The present invention relates to a system and method of transforming an inconsistent 3D (three-dimensional) model of one or more 3D objects into a valid printable 3D model, said method comprising: (a) receiving an input model file and/or receiving modeler data, giving rise to an input 3D model having one or more parts; (b) analyzing said input 3D model and removing its one or more inconsistencies; (c) thickening the one or more parts of said 3D model, while preserving their functionality; and (d) unifying the union of interior volumes of said one or more parts, thereby removing self intersections and/or intersections between the two or more parts, giving rise to a valid printable 3D model.