Re: gEDA-user: General Layers questions

[John Doty <jpd@xxxxxxxxx>]

On Mar 19, 2011, at 11:01 AM, Martin Kupec wrote:

> On Sat, Mar 19, 2011 at 10:56:27AM -0600, John Doty wrote:
>> 
>> On Mar 19, 2011, at 10:50 AM, Martin Kupec wrote:
>> 
>>> On Sat, Mar 19, 2011 at 10:14:54AM -0600, John Doty wrote:
>>>> 
>>>> On Mar 18, 2011, at 2:23 PM, Martin Kupec wrote:
>>>> 
>>>>> If layers types would be defined by attributes, someone would be able to
>>>>> declare one layer both as conductive and as silk for example. That could
>>>>> cause me a nighmares. That is why I insist on 'typed' layers, not
>>>>> 'tagged' layer.
>>>> 
>>>> No. The nightmare is classification.
>>>> 
>>>> It's perfectly possible to put conductive ink on a board with a silkscreen process.
>>> No problem here. Just define that conductive ink as copper or conductive
>>> type layer. I don't care how that layer happens to be manufactured.
>> 
>> No. For describing geometry, I agree that the manufacturing process is irrelevant. But the layer needs properties, not some arbitrary classification.
> 
> I never said that you cannot add additional properties(attributes) to
> the layers. I am just saying that there should be some, as you say,
> arbitrary classification. And than you refine that clasification by some
> properties. But the basic classification will be clean and understood by
> all parts of pcb. The additional properties can be admited just by some
> parts.

That's a design approach that leads to metastatic problems down the road. You should avoid the sloppy mental tendency of humans to classify where nature is continuous.

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




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