I'm sorry to be painful,
but I can't find the right solution.
as said, I'm a rookie in max, so the process I'm doing it might be wrong.
-in general, I made the basic assets and I applied the materials and UW mapping modifier to have the right look in viewport.
in particular. I selected the mesh, applied the material and the uw mapping modifier.
I adjusted the setting to have the right look.
I applied an edit poly modifier, made another selection and applied the material.
I put the second uw mapping modifier and adjusted the orientation.
it looks fine in viewport, I haven't collapsed anything and the handrail and steps are looking fine.
-now I have the repetitions problem:
either that the box mapping is on or off, it looks the same.
-if I put vray in cpu mode, box mapping seems to work, buuuuuuut, it mess up the uw map orientation,
after that, I can't find a way to go back.
I tried to put back gpu mode, on/off box mapping...but nothing.
Am I doing something wrong since start?
should I do something different?
I can't understand how to manage the mapping projection correctly