Drawing Annotations Research Articles

Knowledge-based automatic allocation of cad drawing annotation to wireframe iges models of 2 1/2-D prismatic parts

A knowledge-based Prolog program is presented that interprets the annotation information of a CAD drawing in terms of geometry primitives derived from the wireframe model used to create the drawing. The knowledge base consists of rules for recognising drawing symbols, parsing annotation text, identifying the connecting elements between text and geometry, suggesting geometry primitives to be sought for different annotation entities, and defining geometric connectivity relations. This enables the knowledge base to be incrementally developed to cater for more cases. So far, size tolerances, surface finish and some drawing notes are dealt with by the system. All the information needed as input is obtained from the component's IGES file.