Analog simulation often requires many iterative steps to fine-tune a design. The more the CAD tools reflect this need, the more efficient a designer's time will be. The complexity of frequently used operations is directly proportional to the time it takes to refine a design. These operations are creating a netlist, modifying the netlist to reflect the optical shrink in processing (a common way to cost reduce a design without creating new design cell libraries), setting up scripts, plotting, and more. Integration of tools has been the goal of CAD.

This paper describes how a well-designed command tool such as Tcl can be used to integrate existing tools and shorten design time.