I'm trying to make a shooter game , so I use the terrain map then I put some trees and rocks , but the problem that I across the trees .
is there away to stop the player when it collide with the trees
Yea, that little check box doesn't do anything I've found...
What you're going to have to do is get the prefab of the tree, make a duplicate, then add a collider to it, then use THAT model for the tree...
Setting up Tree Collisions
If you'd like your trees to make use
of colliders, it's very easy. When
you've imported your Tree asset file,
all you need to do is instantiate it
in the Scene View, add a Capsule
Collider and tweak it, and make the
GameObject into a new Prefab. Then
when you're adding trees to your
Terrain, you add the tree Prefab with
the Capsule Collider attached. You can
only use Capsule Colliders when adding
collisions with trees.
I create a separate scene for doing this. That is, create a new scene and place all of your trees, bushes, etc. in there (evenly spaced) so you can work on them individually. As long as they are Prefabs then anything you do to them and apply will be available throughout your project.
Doing this de-clutters you game scene and gives you an uncluttered scene (that will not be part of the game build) where you can tweak and adjust your terrain elements. I have additional scenes for building, props, characters, etc.