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Re: Question about odd pad shapes


On Thu, Jul 05, 2012 at 01:13:40PM -0700, Roger Marin wrote:
>  I'm one of those who silently read the Kicad developer discussions.
>  Please forgive my jumping in here...

The list is public and feedback is welcome (and useful)

>  Yes, if needed, you *can* create a filled copper zone in a module.

Technically yes, since you can use trapezoidal pads to tile whatever area you
want (since they can degenerate to axis aligned triangles, I think it could be
proved that such a decomposition is always possible).

But drawing a polygon in the module and saying 'I want that filled with copper'
no, that's not possible. It *could* be done with either a new kind of module
primitive or really enhanced pad support (look in gerber aperture macros, the
primitive 4 allows you 4000 vertices in a *pad* :D); there is also the
conventional gerber fill which is already used for regular zones.

>  circumvent some of the more frustrating design enforcement features
>  that are a part of the Kicad design philosophy.

Uhmm... part is design philosophy, part is missing features:P Look at gencad,
in that old format you can't even *express* trapezoidal pads... (in kicad we
don't have padstacks, so I guess the score is even)

>  Attached is a "thrown together" .MOD that started life as a .BRD,
>  was stuffed through BRD2EMP, imported into Pcbnew's module editor,
>  then saved as a .MOD . Please note that text cleanup or pin
>  renumbering was not done in the module editor phase.

Going *too* crazy with strange pads can give headaches with board testers.
Also it seems that your converter raster fills an area which is a big no for
gerber these days:P

As always it depends on your fabricator software/engineer (I've seen boards
rejected because they used AM and their importer was flaky and didn't recognize
the netlists...)

>  BTW: Today, after creating the test EMP, I found that the module
>  editor from the latest main bzr release throws a biuParse() exception
>  while loading the EMP. No such problem exists with the stable release

Is the 'loading' kicad nano enabled? I filed a bug with EMP handling a while
ago, maybe they're related (it was a really weird scaling issue, but who know).

Lorenzo Marcantonio
Logos Srl