Abstract: A computer system for simulating a user-specified automated manufacturing and/or materials handling facility. The system includes a CPU interconnected to an operator terminal through which information is entered by a designer who specifies various computer-controlled components and operating parameters which are to be tested in a particular design. The system designer is provided with a catalog of user-oriented language descriptions of available components from which he can select the various components and their operating parameters. The user-oriented language descriptions entered by the system designer are used by the CPU to automatically create an operational prototype model for each selected component, which is then compiled by the CPU into a corresponding series of general purpose simulation statements which are processed to determine the simulated operation of the automated manufacturing and/or materials handling facility design.