Curtain Wall Settings: System Page: Positioning Panel

[Anonymous]

HI,
i m using ArchiCAD12.0........ I m wondering......... what is nominal size in curtain wall......... i dint understand........i dint get any change when i change the values.........i think i dint understand the concept.........so can any one help me by explaining with one example....( Curtain Wall Settings: System Page: Positioning Panel - nominal size ).

Thanks in advance..............

[Anonymous]

do you mean nominal thickness?

i can't find the normal size.