title: MDX Calculated member Sum of selected members rollup
body: <p>I'm trying to write a calculated member that will roll up along a dimension based on the selected values provided on the axes.</p>
  
  <p>Product -> subcategory -> category
  lexus -> sedan -> car
  lexus-coupe -> coupe -> car
  bmw -> sedan -> car
  bmw-coupe -> couple -> car
  ford -> pickup -> truck
  chev -> pickup -> truck
  ford-suv -> suv -> truck
  lincoln-nav -> suv -> truck</p>
  
  <p>[Calculated measure] = [measures].[a]+[measures].[b]</p>
  
  <p>suppose the user wants to see [Calculated measure] at the car level for just lexus-coupe and bmw.  How do you create a calculated measure that will roll up at the car level based on what has been selected in the dimension?</p>
  
  <p>Thank you in advance!</p>