ETABS different roof elevation

[McGill10]

Lateral Analysis in ETABS:
A single story building has different roof ht.I mean at one area it is 14 ft high on the other areas it has 20ft and 24 ft high from ground level. Has anybody faced similar situation in thier work? I have problem for lateral anlaysis for wind design,because ETABS wind load distribution at different roof level are not coming right.
ETABS auto wind generate option does not seems helpful here.
Any suggestion would be appreciated.
thanks.

 

[ali07]

apply loads manually at each diaphagms. assign each level as different diaphragm and apply forces at column faces or diaphragm centre. Auto lateral forces have to be double check all the times.