See also: BranchID, ParentID
Returns the unique variable ID associated with the specified branch:variable reference or with the specified name. Names can be those of either the built-in variables (such as "Activity Level" or "Final Energy Intensity") or the names of additional user-defined variables. This function can be useful when you need to pass information about the LEAP tree structure to an external script or DLL.
Energy Intensity) = 2040 (the ID of the final energy intensity variable)
VariableID(Demand\Household\Refrigeration:Activity Level) = 2027 (the ID of the activity level variable)
VariableID(My User Variable) = the ID of the added user variable named "My User Variable"