The Cloc software implements the Super Space Clothoid model [1]. This is the reference version, developped by the authors and used for the simulations that you can find in the paper.

[1] Romain Casati, Florence Bertails-Descoubes, Super Space Clothoids, ACM Transactions on Graphics (2013).

Cloc is developped in C but has little python bindings named PyCloc. It has only been tested on Linux but you are welcome to share with us your experience with other OS (see the contacts section).

How to compile Cloc?

Cloc has few dependencies that you can find in most of the Linux distros.

  • Debian-like distros (Debian, Ubuntu, …):

     apt-get install build-essential cmake libatlas-base-dev python-dev cython python-numpy python-matplotlib
  • RedHat-like distros (RedHat, Fedora, CentOS):

     yum install cmake atlas-devel python-devel Cython numpy python-matplotlib pygtk2

Once all this depenencies are installed, unpack cloc.tgz and compile

tar xzf cloc.tgz
cd cloc

Starting with Cloc

The last command make should have started the script python/ that computes a simulation of a ring falling under gravity and shows the animation. To go further, you can have a look at the PyCloc documentation that contains nice tutorials.

Known bugs

Matplotlib version too old

If your matplotlib version is too old (< 1.1), this message will probably show up

ImportError: No module named animation

This is not a serious problem, it just prevent from displaying the simulation as an animation. Since the import is called just before displaying, this mean that the computation succeeded and Cloc is probably working.

A workaround could be to not use matplotlib.animation or to update matplotlib:

pip install --upgrade matplotlib

Sometimes, pip is called pip-python. You can check your matplotlib version with

python -c "import matplotlib as mpl; print(mpl.__version__)"


You are welcome to contact the authors for any comments, questions or improvements:

  • Romain Casati:
  • Florence Bertails-Descoubes: