Abstract: Disclosed is a computer system for substantially automating the design of a building control system. The system comprises a processor for processing data stored in a data base, the data being related to a building control system design and comprising both graphic and alpha-numeric information. The processor comprises the ability to call up on a display an initial drawing related to a building control system element. The initial drawing comprises graphic and related alpha-numeric information including an identifier associated with the element and a prompt guiding modification of the initial drawing. The processor also includes the ability to create a modified drawing by incorporating changes into the initial drawing, the modified drawing being related to a building control system design.