[GiDlist] varying mesh quality
Posted: Thu Jul 07, 2011 4:48 pm
Hi GiD team
I have been repeatedly meshing a solid with normal tetrahedral elements with a fixed element size and the identical meshing parameters set in the utilities:meshing and get wildly different mesh quality (minimum dihedral angle) results for the mesh.
The results of 12 meshing runs gave me the following results for the minimum dihedral angle (smallest i.e. angle from) all in degrees.
1.35, 5.38, 1.31, 1.01, 3 wrong volumes, 13.7, 8.33, 3 wrong volumes, 6.78, 1 wrong volume, 7.98, 2.18
The largest angle was always the same at 70.5°.
Repeating the test with quadratic tetrahedral elements gave the following results
9.76, 1.31, 3.33, 3.9, gid encountered a problem & needs to close, 5.19, 2.83, 0.887, 1.73, 5.1, 1.36, 3.58
Again the largest angle was always the same at 70.5°.
Is this as expected?
Prior to this series of tests I had assumed when I got the error message "wrong volumes" that there was something wrong with my model or my selection of mesh size but now I know this is not the case. It appears that the meshing routine has an element of randomness and not wholly deterministic otherwise I would get the same mesh each and every time I pressed the mesh button?
If I want the best quality mesh is there any other way other than repeatedly meshing & inspecting the quality until I get one that I'm happy with? as this can be a highly time consuming activity.
GiD version 9.0.4 windowsXP 32bit.
Hoping you can help.
Regards
mark
Please be advised that this email may contain confidential
information. If you are not the intended recipient, please notify us
by email by replying to the sender and delete this message. The
sender disclaims that the content of this email constitutes an offer
to enter into, or the acceptance of, any agreement; provided that the
foregoing does not invalidate the binding effect of any digital or
other electronic reproduction of a manual signature that is included
in any attachment.
I have been repeatedly meshing a solid with normal tetrahedral elements with a fixed element size and the identical meshing parameters set in the utilities:meshing and get wildly different mesh quality (minimum dihedral angle) results for the mesh.
The results of 12 meshing runs gave me the following results for the minimum dihedral angle (smallest i.e. angle from) all in degrees.
1.35, 5.38, 1.31, 1.01, 3 wrong volumes, 13.7, 8.33, 3 wrong volumes, 6.78, 1 wrong volume, 7.98, 2.18
The largest angle was always the same at 70.5°.
Repeating the test with quadratic tetrahedral elements gave the following results
9.76, 1.31, 3.33, 3.9, gid encountered a problem & needs to close, 5.19, 2.83, 0.887, 1.73, 5.1, 1.36, 3.58
Again the largest angle was always the same at 70.5°.
Is this as expected?
Prior to this series of tests I had assumed when I got the error message "wrong volumes" that there was something wrong with my model or my selection of mesh size but now I know this is not the case. It appears that the meshing routine has an element of randomness and not wholly deterministic otherwise I would get the same mesh each and every time I pressed the mesh button?
If I want the best quality mesh is there any other way other than repeatedly meshing & inspecting the quality until I get one that I'm happy with? as this can be a highly time consuming activity.
GiD version 9.0.4 windowsXP 32bit.
Hoping you can help.
Regards
mark
Please be advised that this email may contain confidential
information. If you are not the intended recipient, please notify us
by email by replying to the sender and delete this message. The
sender disclaims that the content of this email constitutes an offer
to enter into, or the acceptance of, any agreement; provided that the
foregoing does not invalidate the binding effect of any digital or
other electronic reproduction of a manual signature that is included
in any attachment.