How do I make my model's direction Compatible with terrain? (there is a picture to explain)

I’m using third person character from Standard assets by replacing Ethan’s body with my model … I know this is sounds newbie, but this is the only way I know to make third person character, My model is not a human he has four legs, and this is why he didn’t compatible with terrain Heights! he walking straight on every different height…

I checked all the colliders, adding rigid bodies + locking directions… all that attempts isn’t working because I face new issues like jumping suddenly out of the map…etc… so Help me this is my last hope!

look at that example:

Note: My model is not a car I’m using car as an example…

I think you need to refer this link

hope you are looking for it