How can I use terrainData for navmesh ? is it possible ? or what is it (check attachment)?
I’m assuming that it’s just a normal Unity terrain. So if you’re using a terrain, you drag and drop it into that slot, and it will be used to generate the navmesh (instead of the normal calculation, which is probably less accurate).
It’s used for more accurate height lookup when placing agents and for height value (y-coordinate) in queries like navmesh raycast. It’s enabled by the “Height Mesh” flag on bake settings - if terrain is present the navmesh stores a reference to the terrain - which is what you see in attached screenshot.
For more info on heightmesh : http://docs.unity3d.com/Manual/nav-HeightMesh.html