I don't think it would help. The fundamental issue is that the current express-based IFC has no kind of data-model level intelligence where data can be 'inherited' over instances. Everything needs to

@aothms what's your thoughts. Do you think IfcRelDefinesByObject needs to be implemented on the C++ side of things?

'IfcRelDefinesByObject' does look promising.

@theoryshaw It could be useful to use collection instances and delay the "refresh" to be used only when the file is saved. It would still be slow but it would be used only once. Howe

I would love to see the implementation of IfcRelDefinesByObject in Bonsai.

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@VDobranov This is really good. I was looking on working on IfcRelDefinesByObject just about a week back. Will test this out now.

It’s been three months already, but thanks to a burst of activity lately, I seem to have managed to create an example file with IfcRelDefinesByObject relations.

I'd like to explore the idea of working with IfcRelDefinesByObject and IfcElementAssemblyType, but it seems to be a big task right now. So my plan is to make "Linked Aggregate" a sta

Others have discussed it as well. It seems from the discussions that IfcRelDefinesByObject might be the way to do it. Sounds complicated. Not sure IfcOpenShell accommodates this functionality na

This discussion was created from comments split from: BlenderBIM: Arrays, IfcRelAggregates, IfcOpeningElements, IfcMaterials.

* The IfcRelDefinesByObject page has some insightful pics explaining how the types should aggregate occurences which are defined by their own types:

I would have to ask if its IsDeclaredBy(IfcRelDefinesByObject@RelatedObjects) attribute has any stored value.

I am struggling to understand the difference between IfcRelDefinesByObject and IfcRelDefinesByType.

From what i can gather, from this conversation here, that IfcRelDefinesByObject would be the way to accomodate a type within a type.

would this IfcRelDefinesByObject approach, be a way to address this?

buildingsmart.org/IFC/RELEASE/IFC4x3/HTML/lexical/IfcRelDefinesByObject.htm

IfcRelDefinesByObject can be a solution ... but if allowed ...

Regarding you UI/backend proposal, I don't understand why you link Tasks between themselves with IfcRelDefinesByObject. Is that allowed, and what for?

- a definition relationship <em>IfcRelDefinesByObject</em> that uses a component of a type definition (a part of a type, called the "declaring part") to