X-Authentication-Warning: delorie.com: mail set sender to geda-user-bounces using -f X-Recipient: geda-user AT delorie DOT com Message-ID: <53BCDC7E.5040001@sonic.net> Date: Tue, 08 Jul 2014 23:09:02 -0700 From: Dave Curtis User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:16.0) Gecko/20121028 Thunderbird/16.0.2 MIME-Version: 1.0 To: geda-user AT delorie DOT com Subject: Re: [geda-user] pour clearing around pads References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------070105090007010700020702" X-Sonic-ID: C;apcuhi8H5BGZkmuUdPQXfw== M;yslkhi8H5BGZkmuUdPQXfw== X-Spam-Flag: No X-Sonic-Spam-Details: 0.0/5.0 by cerberusd Reply-To: geda-user AT delorie DOT com This is a multi-part message in MIME format. --------------070105090007010700020702 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 07/08/2014 11:17 AM, Peter Clifton wrote: > Please don't use zero width pads... OK :) > > The file format makes no guarantee how they behave, and it seems like > the special case free situation should view them as an under width DRC > error. Yes, its a total belly-flop onto "maybe it happens to work." > > Adding support for defining additional mask within a footprint should > not be insurmountable, just needs in the first instance, someone to > define the extension to the file format. Extending the file format is the easy part. I can come up with lots of ideas for syntax. And I could have a patch for the flex .l-file in minutes and recognize the the constructs in the bison code quite quickly as well. It's getting past that point is where we smack into a wall -- it's not clear to me that the internal data structures are ready to accept copper-clearance and mask-clearance features that are not associated with a pad or a pin. A friend across town has been using KiCad for a while, and since we are interested in building the same sorts of things we try to share what we can in terms of tools and designs. Right now, we are hot on the "grand, unified, footprint generator script" problem. We would like to come up with a single front-end that can create footprints for both pcb and KiCad so that we could share footprints more easily. So... I've been looking at the KiCad footprint file format and their new one can handle a lot of things that are somewhat vexing in pcb -- although I'm not too hot on the S-expression idea overall. Anyway, KiCad seems to leave some things out that my friend and I have been talking about -- like keep-outs. So the point of the above paragraph is, yes, I can suggest some extensions, and now would be a good time to capture that since I am trying to wrap my head around the issues right now. What I can do: 1. write up some straw-man spec extensions 2. update the "footprint creation for.." document with what ever settles out of that. What I can not do: Investigate the feasibility of implementing the extensions. I simply don't know the code well enough. -dave > > Peter > > > --- > Peter Clifton > > (Sent from my phone) > > -------- Original message -------- > From: DJ Delorie > Date:07/07/2014 19:00 (GMT+00:00) > To: geda-user AT delorie DOT com > Subject: Re: [geda-user] pour clearing around pads > > > > I'm not sure where to look for how a zero-thickness pad might cause > > phantom shorts or how it interacts with route blocking. Clues welcome. > > The code considers a pad to be a line segment between two points, and > may do a "do these segments intersect" test independent of the "check > the width" test. djopt, I think, does this - intersection of segments > is a different test than the "happen to touch due to width" test. --------------070105090007010700020702 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by d.mail.sonic.net id s69692LI025864
On 07/08/2014 11:17 AM, Peter Clifton wrote:
Please don't use zero width pads...
OK :)

The file format makes no guarantee how they behave, and it seems like the special case free situation should view them as an under width DRC error.
Yes, its a total belly-flop onto "maybe it happens to work."

Adding support for defining additional mask within a footprint should not be insurmountable, just needs in the first instance, someone to define the extension to the file format.
Extending the file format is the easy part.=C2=A0 I can come up with = lots of ideas for syntax. And I could have a patch for the flex .l-file in minutes and recognize the the constructs in the bison code quite quickly as well.=C2=A0 It's getting past that point is where we smack into a wall -- it's not clear to me that the internal data structures are ready to accept copper-clearance and mask-clearance features that are not associated with a pad or a pin.

A friend across town has been using KiCad for a while, and since we are interested in building the same sorts of things we try to share what we can in terms of tools and designs.=C2=A0 Right now, we are ho= t on the "grand, unified, footprint generator script" problem.=C2=A0=C2=A0= We would like to come up with a single front-end that can create footprints for both pcb and KiCad so that we could share footprints more easily.=C2=A0 So... I've been looking at the KiCad footprint file for= mat and their new one can handle a lot of things that are somewhat vexing in pcb -- although I'm not too hot on the S-expression idea overall.=C2=A0 Anyway, KiCad seems to leave some things out that my friend and I have been talking about -- like keep-outs.=C2=A0

So the point of the above paragraph is, yes, I can suggest some extensions, and now would be a good time to capture that since I am trying to wrap my head around the issues right now.=C2=A0 What I can = do:

1. write up some straw-man spec extensions
2. update the "footprint creation for.." document with what ever settles out of that.

What I can not do:

Investigate the feasibility of implementing the extensions.=C2=A0 I simply don't know the code well enough.

-dave


Peter


---

(Sent from my phone)

-------- Original message --------
From: DJ Delorie
Date:07/07/2014 19:00 (GMT+00:00)
To: geda-user AT delorie DOT com
Subject: Re: [geda-user] pour clearing around pads


> I'm not sure where to look for how a zero-thickness pad might cause
> phantom shorts or how it interacts with route blocking.=C2=A0 Clues welcome.

The code considers a pad to be a line segment between two points, and
may do a "do these segments intersect" test independent of the "check
the width" test.=C2=A0 djopt, I think, does this - intersection o= f segments
is a different test than the "happen to touch due to width" test.

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