kicad-developers team mailing list archive

[Nick Østergaard <oe.nick@xxxxxxxxx>]

2017-05-01 8:25 GMT+02:00 jp charras <jp.charras@xxxxxxxxxx>:
>> Hi,
>>
>> Lachlan sent me a complex board in Eagle that has several copper zones,
>> each with different clearances, which filled incorrectly or didn't fill
>> at all. There were some trivial issues (e.g. inverted filling priority),
>> but there is one that needs discussion:
>>
>> In pcbnew, each zone must have manually assignned clearance (in the
>> property window). In Eagle or Altium, if there's no clearance specified,
>> the program takes the clearance set in the Design Rules for the net the
>> zone belongs to.
>>
>> I propose to add a similar feature to Kicad, that is:
>> - add a checkbox "use custom clearance" in the zone properties window
>> - if not checked, take the netclass clearance.
>>
>> This unfortunately requires a small file format change. Would you agree
>> with that?
>>
>> Also, many thanks to Lachlan for spotting this problem!
>>
>> Cheers,
>> Tom
>
> About zones clearances:
> the actual clearance is the min between the zone clearance and the netclass clearance.
> Therefore to use the netclass clearance, just set the zone clearance to 0
> (or to any value smaller than the netclass clearance).
> No need to change the file format.
>
> About clearance between board edges, or any obstacle, the Margin layer was intended to control this
> clearance, but not yet in used.
>

I have been wondering for a long time how this layer is supposed to be
used. I there any functionality associated with the layet at the time
of writing? If not, how is one supposed to use it when it is
implemented?

In my mind it makes sense to specify a pull back property to the edge
cuts lines.  AFIK the spec is usually to have a minimum pullback for
some reason, and if one needs more in some section of the board, then
it is not really a pull back in that sense anyway and should be
handled "manually" by adding a cutout or keepout zone. This is my
immediate thoughts on this, there may be use cases I have missed here.

> Note:
> For an unknown reason, I do not receive any mail from Launchpad since 3 days.
> So I have some problems when sending a response to a mail.
>
> --
> Jean-Pierre CHARRAS
>
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