Connected with the invention of the planetarium is the design of the projection dome. The planetarium projection requires an exactly spherical projection surface. Walther Bauersfeld also addressed this problem. He designed a network of steel rods that served as a geodesic support structure for both the projection dome and the dome building. The Jena Planetarium was one of the first buildings to be built with such a rod network. It serves as a support element for a concrete layer. The thin-walled construction not only found its way into planetarium buildings, but also revolutionized architecture and construction technology.