SceneAnimation class goes into session files even when scenes and animations not used

[goddard@…]

The following bug report has been submitted:
Platform:        macOS-26.5.2-arm64-arm-64bit
ChimeraX Version: 1.11.1 (2026-01-23 05:51:34 UTC)
Description
Tried to open a session saved in ChimeraX daily build containing only two maps in older ChimeraX 1.11.1 and it failed due to missing SceneAnimation.  Why is anything involving SceneAnimation going into the session when I did not use any scenes or animations?  

Log:
Startup Messages  
---  
note | CubeNTube: sphere eraser undo support enabled  
  
UCSF ChimeraX version: 1.11.1 (2026-01-23)  
© 2016-2025 Regents of the University of California. All rights reserved.  
How to cite UCSF ChimeraX  

> open /Users/goddard/ucsf/chimerax/src/bundles/map/test2.cxs format session

Opened emdb 1080 as #1, grid size 100,100,100, pixel 2.7, shown at level
0.852, step 1, values float32  
Opened emdb 1080 gaussian as #2, grid size 100,100,100, pixel 2.7, shown at
level 1.67, step 1, values float32  
Unable to restore session, resetting.  
  
Traceback (most recent call last):  
File
"/Users/goddard/ucsf/old_chimerax/ChimeraX-1.11.1.app/Contents/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-
packages/chimerax/core/session.py", line 847, in restore  
cls = name.class_of(self)  
^^^^^^^^^^^^^^^^^^^  
File
"/Users/goddard/ucsf/old_chimerax/ChimeraX-1.11.1.app/Contents/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-
packages/chimerax/core/session.py", line 228, in class_of  
cls = bundle_info.get_class(class_name, session.logger)  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File
"/Users/goddard/ucsf/old_chimerax/ChimeraX-1.11.1.app/Contents/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-
packages/chimerax/core/toolshed/info.py", line 487, in get_class  
return f(class_name)  
^^^^^^^^^^^^^  
File
"/Users/goddard/ucsf/old_chimerax/ChimeraX-1.11.1.app/Contents/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-
packages/chimerax/animations/__init__.py", line 24, in get_class  
raise ValueError("Unknown class name '%s'" % class_name)  
ValueError: Unknown class name 'SceneAnimation'  
  

> view name session-start

opened ChimeraX session  




OpenGL version: 4.1 Metal - 90.5
OpenGL renderer: Apple M2 Ultra
OpenGL vendor: Apple

Python: 3.11.9
Locale: en_US.UTF-8
Qt version: PyQt6 6.9.1, Qt 6.9.0
Qt runtime version: 6.9.2
Qt platform: cocoa
Hardware:

    Hardware Overview:

      Model Name: Mac Studio
      Model Identifier: Mac14,14
      Model Number: Z1800003VLL/A
      Chip: Apple M2 Ultra
      Total Number of Cores: 24 (16 Performance and 8 Efficiency)
      Memory: 64 GB
      System Firmware Version: 18000.121.3
      OS Loader Version: 18000.121.3

Software:

    System Software Overview:

      System Version: macOS 26.5.2 (25F84)
      Kernel Version: Darwin 25.5.0
      Time since boot: 18 hours, 57 minutes

Graphics/Displays:

    Apple M2 Ultra:

      Chipset Model: Apple M2 Ultra
      Type: GPU
      Bus: Built-In
      Total Number of Cores: 60
      Vendor: Apple (0x106b)
      Metal Support: Metal 4
      Displays:
        PHL 278B1:
          Resolution: 3840 x 2160 (2160p/4K UHD 1 - Ultra High Definition)
          UI Looks like: 1920 x 1080 @ 60.00Hz
          Main Display: Yes
          Mirror: Off
          Online: Yes
          Rotation: Supported


Installed Packages:
    aiohappyeyeballs: 2.6.1
    aiohttp: 3.13.1
    aiosignal: 1.4.0
    alabaster: 1.0.0
    annotated-types: 0.7.0
    anyio: 4.12.1
    appdirs: 1.4.4
    appnope: 0.1.4
    asttokens: 3.0.1
    attrs: 25.4.0
    babel: 2.17.0
    beautifulsoup4: 4.13.5
    blockdiag: 3.0.0
    blosc2: 3.12.2
    build: 1.3.0
    certifi: 2025.7.14
    cftime: 1.6.5
    charset-normalizer: 3.4.4
    ChimeraX-AddCharge: 1.5.20
    ChimeraX-AddH: 2.2.8
    ChimeraX-AlignmentAlgorithms: 2.0.2
    ChimeraX-AlignmentHdrs: 3.6.1
    ChimeraX-AlignmentMatrices: 2.1
    ChimeraX-Alignments: 3.1.1
    ChimeraX-AlphaFold: 1.0.1
    ChimeraX-AltlocExplorer: 1.2
    ChimeraX-AmberInfo: 1.0
    ChimeraX-Animations: 1.0
    ChimeraX-Aniso: 1.3.2
    ChimeraX-Arrays: 1.1
    ChimeraX-Atomic: 1.61.4
    ChimeraX-AtomicLibrary: 14.2.1
    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: 1.1
    ChimeraX-BondRot: 2.0.4
    ChimeraX-BugReporter: 1.0.2
    ChimeraX-BuildStructure: 2.13.1
    ChimeraX-Bumps: 1.0
    ChimeraX-BundleBuilder: 1.6.0
    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-ChopChopMF: 1.0
    ChimeraX-Clashes: 2.3
    ChimeraX-clix: 0.2.4
    ChimeraX-ColorActions: 1.0.5
    ChimeraX-ColorGlobe: 1.0
    ChimeraX-ColorKey: 1.5.8
    ChimeraX-CommandLine: 1.3.0
    ChimeraX-ConnectStructure: 2.0.1
    ChimeraX-Contacts: 1.0.1
    ChimeraX-Core: 1.11.1
    ChimeraX-CoreFormats: 1.2
    ChimeraX-coulombic: 1.4.5
    ChimeraX-Crosslinks: 1.0
    ChimeraX-Crystal: 1.0
    ChimeraX-CrystalContacts: 1.0.1
    ChimeraX-CubeNTube: 0.1.0
    ChimeraX-DAQplugin: 0.12.0
    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: 2.5.3
    ChimeraX-Help: 1.3
    ChimeraX-HKCage: 1.3
    ChimeraX-IHM: 1.1
    ChimeraX-ImageFormats: 1.2
    ChimeraX-IMOD: 1.0
    ChimeraX-IO: 1.0.4
    ChimeraX-ItemsInspection: 1.0.1
    ChimeraX-IUPAC: 1.0
    ChimeraX-KVFinder: 1.7.3
    ChimeraX-Label: 1.2
    ChimeraX-ListInfo: 1.2.2
    ChimeraX-Log: 1.2.2
    ChimeraX-LookingGlass: 1.1
    ChimeraX-Maestro: 1.9.2
    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-MCPServer: 0.1.0
    ChimeraX-MDcrds: 2.17.2
    ChimeraX-MedicalToolbar: 1.1
    ChimeraX-Meeting: 1.0.1
    ChimeraX-Minimize: 1.3.2
    ChimeraX-MLP: 1.1.1
    ChimeraX-mmCIF: 2.16
    ChimeraX-MMTF: 2.2
    ChimeraX-ModelArchive: 1.0
    ChimeraX-Modeller: 1.5.22
    ChimeraX-ModelPanel: 1.6
    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: 1.0.1
    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: 1.15.2
    ChimeraX-OrthoPick: 1.0.1
    ChimeraX-PDB: 2.7.12
    ChimeraX-PDBBio: 1.0.1
    ChimeraX-PDBLibrary: 1.0.5
    ChimeraX-PDBMatrices: 1.0
    ChimeraX-PhenixUI: 1.3.9
    ChimeraX-PickBlobs: 1.0.1
    ChimeraX-Positions: 1.0
    ChimeraX-PresetMgr: 1.1.4
    ChimeraX-ProfileGrids: 1.4.2
    ChimeraX-PubChem: 2.2
    ChimeraX-ReadPbonds: 1.0.1
    ChimeraX-Registration: 1.1.2
    ChimeraX-RemoteControl: 1.0
    ChimeraX-RenderByAttr: 1.6.5
    ChimeraX-RenumberResidues: 1.1
    ChimeraX-ResidueFit: 1.0.1
    ChimeraX-RestServer: 1.3.3
    ChimeraX-RNALayout: 1.0
    ChimeraX-RotamerLibMgr: 4.0
    ChimeraX-RotamerLibsDunbrack: 2.0
    ChimeraX-RotamerLibsDynameomics: 2.0
    ChimeraX-RotamerLibsRichardson: 2.0
    ChimeraX-SaveCommand: 1.5.2
    ChimeraX-Scenes: 0.3.1
    ChimeraX-SchemeMgr: 1.0
    ChimeraX-SDF: 2.0.3
    ChimeraX-Segger: 1.0
    ChimeraX-Segment: 1.0.1
    ChimeraX-Segmentations: 3.5.10
    ChimeraX-SelInspector: 1.0
    ChimeraX-SeqView: 2.17.3
    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-TutorialReadFormat: 0.1
    ChimeraX-UI: 1.49.1
    ChimeraX-Umap: 1.0
    ChimeraX-uniprot: 2.3.2
    ChimeraX-UnitCell: 1.0.1
    ChimeraX-ViewDock: 1.5.2
    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
    click: 8.3.1
    colorama: 0.4.6
    coloredlogs: 15.0.1
    comm: 0.2.3
    contourpy: 1.3.3
    coverage: 7.13.1
    cxservices: 1.2.3
    cycler: 0.12.1
    Cython: 3.1.4
    debugpy: 1.8.19
    decorator: 5.2.1
    docutils: 0.21.2
    executing: 2.2.1
    filelock: 3.19.1
    flatbuffers: 25.12.19
    fonttools: 4.61.1
    frozenlist: 1.8.0
    funcparserlib: 2.0.0a0
    glfw: 2.10.0
    grako: 3.16.5
    h11: 0.16.0
    h5py: 3.15.1
    html2text: 2025.4.15
    httpcore: 1.0.9
    httpx: 0.28.1
    httpx-sse: 0.4.3
    humanfriendly: 10.0
    idna: 3.11
    ihm: 2.2
    imagecodecs: 2024.6.1
    imagesize: 1.4.1
    iniconfig: 2.3.0
    ipykernel: 6.30.1
    ipython: 9.5.0
    ipython_pygments_lexers: 1.1.1
    ipywidgets: 8.1.8
    jedi: 0.19.2
    Jinja2: 3.1.6
    joblib: 1.5.0
    jsonschema: 4.26.0
    jsonschema-specifications: 2025.9.1
    jupyter_client: 8.6.3
    jupyter_core: 5.9.1
    jupyterlab_widgets: 3.0.16
    kiwisolver: 1.4.9
    line_profiler: 5.0.0
    llvmlite: 0.44.0
    lxml: 6.0.2
    lz4: 4.3.2
    Markdown: 3.8.2
    MarkupSafe: 3.0.3
    matplotlib: 3.10.7
    matplotlib-inline: 0.2.1
    mcp: 1.18.0
    mpmath: 1.3.0
    mrcfile: 1.5.4
    msgpack: 1.1.1
    multidict: 6.7.0
    narwhals: 2.6.0
    ndindex: 1.10.1
    nest-asyncio: 1.6.0
    netCDF4: 1.6.5
    networkx: 3.3
    nibabel: 5.2.0
    nptyping: 2.5.0
    numba: 0.61.2
    numexpr: 2.14.1
    numpy: 2.2.6
    numpy: 1.26.4
    onnxruntime: 1.23.2
    OpenMM: 8.2.0
    openvr: 1.26.701
    packaging: 25.0
    pandas: 2.3.3
    ParmEd: 4.2.2
    parso: 0.8.5
    pep517: 0.13.1
    pexpect: 4.9.0
    pickleshare: 0.7.5
    pillow: 11.3.0
    pip: 25.2
    pkginfo: 1.12.1.2
    platformdirs: 4.5.1
    plotly: 6.3.1
    pluggy: 1.6.0
    prompt_toolkit: 3.0.52
    propcache: 0.4.1
    protobuf: 6.33.4
    psutil: 7.0.0
    ptyprocess: 0.7.0
    pure_eval: 0.2.3
    py-cpuinfo: 9.0.0
    pybind11: 3.0.1
    pycollada: 0.8
    pydantic: 2.12.5
    pydantic-settings: 2.12.0
    pydantic_core: 2.41.5
    pydicom: 2.4.4
    Pygments: 2.18.0
    pyKVFinder: 0.8.3
    pynmrstar: 3.3.6
    pynndescent: 0.5.13
    pynrrd: 1.0.0
    PyOpenGL: 3.1.10
    PyOpenGL-accelerate: 3.1.10
    pyopenxr: 1.1.4501
    pyparsing: 3.3.2
    pyproject_hooks: 1.2.0
    PyQt5: 5.15.11
    PyQt5-Qt5: 5.15.18
    PyQt5_sip: 12.17.1
    PyQt6-commercial: 6.9.1
    PyQt6-Qt6: 6.9.2
    PyQt6-WebEngine-commercial: 6.9.0
    PyQt6-WebEngine-Qt6: 6.9.2
    PyQt6_sip: 13.10.2
    pytest: 9.0.2
    pytest-cov: 7.0.0
    python-dateutil: 2.9.0.post0
    python-dotenv: 1.2.1
    python-multipart: 0.0.21
    pyzmq: 27.1.0
    qtconsole: 5.7.0
    QtPy: 2.4.3
    qtshim: 1.2
    RandomWords: 0.4.0
    referencing: 0.37.0
    requests: 2.32.5
    roman-numerals: 4.1.0
    roman-numerals-py: 4.1.0
    rpds-py: 0.30.0
    scikit-learn: 1.6.1
    scipy: 1.14.0
    Send2Trash: 1.8.3
    setuptools: 80.9.0
    sfftk-rw: 0.8.1
    six: 1.17.0
    snowballstemmer: 3.0.1
    sortedcontainers: 2.4.0
    soupsieve: 2.8.3
    Sphinx: 8.2.3
    sphinx-autodoc-typehints: 3.2.0
    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
    sse-starlette: 3.2.0
    stack-data: 0.6.3
    starlette: 0.52.1
    superqt: 0.7.6
    sympy: 1.14.0
    tables: 3.10.2
    tcia_utils: 1.5.1
    threadpoolctl: 3.6.0
    tifffile: 2025.3.13
    tinyarray: 1.2.5
    tomlkit: 0.13.3
    tornado: 6.5.4
    tqdm: 4.67.1
    traitlets: 5.14.3
    typing-inspection: 0.4.2
    typing_extensions: 4.15.0
    umap-learn: 0.5.7
    urllib3: 2.6.3
    uvicorn: 0.40.0
    wcwidth: 0.3.2
    webcolors: 24.11.1
    wheel: 0.45.1
    wheel-filename: 1.4.2
    widgetsnbextension: 4.0.15
    yarl: 1.22.0

[Tom Goddard]

Session saved after just opening a map in ChimeraX 1.12 fails to open in 1.11.1.