I was having a lot of trouble routing a tightly packed board as a two layer board, even manually, so just for a test I thought i would turn the auto router loose on it as a 4 layer board. I set the DRC up as (12+1516) . Ont eh auto router dialog, I told layers 1,2, 15 and 16 to use *, and I think 6 vias per trace.
I started the job running over 8 hours ago and its still running. Its on the optimize 4! This is on a quad core i7 with 6 gigs of ram. Perhaps I have done something wrong to confuse it? This can’t be normal can it? It run 2 layer (with ~45 air wires) in under an hour or so.
leon_heller:
The Eagle autorouter doesn’t have a good reputation.
True, but 8 hours?
Is there an alternative router? I know there is a web site, freerouting.net I think, that accepts files generated by Eagle. What happens when it is done? Can the output of another router be imported back into Eagle?
Oh I downloaded Electra. Once I export the dsn (I think dsn) file and run it, is it possible to get the results back into Eagle for hand touch up or gerber generation?
jarcher:
Is there an alternative router? I know there is a web site, freerouting.net I think, that accepts files generated by Eagle. What happens when it is done? Can the output of another router be imported back into Eagle?
Yep it can - there are good instructions on their website - it just outputs a script that you save, and when you run the script in Eagle BAM the tracks are there.
jarcher:
Is there an alternative router? I know there is a web site, freerouting.net I think, that accepts files generated by Eagle. What happens when it is done? Can the output of another router be imported back into Eagle?
Yep it can - there are good instructions on their website - it just outputs a script that you save, and when you run the script in Eagle BAM the tracks are there.
That’s very cool. Electra is quite expensive, but if it can route this board it might just be worth the price.
Eagle finally finished after 10 hours. It had exactly the same number of air wires as when I routed it as a 2 sided board - 43. And it is mostly GND connections, just as with the 2 layer board. But having the extra two layers will make it easier to manually correct the air wires. Still, I thought Eagle could easily route it given all the extra space available.
You can download Lite version of it, which has a few limitations: 8 signal layers, 125 nets or if your board is not a top secret, I could make the routing and provide you with details of how long it took for both autorouting and manual editing.
Your project sounds interesting as TopoR is very efficient on doudble layer boards, so it would be a challenge :D](http://www.eremex.com/)
Traditionally, with a 4-layer board, you reserve the inner two layers for Vcc and GND planes. In addition to making a quieter board, that saves the need of separately routing those traces.
I don't think EAGLE is multithreaded; your extra cores don't help :-(
(It’s a feature I’d like to see. Except that most of EAGLE isn’t CPU bound, anyway. And trying to imagine how to multithread a PCB autotouter makes my brain hurt!)
-TopoR-:
I could suggest [TopoR (topological router).
You can download Lite version of it, which has a few limitations: 8 signal layers, 125 nets or if your board is not a top secret, I could make the routing and provide you with details of how long it took for both autorouting and manual editing.
Your project sounds interesting as TopoR is very efficient on doudble layer boards, so it would be a challenge :D[/quote]
Its not top secret, may i still accept this generous offer? I don’t think 125 nets would be sufficient :-(](http://www.eremex.com/)
-TopoR-:
I could suggest [TopoR (topological router).
You can download Lite version of it, which has a few limitations: 8 signal layers, 125 nets or if your board is not a top secret, I could make the routing and provide you with details of how long it took for both autorouting and manual editing.
Your project sounds interesting as TopoR is very efficient on doudble layer boards, so it would be a challenge :D[/quote]
Its not top secret, may i still accept this generous offer? I don’t think 125 nets would be sufficient :-([/quote]
Thank you Elana! She and TopoR did a great job routing my board. Its very interesting. Its as much art as engineering. Tomorrow, I’ll make another thread with some more thoughts and some pictures. But for now, my first thoughts when I opened it were that it looked cool, but could not possibly be fully routed. There seemed to be too few traces and vias. But it is fully routed, and its amazing how little trace length there seems to be.
