An approach is provided for enabling simulation of photomask contour shapes, performing verification on the simulated photomask shapes, and correcting errors in OPC correction or bad fracturing methods to perform photomask proximity correction in real time before physically writing of the photomask. Embodiments include performing optical proximity correction of a photomask of a semiconductor layout to generate a corrected photomask, simulating the corrected photomask to generate one or more simulated contour shapes within a simulated photomask, verifying the simulated contour shapes to determine errors associated with the simulated photomask, and correcting the errors in the simulated contour shapes of the simulated photomask to generate a final photomask.