Unclear error message when invalid sketch used in AddFoldWall (v1.0.1)

[HOC-Vo]

Describe your issue

Hello, I have a problem with version 1.0.1.

Last week, I designed a sheet metal part in Sheet Metal using version 1.0.0.
Today, I installed version 1.0.1 and can no longer edit the BaseShape in Sheet Metal.

The properties window no longer appears when I double-click, and a message appears in the output window.

The icon next to BaseShape also looks like a normal blue cube.

For a small project, Sheet Metal works satisfactorily as usual.

I have already installed version 1.0.1 and also Sheet Metal a second time - unfortunately, without success :?:

Cu60_Verbinder.FCStd is correct
Cu60_NH_L.FCStd is defect in version 1.0.1

FreeCAD version info + SheetMetal WB version

OS: Windows 10 build 19045
Architecture: x86_64
Version: 1.0.1.39285 (Git) Conda
Build type: Release
Branch: (HEAD detached at 1.0.1)
Hash: 878f0b8c9c72c6f215833a99f2762bc3a3cf2abd
Python 3.11.12, Qt 5.15.15, Coin 4.0.3, Vtk 9.3.0, OCC 7.8.1
Locale: German/Germany (de_DE)
Stylesheet/Theme/QtStyle: OpenLight.qss/OpenLight/Fusion
Installed mods: 
  * OpenTheme 2025.5.20
  * sheetmetal 0.7.24

Put here any screenshots or videos (optional)

![Image](https://github.com/user-attachments/assets/5abd0ec5-b852-47b6-8888-e3a0ff49

FreeCAD.zip

95f0)

[mpilato-fpsas]

I can confirm, the AddFoldWall operation does not work on parts designed on Freecad v1.0.1
It just gives a the following error in the "report" panel :

10:43:56  pyException: Traceback (most recent call last):
  File "/home/mathieu/.var/app/org.freecad.FreeCAD/data/FreeCAD/Mod/sheetmetal/./SheetMetalFoldCmd.py", line 276, in execute
    s = smFold(
        ^^^^^^^
  File "/home/mathieu/.var/app/org.freecad.FreeCAD/data/FreeCAD/Mod/sheetmetal/./SheetMetalFoldCmd.py", line 107, in smFold
    CutSolids = FoldShape.cut(toolExtr)
                ^^^^^^^^^^^^^^^^^^^^^^^
<class 'ValueError'>: {'sclassname': 'N4Part18NullShapeExceptionE', 'sErrMsg': 'Null shape', 'sfile': '/run/build/FreeCAD/src/Mod/Part/App/TopoShapeExpansion.cpp', 'iline': 1395, 'sfunction': 'Part::TopoShape& Part::TopoShape::makeShapeWithElementMap(const TopoDS_Shape&, const Mapper&, const std::vector<Part::TopoShape>&, const char*)', 'swhat': 'Null shape', 'btranslatable': False, 'breported': False}
10:43:56  Fold: {'sclassname': 'N4Part18NullShapeExceptionE', 'sErrMsg': 'Null shape', 'sfile': '/run/build/FreeCAD/src/Mod/Part/App/TopoShapeExpansion.cpp', 'iline': 1395, 'sfunction': 'Part::TopoShape& Part::TopoShape::makeShapeWithElementMap(const TopoDS_Shape&, const Mapper&, const std::vector<Part::TopoShape>&, const char*)', 'swhat': 'Null shape', 'btranslatable': False, 'breported': False}

Even opening this part in Freecad v1.0.0 does not allow me to fold it.

But, if I create a part using Freecad v1.0.0, I can then fold it alright using both Freecad v1.0.0 Freecad v1.0.1 !

See attached project (created with Freecad v1.0.1)

All attempts made using latest version 0.7.24 of the sheetmetal addon.

Freeacad_Sheet_Bug_V101.FCStd.zip

[Syres916]

@shaise I'll have a go at Bisecting the releases/FreeCAD-1-0 branch to see what could possibly have been backported to break this but I would have thought it would not work using 1.1dev also, really strange. As I'll be stopping and starting the Bisect between digging up my garden it could be 24 hours before I have an answer.

[Syres916]

@mpilato-fpsas please, please put your full info on reports, I'm assuming you have FreeCAD set to Francais?

@shaise I think I've already narrowed down why we haven't had many more reports on this, it looks to be a non-English language issue so I'll have to do all my tests between Bisect steps in French!!

[shaise]

@HOC-Vo , Cu60_NH_L.FCStd does not work on 1.0.0 as well, it looks like corrupted file.

@mpilato-fpsas , Your example does not work both on 1.0.1 AND 1.0.0. To work with fold-a-wall you need to extend the sketch line beyond the edges of the face.

see attached:

Freeacad_Sheet_Bug_V101_correct.zip

[pilatomic]

mpilato-fpsas here, but on my personal account.

I apologize for the incomplete report, I did not have much time to create the report from my workplace.
I have reproduced the issue at home, on a setup similar to the one I have at work :

Freecad Version info :

OS: KDE Flatpak runtime (X-Cinnamon/cinnamon/xcb)
Architecture: x86_64
Version: 1.0.1.39285 (Git) Flatpak
Build type: Release
Branch: (HEAD detached at 878f0b8)
Hash: 878f0b8c9c72c6f215833a99f2762bc3a3cf2abd
Python 3.12.10, Qt 6.9.0, Coin 4.0.3, Vtk 9.3.1, OCC 7.8.1
Locale: French/France (fr_FR)
Stylesheet/Theme/QtStyle: unset/unset/fusion
Installed mods: 
  * sheetmetal 0.7.24

Simple project that shows the issue, with the sketch line extended beyond the part to be folded :
Freecad_Sheet_Fold_Issue.FCStd.zip

And the same exception :

20:45:09  pyException: Traceback (most recent call last):
  File "/home/pila/.var/app/org.freecad.FreeCAD/data/FreeCAD/Mod/sheetmetal/./SheetMetalFoldCmd.py", line 276, in execute
    s = smFold(
        ^^^^^^^
  File "/home/pila/.var/app/org.freecad.FreeCAD/data/FreeCAD/Mod/sheetmetal/./SheetMetalFoldCmd.py", line 107, in smFold
    CutSolids = FoldShape.cut(toolExtr)
                ^^^^^^^^^^^^^^^^^^^^^^^
<class 'ValueError'>: {'sclassname': 'N4Part18NullShapeExceptionE', 'sErrMsg': 'Null shape', 'sfile': '/run/build/FreeCAD/src/Mod/Part/App/TopoShapeExpansion.cpp', 'iline': 1395, 'sfunction': 'Part::TopoShape& Part::TopoShape::makeShapeWithElementMap(const TopoDS_Shape&, const Mapper&, const std::vector<Part::TopoShape>&, const char*)', 'swhat': 'Null shape', 'btranslatable': False, 'breported': False}

I cannot exclude a case of user error from me, as I'm quite new to this workbench, but I just can't see where I could be going wrong.

EDIT : Due to the way I constructed my sketch, I have a point in the middle of the fold segment. If I remove the point in the middle of my folding segment, it folds alright, so not sure if this is considered user error or an actual bug.

[shaise]

Hi. Sorry about that. Indeed having a point in center is problematic since FreeCad regards it as a 2 segment sketch, and it confuses SheetMetal as to which one to use.
I agree, though, that there should be a more descriptive error message for that.

[luzpaz]

@shaise any suggestions for a better title for this ticket ?

[shaise]

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