A Knowledge-Navigation System for Dimensional Metrology Volume 107 Number 2 March–April.pdf

Volume 107, Number 2, March–April 2002 Journal of Research of the National Institute of Standards and Technology [J. Res. Natl. Inst. Stand. Technol. 107, 193–205 (2002)] A Knowledge-Navigation System for Dimensional Metrology Volume 107 Number 2 March–April 2002 Howard T. Moncarz National Institute of Standards and Technology, Gaithersburg, MD 20899-8200 howard.moncarz@ Geometric dimensioning and tolerancing (GDT) is a method to specify the di- mensions and form of a part so that it will meet its design intent. GDT is difficult to master for two main reasons. First, it is based on complex 3D geometric entities and relationships. Second, the geometry is associated with a large, diverse knowl- edge base of dimensional metrology with many interconnections. This paper de- scribes an approach to create a dimensional metrology knowledge base that is orga- nized around a set of key concepts and to represent those concepts as virtual ob- jects that can be navigated with interactive, computer visualization techniques to ac- cess the associated knowledge. The ap- proach can enable several applications. First is the application to convey the defini- tion and meaning of GDT over a broad range of tolerance types. Second is the ap- plication to provide a visualization of di- mensional metrology knowledge within a control hierarchy of the inspection pro- cess. Third is the application to show the coverage of interoperability standards to enable industry to make decisions on stan- dards development and harmonization ef- forts. A prototype system has been imple- mented to demonstrate the principles involved in the approach. Key words: dimensioning and tolerancing; dimensional metrology; knowledge navi- gation; manufacturing training; VRML. Accepted: March 1, 2002 Available online: /jres 1. Problem Statement Dimensional metrology is the science of measure- ment based on length. To fully understand the subject, a broad knowledge base that includes the measurement process, the languag