Mail Archives: geda-user/2015/06/25/17:43:04
On Thu, 2015-06-25 at 18:37 +0200, Gabriel Paubert (paubert AT iram DOT es)
wrote:
> Actually, I'm chasing the annoying bug that sometimes happens of a small
> sliver of copper that creates shorts under very specific conditions and
Did you try the patches I posted a while back... (15/02/2015). Email
subject was "PCB users - Call for testing of polygon fixes"
Unfortunately, I never quite finished cleaning up the remaining issues
(mostly sanity checking the logic of a few things, and cleaning up some
error-cases).
The patches contain descriptions of the problems they fix, including
some test-cases. From your description, it might be relevant to the bugs
you mentioned.
Perhaps you could see if they help in any of the files you have problems
with).
> I've been diving in the polygon code for 2 days and a half, because it
> caused systematic problems when generating Gerber files for a moderately
> complex board: 80x200mm, ~680 components, but "only" 2000 pads since it's
> relativly high frequency (up to 1GHz) and roughly half the components are
> capacitors of various sizes (60 of them 0201, the rest mostly 0603 with
> quite a few 1206 and some 0402 thrown in, three EIA7343 tantalum).
One interesting Gerber file issue, is that board houses sometimes use
only "flashed" pads for generating automatic test programs for flying
probe testers.
PCB doesn't (IIRC) generate flashed pads, at least not for all shapes. -
I've had at least one case (I think) where boards have "passed"
automatic testing, with manufacturing defects still present, and I think
the underlying cause may have been the fab house's inability to
auto-extract the pad locations.
Ultimately, the gerber output HID should create macros for any shapes it
needs, and always flash pads. (Sadly I've no time to dive in myself).
This would also significantly reduce file-size, keeping the existing
clearance shapes.
> Anyway, the patch is appended, it boils down to:
> - adding a new flag called "squareclearance" that changes the behaviour
> of the clearance for non-circular pads and pins.
> - enable this feature by essentially copying the code fragments for the
> "square" flag and renaming square to squarecleareance with appropriate
> UPPER/lower/CamelCase.
> - map the corresponding Toggle action to Alt-Q
What was the use-case for this? (Stylistic, electrical design
requirement, or workaround for the large / buggy gerber output?)
I'm not against the possibility of this, but I do find the proliferation
of flags somewhat distasteful. I guess we never did get around to that
all encompassing file-format update.
> - change some of the internal ABI of the polygon code that really
> annoyed me, as well as reordering some structures for better packing.
I'd be interested to see some/all of these change (clean or not), so I
can inform myself before protesting against them ;). Ugly as the polygon
code is, I've several WIP development branches that might be broken by
major API changes.
--
Peter Clifton <peter DOT clifton AT clifton-electronics DOT co DOT uk>
Clifton Electronics
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