3D printing apparatus of the bottom-up photo-curing type, comprising at least one source of a radiation capable of obtaining the photo-curing of a photo-curing liquid material, above which a tank is arranged containing said photo-curing liquid material and inside which at least one extraction plate is immersed, which is provided with moving means with alternating rectilinear motion, along a direction perpendicular to the bottom of said tank from a position at a distance from the bottom of said tank equal to the thickness of a layer obtainable by photo-curing of said photo-curing liquid material, the bottom of said tank being constituted by an elastic membrane of an anti-adherent material which is transparent to the radiation of said light source , said tank being placed on a support plate , whereby said support plate comprises, in the portion below the bottom of the tank , a mobile support element, configured to move by translating and/or rotating in the plane in which it is positioned, which, alternately - is made entirely of the same material transparent to the radiation utilized for the photo-curing, with one or more perforated or lowered portions with respect to its upper surface, of a size equal to the printing area size, and between said at least one source of a radiation suitable for obtaining photo-curing of the liquid photo-curing material and said mobile support element a system of lenses with different refractive index is interposed, or - alternates, at regular intervals, a portion of a material transparent to the radiation used for the photo-curing, of a size equal to the size of the print area, and a perforated portion or lowered with respect to its upper surface, of a size equal to the size of the printing area, the support element being able to comprise more than one portion of the material transparent to the radiation used for photo-curing and the same number of perforated or lowered portions, and each portion of material transparent to the radiation used for photo-curing has a different refractive index, the difference between the refractive indexes being equal to the shift of the incident ray equal to the pixel size divided by the number of portions of radiation transparent material. - is made entirely of the same material transparent to the radiation utilized for the photo-curing, with one or more perforated or lowered portions with respect to its upper surface, of a size equal to the printing area size, and between said at least one source of a radiation suitable for obtaining photo-curing of the liquid photo-curing material and said mobile support element a system of lenses with different refractive index is interposed, or - alternates, at regular intervals, a portion of a material transparent to the radiation used for the photo-curing, of a size equal to the size of the print area, and a perforated portion or lowered with respect to its upper surface, of a size equal to the size of the printing area, the support element being able to comprise more than one portion of the material transparent to the radiation used for photo-curing and the same number of perforated or lowered portions, and each portion of material transparent to the radiation used for photo-curing has a different refractive index, the difference between the refractive indexes being equal to the shift of the incident ray equal to the pixel size divided by the number of portions of radiation transparent material. <EOS>