kicad-developers team mailing list archive

[Strontium <strntydog@xxxxxxxxx>]

Hi Piers,

On 20/12/15 00:24, Piers Titus van der Torren wrote:
> Hi Wayne,
> If I can add my thoughts, I think Steven has a fair point that 
> tracking zones in the DRC is non trivial, so a 'real' solution in that 
> direction is not around the corner, and will never be perfect either.
Yes, I think there will always be corner cases, and this patch cleans up 
those corner cases by not unnecessarily changing nets on tracks/vias 
laid by a designer.
> The proposed change has as side effect that unconnected tracks without 
> a zone connection also will keep their net, until another net is 
> forced upon them. This in my opinion is good, as it makes it easier to 
> reconnect erroneously disconnected tracks. So even when tracking zones 
> is included in DRC this behaviour is still useful.
I agree, I think the tracks not losing their nets, when they can't be 
reassigned, is far less surprising/disturbing to a designer.  It means 
you can be in the middle of a board edit, do a DRC, and then continue 
where you left off.

> I even think the proposed behaviour should be extended to net 
> conflicts: when a track is connected to multiple nets, the track 
> should keep its original net, so the DRC error will point to the 
> location with the problem, and not to some random location in the 
> middle of a track.
The patch would need to be extended to detect these "net conflicts", in 
theory it could be enhanced to maintain a list of such conflicts and 
also recover them at the end.  But I would propose adding that as a 
follow up patch if the behaviour I propose is accepted.
> It might be useful to list the unconnected tracks in the DRC besides 
> the unconnected pads, but that's only slightly related.
I can probably add this.  I haven't looked at what's required to add to 
the DRC message output/checking, but, in principle, a Message about the 
tracks which are unconnected to pads and were recovered could be 
generated during the processing where unassigned nets are recovered.

Perhaps there needs to be a DRC option to flag "Track not connected to 
Pad" and "Via not connected to Pad", as a Warning/Error.  Then, I could 
then flag them as required, during the net recovery part of my patch.  
The nets still wouldn't change their assignment, but DRC would then 
highlight that they are not connected to a Pad.  As it stands, the nets 
will change to unassigned and wont be highlighted unless that change 
causes another DRC error.

It would make the patch more complex, but would possibly make it more 
useful to a designer and help create better boards.

Steven