kicad-developers team mailing list archive

["Simon Huwyler" <simon.huwyler@xxxxxxxxxx>]

After sleeping over it, I see the whole thing a little bit differently. In contrast to what I always said about how layer-based constraints should work (in terms of UI), I now think, that, while my approach is perfect for my problem to solve, it may, as you folks said, not be perfect for other users. I learned that these layer-dependent manufacturing constraints are quite unusual, and the well-known way to handle layer-based constraints, the way specctra does it, appears to be more complicated to solf my problem, but is on the other hand WAY more flexible. And it appears to be the standard.
Then, a layer based constraint is often motivated by impedance matching. And from this point of view, it must be connected to the net class, of course.

Now, still another thing: It’s been a while when I was working with Protel (now Altium designer), but I mean to remember that there you could enter three different widths: A minimal, a maximal and “standard”. This seems to be a good thing to me, because it is normally a bad idea to always stress the constraints to the limit, because of the yield.

So, why not implement this also? And how about clearance? Standard vs minimal clearance (max doesn’t make sense). Normally KiCad guides you to keep the standard clearance, but you may reduce the clearance. This is not quite as easy as the “standard width<—>minimal width” feature in terms of how to present the feature to the user, but, it may still bee very cool.

>From the technical point of view, I was quite surprised how easy it was to implement what I implemented. Of course I know about the 80-20 roule, but I certainly have 80% of functionality implemented, therefore 20% time effort. –> Very cool things are very well achievable!

Maybe “layer based constraints” is not any more a good term, but I would really like to start a blueprint on this. Maybe called something like “constraint system” or so...?

I just think that now that There will be the push-n-shove router, KiCad becomes even more sophisticated, and I think the constraint possibilities become too limited compared to the overall project features.

uh, another thing, I think this has also been mentioned before: It should be an absolute must to be able to define net classes in eeschema. I think, from the technical point of view, this should be easy.


But I’m still not quite sure about where I, you, we stand about the motivation to do something like this. I have the impression that there is a reluctance in accepting new features at the moment because the main effort is based on getting/keeping the whole package stable and consistent. I myself woul be very eager to help implementing such a thing, but if it is just the wrong time now, I would understand that, of course.
On the other hand, if you folks don’t think there should be an improvement on the constraint system at all, then I disagree but – of course – accept that, too.  Even so, KiCad is great!

And then, I must admit, that I have absolutely no “hands-on-experience” in working for an open-source project and I have no clue about the “work-flow”. I had the somewhat naïve impression that everyone could just contribute something and everyone was happy to take it. Of course this would lead to a complete mess.  

Greets
Simon

From: Dick Hollenbeck 
Sent: Wednesday, May 08, 2013 4:09 AM
To: Simon Huwyler 
Cc: KiCad Developers 
Subject: Re: [Kicad-developers] layer based constraints

Load source specctra_import.cpp.

In the comments near the top, look for specctra.pdf.  tells where.

On May 7, 2013 6:20 PM, "Simon Huwyler" <simon.huwyler@xxxxxxxxxx> wrote:

  A short google consultation showed me this:

  SPECCTRA FOR ORCAD AUTOROUTER
  SPECCTRA for OrCAD is well known for its
  comprehensive feature set. The extensive rule
  set can control a wide range of constraints
  from default board-level rules to rules by net
  and net class.


  "default board-level rules" sounds to me like something like this.
  But unfortunately I didn't find anything yet, and since it's twenty past one I'll call it a day for now. :-)

  Dick, could you tell me where I can find this pdf? Thanks!

  -----Ursprüngliche Nachricht----- From: Simon Huwyler
  Sent: Wednesday, May 08, 2013 1:09 AM
  To: Dick Hollenbeck
  Cc: kicad-developers@xxxxxxxxxxxxxxxxxxx
  Subject: Re: [Kicad-developers] layer based constraints


    Page 17 of the specctra.pdf file I sent you a couple of weeks ago shows the
    class_descriptor.


  What PDF file? I didn't get any. But of course I should find some
  information about this.


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