I have some footage filmed with green screen. I want to take out the greenscreen and replace with a poser background..so some of the action takes place in a ring..I have no problems with a straight on shot where the green screen is directly behind the actors but how do you do it when they run ropes or go into the corner? I have green screen on three sides but how do you "stretch" the background and wouldnt you need the same bland background and anybody got any idea on what poser products I could use for said background...it has a horror feel to it. Thank you.