Re: gEDA-user: what does "Error while clipping PBO_SUB: 3" mean?

[Mark Rages <markrages@xxxxxxxxx>]

On Wed, Feb 10, 2010 at 6:03 AM, Peter Clifton <pcjc2@xxxxxxxxx> wrote:
> On Wed, 2010-02-10 at 11:43 +0000, Peter Clifton wrote:
>>
>> The fact I don't see complaining - either means that I'm not taking
>> the
>> required steps to reproduce (ie.. what is subtracting from the polygon
>> if your lines are on a different layer?)
>
> Ok - read your bug report properly this time - and got answers to most
> of my questions.
>
> The following remain though.. what are the arcs and lines left on the
> component layer for? Just to show the outline?

yup

>
> How have you constructed a polygon which has a hole in it (Or is it not
> meant to have a big hole?)

it's actually a "C" shape that comes around and touches itself.

>
> PCB does not support defining a single ground-plane polygon with a hole
> in it. It can subtract holes out of one, but it does not support you
> defining its shape as anything other than a hole-less outline.

can I subtract arbitrary holes out of it?  how?

>
> If you have basically created a "C" shape, where the two ends of the C
> touch infintesimally, that "ought" to work, but if becomes very easy for
> numerical errors to get parts of the polygon self-intersecting.
>
> Could you elaborate how the polygon was constructed - obviously its too
> complex to have drawn by hand. I can imagine either a computer program,
> or using arcs + lines to clear away copper, then using the
> "MorphPolygons" action.
>

I wrote a python script which looks at lines and arcs and makes the
poly.  I don't have time to play with it now.  I put the script with
inputs and a Makefile describing the process at
http://vivara.net/software/line_arc_to_poly.tar.gz

> As you might imagine though, scanning lists of coordinates in the PCB
> file isn't particularly easy to do - and I don't have any debugging
> tools to help show the order in which a polygon contour is created.

Agree.

Regards,
Mark
markrages@gmail
-- 
Mark Rages, Engineer
Midwest Telecine LLC
markrages@xxxxxxxxxxxxxxxxxxx


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