> Here's a list of layers we probably > > want to support, from top to bottom: > > > > DRC layer > > top keepout layer > > drill (maybe support more than one drill layer to allow for e.g. > > plated vs. non-plated holes) > [jg]These first three don't fit DJ's proposed physical mapping of layer > purposes to physical > board layers.
That's OK. The idea is that each layer corresponds to one output CAM file, or at least to a layout tool concept. Therefore: * The drill layer produces a drill file (Excellon) which is read by the corresponding CNC drill machine. * The keepout layer is a concept borrowed from other layout tools which need someplace to hold this info in a footprint, and do so by assigning keepout info to a layer in the padstack. * The DRC layer is independent so that it may be turned on and off, the color may be changed, etc. I guess one might also produce a Gerber from the info contained on the DRC layer. Would this info be useful at some point in the manufacturing or CAM process? Maybe to flag potential tight spots to the guy doing the CAM job? I dunno..... > > outline (& other mechanical notations) > [jg]goes on "ink layer"? > > top silkscreen > [jg]goes on "ink layer"? Personally, I think these should remain separate. The outline layer is a mechanical layer which tells the fab house how to route out the PCB. The silkscreen layer tells the fab house where to put the white lettering. They're totally separate functions, and should be held in separate files. Cheers, Stuart _______________________________________________ geda-dev mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-dev
