Function oriented_edge 

pub fn oriented_edge(
    tx: &mut Transaction,
    element: EntityId,
    orientation: bool,
) -> EntityId

Stage an IfcOrientedEdge over an existing edge.

The inherited EdgeStart and EdgeEnd are written Value::Derived – * in STEP – because the schema derives them from EdgeElement. Writing $ there would claim they are absent, which is a different and non-conforming statement. See the module note.