Originally Posted by Human Rasengan
With the relationship between Tobi and Kakashi's jutsu I wonder if Tobi notices when Kakashi uses kamui and if pain's nail and Deidara's arm are in Tobi's box zone.
From what I remember, kakashi transported diedara and his arm in to another location where diedara already retrieved it. From the new chapter, I think kakashi understands his kamui technique a bit more and how it works. Probably, when he uses his kamui, he transports the object through a dimension with no time/space like a void, then the object instantly reappears in another location from that void as the void has no time flow.
So I would say kakashi transported the rasengan to the void dimension and back to the same space as it seems like he has more control of it.