TerrainHeight returns a float between 0 and 1. A terrain is 1 unit high by default.
So if you've scaled the terrain, 'Y# = (TerrainHeight(Terrain,X,Z) * ScaleFactor) + EntityY(Terrain)' will give you the global Y position.
So if you've scaled the terrain, 'Y# = (TerrainHeight(Terrain,X,Z) * ScaleFactor) + EntityY(Terrain)' will give you the global Y position.