U-Splines generated in Coreform Cubit are saved along with the associated Cubit model as part of Cubit’s native HDF5 .cub5 file. The saved U-spline model state can then be re-opened in U-spline-enabled versions of Cubit.
U-Spline data can be saved only to .cub5 files in the Cubit HDF5 file format. If a U-spline model is saved to a non-HDF5 format, the U-spline data will not be saved, and will be lost when the session is reset or closed.
Cubit .cub5 files containing U-splines can be opened in versions of Cubit (such as Sandia Cubit) that do not include U-spline functionality, but U-spline data will be ignored.
The U-spline data saved to an HDF5 .cub5 file includes both a history of Coreform IGA commands and periodic snapshots of the U-spline output.
A sequential history of IGA commands is automatically saved to the .cub5 file when a U-spline is saved. This provides a history of the model and supplies groundwork for future development of advanced features like undo/redo and version control.
For efficiency, Cubit also saves periodic snapshots of the current state of the U-spline model, consisting of the JSON export data for the model at the time of snapshot.
When a U-spline .cub5 file is opened, the U-spline model data is populated by the most recent snapshot, after which any subsequent history commands are re-executed.