We disclose a method for optimizing integrated circuit layout which comprises analyzing constraint relationship among objects in an initial layout; constructing local modifications to the constraint relationship; forming new constraint relationships by combining initial constraint relationships with their local modifications; and producing a new layout by implementing the new constraint relationships. Local modification to constraints provides a framework for bringing detailed local information into the design process in a highly automated manner, which can be applied to a wide range of situations. We disclose preferred embodiments on improving lithography printability, reducing defect susceptibility, and improving circuit performance such as reducing layout variability and leakage.