# mesh-diagnostics v3.2.3

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

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## Description

`mesh-diagnostics` is a tool designed to **print the characteristics of an input mesh** and perform additional diagnostic operations such as disassembly, center-line generation, and mesh quality checks.

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## Usage

```bash
mesh-diagnostics [OPTIONS] -m input
```

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## Options

### **General Options**


| Option         | Description                          |
| -------------- | ------------------------------------ |
| `--help`, `-h` | Display help and exit.               |
| `-m <file>`    | **Required.** Mesh file to diagnose. |


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### **Diagnostic Options**


| Option          | Description                                                                                 |
| --------------- | ------------------------------------------------------------------------------------------- |
| `--debug`       | Activate verbose debug mode for `--disassembly`.                                            |
| `--disassembly` | Split the mesh into a **polygon file** (boundary) and a **node file**.                      |
| `--center-line` | Generate 3 additional meshes from nodes using different cleaning methods.                   |
| `-r <rootname>` | Root name for output files when using `--disassembly` or `--center-line`. Default is empty. |


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### **Deprecated Options**

> **Note:** These options are **no longer recommended** and may be removed in future versions.


| Option             | Description                                           |
| ------------------ | ----------------------------------------------------- |
| `--no_renum`       | Disable mesh renumbering.                             |
| `--no_reshape`     | Disable mesh reshaping.                               |
| `--delaunay`       | Use Delaunay triangulation.                           |
| `--nghmax <value>` | Set maximum number of neighbors.                      |
| `-c`               | Check channels.                                       |
| `-d <resolution>`  | Maximum resolution for refinement.                    |
| `-g`               | Check geometry.                                       |
| `-p <polygon>`     | Limit actions to the interior of a specified polygon. |
| `-o <path>`        | Output path for results.                              |
| `-s`               | Set safety mode.                                      |
| `-z <zone>`        | Limit actions to a specified rectangular zone.        |


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## Examples

### **Basic Mesh Diagnosis**

Print the characteristics of a mesh file:

```bash
mesh-diagnostics -m input_mesh.nc
```

### **Disassemble a Mesh**

Split a mesh into boundary and node files:

```bash
mesh-diagnostics -m input_mesh.nc --disassembly -r output_root
```

### **Generate Center-Line Meshes**

Generate 3 cleaned meshes from nodes:

```bash
mesh-diagnostics -m input_mesh.nc --center-line -r output_root
```

### **Debug Disassembly**

Enable verbose debug mode for disassembly:

```bash
mesh-diagnostics -m input_mesh.nc --disassembly --debug -r output_root
```

### **Check Mesh Geometry**

> **Note:** Uses deprecated option `-g` for backward compatibility.

```bash
mesh-diagnostics -m input_mesh.nc -g
```

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## Environment Variables

`mesh-diagnostics` does not use any specific environment variables. However, it may inherit standard system environment variables for file paths, permissions, and parallel processing (if applicable).

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## Notes

1. **Input Mesh:**
  - The input mesh file (`-m`) **must** be provided.
  - Supported formats: **TRIGRID** (default).
2. **Output Files:**
  - If `-r` is not specified, output files will use default names.
  - For `--disassembly`, two files are generated: one for the boundary (polygon) and one for the nodes.
  - For `--center-line`, three additional meshes are generated.
3. **Aspect Ratio:**
  - The tool automatically computes and displays the **aspect ratio** of each triangle in the mesh.
  - Triangles with an aspect ratio **&gt; 0.25** are flagged.
  - The worst aspect ratio and its location are reported.
4. **Deprecated Options:**
  - Deprecated options are **not recommended** for new workflows.
  - They are included for backward compatibility but may be removed in future versions.

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## See Also

- [TRIGRID Mesh Format](https://www.example.com) (Replace with actual documentation link if available)
- [Delaunay Triangulation](https://en.wikipedia.org/wiki/Delaunay_triangulation)
- [Mesh Quality Metrics](https://www.example.com) (Replace with actual documentation link if available)