Use PhysX Clothing lost something

I want to use PhysX Clothing in some UE Project.I face some problems as followed:
1.I import the fbx,it’s OK.but when I add the .apx file,I lost the things which isn’t cloth.Why?

(.fbx you can see there is one sphere.)
but after use .apx file,you can see the sphere is missed


2.How can I make the apex Clothing things collide the ground or others things like the stairs?

I made a mistake in material import.How can i close this?