[fidu]

Hi foamers

I want to include a stl file in my case so that I can use it as a porous media later on. However as soon as I run topoSet I get a cellSet with the size 0. The stl file should be ok and closed, so I don't know what I did wrong... Does anyone know what I have to change?

When I run topoSet I get this output:

/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v1806                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : v1806
Arch   : "LSB;label=32;scalar=64"
Exec   : topoSet
Date   : Nov 02 2020
Time   : 10:10:01
Host   : "eu-login-13"
PID    : 12700
I/O    : uncollated
Case   : /cluster/scratch/kaeserd/01.11/tree_in_buildings
nProcs : 1
trapFpe: Floating point exception trapping enabled (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster (fileModificationSkew 10)
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create polyMesh for time = 0

Reading topoSetDict

Time = 0
    mesh not changed.
Created cellSet trees
    Applying source surfaceToCell
    Adding cells in relation to surface "constant/triSurface/trees.stl" ...
    Marked inside/outside using surface orientation in = 0.26 s

    cellSet trees now size 0
End

my topoSetDict is:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      topoSetDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

actions
(

    {
        name    trees;
        type    cellSet;
        action  new;
        source  surfaceToCell;
        sourceInfo
        {
            file  "constant/triSurface/trees.stl";
            useSurfaceOrientation true;  // use closed surface inside/outside
                                          // test (ignores includeCut,
                                          // outsidePoints)
            outsidePoints   ((-99 -99 -99));    // definition of outside
            includeCut      false;               // cells cut by surface
            includeInside   true;               // cells not on outside of surf
            includeOutside  false;              // cells on outside of surf
            nearDistance    -1;                 // cells with centre near surf
                                                // (set to -1 if not used)
            curvature       -100;               // cells within nearDistance
                                                // and near surf curvature
                                                // (set to -100 if not used)           
        }
    }           
);

My workflow so far was:

1. blockMesh
2. surfaceFeatureExtract
3. snappyHexMesh -overwrite
4. topoSet

Many thanks already in advance for time and help. I hope this problem was not already discussed or if it was you could point me to he tread.

Best

David

[RGS]

I think the problem here is that you are using an STL file. Doesn't OpenFOAM require meshes in it's own format?

[Yann]

Hello,



SurfaceToCell is indeed meant to be used with a STL file as a source.

Here is the documentation for OpenFOAM-v2006 : https://www.openfoam.com/documentati...aceToCell.html

I am not sure what is going on with fidu's error. topoSet gets the file and do the operation without any error so it seems there is no syntax error in topoSetDict. The workflow is fine too.

What you can do :

• Open the mesh with paraview and open your trees.stl file :
  • Check if the STL file is properly positioned and scaled inside your mesh.
  • Do you have cells entirely contained inside the volume defined by your STL file? (with your setup topoSet will keep only the cells inside the STL)
• Run surfaceCheck on your STL files to check for any error. I think topoSet would fail if the STL was not closed but you can always check.

Hope this helps,
Yann

[fidu]

Originally Posted by Yann

Hello,



SurfaceToCell is indeed meant to be used with a STL file as a source.

Here is the documentation for OpenFOAM-v2006 : https://www.openfoam.com/documentati...aceToCell.html

I am not sure what is going on with fidu's error. topoSet gets the file and do the operation without any error so it seems there is no syntax error in topoSetDict. The workflow is fine too.

What you can do :

• Open the mesh with paraview and open your trees.stl file :
  • Check if the STL file is properly positioned and scaled inside your mesh.
  • Do you have cells entirely contained inside the volume defined by your STL file? (with your setup topoSet will keep only the cells inside the STL)
• Run surfaceCheck on your STL files to check for any error. I think topoSet would fail if the STL was not closed but you can always check.

Hope this helps,
Yann

Thanks a lot! I did not have a fine enough mesh to capture the stl file.

Best
fidu