kicad-developers team mailing list archive

[Cirilo Bernardo <cirilo.bernardo@xxxxxxxxx>]

Hi Brian,

 I suggest we leave the scaling etc until after the stable release; it's a
nightmare.

 Historically the scaling allowed users to reuse similar models if they
didn't already
have a suitable model, for example grow or shrink a THT 0.25W resistor to
pretend
it's a 0.5/1.0/2.0W type or a small glass-encapsulated diode. I think with
the
currently available tools and numerous models there is no need to support
this
intended behavior and the GUI should only have a Z rotation and a Z offset;
to
remove all ambiguity we do need to specify the units of the Z offset.

 Now different sources for models will still have different reference
points, scales,
etc. I propose to handle these by having an orientation file which sits
alongside
the model file - let's call it a ".cod" (component orientation data) file.
The cod file
gives the required scaling, 3D rotation, and offset required to put the
component
into a reference orientation suitable for KiCad; different footprints
should then only
require a different Z rotation and the Z offset should only be necessary
when
positioning multiple parts (ZIF socket + IC). The cod file should also save
users
the hassle of working out the magic required to obtain a sensible
orientation and
scale for a foreign model each time they use it. Even more importantly, the
same
scheme can be used to handle other 3D models as well, especially IGES in the
near future. The down side of using a cod file: current 3D code needs to be
modified to make use of it; this is not necessarily an easy task given the
VRML
scaling assumptions in the code.

Now as for FreeCAD, these Python scripts were just brought to my attention:
http://sourceforge.net/projects/eaglepcb2freecad/

I haven't tried them out myself yet, but you can see it's a popular
download.
Don't let the name fool you: it's meant to handle Eagle, KiCad v3 and v4
pcbs, IDFv2/3/4, and even IGES assemblies.

As far as FreeCAD goes, personally I find it extremely difficult to work
with
so I'll continue to use SolidWorks. More recently the SolidWorks team
seems to have left Dassault to start their own online project: OnShape.
AutoCAD offer a similar service and no doubt others will follow. So feel
free to try the likes of OnShape and tell them how to improve their product.

- Cirilo


On Mon, Jun 1, 2015 at 6:11 AM, Brian Sidebotham <brian.sidebotham@xxxxxxxxx
> wrote:

> Hey guys,
>
> I only just got round to using 3D with KiCad. Mainly because I
> normally use Solid Edge for 3D solid modelling, and I could never be
> bothered to use FreeCAD at home because, well, it's not Solid Edge!
> Anyway, I just compiled FreeCAD on my Mint box and I have to say it
> works really well these days - so I should put it to use.
>
> I designed my part in metric in FreeCAD, exported to WRL and used that
> in KiCad (All works well there, so thanks to everyone who's been
> working on that part of KiCad, it now "just works"). The problem I had
> was one of scale. To get the scale right, the scale needs to be input
> as 0.393701 (1/2.54).
>
> The units in the WRL are in mm. Can I put some buttons in to set the
> scale? Buttons like "mm, cm, inches, and feet" which would be useful
> to me. Is this something can happen pre-stable release?
>
> It seems like a usability thing to me. Not many people are going to
> guess at 1/2.54.
>
> There's very minimal impact on the manuals. Perhaps more people are
> using FreeCAD compared to Wings3D these days anyway?
>
> All thoughts or other ideas are welcome! :D
>
> Best Regards,
>
> Brian.
>
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