Adidas 3D Printed Shoes, What Technology is it?

The key advantage of 3D printing is that in many cases designers can design and manufacture concepts what was impossible to manufacture conventionally. There is no way we could machine or even mold shoe-sole designed like this.
adidas Futurecraft 3D Printed shoes. 

The technology they are using is one of the most expensive one you can buy. it is called 

"Selective Laser Sintering" (SLS)

A thin layer of powder is spread over the platform of the machine and laser beam sinters the powder defusing it to solid. Sintering happens only in the area where we want to build our slice, controlled by slicer. The process of spreading the powder and sintering continues until the full model is built.

Here is a video to show you ...how

Refrences:
"adidas Futurecraft"
"3D Systems Respare"