DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s2048; d=yahoo.com;
	b=EqQ2MaSNte3rsexJe1+d17dPej/SaoZLCB8IxEaYw0FrhwxIzHU2nWuX82BKi8pAoZT3Q/NIgKHNyI+EO0bBrEtmTFoNlBU/gclnOk9jumpTWz45pwNmQqWt0300jB6uzyUc1W6sYOxH/6/ubdM8fnaKmj3GF/wephMb+CTiGjIaNHc/xzXpsUTYS2DGSGRaSbCmdSci3QORvAaaWIKa8GUyVkS5dRLsfOAW3YpmmhIKNfb/4VfbWwtJHasN1KWy/WPiCepSLp7ShP5bq2JQ1/V/qb3RHOGeSzt2c62gBdhnYOaePIEnRT6wOdkKi2C9Qn9SD0CQ5kZjpcWQf5WscA==;
Date: Thu, 20 Nov 2014 08:56:39 +0000 (UTC)
From: Cirilo Bernardo <cirilo_bernardo AT yahoo DOT com>
To: "geda-user AT delorie DOT com" <geda-user AT delorie DOT com>
Message-ID: <357043398.1941130.1416473799230.JavaMail.yahoo@jws10036.mail.ne1.yahoo.com>
In-Reply-To: <CALT8Ef6Aw-gd7hnySYBRazOBLhpMvMeBauyKiGiaundFNQSHog@mail.gmail.com>
References: <CALT8Ef6Aw-gd7hnySYBRazOBLhpMvMeBauyKiGiaundFNQSHog AT mail DOT gmail DOT com>
Subject: Re: [geda-user] PCB and 3D Views
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Reply-To: geda-user AT delorie DOT com
Errors-To: nobody AT delorie DOT com
Precedence: bulk

----- Original Message -----

> From: Shashank Chintalagiri <shashank DOT chintalagiri AT gmail DOT com>
> To: geda-user AT delorie DOT com
> Cc: 
> Sent: Thursday, November 20, 2014 2:05 PM
> Subject: Re: [geda-user] PCB and 3D Views
> 
> I had some free time last night and took a look at the export filters
> on LP699502. Here are some observations :
> 
> - My usual workflow for obtaining a 3D model of a PCB is :
>    (a) Export ps from pcb in multifile.
>    (b) Convert ps to dxf using "pstoedit -f dxf <fname>.top.ps 
> <fname>.dxf
>    (c) Import dxf into a sketch in solidworks
>    (d) Extrude PCB from a sketch overlapping the outline
>    (c) Cut out the necessary mounting holes and just enough pins to be
> able to assemble the mecahnically significant components (connectors,
> etc)
> 
[snip]
> - Given these observations, I think SCAD may not be the correct format
> to be attempting to do this in. The only real advantage I see with
> SCAD is interoperability with the limited SCAD environment. From the
> technical perspective, having a full mesh _may_ make vibration and/or
> thermal simulations nicer, but that's going to need a whole lot of
> work to model the solder joints and so forth. IDF may indeed be a
> better bet, with IDF-SCAD conversions scripted outside of PCB. We're
> not talking about real-time 3D renders within PCB anyway - which is
> what openSCAD and similar native 3D formats would afford us. Since
> we're only really taking component placement information from PCB and
> providing everything else externally, it's probably easier (and
> cleaner) to formalize that relationship in IDF.
> 
[snip]


I would agree with you about IDF; it is an ancient but still commonly
used interchange format and supported by most MCADs at some level.
In SolidWorks you need the CircuitWorks package to import IDF but
if you have the programming tools you can always create your own
IDF->SW importer and avoid paying extra for CircuitWorks; I can't
speak for the availability of the IDF importer in other MCAD
packages. The IDF format specification is also freely available
and with the IDF support code from KiCad all you have to do is provide
the translation layer between PCB and the IDF framework. In principle
the framework also allows an IDF importer to be easily implemented,
but in practice I haven't used that feature since no one seems to
be asking for it. I wrote the IDF code and the IDF to VRML conversion
tool, so if you want to make use of the code and need to make any
changes in the licensing for whatever reason you can always ask me.

One more note on IDF: FreeCAD has an IDF importer. It is very basic
and a much better (strict compliance, more error checking etc) one
can probably be implemented using the IDF framework from KiCad,
but it does the job and can be used to convert an IDF board into
a STEP model for use in other MCAD software if the MCAD does not
already support IDF imports. I wouldn't convert anything more than
the board though since OpenCascade cannot produce a hierachical
assembly model and will create a STEP model with hundreds if not
thousands of 'parts' which software like SolidWorks will convert
into hundreds or thousands of files on disk.

STEP AP203, AP214, or AP203 2nd edition would be the ideal output
format since all MCADs will have native importers at no extra
charge, however it is an enormous job to implement any of those
formats; I am slowly working out STEP for KiCad but progress is
imperceptibly slow.

- Cirilo