Synfig Studio creates vector based animations and multimedia files. Is free and available to install on all major operating systems.
Layers are generated dynamically, supports math calculations, includes tools for drawing. Supports gradients and paths, add effects, filters, distorsions such and organize layers.
Is a 2D animation tool with graphical user interface and back-end, supports colors that can be modified or applied in resolution independent mode.
Can export files to image format (GIF) or video (AVI, MPEG) and more.