Adjust Y-axis

I need to tranform an object to a certain place witch depend on a player. I can calculate x and z axis but not y. The problem is that terrain is not flat and i need that boject to be grounded.

Assuming you are talking about a Terrain, you can use Terrain.SampleHeight(). There is a sample script at the link. If your pivot of your character is not at the feet, you will have to add a constant to the value returned.

An alternate solution (that also works for non-Terrain objects) is to raycast down and use the hit point to adjust the ‘y’ position.