After the Complex tab is selected in the
Influence line dialog, the following displays.
The options in the dialog box let you indicate a surface-related quantity (defined for a slab or shell structure) for which the influence lines are presented:
Stresses - s - The influence line is a line of reduced stresses s.
Membrane forces - N - The influence line is a line of reduced membrane forces N.
Moments - M - The influence line is a line of reduced moments M.