Bone Animation

The concept of bone animation comes from 3D animation. It's a technique that produces animation by transforming bones (translation, rotation, scaling) to drive model changes.
LoongBones brings this technology into 2D animation, using bone transformations (translation, rotation, scaling) to drive image changes.

What are Bones

Bones can be understood as virtual sticks that can scale, rotate, and move. Bones have parent-child relationships. A bone can connect to a parent bone, and a parent bone can connect to multiple child bones.

For parent-child bones, unless specified otherwise, changes in a parent bone's translation, rotation, and scaling will drive all its child bones to change together. This type of change is generally called Forward Kinematics (FK).

This is the opposite of Inverse Kinematics (IK), where child bone changes cause parent bone changes. For detailed information about IK, see IK.