Spacing query method for triangular gridding curve model

Abstract

The invention provides a method for searching space of a triangular mesh surface model. The method comprises the following steps: first, triangular patch data expressing product surface information and a node in an index structure are both expressed into corresponding four-dimensional point objects; the four-dimensional point objects are subject to space clustering partition by selecting an insert position, realizing node split by four-dimensional clustering method, adjusting an axial bounding box of the node in the index structure and the corresponding four-dimensional point subjects, and other steps; and space clustering partition of the triangular patch in the triangular mesh surface is realized so as to establish the index structure of the triangular mesh surface model. Based on the structure, efficiency of various space searching operations of the discrete triangular mesh surface model can be improved, the speed for processing reverse engineering data of a product can be effectively improved, and stability and accuracy of a processing result is ensured.

Description

technical field [0001] The invention provides a space query method for a triangular grid surface model, which belongs to the technical field of product reverse engineering. Background technique [0002] In product reverse engineering, triangular mesh surfaces can quickly and flexibly reconstruct complex product models. In order to accurately express product information, triangular mesh surface model data is characterized by a large amount of data, high spatial complexity, and lack of topological relationships between data The establishment of a stable and efficient index structure for the triangular mesh surface model is essential for improving the simplification and encryption of the triangular mesh surface model, solving the intersection line of the triangular mesh surface model, and generating NC machining tool paths based on the triangular mesh surface model. efficiency is of great significance. [0003] Retrieval of existing technical literature found that Wang Lei et ...

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Problems solved by technology

[0003] Retrieval of existing technical literature found that Wang Lei et al. published the paper "Ordered Adjacency Vertex Table Data Structure of Subdivision Surface" in the academic journal "Computer Application Research" 2004, 9, P95-97, according to the triangular mesh surface model For the vertex information and edge information of the discrete triangular face, establish an adjacency table for each triangular face, and store the triangular face information that is topologically adjacent to the triangular face in the triangular face adjacency table, which is only suitable for fast The local neighborhood data of the triangular mesh surface model cannot meet the high efficiency requirements of other spatial queries in reverse engineering

[0004] Zhou Hai used the spatial octree as the index structure of the triangular mesh surface model in his doctoral dissertation "Research on Subdivision Surface Modeling Technology". The node insertion of the octree establishes the index structure of the triangular mesh surface model. This index method is only suitable for establishing the index structure of the triangular mesh surface model evenly distributed in the space. In addition, the center of the bounding box of the triangle patch is used instead of the triangle The index structure of the surface is established, and the triangular surface information is lost. The spatial query based on the index structure is inaccurate, and the triangular surface is often missed.

[0005] Wang Zhanli used a large bounding box to enclose the triangular mesh surface model in his doctoral dissertation "Research on NC Machining Simulation Technology Oriented to Virtual Manufacturing". Each part is surrounded by a bounding box, and then each bounding box is recursively divided until a bounding box only contains a triangular patch, and an unbalanced binary tree index structure of the triangular mesh surface model is established, based on which the structure is improved. The efficiency of various query operations of the triangular mesh surface model is improved. Since the structure is an unbalanced binary tree, it is only suitable for the triangular mesh surface model with evenly distributed triangular patch data. When the triangular mesh surface model data is unevenly distributed , it is easy to have too many layers in a certain branch of the tree, which will lead to a sharp deterioration of the data structure and seriously affect the efficiency of spatial query

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