Looking for unubtanium part ideas

Okay. I am openly and totally admitting that I am new to this. I don't totally, nor quite understand this technic. Can you explain it better than wapitikia (sp )? I have some hard to/ can't find / they don't reproduce parts that I'm looking for and many follow me in the same pursuit. So I can bring you more. Thanks
Short answer...

I take a part, typically small, and measure it up with calipers.

From there I draw it in 3D CAD.

I take the CAD file and print it on my 3D printer (mind is a UV cured resin printer)

Then compare the printed part to the OEM part.

Once I am happy with the part I can send the file to a 3D printer who can print it in metals.

A lot of 3D printing that many see is FSM A filiment of plastic is heated to melting and applied layer by layer in a pattern to build the part. The resin printing does similar but UV light is passed through a mask the shape of the particular layer and in only the places that are not masked the light gets through and cures the resin.

This happens over and over till the part is made. This process makes a more smooth and uniform part, vs FDM which looks more like a log house.