You can also use the built-in Offset Tool on two or move preselected edges and type in an amount to offset a copy OR offset all of the edges of a selected face by an amount. There is also a double-line tool [dline] by Didier Bur / Jim Foltz, it's available from the crai depot http://rhin.crai.archi.fr/rld/plugin_details.php?id=804 Or in this post here http://forums.sketchucation.com/viewtopic.php?p=297720#p297720