For the "Buckling Mode" imperfection type, the result from the stability analysis is used and the precamber is applied in the direction of the mode shape of a given load combination.
The load combination can be specified in the "Buckling Mode" tab and should belong to the smallest critical load factor. Furthermore, you can also specify the scaling direction in this tab. The length of the member is taken from the graphic using the "Measure" option by selecting the member start and the member end one after the other (3). Then, the measured value has to be divided by 200 (4).
In this case, the initial bow will look like the mode shape.
This procedure of applying an imperfection is well suited for a few members that may have complicated boundary conditions, so it is not possible to immediately assess what is the approach of the most unfavorable imperfection. However, this variant is not suitable if you want to design a large number of members. For example, it would be necessary first to find a separate buckling configuration in a load combination in which this stringer fails. Furthermore, each buckling mode would have to be scaled individually.