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buildingSMART / NextGen-IFC

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Mirroring #86

Open theoryshaw opened 3 years ago

theoryshaw commented 3 years ago

Is there an nice way to accommodate mirroring objects in the schema?

If not, is it possible to propose one for the NextGen?

cross-posted to: https://forums.buildingsmart.org/t/mirroring/3688

jwouellette commented 3 years ago

Ooof. Mirroring seems to be such a major pain to handle correctly. From my perspective, it's an end user convenience/shortcut to duplicate things graphically, but ends up being a total data nightmare. Seems to me that in the BIM universe, mirroring is a curse more than a solution.

Maybe it would help by clarifying exactly "what" can be mirrored and acceptable and what can't. Like the difference of supporting simple objects with bilateral symmetry (e.g. toilets) versus entire unitized constructs (e.g. unit plans for flats).

TimSharrock commented 3 years ago

In the shipbuilding world (not the central target for IFC, but our customers do use it) mirroring is very important (the port side and the starboard side of the hull generally start as mirror images, and many of the parts that make it up remain so). Handling this correctly for all operations does tend to be a source of bugs :(

theoryshaw commented 2 years ago

caught in the wild: https://github.com/IfcOpenShell/IfcOpenShell/issues/1496

let4mi commented 1 year ago

Is there any news on this topic? Any plans to include various ideas and proposals related to mirrored objects/projects in IFC5 development? I do understand that this is a complicated issue, but this is also usually used as an excuse by specific vendors for stopping development and allowing ifc exports of such a files. While on the other hand, all this time, different vendors are allowing it, export IFCs with mirrored objects or linked projects and use it without bigger issues at the moment. I don't see much of discussions of a negatives or possible drawbacks on the current implementations done.