一个基于模式匹配的参数化尺寸标注系统

文章讨论了一个新的参数化尺寸标注系统的实现原理、关键技术和设计方法。该系统在以下几个方面取得明显进展，其一，基于AutoCAD的尺寸标注功能及存储格式，设计了新的通用、完整、可靠的尺寸标注系统，为AutoCAD增添了新的标注功能，使其能够准确地标注国家机械制图标准所规定的尺寸标注模式。其二，归纳了AutoCAD和国家标准的各种尺寸标注模式，借助于模式匹配及其推理，自动标注不同类型的尺寸标注，实现了智能化尺寸标注功能。其三，尺寸标注变量及其约束表达式功能，在参数化模型图的参数编辑、尺寸驱动和尺寸标注图素自动生成方面显示出极大的效率。

A Parameterization Dimension System Based on Pattern Matching

This paper deals with the implementation issues and designing method of a new parameterization dimension system. Firstly, based on the dimensioning function and stored format of AutoCAD, a perfectly reliable dimension system that can be generally applied is designed, which adds new functions to AutoCAD and enables it to accurately dimension all the modes prescrihed by the national standards for mechanic charting. Secondly, various dimensioning modes of AutoCAD in line with the national standards are summed up.And with the help of pattern matching and adequate reasoning, the system can automatically dimension models of various types and intelligent dimensioning is thus realized. Thirdly, the varibles and restricted expressing function turn out to be greatly effective in parameterized models charting in its parametric editing, dimension- driven and automatic generating of dimensioning picture elements.