X-Authentication-Warning: delorie.com: mail set sender to geda-user-bounces using -f X-Recipient: geda-user AT delorie DOT com X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.98.4 at av01.lsn.net Message-ID: <53C5DDD4.404@ecosensory.com> Date: Tue, 15 Jul 2014 21:05:08 -0500 From: John Griessen User-Agent: Mozilla/5.0 (X11; Linux i686; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: geda-user AT delorie DOT com Subject: Re: [geda-user] Re: Layers and footprints References: In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Reply-To: geda-user AT delorie DOT com On 07/09/2014 07:50 AM, Peter Clifton wrote: > I'd be tempted to make pads layer objects going forward, (and let them reside on any copper layer), but perhaps for now, keeping > them "special" and outside the normal layer data structure may be cleaner due to the fact they place objects on multiple > "layers". (Copper, mask, paste etc...) There's not much limit in computing language or data structures today, so it will give the best return on time spent to model physical reality well, rather than use "special" layers, special cases, etc, that must logically combine to match reality. In other words, have pads be defined per physical layer and affect things that are 3D physically near them and nothing else. Making things self consistent like an e field is ultimately simpler than a giant text sort kinda giving the right answer. And you can use assertions on the local volume of material to keep errors in check. Otherwise, you can have "action at a distance" spaghetti code effects. Of course a physical material and 3D space model means a lot of PCB and gschem redesign, but... why waste any life hours of any developers on dead ends? Incremental change is the only way we've seen work in FOSS, so any move towards such goals that can be incremental is what to "wrack your brain" for... On 07/09/2014 07:58 AM, Peter Clifton wrote:> I've personally never had a board vendor want changes in gerber data to accommodate manufacturing processes. This is generally > something they can do themselves using their CAM software if they need. But, that drops the responsibility of repeatable successful fabbings on the fabber, when one should keep it him/herself, or maybe have a lot of waste and loss.