The architectural-structural workflow usually requires several “round trips” of information exchange. For example, depending on the results of strength analysis and design calculations, the structural engineer may propose changes in the size (thickness, height, profile etc.) and the position of structural elements. Many applications, including ARCHICAD, have functions that serve to detect and manage these geometrical changes. ARCHICAD’s model-based change management feature and the Trace & Reference tool help to keep this process transparent.