How do Obito use kamui to move from one place to another? We have already seen that inside the kamui space, there are big square stepping stones and nothing else. So, how can he move absorbed himself into the kamui space, and materialize again in different place in the real world?
Obito doesn't need to move inside Kamui space to move in the "real" dimension. If he wishes to move in his "current" dimension (Kamui or real) then there are two ways: either he physically moves inside that dimension or he goes into the other dimension, and while coming back, he returns at a different place.
However, while using his ability to let things pass through him, the things stay in the same place in Kamui space and return to the same place in the real dimension as well (cause it'd hurt terribly if your stomach was to be taken out and placed over your head).