Function linear_placement 

pub fn linear_placement(
    tx: &mut Transaction,
    relative_placement: EntityId,
    placement_rel_to: Option<EntityId>,
    cartesian_position: Option<EntityId>,
) -> Result<EntityId, AlignmentError>

Stage an IfcLinearPlacement.

CartesianPosition is optional and deliberately left to the caller: it caches the resolved world position, and this crate will not compute one, since deriving coordinates from an alignment curve belongs to the geometry kernel.

Errors

Never fails; kept fallible for symmetry with its siblings.