Freestyle is a software for Non-Photorealistic Line Drawing rendering from 3D scenes. It is designed as a programmable interface to allow maximum control over the style of the final drawing: the user "programs" how the silhouettes and other feature lines from the 3D model should be turned into stylized strokes using a set of programmable operators dedicated to style description. This programmable approach, inspired by the shading languages available in photorealistic renderers such as Pixar's RenderMan, overcomes the limitations of integrated software with access to a limited number of parameters and permits the design of an infinite variety of rich and complex styles. The system currently focuses on pure line drawing as a first step. The style description language is Python augmented with our set of operators. Freestyle was developed in the framework of a research project dedicated to the study of stylized line drawing rendering from 3D scenes. This research has lead to two publications  ,  .
In 2008, Freestyle get a new life, completely outside ARTIS or INRIA: it was the basis of one of the 6 Google Summer of Code projects awarded to the Blender Foundation (http://www.blender.org/ )! The goal of the project was to integrate Freestyle to the well known free 3D modeler Blender, as its standard NPR line-drawing renderer. Maxime Curioni (under the mentoring of Jean-Luc Peurière from the Blender Foundation), is currently making the integration. First beta versions are publicly available, and tested by enthusiasts around the web.