Abstract: Based on parametric and semantic feature CAD systems，changing values of parameters is one of the most common operations，which is often a trial-and-error process.According to allowable parameter values are not known to the user beforehand，authors present a solution for automatically determining the allowable range for the parameter values.Authors find some distance or angle constraints by analyzing the graph of topological constraints and then put them into geometric constraints.Next，authors use the decomposition to find critical parameter values for sub-problems.By solving one problem instance for each interval between two subsequent critical values，the exact parameter ranges are determined for which a solution exists.

摘要： 基于参数和语义特征的CAD系统，改变参数的值是最重要的操作，也通常是一种反复性的过程，针对适合的参数值对于用户来说提前是不知道的，提出一种新的方法用于自动侦测参数的适当的范围。先通过分析拓扑约束图，找到距离和角度约束，并将这些约束加入到其相应的几何约束中，然后通过分解找到子问题的临界参数值，再求解每个并列的参数区间内部的一个具体的实例，精确的参数范围就能够被确定。