||In Korea, construction industries have started to recognizethe importance of the conceptual model of building objectsto integrate various information from different views on aproject. An object-oriented model was proposed andimplemented partially. The implemented system of the modelat this stage aims at the automatic generation of twodimensional drawings from three dimensional objects eventhough the objects defined in the system carry moreinformation than just geometric properties. Informationregarding structural analysis, construction planning, andscheduling is represented in the model. It was concludedthat three separate modules need to be developed to coverthe most popular structural types of current projects :reinforced concrete, steel, and shear wall. However, thesemodules share many objects which represent architecturalcomponents like non-bearing walls, openings, stairs, rooms,doors and windows. To be a flexible design tool, an inputmechanism for a model should facilitate a three dimensionalCAD system. Once objects are defined and placed through auser interface in a CAD environment, the system createsobjects which in turn are checked for consistency. Thereare access functions to retrieve data for other applicationprograms.