This paper shows the need to consider the Rapid Prototyping (RP) of non-assembly planar mechanisms as a case of Design for Manufacturing (DFM). The influence of the support material present in the clearances is discussed from a kinematic perspective. Geometric features are introduced into the design of the parts so that the kinematic performance is independent of the presence or absence of the support material. Kinematic requirement in combination with the process limitations of RP, results in new designs of the mechanism parts. The advantages and challenges in non-assembly RP of mechanisms compared to assembly after part fabrication (through RP) are discussed through a case study. A functional application example of immobilizing a four-bar mechanism with a single stopper is demonstrated through fabricated RP model.