Some details:
Class used by planes: fxPlane
Typemask used by planes: $TypeMasks::TerrainObjectType
Name of the plane built into the Slate: groundPlane
You can create, modify and remove ground planes like normal objects.
They have parameters such as "position", "rotation" and "scale".
To change the texture path or texture size, modify the topTexture, bottomTexture or loopsPerUnit and call the sendUpdate method on it.