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How to hex mesh geometry in STL format?

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Old   May 12, 2009, 07:10
Default How to hex mesh geometry in STL format?
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Philip Cardiff
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Hi,


I have geometry in the STL format, and I would like to hex mesh it.


Has any done this before, starting from a STL and finishing with a hex mesh?


Any advice would be much appreciated,
Philip
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Old   May 12, 2009, 07:34
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Hi Philip,

Have you tried snappyHexMesh? It does exactly what you need. Have a look in the User Guide to see how it can be used.

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Jose Santos
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Old   May 12, 2009, 08:26
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Philip Cardiff
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Hi Jose,

I read through snappyHexMesh in the manual.

Is it possible to use snappyHexMesh for meshing the geometry itself, as apposed to around the geometry like in the snappyHesMesh example?

I have a femur (thigh bone) which I would like to mesh.


Thanks for you reply,
If snappyHexMesh suits, that would be great!

Philip
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Old   May 12, 2009, 09:15
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Yes, its possible. You need to define the locationInMesh point in the region you are interested in, ie, inside the femur in you case.

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Old   May 12, 2009, 09:21
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Philip Cardiff
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Jose,


That's great. I didn't realise I could use snappyHexMesh to hex mesh objects.

I shall head off now, and try to learn snappyHexMesh.


Thanks very much for the advice,
it is much appreciated.

Best Regards,
Philip

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Old   June 30, 2009, 22:55
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Hi, Jose,
Now I am facing a weird problem.
I am going to hex mesh the flow field in a screw extruder.
I blockMeshed the barrel back ground . it worked.
I then tried to snappyHexMesh the field between the screw and the barrel.
I defined the location in mesh , but when I run sHM, it always exited with saying:
Point (x x x) is not inside the mesh or on a face or edge.
Bounding box of the mesh-13.1 -13.1 0) (13.1 13.1 197)
I tried several point , even though I pretend to mesh the area inside the screw.
it does so also. I have tried to avoid the point on the face or edge.
I can not solve the problem. Would you give me some hint?
Thank you.

Wendy
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Old   July 1, 2009, 04:37
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Make sure the dimensions of blockMesh and STL meshes are consistent (eg. m or mm). Its hard to help without extra info on your mesh!

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Jose Santos
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Old   July 2, 2009, 11:40
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Now the problem is, when I run sHM, it stops with the error information:
#0 Foam::error:rintStack(Foam::Ostream&) in "/home/xhw/OpenFOAM/OpenFOAM-1.5/lib/linuxGccDPOpt/libOpenFOAM.so"
#1 Foam::sigFpe::sigFpeHandler(int) in "/home/xhw/OpenFOAM/OpenFOAM-1.5/lib/linuxGccDPOpt/libOpenFOAM.so"
#2 Uninterpreted: [0xb8076400]
#3 Foam::meshRefinement::markSurfaceCurvatureRefineme nt(double, int, Foam::List<int> const&, Foam::Field<Foam::Vector<double> > const&, Foam::List<int>&, int&) const in "/home/xhw/OpenFOAM/OpenFOAM-1.5/lib/linuxGccDPOpt/libautoMesh.so"
#4 Foam::meshRefinement::refineCandidates(Foam::Vecto r<double> const&, double, Foam::PtrList<Foam::featureEdgeMesh> const&, Foam::List<int> const&, bool, bool, bool, bool, int, int) const in "/home/xhw/OpenFOAM/OpenFOAM-1.5/lib/linuxGccDPOpt/libautoMesh.so"
#5 Foam::autoRefineDriver::surfaceOnlyRefine(Foam::re finementParameters const&, int) in "/home/xhw/OpenFOAM/OpenFOAM-1.5/lib/linuxGccDPOpt/libautoMesh.so"
#6 Foam::autoRefineDriver::doRefine(Foam::dictionary const&, Foam::refinementParameters const&, bool) in "/home/xhw/OpenFOAM/OpenFOAM-1.5/lib/linuxGccDPOpt/libautoMesh.so"
#7 main in "/home/xhw/OpenFOAM/OpenFOAM-1.5/applications/bin/linuxGccDPOpt/snappyHexMesh"
#8 __libc_start_main in "/lib/tls/i686/cmov/libc.so.6"
#9 Foam::regIOobject::writeObject(Foam::IOstream::str eamFormat, Foam::IOstream::versionNumber, Foam::IOstream::compressionType) const in "/home/xhw/OpenFOAM/OpenFOAM-1.5/applications/bin/linuxGccDPOpt/snappyHexMesh"
Floating point exception

I am considering if it is caused by shortage of memory space?
Thank you.

Wendy
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Old   July 2, 2009, 23:36
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I just tried another simpler case. it is just a cylinder inside a bigger rectangular container.

when sHM for several iterations, it stoped with information: killed.
no sHM results created.
Anybody has such experience?
Thank you.

Wendy
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Old   July 6, 2009, 12:29
Default sHM , refinement level
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I modified refinement level , it worked finally.
but what is the problem that it works well with lower level and doesn't work with higher level? I still want to get better mesh so I would prefer higher refinement level.
Many thanks to any advice.

Wendy
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