about Semiadditive

About Semiadditive the olap server just intruduce its concept,i don't know how to setting Semiadditive,for example ,some mesures in mesures group just want to be aggregated along geography dimension,not time dimension,how to do it?

Semiaddtive measures have special aggregation behavior only along the time dimension and are additive along all other dimensions. I am not sure I understand your specific requirements. Generally speaking, if you want special aggregation rules along non-time dimensions you can use unary operators or custom rollups.