Abstract
In a process of architectural design, designers refer "design rules" that exist among building elements : shapes, connections, and positions are some of them. However, most CAD do not have convenient utilities to handle them, but ask designers to manipulate graphic entities that indicate outlines of building elements, referring rule based operations in his image. For the purpose of developing an intelligent CAD in which designers can manipulate design rules and in which graphic entities can be automatically edited once design change occurs, this paper has proposed an object oriented system that handles three types of "relational information" that correspond to design rules.
