[GiDlist] bug in mesher

[Mark Smith]

GiD 6.3.0b win98

Dear GiD team
I have discovered a bug in the unstructured mesher when generating quadratic
tetrahedra.
The mesh looks OK in GiD but here no mid-side nodes are displayed. Using a
routine I convert the quadratic mesh into line elements then re-import into
GiD to display the quadratic mesh, This is when it becomes obvious that
there are errors with the node connectivity. see attached gifs.
The error seems to be mesh parameter dependant, so far I have only found
problems with settings RFast & Smoothing high angle but as I say The linear
mesh displayed in GiD looks OK !!!!
I am also sure that it isn't an error in my routine as looking at the mesh
file shows the wrong node numbering for the offending elements.
Also attached a simple sphere meshing problem which gives the error.





Displayed mesh.gif actual quad mesh.gif meshbug.gid.zip


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[Miguel A. de Riera Pasenau]

Hello,
thanks, i discovered the error too this weekend when i
implemented the drawing of the quadratic elements,
we are working on it.
the problem is that some middle nodes 'jump' from
the surface they should be to another one, as you
can see in the attached file.

try with the 'automatic correct sizes' switch on, and
a smaller element size.
best regards

miguel

Mark Smith wrote:

GiD 6.3.0b win98

Dear GiD team
I have discovered a bug in the unstructured mesher when generating quadratic
tetrahedra.
The mesh looks OK in GiD but here no mid-side nodes are displayed. Using a
routine I convert the quadratic mesh into line elements then re-import into
GiD to display the quadratic mesh, This is when it becomes obvious that
there are errors with the node connectivity. see attached gifs.
The error seems to be mesh parameter dependant, so far I have only found
problems with settings RFast & Smoothing high angle but as I say The linear
mesh displayed in GiD looks OK !!!!
I am also sure that it isn't an error in my routine as looking at the mesh
file shows the wrong node numbering for the offending elements.
Also attached a simple sphere meshing problem which gives the error.

Displayed mesh.gif actual quad mesh.gif meshbug.gid.zip

--------------------------------------------------------------------------
Linx Printing Technologies plc
+44 (0)1480302100
http://www.linx.co.uk/
This e-mail may contain privileged/confidential information and may be
read, copied and used only by the intended recipient. If you have received
it in error, please contact the sender by return e-mail or by
telephoning +44 (0)1480 302100.
Please then delete the e-mail and do not disclose its contents to any
person.

Any information in this message that does not relate to the official
business of Linx shall be understood as neither given nor endorsed by Linx.
We reserve the right to monitor all e-mail communications through our
internal and external networks.
--------------------------------------------------------------------------

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Name: Displayed mesh.gif
Displayed mesh.gif Type: GIF Image (image/gif)
Encoding: base64

Name: actual quad mesh.gif
actual quad mesh.gif Type: GIF Image (image/gif)
Encoding: base64

Name: meshbug.gid.zip
meshbug.gid.zip Type: Zip Compressed Data (application/x-zip-compressed)
Encoding: base64

--
--------------------------------------------------------------------------------
Miguel A. de Riera Pasenau miguel at cimne.upc.es http://gid.cimne.upc.es
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