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wikstrom June 12, 2009 09:29

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I think there is a serious bug in extrudeMesh. Using the linearNormal model, all cells created become inside out. Extruding with negative thickness produces a valid mesh. (that ofcourse can be moved into the desired place with transformPoints, but this workaraound feels a bit awkward.)

Attacheed is a test case describing this. Run the included with argument negative and positive.


mattijs June 16, 2009 07:21

Hi Niklas,

the normal is indeed reversed. Agree it is probably not logical. I'd rather not change the behaviour in 1.5.x but will in future versions.



sbence December 6, 2009 07:59

extrudeMesh - hexa cells generated?
Dear Foamers,

I am trying to create a 2D mesh to be used in OpenFOAM with snappy. My method is the following:
  1. create a mesh in snappy, thickness should be large enough to have a few nice layers in the middle
  2. create a cellSet containing these nice layers in the middle
  3. create new mesh based on the cellSet with subsetMesh; the new mesh has almost planar patches on the sides
  4. autoPatch and select a face for extrusion
  5. extrudMesh using the right patch
My problem is that the generated mesh contains hexa cells and pyramids as well. So it is not a real extrusion, because the extrusion would result in hexas and wedges only.

Some explanatory screenshots:
Result with snappy:
cellSet from the middle:
new mesh from cellSet:
patch to extrude (why the triangles are not visualized in paraview?):
result mesh with extrudeMesh:
the same visualized in engrid. different colors > different cell types:
pyramids visualized in engrid:
tetras visualized in engrid:

How can I avoid pyramids/tetras?

Thanks for any help!


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