This image shows tfBlur activated on the right-hand terrain.
This increases the radius of the strength of the Blur filter, smoothening out transitions in the terrain.
Larger values will take longer to calculate.
These three terrains have Mode set to Box, with an increasing Radius value, driving an increasing amount of blurring.
There are five different Mode settings of tfBlur: Box (the default), Gauss, Median, Gauss, fixed 3x3 and Gauss, fixed 5x5.
Both terrains in this image have a Radius of 3. The left-hand terrain has a Mode setting of Box, whereas the Gauss setting on the right gives an increase in blur quality, while preserving finer details.
This is the default; the fastest Mode setting.
A slower Mode setting, but Gauss is much better quality and will give smoother results.