buildingSMART Forums

IFC 2x3 implementation agreements status in IFC4+

https://standards.buildingsmart.org/documents/Implementation/IFC_Implementation_Agreements/

Is it safe to say that every CV is either directly implemented in IFC4+ or it is implied that CV holds true for every IFC schema version? Should CV’s be updates for newer schemas?

This has been proposed 3 months ago, but either no action has been taken, or that action is behind closed doors: https://github.com/buildingSMART/NextGen-IFC/issues/42

I find it odd that buildingSMART decides to lock these issues instead of letting the community continue to address them. There is no avenue to follow-up on these requests, @TLiebich mentioned a Git repository, but none has been communicated in this forum (or did I miss it?)

With no communication, I share @claimred’s concern that the implementer agreements need revisiting, and either merging into the IFC4 documentation, or obsoleting.

1 Like

There was an attempt several years ago to go through every single IFC2x3 CV and decide if it was still relevant or not. The general consensus was that IFC4 should generally have no CVs, and that everything should be included as part of the base documentation. I don’t know where that suggestion stands re: the current documentation.

@angel.velez I’ve heard that too as that was the theory. In practice, however, some CVs are still used to resolve ambiguous behaviour (e.g. the whole material / surface colour issue)

1 Like

Exactly, yeah. Colors issue is definitely a hot topic.

A couple of CVs we were wondering about are about Doors and Windows.

https://standards.buildingsmart.org/documents/Implementation/IFC_Implementation_Agreements/CV-2x3-178.html

https://standards.buildingsmart.org/documents/Implementation/IFC_Implementation_Agreements/CV-2x3-181.html

CV-2x3-181 in particular is confusing imho. Parametric doors/windows representation (i.e. ParameterTakesPrecedence = TRUE attribute value) is still in IFC4+ schemas without deprecated flags. Yet, it’s mentioned in the CV that it should always be false, explicit geometry should be provided and not rely on LiningProperties.

First, it’s just a bit weird not to be able to have parametric doors representation in IFC, isn’t it? Especially considering DTV is on it’s way.

Second, there is a special check report example about certain door/window objects where there is implied that https://b-cert.org/Documentation/CheckReportExample.

Am I missing something?