X-Authentication-Warning: delorie.com: mail set sender to geda-user-bounces using -f X-Recipient: geda-user AT delorie DOT com X-Original-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:content-transfer-encoding; bh=d7se1PMtIod/GZlgOX9l5cegvLK6eNvtmgxxWJ/nGfY=; b=enkm4qdWgVd5OxFjv8/Vdq/ayxJ+IN0sMqE01qIkFIlLtI3Hx9U2A9PyK4ksgd6gQw IBBX9oiOfumsyfdwg1X3AkrGk2Q+aHQGzlZgezINmc7xq4HWC3OgOv/pcgYNFO4ohH2P qN973F9WWgYJywft8gWu8kQuGxPEc6pPA86LVgzoteiZQkxXoeNms7JTFHKzL6va9WJR jcIZquzMm6gbZXUwpeiZMygwRlkOLJaZdO92aPz/Wntn/xdldDCxlfVO76Zx5I1nzjGO JqYVNDVI0UvABbvmASQqjY2YyvtiBcmNuJZzbOfRRu7Czi0dsxPzIKiOejbigEousqv2 KrmQ== MIME-Version: 1.0 X-Received: by 10.202.85.146 with SMTP id j140mr5542661oib.4.1450791015222; Tue, 22 Dec 2015 05:30:15 -0800 (PST) In-Reply-To: <20151222140345.07f48e9256784e9bf0718efa@gmail.com> References: <20151222140345 DOT 07f48e9256784e9bf0718efa AT gmail DOT com> Date: Tue, 22 Dec 2015 13:30:15 +0000 Message-ID: Subject: Re: [geda-user] Cross project collaboration on data models From: "Peter Clifton (petercjclifton AT googlemail DOT com) [via geda-user AT delorie DOT com]" To: gEDA User Mailing List Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by delorie.com id tBMDUKfb015950 Reply-To: geda-user AT delorie DOT com Errors-To: nobody AT delorie DOT com X-Mailing-List: geda-user AT delorie DOT com X-Unsubscribes-To: listserv AT delorie DOT com Precedence: bulk Hi Nicklas, What you appreciate about gEDA is one of its fundamental early design choices (way back before my involvement in the project), and one of the strongest aspects which makes gEDA what it is. I am not trying to change this - and it would be an aspect of any cross-tool open EDA data-model we would have to ensure was represented in order to fit gEDA's needs. I'm perhaps focusing a more on the PCB side (where our existing data-models and file format most often causes problems), PCB often bumps into limitations with its file-format not expressing certain design aspects / concepts, and often needs to be extended in an ad-hoc way. One key aspect I need to get in at some point - is that of a mechanical outline.. which is one of the key missing pieces holding back my 3D board export code from moving upstream. (My test-code takes a guess based on some heuristics, after looking at the outline layer, but this non-semantic data is a "bad idea", and not one I'm prepared to push upstream). One distinction to draw, is that data-model and file-format are two distinct topics. They are very much related, but - for example, one could have multiple file format which all represented information according to a common model. In the case of my mechanical outline, this is very easily modelled by the software (as a polygon representing the board shape), but no file-format to load/save it exists yet. A more complete treatment of board shape might require a more complex models.. take for example a flex circuit - where the board can have different shapes per layer. There are a lot of situations to handle correctly - and ideally, in a forward compatible way (or get it right first time!). To take another PCB example - lets say pad-stacks. Some CAD systems define these explicitly, and reference those from the board design, footprints etc.. gEDA/PCB does not, it stores (rather limited) information about pad geometry in-situ, for each pad instance, for each component instance in the design. Our data-model has no concept of a referenced pad-stack, which means it is not convenient to make mass changes to all instances of a particular type of pin/pad/... on the board. (Software would need to pattern-match / guess which pads are supposed to be the same - no semantic information exists). Peter On 22 December 2015 at 13:03, Nicklas Karlsson (nicklas DOT karlsson17 AT gmail DOT com) [via geda-user AT delorie DOT com] wrote: >> I think this is of critical importance to allowing a (currently) smaller >> player like gEDA to survive amongst more successful / active projects. > > Only reason I used gEDA is because of thin bindings which allow to start with a simple sketch without all details and fill in more information then needed. Start of a new circuit is usually a simple sketch or block diagram altough some components only have one order number others like capacitors,resistor have diferrent values,sizes and order number may be the last step or may even change after board have been delivered. > > If it is possible to use fileformat from other software I however think it is a good idea. To copy some other software I think is rather pointless because in such I would be better of start using it directly.