# libigl - A simple C++ geometry processing library

![](tutorial/images/libigl-logo.jpg)

<https://github.com/libigl/libigl/>

libigl is a simple C++ geometry processing library. We have a wide functionality including construction of sparse discrete differential geometry operators and finite-elements matrices such as the contangent Laplacian and diagonalized mass matrix, simple facet and edge-based topology data structures, mesh-viewing utilities for OpenGL and GLSL, and many core functions for matrix manipulation which make [Eigen](http://eigen.tuxfamily.org) feel a lot more like MATLAB.

It is first and foremost a header library. Each header file contains a single function. Most are tailored to operate on a generic triangle mesh stored in an n-by-3 matrix of vertex positions V and an m-by-3 matrix of triangle indices F. The library may also be [compiled](build/README.html) into a statically linked library, for faster compile times with your projects.

We use the [Eigen](http://eigen.tuxfamily.org) library heavily in our code. Our group prototypes a lot in MATLAB, and we have a useful [conversion table](http://libigl.github.io/libigl/tutorial/matlab-to-eigen.html) from MATLAB to libigl/Eigen.

# Tutorial

As of version 1.0, libigl includes an introductory
[tutorial](http://libigl.github.io/libigl/tutorial/tutorial.html) that covers
its basic functionalities.

## Installation
Libigl is a *header* library. You do **not** need to build anything to install.
Simply add `igl/` to your include path and include relevant headers. Here is a
small "Hello, World" program:

```cpp
#include <igl/cotmatrix.h>
#include <Eigen/Dense>
#include <Eigen/Sparse>
#include <iostream>
int main()
{
  Eigen::MatrixXd V(4,2);
  V<<0,0,
     1,0,
     1,1,
     0,1;
  Eigen::MatrixXi F(2,3);
  F<<0,1,2,
     0,2,3;
  Eigen::SparseMatrix<double> L;
  igl::cotmatrix(V,F,L);
  std::cout<<"Hello, mesh: "<<std::endl<<L*V<<std::endl;
  return 0;
}
```

If you save this in `hello.cpp`, then you could compile this with (assuming Eigen
  is installed in /opt/local/include/eigen3):

```bash
gcc -I/opt/local/include/eigen3 -I./igl/ hello.cpp -o hello
```

Running `./hello` would then produce

```
Hello, mesh:
 0.5  0.5
-0.5  0.5
-0.5 -0.5
 0.5 -0.5
```

## Dependencies
Dependencies are on a per-include basis and the majority of the functions in libigl
depends only on the [Eigen](http://eigen.tuxfamily.org) library.

For more information see our [tutorial](tutorial/tutorial.html).

# Download
You can keep up to date by cloning a read-only copy of our GitHub [repository](https://github.com/libigl).

## How to contribute

If you are interested in joining development, please fork the repository and submit a [pull request](https://help.github.com/articles/using-pull-requests/) with your changes.

## License
libigl is primarily [MPL2](http://www.mozilla.org/MPL/2.0/) licensed ([FAQ](http://www.mozilla.org/MPL/2.0/FAQ.html)). Some files contain third-party code under other licenses. We're currently in the processes of identifying these and marking appropriately.

## Attribution
If you use libigl in your academic projects, please cite the papers we implement
as appropriate. To cite the library in general, you could use this BibTeX entry:

```bibtex
@misc{libigl,
  title = {{libigl}: A simple {C++} geometry processing library},
  author = {Alec Jacobson and Daniele Panozzo and others},
  note = {http://igl.ethz.ch/projects/libigl/},
  year = {2014},
}
```

# Contact

Libigl is a group endeavor led by [Alec Jacobson](http://www.cs.columbia.edu/~jacobson/) and [Daniele Panozzo](http://www.inf.ethz.ch/personal/dpanozzo/). Please
[contact us](mailto:alecjacobson@gmail.com,daniele.panozzo@gmail.com) if you have questions or comments. We are happy to get feedback!

If you're using libigl in your projects, quickly [drop us a
note](mailto:alecjacobson@gmail.com,daniele.panozzo@gmail.com). Tell us who you are and what you're using it for. This helps us apply for funding and justify spending time maintaining
this.

If you find bugs or have problems please use our [github issue tracking
page](https://github.com/libigl/libigl/issues).

### Copyright
2014 Alec Jacobson, Daniele Panozzo, Olga Diamanti, Kenshi
Takayama, Leo Sacht, Wenzel Jacob, Nico Pietroni, Amir Vaxman