Model collision?

Recently i made a model of a stone wall, since all the warcraft wall models are pretty lame. However when i use my wall model in the game its like it has no collision. What i meen is that u can walk right through the thing. No boundrys. Any help here on how to make it solid so u cant walk through it?
also i have already checked by default its not walkable in object editor.

Well, the model doesn't have anything to do with pathing. Structures and doodads have special pathing maps that determine how do they collide. You must select a map that corresponds with the shape of the wall.