gEDA-user: generating a solder paste layer and xy placement data in PCB

["Joel N. Weber II" <jwgeda@xxxxxxxxxxxxx>]

I'm about to start working on a board design that will use a mixture
of thru hole and surface mount parts, and I'm planning to have
Screaming Circuits assemble it.  Screaming Circuits wants a gerber
file with the solder paste layer, that matches the surface mount pad
copper area exactly.  (I'm not sure whether they also want paste on
the thru hole pads, and have sent them email asking.)

(I avoided this problem last time around by doing a thru hole only
design, where it is apparently most cost effective to rely on
hand-soldering, and so they didn't need a solder paste file; and for
whatever it's worth, using pcb and pcbexpress.com and
screamingcircuits.com appears to have produced the results I wanted.
However, I believe on this next board I'm going to want to use a part
that's available surface mount only, and this next board is going to
be complicated enough that eating the automation setup fees will
probably save money in the long run.)

I'm guessing that I may want to use layer groups somehow, but I'm not
really sure how to do that.  It seems like the approach would be to
put the pads on one layer and the component side traces on another,
and then generate one gerber that includes both layers, and another
that includes only the SMT pads.

Or the other approach would be to just use one of the layers that's
intended to be an inner copper layer (I expect I'll probably be able
to do make this design use a two layer board), and make the SMT pads
appear on two both the component copper layer, and on the paste layer,
and this would probably be simpler in that I wouldn't have to think
about how to make layer groups work.  I imagine I could probably just
draw the pads on the component layer, save the file, and then use
emacs to copy the pads to the other layer.  (Actually, I'm likely to
enter the precise dimensions in emacs after drawing a few pads in pcb
so that I can see what the file format is supposed to be.)

I also need to figure out how to make the xy placement file actually
have data.  When I created components as board layouts, saved them,
and then used the load layout to paste buffer command, I ended up with
empty xy placement and bom files.