How to unwrap multiple planes and have them exactly overlap?

Question

I'm currently modeling a stadium for a game and am trying to find a quick way to get all the rows of seating to share a UV image. Each plane is the same height but differs in length, but I can just have the UV image repeat itself for longer planes.

Here you can see how I'd like each plane to land on the UV map, obviously differing in length.

I've just did a smart unwrap, but it lays them all out without overlapping. Is there a way to have them all overlap in the UV without having to painstakingly move each one by hand into the correct area? Even if they were all along the same X plane, not overlapping, that would work fine. Just now, they're stacked with spacing in between them which throws off most of the rows of seats, making them cut in half or floating and other issues.

Any help is greatly appreciated!

Answer 1

I found a work around. If I unwrapped in as a Smart UV Project, it placed all the unwrapped planes tightly together, as in no space between them. So, if I aligned one of the planes to the corresponding UV image, the rest of them repeated correctly.

Answer 2

You can do this by using magic UV addon.

After enable addon go to edit mode, select one plane, unwrap it how you need, than press U -> copy/paste UV -> Copy UV

Next select all planes with same size and U -> copy/paste UV -> Paste UV

In this case you need to repeat this operation as many times as you have variations in length.

UPD Found this addon: Textools that can easily achieve your task: