mecanim animation problem with terrain collision

Hi I have a question about mecanim. The character seems to run into the hills of the terrain as if there was no collision detection, but somehow the character does not sink into the ground, meaning that there is collision detection on the horizontal plane.

I wonder what is going wrong here? thanks!

There’s not necessarily any “collision” with the ground either. It just sounds like you’re not changing the y value of your character at all, and it’s default position just happens to be placed on ground level.