Eagle Autorouter hate?

[pyrohaz]

I have to ask, I use Eagle for all of my PCB's and I have a pretty darned old version (Windows 98 styled buttons in Windows 7 old...) and yet, I'm only ever doing 2 layer PCB's with SMD and through hole components. One thing I wonder is that nearly every single person rips into the Autorouter. I'm really just wonder why tbh. I always hand route critical paths such as USB, capacitive sensors or anything >1MHz by hand (plus audio). Otherwise, I quite happily (with customised settings) use the autorouter and it always does an acceptable job for me! I rarely have to change many of the paths or anything like that.

Why the hate?  O0

[zapta]

Otherwise, I quite happily (with customised settings) use the autorouter and it always does an acceptable job for me!

Same here. Critical nets by hand, rest (~80%) of the nets by the Eagle autorouter. I don't even bother to clean aesthetically.  Life is good.

Edit: I typically change the default autorouter settings,  5mil or 1mil grid, any angle routing on all layers. I rare occasion I also play with the optimization parameters, for example to increase the cost of routing in ground plan layers.

[Precipice]

Would you be able to dump a screenshot of an autorouted board?
(I long ago abandoned autorouters, but you guys are making it sound like I might be missing out)

[Wilksey]

I would suggest a newbie in PCB routing tries hand routing a few simple projects just to get the practice in, nearly all of the books i've seen for Eagle (or <insert your favourite package name here> for that matter) guides you though many chapters on the autorouter.

For everyday practicality and time, router the critical paths by hand then let the autorouter rip is what I say!

[zapta]

Would you be able to dump a screenshot of an autorouted board?
(I long ago abandoned autorouters, but you guys are making it sound like I might be missing out)

Here is one

https://github.com/zapta/power-monitors/blob/master/pmon_3v8/eagle/pmon_3v8_board.pdf?raw=true

Crystal and critical power nets routed manually. Everything else auto. The blue bottom layer is ground plane (printed without the fill in).

[Precipice]

OK, cool - thanks! (Was this Eagle?)
And I guess the second half of the question is - how long would that take you to hand route? (I assume the router takes essentially zero time?)
I'm also assuming that you still do the component placement entirely by hand, no autoplace to go with the autoroute, so placement time is the same for both approaches?

(I've just tried Altium's autorouter on a few boards I've done recently - it had a decent go at a couple, and I'm tempted to give it a try on a demo board I've got coming up, but the tighter boards, even simple ones, it just fails at. I could dig my Specctra license out, but I _know_ that's dimwitted)

[zapta]

OK, cool - thanks! (Was this Eagle?)
And I guess the second half of the question is - how long would that take you to hand route? (I assume the router takes essentially zero time?)
I'm also assuming that you still do the component placement entirely by hand, no autoplace to go with the autoroute, so placement time is the same for both approaches?

(I've just tried Altium's autorouter on a few boards I've done recently - it had a decent go at a couple, and I'm tempted to give it a try on a demo board I've got coming up, but the tighter boards, even simple ones, it just fails at. I could dig my Specctra license out, but I _know_ that's dimwitted)

Yes, that's eagle.

Placement and the manual routing of critical nets take most of the time (and may require iterations). I am also using the automatic router as a metric for quality of placement (do rough placement, do auto routing, examine the completion rate, number of vias, routs that do not make sense, undo the routing and improve the placement).

Auto routing may take some time (e.g. a minute or two), especially if you set fine auto router grid (default 50 is way too high, I use 5 or 1) but this is the fun part of all the layout process, you click a button and watch your work done. ;-)

[zapta]

Change the title from '!' to '?' ?   (since you are asking, not stating hate).

[FrankBuss]

Would you be able to dump a screenshot of an autorouted board?
(I long ago abandoned autorouters, but you guys are making it sound like I might be missing out)

A more complex example for which I used the autorouter: http://www.frank-buss.de/parallella/sampler/board.pdf Power lines routed by hand, then using the autorouter to do the rest. The board works fine. But I wouldn't use it for a production board, it just doesn't look as nice as a hand routed board, and Eagle can't route very dense boards, like this. But I do use it often the same way zapta says, as a metric for quality of placement. And the interactive "follow me" router mode in more modern Eagle versions is nice for manual routing.

[pyrohaz]

Change the title from '!' to '?' ?   (since you are asking, not stating hate).

Have done! Sorry about that.

Would you be able to dump a screenshot of an autorouted board?
(I long ago abandoned autorouters, but you guys are making it sound like I might be missing out)

A more complex example for which I used the autorouter: http://www.frank-buss.de/parallella/sampler/board.pdf Power lines routed by hand, then using the autorouter to do the rest. The board works fine. But I wouldn't use it for a production board, it just doesn't look as nice as a hand routed board, and Eagle can't route very dense boards, like this. But I do use it often the same way zapta says, as a metric for quality of placement. And the interactive "follow me" router mode in more modern Eagle versions is nice for manual routing.

That board looks pretty complex in parts! Did you modify quite a few of the routes as I never get anything other than 45deg routes for corners and I can see in your board that there are a couple of different angles.

OK, cool - thanks! (Was this Eagle?)
And I guess the second half of the question is - how long would that take you to hand route? (I assume the router takes essentially zero time?)
I'm also assuming that you still do the component placement entirely by hand, no autoplace to go with the autoroute, so placement time is the same for both approaches?

(I've just tried Altium's autorouter on a few boards I've done recently - it had a decent go at a couple, and I'm tempted to give it a try on a demo board I've got coming up, but the tighter boards, even simple ones, it just fails at. I could dig my Specctra license out, but I _know_ that's dimwitted)

Yes, that's eagle.

Placement and the manual routing of critical nets take most of the time (and may require iterations). I am also using the automatic router as a metric for quality of placement (do rough placement, do auto routing, examine the completion rate, number of vias, routs that do not make sense, undo the routing and improve the placement).

Auto routing may take some time (e.g. a minute or two), especially if you set fine auto router grid (default 50 is way too high, I use 5 or 1) but this is the fun part of all the layout process, you click a button and watch your work done. ;-)

Thats a very good point actually, I really put a lot of effort into placing my components for ease of routing and highest efficiency, finding the best compromise can really take up a fair chunk of your time, then setting the autorouter to do the rest is normally only a negligible amount of time, especially on my i7!

[FrankBuss]

That board looks pretty complex in parts! Did you modify quite a few of the routes as I never get anything other than 45deg routes for corners and I can see in your board that there are a couple of different angles.

The thick power supply traces are all routed by hand, and IIRC I forgot some signals, which I quickly routed by hand, because I used a 1 mil routing grid, for which it needed an hour or so. The autorouter doesn't use other angles than 45deg and 90deg.

[marshallh]

Eagle's autorouter is absolutely terrible.

The only reason it'd be worth using is because the handrouting system is also a complete joke.

After using an interactive push/shove router (or hell, even one that simply lets you adjust existing routes without horribly breaking things) you'll be able to bang out basically any board in short order by hand, and it'll be superior.

[zapta]

Eagle's autorouter is absolutely terrible.

Can you explain why you consider it to be terrible?

[Wilksey]

Interactive push and shove would be a great benefit, but I wouldn't say it was terrible, and manual routing is quite easy, I can't really see why people have issues with it, I can only think that people just prefer their existing tools, which is fair enough as you have spent so long with them.

[c4757p]

Eagle's autorouter is absolutely terrible.

Can you explain why you consider it to be terrible?

Because:

Eagle can't route very dense boards, like this.

That's a dense board, not a complicated board. It looks rather trivial to me, actually. If it can't do that, what good is it?

[FrankBuss]

That's a dense board, not a complicated board. It looks rather trivial to me, actually. If it can't do that, what good is it?

The Eagle files are here:

https://github.com/FrankBuss/kerberos/tree/master/eagle

The problem is the bus. Maybe I'm using the autorouter wrong, but Eagle doesn't route nice parallel traces for buses, but uses lots of vias instead and a very chaotic routing, and it can't finish it then in the end. Maybe some Eagle user could try it, I've read that the autorouter was improved in version 7 (I'm still using version 6). But don't cheat and don't let Eagle route signals on the ground and power planes (it's a 4 layer board)

[c4757p]

Autorouters are for large circuits with big buses. This is like a car that's only capable of driving on the living room floor - okay, cute toy, but do you really expect me to use it?

[zapta]

Autorouters are for large circuits with big buses. This is like a car that's only capable of driving on the living room floor - okay, cute toy, but do you really expect me to use it?

There are many products that I wouldn't use but it doesn't mean they are not useful for other people and other use cases.  It's not an all our l or nothing thing.

[zapta]

The Eagle files are here:

https://github.com/FrankBuss/kerberos/tree/master/eagle

The problem is the bus. Maybe I'm using the autorouter wrong, but Eagle doesn't route nice parallel traces for buses, but uses lots of vias instead and a very chaotic routing, and it can't finish it then in the end. Maybe some Eagle user could try it, I've read that the autorouter was improved in version 7 (I'm still using version 6). But don't cheat and don't let Eagle route signals on the ground and power planes (it's a 4 layer board)

Is it midi.brd?  It is fully routed. Do you have the version after the manual routing of critical nets and before final auto routing?

[FrankBuss]

Is it midi.brd?  It is fully routed. Do you have the version after the manual routing of critical nets and before final auto routing?

Yes, midi.brd. Disable all layers, enable just 1 and 16, then select all and ripup group will leave only the routing in layers 2 and 3 for the power supply. Then try to autoroute with just layer 1 and 16 enabled for the router. With routing grid 1 mil it manages 95%.

[FrankBuss]

Autorouters are for large circuits with big buses. This is like a car that's only capable of driving on the living room floor - okay, cute toy, but do you really expect me to use it?

I'm using Eagle since DOS time, so I'm familiar with all the quirks. But it is very good where it matters: a stable program, which didn't crashed once since I used it, unlike when I tried Altium Designer, which crashed twice the weekend I tried it. How can I trust a program which crashes? What if it silently changes some traces instead of crashing? And digital rule check worked all the time reliable, too in Eagle. I can create a board in a few minutes, create the gerber files and send it to the PCB manufacturer and can be sure that it comes back as I drew it (not necessarly working as I planned it ).

But I'm willing to change, if there is a better program, and not too expensive (my main profession is programming, not PCB design). The manual routing capabilities, the autorouter and the Eagle GUI in general is indeed from stone age. What program can you recommend?

[zapta]

Is it midi.brd?  It is fully routed. Do you have the version after the manual routing of critical nets and before final auto routing?

Yes, midi.brd. Disable all layers, enable just 1 and 16, then select all and ripup group will leave only the routing in layers 2 and 3 for the power supply. Then try to autoroute with just layer 1 and 16 enabled for the router. With routing grid 1 mil it manages 95%.

I think I know what the problem is. The eagle router needs special consideration when you allow it to add traces in a filled polygon because the traces can break the polygon ('collapse' as eagle calls it). This is exactly what happened here, the top layer has filled ground polygon and can have auto traces which results in non routed GND air wires due to the collapsed polygons.  What I typically do is to manually route the ground as a critical net which guarantees that the GND polygon will not collapse (all islands are connected).  Otherwise the auto router did pretty good in this case (I used top='/', bottom='\', grid=1) and achieved 100% and consistently decreases the via count as it went through the optimization process.

MY boards are typically two layers with bottom layer having ground plane + traces. As mentioned earlier I manually route the ground and sometimes I also increase the cost of traces in the ground plan layer to encouraging shorter traces there to improve plane connectivity. When autorouting is done I spot check the routing by highlighting nets using the 'eye' button and estimating the actual-length/ideal-length ration. So far it never disappointed me.

Edit: ia ma using eagle 6.5.0 on Mac OSX 10.9.4.

[pyrohaz]

Autorouters are for large circuits with big buses. This is like a car that's only capable of driving on the living room floor - okay, cute toy, but do you really expect me to use it?

I'm using Eagle since DOS time, so I'm familiar with all the quirks. But it is very good where it matters: a stable program, which didn't crashed once since I used it, unlike when I tried Altium Designer, which crashed twice the weekend I tried it. How can I trust a program which crashes? What if it silently changes some traces instead of crashing? And digital rule check worked all the time reliable, too in Eagle. I can create a board in a few minutes, create the gerber files and send it to the PCB manufacturer and can be sure that it comes back as I drew it (not necessarly working as I planned it ).

But I'm willing to change, if there is a better program, and not too expensive (my main profession is programming, not PCB design). The manual routing capabilities, the autorouter and the Eagle GUI in general is indeed from stone age. What program can you recommend?

I agree here, I've not had the opportunity to use Altium (considering it cost a ton) though I'd always be willing to learn. The main thing that attracts me to eagle is the general simplicity of using it. Once you get around some of its quirks (like using route instead of wire - not a particularly intuitive thing IMO), its really simple and you just create your schematic, place components and go!

I find that Altium just looks really complex!

[FrankBuss]

I tried Altium once (http://www.frank-buss.de/altium/). They offered a 60 day free trial some time ago. Maybe if you ask them, they will offer it again, or ask Dave if they don't want . But right, Altium is much more complex, would need some time to get used to it. It is used a lot in big companies for big projects, so maybe they can live with the crashes and it doesn't do any other bad things to your schematic. But too expensive for me as well.

[flyrod]

I've been trying to route a small BGA adapter board in 4-layers.  By hand I can get around 90% and the eagle autorouter gets about the same.  I'm on eagle 5.  Are the autorouters better in newer versions or in different software?  I saw this and thought it would be worth a try:

https://freerouting.org/freerouting/using-with-eagle

What I'm trying might be impossible.  Does anyone with newer software want to give it a try?  I can send the eagle board file.

[james_s]

You realize you've dredged up a 6 year old thread?

I've never seen anything from an autorouter that I would consider better than marginally acceptable and that's for boards that have all the critical stuff hand router. IMHO autorouters are a waste of time, primarily a trade show gimmick. There is no substitute for hand routing.

[Wilksey]

I think the later versions of EAGLE has a better auto router, and whilst you can get some relatively good results with a decent auto router setup they don't take a lot of design factors into account, clock line routing for example, so I wouldn't use the auto router for anything other than a quick simple board that you can't be bothered to route yourself, BGA chips tend to house some complex blocks, not usually something that pairs well with an auto router, so I would concentrate on the fan-out and see what you can get away with constraint wise from your board house and you might have to go to 6 layers, but you'd be better off routing by hand, try a few ways of running the traces, sometimes it just "clicks".

[flyrod]

Thanks for the comments.

The eagle manual says the autorouter is 100%.  Does this mean it can work as a test for whether it is even possible to route a board?  I agree that the results are pretty messy, but if it can actually route it with 500 vias then I at least know it's possible.  At this point I think the traces are too dense to route in 4 layers.

What is the strategy for hand routing a BGA part?  Try to get all the traces out from under the part radially then worry about connecting them where there's more room?

Again, would someone with new software be willing to open a file and run the autorouter?  To me it is not worth the time, money, and autodesk BS just to try this myself for a hobbyist project.  I see there are some PCB route/design ads on ebay.  Maybe I'll give that a try.

[Wilksey]

It is not 100%

I have EAGLE V7 before they moved to the Autodesk subscription model, and I keep it only because the company paid for the license and it is still useful for opening legacy designs without the newer bloatware of V8+.

Looks like the newer variant is bundled as part of Fusion 360, don't know if you can get a standalone version any more, but they do state a free trial on their site so perhaps you can download and try before committing to buy.

I don't know if it is the same as Altium's subscription where you own the license and just pay subscription costs for new versions or support or if the application will revert to a cut down "free / lite" version after the subscription has ended, but it's £438 (GBP) whatever that is in your currency for a year subscription to Fusion and Eagle by the looks of it, which isn't bad for both programs if that is the case, not sure what edition of Eagle you get if I click on Eagle subscription then it takes me to the Fusion page.
Is there just 1 Eagle option now? 

[1276-2449-1-ND]

I've noticed that IF all the ends of the components end up right on the grid (or a large multiple), then the autorouter routes beautifully. It has problems and starts doing weird stuff the farther parts move off the grid.

The autorouter is great for quickly figuring out part placement, but the manual tools are so easy and useful now (compared to when this thread was started) that it's kinda fun to route a board manually.

[Sylvi]

Hi
I design analog circuits and grounding in these is important, as are power routings. I only use 2-sided boards and mostly through-hole parts. I do not use the ground symbol and usually have an idea of how things need to be placed and connected on the board to satisfy the ground/power flow and trying to keep the signal path as straight as possible. So, I route everything by hand. I consider this to be part of the fun of laying out a board and the auto-router cannot possibly meet my requirements. It can only do the easy traces anyway and you are left with the "toughies".

I use an old version of Eagle 4.16r2 which is what the pro version used to be. I cannot ever go to a subscription - it just irks me when I can and do own the old version. I also have 6.3 and 7.something but do not use them.

Have fun

[mj3452]

EAGLE autorouter seems to make discontinuity to ground fillings by placing vias too close to tracks, so that ground is not filled between via and track, meaning ground current cannot flow.
I think possible solution is to use very large via pads during autorouting and make them actual size (like 0.3mm) afterwards. (Memorising years of use of EAGLE.)