Follow-me router settings

Daniel Nilsson wrote on Mon, 07 March 2011 14:38

but without creating DRCs.

That's really silly, downright irresponsible if you design boards for

anyone else.

DRC is a important part of the board design process.  Especially when

manually routing, you want something that verifies you didn't put two

tracks too close together, copper too close to the board edge, maybe even

accidentally have two tracks cross, etc.

Also, you don't create a DRC.  There are always some DRC settings.  The

only question is whether they match your desired design rules or not.  Some

of these DRC settings aren't just for error checking either, they effect

the resulting copper.  Examples are thermals, minimum annulus, and lots of

others.  You are using some DRC settings all the time, whether you

explicitly set them or not.

Quote:

The follow-me router seems to be a good choice for what I'd like to do,

but I have not been able to figure out good settings that will allow me

to lay out the traces the way I want them but only use the follow-me

functionality in order to be able to "hug" other traces or route as close

as possible to a pad for

example.

Did you even look at the router settings?  There is such a thing as a

"hugging" parameter.

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On 03/08/2011 07:42 PM, Olin Lathrop wrote:

Daniel Nilsson wrote on Mon, 07 March 2011 14:38

>> but without creating DRCs.

 

That's really silly, downright irresponsible if you design boards for

anyone else.

Since this was my first post to the forum I'm surprised by this

unfriendly tone. I think you actuallt misunderstood my question, after I

setup the clearance rules from the PCB manufacturer I want to use the

follow-me router when doing manual routing in such a way that the

artwork is not violating any rules (i.e. not causing any DRC errors).

This is achieved with the follow-me router since it doesn't allow the

artwork to cause DRCs errors, this is what I want by I'm looking for

good settings for the follow-me router. The default rules have cost

associated with all kinds of things such as steps and changing

directions. It's not obvious which mix of costs and routing grid works

best here.

Quote:

>> The follow-me router seems to be a good choice for what I'd like to do,

>> but I have not been able to figure out good settings that will allow me

>> to lay out the traces the way I want them but only use the follow-me

>> functionality in order to be able to "hug" other traces or route as close

>> as possible to a pad for

>> example.

 

Did you even look at the router settings?  There is such a thing as a

"hugging" parameter.

Yes of course, along with the manual and the tutorial. I turned to this

forum for some best practice since this wasn't covered in any of these

documents.

Daniel nilsson <no-mail@nowhere.org> wrote:

Since this was my first post to the forum I'm surprised by this unfriendly tone.

Dont mind Olin. He has a long history of harshness to people that didnt

rtfm word by word.

Daniel Nilsson wrote on Tue, 08 March 2011 14:52

Since this was my first post to the forum I'm surprised by this

unfriendly tone.

You were asking how to do something irresponsible.  Not wanting to "create"

DRC settings is like not wanting a compiler to ever do type checking.  I

have little interest in helping people do dumb things like that.

Quote:

after I setup the clearance rules from the PCB manufacturer

But that IS setting up the DRC.

Quote:

I want to use the follow-me router when doing manual routing in such a

way that the artwork is not violating any rules (i.e. not causing any DRC

errors).

Then in addition to the proper DRC settings, you also need to set up the

autorouter.  Some settings in there are global, but there is also a tab

specific to the follow-me router.  Did you look at the hugging parameter I

already mentioned?

--

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On 03/09/2011 01:39 PM, Olin Lathrop wrote:

Daniel Nilsson wrote on Tue, 08 March 2011 14:52

>> Since this was my first post to the forum I'm surprised by this

>> unfriendly tone.

 

You were asking how to do something irresponsible.  Not wanting to "create"

DRC settings is like not wanting a compiler to ever do type checking.  I

have little interest in helping people do dumb things like that.

As I said earlier, you are not getting the question. I have never stated

that I don't want to create DRCs settings, the phrase "without creating

DRCs" refers to not creating DRC violations. Maybe you shouldn't be so

sure that the person in the other end that you have never met is an

idiot and the question is dumb before you are sure you understand

exactly what the person is asking for. If you think the person is asking

something stupid then you don't need to answer the question.

Quote:

>> I want to use the follow-me router when doing manual routing in such a

>> way that the artwork is not violating any rules (i.e. not causing any DRC

>> errors).

 

Then in addition to the proper DRC settings, you also need to set up the

autorouter.  Some settings in there are global, but there is also a tab

specific to the follow-me router.  Did you look at the hugging parameter I

already mentioned?

Yes, I did. But there are a total of 15 cost settings under the

follow-me tab, plus 3 maximums. In addition to this I think the grid

plays an important role. What I'm asking for are some "best practice"

from the people using the follow-me router on how to setup these

parameters. Just playing with the hugging parameter is not giving me the

result I want.

I tried the follow-me mode on one of the tutorials, singlesided.brd and

there it works a lot better using the default settings of that design.

One big difference though is that on the tutorial board every pin of

every component is on the routing grid. That is certainly not the case

on my designs, I don't think many other real world designs would be able

to achieve this either. However, the follow-me router still decides to

add vias when a trace is going diagonally. This is decision I'd like to

make on my own, so I assume I need to reduce the cost in the settings

for some of the step parameters or simply make adding a via very costly?

The original question was also on how to add a via manually when using

the follow-me router?

/Daniel

On 3/10/2011 3:17 PM, Daniel Nilsson wrote:

On 03/09/2011 01:39 PM, Olin Lathrop wrote:

>> Daniel Nilsson wrote on Tue, 08 March 2011 14:52

>>> Since this was my first post to the forum I'm surprised by this

>>> unfriendly tone.

>>

>> You were asking how to do something irresponsible. Not wanting to

>> "create"

>> DRC settings is like not wanting a compiler to ever do type checking. I

>> have little interest in helping people do dumb things like that.

 

As I said earlier, you are not getting the question. I have never stated

that I don't want to create DRCs settings, the phrase "without creating

DRCs" refers to not creating DRC violations. Maybe you shouldn't be so

sure that the person in the other end that you have never met is an

idiot and the question is dumb before you are sure you understand

exactly what the person is asking for. If you think the person is asking

something stupid then you don't need to answer the question.

 

>> Quote:

>>> I want to use the follow-me router when doing manual routing in such a

>>> way that the artwork is not violating any rules (i.e. not causing any

>>> DRC

>>> errors).

>>

>> Then in addition to the proper DRC settings, you also need to set up the

>> autorouter. Some settings in there are global, but there is also a tab

>> specific to the follow-me router. Did you look at the hugging parameter I

>> already mentioned?

 

Yes, I did. But there are a total of 15 cost settings under the

follow-me tab, plus 3 maximums. In addition to this I think the grid

plays an important role. What I'm asking for are some "best practice"

from the people using the follow-me router on how to setup these

parameters. Just playing with the hugging parameter is not giving me the

result I want.

 

I tried the follow-me mode on one of the tutorials, singlesided.brd and

there it works a lot better using the default settings of that design.

One big difference though is that on the tutorial board every pin of

every component is on the routing grid. That is certainly not the case

on my designs, I don't think many other real world designs would be able

to achieve this either. However, the follow-me router still decides to

add vias when a trace is going diagonally. This is decision I'd like to

make on my own, so I assume I need to reduce the cost in the settings

for some of the step parameters or simply make adding a via very costly?

 

The original question was also on how to add a via manually when using

the follow-me router?

 

/Daniel

Hi Daniel,

I hope you are doing well. The "Best Practices" when it comes to EAGLE's

autorouter is to use the default cost factors, that's the truth. Have

you tried looking through section 7.6 of the EAGLE manual? It details

every cost layer and how they affect the routing process, it also gives

recommended values. The EAGLE manual is included with the EAGLE

installation in PDF format. If you're a windows user the easiest way to

get to it is from the Windows desktop. Start-> All Programs-> EAGLE

Layout Editor-> Manual.pdf. If you're not a Windows user then you'll

find the manual in the doc folder for the EAGLE installation folder.

You'll find the routing grid setting in the General tab of the

Autorouter settings, by default it's set to 50 mils but a more practical

value would be in the 5-10mil range, EAGLE can go as fine as 2mils. The

manual states that for the follow-me autorouter the working grid IS the

routing grid, so set your working grid to something in the 5-10 mil range.

As a final note you can't manually add a via when using the follow-me

router, the autorouter automatically calculates the via locations. If

you want to manually lay down vias then you need to manually route the

specific trace.

hth,

Jorge Garcia

P.S Like Morten said don't mind Olin, he can be a little cranky

sometimes. You'll find that most of the members of the forum including

Olin are more than happy to help, and the forum is very active.

Daniel Nilsson wrote on Thu, 10 March 2011 15:17

the phrase "without creating DRCs" refers to not creating DRC

violations.

That could definitely have been expressed better.

Quote:

Maybe you shouldn't be so sure that the person in the other end that

you have never met is an idiot and the question is dumb before you are

sure you understand exactly what the person is asking for.

Maybe you shouldn't get so upset when someone interprets a poorly worded

question in a way that wasn't intended.

Quote:

If you think the person is asking something stupid then you don't need

to answer the question.

Pointing out something is stupid can be useful.

Quote:

Yes, I did. But there are a total of 15 cost settings under the

follow-me tab, plus 3 maximums. In addition to this I think the grid

plays an important role. What I'm asking for are some "best practice"

from the people using the follow-me router on how to setup these

parameters.

I don't use the follow me router much.  It sounded like a good idea at

first, but I haven't found it all that useful.  When you're manually

routing, it's usually because you want traces to have a specific layout,

like to contain high currents of a switching power supply, make a short and

direct connection between a microcontroller and its crystal, etc.  In those

cases, the follow me router does too much stuff on its own I don't want.

For other traces that just need to get from one place to another but aren't

critical, I don't need to be envolved at all and can use full auto

routing.

You do need to tweak the auto router settings according to what you are

trying to accomplish.  When I first started using the auto router, I found

the default settings pretty useless.  You have to go thru the manual and

understand what each setting does, and play around with it to get some

intuition on what effects it causes.

Quote:

Just playing with the hugging parameter is not giving me the

result I want.

OK, so play around with some other parameters.  Again, you really need to

understand and get some intuition about all the parameters.  It takes more

work to learn to use the auto router well than for manual routing, but in

the end it's a nice tool that can take care of a lot of drudge work for you

if you use it right.

Quote:

However, the follow-me router still decides to add vias when a trace is

going diagonally. This is decision I'd like to

make on my own, so I assume I need to reduce the cost in the settings

for some of the step parameters or simply make adding a via very costly?

Don't assume, know.  Read the manual.  There are settings for the cost of

diagonal steps, vias, and lots of other stuff.

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