Synfig Studio is an open-source, free 2D vector and timeline-based animation program. Synfig Studio can be used to create web animations, feature-film-quality animations, and advertisements.
These are the key features
Spatial resolution-independence:Most elements are vector-based and all layers are parametrically generated, hence even when changing the target resolution of a project, the only pixelation will occur in imported raster images, not the built-in components.
Temporal resolution independence: Animation keyframes are automatically interpolated and smoothed by the computer.
HDRI Processing: HDRI processing uses floating-point math to calculate the image. This allows canvases internal understanding of a greater range of pixel luminances, which results in better lighting effects and improved color composition.
Pentablet-friendly Tools: The draw tool already reads your favourite tablets' pressure sensitivity channels for natural line weighting and more!
Artist-oriented design: Synfig was designed with animation workflow in mind.
Synfig supports gradient paths, which are gradients that follow a drawn line. This allows artists to add soft shading to animations without having to paint it onto every frame.
Layers: Synfig supports many layers, including geometric, gradients and filters, distortions, transformations and fractal.
Synfig Studio is a rich feature-rich application that includes High Dynamic Range Imaging (HDRI), artist-oriented design, and path-based gradients.