Method for separating topological face based on triangular patch model

Abstract

The invention relates to a method for separating a topological face based on a triangular patch model. The method comprises the steps of: 1) carrying out data pre-processing on the triangular patches in the triangular patch model; 2) decomposing a topological face from the triangular patch model by the combination of the triangular patches; 3) building basic geometric information of the topological face; and 4) judging whether all topological faces are decomposed from all triangular patches in the triangular patch model; if not, decomposing the topological faces from all triangular patches in the triangular patch model and returning to the step 2); or else, finishing the separating method.

Description

technical field [0001] The present invention relates to CAD modeling technology, more specifically, relates to a topological surface separation method based on a triangular surface model. Background technique [0002] In the prior art, it is a common method in 3D modeling to represent the data model of the surface of a CAD entity with many spatial triangular facets. This method discretizes the CAD surface into triangular patches. There are different triangle meshes for different precisions. Usually, each triangle facet is represented by 4 data items, that is, the coordinates of the three vertices of the triangle and the external normal vector of the triangle facet. The entire CAD entity data model is represented by a collection of multiple triangle faces. The data structure is simple, and Independent of the CAD system used. [0003] However, this representation method only lists the geometric information of all triangles constituting the surface of the solid in an unorder...

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Problems solved by technology

[0003] However, this representation method only lists the geometric information of all the triangles that make up the surface of the solid in an unordered manner, and does not contain any topological adjacent information between triangles.

Therefore, when the solid model is reconstructed with the file generated by the triangle patch representation method, the following two problems will be encountered: First, because the imported 3D solid model is a triangulated model, the topological information is scarce, and only the constituent model can be known. Points and triangular patch information, but can not know the topological information of each surface of the model; second, the number of triangular patches that make up the part is too large, a simple sphere model is about 5000 triangular patches, and the There is a lot of redundant data, and even many errors and defects

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