Some German tank photos I've seen show tanks covered with branches and foliage for added camo. They are secured with ropes tied through metal loops welded to the hull. Are these wire loops attached in the factory or are they field mods by the crews?

Thanks!

You can see almost on every tank that loops. Most of them are attached at fabrics, but there are more of them welded to the hull at the field, too. I suggest you to study the reference photos.