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Tutorial

In this tutorial, we will go through a complete example using Comfor — from input file to result visualization in ParaView.

You will learn how to:

  • Run an existing example provided with Comfor
  • Understand the basic structure of an input file
  • Visualize results in ParaView

Example Overview#

For this tutorial, we will use the Feuilles example, which can be downloaded from the Comfor Download page.

After extracting the archive, the Feuilles folder structure is:

examples/Feuilles/
 ├── Feuilles.txt        # Input file for the simulation
 └── Results_Feuilles/   # Output directory (created after running Comfor)

The input file is Feuilles.txt, which defines the entire model to be simulated.

The Input File#

Here is a simplified version of the Feuilles.txt file:

CONTROL
RUN FROM 0.0 TO 15.0
PRINT EVERY 0.1

MATERIAL TYPE HYPERELASTIC
MAT_HYPER RHO = 0.00001 DAMPING = 5.0 TYPE = OGDEN MU = [ -0.09, 13.9, -0.20 ] ALPHA = [ -13.7, 0.10, 5.06 ]

NODES
1   X= 0.0  Y= 0.0  Z= 0.0  LOAD = GRAVITY
2   X= 1.0  Y= 1.0  Z= 0.0  LOAD = GRAVITY
3   X= 2.0  Y= 2.0  Z= 0.0  LOAD = GRAVITY

ELEMENTS TYPE MEMBRANE_3
1   nodes = [1,2,3] MATERIAL = MAT_HYPER T = 1.0 FACTOR = 10.0 CONTACT = EDGE

Each section (or block) defines a different part of the simulation:

  • CONTROL — defines simulation time and output frequency
  • MATERIAL — defines material properties
  • NODES and ELEMENTS — define the mesh and connectivity
  • CONSTRAINT and LOAD — apply boundary conditions and loads

For the full description of all available blocks, see Input file reference.

Running the Simulation#

Before running the simulation, we move the Comfor executable (.exe) into the example directory. This makes it easier to access the input file directly without specifying a long path.

  1. Open a terminal (or Command Prompt) inside the example folder

  2. Run the executable: 

    comfor.exe

    Note

    Replace comfor.exe with the actual name of your executable file if it is different.

  3. When the program starts, it will ask for the path to the input file. In this example, the input file is located in the Feuilles folder, so type: 

    Feuilles/Feuilles.txt

Comfor will then read the input file and start the simulation.

Running Comfor in the terminal
Running Comfor in the terminal

During execution, Comfor displays information about the simulation progress, for example:

=================================
Elapsed time: 0.23s
Current time: 5.0
Internal energy: 3.24
Kinetic energy: 0.12
=================================

When the computation is finished, a results folder (e.g. Results_Feuilles/) will appear in the same directory. This folder contains the generated .vtk files that can be visualized in ParaView.

Note

It is also possible to keep the executable elsewhere and provide the full path to the input file when prompted. However, moving the .exe into the example folder simplifies the workflow for beginners.

Visualizing Results in ParaView#

To open the results in ParaView:

  1. Launch ParaView
  2. Go to File → Open
  3. Select the directory Results_Feuilles/
  4. Choose all .vtk files
  5. Click Apply

If nothing appears, make sure the “eye” icon next to the dataset is enabled.

Hint

Enable Auto Apply in Edit → Settings → General → Properties Panel Options to automatically apply changes in ParaView.

Opening results in ParaView
Opening the VTK result files in ParaView

You can now play the animation using the playback controls in the VCR bar. The time bar will display the current simulation time.

Next Steps#

You have now completed your first Comfor simulation.

To learn more: