For example, you can print parts made of aluminum, stainless steel, or even titanium.
A lot is possible, but not everything.
"All" you need is a digital three-dimensional model of the part (STL file).
Some rework might be required, or it might even break.
But whatever, at least we tried.
And how expensive is expensive if you need a part for your favorite camera that was discontinued 50 years ago?
Or you want a simple lens hood that costs 300 or 500 bucks? - If ya can get one.
Or you want an eye correction device that was never manufactured?
. . . .
Sky pilot - how high can you fly?
. . .
I do IT with FreeCad.