Read: A History of 3D Printing
Please take time to read through the article which is a comprehensive beginner guide to 3D printing. It is a perfect on-ramp to the topic and covers 3D printing basics, history, technology, processes, materials, global effects, benefits and value and applications of 3D printing.
You will find out that it all started over 40 years ago in the early 1980s so it is not a new idea. However, it is now a mainstream technology being used in every industrial sector, the arts and beyond.