Problems finding simulation models library

Schematic Simulation (Ngspice)
1

Trying to run a simulation gives me an “Simulation model library not found at [path]”.
The path to the library containing the requested model is defined in Symbol Editor when creating the symbol. After that I started a new schematic in Schematic Editor using this new component. The first OP simulations ran OK, but then the first attempt to run DC sweep throws the error. Kicad seems to search the sim model from the path to the folder containing the schematic appended with the actual sim library path and gives no chance to tell where to find it.

This may have something to do with the fact that I can’t access anything in outside my /home folder from Kicad, which is slightly problematic because all my data files reside in a different disk mounted in /root. The file selection dialog has an address bar to give a location but when I enter the path I get “Folder contents could not be displayed”.

I’m not sure if this a Kicad issue at all or a wxwidgets (?) issue, but in Kicad 8 these worked as expected.

And my system:
Application: KiCad Schematic Editor x86_64 on x86_64
Version: 9.0.0, release build
Libraries:
wxWidgets 3.2.6
FreeType 2.13.3
HarfBuzz 9.0.0
FontConfig 2.15.0
libcurl/8.11.1 OpenSSL/3.3.3 zlib/1.3.1 libidn2/2.3.7 libpsl/0.21.5 nghttp2/1.64.0

Platform: Freedesktop SDK 24.08 (Flatpak runtime), 64 bit, Little endian, wxGTK, X11, KDE, x11
OpenGL: Mesa, AMD CAICOS (DRM 2.50.0 / 6.4.0-150600.23.33-default, LLVM 19.1.7), 4.5 (Compatibility Profile) Mesa 24.3.4 (git-769e51468b)
Build Info:
Date: Feb 21 2025 22:29:54
wxWidgets: 3.2.6 (wchar_t,wx containers) GTK+ 3.24
Boost: 1.87.0
OCC: 7.9.0
Curl: 8.11.1
ngspice: 44.2
Compiler: GCC 14.2.0 with C++ ABI 1019
KICAD_IPC_API=ON
Locale:
Lang:
Enc: UTF-8
Num: 1234.5
Encoded кΩ丈: D0BACEA9E4B888 (sys), D0BACEA9E4B888 (utf8)

Edit/add:
Found a workaround. Within the schematic (containing several copies of the same component), edit the properties of the component itself and assign it a “new” simulation profile, every instance separately, the simulations work again. Redefining just one component only cures that particular copy of the troubled component alone.

2

Checked the behavior again and created a new schematic the same way, using this time another similar component I created at the same time as the previous one and now the simulations work with no problems !? The simulator picks up the correct model from the directory it didn’t find yesterday.
Only thing that happened between these two sessions is a computer shutdown and boot.
Maybe some some temporary hiccup somewhere.

The file selection dialog behavior still has not changed, it can’t find / file system but seems to navigate to some “imaginary” root which is not the actual root filesystem.

But the problem in the subject seems to have cured itself.

3

Isn’t that the way all flatpak images behave? The real file system is sandboxed for security.

4

Haven’t used Flatpak before and vaguely aware that there is something called “sandboxing”. For a moment it flashed in my mind Flatpak might have something to do with it, but then I decided “no”. But it is true then after all.
Taking this into account it’s probably no point in trying to find a fix to other problems with Kicad by upgrading the actual system because Kicad will use the toys it finds in the sandbox anyway.

5

…And, again…
Back to the original original issue.
Opening a schematic created earlier, updating a component by “Edit component properties” > “Update symbol from library” to use an updated (with Symbol Editor) simulation model and trying to run a simulation gives me the “Simulation model library not found at [path]” error again. The difference this time is that even reassigning the updated profile manually to the component in the schematic doesn’t enable simulation.