Directional Smoothing

The Directional smooth checkbox is just below regular smoothing.

Directional smoothing produces a stronger smoothing effect in one direction and a weaker effect in the perpendicular direction.

In the provided text box, enter the primary smoothing direction.

Set the influence radius along the primary direction with Smoothing strength in the primary direction.

Use Smoothing strength in the secondary direction to control the influence radius at a 90 degree angle to the primary direction.