Opening's In IfcWallStandardCase are not visible in xBIM viewer.

[CCT-Mukund-Thakare]

I have a certain IFC file that's proving to be a bit problematic. When I load this file in xBIM viewer the IfcWallStandardCase are not rendered properly, meaning opening's are not at all considered while rendering. Consider below snap.

When compared to other viewer I could see opening and window at same place, consider below snap.

I have downloaded the latest version of xBIM viewer and these results are recorded in it. I have attached a file to reproduce the same issue :

Schependomlaan.zip

Expected behavior: Like other viewer, we should be able to see Openings for IfcWallStandardCase.

[CCT-Mukund-Thakare]

@andyward Hello As per you suggestion on issue-418 Continuing the discussions over here.

For this particular issue, I have figured out that the issue is in OCCT version that we are using. Check out below Analysis,

I opened this file in different CAD Assistant versions and found that till OCCT verisons 7.3.1 it was working fine and then afterwards the bug started occurring.

1) 1.2.1 & OCCT 7.3.1.dev 2) 1.3.0 & OCCT 7.3.1.dev

3) 1.4.2 & OCCT 7.4.0dev 4) 1.5.0 & OCCT - 7.6.0.dev 5) 1.6.1 & OCCT - 7.7.0.dev

Currently on version6 (netcore branch) Xbim Team is using OCCT 7.7.0.beta version and the issue is still there with this OCCT version. I was planning to downgrade the OCCT version and then build geometry package to resolve this issue. Let me know your thoughts on downgrading the OCCT version on netcore branch.

Someone have also discussed the similar issue on this link.

Thank you !!

[andyward]

Hi @CCT-Mukund-Thakare - This is great analysis! Thanks for this.

If it's truly a OCC regression, have you determined if it is a known issue and logged with OCC? (there may be workarounds if there's a ticket)

I'd suggest you want to isolate a specific issue into a smaller IFC and work with that (i.e. the Wall an its openings). While it's appearing as an issue in OCC it may also be a tolerances issue that we can do something about on the xbim side. If you can get the issue in a failing unit test it's a great starting point.

In terms of downgrading OCC, I'd tend to suggest upgrading to 7.8.0 might be more productive - 7.7 fixed a bunch of other issues. GE6 uses a nuget packaged version of OCC - we'd need to publish 7.8+. If you look at 7.3.1 (which is ancient) there's all kinds of other issues, so I'm not feeling like that's a step forward. But looking at the 7.4 changelogs may indicate what changed.

@SteveLockley do you have some time to update / publish the Xbim.Occt project?

[CCT-Mukund-Thakare]

Hello @andyward Thank you for your suggestions, after reading your previous comment I have decided not to downgrade the OCC version to fix this particular issue instead I will wait for the Xbim.Occt projects new release.

I have raised this particular issue at the OCCT forum as well and they have acknowledge it, here is the link. https://tracker.dev.opencascade.org/view.php?id=33614

Hello @SteveLockley Is there any tentative timeline for update\release on the Xbim.Occt project ?

Thank you !!