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Re: gEDA-user: Functional blocks and PCB format changes
Hi Rick,
> -----Original Message-----
> From: geda-user-bounces@xxxxxxxxxxxxxx
> [mailto:geda-user-bounces@xxxxxxxxxxxxxx] On Behalf Of Rick Collins
> Sent: Sunday, September 05, 2010 12:38 AM
> To: gEDA user mailing list
> Subject: Re: gEDA-user: Functional blocks and PCB format changes
>
> At 11:49 AM 9/4/2010, you wrote:
> >On Sat, Sep 04, 2010 at 01:16:01AM -0400, Rick Collins wrote:
> > >
> > > Don't hold back, tell us how you really feel!
> > >
> > > The spec is large because it addresses a wide range of design
> > > aspects, which is one of the great reasons for using it, one file
> > > for the entire design, schematic, layout, mechanical, etc, even
> > > board lay up. So the compatibility issue is moot because any one
> > > app only needs to deal with the portion that applies to it. Just
> > > don't muck with the other parts.
> > >
> > > The "heavy" issue is a red herring (are you planning on
> hosting this
> > > on a cell phone maybe?) No PCB file format is going to
> be easy for
> > > humans to read. Bandwidth? Back to the MCU in the cell phone I
> > > guess. "Ugly", now there is a great technical argument.
> > >
> > > But I suppose it is better to re-invent the wheel. There is no
> > > reason to try to foster any sort of compatibility in file formats
> > > between all the different CAD tools. There are always conversion
> > > programs to be written, no?
> > >
> >
> >This is not an emotional argument, but a technical one, and
> the choice
> >is not between XML and reinventing the wheel. (Sadly, my Lisp
> >suggestion has been shot down - by better arguments than
> popularity, I
> >might add. ;) There are other formats to consider, and yes,
> inventing
> >one might be an option.
> >
> >How do you know PCB won't ever run on cell phones, or over a slow
> >network link, or on an embedded device or network PC or overtaxed
> >virtual machine? How do you know we won't one day need to work with
> >1000-layer boards when suddenly it /does/ matter how heavy the file
> >format is?
>
> So are you suggesting that we should, at this time, plan for
> running PCB on a cell phone? Do you want to design PCB to
> work on overtaxed virtual machines, if so, I expect there
> will be a lot more important things to optimize than the file
> format which only impacts the performance when reading or
> saving the file. If we need to work with 1000 layer boards,
> I expect we would have computers which would be not at all
> burdened by XML file formats.
>
> I'm trying to be realistic about the requirements. I think
> that the 2x or 3x factor of file size of using something like
> XML would be lost in the noise. The advantages of working
> with an industry standard file format could be very large.
> Of course as you or someone pointed out, IPC-2511B is not a
> well established format. But to my knowledge it is the only
> one that spans most if not all aspects of circuit board
> manufacturing. It seems like a great idea to work with
> something this useful and I am pretty sure that concerns with
> using it can be ironed out.
>
>
> >Unless you want feature-parity with other CAD programs, it is
> >impossible to have file-format-parity. So no matter what, conversion
> >programs will have to be written. Creating similar file
> formats won't
> >help anything, other than to limit our own format, and potentially
> >cause problems if PCB and another CAD program are able to open (and
> >corrupt) each other's files.
>
> I don't agree that a common file format has to be
> restrictive. If the file format is flexible enough, the
> program won't be limited. Everything doesn't have to be
> included from the start. I don't know if IPC-2511B is
> flexible enough for PCB and future ideas for PCB, but using
> XML I expect it can be expanded easily. I don't think anyone
> here has really looked hard at it. It may well be
> extensible. I don't know. But I would like to at least
> consider it and not toss it away without giving it a chance.
>
> Rick
>
>
IMHO, the "problem" with XML lies not in the bloat, even a factor 10 larger
would be acceptable, it's the <$TAGS> that have to be identical across all
applications to have a "truly" exchangable XML file.
I think that for an exchangable format for schematic capture, pcb layout
__and__ 3D mechanical CAD stuff the "problem" is waaay to big to grasp in a
forthnight and DIY.
And there happens to be a standard of sorts which does just that, named IDF,
some of the large commercial CAD vendors play this game already.
In this playfield design files with 1MB < size < 10MB is not that uncommon
these days.
Welcome in "Utopia" mate ;-)
Have a look at:
http://www.simplifiedsolutionsinc.com/images/idf_v40_overview.pdf
http://www.protel.com/files/training/Module%2020%20-%203D%20Mechanical%20CAD
.pdf
http://www.simplifiedsolutionsinc.com/images/idf_v30_spec.pdf
Happy reading ;-)
Kind regards,
Bert Timmerman
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