Re: gEDA-user: DRC problem at close pads

[David Kuehling <dvdkhlng@xxxxxx>]

>>>>> "Dan" == Dan McMahill <dan@xxxxxxxxxxxx> writes:

> David Kuehling wrote:
>>>>>>> "DJ" == DJ Delorie <dj@xxxxxxxxxxx> writes:
>>
>>>> http://user.cs.tu-berlin.de/~dvdkhlng/clearance-problem.png
>>
>>> Could you post (or send me privately) the .pcb file?
>> Here is a simplified file that only contains the problematic
>> footprint.  Quite possibly this is just a problem with the footprint?
>> After all this was hand-coded in M4...

> I'd be more likely to suspect the footprint if "after all it was hand
> drawn instead of generated programattically"...

> Ok, here's the deal.  It is a bug in pcb.  Square (or rectangular)
> pads are checked by growing one of them in X and Y on all 4 sides by
> the minimum space.  This of course means that the corners grew by
> sqrt(2) more and thats why you got a failures.  I'll try to cook up a
> patch tonight.

Yes, I now remember having seen some illustration in the PCB user guide
(section 7), illustrating how lines (pads) with rectangular ends are
drawn by a rectangular aperture (on page 57).

The clearance is drawn as a rectangle, so one could take the current
behaviour as being right.  Else somebody would have to fix the
documentation :)

I already reworked my footprint, moving the pads a little outwards.
Hopefully this will work in production (but since there isn't an
oficially recommended pcb layout for the chip in question the footprint
is a rough guess anyway).

Thanks also for your patch.  But since my layout already changed, there
might not be much testing that I can do.  I'm going to upgrade PCB
anyway before exporting the final gerber files (I heard of some problems
which aren't fixed yet in pcb-2006082) and will then test the patch.

regards,

David
-- 
GnuPG public key: http://user.cs.tu-berlin.de/~dvdkhlng/dk.gpg
Fingerprint: B17A DC95 D293 657B 4205  D016 7DEF 5323 C174 7D40



_______________________________________________
geda-user mailing list
geda-user@xxxxxxxxxxxxxx
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user