1. A method of defining a global route for a net in a region of a layout, wherein each net has a set of routable elements, the method comprising: a) partitioning the region into a plurality of rectangular sub-regions; b) identifying a set of sub-regions that contain the routable elements of the net; c) defining a global route that connects the identified sub-regions, wherein the global route includes at least one non-Manhattan edge that crosses a boundary between two sub-regions at a non-vertex location.