Buckling is a critical failure condition for many classes of structure. Accurate estimates of critical load and response modes are difficult unless a structure falls well into the ‘slender’ category. Linear solutions may suit such structures if loads and boundary conditions are carefully assessed. However for the majority of instability prone structures a full nonlinear analysis is required. This type of analysis is very sensitive to assumptions on eccentricity and boundary conditions. A methodology is required that will deal with structural softening. The key point method is recommended to help identify onset of instability and subsequent transitional modes.