Automated Dimensioning Method of Engineering Drawings for Mechanical Products Based on Curve Chain

An automated method based on the curve chain was proposed for dimensioning of engineering drawings for the mechanical products. According to the internal relation between the features of 3D model feature and elements of 2D drawing, the curve chain was established to reflect the geometric topological structure between the elements. It divides the dimensions into the absolute dimensions within the cure chain and the relative dimensions between the curve chains. The parallel and lengthy relationship between the drawing elements of the constructed X and Y parallel matrix was solved to remove redundant elements in the curve chain and labeled the absolute dimensions of the remaining valid elements. The average minimum weight coefficient was introduced to judge the dependence on the relative dimensions between curve chains. Through the analysis of the overlap between the circular rectangular areas, including all the absolute dimensions of the curve chains, overlapping curve chains were merged, and their dimensions were rearranged to avoid the cross interference between them. The method was seamlessly integrated into the drafting module of product design software NX, and it developed an automated dimensioning system. The examples show that the system has excellent interactivity and robustness in the dimensioning of product engineering drawings. The dimension information is complete, accurate and reliable.