[Solved] PCB with inner shape: very cumbersome to design!

I have to make a PCB with thi inners shape because it has to be inside this box.
So it’s a square but inside there must be a hole that has this protusion.
I found very cumbersome if not impossible, to design it in PCBNew

is there a way to by-pass the enormous graphical limitations of PCBNew so that I can design this shape and finish this PCB?

Found a way:

Exporting the DXF of the box layout, properly scaled, then in PCBNew
File > Import Graphics (Ctrl+Shift+F) and importing the PCB as here:


it seems working. Or better: I was constrained to redosing everything in Kicad using the DXF as guide, because otherwise the PCB was considered bad formed. But at least I got the anchor points.

Please Devs, do something with PCBNews or special PCBS are impossible.


If you have a properly formed DXF file then you should be able to directly import it in the PCB Editor on the Edge.Cuts layer. But there are lots of reasons why mechanical cad programs do not always generate proper DXF file output. Sometimes they have “double lines”, and also endpoints not matching with each other is relatively common. .DXF uses a floating point format, which has inherent rounding errors, while KiCad uses (flawless) integers in nanometer resolution, which preserves quite small errors from the DXF input.


This is indeed very difficult directly in KiCad especially because arc editing is very limited.

The easiest way to do this inside KiCad would probably be to create the protrusion first which is easy if you do it vertically. Then create an arc and edit its start and end properties manually according to the protrusion’s bottom coordinates, calculate the angle with some trigonometric function and edit the angle property. Finally select and rotate the whole thing.

Indeed, a 2D CAD application is recommended for this task. I would try this kind of thing with FreeCAD sketch which can be exported to KiCad with StepUp workbench.

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When trying to do anything more complicated with arcs in KiCad I typically know the center and radius but not the arc ends. Editing mode when you have center and radius defined and you modify only an arc end is active only when adding the arc for the first time. So I end with deleting and adding an arc several times.
I have written a feature request to allow for this way of arc edition also later when arc is already added.
Here it is:


Hi Paul

Yes I did it. I exported in DXF via Fusion 360. Although I got issues and malformed PCB when I tried to get the project finished.
Of course I found a workaround and I happily finished it, although it would be better to have a more efficient native tool.

KiCads own tools are mostly adequate for drawing simple PCB outlines (although especially the arc tool needs some updates). But apart from that, a full mechanical CAD program is a quite complex piece of software, and a lot of people have their own preferences on which tools to use for mechanical CAD. Therefore, KiCad, just like any other PCB design program mostly relies on import from other tools for more complicated PCB outlines.

But I am curious what the exact problems where. Was there something wrong (with coordinates?) of the DXF export?. I can imagine KiCad could use some extra rounding here because of the use of floats in the DXF format.

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Agreed. The critical tools missing are:

  • Trim (delete segments by intersection). Alternatively split
  • A rotate tool

DXF is just a very problematic format to begin with, nearly every time i deal with dxf there’s something that went wrong. There are just so many dialects of it.

But in fact this one is easy to draw in KiCad too.

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i have not clue what was the problem.
I just exported the DXF form Fusion 360 and imported in KiCAD
And when I went on View > 3D, i got the malformed PCB warning.

Then, being not able to figure out where it was the issue and however: how to repair it (since the strong limitations of the KiCAD’s tools), I tried to use the DXF as template, adn to redraw each line and arc, anchrating it to the DXF primitives. Then I removed the DXF. It worked.

I agree with @joojala about instruments missing tools. I mean we don’t ask for fancy stuff. But just a decent minimum that enable us to work in 2023 with current needs.

Indeed the trim tool, the rotate tool, etc …small stuff but really comfortable to have.

About FRs

I don’t send any FR any longer since several requests are there for years and forgotten. So it’s needless to be there each time to ask the same things.

However even if “accepted” they will be available perhaps in 2025 … or 2026 so a no-go procedure (see the resize of an imported SVG (to place logos etc … but this is not the topic).

Only ok, I see that DXFs have some kind of limitations/problems as well and we (all) need to find workaround with them … for a certain extent it’s possible.

the goal in my project is to have a PCB that perfectly fits the box that should contain it, and it has a particular and strange environment where to work and how to work.

I’m thinking also to all the other ones that have similar issues and they didn’t find a way.
Ok try with DXFs. It’s not a straight way but it works (for now)

Now I’m curious…

ok … Unfortunately KiCAD doesn’t export the F3D files of Fusion 360 Personal Edition, so all the pads, routes etc are not visible.
However I tested the dimensions: it worked out

You can use FreeCAD and the KSU-StepUp workbench to Load the PCB, PADs, Traces then, export as STEP/other then, load it into Fusion…


Do not take it personal please, however I do refuse to install FreeCAD again on my machine. I definitely closed with that stuff.

i wil use it ONLY if Fusion and Solid Edge will have their personal/community license deleted. Then I will have not any other choice; but till that time: please don’t even name it with me.

As I said: please don’t take my reaction as personal. Nothing against you and your help.

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I wanted to install it again to see ife ever I DON’T get any issue … and indeed here the issue.the workbench is correctly installed

The settings in Preferences that the Workbench wants, are done.
The result is identical to the one I get in Fusion.



The preferences of FreeCAD


The suggested one by the Workbench

Uninstall it again. At the end, it was just to have a fully vision of the finished product. In 2023 again not possible (it looks like the late 9às :smiley: ). … ok it wil be for the next millennia then :smiley: everything is possible … just leave the time goes by …

You missed to read the manual :wink:

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I suppose I could go through my settings but will post only the following and assume you’ll take care of other settings…

Screen Shot 2023-10-14 at 13.14.58

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Yep that worked out.
thanks a lot.

But I get at each export this … classical FreeCAD stuff … it’s not a workbench issue. I got several (zillions) times this not responding even during a normal sketch, for no reason and random.


When FreeCAD say’s ‘Not Responding’, I wait a minute until it finishes then it continues (hopefully).

Do a small test with PCB having one or two Pads and tracks. See what happens…

After 6 frozen I was able to export .STEP

The final resul tis what you told indeed. But I had to sweet a lot to get it done.
I hope one day KiCAD will export directly on that way without the need to go to FreeCAD.

While I was swearing for the FreeCAD’s pseudo-functioning, I tried also with Blender (that I use for video productions) … but it’s not a great stuff neither with STLs (STEPS are no yet a format that it manages). Ok, however Blender it’s for other purposes and in it’s field of application is brilliant. But for these things, not (yet).

So I had jso hope FreeCAD was stopping to behave as it used ot. And finally I got it done.

Believe me it’s not a complex PCB at all, but I Iike to have the final vision of the object I’m designing.

FYI, copper export to STEP is supported in nightly KiCad builds.

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