A Multilevel Modeling Structure for Interactive Graphic Design

In the past, a common data structure, or model, has been used for all phases of a computer graphics design system. This has meant that the model used during conversational interaction was the same as the model used in the subsequent analysis operations, usually resulting in poor overall performance. This paper suggests the use of separate models for each phase, providing a general model for the conversational drawing phase which is suitable as a front end in many different application areas. Described are data structures and programs for both phases: a conversational display image manipulation program (DIM) and its interconnections with an existing analysis application program (IBM 1130 Continuous System Modeling Program). Examples of the use of this particular multilevel modeling design facility are included.