TETRA

TETRA is an open-source pipeline for exporting and importing volumetric tetrahedral meshes from Blender to Unity (or other engines), built on top of the tetrahedralization plugin by Matthias Müller – Ten Minute Physics.

This repository provides:

• A tetrahedralization plugin for Blender
• A .tetra file format exporter
• A Unity-compatible format and importer for use in simulations or visualization
• Format documentation and example meshes

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Features

• Generate volumetric tetrahedral meshes directly in Blender
• Export to .tetra: a clean, human-readable format
• Coordinate system conversion (Blender → Unity)
• Unity importer to load .tetra files as assets
• Easy integration with simulations, rendering, or analysis

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Getting Started

1. Clone the Repository

git clone https://github.com/marcobuttiglione/tetra.git

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2. Install Blender Add-ons

In Blender:

1. Open Edit > Preferences > Add-ons

2. Click Install...

3. Select the following files from the blender/ folder:

   • BlenderTetPlugin.py (tetrahedral mesh generation)
   • tetra_exporter.py (exports to .tetra format)

4. Enable both add-ons from the list

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3. Create and Export a Tetrahedral Mesh

1. Select a mesh in Object Mode

2. Use Shift + A > Mesh > Add Tetrahedralization

3. Adjust resolution and quality parameters, then confirm

4. With the resulting mesh selected, go to:

   File > Export > Tetrahedral Mesh (.tetra)
   

5. Choose a destination and export

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Unity Integration

The Unity importer (TetraImporter.cs) reads .tetra files and converts them into ScriptableObject assets of type TetrahedralMeshAsset, which contain:

• Vertex coordinates
• Tetrahedra vertex indices
• Automatically extracted edge indices

These can be used for simulations, visualizations, or custom mesh processing.

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.tetra File Format

The .tetra format is a simple text-based format with two main elements:

v x y z     # defines a vertex

t i j k l   # defines a tetrahedron by 0-based vertex indices

Example

# Vertices
v 0.0 0.0 0.0
v 1.0 0.0 0.0
v 0.0 1.0 0.0
v 0.0 0.0 1.0

# Tetrahedra
t 0 1 2 3

See docs/format_spec.md for full specification.

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Repository Structure

/blender/
  BlenderTetPlugin.py       - Tetrahedral mesh generation
  tetra_exporter.py         - .tetra format exporter

/docs/
  format_spec.md            - File format documentation

/examples/
  test_mesh.tetra           - Example .tetra mesh file

/unity/
  TetraImporter.cs          - Unity asset importer
  TetrahedralMeshAsset.cs   - ScriptableObject asset structure

README.md
LICENSE

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Credits

This project is based on the work of:

Matthias Müller – Ten Minute Physics YouTube: Ten Minute Physics Original plugin: BlenderTetPlugin.py

Included under the MIT License.

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License

This project is released under the MIT License. See the LICENSE file for details.

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Contributing

Contributions are welcome! Feel free to open issues or pull requests to:

• Improve Blender or Unity integration
• Extend the .tetra format
• Add support for metadata, regions, or visualization tools