Surface boundary recovery method of grid model

Abstract

The present invention relates to a surface boundary recovery method of a grid model. The basic thinking of the method comprises the steps of classifying the coplanar and same-direction surface sections according to the characteristics of the surface envelope surface sections of the grid model; then, analyzing the edge-edge adjacent relation of the coplanar and same-direction surface sections in the same plane to obtain the surface sections capable of forming each surface of the model; and then, for each surface, identifying and extracting the boundary edges of the surface sections, and connecting the boundary edges from head to tail to form a plurality of rings, and then extracting the vertexes of the rings to obtain the rings represented by point sequence; finally, distinguishing the inner and outer rings to obtain the contour boundaries of the model surfaces. The surface boundary recovery method of the present invention has the advantages of being wide in application range, rigorous in algorithm logic, good in geometric completeness and strong in practicality and reliability, etc., and can be used for the reverse obtaining of the grid model, or the works of needing the reverse solution to further modify and simply the model, analyze the engineering numerical values, redivide the grid, etc.

Description

technical field [0001] The invention belongs to the technical field of computer graphics, and relates to a surface boundary restoration method of a grid model, which can be used for inverse calculation of a geometric model and has important application value in the field of engineering numerical analysis. Background technique [0002] In engineering numerical analysis method, grid division is a very important work, and its application is very wide, including many fields such as geography, medicine and mechanics. Grid division technology is mainly divided into structured grid technology and unstructured grid technology. A structured grid means that all interior points within a grid area have the same adjacent cells, whereas an unstructured grid is the opposite, where interior points within a grid area do not have the same adjacent cells. Intuitively, structured meshes only contain quads or hexahedrons, whereas unstructured meshes consist of triangles and tetrahedra. [0003...

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Problems solved by technology

It can be seen that the existing research results have the following problems: (1) The research only focuses on triangular meshes with hinged vertices (called hinges when vertices are connected to vertices), but for quadrilateral meshes with hinged vertices, hybrid meshes of triangles and quadrilaterals, and The case of unhinged vertices is seldom studied, and the existing results are narrowly applicable; (2) The proposed algorithm needs to artificially set some parameters, such as radius, characteristic angle, etc., and the robustness of the algorithm is not high; (3) The algorithm only extracts or restores the boundary edges, but there is no research on how to organize the surface by the edges (such as outer rings, inner rings), and the existing research is not deep enough

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