Spine
About Spine
2D skeletal animation for games
Spine replaces traditional raster animation in games, providing smoother animations that are easier to produce. Animations can be created without needing more art and are so tiny that games can make extensive use of them.
Download Spine for free and give it a try right now for Windows, Mac, and Linux! Included with the trial are a number of example projects that show some of the possibilities when using Spine.
Spine Downloadhttp://esotericsoftware.com/spine-documentation/
Spine Documentation