To determine λ_cr for a particular member axis, the drift due to notional loads applied in the direction of the axis is required to be calculated. However, the notional loads are currently only generated along the models global axis, as illustrated below for gravity dead and live notional loads:

Given a specific member axis orientation the program will calculate the correct components of the orthogonal notional loads to obtain the required force in the direction of the axis of the member (frame). So for a column major axis oriented as illustrated below (where α = 30 degrees), the components of the orthogonal notional loads required to be applied simultaneously to achieve a 30 degree applied force are as follows:

For Notional Dead: NDx Cos (30) + NDy Sin (30) = 0.866NDx + 0.5NDy

For Notional Live: NLx Cos (30) + NLy Sin (30) = 0.866NLx + 0.5NLy

Note that when these expanded terms are applied to a load combination such as 1.2ND + 1.2NL the load combination will expand to the following:

1.2 (0.866NDx + 0.5NDy) + 1.2 (0.866NLx + 0.5NLy)

This will be applied and appear as follows in the generated report:

1.04NDx + 0.6NDy + 1.04NLx + 0.6NLy.