By studying the iges data exchange standard and analyzing iges files produced by the preprocessors of cad systems , comprehend basic line elements and basic face elements constituting parts and summarize the means to get data information of parts and assemblies . 2 通過對iges數據交換標準本身的研究,分析比較由cad系統的前處理器生成的iges文件,了解組成零件的基本線元和基本面元的實體類型,總結出從iges文件中提取零件和裝配體數據信息的方法。