Function create_layer_set_usage 

pub fn create_layer_set_usage(
    tx: &mut Transaction,
    model: &Model,
    for_layer_set: EntityId,
    direction: LayerSetDirection,
    sense: DirectionSense,
    offset_from_reference_line: f64,
    reference_extent: Option<f64>,
) -> MaterialResult<EntityId>

Stage an IfcMaterialLayerSetUsage.

Direction and sense are typed enums rather than strings: an invalid token cannot be constructed, so no runtime check is needed for them.

Errors

Refuses a set that is not an IfcMaterialLayerSet, a non-finite offset, and a reference_extent for IFC2X3, which has no ReferenceExtent.