Support constructions are often modeled by spring elements connecting a structural node to the rigid ground modeled by referencing the node ‘0’. Elements connected to node ‘0’ have by default a zero length. Their local coordinate systems cannot be derived from the element axis and are therefore established with global directions. This also applies to all other spring elements connecting 2 structural points with identical coordinates (e.g., for modeling bridge bearings). In order to get a local coordinate system with other than global directions, it must be defined by directly specifying the appropriate angles α₁, α₂ and β. The default local system for β=0 is created in accordance with the above described deck element convention. The lengths of these elements must also be specified by the user (for plotting purposes).