Selective Mask Sintering (SMS) is a digital, additive fabrication technique with great potential within Rapid Manufacturing. Three-dimensional parts are produced by selectively sintering or melting a thin layer of plastic powder, one layer on top of the other one, by exposure with IR-light through a digitally printed optical mask – i.e., a photomask – in the form of a toner image. The process thus transfers 2D images into 3D parts by melting each layer in a single exposure. This makes the SMS process significantly faster and more cost-effective than traditional laser sintering, which sinters each layer in a point-by-point fashion. The speed of the SMS process makes it suitable for use throughout the entire product life cycle for plastic parts; from the first prototypes, through production of parts, and finally to “Spare parts on demand”. Sintermask Technologies AB has developed the SMS-process, and has made the first SMS-machines commercially available during last year. The Selective Mask Sintering process and machine will be described in the following.