1. A computer-implemented method of determining a lithographic tool set point for a lithographic process, the method comprising: providing a model of a production lithographic process including simulations of printed shapes; analyzing the model of the production lithographic process to determine whether a set of structures on a production mask used in the production lithographic process to create the printed shapes will fail under a plurality of set points; determining an operating region of set points where the set of structures on the production mask does not fail; and establishing a set point location within the operating region based upon a set point selection function.