Rapid Prototyping (RP) is a term that covers a variety of processes which are aimed at quickly creating physical parts from 3D computer models using computer controlled machines. Virtually all RP processes are �additive�, that is to say the part is built up by adding, depositing, or solidifying material. This is the opposite strategy of a subtractive process such as machining, which creates objects by removing unwanted material from a large block in the form of chips. All current RP processes build up the object in a series of horizontal layers of varying thickness.
The word rapid in RP is a relative term, as most of these processes are actually relatively slow. The rapid actually refers to the reduced time from design to final part due to the elimination of extensive amounts of handwork (and setup/computer programming in the case of CNC machined parts) involved in making prototypes, as well as the ability to quickly iterate a design through various stages, resulting in drastically shorter times to production.
For pretty much all Rapid Prototyping processes, one needs to start with a closed, valid polysurface or “solid”
From that closed solid, a mesh representation of the model needs to be created/exported in the form of an .stl file
Polymer ink printer (Objet)
LOM (Laminated Object Manufacturing)