Abstract: Feature modeling is the key technique in the new CAD system,it is the core technique of product model.This paper discusses semantic feature modeling based on cellular model.Feature Dependency Graph（FDG） is used in semantic feature modeling to preserve feature information and relations among all features in design process.On this basis,this paper analyses the method of modifying feature precedence dynamically according to the relations among features in the feature dependent graph to insure the availability of model modification.An example is introduced at last.

Key words: semantic feature modeling, cellular model, feature dependent graph, feature precedence

摘要： 特征造型技术是新一代CAD系统的关键技术,是产品模型技术的核心。该文讨论了以细胞元模型为基础的语义特征造型技术。在语义特征造型中用特征依赖图（FDG）的数据模型来保存和维护设计中的各种特征信息及其之间的关系,在此基础上分析了依据特征依赖图中特征间的关系动态修改特征优先级的方法,确保了模型修改的有效性。最后给出了一个实例。

关键词: 语义特征造型, 细胞元模型, 特征依赖图, 特征优先级