Some embodiments of the invention provide a Local Preferred Direction
(LPD) wiring model for use with one or more EDA tools (such as placing,
routing, etc). An LPD wiring model allows at least one wiring layer to
have a set of regions that each have a different preferred direction than
the particular wiring layer. In addition, each region has a local
preferred direction that differs from the local preferred direction of at
least one other region in the set. Furthermore, at least two regions have
two different polygonal shapes and no region in the set encompasses
another region in the set. Some embodiments also provide a Graphical User
Interface (GUI) that facilitates a visual presentation of an LPD design
layout and provides tools to create and manipulate LPD regions in a
design layout.