Animation in Spine is done by attaching images to bones, then animating the bones. This is called skeletal or cutout animation and has numerous benefits over traditional, frame-by-frame animation:
Smaller size Traditional animation requires an image for each frame of animation. Spine animations store only the bone data, which is very small, allowing you to pack your game full of unique animations.
Art requirements Spine animations require much fewer art assets, freeing up time and money better spent on the game.
Smoothness Spine animations use interpolation so animation is always as smooth as the frame rate. Animations can be played in slow motion with no loss in quality.
Attachments Images attached to bones can be swapped to outfit a character with different items and effects. Animations can be reused for characters that look different, saving countless hours.
Mixing Animations can be blended together. For example, a character could play a shoot animation while also playing a walk, run or swim animation. Changing from one animation to another can be smoothly crossfaded.
Procedural animation Bones can be manipulated through code, allowing for effects like shooting toward the mouse position, looking toward nearby enemies, or leaning forward when running up hill.
The dopesheet is at the heart of animating. It provides a detailed view of all the timelines that make up an animation and allows fine adjustments to be made to the animation’s timing.
Instead of drawing rectangles, meshes allow you to specify a polygon inside your image. This improves the fill rate because pixels outside the polygon won’t be drawn, which is especially important for mobile game. Meshes also enable FFD and skinning.
The graph editor defines bezier curves for interpolation between keys, allowing for much more life-like movement.
Free-Form Deformation (FFD) allows you to move individual mesh vertices to deform the image. FFD allows meshes to stretch, squash, bend and bounce in ways that aren’t possible using rectangular images.
Constraints can be defined to animate using inverse kinematics (IK) and the Pose tool makes use of IK to quickly pose a skeleton.
Skins allow switching between sets of attachments. They provide organization for attachments and enable animations that change attachments to be reused for different characters.
Spine exports animation data in its own, documented JSON and binary formats which is ideal for use with the Spine runtimes. Spine can also export animated GIFs, PNG or JPG image sequences and AVI or QuickTime video.
29 June, 2017
14 May, 2015