Going from patent and model to STL file

So I'm a beekeeper and we have to continuously adapt our tools to change and predators. For the fight against asian hornets, the 3D community has been really helpfull and most of the stuff can be printed at home with a small 3D printer.

However, for other stuff, such as mechanical treatments against Varroa (a nasty parasite responsible for a lot of diseases and death in bee populations), usually you can open your wallet and pay an excessive amount. Because the alternative is death and being a menace for other beekeepers and solitary bees.

There is for exemple a little cage that is usually used to rear queens. One fellow misprinted it, and has noticed that it blocks the development of the laid eggs into larvae (he left 7mm oh developpment height instead of 8mm). This doesn't harm the queen or colony, and blocks reproduction of the parasites. After 28 days, there are no more larvae in the hive, all the parasites are exposed, and we can treat once the population kill off the nasty buggers. It is also an efficient way to sample parasites for the development of varroa-resistant lineages of bees (because we need to infest those with the parasite and then check if it is resistant or not).

Of course, that little cage that was misprinted is now under a patent, and is sold way to expensively for what it is (10 bucks, it's not food-grade certified and the lock breaks way to easily). I do not mind paying for somebody's work, and fair is fair, but slapping a patent on a item that exists since decades because you slightly modified it and selling it expensively while manufacturing it on the other side of the world is a little too much for my liking. I know it's how the world works, but that doesn't mean that I have to roll over.

Anyway, I've got some bought cages, and the patent. How would I go to make a STL file to print it afterwards? It's made of a box with the hexagonal frames and some dead space for the queen, a lid to allow workers to move and a little lock. 3D Scanner? Drawing it from zero on FreeCAD with the patent and the cage next to me? Praying to Chtuluh to send me magically the file with a carrier pigeon? Or am I forced to go looking at an far-eastern webshop with a bad carbon footprint, where they sell it for 3 bucks a piece?