[MartinBlx]

Hello everyone,

I'm comparing the efficiency of different snappyHexMesh meshes and to do so I'm paying attention to the number of cells of the mesh. And I made the weird discovery that checkMesh and ParaView don't agree on the number of cells of the mesh!

For example, for the same mesh, the Statistics inspector of ParaView gives 3.995.096 cells:

https://drive.google.com/file/d/0B_T...ew?usp=sharing

While the checkMesh result gives 1.105.136 cells:

Create time

Create polyMesh for time = 0

Time = 0

Mesh stats
    points:           1593493
    faces:            3707462
    internal faces:   3262532
    cells:            1105136
    faces per cell:   6.3069106
    boundary patches: 3
    point zones:      0
    face zones:       0
    cell zones:       0

Which one should I trust?

And any explanations for this huge difference? I have compared several meshes and the ratio is typically around 4 in favor of ParaView everytime.

Martin

[user10600]

Hello everyone !

I have noticed exactly the same thing a few days ago! Does someone has an idea why there is such a difference ?

I would tend to trust more the data informations given by "checkMesh", but should I ?


Thanks in advance.

[Antimony]

Hi,

If I remember correctly (unfortunately I can't remember where I read it though), Paraview and the rest can't handle polyhedral cells, and instead decompose it to tets and the like.

Consequently the number reported by Paraview would be higher, because of this decomposition.

If I can find the link to the post on this, I will put it here.

Hope this helps.

Cheers,
Antimony

[user10600]

Wow it makes sense!

Thanks a lot!

[himanshu28]

Originally Posted by Antimony

Hi,

If I remember correctly (unfortunately I can't remember where I read it though), Paraview and the rest can't handle polyhedral cells, and instead decompose it to tets and the like.

Consequently the number reported by Paraview would be higher, because of this decomposition.

If I can find the link to the post on this, I will put it here.

Hope this helps.

Cheers,
Antimony

Hi Antimony,

Did you find the link.

Thank you.

[Traction]

Originally Posted by himanshu28

Hi Antimony,

Did you find the link.

Thank you.

Hey,
this topic has been analyzed here (with a few examples as well): Exporting mesh for an OpenFOAM chtMultiRegion case