See also: ParentID, VariableID
Returns the ID of the Nth sibling of either the current branch or the specified branch:variable reference. This function can be useful when you need to pass information about the LEAP tree structure to an external script or DLL. Index is the number of the sibling from 1..N, where N is the number of immediately neighboring branches of the referenced branch.
the ID of the 2nd branch in a group of neighboring branches.