A family of European standards (EN 1990-1999) defining structural design rules - loads, materials, seismic design - that a structural analytical model must be checked against on projects following European practice. Eurocode 1 defines the loads, Eurocode 8 covers seismic design, and so on - a structural engineer sets up load combinations in a tool like Robot Structural Analysis according to whichever code governs the project's jurisdiction, Eurocode being the most common outside North America.