Greetings,
I reproduced a carburetor heat control choke plate in 3D for a 1927 Buick. The object will be 3D printed.
3D printing and designing is my hobby for more than 6 years now and I had many functional designs on thingiverse.
I'm able to reproduce various missing or broken parts. It always helps if there is an example part which can be measured by caliper to be copied into 3D.
Personally I like to copy by caliper and ruler. For smaller parts I can use a 3D scanner.
Reproduction can also be achieved from a minimum of 3 photo's (top view, front view, side view,) but the more views the better plus general size of object i.e. HxWxDepth.
Sometimes reverse engineering can produce parts too
Let me know if I can be of any help.
Regards, Matt