and complete the definition of the input parameters. The input parameters include:

[0018] Number of transverse segments: used to determine the length of the component along the span direction;

[0019] Longitudinal segment number: used to determine the spacing between components along the vertical span direction;

[0020] Truss height: Defines the truss height of a tensioned truss; invalid for tensioned beam structures.

[0021] Cable sag: Defines the sag of the lower cable;

[0022] Structural type: Either a tensioned beam structure or a tensioned truss structure can be selected;

[0023] Lateral spacing: Defines the spacing between the two upper chord members of a tensioned truss; invalid for tensioned beam structures.

[0024] Building skin: Used to specify the building skin;

[0025] Setback distance: The distance between the structural control point and the packaging surface, input according to the packaging shape and material.

[0026] 3. The core computing battery pack has been grouped into a cluster. Its computing kernel consists of two main parts: a wireframe model generator for tensioned beams and a wireframe model generator for tensioned trusses. After the parameters are defined in the previous steps, the cluster generator performs calculations and directly outputs the required wireframe model of the tensioned structure.

[0027] 3.1 The method for generating a 3D wireframe model of a tensioned beam structure from the wireframe model generator is as follows: Starting from the building skin surface S1, the building surface is moved downwards by a corresponding distance according to the input setback parameters to obtain the structural surface S2. The structural surface S2 is then decomposed to obtain the structural edge lines. By comparison, the two long-span edge lines L1 and L2 are obtained. The two long-span edge lines L1 and L2 are then divided equally into longitudinal segments according to the input parameters to obtain a point list [P1]. Point list [P2] is flipped to obtain point list [P3]. A catenary [L3] is established between point list [P1] and point list [P3], with its sag determined by the input value. Point list [P1] and point list [P3] are connected to obtain line list [L4]. Line segments in line list [L4] are divided equally according to the number of horizontal segments specified by the input parameters to obtain point array [P4]. Rays are drawn along the points in point array [P4] and intersect with structural surface S2 to obtain upper chord node point array [P5]. Rays intersect with line array [L3] to obtain lower chord node point array [P6]. The upper chord node point array [P5] itself is connected to obtain upper chord beam line array [X1]. The lower chord node array [P6] is connected to itself to obtain the lower chord cable array [X2]. The upper chord node array [P5] and the lower chord node array [P6] are connected to obtain the middle strut array [X3]. The upper chord node array [P5] is matrix transposed and then connected to obtain the purlin array [X4]. The upper chord beam array [X1], the lower chord cable array [X2], the middle strut array [X3] and the purlin array [X4] are integrated to obtain the final three-dimensional wireframe model [X] of the tensioned beam structure.

[0028] 3.2 The method for generating a 3D wireframe model of a tensioned truss structure from the wireframe model generation calculator is as follows: Starting from the building skin surface S1, the building surface is moved downwards by a corresponding distance according to the input setback parameter to obtain the structural surface S2. The structural surface S2 is decomposed to obtain the structural edge lines. By comparison, the two long-span edge lines L1 and L2 are obtained. A segment of length d is cut off from one end of the two long-span edge lines L1 and L2, where d is the input parameter for the lateral spacing. Then, the line is divided equally according to the input parameter for the longitudinal segment number to obtain two... Connect two point matrices to obtain a set [L3] in the inverted triangular truss upper chord wireframe model; cut off d from the other end of the two long span side lines L1, L2, and repeat the previous step to obtain another set [L4] in the inverted triangular truss upper chord wireframe model; cut off line segments of length d / 2 from both ends of the two long span side lines L1, L2, and repeat the previous step to obtain line group [L5]; vertically translate the lines in [L5] by h, where h is the input parameter truss height, and cut off line segments of length l / 2 from both ends. The value of l is equal to the length of the line segment in [L5] divided by n, where n is the number of horizontal segments input as a parameter, resulting in the lower chord group [L6] of the inverted triangular truss. [L3] and [L4] are divided into n equal segments to obtain the point array [P1] and [P2]. ​​The line group [L6] is divided into n-1 equal segments to obtain the point array [P3]. The points in the point arrays [P1][P2][P3] are grouped and connected according to different combinations to obtain the diagonal web member line group, the upper chord tie rod line group, and the purlin line group. Finally, these are connected to the chord... The integration of the pole and line groups yields the overall wireframe model of the inverted triangular three-dimensional truss [X1]. A catenary is established through the line group [L6], and its sag is determined according to the input parameters. A ray is drawn through the lattice [P3] to intersect the catenary, resulting in the cable node lattice [P4]. The lattice [P3] and [P4] are connected to obtain the strut line group [X2]. The lattice [P4] is then connected to obtain the cable line group [X3]. Finally, the line groups [X1][X2][X3] are integrated to obtain the final three-dimensional wireframe model of the tensioned truss structure [X].

[0029] 4. After obtaining the wireframe model of the tensioned structure, it can be imported into structural analysis software such as Midas for further detailed design.

[0030] The invention will now be further described with reference to the accompanying drawings.

[0031] like Figure 1 As shown, the parametric design method for tensioned structures consists of three main processes: extraction of building surfaces, input of control parameters, and derivation of calculations. It includes eight parametric process modules, encompassing the entire structural design process for tensioned structures, from structural modeling to analysis and design. When using this technology, structural geometric parameters can be used as control variables. By modifying and adjusting these parameters, and combining the calculation results, the structural model can be comprehensively optimized.

[0032] like Figure 2The image shows the program in the parametric design platform, including the control battery packs and cluster arithmetic unit at the input end. After defining the pre-input parameters, the arithmetic unit can perform calculations and output a wireframe model for structural design. The process steps are as follows:

[0033] 1. Specify the building surfaces used to generate the structure;

[0034] 2. Select the structural type, including tensioned beam structure and tensioned truss structure;

[0035] 3. Input the structural geometric parameters, including the number of transverse segments, the number of longitudinal segments, the truss height, cable sag, transverse spacing, and setback distance;

[0036] 4. The cluster processor performs calculations and outputs wireframe models.

[0037] When the selected structural type is a tensioned beam structure, the calculation steps are as follows: Obtain the structural surface by setback; divide the structural surface into equal parts based on the two long-span sides, connect the lines, and then divide the lines into equal parts again; then obtain the upper chord beam nodes and lower chord cable nodes through projection; finally, connect all nodes to obtain the 3D wireframe model of the tensioned beam structure. For example... Figure 3 The image shown is a schematic diagram of a generated wireframe model of a chord beam.

[0038] When the selected structural type is a tensioned truss structure, the calculation steps are as follows: First, obtain the structural surface by setback; second, based on the two long-span sides of the structural surface, perform different cuts, then equalize and connect them to obtain the upper and lower chords of the truss; third, group and connect the points on the chords according to different combinations to obtain the diagonal web member line group, the upper chord tie rod line group, and the purlin line group; fourth, project the lower chord nodes onto the catenary to obtain the cable nodes, and thus the strut and cable line groups; finally, integrate all the line groups to obtain the final 3D wireframe model of the tensioned truss structure. Figure 4 The image shown is a schematic diagram of a generated single-string truss wireframe model.

Claims

1. A parametric modeling method for spatial tensioned structures based on Grasshopper, characterized in that, include: Pick the 3D model of the building surface of the tensioned structure to be built; Determine the structure type and geometric control parameters, and then call the input arithmetic unit to input the parameters; Based on the input geometric and type parameters, the packaged wireframe model generator for tensioned beams or wireframe models for tensioned trusses is invoked to obtain a 3D wireframe model of the tensioned structure. The method for generating a 3D wireframe model of a tensioned beam structure using a wireframe model generator is as follows: Starting from the building skin surface S1, the building surface is moved downwards by a corresponding distance according to the input setback parameter to obtain the structural surface S2. The structural surface S2 is decomposed to obtain the structural edge lines. By comparison, the two long-span edge lines L1 and L2 are obtained. The two long-span edge lines L1 and L2 are divided equally vertically according to the input parameter to obtain point list [P1] and point list [P2]. ​​Point list [P2] is flipped to obtain point list [P3]. A catenary [L3] is established between point list [P1] and point list [P3], with its sag determined according to the input value. Point list [P1] and point list [P3] are connected to obtain line list [L4]. The line segments in line list [L4] are divided equally horizontally according to the input parameter to obtain a point matrix [P4]. A ray is drawn along the points in the lattice [P4] and intersects with the structural surface S2 to obtain the upper chord node lattice [P5]. The ray intersects with the linear lattice [L3] to obtain the lower chord node lattice [P6]. The upper chord node lattice [P5] itself is connected to obtain the upper chord beam linear lattice [X1]. The lower chord node lattice [P6] itself is connected to obtain the lower chord cable linear lattice [X2]. The upper chord node lattice [P5] and the lower chord node lattice [P6] are connected to obtain the intermediate strut linear lattice [X3]. The upper chord node lattice [P5] is matrix transposed and then connected to obtain the purlin linear lattice [X4]. The upper chord beam linear lattice [X1], the lower chord cable linear lattice [X2], the intermediate strut linear lattice [X3], and the purlin linear lattice [X4] are integrated to obtain the final three-dimensional wireframe model [X] of the tensioned beam structure.

2. The method according to claim 1, characterized in that, The method for generating a three-dimensional wireframe model of a tensioned truss structure from the wireframe model generator is as follows: From the building skin surface S1, the building surface is moved downward by a corresponding distance according to the input setback parameter to obtain the structural surface S2. The structural surface S2 is decomposed to obtain the structural edge lines. By comparison, the two long span edge lines L1 and L2 are obtained. A line segment of length d is cut off from one end of the two long span edge lines L1 and L2, where d is the horizontal spacing parameter input. Then, the vertical segment is divided equally according to the number of segments input according to the vertical parameter to obtain two lattices. The two lattices are connected to obtain a set [L3] in the upper chord wireframe model of the inverted triangular three-dimensional truss. After cutting off the other end of the two long-span lines L1 and L2 by d, repeat the previous step to obtain another set [L4] in the upper chord frame model of the inverted triangular truss; cut off the line segments of length d / 2 from both ends of the two long-span lines L1 and L2, and repeat the previous step to obtain line group [L5]. Vertically translate the lines in [L5] by h, where h is the input parameter truss height. Cut off the line segments of length l / 2 from both ends, where l is equal to the length of the line segment in [L5] divided by n, where n is the input parameter number of horizontal segments, to obtain the lower chord line group [L6] of the inverted triangular truss; divide [L3] and [L4] into n equal segments to obtain the lattice [P1] and [P2], and divide line group [L6] into n-1 equal segments to obtain... The points in the matrix [P1][P2][P3] are grouped and connected according to different combinations to obtain the diagonal bracing line group, the upper chord tie rod line group, and the purlin line group. Finally, they are integrated with the chord line group to obtain the overall wireframe model of the inverted triangular three-dimensional truss [X1]. The catenary is established through the line group [L6], and its sag is determined according to the input parameters. A ray is drawn through the matrix [P3] and intersects the catenary to obtain the cable node matrix [P4]. The points [P3] and [P4] are connected to obtain the strut line group [X2]. The points [P4] are connected to obtain the cable line group [X3]. Finally, the lines [X1][X2][X3] are integrated to obtain the final three-dimensional wireframe model of the tensioned truss structure [X].

3. The method according to claim 1, characterized in that, The structural types include tensioned beam structures and tensioned truss structures; the geometric control parameters include the number of transverse segments, the number of longitudinal segments, the truss height, the cable sag, the transverse spacing, and the setback; through variable design parameters, the three-dimensional wireframe model of the tensioned structure is generated by fitting the architectural surface according to the characteristics of the architectural shape.

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