Allow track with to shrink to go between pins?

[DaQue]

Is there a way I can have the push shove router lay out 15 mil traces unless it needs to go to 6-9 ish to sneak between pins/pads while respecting minimum spacing?

[craftyjon]

This is called “automatic neckdown” and is a feature we want to add in the future, but it doesn’t exist today.

[DaQue]

Thanks. I guess I could route it using a smaller track with then expand the rest of the track.

[aaron]

It depends on what you are looking for. I have run into this with escape routing under BGAs. With the 5.99 Nightlies, there is now a more sophisticated area-base DRC rule engine that can handle this I believe.

Need some guinea pigs for a rule-based DRC <<PROTOTYPE>>

First the small text: the rule syntax WILL CHANGE. What’s there today is a PROTOTYPE. There will be NO TOOLS for migrating today’s rules to later rules. Think of it as a sandbox, not a work-in-progress. But I’d still like to get some feedback on what it does well, what it does poorly, and what is missing. If you’ve never use a nightly, our built from scratch, this probably isn’t for you. But if you have… The rules go in a file in your project named “drc-rules”. You can edit them there in…

With 5.1 and prior here was my work around (which is a bit of a pain):

1. Set the netclass rules smaller specs
2. Route out under the BGA to the edges
3. Run the DRC
4. Set the netclass rules larger specs
5. Route out route the rest
6. Run the DRC, ignoring the flags that were already checked.

[paulvdh]

The quickest way to do it manually is:
Pcbnew / File / Board Setup / Design Rules / Tracks & Vias / Pre-defined track and via dimenstions

Then add some track widths you want to use (so for example 15mil and 8 mil in your case), and then after that you can switch with hot keys between the thicker and the narrower track in that list (you can have multiple widths).