IFC/BIM

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markus23
Posts: 12
Joined: Sun May 24, 2020 11:35 am

IFC/BIM

Post by markus23 »

Dear community,

we are developing a new workbench for BIM energy calculations and need more reliable and faster IFC import for large buildings.

Ideally, you live in EU or even in Austria; and speak English or even German.

Wanted Qualifications:
  • Experience with FreeCAD
  • Willingness to work with the FreeCAD community
  • C++ and Python expertise
  • Ideally experience with IfcOpenShell and OpenCascade
Possible Topics:
  • Development of IFC regression tests
  • IfcOpenShell bug fixes
  • Misc. fixes related to large models
  • Profiling of IFC import and generally loading of large models
  • Improving of documentation
We intend to contribute most of your code written in this job to FreeCAD and IfcOpenShell.

If you are interested working part-time on this topic, please contact me.

best regards,
Markus
vocx
Veteran
Posts: 5197
Joined: Thu Oct 18, 2018 9:18 pm

Re: IFC/BIM

Post by vocx »

markus23 wrote: Sat Jul 11, 2020 1:43 pm we are developing a new workbench for BIM energy calculations and need more reliable and faster IFC import for large buildings.
...
Yorik, the main developer of Arch/BIM, has just recently published improvements on the IFC importer. To test them you need to use the most recent version of v0.19 and of the BIM Workbench.

BIM/Arch development news articles from Yorik's blog
yorik wrote: Fri Jul 10, 2020 2:07 pm Multicore IFC importer

This is certainly the most exciting improvement of this month. IfcOpenShell, the engine behind FreeCAD's IFC import/export functionality, has implemented a multi-core mode, able to use more than one CPU process simultaneously to process IFC files. Together, it also implemented a very efficient iterator that steps over the different elements of an IFC file with much more efficiency than the default query system we were using until now.

I started implementing the iterator in FreeCAD's IFC importer, and, although it still crashes a lot when using more than one CPU process, even with just one, the results are baffling: Importing IFC files in FreeCAD now takes about 1/5 of the time it uses to take with the former importer.

... but in any case it really opens the door to working with much larger BIM datasets in FreeCAD.

...
On my way to test with gigantic files now!
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markus23
Posts: 12
Joined: Sun May 24, 2020 11:35 am

Re: IFC/BIM

Post by markus23 »

vocx wrote: Sat Jul 11, 2020 4:15 pm Yorik, the main developer of Arch/BIM, has just recently published improvements on the IFC importer. To test them you need to use the most recent version of v0.19 and of the BIM Workbench.
We are of course using the latest version of FreeCAD and BIM Workbench and this gives us hope that the BIM energy calculations on realistic buildings will be doable within a reasonable time frame. Nevertheless, status-quo (with experimental IFC importer with "Numbers of cores to use" 8 with a fairly decent computer) is still importing time from several hours (one hour without GUI). The problem is also not only within the IFC importer, also opening of huge FCStd files takes hours.

Furthermore, in such big models (office buildings or similar) the usability really suffers at many areas also during working, e.g., auto-save takes very long.

If you want a taste of such a model to play around: https://friends.ccbib.org/lambda/segfault.ifc
It even segfaults because of a bug in IfcOpenShell, see https://github.com/IfcOpenShell/IfcOpenShell/issues/904
Unfortunately, it is only an example building, real buildings we cannot publish because of copyrights by the architects.

Whoever will get the job will of course get access to all these big buildings :D
BIM Bo
Posts: 40
Joined: Sun Nov 22, 2020 3:55 pm

Re: IFC/BIM

Post by BIM Bo »

markus23 wrote: Sat Jul 11, 2020 6:26 pm If you want a taste of such a model to play around: https://friends.ccbib.org/lambda/segfault.ifc
It even segfaults because of a bug in IfcOpenShell, see https://github.com/IfcOpenShell/IfcOpenShell/issues/904
Are you sure it's not the segfault.ifc model that is broken? Just tried to import it with ifc++

Code: Select all

malloc_consolidate(): invalid chunk size
Aborted (core dumped)
at some 74%.

As that is a completely different software stack than IfcOpenShell, and also validated across many other IFC models, I tend to believe the data is broken.
markus23
Posts: 12
Joined: Sun May 24, 2020 11:35 am

Re: IFC/BIM

Post by markus23 »

segfault.ifc is actually a demonstration of how IFC files should look like from a big commercial vendor. Of course this does not exclude the possibility that the file has a problem but any IFC parser should at least tell what the problem is and not segfault. We agree that in any case software should not segfault, do we?
lalberts
Posts: 87
Joined: Fri Feb 05, 2016 2:40 pm
Location: Esslingen am Neckar

Re: IFC/BIM

Post by lalberts »

Time has gone.. how is your Project advancing ?
Did check the OSarch.org site? some guys are active on this there.
Not sure they are ready, seems like the voids in models still make troubles.
Cyril at EPFL is working on it. check for BIM2BEM or so..
https://community.osarch.org/discussion ... mment_5198

Lukas
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