Rapid prototyping refers to a host of related technologies that are used to fabricate physical objects directly from CAD data sources. These unique methods add and bond materials in layers to form objects and offer advantages in many applications compared to classical subtractive fabrication methods such as turning or milling. Objects can be formed with any geometric intricacy or complexity without the need for elaborate machine setup or final assembly. Objects can be made from multiple materials, or as composites, or materials can even be varied in a controlled fashion at any location in an object. These capabilities have resulted in rapid prototyping's wide use as a way to reduce time to market in manufacturing. Today's systems are extensively used by engineers to better understand and communicate their product designs as well as to make rapid tooling to manufacture those products.
Rapid prototyping processes include stereolithography (SLA), selective laser sintering (SLS), fused deposition modeling (FDM), 3-dimensional printing (3DP), and laminated object manufacturing (LOM).