I do both, and the they both, use g-code that is generated by some other tool. V-Carve, Fusion, Bob-cad etc for CNC, or various "slicers" for 3D printing. Slicing takes your 3D model and cuts it into defined layers, usually around 0.2mm, sometimes as low as .05mm. The difference being one os subtractive and the other additive. In the most basic sense, it's the exact opposite.
The biggest problem with FDM style 3D printing are the artifacts from the layering. If you can get your part printed using one of the "resin" printers, you're going to have much better results. Even then, since you are limited to materials, it's almost best to get a resin print, then use it to make a mold for injection molding.
in the end, it's not so much what you can do, but rather what your expectations are. PLA for instance, is REALLY easy to print, but on a hot day, you'll know why in a hurry.
