When doing cross section optimization with the “Optimize Cross Section”-component, the design formulas applied take account of buckling, based on the buckling length of the members. By default local buckling of individual elements is assumed. So-called global buckling occurs if a structural sub-system consisting of several elements (like e.g. a truss) loses stability. Global buckling can be checked with the “Buckling Modes”-component (see fig. 126.96.36.199).