The invention provides a 3D printed object (210) and a method of manufacturing such an object (210) by means of fused de-position modelling. The method successively comprises the steps of (i) 3D printing a printable material (120) to create a layer stack (230) of printed material (210), wherein the layer stack (210) bounds a space (240), wherein the layer stack (210) has an inner stack surface (231) and an outer stack surface (232), the inner stack surface (231) facing towards the space (240) and the outer stack surface (232) facing away from the space (240), (ii) providing a heat shrink (250) onto the layer stack (230), wherein the heat shrink (250) has an inner heat shrink surface (251) and an outer heat shrink surface (252), the inner heat shrink surface (251) facing towards the outer stack surface (232) and the outer heat shrink surface (252) facing away from the outer stack surface (232), and (iii) applying heat to shrink (250) the heat shrink so that the inner heat shrink surface (251) is in physical contact with the outer stack surface (232) and the heat shrink (250) is conformal to the layer stack (230). The layer stack (230) is light transmissive, and the heat shrink (250) is arranged to provide an optical effect chosen from the group consisting of refraction, diffraction, reflection, diffusion and conversion. The 3D printed object (210) may be used as a component of a lighting device (600), such as a lampshade.