Orthogonal Quality

The range for orthogonal quality is 0-1, where a value of 0 is worst and a value of 1 is best.

The orthogonal quality for cells is computed using the face normal vector, the vector from the cell centroid to the centroid of each of the adjacent cells, and the vector from the cell centroid to each of the faces.

Skewness

Skewness is one of the primary quality measures for a mesh. Skewness determines how close to ideal
(i.e., equilateral or equiangular) a face or cell is.

According to the definition of skewness, a value of 0 indicates an equilateral cell (best) and a value of
1 indicates a completely degenerate cell (worst). Degenerate cells (slivers) are characterized by nodes
that are nearly coplanar (colinear in 2D).
Highly skewed faces and cells are unacceptable because the equations being solved assume that the
cells are relatively equilateral/equiangular.

Maximum Corner Angle

Maximum corner angle is computed and tested for all except Emag or FLOTRAN elements. Some in the finite element community have reported that large angles (approaching 180°) degrade element performance, while small angles don't.

Parallel Deviation