Techniques are disclosed to enable manufacture of open-air corner-cube retroreflectors having a corner-cube cavity. The techniques involve additively forming a substrate by way of additive manufacturing technologies such as three-dimensional printing technologies. The techniques further involve optionally machining the additively formed surface of the substrate and replicating a reflective surface in the corner-cube cavity using a master that is coated with a reflective material. An adhesive is applied to the corner-cube cavity so that when the adhesive cures and the master is withdrawn from the corner-cube cavity, the reflective surface adheres to the adhesive and remains an integral part of the retroreflector.