Hi, I want to create a solar chimney that is attached to a room and sharing one wall with that room. My problem is; wall of the chimney which is shared with attached room always takes wall of the room's construction settings. For example if I set 1cm wood plate for chimney wall construction setting room's shared wall also tuns into 1 cm wood wall. I tried to create a sub-surface for chimney wall and attend wall properities like that but it also didnt work. It acts like I didnt set a sub-surface. How can I make them act as different walls?