A layer-cut multi-connected domain construction method based on adjacency topological association of geometric mesh model

Abstract

The invention discloses a layered machining multi-connected-domain construction method of adjacency topological correlation of a geometric network model. The method comprises: a global numerical value calculation threshold is set; a convex bounding box of a geometric grid model point cloud is solved; coordinate transformation is carried out; a layered machining plane set is built by using a layered direction as a layered machining plane increasing direction; pre-blocking of all grid patches is carried out and an index link table storage intersected grid patch set is constructed; an adjacency topological lined table is calculated, a grid patch ring is obtained, and a common adjacent side is obtained by calculation; and intersection points of the common adjacent side are obtained and the layered machining planes and are processed by ordering to obtain a ring, and a cross contour of a connected domain of all layered machining planes is obtained. According to the method disclosed by the invention, pre-blocking is carried out on the grid patches of the geometric grid model, so that the determination frequency of relative positions of the layer machining planes and the grid patches can be reduced; because of association of the adjacency topological relation of the grid patches, synchronous ordered ring forming of intersection point segments is realized, so that an intersection forming problem of composite rings with singular points can be solved; and high robustness and high efficiency of the complicated geometric grid model as well as geometric layered machining with balanced precision can be realized.

Description

technical field [0001] The invention relates to a method for processing geometric models of complex mechanical parts in the field of advanced manufacturing technology, in particular to a method for constructing layer-cut multi-connected domains of geometric grid models in the field of additive manufacturing. Background technique [0002] 3D printing (3D Printing) can realize rapid prototyping (RP), which is to obtain parts by adding materials layer by layer, and can directly generate part models from CAD solid data geometric models. Complex cavity molds, biomedicine, and engraved curved surfaces are increasingly widely used. In the rapid prototyping process, layering the CAD geometric model of the part is the key technology. Layer processing is to use a series of slice planes to intersect with the data model of the three-dimensional entity to obtain the two-dimensional cross-sectional profile information of each layer, so as to obtain the connected domain in the cross-secti...

AI Technical Summary

Problems solved by technology

The 3D part format contains topological information, which has the advantages of high precision, but large storage space, low calculation efficiency, and poor commonality limit the wide application of 3D printing.

When intersecting a triangle patch with a slice plane, it is necessary to traverse all the patches. A complex part model often has tens of thousands or even millions of patches, which will be very time-consuming

[0004] However, these methods still have some limitations, especially in the layered slicing of shapes with complex and changeable inner and outer surfaces, which have problems in both efficiency and accuracy

Existing slicing commercial software is difficult to solve the problem that the shape of the two-dimensional section contains singular points, and the contour information is lost at the singular points of the cross-sectional shape, and it is difficult to completely express the actual cross-sectional contour of the complex model

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