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Date: Fri, 17 Mar 2017 08:48:15 +0100 (CET)
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To: "Chad Parker (parker DOT charles AT gmail DOT com) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
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Subject: Re: [geda-user] [pcb-rnd] tEDAx footprint load support
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On Tue, 14 Mar 2017, Chad Parker (parker DOT charles AT gmail DOT com) [via geda-user@=
delorie.com] wrote:

>            =C2=A0- Holes without plating is common.
>
>
>      Common, but not essential. The same footprint could work fine
>      with plated holes.
>
>=C2=A0
>Not always. In much of my work I'm not allowed to use pth for any kind of
>mounting hole, which would include holes for screwing into things like hea=
t
>sinks and packages that might be included in a footprint.
>
>      Question (to all PCB engineers): how often do you rely on the
>      clearance value set in a footprint?
>
>
>My clearances are typically defined at the board level by my netlist and m=
y
>geometry. I can't think of a time I've ever defined a clearance in a
>footprint that wasn't highly specialized.

Which means you import the footprint and (in whatever way) change the=20
clearance to fit your board's needs, right? In other words, it doesn't=20
really matter what clearance value is in the footprint, you don't=20
rely on that value.

At least that's what I always do, and I somewhat expected the same with=20
plating.

Anyway, I've added a "hints" field to the hole line. I've also added some=
=20
explanation about how much the plated/unplated hint and the clearance are=
=20
optional. Also updated pcb-rnd to emit and load the new field.

Rationale:

tEDAx is not about trying to unify the internal model of all EDA software.=
=20
It's only about making it possible to share data with low implementation=20
cost, even if that means losing some details. So I keep clearance and now=
=20
it is possible to describe a hint for plated/non-plated, but I don't=20
expect every implementation to fully understand and respect these values.

I believe users should check and fine tune those details when they start=20
using a new footprint from whatever external source. Especially if they=20
are doing something fancy/expensive.

Regards,

Igor2
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