You can't snap to the corners of the objects in RHINO

I couldn't objectsnap anything after I exported my model from revit to rhino since I'm trying to import it into dialux evo4, and then i realized everything was a mesh.....and so,

select all
"MESHTONURB"
enter

now i can export as .3ds which turns everything into a mesh again....so counter-intuitive....
and I'm going to try out new dialux evo4 for the first time.
Let see how it goes.