[snappyHexMesh] snappyHexMesh decomposition error

johnsmith332 · February 27, 2012, 01:16

Hi, I'm pretty new at OpenFOAM and I'm trying to so a dsmcFoam simuation using a mesh created with snappyHexMesh. The mesh looks fine in ParaView but I get warnings when I run dsmcInitialise, and the same warnings when I run the simulation which cause it to crash. The error says:

--> FOAM Warning :
From function Foam::List<Foam::FixedList<Foam::label, 4> >Foam::Cloud<ParticleType>::faceTetIndices(label fI, label cI) const
in file meshes/polyMesh/polyMeshTetDecomposition/polyMeshTetDecomposition.C at line 561
No base point for face 25085, 3(3298 2596 2567), produces a valid tet decomposition.

Another warning says:

No base point for face xxxxx, (xxxx)produces a decomposition that has a minimum volume greater than tolerance

I've looked all over the place trying to figure out what's causing this error but with no luck. Does anyone know what this error means or how I might fix it?

e.ahmadiyan · April 8, 2013, 02:53

Hi dear johnsmith332
I have same problem as you too. Could you help me to resolve it.
Thanks in advance.
Best regards.

e.ahmadiyan

jackeyhust · June 25, 2013, 11:33

hi, Esmaeil and John,

have you found the way to solve this problem above? Could you give me a hint for it ? thank you!

best regards,

Jackie

Ramsky · July 29, 2013, 09:57

Looks like the problem is with face tets.

If your mesh is generated with snappyHexMesh, try the following:

In snappyhexMeshDict file, look for "minTetQuality".

//- Minimum quality of the tet formed by the face-centre
// and variable base point minimum decomposition triangles and
// the cell centre. Set to very negative number (e.g. -1E30) to
// disable.
// <0 = inside out tet,
// 0 = flat tet
// 1 = regular tet

For a regular tet, it should be positive. Try setting it to 1. If it does not work, set it to a very low positive number. Say 1e-10.

One way to check whether the issue with face tet is resolved or not before the start of the simulation is to do an "checkMesh -allGeometry". It will report if there are any issues with face tets.

Hope this helps.

ramsky

manuelffonseca · April 7, 2017, 22:56

hi, have you used first the blockmesh command? i had the same error and it was because i forgot to execute the blockmesh...

February 27, 2012, 01:16	snappyHexMesh decomposition error	#1
johnsmith332 New Member John Smith Join Date: Feb 2012 Posts: 4 Rep Power: 14	Hi, I'm pretty new at OpenFOAM and I'm trying to so a dsmcFoam simuation using a mesh created with snappyHexMesh. The mesh looks fine in ParaView but I get warnings when I run dsmcInitialise, and the same warnings when I run the simulation which cause it to crash. The error says: --> FOAM Warning : From function Foam::List<Foam::FixedList<Foam::label, 4> >Foam::Cloud<ParticleType>::faceTetIndices(label fI, label cI) const in file meshes/polyMesh/polyMeshTetDecomposition/polyMeshTetDecomposition.C at line 561 No base point for face 25085, 3(3298 2596 2567), produces a valid tet decomposition. Another warning says: No base point for face xxxxx, (xxxx)produces a decomposition that has a minimum volume greater than tolerance I've looked all over the place trying to figure out what's causing this error but with no luck. Does anyone know what this error means or how I might fix it? e.ahmadiyan likes this.

July 29, 2013, 09:57		#4
Ramsky New Member Join Date: Jul 2013 Posts: 8 Rep Power: 12	Looks like the problem is with face tets. If your mesh is generated with snappyHexMesh, try the following: In snappyhexMeshDict file, look for "minTetQuality". //- Minimum quality of the tet formed by the face-centre // and variable base point minimum decomposition triangles and // the cell centre. Set to very negative number (e.g. -1E30) to // disable. // <0 = inside out tet, // 0 = flat tet // 1 = regular tet For a regular tet, it should be positive. Try setting it to 1. If it does not work, set it to a very low positive number. Say 1e-10. One way to check whether the issue with face tet is resolved or not before the start of the simulation is to do an "checkMesh -allGeometry". It will report if there are any issues with face tets. Hope this helps. ramsky Mojtaba.a, PonchO and alsaeng like this.

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April 8, 2013, 02:53		#2
e.ahmadiyan New Member Esmaeil Ahmadiyan Join Date: Sep 2011 Posts: 26 Rep Power: 14	Hi dear johnsmith332 I have same problem as you too. Could you help me to resolve it. Thanks in advance. Best regards. e.ahmadiyan

June 25, 2013, 11:33		#3
jackeyhust New Member Jackie Chou Join Date: Mar 2013 Posts: 12 Rep Power: 13	hi, Esmaeil and John, have you found the way to solve this problem above? Could you give me a hint for it ? thank you! best regards, Jackie

April 7, 2017, 22:56		#5
manuelffonseca New Member Manuel Fermin Fonseca Join Date: Nov 2014 Location: Valencia, Venezuela Posts: 18 Rep Power: 11	hi, have you used first the blockmesh command? i had the same error and it was because i forgot to execute the blockmesh...