Another Wilbur Question

[waldronate]

OK, try this (attachment 1, 4):

Generate a basic terrain by Filter>>Noise>>Fractal Noise with amplitude 100. This way the terrain goes from 0 to 100.
Draw your cliff edge selection.
Filter>>Fill>>Mound with minimum height of 0, maximum height of 2500, and Operation of Add.
Filter>>Height Clip with min of -1 and max of 150. This change will give you steep slopes from the terrain up to 150.
Select>>From Terrain with minimum 150 and maximum 1000 to pick just the upper plateau.
Select>>Deselect to hide the selection.
Filter>>Erosion>>Precipiton-Based with the default parameters to round out the bottom edges of the cliff. Do this again as much as desired.
Select>>Reselect to get your flat upper area selection back.
Filter>>Fill>Set Value with a value of 150 to return the upper area to its flat state.
If desired, Filter>>Noise>>Fractal Noise with Operation Add to get a little interest in the upper part.

Alternatively (attachment 3):

Start with a blank terrain.
Draw your desired edge.
Filter>>Fill>>Mound with Minimum 0, Maximum 10000, click the Edit Profile button, enter 2 for non-linearity, click apply, then OK and OK again to generate an exponential blend between the low and high portion.
Filter>>Height Clip with Min=0, Max=100
Select>>Deselect to hide the selection.
Filter>>Noise>>Fractal Noise with Operation=Add and Amplitude=100.

In the last image (attachment 2) I downloaded a simple maze from http://www.billsgames.com/mazegenerator/ and applied the second technique to it followed by some cheight clipping.