Noctua is awesome in a lot of ways, one of them is offering full CAD models: https://www.noctua.at/en/3d-cad-models

One of the first things mentioned on that page is:

> To protect our intellectual property, certain features – such as fan impeller geometries – have been slightly modified while remaining visually very close to the actual product.

So you do have to 3d scan them yourself if you're trying to print a copy.