Bones & IK
The bone tool builds a real skeleton on flat artwork: a chain of bones, a skinned mesh, and both forward and inverse kinematics. After Effects has no equivalent.
The pieces
| Piece | What it is |
|---|---|
| Bone | A segment with a length and a rotation, parented to the previous bone |
| Chain | A sequence of bones — an arm, a tail, a leg |
| Skinning | Linear blend skinning: each mesh vertex is influenced by nearby bones, weighted |
| FK | Forward kinematics — rotate a bone, everything downstream follows |
| IK | Inverse kinematics — move a target, the chain solves to reach it |
Two IK solvers are live: a closed-form two-bone solver, and FABRIK for longer chains.
Workflow
Pick the tool
Ctrl/⌘ + B, with a riggable leaf layer selected — a single shape or image layer.
Draw the chain
Click to place the root, then click again for each subsequent joint. The BoneOverlay draws the bones, joints and IK targets on the canvas.
Bind
The mesh is skinned to the skeleton. Each vertex picks up weighted influence from the bones near it, so the artwork deforms smoothly across a joint rather than tearing at it.
Pose
FK: rotate a bone and its children follow. Good for tails, antennae and anything whose motion originates at the root.
IK: add a target at the end of the chain and move the target. The solver finds joint angles that reach it. Good for arms and legs, where you care about where the hand or foot ends up and not about the elbow angle.
Keyframe
Poses are keyframeable. Set the playhead, pose the rig, and keys are written.
Use IK when the end of the chain has a job — planting a foot, holding a prop. Use FK when the motion travels outward from the root — a whipping tail. Most character work uses both, on different limbs.
CPU and GPU skinning
Both paths exist and produce the same result — the deformed mesh is normalised before it reaches the renderer, so the GPU path does not drift from the CPU one.
Editing the rig
The Rigging inspector tab holds chain editing, IK targets and pose controls. Every edit is a single undo step.
Bones or puppet?
| Bones | Puppet |
|---|---|
| Jointed, articulated motion | Squashy, organic, cloth-like motion |
| A defined skeleton exists | No obvious skeleton |
| You want IK — “put the hand there” | You want to grab and pull |
They are separate systems; use whichever the artwork suggests. See Puppet pins.
Related
- Rigging a logo
- The assistant’s
create_skeleton_rigandpose_skeletontools: Tool reference