Freestyle stroke shaders

Photo Credit: Based on Charblaze model - CC0

Freestyle stroke shaders

Blender-Brussels is pleased to invite Folkert de Vries to give a workshop at F/LAT on how to write your own shaders for Freestyle, the now integrated non photorealistic renderer.

Folkert is actually working on a SVG exporter for Freestyle and for this workshop, he will share his knowledge of the Freestyle API and teach us how to write our own custom stroke shaders for the Freestyle renderer.

« The current shaders are mainly tech demos, almost without an exception written by the original Freestyle creators in 2004. I’d be very interested to see what we might think up.

The shader building process is indeed something that gives a lot of freedom to the individual both in terms of creativity and skill level. Basically all we need to manipulate is a set of stroke vertices. This goes from a simple for-loop manipulating the color of each point to displacing whole strokes with the use of vector math. Additionally it could solve a real problem for some people, or lead to other creative ideas. », says Folkert.

Sounds interesting to you? Then please subscribe to book a seat to this workshop by sending an email to juego (at) requiem4tv (dot) com. And yes, subscription is mandatory.


Folkert started the workshop by showing us the Blender addon he has been working on: the SVG exporter for Freestyle. This addon allows in a simplified manner to export Freestyle defined line styles in an SVG file. It also permits to export animations, which is a great and never before seen feature.

An SVG animation rendered with the Freestyle SVG exporter

After playing around with it, he introduced us to the wonders of the Freestyle Python API. Some of us then started playing with it while others continued on experimenting with the SVG exporter. This lead to interesting discussions about the possibilities of both approaches and ended up in some debugging or more like feature requests regarding the SVG exporter.

As Folkert wraps it up:

The Blender-Brussels is a series of monthly free and open workshops dedicated to Python creative coding using Blender. Started by François Zajéga and Julien Deswaef in 2012, these have become a regular meeting point for anyone interested in experimenting with code. It works as a communal space to exchange ideas and share knowledge as a way to learn. All results of these practices − exercises and documentation produced during the workshop − are shared online under an open source license.

This event is hosted at F/LAT − 45, rue du Canal − 1000 Brussels on Saturday 20th December 2014, starting at 09:00 and finishing at 17:00.

This event is funded by:


Digital Arts Commission of the Wallonia-Brussels Federation