X-Authentication-Warning: delorie.com: mail set sender to geda-help-bounces using -f
X-Recipient: geda-help AT delorie DOT com
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=gmail.com; s=20120113;
        h=mime-version:date:message-id:subject:from:to:content-type;
        bh=2No5slj0u7vr6Ke/3AC4o1hM0jJ50nowPIbyvrt0aaM=;
        b=Lipn+CNfqcIeUt1ZCtHyinMzIUZ5fGV5SV+yPjm0YU/qNMrQ8J8X+3PbBamNjiSOP+
         c3pLOGq7ue3yyiI1A1qeI01diy6i3poA7+jFw70oEhwSyAMcxkTCGpiy5BvsH12XXNhr
         vs2c3v554188gle5DZpjHCyZ0wwMMjX4erztUbd2wYhhKnAG1YpYP6muwovfbdeP8dsj
         amqOSS+CQkZg1y8o5b2f1bZOkJSUvpNlHm3vtpKvcynzRIJdy58m7iCKbpQZDfKt2mJr
         hFsyAepjVv8/uq3XlC5x12ZVu9cMoQquPCVoR9CdDhywFeFLaYuTrjkHg7D8VeF3hQ8V
         0j8w==
MIME-Version: 1.0
X-Received: by 10.50.126.100 with SMTP id mx4mr32561817igb.1.1408222585435;
 Sat, 16 Aug 2014 13:56:25 -0700 (PDT)
Date: Sat, 16 Aug 2014 16:56:25 -0400
Message-ID: <CAAhxy3DyESymfA64xKNhsH9rrqJhjZH7H6zYeCDW-jGczHjBMg@mail.gmail.com>
Subject: [geda-help] irregular pads, hidden dangers
From: vattan <vatan DOT uml AT gmail DOT com>
To: "geda-help AT delorie DOT com" <geda-help AT delorie DOT com>
Content-Type: text/plain; charset=UTF-8
Reply-To: geda-help AT delorie DOT com

I often worry about how a creative solution may break something behind
the scenes in software.  Today I am worrying over odd pad shapes, and
if getting creative will just get me in trouble.
If you take a look at the datasheet for LM2596 and flip to page 39 you
will see a suggested pattern for the thermal pad behind it, where it
is a kind of T shape. I could make that with two boxes edge to edge,
or with overlap.  I am scared however of how this may be handeld in
the background and if it may cause wierd isolation patterns or
somthing subtle that i will not notice but a production house may
choke on.  From my limited expereince with code,  I know that zero
thickness areas can be subtly tricky from a code point of view, so
that scares me the most.   overlap is probably well handled, but I
don't know if it will throw up an error anywhere else.

currently my part is deisgned w/ a simple square pad, but I am curiuos
what the community/devs think of my concerns.  I am doing a little
brute force testing, but I am new  to board desig nso I don't really
know all the ways these things can go wrong.