How to disable Colison check to build Walls into "MapStucture"

Hy i need to find a way that i can build my Walls into the Map Structure. I figuered out the “High colision” but any time the Wall is hit the Map Structure with his full box its disallow placement.

what settings i have to change to build without this box check and HOW. I tryed anything in the Placement Settings but nothing works.


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