Natron is an open-source – crossplatform – nodal – compositing software for OS X, LINUX and WINDOWS.
It supports OpenFX plugins and have many nice other features.

I believe there can never be too many software applications to be aware of that could improve and extend your art creation.
This one might become a very valuable application to all Carrara animators. If you are in the needs for a compositing software to add some extra visuals to your Carrara rendered animations there is a very promising project in active development.

Natron compositor

Natron Compositor, looks like inspired by The Foundry Nuke,  offers advanced VFX features to enhance your imaging. I believe we can get some really fascinating result combining Carrara and Natron Compositor!
In addition this one is opensource and free!
Check it out
http://natron.inria.fr/

Shall we do some VFX with Carrara and Natron?

By the way, if you are a person with skills of programming, you can help this project to become even greater, the team behind Natron is looking for some assistance to get this tool to the masses.