buildingSMART Forums

Space category in IFC 4


Hi there

I was looking for a topic about space categories but I didn’t find anything.

In IFC 2x3 there was an attribute named “category” in Pset_SpaceCommon for Category of space usage or utilization of the area. It is defined according to the presiding national building code.

In IFC 4add2 this attribute does not exist anymore. What kind of attribute should I use therefor?

Thank you for your answer!


Hi @ugogreco,

If you look at the entry for IfcSpace and scroll down to:

You will find:

The following guidelines should apply for using the Name, Description, LongName and ObjectType attributes.

Name holds the unique name (or space number) from the plan.
Description holds any additional information field the user may have specified, there are no further recommendations.
LongName holds the full name of the space, it is often used in addition to the Name, if a number is assigned to the room, then the descriptive name is exchanged as LongName.
ObjectType holds the space type, i.e. usually the functional category of the space .

Does this help?


Hi @jwouellette

Thanks for your answer.

Of course, I ignored the possibility of ObjectType.

But the “functional category” is used for values like Bathroom, kitchen, staircase, etc. or not? I need an attribute for another room area category according to the Swiss standard. Should I create my own for this?


I suppose you could use either Pset_Space OccupancyRequirements or most likely IfcClassification. Part of it depends on if there is a specific MVD that prescribes where it goes.


the reason behind not having the category attribute in Pset_SpaceCommon in IFC4 was to rationalize the use of types and classifications. As in all other elements, including physical elements, you can:

  • classify by predefinedType/objectType or link to external classification system (there is a similar issue here in the forum)
  • use a project specific type by either using IfcSpaceType.Name or Pset_SpaceCommon.Reference (there was also a discussion about it)

so there should not yet be another way (IFC already often has too many options).



thanks to both of you for your answers.

As mentioned above, I think the approach for classifying the spaces by to be the best and right solution.