Smoothing attempts to improve element quality by moving locations of nodes with respect to surrounding nodes and elements. The Low, Medium, or High option controls the number of smoothing iterations along with the threshold metric where the mesher will start smoothing.
Note:
In cases in which Smoothing is set to High and CutCell meshing is being used, additional smoothing of inflation layers occurs. This may slow down the prism generation process. Refer to The CutCell Meshing Workflow for additional details on Smoothing settings and their effects on CutCell meshing.