Hiding optical defect lines on parts of fdm printed luminaires with metallic look

A method for manufacturing a reflector by 3D printing on a substrate, the method comprising providing a filament of 3D printable material and printing during a printing stage the 3D printable material, to provide said reflector comprising 3D printed material, wherein the 3D printable material comprises light transmissive polymeric material and wherein the polymeric material has a glass transition temperature, wherein the 3D printable material during at least part of the printing stage further comprises plate-like particles, wherein the plate-like particles have a metallic appearance, wherein the plate-like particles have a longest dimension length (L1) selected from the range of 40 μm-2 mm and a largest thickness (L2) selected from the range of 0.05-20 μm, and wherein the method further comprises at least temporarily heating the substrate to a temperature of at least 5° C. above the glass transition temperature at least during deposition and/or after deposition of a first layer of 3D printable material on the substrate executed until essentially the deposited first layer is conformal with the substrate.