Working at manvsmachine.co.uk/ I had the chance to discover a new way to create this kind of landscapes just with a plane and the displacer effect.
All you have to do is to create a plane object, then add a displacer effector as a child and play with the layers on the shader parameter. It's worth playing with so many layers to reach complex shapes (some of my shapes have a plain effector as well).
In this project I created a realistic AI Vision system in Houdini.
The agent can process it's own perspective view and detect obstacles in real time.
Also he can can detect obstacle's color and take it to apply it's own body !