Re: gEDA-user: Breaking up power planes

[Russell Dill <russd@xxxxxxx>]

On Mon, Feb 21, 2011 at 12:40 AM, Stephan Boettcher
<boettcher@xxxxxxxxxxxxxxxxxx> wrote:
> Russell Dill <russd@xxxxxxx> writes:
>
>> On Sun, Feb 20, 2011 at 10:05 AM, Kai-Martin Knaak <kmk@xxxxxxxxxxxx> wrote:
>>> Russell Dill wrote:
>>>
>>>> I'm just wondering what everyones preferred method of breaking up
>>>> power/ground planes is.
>>>
>>> My preferred method is to break the planes as little as possible :-)
>>> IMHO, a continuous copper plane is the best you can get for shielding
>>> purposes. If large amounts current need to be canalized, I prefer to
>>> guide them in fat tracks rather than polygons. With tracks it is easier
>>> to ensure a minimum diameter.
>>>
>>
>> My design has several different power and IO rails, and so it requires
>> split power planes.I realize its possible to do with the polygon
>> editor, it just seems like it'd be much easier with the line drawing
>> tool.
>
> You want to split a polygon into different nets? ÂDoes that work? ÂEven
> if you invoke the special magic to not loose isolated parts of the
> polygon, will the connectivity check treat them as separate copper and
> assign them to different nets?
>
> I've drawn separate polys for each power/gnd net on my boards.
>
> Let's see, ok, it does work. ÂI'd still be uncomfortable with such a
> layout.
>

I haven't had the chance to test it yet, but I just found the magic
command that completes the cycle:

---
MorphPolygon(Object|Selected)

Converts dead polygon islands into separate polygons.

If a polygon is divided into unconnected "islands", you can use this
command to convert the otherwise disappeared islands into separate
polygons. Be sure the cursor is over a portion of the polygon that
remains visible. Very small islands that may flake off are
automatically deleted.
---

So draw a polygon pour that fills the board, then draw traces that
clear the desired amount of spacing to split up the planes. Perform a
:MorphPolygon(Object), and then delete the traces. Of course, editing
is still a bit of an issue.


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