A simple button goes through a long process before being attached to a coat and, having recently made set of 3rd New York buttons for a new friend, I captured the process in a series of pictures that may be of some interest.
The first stage (no photos because it was done a long time ago) is the research which is sometimes easy but more often painstaking. Then the prototype is constructed and often destructed several times because it isn’t right. From that a rubber mould is made and the casting can begin as shown below.
As you can see I have to fit my casting in between mealtimes as the kitchen doubles up as a workshop! (sorry Jan)