# mesh-upgrade v3.2.3

**Mercurial revision 5786:5c8b45563631 | 2026-08-04**


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## Description
The `mesh-upgrade` tool refines, resamples, or subdivides edges of an existing mesh based on user-defined criteria. It is designed to improve mesh quality, handle polar regions, and ensure connectivity for unstructured ocean grids.

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## Usage
```bash
mesh-upgrade [OPTIONS] <meshfile> [-o <outputfile>] [-p <polyfile>] [-c <criteriafile>] [-m <maxrate>] [-d <dmax>] [-e <cmax>] [-z <zone>]
```

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## Options
| Option | Description |
|--------|-------------|
| `-h, --help` | Display this help message and exit. |
| `-m <file>` | Mesh file (.nei format). Use mesh-format to convert other grid format.  |
| `-p <polyfile>` | Polygon file use to limit the woking area (--subdivide) or rework the mesh edge (--exact, --limited) . |
| `-c <file>` | Criteria file for meshing rules. |
| `-o <file>` | Final output mesh file. Default: `mesh-upgrade.nei` |
| `--subdivide` | Subdivide rigid boundaries based on criteria. |
| `--resample` | Enable boundary resampling. |
| `--exact` | Deform original mesh to excatly fit the polygon in mesh splitting. |
| `--limited` | Limit the merge of splitted meshes to the boundary of the main one. |
| `--polar` | Enandle specific routines to handle polar grid. |
| `--debug` | Enable debug verbose mode.|

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## Examples
1. **Basic mesh refinement**:
   ```bash
   mesh-upgrade input_mesh.nei -o refined_mesh.nei
   ```

2. **Refine with custom criteria**:
   ```bash
   mesh-upgrade input_mesh.nei -c criteria.crt -o refined_mesh.nei
   ```

3. **Enable polar handling and debug mode**:
   ```bash
   mesh-upgrade input_mesh.nei --polar --debug -o polar_refined_mesh.nei
   ```

4. **Subdivide rigid boundaries**:
   ```bash
   mesh-upgrade input_mesh.nei --subdivide -p boundaries.plg -o subdivided_mesh.nei
   ```

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## Environment Variables
None.

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## Notes
- The tool requires a valid **mesh file** (`<meshfile>`) as input.
- If no output file is specified, the default output filename is `mesh-upgrade.nei`.
- The `--polar` option is essential for handling meshes in polar regions (e.g., Antarctic or Arctic).
- Debug mode (`--debug`) provides detailed logs for troubleshooting.

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## See Also
- [T-UGOm Documentation](https://t-ugom.example.com)
- [SIROCCO National Service](https://sirocco.example.com)
- [Mesh Generation Criteria](https://mesh-criteria.example.com)
```