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Re: gEDA-user: Layer selective DRC



Andrew Poelstra wrote:

>> The procedures with no_drc look unchanged. I still don't see a way 
>> to make this work. I give up and write a bug report. 
>>
> 
> :( 

Of course, I still have to satisfy the design rules of my fab. My board
is 100 µm copper on inner layers and 35 mm on outer. The fab requires 
0.25 mm minimum distance for this thick copper. On the other hand, the
board is densely populated on the top. So I need at least 0.20 mm design
rule there. 
Unfortunately, I didn't realize in advance that there are different 
design rules in effect. So I did my routing with 0.20 mm and believed, 
I was on the better side. The fab promptly complained and stopped the 
job. If minimum distance is set to 0.25 mm, DRC takes almost forever and
comes back with a few thousend violations.

In this situation, the ability to let DRC ignore selected layers would 
solve the task. Too sad, that I did not get this brave new feature to work
properly. I tried to temporarily remove the tracks from top and bottom. 
Unfortunately, this renders many vias unconnected, but very close to pads. 
This swamps DRC output, again. In addition, I'd loose the ability to check 
for connectivity.

Finally I settled for a dirty hack: Divide the line witdh of all tracks on 
top and bottom by 10. Then push tracks on inner layers to satisfy the 0.25 mm 
rule. When done, multiply track width by ten to render the top (almost) like
it was. Linewidth manipulation is done with the attached gawk script. 

---<)kaimartin(>---
-- 
Kai-Martin Knaak                                  tel: +49-511-762-2895
Universität Hannover, Inst. für Quantenoptik      fax: +49-511-762-2211	
Welfengarten 1, 30167 Hannover           http://www.iqo.uni-hannover.de
-----> not happy with moderation of geda-user mailinglist

Attachment: set_linewidth.sh
Description: application/shellscript


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