Re: gEDA-user: Outputting negative plane layers from pcb?

[DJ Delorie <dj@delorie.com>]

PCB doesn't do ground planes the same way as other packages, we
actually draw the copper, and anti-draw the reliefs (negative layers
have you draw the reliefs).  Planes are no different than any other
polygon on any other layer (you created your plan by drawing a big
rectangle, yes?), so if they can do regular layers, PCB planes should
work too.

In theory, if they ask "which layers are planes?" you can answer
"none" and it should still give you what you expect.

Having said that, it's probably a good idea to send them the gerbers
with a note saying that we do planes different, and please check to
make sure they'll come out right.  When you find out, let us know, and
we'll either (1) fix it if we can, or (2) note that we do the right
thing ;-)

We do, however, use negative plots for solder masks.