FLOWTRAN and PROCESS are engineering design packages which simulate the steady state operation of units commonly used in the chemical and petroleum industries. Given a rigorously structured data input file, these packages calculate stream properties (flow rate, composition, etc.) and unit design variables (distillation column size, pump rpm, etc.).FLOW.CPL has been developed to provide a graphical interface that will generate a FLOWTRAN compatible input file using the MEDUSA CAD system. The CAD model is built by interactively abstracting elements (representing unit operations) from a symbol library and placing them on a MEDUSA drawing sheet. The connectivity between the unit operations is provided by the user simply by connecting inputs to outputs. Additional stream information (temperature, pressure, composition, etc.) is provided by using associative blocks called clumps. After the user drawing stage has been completed, FLOW.CPL scans the sheet to remove the information and generate a FLOWTRAN compatible data input file.The interface is expected to substantially improve initial design productivity as well as provide diagnostic and modification support for an existing chemical process.