Every IfcAlignment must be related to IfcProject using the IfcRelAggregates relationship - either directly or indirectly. The indirect case is when a child alignment is aggregated to a parent alignment. In this case, only the parent alignment must be related to IfcProject.
The following diagram shows the generic classes and relationships used when applying this concept.
In addition, concepts may have particular importance to common or standardised industry practices and scenarios. For these specific usage scenarios, the table below shows a recommended list of general usage patterns that users may adopt.