Revit DataSmith Import - Mesh Collision Setup

I have a simple house and topography that I have exported from Revit 2019 using the DataSmith plugin. I can import the house and ground into Unreal Engine 4.21 just fine.

The problem I am having is that when I run a simulation there is only one mesh, out of 290+, that has any collision to it. The simulation passes right through everything else. I have tried and tried to see what makes that one mesh different than the others but all the properties seem to be the same.

How do I make the imported meshes, walls, floors, stairs, etc., have collision so that there isn’t any pass through?

Any insights would be most appreciated.