Abstract: The installation is constituted by means of the functional combination of a water curtain generator or orientable arc-generator and of an observation platform, said water curtain generator (4) having a structure that is based on a plurality of uniformly distributed sprayers with an ascending water projection, consequently obtaining a homogeneous water curtain; the observation platform consists of a circular pool (3) with an observation-ascension ramp (1) that surrounds it, the height that this ramp must reach at each point, shall depend on the geographic latitude; the observer shall be situated backwards to the Sun on the observation platform, the arc-generator perpendicular to the rays of the Sun at a set distance facing the observer, with which the primary rainbow (5) generated by the incidence of the Solar rays on the water drops, will be visualised.

Abstract: A three-dimensional object is modelled by solidifying superposed layers in such a manner that on an already solidified layer a following layer of initially liquid or powdery material is solidified by light action or the like in correspondence with the form of the object.