[Solved] PCB Exporting .STEP: Scaled models detected and no export of that model

Layout 3D Models
#1

In one PCB Project, I have a couple of components 3D modeled using FreeCAD.

WHAT’S I NOTICED
I already noticed that when I design the footprint, it respect the measures,
When I design the 3D Model in FreeCAD, it’s exported correctly (I already 3D printed several things), but when imported into KiCAD, I don’t know why, I have always to scale it for some reason.
But if all it’s made 1:1, why should I scale it again and not just repositioning it?
No idea

WHAT’S OCCURRING WHEN EXPORTING
When I export the PCB as .STEP (as .WRL: no problem), appears this window:
image

as result, into the .STEP file, there are all the KiCAD native components, but NOT mine ones
Which is irritating, because it’s nor written: it will be not exported. But it tels: Model scaling is not reliable.
ok it decides do not export them for some practical reason: I do accept BUT why doen’t it export them?
Yes they are scaled, but because something occurs when imported (as I said above)

HENCE
WHY when I import a component that’s correctly sized in CAD, exported in .STEP and imported into KiCAD should be always 1.8-2 times bigger than what should it be?
is there a way to impede this and to be able to avoid all these issues at once?

Can you help me on this please?

#2

You did not post enough info to be able to diagnose the problem but, I suggest you consider:
• FreeCad setting is for mm (Pref’s>General>Units
• Also, ensure your STEP export is for mm (Import-Export>Step…
ADDED: Also try checking ‘Legacy’ in the Step Export panel

Screen Shot 2023-01-21 at 14.28.56
Screen Shot 2023-01-21 at 14.28.561648×386 54.3 KB

• Some poorly designed models will successfully export from FreeCad but, the Step may have problems (somewhat like a bad .STL that needs repair/healing but also exports successfully)
• Did you export from StepUp or from PartDesign or Part workbench?
• Did you export a Step of a Compound of the model or of the Last Item in the Tree or the full Tree?
• What happens when exporting a simple object?

If not solved after looking into the above, Post the FreeCAD file, I’ll look at it

#3

Those two files are WRL, which is a type intended for appearance rather than mechanical accuracy. It used to be common for them to be scaled by 1:2.54 thanks to the use of 0.1" units

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#4

Yes FreeCAD is already setup in mm. I don’t use Inches, since I’m in EU
i exported form PartDesign, at that time it was the only WB I was able to use (I created the parts a couple of years ago)
I exported the Last Item, since I didn’t know how to use any other WB. However the part is very easy, being a double inductor contained into a rectangle extruded and 4 pins (4 cylinders). That’s it

I will try to get the part again and to re-export checking the first point you highlighted especially the “legacy” since i didn’t pay attention on this, having, at that time, not confidence at all with FreeCAD

#5

@BlackCoffee @davidsrsb thank you guys. Following your indications, I was able to export it correctly

I checked the old project in FreeCAD. I’ve remade the parts, and exported it properly.
Re-imported on KiCAD just repositioned, and exported the PCB: fantastic. now it is as it should be.

Thank you so much

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