I don't know about you, but I've never seen a store that has merchandise on only one side of the aisle. Talk about wasted space! Therefore I had to go to the tedious (yet fun) chore of creating a back side to each shelf. If you go back to Slide 5 of this presentation, you will notice that it would be impossible to photograph the shelf from behind because the wall is there. In order to create the back sides, I had to do some serious manipulation and creation, using as much real data as possible so the back side wouldn't look synthetic next to the photographed side.
The first step to success in this illusion is to mirror the perpendicular faces - in other words, copy all the sides that face the viewer on the end of the shelf. This would include the ends of each shelf and some of the canvas sides if desired.
The faces are selected out using the polygon selection (mask) tool, copied to separate layers, mirrored horizontally and positioned behind our new wall thickness plate.