The changes to the "Building Positioning" graph are all in this screenshot:
Changes:
"Select Main Building" Node: Replace "Select Family Instance" node with "Select Model Element". The building couldn't actually be selected since it's not a family instance.
Nodes for extracting the position were updated since mass objects don't have a location property, so Element.GetLocation no longer worked.
Reorganized the graph a bit to make room for the new nodes.
@mrahmaniasl
The changes to the "Building Positioning" graph are all in this screenshot:
Changes:
Element.GetLocation
no longer worked.