Converting IFC to GLB using IfcConvert on Linux

[Vidyaranya Malladi]

While I am converting IFC to OBJ using c# pipeline it all works fine. but when I try to convert to GLB the file cannot be opened in any viewers, i ran GLB validator and it seems to always have issues like "GLB_CHUNK_LENGTH_UNALIGNED", "GLB_UNEXPECTED_FIRST_CHUNK" and others. When we do this conversion manually it works fine. I tried using additional options like --center-model-geometry. Still did not work. Any clues will be much appreciated.

[Thomas Krijnen]

Judging by the information you give us I'd be tempted to think it is related to binary vs text streams. If you open the outputs in text mode \r\n characters will get mapped to \n causing the chunks to no longer align. By random chance with binary floating pointing point numbers you're likely to have a couple of \r\n sequences.

[Vidyaranya Malladi]

@aothms, Thank you for your reply, I checked as you suggesed, I noticed only \n characters in the file.

[Vidyaranya Malladi]

Alternatively, I am trying to convert using ifcopenshell-python, but it seems to fail with errors. Here is the code.

fn = ifcopenshell.open(ifc_file)

ifcopenshell.ifcopenshell_wrapper.turn_off_detailed_logging()
ifcopenshell.ifcopenshell_wrapper.set_log_format_json()

settings = ifcopenshell.geom.settings(
    APPLY_DEFAULT_MATERIALS=True
)
settings.set(settings.USE_ELEMENT_GUIDS, True)
sr = ifcopenshell.geom.serializers.gltf(glb_file_name, settings)
sr.writeHeader()
for elem in ifcopenshell.geom.iterate(
    settings,
    file_or_filename=fn,
    with_progress=True,
    exclude=("IfcSpace", "IfcOpeningElement"),
    num_threads=1
):
    a = sr.write(elem)
sr.finalize()

Error:

NotImplementedError: Wrong number or type of arguments for overloaded function 'GltfSerializer_write'.
  Possible C/C++ prototypes are:
    GltfSerializer::write(IfcGeom::TriangulationElement const *)
    GltfSerializer::write(IfcGeom::BRepElement const *)

Please not converting to obj seems to work fine but we are looking for glb for optimization.

[Thomas Krijnen]

Because you've added:

with_progress=True

You get return a pair of progress as integer and the currently processed elem.

So either change to

with_progress=False

or to

for progress, elem in ifcopenshell.geom.iterate(