1. A method of performing optical proximity correction (OPC) on a target design for a lithographic process, the method comprising: obtaining an optical system heating model that accounts for effects of optical system heating in the lithographic process; obtaining a set of process window conditions associated with the lithographic process; determining one or more pattern failures across the set of process window conditions using the optical system heating model; performing, by a hardware computer system, OPC on the target design based on the determined one or more pattern failures; and outputting an electronic representation of the corrected target design for creating the pattern as provided by a patterning device of the lithographic process.