wall lines showing up on 3D view

[Bemerjc]

I am designing a multilevel home that has a mezanine level. The problem I am having is that when I look at the house in 3D view I can see all the break lines where interior wall meet the exterior walls. I have made sure that each level is align with the above/ below but I can still see where each interior wall meets an exterior wall. The breaks look like white trim boards in the siding. How can I make these disappear so I just see the siding?? I would post the
3D view of it but I don't know how to do it.