Laser sintering at 200x magnification.
SLS (Selective Laser Sintering) creates a 3D model by bonding tiny plastic particles together by melting them with a laser. As you can see in these 200x videos through a microscope, the 3D printed structure is still, essentially, particles.
The video above shows the surface of a nylon laser sintered part with all of its microscopic imperfections, and the video below after the jump shows nylon powder next to a single human hair for scale.
The videos come from Brandon’s Twisty Puzzle Channel on YouTube.