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-   -   features' edges with surfaceFeatureExtract (http://www.cfd-online.com/Forums/openfoam-meshing-snappyhexmesh/117646-features-edges-surfacefeatureextract.html)

Pj. May 13, 2013 02:25

features' edges with surfaceFeatureExtract
 
Hi everybody,

I'm trying to enhance my mesh using the surfaceFeatureExtract tool, but I can't find a proper guide/tutorial.
I tried to use $FOAM_TUTORIALS/incompressible/pimpleDyMFoam/propeller/Allrun.pre as a guide, but I'm still having some troubles.


I managed to run surfaceFeatureExtract correctly with this command:
Code:

#!/bin/sh

surfaces="
    B0
    spiresFilippo
    block_roughness
"

for s in $surfaces; do
    surfaceFeatureExtract -includedAngle 100 constant/triSurface/$s.stl $s
done

and it generates the .extendedFeatureEdgeMesh and the .eMesh for each surface.

But then what should i do with these files?

I tried to use the .eMesh files as input for snappyHexMesh in place of the .stl, but i receive the error
Code:

unknown file extension eMesh. Supported extensions are '.ftr', '.stl', '.stlb', '.gts', '.obj', '.ac', '.off', '.nas' and '.tri'
So actually I don't know how to proceed.


Moreover in my simulation i need to have different patches for the faces of the B0 volume (it's a box-shape volume). Before using surfaceFeatureExtract I had 5 different .stl for each face that were given to snappyHex as different surfaces. This way i had five different patches.

Now, if i try to use the same five files with surfaceFeatureExtract I receive the error
Code:

Feature line extraction is only valid on closed manifold surfaces.
So how can i keep separated surfaces while using the surfaceFeatureExtract? Can i use the file with the closed volume as input for surfaceFeatureExtract and the five separate surfaces as input for snappyHexMesh?

Thank you very much for the help.


PS: I use OF v2.1, since i saw that the surfaceFeatureExtract has slightly changed from 2.1 to 2.2

Pj. May 13, 2013 03:00

Ok, I looked for a solution for hours and then i found it few minutes after i decided to post here.

Anyway, i write the solution just for a future reference.

A) You can find a quite detailed description of how to use the .eMesh file here https://www.hpc.ntnu.no/display/hpc/...eometryandmesh

B) Yes, just use the joined geometry as input for surfaceFeatureExtract and then use the separated faces for snappyHexMesh. The .eMesh files don't have to be generated using exactly the same .stl files you will give to snappyHex


Sorry for the post. Bye!


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