https://github.com/zalo/tetsim

Javascript Tetrahedral FEM Simulation
https://github.com/zalo/tetsim

fem physics-simulation xpbd

Last synced: about 2 months ago
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Javascript Tetrahedral FEM Simulation

• Host: GitHub
• URL: https://github.com/zalo/tetsim
• Owner: zalo
• Created: 2021-10-28T00:24:16.000Z (about 3 years ago)
• Default Branch: main
• Last Pushed: 2023-12-28T22:18:37.000Z (about 1 year ago)
• Last Synced: 2024-05-01T13:53:42.772Z (8 months ago)
• Topics: fem, physics-simulation, xpbd
• Language: JavaScript
• Homepage: https://zalo.github.io/TetSim/
• Size: 7.48 MB
• Stars: 34
• Watchers: 6
• Forks: 7
• Open Issues: 1
• Metadata Files:
  • Readme: README.md

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README

        
# [TetSim](https://zalo.github.io/TetSim/)



  

      

  

      

    



Simulate Tetrahedral FEM Models in your browser in real-time using the GPU!

![Gif of TetSim in action](./TetSimDemo.gif)

This repo contains two proof-of-concept demos:

## [CPU Sim](https://zalo.github.io/TetSim/?cpu=true)

This one is a plain rehosting of [Miles Macklin and Matthias Müller's A Constraint-based Formulation of Stable Neo-Hookean Materials](http://blog.mmacklin.com/publications/#:~:text=A%20Constraint-based%20Formulation%20of%20Stable%20Neo-Hookean%20Materials) demo.  

I've broken the script into several ES6 Module pieces with the intention of improving reusability.

## [GPU Sim](https://zalo.github.io/TetSim?cpu=false)

This one rewrites the entire simulation as a set of GPU passes on Render Textures (gaining a **~20x speedup**).  This does NOT use the Neohookean energy/constraint function.  This is because the Neohookean function only converges well with Gauss-Seidel iterations (which are tricky to implement on the GPU (see: [Graph Coloring](https://erkaman.github.io/posts/gauss_seidel_graph_coloring.html)), and especially tricky to implement for this example dragon mesh, which has vertices with over 30 connecting tetrahedra).   Instead, this simulation uses [Matthias Müller's Robust Polar Decomposition](https://www.youtube.com/watch?v=YOBjHpoImu8) on the tetrahedra, which converges much faster (and with GPU-friendly Jacobi Iterations).

 - 20x faster

 - Even works on Mobile Devices (though Android devices behave strangely)

 - Not physically correct (doesn't incorporate deltaTime properly yet)

 # Building

This demo can either be run without building (in Chrome/Edge/Opera since raw three.js examples need [Import Maps](https://caniuse.com/import-maps)), or built with:

```

npm install

npm run build

```

After building, make sure to edit the index .html to point from `"./src/main.js"` to `"./build/main.js"`.

 # Dependencies

 - [three.js](https://github.com/mrdoob/three.js/) (3D Rendering Engine)

 - [esbuild](https://github.com/evanw/esbuild/) (Bundler)