Copper zone option to inhibit combines with other zones

[bjerre]

Patch to let the user explicitly allow or disallow combining of the current zone with other zones, in the fill zone options menu. The need came from a ground plane requiring two different clearances, one for a microprocessor part and one for a rf frontend part. (Other users might like the same feature for hosting high and low voltage circuits on the same plane ?). In both cases it is akward that the zones gets combined.
Please notice that the attached patch is only a proof of concept, there is no guarantee that it doesn't bite.

[bjerre (bjerre)]

The file ZoneMergeOption.patch was added: Made against svn rev 1949

[Stephen Eaton (seaton)]

bug originally imported from sourceforge.

Marking as triaged as patch attached so will let dev team decide if it can be closed.

[Martin Errenst (imp-d)]

Pcbnew will (tested with r4864) merge two zones from the same net WITHOUT a hint about different settings in the zones.
A quick fix would be to stop the merge process if the zones settings differ.

[Lorenzo Marcantonio (l-marcantonio)]

On Thu, May 15, 2014 at 05:50:17PM -0000, jean-pierre charras wrote:
> Patch to let the user explicitly allow or disallow combining of the current zone with other zones, in the fill zone options menu. The need came from a ground plane requiring two different clearances, one for a microprocessor part and one for a rf frontend part. (Other users might like the same feature for hosting high and low voltage circuits on the same plane ?). In both cases it is akward that the zones gets combined.

I fully agree with the Won't Fix classification.

The correct way to get this effect is to use different net for different
zones, so you get DRC support and can't route by accident in another
zone.

In fact if you need to have split planes (like an analog ground and
a digital ground) these are at different potential so they must be in
different nets.

Different net obviously gives separated zones

--
Lorenzo Marcantonio
Logos Srl

[Claus Bjerre (bjerre3)]

Just my 2 cents: I am perfectly happy with the won't fix status since time has shown
that I was pretty much the only one that didn't like the zone merging.

I would however like to comment on the split zones and different nets.
This is probably the first and most basic rule of mixing say analog and digital circuits.
From my experince with a spectrum analyser haunting signal to noise on an ADC then
seperate nets will indeed produce different (ground) potentials and unfortunately
also a plenthora of capacitive crossover effects and whatnot. So unless you are very skilled
(which I am not) then you can in my experience be better off if free realestate is simply
given a single big fat layer of copper fill.

Thanks to all you guys for making a really good program even better !

[jean-pierre charras (jp-charras)]

Merging zones with same net and same priority is the best way to manage zones.
However you can set a different priority to overlapping zones, even with the same net.