Surface Feature Type Recognition Method Based on Feature Line and Topological Relationship

Abstract

The invention discloses a curved surface characteristic identification method based on a characteristic line and a topological relation. According to the method, the curved surface type is judged from the characteristic line, a curvature area concave and convex area and the topological position relation. The method comprises the following steps: firstly, identifying a curved surface area characteristic line comprising a boundary line and an internal key characteristic line; secondly, analyzing the curvature characteristic of the curved surface area, and dividing the curved surface area into curvature area curved surface diagrams; thirdly, obtaining the characteristic line between the concave and convex areas; and finally, constructing the topological relation of the characteristic line and the curvature area curved surface, and identifying the curved surface characteristic type with a rule-based method and an evolutionary algorithm. The method is mainly characterized in that the characteristic main class is judged from the concavity and convexity in the boundary line and the curved surface, the corresponding shape characteristic is identified from the characteristic line and the topological position, and therefore the difficulty due to identification completely from the geometrical shape is avoided. The invention is applied to the free curved surface characteristic identification of a CAD (computer-aided design) model, the characteristic conversion of a product model and the design requirement on the appearance can be satisfied, and effective information support is provided for the applications, such as downstream analysis processing.

Description

technical field [0001] The invention belongs to the field of computer-aided design, and in particular relates to the definition, parametric representation and recognition of curved surface features in feature technology. Background technique [0002] The research on feature technology is gradually shifting from simple features to complex features, and from regular features to surface features. However, surface feature technology is still in its infancy, and there are still many problems to be solved. In terms of design feature recognition in surface models, due to the complexity and variety of free-form surface features and too many degrees of freedom, it is difficult to perform feature recognition as conveniently as regular features. In view of the existence of a large number of surface models, by using the feature line information and its topological relationship in the surface features, the automatic feature recognition of the surface model and the generation of feature m...

AI Technical Summary

Problems solved by technology

However, so far, the feature recognition technology is still in the recognition of regular features and a small number of simple free-form surface feature recognition. These recognition methods are difficult to extend to general free-form surface feature recognition.

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