Stretch Bone Creator

Creates helper bones whose scale automatically stretches and squashes based on a joint's rotation angle or its distance to a child bone. Set up muscle bulge, contraction, and squash-and-stretch without writing any expressions. Rotation mode measures the angle with quaternions (gimbal-lock free) relative to the rest pose. Generate a single helper bone, or all six (±X ±Y ±Z) radial helpers with a shared pivot at once for fast radial muscle setups. The UI supports Korean, English, Chinese, and Japanese, with adjustable axis, reference angle, min/max scale, and target axis.