Answer:
For crane girders that are supported laterally by a semi-rigid spring (sway bracing), it is possible to set Method 3 as "Allowable Deformations" in Details. This way, the length for determination of the allowable deformation is related to the inflection points of the deformed member axis.
If you want to relate the allowable deformation to the distance between the start and end supports, you have to calculate it manually.
