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Date: Mon, 13 Jul 2015 13:11:54 +0200 (CEST)
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From: gedau AT igor2 DOT repo DOT hu
Subject: Re: [geda-user] PCB interface (ECAD vs. MCAD)
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On Mon, 13 Jul 2015, Chris Smith (space DOT dandy AT icloud DOT com) [via geda-user AT delorie DOT com] wrote:

>
>> On 13 Jul 2015, at 10:33, gedau AT igor2 DOT repo DOT hu wrote:
>
>> I think it's PCB is a bit more than 2d - or rather, should be. Ideally, it knows the thickness of layers and which of the layers are connected by a plated drill. This how blind or burried vias would be possible.
>
> Why does it need to know the layer thickness?  It?s a useful property to associate with the layer, but I don?t see why PCB needs to know about it.

If it knew thickness, it could do more calculations. Beyond a certain 
complexity, it could help if your cad can help you drawing impedance 
controlled lines without you having to calculate things first.

PCB doesn't support these things now, but if you are thinking about a 
largeish transition, it's better to consider these too.


>
>> Btw, I see the validity in your MCAD->ECAD idea; actually when I need to do draw something mechanical, if it's small, I sometimes just use PCB. I shoulnd't, but I'm so much faster with PCB than with librecad for those very small things... A typical example is small floorplans, especially if I don't need dimension lines (they are expensive in PCB and cheap in librecad). My scale is usually 1mm PCB = 1m real life.
>
> I guess I?m kind of the opposite.  I?m not a power PCB user: the stuff I work on is rarely more than two layers and never larger than Eurocard sized.  However it nearly always has some kind of panel mounting.  When I start a layout, I nearly always want to start with the mechanical components, to say: distribute these switches/LEDS between here and here, on 20mm centres.  This is trivial with 2D MCAD, but cumbersome with PCB.

I agree PCB lacks some of the common and useful features of 2d mech cads. 
I plan to address this in the long run in pcb-rnd, because I often need 
these features too.

Regards,

Igor2