This article talks about how 3D printing is being used to create what are called "metamolds": hard, 3D printed molds that are used to create softer, silicone molds. When the silicone molds wear out, new ones can be made with the rigid metamolds.
Software is used to help create the metamolds as well as calculating the best places to make cuts on the mold to separate it from the object inside the mold.
This could have great possibilities for creating resin objects for model railroading such as vehicles. It shows that 3D printing is even impacting other methods of creating 3D objects!