Is there a method to have Kicad Pcbnew autoroute just a single net? When in OpenGL mode, right clicking provides an “Automatically Route All Footprints” selection. I know from reading the forums, there are many strong opinions against auto routing. However, it would be great if one could simple autoroute the power and grounds at the start, or any other single net. Is there a way to do this?
Why do that? Use CERN router, you will do it in one second. It is automatic, you only move mouse in general direction of the pad. Two clicks, you are fine…
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Thanks for the feedback, but not what I’m after.
I think I understand @CktMaker idea.
Click let’s say VCC and autoroute.
Well, it is not very a good idea.
You must take care to route power supply tracks very carefully, place decoupling capacitors carefully, make the track short and then you can proceed to other nets. Ground is really automatic with groundplane and zones.
Even If I had decided to use autorouter, I’d first place components, run power, ground plane manually and lock them.
However, still the new CERN router will run circles around autorouter.
Greetings,
Tom
Tom, Thanks your argument for manually routing power and grounds make good sense. As someone mentioned in another forum topic, the autorouter can be useful as a ‘learning tool’ to guide you to where to place and orient components. In my case, I was starting a fresh board and wanted to see where the auto router would have placed the power and ground. Same goes for a track/net later in layout - wanted to see what the auto router would do.
Help me understand (and the rest of the readers 
) what you are referring to when the new CERN vs autorouter. Am I correct in saying that the CERN is the “interactive router” accessed in the OpenGL or Cairo canvas mode vs. the Autoroute access in the default canvas mode?
Hi
Routing a pcb is part science, part art. More art. Basically, first, you need to take care of the Power supply. It is most important. Why so? The processor and all digital chips are err… digital. They switch from 0 to 1, or from no current/no voltage to full voltage pretty fast. They generate lots of noise this way, harmonics, peaks and all those bad things come back to the circuit doing all kinds of disturbance. Your scheduled workflow much cope. Hence, some thinking how to avoid the disturbance is needed. Even in quiet environment without any external sources of noise, you own workflow will create noise. This is why you have to supply stable current to your digital chips. The processor doing simple on/off draws a lot of current. I am not talking automotive environment, just normal, quiet, standard stuff. How you cope?
There are 4 major points:
- Your tracks must by as short as possible - they are little antennas, so, keep them short - power and digital.
- You bypass capacitors must filter the noise, so the must be very, very close to the Vcc pins.
- They must react fast, so ESL and ESR must be small, when you look at their equivalent circuit, they must filter out all possible shocks, otherwise the processor will reset.
- The loops created by Vcc and ground must be short, the best way is to make ground plane. Separate, huge topic.
The software know nothing about those considerations, how can it route properly?
I advise to read this short document, a real eye opener, how to design the power supply in your circuits.
This short doc is better learning tool than any autorouter, I think.
Of course, there are different and additional considerations in analog circuits.
CERN router allows to route tracks very quickly, but you use your intelligence. Autorouter tries to do all tracks, using spatial, or topological optimization. I prefer to do my own, and learn from my mistakes 
I am just a hobbyist, I hope real experts will tune in !! Good thing is, this forum is the most friendly one I know!!
Greetings,
Tom
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You can either push you existing tracks and vias around, (magic) or track go around existing ones (magic) You really don’t have to look very closely what is going on, like in other design tools. Much easier on the eyes… The third option is just show DRC violations, I had no opportunity to use it.