Synfig Studio (Synfig) is a free and open source 2D vector graphics and timeline-based animation software. Developed by Synfig.org
License: Open Source
Synfig Studio is a powerful tool aimed at users who need advanced animation capabilities, including bone rigging and customizable interfaces, but it has a steeper learning curve. Tupi, on the other hand, is more user-friendly and suitable for beginners focusing on 2D animations, though it lacks some of the advanced features found in Synfig.