Bug#1118446: freecad: Freecad segfault on creating mesh from body

Michele Cane michele.cane at gmail.com
Mon Oct 20 09:45:04 BST 2025 

Package: freecad
Version: 1.0.2+dfsg-2
Severity: normal

Dear Maintainer,

When creating a mesh from a body or sets of bodies, FreeCAD segfaults with the below back trace.

The issue does not arrise with AppImage 1.0.2 or 1.1.0dev (latest).

Best regards

Mike

[tempestus:17713:0:17713] Caught signal 11 (Segmentation fault: address not mapped to object at address (nil))
==== backtrace (tid:  17713) ====
 0  /lib/x86_64-linux-gnu/libucs.so.0(ucs_handle_error+0x2bc) [0x7f17000b071c]
 1  /lib/x86_64-linux-gnu/libucs.so.0(+0x328fd) [0x7f17000b08fd]
 2  /lib/x86_64-linux-gnu/libucs.so.0(+0x32aca) [0x7f17000b0aca]
 3  /lib/x86_64-linux-gnu/libc.so.6(+0x3fdf0) [0x7f17dbc49df0]
 4  /lib/x86_64-linux-gnu/libnglib.so.6.2(_ZNK6netgen11OCCGeometry7GetEdgeERK12TopoDS_Shape+0x4a) [0x7f16f0e903ea]
 5  /lib/x86_64-linux-gnu/libnglib.so.6.2(_ZN6netgen19OCCSetLocalMeshSizeERKNS_11OCCGeometryERNS_4MeshERKNS_17MeshingParametersERKNS_13OCCParametersE+0x1055) [0x7f16f0e86c75]
 6  /lib/x86_64-linux-gnu/libnglib.so.6.2(_ZN6netgen14NetgenGeometry12GenerateMeshERSt10shared_ptrINS_4MeshEERNS_17MeshingParametersE+0x3b4) [0x7f16f0d7c774]
 7  /usr/lib/freecad-python3/lib/libNETGENPlugin.so(_ZN6netgen15OCCGenerateMeshERNS_11OCCGeometryERSt10shared_ptrINS_4MeshEERNS_17MeshingParametersE+0x2b) [0x7f174844f31b]
 8  /usr/lib/freecad-python3/lib/libNETGENPlugin.so(_ZN19NETGENPlugin_Mesher7ComputeEv+0x363) [0x7f1748444b33]
 9  /usr/lib/freecad-python3/lib/libNETGENPlugin.so(_ZN22NETGENPlugin_NETGEN_2D7ComputeER10SMESH_MeshRK12TopoDS_Shape+0xb3) [0x7f174844ddf3]
10  /usr/lib/freecad-python3/lib/libSMESH.so(_ZN13SMESH_subMesh18ComputeStateEngineEi+0xaf8) [0x7f16f165d238]
11  /usr/lib/freecad-python3/lib/libSMESH.so(_ZN9SMESH_Gen7ComputeER10SMESH_MeshRK12TopoDS_Shapebb13MeshDimensionPSt3setIiSt4lessIiESaIiEE+0x7e6) [0x7f16f159af26]
12  /usr/lib/freecad-python3/lib/MeshPart.so(_ZNK8MeshPart6Mesher10createMeshEv+0x13b) [0x7f17488e9bab]
13  /usr/lib/freecad-python3/lib/MeshPart.so(+0x367fa) [0x7f17488c37fa]
14  /usr/lib/freecad-python3/lib/MeshPart.so(_ZN8MeshPart6Module13meshFromShapeERKN2Py5TupleERKNS1_4DictE+0xfa4) [0x7f17488c7c64]
15  /usr/lib/freecad-python3/lib/MeshPart.so(_ZN2Py15ExtensionModuleIN8MeshPart6ModuleEE21invoke_method_keywordEPvRKNS_5TupleERKNS_4DictE+0x3c) [0x7f17488c2f6c]
16  /usr/lib/freecad-python3/lib/libFreeCADBase.so(method_keyword_call_handler+0x219) [0x7f17de0efc89]
17  /lib/x86_64-linux-gnu/libpython3.13.so.1.0(+0x172102) [0x7f17dd972102]
18  /lib/x86_64-linux-gnu/libpython3.13.so.1.0(_PyObject_MakeTpCall+0x19a) [0x7f17dd914c9a]
19  /lib/x86_64-linux-gnu/libpython3.13.so.1.0(_PyEval_EvalFrameDefault+0x28ee) [0x7f17dda573ce]
20  /lib/x86_64-linux-gnu/libpython3.13.so.1.0(PyEval_EvalCode+0xe0) [0x7f17dda54a00]
21  /lib/x86_64-linux-gnu/libpython3.13.so.1.0(+0x2ddaaa) [0x7f17ddaddaaa]
22  /lib/x86_64-linux-gnu/libpython3.13.so.1.0(+0x2dde49) [0x7f17ddadde49]
23  /lib/x86_64-linux-gnu/libpython3.13.so.1.0(PyRun_StringFlags+0x75) [0x7f17ddade8d5]
24  /usr/lib/freecad-python3/lib/libFreeCADBase.so(_ZN4Base20InterpreterSingleton9runStringB5cxx11EPKc+0x6a) [0x7f17de156fca]
25  /usr/lib/freecad-python3/lib/libFreeCADGui.so(_ZN3Gui7Command11_runCommandEPKciNS0_10DoCmd_TypeES2_+0x96) [0x7f17df2f8626]
26  /usr/lib/freecad-python3/lib/MeshPartGui.so(_ZN11MeshPartGui12Tessellation7processEiPN3App8DocumentERKNSt7__cxx114listINS1_10SubObjectTESaIS6_EEE+0x2d1) [0x7f174854a3b1]
27  /usr/lib/freecad-python3/lib/MeshPartGui.so(_ZN11MeshPartGui12Tessellation6acceptEv+0x2f4) [0x7f174854ac64]
28  /usr/lib/freecad-python3/lib/libFreeCADGui.so(_ZN3Gui8TaskView8TaskView6acceptEv+0x63) [0x7f17df6e0873]
29  /lib/x86_64-linux-gnu/libQt5Core.so.5(+0x3256e9) [0x7f17dc5256e9]
30  /lib/x86_64-linux-gnu/libQt5Widgets.so.5(+0x30e6c8) [0x7f17dd30e6c8]
31  /lib/x86_64-linux-gnu/libQt5Core.so.5(+0x3256bd) [0x7f17dc5256bd]
32  /lib/x86_64-linux-gnu/libQt5Widgets.so.5(_ZN15QAbstractButton7clickedEb+0x46) [0x7f17dd25e8d6]
33  /lib/x86_64-linux-gnu/libQt5Widgets.so.5(+0x25eb4e) [0x7f17dd25eb4e]
34  /lib/x86_64-linux-gnu/libQt5Widgets.so.5(+0x2607af) [0x7f17dd2607af]
35  /lib/x86_64-linux-gnu/libQt5Widgets.so.5(_ZN15QAbstractButton17mouseReleaseEventEP11QMouseEvent+0x129) [0x7f17dd2609d9]
36  /lib/x86_64-linux-gnu/libQt5Widgets.so.5(_ZN7QWidget5eventEP6QEvent+0x308) [0x7f17dd1a72d8]
37  /lib/x86_64-linux-gnu/libQt5Widgets.so.5(_ZN19QApplicationPrivate13notify_helperEP7QObjectP6QEvent+0x80) [0x7f17dd164240]
38  /lib/x86_64-linux-gnu/libQt5Widgets.so.5(_ZN12QApplication6notifyEP7QObjectP6QEvent+0x1351) [0x7f17dd16bba1]
39  /usr/lib/freecad-python3/lib/libFreeCADGui.so(_ZN3Gui14GUIApplication6notifyEP7QObjectP6QEvent+0xc8) [0x7f17df29c6a8]
40  /lib/x86_64-linux-gnu/libQt5Core.so.5(_ZN16QCoreApplication15notifyInternal2EP7QObjectP6QEvent+0x128) [0x7f17dc4e94c8]
41  /lib/x86_64-linux-gnu/libQt5Widgets.so.5(_ZN19QApplicationPrivate14sendMouseEventEP7QWidgetP11QMouseEventS1_S1_PS1_R8QPointerIS0_Ebb+0x1c4) [0x7f17dd169c24]
42  /lib/x86_64-linux-gnu/libQt5Widgets.so.5(+0x1c1e2a) [0x7f17dd1c1e2a]
43  /lib/x86_64-linux-gnu/libQt5Widgets.so.5(+0x1c52ff) [0x7f17dd1c52ff]
44  /lib/x86_64-linux-gnu/libQt5Widgets.so.5(_ZN19QApplicationPrivate13notify_helperEP7QObjectP6QEvent+0x80) [0x7f17dd164240]
45  /usr/lib/freecad-python3/lib/libFreeCADGui.so(_ZN3Gui14GUIApplication6notifyEP7QObjectP6QEvent+0xc8) [0x7f17df29c6a8]
46  /lib/x86_64-linux-gnu/libQt5Core.so.5(_ZN16QCoreApplication15notifyInternal2EP7QObjectP6QEvent+0x128) [0x7f17dc4e94c8]
47  /lib/x86_64-linux-gnu/libQt5Gui.so.5(_ZN22QGuiApplicationPrivate17processMouseEventEPN29QWindowSystemInterfacePrivate10MouseEventE+0xc53) [0x7f17dc9469f3]
48  /lib/x86_64-linux-gnu/libQt5Gui.so.5(_ZN22QWindowSystemInterface22sendWindowSystemEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE+0xab) [0x7f17dc9163fb]
49  /lib/x86_64-linux-gnu/libQt5WaylandClient.so.5(+0xb4ce4) [0x7f17d5c61ce4]
50  /lib/x86_64-linux-gnu/libglib-2.0.so.0(+0x5c6ae) [0x7f17da1006ae]
51  /lib/x86_64-linux-gnu/libglib-2.0.so.0(+0x5fa4f) [0x7f17da103a4f]
52  /lib/x86_64-linux-gnu/libglib-2.0.so.0(g_main_context_iteration+0x30) [0x7f17da1041d0]
53  /lib/x86_64-linux-gnu/libQt5Core.so.5(_ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE+0x4a) [0x7f17dc54770a]
54  /lib/x86_64-linux-gnu/libQt5Core.so.5(_ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE+0x11a) [0x7f17dc4e7dfa]
55  /lib/x86_64-linux-gnu/libQt5Core.so.5(_ZN16QCoreApplication4execEv+0x8f) [0x7f17dc4f09af]
56  /usr/lib/freecad-python3/lib/libFreeCADGui.so(_ZN3Gui11Application14runApplicationEv+0xbab) [0x7f17df1b0e9b]
57  freecad(+0x8dd9) [0x560f638cddd9]
58  /lib/x86_64-linux-gnu/libc.so.6(+0x29ca8) [0x7f17dbc33ca8]
59  /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x85) [0x7f17dbc33d65]
60  freecad(+0x91d1) [0x560f638ce1d1]
=================================
Program received signal SIGSEGV, Segmentation fault.
#0  /lib/x86_64-linux-gnu/libc.so.6(+0x3fdf0) [0x7f17dbc49df0]
#1  0x7f16f0e903ea in netgen::OCCGeometry::GetEdge(TopoDS_Shape const&) const from /lib/x86_64-linux-gnu/libnglib.so.6.2+0x4a
#2  0x7f16f0e86c75 in netgen::OCCSetLocalMeshSize(netgen::OCCGeometry const&, netgen::Mesh&, netgen::MeshingParameters const&, netgen::OCCParameters const&) from /lib/x86_64-linux-gnu/libnglib.so.6.2+0x1055
#3  0x7f16f0d7c774 in netgen::NetgenGeometry::GenerateMesh(std::shared_ptr<netgen::Mesh>&, netgen::MeshingParameters&) from /lib/x86_64-linux-gnu/libnglib.so.6.2+0x3b4
#4  0x7f174844f31b in netgen::OCCGenerateMesh(netgen::OCCGeometry&, std::shared_ptr<netgen::Mesh>&, netgen::MeshingParameters&) from /usr/lib/freecad-python3/lib/libNETGENPlugin.so+0x2b
#5  0x7f1748444b33 in NETGENPlugin_Mesher::Compute() from /usr/lib/freecad-python3/lib/libNETGENPlugin.so+0x363
#6  0x7f174844ddf3 in NETGENPlugin_NETGEN_2D::Compute(SMESH_Mesh&, TopoDS_Shape const&) from /usr/lib/freecad-python3/lib/libNETGENPlugin.so+0xb3
#7  0x7f16f165d238 in SMESH_subMesh::ComputeStateEngine(int) from /usr/lib/freecad-python3/lib/libSMESH.so+0xaf8
#8  0x7f16f159af26 in SMESH_Gen::Compute(SMESH_Mesh&, TopoDS_Shape const&, bool, bool, MeshDimension, std::set<int, std::less<int>, std::allocator<int> >*) from /usr/lib/freecad-python3/lib/libSMESH.so+0x7e6
#9  0x7f17488e9bab in MeshPart::Mesher::createMesh() const from /usr/lib/freecad-python3/lib/MeshPart.so+0x13b
#10  /usr/lib/freecad-python3/lib/MeshPart.so(+0x367fa) [0x7f17488c37fa]
#11  0x7f17488c7c64 in MeshPart::Module::meshFromShape(Py::Tuple const&, Py::Dict const&) from /usr/lib/freecad-python3/lib/MeshPart.so+0xfa4
#12  0x7f17488c2f6c in Py::ExtensionModule<MeshPart::Module>::invoke_method_keyword(void*, Py::Tuple const&, Py::Dict const&) from /usr/lib/freecad-python3/lib/MeshPart.so+0x3c
#13  /usr/lib/freecad-python3/lib/libFreeCADBase.so(method_keyword_call_handler+0x219) [0x7f17de0efc89]
#14  /lib/x86_64-linux-gnu/libpython3.13.so.1.0(+0x172102) [0x7f17dd972102]
#15  /lib/x86_64-linux-gnu/libpython3.13.so.1.0(_PyObject_MakeTpCall+0x19a) [0x7f17dd914c9a]
#16  /lib/x86_64-linux-gnu/libpython3.13.so.1.0(_PyEval_EvalFrameDefault+0x28ee) [0x7f17dda573ce]
#17  /lib/x86_64-linux-gnu/libpython3.13.so.1.0(PyEval_EvalCode+0xe0) [0x7f17dda54a00]
#18  /lib/x86_64-linux-gnu/libpython3.13.so.1.0(+0x2ddaaa) [0x7f17ddaddaaa]
#19  /lib/x86_64-linux-gnu/libpython3.13.so.1.0(+0x2dde49) [0x7f17ddadde49]
#20  /lib/x86_64-linux-gnu/libpython3.13.so.1.0(PyRun_StringFlags+0x75) [0x7f17ddade8d5]
#21  0x7f17de156fca in Base::InterpreterSingleton::runString[abi:cxx11](char const*) from /usr/lib/freecad-python3/lib/libFreeCADBase.so+0x6a
#22  0x7f17df2f8626 in Gui::Command::_runCommand(char const*, int, Gui::Command::DoCmd_Type, char const*) from /usr/lib/freecad-python3/lib/libFreeCADGui.so+0x96
#23  0x7f174854a3b1 in MeshPartGui::Tessellation::process(int, App::Document*, std::__cxx11::list<App::SubObjectT, std::allocator<App::SubObjectT> > const&) from /usr/lib/freecad-python3/lib/MeshPartGui.so+0x2d1
#24  0x7f174854ac64 in MeshPartGui::Tessellation::accept() from /usr/lib/freecad-python3/lib/MeshPartGui.so+0x2f4
#25  0x7f17df6e0873 in Gui::TaskView::TaskView::accept() from /usr/lib/freecad-python3/lib/libFreeCADGui.so+0x63
#26  /lib/x86_64-linux-gnu/libQt5Core.so.5(+0x3256e9) [0x7f17dc5256e9]
#27  /lib/x86_64-linux-gnu/libQt5Widgets.so.5(+0x30e6c8) [0x7f17dd30e6c8]
#28  /lib/x86_64-linux-gnu/libQt5Core.so.5(+0x3256bd) [0x7f17dc5256bd]
#29  0x7f17dd25e8d6 in QAbstractButton::clicked(bool) from /lib/x86_64-linux-gnu/libQt5Widgets.so.5+0x46
#30  /lib/x86_64-linux-gnu/libQt5Widgets.so.5(+0x25eb4e) [0x7f17dd25eb4e]
#31  /lib/x86_64-linux-gnu/libQt5Widgets.so.5(+0x2607af) [0x7f17dd2607af]
#32  0x7f17dd2609d9 in QAbstractButton::mouseReleaseEvent(QMouseEvent*) from /lib/x86_64-linux-gnu/libQt5Widgets.so.5+0x129
#33  0x7f17dd1a72d8 in QWidget::event(QEvent*) from /lib/x86_64-linux-gnu/libQt5Widgets.so.5+0x308
#34  0x7f17dd164240 in QApplicationPrivate::notify_helper(QObject*, QEvent*) from /lib/x86_64-linux-gnu/libQt5Widgets.so.5+0x80
#35  0x7f17dd16bba1 in QApplication::notify(QObject*, QEvent*) from /lib/x86_64-linux-gnu/libQt5Widgets.so.5+0x1351
#36  0x7f17df29c6a8 in Gui::GUIApplication::notify(QObject*, QEvent*) from /usr/lib/freecad-python3/lib/libFreeCADGui.so+0xc8
#37  0x7f17dc4e94c8 in QCoreApplication::notifyInternal2(QObject*, QEvent*) from /lib/x86_64-linux-gnu/libQt5Core.so.5+0x128
#38  0x7f17dd169c24 in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&, bool, bool) from /lib/x86_64-linux-gnu/libQt5Widgets.so.5+0x1c4
#39  /lib/x86_64-linux-gnu/libQt5Widgets.so.5(+0x1c1e2a) [0x7f17dd1c1e2a]
#40  /lib/x86_64-linux-gnu/libQt5Widgets.so.5(+0x1c52ff) [0x7f17dd1c52ff]
#41  0x7f17dd164240 in QApplicationPrivate::notify_helper(QObject*, QEvent*) from /lib/x86_64-linux-gnu/libQt5Widgets.so.5+0x80
#42  0x7f17df29c6a8 in Gui::GUIApplication::notify(QObject*, QEvent*) from /usr/lib/freecad-python3/lib/libFreeCADGui.so+0xc8
#43  0x7f17dc4e94c8 in QCoreApplication::notifyInternal2(QObject*, QEvent*) from /lib/x86_64-linux-gnu/libQt5Core.so.5+0x128
#44  0x7f17dc9469f3 in QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::MouseEvent*) from /lib/x86_64-linux-gnu/libQt5Gui.so.5+0xc53
#45  0x7f17dc9163fb in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) from /lib/x86_64-linux-gnu/libQt5Gui.so.5+0xab
#46  /lib/x86_64-linux-gnu/libQt5WaylandClient.so.5(+0xb4ce4) [0x7f17d5c61ce4]
#47  /lib/x86_64-linux-gnu/libglib-2.0.so.0(+0x5c6ae) [0x7f17da1006ae]
#48  /lib/x86_64-linux-gnu/libglib-2.0.so.0(+0x5fa4f) [0x7f17da103a4f]
#49  /lib/x86_64-linux-gnu/libglib-2.0.so.0(g_main_context_iteration+0x30) [0x7f17da1041d0]
#50  0x7f17dc54770a in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) from /lib/x86_64-linux-gnu/libQt5Core.so.5+0x4a
#51  0x7f17dc4e7dfa in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) from /lib/x86_64-linux-gnu/libQt5Core.so.5+0x11a
#52  0x7f17dc4f09af in QCoreApplication::exec() from /lib/x86_64-linux-gnu/libQt5Core.so.5+0x8f
#53  0x7f17df1b0e9b in Gui::Application::runApplication() from /usr/lib/freecad-python3/lib/libFreeCADGui.so+0xbab
#54  freecad(+0x8dd9) [0x560f638cddd9]
#55  /lib/x86_64-linux-gnu/libc.so.6(+0x29ca8) [0x7f17dbc33ca8]
#56  /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x85) [0x7f17dbc33d65]
#57  freecad(+0x91d1) [0x560f638ce1d1]



-- System Information:
Debian Release: forky/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 6.16.12+deb14-amd64 (SMP w/8 CPU threads; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages freecad depends on:
ii  freecad-python3  1.0.2+dfsg-2
ii  python3          3.13.7-1

Versions of packages freecad recommends:
pn  calculix-ccx        <none>
ii  graphviz            2.42.4-3
ii  python3-opencamlib  2023.01.11-5+b3

Versions of packages freecad suggests:
pn  povray  <none>

-- no debconf information

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