ESO has utilised the innovative technology of 3D printing to manufacture moulds for the casting of two new components required for the MUSE instrument on ESO's Very Large Telescope (VLT) in Chile. This technique offers great promise in the manufacture of complex custom items, which are often needed in astronomical instrumentation, delivering the components more quickly and cheaply and with greater flexibility. The component, the structural body of a new sensor arm, appears in the centre of the picture and is the mounting point for three mirrors.