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Date: Thu, 10 Jul 2014 00:49:57 -0400
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From: DJ Delorie <dj AT delorie DOT com>
To: geda-user AT delorie DOT com
In-reply-to: <53BE0E7C.7050809@sonic.net> (message from Dave Curtis on Wed, 09
	Jul 2014 20:54:36 -0700)
Subject: Re: Layers and footprints (was: Re: [geda-user] pour clearing around
 pads)
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> It strikes me that this is an excellent layer model for talking about 
> footprint models, even though pcb doesn't support arbitrary symbolic 
> layers.  If we define a model consisting of symbolic logic layers, each 
> containing sublayers, and define rendering rules, then we can map what 
> pcb *currently* does onto that same model.
> 
> So while ultimately it would be great if users could create arbitrary 
> layer stacks with arbitrary names, and define their rendering order, 
> right now today pcb *has* a set of logical layers, with defined names, 
> and a defined rendering order.  That means one could go ahead and define 
> a footprint model around some future flexible layer model.  The 
> footprint file format can target the flexible layer model, its just that 
> if you code a footprint today there is exactly one layer model available 
> to you, with pre-defined layer names, so your footprint needs to live 
> within those constraints.  As pcb moves forward, more of the semantics 
> of the footprint model become available as layer constraints are relaxed.

I suppose we could start with a new footprint *import* format, and
support a subset of it, with the expectation that we'd support more of
it later.  I'd want to consider it "experimental" in case we end up
*not* supporting it later, or supporting something different.

Bonus if we could convert that format to Kicad too :-)