The effect is to have different ‘looks’ within the same terrain - for example, adding noise only to the hills, while keeping the valleys smooth.
Masks by altitude level. You can constrain the operator to certain altitude levels of the underlying terrain.
Enables the Altitude mask.
Below the level set, the operator will be masked out.
With the Min value at 75cm, everything lower than this is being masked.
Softens the minimum, to make the contrast less severe.
In this image the Min value is 35cm, but the Min Soften setting of 30% in the right-hand terrain is minimizing the contrast between the masked and unmasked areas.
Above this level, the operator will be masked out.