Ok, so I made a blend, put some perspective on it and then went through the process of selecting each circle and making each into a semi-circle (as discussed here http://www.talkgraphics.com/showthre...582#post518582 )

This is just to begin, to see if I can work out how to do. I tried selecting all, convert to editable shapes, but the nodes don't show for each one, so I realised 'you must' do each one individually (don't know of a quicker/easier way).

End result was a vary basic arched corridor (looks more like one of those long greenhouses for mass production lol) - so initial success

Then I wondered if I could alter the perspective, so select the smallest arch, ctrl alt and you just move the one arch. So, managing to select all, the ctrl alt trick does move them all, but not in the same manner which I am guessing is due to making them all editable shapes - the arches become in effect a glued rigid structure.

So the key to this is making sure you position your concentric circles perspective correctly before converting and cutting them up!

Another plus for me in doing this exercise, is that I am beginning to understand perspective a little better, and when I see 'blind spots' mentioned, I'm starting to grasp what you all mean