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Re: gEDA-user: An idea: rework design support...

On May 14, 2011, at 4:47 PM, Peter Clifton wrote:

> On Sat, 2011-05-14 at 13:56 -0400, DJ Delorie wrote:
>>> I do not have a problem with the idea of single layer per physical
>>> layer,
>> PCB uses a single layer group per physical layer, with one or more
>> drawing layers within each group.  I see no reason to dump that now.
>> We just need to work on the UI and terminology so that it's less
>> confusing how it all works together.
> To counter that.. I see no compelling reason to keep it though.
> Certainly if we were to add the ability to tag objects and change
> viewing styles based upon tags.

It goes deeper than tags. It goes deeper than "UI and terminology", although the abuse of terminology is a symptom ("polygons" are not simple geometric figures, "elements" are not elementary, ...). The key thing that's missing is the idea that complex things are composed of simpler things. Circuits composed of subcircuits composed of footprints and nets, ...

Instead, there's a kludgy collection of magical objects. This is not only confusing to users, but it makes users unnecessarily dependent on the developers. Users should be able to define whatever composite objects they need, rather than be restricted to the limited built-in set. And the necessity to keep implementing magical objects from an open-ended list, and to insure that they all play nicely together, are unnecessary burdens on the developers.

> Given we'll probably end up keeping the irksome things, can we swap the
> terminology around?
> Physical PCB layer, mechanical drawing etc..
> --------------------------------------------
> WAS: "Layer group" ->  TO-BECOME: "Layer"
> Alternative terminology might be "foil" or "artwork", depending on
> context.

The material (copper, teflon, nichrome, ink, ...) that the elementary objects in a layer are made of is simply a property of the layer, I think.

> Logical group for partitioning geometry within a given PCB layer
> ----------------------------------------------------------------
> WAS: "Layer" -> TO-BECOME: "object group" | "sub-layer" | ....

Composite objects generally occupy multiple physical layers. So, shoehorning them into "layers" is confusing and unnatural.

John Doty              Noqsi Aerospace, Ltd.

This message contains technical discussion involving difficult issues. No personal disrespect or malice is intended. If you perceive such, your perception is simply wrong. I'm a busy person, and in my business "go along to get along" causes mission failures and sometimes kills people, so I tend to be a bit blunt.

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