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buildingSMART / IFC4.4.x-development

Development of IFC 4.4
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Proposal to formalise how property set templates are applicable to external classification systems #12

Open Moult opened 3 years ago

Moult commented 3 years ago

Resurrecting and taking a fresh look at @jmirtsch 's question here. Here is my paraphrase:

Currently, IfcPropertySetTemplate has an ApplicableEntity attribute which denotes whether or not it is applicable to a particular IFC class and predefined type. However, what if a user wants to say that a property set template is applicable to an element classified using an external classification system, such as Uniclass / Omniclass / etc? @jmirtsch proposes to use the existing HasAssociation attribute.

This has no change to the schema, but may require an additional section in the documentation describing that this relationship can be used this way.

Thoughts? Also, does recent developments with the bSDD impact this proposal in any way?

Personally, I think the proposal makes sense.

Ping @TLiebich @berlotti @aothms

aothms commented 2 years ago

One concern is that this scatters out the act of establishing the applicability over different places, which is error prone and not discoverable by implementers.

If we go ahead with supporting this, we could look into modifying the type of Applicable(Entity) and in the mean time make it a proper sequence and use semantic structure for entity/predefined type.

We need more input on this in terms of requirements, scope of IFC, and general handling of externally defined content.