kicad-developers team mailing list archive

[Mário Luzeiro <mrluzeiro@xxxxx>]

From my user experience: I use the 3 scale values on my projects.
I created unit solids (eg: 1mm cube, 1mm cylinder radius / thickness, etc) and then I use it to quickly create shapes (by adjusting X,Y,Z scale) to populate the board if I don't have the proper STEP model.
This is helpful to create round buttons, push buttons switch house packages, displays (attached is an example I made just using 1mm cubes)
I'm using WRL but I believe it should work if I had used STEP scaled and then export it for CAD purposes.

If you remove scale at all, I will need to learn and use a new CAD software :/ :)

My suggestion is keep the scale but hide (or disable) it by default on the UI and it should only be enabled by clicking on some checkbox, at that time, displaying some message to the user "this is not a good idea for CAD.."


> I'm not sure the history of why VRML was chosen as the first model type that was supported

Maybe at that time it was created was a very time consuming thing to implement.
For STEP we need a 3rd part library (as it is very complex format).
On the current 3D-Viewer implementation, Cirilo worked alone on the model importer code alone and it took some months of work..

Mario

________________________________________
From: Kicad-developers <kicad-developers-bounces+mrluzeiro=ua.pt@xxxxxxxxxxxxxxxxxxx> on behalf of Seth Hillbrand <seth@xxxxxxxxxxxxx>
Sent: 29 September 2020 19:01
To: Jon Evans
Cc: kicad-developers@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Kicad-developers] 3D-Viewer: limit scale to positive values?

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<mailto: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<mailto: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<mailto: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<mailto: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<mailto: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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[KiCad Services Corporation Logo]
Seth Hillbrand
Lead Developer
+1-530-302-5483‬<tel:+12126039372>
Davis, CA
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[KiCad Services Corporation Logo]
Seth Hillbrand
Lead Developer
+1-530-302-5483‬<tel:+12126039372>
Davis, CA
www.kipro-pcb.com<https://www.kipro-pcb.com/>    info@xxxxxxxxxxxxx<mailto:info@xxxxxxxxxxxxx>

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