EHFs are used to represent frame imperfections. The Eurocode requires they are applied to all combinations. (Lateral wind combinations therefore should also have EHFs applied).
EHFs are automatically derived from the factored load cases within the current combination. They are applied in the analysis as a horizontal force at each beam column intersection as a specified percentage of the vertical load in the column at the column/beam intersection.
Settings that control the EHF percentage can be adjusted from Home > Model Settings > EHF . (The default settings conservatively result in 0.5% EHF in both directions).
EHFs are applied to the structure in the building directions 1 and 2 as follows: