Setting the ground properly in FPS Engine is essential to inform the Player about which surfaces are walkable and which are not. Fortunately, this process is quite straightforward.
On your surface, ensure it has got a Collider assigned.
It's advisable to avoid using Mesh Colliders whenever possible, as other collider options offer more precision. If you must use a Mesh Collider, Convex Colliders generally provide better results.
Attach the Ground Physics Material to the collider
Assign one of the provided Ground layers to this object (e.g., Ground, Mud, Grass, etc.).
This step ( Adding the layer ) is not necessary on 1.3 or above for the ground to be detected as walkable.
