Aspects of the invention relate to techniques for mask rule checking based on curvature information. The curvature information comprises convex curvature information and concave curvature information. The convex curvature information for a vertex of a mask feature may comprise a convex curvature value derived based on the size of a circle that passes through the vertex, is tangent to an edge and does not cross any other edges. The concave curvature information for the vertex may comprise a concave curvature value derived based on the size of a circle that is tangent to two edges that form the vertex and does not cross any other edges, and of which distance from the vertex measured from the nearest point is no more than a predetermined number. The generated curvature information is compared with threshold curvature information to determine mask rule violations.