IfcZone & Model Tree

I’m interesest to understand how the class IfcZone sits in the model heirarchy.

  • Q1: Are there any differences between how IfcZone operates in Ifc2x3 and Ifc4?
  • Q2: Does IfcZone sit in parallel with IfcZone as part of IfcBuilding?
  • Q3: Does IfcZone sit between IfcBuilding and IfcSpace, i.e. is IfcSpace a subset of IfcZone?

Model tree examples would be useful.

Many thanks

IfcZone is just a grouping of IfcSpaces. No geometry, no fixed hierarchy, not part of Spatial Structure tree.

A zone is a group of spaces, partial spaces or other zones. These spaces may or may not be adjacent. A zone does not have its own shape representation. Zone structures may not be hierarchical (in contrary to the spatial structure of a project - see IfcSpatialStructureElement ), i.e. one individual IfcSpace may be associated with zero, one, or several IfcZone 's. IfcSpace 's are grouped into an IfcZone by using the objectified relationship IfcRelAssignsToGroup as specified at the supertype IfcGroup . For example, a zone might be used to represent an apartment as a group of spaces.

It is considered a System and behaves as a Group

The IfcZone is regarded as the spatial system (as compared to the building service, electrical, or analytical system), the name remains IfcZone for compatibility reasons, instead of using a proper naming convention, like IfcSpatialSystem.

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@cgee Hello. Please, take a look at the IfcSpatialZone project. Here is a good summary shared during the last bSI Summit in Rome (just click the image for the youtube video):


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