The pretreatment(DCL) technology in parametric design based on Auto CAD 12.0 was expounded and its principle and the realization process was analyzed.

• 以普通挤出机螺杆的参数化程序设计为例，阐述在AutoCAD12.；0环境下进行二次开发的前处理技术，并对其原理和实现过程进行了分析。