Build and walk upon structure (wall) ?

[Snowstorm]

Needs some tips/help?

I'm gonna have walls (custom models) they should be walkable and buildable upon, but how can I make my walls so I can build structures on top of them.
I know I could use terrain->Dalaran->Cliff, but the walls would also be buildable by a unit and custom, so that doesn´t work..

This is what I want:

 

[Binsu]

I guess Invisble Platform would do the trick here. Try using that pathing and some tutorial to go with it: http://www.hiveworkshop.com/forums/general-mapping-tutorials-278/pathing-everything-about-154558/

 

[Heinvers]

Agree with Hell Master. If u plan doodad bridges instead of destructible ones then yes, the invisible platforms are the best choice. Plus that u can make custom ones with different sizes too. Have a good day!