Ken Patel wrote:
>
> Design Guru,
> Does complete database file in Cadence Allegro contain all information
> necessary to recreate the design (i.e. parts geometries)? I am interested in
> knowing this as we depend on third party for design layout.
>
> I think it does but someone asked me specifically which I can not answer
> with authority as not my area of expertise.

        Hi, Ken -

        Allegro databases are *largely* self contained, but
        there are a couple pieces of external information needed
        for some functions.

        All library type elements such as component geometries
        and pad descriptions are indeed self contained.

        Items such as special pad flashes are not, however, if
        one's destination is RS-274X.  These remain as a part of
        the library and never actually get read into the Allegro
        .brd file - they are only pointed to inside the database
        and are only read by the "artwork" program.

        Perhaps this relates to your other thread on missing data
        in a 274X file; we usually set our gerber output parameters
        top stop executing on error, but perhaps by continuing to
        execute you can make gerber files that lack the special
        symbols (commonly thermal reliefs or doughnut pads), I am
        not certain and I don't have data to test at hand.

        This condition would be analogous to a RS-274D file with
        no description for the special flashes.

        If you could get the file "photoplot.log" that was made
        during artwork creation this would list all the error con-
        ditions and also the parameters the files were created with.

        Good luck,

--

      Jeff Seeger                         Applied CAD Knowledge Inc
      Chief Technical Officer                  Tyngsboro, MA  01879
      jseeger "at" appliedcad "dot" com                978 649 9800

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