## Description

The controls in the *Smoothing* frame allow you to set a desired quality threshold,
specify which cells are selected for smoothing, and improve the stability of the Weighted
Condition Number smoothing routine.

The Smoothing frame provides controls for the Weighted Condition Number smoothing routine.

The *Convergence Cost Threshold* allows you to specify a maximum threshold
value for the minimum quality cost function and stops the smoothing routine prior to reaching
the number of iterations specified on the *Solve Tab* if this
maximum is achieved. The * Convergence Cost Threshold* varies from 0.0 to 1.0 and has a
default value of 0.95.

**Note:** The *Cost Angle* is an alternate form of the
*Maximum
Included Angle*. The *Cost Angle* computes a face normal
for each corner of a quadrilateral cell face whereas the examine metric uses a single face
normal computed from the two quadrilateral face diagonals. The *Cost Angle* takes
longer to compute, but is more accurate because it accounts for quadrilateral warpage.
This ensures all cells with large maximum included angles are smoothed.

The *Cost Angle Threshold* sets the angle to determine which cells in the mesh
receive smoothing. *Cost Angle Threshold* varies from 0.0 to 180.0 and has a default value of
175.0. A value of 0.0 enables a special mode that uses the ideal isotropic tetrahedral shape as
the target for each cell.

**Tip:** Using a value of 0.0 for *Cost Angle Threshold* enables a
special smoothing mode that uses the ideal isotropic tetrahedral shape as the target for
each cell. This is extremely useful for smoothing blocks that contain only isotropic tetrahedra,
but is not recommended for blocks containing all cell types, T-Rex layers, or voxels.

The *Relaxation Factor* is used to limit grid point movement during smoothing
to improve stability. *Relaxation Factor* varies from 0.0 to 0.5 and has a default value
of 0.1.