Relation between doors to rooms

Developers
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Hi,
in our CAFM projects, a frequently occurring requirement to the IFC models is that a door contained in a model provides information on which two rooms it establishes a connection between (e.g. for the locking system management or the access permissions). An automatic evaluation based on the opening direction is not sufficient, since in the example of locking systems, the opening direction is not always decisive for the room to which the door grants access. In our opinion, it would be reasonable to establish a fromRoom or toRoom relationship between ifcDoor and ifcSpace. This could be used for different purposes depending on the use case - the opening direction, access permissions, etc.
Some weeks ago I was involved in a discussion about that, which came up with a proposal. Thomas Liebich was so kind to visualize this - thanks at this point for that. Unfortunately, since I am a new user here, I can neigther upload the image of the scheme with my post, nor paste in a direct link. You can view the scheme unter the following link without spaces:
https:// etask. blob. core. windows. net/neu/Proposal_IfcDoor-Space_Relationship.pdf

Does the approach seem reasonable to you?

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Hi @MZibell ,

The image post policy is part of the system. New users are restricted until they’ve spent more time and effort on the board. This helps cut down on spam.

I’ve included your image here:
Proposal_IfcDoor-Space_Relationship.pdf (119.5 KB)
for easier access by everyone.

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Did you consider IfcRelConnectsWithRealizingElements as well? In my view, it’s be easier to assert correct cardinalities. And the information of the space connectivity is contained within a single relationship rather than spread out over two. With e.g <RelatingElement, RelatedElement> being <From space, To Space> and RealizingElements being the {IfcDoor}.

If you’re interested in a way to derive these relationships from existing models you can have a look here Relationships in IFC — OSArch Community where we use space geometry and element placement for efficiency.

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Could utilizing Space Boundaries be relevant here? https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/link/ifcrelspaceboundary.htm? The door swing direction as such should be identified by IfcDoorStyleOperationEnum.

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Yes. One French software editor in FM domain do so.

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Connections should be more generalized than just with doors. The opening creates the connection (or the wall does beforehand), the door fills the void. If we remove the door the opening remains and so should the connection.

The “from” and “to” are not always related to the door opening direction. So an explicit relationship is necessary IMHO