These are all by nvseal
You could always ask him
A good place to start would be the file sharing section of the forum, I'm sure there's plenty of rocky surfaces in there you can take apart to find out how they work.
Overhangs are normally (but not exclusively) made as a displacement on a surface layer limited by altitude. Basically you define at what point vertically you want the overhang to start.
For decent rock texture its a much wider subject, there are so many differing types of rock in differing environments, take a look about the forum for tuts and examples. Try mixing (using the merge shader or stacking them as child layers of surface layers) different scale power fractals with slightly differing colours. Also try adding one or two Strata and out crop shaders.
Theres no quick fix scene creation in Terragen so the best way forward is lots of study and trial and error.
You could also try some of the
NWDA presets as well. Just be sure to read carefully their Licence agreement.
Richard
