[Problem] FEM CalculiX execute error with modified inp file

[FEA-eng]

Is there an existing issue for this?

• I have searched the existing issues

Problem description

Steps to reproduce:

1. Download this file and change the extension to .FCStd: Execute error.zip
2. Open it in the newest 0.22 weekly build (it uses the newly implemented FEM features)
3. Go to the FEM workbench, double-click on Analysis to activate it. then double-click on SolverCcxTools.
4. Click Write .inp file, then wait and click Edit .inp file
5. Scroll down and replace this:

** Tie Constraints
** ConstraintTie
*TIE, POSITION TOLERANCE=0.1, CYCLIC SYMMETRY, NAME=TIEConstraintTie
TIE_DEPConstraintTie, TIE_INDConstraintTie
*CYCLIC SYMMETRY MODEL, N=8, NGRAPH=8, TIE=TIEConstraintTie, ELSET=Eall
0,0,0,0,0,1

***********************************************************
** At least one step is needed to run an CalculiX analysis of FreeCAD
*STEP
*STATIC


***********************************************************
** Fixed Constraints
** ConstraintFixed
*BOUNDARY
ConstraintFixed,1
ConstraintFixed,2
ConstraintFixed,3


***********************************************************
** Displacement constraint applied
** ConstraintDisplacement
*BOUNDARY
ConstraintDisplacement,1,1,0.0


***********************************************************
** Outputs --> frd file
*NODE FILE
U
*EL FILE
S, E
** outputs --> dat file
** reaction forces for Constraint fixed
*NODE PRINT, NSET=ConstraintFixed, TOTALS=ONLY
RF
** reaction forces for Constraint displacement constraining translation
*NODE PRINT, NSET=ConstraintDisplacement, TOTALS=ONLY
RF


***********************************************************
*END STEP 

***********************************************************
** CalculiX Input file
**   written by    --> FreeCAD 0.22.0
**   written on    --> Fri Feb 16 12:35:23 2024
**   file name     --> Execute error.FCStd
**   analysis name --> Analysis
**
**
***********************************************************
**  About units:
**  See ccx manual, ccx does not know about any unit.
**  Golden rule: The user must make sure that the numbers they provide have consistent units.
**  The user is the FreeCAD calculix writer module ;-)
**
**  The unit system which is used at Guido Dhondt's company: mm, N, s, K
**  Since Length and Mass are connected by Force, if Length is mm the Mass is in t to get N
**  The following units are used to write to inp file:
**
**  Length: mm (this includes the mesh geometry)
**  Mass: t
**  TimeSpan: s
**  Temperature: K
**
**  This leads to:
**  Force: N
**  Pressure: N/mm^2 == MPa (Young's Modulus has unit Pressure)
**  Density: t/mm^3
**  Gravity: mm/s^2
**  Thermal conductivity: t*mm/K/s^3 == as W/m/K == kW/mm/K
**  Specific Heat: mm^2/s^2/K = J/kg/K == kJ/t/K
**

with this:

** Tie Constraints
** ConstraintTie
*TIE, POSITION TOLERANCE=0.1, CYCLIC SYMMETRY, NAME=TIEConstraintTie
TIE_DEPConstraintTie, TIE_INDConstraintTie
*CYCLIC SYMMETRY MODEL, N=8, NGRAPH=8, TIE=TIEConstraintTie, ELSET=Eall
0,0,0,0,0,1

*NODE
20000,0,0,200
20001,0,0,200
*RIGID BODY, NSET=ConstraintDisplacement, REF NODE=20000, ROT NODE=20001
***********************************************************
** At least one step is needed to run an CalculiX analysis of FreeCAD
*STEP
*STATIC


***********************************************************
** Fixed Constraints
** ConstraintFixed
*BOUNDARY
ConstraintFixed,1
ConstraintFixed,2
ConstraintFixed,3


***********************************************************
** Displacement constraint applied
** ConstraintDisplacement
*CLOAD
20001,3,1000


***********************************************************
** Outputs --> frd file
*NODE FILE
U
*EL FILE
S, E
** outputs --> dat file
** reaction forces for Constraint fixed
*NODE PRINT, NSET=ConstraintFixed, TOTALS=ONLY
RF
** reaction forces for Constraint displacement constraining translation
*NODE PRINT, NSET=ConstraintDisplacement, TOTALS=ONLY
RF


***********************************************************
*END STEP 

***********************************************************
** CalculiX Input file
**   written by    --> FreeCAD 0.22.0
**   written on    --> Fri Feb 16 12:25:03 2024
**   file name     --> 
**   analysis name --> Analysis
**
**
***********************************************************
**  About units:
**  See ccx manual, ccx does not know about any unit.
**  Golden rule: The user must make sure that the numbers they provide have consistent units.
**  The user is the FreeCAD calculix writer module ;-)
**
**  The unit system which is used at Guido Dhondt's company: mm, N, s, K
**  Since Length and Mass are connected by Force, if Length is mm the Mass is in t to get N
**  The following units are used to write to inp file:
**
**  Length: mm (this includes the mesh geometry)
**  Mass: t
**  TimeSpan: s
**  Temperature: K
**
**  This leads to:
**  Force: N
**  Pressure: N/mm^2 == MPa (Young's Modulus has unit Pressure)
**  Density: t/mm^3
**  Gravity: mm/s^2
**  Thermal conductivity: t*mm/K/s^3 == as W/m/K == kW/mm/K
**  Specific Heat: mm^2/s^2/K = J/kg/K == kJ/t/K
**

6. Click Save, then Run CalculiX. You will get the following error:

CalculiX execute error: PySide2.QtCore.QProcess.ProcessError.Crashed

The .inp file itself is correct. It uses proper CalculiX syntax and works when submitted in standalone CalculiX outside of FreeCAD. So no idea what's going on here.

Full version info

OS: Windows 10 build 19045
Word size of FreeCAD: 64-bit
Version: 0.22.0dev.35966 (Git)
Build type: Release
Branch: main
Hash: 7f5d89fa1942fec79222e4d173655744037164dc
Python 3.10.13, Qt 5.15.8, Coin 4.0.2, Vtk 9.2.6, OCC 7.6.3
Locale: Polish/Poland (pl_PL)

Subproject(s) affected?

FEM

Anything else?

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[maxwxyz]

Is this a FreeCAD bug or regarding calculix? Does it work when used without FreeCAD?

[FEA-eng]

Is this a FreeCAD bug or regarding calculix? Does it work when used without FreeCAD?

I've mentioned this at the bottom of the issue description - it works in CalculiX itself so it must be a FreeCAD bug. Not even an issue with the ccx binary provided with weekly builds because it works when I submit the input file using that binary. So something must be wrong with the execution procedure in FreeCAD.

[maxwxyz]

I'm not familiar with ccx: is this a normal thing to do in FEM WB to adjust the inp file? Would you consider this a bug or a new feature to be implemented?

[FEA-eng]

I'm not familiar with ccx: is this a normal thing to do in FEM WB to adjust the inp file? Would you consider this a bug or a new feature to be implemented?

It’s normal (that’s why the inp editor is provided) and very useful (many CalculiX features are still not implemented and you can easily use them this way).

This is clearly a bug, errors like this shouldn’t happen at all. Especially since I’ve used the editor in similar ways in the past and it has always been working well.

Unfortunately, I’ve got no idea what can be wrong here. It must be an issue with the code responsible for submitting an analysis from the written and saved input file.

[marioalexis84]

@FEA-eng I can't reproduce this.
The error message should only appear if CalculiX crash or if you stop the process with the stop button.

[FEA-eng]

@FEA-eng I can't reproduce this.

On what OS ? I can't reproduce it on Ubuntu now so maybe it's Windows-specific. I will have to try on other computers with this OS.

OS: Ubuntu 22.04.3 LTS (ubuntu:GNOME/ubuntu)
Word size of FreeCAD: 64-bit
Version: 0.22.0dev.35994 (Git) AppImage
Build type: Release
Branch: main
Hash: 69097667df47b2cc86d8688d2dbb545319e33e68
Python 3.10.13, Qt 5.15.8, Coin 4.0.2, Vtk 9.2.6, OCC 7.6.3
Locale: English/United States (en_US)

[marioalexis84]

On Linux.
Can you reproduce with another example?

[FEA-eng]

I've tried on a different Windows computer and the same error occured. Can someone with Windows confirm ?

I will let you know if I find another example.

[FEA-eng]

@marioalexis84 Ok, it seems to be way less complex than I thought. The error occurs in recent weekly builds on Windows whether the input file was changed or not. Just starting an analysis with Write .inp file and Run CalculiX instead of Run solver calculations causes the error. Can it be caused by #12273 ?

[marioalexis84]

Can it be caused by #12273 ?

It's the most likely. This is clarified in the Qt documentation in relation to a signal delay:

The QProcess object will immediately enter the Starting state. If the process starts successfully, QProcess will emit started(); otherwise, errorOccurred() will be emitted. Do note that on platforms that are able to start child processes synchronously (notably Windows), those signals will be emitted before this function returns and this QProcess object will transition to either QProcess::Running or QProcess::NotRunning state, respectively. On others paltforms, the started() and errorOccurred() signals will be delayed.

I will do the test from a virtual machine with Windows to correct this problem.

[marioalexis84]

@FEA-eng can you share the complete output you get until the error message is printed?

[FEA-eng]

@FEA-eng can you share the complete output you get until the error message is printed?

Sure:

0.0: Check dependencies...
0.1: Write completed.
0.0: CalculiX binary: E:/FreeCAD_weekly-builds-35994-2024-02-16-conda-Windows-x86_64-py310/bin/ccx.exe
0.0: CalculiX input file: C:\Users\NJ\AppData\Local\Temp\fcfem_gc85zoii\FEMMeshGmsh.inp
0.0: Run CalculiX...
0.0: Starting CalculiX...
0.0: CalculiX is running...
0.0: CalculiX execute error: PySide2.QtCore.QProcess.ProcessError.Crashed
0.0: CalculiX stopped.

[marioalexis84]

@FEA-eng I sent to you a message in the forum,