Hi,im pretty new in tiled and i want to create a terrain that looks like this:
but it end up looks like this:
It works well in the center but the problem is the corner of the tile,so how to create a terrain that looks like in my first picture?,i don’t really understand about how terrain works ^^a since it is my first time using tile editor,any help will be very appreciate thank you for your time =D
Tiled does not currently support RPG Maker style terrains. This is because to make those work, RPG Maker implements a special algorithm where the tiles are cut in pieces smaller than the tile grid and are then recombined to make all possible configurations.
See the following issue on GitHub for more details:
https://github.com/bjorn/tiled/issues/1022
If you follow the Using The Terrain Tool documentation, you will see that the terrain system in Tiled works differently.
Sorry for a late reply and thank you for the explanation =D even it cannot do the autotile like RM but it is still a nice editor keep up the good work ^^
Any news? 
See the linked GitHub issue for the latest discussions about this feature. It remains to be implemented.
For Tiled 1.3 I plan to add scripting. Maybe this RPG Maker terrain logic would be a nice thing to try implementing as a scripted brush.