I am finishing recording series tutorials about terrains, trying to cover all of it. Here list of tutorials, please let me know if you want any thing else:
Terrain editor overview
Standard terrains part 1 (overview, options, seed, filters) [23:44]
Standard terrains part 2 (fractal options, 3d tool) [21:37]
Standard terrains part 3 (functions, altatude options) [12:58]
Sphere terrains overview [4:54]
Infinity terrains overview [5:13]
Precidural terrains overview [12:55]
Precidural terrains, functions part 1 (standart fractal ) [28:23]
Precidural terrains, functions part 2 ( terrain fractal ) [18:54]
Precidural terrains, functions part 3 ( fractal nodes, mixing terrains, external dependecy) [10:34]
Terrains, effects tab [16:38]
Terrains, 3d sculpting, techics and tips [32:24]
Material painting with terrain editor[18:18]
Infinity terrain, advanced options [29:00]
Spherecal terrains, advanced creations (project) [16:20]
Creating rocks [8:14]
Terrains and material displacement [11:44]
Ecosystem interaction with terrains shapes(rivers) part one [18:02]
Ecosystem interaction with terrains shapes( effects and layers) part two [16:02]
Hypertexture terrains [12:55]
Terrain depended materials [22:!5]
Creating materials [31:22]
Material distribution overview [26:21]
strata filter part one [32:21]
strata filter part two [24:12]
Icebergs [22:01]
USGS (DEM) terrains [11:38]
Terrains advanced function editor [20:16]
Put all togheter [27:14]

