On Mon, Sep 06, 2010 at 11:24:58AM -0600, John Doty wrote: > > Choosing the right level for the primitives is important. I wouldn't drop > below a "planar stack of geometric shapes" here. But I wouldn't go higher > for primitives either. One might very well wish to draw arbitrary shapes > in silk, or one might require holes of arbitrary shape. I once worked with > a board that had different numbers of layers in different places, and with > different conductive materials for different traces (not designed with pcb!). > A well-factored design should be able to express this kind of thing. > > A format that would be equally at home specifying the layout of a printed > circuit board, a VLSI chip, or a Mondrian painting would be a good target. > I don't think we need to go as far as spherical circuits or Picasso ;-). >
Sounds good. But I'm worried that by dropping down to basically a vector drawing, we're going too far. However, given that any decent file format will let us create PCB objects from geometric shapes, perhaps this is an unjustified fear. > > ... > > It's often necessary to align shapes on different layers: that's not a > special property of vias. So, the machinery of composition of objects from > more primitive objects needs to be able to control that. Then it would make > sense to use that machinery to compose vias. The reason we can't have blind > and buried vias is a consequence of the lack of such factored, orthogonal > design in pcb at present. > This is a very good point. I agree with it. Andrew _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user