X-Authentication-Warning: delorie.com: mail set sender to geda-user-bounces using -f
X-Recipient: geda-user AT delorie DOT com
X-Virus-Status: Clean
X-Virus-Scanned: clamav-milter 0.98.4 at av01.lsn.net
Subject: Re: [geda-user] The nature of gEDA layers
To: geda-user AT delorie DOT com
References: <alpine DOT DEB DOT 2 DOT 00 DOT 1601180756390 DOT 9035 AT igor2priv>
 <s6nr3h49hrq DOT fsf AT blaulicht DOT dmz DOT brux>
 <DDB07351-7C94-4B5C-99FA-83750CD4592A AT noqsi DOT com>
 <20160126233332 DOT dec2f06f5c74354a3841989c AT gmail DOT com>
 <s6n1t93h4ub DOT fsf AT blaulicht DOT dmz DOT brux>
 <20160127091746 DOT 1c7a976c2752f913921688ac AT gmail DOT com>
 <s6npowne74w DOT fsf AT blaulicht DOT dmz DOT brux>
 <20160127141334 DOT c738feb9dbeb54a7dec3dff8 AT gmail DOT com>
 <s6n37tjt1tv DOT fsf AT falbala DOT ieap DOT uni-kiel DOT de> <56A8F74B DOT 8080304 AT ecosensory DOT com>
 <CAC4O8c9UKLsh5FAAwUMEtHThKH-w3gUmCU2i9dRW9igkyRt-TQ AT mail DOT gmail DOT com>
 <CAJZxidDmjMtd_fKvR5qZVRa+hwDUbvfaz79oZjkBgDuE1m8RBg AT mail DOT gmail DOT com>
 <56A961BC DOT 3040405 AT ecosensory DOT com>
 <CAJZxidC=nbxAinOtpfGHHqwPXbEMrhfat7jKgA9KBp3EVVg4_Q AT mail DOT gmail DOT com>
 <s6nbn863xlu DOT fsf AT blaulicht DOT dmz DOT brux> <56A9E416 DOT 8080500 AT ecosensory DOT com>
 <s6nfuxirm0b DOT fsf AT falbala DOT ieap DOT uni-kiel DOT de>
 <CAC4O8c9D-F3p8sAm2UumoE+uoMZM1ufSP=mNEPeHHpn8YrcSyg AT mail DOT gmail DOT com>
 <20160128200126 DOT 0fe1bb26d5c28e59d56dfd0e AT gmail DOT com>
 <CAC4O8c8prUS=NSm_7BCwkCPntsCRRMCMu9--eXXVBtD0C4pYOg AT mail DOT gmail DOT com>
From: John Griessen <john AT ecosensory DOT com>
Message-ID: <56AA95B5.8030805@ecosensory.com>
Date: Thu, 28 Jan 2016 16:27:01 -0600
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101
 Icedove/38.4.0
MIME-Version: 1.0
In-Reply-To: <CAC4O8c8prUS=NSm_7BCwkCPntsCRRMCMu9--eXXVBtD0C4pYOg@mail.gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Reply-To: geda-user AT delorie DOT com
Errors-To: nobody AT delorie DOT com
X-Mailing-List: geda-user AT delorie DOT com
X-Unsubscribes-To: listserv AT delorie DOT com
Precedence: bulk

On 01/28/2016 02:22 PM, Britton Kerin (britton DOT kerin AT gmail DOT com) [via geda-user AT delorie DOT com] wrote:
>> The aim should be to change PCB in small incremental steps.
>> >
>> >- Remove the assumption that all layers except "outline" are conductive.
>> >- Make implicit layers explicit and allow to draw on them, soldermask, solderpaste.
>> >- Allow more/all things inside Elements, on explicit layers.
> This one in particular is not a small incremental step but a fairly
> drastic change.  A lot of work is likely to be required to fix all the
> points that make assumptions about Elements.  I'm not saying it's a
> bad idea, but it's hard.
>


Yeah, but this kind of item is what makes life easier from then on.
Some things are hard and deserve more than a quick patch fix, (More spaghetti code).

On 01/28/2016 02:46 PM, Britton Kerin (britton DOT kerin AT gmail DOT com) [via geda-user AT delorie DOT com] wrote:
 > Everyone seems to want these, to be honest I don't understand what
 > pads on middle layers are for.  Not mounting components for sure.  If
 > it's just a node what's wrong with a trace or poly?

They give strength and increased conductivity by bigger connection cross section area.
They serve as a large enough target for wandering drills to go through off center and still function well.
That kind of connection tolerance is important for low frequency and essential for HF, RF to avoid reflections.

John Griessen