http://sqlblog.com/blogs/marco_russo/archive/2011/07/22/parent-child-special-calculations-in-bism-tabular-denali.aspxAlberto Ferrari published an interesting blog post regarding how to write particular calculations over a parent-child hierarchy in PowerPivot Denali (and in BISM Tabular, of course). One case is the Sum of Leaves (summing only the leaves of a parent-childenCommunityServer 2.1 SP2 (Build: 61129.1)