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#CV-2x3-143

agreement on having the containment tree and the relative placement tree identical for spatial elements
number
CV-2x3-143
based on
IFC2x3
effects
extended coordination view
date
23. May 2007
initiator
ISG meeting in Espoo
summary agreement on having the containment tree and the relative placement tree identical for spatial elements

 

Description

The spatial containment of IfcSpatialStructureElement forms a tree, and the local relative placement of IfcSpatialStructureElement forms another tree - both trees should be identical (i.e. if an IfcBuildingStorey is contained in #201=IFCBUILDING, then the IfcBuildingStorey.ObjectPlacement.PlacementRelTo shall point to the same instance #201=IFCBUILDING.

 

identical containment and placement trees

Figure: the containment and local placement trees.

Added 2010 in official buildingSMART certification 2.0 program

  • the uppermost spatial structure element, either an IfcSite, or an IfcBuilding, that is directly assigned to the IfcProject through Decomoses.RelatingObject, shall have no relative placement.
  • the placement of the uppermost spatial structure element is provided by IfcLocalPlacement with PlacementRelTo = NIL.