SilverKey said:
The compositing job done on McGregor is quite bad. They even used footage of McGregor that was shot (but cut) from the Mustafar duel with Anakin and it shows. The eyeline between him and Grievous are way off too. None of the elements in the scene really match.

Also, the whole background doesn't make any sense. When Obi-Wan looks down on the Separatist meeting, Grievous we see that the floor is flat. But when Grievous pushes Obi-Wan back, they are walking on beams. And where is did that thing Obi-Wan dropped on Grievous' guards, and their bodies, go?

Well i return to this because i checked the scenes.

It seems that editing cut several footage that shows grievous push obi further back or is just bad edit.

You can see clearly that there are "beams"(?) in very back of the room. But you are right about the background sometimes cause a big mess. Yes the box that fell on magna guards disappears. For one moment i thought that they we fighting in different levels of this location because it looks different.

-Angel