Mail Archives: geda-user/2016/01/27/13:40:32
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Hello-
I realize I'm not a frequent contributor to these discussions, and
consequently have no real "street cred", so feel free to disregard my
remarks. With that said, perhaps I can provide a perspective that someone
will find useful.
I would suggest that a layer is really more of a container than anything
else, it is a way of collecting and grouping objects. Ultimately the group
of objects is interpreted in a particular way when a board is fabricated,
perhaps as copper, perhaps as a board outline, perhaps as a silkscreen...
or perhaps as something else entirely. Anyway, the point is that the
concept of a layer is really a more general abstraction and the physicality
of them is an interpretation. Keep the concept of a layer simple, and let
the concerns of interpretation and realization happen at a higher level
such as DRC, a board house, a chip fab, a technician, etc.
The other comment I would make, is that it seems like some of these
discussions could be leading towards some very fundamental changes in the
core of pcb. I don't know if anyone has thought much about a version road
map, but such major architectural changes tend to happen as new major
version releases. If in fact such major changes are actually being
considered for implementation, it may be well worth it to sketch out a map
so you can see where effort is best expended. For example, which bugs do
you actually want to fix in the current version and what things are better
worked into the next version with the new core.
This is just my 2 cents.
Cheers,
--Chad
On Wed, Jan 27, 2016 at 12:32 PM, Britton Kerin (britton DOT kerin AT gmail DOT com)
[via geda-user AT delorie DOT com] <geda-user AT delorie DOT com> wrote:
> On Wed, Jan 27, 2016 at 7:58 AM, John Griessen <john AT ecosensory DOT com>
> wrote:
> > On 01/27/2016 10:38 AM, Stephan B=C3=B6ttcher wrote:
> >>>
> >>> There is no via layer,
> >>
> >> Yes there is, in my proposeal.
> >>
> >>> >a via is a composite of objects on different layers.
> >>
> >> That is true. Including the layer that tells what is conductively
> >> connected.
> >
> >
> > This needed a new subject line.
> >
> > How about my proposal of the previous email, "layers correspond and
> > represent physical planar layers,
> > and outline is a special mask layer that acts on physical layers. Via
> could
> > also be in the mask layer
> > category -- mask layers "act on" physical definition layers...
> >
> > I'd like to call them that way --
> > mask layers
> > physical definition layers
>
> Seem mostly reasonable but I'd still hesitate a bit. Advertising
> layers as having particular physical meaning is both more ambitious
> and more limiting than just having them be "something like what they
> look like in pcb". It's possible that the current representation
> might have multiple useful physical realizations, and once you start
> making assumptions about precise physical meaning some of them might
> be lost.
>
> Britton
>
>
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<div dir=3D"ltr"><div><div><div><div><div><div>Hello-<br><br></div>I realiz=
e I'm not a frequent contributor to these discussions, and consequently=
have no real "street cred", so feel free to disregard my remarks=
. With that said, perhaps I can provide a perspective that someone will fin=
d useful.<br><br></div>I would suggest that a layer is really more of a con=
tainer than anything else, it is a way of collecting and grouping objects. =
Ultimately the group of objects is interpreted in a particular way when a b=
oard is fabricated, perhaps as copper, perhaps as a board outline, perhaps =
as a silkscreen... or perhaps as something else entirely. Anyway, the point=
is that the concept of a layer is really a more general abstraction and th=
e physicality of them is an interpretation. Keep the concept of a layer sim=
ple, and let the concerns of interpretation and realization happen at a hig=
her level such as DRC, a board house, a chip fab, a technician, etc.<br><br=
></div>The other comment I would make, is that it seems like some of these =
discussions could be leading towards some very fundamental changes in the c=
ore of pcb. I don't know if anyone has thought much about a version roa=
d map, but such major architectural changes tend to happen as new major ver=
sion releases. If in fact such major changes are actually being considered =
for implementation, it may be well worth it to sketch out a map so you can =
see where effort is best expended. For example, which bugs do you actually =
want to fix in the current version and what things are better worked into t=
he next version with the new core.<br><br></div>This is just my 2 cents.<br=
></div>Cheers,<br></div>--Chad<br><div><div><div><div><div><div><br><br></d=
iv></div></div></div></div></div></div><div class=3D"gmail_extra"><br><div =
class=3D"gmail_quote">On Wed, Jan 27, 2016 at 12:32 PM, Britton Kerin (<a h=
ref=3D"mailto:britton DOT kerin AT gmail DOT com">britton DOT kerin AT gmail DOT com</a>) [via <a=
href=3D"mailto:geda-user AT delorie DOT com">geda-user AT delorie DOT com</a>] <span dir=
=3D"ltr"><<a href=3D"mailto:geda-user AT delorie DOT com" target=3D"_blank">ged=
a-user AT delorie DOT com</a>></span> wrote:<br><blockquote class=3D"gmail_quot=
e" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">=
<span class=3D"">On Wed, Jan 27, 2016 at 7:58 AM, John Griessen <<a href=
=3D"mailto:john AT ecosensory DOT com">john AT ecosensory DOT com</a>> wrote:<br>
> On 01/27/2016 10:38 AM, Stephan B=C3=B6ttcher wrote:<br>
>>><br>
>>> There is no via layer,<br>
>><br>
>> Yes there is, in my proposeal.<br>
>><br>
>>> >a via is a composite of objects on different layers.<br>
>><br>
>> That is true.=C2=A0 Including the layer that tells what is conduct=
ively<br>
>> connected.<br>
><br>
><br>
> This needed a new subject line.<br>
><br>
> How about my proposal of the previous email, "layers correspond a=
nd<br>
> represent physical planar layers,<br>
> and outline is a special mask layer that acts on physical layers.=C2=
=A0 Via could<br>
> also be in the mask layer<br>
> category -- mask layers "act on" physical definition layers.=
..<br>
><br>
> I'd like to call them that way --<br>
> mask layers<br>
> physical definition layers<br>
<br>
</span>Seem mostly reasonable but I'd still hesitate a bit.=C2=A0 Adver=
tising<br>
layers as having particular physical meaning is both more ambitious<br>
and more limiting than just having them be "something like what they<b=
r>
look like in pcb".=C2=A0 It's possible that the current representa=
tion<br>
might have multiple useful physical realizations, and once you start<br>
making assumptions about precise physical meaning some of them might<br>
be lost.<br>
<br>
Britton<br>
<br>
</blockquote></div><br></div>
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