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

[John Doty <jpd@xxxxxxxxx>]

On Sep 12, 2010, at 9:09 PM, DJ Delorie wrote:

> If a cutout is a property of an insulating layer, the a drill through
> the whole PCB is really a composite of 2N+1 drills through N insulating
> layers and N+1 conductor layers.

I'll call that the "geometric" viewpoint.

> 
> That seems kludgy to me.  Drilling is a single operation, why do we
> have to represent it as multiple objects ?

I'll call that the "process" viewpoint.

Now, the question becomes "which is more fundamental?".  I think it's geometry.

1. I think that most designers essentially perceive the design geometrically.

2. Different processes may achieve that geometry by different paths.

3. The physical function of the board depends on geometry, not on the process by which that geometry is created.

So, I think that for the design process, the geometric viewpoint is more fundamental. That's the foundation that should support the designer's view. It should be the responsibility of the export function to translate that into a process-oriented description.

John Doty              Noqsi Aerospace, Ltd.
http://www.noqsi.com/
jpd@xxxxxxxxx




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