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Subject: Re: [geda-user] Pcb: Automatic clearance between polygons?
To: geda-user AT delorie DOT com
References: <3721c0b4-2805-2d9f-eba0-119c9c2dd81e AT linetec DOT nl>
<CAJZxidAFqANGm2MofmyeSVTZyRS+YCS16-JtfAidjwYHoKE0GQ AT mail DOT gmail DOT com>
From: "Richard Rasker (rasker AT linetec DOT nl) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
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Date: Wed, 15 Jan 2020 14:30:08 +0100
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Hello Chad,

Op 13-01-20 om 20:40 schreef Chad Parker (parker DOT charles AT gmail DOT com) [via 
geda-user AT delorie DOT com]:
> Hi Richard-
>
> What's wrong with wide traces? The end caps?

Traces are OK for simpler shapes. The problem is that they have a fixed 
width and (of course) do not clear pads and pins. So for a more complex 
shape, I'd have to use a thin trace to make the outline, and then 
'colour it in' using lots more traces.

> What about using a large element pad for your connections instead of a 
> polygon?

This is even less convenient, as it requires defining separate pads for 
each situation.

For example, I have four 0.5W 0805 resistors that need as much copper as 
possible to dissipate heat, located amidst other components. So for each 
of these resistors, I draw two polygons covering the desired area, 
connected to the pads by setting a zero clearance gap (Shift+K) for each 
pad. No problems so far, as other pins, pads and traces still have 
automatic clearance with regard to this polygon.

However, when I want to fill up the remaining space with a ground plane, 
I need to manually steer clear of the polygons that are already present, 
which can be quite a bit of fiddly work. Not really a problem, but 
time-consuming all the same. It would be nice if a polygon had a 
'clearance gap' parameter that would make other polygons observe a 
certain clearance, just as they do with all other elements.

But as said, I just wondered if I overlooked an option all those years 
-- it is more of a nuisance than a real problem.

> I'll have to look and see if there any facility for polygon-polygon 
> clearance. I've only delved into polygons a couple times, but I have a 
> vague recollection of something.

Well, I'd be most interested! And of course I'll be glad to do any testing.

Thanks already,

Richard Rasker


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