There are 3 methods to calculate the buckling lengths:

- Non-displaceabable nodes (syn.: non-sway buckling lengths)
- Semi-displaceabable nodes
- Displaceabable nodes (syn.: sway buckling lengths)

The prefered method depends on the sway or non-sway character of the structure and if global imperfections have been taken into account.

The diagram below gives an overview.

- The red paths are possible in Diamonds.
- Instead of non-sway buckling lengths, you may also use the semi-displaceable nodes as a conservative alternative.

(Source diagram: *Krachtswerking, Grondslagen voor het berekenen en toetsen van staalconstructies voor gebouwen volgens Eurocode 0, 1 en 3, H.H. Snijder en H.M.G.M. Steenbergen, Bouwen met staal, 2011, ISBN 978-90-72830-87-6*)