In this paper we describe a geometric software package which serves as a data front-end for rapid prototyping systems. This package can be customized for every layered-manufacturing technique. We survey the full path of data in the system, starting as data files originated by external tools, in most cases CAD systems, going through some repairing operations, then editing a job composed of several objects, and finally processing the job for actual production. Keywords: geometric software, rapid prototyping, layered manufacturing, polyhedra. 1 Introduction Layered manufacturing has become during the last decade the major method for Rapid Prototyping (RP) of models. Physical models are needed in almost every industry for design verification, simulation, integration of complex systems, etc. RP has also applications in medicine (e.g., in surgery planning), in chemistry (e.g., for verifying docking sites of macromolecules), in architecture, civil engineering, and so on. RP has emerged as a...