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Date: Sun, 6 Apr 2014 13:23:16 +0200
From: Gabriel Paubert <paubert AT iram DOT es>
To: geda-user AT delorie DOT com
Subject: Re: [geda-user] Cooper arcs in footprint
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On Sun, Apr 06, 2014 at 02:12:56AM +0200, Stefan Salewski wrote:
> On Sat, 2014-04-05 at 19:49 -0400, Evan Foss wrote:
> > I had this problem last year. I was trying to do a footprint for a PCB
> > mounted microphone. In the end I had to approximate it by using a lot
> > of short strait traces at angles.
> 
> Indeed KiCad users had that problem, I guess they still have it.
> KiCad had no support for copper arcs at all about one year ago!
> 
> For your microphone there is a simple solution -- ad a copper arc in PCB
> editor after you had positioned the footprint with missing arc.
> 
> I still wonder why KiCad has avoided copper arcs so long, and why PCB
> avoided copper arcs in footprints. I think gerber formats supports arcs.

Indeed, but it does not support ellipses:

http://www.ucamco.com/files/downloads/file/81/the_gerber_file_format_specification.pdf

> One problem with arcs is: If we have stretched arcs, DRC may be much
> more difficult -- I have to admit that I have no idea how to test
> stretched arcs for intersection with other elements (fast). Another
> problem can be autorouting when we have arcs on the board -- for
> geometrical and topological routers there should be some difficulties.

Never used an autorouter myself, but they are quite useless for high frequency/RF work.

	Regards,
	Gabriel