Research On The Algorithm For Analysis Of Engineering Drawing Computer Alignment

With the rapid development of computer aided design (CAD) technology, the computer vector engineering drawings have gradually replaced the paper engineering drawings. As the main carrier of express design information and manufacture information, efficient graphic retrieval and matching plays an increasingly important role in the production activities from the large number of digital engineering drawings.In engineering drawings, the main carrier of information is the shapes of the graphics and the spatial relationships between them. According to the features of engineering drawings, preprocessing the engineering drawings is the first step, which mainly includes the contours’merge and interrupt. The second step is to identify and extract the smallest closed wireframe graphics, and based on the spatial relationships between them, a topology tree is established to describe the structure of engineering drawings. Finally, by calculating the similarity of the topology tree and the smallest graphics, we can carry out the similarity comparison between two engineering drawings.In this paper, by combining Visual Studio C++programming language with AutoCAD secondary development interface tool ObjectARX, an experimental software system is initially established to analyse the similarity of two simple engineering drawing graphics, which lays a foundation for graphic retrieval.