One to try: appleseed
It sometimes seems that the first thing any CG programmer with time on his or her hands does is to sit down and write an open source physically based renderer.
But what makes appleseed – yes, another open source physically based render engine – special is that it is being developed by VFX professionals, specifically with production in mind.
However, there is a more serious point. According to the development website: “We believe many high end rendering softwares used in production are too clunky, and we would like to show another way of doing things.”
So why another free renderer?
Addressing the obvious question in this thread on Blender Nation, developer François ‘Franz’ Beaune points out that the project actually predates LuxRender and Blender’s new Cycles engine.
Unlike other free renderers, appleseed is specifically intended to facilitate the kind of tricks used in real productions, sacrificing physical correctness for the sake of rendering time. It includes the option to mix physically based and non-physically based materials in the same scene.
According to Beaune: “We’re not trying to duplicate what LuxRender, Cycles or YafaRay already excel at. We’re trying to do something different by targeting addressing the problems that are not covered by most of the other open source renderers, like solid deformation motion blur.”
appleseed is still very much in alpha, and does not yet support displacement or programmable shading, so it’s more one to keep an eye on than one to use out of the box. If you want to play around, it is available for Windows, Mac OS X and Linux, and are exporters in development for Blender and Maya.