To produce a graphically oriented interactive interface to an engineering system, some method of displaying and interacting with both geographic, iconic, and textual information about an engineering domain is needed. However, generating effective requirements for such a system is not a completely straightforward process. There are many aspects of the interactive process for which an optimal or even adequate specification is not currently possible. This is because of the inherent complexity of completely describing an image compounded from several independent parts, each of which can change as a function of the stage and content of the interaction. An alternative to the approach of attempting an a priori specification of a graphics interface is to build a systems engineering and prototyping tool that would allow the simulation of such an interface. With such a tool, a graphics interface could be evaluated during the requirements generation stage and the requirements tailored as needed. Moreover, the simulation itself would provide a set of explicit requirements that are inherently implementable. A number of characteristics are desirable in such a tool. These include device independence, so that users are not tied to specific hardware, a scripting facility, so that user written scripts can drive the interface, parameterized graphics descriptions, so that graphics objects may be created and stored in a invocation independent fashion, and a database interface, so that data can be extracted and displayed from an application specific database. In addition, provision must be made for the different styles of interface design so that demands for windowing and other complex features can be accommodated. A demonstration of portions of such a tool has been built and an effort is underway to complete implementation. At the center of GRAPE is an abstract machine that carries out its abstract operations. Six high level languages, a Script Language (SL), a Command Definition Language (CDL), an Object Description Language (ODL), a Menu Definition Language (MDL), a Form and Table Definition Language (FTDL), and a Device Interface Language (DIL), are interpreted into operations of this abstract machine. Along with window and file managers, these languages provide the facility for an interface designer to specify command structures, graphics objects, menu structures and content, form and table layouts, and a script that ties these elements together into a simulated interface. The simulation will run on any device specifiable in the Device Interface Language. The output of the abstract machine running a script is a simulation of the complete interface, including i/o, although response time is dependent on the hardware utilized.