Cannot open NASA .glb files: KeyError: 'bufferView'

[weberm@…]

The following bug report has been submitted:
Platform:        Windows-10-10.0.26100
ChimeraX Version: 1.10.1 (2025-07-24 20:15:27 UTC)
Description
Was trying to use ChimeraX to load several official NASA .glb files - all failed. Question is whether this is a general issue with ChimeaX not properly recognizing / interpreting .glb files?

Log:
UCSF ChimeraX version: 1.10.1 (2025-07-24)  
© 2016-2025 Regents of the University of California. All rights reserved.  
How to cite UCSF ChimeraX  

> open "C:\\\Users\\\PCUser\\\Desktop\\\HoloDeck\\\NASA_data\\\Mars 2020
> Perseverance Rover.glb"

Summary of feedback from opening
C:\\\Users\\\PCUser\\\Desktop\\\HoloDeck\\\NASA_data\\\Mars 2020 Perseverance
Rover.glb  
---  
warnings | glTF node 0 has unsupported rotation, scale or translation, ignoring it  
glTF node 1 has unsupported rotation, scale or translation, ignoring it  
glTF node 2 has unsupported rotation, scale or translation, ignoring it  
glTF node 3 has unsupported rotation, scale or translation, ignoring it  
glTF node 4 has unsupported rotation, scale or translation, ignoring it  
82 messages similar to the above omitted  
  
Traceback (most recent call last):  
File "C:\Program Files\ChimeraX 1.10.1\bin\Lib\site-
packages\chimerax\core\\__main__.py", line 1016, in init  
commands.run(sess, "open %s" % StringArg.unparse(arg))  
File "C:\Program Files\ChimeraX 1.10.1\bin\Lib\site-
packages\chimerax\core\commands\run.py", line 49, in run  
results = command.run(text, log=log, return_json=return_json)  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File "C:\Program Files\ChimeraX 1.10.1\bin\Lib\site-
packages\chimerax\core\commands\cli.py", line 3221, in run  
result = ci.function(session, **kw_args)  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File "C:\Program Files\ChimeraX 1.10.1\bin\Lib\site-
packages\chimerax\open_command\cmd.py", line 132, in cmd_open  
models = Command(session, registry=registry).run(provider_cmd_text,
log=log)[0]  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File "C:\Program Files\ChimeraX 1.10.1\bin\Lib\site-
packages\chimerax\core\commands\cli.py", line 3221, in run  
result = ci.function(session, **kw_args)  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File "C:\Program Files\ChimeraX 1.10.1\bin\Lib\site-
packages\chimerax\open_command\cmd.py", line 215, in provider_open  
models, status = collated_open(session, None, [data], data_format,
_add_models,  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File "C:\Program Files\ChimeraX 1.10.1\bin\Lib\site-
packages\chimerax\open_command\cmd.py", line 526, in collated_open  
return remember_data_format()  
^^^^^^^^^^^^^^^^^^^^^^  
File "C:\Program Files\ChimeraX 1.10.1\bin\Lib\site-
packages\chimerax\open_command\cmd.py", line 497, in remember_data_format  
models, status = func(*func_args, **func_kw)  
^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File "C:\Program Files\ChimeraX 1.10.1\bin\Lib\site-
packages\chimerax\gltf\\__init__.py", line 46, in open  
return gltf.read_gltf(session, data, file_name)  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File "C:\Program Files\ChimeraX 1.10.1\bin\Lib\site-
packages\chimerax\gltf\gltf.py", line 91, in read_gltf  
ba = buffer_arrays(j['accessors'], bv, bin_chunk)  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File "C:\Program Files\ChimeraX 1.10.1\bin\Lib\site-
packages\chimerax\gltf\gltf.py", line 302, in buffer_arrays  
ibv = a['bufferView'] # index into buffer_views  
~^^^^^^^^^^^^^^  
KeyError: 'bufferView'  
  
KeyError: 'bufferView'  
  
File "C:\Program Files\ChimeraX 1.10.1\bin\Lib\site-
packages\chimerax\gltf\gltf.py", line 302, in buffer_arrays  
ibv = a['bufferView'] # index into buffer_views  
~^^^^^^^^^^^^^^  
  
See log for complete Python traceback.  
  




OpenGL version: 3.3.0 Core Profile Context 23.19.21.11.250530
OpenGL renderer: AMD Radeon(TM) Graphics
OpenGL vendor: ATI Technologies Inc.

Python: 3.11.4
Locale: de_DE.cp1252
Qt version: PyQt6 6.8.1, Qt 6.8.2
Qt runtime version: 6.8.2
Qt platform: windows

Manufacturer: LENOVO
Model: 20UES3YA01
OS: Microsoft Windows 11 Pro (Build 26100)
Memory: 33,528,926,208
MaxProcessMemory: 137,438,953,344
CPU: 16 AMD Ryzen 7 PRO 4750U with Radeon Graphics
OSLanguage: de-DE

Installed Packages:
    alabaster: 1.0.0
    appdirs: 1.4.4
    asttokens: 3.0.0
    babel: 2.17.0
    beautifulsoup4: 4.13.3
    blockdiag: 3.0.0
    blosc2: 3.6.1
    build: 1.2.2.post1
    certifi: 2025.7.14
    cftime: 1.6.4.post1
    charset-normalizer: 3.4.2
    ChimeraX-AddCharge: 1.5.19
    ChimeraX-AddH: 2.2.7
    ChimeraX-AlignmentAlgorithms: 2.0.2
    ChimeraX-AlignmentHdrs: 3.6.1
    ChimeraX-AlignmentMatrices: 2.1
    ChimeraX-Alignments: 2.20.2
    ChimeraX-AlphaFold: 1.0.1
    ChimeraX-AltlocExplorer: 1.1.2
    ChimeraX-AmberInfo: 1.0
    ChimeraX-Aniso: 1.1.4
    ChimeraX-Arrays: 1.1
    ChimeraX-Atomic: 1.60.7
    ChimeraX-AtomicLibrary: 14.1.19
    ChimeraX-AtomSearch: 2.0.1
    ChimeraX-AxesPlanes: 2.4
    ChimeraX-BasicActions: 1.1.3
    ChimeraX-BILD: 1.0
    ChimeraX-BlastProtein: 3.0.0
    ChimeraX-Boltz: 1.0
    ChimeraX-BondRot: 2.0.4
    ChimeraX-BugReporter: 1.0.2
    ChimeraX-BuildStructure: 2.13.1
    ChimeraX-Bumps: 1.0
    ChimeraX-BundleBuilder: 1.5.1
    ChimeraX-ButtonPanel: 1.0.1
    ChimeraX-CageBuilder: 1.0.1
    ChimeraX-CellPack: 1.0
    ChimeraX-Centroids: 1.4
    ChimeraX-ChangeChains: 1.1
    ChimeraX-CheckWaters: 1.5
    ChimeraX-ChemGroup: 2.0.2
    ChimeraX-Clashes: 2.3
    ChimeraX-ColorActions: 1.0.5
    ChimeraX-ColorGlobe: 1.0
    ChimeraX-ColorKey: 1.5.8
    ChimeraX-CommandLine: 1.3
    ChimeraX-ConnectStructure: 2.0.1
    ChimeraX-Contacts: 1.0.1
    ChimeraX-Core: 1.10.1
    ChimeraX-CoreFormats: 1.2
    ChimeraX-coulombic: 1.4.5
    ChimeraX-Crosslinks: 1.0
    ChimeraX-Crystal: 1.0
    ChimeraX-CrystalContacts: 1.0.1
    ChimeraX-DataFormats: 1.2.4
    ChimeraX-Dicom: 1.2.7
    ChimeraX-DistMonitor: 1.4.2
    ChimeraX-DockPrep: 1.1.4
    ChimeraX-Dssp: 2.0
    ChimeraX-EMDB-SFF: 1.0
    ChimeraX-ESMFold: 1.0
    ChimeraX-FileHistory: 1.0.1
    ChimeraX-FunctionKey: 1.0.1
    ChimeraX-Geometry: 1.3
    ChimeraX-gltf: 1.0
    ChimeraX-Graphics: 1.4.1
    ChimeraX-Hbonds: 2.5.1
    ChimeraX-Help: 1.3
    ChimeraX-HKCage: 1.3
    ChimeraX-IHM: 1.1
    ChimeraX-ImageFormats: 1.2
    ChimeraX-IMOD: 1.0
    ChimeraX-IO: 1.0.3
    ChimeraX-ItemsInspection: 1.0.1
    ChimeraX-IUPAC: 1.0
    ChimeraX-KVFinder: 1.6.2
    ChimeraX-Label: 1.1.14
    ChimeraX-ListInfo: 1.2.2
    ChimeraX-Log: 1.2
    ChimeraX-LookingGlass: 1.1
    ChimeraX-Maestro: 1.9.1
    ChimeraX-Map: 1.3
    ChimeraX-MapData: 2.0
    ChimeraX-MapEraser: 1.0.1
    ChimeraX-MapFilter: 2.0.1
    ChimeraX-MapFit: 2.0
    ChimeraX-MapSeries: 2.1.1
    ChimeraX-Markers: 1.0.1
    ChimeraX-Mask: 1.0.2
    ChimeraX-MatchMaker: 2.2.2
    ChimeraX-MCopy: 1.0
    ChimeraX-MDcrds: 2.10.1
    ChimeraX-MedicalToolbar: 1.1
    ChimeraX-Meeting: 1.0.1
    ChimeraX-MLP: 1.1.1
    ChimeraX-mmCIF: 2.16
    ChimeraX-MMTF: 2.2
    ChimeraX-ModelArchive: 1.0
    ChimeraX-Modeller: 1.5.19
    ChimeraX-ModelPanel: 1.5.1
    ChimeraX-ModelSeries: 1.0.1
    ChimeraX-Mol2: 2.0.3
    ChimeraX-Mole: 1.0
    ChimeraX-Morph: 1.0.2
    ChimeraX-MouseModes: 1.2
    ChimeraX-Movie: 1.0
    ChimeraX-MutationScores: 1.0
    ChimeraX-Neuron: 1.0
    ChimeraX-Nifti: 1.2
    ChimeraX-NMRSTAR: 1.0.2
    ChimeraX-NRRD: 1.2
    ChimeraX-Nucleotides: 2.0.3
    ChimeraX-OpenCommand: 1.14.1
    ChimeraX-OrthoPick: 1.0.1
    ChimeraX-PDB: 2.7.10
    ChimeraX-PDBBio: 1.0.1
    ChimeraX-PDBLibrary: 1.0.4
    ChimeraX-PDBMatrices: 1.0
    ChimeraX-PickBlobs: 1.0.1
    ChimeraX-Positions: 1.0
    ChimeraX-PresetMgr: 1.1.3
    ChimeraX-ProfileGrids: 1.1.3
    ChimeraX-PubChem: 2.2
    ChimeraX-ReadPbonds: 1.0.1
    ChimeraX-Registration: 1.1.2
    ChimeraX-RemoteControl: 1.0
    ChimeraX-RenderByAttr: 1.6.3
    ChimeraX-RenumberResidues: 1.1
    ChimeraX-ResidueFit: 1.0.1
    ChimeraX-RestServer: 1.3.1
    ChimeraX-RNALayout: 1.0
    ChimeraX-RotamerLibMgr: 4.0
    ChimeraX-RotamerLibsDunbrack: 2.0
    ChimeraX-RotamerLibsDynameomics: 2.0
    ChimeraX-RotamerLibsRichardson: 2.0
    ChimeraX-SaveCommand: 1.5.1
    ChimeraX-SchemeMgr: 1.0
    ChimeraX-SDF: 2.0.3
    ChimeraX-Segger: 1.0
    ChimeraX-Segment: 1.0.1
    ChimeraX-Segmentations: 3.5.7
    ChimeraX-SelInspector: 1.0
    ChimeraX-SeqView: 2.17.1
    ChimeraX-Shape: 1.1
    ChimeraX-Shell: 1.0.1
    ChimeraX-Shortcuts: 1.2.1
    ChimeraX-ShowSequences: 1.0.3
    ChimeraX-SideView: 1.0.1
    ChimeraX-SimilarStructures: 1.0.1
    ChimeraX-Smiles: 2.1.2
    ChimeraX-SmoothLines: 1.0
    ChimeraX-SpaceNavigator: 1.0
    ChimeraX-StdCommands: 1.19.1
    ChimeraX-STL: 1.0.1
    ChimeraX-Storm: 1.0
    ChimeraX-StructMeasure: 1.2.1
    ChimeraX-Struts: 1.0.1
    ChimeraX-Surface: 1.0.1
    ChimeraX-SwapAA: 2.0.1
    ChimeraX-SwapRes: 2.5.2
    ChimeraX-TapeMeasure: 1.0
    ChimeraX-TaskManager: 1.0
    ChimeraX-Test: 1.0
    ChimeraX-Toolbar: 1.2.3
    ChimeraX-ToolshedUtils: 1.2.4
    ChimeraX-Topography: 1.0
    ChimeraX-ToQuest: 1.0
    ChimeraX-Tug: 1.0.1
    ChimeraX-UI: 1.45.2
    ChimeraX-Umap: 1.0
    ChimeraX-uniprot: 2.3.1
    ChimeraX-UnitCell: 1.0.1
    ChimeraX-ViewDockX: 1.4.4
    ChimeraX-VIPERdb: 1.0
    ChimeraX-Vive: 1.1
    ChimeraX-VolumeMenu: 1.0.1
    ChimeraX-vrml: 1.0
    ChimeraX-VTK: 1.0
    ChimeraX-WavefrontOBJ: 1.0
    ChimeraX-WebCam: 1.0.2
    ChimeraX-WebServices: 1.1.5
    ChimeraX-Zone: 1.0.1
    colorama: 0.4.6
    comm: 0.2.2
    comtypes: 1.4.10
    contourpy: 1.3.2
    coverage: 7.10.0
    cxservices: 1.2.3
    cycler: 0.12.1
    Cython: 3.0.12
    debugpy: 1.8.15
    decorator: 5.2.1
    docutils: 0.21.2
    executing: 2.2.0
    filelock: 3.18.0
    fonttools: 4.59.0
    funcparserlib: 2.0.0a0
    glfw: 2.9.0
    grako: 3.16.5
    h5py: 3.14.0
    html2text: 2024.2.26
    idna: 3.10
    ihm: 2.2
    imagecodecs: 2024.6.1
    imagesize: 1.4.1
    iniconfig: 2.1.0
    ipykernel: 6.29.5
    ipython: 8.26.0
    ipywidgets: 8.1.7
    jedi: 0.19.1
    Jinja2: 3.1.6
    jupyter_client: 8.6.3
    jupyter_core: 5.8.1
    jupyterlab_widgets: 3.0.15
    kiwisolver: 1.4.8
    line_profiler: 4.2.0
    lxml: 5.3.1
    lz4: 4.3.2
    MarkupSafe: 3.0.2
    matplotlib: 3.10.1
    matplotlib-inline: 0.1.7
    MolecularDynamicsViewer: 1.6
    msgpack: 1.1.0
    ndindex: 1.10.0
    nest-asyncio: 1.6.0
    netCDF4: 1.6.5
    networkx: 3.3
    nibabel: 5.2.0
    nptyping: 2.5.0
    numexpr: 2.11.0
    numpy: 1.26.4
    nvidia-nvjitlink-cu12: 12.9.86
    OpenMM: 8.2.0
    OpenMM-CUDA-12: 8.2.0
    openvr: 1.26.701
    packaging: 24.2
    ParmEd: 4.2.2
    parso: 0.8.4
    pep517: 0.13.1
    pickleshare: 0.7.5
    pillow: 10.4.0
    pip: 25.0.1
    pkginfo: 1.11.1
    platformdirs: 4.3.8
    pluggy: 1.6.0
    prompt_toolkit: 3.0.51
    psutil: 7.0.0
    pure_eval: 0.2.3
    py-cpuinfo: 9.0.0
    pycollada: 0.8
    pydicom: 2.4.4
    Pygments: 2.18.0
    pynmrstar: 3.3.5
    pynrrd: 1.0.0
    PyOpenGL: 3.1.9
    PyOpenGL-accelerate: 3.1.9
    pyopenxr: 1.1.4501
    pyparsing: 3.2.3
    pyproject_hooks: 1.2.0
    PyQt6-commercial: 6.8.1
    PyQt6-Qt6: 6.8.2
    PyQt6-WebEngine-commercial: 6.8.0
    PyQt6-WebEngine-Qt6: 6.8.2
    PyQt6_sip: 13.10.0
    pytest: 8.4.1
    pytest-cov: 6.2.1
    python-dateutil: 2.9.0.post0
    pytz: 2025.2
    pywin32: 310
    pyzmq: 27.0.0
    qtconsole: 5.5.2
    QtPy: 2.4.3
    qtshim: 1.1
    RandomWords: 0.4.0
    requests: 2.32.3
    roman-numerals-py: 3.1.0
    scipy: 1.14.0
    setuptools: 78.1.0
    sfftk-rw: 0.8.1
    six: 1.16.0
    snowballstemmer: 3.0.1
    sortedcontainers: 2.4.0
    soupsieve: 2.7
    Sphinx: 8.2.3
    sphinx-autodoc-typehints: 3.1.0
    sphinxcontrib-applehelp: 2.0.0
    sphinxcontrib-blockdiag: 3.0.0
    sphinxcontrib-devhelp: 2.0.0
    sphinxcontrib-htmlhelp: 2.1.0
    sphinxcontrib-jsmath: 1.0.1
    sphinxcontrib-qthelp: 2.0.0
    sphinxcontrib-serializinghtml: 2.0.0
    stack-data: 0.6.3
    superqt: 0.7.1
    tables: 3.10.2
    tcia_utils: 1.5.1
    tifffile: 2025.3.13
    tinyarray: 1.2.4
    tornado: 6.5.1
    traitlets: 5.14.3
    typing_extensions: 4.14.1
    tzdata: 2025.2
    urllib3: 2.5.0
    wcwidth: 0.2.13
    webcolors: 24.11.1
    wheel: 0.45.1
    wheel-filename: 1.4.2
    widgetsnbextension: 4.0.14
    WMI: 1.5.1
File attachment: Mars 2020 Perseverance Rover.glb

Mars 2020 Perseverance Rover.glb​

[weberm@…]

Added by email2trac

[Eric Pettersen]

Reported by Michael Weber

[Tom Goddard]

The ChimeraX GLTF reader does not handle every aspect of the GLTF specification. In particular the attached NASA rover model uses a GLTF extension called KHR_draco_mesh_compression which represents triangular meshes in a much more compact way so the .glb files are smaller. ChimeraX cannot handle that. It only handles having the triangles and vertices in uncompressed format. That is why the error is about a missing "bufferView". The bufferView is the array with those coordinates that is not present because the KHR_draco_mesh_compression extension fills in the coordinates. Here's the web site I used to see that the .glb file is using this extension:

​https://gltf.report