The use of annotation in design representation

This paper describes the use of annotation in computer-aided design (CAD) as a mechanism for recording the viewpoints of engineering specialists concerning the semantic interpretation of elements of CAD models, and then briefly presents suggestions on how annotation of text documents may be analogous to that of CAD models. Annotation, applied through markup of the elements of boundary representation solids, allows semantic information from multiple viewpoints to be recorded in CAD part models and then used for subsequent design evaluation. Markup may be introduced into a model in different ways. Three modes are described, based on approaches to feature-based design such as design-by-features and feature recognition. These modes consider markup incorporated in the course of model creation, post-hoc markup from different perspectives, and automated markup based on the model contents, including existing markup as appropriate. Similar modes may be identified in the annotation of text documents, and similar life-cycles may be envisaged in the development of annotation in both text and CAD models.