Re: gEDA-user: next PCB release - 1.99za vs 4.0

[John Griessen <john@xxxxxxxxxxxxxx>]

On 09/12/2010 10:09 PM, DJ Delorie wrote:
> I'm thinking we structure the layers into "composites".  Each
> composite contains some conductor/insulator layers, including other
> composites, and an overall shape (outline, drills, slots).
>
> Thus, a drilling operation is stored as a single "drill" object in the
> composite's outline layer, and buried vias are just drills on a
> sub-composite.
>
> The heirarchy of composites represents the manufacturing process, so
> implicitely defines the possible blind and buried vias - you either
> drill through a composite or you don't.  If a composite happens to
> represent copper layers 4 and 5 and the insulator between them, you
> get a buried via.  If the composite is layers 0 and 1, you get a blind
> via.  If it's the top-level composite, you get a regular via.  Etc.


I think that idea handles John D's worry that insulators are well defined.

DJs idea the other day of using a side program to iterate through a list of
objects and attributes to generate  specific CAM outputs could handle any
want to go deeper toward primitives such as insulator layer with holes in it
considered separately from it surrounding conductors and being bonded together.

John G

--
Ecosensory   Austin TX


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