A structural element forms a motor vehicle dashboard body that is intended to be installed in a transverse installation position inside a vehicle passenger compartment. The structural element has a one-piece openwork structure produced by three-dimensional printing. The openwork structure defines: a first internal passage that passes all the way through the structural element and extends transversely when the structural element is in the installation position. The first passage is shaped so as to receive a crossmember that is in particular bent with a constant radius of curvature and having at least two fastening elements that are intended to be fastened to the crossmember. A second internal passage connects the first passage to a face of the structural element that is directed toward the rear of the vehicle when the structural element is in the installation position. The second passage has at least one fastening element that is intended to fasten a steering column fastening support.