The paper gives a state-of-the-art overview of so called rapid prototyping techniques, like stereolithography, selective laser sintering, ballistic particle manufacturing and others. These are new manufacturing techniques in which the part is produced by gradually growing material to the required shape. A tentative classification and nomenclature is proposed. It is shown that those new processes are ideally suited for CIM. The paper tries to compare the different processes and discuss their application and performances.