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GetLine doesn't support all entity types (only IFC4?)
Hi, thanks for the great work on webIFC!
We fail to retrieve the raw data for some entities via ifcAPI.GetLine(modelID, expressID). This happens for example with IfcElectricDistributionPoint entities. My base assumption is that webIFC applies the IFC4 scheme to all IFC files and so it's missing entities types that only exist in IFC2x3, like IfcElectricDistributionPoint.
The official scheme versions 2.3.0.1 and 4.0.2.1 have quite an overlap of common entities, but also a solid chunk of entities that are unique to each version. For what it's worth, here is the comparison:
It appears like the 114 entity types that are unique to IFC2x3 might be unsupported. Since the attributes of an entity type can also change between versions, it would be best practice to process IFC files according to the used scheme version. Applying the same scheme to all files might produce some 2nd level effects like mismatching attributes etc.
I attached a sample file with two IfcElectricDistributionPoint instances and also a list of all entity types that are unique to IFC2x3.
Thanks for looking into it!
IFC2301_unique_entities.txt Sample_file.zip
Here's an example of mismatching attribute names due to mismatching data schemes. In the classification concept, there's an attribute that holds the actual classification code (red in image):
This attribute changed its name from "ItemReference"(IFC2x3) to "Identification" (IFC4).
webIFC outputs "Identification" for both IFC2x3 and IFC4 files. Also note the other entries in the change log for this entity alone. IFC is complex and inconsistent already, so parsing a file against a mismatching data scheme will only create more problems. I hope this example helps to illustrate why webIFC should at least distinguish the 2 official scheme versions 2.3.0.1 and 4.0.2.1.
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Hi, @beachtom! Thanks for taking this bounty! The due date is December 9, 2022 UTC.
If you need to submit some pull requests (PR) to complete the tasks, make sure that the last and only the last PR has a title that either starts with the bounty ID or is exactly the same as the bounty name. After the PR is merged, this bounty’s status will automatically changed to done.
If you do not need to make a PR, tell the manager @agviegas to run ::done command after your tasks is confirmed to be done.
Good luck!
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Thanks @beachtom, looking forward to testing this one! This fix is quite substantial for all those who work from the raw data in IFC and need to acess all entities in a reliable way :-)