I'm not sure if what I've done qualifies exactly. I just call it backdrop, and it is a very long, continuous thing on my layout. The layout is comprised of two sections that run along the north and south walls, and three peninsulas out into the middle of the room. Although they aren't complete, you can get the idea from the photos. There will be photos and building flats applied to them eventually.
This section in aisle two is getting close to being done. A few more building flats. some trees and clouds should wrap it up.
I put a couple flats together to conceal this opening where the track goes through.
Here's an overview of aisle two. The entire room used to be wide open. On the right is the partition with aisle one. On the left, the partition with aisle three, and the center of the room. Each deck has long continuous scenes.
This scene in aisle one will get a painted cutout made of pink foam sheet, mounted to the sky. I'll be using similar treatments along most of the lower deck on aisle two.
Here's a bit of an overview of aisle one. On the right is the south wall, and on the left is the partition between two and three. The upper will be mostly photos of the real structures in the area.
You can't see much of the backdrop anymore, because this scene is nearly complete. This is on the lower deck in aisle three.
Here's an overview of aisle three.
The scenery will wrap right around the end of peninsula three, hiding the helix behind it.
Over in aisle four the Hiawatha Milling District runs nearly 40' through a "canyon" of elevators and mills.