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optimize snapping

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Old   February 16, 2010, 12:02
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Yes, I think ICON has some of the feature . .. I hope they "OpenFOAM" release them for everyone sometime in future ..

I'm sure snappyHexMesh is more capable and can do edge capturing etc... But I'm just waiting those feature to be released ...

I'm still wondering which software foam_noob has used to create those images ... They looks from paraview ... as he is saying as well... if thats true then HOW ??
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Old   February 16, 2010, 15:53
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Vincent RIVOLA
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yes they are coming from paraview I think. But it's not a cut inside the mesh, it's only the symmetryPlane.
Since the cells are not cut, they are displayed correctly by paraview. it wouldn't be the case as you experienced if the surface was a slice in the middle of the field.
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Old   February 16, 2010, 16:47
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yup that make sense .. I guess i missed to read that ... You are right thanks
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Old   February 16, 2010, 18:28
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Picture in Paraview get better if you do not create a slice (this triangulates) but use "ExtractCellsByRegion" with reion plane and "Extract intersected only". Works fine for me.

Regards.
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Old   February 16, 2010, 20:40
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"ExtractCellsByRegion" approach works great Thanks

Quote:
Originally Posted by bastil View Post
Picture in Paraview get better if you do not create a slice (this triangulates) but use "ExtractCellsByRegion" with reion plane and "Extract intersected only". Works fine for me.

Regards.
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Old   February 17, 2010, 03:47
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Patrick Wang
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Thx Bastil for the "extractcellsbyregion" tip. These cuts look a lot better than the one from the slice function.

@ tachyon_me, sorry that it took me so long to reply. As vinz already mentioned, it's the symmetry Plane.
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Old   February 17, 2010, 05:27
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Simon Rees
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Further to my comment about vtk not being able to show polyhedra, I tried visualising a mesh with Tecplot and this does show polyhedra. It is consequently easier to see how cells are subdivied by SHM.
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Old   February 17, 2010, 11:17
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Thank you Patrick W and Bastil .

It's really close to what I wanted to see from paraview... for a long time ...

Have anyone also tried keyframe animation with paraview. I normally use Ensight to do keyframe animation with fully automated scripting ...

I like paraview and wanted to see how close i can get with doing all things which may be on the way for post-processing ..

I guess flip book animation works good and easy to setup in paraview but never tried keyframes ...
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Old   August 2, 2010, 07:46
Default the minVol-setting influences the snapping
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Axel Tietjen
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Hi,

What I found out is that the minVol parameter can be the reason for those bumpy surfaces, too.

I use minVol to avoid too small cells, which can be created during the snapping-phase otherwise. As I understand this parameter, sHM checks this limit while moving the grid-points towards the surface. If the volume of the cells containing the moved points gets too low, sHM leaves the point where it is. This gives a slightly bumpy surface.
But if there is a too high Value of minVol, sHM might leave the surface almost "unsnapped".

To get a proper setting for minVol, I calculate: initial cellVolume / 8^refinementLevels , wich is the min castellated cellVolume. This further divided by about 20 is a good value for minVol.

Regards,
Axel
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