Bob, Do a search thru the archives of the forum - I asked the same question earlier this year (March) and there are many good responses. We are switching to Allegro and I needed to establish a library standard. http://www.freelists.org/archives/icu-pcb-forum/ Hth, Dave > > From: Bob McCreight <bobmccr8@xxxxxxxxx> > Date: 2007/07/19 Thu AM 08:50:30 CDT > To: icu-pcb-forum@xxxxxxxxxxxxx > Subject: [PCB_FORUM] Planes: Negative vs. Positive? > > The design team I work with is split one which to use, negative or positive > planes. > What are the pros and cons of each? What do most people prefer to work with? > We are currently using 15.5.1 but evaluating 16.x for possible future > migration. > > Thanks for your feedback. > > Bob McCreight, C.I.D. > > > > Dave Schaefer dave.schaefer@xxxxxxx ----------------------------------------------------------- To subscribe/unsubscribe: Send a message to icu-pcb-forum-request@xxxxxxxxxxxxx with a subject of subscribe or unsubscribe To view the archives of this list go to http://www.freelists.org/archives/icu-pcb-forum/ Problems or Questions: Send an email to icu-pcb-forum-admins@xxxxxxxxxxxxx -----------------------------------------------------------