IfcSpace modelling

[Erik Bjornhage]

Sooo...

I have recently had a discussion about IfcSpaces and what is the best way to model them in order to maximise the use for other disciplines.

Looking at the semantic definition and the BaseQuantities of IfcSpace it is clear that the IfcSpace starts at the level of the construction slab and ends at the underside of the construction slab on the story above. However, this is not how we ususally model spaces (zones) as we normally start at the finished floor level.

I know that there is the parameter in the zone to set a value for subfloor thickness - but if we are to model zones "correctly" there should also be a parameter for ceiling height (which exists in the SpaceBaseQuantities). 

So, two questions:

1. Has any had experience of modelling this way or are we all modeling the "architecture" way?
2. Is there a parameter for FinishCeilingHeight hidden somewhere in Archicad? I have not found it...

Operating system used: Windows 11 Pro 24H2

[CarlosGVarq]

Hello, srry if I have rescued this topic and this question has been resolved, but it is a intresting discussion.

I use Cypetherm HE Plus by Cype (from spain) for process bimtobem. This workflow use ifc format and schema, I use clasification in order to translate properties to ifc schema. In this process i need space start "at the level of the construction slab and ends at the underside of the construction slab on the story above". Due to, in the process by cype a software translate geometry model in analytical model. In this point analytical model is a colection of box linked that simulate energy performance.

The correctly performance depend on net volume have been translated of archicad to ifc schema. Before we must change zones in phase bim to bem. If we model spaces slab to slab, and obtain proprerties through expresions and translate we get better a lot this process, avoiding steps.