I had been out of 40k since 3rd (sold armies, etc), then some buddies got back into it 10+ years ago. Not having the funds at the time, I built an army from shrink-film.
I had to print out images to trace and do the maths so the final result was passable. This is why I made a conversion ruler (original length in blue, final size in red).
I never got around to vehicles or walkers, but I was designing some slot-together bits.
We used to do this with Warhammer Fantasy Battles in college!
We had access to a laminator so the paper was cut out to the regiment size and we could use dry-erase markers.