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Date: Thu, 28 Jan 2016 19:48:04 -0500
Message-ID: <CAJZxidBMy9r01RN=NYZg=k=6MpiJNuwKf=uHBj_8LkE1A_iQ1Q@mail.gmail.com>
Subject: Re: [geda-user] The nature of gEDA layers
From: "Chad Parker (parker DOT charles AT gmail DOT com) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
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Clearly I've demonstrated my ignorance regarding the DRC, and it wasn't
really my intent to discuss BBVias. I hope that I can ask some intelligent
questions about these topics, but perhaps I will do that in a different
thread at another time.

My purpose in speaking up this time was really just to suggest a model for
how the to think about layers, so for the moment I will stick to that.

BBVias need to have pads only on the relevent layers, which requires
> some change, as well as the drill changes.


Is this not also true for through-hole components? They don't really need
to have pads on an internal layer unless you're connecting a trace to it on
that layer. Although, I can't think of an instance in which I have ever
seen a through-hole pad stack that omitted any inner layer pads, so perhaps
there's a reason I'm not aware of. I'm sure someone will be eager to
enlighten me :)


> Remember, it's not just gerber, it's also gcode, png, ps, and whatnot.
>

I have tried to keep that in mind, and the variety of output formats that
need to be supported seems to be to be a strong justification for keeping
things simple and generic. If you base your data structures and primitives
on a particular output format, then you may well be making it more
complicated to produce all of the other output formats. With that said, if
you base your data structures on a particular format, at least you can
output that format easily. Poorly designed data structures could make it
difficult to output every format! (please note that I am not making any
judgements about the current code base here. As I've already said, my
familiarity with it is 0.)

Someone needs to do the work.
>

Yup. This is really what it all comes down to. It's easy to sit here and
theorize about how things ought to be done. But I've always found work to
be a lot easier if I have a solid plan of what I'm going to do and where
I'm going before I start. Hopefully that's what this discussion will be.

Cheers,
--Chad

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<div dir=3D"ltr">Clearly I&#39;ve demonstrated my ignorance regarding the D=
RC, and it wasn&#39;t really my intent to discuss BBVias. I hope that I can=
 ask some intelligent questions about these topics, but perhaps I will do t=
hat in a different thread at another time.<br><br>My purpose in speaking up=
 this time was really just to suggest a model for how the to think about la=
yers, so for the moment I will stick to that.<br><div><div class=3D"gmail_e=
xtra"><br><div class=3D"gmail_quote"><blockquote class=3D"gmail_quote" styl=
e=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);paddin=
g-left:1ex"><span class=3D"">
</span>BBVias need to have pads only on the relevent layers, which requires=
<br>
some change, as well as the drill changes.=C2=A0 </blockquote><div><br>Is t=
his not also true for through-hole components? They don&#39;t really need t=
o have pads on an internal layer unless you&#39;re connecting a trace to it=
 on that layer. Although, I can&#39;t think of an instance in which I have =
ever seen a through-hole pad stack that omitted any inner layer pads, so pe=
rhaps there&#39;s a reason I&#39;m not aware of. I&#39;m sure someone will =
be eager to enlighten me :)<br>=C2=A0</div><blockquote class=3D"gmail_quote=
" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);=
padding-left:1ex">Remember, it&#39;s not just gerber, it&#39;s also gcode, =
png, ps, and whatnot. <span class=3D""><br></span></blockquote><div><br></d=
iv><div>I have tried to keep that in mind, and the variety of output format=
s that need to be supported seems to be to be a strong justification for ke=
eping things simple and generic. If you base your data structures and primi=
tives on a particular output format, then you may well be making it more co=
mplicated to produce all of the other output formats. With that said, if yo=
u base your data structures on a particular format, at least you can output=
 that format easily. Poorly designed data structures could make it difficul=
t to output every format! (please note that I am not making any judgements =
about the current code base here. As I&#39;ve already said, my familiarity =
with it is 0.)<br><br><blockquote style=3D"margin:0px 0px 0px 0.8ex;border-=
left:1px solid rgb(204,204,204);padding-left:1ex" class=3D"gmail_quote"> So=
meone needs to do the work.<br></blockquote></div></div><br></div><div clas=
s=3D"gmail_extra">Yup. This is really what it all comes down to. It&#39;s e=
asy to sit here and theorize about how things ought to be done. But I&#39;v=
e always found work to be a lot easier if I have a solid plan of what I&#39=
;m going to do and where I&#39;m going before I start. Hopefully that&#39;s=
 what this discussion will be.<br></div><div class=3D"gmail_extra"><br></di=
v><div class=3D"gmail_extra">Cheers,<br></div><div class=3D"gmail_extra">--=
Chad<br></div></div></div>

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