Abstract: This disclosure describes systems, methods, and devices related to optical proximity corrections to an integrated circuit photomask. A method may include identifying a first contour of a first adjacent polygon of a photomask predicted for a first polygon of an integrated circuit, the first contour excluding a first corner formed by a first edge and a second edge of the first polygon; identifying a second contour of a second adjacent polygon of a photomask predicted for a second polygon of the integrated circuit, the second contour excluding a second corner formed by a third edge and a fourth edge of the second polygon; generating a fast contour prediction based on corner rounding associated with the first contour and the second contour; and generating, based on the fast contour prediction, a minimum distance between the first contour and the second contour, the minimum distance associated with the optical proximity corrections.