[blender bim] linking ifc file inside converted ifc

i made 2 files that converted from revit. due to come condition i cannot convert it to ifc 4 so i only can converted it to 2x3.

first i open new fresh page of my blender bim. i linked these 2 files with false origin resulting that it was properly placed.

but on the second when i try opened one of the ifc files (i need to open the files since i was editing that files meanwhile the other only for referenced of other discipline), it was not correctly placed.

another condition is ; these 2 files have different units. meter & milimeter

this is condition when i make new fresh page in blender bim, and linked these 2. it properly placed
![](https:/
/community.osarch.org/uploads/editor/ep/k3wu3dr0kkmk.png "")

and this is when i opened ifc files and linked the other one inside this file

this is the first file georeference

and this is the second

maybe you will see these 2 georeference different, but when i linked using new fresh blender bim page why it was correctly placed i don't know. so for now i don't know what should i do to correcting those modelwhile i can opened and edit one of those files. anyone can help me?

Comments

  • In the last stable release, if you open a model, it will not only auto detect a false origin, it will also auto detect a project north. However, linking only can handle false origins, not rotations for project north. This is why your opened model is orthogonal and the linked model is not, and so they don't line up.

    This has already been fixed in the latest unstable version and will be available in the next release. Now both opening and linking can handle rotations.

    emiliotassoatomkarincaJohn
  • ah so it will be available in the next release, thank you moult !


  • hi i already update bbim to latest unstable version, but it seems when i open the file it still orthogonal while linking can be placed properly.
    am i missing something?

  • Did you delete or disable the cache when linking? The false origin and project north detection between opening and linking should be identical.

  • edited July 2024


    you mean this one? no, i dont.

    let me more detail about the condition:

    i use 2 files in this drawing, site files, and architecture files. while site files using meter as unit, the architecture files using milimeter as units.
    both of them are exported from revit. and since i have problem in converting to ifc4 i used ifc2x3 format.
    then i start adjust the coordinate, by convert it to ifc4 in blender files dialog menu. and do some ifcmapconversion in georeferencing part. which i adjust the architecture files so the coordinate same (since the units different, i adjust it in different digits)

    here's the georeference in "site" files

    and here's georeference in "architecture files

  • Can you update to the latest BBIM alpha version? It has an improved georef viz which should help clarify some things.

    However from a glance it looks as though your models do have very different georef data which can explain why they don't line up. In particular one has a grid north and the other doesn't.

    You can also join the live osarch chat and we can screen share. Its a bit hard to see sometimes just from forum posts.

  • the one that have grid north is the 'architecture' files, which is i manually georeferenced based in 'site' file. so the 'site' file still in ifc 2x3 version.
    i'm sorry if it make you confused :D maybe i need to joint live chat like you said. what time you guys available?

  • I'm generally online during the Sydney timezone in the live chat. It's also best if you can share your model ([email protected] if private)

  • hi moult, it seems like what you said was right, it's my files geolocation problem. using ai chat gpt, i try to generate ifcopenshell code to aligned my two files geolocation data, it's the code :

    import ifcopenshell
    Load the IFC files
    file1_path = '/mnt/data/4565-CVL-SITE_tx27-4565-ARC-PRODUCTION_tx27_CVL.ifc'
    file2_path = '/mnt/data/4565-CVL-SITE_tx27-4565-ARC-PRODUCTION_tx27_CVL-IFC4_.ifc'
    Open the IFC files
    ifc_file1 = ifcopenshell.open(file1_path)
    ifc_file2 = ifcopenshell.open(file2_path)
    Get the geolocation and project north information
    def get_geolocation(ifc_file):
    site = ifc_file.by_type('IfcSite')[0]
    project = ifc_file.by_type('IfcProject')[0]

    Get the location
    latitude = site.RefLatitude
    longitude = site.RefLongitude
    elevation = site.RefElevation

    Get the project north
    project_north = None
    for rel in ifc_file.by_type('IfcRelAggregates'):
    if rel.RelatingObject.is_a('IfcProject') and rel.RelatedObjects:
    for obj in rel.RelatedObjects:
    if obj.is_a('IfcSite'):
    project_north = obj.ObjectPlacement.RelativePlacement.RefDirection

    return {
    "latitude": latitude,
    "longitude": longitude,
    "elevation": elevation,
    "project_north": project_north
    }

    geo_file1 = get_geolocation(ifc_file1)
    geo_file2 = get_geolocation(ifc_file2)

    geo_file1, geo_file2

    after that my linked model properly align in my opened model.

    thank you moult :D

    steverugi
  • Uh, that code actually doesn't make much sense and doesn't help isolate exactly what the issue is / was.

  • i dont know, but it's exactly same version with no update before i run this code.
    all i can think its because the units difference, the building one using milimeter unit which the coordinate decimal digit area bigger than site files which is using meter units. maybe the improper rotation before was because a slight difference in milimeter numbers, not because some blenderbim error.
    i don't know, i'm the beginner here, maybe you have any idea about this problem.

  • I'll need to actually see your (original) files to be able to figure out what's going on. Can we screenshare or can you share the files (privately to [email protected])?

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