A method, program product and system is disclosed for performing optical proximity correction (OPC) wherein mask shapes are fragmented based on the effective image processing influence of neighboring shapes on the shape to be fragmented. Neighboring shapes are smoothed prior to determining their influence on the fragmentation of the shape of interest, where the amount of smoothing of a neighboring shape increases as the influence of the neighboring shape on the image process of the shape of interest decreases. A preferred embodiment includes the use of multiple regions of interactions (ROIs) around the shape of interest, and assigning a smoothing parameter to a given ROI that increases as the influence of shapes in that ROI decreases with respect to the shape to be fragmented. The invention provides for accurate OPC that is also efficient.