The present disclosure provides one embodiment of an integrated circuit (IC) method. The method includes receiving an IC design layout having a pattern, assigning target points to segments of the pattern, and producing first a simulated contour of the pattern based on the assigned target points. The method further includes reassigning the target points to the segments of the pattern based on the first simulated contour of the pattern; producing a second simulated contour of the pattern based on the reassigned target points, and after producing the second simulated contour of the pattern, producing a modified IC design layout.