I'm having trouble meshing a volume using tetrehedral elements. I get the standard error:

ERROR: Tetrahedral meshing failed for volume volume.X This is usually caused by problems in the face meshes. Check the skewness of your face meshes and make sure the face mesh sizes are not too large in areas of small gaps.

In Gambit there are the following quality measures: - Aspect ratio - Diagonal ratio - Edge Ratio - Eqiangle Skew - Equisize Skew - Midangle Skew - Stretch - Taper - Warpage

My question is: which of the mesh quality paramters are the most important and are there any guidelines/heuristics for getting a volume to mesh other than common sense?

cheers, Novak.

I usually go by equiangle skew for everything, although equisize skew applies better to tri/tet meshes.

But the error message is right: you should try to get the best possible face mesh before trying to get a tet mesh. Use the 'move face nodes' feature to improve the meshes by hand.

Also, if you have large face mesh size differences, try to get rid of those. I recently had a single row of small boundary layer cells, and the tet mesh was very poor until I smoothed that layer away. Centroid smoothing can be helpful here.