Smooth

The Smooth menu can be found with the [Smooth...] button in the main General Tool menu. This operation smooths bumps and corners in the selected area.

Filter

With the [Filter] option, you can choose what blocks to be affected by the operation's adjustments. You can choose to only affect a certain block ([Normal]) or to affect all blocks except a certain block ([Exclude]). Once enabled, it can be disabled by using the button again.

Settings

The [Settings...] button opens another menu:

The Edge detection limit option controls the maximum blocks along a corner that it searches to find out how big the corner is.

The Intensity option controls how aggressively corners are rounded, with a value of 1-5.

The direction options toggle which directions it smooths relative to. For example, if you were to only have [Up] selected, it would only smooth out the sides of vertical upwards-facing bumps. The [Down] direction is disabled by default, as it can cause some unwanted behavior.