delorie.com/archives/browse.cgi   search  
Mail Archives: geda-user/2012/12/13/23:14:10

X-Authentication-Warning: delorie.com: mail set sender to geda-user-bounces using -f
X-Recipient: geda-user AT delorie DOT com
Mime-Version: 1.0 (Apple Message framework v1085)
Subject: Re: [geda-user] Find rat lines
From: John Doty <jpd AT noqsi DOT com>
In-Reply-To: <5AA18F19-2EA9-4E7D-9378-F768D8E1E5DD@jump-ing.de>
Date: Thu, 13 Dec 2012 21:12:45 -0700
Message-Id: <3A16FC8A-FDE6-47F0-8EA9-C5E4580DE7BE@noqsi.com>
References: <20121204183305 DOT 6b04c0dc AT jive DOT levalinux DOT org> <20121208112649 DOT 388a9d22 AT jive DOT levalinux DOT org> <1355011808 DOT 19390 DOT 8 DOT camel AT localhost> <alpine DOT DEB DOT 2 DOT 00 DOT 1212090407031 DOT 26605 AT igor2priv> <1355188647 DOT 12937 DOT 14 DOT camel AT localhost> <A7B4EDBD-3704-4837-9350-A16559C60A2A AT noqsi DOT com> <201212140010 DOT qBE0ABjV023762 AT envy DOT delorie DOT com> <172CCAAB-0423-43EF-8A04-5A9961F1D5B9 AT noqsi DOT com> <201212140122 DOT qBE1MoKM019255 AT envy DOT delorie DOT com> <5AA18F19-2EA9-4E7D-9378-F768D8E1E5DD AT jump-ing DOT de>
To: geda-user AT delorie DOT com
X-Mailer: Apple Mail (2.1085)
X-MIME-Autoconverted: from quoted-printable to 8bit by delorie.com id qBE4CpM5019540
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

On Dec 13, 2012, at 7:59 PM, Markus Hitter wrote:

> 
> Am 14.12.2012 um 02:22 schrieb DJ Delorie:
> 
>> Even something as simple as adding a single trace could "short"
>> multiple existing subnets, and if some of those subnets have been
>> assigned to nets but some subnets are as yet unassigned (because they
>> have yet to connect to something known to be in the netlist), you get
>> lots of arbitrary choices to be made about how everything needs to be
>> resolved.
> 
> Don't wanna defend Mr. Doty here, but at least his appearance gave me some inspiration. How would gschem handle this "shorted tracks" problem?
> 
> It doesn't, because gschem tracks don't short by just lying atop of each other. 

I don't wanna be impolite to my defender, but the gschem case is different. Gschem is a schematic editor: it has no need to understand connectivity. Indeed, for maximum flexibility it should not. But a conductor on a printed circuit board is usually a part of a specific net, and if it isn't, any contact with any other conductor needs to be considered a "short" unless specifically authorized.

>  Except in certain conditions, where the short is actually wanted.
> 
> Conveniently, this pretty much applies to rat lines as well; enter pcb.
> 
> To get a more gschem-like behaviour in pcb, pcb would have to give up drawing arbitrary, disconnected tracks. It would have to stop connecting tracks by just drawing them at the same place. Sounds ridiculous, doesn't it?

It seems to me that a freshly drawn piece of conductor should have defined affinities. Of course, for a "floating" object (HV guard ring, antenna element, etched-in text) it might just be "floating".

> 
> Possible solution: instead of drawing tracks, board design starts with rat lines. Like we currently have them. Then, these rat lines are - sort of - pinned down to become, or being morphed into tracks. Perhaps with a tool similar to how paths are edited in drawing applications. Add vertices, drag these vertices, join them to forks, and so on, until the board is done. But never disconnect a track in this process.

That would make a lot of sense to me, anyway.

> 
> This way, tracks are never disconnected from a net. Finding a short becomes trivial. Probably a number of other tasks, like track length measurement, too.
> 
> OK, I have no code. But I couldn't resist to forward this inspiration, either.
> 
> 
> Thanks for listening,
> Markus
> 
> - - - - - - - - - - - - - - - - - - -
> Dipl. Ing. (FH) Markus Hitter
> http://www.jump-ing.de/
> 
> 
> 
> 
> 
> 

John Doty              Noqsi Aerospace, Ltd.
http://www.noqsi.com/
jpd AT noqsi DOT com



- Raw text -


  webmaster     delorie software   privacy  
  Copyright 2019   by DJ Delorie     Updated Jul 2019