kicad-developers team mailing list archive

[Ian McInerney <Ian.S.McInerney@xxxxxxxx>]

The question then becomes, how do we want to do this. Should we remove the
(scale ) s-expr from newly saved footprints and replace it with a units
one? Or do we make this a UI-only change and have the UI compute the
scaling factors that are saved in the file.

-Ian

On Tue, Sep 29, 2020 at 7:02 PM Seth Hillbrand <seth@xxxxxxxxxxxxx> wrote:

> I've never seen another package use VRML.  Everyone uses STEP.  I suspect
> if we were implementing this today, we would look at the tradeoff on
> support/benefit for VRML and limit ourselves to STEP as well.
>
> I like Ian's suggestion for unit options.
>
> -Seth
>
> On Tue, Sep 29, 2020 at 10:22 AM Jon Evans <jon@xxxxxxxxxxxxx> wrote:
>
>> Do other EDA tools allow model scaling?  Altium doesn't even allow VRML
>> import in the first place.
>>
>> On Tue, Sep 29, 2020 at 1:10 PM Seth Hillbrand <seth@xxxxxxxxxxxxx>
>> wrote:
>>
>>> Well, we've backed ourselves into a bit of a corner.  VRML is specified
>>> in meters, so if we're assuming inches, we're a bit off in left field.  But
>>> do we need three separate scale parameters?  We could reduce to 1, correct?
>>>
>>> In the official footprint library, we have 7 footprints that specify
>>> non-unity scaling. (Banana_Jack_[1-3], NS-Tech_Grove_1x04, Fuse_Blade_ATO,
>>> Fuse_Blad_Mini, Oscillator_SMD_TXC0_G158).
>>>
>>> -Seth
>>>
>>>
>>>
>>>
>>> On Tue, Sep 29, 2020 at 9:30 AM Ian McInerney <Ian.S.McInerney@xxxxxxxx>
>>> wrote:
>>>
>>>> We can't remove the scaling option until we make the VRML importer
>>>> handle proper unit selection. I have routinely run into the case where I go
>>>> OpenSCAD -> Wings3D -> KiCad and design a model using mm in OpenSCAD
>>>> because it makes for easier computations (all the datasheet values are
>>>> nicely given in mm) and then have to apply a scaling factor of 0.3937 to
>>>> all the axes in KiCad to make it the proper size because we seem to have a
>>>> hardcoded assumption about what unit system the VRML file is in.
>>>>
>>>> In fact, the KLC says: WRL files do not specify absolute dimensions.
>>>> KiCad normalizes model parameters to units of inches and the internal units
>>>> (dimensionless) of the WRL model must be scaled accordingly.
>>>>
>>>> -Ian
>>>>
>>>> On Tue, Sep 29, 2020 at 4:50 PM Seth Hillbrand <seth@xxxxxxxxxxxxx>
>>>> wrote:
>>>>
>>>>> There has been some discussion to removing the scale option here
>>>>> altogether.  The logic being that if you need the model scaled, you should
>>>>> be doing this in your solid CAD not in your electronic CAD.  I have come
>>>>> around to this idea and it might be worth implementing rather than doing
>>>>> the scale limiting.
>>>>>
>>>>> -Seth
>>>>>
>>>>> On Tue, Sep 29, 2020 at 4:52 AM Mário Luzeiro <mrluzeiro@xxxxx> wrote:
>>>>>
>>>>>> Hi all,
>>>>>>
>>>>>> I'm wondering if it is safe to limit the scale of shapes to be
>>>>>> positive values?
>>>>>>
>>>>>> Applying negative scales will cause inverted shapes and render issues
>>>>>> on the models.
>>>>>>
>>>>>> Could be that anyone in the world is using negative scale values?
>>>>>> or should be safe to limit it?
>>>>>>
>>>>>> This is related with this issues:
>>>>>> https://gitlab.com/kicad/code/kicad/-/issues/5817
>>>>>>
>>>>>> Mario
>>>>>> _______________________________________________
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>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> [image: KiCad Services Corporation Logo]
>>>>> Seth Hillbrand
>>>>> *Lead Developer*
>>>>> +1-530-302-5483‬ <+12126039372>
>>>>> Davis, CA
>>>>> www.kipro-pcb.com    info@xxxxxxxxxxxxx
>>>>> _______________________________________________
>>>>> Mailing list: https://launchpad.net/~kicad-developers
>>>>> Post to     : kicad-developers@xxxxxxxxxxxxxxxxxxx
>>>>> Unsubscribe : https://launchpad.net/~kicad-developers
>>>>> More help   : https://help.launchpad.net/ListHelp
>>>>>
>>>>
>>>
>>> --
>>> [image: KiCad Services Corporation Logo]
>>> Seth Hillbrand
>>> *Lead Developer*
>>> +1-530-302-5483‬ <+12126039372>
>>> Davis, CA
>>> www.kipro-pcb.com    info@xxxxxxxxxxxxx
>>> _______________________________________________
>>> Mailing list: https://launchpad.net/~kicad-developers
>>> Post to     : kicad-developers@xxxxxxxxxxxxxxxxxxx
>>> Unsubscribe : https://launchpad.net/~kicad-developers
>>> More help   : https://help.launchpad.net/ListHelp
>>>
>>
>
> --
> [image: KiCad Services Corporation Logo]
> Seth Hillbrand
> *Lead Developer*
> +1-530-302-5483‬ <+12126039372>
> Davis, CA
> www.kipro-pcb.com    info@xxxxxxxxxxxxx
>