QUERY-BY-POINTING INTERFACE OF THE DATA STRUCTURE FOR COMPUTER GRAPHICS NC PROGRAMMING.

Query-by-Pointing (QBP) is a kind of graphic interface between the user and the geometry model of parts, which enables the user to query information about the element stored in the model by pointing at its position on the screen. The QBP algorithms and their data structures are synthesized and generalized. A new data structure and its QBP interface are put forward, to support the representation and query of 3D parts. This paper's geometric hit-detecting algorithm of elements combines the advantages of ray-surface-intersection method and the hit-detecting procedure of segment picking. The characteristics of the new algorithm are described.