Elbows that collapse, hips that pinch, forearms that twist into candy wrappers — fixed with shape keys the bones drive, fitted to your own animations, and measured frame by frame in Blender and in Unity.

Linear skinning loses volume wherever two bones meet. Blender's Corrective Smooth (Delta Mush) fixes it beautifully — but it is slow, and no game engine has it. JointForge bakes what it does into ordinary corrective shape keys, drives them from the bones, and fits them across every frame of your animations.

What you get

• Find Joints — every bone that bends skin, ranked by how far plain skinning is from the Delta Mush reference at the widest bend your animations reach.
• Build Correctives — corrective keys per joint, per axis, fitted on single bends, your animation frames and mixed whole-body poses.
• Measure on Animation — worst and typical distance from the reference, before and after, on every frame.
• Export for Unity — FBX with blend shapes, a driver table and a ready component.

Measured

• UE5 mannequin, four animations, 513 frames: worst 41.6 → 18.6 mm, typical 3.21 → 0.72 mm, no frame worse.
• CesiumMan: worst 53.2 → 21.0 mm, typical 14.5 → 3.2 mm.
• Unity 6: blend shapes arrive at the same size; the component's weights match the Blender drivers within 0.004 on 99% of values.

Blender 4.2 to 5.2. No AI, no cloud, no account.