<human>:  How does a 3D printer work?
<bot>: A 3D printer works by taking a 3D model, which is created on a computer, and then creates a physical object from it by laying down successive layers of material until the complete object is formed. The 3D printer utilizes a variety of materials, including plastics and resins, to create the object. Each layer is thinly sliced from the 3D model, and then the 3D printer's build platform or build tray moves down by a fraction of a millimeter. The 3D printer then deposits a thin layer of material on the build tray, melting and hardening it in the desired shape as designed in the 3D model. This process is repeated until the object is complete.