Error: Board has malformed outline (self-intersecting)

[Falstaff]

Hello everyone

I’ve been working on a pcb with round outlines by importing a .dxf file from FreeCAD, and I encountered a large amount of following errors:

• Error: Board has malformed outline (self-intersecting)
• Error: Board has malformed outline (segment has null or very small length: 1 nm)

I cannot select individual segments.
I can’t find any gaps or open shapes.

Should I simply change the severity (or even ignore these errors completely)?
I am rather new to this, constructive input would be appreciated.

Specifications
KiCAD
Application: KiCad PCB Editor x64 on x64

Version: 9.0.0, release build

Libraries:
wxWidgets 3.2.6
FreeType 2.13.3
HarfBuzz 10.2.0
FontConfig 2.15.0
libcurl/8.11.1-DEV Schannel zlib/1.3.1

Platform: Windows 11 (build 26100), 64-bit edition, 64 bit, Little endian, wxMSW
OpenGL: Intel, Intel(R) UHD Graphics 620, 4.6.0 - Build 27.20.100.8854

Build Info:
Date: Feb 19 2025 17:46:53
wxWidgets: 3.2.6 (wchar_t,wx containers)
Boost: 1.86.0
OCC: 7.8.1
Curl: 8.11.1-DEV
ngspice: 44
Compiler: Visual C++ 1942 without C++ ABI
KICAD_IPC_API=ON

FreeCAD
OS: Windows 11 build 26100
Architecture: x86_64
Version: 1.0.0.39109 (Git) Conda
Build type: Release
Branch: (HEAD detached at 1.0.0)
Hash: 2fcc5317fe3aee96ca73475986a577719fc78e20
Python 3.11.10, Qt 5.15.15, Coin 4.0.3, Vtk 9.3.0, OCC 7.8.1

Stylesheet/Theme/QtStyle: FreeCAD Light.qss/FreeCAD Light/Fusion

[gschelotto]

In v8 Tools-Repair Board option try to repair board outline but I’m not sure if it present in v9 (I’m not using this version right now)

[der.ule]

Couple of issues that have come up in the past:
+The DXF has some superimposed lines
+Arcs are not exactly connecting the lines end
+The DXF was not imported on to the Edge.Cuts layer

If none of this point help you, are you able to share the DXF here for forum members to take a look?

If possible try to upgrade to v9.0.2 as there are many bugfixes since the beginning of the year.

[paulvdh]

Also:

@Falstaff

Version: 9.0.0, release build

Do not keep using such an old KiCad version. V9.0.2 is the current version, and there are have been lot of bug fixes in the last few months. Especially the first few versions of a mayor KiCad version have relative many bugs.

[maui]

you may consider kicadSteUp FreeCAD workbench

[mf_ibfeew]

Should I simply change the severity

NO. this is a really important DRC check, the board outline must be correct otherwise the gerber export can (and likely will) not correctly represent your board.

[BlackCoffee]

FreeCAD has several important ‘DXF Export’ settings to make the DXF play well with Kicad, regardles of Kicad version and FreeCAD version.

ADDED: Video… And, sometimes the DXF looks good but has a misplaced point/mated line(s). Click the Arrow and checkout the Mating of the lines… and move one and re-join it…

[RaptorUK]

@Falstaff

I cannot select individual segments.
I can’t find any gaps or open shapes.

Yes you can, you will need to break the group and then you may well find you have multiple lines overlapping . . .

For example, this thread has the same/similar issue:

Board Outline becomes malformed without touching it

You have duplicate lines . . . [image] . . . probably as a result of a DXF import ? I’ve had it before.

[BlackCoffee]

Kicad and FreeCAD have settings to deal with DXF import/Export. If they are not set ‘correctly’, trouble happens.

Below is a comparison of Kicad (Version 7) DXF Plot(Export) and Importing the Exported DXF.

Discover the FreeCAD settings on your own…