If you have a curve,I duplicate real life objects all the time to print them as replacement parts, I used to find this difficult but if you think about how a curve is made up, it's not very difficult, there's a line leading up to it and a line exiting it, if you know the difference and have the lines placed where they belong, then just add in the curve. That usually does it for me, sometimes figuring out how many segments in the circle can be tricky, but generally you can tell if it's a very smooth (high segment) or kind of blocky (low segments).That's usually how I do it and that works for me, hopefully that makes some sense.