3D printing doesn’t always start with a human designer or creator. There are wide variety of 3D scanners that can be used in the 3D printing process.
A 3D scanner is a device that analyzes a real-world object to collect data on its shape and possibly its appearance. The resulting data can then be used to construct 3D models.
3D scanning is no replacement for a human designer, but can offer a good start creating a 3D representation.
Each 3D scanner has its benefits and limitations, and resulting data will always need much work before it can be used in 3D printing.
3D scanners can offer a lot of benefit in rapid prototyping, and reverse engineering of existing objects.
Just like 3D printers you will find a wide range of 3D scanners, in both functionality and price.
You can also find innovative hobbyists employing tools like the Xbox Kinect for generating 3D scans.
3D Scanners are just the one possible link in an evolving 3D print and manufacturing supply chain.