On Jan 27, 2016, at 11:40 AM, Chad = Parker (parker DOT charles AT gmail DOT com) = [via geda-user AT delorie DOT com] = <geda-user AT delorie DOT com>= wrote:

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.

Oh, no. The way it works around here, you lose cred by contributing to = the discussion ;-)

I would suggest that a = layer is really more of a container than anything else, it is a way of = collecting and grouping = objects.

I = would not call that a layer at all. A layer represents a hunk of copper, = epoxy glass, ink, etc. What you=92re talking about should be called a = =93pattern=94, I think: it edits the arrangement of material on one or = more layers.

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. =

That=92s why = you should not use the term =93layer=94 here: it promotes = confusion.

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=F6ttcher 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

John Doty Noqsi = Aerospace, Ltd.

http://www.noqsi.com/

jpd AT noqsi DOT com

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