I am now 3 weeks into my cast-restricted convalescence. And yes, it is as annoying, smelly and uncomfortable as everyone says. So when my accident occurred (a large dog was desperate to greet Luke and I was in its way), I toyed with getting our team to scan and 3D print a cast. The doctors were not keen, and since traditional casts are reliable, cheap and quick, I didn't argue.
If I had gone that route, what would have been involved? Well, as in the traditional approach, we would have waited a week for the swelling to go down. Then I would have had a 3D scan to get an exact image of my arm. The resulting file would then be modified to 3D print the lattice-like open "exo-skeleton" cast which would snap into place. Oh, to be able to scratch and shower undeterred! But I'm under no illusions; it could have been a pricey and time-consuming project - the design would have to withstand use and be printed in a non-toxic material, so while I was in a traditional cast 1 week after my fracture, it would likely have taken longer for a high-tech alternative.
But there are times when I'd give almost anything to scratch that itch.