CN-121997600-A - Grasshopper-based polygonal projection space torsion surface reticulated shell parametric modeling method

CN121997600ACN 121997600 ACN121997600 ACN 121997600ACN-121997600-A

Abstract

The invention discloses a Grasshopper-based polygonal projection space torsion curved surface net shell parameterization modeling method which comprises the following steps of S1, setting geometric parameters of a net shell model through an input plug-in a Grasshopper platform to obtain a corresponding space curved surface net shell surface projection surface, S2, connecting all vertexes of the projection surface to generate a ridge line forming a net shell curved surface, constructing a polygonal projection space torsion curved surface through curve generation operation based on the ridge line, S3, dividing the space torsion curved surface into grids through an isoparametric method or a mapping method to generate grid points, and S4, based on the grid points, generating a single-layer polygonal projection space torsion curved surface net shell structure through a multi-section line connection plug-in. The method is used for solving the technical problems of difficult modeling, low modeling efficiency and low recycling rate of the existing space latticed shell structure with complex modeling.

Inventors

ZHANG SHUAILIANG
DU WENFENG
LI SHIANG
GAO CHAOYANG
JIA HENG
WU HAO

Assignees

河南大学

Dates

Publication Date: 20260508
Application Date: 20260128

Claims (10)

1. The parameterized modeling method for the polygonal projection space torsion surface reticulated shell based on Grasshopper is characterized by comprising the following steps of: step S1, setting geometric parameters of a net shell model in a Grasshopper platform through an input plug-in unit to obtain a corresponding space curved net shell surface projection surface; S2, connecting the vertexes of the projection surface to generate a ridge line forming a curved surface of the reticulated shell, and constructing a polygonal projection space torsion curved surface through curved surface generation operation based on the ridge line; step S3, performing grid division on the space torsion surface by using an isoparametric method or a mapping method to generate grid points; S4, generating a single-layer polygonal projection space torsion surface reticulated shell structure through a multi-section line connection plug-in unit based on the grid points; The geometric parameters in the step S1 comprise the radius and the edge number of the bottom polygon, the height of the center vertex and the extension length and the height of the external corner point, and the setting method of the geometric parameters comprises the following steps: generating a bottom polygon by using a polygon plug-in, and setting parameters of the radius and the edge number of the bottom polygon through an input plug-in so as to control the shape of the polygon; acquiring a bottom polygon center point, and obtaining the height of a center vertex by using a generating point plug-in and assigning a Z coordinate; The line segment formed by connecting the polygon center point and the polygon edge inner middle point is extended outwards by utilizing the generated extension line segment plug-in, and the extension length parameter is used for controlling the projection plane position of the external corner point; and the generating point plug-in is used again, and the space height of the external corner is parameterized and adjusted by assigning a value to the Z coordinate of the external corner.
2. The method for parameterizing and modeling a polygonal projection space torsion surface reticulated shell based on Grasshopper as claimed in claim 1, wherein the step S2 is used for constructing a first type of polygonal projection space torsion surface, and specifically includes: s2.1, generating a ridge line connecting the central vertex with the polygon corner point and the external corner point; and S2.2, generating a local space torsion curved surface based on the ridge line, and forming a complete first polygonal projection space torsion curved surface through array operation.
3. The method for parameterizing and modeling a polygonal projection space torsion surface reticulated shell based on Grasshopper as claimed in claim 1, wherein the step S2 is used for constructing a second type of polygonal projection space torsion surface, and specifically includes: S2.1', generating a ridge line connecting the central vertex with the polygon corner point and the external corner point; S2.2', generating a local space torsion surface based on the ridge line; S2.3', cutting off a curved surface part outside the bottom polygonal projection area by using a mapping pruning method; and S2.4', forming a complete second type of polygonal projection space torsion surface through array operation.
4. A method for parameterizing a curved-surface reticulated shell of polygonal projection space based on Grasshopper as claimed in any one of claims 2 or 3, further comprising a step S5 of generating a truss type double-layer reticulated shell, wherein the step is to move the nodes of the single-layer reticulated shell to obtain nodes of a lower chord layer, and connect the nodes of the upper chord layer and the lower chord layer to form the double-layer reticulated shell, and specifically comprises the following steps: S5.1, taking the node of the single-layer reticulated shell as an upper chord layer node, and generating a lower chord layer node by shifting along the normal direction or the vertical direction; s5.2, connecting the lower chord layer nodes to form a lower chord; And S5.3, connecting the corresponding upper chord layer node with the lower chord layer node to form a web member system, wherein the web member system comprises a diagonal web member generated by pairing and connecting the upper chord node and the lower chord node with different parity.
5. A method for parameterizing a curved-surface reticulated shell of polygonal projection space based on Grasshopper as claimed in any one of claims 2 or 3, further comprising a step S5' of generating a conical double-layer reticulated shell, wherein the lower chord layer node is obtained by moving a single-layer reticulated shell node, and the upper chord layer node and the lower chord layer node are connected to form the double-layer reticulated shell, specifically comprising the following steps: S5.1', taking the nodes of the single-layer net shell as upper chord nodes, and generating lower chord nodes along the normal offset of the upper chord surfaces of all grid cells; S5.2', connecting the lower chord nodes to form a lower chord; And S5.3', connecting each upper chord node with the corresponding lower chord node and the adjacent lower chord nodes to form a triangular cone-shaped or quadrangular cone-shaped web member system.
6. The parameterized modeling method for the polygonal projection space torsion surface reticulated shell based on Grasshopper is characterized by comprising the following steps of: Step S1a, setting geometric parameters of a net shell model in a Grasshopper platform through an input plug-in unit to obtain a corresponding space curved net shell surface projection surface; s2a, connecting vertexes of a projection surface to generate a ridge line forming a curved surface of the net shell, and constructing a polygonal projection space torsion curved surface through curved surface generation operation based on the ridge line; step S3a, performing grid division on the space torsion surface by utilizing an isoparametric method or a mapping method to generate grid points; s4a, generating a single-layer polygonal projection space torsion surface reticulated shell structure through a multi-section line connection plug-in unit based on the grid points; the geometric parameters in the step S1a comprise the radius and the edge number of the bottom polygon, the height of the center vertex and the height of the edge vertex, and the setting method of the geometric parameters comprises the following steps: generating a bottom polygon by using a polygon plug-in, and setting parameters of the radius and the edge number of the bottom polygon through an input plug-in so as to control the shape of the polygon; obtaining a polygon center point, and obtaining the height of a center vertex by using a generating point plug-in and assigning a value to a Z coordinate; and parameterizing and adjusting the height of the edge vertexes, wherein the projection of each edge vertex is the midpoint of the edge corresponding to the bottom polygon.
7. The method for parameterizing and modeling a polygonal projection space torsion surface reticulated shell based on Grasshopper as claimed in claim 6, wherein the step S2a is used for constructing a third type of polygonal projection space torsion surface with a folded plate surface at the edge, and specifically includes: S2.1a, generating a linear ridge line connecting the vertex of the side part and the corner point and the center vertex of the bottom polygon; And S2.2a, generating an edge folded plate surface by using the adjacent linear ridge lines and the corresponding bottom edge lines as tracks and sweeping the plug-in units by double tracks.
8. The method for parametric modeling of a polygonal projection space torsion curved surface reticulated shell based on Grasshopper as claimed in claim 6, wherein the curved surface constructed in the step S2a is a fourth type of edge cylinder, and the step S2 specifically includes: S2.1a', generating a central curved surface ridge line frame and an edge curved surface ridge line frame which are formed by arc ridge lines according to the central vertexes, the edge vertexes and the corner points of the bottom polygon; S2.2a', for an edge area obtained by connecting corner points of an edge vertex and a bottom polygon, two adjacent arc ridge lines and bottom edge lines are taken as tracks, a partial cylindrical surface is generated by a double-track sweep plug-in unit, and a complete edge cylindrical surface is obtained by an array plug-in unit; and for a central area obtained by connecting the central vertexes with the edge vertexes and the corner points of the bottom polygon, taking two central arc ridgeline and two edge arc ridgeline as boundaries, generating a local central curved surface through four-sided faceting operation, and obtaining a complete central torsion curved surface through an array plug-in.
9. The method for parameterizing and modeling a polygonal projection space torsion surface reticulated shell based on Grasshopper as defined in any one of claims 7 or 8, further comprising a step S5a of generating a truss type double-layer reticulated shell, wherein the step is to move the nodes of the single-layer reticulated shell to obtain nodes of a lower chord layer, and connect the nodes of the upper chord layer and the lower chord layer to form the double-layer reticulated shell, and specifically comprises the following steps: S5.1a, taking the node of the single-layer net shell as an upper chord layer node, and generating a lower chord layer node by shifting along the normal direction or the vertical direction; s5.2a, connecting the lower chord layer nodes to form a lower chord; And S5.3a, connecting the corresponding upper chord layer node with the lower chord layer node to form a web member system, wherein the web member system comprises a diagonal web member generated by pairing and connecting the upper chord node and the lower chord node with different parity.
10. The method for parameterizing and modeling a polygonal projection space torsion surface reticulated shell based on Grasshopper as defined in any one of claims 7 or 8, further comprising a step S5a' of generating a conical double-layer reticulated shell, wherein the lower chord layer node is obtained according to the movement of the single-layer reticulated shell node, and the step of connecting the upper chord layer node and the lower chord layer node to form the double-layer reticulated shell specifically comprises the following steps: s5.1a'. Taking the node of the single-layer net shell as an upper chord node, and generating a lower chord node along the normal offset of the upper chord surface of each grid unit; s5.2a', connecting the lower chord nodes to form a lower chord; And S5.3a', wherein each upper chord node is connected with the corresponding lower chord node and the adjacent lower chord node to form a triangular cone-shaped or quadrangular cone-shaped web member system.

Description

Grasshopper-based polygonal projection space torsion surface reticulated shell parametric modeling method Technical Field The invention relates to the technical field of auxiliary building design, in particular to a Grasshopper-based polygonal projection space torsion surface reticulated shell parameterization modeling method. Background In the field of large-span space structures, the reticulated shell structure has become the preferred form of the marked building due to the excellent mechanical properties and rich modeling capability. With the continuous improvement of aesthetic and functional requirements of buildings, the space torsion surface reticulated shell structure with free modeling and complex shape is increasingly widely applied. Such structures often involve complex geometric logic and spatial topological relationships. Currently, modeling such complex reticulated shell structures relies primarily on traditional three-dimensional modeling software, such as Rhinoceros, CATIA, and the like. The designer needs to manually position key control points, generate a space curved surface, and then grid divide and connect with the rod pieces. The method has the defects that when any design change is encountered, such as adjustment of polygon edge number, curved surface curvature or reticulated shell thickness, complicated manual modification is needed from beginning, the design period is long, the method cannot adapt to the requirement of rapid iteration, and for complex combination forms such as edge folded plates, edge cylindrical surfaces and the like which need smooth transition with a central torsion curved surface, the traditional method lacks systematic generation logic, is difficult to directly and accurately convert into a structural calculation model, and the modeling result may be unsatisfactory. In order to improve the structural form of the space curved surface net shell and improve the modeling efficiency, a polygonal projection torsion curved surface net shell parameterization modeling method based on Grasshopper is provided. Disclosure of Invention In order to overcome the problems in the prior art, the invention aims to provide a Grasshopper-based polygonal projection space torsion surface reticulated shell parametric modeling method which is used for solving the technical problems of difficult modeling, low modeling efficiency and low recycling rate of the existing space reticulated shell structure with complex modeling. In order to achieve the above purpose, the invention provides a Grasshopper-based polygonal projection space torsion curved surface reticulated shell parametric modeling method, which comprises the following steps: step S1, setting geometric parameters of a net shell model in a Grasshopper platform through an input plug-in unit to obtain a corresponding space curved net shell surface projection surface; S2, connecting the vertexes of the projection surface to generate a ridge line forming a curved surface of the reticulated shell, and constructing a polygonal projection space torsion curved surface through curved surface generation operation based on the ridge line; step S3, performing grid division on the space torsion surface by using an isoparametric method or a mapping method to generate grid points; S4, generating a single-layer polygonal projection space torsion surface reticulated shell structure through a multi-section line connection plug-in unit based on the grid points; The geometric parameters in the step S1 comprise the radius and the edge number of the bottom polygon, the height of the center vertex and the extension length and the height of the external corner point, and the setting method of the geometric parameters comprises the following steps: generating a bottom polygon by using a polygon plug-in, and setting parameters of the radius and the edge number of the bottom polygon through an input plug-in so as to control the shape of the polygon; The height of the central vertex is parametrically adjusted by using a generating point plug-in and assigning a value to the Z coordinate; The line segment formed by connecting the polygon center point and the polygon edge inner middle point is extended outwards by utilizing the generated extension line segment plug-in, and the extension length parameter is used for controlling the projection plane position of the external corner point; and the generating point plug-in is used again, and the space height of the external corner is parameterized and adjusted by assigning a value to the Z coordinate of the external corner. Optionally, the step S2 is configured to construct a first type of polygonal projection space torsion surface, and specifically includes: s2.1, generating a ridge line connecting the central vertex with the polygon corner point and the external corner point; and S2.2, generating a local space torsion curved surface based on the ridge line, and forming a complete first polygonal projection space t