Hi Rick, > -----Original Message----- > From: [email protected] > [mailto:[email protected]] 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 _______________________________________________ geda-user mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
