Based On The Step Standard Cad Product Data Exchange

STEP (Standard for the Exchange of Product Model Data), established by IS0,is an international standard for the computer-interpretable representation and exchange of product data. STEP referenced many existed data exchange standards, especially PDES, and is still under perfecting and expansion. As a unitive international standard, STEP is supported by many well-known CAD system.This thesis is based on the science and technology project of GANSU province — THE INTELLIGENT DATABASE SYSTEM OF MECHANICAL CAD, some topic are studied and investigated according to the content on data exchange and share.In the first place, the evolution of Product Data Exchange is briefly introduced. Then the structure of STEP, the ultimate goal of STEP and its developing policy are analyzed in detail. Its up-to-the-minute status of its progress and the introduction of STEP'S characteristic of contribution to National Industry Information Infrastrcture Protocol are also included.Secondly, the construct of SDAI is introduced. Then, the building of database based STEP is given out. The application protocol of STEP and Advanced_boundary_representation is introduced.Finally, the prototype system is build. The algorithm of attributed graph of SDAI is given out. The algorithm is used to read the information. The module used in restoring, managing, drawing about information is developed. The adding and drawing to tolerance information is implemented. The example is given out.